Optimization of enzyme-assisted extraction and characterization of collagen from Chinese sturgeon (Acipenser sturio Linnaeus) skin

Background: Sturgeon (Acipenser sturio Linnaeus) skin contains high amount of nutrients including unsaturated fatty acids and collagen. A pepsin-assisted extraction procedure was developed and optimized for the extraction of collagen from Chinese sturgeon (Acipenser sturio Linnaeus) skins. Objective: To determine the optimum conditions with the maximum yield of the pepsin-soluble collagen (PSC) extraction. Materials and Methods: The conditions of the extraction were optimized using response surface methodology. The Box-Behnken design was used to evaluate the effects of the three independent variables (extraction time, enzyme concentration, and solid-liquid ratio) on the PSC yield of the sturgeon skin. Results: The optimal conditions were: solid-liquid ratio of 1:11.88, enzyme concentration of 2.42%, and extraction time of 6.45 h. The maximum yield of 86.69% of PSC was obtained under the optimal conditions. This value was not significantly different from the predicted value (87.4%) of the RSM (P < 0.05). Conclusion: The results of this study indicated that the production of PSC from sturgeon skin is feasible and beneficial. The patterns of sodium dodecyl sulfate-polyacrylamide gel electrophoretic patterns (SDS-PAGE) indicated that the sturgeon skin contains type I collagen, which is made of α-chain and β-chain. The infrared spectra of the collagens also indicated that pepsin hydrolysis does not affect the secondary structure of collagen, especially triple-helical structure.