Gelatin from specific freshwater and saltwater fish extracted using six different methods: Component interactions, structural characteristics, and functional properties

Abstract

Dry-salting, wet-salting, trypsin, pepsin, acid, and heat methods were used to extract the gelatin from a few saltwater (snakehead) and freshwater (shark) fish skins, and their structural and functional properties and components were then investigated. The results show that enzyme techniques produce fish skin gelatin with a robust triple-helix organization and a sponge-like mesh structure, exhibiting good water absorption(10.67%), fat binding(10.63%), and emulsification properties(89.37 m2/g). The gelatin fiber length and height of shark gelatin extracted by wet salt method were the highest with 617.77 ± 44.04 nm and 17.30 ± 1.45 nm, respectively. Shark skin gelatin produced via heat methods and blackfish skin produced via trypsin exhibits impressive thermal stability, its Tm value was 77.5 °C and 75.7 °C respectively. heatly extracted snakehead and shark gelatin has a high gel strength with 3.06 ± 0.04 N and 3.14 ± 0.04 N. A more in-depth component analysis demonstrates that blackfish skin and shark skin gelatins contain 14 and 9 different forms of collagen proteins, respectively, according to a more thorough component study. Different varieties of gelatin also have other extracellular matrix elements. Notably, trypsin-derived gelatin from shark and blackfish skin has been shown to include biglycan and member 3 (NESH)-binding protein b. The co-assembly of type II improved the gel strength and thermal stability of the gelatin and type XI collagen. Biglycan and decorin can promote the growth of dense network structures. These findings will significantly contribute to the customized applications of fish gelatin and the mechanistic clarification of synthetic biology.