Effects of Transglutaminase and Epigallocatechin Gallate on the Structural and Physicochemical Properties of Fish Skin Gelatin from Takifugu rubripes.

Fish skin gelatin (FG) has garnered considerable attention as a potential substitute for mammalian gelatin. In this study, Takifugu rubripes skin gelatin was chemically modified using transglutaminase (TG) and epigallocatechin gallate (EGCG). Subsequently, the rheological, structural, and physicochemical properties of FG modified with varying concentrations of TG and EGCG were systematically examined and compared. As the concentrations of TG and EGCG increased, more extensive interactions occurred in FG, leading to a significant enhancement of gelatin properties. Following modification, the molecular weight of FG proteins increased, and this was accompanied by enhanced surface hydrophobicity and gel strength. Rheological analysis further demonstrated that the viscosity of FG modified with TG and EGCG was higher than that of unmodified FG and was positively correlated with the treatment concentrations of TG and EGCG. Additionally, the results indicated that the effect of TG modification was more pronounced than that of EGCG modification. Overall, this study demonstrates that both TG and EGCG modifications can effectively overcome the inherent limitations of fish skin gelatin, with TG showing superior efficiency as a cross-linking agent. The enhanced thermal stability, gel strength, and rheological properties achieved through these interactions significantly expand the potential applications of fish gelatin in the food industry, making it a more viable alternative to mammalian gelatin.