**Aspects on Starches Modified by Ionizing Radiation Processing Processing**

**Aspects on Starches Modified by Ionizing Radiation** 

DOI: 10.5772/intechopen.71626

Mirela Brașoveanu and Monica-Roxana Nemțanu Additional information is available at the end of the chapter

Mirela Brașoveanu and Monica-Roxana Nemțanu

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.71626

#### **Abstract**

[15] Boufi S, Bel Haaj S, Magnin A, et al. Ultrasonic assisted production of starch nanoparticles: Structural characterization and mechanism of disintegration. Ultrasonics Sonochemistry.

[16] da Silva NMC, Correia PRC, Druzian JI, et al. PBAT/TPS composite films reinforced with starch nanoparticles produced by ultrasound. International Journal of Polymer Science.

[17] Wei B, Cai C, Xu B, et al. Disruption and molecule degradation of waxy maize starch granules during high pressure homogenization process. Food Chemistry. 2018;**240**:165-173

[18] Chang Y, Yan X, Wang Q, et al. High efficiency and low cost preparation of size controlled starch nanoparticles through ultrasonic treatment and precipitation. Food Chemistry.

[19] Fu ZQ, Wang LJ, Li D, et al. Effects of high-pressure homogenization on the properties of starch-plasticizer dispersions and their films. Carbohydrate Polymers. 2011;**86**:202-207

[20] Bel Haaj S, Magnin A, Pétrier C, et al. Starch nanoparticles formation via high power

[21] Shi AM, Li D, Wang LJ, et al. Preparation of starch-based nanoparticles through highpressure homogenization and miniemulsion cross-linking: Influence of various process parameters on particle size and stability. Carbohydrate Polymers. 2011;**83**:1604-1610 [22] Li X, Qiu C, Ji N, et al. Mechanical, barrier and morphological properties of starch nanocrystals-reinforced pea starch films. Carbohydrate Polymers. 2015;**121**:155-162

[23] Jiang S, Liu C, Wang X, et al. Physicochemical properties of starch nanocomposite films enhanced by self-assembled potato starch nanoparticles. LWT—Food Science and

[24] Pagno CH, Costa TMH, De Menezes EW, et al. Development of active biofilms of quinoa (Chenopodium quinoa W.) starch containing gold nanoparticles and evaluation of anti-

[25] Shi Y, Jiang S, Zhou K, et al. Influence of g-C3N4 nanosheets on thermal stability and mechanical properties of biopolymer electrolyte nanocomposite films: A novel investi-

[26] Wetzel B, Haupert F, Zhang MQ. Epoxy nanocomposites with high mechanical and tribological performance. Composites Science and Technology. 2003;**63**:2055-2067

[27] Dai L, Qiu C, Xiong L, et al. Characterisation of corn starch-based films reinforced with

[28] González Seligra P, Eloy Moura L, Famá L, et al. Influence of incorporation of starch nanoparticles in PBAT/TPS composite films. Polymer International. 2016;**65**:938-945

ultrasonication. Carbohydrate Polymers. 2013;**92**:1625-1632

microbial activity. Food Chemistry. 2015;**173**:755-762

gation. ACS Applied Materials & Interfaces. 2014;**6**:429-437

taro starch nanoparticles. Food Chemistry. 2015;**174**:82-88

2018;**41**:327-336

48 Applications of Modified Starches

2017;**227**:369-375

Technology. 2016;**69**:251-257

2017;1-10

Starch is one of the most studied natural polymers due to its widespread and applications as well as to the global interest regarding renewable, cheap, and easy to process resources. The native form of starch is frequently subjected to different processing methods in order to modify its structure and thus to obtain some functional properties suitable in specific industrial applications. Radiation-based method is a "green tool" for modification of natural polymers, such as starch, cellulose, pectin, and chitosan, alginate, having advantages over conventional methods that involve chemical agents associated with environmental toxicity. Radiation processing of natural polymers involves a simple, ecofriendly, and fast process that has harmless feature and provides advanced materials with unique properties. The chapter intends to be an overview of the major findings in the last decade concerning the starches modified by ionizing radiation processing. Therefore, aspects strongly related to changes in physicochemical, functional, and structural properties of starches from various botanical origins are approached. The main key points of this topic are highlighted by a critical evaluation of the mentioned aspects and future perspectives are suggested.

**Keywords:** starch, modification, gamma radiation, electron beam, processing

#### **1. Introduction**

Starch is one of the most widespread and used natural polymers in different applications such as food, pharmaceutical and cosmetics, paper, and textile industries. Even starch is a renewable, cheap, and easy to process resources, its use as a native form has been restricted by some limitations (high viscosity, low solubility in cold water, paste instability, etc.) in specific applications due to its structure. Therefore, starch is frequently subjected to different processing methods (chemical, physical and enzymatic treatments) in order to modify its structure

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. © 2018 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.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

resulting in functional properties suitable in specific industrial applications. The most used way to obtain modified starch is by chemical methods, which are most of the time complex, expensive, and time consuming.

**Type of starch Type of ionizing** 

Wheat Gamma rays; 0.5–10 kGy,

11%

**radiation/processing parameters**

in air, moisture content

Gamma rays; 3–50 kGy, 13.84 Gy/min, in air, moisture content 13.4%

E-beam 6 MeV; 10–50 kGy, 2 kGy/min,

E-beam 2 MeV; 1–4.4 kGy, relative humidity 70 ± 5%

E-beam/6 MeV, 1–10 kGy, in air

0.4 kGy/h, in air, moisture content 9%

E-beam 6 MeV; 10–50 kGy, 2 kGy/min,

in air

Gamma rays; 1–10 kGy, 0.4 kGy/h, in air, moisture content 12%

Rice Gamma rays; 1–5 kGy,

E-beam 3 MeV; 5–30 kGy Pasting profile

in air

**Investigated properties Techniques of** 

Proximate composition

Light transmittance Syneresis

Freeze thaw stability Total amylose content Water and oil absorption

Structural, spectral and morphological properties Thermal properties Apparent amylose content Water solubility index and

swelling power Pasting behavior

Apparent viscosity Intrinsic viscosity Thermal properties Colorimetric properties Molecular weight and molecular

weight distribution

Pasting properties Thermal properties

Swelling volume

Thermal properties

amylose

Acidity

crystallinity

crystallinity

Carboxyl content Pasting properties Thermal properties Granule morphology and

Spectral characteristics

Apparent viscosity Thermal properties Colorimetric properties Molecular weight and molecular

weight distribution

Molecular weight distribution Microscopic characteristics

Leaching of carbohydrates and

Amylose and carboxyl contents

Molecular weight distribution Granule morphology and

Swelling power and solubility

Swelling and solubility indices

Color

capacities Pasting parameters Spectral characteristics **characterization**

http://dx.doi.org/10.5772/intechopen.71626

Aspects on Starches Modified by Ionizing Radiation Processing

Chemical and visible spectroscopic

EPR, FTIR, XRD, SEM, DSC Chemical methods, viscography and viscometry

Rheology, viscometry, DSC, UV-Vis spectrometry,

Viscography, DSC, HPSEC, SEM

Chemical methods, DSC, GPC, SEM, X-ray diffraction

Chemical methods, viscography, DSC, SEM, X-ray diffraction, FTIR

Rheology, DSC, UV-Vis spectrometry,

GPC

Viscography, chemical and spectroscopic methods

Colorimetric properties UV-Vis spectrometry [7]

GPC

methods, viscography, FTIR **References**

51

[9]

[10]

[4, 5, 11]

[12]

[13]

[14]

[15]

[4, 5]

Progressive methods of starch modification are generally considered the physical techniques (e.g., ionizing and non-ionizing radiation treatments, plasma treatment), which are fast, low cost, and environmentally friendly because they do not use polluting agents, do not allow the penetration of any toxic substances in the treated products, do not generate undesirable residual products, and do not require catalysts and laborious preparation of samples.

In the last decade, there is a great amount of reported studies related to the effects of ionizing radiation (gamma radiation, electron beam) on different type of starches. The studies concerning the impact of gamma radiation or electron beam (e-beam) were performed on starches extracted from various vegetal sources—cereals, tubers, legumes, and stems—as presented in **Table 1**.

The reported data showed that ionizing radiation processing generates free radicals on starch molecules that can alter their size and structure, leading to changes of functional and physicochemical properties of starch as a function of experimental processing parameters (irradiation dose, irradiation dose rate, moisture content of samples, and type of gas atmosphere).



resulting in functional properties suitable in specific industrial applications. The most used way to obtain modified starch is by chemical methods, which are most of the time complex,

Progressive methods of starch modification are generally considered the physical techniques (e.g., ionizing and non-ionizing radiation treatments, plasma treatment), which are fast, low cost, and environmentally friendly because they do not use polluting agents, do not allow the penetration of any toxic substances in the treated products, do not generate undesirable

In the last decade, there is a great amount of reported studies related to the effects of ionizing radiation (gamma radiation, electron beam) on different type of starches. The studies concerning the impact of gamma radiation or electron beam (e-beam) were performed on starches extracted from various vegetal sources—cereals, tubers, legumes, and stems—as presented

The reported data showed that ionizing radiation processing generates free radicals on starch molecules that can alter their size and structure, leading to changes of functional and physicochemical properties of starch as a function of experimental processing parameters (irradiation

> Apparent amylose content Thermal properties Pasting profile

Granule morphology and

crystallinity

crystallinity

Pasting behavior Thermal properties Spectral characteristics Granule morphology and

Apparent viscosity Pasting properties Thermal properties Colorimetric properties Molecular weight and molecular weight distribution Granule morphology Spectral characteristics

Apparent viscosity,

Granule morphology

gyration

Molecular weight and radius of

**Investigated properties Techniques of** 

**characterization**

Chemical methods, DSC, viscometry, X-ray diffraction,

SEM

Viscometry, DSC, FTIR, X-ray diffraction, PLM

Rheology, viscography, DSC, UV-Vis spectrometry, GPC, SEM, FTIR

Viscometry, rheology, MALLS,

SEM

Colorimetric properties UV-Vis spectrometry [7]

**References**

[1]

[2]

[3–6]

[8]

dose, irradiation dose rate, moisture content of samples, and type of gas atmosphere).

residual products, and do not require catalysts and laborious preparation of samples.

expensive, and time consuming.

50 Applications of Modified Starches

**Type of starch Type of ionizing** 

Corn Gamma rays; 1–50 kGy, 1 kGy/h, in air

**radiation/processing parameters**

Gamma rays; 3–50 kGy, 19 Gy/min, in air

E-beam 6 MeV; 10–50 kGy, 2 kGy/min,

E-beam 6 MeV; 1–10 kGy, in air

E-beam 6 MeV; 5–100 kGy, solid and

liquid

in air

in **Table 1**.

*Cereal*


**Type of starch Type of ionizing** 

Bean Gamma rays; 5–25 kGy,

185 Gy/h, in air

*Legume*

**radiation/processing parameters**

Gamma rays; 5–15 kGy,

Gamma rays; 5–20 kGy, 2 kGy/h, in air, moisture

Gamma rays; 10 and 50 kGy, 2 kGy/h, in air, moisture content 10%

content 10%

83 Gy/min

**Investigated properties Techniques of** 

Solubility and swelling

Carboxyl content, pH Retrogradation

Apparent amylose content and amylose leaching Water absorption capacity Pasting parameters Thermal properties In vitro digestability Granule morphology and

power

crystallinity Antioxidant activity

Apparent amylose and carboxyl contents Water and oil absorption

Swelling and solubility

Light transmittance Syneresis

Freeze thaw stability Pasting properties Granule morphology and

Spectral characteristics

Carboxyl content, pH Apparent amylose Swelling power and

Light transmittance Syneresis Pasting properties Granule morphology and

Color

capacities Bulk density

indices

crystallinity

solubility Water absorption capacity

crystallinity

leaching

crystallinity

Carboxyl content

Swelling factor and amylose

Apparent amylose content Pasting properties Thermal properties Granule morphology and

Spectral characteristics In vitro digestibility

**characterization**

http://dx.doi.org/10.5772/intechopen.71626

Aspects on Starches Modified by Ionizing Radiation Processing

Chemical methods, viscography, DSC, SEM, X-ray diffractometry

Chemical methods, viscography, visible spectroscopy, SEM, X-ray diffraction,

Chemical methods, viscography, visible spectroscopy, SEM, X-ray diffractometry

Chemical methods, DSC, viscography, FTIR, SEM, optical microscopy, X-ray diffraction

FTIR

**References**

53

[20]

[21]

[22]

[17]


**Type of starch Type of ionizing** 

52 Applications of Modified Starches

Potato Gamma rays; 5–20 kGy,

content 10%

*Tuber*

Elephant foot yam (*Amorphophallus paeoniifolius*)

**radiation/processing parameters**

2 kGy/h, in air, moisture

Gamma rays; 10 and 50 kGy, 2 kGy/h, in air, moisture content 10%

E-beam 6 MeV; 10–50 kGy, 2 kGy/min,

E-beam 6–7 MeV; 110– 440 kGy, in air, moisture

Tapioca E-beam 3 MeV; 5–30 kGy Pasting profile

Gamma rays; 5–25 kGy, 2 kGy/h, in air

content 12%

in air

**Investigated properties Techniques of** 

Carboxyl content Apparent amylose and amylose leaching Swelling power and

solubility Syneresis Pasting properties Granule morphology and

crystallinity

leaching

crystallinity

Carboxyl content

Swelling factor and amylose

Apparent amylose content Pasting properties Thermal properties Granule morphology and

Spectral characteristics In vitro digestibility

Apparent viscosity Thermal properties Colorimetric properties Molecular weight and molecular weight distribution

Phase structure Structure morphology Dynamic viscosity Amount of carboxylic and carbonyl groups Solubility in cold water

Swelling volume Leaching of carbohydrates

Apparent amylose and carboxyl contents Swelling power and

Water absorption capacity Light transmittance Syneresis Pasting parameters

Morphological characteristics

and amylose

Color, pH

solubility

and crystallinity Spectral characteristics Thermal analysis

**characterization**

Chemical methods, spectroscopy, viscography, SEM, X-ray diffractometry

Chemical methods, DSC, viscography, FTIR, SEM, optical microscopy, X-ray diffraction

Rheology, DSC, UV– Vis spectrometry,

Wide-angle X-ray diffraction, SEM, FTIR, rheology, chemical methods

Viscography, chemical and spectroscopic methods

Chemical and spectroscopic methods, viscography, SEM, FTIR, DSC

GPC

**References**

[16]

[17]

[4, 5]

[18]

[13]

[19]


**2.1. Interaction of radiation with matter**

and leads to an excited atom.

and a new molecule.

the substance occur as presented synthetically in **Figure 1**.

**Figure 1.** Fundamental processes of electrons passing through matter.

Gamma rays transfer energy by the photoelectric effect, Compton effect, and pairs generating, leading to liberation of fast electrons that lose energy by the same effects as accelerated electrons of the electron beams. Later on, the energy is absorbed by matter when electrons pass through it and two distinct primary effects, *ionization* and *excitation* of atoms and molecules of

Aspects on Starches Modified by Ionizing Radiation Processing

http://dx.doi.org/10.5772/intechopen.71626

55

Ionization is the primary process by which a neutral atom or molecule becomes charged, and the resulting product is called *ion*. An ion formed by the loss or capture of an electron contains an unpaired electron, being actually a *free radical*, which is highly reactive chemical specie. The ejected electron may ionize further other atoms and molecules by successive collisions and ionizations. Excitation is another primary effect occurring when a high-energy charged particle passes through atoms imparting energy to atomic electrons without ejecting them

The secondary effects consist in different reactions of primary species (ions, excited molecules, or free radicals) that lead to the final products. These effects could be dissociation of an excited molecule into two radicals or into two different molecules. The free radicals participate further in recombination processes between themselves (radical-radical recombination) leading either to the initial molecule or new molecules. The formed radicals can also suffer a recombination with a new molecule abstracting a hydrogen atom forming a new free radical

**Table 1.** Studies relevant to effects of ionizing radiation on various starches.

The chapter gives an overview of the major findings in the last decade concerning the starches modified by ionizing radiation processing. Therefore, aspects strongly related to changes in physicochemical, functional, and structural properties of starches from various botanical origins are approached. The main key points of this topic are highlighted by a critical evaluation of the mentioned aspects and future perspectives are suggested.

It is to be mentioned herein that in the last decade two other reviews regarding the impact of radiation processing on starch [24, 25] have been published, and the most recent one [25] has summarized only the gamma radiation influence on starches.
