Functional Properties Of The Soy Protein

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Abstract: Functional properties of the soy protein need to improve to have better applications in food industry. Alkali extracted and acid precipitated soy protein isolate (SPI) was glycosylated using D-glucose (G) and Xanthan gum (X) via Maillard reaction to improve solubility. The effects of SPI to G and SPI to X ratios (SPI:G = 2:1, 1:1, and 1:2; SPI:X = 100:1 and 10:1) and incubation time (0, 6, 12, and 24 h) on the solubility and functional properties of glycosylated SPI were evaluated. The SPI:G ratio of 1:2 yielded a maximum degree of glycosylation of 71.1%. The solubility of SPI after glycosylation significantly increased (P<0.05) at pH 4.0-8.0 compared to SPI alone. Although the emulsion stability of glycosylated SPIs was not…show more content…
In the food industry, soybean protein has wide range of applications especially in the processed foods (meat, milk, beverage, and bakery products), due to its nutritional and functional benefits (Liu 1999). The functional properties of proteins such as solubility, gelation, emulsification, foaming, and viscosity are playing a major role in the food systems. It is a common practice to modify those functional properties for effective application to improve food flavor, texture, color, and storage stability (Zhang et al 2007). The improved functionalities of soy protein isolate will expand its usage in food processing since most of commercially available soy protein isolates have undesirable functionalities due to poor solubility (Zhang et al 2007). Chemical and enzymatic methods are commonly used for proteins modifications because of its cost effective procedures. The chemical modifications (glycosylation, acetylation, alkylation, esterification, amidination, and deamination) have been extensively studied for protein functionality improvements (Aminlari et al 2005).
Among the various chemical modifications, glycosylation describes the covalent coupling reactions between the ε- or N-terminal amino group of proteins and the carbonyl group of polysaccharide chains (Aminlari et al 2005). Various proteins such as ovalbumin, soy protein isolate, whey protein isolate, and peanut protein isolate have been evaluated for glycosylation process and shown to
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