Gelatin Production from Rainbow Trout (Oncorhynchus mykiss) Skins and Evaluation of Its Technological Properties

Gelatin production from fish-processing by-products has gained attention as a sustainable strategy for value-added utilization of aquatic resources. In this study, gelatin was extracted from rainbow trout (Oncorhynchus mykiss) skins and its physicochemical, structural, and functional properties were evaluated in comparison with commercial bovine gelatin. Compared with bovine gelatin (220±3.00 g), trout gelatin displayed a milder gel network characterized by a gel strength of 95.1±5.00 g, a pH of 4.78±0.23, and a water-holding capacity of 13.92±0.73 mL water/g protein, reflecting distinct structural and functional behavior rather than reduced quality. In contrast, the high protein content (95.30±0.41%) indicated considerable compositional purity. Functional analyses revealed distinct interfacial advantages for trout gelatin. Oil-binding capacity was significantly higher (1.17±0.10 mL oil/g protein) than that of bovine gelatin (P