Microwave glycation of soy protein isolate

Download
2019
Namlı, Serap
Soy protein is used as a functional ingredient in the food industry since it has good functional properties like gelling, emulsifying, water and oil holding capacity. It contains all the essential amino acids, lowers the cholesterol, and the risk of cardiovascular disease. Therefore, the improvement of the functional properties of soy protein is an important issue for food science and industry. Glycation is known as the non-enzymatic reaction between the carbonyl group of sugars and the free amino group of proteins. It is known to increase solubility, emulsifying activity, and stability of the proteins. In this study, microwave glycation of soy protein isolate in an aqueous medium with fructose, glucose, and D-allulose (rare sugar) were performed. Protein-sugar ratio (1.6 and 7.2) and the reaction pH (7 and 10) were the other factors examined. As the control, microwave glycation was compared to water bath glycation for soy protein isolate glycated with fructose at pH 10. The concentration of free amino groups was measured by OPA method. Reducing sugar concentration of glycated protein was quantified by HPLC experiments. The formation of the final Maillard products was examined by the UV-VIS at 420 nm and the effects of glycation on solubility were measured by the Lowry method. Structural changes of the soy protein isolate after glycation were investigated by Fourier Transform Infrared spectroscopy (FT-IR) and Time Domain Nuclear Magnetic Resonance (TD-NMR) relaxometry. Alkaline pH was found to be more effective for microwave glycation of soy protein isolate. The reactivity of sugars for microwave glycation reaction was ordered as D-allulose > fructose > glucose. Microwave heating at alkaline conditions caused the isomerization reaction of fructose to D-allulose and glucose, D-allulose to fructose, and glucose to fructose. Microwave heating did not have an effect on increasing the browning degree of the protein upon heating and it was interpreted as microwave glycation did not form the final stage Maillard products. Moreover, microwave heating was found to decrease the solubility of protein at pH 10. FT-IR results showed that a higher degree of glycation reaction was provided by microwave heating. T2 relaxation times obtained by TD-NMR provided valuable information about the structural modification of glycated soy protein isolate and the mobility of water in the system before and after glycation. According to results, microwave heating was found to be more effective for glycation of soy protein isolate than water bath heating.

Suggestions

Effect of high hydrostatic pressure on the functional properties of soy protein isolate
Zengin, Kübra; Alpas, Hami; Department of Food Engineering (2022-2-11)
Soy protein is a low-cost additive with high biological value, unique functional properties, and beneficial effects on health, and it is widely used in the food industry as an important ingredient. When the health and functional properties of soy protein are considered altogether, there are several benefits for consuming and using it in foods. High hydrostatic pressure (HHP) is a non-thermal novel processing technology that has been generally used to destroys vegetative cells, microorganisms and enzymes. Ad...
Investigation of physico-chemical properties of soy proteins glycated with d-psicose
Beylikçi, Sermet Can; Öztop, Halil Mecit; Department of Food Engineering (2019)
Proteins are one of the most essential food components that is constantly used by food industry because of their functional properties as well as their nutritional value. Soy protein has become popular among the usable protein resources because of its various functional properties such as foaming, gelling, emulsifying and water holding capacities. However, certain drawbacks of soy protein like limited solubility especially in acidic environment, emerge the need for modification for further use in broader va...
Pea protein properties are altered following glycation by microwave heating
Ertuğrul, Ülkü; Namlı, Serap; Taş, Ozan; Şümnü, Servet Gülüm; Öztop, Halil Mecit (2021-10-01)
Pea protein is often used in protein enriched diets due to its nutritional properties. Modifying its properties has been studied from many perspectives. Glycation, a non-enzymatic glycosylation reaction of proteins, is one of the modification strategies used to alter its properties like solubility and hydration ability. This study aims to investigate the extent and effect of glycation by MW heating with reducing sugars (glucose, fructose and allulose) on pea protein concentrate (PPC) by determining protein ...
Formulation and characterization of starch and soy protein containing low calorie soft candy
İlhan, Esmanur; Öztop, Halil Mecit; Department of Food Engineering (2019)
Type of sugar and gelling agents used in confectionery formulations have vital importance since they directly influence physicochemical properties during storage. In this study, effect of a non-caloric rare sugar, D-allulose (formerly called D-psicose) on the starch based confectionery gels were investigated in the presence and absence of soy protein isolate using different experimental techniques for 28 days. For characterization of the formulized gel systems, common techniques were used (optical microscop...
Mathematical modeling of swelling in high moisture whey protein gels
Öztop, Halil Mecit (Elsevier BV, 2011-09-01)
Gels prepared from whey proteins can be used for controlled release of nutrients or active ingredients in food systems. The objective of this study was to characterize the water uptake by these hydrophilic gels to aid in the design of release systems. Whey protein isolate (WPI) gels (17% w/w protein) of different aspect ratios were submersed in aqueous solution at pH 7.0. Modeling of mass uptake is presented in terms of Case I (Fickian diffusion) and Case II (kinetic) models. Due to the extent of swelling, ...
Citation Formats
S. Namlı, “Microwave glycation of soy protein isolate,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Food Engineering., Middle East Technical University, 2019.