Optimization of Stepwise Dual-enzymatic Preparation of Peanut Polypeptides

In order to exploit and utilize peanut protein resource and obtain high value-added protein products,defatted peanut protein powder was subjected to stepwise hydrolysis initially with alcalase followed by flavourzyme. The conditions for flavourzyme hydrolysis was optimized by response surface methodology in the present study. The effects of enzyme amount,substrate concentration,hydrolysis temperature,hydrolysis time and pH on soluble nitrogen content in peanut protein hy-drolysate were explored by single-factor method,and a mathematical regression model describing soluble nitrogen content in peanut protein hydrolysate at different levels of four other factors except pH was established. The optimal process parameters for flavourzyme hydrolysis were found to be:pH,7.0; enzyme amount,1714 U/g substrate; hydrolysis temperature,55 ℃; and hydrolysis duration,90 min. Te soluble nitrogen content in the peanut protein hydrolysate obtained under the above conditions was 9.44 mg/mL.