Enzymatic preparation of peanut peptides and analysis of their antioxidant activity

In order to improve the utilization value of peanut meal and develop healthy and safe peanut peptide functional foods, peanut protein was extracted by alkaline extraction and acid precipitation, and peanut antioxidant peptides were prepared by alkaline protease enzyme, and the preparation process was optimized by one-way test, Plackett-Burman test, and response surface test, and the compositions and structures before and after the enzyme digestion were determined, and their antioxidant stability was evaluated by simulating gastrointestinal tract digestion in vitro. The results showed that the optimal conditions for the preparation of peanut antioxidant peptides were pH 9.5, at the temperature of 50 ℃, alkaline protease addition of 6 100 U/g, substrate concentration of 4%, and treatment for 4 h. The ABTS radical scavenging rate of the peanut antioxidant peptides prepared under these conditions was up to 90.31%±0.53%, and the degree of hydrolysis was up to 35.06%±1.29%, with no significant difference with the predicted values. The antioxidant activity of peanut peptide prepared by this process was increased by about 50% compared with that of peanut protein; the peanut peptide still maintained high antioxidant activity after simulated digestion in vitro. The results provide a theoretical basis for the efficient preparation of peanut antioxidant peptides and the promotion of the application of peanut meal in food processing industry.