Enhanced gelling properties in fish gelatin by refined and semi-refined κ-carrageenan

This study investigated the effects of semi-refined κ-carrageenan (SC) and refined κ-carrageenan (RC) on the gelling properties of fish gelatin (FG) and revealed the critical role of sulfate content in the modification process of FG. RC, with higher sulfate content (23.25%), enhanced FG more effectively than SC. A data model linked sulfate content to FG's gelling properties, showing a significant correlation. Structural analysis revealed that SC/RC formed aggregates with FG, increasing hydrogen bonds and creating a denser gel network. Crucially, the distinct sulfate content and impurity levels between SC and RC, together with a shift in the dominant stabilization mechanism of RC, resulted in differential structural modifications of FG. Finally, the study proposed a schematic model to clearly illustrate the interaction mechanisms between SC/RC and FG. These findings offer new strategies for enhancing FG and provide a theoretical basis for using SC/RC in FG modification. • Effect of two types of carrageenan on the gel properties of FG and its mechanism. • Data fitting of sulfate content of SC and RC to FG basic gel properties. • RC exhibits superior modification due to its higher sulfate content. • Schematic depicting the modification of FG.