Abstract:Using silkworm pupa meal and bran as raw materials， silkworm pupa polypeptide was produced by solid-state fermentation of whole cells.The parameters of polypeptide production were optimized to maximize its post-hydrolysis yield.By analysis of orthogonal experiments,the optimal parameters for polypeptide preparation were found to be：hydrolysis temperature of 30 ℃，hydrolysis time of 3 d,and enzyme activity of 2 368 U/g.The polypeptide yield was 21.35 mg/mL，and the hydrolysis rate was 4.58%using the optimized hydrolysis process.Analysis of variance indicated that hydrolysis temperature and time each had significant effects on polypeptide yield and degree of silkworm pupa meal hydrolysis， while enzyme volume had no significant effect. Using Sephadex G-25 gel filtration chromatography to isolate polypeptide， component I and component II were obtained.Both components display·OH scavenging capacity，with scavenging rates of ＞90%.