Abstract:The bone of Anser cygnoides was used in the experiment that was hydrolyzed by complex enzyme.For preparing the collagen polypeptide of Anser cygnoides bone，the single factor experiment was carried out for determining the optimal enzymatic hydrolysis process combined with the method of response surface.The degree of hydrolysis which was indicated as an indicator expounded that the best complex enzymes formed of papain，neutral protease and alkaline protease with a mass ratio of 1∶2∶1.The optimal enzymatic conditions included temperature as 50℃，pH as 7.1，enzyme amount as 6 100 U/g，time as 5 h，showed the result of hydrolysis degree was 26.34%.For analysed the free radical scavenging ability of Anser cygnoides bone collagen polypeptide，superoxide anion and hydroxyl radical scavenging experiments were carried out，the result suggested that the antioxidant activity of Anser cygnoides bone collagen polypeptide was positively correlated with the concentration of collagen polypeptide.When the substrate concentration was 6 mg/mL，the scavenging rates of superoxide anion and hydroxyl radical were 59.21% and 51.82%，respectively.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE）experiment and exclusion chromatography showed that the molecular weight of Anser cygnoides bone collagen polypeptide was from 851 Da to 11 092 Da.Amino acid composition analysis showed that the Anser cygnoides bone collagen polypeptide was rich in glycine，alanine，proline，hydroxyproline and aspartic acid and these specific amino acids were related to the antioxidant activity of the collagen polypeptide.