Double-spotted pufferfish (Takifugu bimaculatus) skin collagen: Preparation, structure, cytocompatibility, rheological, and functional properties

Abstract

Collagen has been ubiquitously applied in the food, cosmetic, biomedical, and pharmaceutical industries. However, the existing collagen in the market cannot meet the demand of consumers. In this study, double-spotted pufferfish collagen (DPC) was extracted from the skin of the pufferfish and characterized as type I collagen, which maintains a native triple helical structure. Liquid chromatography-tandem mass spectrometry analysis revealed that α1 and α2 subunits of DPC comprised 378 and 372 uninterrupted Gly-X-Y triplets, respectively, which were 78.3 % and 78.4 % of the total amino acid content. Secondary structure analysis revealed that DPC consisted of 50.23 % α-helices, 26.51 % β-sheets, 23.26 % β-turns, and 0 % random coils. Using XRD, the distance between collagen molecular chains was found to be 11.45 Å. The yield of DPC was 49.83 % ± 1.85 % (dry weight basis), which was higher than that of pigskin collagen. Dynamic sweep and steady-state shear of DPC were significantly affected by temperature and concentration. DPC solutions exhibited shear-thinning rheological behavior. DPC exhibited water holding and oil absorption capacities superior to terrestrial collagen, such as that of chicken feet collagen. The foaming properties and emulsifying properties of DPC were superior to commercial collagen, such as that of black ruff collagen. DPC was nontoxic to MC3T3-E1 cells and had good cytocompatibility. These results suggest that DPC is a new alternative for collagen with potential for further applications in food, cosmetic, and biomedical fields.