Preparation of rice bran polypeptides by enzymatic hydrolysis

The effects of enzyme types,enzyme dosage,enzymatic hydrolysis temperature,enzymatic hydrolysis time and pH on the yield of rice bran polypeptides were investigated,and the preparation conditions of rice bran polypeptides were optimized by response surface methodology.The relative molecular weight of the hydrolysate of rice bran protein by papain was also analyzed.The results showed that papain was the best enzyme for enzymatic hydrolysis of rice bran protein.The optimal preparation conditions of rice bran polypeptides by papain were obtained as follows:enzyme dosage 1.5%,enzymatic hydrolysis temperature 40.5 ℃,pH 5.6,enzymatic hydrolysis time 3.4 h.Under the optimal conditions,the yield of rice bran polypeptides reached 79.3%,and the relative molecular weight of rice bran polypeptides ranged from 500 to 700.