Molecular interactions and gel network modulation in ionic polysaccharide-gelatin hydrogels for improved texture of skipjack tuna products

The present study investigates the enhancement of skipjack tuna (Katsuwonus pelamis) texture by incorporating ionic polysaccharide-bovine bone gelatin (BBG) hydrogels. Three ionic polysaccharides, namely carboxymethyl chitosan (CMCS), konjac glucomannan (KGM), and oat β-glucan (OBG), were utilized in BBG-based hydrogels. And their effects on the rheological, structural, and protein properties of the composite gels were explored. Results showed that charge density influenced pore size, wall thickness, and cross-linking density in hydrogels. Structural analyses revealed that all polysaccharides promoted ordered rearrangements in protein secondary structure, increasing surface hydrophobicity and β-sheet content, with OBG having the pronounced effect by mediating gelation through enhanced hydrophobic interactions and hydrogen bonding. The incorporation of BBG + OBG-20 % hydrogels significantly enhanced water-holding capacity, and texture while reducing oral processing energy (p < 0.05). These findings provide insights for improving the texture of skipjack tuna products and demonstrate the potential application of polysaccharide-BBG hydrogels in enhancing the quality of fish products.