Study on influence on yield of soy peptides

Microthermal soybean meal were deal with in three different ways(acid water washing,water washing after alcohol washing,extract soy protein isolated)before hydrolyzed by Alcalase alkaline enzyme.The best pretreatment method was defined as water washing after alcohol washing through analysis on the index of the yield,color and the odor of soy peptides.Then,in the single-factors analysis,the influences of substrate concentration,pH,temperature and enzyme concentration on the protein hydrolysis degree(DH)and yield of soy peptides were studied.The response surface analysis were used to optimize the condition of enzyme hydrolysis,the results showed that the optimum condition for preparing high-yield soy peptides were:substrate concentration 5%(w/w),pH8.77,temperature 56.53℃,enzyme concentration 5400U per gram protein.In this condition,hydrolysis degree of soy protein isolate is 22.56%,the yield of soy peptides is 77.90%.