Study on feed additive extraction of fish skin polypeptide by B.subtilis complex enzyme
Using alkali treated fish skin and soaking in hydrochloric acid,the collagen peptide was prepared by complex protease;and the peptide determination,sample determination,single factor test design and response surface test design were performed.The effects of pH,temperature and enzyme addition on the enzymatic digestion of tilapia were investigated,and the response surface method of B.subtilis was optimized.The results showed that the best process parameters for the extraction of fish skin poly peptide feed additive by B.subtilis compound enzyme were:the extraction rate of polypeptide 14.63%,pH 7.64,temperature 50.30 ℃.Under these experimental conditions,the amount of enzyme was 1.55%,and the extraction rate of polypeptide was the highest.The extraction process parameter was good,stable and feasible,which could provide a theoretical basis for the subsequent development and utilization of fish skin polypeptide feed additives.