Abstract:Soybean dregs were used as raw material for hydrolysis by alkaline protease to obtain protein hydrolysate peptides,and the antioxidant activity of the peptides was investigated.With the degree of hydrolysis as the index,the degree of hydrolysis of soybean dregs by alkaline protease was analyzed in terms of hydrolysis pH,hydrolysis temperature,hydrolysis time and enzyme addition.The results showed that the optimal conditions for hydrolysis by alkaline protease were pH 9.25,a hydrolysis time of 3.05 h,an enzymatic activity of 8 108 U/g,and a hydrolysis temperature of 53℃,and the degree of hydrolysis was 91.23%.The order of factors affecting the degree of hydrolysis of soybean dregs was as follows:hydrolysis temperature>hydrolysis time>enzyme addition>pH level.The antioxidant activity of the hydrolysate peptides of soybean dreg protein was determined by DPPH radical scavenging assay.The results showed that the DPPH radical scavenging ability of the hydrolysate peptides was the strongest at a concentration of 6%,and the scavenging rate was 71.32%.