Rheological Stability, Enzyme Activity, and Incorporation of Pseudocereal Powder as an Alternative Ingredient in Health-Related Food

*Noorazwani Zainol, Harisun Yaakob, Nurul Elia Aqila Abu Rahim, Nor Hasmaliana Abdul Manas, Norsuhada Abdul Karim and Dayang Norulfairuz Abang Zaidel*

## **Abstract**

In response to the growing recognition of health issues, people are seeking products that are inexpensive, convenient, and health-related. The incorporation of pseudocereal powder in nutraceutical sector is currently increasing because of their high nutritional profile as well as health-promoting effects. The high nutritional profile includes low starch content, high in amino acid profile, high in mineral content, and low glycemic index. Moreover, it contains high levels of phytochemicals that contain considerable amounts of flavonoids, polyphenolic chemicals, and phytosterols, making them useful in the nutraceutical sector. These bioactive compounds offer antioxidant, antiinflammatory, and reduced risk of obesity, prediabetes, and diabetic complications. With its tremendous potential and numerous food health-related uses, pseudocereal can serve as a low-cost alternative ingredient in health-related food products. Several pseudocereal processes via enzyme activity, as well as the high rheological stability of its starch, have made pseudocereal an attractive option for modern agriculture.

**Keywords:** rheological stability, enzyme activity, health benefits

### **1. Introduction**

Pseudocereal grains are edible seeds of dicotyledonous species that possess the same physical characteristics as cereal grains, such as having less or similar starch content, contribute high caloric value [1, 2] and an edible appearance [3]. The trend of pseudocereals in human diet is becoming more popular, because they fulfill high nutritional and nutraceutical needs while being gluten-free (GF). Moreover,

gluten-free diet has become increasingly popular in recent years due to the increasing number of individuals having gluten intolerance, celiac disease, and self-awareness toward health. One of the topics that has received a lot of interest and is still being explored is the processing of pseudocereal powder and its application in glutenfree food development with desired texture. Pseudocereal powder manufacture has opened the door for these crops to be used into a wide range of food industries. Besides pseudocereal is an important resource for developing functional foods, research has also highlighted pseudocereal as the potential resource for health benefits [4, 5]. Secondary metabolic analysis of pseudocereals indicated that they contain considerable amounts of flavonoids family, polyphenolic components, and phytosterols, which contribute to the therapeutics properties [6–11]. In addition, they offer great potential for the future because of their high genetic diversity, allowing them to adapt to a wide range of climatic conditions, from tropical to temperate [4, 5, 12].

Pseudocereals have been referred to as twenty-first century grains due to their high nutritional value [13]. They contain high amounts of starch, fiber, and proteins with a balanced essential amino acid composition, among which are many sulfur-rich amino acids. When compared with cereals, the protein quality and quantity in pseudocereals are far superior and have emerged as a significant source of bioactive peptides in the recent decade [14]. Pseudocereal grains are rich in starch, which comprise between 60% and 80% of seed weight, which can be classified as rapidly digestible, slowly digestible, or resistant to digestion [15]. Resistant starch (RS) causes a beneficial effect on the body as it cannot be digested and absorbed in the small intestine, instead passing to the colon where it is fermented by microorganisms into short-chain fatty acids. Current dietary guidelines recommend that at least 14% RS on a total starch basis is required for health advantages. On the other hand, simple starch contains monosaccharides compound such as glucose, fructose, arabinose, xylose and disaccharides compound such as sucrose and maltose, which exist in less quantity in pseudocereal. A significant amount of dietary fiber, lipid, mineral, and vitamin contents existing in pseudocereal enhances the nutritional value of these crops and permits their entry in the functional food sector. In general, dietary fiber of pseudocereal can be divided into two groups: insoluble and soluble polysaccharides. Out of 78% of total dietary fiber content consists of insoluble polysaccharides while 22% consists of soluble polysaccharides where hemicellulose, branched-galacturonan, cellulose [4, 5] and xyloglucans, lignin, cellulose [16] are the examples of insoluble and soluble polysaccharides, respectively. For lipid profile, pseudocereal is reported to possess a high value of polyunsaturated fatty acid, which consists of linolenic acid and linoleic acid [17, 18] whereby unsaturated fatty acid, oleic acid, and palmitic acid are among the abundant fatty acids existing [19, 20]. The mineral compounds of pseudocereal are abundant in coat; therefore, as a whole pseudocereal are a good source of mineral.

### **2. The rheological modification of pseudocereal starches**

The study of starch gelatinization properties through viscometer analysis is very important for understanding the viscosity changes and evaluating the disintegration of starch components and their tendency to regenerate when forming new hydrogen bonds, thereby forming viscoelastic gels [21]. The pasting properties of native pseudocereal starches are summarized in **Table 1**. From **Table 1**, the measurements of pseudocereal starch paste's viscosity are analyzed using Modular Compact Rheometer (unit recorded as cP), Rapid Visco-Analyzer (RVA), Brabender Amylograph (BA),

*Rheological Stability, Enzyme Activity, and Incorporation of Pseudocereal Powder… DOI: http://dx.doi.org/10.5772/intechopen.101890*


#### **Table 1.**

*Pasting properties of native pseudocereal starches.*

or using a dynamic rheometer in a flow temperature ramp mode. In general, data obtained as in **Table 1** show that the pasting temperature affects the ability of starch to imbibe water whereby as the pasting temperature rises, the likelihood of paste creation rises. Hence, it can be suggested that in the presence of water and heat, starch granules swell and form paste by imbibing water [21]. The pasting temperature of pseudocereal starch as in **Table 1** ranges from 63.7 to 95°C, and it can be differentiated into two groups, which is the higher pasting temperature ranging from 81.88–95°C [22, 23] while the lower pasting temperature ranges from 63.7 to 68.75°C [21, 24, 25]. The pasting temperature depends on the size of the starch granules where small granules are more resistant to rupture and loss of molecular order, so this might explain the relatively high pasting temperature [26].

The modifications of pseudocereal starches were studied by many researchers to improve the functional and rheological properties of pseudocereal starch [22–25, 27]. Pasting properties of modified pseudocereal starches in comparison with their respective native pseudocereal starches are summarized in **Table 2**. There are three types of modified pseudocereal, namely physical modification, chemical modification, and physicochemical modification as in **Table 2**. In general, chemical modification of starch resulted in significantly increased peak viscosity compared with the other two types of modified pseudocereal. This is probably due to the increased granular stiffness, which is resultant of starch chain interactions within the amorphous region and an increase in crystalline order [24]. Oxidization, acetylation, and octenylsuccinylated (OSA) as in **Table 2** increased the peak viscosity of *Amaranthus hypochondriacus* that might be accredited to the higher swelling power and comparable solubility of starch relative to native starch. Final viscosity signifies the starch ability to develop viscous paste on cooling after cooking the starch solution.

Physical modifications of pseudocereal starches by heat moisture treatment (HMT) were studied in two types of amaranth spp. such as *A. caudatus* [21] and *A. hypochondriacus* [22] as in **Table 2**. Heat moisture treatment causes intensifying decrement in setback viscosity with rising amylose content in starches as hightemperature treatment supports added interactions between amylose-amylose and


#### *Pseudocereals*

