Structural Properties and Biological Activities of Collagens from Four Main Processing By-Products (Skin, Fin, Cartilage, Notochord) of Sturgeon (Acipenser gueldenstaedti)

During the processing of sturgeon, large amounts of by-products, such as skin, fin, cartilage, and notochord, are produced. These by-products have not been effectively used, resulting in a serious waste of sturgeon resources. In this study, we aimed to obtain the collagen from these by-products and evaluate the fibril-forming characteristics of the collagen molecules and the antioxidant activity of the collagen peptides. The structural properties of pepsin-soluble collagen were analyzed by SDS-PAGE and FTIR. Collagen fibril-forming characteristics were detected by turbidity assay and SEM observation. The antioxidant activities of collagen peptides were determined by Hydroxyl and ABTS radical scavenging assays. SDS-PAGE results showed that the skin and fin collagens were characterized as type I collagen, and the cartilage and notochord collagens were characterized as type II collagen. Sturgeon type II collagens could only be self-assembled into fibrils at low phosphate ion concentration, whereas sturgeon type I collagens could be self-assembled into fibrils at long range of phosphate ion concentrations. The fibril-forming ability of sturgeon type I collagen was higher than that of porcine type I collagen. The fibril diameter of type I collagen was higher than that of type II collagen. The antioxidant activity of notochord and skin collagen peptides was higher than that of the other two collagen peptides. The results of this study will provide helpful information for the application of sturgeon collagen in the functional food and biomedical material industries. Meanwhile, it will promote the effective use of collagen from different sturgeon by-products.