Recent Advances

#### **Chapter 7**

## Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response

*Veda Krishnan, Monika Awana, Debarati Mondal, Piyush Verma, Archana Singh and Shelly Praveen*

#### **Abstract**

Limiting starch bioavailability by modifying food matrix dynamics has evolved over the decade, which further envisions low glycemic starch prototypes to tackle chronic hyperglycemia. The dense matrix of whole grain foods like millets and cereals act as a suitable model to understand the dynamics of binary food matrix interactions between starch-lipid, starch-protein & starch-fiber. The state and types of matrix component (lipid/protein/fiber) which interact at various scales alters the starch micro configuration and limits the digestibility, but the mechanism is largely been ignored. Various in-vitro and in-vivo studies have deciphered the varied dimensions of physical interactions through depletion or augmentation studies to correlate towards a natural matrix and its low glycemic nature. The current chapter briefly encompasses the concept of food matrix types and binary interactions in mediating the glycemic amplitude of starch. We comprehensively elaborated and conceptually explained various approaches, which investigated the role of food matrices as complex real food systems or as fundamental approaches to defining the mechanisms. It's a fact that multiple food matrix interaction studies at a time are difficult but it's critical to understand the molecular interaction of matrix components to correlate in-vivo processes, which will assist in designing novel food prototypes in the future.

**Keywords:** starch, digestibility, food matrix, binary interactions, glycemic response

#### **1. Introduction**

Starch is one of the major constituents of reserve food material, which serves as fuel for the human body. The calorific value of starch is 17.5 kJ/g, which is not only responsible for most of the metabolic functions but also acts as a crucial regulatory adjunct to control energy balance. Starch existed as the major dietary nutrient since time immemorial but the dietary transition with enriched refined products as well as carbaholic staples led to the unprecedented increase in the pre-diabetic and diabetic population with characteristic chronic hyperglycemia. Hence glycaemic response (GR) eliciting potential of food known as the glycemic index (GI) or glycemic potential (GP) are major aspects to understand as well as to fine-tune. In a food matrix,

starch bioavailability is modulated by the microstructure (cell wall, membrane, cell layers, granular size, etc.) as well as its dense composition (macro and micronutrients) [1]. Based on the interacting components food matrix interactions are classified as binary (two-component), ternary (three-component), and quaternary (four-component) [2–6]. Types of binary interactions and their effect on starch bioavailability are depicted in **Figure 1**.

Among these, a binary component has gained great importance and has been extensively characterized by component depletion or addition studies under in-vitro conditions [7, 8]. The observed low GP of whole grain foods like millets, pigmented rice has been well correlated with such matrix interactions present endogenously, while high GI has also been reported to lower by exogenous addition of such matrix components [9–11]. The state and types of matrix component (lipid/protein/fiber) which interacts at various scales have also been known to alter the starch micro configuration (repeat, reconstruct the sentence limiting the digestibility, result in lowering the glycemic response [9, 12].

Binary interactions have been majorly characterized using nutrient-sensing fluorescent probe-based confocal laser scanning microscopy (CLSM), where the proximity as well as encapsulating effect of matrix components limiting the starch hydrolytic metabolic enzymes have been observed [13, 14]. Further, the effect of

#### **Figure 1.**

*Types of binary interactions and its effect on starch bioavailability. Binary interactions modulate physiochemical, structural, and biological attributes limiting starch digestibility as well as ultimate glycemic response.*

*Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

such interactions on starch functional aspects like hydration, enzymatic cleavage, or enthalpy have been delineated using differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) assisted in revealing the structural alterations associated with starch in the matrix after component depletion or addition. Rapid visco analysis (RVA) revealed that viscosity and pasting parameters were found inversely associated with in-vitro starch digestibility. The effect of matrix components in retaining the matrix, granule stability, preventing the expansion of granules as well as limiting the glycolytic enzyme attack has been endorsed using this technique [15, 16]. Other than affecting the swelling of starch granules by reducing the contact with carbolytic enzymes, the effect of such binary interactions in altering the molecular configuration (digestion sensitive A or B type to resistant V-type) of starch was envisioned and characterized using X-ray diffraction (XRD) and Fourier transform infrared microscope (FTIR).

Among the binary interactions, the most relevant in limiting the glycemic amplitude includes starch-lipid, starch-protein & starch-fiber dynamics.

#### **1.1 Starch-lipid interactions**

Even though well compartmentalized, starch and lipids do interact endogenously in real food systems. Lipid content ranges from 0.2–7% in cereals, with the least reported in rice and maximum reported in the case of oats & pearl millet [17]. A balanced distribution of neutral, glycol, and phospholipids along with free fatty acids have been reported in most of the food matrices, assist in energy as well as membrane structure & functions [17]. Curiosity towards food matrix interactions underlined a striking correlation between high lipid content [18] and low GR, which initiated binary (starch-lipid) interaction studies [7, 8]. Endogenous and exogenous lipid content have found to have low in-vitro starch digestibility along with superior resistant starch (RS) fraction. The effect of endogenous and exogenous lipid types have recently shown to have an effect in increasing starch-lipid complexation enriching RS content in red rice [9, 10]. Ye et al. [11] suggested that among lipids and proteins, starch digestibility is most affected by lipids as it affects swelling of granules, reduces the contact with carbolytic enzymes as well as alters the molecular structure from A-type into resistant V-type pattern. The long hydrophobic tail of lipid entering the cavity-like structure of amylose enables starch to form a stable complex, thereby hindering the accessibility of starch to enzyme attack [11]. In the case of mung bean flour, in-vitro starch digestibility and GI were increased significantly when endogenous lipids were removed [19]. Previous studies by Panyoo et al. [12], Krishnan et al. [9] have mentioned that stable starch-lipid complex results in a twist in digestibility phenotype into a digestion resistant fraction (RS-V), which caters to the gut microflora. As stated above, Copeland et al. [20]; Wang and Copeland [21] suggested this inclusion complex of starch-lipid also has an immense role in the food industry such as lowering solubility, swelling power, starch gelatinization, retrogradation, and enzyme action.

Starch-lipid complexes can exist inherently within the food matrix, or they may be produced by exogenous applications. A study by Obiro et al. [22]; reported that this complexation is mainly influenced by non-covalent interactions (hydrogen bonds, hydrophobic interactions, van der Waals interactions, and so on). Hydroxyl groups α-(1,4) are situated on the outer surface whereas methylene and oxygen groups present in the inner region of the complex strengthen the formation of starch-lipid

complexes. Considering all positive impacts of starch-lipid complex, there are few factors (chain length of amylose, amylopectin, fatty acids, degree of unsaturation) that mostly govern the degree of complexation [10]. Various researchers stated that amylose acts as the primary constituent to interact with lipid molecules, while few reports supported the role of amylopectin chain length to form the complex [23, 24]. It has been reported from various studies that starch-lipid complexability has been increased with the longer chain length/degree of polymerization (DP) which highlights the formation of crystalline structure [25]. In addition to the effect exerted by the chain length of starch components, processing conditions like cooking also affect starch-lipid interaction. Kaur et al. [8] suggested amylose-lipid complexation enhanced with amylose chain length and increased with cooking time. Experiments highlighted the stability of starch-lipid inclusion complex formation mainly based on the types of fatty acids accommodated inside the helical cavity [26]. Different reports exist on the type of fatty acid for stable starch-lipid complexation. One school of thought suggests that the stability of the S-L complex could be enhanced by increasing the aliphatic chain length of fatty acids as well as melting temperature (from 8–10). On the other hand, another dimension highlights that smaller carbon chain length fatty acids might be more soluble into the aqueous solution and less stable also [27, 28]. Tufvesson et al. reported C14 as the most stable conformation than C16 or C18 while other explained C16 or C18 is better in the case of complexability [28]. Therefore, saturated fatty acid (SFA) with increased chain length can easily form a stable complex which further affects enzymatic accessibility due to resistance against carbolytic enzymes. Studies over decades highlighted that only SFA can be able to form a strong stable S-L complex with increasing chain length in a temperaturedependent manner whereas an inverse relationship has been found for unsaturated fatty acid (UFA) [26, 28]. A report from Zheng et al. [29] stated that chain length and degree of unsaturation have a role in the compact structure of starch-lipid formation. In addition to this, Kawai et al. [30] & Meng et al. [31] revealed starch-UFA complex showed resistance by formatting a stable complex to digestive enzyme action. The degree of complexability of FA in the case of maize starch ranged from 11.60–26.31% according to Sun et al. report [32]. Moreover, it has been explained from Sun et al. [32] RS is also enriched with the degree of unsaturation from 0 to 2%. In addition, thermal properties are also greatly affected by this S-L complex. Thermal complexes are mainly classified into two types of complexes as type I (90–115°C), type II (115–130°C) depending on the melting temperature. Studies from previous research have already highlighted that developed type II complex is more resistant to the digestive enzymes as compared to type I complex [33]. But Sun et al. [32] unraveled that maize starch-linoleic acid (MS-LOA) primarily formed as type I complex while maize starch-stearic acid (MS-SA) belonged to type I & type II complex. The reason behind this could be the large steric hindrance associated with LOA than SA which showed less accessibility of enzymes and inhibits ultimate glucose release. Cheng et al. [34] also used molecular dynamics to study amylose and linoleic acid structural analysis and conformational changes during complexation. On the continuation with Cheng et al., recently another research group of Schahl et al. [35] revealed the molecular structural complex using 13 NMR spectroscopy where they have taken quantum DFT approach affected by amylose size fragment and specific intramolecular hydrogen bonds. Hence, all the V-type complexes produced due to the addition of lipids act as a stable resistant structure against all digestive enzymes which further lowers glycemic response.

#### **1.2 Starch-protein interactions**

Proteins, mostly in the form of amino acids, and enzymes, are the predominant component in the food matrix, other than starch and fat [36]. Apart from the nutritional quality, proteins act as the major microstructural framework in a food matrix and hence also act as a physical barrier towards starch hydrolysis [37]. An interesting correlation among the reduction in insulinemic and glycemic responses by increasing the protein content in starchy crops led to the possibility of starch-protein interplay. Among the protein types, albumin, glutenins, and globulins aid in the gluing of protein bodies into a matrix enveloping the starch granules, which act as a barrier for starch digestion [38]. The existence of a protein barrier encircling the starch granule was validated using the pronase enzyme which dissociates the protein matrix and results in a considerable increase in-vitro starch digestibility [39]. Annor et al. [40] reported that the hypoglycemic characteristic of Kodo millet was related to the protein encircling the starch granules. Ren et al. [41] also reported that there was a fast increment in in-vivo GI and in-vitro starch digestibility of foxtail millet flour due to the lack of starch-protein complex after deproteination. Various studies have reported that the presence of gluten has an impact on the pace of starch digestion, resulting in reduced glycemic response [42, 43]. Gluten develops a visco-elastic and thick network that entraps starch granules, as well as a compact and stable structure that prevents starch granules from expanding and leaching during cooking, resulting in reduced accessibility of enzyme and slow-release properties [44]. To study the impact of protein removal from wheat products (bread) on blood glucose, healthy individuals were given meals of white bread prepared either from normal or gluten-free flour. It was observed that there was a considerable increase in blood glucose after consuming bread prepared from gluten-free flour. This led to an increase in digestion rate in-vitro and declined the starch mal-absorption in vivo as studied via breath-H2 measurements, but this impact was not restored when the gluten was later added back to the gluten-free flour. The possible mechanism behind this may be all-purpose wheat flour is made up of granules with a starch core enveloped by a protein network that inhibits the hydrolysis rate in the small intestine lumen [45]. Recently, Lu et al. [46] revealed that in the small intestine, amino acids generated from enzymatic hydrolysis of rice protein inhibited the porcine pancreatic α-amylase activity. The protein content of rice flour was shown to be negatively associated with rapidly digestible starch (RDS) and slowly digestible starch (SDS), while positively with RS [47], on the other hand, the total protein content of rice grain was found to be inversely correlated with invivo GI [48].

Other than endogenous factors, processing (thermic/mechanical) has been found to have an effect in altering the level of interaction between protein-starch molecules, influencing the overall digestibility [49]. Pasini et al. [50] found that in-vitro digestion of wheat protein has been considerably reduced at elevated cooking temperatures (>180°C) due to the development of high molecular weight protein aggregates which are stabilized by strong irreversible linkages, distinct from hydrophobic and/or disulfide bonds that could be prevalent at low temperatures (100°C). Furthermore, it has been found that "appropriate" kneading/mixing promotes the development of a protein matrix (gluten) via disulfide linkages. Moreover, if extreme kneading/mixing is performed, the matrix loses strength as the linkages break and glutenin particles are fragmented into smaller fragments, which helps digestive enzymes access the starch and thus increases the starch digestibility [51].

Protein-enriched food formulations have also been found to impact the overall GI and thus assist in developing diabetic-friendly foods. Formulations based on proso millet starch and different protein mixtures (15% zein + 10% whey protein isolate + 15% soy protein isolate) reported that protein types reduced the RDS levels and enhanced RS levels from 4.49% to 11.73%. The blend comprising of corn starch (10%) and whey protein isolate had a considerably higher concentration of RS and low RDS as compared to pure corn starch. This could be due to the increased protein matrix enveloping starch networks, preventing amylolytic attack. When soy protein was added to maize starch, RDS was reduced while SDS and RS were increased [52]. The addition of 51% rice protein in wheat starch along with cellulose reduced RDS level, whereas the addition of protein from pea proteins (82%), maize (95%), soy (94%), and wheat (86%) did not affect RDS levels [13]. Bio-mimicking interactions in corn grains using microencapsulation of corn starch by zein protein have been reported with lowered starch digestibility [53]. Furthermore, starch coupled with amino acids or protein via the Maillard process has been demonstrated to limit the starch swelling, solubility as well as digestion rate [54], however, potential negative effects due to glycated product consumption must be examined in detail [55].

#### **1.3 Starch-fiber interactions**

Dietary fiber (DF), which consists primarily of non-starch polysaccharides found in plant cell walls, is an essential part of the food matrix [56]. DF types present in any food matrix are classified based on their water solubility and fermentability. Lignin, cellulose, and hemicelluloses are the major water-insoluble DF that get less fermented while the water-soluble DF includes pectin, mucilage, and gums and gets fermented properly in the small intestine [57]. Among the types, insoluble DF has been reported to be more useful in decreasing the GI as compared to their soluble fraction [58] as most of the common cereals contained a low level of naturally occurring soluble DF [59]. The endogenous fibers encircle the starch granules forming a starch-fiber network in the matrix, bio-mimicking an intact microstructure (plant cell/tissue) result in reduced enzyme accessibility and altered digestibility. Dense matrix composition in fiber content has been positively correlated to minimal postprandial GR after consumption in the case of barley, wheat, psyllium husk, and oats. This has been majorly attributed to the effect of insoluble DF in reducing starch bio accessibility as well as bioavailability [60, 61]. On the other hand, soluble DF like inulin has been found to form a protective barrier surrounding the starch granules, reducing starch swelling and release of amylose thus resulting in low viscosity values. This reduced the accessibility of starch-degrading enzymes that affect the in vivo starch digestibility and GI [62]. Among the studied types, β-glucan and guar gum have been reported to reduce the enzyme diffusion kinetics and thus the rate of carbohydrate digestion, eventually resulting in to slow down the gastric emptying and lower the liberation and absorption of glucose in the small intestine [63, 64]. The endogenous presence of β-glucans (native-form) in oats have been found to have an enveloping role towards starch and protein, thus reducing the enzyme accessibility, in turn, lowered starch digestibility and postprandial glycemia [65].

Endogenous presence, as well as exogenous addition of cellulose (insoluble fiber), has considerably reduced the α-amylase activity via mixed-type inhibition resulting in lowered in-vitro starch digestion [66]. The reduction of α-amylase activity was found to be positively linked with cellulose content, and α-amylase was found to be non-specifically linked on the surface of cellulose, reducing starch hydrolysis.

#### *Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

Interaction study between pectin and digestive enzyme (amyloglucosidase) showed a similar pattern, where pectin resulted in the conformational alteration in an enzyme that impeded substrate access and slower digestion rate of long amylopectin chains [67]. Luo and Zhang [68] aimed to mimic the microstructure of endosperm tissue by constructing a starch in a whole-grain-like structural form using calcium-induced alginate gelation in the presence of β-glucan and starch.

Processing strategies, as well as formulations with exogenous addition of fiber types, have also been found to reduce the in-vitro starch digestibility and GI of foods [69]. The addition of fibers like xanthan gum, glucomannan, and agar in rice lowered the starch digestibility in-vitro and in-vivo [70, 71]. However, no relationship was observed between native fiber content (0.5%) and in-vivo starch digestibility in rice, even though the fiber level was certainly too less to have any influence on starch digestion [48]. Reduction in blood glucose [72] and in-vitro starch digestibility [73] was observed in wheat products after adding β-glucan. β-Glucan has been assumed to improve viscosity, which could have lowered the rate of gastric emptying [72] and lowered the rate of diffusion of starch digestive enzymes. Vegetables like *Moringa oleifera* leaves and okra were found to reduce the glycemic response of various foods. When 10% okara was added to rice noodles, blood glucose levels significantly reduced [74]. Broccoli fiber addition in a potato diet has proved to assist in decreasing the GI by increasing RS content [75]. However, a 30% decrease in GI in the same sample was observed when studied in-vivo. Hardacre et al. [76] showed that fibers with comparable viscosities resulted in variation of in- vitro starch digestion and hypothesized that few fibers may inhibit certain enzymes in a non-competitive manner as a chemical barrier. An interesting observation reported by Sciarini et al. [69] was that, the addition of up to 5% soluble (Inulin) and insoluble fibers (oat fiber and type IV RS) enhanced the starch digestibility in GF bread, while further increase resulted in a reduction in starch digestibility. The initial observed increase could be due to the altered bread crumb structure while a higher percentage of fiber could have established a staple starch-fiber network and thus reducing the digestibility. The impact of RS addition in pasta structure on native starch digestibility was studied by Gelencser et al. [77]. They reported that kinetic characteristics were not considerably variable between the control and RS-added samples, whereas the starch digestibility was considerably low in the RS-added samples, signifying a decrease in absolute glucose release during amylolysis. The addition of RSII (7.5%) and RSIV (10%) in pasta showed a decrease in in-vitro starch digestibility and GI [78]. Furthermore, larger DF concentrations also might play role in confining the starch inside the pores, preventing its hydrolysis. Mkandawire et al. [79] discovered that adding up to 50% cellulose (w/w starch) to sorghum flours had no significant impact on the RS level. DF, on the other hand, enhanced the solution viscosity in-vivo, and therefore may slow starch degradation by restricting enzyme mobility, as gums do, and hence slowing digestion rate in total [63].

In this direction, several animal studies have been carried out to study the effect of adding fiber on starch bioavailability or glucose release. The supplement of insoluble cereal DF from oat leads to enhanced insulin sensitivity in obese mice [80]. Further studies conducted by Weickert et al. [81] revealed that oat DF and purified wheat can enhance the postprandial insulin secretion hormones which further improved the postprandial carbohydrate metabolism. The high level (500 mg/kg body weight) of oat β-glucan or 4% barley β-glucan resulted in considerable enhancement of insulin resistance in insulin-resistant mice model and the impact was concentration-dependent [82, 83]. β-Glucan was found to inhibit the intestinal disaccharides' activities

in-vitro and in-vivo, which led to slow starch digestion rate [84]. In the diabetic mice model, β-glucan considerably repaired and increased the integrity of pancreatic islet β-cell and tissue structures [85]. Overall, the type and concentration of fiber have a customized effect on the food matrix. Comprehensive list of various food components added to starch and their effect on starch digestibility is tabulated in **Table 1**.



*Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

#### **Table 1.**

*List of various food components added to starch and their effect on starch digestibility.*

#### **2. Conclusion**

Binary interactions among the nutrient types and starch mediate the glycemic amplitude of real food systems. Among the binary interactions (starch-lipid, starchprotein, starch-fiber), the role has been extensively characterized in limiting the enzyme penetrance, altering the molecular configuration, starch digestibility, and thus in turn GR. Understanding such binary interactions, not only shares a logical explanation for the low GI of whole-grain foods but also the immense role of such cereals in diabetic-friendly foods. Even though the existing rationale supports the fact that multiple food matrix interaction studies at a time are difficult, it's indeed vital to study ternary (three-way) and quaternary (four-way) interactions and their role in limiting the glycemic response. Finally, it's important to keep in mind that altering starch's nutritional qualities can also change its desired physicochemical and sensory qualities, affecting food quality that should be considered while developing novel foods.

### **Conflict of interest**

The authors declare no conflict of interest.

### **Author details**

Veda Krishnan1 \*, Monika Awana1 , Debarati Mondal1 , Piyush Verma<sup>2</sup> , Archana Singh1 and Shelly Praveen\*

1 Division of Biochemistry, ICAR-Indian Agricultural Research Institute (IARI), New Delhi, India

2 School of Pharmaceutical Science and Technology, Sardar Bhagwan Singh University, Dehradun, Uttarakhand, India

\*Address all correspondence to: veda.krishnan@icar.gov.in, vedabiochem@gmail.com and shelly.parveen@icar.gov.in

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

#### **References**

[1] Li Q, Shi S, Du SK, Dong Y, Yu X. Starch–palmitic acid complex formation and characterization at different frying temperature and treatment time. LWT. 2021;**136**:110328. DOI: 10.1016/j.lwt. 2020.110328

[2] Wang J, Jiang X, Zheng B, Zhang Y. Structural and physicochemical properties of lotus seed starchchlorogenic acid complexes prepared by microwave irradiation. Journal of Food Science and Technology. 2021;**58**:4157- 4166. DOI: 10.1007/s13197-020-04881-w

[3] Krishnan V, Awana M, Singh A, Goswami S, Vinutha T, Kumar RR, et al. Starch molecular configuration and starch-sugar homeostasis: Key determinants of sweet sensory perception and starch hydrolysis in pearl millet (*Pennisetum glaucum*). International Journal of Biological Macromolecules. 2021;**183**:1087-1095. DOI: 10.1016/j.ijbiomac.2021.05.004

[4] Krishnan V, Rani R, Awana M, Pitale D, Kulshreshta A, Sharma S, et al. Role of nutraceutical starch and proanthocyanidins of pigmented rice in regulating hyperglycemia: Enzyme inhibition, enhanced glucose uptake and hepatic glucose homeostasis using in vitro model. Food Chemistry. 2021; **335**:127505. DOI: 10.1016/j.foodchem. 2020.127505

[5] Krishnan V, Mondal D, Thomas B, Singh A, Praveen S. Starch-lipid interaction alters the molecular structure and ultimate starch bioavailability: A comprehensive review. International Journal of Biological Macromolecules. 2021;**182**:626-638. DOI: 10.1016/j. ijbiomac.2021.04.030

[6] Krishnan V, Awana M, Rani AR, Bansal N, Bollinedi H, Srivastava S, et al. Quality matrix reveals the potential of Chak-hao as a nutritional supplement: A comparative study of matrix components, antioxidants and physicochemical attributes. Journal of Food Measurement and Characterization. 2021;**15**:826-840. DOI: 10.1007/s11694-020-00677-w

[7] Henry CJK, Lightowler HJ, Newens KJ, Pata N. The influence of adding fats of varying saturation on the glycaemic response of white bread. International Journal of Food Sciences and Nutrition. 2008;**59**:61-69. DOI: 10.1080/ 09637480701664183

[8] Kaur B, Ranawana V, Teh AL, Henry CJK. The glycemic potential of white and red rice affected by oil type and time of addition. Journal of Food Science. 2015;**80**:H2316-H2321. DOI: 10.1111/1750-3841.13070

[9] Krishnan V, Mondal D, Bollinedi H, Srivastava S, Ramesh SV, Madhavan L, et al. Cooking fat types alter the inherent glycaemic response of niche rice varieties through resistant starch (RS) formation. International Journal of Biological Macromolecules. 2020;**162**:1668-1681. DOI: 10.1016/j.ijbiomac.2020.07.265

[10] Krishnan V, Awana M, Samota MK, Warwate SI, Kulshreshtha A, Ray M, et al. Pullulanase activity: A novel indicator of inherent resistant starch in rice (*Oryza sativa* L). International Journal of Biological Macromolecules. 2020;**152**:1213-1223. DOI: 10.1016/j. ijbiomac.2019.10.218

[11] Ye J, Hu X, Luo S, McClements DJ, Liang L, Liu C. Effect of endogenous proteins and lipids on starch digestibility in rice flour. Food Research International. 2018;**106**:404-409. DOI: 10.1016/j. foodres.2018.01.008

[12] Panyoo AE, Emmambux MN. Amylose-lipid complex production and potential health benefits: A mini-review. Starch-Starke. 2017;**69**:1600203. DOI: 10.1002/star.201600203

[13] Lopez-Baron N, Gu Y, Vasanthan T, Hoover R. Plant proteins mitigate in vitro wheat starch digestibility. Food Hydrocolloids. 2017;**69**:19-27. DOI: 10.1016/j.foodhyd.2017.01.015

[14] Jin Z, Bai F, Chen Y, Bai B. Interactions between protein, lipid and starch in foxtail millet flour affect the in vitro digestion of starch. CyTA-Journal of Food. 2019;**17**:640-647. DOI: 10.1080/19476337.2019.1628107

[15] Baxter G, Zhao J, Blanchard C. Albumi significantly affects pasting and textural characteristics of rice flour. Cereal Chemistry. 2010;**87**:250-255. DOI: 10.1094/CCHEM-87-3-0250

[16] Chung HJ, Liu Q, Lee L, Wei D. Relationship between the structure, physicochemical properties and in vitro digestibility of rice starches with different amylose contents. Food Hydrocolloids. 2011;**25**:968-975. DOI: 10.1016/j.foodhyd.2010.09.011

[17] Price PB, Parsons JG. Lipids of seven cereal grains. Journal of the American Oil Chemists Society. 1975;**52**(12):490-493. DOI: 10.1007/BF02640738

[18] Li Q, Wu QY, Jiang W, Qian JY, Zhang L, Wu M, et al. Effect of pulsed electric field on structural properties and digestibility of starches with different crystalline type in solid state. Carbohydrate Polymers. 2019;**207**:362- 370. DOI: 10.1016/j.carbpol.2018.12.001

[19] Hou D, Zhao Q, Yousaf L, Xue Y, Shen Q. In vitro starch digestibility and estimated glycemic index of mung bean (*Vigna radiata* L.) as affected by

endogenous proteins and lipids, and exogenous heat-processing methods. Plant Foods for Human Nutrition. 2020;**75**:547-552. DOI: 10.1007/ s11130-020-00845-9

[20] Copeland L, Blazek J, Salman H, Tang MC. Form and functionality of starch. Food Hydrocolloids. 2009;**23**:1527-1515. DOI: 10.1016/j. foodhyd.2008.09.016

[21] Wang S, Copeland L. Molecular disassembly of starch granules during gelatinization and its effect on starch digestibility: A review. Food and Function. 2013;**4**(11):1564-1580. DOI: 10.1039/D1FO00729G

[22] Obiro WC, Sinha Ray S, Emmambux MN. V-amylose structural characteristics, methods of preparation, significance, and potential applications. Food Reviews International. 2012;**28**(4):412-438. DOI: 10.1080/ 87559129.2012.660718

[23] Wang S, Wang J, Yu J, Wang S. Effect of fatty acids on functional properties of normal wheat and waxy wheat starches: A structural basis. Food Chemistry. 2016;**190**:285-292. DOI: 10.1016/j. foodchem.2015.05.086

[24] Eliasson AC. Interactions between starch and lipids studied by DSC. Thermochimica Acta. 1994;**246**:343-356. DOI: 10.1016/0040-6031(94) 80101-0

[25] Gelders GG, Vanderstukken TC, Goesaert H, Delcour JA. Amylose–lipid complexation: A new fractionation method. Carbohydrate Polymers. 2004;**56**:447-458. DOI: 10.1016/j. carbpol.2004.03.012

[26] Eliasson AC, Krog N. Physical properties of amylose-monoglyceride complexes. Journal of Cereal Science.

*Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

1985;**3**:239-248. DOI: 10.1016/ S0733-5210(85)80017-5

[27] Qin R, Yu J, Li Y, Copeland L, Wang S, Wang S. Structural changes of starch–lipid complexes during postprocessing and their effect on in vitro enzymatic digestibility. Journal of Agricultural and Food Chemistry. 2019;**67**(5):1530-1536. DOI: 10.1021/acs. jafc.8b06371

[28] Tufvesson F, Wahlgren M, Eliasson AC. Formation of amylose-lipid complexes and effects of temperature treatment. Part 2. Fatty acids. Starch-Starke. 2003;**55**(3-4):138-149. DOI: 10.1002/star.200390028

[29] Zheng M, Chao C, Yu J, Copeland L, Wang S, Wang S. Effects of chain length and degree of unsaturation of fatty acids on structure and in vitro digestibility of starch–protein–fatty acid complexes. Journal of Agricultural and Food Chemistry. 2018;**66**(8):1872-1880. DOI: 10.1111/ijfs.14347

[30] Kawai K, Takato S, Sasaki T, Kajiwara K. Complex formation, thermal properties, and in-vitro digestibility of gelatinized potato starch–fatty acid mixtures. Food Hydrocolloids. 2012;**27**:228-234. DOI: 10.1016/j. foodhyd.2011.07.003

[31] Meng S, Ma Y, Sun DW, Wang L, Liu T. Properties of starch-palmitic acid complexes prepared by high pressure homogenization. Journal of Cereal Science. 2014;**59**(1):25-32. DOI: 10.1016/j.jcs.2013.10.012

[32] Sun S, Jin Y, Hong Y, Gu Z, Cheng L, Li Z, et al. Effects of fatty acids with various chain lengths and degrees of unsaturation on the structure, physicochemical properties and digestibility of maize starch-fatty acid complexes. Food Hydrocolloids.

2021;**110**:106224. DOI: 10.1016/j. foodhyd.2020.106224

[33] Liu P, Gao W, Zhang X, Wu Z, Yu B, Cui B. Physicochemical properties of pea starch-lauric acid complex modified by maltogenic amylase and pullulanase. Carbohydrate Polymers. 2020; **242**:116332. DOI: 10.1016/j.carbpol. 2020.116332

[34] Cheng L, Feng T, Zhang B, Zhu X, Hamaker B, Zhang H, et al. A molecular dynamics simulation study on the conformational stability of amyloselinoleic acid complex in water. Carbohydrate Polymers. 2018;**196**:56-65. DOI: 10.1016/j.carbpol.2018.04.102

[35] Schahl A. Interactions polysaccharides-lipides: étude théorique et expérimentale combinant calculs de dynamique moléculaire, calculs quantiques de spectres RMN 13C et RMN 13C à l'état solide. Science des matériaux [cond-mat.mtrl-sci]. Français: Université Paul Sabatier - Toulouse III, 2020. ⟨NNT: 2020TOU30178⟩

[36] Lal MK, Singh B, Sharma S, Singh MP, Kumar A. Glycemic index of starchy crops and factors affecting its digestibility: A review. Trends in Food Science and Technology. 2021;**111**:741- 755. DOI: 10.1016/j.tifs.2021.02.067

[37] Svihus B, Uhlen AK, Harstad OM. Effect of starch granule structure, associated components and processing on nutritive value of cereal starch: A review. Animal Feed Science and Technology. 2005;**122**(3-4):303-320. DOI: 10.1016/j.anifeedsci.2005.02.025

[38] Hamaker BR, Bugusu BA. Overview: Sorghum proteins and food quality. Pretoria, South Africa. In: Workshop on the proteins of sorghum and millets: Enhancing nutritional and functional properties for Africa [Internet]. 2003.

Available from: http://www.afripro.org. uk/papers/Paper08Hamaker.pdf

[39] Rooney LW, Pflugfelder RL. Factors affecting starch digestibility with special emphasis on sorghum and corn. Journal of Animal Science. 1986;**63**(5):1607- 1623. DOI: 10.2527/jas1986.6351607x

[40] Annor GA, Marcone M, Bertoft E, Seetharaman K. In vitro starch digestibility and expected glycemic index of Kodo millet (*Paspalum scrobiculatum*) as affected by starch-protein-lipid interactions. Cereal Chemistry Journal. 2013;**90**:211-217. DOI: 10.1094/ CCHEM-06-12-0074-R

[41] Ren X, Chen J, Wang C, Molla MM, Diao X, Shen Q. In vitro starch digestibility, degree of gelatinization and estimated glycemic index of foxtail millet-derived products: Effect of freezing and frozen storage. Journal of Cereal Science. 2016;**69**:166-173. DOI: 10.1016/j.jcs.2016.03.007

[42] Granfeldt Y, Bjorck I. Glycemic response to starch in pasta: A study of mechanisms of limited enzyme availability. Journal of Cereal Science. 1991;**14**:47-61. DOI: 10.1016/S0733- 5210(09)80017-9

[43] Kim EHJ, Petrie JR, Motoi L, Morgenstern MP, Sutton KH, Mishra S, et al. Effect of structural and physicochemical characteristics of the protein matrix in pasta on in vitro starch digestibility. Food Biophysics. 2008;**3**:229-234. DOI: 10.1007/ s11483-008-9066-7

[44] Zou W, Sissons M, Warren FJ, Gidley MJ, Gilbert RG. Compact structure and proteins of pasta retard in vitro digestive evolution of branched starch molecular structure. Carbohydrate Polymers. 2016;**152**:441-449. DOI: 10.1016/j.carbpol.2016.06.016

[45] Jenkins DJ, Thorne MJ, Wolever TM, Jenkins AL, Rao AV, Thompson LU. The effect of starch-protein interaction in wheat on the glycemic response and rate of in vitro digestion. The American Journal of Clinical Nutrition. 1987; **45**:946-951. DOI: 10.1093/ajcn/ 45.5.946

[46] Lu X, Chang R, Lu H, Ma R, Qiu L, Tian Y. Effect of amino acids composing rice protein on rice starch digestibility. LWT. 2021;**146**:111417. DOI: 10.1016/j. lwt.2021.111417

[47] Zhu LJ, Liu QQ, Wilson JD, Gu MH, Shi YC. Digestibility and physicochemical properties of rice (*Oryza sativa* L.) flours and starches differing in amylose content. Carbohydrate Polymers. 2011;**86**(4): 1751-1759. DOI: 10.1016/j.carbpol. 2011.07.017

[48] Zarati M, Pirali M, Mirmiran P, Nouri N, Nakhoda K, Najafi H, et al. Glycemic index of various brands of rice in healthy individuals. International Journal of Endocrinology and Metabolism. 2008;**6**(4):200-204. Available from: https://www.sid.ir/en/ journal/ViewPaper.aspx?id=134381

[49] Parada J, Santos JL. Interactions between starch, lipids, and proteins in foods: Microstructure control for glycemic response modulation. Critical Reviews in Food Science and Nutrition. 2016;**56**(14):2362-2369. DOI: 10.1080/ 10408398.2013.840260

[50] Pasini G, Simonato B, Giannattasio M, Peruffo AD, Curioni A. Modifications of wheat flour proteins during in vitro digestion of bread dough, crumb, and crust: An electrophoretic and immunological study. Journal of Agricultural and Food Chemistry. 2001;**49**(5):2254-2261. DOI: 10.1021/ jf0014260

*Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

[51] Parada J, Aguilera JM. Microstructure, mechanical properties, and starch digestibility of a cooked dough made with potato starch and wheat gluten. LWT-Food Science and Technology. 2011;**44**(8):1739-1744. DOI: 10.1016/j.lwt.2011.03.012

[52] Chen X, He XW, Zhang B, Fu X, Jane JL, Huang Q. Effects of adding corn oil and soy protein to corn starch on the physicochemical and digestive properties of the starch. International Journal of Biological Macromolecules. 2017;**104**:481-486. DOI: 10.1016/j. ijbiomac.2017.06.024

[53] Xu H, Zhang G. Slow digestion property of microencapsulated normal corn starch. Journal of Cereal Science. 2014;**60**(1):99-104. DOI: 10.1016/j. jcs.2014.01.021

[54] Yang W, Hattori M, Kawaguchi T, Takahashi K. Properties of starches conjugated with lysine and poly(lysine) by the Maillard reaction. Journal of Agricultural and Food Chemistry. 1998;**46**(2):442-445. DOI: 10.1021/ jf970515i

[55] Miao M, Hamaker BR. Food matrix effects for modulating starch bioavailability. Annual Review of Food Science and Technology. 2021;**12**:169-191. DOI: 10.1146/annurev-food-070620- 013937

[56] Lal MK, Kumar A, Kumar A, Raigond P, Oko AO, Thakur N, et al. Dietary fibres in po66to. In: Potato. Singapore: Springer; 2020. pp. 37-50

[57] Xie F, Li M, Lan X, Zhang W, Gong S, Wu J, et al. Modification of dietary fibers from purple-fleshed potatoes (heimeiren) with high hydrostatic pressure and high pressure homogenization processing: A comparative study. Innovative Food

Science and Emerging Technologies. 2017;**42**:157-164. DOI: 10.1016/j. ifset.2017.05.012

[58] Krishnan S, Rosenberg L, Singer M, Hu FB, Djousse L, Cupples LA, et al. Glycemic index, glycemic load, and cereal fiber intake and risk of type 2 diabetes in US black women. Archives of Internal Medicine. 2007;**167**:2304-2309. DOI: 10.1001/archinte.167.21.2304

[59] Aldughpassi A, Abdel-Aal ESM, Wolever TM. Barley cultivar, kernel composition, and processing affect the glycemic index. The Journal of Nutrition. 2012;**142**:1666-1671. DOI: 10.3945/ jn.112.161372

[60] Ou S, Kwok KC, Li Y, Fu L. In vitro study of possible role of dietary fiber in lowering postprandial serum glucose. Journal of Agricultural and Food Chemistry. 2001;**49**(2):1026-1029. DOI: 10.1021/jf000574n

[61] Ahmed F, Sairam S, Urooj A. In vitro hypoglycemic effects of selected dietary fiber sources. Journal of Food Science and Technology. 2011;**48**:285-289. DOI: 10.1007/s13197-010-0153-7

[62] Vazquez-Gutierrez JL, Johansson D, Langton M. Effects of added inulin and wheat gluten on structure of rye porridge. LWT-Food Science and Technology. 2016;**66**:211-216. DOI: 10.1016/j.lwt.2015.10.034

[63] Singh J, Dartois A, Kaur L. Starch digestibility in food matrix: A review. Trends in Food Science and Technology. 2010;**21**(4):168-180. DOI: 10.1016/j. tifs.2009.12.001

[64] Regand A, Chowdhury Z, Tosh SM, Wolever TM, Wood P. The molecular weight, solubility and viscosity of oat beta-glucan affect human glycemic response by modifying starch

digestibility. Food Chemistry. 2011;**129**(2):297-304. DOI: 10.1016/j. foodchem.2011.04.053

[65] Zhang J, Luo K, Zhang G. Impact of native form oat β-glucan on starch digestion and postprandial glycemia. Journal of Cereal Science. 2017;**73**:84-90. DOI: 10.1016/j.jcs.2016.11.013

[66] Dhital S, Gidley MJ, Warren FJ. Inhibition of α-amylase activity by cellulose: Kinetic analysis and nutritional implications. Carbohydrate Polymers. 2015;**123**:305-312. DOI: 10.1016/j. carbpol.2015.01.039

[67] Bai Y, Wu P, Wang K, Li C, Li E, Gilbert RG. Effects of pectin on molecular structural changes in starch during digestion. Food Hydrocolloids. 2017;**69**:10-18. DOI: 10.1016/j.foodhyd. 2017.01.021

[68] Luo K, Zhang G. Nutritional property of starch in a whole-grain-like structural form. Journal of Cereal Science. 2018;**79**:113-117. DOI: 10.1016/j. jcs.2017.09.006

[69] Sciarini LS, Bustos MC, Vignola MB, Paesani C, Salinas CN, Perez GT. A study on fibre addition to gluten free bread: Its effects on bread quality and in vitro digestibility. Journal of Food Science and Technology. 2017;**54**(1):244-252. DOI: 10.1007/s13197-016-2456-9

[70] Sasaki T, Kohyama K. Effect of non-starch polysaccharides on the in vitro digestibility and rheological properties of rice starch gel. Food Chemistry. 2011;**127**(2):541-546. DOI: 10.1016/j.foodchem.2011.01.038

[71] Oh IK, Bae IY, Lee HG. Hypoglycemic effect of dry heat treated starch with xanthan: An in vitro and in vivo comparative study. Starch-Stärke. 2018;**70**(9-10):1800088. DOI: 10.1002/ star.201800088

[72] Cavallero A, Empilli S, Brighenti F, Stanca AM. High (1→3, 1→4)-β-glucan barley fractions in bread making and their effects on human glycemic response. Journal of Cereal Science. 2002;**36**:59-66. DOI: 10.1006/jcrs. 2002.0454

[73] Zhuang H, Chen Z, Feng T, Yang Y, Zhang J, Liu G, et al. Characterization of *Lentinus edodes* β-glucan influencing the in vitro starch digestibility of wheat starch gel. Food Chemistry. 2017;**224**:294-301. DOI: 10.1016/j. foodchem.2016.12.087

[74] Kang MJ, Bae IY, Lee HG. Rice noodle enriched with okara: Cooking property, texture, and in vitro starch digestibility. Food Bioscience. 2018;**22**:178-183. DOI: 10.1016/j.fbio.2018.02.008

[75] Ballance S, Knutsen SH, Fosvold W, Wickham M, Trenado CDT, Monro J. Glyceamic and insulinaemic response to mashed potato alone, or with broccoli, broccoli fibre or cellulose in healthy adults. European Journal of Nutrition. 2018;**57**:199-207. DOI: 10.1007/ s00394-016-1309-7

[76] Hardacre AK, Yap SY, Lentle RG, Monro JA. The effect of fibre and gelatinised starch type on amylolysis and apparent viscosity during in vitro digestion at a physiological shear rate. Carbohydrate Polymers. 2015;**123**:80-88. DOI: 10.1016/j.carbpol.2015.01.013

[77] Gelencser T, Gal V, Salgo A. Effects of applied process on the in vitro digestibility and resistant starch content of pasta products. Food and Bioprocess Technology. 2010;**3**:491-497. DOI: 10.1007/s11947-008-0105-7

[78] Li Y, Lv J, Wang L, Zhu Y, Shen R. Effects of millet bran dietary fiber and millet flour on dough development, steamed bread quality, and digestion in *Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

vitro. Applied Sciences. 2020;**10**:912. DOI: 10.3390/app10030912

[79] Mkandawire NL, Kaufman RC, Bean SR, Weller CL, Jackson DS, Rose DJ. Effects of sorghum (*Sorghum bicolor* (L.) Moench) tannins on α-amylase activity and in vitro digestibility of starch in raw and processed flours. Journal of Agricultural and Food Chemistry. 2013;**61**(18):4448-4454. DOI: 10.1021/ jf400464j

[80] Isken F, Klaus S, Osterhoff M, Pfeiffer AF, Weickert MO. Effects of long-term soluble vs. insoluble dietary fiber intake on high-fat diet-induced obesity in C57BL/6J mice. The Journal of Nutritional Biochemistry. 2010;**21**:278- 284. DOI: 10.1016/j.jnutbio.2008.12.012

[81] Weickert MO, Mohlig M, Koebnick C, Holst JJ, Namsolleck P, Ristow M, et al. Impact of cereal fibre on glucose regulating factors. Diabetologia. 2005;**48**(11):2343-2353. DOI: 10.1007/ s00125-005-1941-x

[82] Zheng J, Shen N, Wang S, Zhao G. Oat beta-glucan ameliorates insulin resistance in mice fed on high-fat and high-fructose diet. Food and Nutrition Research. 2013;**57**(1):22754. DOI: 10.3402/fnr.v57i0.22754

[83] Choi JS, Kim H, Jung MH, Hong S, Song J. Consumption of barley β-glucan ameliorates fatty liver and insulin resistance in mice fed a high-fat diet. Molecular Nutrition and Food Research. 2010;**54**:1004-1013. DOI: 10.1002/ mnfr.200900127

[84] Dong J, Cai F, Shen R, Liu Y. Hypoglycaemic effects and inhibitory effects on intestinal disaccharidases of oat beta-glucan in streptozotocininduced diabetic mice. Food Chemistry. 2011;**129**:1066-1071. DOI: 10.1016/j. foodchem.2011.05.076

[85] Liu M, Zhang Y, Zhang H, Hu B, Wang L, Qian H, et al. The anti-diabetic activity of oat β-d-glucan in streptozotocin–nicotinamide induced diabetic mice. International Journal of Biological Macromolecules. 2016; **91**:1170-1176. DOI: 10.1016/j.ijbiomac. 2016.06.083

[86] Raza H, Ameer K, Ren X, Liang Q, Chen X, Chen H, et al. Physicochemical properties and digestion mechanism of starch-linoleic acid complex induced by multi-frequency power ultrasound. Food Chemistry. 2021;**364**:130392. DOI: 10.1016/j.foodchem.2021.130392

[87] Guo T, Hou H, Liu Y, Chen L, Zheng B. In vitro digestibility and structural control of rice starchunsaturated fatty acid complexes by high-pressure homogenization. Carbohydrate Polymers. 2021;**256**:117607. DOI: 10.1016/j.carbpol.2020.117607

[88] Luo S, Zeng Z, Mei Y, Huang K, Wu J, Liu C, et al. Improving ordered arrangement of the short-chain amyloselipid complex by narrowing molecular weight distribution of short-chain amylose. Carbohydrate Polymers. 2020;**240**:116359. DOI: 10.1016/j. carbpol.2020.116359

[89] He H, Zheng B, Wang H, Li X, Chen L. Insights into the multi-scale structure and in vitro digestibility changes of rice starch-oleic acid/linoleic acid complex induced by heat-moisture treatment. Food Research International. 2020;**137**:109612. DOI: 10.1016/j. foodres.2020.109612

[90] Chao C, Huang S, Yu J, Copeland L, Wang S, Wang S. Molecular mechanisms underlying the formation of starch-lipid complexes during simulated food processing: A dynamic structural analysis. Carbohydrate Polymers. 2020;**244**:116464. DOI: 10.1016/j.carbpol.2020.116464

[91] Zheng B, Wang T, Wang H, Chen L, Zhou Z. Studies on nutritional intervention of rice starch-oleic acid complex (resistant starch type V) in rats fed by high-fat diet. Carbohydrate Polymers. 2020;**246**:116637. DOI: 10.1016/j.carbpol.2020.116637

[92] Handarini K, SaumanHamdani J, Cahyana Y, SitiSetiasih I. Functional and pasting properties of a starch–lipid complex formed with gaseous ozone and palm oil. International Journal of Food Properties. 2020;**23**(1):1361-1372. DOI: 10.1080/10942912.2020.1801723

[93] Kang X, Yu B, Zhang H, Sui J, Guo L, Abd El-Aty AM, et al. The formation and in vitro enzymatic digestibility of starch-lipid complexes in steamed bread free from and supplemented with different fatty acids: Effect on textural and retrogradation properties during storage. International Journal of Biological Macromolecules. 2021;**166**:1210-1219. DOI: 10.1016/j. ijbiomac.2020.11.003

[94] Krolikowska K, Pietrzyk S, Labanowska M, Kurdziel M, Pajak P. The influence of acid hydrolysis on physicochemical properties of starcholeic acid mixtures and generation of radicals. Food Hydrocolloids. 2021;**118**:106780. DOI: 10.1016/j. foodhyd.2021.106780

[95] Cui J, Zheng B, Liu Y, Chen L, Li B, Li L. Insights into the effect of structural alternations on the digestibility of rice starch-fatty acid complexes prepared by high-pressure homogenization. LWT. 2021;**136**:110294. DOI: 10.1016/j. lwt.2020.110294

[96] Gallegos-Infante JA, Bello-Perez LA, Rocha-Guzman NE, Gonzalez-Laredo RF, Avila-Ontiveros M. Effect of the addition of common bean (*Phaseolus vulgaris* L.) flour on the in

vitro digestibility of starch and undigestible carbohydrates in spaghetti. Journal of Food Science. 2010;**75**(5): H151-H156. DOI: 10.1111/j.1750-3841. 2010.01621.x

[97] Aravind N, Sissons M, Fellows C. Can variation in durum wheat pasta protein and starch composition affect in vitro starch hydrolysis? Food Chemistry. 2011;**124**(3):816-821. DOI: 10.1016/j. foodchem.2010.07.002

[98] Kumar SB, Prabhasankar P. A study on starch profile of rajma bean (*Phaseolus vulgaris*) incorporated noodle dough and its functional characteristics. Food Chemistry. 2015;**180**:124-132. DOI: 10.1016/j.foodchem.2015.02.030

[99] Giuberti G, Gallo A, Cerioli C, Fortunati P, Masoero F. Cooking quality and starch digestibility of gluten free pasta using new bean flour. Food Chemistry. 2015;**175**:43-49. DOI: 10.1016/j.foodchem.2014.11.127

[100] Giuberti G, Rocchetti G, Sigolo S, Fortunati P, Lucini L, Gallo A. Exploitation of alfalfa seed (*Medicago sativa* L.) flour into gluten-free rice cookies: Nutritional, antioxidant and quality characteristics. Food Chemistry. 2018;**239**:679-687. DOI: 10.1016/j. foodchem.2017.07.004

[101] Xie F, Huang Q, Fang F, Chen S, Wang Z, Wang K, et al. Effects of tea polyphenols and gluten addition on in vitro wheat starch digestion properties. International Journal of Biological Macromolecules. 2019;**126**:525-530. DOI: 10.1016/j.ijbiomac.2018.12.224

[102] Yang Y, Wang L, Li Y, Qian HF, Zhang H, Wu GC, et al. Investigation the molecular degradation, starch-lipid complexes formation and pasting properties of wheat starch in instant noodles during deep-frying treatment.

*Binary Interactions and Starch Bioavailability: Critical in Limiting Glycemic Response DOI: http://dx.doi.org/10.5772/intechopen.101833*

Food Chemistry. 2019;**283**:287-293. DOI: 10.1016/j.foodchem.2019.01.034

[103] Khatun A. The impact of rice protein and lipid on in vitro rice starch digestibility [Doctoral dissertation]. East Lismore: Southern Cross University; 2019

[104] Chen X, Luo J, Fu L, Cai D, Lu X, Liang Z, et al. Structural, physicochemical, and digestibility properties of starch-soybean peptide complex subjected to heat moisture treatment. Food Chemistry. 2019;**297**:124957. DOI: 10.1016/j. foodchem.2019.124957

[105] Sofi SA, Singh J, Chhikara N, Panghal A. Effect of incorporation of germinated flour and protein isolate from chickpea on different quality characteristics of rice-based noodle. Cereal Chemistry. 2020;**97**(1):85-94. DOI: 10.1002/cche.10192

[106] Gelencser T, Gal V, Hodsagi M, Salgo A. Evaluation of quality and digestibility characteristics of resistant starch-enriched pasta. Food and Bioprocess Technology. 2008;**1**(2):171- 179. DOI: 10.1007/s11947-007-0040-z

[107] Capriles VD, Arêas JA. Effects of prebiotic inulin-type fructans on structure, quality, sensory acceptance and glycemic response of gluten-free breads. Food and Function. 2013;**4**:104- 110. DOI: 10.1039/C2FO10283H

[108] Bustos MC, Perez GT, Leon AE. Sensory and nutritional attributes of fibre-enriched pasta. LWT-Food Science and Technology. 2011;**44**:1429-1434. DOI: 10.1016/j.lwt.2011.02.002

[109] Giuberti G, Fortunati P, Gallo A. Can different types of resistant starch influence the in vitro starch digestion of gluten free breads? Journal of Cereal Science. 2016;**70**:253-255. DOI: 10.1016/j. jcs.2016.07.001

## Resistant Starch: A Promising Functional Food Ingredient

*Revati Wanikar and Swati Kotwal*

#### **Abstract**

Nowadays dietary starches are considered as a tool for maintaining good health. Recently resistant starch has received much attention because of its specific contribution to human health. Resistant starch escapes digestion in the small intestine and fermented in the colon by colonic microorganisms. Resistant starch has wide applications in varieties of food products. In the present study, types of resistant starch, their sources, physiological benefits, have been discussed briefly. This chapter focuses on factors affecting starch digestion, resistant starch content, characterization of resistant starch and various techniques employed to study their structural features.

**Keywords:** resistant starch, starch digestion, glycemic index, short chain fatty acids, molecular characterization, SEM

#### **1. Introduction**

The concept of resistant starch (RS) has raised interest as a source of dietary fiber. A recent recognition of resistant starch as a functional food ingredient finds application in varieties of food products. The term "Resistant Starch" was first coined by Englyst et al. in 1982 [1] and later defined formally by European Flair Concerted Action on Resistant Starch (EURESTA) as "a fraction of starch that resists digestion in the small intestine of healthy individual and passes to the large intestine where it is a substrate for bacterial fermentation" [2].

RS has potential health benefits similar to soluble fiber. The content of resistant starch in foods has considerable importance because it positively influences functioning of digestive tract, gut microflora, glycemic index, maintain blood cholesterol level and assist in the control of diabetes. These qualities of RS are attracting the attention of food industries and to understand its formation and ways to modulate its content according to the need of the human ailment [3].

History of starch and its usage by man has been extensively studied and are well documented over the years. Starch is the most significant form of carbohydrate in terms of its universality as an energy source in human diet and its applicability in varieties of food products. The understanding that starch is not completely digested and the finding that some starches are poorly digested has led to improved interest for nutritionist. Starch digestion, its impact on glucose release and its relevance to diabetes, obesity and other metabolic disorders resulted in renewed interest in intake of starchy foods. Starchy foods which release glucose slowly and over a longer period

of time after digestion are of great interest. Controlling glucose release from starchy foods has become challenge for food developers in the context of worldwide health concern. It is possible to modify the structure of starch for desired functional properties by applying various food processing [4–9].

Starch is utilized in several industrial applications due to its ability to impart broad range of functional properties to food and non food products. The new insights have increased the interest in identifying new sources of starches with distinct functional properties and their potential for processing at large scale [10, 11].

Starch is the only natural polysaccharide digested by enzymes of human gastrointestinal tract. Starch digestion starts in mouth where α-amylase in saliva breaks down starch into oligosaccharides and maltose. The bolus is then transported to the stomach where the enzyme activity is inhibited due to low pH and therefore starch does not break down until reaches to the small intestine. By the action of pancreatic α-amylase in the small intestine starch is broken down to glucose and maltose however all the starch is not hydrolysed and absorbed. Fraction of starch which escapes digestion is passed into the large intestine and fermented by intestinal microflora. Hydrolysis of starch by enzymatic digestion may be affected by digestion conditions, granule size, amylose/ amylopectin ratio and processing method of starch [12]. Starch is normally processed or cooked before being consumed by humans; hence extent of disruption of starch structure determines its susceptibility to enzymatic digestion [13].

According to in vitro digestion, starch is classified into three categories


#### **2. Types of resistant starch**

Depending on its resistance to digestion, RS is classified as RS1, RS2, RS3 and RS4 (**Table 1**).

**RS1** is a physically protected starch surrounded by cell wall and other food matrix which hinders the digestibility of starch. RS1 is found in whole or partially milled seeds, cereal grains or legumes. Human gastrointestinal tract lacks the enzymes need to degrade


#### **Table 1.**

*Types of resistant starch.*

cellulose, hemicelluloses, lignin and other plant cell wall constituents and therefore this form of physically protected starch passes to the small intestine in intact form [18].

**RS2** is a starch in a certain granular form and they are protected from digestive enzymes due to their crystalline structure. Such type of starch is mostly present in uncooked potatoes and bananas. Raw potato starch has large granule size and hence limited access to the enzymatic attack [18, 19]. The extent of starch hydrolysis is determined by the structure and size of the starch granule surface. However, No relationship has been reported between the extent of starch hydrolysis and degree of enzyme adsorption on the surface of the starch granule. Potato starches have B type crystalline pattern whereas cereal starches are characterized by A type with higher degree of crystallinity and therefore susceptible to enzymatic attack compared to potato starch. Waxy maize starch which contains 100% amylopectin with 40% crystallinity is more susceptible to digestion than high amylose maize starch with 15% crystallinity [20]. Crystallinity plays an important role in the architecture of the granules in terms of its susceptibility to enzymatic hydrolysis.

**RS3** is a retrograded starch. Retrogradation occurs when starchy foods are gelatinized and cooled. Gelatinization is a process in which starch is heated in presence of water which resulted in swelling of the granule, leaching of amylose and loss of crystalline structure. Gelatinization is a complex process which starts at low temperature by swelling and continues until the granules are disrupted completely. As the temperature increases the interaction between the polymers decrease and starch granule breaks down. These structural changes take place during heating of starch in the presence of water. Extent of starch gelatinization depends on many factors such as botanical source of starch, heating rate, water content, amylose-amylopectin ratio, and processes applied to starch before gelatinization [21, 22]. Retrogradation is a process in which gelatinized starch upon cooling tends to reassociate to form more ordered structure. This re-annealing of amylose and amylopectin branches occur when gelatinized starch is stored at lower temperatures for longer period of time and thus protects from enzymatic attack [23]. Retrogradation is a property of starch, which is of particular interest in terms of nutritional significance and digestibility. Starch retrogradation was initially thought to be undesirable because of its staling effect on bread and other starchy foods, affecting shelf life and consumer acceptance. However, intensive research on retrogradation of starch over the years have shown

that it is desirable in some applications such as preparation of breakfast cereals, parboiled rice, mashed potatoes, chinese rice, because of the changes in structural, sensory and mechanical properties [23]. The most important and significant property of retrograded starch is its slow releaseof glucose into the bloodstream [22, 24]. Retrogradation of starch is associated with series of physical changessuch as increase in viscosity, gel formation, increased degree of crystallinity with the formation of B type crystalline pattern [22]. It is an ongoing process in unstable gelatinized starch, due to rapid recrystallization in amylose polymers followed by slow recrystallization of amylopectin molecules [25].

**RS4** is a chemically modified starch formed by cross linking or by adding chemical derivatives.

Recently, two components have been proposed as RS5. The first component is amylose-lipid-complex and second component is resistant maltodextrins [17, 26]. RS occurs naturally in all starchy foods and can be developed in others by combination of several processing conditions.

#### **3. Sources of resistant starch**

High amount of resistant starch is found in raw potato and unripe banana. Several studies conferred the beneficial effects of unripe banana on human health which is associated with its high RS content. Raw potato starch has the highest RS content (75%). Whole grains are rich sources of dietary fiber and resistant starch. **Table 2** provides RS content of some basic foods [27].


#### **Table 2.**

*RS content of some basic foods (g/100 g).*

#### **4. Nutritional and health impact of resistant starch**

#### **4.1 RS as a prebiotic agent**

'Prebiotics' are food ingredients that help support growth of probiotic bacteria. Prebiotics are considered as nondigestible carbohydrates such as resistant starch

which ferment in the colon by gut microflora. Essentially they stimulate activity of good bacteria such as *Lactobacilli, Bifidobacteria* and *Staphylococci* and confer benefits upon host health [22].

#### **4.2 Prevention of colon cancer**

Resistant starch escapes digestion in the small intestine and is fermented in the large intestine resulting in the production of short chain fatty acids (SCFA), some gases like methane, hydrogen and carbon dioxide and organic acid (e.g. lactic acid) [28]. SCFAinclude acetate, propionate and butyrate. A number of studies have indicated the benefits of resistant starch as it produces SCFA, as compared to dietary fiber, especially butyrate production is more. Butyrate is the main energy substrate for colonocytes and several in vitro studies have shown that butyrate inhibits malignant transformation of cells by arresting one of the phases of cell cycle (G1) [23, 25]. More butyrate production is associated with lower incidence of colon cancer [29, 30]. **Table 3** presents data on SCFA produced by the fermentation of some foods in the large intestine.

#### **4.3 Hypoglycaemic effects**

Foods containing high resistant starch reduce the rate of digestion. Slow rate of digestion has implications for the use of RS in controlled glucose release applications. Starch digestion and concurrent changes in blood glucose levels are largely dependent on its rate of hydrolysis by α-amylase and extent of digestion. From the health point of view, the starches that are less susceptible to α-amylase attack score high as they bring about less change in post prandial glucose level and more starch enters the colon undigested.RS consumption is associated with reduced post prandial glycemic and insulinemic response. Therefore RS can help in the treatment of diabetes, obesity and in weight management [30].

#### **4.4 Hypocholesterolemic effects**

Based on the studies in rats, RS is shown to affect lipid metabolism where reductions in measures of lipid metabolism is observed (total lipids, total cholesterol, LDL, HDL, VLDL) [30].


#### **Table 3.**

*Percentage of total SCFA produced by various substrates.*

#### **4.5 Inhibition of fat accumulation**

Various studies examined that high RS meals may increase the use of fat stores as a result of reduction in insulin secretions. High RS meals imparted less satiety than low RS meals whereas in another study on human volunteers, high RS meal caused greater satiety [32]. Keenan et.al reported in their study that incorporating RS in diet may increase the gut hormones that are effective in reducing energy intake. This may be an effective approach for the treatment of obesity [33].

#### **4.6 RS as a functional ingredient**

The functional properties of resistant starch such as swelling, viscosity, gel consistency, water holding capacity make it useful in variety of food applications. Low water holding capacity of RS makes it a functional ingredient which provides good handling in processing, crispness, expansion and improved texture of food products [14, 19]. Hi-maize is the first commercial RS introduced in the market in 1993 in Australia. The other sources of commercial RS 3 are CrystaLean, Novelose and Actistar which are highly retrograded starches. Fibersym is a chemically modified RS 4 product [14]. RS may find applications in varieties of food products such as bakery products [34, 35], pastas and puddings [14, 36, 37], yoghurt, cheese, icecreams [19, 38, 39]. RS incorporated biscuits has been investigated and reported that incorporating RS in foods have potential to develop fiber rich products without changing their general properties. RS can also be used as thickening agent and substituted fat in imitation cheese and many other products where insoluble fiber is desirable conferring the benefits of RS as a functional fiber. Bread and pasta are the most widely consumed starch based products. RS as a food ingredient is increasingly important as resistant starch has low calorific value (8 kJ/g) compared to fully digestible starch (15 kJ/g) [18].

#### **5. Factors affecting starch digestibility and resistant starch content**

The structural changes of starch during processing are the major determinants of starch functional properties for food processing, during digestion and in industrial applications [25, 40]. Wide range of techniques has been used for processing the food materials which involve chemical and hydrothermal treatments. The processing methods are reported to influence the nutritional characteristics of foods. Roasting and cooking without pressure are some of the major processes used in household whereas domestic storage is also a widely used method now-a-days. Processing methods are the major determinants of starch digestibility and amount of starches reaching the colon [41]. Gelatinization and retrogradation are important properties of starch that determine its functionality, quality, acceptability and nutritional value [22]. Several inherent properties of starch influence the formation of RS and starch digestibility are discussed below.

#### **5.1 Granule morphology**

Size and shape of starch granule is influenced by botanical origin. Several studies have indicated negative relationship between large granule size of wheat, barley, and potato and starch digestibility. The rate of starch hydrolysis is increased by decreasing the size of the granule. This was observed among starches with different botanical origin [15]. Smaller granules have the higher susceptibility to enzyme binding [42].

#### **5.2 Surface of granules**

Starch hydrolysis is also dependent on the shape of the granules which varies from spherical to polyhedral. The molecular association of starch granules may reduce the binding of amylase to granule surface [43].

The surface characteristics such as pin holes, equatorial grooves, indentations and small nodules have an impact on starch digestibility [12] smooth surface of potato and high amylose starches with few pits and pores explain the starch resistance to amylases [42, 43].

#### **5.3 Molecular structure and crystallinity**

The different crystalline patterns of starches such as A, B and C differ in their packing of double helical structures of amylopectin molecules thereby influencing their hydrolysis [44] It is reported that B type crystalline starches are more resistant to amylolytic attack than A type. Amylase attack also depends on linear chain length of amylopectin molecule which forms the helices. The longer chains are more resistant to enzymatic hydrolysis due to more stable helices [12, 15]. The hydrolysis starts earlier in the amorphous region of C type crystalline starches. Additionally, the crystalline distribution in granules has an impact on digestibility. Higher resistance was observed in starches with higher amount of double helices. This may be attributed to the resistance of high amylose native starches, which are less crystalline than native starches with high crystallinity.

#### **5.4 Amylose amylopectin ratio**

There is a positive correlation between amylose content and resistant starch formation. The linear amylose chains are bound to each other by hydrogen bonds which make them less accessible to hydrolysis [12]. The high proportion of amylopectin molecule in starch granule makes the larger surface area and therefore a molecule becomes more accessible to amylolytic attack. Starch gelatinization is difficult in high amylose starches and is more susceptible to retrogradation [36]. The *in vitro* and *in vivo* starch digestibility of high amylose starches were reported to be lower than normal starches [45].

#### **5.5 Interaction of starch with other components**

Food matrixes such as proteins and lipids play significant role during processing and affect the starch digestibility.

#### *5.5.1 Lipids*

Lipids are associated with starch granules. The free fatty acids and phospholipids are complexed with amylose and make the starch resistant to digestion. The lipids are usually present on the surface of the granules and reduce the binding of enzymes. The enzymatic digestibility is also reduced by addition of lauric, palmitic and oleic acid [43, 46].

#### *5.5.2 Proteins*

The surface proteins influences enzyme binding and limit the rate of hydrolysis. The starch from pulses is hard to digest due to interaction with proteins and presence of protective network around the granule [12].

#### *5.5.3 Dietary fiber*

Gaur and xanthan gums are some of the dietary fibers which affect the digestibility due to their high viscosity which slows down the movement and absorption of digestion products in the small intestine [14].

#### *5.5.4 Ions*

Phosphorous as phosphate monoesters and phospholipids significantly affect the starch properties. The tendency of phospholipids to form complexes with amylose and amylopectin makes the starch less susceptible to enzyme hydrolysis. Calcium and potassium ions reported to decrease RS yield [47].

#### **6. Techniques used to study morphological, molecular and thermal characteristics of resistant starch**

Understanding the molecular characteristics of starches to study the functional behavior and their suitability and applicability in various food industries is of great importance.

**Thermal property** is an important functional property of starch that varies with respect to the macromolecular composition (amylose and amylopectin ratio), double helical structure of amylopectin (chain length, branching, and degree of polymerization) and granule architecture (amorphous to crystalline ratio), granule morphology and size distribution. Differential scanning calorimetry (DSC) is the widely used technique to study thermal behavior of starches as well as other polymers. DSC can characterize modifications in starches, high amylose starches and waxy maize starches as well [48].

**Spectroscopic techniques** can provide appropriate information about the native as well as modified starches and their structural features. It also provides information of structural changes during gelatinisation and retrogradation.

The infrared (IR) spectroscopy can detect the molecular bond vibrations (especially C▬O and C▬C bonds) which yield both qualitative and quantitative information, such as that on the amorphous and crystalline regions of the starch granule [49]. Using FT-IR technique it was also observed that the high amylose maize and potato starches (RS2) exhibited greater level of ordered structure in the external region than wheat, maize or waxy maize starches. Due to retrogradation during storage, conformational changes in starches can be monitored and the intensity changes of conformational-sensitive bands in the 1300–800 cm−1 region could be observed [23].

**Scanning electron microscopy** technique is generally used to provide topographic features of RS. Differences in granule morphologyof starches can also be detected using SEM [48, 50]. SEM images of native versus resistant starches formed from different processing techniques are shown in **Figure 1**. Pinholes on the surface of the starch granules were observed in native starches isolated from millets. RS from cooked samples showed irregular and uneven surface zone. RS from retrograded starches showed fibrous, compact and less smooth structures [51].

*Resistant Starch: A Promising Functional Food Ingredient DOI: http://dx.doi.org/10.5772/intechopen.101558*

#### **Figure 1.**

*SEM image of native versus resistant starches. Note: (A) TS native, (B) RS native, (C) TS roasted, (D) RS roasted, (E) TS cooked, (F) RS cooked, (G) TS cooked and stored at* −*20°C for 30 days, (H) RS cooked and stored at* −*20°C for 30 days. TS: total starch; and RS: resistant starch. Source: R. Wanikar [51].*

**X-ray diffraction** can be applied to investigate different pattern of crystalline Structure and crystallinity of starch obtained from various botanical sources. XRD generally detects the regularly repeating ordering of helices and thereby reflecting the three-dimensional order of crystalline structure of starch [52].

There is an increased awareness in consumers for health and diet which has led enormous research on resistant starch, its content in foods and structural characterization. When combined the information generated from the above techniques can provide comprehensive analysis of structural characteristics of resistant starch, as well as changes occur during the formation of RS when compared with the structure of their native starches.

### **7. Conclusion**

Resistant starch is not accessible to digestive enzymes. This undigested starch fraction is of particular significance to human health as it lowers the calorific value of food and therefore provides a means to use as a potential food ingredient. The content of resistant starch can be increased by various food processing. Consumer's awareness about health and food is one of the reasons for increased popularity of extensive research on resistant starch and their health impact. Structural characterization of RS by using different techniques and their relationship needs a deeper understanding. Further studies are needed to clarify the relationship between physiological effects and molecular characterization of RS. In vitro RS fermentation and colon cancer incidence is an important aspect for further study.

### **Author details**

Revati Wanikar1 \* and Swati Kotwal<sup>2</sup>

1 Department of Biotechnology, Dr. D.Y.Patil ACS College, Savitribai Phule Pune University, Pimpri, Pune, India

2 Department of Biochemistry, RTM Nagpur University, Nagpur, India

\*Address all correspondence to: wanikarrevati@gmail.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Englyst HN, Kingman S, Cummings J. Classification and measurement of nutritionally important starch fractions. European Journal of Clinical Nutrition. 1992;**46**:S33-S50

[2] Englyst HN, Cummings JH. Resistant starch, a new food component: classification of starch for nutritional purposes. In: Morton ID, editor. Cereals in a European Context. First European Conference on Food Science and Technology. Chichester: EllisHorwood; 1987. pp. 221-233

[3] Annison G, Topping DL. Nutritional role of resistant starch: chemical structure vs physiological function. Annual Reviews in Nutrition. 1994;**14**:297-320

[4] Eliasson A-C. Starch in Food, Structure, Function and Application. USA: Woodhead Publishing Limited, CRC Press; 2004. Available from: www. woodhead-publishing.com

[5] Vinoy S et al. Slow release carbohydrates: Growing evidence on metabolic responces and public health interest. Food Nutrition Research. 2016;**60**:31662

[6] Taylor JRN et al. Developments in modulating glycemic response in starchy cereal foods. Starch/Staerke. 2015; **67**(1-2):79-89

[7] Alay SCA et al. Physiological properties, modifications and applications of starches from different botanical sources. Food Science and Technology. 2015;**35**(2):215-236

[8] Tharanathan RN. Starch—Value addition by modification. Critical Reviews in Food Science and Nutrition. 2005;**45**:371-384

[9] Park SH et al. Properties and applications of starch modifying enzymes for use in the banking industry. Food Science and Biotechnology. 2018;**27**(2):299-312

[10] Ádina L, Santana M, Meireles AA. New starches are the trend for industry applications: A review. Food and Public Health. 2014;**4**(5):229-241

[11] SubaricaAckar D, Jurislav Babic BM. Medicinski Glasnik. Starch for Health. 2011;**9**:17-22

[12] Singh J et al. Starch digestion in food matrix. Trends in Food Science and Technology. 2010;**21**:168-180

[13] Wang TL, Bogracheva TY, Hedley CL. Starch: as simple as A, B, C? Journal of Experimental Botany. 1998;**49**(320):481-502

[14] Sajilata MG, Singhal RS, Kulkarni PR. Resistant starch—A review. Comprehensive Reviews in Food Science and Food Safety. 2006;**5**(1):1-17

[15] Lehmann U, Robin F. slowly digestible starch—Its structure and health implications: a review. Trends in Food Science & Technology. 2007;**18**(7): 346-355

[16] Dona AC, Pages G, Gilbert RG, Kuchel PW, et al. Digestion of starch: In vivo and in vitro kinetic models used to characterise oligosaccharide or glucose release—Review. Carbohydrate Polymers. 2010;**80**:599-617

[17] Nugent AP. Health properties of resistant starch. Nutrition Bulletin. 2005;**30**(1):27-54

[18] Leszczyñski W. Resistant starch– classification, structure, production. Polish Journal of Food and Nutrition Sciences. 2004;**13**(54):37-50

[19] Fuentes-Zaragoza E, Sánchez-Zapata E, Sendra E, Sayas E, Navarro C, Fernández-López J, et al. Resistant starch as prebiotic: A review. Starch-Stärke. 2011;**63**(7):406-415

[20] Brown I. Complex carbohydrates and resistant starch. Nutrition Reviews. 1996;**1996**(54):S115-S119

[21] Ring et al. Some studies on starch gelation. Starch-Strake. 1985;**37**: 8083

[22] Wang S, Copeland L. Molecular disassembly of starch granules. Food & Function. 2013;**4**:1564

[23] Karim AA, Norziah MH, Seow CC. Methods for the study of starch retrogradation. Food Chemistry. 2000;**71**:9-36

[24] Haralampu S. Resistant starch-a review of the physical properties and biological impact of RS 3. Carbohydrate Polymers. 2000;**41**(3):285-292

[25] Wang S et al. Starch retrogradation: A comprehensive review. Comprehensive Reviews in Food Science and Food Safety. 2015;**14**:568-585

[26] Lockyer S, Nugent AP. Health effects of resistant starch. Nutrition Bulletin. 2017;**42**(1):10-41

[27] Lunn J, Buttriss JL. Carbohydrates and dietary fibre. Nutrition Bulletin. 2007;**32**:21-64

[28] Cummings JH, Beatty ER, Kingman SM, Bingham SA, Englyst HN, et al. Digestion and physiological properties of resistant starch in human large bowel. British Journal of Nutrition. 1996;**75**(5):733-747

[29] Cassidy A, Bingham SA, Cummings JH. Starch intake and colorectal cancer risk: an international comparison. British Journal of Cancer. 1994;**69**:937-942

[30] Birt DF, Boylston T, Hendrich S. Resistant starch: promise for improving human health. Advances in Nutrition. 2013;**6**:587-601

[31] Sharma A, Yadav BS, Ritika BY. Resistant starch: Physiological roles and food applications. Food Reviews International. 2008;**24**:193-234

[32] Anderson GH, Catherine NL, Woodened DM. Inverse association between the effect of carbohydrates on blood glucose and subsequent short term food intake in young men. American Journal of Clinical Nutrition. 2002;**76**: 1023-1030

[33] Keenan MJ, Zhou J. Effect of resistant starch, a non digestible fermentable fiber, on reducing body fat. Obesity. 2006;**14**:1523-1534

[34] Korus J, Witczak M, Ziobro R, Juszczak L. The impact of resistant starch on characteristics of gluten-free dough and bread. Food Hydrocolloids. 2009;**23**(3):988-995

[35] Sanz-Penella JM, Wronkowska M, Smietana MS, Collar C, Haros M. Impact of the addition of resistant starch from modified pea starch on dough and bread performance. European Food Research and Technology. 2010;**231**:499-508

[36] Gelencsér T, Juhász R, Hódsági M, Gergely S, Salgó A. Comparative study of native and resistant starches. Acta Alimentaria. 2008;**37**(2):255-270

[37] Ares G, Baixauli R, Sanz T, Varela P, Salvador A. New functional fibre in milk puddings: Effect on sensory properties

*Resistant Starch: A Promising Functional Food Ingredient DOI: http://dx.doi.org/10.5772/intechopen.101558*

and consumers acceptability. LWT - Food Science and Technology. 2009;**42**:710-716

[38] Homayouni A, Azizi A, Ehsani MR, Yarmand MS, Razavi SH. Effect of microencapsulation and resistant starch on the probiotic survival and sensory properties of synbiotic ice cream. Food Chemistry. 2008;**111**:50-55

[39] Arimi JM, Duggan E, O'Riordan ED, O'Sullivan M, Lyng JG. Microwave expansion of imitation cheese containing resistant starch. Journal of Food Engineering. 2008;**88**:254-262

[40] Englyst KN, Hudson GJ, Englyst HN. Starch analysis in food. In: Encyclopedia of Analytical Chemistry. Englyst Carbohydrate services, Eastleigh, UK: Wiley online library; 2000. pp. 1-19

[41] Muir JG, Birkett A, Brown I, Jones G, O'Dea K. Food processing and maize variety affects amounts of starch escaping digestion in the small intestine. The American Journal of Clinical Nutrition. 1995;**61**:82-89

[42] Tester RF, Qi X, Karkalas J. Hydrolysis of native starches with amylases. Animal Feed Science and Technology. 2006;**130**:39-54

[43] Tester RF, Karkalas J, Qi X. Starch— Composition, fine structure and architecture—Review. Journal of Cereal Science. 2004;**39**(2):151-165

[44] Li L, Jiang H, Campbell M, Blanco M, Jane J. Characterization of maize amylose-extender (ae) mutant starches, Part I: Relationship between resistant starch contents and molecular structures. Carbohydrate Polymers. 2008;**74**(3):396-404

[45] Topping DL, Clifton PM. Short-chain fatty acids and human colonic function: Roles of resistant starch and non-starch

polysaccharides. Physiological Reviews. 2001;**81**:1031-1064

[46] Svihus B, Uhlen AK, Harstad OM. Effect of starch granule structure, associated components and processing on nutritive value of cereal starch: A review. Animal Feed Science and Technology. 2005;**122**:303-320

[47] Escarpa A, Gonzalez MC, Morales MD, Saura-Calixto F, et al. An approach to the influence of nutrients and other food constituents on resistant starch formation. Food Chemistry. 1997;**60**(4):527-532

[48] Singh J, Singh N. Studies on the morphological, thermal and rheological properties of starch separated from some Indian potato cultivars. Food Chemistry. 2001;**75**:67-77

[49] Millan-Testa CE, Mendez-Montealvo MG, Ottenhof MA, Farhat IA, Bello-Pérez LA. Determination of the molecular and structural charactersitics of okenia, mango, and banana starches. Journal of Agricultural and Food Chemistry. 2005;**53**:495-501

[50] Lindeboom N, Chang PR, Tyler RT. Analytical, biochemical, physicochemical aspects of starch granule size, with emphasis on small granule starches: A review. Starch/Stärke. 2004;**56**(3-4):89-99

[51] Wanikar R, Upadhyay A, Kotwal S. Effect of processing on granular and thermal properties of starch and resistant starch from kodo and kutki. International Journal of Food Sciences and Nutrition. 2018;**7**:83-90

[52] Gidley MJ, Bociek SM. Molecular organization in starches: a carbon 13 CP/ MASNMR study. Journal of the American Chemical Society. 1985;**107**(24): 7040-7044

## Starch Biodegradable Films Produced by Electrospraying

*Verónica Cuellar Sánchez, Marcela González Vázquez, Alitzel B. García-Hernández, Fátima S. Serrano-Villa, Ma. de la Paz Salgado Cruz, Arturo García Bórquez, Eduardo Morales-Sánchez, Reynold R. Farrera-Rebollo and Georgina Calderón-Domínguez*

#### **Abstract**

The use of particles obtained from biopolymers is of interest in fields such as bioengineering and nanotechnology, with applications in drug encapsulation, tissue engineering, and edible biofilms. A method used to obtain these particles is electrohydrodynamic atomization (EHDA), which can generate different structures depending on the process conditions and raw materials used, opening a wide range of research in the biopolymers field, where starch is considered an excellent material to produce edible and biodegradable films. This chapter is a compilation and analysis of the newest studies of this technique, using starch with or without modifications to prepare films or membranes and their potential applications. A systematic literature review, focused on starch, and EHDA was carried out, finding 158 articles that match these criteria. From these results, a search inside them, using the words edible and biodegradable was conducted, showing 93 articles with these key words. The information was analyzed observing the preference to use corn, potato, rice, and cassava starches, obtaining mainly scaffolds and fibers and, in much less proportion, films or capsules. This review shows a window of opportunity for the study of starchy materials by EHDA to produce films, coatings, and capsules at micro or nano levels.

**Keywords:** starch, electrospraying, electrospinning, edible films, biodegradable films

#### **1. Introduction**

Over the last decade, due to its multidisciplinary nature, the field of nanotechnology has seen a sharp increase in its applications in several areas, mainly on the "bottom-up" and "top-down" approaches. These terms refer to the synthesis processes used to produce new or modified materials, scaling up atom by atom to form a larger product structure or breaking apart larger particles into micro/nanomaterials, respectively [1]. One of the most reported of these methods, used in the food industry, tissue, and environmental engineering, is the electrohydrodynamic atomization technique (EHDA) [2–4], a

"bottom-up" nanotechnology approach, which has been employed for the production of membranes, particles, encapsulation, and edible or biodegradable films.

When EHDA began to be used for the design of micro fibers, nano fibers, and membranes, many of the products were developed with synthetic polymers, which continue giving very good results to this day. However, as the need for greener technologies and more ecofriendly products increased, the use of biopolymers also rose. Thus, carbohydrates such as cellulose, pectin, chitosan, alginate, and starch, single or blended with other bio or synthetic polymers, have increasingly been proposed for the production of films, membranes, fibers, and encapsulates. Among these carbohydrates, starch represents a very good option, as it can be found in large quantities in nature, besides being an inexpensive biopolymer, normally found in leaves, stems, seeds, roots, and tubers or other sources such as algae and bacteria.

In this chapter, we present the basis of EHDA technology and summarize some of the data reported in the most recent studies for the production of fibers, films, and membranes using starch as raw material and analyzing the modifications required to be able to generate these starchy products.

#### **2. Electrohydrodynamic atomization (EHDA)**

EHD procesess encompasses two methods called electrohydrodynamic spinning and electrohydrodynamic atomization, better known as electrospinning and electrospraying, respectively [5]. Electrospinning allows for the production of membranes from electrospun fibers, and electrospraying allows for the synthesis of materials such as core/shell, micro/nanoparticles, encapsulates, and films from fine droplets.

A typical EHDA device (**Figure 1**) consists of four parts: (1) a high-voltage power supply (typically ranging from 1 to 30 kV), (2) a syringe pump, (3) a capillary containing the conductive polymer solution (commonly a syringe with a stainless-steel

#### *Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

needle), and (4) a collector (stainless-steel rotatory drum or static conductive plate) [2]. These components are present regardless of the method. Moreover, depending on the material to be synthesized, the equipment can be set in two standard configurations (**Figure 2**): horizontal (**Figure 2a**) or vertical (**Figure 2b**) [6], which have been used in the production of films formed by micro/nanoparticles [7] and encapsulates [8] in dry (**Figure 2c**) or wet (**Figure 2d**) configurations.

On the other hand, and in addition to the two standard configurations mentioned above, several modifications have been studied. These modifications have been done according to specific needs; for example, horizontal dry electrospinning (**Figure 2b**) is used to obtain membranes based on hydrolyzed collagen and polyvinyl alcohol with potential use for wound protection [9], and vertical wet spinning (**Figure 2c**) is used to synthesize membranes from polyvinyl alcohol and poly(ethyleneimine), to remove heavy metals from wastewater [10]. In these examples, the collector can be either immersed in a liquid, or dry, (**Figure 2d**).

Characteristics such as product morphology and size are affected by the properties of the solution (viscosity, polymer concentration, molecular weight of polymer, surface tension, conductivity), process variables (applied voltage, working-distance from needle to collector, flow rate), and environmental parameters (temperature, humidity, airflow) [11], resulting in products with different properties and intended uses.

**Figure 2.**

*Electrohydrodynamic configurations: (I) horizontal, (II) vertical. Electrohydrodynamic types: (a) horizontal dry electrospraying, (b) horizontal dry electrospinning, (c) vertical wet electrospinning, (d) vertical dry/wet electrospraying.*

But, how are fibers or particles formed? In the case of fibers, when the electrical voltage is applied to the conductive polymer solution in the syringe, electrical charges accumulate on the surface of the liquid and, depending on the surface tension, the polymer solution remains within the capillary, not flowing. As the mutual repulsion of charges produces a force directly opposite to the surface tension and the intensity of the electric field increases, the solution reaches the end of the capillary, acquiring a conical shape, called a "Taylor cone." Consequently, when the electric field reaches a critical value, that is, when the repulsive electrical force exceeds the surface tension force, a jet of the polymer solution is produced at the tip of the cone. As the jet spreads through the air, the solvent in the solution evaporates, forming a polymeric micro or nanofiber. Finally, the fibers are deposited in the collector in the form of a nonwoven micro/nanofiber membrane [6–11].

Regarding the synthesis of films, micro/nanoparticles, and encapsulates, unlike membranes, these materials are formed from solutions of low polymer concentration, which allows the jet's destabilization and the formation of highly identically charged fine droplets that do not agglomerate. In other words, a polymeric solution in the capillary is sprayed from the nozzle into the collector under a high-voltage application due to electrostatic forces. Here, on the flight in time to the collector, the solvent evaporates and particles are produced [11, 12].

The fibers and the particles produced by these methodologies show a high surface area to volume ratio, good mechanical, electrical, and thermal properties, and smooth, homogenous, and variable morphologies, mainly as a result of the process parameters' manipulation, which in turn derives in the shape that the jet takes during the ejection process [13].

As mentioned earlier, the parameters that govern the EHDA process are properties of the solution, process conditions, and environmental parameters, all of which determine the morphology and diameter of the fibers or particles [11, 14].

EHDA products can be synthesized using a wide range of materials, including biopolymers from animals, plants, and algae, such as collagen, chitosan, gelatin, pectin, zein, cellulose, alginate, starch, and others, and synthetic polymers, such as polyethene oxide, polyvinyl alcohol, and polycaprolactone, among others [5, 6, 13]. However, due to their low molecular weight and mechanical properties, natural and synthetic polymers are commonly used in tandem. Furthermore, materials such as carbon-based nanomaterials, ceramics, and metallic nanoparticles have also been applied in combination with chitosan or casein nanofibers, to name a few [15, 16]. In general, since its invention, the application of the EHDA technique increased considerably, due to it being straightforward, inexpensive (low solution consumption), controllable, and reproducible [17], with starch being considered a potential raw material to be used in this technique.

#### **3. Starch**

Starch is found in all plants as a product of photosynthesis and is the main storage reserve carbohydrate of plants and the primary source of calories in the human diet. It is also a very important renewable and biodegradable raw material for the industry [18]. The main sources of starch are cereals (corn, wheat, rice, barley) and tubers or roots (potatoes, tapioca, cassava) [19], corn being the most important, followed by potato and cassava.

Starch is a polysaccharide composed of α-glucose polymer molecules: a linear one called amylose and a branched one known as amylopectin. The proportion of these

*Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

molecules varies depending on the source, with the most common being an amylose content of 13–30%. However, it is possible to find amylopectin-only materials [20, 21], mainly cereals, referred to as waxy cereal varieties (corn, sorghum, rice). These differences in starch composition result in diverse physicochemical properties, affecting properties such as gelatinization temperature, solubility, and final viscosity of starch slurries.

Starch can be extracted by different methods, most of them being classified as dry or wet, and in both cases looking to maintain its functional properties at the highest possible yields and purity [22] and without damaging the crystalline phase or promoting depolymerization [23] of the materials. One of these methods is dry milling, which consists of the grinding of the samples and an air classification [24]. This method simplifies the handling of large amounts of liquid in comparison to wet milling [22] but increases the proportion of damaged starch [25], resulting in a lower quality product [26].

Conversely, wet milling is used to extract starch from flour by producing an aqueous slurry, which is filtrated and washed at least two times [27]; the starch obtained in this process has a higher purity than dry milling [28]. In most wet extraction processes, a reactant, such as sodium bisulfite [29], metabisulfite [30], sodium hydroxide [31], oxalic acid/ammonium oxalate [32], or low concentrations of citric acid [33], is added, mainly to facilitate protein separation. Other techniques, such as sonication [34] or freezing, to assist the extraction process to increase the starch yields have been reported as well.

#### **3.1 Starch sources**

Starch is organized into tiny particles called grains or starch granules, and their size and shape are characteristic of each botanical species (**Table 1**). It is known that the granule size is decisive in its processability, which affects the solubility (in a plasticizer medium) and the swelling power, facilitating the release of soluble polymer chains for the formation of a single coherent amorphous phase [47–49].

The size of the starch granule varies from a very small size (4 μm or less), such as that found in amaranth, jicama, or rice, up to 100 μm from potato granules [21]. Most of the materials do not present a unique size and, in some cases, have very different shapes. As an example, in barley starch, there are two populations of granules: small


#### **Table 1.**

*Some starch characteristics.*

2–5 micron-long spheres and large 15–25 micron-long lenticular granules [49]. In the case of rice, corn, and waxy corn starches, they have a polyhedral shape, while the granules of potato starch are ovoid. Cassava follows a similar behavior; starch granules are not uniform, are round with truncated terminals, have a well-defined nucleus, and their size varies between 4 and 35 μm with an average of 20 μm [50, 51]. These differences in size, as well as in amylose and amylopectin content, promote the various functional properties of the starch, such as gelatinization temperatures and thus lead to different industrial applications.

#### **3.2 Modified starches**

Starch has many applications in food and nonfood industries based on its physicochemical and functional properties; for example, it is used in the pharmaceutical industry as a raw material for the production of dextrose and serum, as an excipient in the manufacture of tablets and pills, and as capsules [52]. It has been also used as an adhesive, binder, thickener, and co-builder; in gelling, complexing, and flocculating agents; and in the paper and corrugating industry. Another application is in the preparation of edible and biodegradable films, due to barrier characteristics (O2 and CO2). However, most of these applications are carried out employing modified starches [21, 52–54].

Starches have functional properties that can be related to their final use and vary depending on the granule secondary and tertiary structures and if the starch has been modified or remains native. These differences influence the gelatinization temperature, type of diffraction patterns, crystallinity degree, solubility, clarity, viscosity, water-retention capacity, and swelling capacity, which help to explain the stability of the biopolymer, and therefore suggest its proper application [55, 56].

Starch can be modified by different procedures, either physical or chemical, reaching different final properties and characteristics. The most common physical modifications include heating starch slurries in boiling water or autoclaving at 121°C, thus promoting gelatinization (low and high temperatures) and as a consequence an increase in its solubilization capacity [56]. Other common physical procedures include ultrasonication [57] and ball milling [58]. Regarding chemical modifications, these procedures change the starch structure, by excising the molecule during a hydrolysis process or by introducing new components as a result of oxidation, esterification, or etherification [53], increasing in most of the cases its solubility and a loss of crystallinity [51, 54].

#### **4. EHDA starch films**

Many studies have been carried out regarding electrohydrodynamic atomization, with the first publications about this technique using biopolymers, and specifically starch, coming out in 2003. Many of these documents report on fibers and capsules of different sizes (micro or nano). These were studied alone or as part of scaffolds, membranes, or films—with one or more layers—and built from different polymeric materials besides starch, either of biological or of chemical origin.

Starch is a common material widely distributed in nature, with EHDA products being mainly built from commercial sources, such as corn and maize starch are the ones that have different amylose/amylopectin content [59–67], or others such as potato [66, 68–73], rice [74], and cassava or tapioca starches [75–79].

The use of chemically modified starches, such as cationic starch prepared from hydroxyethylated starch [80], hydroxypropyl starch [81], or octenylsuccinylated

#### *Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

starch [82], is also a common practice, while the study of noncommercial biopolymers sources is less frequent [66, 74, 83].

Another normal practice observed for the elaboration of EHDA starch products is combining starch with other polymers, being PVA (polyvinyl alcohol), PCL (polycaprolactone), and PLA (polylactic acid) widely employed [61, 68, 76, 78, 80, 84, 85]. The use of PEO (polyethylene oxide), PMMA (polymethyl methacrylate), and TPU (thermoplastic polyurethane) has also been reported, although in fewer amounts [81, 86].

Starch in its native form is seldom used for the elaboration of EHDA starch products due to its poor solubility and hydrophobicity. This is the reason why it is used in combination with other polymers or modified by physical or chemical procedures.

In this regard, heating by conventional techniques, which render gelatinized starch, is one of the most common procedures. More recently, microwave heating has been reported [74], with both methods increasing the solubility of this polysaccharide. The temperatures reported in these studies use to promote the starch solubilization varied from 70°C up to 140°C, and the heating duration from 10 min to 720 min, with differences seeming to be mostly related to the temperatures used [59–61, 67, 73, 74, 77, 81, 83, 87, 88]. Ultrasonic starch disruption has also been cited [59, 70], along with aqueous DMSO solution to improve starch dissolution [62, 63, 66, 67, 75, 76, 83, 84, 86].

When preparing polysaccharide solutions for electrospinning, the [63] concentrations of native starch [63] are low, ranging from 0.5% [74] to 15%. Higher concentrations of these materials have been reported for commercial soluble (50%) and cassava (66%) starches [71, 87]. In most cases, the solvents added correspond to water [59, 62, 68, 78, 80, 88] or DMSO solutions [63, 70, 75, 76, 83, 87] and in lower amounts to acetic acid, formic acid, ethanol, chloroform, DCM and DMF solutions [71, 79, 84, 85, 89]. **Figure 3** summarized the main steps to prepare starch solutions for electrospraying.

Once the starch solution is obtained, it is fed to the EHDA equipment, and the flow rate, voltage, and distance to collector are set. Most authors reported using

#### **Figure 3.**

*General method to prepare starch solutions for electrospraying. Dotted lines indicate alternative methodologies.*


*\*Outer diameter.*

*DC: distance to collector; V: voltage; FT: flow rate; SND: syringe needle inner diameter. NR: no reported. PVA: polyvinyl alcohol; PCL: polycaprolactone; PET; polyethylene terephthalate; PLA: polylactic acid; PEO: polyethylene oxide; TPU: thermoplastic polyurethane.*

#### **Table 2.**

*Process conditions employed to develop EHDA starch products. Some examples.*

voltages between 0 and 20 kV (66%), flow rates smaller than or equal to 1.0 mL/h (81%), and highly variable distances to collector (5–30 cm); in most of these cases, micro and nanofibers or mats were developed, with the exception of two works reporting capsules [86, 87] and two reporting films [59, 67]. However, in some cases, more than one method to prepare mats or films is used, combining, for example, both electrospraying and casting or others [85]. **Table 2** shows some examples of specific process conditions used to obtain the different EHDA starch products.

#### **5. Conclusions**

It is of notice that even though starch electrospraying has been studied for many years, most of this research has been focused exclusively into an electrospinning field, with very few works having been published related to the production of edible or biodegradable films, coatings, or microcapsules.

This observation shows a window of opportunity, for the study of new starchy materials and to better understand this technique and its intricacies. Some examples include the

effects of different assay parameters, such as syringe inner diameter or the size of starch granules and their relationship to film properties, factors that have not been reported yet. Several studies with other biopolymers [88, 90–92], as well as starch, can serve as a basis for the development of new and improved ecological coating materials.

### **Acknowledgements**

Verónica Cuellar Sánchez, Marcela González Vázquez and Alitzel B. García-Hernández would like to thank CONACyT and BEIFI-IPN for the scholarships provided and the financial support for this work. This research was funded through the projects: 20195500, 20201679, 20201695, 20210624, and 20211381 from the Instituto Politécnico Nacional (IPN, Mexico) and 1668 from CONACyT.

#### **Conflict of interest**

The authors declare no conflict of interest.

### **Author details**

Verónica Cuellar Sánchez1 , Marcela González Vázquez1 , Alitzel B. García-Hernández1 , Fátima S. Serrano-Villa1 , Ma. de la Paz Salgado Cruz1,2, Arturo García Bórquez3 , Eduardo Morales-Sánchez4 , Reynold R. Farrera-Rebollo1 and Georgina Calderón-Domínguez1 \*

1 Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Gustavo A. Madero, México

2 Consejo Nacional de Ciencia y Tecnología (CONACyT), Ciudad de México, México

3 Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Gustavo A. Madero, México

4 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Querétaro, Instituto Politécnico Nacional, México

\*Address all correspondence to: gcalderon@ipn.mx

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Nanotechnology. 2021. Encyclopedia Britannica [Internet]. Available from: https://www.britannica.com/technology/ nanotechnology [Accessed: 8-08-2021]

[2] Anu-Bhushani J, Anandharamakrishnan C. Electrospinning and electrospraying techniques: Potential food based applications. Trends in Food Science and Technology. 2014;**38**:21-33. DOI: 10.1016/j.tifs.2014.03.004

[3] Eltom A, Zhong G, Muhammad A. Scaffold techniques and designs in tissue engineering functions and purposes: A review. Hindawi Advances in Materials Science and Engineering. 2019;**3429527**: 1-13. DOI: 10.1155/2019/3429527

[4] Wang X, Min M, Liu Z, Yang Y, Zhou Z, Zhu M, et al. Poly (ethyleneimine) nanofibrous affinity membrane fabricated via one step wetelectrospinning from poly (vinyl alcohol) doped poly(ethyleneimine) solution system and its application. Journal of Membrane Science. 2011;**379**:191-199. DOI: 10.1016/j.memsci.2011.05.065

[5] Soares RMD, Siqueira NM, Prabhakaram MP, Ramakrishna S. Electrospinning and electrospray of bio-based and natural polymers for biomaterials development. Materials Science and Engineering: C. 2018;**92**:969- 982. DOI: 10.1016/j.msec.2018.08.004

[6] Thenmozhi S, Dharmaraj N, Kadirvelu K, Kim HY. Electrospun nanofibers: New generation materials for advanced applications. Materials Science and Engineering: B. 2017;**217**:36-48. DOI: 10.1016/j.mseb.2017.01.001

[7] Valdespino-León M, Calderón-Domínguez G, Salgado-Cruz MDLP, Rentería-Ortega M, Farrera-Rebollo RR, Morales-Sánchez E, et al. Biodegradable electrosprayed pectin films: An alternative to valorize coffee mucilage. Waste and Biomass Valorization. 2020;**12**:2477-2494. DOI: 10.1007/s12649-020-01194-z

[8] Rentería-Ortega M,

Salgado-Cruz MDLP, Morales-Sánchez E, Alamilla-Beltrán L, Farrera-Rebollo RR, Valdespino-León M, et al. Effect of electrohydrodynamic atomization conditions on morphometric characteristics and mechanical resistance of chia mucilage-alginate particles. CyTA - Journal of Food. 2020;**18**:461-471. DOI: 10.1080/19476337.2020.1775706

[9] García-Hernández AB, Morales-Sánchez E, Calderón-Domínguez G, Salgado-Cruz MDLP, Farrera-Rebollo RR, Vega-Cuellar MA, et al. Journal of Applied Polymer Science. 2021:e51197. DOI: 10.1002/app.51197

[10] Sonseca A, Sahay R, Stepien K, Bukala J, Wcislek A, McClain A, et al. Architectured Helically Coiled Scaffolds from Elastomeric Poly(butylene succinate) (PBS) Copolyester via Wet Electrospinning. Materials Science and Engineering: C. 2020;**108**(110505). DOI: 10.1016/j.msec.2019.110505.

#### [11] Castro-Coelho S,

Nogueiro-Estevinho B, Rocha F. Encapsulation in food industry with emerging electrohydrodynamic techniques: Electrospinning and electrospraying - A review. Food Chemistry. 2021;**339**:127850. DOI: 10.1016/j.foodchem.2020.12785

[12] Boda SK, Li X, Xie J. Electrospraying an enabling technology for pharmaceutical and biomedical applications: A review. Journal of

*Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

Aerosol Science. 2018;**125**:164-181. DOI: 10.1016/j.jaerosci.2018.04.00

[13] Lim LT, Mendes AC, Chronakis IS. Electrospinning and electrospraying technologies for food applications. In: Advances in Food and Nutrition Research. In: Food Applications of Nanotechnology; 2019. pp. 167-234. DOI: 10.1016/bs.afnr.2019.02.005

[14] Calderón-Arenas JM, Martínez-Rincón HA. Obtención de fibras poliméricas a partir de la técnica de electrospinning para aplicaciones biomédicas [thesis]. Santiago de Cali: Universidad Autónoma de Occidente; 2012. Colombia

[15] Selvaraj S, Thangam R, Fathima NN. Electrospinning of casein nanofibers with silver nanoparticles for potential biomedical applications. International Journal of Biological Macromolecules. 2018;**120**:1674-1681. DOI: 10.1016/j. ijbiomac.2018.09.177

[16] Yan E, Fan S, Li X, Wang C, Sun Z, Ni L, et al. Electrospun polyvinyl alcohol/chitosan composite nanofibers involving Au nanoparticles and their in vitro release properties. Materials Science and Engineering: C. 2013;**33**:461-465. DOI: 10.1016/j.msec.2012.09.014

[17] Jaworek A, Sobczyk AT. Electrospraying route to nanotechnology: An overview. Journal of Electrostatics. 2008;**66**:197-219. DOI: 10.1016/j. elstat.2007.10.001

[18] INECOL. 2021. ¿Qué es el almidón? [Internet]. Available from: https://www. inecol.mx/inecol/index.php/es/ct-menuitem-25/ct-menu-item-27/ 17-ciencia-hoy/1376-que-es-el-almidon [Accessed: 2021-08-08]

[19] French D. Physical and chemical structure of starch and glycogen. In:

Carbohydrates and Their Roles. 1st ed. Westport, Conn: AVI Publishing; 1969

[20] Astiasarán I, Martinez JA. Alimentos: composición y propiedades. Segunda edición. Madrid, Spain: McGraw-Hill Interamericana; 2000. p. 364

[21] Badui DS. Química de los Alimentos. Cuarta edición. Pearson: Addison Wesley; 2006. p. 736

[22] Lee HC, Htoon AK, Paterson JL. Alkaline extraction of starch from Australian lentil cultivars Matilda and Digger optimized for starch yield and starch and protein quality. Food Chemistry. 2007;**102**:551-559. DOI: 10.1016/j.foodchem.2006. 03.042

[23] Han X, Hamaker BR. Partial leaching of granule-associated proteins from rice starch during alkaline extraction and subsequent gelatinization. Starch/Stärke. 2002;**54**:454-460. DOI: 10.1002/ 1521-379X (200210)54:10<454: AID-STAR454>3.0.CO;2-M

[24] Tian S, Kyle WSA, Small DM. Pilot scale isolation of proteins from fields peas (Pisum sativem L.) for use as food ingredients. International Journal of Food Science and Technology. 1999;**34**(33-39). DOI: 10.1046/ j.1365-2621.1999.00236.x

[25] Kringel DH, Mello SL, Da Rosa E, Guerra AR. Methods for the extraction of roots, pulses, pseudocereals, and other unconventional starch source: A review. Starch/Stärker. 2020;**72**:11-12. DOI: 10.1002/star.201900234

[26] Steeneken PA, Helmens HJ. Laboratory-scale Dry/wet-milling process for the extraction of starch and gluten from wheat. Starch/Stärker. 2009;**61**:389-397. DOI: 10.1002/ star.200800065

[27] Zheng GH, Sosulski FW, Tyler RT. Wet-milling, composition and functional properties of starch and protein isolated from buckwheat groats. Food Research International. 1999;**30**:493-502. DOI: 10.1016/S0963-9969(98)00021-0

[28] Kringel DH, Mello SL, Da Rosa E, Guerra AR. Methods for the extraction of roots, pulses, pseudocereals, and other unconventional starch source: A review. Starch/Stärker. 2020;**72**:11-12. DOI: 10.1002/star.201900234

[29] Lim ST, Lee JH, Shin DH, Lim HS. Comparison of protein extraction solutions for rice starch isolation and effects of residual protein content on starch pasting properties. Starch/Stärker. 1999;**51**:120-125. DOI: 10.1002/ (SICI)1521-379X(199904)51:4<120: AID-STAR120>3.0.CO;2-A

[30] Ji Y, Seetharaman K, White PJ. Optimizing a small-scale corn-starch extraction method for use in the laboratory. Cereal Chemistry. 2004;**81**:55-58. DOI: 10.1094/ CCHEM.2004.81.1.55

[31] Matsunaga N, Takahashi S, Kainuma K. Rice starch isolation from newly developed rice cultivars by the improved alkali method. Journal of Applied Glycoscience. 2003;**50**:913. DOI: 10.5458/jag.50.9

[32] Daiuto E, Cereba M, Sarmento S, Vilpoux O. Effects of extraction methods on yam (Dioscorea alata) starch characteristics. Starch/Stärker. 2005;**57**:153-160. DOI: 10.1002/ star.200400324

[33] Pascoal AM, Di-Medeiros CB, Batista KA, Gonçalves MI, Moraes L, Ferandes KF. Extraction and chemical characterization of starch. Carbohydrate Polymers. 2013;**98**:1304-1310. DOI: 10.1016/j.carbpol.2013.08.009

[34] González LB, Calderón G, Salgado MP, Díaz M, Ramírez M, Chanona JJ, et al. Ultrasound-assisted extraction of starch from frozen jicama (P. erosus) roots: Effect on yield, structural characteristics and thermal properties. CyTA Journal of Food. 2018;**16**:1738-1746. DOI: 10.1080/19476337.2018.1462852

[35] Wang B, Dong Y, Fang Y, Gao W, Kang X, Liu P, et al. Effects of different moisture contents on the structure and properties of corn starch during extrusion. Food Chemistry. 2021;**368**:130804. DOI: 10.1016/j. foodchem.2021.130804

[36] Lutfi Z, Kalim Q, Shahid A, Nawab A. Water chestnut, rice, corn starches and sodium alginate. A comparative study on the physicochemical, thermal and morphological characteristics of starches after dry heating. International Journal of Biological Macromolecules. 2021;**184**:476-482. DOI: 10.1016/j. ijbiomac.2021.06.128

[37] Sun Y, Wang M, Ma S, Wang H. Physicochemical characterization of rice, potato, and pea starches, each with different crystalline pattern, when incorporated with Konjac glucomannan. Food Hydrocolloids. 2020;**101**:105499.7. DOI: 10.1016/j.foodhyd.2019.105499

[38] Datta D, Halder G. Effect of media on degradability, physico-mechanical and optical properties of synthesized polyolefinic and PLA film in comparison with casted potato/corn starch biofilm. Process Safety and Environmental Protection. 2019;**124**:39-62. DOI: 10.1016/j.psep.2019.02.002

[39] Lewandowicz G, Soral-Śmietana M. Starch modification by iterated syneresis. Carbohydrate Polymers. 2004;**56**:403- 413. DOI: 10.1016/j.carbpol.2004.03.013

*Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

[40] Hsieh CF, Liu W, Whaley JK, Shi YC. Structure, properties, and potential applications of waxy tapioca starches–A review. Trends in Food Science and Technology. 2019;**83**:225-234. DOI: 10.1016/j.tifs.2018.11.022

[41] Cai L, Shi YC. Structure and digestibility of crystalline short-chain amylose from debranched waxy wheat, waxy maize, and waxy potato starches. Carbohydrate Polymers. 2010;**79**:1117- 1123. DOI: 10.1016/j.carbpol.2009. 10.057

[42] Elhassan MS, Emmambux MN, Hays DB, Peterson GC, Taylor JR. Novel biofortified sorghum lines with combined waxy (high amylopectin) starch and high protein digestibility traits: Effects on endosperm and flour properties. Journal of Cereal Science. 2015;**65**:132-139. DOI: 10.1016/j.jcs.2015.06.017

[43] Ali TM, Hasnain A. Morphological, physicochemical, and pasting properties of modified white sorghum (Sorghum bicolor) starch. International Journal of Food Properties. 2014;**17**:523-535. DOI: 10.1080/10942912.2012.654558

[44] Yuryev VP, Krivandin AV, Kiseleva VI, Wasserman LA, Genkina NK, Fornal B, et al. Structural parameters of amylopectin clusters and semi-crystalline growth rings in wheat starches with different amylose content. Carbohydrate Research. 2004;**339**: 2683-2691. DOI: 10.1016/j.carres.2004. 09.005

[45] Ramírez-Miranda M, Ribotta PD, Silva-González AZZ, Salgado-Cruz MDLP, Andraca-Adame JA, Chanona-Pérez JJ, et al. Morphometric and crystallinity changes on jicama starch (Pachyrizus erosus) during gelatinization and their relation with in vitro glycemic index. Starch – Stärke. 2017;**69**:1600281. DOI: 10.1002/star.201600281

[46] Salas C, Medina JA. Caracterización morfológica del gránulo de almidón nativo: Apariencia, forma, tamaño y su distribución. Revista de ingeniería. 2008;**27**:56-62. DOI: 10.16924/ revinge.27.6

[47] Jeroen JG, v S and Vliegenthart FGJ. Crystallinity in starch plastics: consequences for material properties. Trends in Biotechnology. 1997;**15**:208-213. DOI: 10.1016/S0167-7799(97)01021-4

[48] Kaur L, Singh N, Singh SN. Some properties of potatoes and their starches II. Morphological, thermal and rheological properties of starches. Food Chemistry. 2002;**79**:183-192. DOI: 10.1016/S0308-8146(02)00130-9

[49] Singh N, Singh J, Kaur L, Singh SN, Singh GB. Morphological, termal and rheologycal properties of starches from different botanical sources. Food Chemistry. 2003;**81**:219-231. DOI: 10.1016/S0308-8146(02)00416-8

[50] Sánchez T, Aristizábal J. Guía técnica para producción y análisis de almidón de yuca. FAO [Internet]2007. p. 129 Available from: http://www.fao.org/3/ a1028s/a1028s.pdf. [Accessed: 2021-08-08]

[51] Valdés SE. Hidratos de carbono. En: Badui D. Salvador Química de los Alimentos. Cuarta edición. Pearson: Addison Wesley; 2006. p 29-107.

[52] Röper H. Renewable raw materials in Europe — Industrial utilisation of starch and sugar [1]. Starch-Stärke. 2002;**54**:89- 99. DOI: 10.1002/1521- 379X(200204)54:3/4<89: AID-STAR89>3.0.CO;2-I

[53] Lee FA. Basic of Food Chemistry. 2nd ed. INC. Westport, Conn: The AVI publishing Company; 1983. p. 546. DOI: 10.1007/978-94-011-7376-6

[54] Hoover R. The Impact of heatmoisture treatment on molecular structures and properties of starches isolated from different botanical sources. Critical Reviews in Food Science and Nutrition. 2010;**50**:835-847. DOI: 10.1080/10408390903001735

[55] Mukerjea R, Slocum G, Robyt JF. Determination of the maximum water solubility of eight native starches and the solubility of their acidic-methanol and -ethanol modified analogues. Carbohydrate Research. 2007;**342**:103- 110. DOI: 10.1016/j.carres.2006.10.022

[56] Fernando S, Paranavithana T, Dissanayaka U, Premarathna W, Atambawa A, de Silva N, et al. Effect of starch particle size reduction on the performance of sized warp yarns. Moratuwa Engineering Research Conference (MERCon). 2015:60-63. DOI: 10.1109/mercon.2015.7112321

[57] Dai L, Li C, Zhang J, Cheng F. Preparation and characterization of starch nanocrystals combining ball milling with acid hydrolysis. Carbohydrate Polymers. 2018;**180**:122- 127. DOI: 10.1016/j.carbpol.2017.10.015

[58] Pareta R, Edirisinghe M. A novel method for the preparation of starch films and coatings. Carbohydrate Polymers. 2006;**63**:425-431. DOI: 10.1016/j.carbpol.2005.09.018

[59] Espíndola-González A, Martínez-Hernández AL, Fernández-Escobar F, Castaño VM, Brostow W, Datashvili T, et al. Natural-synthetic hybrid polymers developed via electrospinning: The effect of PET in chitosan/starch system. International Journal of Molecular Sciences. 2011;**12**:1908-1920. DOI: 10.3390/ijms12031908

[60] Wang H, Wang W, Jiang S, Jiang S, Zhai L, Qin. Poly (vinyl alcohol)/

oxidized starch fibres via electrospinning technique: Fabrication and characterization. Iranian Polymer Journal. 2011;**20**:551-558

[61] Kong L, Ziegler GR. Quantitative relationship between electrospinning parameters and starch fiber diameter. Carbohydrate Polymers. 2013;**92**: 1416-1422. DOI: 10.1016/j.carbpol.2012. 09.026

[62] Kong L, Ziegler GR. Formation of starch-guest inclusion complexes in electrospun starch fibers. Food Hydrocolloids. 2014;**38**:211-219. DOI: 10.1016/j.foodhyd.2013.12.018

[63] Ledezma-Oblea JG, Morales-Sánchez E, Gaytán-Martínez M, Figueroa-Cárdenas JD, Gaona-Sánchez VA. Corn starch nanofilaments obtained by electrospinning. [Nanofilamentos de almidón de maíz obtenidos por electrospinning] Revista Mexicana De Ingeniera Química. 2015;**14**:497-502

[64] Fabra MJ, López-Rubio A, Sentandreu E, Lagaron JM. Development of multilayer corn starch-based food packaging structures containing β-carotene by means of the electrohydrodynamic processing. Starch/ Staerke. 2016;**68**(7-8):603-610. DOI: 10.1002/star.201500154

[65] Hemamalini T, Giri Dev VR. Comprehensive review on electrospinning of starch polymer for biomedical applications. International Journal of Biological Macromolecules. 2018;**106**:712-718. DOI: 10.1016/j. ijbiomac.2017.08.079

[66] Cai J, Zhang D, Zhou R, Zhu R, Fei P, Zhu Z-Z, et al. Hydrophobic interface starch nanofibrous film for food packaging: From bioinspired design to self-cleaning action. Journal of

*Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

Agricultural and Food Chemistry. 2021;**69**(17):5067-5075. DOI: 10.1021/acs. jafc.1c00230

[67] Šukyte J, Adomavičiute E, Milašius R. Investigation of the possibility of forming nanofibres with potato starch. Fibres and Textiles in Eastern Europe. 2010;**82**(5):24-27

[68] López-Córdoba A, Estevez-Areco S, Goyanes S. Potato starch-based biocomposites with enhanced thermal, mechanical and barrier properties comprising water-resistant electrospun poly (vinyl alcohol) fibers and yerba mate extract. Carbohydrate Polymers. 2019;**215**:377-387. DOI: 10.1016/j. carbpol.2019.03.105

[69] Mistry P, Chhabra R, Muke S, Sathaye S, Jain R, Dandekar P. Fabrication and characterization of starch-TPU based nanofibers for wound healing applications. Materials Science and Engineering: C. 2020;**119**:111316. DOI: 10.1016/j.msec.2020.111316

[70] Fonseca LM, Radünz M, dos Santos Hackbart HC, da Silva FT, Camargo TM, Bruni GP, et al. Electrospun potato starch nanofibers for thyme essential oil encapsulation: Antioxidant activity and thermal resistance. Journal of the Science of Food and Agriculture. 2020; **100**(11):4263-4271. DOI: 10.1002/ jsfa.10468

[71] Rodríguez-Sánchez IJ, Vergara-Villa NF, Clavijo-Grimaldo D, Fuenmayor CA, Zuluaga-Domínguez CM. Ultrathin single and multiple layer electrospun fibrous membranes of polycaprolactone and polysaccharides. Journal of Bioactive and Compatible Polymers. 2020;**35**(4-5): 351-362. DOI: 10.1177/0883911520944422

[72] Alinaqi Z, Khezri A, Rezaeinia H. Sustained release modeling of clove

essential oil from the structure of starch-based bio-nanocomposite film reinforced by electrosprayed zein nanoparticles. International Journal of Biological Macromolecules. 2021;**173**:193- 202. DOI: 10.1016/j.ijbiomac.2021.01.118

[73] Uygun E, Yildiz E, Sumnu G, Sahin S. Microwave pretreatment for the improvement of physicochemical properties of carob flour and rice starch– based electrospun nanofilms. Food and Bioprocess Technology. 2020;**13**:838-850. DOI: 10.1007/s11947-020-02440-x

#### [74] Sunthornvarabhas J,

Chatakanonda P, Piyachomkwan K, Sriroth K. Electrospun polylactic acid and cassava starch fiber by conjugated solvent technique. Materials Letters. 2011;**65**(6):985-987. DOI: 10.1016/j. matlet.2010.12.038

[75] Sunthornvarabhas J, Chatakanonda P, Piyachomkwan K, Chase GG, Kim H-J, Sriroth K. Physical structure behavior to wettability of electrospun poly (lactic acid)/polysaccharide composite nanofibers. Advanced Composite Materials. 2013;**22**(6):401-409. DOI: 10.1080/ 09243046.2013.843815

[76] Sutjarittangtham K, Jaiturong P, Intatha U, Pengpat K, Eitssayeam S, Sirithunyalug J. Fabrication of natural tapioca starch fibers by a modified electrospinning technique. Chiang Mai Journal of Science. 2014;**41**(1):213-223

[77] Sutjarittangtham K, Tragoolpua Y, Tunkasiri T, Chantawannakul P, Intatha U, Eitssayeam S. The Preparation of Electrospun Fiber Mats Containing Propolis Extract/CL-CMS for Wound Dressing and Cytotoxicity, Antimicrobial, Anti-Herpes Simplex Virus. Journal of Computational and Theoretical Nanoscience. 2015;**12**(5):804-808. DOI: 10.1166/jctn.2015.3807

[78] Pacheco da CE, Martins FL, Radünz M, Silva da FT, Avila EG, Gandra, da Rosa EZ, Dellinghausen BC. Pinhão coat extract encapsulated in starch ultrafine fibers: Thermal, antioxidant and antimicrobial properties and in vitro biological digestion. Journal of Food Science. 2021;**86**:2886-2897. DOI: 10.1111/1750-3841.15779

[79] Adomavičiute E, Milašius R, Žemaitaitis A, Bendoraitiene J, Leskovšek M, Demšar A. Methods of forming nanofibres from bicomponent PVA/Cationic starch solution. Fibres and Textiles in Eastern Europe. 2009;**74**(3):29-33

[80] Silva I, Gurruchaga M, Goñi I, Fernández-Gutiérrez M, Vázquez B, Román JS. Scaffolds based on hydroxypropyl starch: Processing, morphology, characterization, and biological behavior. Journal of Applied Polymer Science. 2013;**127**(3): 1475-1484. DOI: 10.1002/app.37551

[81] Li S, Kong L, Ziegler GR. Electrospinning of octenylsuccinylated starch-pullulan nanofibers from aqueous dispersions. Carbohydrate Polymers. 2020;**258**:116933. DOI: 10.1016/j. carbpol.2020.116933

[82] Kong L, Ziegler GR. Role of Molecular Entanglements in Starch Fiber Formation by Electrospinning. Biomacromolecules. 2012;**13**(8): 2247-2253. DOI: 10.1021/bm300396j

[83] Martins A, Chung S, Pedro AJ, Sousa RA, Marques AP, Reis RL, et al. Hierarchical starch-based fibrous scaffold for bone tissue engineering applications. Journal of Tissue Engineering and Regenerative Medicine. 2009;**3**(1):37-42. DOI: 10.1111/j.1582-4934.2009.01005.x

[84] Stijnman AC, Bodnar I, Hans TR. Electrospinning of food-grade

polysaccharides. Food Hydrocolloids. 2011;**25**(5):1393-1398. DOI: 10.1016/j. foodhyd.2011.01.005

[85] Oktay B, Baştür E, Kayaman-Apohan N, Kahraman MV. Highly porous starch/poly(ethylene-altmaleic anhydride) composite nanofiber mesh. Polymer Composites. 2013;**34**(8): 1321-1324. DOI: 10.1002/pc.22545

[86] Estevez-Areco S, Lucas G, Roberto C, Silvia G. Active bilayer films based on cassava starch incorporating ZnO nanorods and PVA electrospun mats containing rosemary extract. Food Hydrocolloids. 2020;**108**(106054). DOI: 10.1016/j.foodhyd.2020.106054

[87] Pérez-Masiá R, Lagaron JM, López-Rubio A. Surfactant-aided electrospraying of low molecular weight carbohydrate polymers from aqueous solutions. Carbohydrate Polymers. 2014;**101**:249-255. DOI: 10.1016/j. carbpol.2013.09.032

[88] Valdespino-León M, Calderón-Domínguez G, Salgado-Cruz MP, Rentería-Ortega M, Farrera-Rebollo RR, Morales-Sánchez E, et al. Biodegradable Electrosprayed Pectin Films: An Alternative to Valorize Coffee Mucilage. Waste Biomass Valor. 2021;**12**: 2477-2494. DOI: 10.1007/s12649-020- 01194-z

[89] Tuzlakoglu K, Santos MI, Neves N, Reis RL. Design of nano- and microfiber combined scaffolds by electrospinning of collagen onto starch-based fiber meshes: A man-made equivalent of natural extracellular matrix. Tissue Engineering - Part A. 2011;**17**(3-4):463-473. DOI: 10.1089/ten.tea.2010.0178

[90] Rentería-Ortega M, Salgado-Cruz MDLP, Morales-Sánchez E, Alamilla-Beltrán L, Farrera-Rebollo RR, Valdespino LM, et al. Effect of

*Starch Biodegradable Films Produced by Electrospraying DOI: http://dx.doi.org/10.5772/intechopen.101150*

electrohydrodynamic atomization conditions on morphometric characteristics and mechanical resistance of chia mucilage-alginate particles. CYTA - Journal of Food. 2020;**18**(1):461-471. DOI: 10.1080/19476337.2020.1775706

[91] Gaona-Sánchez VA, Calderón-Domínguez G, Morales-Sánchez E, Moreno-Ruiz LA, Terrés-Rojas E, Salgado-Cruz MDLP, et al. Physicochemical and superficial characterization of a bilayer film of zein and pectin obtained by electrospraying. Journal of Applied Polymer Science. 2021;**138**(12):50045. DOI: 10.1002/ app.50045

[92] Rentería-Ortega M, Salgado-Cruz MDLP, Morales-Sánchez E, Alamilla-Beltrán L, Valdespino-León M, Calderón-Domínguez G. Glucose oxidase release of stressed chia mucilage-sodium alginate capsules prepared by electrospraying. Journal of Food Processing and Preservation. 2021;**45**(5):e15484. DOI: 10.1111/ jfpp.15484

#### **Chapter 10**

## Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based Polymeric Materials

*Doina Dimonie, Mircea Filipescu, Mihai Dragne, Alina Mustatea and Nicoleta Dragomir*

#### **Abstract**

The use of starch, the second most abundant natural resource in the word, as polymer is unprofitable and limited by certain functional properties. The structuring of multiphase polymeric materials represents the process of diminishing the dispersed phases till micro-and/or nano-dimensions and the positioning of the resulted fields in an order through which the properties of interest are achieved as far as possible. The structuring is reached by controlling the interface properties for achieving physical, chemical, biological or rheological compatibilization, mainly by melt compounding procedure. The chapter proves that the structuring of starchbased multiphases polymeric systems by reactive compatibilization is a good possibility to guarantee the functional properties, required by sustainable applications, of interest even in 2050 perspective. The chapter underlines also that the structuring by reactive compatibilization is connected with the formulation designing and choosing of the melt-compounding conditions in such a manner for the chemical bonding of the minority phases with the main polymeric matrix and therefore increasing the component miscibility and the functional properties of the resulted materials till the requirements of the sustainable applications.

**Keywords:** starch, multiphase polymeric systems, interface, reactive compatibilization, reactive extrusion

#### **1. Introduction**

After cellulose, starch is the second most abundantly available natural polymer in the world. Because of its biodegradability and non-toxicity to the natural environment, it becomes a raw material very attractive for the food and non-food application. Starch is a homo-polysaccharide made up of glucose units, linked together via glycosidic linkages, with a renewable-botanic origin (seeds and plant tubers), lowest price and highest industrialization potential for the next decade [1–13]. Starch has a

biphasic composition because consists in two polysaccharides, amylose with linear macromolecules and low molecular weight and amylopectin with branched, clustered chains which belong simultaneously to several clusteres and high molecular weight. Depending on its origin, the diameter of the starch granules varies between 1 and 2 μm to 100 μm. The starch granules are different shaped: round (corn), oval (potato), rounded and truncated at one end (tapioca), flat, elliptical (wheat) [4–9]. Because each starch is different in composition the obtained films could exhibit different properties [10].

The ratio between the two constituent polymers of starch conditions the subsequent use of starch as thermoplastic polymer, as during the melted state flowing, the amylose macromolecules align in the flow direction and because its chemical strongly branched macromolecules, those of amylopectin cannot be aligned. The ratio between amylose and amylopectin depends on the starch origin and the growing climatic conditions. Starch is a semi-crystalline polymer that does not melt in the traditional sense to form a liquid. Starch melting occurs in the presence of a moderate (10–30%·w/w) water content. Starch crystals contain about 9–10%·w/w of bound water, which does not freeze at cooling below 0°C. Additional water or plasticizers is required for melting of starch at convenient temperatures below the water boiling temperature and the starch degradation temperature [11]. Starch has multiple glass transitions under which physical aging occurs. Due to the high hydroxyl content, the starch properties are strongly dependent on the moisture.

Currently, on the market, there are varieties of commercially starch available (potato, corn, wheat, topioca, etc)and numbers of un-explored and under-utilization sources of starch (fruits processing waste, different agro-industrial residues, etc.) [12, 13].

Starch is an important source of raw materials both as organic compounds and polymer used for plastic industry. It can be converted readily into a variety of useful monomeric and polymeric products by chemical and biochemical routs. Fermentation of starch to industrial-grade ethyl alcohols becoming more economically competitive with the synthetic methods due, largely, to the increasing cost of ethylene. Other biological conversions yield a variety of alcohols, ketones, and organic acids, and these too will become increasingly important as the petroleum situation worsens. Enzymatic conversion of starch to glucose, a useful starting compound for a variety of alcohols, acids, and polyols, proceeds readily and in near quantitative yield. Glycol glucosides, cyclic polyols derived by glycolysis of starch, are excellent replacements for petroleum-derived polyols in the production of rigid urethane foams, and can replace up to 85% of petroleum-based polyols in alkyd resins with no loss in quality of the resin [14].

However, its use as a polymer is unprofitable and limited by certain functional properties. Its hydrophilicity, thermal, and mechanical properties limitations, low physical properties (brittle, poor moisture resistance, low permeability to lower gases, high density) rapid degradability, and strong intra and intermolecular hydrogen bonding of the polymer chains hinder its melt processability and limit its widespread commercial application as a renewable biopolymer [3, 15]. Starch also is easy degradable under flowing in the melted state. Moreover there are many difficulties in controlling the functional properties during its service life because of frequently occurred phenomena as exudation of plasticizers (anti-plasticization), re-crystallization (retrogradation) [7].

The perspective for polymeric materials based on renewable resources will be constantly increasing as far as 2050. Due to the failure in solving the issue of environment *Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

infestation with secondary polymeric materials, the development policies in designing and achieving polymers and materials based on them are mainly oriented towards sustainable applications.

In order to reach functional properties of practical interest including the sustainable applications, the multiphase starch-based systems are structured mainly by reactive compatibilization at melt processing (reactive extrusion) which has proven to be the most effective method. That is why the chapter presents the possibilities to get new starch-base, multiphase materials proving that structuring based on reactive compatibilization are adequate and practical solutions to ensure functional properties for durable applications. The chapter presents the main possibilities of structuring multiphase systems based on starch and details certain aspects related to the compounds of starch with polyvinyl alcohol.

#### **2. Structuring the multiphase polymeric materials**

Multiphase polymeric materials are homogeneous or non-homogeneous systems which contain solid, liquid or gaseous phases and include categories as: composites, blends, gels, interpenetrated polymer networks, mono or layered structure, cellular solids (foams), including biological type (hydrogels) etc. [16, 17]. The dispersed phases into the polymeric matrix can be functionalized, microencapsulated, oriented, continuous or discontinuous, etc. [16–19].

The structuring of multiphase materials represents the process of diminishing the dispersed phases till micro-and/or nano-metric scale and the positioning of the resulted mico and/or nano fields in an order in which, the properties of interest are achieved as far as possible. The structuring consists in enhancing by controlling the interface properties the physical-chemical-biological-rheological compatibility of the blend components considering methods connected with mobility of the segments/ macromolecules/morphological elements, or with reactivity of the components or/ and with ordering of the flowing elements at melt compounding [16–18].

The structure-properties relationship has a crucial significance in the structuring of the multiphase polymeric materials for developing grades satisfying varied engineering requirements [18, 19]. With the help of modern technologies, the circumstances in which the phases of the heterogeneous polymeric materials can be so arranged to give the desired properties in correlation with the intended applications, is possible to be identify.

The interfaces adhesion between the dispersed phases and polymeric matrix are maintained by intermolecular physical or chemical forces and/or by chain entanglements [20]. In the absence of these interactions, the interface becomes the place where the brittle fracture takes place. The interface can be seen as a resistance between materials in contact and is characterized by interfacial tension (controlable by changing of the Gibbs potential per unit area). The interfacial tension depends on factors such as: phases geometry (shape, average size, particle size distribution, porosity, etc.), the characteristics of macromolecular chains (molecular structure, molecular architecture, tacticity, crystallinity, ramifications and/or, defects, impurities, ash), the size of thermo-mechanical stress, the melt flow features (the size of mechanical stress, temperature) [16, 21–25]. Most thermodynamic studies of multiphase polymer systems are based on Flory-Huggins' theory [26].

Changing the interface properties have the effect the modification of the material properties. The least common possibilities encountered in the practice of polymer

blends achieving are those in which the compound properties are synergistic, i.e. the blend properties are greater than the additive properties of the individual polymers. The properties are synergistic for polymers showing high interface adhesion denoting that they are thermodynamically compatible [17, 27, 28]. The most common dependence blends properties - composition is the additive those, when the blend properties represent the average of the component properties in their pure state, without minimum or maximum. If the interfacial adhesion is very weak and the polymers are thermodynamically incompatible, this dependence does not follow the law of additivity, but shows a variation with a minimum, which means that the blend properties are lower than those of each individual components [17, 28].

Compatibilization is the process of modifying the properties of the interfaces in immiscible polymeric systems which results in the creation of the interphase region in which a gradient of material composition is created [20]. By compatibilization the morphology of the new material is stabilized at macroscopic level and therefore, the functional properties are constant over lifetime. The degree of compatibility is estimated by the thickness of the interface, the size of the dispersed phases, the mechanical performances generally by all functional properties. Unlike the compatibility, the miscibility is related to the blending of components at the molecular level; in the whole mass, which means that in the case of miscible blends it is no longer about dispersed phases [20, 29].

In order to improve the compatibility, the problem of minority components dispersing into the majority polymeric matrix is solved by reducing the interfacial tensions using one of the following techniques: entanglement of the macromolecules, interpenetration of interfaces, development of chemical (covalent linkages) or physical (e.g.van der Waaals, hydrogen bonds, ionic interactions, etc.) bonds [22]. The entangled interfaces are found in miscible blends or composites with good interfacial adhesion. The interfacial tension can be controlled by using polymeric emulsifiers (grafted or block copolymers, others) which create secondary bonds or by using compatibilizers, which generate chemical bonds between phases, after reactions possible between several functional groups (anhydride-amine, epoxyanhydride, oxazoline-carboxylic acid, isocyanate-carboxylic acid, lactic acid-amine, carbodiimides-carboxylic acid, ion exchange reactions, free radical grafting reactions at the phase interface [17]. By using a controlled method to improve the compatibility even miscibility between the components of a new multiphase polymeric materials is possible to achieve materials, with own functional properties correlated with requirements of various applications.

In case of multiphase polymeric materials with target fillers, the improving of compatibility is based also on the creating of physical and/or chemical bonds. If the cohesive energy thus developed is below a critical value, then morphological defects are created, between the filler and matrix, representing space filled with air, usually found as micro-voids, voids, macro-voids, cracks, fractures. The characteristics of the empty space depend on the shape of the filler. The cohesive energy may be below a critical value, situation in which the miscibility between the components is weak and/ or when the distribution of the filler into the matrix is inadequate. In the engineering practice, there are no free-defects multiphase materials such as the mentioned those it was found that if the content of these defects is higher than 5%, then the material functional properties decrease with approx. 30%. The structural defects presence is dangerous because, under stress, it accelerates the mechanical destruction by cracking and breaking [30, 31]. A filler can act also as compatibilizer when the radius of the particle has the same order of size as the radius of gyration [32].

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

**Figure 1.**

*Structuring melts by flowing in elongational (a) or shear stress field (b) [17, 33].*

Changing the interface properties has as effect the adjusting of the polymeric system properties. The least common possibilities encountered in the preparation of polymer blends are those in which the dependence of compound property-composition is "synergistic", i.e. the blend properties are greater than the additive values of the properties of individual polymers. The properties are synergistic only in case of the polymers showing high interface adhesion which means they are thermodynamically compatible [17, 27, 28]. The most common dependence blends properties—composition is the "additive" those, when the properties of the blend represent the average of the properties of its components in their pure state, without minimum or maximum. If the interfacial adhesion is very weak and the polymers are thermodynamically "incompatible", this dependence does not follow the law of additivity, but shows a variation with a minimum, denoting that the blend properties are lower than those of each individual components [17, 28].

The quality of items obtained by melt processing techniques, expressed as morphological uniformity, anisotropy of properties, appearance of surfaces, etc. depends on the structuring under stress of the flow entities in the field of mechanical and thermal stresses. Structuring under stress is the result of the molecular disaggregation, deformation, orientation, extension of macromolecular chains developed when the melts in passing through the nozzle of the nozzle of the molder device (**Figure 1**) [3, 33].

The flow resistance of the polymeric melts, a parameter which control the structuring during the melt compounding flowing, depends both on the shear rates and the molecular parameters describing the chemical structure of the polymeric blends components [34]. As an effect of the order degree gained during the melts flow through the nozzles is the crystallization under stress [33].

In order to deepen the structuring phenomena, the elucidation of the correlation between the molecular parameters (degree of polymerization, Flory-Huggins interaction parameters, etc.) and macroscopic phase separation phenomena is necessary to be done by investigating the heterogeneous structure from submicron scale to nanometer those [35].

#### **3. Structuring of starch based materials**

To get functional properties of wide applicability, starch can be converted into multiphase polymeric compounds, by physical and / or physical-chemical and/or chemical modification with other polymers and/or non-polymeric materials [36]

considering un-reactive and/or reactive melt compounding [25, 37–40]. Generally speaking, starch has low compatibility with other polymers or biopolymers and therefore the degree of compatibility varies depending on the specific used grades. The success of the starch converting into such multiphase polymeric systems is conditioned by the achievement of the molecular miscibility or, at least, by the creation of an advanced dispersion of minority components into the main polymeric matrix, via lowering the interfacial tensions considering the described compatibilization techniques [24, 41–43].

The convertion of starch into multiphases polymeric compounds of practical interest must consider both the starch origin, the ratio between the amylose and amylopectin, the constancy of this ration (especially for scaled up procedures), the correlation of the modification method with all the starch structural characteristics and the requirements of the considered application. The structuring possibilities are related equally to the way of designing the formulation and choosing of the melt compounding conditions the chapter presenting examples regarding the starch-polyvinyl alcohol compounds. An overview of the reactive compatibilization as method to get structured multiphase materials based on starch with other polymers is also given. A special attention is paid to the possibilities of avoiding the melt degradability of the multiphase systems based on starch. The chapter details also the structuring methods to achieve starch - PVOH nanocomposites with layer silicate content and presents a silicate treatment method which leads to the formation of exfoliated nanocomposites. The structuring through incorporation of a gaseous phase into the starch-starch matrix is also shortly described.

#### **4. Structuring through melt compounding**

Starch can be compounded with renewable polymers from *algal origin* (alginates); *microbial origin* (polysaccharides: chitosan, curdlan, gellan, pullulan, xanthan, bacterial cellulose; polyesters and copolyesters: polyhydroxyalcanoates (PHA), poly (butylene adipate-Co-terephthalate) (PBAT)); *plant origin* (polysaccharides: cellulose, pectin; proteins: soy proteins, zein, gluten: polyesters (polylactic acid PLA)); *animal origin* (polysaccharides: chitin, chitosan) [44, 45]. On the market there are also of interest starch compounds biodegradable or water- soluble oil-based polymers as: polycaprolactones (PCL), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA) or polyvinyl alcohol (PVOH) [46].

Starch compounds with PVOH are designed for replacement of LDPE films in application where barrier properties are not critical, water-soluble laundry bags, biomedical and clinical fields, replacement of polystyrene foams as loose fill packaging materials, packaging applications. Blending of starch with other biodegradable polymers such as biodegradable polyesters; polylactic acid (PLA) and polycaprolactone (PCL), was recognized as a successful strategy to provide a renewable, fully biodegradable and cost-effective materials [47]. The compounds of starch with PLA are conceived for applications as food packaging, electronic devices, membrane materials (chemical and automotive industries), medical applications, packaging materials. The compounds of starch with PBSA are useful as antimicrobial packaging materials and those with PHB as biomaterial in medical applications. PBAT starch compounds have controllable mechanical properties and are therefore are designed for multiple types of packaging [48]. The use of starch in achieving of polyurethane (PU) multiphase materials not only yields PUs with outstanding mechanical properties but also

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

makes the final PU products biodegradable. The hydrophilic nature of starch limits its dispersion in hydrophobic PU polymers [49] and therefore these compounds must be reactively compatibilized.

Renewable fillers play a valuable role in the development, of new multiphase polymer materials based on starch considering melt compounding techniques. It should be noted that the degree of compatibility between starch and other biopolymers extensively varies depending on the specific biopolymer, generally starch having as has been said low compatibility with other polymers [43, 50].

#### **4.1 Melt compounding conditions**

Starch can be melt compounded considering various conventional processing techniques, similar to those widely used for typical synthetic thermoplastics, such as extrusion, injection, compression molding, casting and foaming, as well as some new techniques as melt reactive melt compounding. Various starch-based products which have been developed and commercialized as extruded films/sheets, foams, shaped articles, etc. [51] using internal mixer, mono (**Figure 2**) or twin-screw extruders, injection devices, others can be obtain [52]. Formulations often require inlets for plasticizers, filler or other additives. Escape of volatiles such as steam will be required, without loss of other materials. High shear is required to disrupt the native starch structure and produce a uniform composition with other components. The extrudate must be a uniform continuous stream with rheology suitable for shaping [11].

A twin-screw extruder has a large operational flexibility (individual barrel zone temperature control, multiple feeding/injection, and screw configuration for different degree of mixing/kneading) and is useful for intensive mixing and compounding of components into starch plastics. In a twin-screw extruder the custom combinations of rheological elements can be assembled along the screw. Zone of high shear will assist with disruption of granules while uncoiling of molecules can take place in less shear intensive zones. Another advantage of the twin-screw extruder is to allow the decoupling of die flow and mechanical treatment. During extrusion of starch-based multiphase materials, residence times and specific mechanical energy inputs must be controlled, and high efficiency production can be achieved [52]. The temperature conditions for preparation and processing of these materials must be chosen to minimize possible degradation of the organic modifier and the matrix [53–55]. The shear experienced during compounding may have caused fragmentation of starch and destroyed its crystalline structure [56]. Shearing of the molten granules destroys their organized structure, and crystalline, granular starch is converted to a dispersed, essentially amorphous material [57]. It was found that if the extrusion is performed at

**Figure 2.** *Schematic representation of starch processing by extrusion [52].*

high rotational speed and high stationary times the single helix crystallites are formed [58, 59]. Also during extrusion the shear stress may enhance starch separation, whereby amylose may be partly leached out of the amylopectin [60, 61].

Because the melt compounding conditions control the melt rheological properties they have a great impact on the properties of the resulted compounds [42, 52]. In [42] it has been shown that for the polymeric compounds sensitive to the melt processing parameters, such as those based on starch, the boundary between miscible and less miscible is very small and therefore each compounding ratio requires its own formulation and its own melt flow conditions. It was shown that the miscibility of starch-based compounds increases if, for each formulation is found the melt processing conditions which ensure the better improving of miscibility because the melt resistance to flow allows a suitable homogenizing without degradation of the macromolecules (**Figure 3**).

The starch-PVOH compounds designed for short life application which had enhanced miscibility achieved by controlling the melt resistance to flow via melt compounding conditions have a better surface appearance (**Figure 4**) and no longer presents the anti-plasticization and retrogradation phenomena [42].

**Figure 3.**

*Dependence of the shape of the FTIR spectra (a) and of the XRD diffractograms (b) and the SEM micrographs aspect (fracture) of some starch-PVOH compounds (c) on the melt compounding conditions [42].*

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

#### **Figure 4.**

*Morphology (fracture, 1000×) (a, b) and surface appearance (c, d) before (c) and after (d) improving the miscibility via controlling the melt resistance to flow of some starch-PVOH compounds [42].*

#### **Figure 5.**

*Granules (20–70% starch content) and items achieved from PVOH-starch compounds after elimination of defects via structuring by controlling the melt resistance to flow [17, 63].*

It was observed that the starch polymer melts exhibit strong elastic properties and therefore phenomena as nozzle swelling, shark skin and wall slip [62] can be controlled. The experimental results have shown that these phenomena can be avoided by controlling the elastic component of the melt vasco-elastic properties considering the formulation and the selection of optimal compounding conditions. In this way the PVOH-starch compounds can be melt processed into items without defects and degradation, with natural color, smooth surface (**Figure 5**) and functional properties of interest for short-life applications [17, 63].

#### **5. Solid state properties conditioning the structuring efficiency**

#### **5.1 The polymers particles shape and size influence**

In [64] was found, that the turning of corn starch via melt compounding with PVOH can be achieved by providing similar melting behavior of the starch and of PVOH powder and by controlling the process sensitivity of the new compounds. The corn starch and PVOH particles had their own size distribution and shape. If the starch particles were rectangular, those of PVOH were spherical [64]. The PVOH particles shape depends on the manufacturing technology and can be spherical only if the polymer was obtained by reverse suspension hydrolysis of poly (vinyl acetate) (PVA) [65]. It has been shown that the particles of the two polymers cannot be melt compounded than after the selection of fractions with particle size variable the same range. If the particle size distribution of the two polymers is wide, then the obtained compounds include defects, either rough surfaces or un-melted inclusions. Variable sized particles have distinct melting times, longer for those with larger diameter and smaller for those with smaller diameter. The rough surface results due to the degradation of small particles and solid inclusions represent un-melted particles because they had large diameter and have no time to melt. Due to the variation of the particle sizes

of the two polymers even the morphologies of the achieved compounds and their dynamo-mechanical properties are affected (**Figures 6** and **7**). If the particles of the two polymers have approximately the same size then they melt in approximate identical time and the two type of defects are avoided.

In addition, if the blends obtained through melt compounding of starch with PVOH contains un-melted particles, then morphological defects such as voids, cracks fractures, may appear around them (**Figure 6**), The new compounds always will contain, near un-melted particles because of their size, parts from the starch grains, representing the branched macromolecules of amylopectin, very well visible on the SEM micrographs.

#### **Figure 6.**

*Morphological defects of the compound achieved from starch with 40–63* μ*m sized particles and PVOH with particles of 80–100* μ*m (1/1 blending ratio) [64].*

#### **Figure 7.**

*The dependence of the dynamo-mechanical properties of the starch-PVOH compounds (storage modulus (a), loss modulus (b)) on the temperature and the particle size (1—P1 (80–100* μ*m)/P2 (80–100* μ*m); 2—P1 (80–100* μ*m)/P2 (100–200* μ*m); 3—P1 (80–100* μ*m)/P2 (200–300* μ*m); 4—P1 (63–80* μ*m)/P2 (80–100* μ*m); 5—P1 (63–80* μ*m)/P2 (80–100* μ*m)) [64].*

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

Considering the word "compatibility" describing the partial miscibility of the compounds components which result in macro-metric scale time stability of the obtained compounds, appropriate for the life-time, the term "miscibility" reflects the interpenetration of the components at the molecular level and so stability for an unlimited period for the new materials [64]. It can be appreciated that the polymeric particles, through their size, make the differences even between compatible and miscible compounds. In analyzing the compatibility/miscibility between starch and PVOH compounds (claimed compatible by some authors and opposite by others) the influence of the particles size and of the amylopectin content should be equally considered. In accordance with [64] the starch-PVOH compounds obtained from small sized particles are close to be totally miscible, presenting a single glass transition without shoulders, totally different as those of starch and PVOH beeing almost a continuous phase, only with few defects as voids etc. In the last period, on the commercial market, can be found grades of thermoplastic starches which represent plasticized starch powder melt processed into granules.

#### **6. Structuration through reactive compounding (***in situ* **compatibilization)**

The experimental practice has shown that only physical compatibilization which establishes only secondary bonds between the dispersed phases and the matrix does not generate functional properties of practical interest. As it has been pointed out, because of poor interactions, starch is generally thermodynamically immiscible with all renewable polymers showing a dispersed structure (ex. ternary blends based on PCL/starch/PLA, starch-PBAT [66]. Structuration through reactive compounding (*in situ* compatibilization or chemical compatibilization) involves the development, in the melted state, during compounding, of chemical reaction between the functional groups of the compatibilizer and those of the starch and the second polymer from the compounds. The process involves the *in-situ* formation of amphiphilic structures, and thus covalently bonding the phases in the melt state. Reactive melt compounding is a convenient and cost-effective technique for the esterification of polysaccharides using anhydride reagents In this way the interface tension decreases, the size of the dispersed phases decreases and the functional properties can be controlled [67, 68]. The chemical compatibilization is relevant when morphology present regions with fully continuity or presents a co-continuous aspect.

To understand the lack of affinity between the different phases, interface adhesion can be investigated by contact angle measurements. The compound morphology can be better observed using microscopy techniques (e.g. SEM, etc.) The rheological investigations in solid (DMA) and melted state helps to understand better the blend structure formation during the process [69]. Currently, nanofillers are used to improve both mechanical properties and the phase morphologies of immiscible blends. The main advantage of using nanofillers, when compared to copolymers, is that the former can simultaneously act as nano-reinforcements and compatibilizers [67]. There are situations when the reactive compatibilizers can fulfill other functions such as antibacterial agent [70].

Twin-screw extruders are typically used for reactive compounding due to their excellent control of mixing, temperature, and residence time distribution, with highly accurate feeders, systems for removal of reaction heat, etc. [71–75].

Because of interest for industrial quantities of compatibilized multiphase renewable polymeric materials and the possibility to ensure functional properties of practical interest for desired applications, the chemical compatibilization strategy is usually implemented in reactive melt processing procedure (reactive extrusion) [71]. The concrete reactive compatibilization solution depends on the nature of the renewable multiphase polymeric system which must be structured [76–78].

#### **7. Structuring by incorporating layered silicates**

Polymeric nanocomposites have achieved much more attention due to their enhanced physic-chemical and mechanical properties, improved moisture sensitivity in comparison to the pure polymers. Due to its chemical and physical properties, starch is highly valuable to be structured through converting into nano-composites considering melt compounding procedures (twin screw extruder) including the reactive melt processing [79, 80].

Various types of nano-fillers that have been used with plasticized starch can be used such as montmorillonite, cellulose nano whiskers, cellulose nano-fiber, and starch nano-particles (obtained by acidic hydrolysis of waxy maize starch granules as reinforcement [81]). The starch-based nano-composites with different nanofillers for reaching a optimal dispersion and properties need particular preparation strategy [82–85]. The incorporation of various fillers in a starch-based polymer matrix generates specific structuring process because in this situation they control the specific orientation and/or crystallization processes.

For getting starch-based nano-composites, blends of starch with bio-polyesters or other renewable- or synthetic-based polymers can be used, e.g. which can be considering various obtaining procedures [86].

Regarding the achieving of the starch-PVOH nano-composites structured with layered silicates in a melt compounding procedure were studied aspects as: the dependence of miscibility, morphology and other functional properties on the layered silicate nature, the functionalization strategy of the galleries [87, 88] the target filler content [89], the incorporating method of the layered silicate into the starch matrix [90–92], the correlation between miscibility and the surface defects [31, 93]. At first sight, the dispersion of the layered silicate with the help of shear stress at melt compounding should favor the exfoliation process. In reality, this method is limited both by the low thermo-stability of the polymers and those of the used modifiers but also due to the loss of hydration water of the layered silicate consequence of long maintenance at high temperature in the compounding device. It was also found that, at the same target filler content, the size of the dispersed phase and the number of dispersed phases per unit area (drops) depend on the type of filler, nature of the surface treatment and particle size. It was concluded that the degree of intercalation of the layered silicate with the PVOH-starch matrix increases if purified layered silicate (NaMMT) or ammonium ion functionalized layered silicate (Nanocor I 28) are used to strengthen the STARCH-PVOH matrix. If, on a macroscopic scale (100 μ) the starch-PVOH-layered silicate compounds seem to be compact materials, at microscopic level (10 μ), defects as gaps, cracks, fracture etc. appear. These morphological defects seem to illustrate a disordered microstructure, due to the poor distribution of swollen silicate tectoids into the continuous polymeric phase, possibly due to inadequate compounding conditions. It has been shown that the PVOH-starch-treated layered

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

#### **Figure 8.**

*The swelling and exfoliation of NaMMT during a thermo-mechanical procedure applied before melt compounding (a—stirring without temperature; b—stirring with temperature) incorporation into a starch-PVOH matrix [91].*

silicate blends which, according to X-ray diffractograms, appear to be of exfoliated type and which have an improved thermal behavior, including in terms of uniformity of the melting process, have homogeneous surfaces and low material imperfections as gaps, cracks. SEM micrographs show that the surface of the compositions which, according to X-ray diffraction, are exfoliated intercalated nano-composites. Are characterized by small contact angle, are nano-structured, show advanced miscibility (demonstrated by FTIR analysis), have smaller number of defects as gaps, cracks, fractures [31, 87–93]. Compounds that, according to XRD diffractograms, are micro-structured, have frequent surface defects and irregular fracture areas, which are the starting points for cracking, crack propagation and stress rupture [31, 87–93].

In order to achieve a good swelling of the layered silicate and a homogeneous dispersion of the obtained lamellae into a starch-PVOH compound, it has been shown that, the layered silicate needs to be swelled, better in a pre-compounding procedure [91]. The layered silicate (NaMMT) was treated, before compounding in water, an effective starch and PVOH plasticizer. It was shown that the degree of exfoliation of the multilayer silicate and the properties of the achieved micro- and nano-composites depend on the way the silicate was treated (stirring of layered silicate at 1500 rpm, in water, at room temperature or at 50°C, for (8, 16, 24, 76, 288 h) (**Figure 8**). A small degree of silicate exfoliation reveals that the layered silicate was not sufficiently hydrated and therefore did not disperse well in water. If the silicate was treated an optimal time at room temperature or better at 50°C, a much shorter time, then the XRD diffractograms show the swelling of the NaMMT lamellae and even their exfoliation [91]. The obtained

**Figure 9.**

*Influence of silicate treatment on the surface appearance of a multiphase compound with 70% starch and 4% NaMMT (untreated (a), treated at 50°C, for 8 h (b) and treated for 24 h (c); starch particles (d) (SEM micrographs).*

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

results show that even for starch-PVOH compounds the target fillers, well selected and properly embedded, function as efficient interface agents.

If the surface appearance of the PVOH-starch composites containing untreated NaMMT is compared with that which enclosed pretreated silicate at 50°C for 72 h, reveals that for the latter, the surface defects and the included spherical shapes with well-defined interfaces are almost disappeared (see SEM micrographs from (**Figure 9**).

As consequence of the layered silicate de-lamination the storage modulus increases from 2 to 6 MPa, for the starch-PVOH compound without silicate, to 35–40 MPa, if the blend contains NaMMT stirred with water at 50°C, for 72 h. Depending on the characteristics of the applied treatment, starch-PVOH based micro- and/or nanostructured, intercalated and/or exfoliated nano-composites were obtained [91].

#### **8. Structuring by incorporating gaseous phase**

Depending on the dynamo-mechanical modules and the glass transitions, starch-PVOH formulations were selected for obtaining biodegradable structured foams of practical interest, with a compressive strength of 5–25 MPa and which supports compressions of 80–90%.


**Table 1.**

*Dependence of the storage and loss modulus on the starch content of the basic blend [17].*

**Figure 11.**

*Morphology of starch-PVOH based foams (a); shape and size of the starch particles (SEM micrographs) (b) [17].*

Biodegradable foams with variable starch content were made, with open pores of 2–3 mm, storage modulus 2–40 MPa, loss modulus of 2–8 MPa and which supports a compression deformation of 60–85% (**Figure 10** and **Table 1**) [17]. By using a proper foaming agent the density of the foam was reduced to 0.219–0.458 g/cm3 . The original composition was patented [17].

Depending on the amount of foaming gas appeared, the process involves, in its first phases, only the rupture of the continuous matrix in which the dispersed gas phase is placed (**Figure 11**) [94].

#### **9. Conclusions**


*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*


#### **Acknowledgements**

The work on this paper was supported by the Government of Romania, Ministry of Research and Innovation, Project funded by cohesion funds of the European Union Project: P\_40\_352, SECVENT 81/2016, "Sequential processes of closing the side streams from bioeconomy and innovative (bio) products resulting from it", Subsidiary project 1480/2019 and project supported the Romanian Ministry of Research and Innovation, CCCDI – UEFISCDI, project number no. 23N/2019.

#### **Conflict of interest**

The authors declare no conflict of interest.

### **Author details**

Doina Dimonie1 \*, Mircea Filipescu1 , Mihai Dragne2,3, Alina Mustatea2,3 and Nicoleta Dragomir1

1 National Institute for Research and Development in Chemistry and Petrochemistry-ICECHIM, Bucharest, Romania

2 "Applied Chemistry and Materials Science" Doctoral School, Politehnica University of Bucharest, Gheorghe Polizu, Bucharest, Romania

3 PROMATERIS SA, Bucharest, Romania

\*Address all correspondence to: ddimonie@yahoo.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

#### **References**

[1] Bos H, Elbersen W, Cadórniga Valiño C, Alexopoulou E. Market Demand for Non-Food Crops. 1998. Available from: http://www.cres.gr/ crops/pdf/wp6/Final%20Report%20 WP6%20Scenarios%20v%20 31-01-2011.pdf

[2] Elbersen HW, van der Zee M, Bos HL. The role of 4F crops in EU27 under contrasting future scenarios—Final report on WP6. November 2010. Available from: http://www.cres.gr/ crops/pdf/intranet-wp1/WP1\_D3\_ MARKETS.pdf

[3] Zarski A, Bajer K, Kapuśniak J. Review of the most important methods of improving the processing properties of starch toward non-food applications. Polymers. 2021;**13**:832. DOI: 10.3390/ polym13050832

[4] Mark JE. Polymer Data Handbook. New York: Oxford University Press, Inc.; 1999. ISBN: 0195107896 9780195107890

[5] McMurry JE. Organic Chemistry. Pacific Grove: Cole Publishing Co.; 1992

[6] Kim Y-K, Rudd ME. Binaryencounter-dipole model for electronimpact ionization. Physical Review. 1994;**50**(5):3954. DOI: 10.1103/ PhysRevA.50.3954

[7] Lee SY. Plastic bacteria? Progress and prospects for polyhydroxyalkanoate production in bacteria. Trends Biotechnology. 1996;**14**:431. DOI: 10.1016/0167-7799(96)10061-5

[8] Colonna P. La chimie verte. Paris: Editions TEC&DOC Lavoisier; 2005. ISBN 10: 2-7430-0834-2, ISBN 13: 978-2-7430-0834-5

[9] Struik LCE. Physical Aging in Amorphous Polymers and Other Materials. New York: Elsevier Scientific Publishing Company; 1978

[10] Wilfer PB, Giridaran G, Jeevahan JJ, Joseph GB, G. Kumar S, Thykattuserry NJ. Effect of starch type on the film properties of native starch based edible films. Materials Today: Proceedings. 2021;**44**(5):3903-3907. DOI: 10.1016/j.matpr.2020.12.1118

[11] Shanks, Robert & Kong, Ing. Thermoplastic Starch. 2012. DOI: 10.5772/36295

[12] Yazid NSM, Abdullah N, Muhammad N, Matias-Peralta HM. Application of starch and starch-based products in food industry. Journal of Science and Technology. 2018;**10**(2): 144-174. DOI: 10.30880/jst.2018. 10.02.023

[13] Nayak PL. Biodegradable polymers: Opportunities and challenges. Journal of Macromolecular Science. 1999;**39**:481- 505. DOI: 10.1081/MC-100101425

[14] Doane WM. Starch: Renewable raw material for the chemical industry. Journal of Coatings Technology. 1978;**50**(636):88

[15] Ojogbo E, Ogunsona EO, Mekonnen TH. Chemical and physical modifications of starch for renewable polymeric materials. Materials Today Sustainability. 2020;**7-8**. DOI: 10.1016/j. mtsust.2019.100028

[16] Boudenne A, Ibos L, Candau Y, Thomas S. Handbook of Multiphase Polymer Systems. John Wiley & Sons Ltd; 2011. ISBN:978-0-470-71420-1

[17] Dimonie D. Multipahase Polymeric Materials—Micro-and Nano-Structurated. Bucharest: Politehnica Press; 2019. ISBN: 978-606-515-893-1

[18] Barzic AI, Ioan S. Multiphase Polymer Systems. In: Micro- to Nanostructural Evolution in Advanced Technologies. CRC Press; 2019. ISBN: 9780367876531

[19] Harrats C, Thomas S, Groeninckx G. Micro- and Nanostructured Multiphase Polymer Blend Systems. CRC Press; 2005. ISBN: 0-8493-3734-8

[20] Work WJ, Horie K, Hess M, Stepto RFT. Definitions of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC recommendations). Pure and Applied Chemistry. 2004;**76**(11):1985-2007. DOI: 10.1351/pac200476111985

[21] Utraki LA. Polymers alloys and blends. State of art. Polymer Networks and Blends. 1991;**1**(2):61-69

[22] Utraki LA. Polymer blends technology. International Journal of Petroleum Science and Technology. 1994;**10**:125-133

[23] Fernandez ML. Demixing in polymer blends. Scientific Progress Oxford. 1990;**74**:257-277

[24] Stroble G. The Physics of Polymers: Concepts for Understanding their Structures and Behavior. Berlin, Heidelberg: Springer; 1996

[25] Hatsua I. Miscibility. In: Encyclopedia of Polymer Science and Engineering. John Wiley &Sons Inc.; 1989

[26] Boudenne A. Handbook of Multiphase Polymer Systems. Wiley; 2012. ISBN: 978-0-470-71420-1

[27] Tager AA, Blinov VS. Thermodynamic compatibility of polymers. Russian Chemical Reviews. 1987;**56**:579

[28] Paul DR. Polymer blends. Journal of Macromolecular Science Reviewers in Macromolecular Chemistry. 1980;**18**(1):109-168

[29] Garton A. Infrared Spectroscopy of Polymer Blends Composites and Surfaces. Carl Hanser Verlag, Munich Publishers; 1992. ISBN: 3-446-17136-3

[30] Malwitz MM, Lin-Gibson S, Hobbie EK, Butler PD, Schmidt GJ. Orientation of platelets in multilayered nanocomposites polymer films. Polymer Science part B Polymer Physics. 2003;**41**:3237

[31] Dimonie D, Kelnar I, Socoteanu R, Darie RN, Pop FS, Zaharia C. The influence of miscibility and microstructure on the surface defects of some starch bio-hybrides. Materiale Plastice. 2010;**47**(4):486-491

[32] Taguet A, Cassagnau P, Lopez-Cuesta JM. Structuration, selective dispersion and compatibilizing effect of nanofillers in polymer blends. Progress in Polymer Science. 2014;**39**:1526-1563. DOI: 10.1016/j. progpolymsci.2014.04.002

[33] Prentice P. Rheology and its role in plastics processing. Rapra. 1995;**7**(12):25

[34] Ralph H. Colby, melt viscositymolecular weight relationship for linear polymers. Macromolecules. 1987;**20**:2226-2237. DOI: 10.1021/ ma00175a030

[35] Takeo A, Qui T-C, Mitsubishi S. Structure and Properties of Multiphase Polymeric Materials. CRC Press; 1998. ISBN: 0-8247-0142-9

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

[36] Wu C-S, Liao H-T. Influence of a compatibilizer on the properties of polyethylene–octene elastomer/starch blends. Journal of Applied Polymer Science. 2002;**86**:1792-1798. DOI: 10.1002/app.11199

[37] Russell CA. Effect of stearate processing aids upon polypropylene stability. Polymer Engineering & Science. 1965;**5**(2):84-89. DOI: 10.1002/ pen.760050204

[38] Gachter R, Muller H. Plastics Additives Handbook: Stabilizers, Processing Aids, Plasticizers, Fillers, Reinforcements, Colorants for Thermoplastics. Vol. 754. United States of America: Oxford University Press; 1987. ISBN: 978-3446156807

[39] Sperling LH, Mishra V. Polymeric Multicomponent Materials. New York: Wiley-Interscience Publication, John Wiley & Sons Inc; 1997. pp. 1-25

[40] Mekonnen T, Mussone P. Progress in bio-based plastics and plasticizing modifications. Journal of Materials Chemistry A. 2013;**1**:13379-13398. DOI: 10.1039/C3TA12555F

[41] Dimonie D, Petrache M, Damian C, Anton L, Musat M, Dima Ş-O, et al. New evidences on the process sensitivity of some renewable blends based on starch considering their melt rheological properties. International Journal of Polymer Science. 2016:1-10. DOI: 10.1155/2016/7873120

[42] Dimonie D, Musat M, Doncea SM, Damian CM, Anton L, Vasile E, et al. Controlling the melt resistance to flow as a possibility of improving the miscibility and the time behavior of some blends based on starch. International Journal of Polymer Science. 2015:1-12. DOI: 10.1155/2015/582901

[43] Diyana ZN, Jumaidin R, Selamat MZ, Ghazali I, Julmohammad N, Huda N, et al. Physical properties of thermoplastic starch derived from natural resources and its blends: A review. Polymer. 2021;**13**(9):1396. DOI: 10.3390/ polym13091396

[44] Mironescu M, Lazea-Stoyanova A, Barbinta-Patrascu ME, Virchea L-I, Rexhepi D, Mathe E, et al. Green design of novel starch-based packaging materials sustaining human and environmental health. Polymers. 2021;**13**(8):1190. DOI: 10.3390/ polym13081190

[45] Encalada K, Aldás MB, Proaño E, Valle V. An overview of starch-based biopolymers and their biodegradability. Revista Ciencia e Ingeniería. 2018;**39**(3): 245-258

[46] Bangar SP, Whiteside WS. Nanocellulose reinforced starch bio composite films- A review ongreen composites. International Journal of Biological Macromolecules. 2021;**185**:849-860. DOI: 10.1016/j.ijbiomac.2021.07.017

[47] Bulatović VO, Mandić V, Grgić DK, Ivančić A. Biodegradable polymer blends based on thermoplastic starch. Journal of Polymers and the Environment. 2021;**29**:492-508. DOI: 10.1007/ s10924-020-01874-w

[48] Dammak M, Fourati Y, Tarrés Q, Delgado-Aguilar M, Mutjé P, Boufi S. Blends of PBAT with plasticized starch for packaging applications: Mechanical properties, rheological behaviour and biodegradability. Industrial Crops and Products. 2020;**144**. DOI: 10.1016/j. indcrop.2019.112061

[49] Tai NL, Ghasemlou M, Adhikari R, Adhikari B. Starch-based isocyanate- and non-isocyanate polyurethane hybrids: A review on synthesis, performance and

biodegradation. Carbohydrate Polymers. 2021;**265**:118029. DOI: 10.1016/j. carbpol.2021.118029

[50] Lopez-Gil A, Rodriguez-Perez MA, De Saja JA. Strategies to improve the mechanical properties of starch-based materials: Plasticization and natural fibers reinforcement. Polimeros. 2014;**24**:36-42. DOI: 10.4322/ polimeros.2014.053

[51] Jiang T, Duan O, Zhu J, Liu H, Yu L. Starch-based biodegradable materials: Challenges and opportunities. Advanced Industrial and Engineering Polymer Research. 2020;**3**(1):8-18. DOI: 10.1016/j. aiepr.2019.11.003

[52] Xie F, Halley PJ, Avérous L. Rheology to understand and optimize processibility, structures and properties of starch polymeric materials. Progress in Polymer Science. 2012;**37**(4):595-623. DOI: 10.1016/j.progpolymsci.2011. 07.002

[53] Pérez MA, Rivas BL, Rodríguez-Llamazares S. Polypropylene/ starch blends. Study of thermal and morphological properties. Journal of the Chilean Chemical Society. 2013;**58**: 1643-1646. DOI: 10.4067/ S0717-97072013000100030

[54] Xie F, Liu P, Yu L. Chapter 10— Processing of Plasticized Starch-Based Materials: State of the Art and Perspectives. In: Halley PJ, Avérous L, editors. Starch Polymers: From Genetic Engineering to Green Application. Elsevier; 2014. pp. 257-289. DOI: 10.1016/ B978-0-444-53730-0.00024-5

[55] Mahieu A, Terrié C, Agoulon A, Leblanc N, Youssef B. Thermoplastic starch and poly(ε-caprolactone) blends: Morphology and mechanical properties as a function of relative humidity. Journal of Polymer Research. 2013;**20**:229. DOI: 10.1007/s10965-013-0229-y

[56] Pushpadass HA, Bhandari P, Hanna MA. Effects of LDPE and glycerol contents and compounding on the microstructure and properties of starch composite films. Carbohydrate Polymers. 2010;**82**(4):1082-1089. DOI: 10.1016/j. carbpol.2010.06.032

[57] Matzinos P, Bikiaris D, Kokkou S, Panayiotou C. Processing and characterization of LDPE/starch products. Journal of Applied Polymer Science. 2001;**79**(14):2548-2557. DOI: 10.1002/1097-4628(20010401)79: 14<2548::AID-APP1064>3.0.CO;2-3

[58] Van Soest JJG, Vliegenthart JFG. Crystallinity in starch plastics: Consequences for material properties. Trends in Biotechnology. 1997;**15**(6): 208-213. DOI: 10.1016/S0167-7799 (97)01021-4

[59] Burmistrov VA, Lipatova IM, Losev NV, Rodicheva JA, Koifman OI. Influence of the composition and high shear stresses on the structure and properties of hybrid materials based on starch and synthetic copolymer. Carbohydrate Polymers. 2018;**196**:368- 375. DOI: 10.1016/j.carbpol.2018.05.056

[60] Liu H, Xie F, Yu L, Chen L, Li L. Thermal processing of starch-based polymers. Progress in Polymer Science. 2009;**34**(12):1348-1368. DOI: 10.1016/j. progpolymsci.2009.07.001

[61] Liu Y, Chen X, Xu Y, Xu Z, Li H, Sui Z, et al. Gel texture and rheological properties of normal amylose and waxy potato starch blends with rice starches differing in amylose content. International Journal of Food Science and Technology. 2021;**56**:1946-1958. DOI: 10.1111/ijfs.14826

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

[62] Giles HF, Wagner JR, Mount EM. Extrusion: The Definitive Processing Guide and Handbook. Plastics Design Library. Norwich, NY: William Andrew Pub; 2005

[63] Coserea RM, Dimonie D, Dimonie M, Hubca G. Some aspects concerning the rheology of biodegradable starch based materials. University Politehnica of Bucharest Scientific Bulletin Series B-Chemistry and Materials Science. 2012;**74**(2):37-48

[64] Dimonie D, Damian C, Trusca R, Rapa M. Some aspects conditioning the achieving of filaments for 3D printing from physical modified corn starch. Materiale Plastice. 2019;**56**(2):351-359

[65] Dimonie D, Petre D, Vasilievici G. Polyvinyl alcohol melt processing. Journal of Elastomers and Plastics. 2007;**39**:181-194. DOI: 10.1177/ 0095244306071978

[66] Fourati Y, Tarrés Q, Mutjé P, Boufi S. PBAT/thermoplastic starch blends: Effect of compatibilizers on the rheological, mechanical, and morphological properties. Carbohydrate Polymers. 2018;**199**:51-57. DOI: 10.1016/j. carbpol.2018.07.008

[67] Mochane MJ, Sefadi JS, Motsoeneng TS, Mokoena TE, Mofokeng TG, Mokhena TC. The effect of filler localization on the properties of biopolymer blends, recent advances: A review. Polymer Composites. 2020;**41**:2958-2979. DOI: 10.1002/ pc.25590

[68] Maliger RB, McGlashan SA, Halley PJ, Matthew LG. Compatibilization of starch–polyester blends using reactive extrusion. Polymer Engineering and Science. 2006;**46**(3):248-263. DOI: 10.1002/pen.20479

[69] Schwach E, Avérous L. Starch-based biodegradable blends: morphology and interface properties. Polymer International. 2004;**53**(12):2115-2124. DOI: 10.1002/pi.1636

[70] Davoodi S, Oliaei E, Davachi SM, Hejazi I, Seyfi J, Heidari BS, et al. Preparation and characterization of interface-modified PLA/starch/PCL ternary blends using PLLA/triclosan antibacterial nanoparticles for medical applications. RSC Advances. 2016;**6**:39870-39882. DOI: 10.1039/ C6RA07667J

[71] Imre B, García L, Puglia D, Vilaplana F. Reactive compatibilization of plant polysaccharides and biobased polymers: Review on current strategies, expectations and reality. Carbohydrate Polymers. 2019;**209**:20-37. DOI: 10.1016/j. carbpol.2018.12.082

[72] Hu H, Xu A, Zhang D, Zhou W, Peng S, Zhao X. High-toughness poly (lactic acid)/starch blends prepared through reactive blending plasticization and compatibilization. Molecules. 2020;**25**(24):5951. DOI: 10.3390/ molecules25245951

[73] Shin BY, Narayan R, Lee SI, Lee TJ. Morphology and rheological properties of blends of chemically modified thermoplastic starch and polycaprolactone. Polymer Engineering and Science. 2008;**48**(11):2126-2133. DOI: 10.1002/pen.21123

[74] Marinho VAD, Pereira CAB, Vitorino MBC, Silva AS, Carvalho LH, Canedo EL. Degradation and recovery in poly(butylene adipate-co-terephthalate)/ thermoplastic starch blends. Polymer Testing. 2017;**58**:166-172. DOI: 10.1016/j. polymertesting.2016.12.028

[75] Hwang SW, Shim JK, Selke S, Soto-Valdez H, Rubino M, Auras R. Effect of maleic-anhydride grafting on the physical and mechanical properties of poly (L-lactic acid)/starch blends. Macromolecular Materials and Engineering. 2013;**298**:624-633. DOI: 10.1002/mame.201200111

[76] Jang WY, Shin BY, Lee TJ, Narayan R. Thermal properties and morphology of biodegradable PLA/starch compatibilized blends. Journal of Industrial and Engineering Chemistry. 2007;**13**(3): 457-464

[77] Lendvai L, Brenn D. Mechanical, morphological and thermal characterization of compatibilized poly (lactic acid)/thermoplastic starch blends. Acta Technica Jaurinensis. 2020;**13**(1):1- 13. DOI: 10.14513/actatechjaur.v13.n1532

[78] Bher A, Uysal Unalan I, Auras R, Rubino M, Schvezov C. Toughening of poly(lactic acid) and thermoplastic cassava starch reactive blends using graphene nanoplatelets. Polymers. 2018;**10**:95. DOI: 10.3390/ polym10010095

[79] Madhumitha G, Fowsiya J, Mohana Roopan S, Thakur VK. Recent advances in starch–clay nanocomposites. International Journal of Polymer Analysis and Characterization. 2018;**23**(4):331-345. DOI: 10.1080/1023666X.2018.1447260

[80] Avella M, Vlieger JJ, Errico ME, Fischer S, Vacca P, Volpe MG. Biodegradable starch/clay nanocomposite films for food packaging applications. Food Chemistry. 2005;**93**(3):467-474. DOI: 10.1016/j.foodchem.2004.10.024. AGR: IND43721001

[81] García NL, Ribba L, Dufresne A, Aranguren M, Goyanes S. Effect of glycerol on the morphology of nanocomposites made from thermoplastic starch and starch

nanocrystals. Carbohydrate Polymers. 2011;**84**(1):203-210. DOI: 10.1016/j. carbpol.2010.11.024

[82] Xie F, Pollet E, Halley PJ, Avérous L. Advanced Nano-Biocomposites Based on Starch. In: Ramawat K, Mérillon JM, editors. Polysaccharides. Cham: Springer; 2014

[83] Hietala M, Mathew AP, Oksman K. Bionanocomposites of thermoplastic starch and cellulose nanofibers manufactured using twin-screw extrusion. European Polymer Journal. 2013;**49**(4):950-956. DOI: 10.1016/j. eurpolymj.2012.10.016

[84] Boonprasith P, Wootthikanokkhan J, Nimitsiriwat N. Mechanical, thermal, and barrier properties of nanocomposites based on poly(butylene succinate)/ thermoplastic starch blends containing different types of clay. Journal of Applied Polymer Science. 2013;**130**:1114-1123. DOI: 10.1002/app.39281

[85] García NL, Ribba L, Dufresne A, Aranguren MI, Goyanes S. Physicomechanical properties of biodegradable starch nanocomposites. Macromolecular Materials and Engineering. 2009;**294**:169-177. DOI: 10.1002/ mame.200800271

[86] McGlashan SA, Halley PJ. Preparation and characterisation of biodegradable starch-based nanocomposite materials. Polymer International. 2003;**52**:1767-1773. DOI: 10.1002/pi.1287

[87] Vasile C, Stoleriu A, Popescu M-C, Duncianu C, Kelnar I, Dimonie D. Morphology and thermal properties of some green starch/poly (vinyl alcohol) / montmorillonite nanocomposites. Cellulose Chemistry and Technology. 2008;**42**(9-10):549-568

*Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based… DOI: http://dx.doi.org/10.5772/intechopen.101166*

[88] Dimonie D, Radovici C, Vasilievici G, Popescu MC, Garea S. The dependence of the XRD Morphology of some bionanocomposites on the silicate treatment. Journal of Nanomaterials. 2008;**2008**:1687-4110. DOI: 10.1155/2008/538421

[89] Dimonie D, Radovici C, Zaharia C, Vasilievici G, Stoleriu A. Comportarea termica a nanocompozitelor biodegradabile pe baza de alcool polivinilic si amidon. Materiale Plastice. 2006;**43**(2):132-137

[90] Dimonie D, Radovici C, Trandafir I, Pop FS, Dumitru I, Fierascu R, et al. Some aspects concerning the silicat delamination for obtaining polymeric bio-hybrids based on starch. Revue Roumaine de Chimie. 2011;**56**(7):685-690

[91] Dimonie D, Radovici C, Pop FS, Socoteanu R, Petre C, Fierascu R, et al. Approaches considering a better incorporations of multylayers silicate into a polymeric matrix designed for bio–nano–materials obtaining. Nonlinear Optics, Quantic Optics: Concept in Modern Optics. 2012;**44**(2-3):137-148

[92] Dimonie D, Socoteanu R, Doncea SM, Pop FS, Petrea C, Fierascu R, et al. Miscibility estimation of some blends based on starch. E-Polymers. 2011;**11**(1):957-970. DOI: 10.1515/ epoly.2011.11.1.957

[93] Dimonie D, Kelnar I, Duncianu C, Coserea RM, Pop FS, Dumitriu I, et al. Some aspects concerning the surface defects of green nanocomposites based on renewable resources. In: Proceeding of 16th Romanian International Conference on Chemistry and Chemical Engineering (16th RICCCE); September 9-12. Sinaia: Ed. Printech; 2009. ISBN 978-606-521-349-4

[94] Dimonie D. RO Compozite biodegradabile, pentru ambalaje nealimentare si procedeu de obtinere a acestora. Patent No. 121692/28.02.2008

#### **Chapter 11**

## Starch-Based Hybrid Nanomaterials for Environmental Remediation

*Ashoka Gamage, Thiviya Punniamoorthy and Terrence Madhujith*

#### **Abstract**

Environmental pollution is becoming a major global issue with increasing anthropogenic activities that release massive toxic pollutants into the land, air, and water. Nanomaterials have gained the most popularity in the last decades over conventional methods because of their high surface area to volume ratio and higher reactivity. Nanomaterials including metal, metal oxide, zero-valent ions, carbonaceous nanomaterials, and polymers function as adsorbents, catalysts, photocatalysts, membrane (filtration), disinfectants, and sensors in the detection and removal of various pollutants such as heavy metals, organic pollutants, dyes, industrial effluents, and pathogenic microbial. Polymer-inorganic hybrid materials or nanocomposites are highly studied for the removal of various contaminants. Starch, a heteropolysaccharide, is a natural biopolymer generally incorporated with other metal, metal oxide, and other polymeric nanoparticles and has been reported in various environmental remediation applications as a low-cost alternative for petroleum-based polymers. Therefore, this chapter mainly highlights the various nanomaterials used in environmental remediation, starch-based hybrid nanomaterials, and their application and limitations.

**Keywords:** environmental remediation, hybrid nanomaterials, nanomaterials, starch, starch-based hybrid nanomaterials

#### **1. Introduction**

Environmental pollution is becoming a serious global problem that society faces today. Ongoing anthropogenic activities, extensive food and agriculture practices, industrialization, and urbanization release huge amounts of pollutants into the environment that can cause air, water, and land pollution, consequently threatening to human, animal health, and ecosystem [1, 2]. These toxic pollutants can enter the human body either through inhalation, ingestion, or absorption and adversely affect health. Further, bioaccumulation of some heavy metals through the food chain and persistent organic pollutants in biota and fishes poses a huge threat to humans and wildlife and requires sustainable, efficient, and low-cost technologies to detect, monitor, and remediate the hazardous pollutants [1].

Different forms of pollutants are released into the environment; soil, water, and air. Organic substances (pesticides, insecticides, fertilizers, oil spills, phenols, chloroform, hydrocarbons), heavy metals and metalloids (Cr2+, Pb2+, Co2+, Cd2+, Cu2+, Zn2+, Mn2+, Ni2+, As, Hg), dyes, industrial effluents, sewage, as well as microbial pathogens are few contaminants in soil and water. While, contaminants such as toxic gases (nitrogen oxides, sulfur oxides, carbon oxides, ozone), suspended airborne particles, and volatile organic compounds are found in the atmosphere [3, 4].

These contaminants in soil, water, and air are remediated by using different conventional techniques, such as physical, chemical, and biological methods [4–6]. These techniques may be used in combination with one another to remediate contaminated sites. Adsorption (clay minerals, industrial wastes, biomass, biochar, activated carbon, biopolymer), chemical treatments, bioremediation, coagulation and flocculation, ion exchange, membrane-filtration, solidification/stabilization, electrokinetics, and electrochemical treatments technologies have been used in heavy metal removal from soil and water [7]. Bioremediation using microorganisms and plants helps to detoxify or remove crude oil, heavy metal removal, and pesticide degradation from soil and water [4, 5].

However, the majority of these conventional techniques are expensive, laborious, environmentally destructive, time-consuming methods, also involved in the consumption of chemicals and the generation of undesirable toxic by-products that are hazardous to the environment. Further, complexities of the mixture of different compounds, high volatility, and low reactivity of contaminants also limit the applications in environmental remediation [3, 5, 8]. New environmental remediation technologies are constantly being explored, and recent studies have focused on developing new environmental remediation technologies using various nanomaterials [3].

#### **2. Nanotechnology in environmental remediation**

#### **2.1 Nanotechnology and its advantages and applications**

Nanotechnology has gained much attention in environmental remediation over the last few decades [1]. Nanotechnology is an advanced technology that works on the material in nanometer scale (1–100 nm) and produces materials, devices, and systems with specific and novel properties and functions by controlling the size and the shape of matters [1, 4, 9]. The nanomaterials are broadly categorized as organic and inorganic nanomaterials. Some literatures is classified based on materials used in the synthesis process; inorganic (metal, metal oxide, zero-valent metals), carbon-based [graphene, carbon nanotubes (CNTs)], polymer-based (dendrimers or polyamidoamine), and composite based nanomaterials [3, 10].

Nanomaterials have several advantages in environmental remediation over conventional methods; cost-effective, simple to use, energy conservative, sustainable, and more effective methods. Due to the properties such as smaller size (1–100 nm) and higher surface area to volume ratio of nanomaterials, they provide more reaction surface area, which increases reactivity and thus its sensitivity and effectiveness. Nanoparticles have a high sorption capacity for inorganic and organic compounds because of their specific characteristics; large surface area, an increased number of surface activation sites, a good affinity to other species [11]. Further, nanotechnology helps in the development of remediation technologies that are specific and efficient for a particular pollutant [3, 9].

#### *Starch-Based Hybrid Nanomaterials for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.101697*

Nanotechnology has potential applications in many fields, including food and agriculture, packaging, pharmaceutical, drug delivery, energy, and pollution treatment [1, 12]. Of which, the application of nanotechnology in pollution control and environmental remediation has gained popularity over the last decade; wastewater treatment, cleaning groundwater, and remediation of soil contaminated with pollutants. In the field of environment, nanotechnology has been used in pollution detection (sensing and detection), prevention of pollution, and purification/remediation of contamination [9]. Thus, nanotechnology provides a sustainable solution to the global challenges of protecting water, soil and providing cleaner air [13].

#### **2.2 Nanomaterials in environmental remediation**

Various nanomaterials such as inorganic, carbonaceous nanomaterials, polymerbased nanomaterial are used in environmental remediation (air, soil, and water) as adsorbents, catalyst, photocatalyst, membrane (filtration), disinfectants, and sensors [1, 3, 14].

Metal (silver, gold), metal oxides (iron oxides, TiO2, MgO, Fe2O3, Al2O3), and zero-valent metals (Fe0 , Zn0 , Sn0 , and Al0 ) based nanoparticles are mostly studied for environmental remediation including disinfection of water, treatment of drinking water, groundwater, wastewater, and air, because of their adsorption, antibacterial, antimicrobial, photocatalytic, reductive dehalogenation, desulfurization, and catalytic reduction activities [3, 15, 16]. Carbonaceous materials in different structural configurations; fullerene, single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and graphene and used in the removal of organic and inorganic contaminants from air and water due to its adsorption and photocatalytic property [3].

Nanoscale zero-valent iron (nZVI) is the most widely studied nanoparticle in soil remediation [12] and is used for reductive immobilization of heavy metals in soil that decreases the bioavailability and mobility of heavy metals and prevents leaching into groundwater and transfers to the food chain [1]. Further, nanomaterials such as nanoparticles (NPs) (metal; Au, Ag, Fe, bimetal; Fe/Ni, Ag/Cu, metal oxides; TiO2, ZnO, Fe2O3), nanotubes (carbon nanotubes, halloysite nanotubes), and nanocomposites (graphene oxide) have been reported to utilize in detection, degradation, and removal by adsorption of pesticides [17].

Emission of greenhouse gases (carbon dioxide, methane, nitrous oxide, and fluorinated gases), volatile organic compounds (ethylene, aniline, benzene), are controlled either by separation or capturing, such as filtration, absorption in liquids, adsorption on solids, or a combination of these processes. In addition, bioaerosols (aerosols of biological origin such as viruses, bacteria, and fungi), an indoor air pollutant, can rapidly spread with airflow and can cause numerous diseases, including infections and allergies. The air filtration process using antimicrobial materials such as Ag NPs, Cu NPs, CNTs, and natural products is the most applied and effective technique to remove bioaerosols [1].

Various nanomaterials have also been studied for the treatment of drinking water and industrial wastewater, including adsorbents (nZVI or Fe, MnO, ZnO, MgO, Al2O3, TiO2, Magnetite or Fe3O4, CNT), photocatalysts (ZnO, TiO2, metal-based nanocomposites such as Ag/ZnO and Pt/ZnO, CdS, ZnS: Cu, CdS: Eu, CdS: Mn), electrocatalysts (Pt, Pd, Au/metal oxides TiO2, MgO, Fe2O3, Al2O3), nano-membranes (MWCNTs, electrospun PVDF, PVC, sodium titanate nanobelt membrane), disinfectants with antibacterial effects (Ag NPs, chitosan NPs, TiO2), nanosensors (Au NPs, Ag NPs) [14, 16, 18].

#### **2.3 Hybrid nanomaterials**

The term hybrid refers to fusion, joining, or mixing of characteristics at the molecular level, which generates a hybrid material owning the effective functionality of single components and eliminates undesirable characteristics [19, 20]. In this context, hybrid nanomaterials are defined as materials that are made up of two or more organic or inorganic components such as organic-organic (starch-cellulose), inorganic-inorganic (TiO2-Ag), and organic-inorganic (starch-TiO2) compounds, connected at the nanometer scale, combine the intrinsic characteristics of its individual constituents to additional properties due to synergistic effects between the components [21, 22]. These hybrid materials are synthesized by different methods such as covalent immobilization, electrostatic binding, polymerization methods, among others [21]. The properties of the hybrid material vary with the material (organic or inorganic), structure, and different component interface, and the optimum combination can enhance mechanical strength and thermosensitivity, improve thermal and chemical stability, and regulate optical, anticorrosive, magnetic, electrical, and thermal properties as well as fire retardancy [23]. Because of their excellent mechanical, physical, and tribological characteristics, hybrid nanomaterials are widely used in the area of food packaging, plant protection, electrochemistry, and various additional applications in the environmental, biotechnological, and agri-food sectors [19].

Generally, hybrid materials are classified into two categories depending on the intra- and intermolecular interactions among the organic matrix and cross-linking agent [21, 23];


"Polymer-based composites" or "nanocomposites" can be defined as hybrid organic-inorganic composites when incorporating either component in nanoscale and generally obtained by incorporation of a small quantity of an inorganic component into an organic or a polymer matrix in order to form a new component with enhanced properties [24]. The "bio-nano composites" are the materials that comprise particles with at least one dimension in the range of 1–100 nm and a constituent(s) of the biological origin or maybe biopolymers.

Biopolymers (natural polymers) have received much attention in recent last decades due to their abundance, low toxicity, low cost, biodegradability, biocompatibility, and multiple functionalities [25]. A variety of biopolymers such as polysaccharides (cellulose, chitin, chitosan, pectin, starch, dextran, xanthan, guar gum, fucoidan, heparin, hyaluronan, and pullulan), proteins (albumin, casein, collagen, fibrinogen, and gelatin), polylactic acid (PLA), and nucleic acids have been used as alternative eco-friendly materials to replace synthetic polymers or petroleum-based polymers (PP, PE, and epoxies) partially or even totally [25–27]. Polysaccharidebased hybrid nanocomposites have become increasingly essential materials over the past decades [25, 27]. Many studies have reported the application of polysaccharidebased nanocomposites (natural polymer) in various fields such as food, biomedical, ecofriendly and sustainable food packaging, and environmental pollution control and remediation [28–30].

#### *Starch-Based Hybrid Nanomaterials for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.101697*

Due to the poor barrier, mechanical, and processing properties, natural polymers (biopolymers) are incorporated with other synthetic polymers or nanomaterials to improve their properties and applications [31]. Polysaccharides such as cellulose, chitin, chitosan, and starch are the most studied biopolymers and used in biodegradable nanocomposites with metal nanoparticles (Au, Ag, Cu, and Pd), metal oxide nanoparticles (TiO2, ZnO, CuO, Cu2O, SiO2, Fe2O3, and Fe3O4) and carbon nanomaterials (graphene and carbon nanotubes, CNTs) [25].

#### **3. Starch hybrid nanomaterials for environmental remediation**

#### **3.1 Starch**

Starch, a natural, abundant, renewable, biocompatible, and biodegradable biopolymer, is naturally found in many plants as the primary source of energy and reserved in many parts of plants such as stalks, stems, roots, tubers, and seeds; main sources being cassava, wheat, rice, barley, maize or corn, banana, and potatoes, among others. Starch is a heteropolysaccharide that comprises d-glucose monomers joined with glycosidic bonds and can be denoted as (C6H10O5)n with the basic chemical formula. Starch is a heteropolysaccharide composed of two types of macromolecules: linear amylase (around 10–30% of starch granule) and branched amylopectin (remaining 70–90% of starch granule). Amylose is a linear polysaccharide chain of d-glucose units linked by α-(1,4)-glycosidic bond with a degree of polymerization in a range of 300–10,000. Amylopectin is a very high-molecular-weight polymer with a backbone structure of amylase cross-linked through α-(1,6) glycosidic bonds. The basic structure of amylose and amylopectin are shown in **Figure 1** [25, 32, 33].

#### **3.2 Starch hybrid nanomaterials**

Starch-based nanocomposites have wide applications in the fields of food and agriculture, packaging, biomedical, and environmental remediation as emulsion stabilizers, fat replacers, flexible films, carriers of bioactive compounds, drug delivery, and adsorbents in sewage treatment or wastewater treatment [34–36]. Starch nanoparticles are usually smaller than 300 nm in dimension with a high specific surface area. The various forms of starch-based nanoparticles are starch nanoparticles, starch nanospheres, starch micelles, starch vesicles, starch nanogels, and starch nanofibers [36].

Starch is a natural polymer, gained much attention because of its renewability, biodegradability, abundance, eco-friendly, relatively low cost, non-toxic, high adsorptive capacities, amenable to various chemical modifications, and cohesive film-forming properties. Starch molecules can bind with the heavy metal ions or contaminants through the functional (hydroxyl) groups on the starch structure [37, 38]. Further, high amylopectin content in starch has powerful swelling properties that are important in sorption-based applications [39]. In most published works, carbohydrates have been used as reducing, stabilizing, and/or complexing agents [40].

However, starch in a pure or native form has drawbacks such as poor processability, high brittleness, susceptibility to retrogradation, high viscosity, low adsorption capacity, and greater hydrophilicity or high-water absorption capacity, which limits its many applications in the environmental field. To overcome this problem and to obtain water-insoluble materials, starch is modified by physically [hydrothermal

**Figure 1.**

*Structures of starch: (a) amylose and (b) amylose pectin.*

processing (i.e. gelatinization)] or chemically (etherification, esterification, crosslinking, grafting, oxidation, and enzymatic hydrolysis) or a combination of these two methods [41–44]. Polysaccharides exhibit a great number of reactive hydroxyl groups, which can be exploited for direct esterification, etherification, and various chemical modifications [41].

Starch-based hybrid materials have numerous functionalities and/or novel properties due to the interactions between the individual constituents, mostly associated with synergetic effects, and have been reported in environmental remediation applications [25]. Several starch-based composites have been reported to have a remarkable adsorption tendency for the removal of heavy metals and dyes [45].

#### **3.3 Starch-based hybrid nanomaterials in environmental remediation**

#### *3.3.1 Starch/metal or metal oxides or non-valent metals*

**Table 1** shows the recent examples of the combination of starch and different metal, metal oxide, zero-valent metal, CNTs, and other polymers nanoparticles, such as Au, Ag, Cu, Pd, ZnO, TiO2, nZVI, among others. Nanomaterials are widely used to treat different contamination because of their high specific surface area to volume ratio, rapid kinetics, and high reactivity. However, pure or unmodified nanoparticles tend to agglomerate easily into larger particles that decrease the available specific surface area and reactivity. To improve the colloidal stability of nanoparticles, surface modification has been done by coating with various polymers. Of which starch is one of the relatively cheap and green polysaccharides [53, 59].

*Starch-Based Hybrid Nanomaterials for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.101697*


#### **Table 1.**

*Various starch-based hybrid nanomaterials and their applications in environmental remediation.*

Rashid et al. reported that modified tapioca starch could be used as an effective surface modifier for nZVI particles for aqueous nitrate removal [53]. Starch-stabilized Fe/Cu nanoparticles in arsenic (As2+ and As5+) removal from the contaminated water where Cu as a metal catalyst was incorporated with Fe0 (nZVI) to form an iron bimetallic nanoparticle; then, the surface was modified to prevent the agglomeration [46].

Well stabilized (dispersed) iron oxides nanoparticles offer greater specific surface area and sorption capacity than the nanoparticles without any stabilizer towards a wide range of pollutants. Starch-functionalized magnetite (Fe3O4) nanoparticles showed much higher As2+ and As5+ sorption capacity than pristine magnetite nanoparticles [59]. Starch-stabilized Fe3O4 nanoparticles can be used as a "green" adsorbent for the effective removal of perfluorooctanoic acid (PFOA) in soil and groundwater [47]. Baysal et al. reported that starch-coated TiO2 NPs can be successfully used as adsorbents for the removal and determination of heavy metals such as Cd, Co, Cu, Pb, and Ni [11]. The starch-based SnO2 nanocomposite material can be used as an adsorbent for the removal of highly toxic Hg2+ metal ions from an aqueous medium [51].

#### *3.3.2 Starch/carbon nanotubes (CNTs)*

CNTs have gained increased attention in multidisciplinary studies because of their unique physical and chemical properties. However, the hydrophobicity of CNTs may limit their application. The hydrophilicity and biocompatibility of CNTs can be improved by incorporating biopolymers such as starch in the composite system. Incorporating CNTs with starch also helps to overcome the limitation of starch, i.e. weak mechanical properties and poor long-term stability [60, 61]. MWCNTstarch-iron oxide has been reported as a better adsorbent for removing anionic dye methyl orange (MO) and cationic dye methylene blue (MB) from aqueous solutions than MWCNT-iron oxide. The hydrophilic property of soluble starch improved the hydrophilicity of MWCNTs and the dispersion of MWCNT-starch-iron oxide in the aqueous solution. In addition, the increased contact surface between magnetic MWCNT and dyes reduced the aggregates of MWCNTs and facilitated the diffusion of dye molecules to the surface of MWCNTs. Nanoparticles, ZnO, TiO2, or Ag or their complex decompose the adsorbed organic contaminants on MWCNTs as the photocatalysts [60].

#### *3.3.3 Blending starch nanoparticles with different biopolymeric matrices*

Starch-based hydrogels have a good adsorption capacity, which can be used for wastewater treatment by removing various cationic or anionic dyes after modification with functional groups [44]. The incorporation of starch into synthetic polymer hydrogel networks improves their swelling and adsorption capacity [44]. Hydrogel as an adsorbent is one of the best candidates for removing soluble dyes from an aqueous solution. The study of methylene blue (MB) adsorption efficiency of NaOH-treated starch/ acrylic acid hydrogel showed high dye-capturing coefficients, which increase with the starch ratio and indicates the possibility of the hydrogels' application for removing dyes from aqueous solution. In which, starch can be a natural-polymer superabsorbent because of a large number of hydrophilic groups (–OH) and other benefits such as renewable, very cheap, and biodegradable [62]. Biodegradable polymers, starch/cellulose nanowhiskers hydrogel composite, showed outstanding adsorption capacity to be employed in the remediation of methylene blue contaminated wastewaters [63]. Pectin-starch magnetite hybrid nanoparticles could be potential adsorbents for methylene blue dye with higher adsorption efficiency at a low polymer concentration and starch-pectin ratio and can be used to recycle water from the textile industry [58].

#### **3.4 Limitations and future studies for using starch hybrid nanomaterials in environmental remediation**

Increased nano-waste release in the environment, bioaccumulation, occupational exposure, and nanotoxicity are the major problems associated with the increased use of nanomaterials in environmental remediation. Nanoparticles incorporated in starch-based hybrid nanomaterials such as Ag, Au, nZVI, TiO2, SiO2, ZnO, Al2O3, CNTs, metal chalcogenides (CdS, CdSe), polymeric nanoparticles, among others, shows toxicity (acute or chronic) in high dose; growth inhibition of microalgae, disruption of membrane integrity, reactive oxygen species generation, oxidative stress, genotoxicity, and mutagenicity up to reproduction impairment in aquatic species and many health complications in human [41, 64–67].

Because of the very small size, nanoparticles are capable of entering the human body by inhalation, ingestion via food, drink, and drugs, skin penetration, or injections and they have the potential to interact with intracellular structures and macromolecules for long periods [68]. Exposure to nanoparticles is associated with a range of acute and chronic effects ranging from inflammation, exacerbation of asthma, and metal fume fever to fibrosis, chronic inflammatory lung diseases, and carcinogenesis [64].

The effect of surface modification of nanoparticles such as nZVI is not clear. Sun et al. reported that surface modifiers enhance the stability of the nZVI that either increase the toxicity due to prolonged exposure to the living organisms or decrease the toxicity via reducing the adhesion of nZVI to living organisms or preventing the release of toxic ions. Starch stabilized nZVI produced higher phytotoxicity compared to bare nZVI, this may be due to the higher dispersity, hydrophilicity, and anti-aggregation of starch/nZVI that enhances their affinity to root surfaces and the oxidability of the Fe0 , forming a coating of insoluble Fe3+ compounds on the root surface, and thus interferes the absorption of water and nutrients [69].

In the future, attention will be given to the green synthesis of nanomaterials because not all nanomaterials are produced in an eco-friendly way, as involves acid hydrolysis in multiple steps. There are several systems and methods for the green synthesis of nanoparticles, particularly enzymes, vitamins, microwave, bio-based methods, and from plants and phytochemicals [67, 70]. Green synthesis of nanoparticles using various natural sources, non-toxic solvents, and techniques (ultrasound, microwave, hydrothermal, magnetic, and bioproduction by fungi and other microorganisms) promote eco-friendly, sustainable, less expensive, and free of chemical contaminant production and applications [68].

Nano-wastes should be diluted and neutralized before disposal as they are extraordinarily toxic, hazardous, and/or chemically reactive. Proactive nano-waste management strategies need to be adopted to prevent long-term unintended consequences, and, where possible, nano-waste should be recycled [64].

#### **4. Conclusion**

Remediation is the science of removal or reduction of pollutants from the environment using chemical or biological means. Starch-based hybrid materials are a costeffective and eco-friendly solution over petroleum-based polymers in environmental remediation. Though starch is a natural polymer with many benefits, including

renewability, biodegradability, abundance, eco-friendly, relatively low cost, nontoxic, poor barrier, and mechanical properties, poor processability, high brittleness, and high hydrophilicity are major drawbacks of raw starch. Therefore, starch is modified by physical and/or chemical methods, including gelatinization, etherification, esterification, crosslinking, grafting, oxidation, and enzymatic hydrolysis.

Starch-based hybrid materials have numerous functionalities and/or novel properties, mainly associated with synergetic effects and reported in environmental remediation applications. Starches are incorporated with metal NPs, metal oxide NPs, zero-valet metals, CNTs, and other polymers as reducing, stabilizing, and/or complexing agents to remove various toxic contaminants such as heavy metal, organic contaminants, and dye wastewater and groundwater.

In future studies, various natural starch sources, green synthesis of nanomaterials, recyclability, and toxicity effect of nano-waste should be considered. Further development of biodegradable starch-based hybrids and nanomaterials focusing on new functional materials, processing technology, and cost reduction needs to be studied for commercial application.

#### **Conflict of interest**

The authors declare no conflict of interest.

#### **Author details**

Ashoka Gamage1 \*, Thiviya Punniamoorthy2 and Terrence Madhujith3

1 Faculty of Engineering, Department of Chemical and Process Engineering, University of Peradeniya, Sri Lanka

2 Postgraduate Institute of Agriculture, University of Peradeniya, Sri Lanka

3 Faculty of Agriculture, Department of Food Science and Technology, University of Peradeniya, Sri Lanka

\*Address all correspondence to: ashogamage@gmail.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Starch-Based Hybrid Nanomaterials for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.101697*

#### **References**

[1] Ibrahim RK, Hayyan M, AlSaadi MA, Hayyan A, Ibrahim S. Environmental application of nanotechnology: Air, soil, and water. Environmental Science and Pollution Research. 2016;**23**:13754-13788. DOI: 10.1007/s11356-016-6457-z

[2] Mózner Z, Tabi A, Csutora M. Modifying the yield factor based on more efficient use of fertilizer—The environmental impacts of intensive and extensive agricultural practices. Ecological Indicators. 2012;**16**:58-66. DOI: 10.1016/j.ecolind.2011.06.034

[3] Guerra FD, Attia MF, Whitehead DC, Alexis F. Nanotechnology for environmental remediation: Materials and applications. Molecules. 2018;**23**: 1760. DOI: 10.3390/molecules23071760

[4] Singh PP, Ambika. 10— Environmental remediation by nanoadsorbents-based polymer nanocomposite. In: Hussain CM, Mishra AK, editors. New Polym. Nanocomposites Environ. Remediat. USA: Elsevier; 2018. pp. 223-241. DOI: 10.1016/B978-0-12-811033-1.00010-X

[5] Khalid S, Shahid M, Niazi NK, Murtaza B, Bibi I, Dumat C. A comparison of technologies for remediation of heavy metal contaminated soils. Journal of Geochemical Exploration. 2017;**182**:247- 268. DOI: 10.1016/j.gexplo.2016.11.021

[6] Sharma G, Sharma S, Kumar A, Al-Muhtaseb AH, Naushad M, Ghfar AA, et al. Guar gum and its composites as potential materials for diverse applications: A review. Carbohydrate Polymers. 2018;**199**:534-545. DOI: 10.1016/j.carbpol.2018.07.053

[7] Adekeye DK, Popoola OK, Asaolu SS. Adsorption and conventional

technologies for environmental remediation and decontamination of heavy metals: An overview. International Journal of Research and Review. 2019;**6**:505-516

[8] Bushra R. 11—Nanoadsorbents-based polymer nanocomposite for environmental remediation. In: Hussain CM, Mishra AK, editors. New Polym. Nanocomposites Environ. Remediat. USA: Elsevier; 2018. pp. 243-260. DOI: 10.1016/B978-0-12- 811033-1.00011-1

[9] Kaur J, Pathak T, Singh A, Kumar K. Application of nanotechnology in the environment biotechnology. In: Kumar R, Sharma AK, Ahluwalia SS, editors. Adv. Environ. Biotechnol. Singapore: Springer; 2017. pp. 155-165. DOI: 10.1007/978-981-10-4041-2\_9

[10] Singh V, Yadav P, Mishra V. Recent advances on classification, properties, synthesis, and characterization of nanomaterials. In: Green Synth. Nanomater. Bioenergy Appl. Wiley-Black-Well, Hoboken, New Jersey, USA: John Wiley & Sons, Ltd; 2020. pp. 83-97. DOI: 10.1002/9781119576785.ch3

[11] Baysal A, Kuznek C, Ozcan M. Starch coated titanium dioxide nanoparticles as a challenging sorbent to separate and preconcentrate some heavy metals using graphite furnace atomic absorption spectrometry. International Journal of Environmental Analytical Chemistry. 2018;**98**:45-55. DOI: 10.1080/ 03067319.2018.1427741

[12] Bakshi M, Abhilash PC. Chapter 17— Nanotechnology for soil remediation: Revitalizing the tarnished resource. In: Singh P, Borthakur A, Mishra PK, Tiwary D, editors. Nano-Mater. Photocatal. Degrad. Environ. Pollut.

USA: Elsevier; 2020. pp. 345-370. DOI: 10.1016/B978-0-12-818598-8. 00017-1

[13] Das S, Sen B, Debnath N. Recent trends in nanomaterials applications in environmental monitoring and remediation. Environmental Science and Pollution Research. 2015;**22**:18333-18344. DOI: 10.1007/s11356-015-5491-6

[14] Zhang Y, Wu B, Xu H, Liu H, Wang M, He Y, et al. Nanomaterialsenabled water and wastewater treatment. NanoImpact. 2016;**3-4**:22-39. DOI: 10.1016/j.impact.2016.09.004

[15] Durgalakshmi D, Rajendran S, Naushad M. Current role of nanomaterials in environmental remediation. In: Mu N, Rajendran S, Gracia F, editors. Adv. Nanostructured Mater. Environ. Remediat. Cham: Springer International Publishing; 2019. pp. 1-20. DOI: 10.1007/978-3-030- 04477-0\_1

[16] Khin MM, Nair AS, Babu VJ, Murugan R, Ramakrishna S. A review on nanomaterials for environmental remediation. Energy & Environmental Science. 2012;**5**:8075-8109. DOI: 10.1039/ C2EE21818F

[17] Rawtani D, Khatri N, Tyagi S, Pandey G. Nanotechnology-based recent approaches for sensing and remediation of pesticides. Journal of Environmental Management. 2018;**206**:749-762. DOI: 10.1016/j.jenvman.2017.11.037

[18] Anjum M, Miandad R, Waqas M, Gehany F, Barakat MA. Remediation of wastewater using various nano-materials. Arabian Journal of Chemistry. 2019;**12**:4897-4919. DOI: 10.1016/j. arabjc.2016.10.004

[19] Abd-Elsalam KA. Chapter 1— Multifunctional hybrid nanomaterials for sustainable agri-food and ecosystems: A note from the editor. In: Abd-Elsalam KA, editor. Multifunct. Hybrid Nanomater. Sustain. Agri-Food Ecosyst. USA: Elsevier; 2020. pp. 1-19. DOI: 10.1016/B978-0-12-821354-4. 00001-7

[20] Chauhan BPS. Hybrid Nanomaterials: Synthesis, Characterization, and Applications. Hoboken, New Jersey, USA: John Wiley & Sons; 2011

[21] Anaya-Esparza LM, Villagrán-de la Mora Z, Ruvalcaba-Gómez JM, Romero-Toledo R, Sandoval-Contreras T, Aguilera-Aguirre S, et al. Use of titanium dioxide (TiO2) nanoparticles as reinforcement agent of polysaccharide-based materials. Processes. 2020;**8**:1395. DOI: 10.3390/ pr8111395

[22] Meroni D, Ardizzone S. Preparation and application of hybrid nanomaterials. Nanomaterials. 2018;**8**:891. DOI: 10.3390/nano8110891

[23] Rejab MRBM, Hamdan MHBM, Quanjin M, Siregar JP, Bachtiar D, Muchlis Y. Historical development of hybrid materials. In: Hashmi S, Choudhury IA, editors. Encycl. Renew. Sustain. Mater. Oxford: Elsevier; 2020. pp. 445-455. DOI: 10.1016/ B978-0-12-803581-8.10546-6

[24] Nguyen T-P, Yang S-H. 19—Hybrid materials based on polymer nanocomposites for environmental applications. In: Jawaid M, Khan MM, editors. Polym.-Based Nanocomposites Energy Environ. Appl. Woodhead Publishing; 2018. pp. 507-551. DOI: 10.1016/B978-0-08-102262-7.00019-2

[25] Vilela C, Pinto RJB, Pinto S, Marques P, Silvestre A, CSdRF B. Polysaccharide Based Hybrid Materials: *Starch-Based Hybrid Nanomaterials for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.101697*

Metals and Metal Oxides, Graphene and Carbon Nanotubes. Switzerland: Springer Nature; 2018

[26] Russo T, Fucile P, Giacometti R, Sannino F. Sustainable removal of contaminants by biopolymers: A novel approach for wastewater treatment. Current State and Future Perspectives. Processes. 2021;**9**:719. DOI: 10.3390/ pr9040719

[27] Zheng Y, Monty J, Linhardt RJ. Polysaccharide-based nanocomposites and their applications. Carbohydrate Research. 2015;**405**:23-32. DOI: 10.1016/j. carres.2014.07.016

[28] Arora B, Bhatia R, Attri P. 28— Bionanocomposites: Green materials for a sustainable future. In: Hussain CM, Mishra AK, editors. New Polym. Nanocomposites Environ. Remediat. USA: Elsevier; 2018. pp. 699-712. DOI: 10.1016/B978-0-12-811033-1.00027-5

[29] Bilal M, Gul I, Basharat A, Qamar SA. Polysaccharides-based bio-nanostructures and their potential food applications. International Journal of Biological Macromolecules. 2021;**176**:540-557. DOI: 10.1016/j. ijbiomac.2021.02.107

[30] Wen Y, Oh JK. Recent strategies to develop polysaccharide-based nanomaterials for biomedical applications. Macromolecular Rapid Communications. 2014;**35**:1819-1832. DOI: 10.1002/marc.201400406

[31] Kotharangannagari VK, Krishnan K. Biodegradable hybrid nanocomposites of starch/lysine and ZnO nanoparticles with shape memory properties. Materials and Design. 2016;**109**:590-595. DOI: 10.1016/j.matdes.2016.07.046

[32] Nasrollahzadeh M, Sajjadi M, Iravani S, Varma RS. Starch, cellulose, pectin, gum, alginate, chitin and chitosan derived (nano)materials for sustainable water treatment: A review. Carbohydrate Polymers. 2021;**251**: 116986. DOI: 10.1016/j.carbpol.2020. 116986

[33] Robyt JF. Starch: Structure, properties, chemistry, and enzymology. In: Fraser-Reid BO, Tatsuta K, Thiem J, editors. Glycosci. Chem. Chem. Biol. Berlin, Heidelberg: Springer; 2008. pp. 1437-1472. DOI: 10.1007/978-3-540- 30429-6\_35

[34] Campelo PH, Sant'Ana AS, Pedrosa Silva Clerici MT. Starch nanoparticles: Production methods, structure, and properties for food applications. Current Opinion in Food Science. 2020;**33**:136- 140. DOI: 10.1016/j.cofs.2020.04.007

[35] Kim H-Y, Park SS, Lim S-T. Preparation, characterization and utilization of starch nanoparticles. Colloids and Surfaces. B, Biointerfaces. 2015;**126**:607-620. DOI: 10.1016/j. colsurfb.2014.11.011

[36] Yu M, Ji N, Wang Y, Dai L, Xiong L, Sun Q. Starch-based nanoparticles: Stimuli responsiveness, toxicity, and interactions with food components. Comprehensive Reviews in Food Science and Food Safety. 2021;**20**:1075-1100. DOI: 10.1111/1541-4337.12677

[37] Ogunsona E, Ojogbo E, Mekonnen T. Advanced material applications of starch and its derivatives. European Polymer Journal. 2018;**108**:570-581. DOI: 10.1016/j.eurpolymj.2018.09.039

[38] Ragab E, Shaban M, Khalek AA, Mohamed F. Design and characterization of PANI/starch/Fe2O3 bio composite for wastewater remediation. International Journal of Biological Macromolecules. 2021;**181**:301-312. DOI: 10.1016/j. ijbiomac.2021.03.043

[39] Dehabadi L, Wilson LD. Polysaccharide-based materials and their adsorption properties in aqueous solution. Carbohydrate Polymers. 2014;**113**:471-479. DOI: 10.1016/j. carbpol.2014.06.083

[40] Majhi KC, Yadav M. Chapter 5— Synthesis of inorganic nanomaterials using carbohydrates. In: Inamuddin BR, Ahamed MI, Asiri AM, editors. Green Sustain. Process Chem. Environ. Eng. Sci. USA: Elsevier; 2021. pp. 109-135. DOI: 10.1016/ B978-0-12-821887-7.00003-3

[41] Corsi I, Fiorati A, Grassi G, Pedrazzo AR, Caldera F, Trotta F, et al. Chapter 14—Ecosafe nanomaterials for environmental remediation. In: Bonelli B, Freyria FS, Rossetti I, Sethi R, editors. Nanomater. Detect. Remov. Wastewater Pollut. USA: Elsevier; 2020. pp. 383-405. DOI: 10.1016/B978-0-12- 818489-9.00014-1

[42] Khademian E, Salehi E, Sanaeepur H, Galiano F, Figoli A. A systematic review on carbohydrate biopolymers for adsorptive remediation of copper ions from aqueous environments-part A: Classification and modification strategies. Science of the Total Environment. 2020;**738**:139829. DOI: 10.1016/j.scitotenv.2020.139829

[43] Le Corre D, Angellier-Coussy H. Preparation and application of starch nanoparticles for nanocomposites: A review. Reactive and Functional Polymers. 2014;**85**:97-120. DOI: 10.1016/ j.reactfunctpolym.2014.09.020

[44] Pooresmaeil M, Namazi H. Chapter 14—Application of polysaccharide-based hydrogels for water treatments. In: Chen Y, editor. Hydrogels Based Nat. Polym. Elsevier; 2020. pp. 411-455. DOI: 10.1016/B978-0-12-816421-1. 00014-8

[45] Zubair M, Jarrah N, Ihsanullah KA, Manzar MS, Kazeem TS, et al. Starch-NiFe-layered double hydroxide composites: Efficient removal of methyl orange from aqueous phase. Journal of Molecular Liquids. 2018;**249**:254-264. DOI: 10.1016/j.molliq.2017.11.022

[46] Babaee Y, Mulligan CN, Rahaman MS. Stabilization of Fe/Cu nanoparticles by starch and efficiency of arsenic adsorption from aqueous solutions. Environmental Earth Sciences. 2017;**76**:650. DOI: 10.1007/ s12665-017-6992-z

[47] Gong Y, Wang L, Liu J, Tang J, Zhao D. Removal of aqueous perfluorooctanoic acid (PFOA) using starch-stabilized magnetite nanoparticles. Science of the Total Environment. 2016;**562**:191-200. DOI: 10.1016/j.scitotenv.2016.03.100

[48] Okuo J, Emina A, Omorogbe S, Anegbe B. Synthesis, characterization and application of starch stabilized zerovalent iron nanoparticles in the remediation of Pb-acid battery soil. Environmental Nanotechnology, Monitoring and Management. 2018;**9**: 12-17. DOI: 10.1016/j.enmm.2017. 11.004

[49] Mosaferi M, Nemati S, Khataee A, Nasseri S, Hashemi AA. Removal of Arsenic (III, V) from aqueous solution by nanoscale zero-valent iron stabilized with starch and carboxymethyl cellulose. Journal of Environmental Health Science and Engineering. 2014;**12**:74. DOI: 10.1186/2052-336X-12-74

[50] Dong H, He Q, Zeng G, Tang L, Zhang C, Xie Y, et al. Chromate removal by surface-modified nanoscale zerovalent iron: Effect of different surface coatings and water chemistry. Journal of Colloid and Interface Science. 2016;**471**: 7-13. DOI: 10.1016/j.jcis.2016.03.011

*Starch-Based Hybrid Nanomaterials for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.101697*

[51] Naushad M, Ahamad T, Sharma G, Al-Muhtaseb AH, Albadarin AB, Alam MM, et al. Synthesis and characterization of a new starch/SnO2 nanocomposite for efficient adsorption of toxic Hg2+ metal ion. Chemical Engineering Journal. 2016;**300**:306-316. DOI: 10.1016/j.cej.2016.04.084

[52] Chen Y, Zhao W, Wang H, Meng X, Zhang L. A novel polyaminetype starch/glycidyl methacrylate copolymer for adsorption of Pb(II), Cu(II), Cd(II) and Cr(III) ions from aqueous solutions. Royal Society Open Science. 2018;**5**:180281. DOI: 10.1098/ rsos.180281

[53] Rashid US, Simsek S, Kanel SR, Bezbaruah AN. Modified tapioca starch for iron nanoparticle dispersion in aqueous media: Potential uses for environmental remediation. SN Applied Sciences. 2019;**1**:1379. DOI: 10.1007/s42452-019-1364-9

[54] Moradi E, Ebrahimzadeh H, Mehrani Z, Asgharinezhad AA. The efficient removal of methylene blue from water samples using three-dimensional poly (vinyl alcohol)/starch nanofiber membrane as a green nanosorbent. Environmental Science and Pollution Research 2019;**26**:35071-35081. https:// doi.org/10.1007/s11356-019-06400-7.

[55] Xia K, Liu X, Wang W, Yang X, Zhang X. Synthesis of modified starch/ polyvinyl alcohol composite for treating textile wastewater. Polymers. 2020;**12**:289. DOI: 10.3390/ polym12020289

[56] Chowdhury MNK, Ismail AF, Beg MDH, Hegde G, Gohari RJ. Polyvinyl alcohol/polysaccharide hydrogel graft materials for arsenic and heavy metal removal. New Journal of Chemistry. 2015;**39**:5823-5832. DOI: 10.1039/ C5NJ00509D

[57] Sharma G, Naushad M, Kumar A, Rana S, Sharma S, Bhatnagar A, et al. Efficient removal of coomassie brilliant blue R-250 dye using starch/poly(alginic acid-cl-acrylamide) nanohydrogel. Process Safety and Environment Protection. 2017;**109**:301-310. DOI: 10.1016/j.psep.2017.04.011

[58] Nsom MV, Etape EP, Tendo JF, Namond BV, Chongwain PT, Yufanyi MD, et al. A green and facile approach for synthesis of starch-pectin magnetite nanoparticles and application by removal of methylene blue from textile effluent. Journal of Nanomaterials. 2019;**2019**:e4576135. DOI: 10.1155/2019/4576135

[59] Robinson MR, Coustel R, Abdelmoula M, Mallet M. As(V) and As(III) sequestration by starch functionalized magnetite nanoparticles: Influence of the synthesis route onto the trapping efficiency. Science and Technology of Advanced Materials. 2020;**21**:524-539. DOI: 10.1080/ 14686996.2020.1782714

[60] Chang PR, Zheng P, Liu B, Anderson DP, Yu J, Ma X. Characterization of magnetic soluble starch-functionalized carbon nanotubes and its application for the adsorption of the dyes. Journal of Hazardous Materials. 2011;**186**:2144-2150. DOI: 10.1016/j. jhazmat.2010.12.119

[61] Chen Y, Guo Z, Das R, Jiang Q. Starch-based carbon nanotubes and graphene: Preparation, properties and applications. ES Food & Agroforestry. 2020;**2**:13-21. DOI: 10.30919/esfaf1111

[62] Bhuyan MM, Chandra Dafader N, Hara K, Okabe H, Hidaka Y, Rahman MM, et al. Synthesis of potato starch-acrylic-acid hydrogels by gamma radiation and their application in dye adsorption. International Journal of

Polymer Science. 2016;**2016**:e9867859. DOI: 10.1155/2016/9867859

[63] Gomes RF, de Azevedo ACN, Pereira AGB, Muniz EC, Fajardo AR, Rodrigues FHA. Fast dye removal from water by starch-based nanocomposites. Journal of Colloid and Interface Science. 2015;**454**:200-209. DOI: 10.1016/j. jcis.2015.05.026

[64] Gupta R, Xie H. Nanoparticles in daily life: Applications, toxicity and regulations. Journal of Environmental Pathology, Toxicology and Oncology. 2018;**37**(3):209-230. DOI: 10.1615/ JEnvironPatholToxicolOncol. 2018026009

[65] Kasai T, Umeda Y, Ohnishi M, Kondo H, Takeuchi T, Aiso S, et al. Thirteen-week study of toxicity of fiber-like multi-walled carbon nanotubes with whole-body inhalation exposure in rats. Nanotoxicology. 2015;**9**:413-422. DOI: 10.3109/17435390.2014.933903

[66] Ray PC, Yu H, Fu PP. Toxicity and environmental risks of nanomaterials: Challenges and future needs. Journal of Environmental Science and Health, Part C: Environmental Carcinogenesis & Ecotoxicology Reviews. 2009;**27**:1-35. DOI: 10.1080/10590500802708267

[67] Xie F, Pollet E, Halley PJ, Avérous L. Advanced nano-biocomposites based on starch. In: Ramawat KG, Mérillon J-M, editors. Polysacch. Bioactivity Biotechnol. Cham: Springer International Publishing; 2015. pp. 1467-1553. DOI: 10.1007/978-3-319-16298-0\_50

[68] Villaseñor MJ, Ríos Á. Nanomaterials for water cleaning and desalination, energy production, disinfection, agriculture and green chemistry. Environmental Chemistry Letters. 2018;**16**:11-34. DOI: 10.1007/ s10311-017-0656-9

[69] Sun Y, Jing R, Zheng F, Zhang S, Jiao W, Wang F. Evaluating phytotoxicity of bare and starch-stabilized zero-valent iron nanoparticles in mung bean. Chemosphere. 2019;**236**:124336. DOI: 10.1016/j.chemosphere.2019.07.067

[70] Ciambelli P, La Guardia G, Vitale L. Chapter 7—Nanotechnology for green materials and processes. In: Basile A, Centi G, Falco MD, Iaquaniello G, editors. Stud. Surf. Sci. Catal. Vol. 179. USA: Elsevier; 2020. pp. 97-116. DOI: 10.1016/B978-0-444-64337-7.00007-0

### *Edited by Martins Ochubiojo Emeje*

*Starch - Evolution and Recent Advances* is about the historical, scientific, and technological journey of starch so far, taking into account its traditional roles, uses, and applications as well as the most recent advances in the study of this unique polymer. It is a collective endeavor by a group of editors and authors with a wealth of experience and expertise in research and development, teaching, and quality control and public health. Chapters address such topics as the history, evolution, and health benefits of starch, advances in starch and starch product technology, the application of starch and starch-based polymeric materials in nanotechnology and environmental remediation, and much more.

### *Miroslav Blumenberg, Biochemistry Series Editor*

Published in London, UK © 2022 IntechOpen © monsitj / iStock

Starch - Evolution and Recent Advances

IntechOpen Series

Biochemistry, Volume 33

Starch

Evolution and Recent Advances

*Edited by Martins Ochubiojo Emeje*