Effect of Hydrolysis on Structure and Properties of Duck Myofibrillar Protein in Low-salt Condition

To investigate the effects of hydrolysis time (0, 20, 40, 60, 80 min) on the structure and functional properties of duck myofibrillar protein in low-salt solution, the duck myofibrillar protein was hydrolyzed by trypsin, the structure and functional properties of hydrolysate was assessed by analyzing the degree of hydrolysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), solubility, surface hydrophobicity, secondary structure, fluorescence spectrum, Zeta potential and emulsification after hydrolysis treatment. The results showed that in low-salt condition, with the prolongation of hydrolysis time, the solubility increased significantly (P<0.05), the surface hydrophobicity first decreased and then increased, while the emulsification first increased and then decreased. When the hydrolysis time was 40 min, the hydrolysis degree was 4.15%, the solubility and emulsification of duck MP were the highest, reaching 60.57% and 21.2 m²/g respectively, and the surface hydrophobicity was lowest (40.85 BPB/μg). In addition, the protein structure was changed significantly, the α-helix content decreased, the endogenous tryptophan fluorescence intensity was obviously higher than that in the unhydrolyzed group, and the absolute value of Zeta potential increased. In summary, in low-salt condition, hydrolysis for 40 min can effectively improve the structural and functional properties of duck MP.