Comparison of collagen characteristic from the skin and swim bladder of Gulf corvina (Cynoscion othonopterus)

Abstract

Collagens extracted from different tissues and fish species display different physicochemical properties, thus novel sources require characterization. Gulf corvina (Cynoscion othonopterus) is processed industrially for food. Of the by-products, the swim bladder is used for fish maw, but other tissues are treated as waste. In the present study, pepsin-soluble collagen from Gulf corvina skin and swim bladder was extracted and characterized. Skin produced a higher collagen yield (82 ± 1.53 %) than swim bladder (69 ± 1.60 %). Both collagens exhibited electrophoresis bands corresponding to ([α1(I)]2α2(I)) and β chains, all characteristic of type I collagen. Spectra analysis showed the collagens to maintain their triple-helix structure. The skin collagen had a lower denaturation temperature (29.8 °C) than the swim bladder collagen (32.5 °C), due to its relatively low imino acid content (168 vs. 190 /1000 residues, respectively). Both collagens were highly soluble in acidic pH ranges; Zeta potential values were 5.5 for the skin collagen and 6.2 for the swim bladder collagen. Gulf corvina skin and swim bladder are excellent sources of type I collagen with similar physicochemical properties.

Keywords: Collagen characterization; Gulf corvina; Skin; Swim bladder.