Effects of oxidative modification on thermal aggregation and gel properties of soy protein by peroxyl radicals

Effects of protein oxidation on thermal aggregation and gel properties of soy protein by 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-derived peroxyl radicals were investigated in this article. Incubation of soy protein to increase concentration of AAPH resulted in a decrease in particle size and content of thermal aggregates during thermal-induced denaturation. Protein oxidation resulted in a decrease in water-holding capacity (WHC), gel hardness and gel strength of soy protein gel. An increase in coarseness and interstice of the gel network was accompanied by uneven distribution of interstice as extent of oxidation of soy protein increased. A decrease in disulphide content and formation of oxidation aggregates in the process of oxidative modification were contributed to the decline of particle size and content of thermal aggregates during thermal-induced denaturation, leading to a decrease in WHC, gel hardness and gel strength of soy protein gel.