Improving the Stability of Fish Gelatin Emulsion by Microbial Transglutaminase and Polysaccharides in a Steady State

Abstract

This study investigated the enhancement of fish gelatin (FG) emulsion stability by microbial transglutaminase (MTG) and three polysaccharides including konjac glucomannan (KGM), sodium alginate (SA), and guar gum (GG). Notably, a low-temperature (4°C) incubation strategy was used to promote compact wall formation, while parallel experiments at 50°C and non-crosslinked systems served as controls. The results showed that composite modifications of MTG and polysaccharides significantly improved the stability of FG emulsion in a steady state of 4°C. The synergistic combination of MTG-SA at 4 °C observably improved the storage stability of FG emulsion, achieving a 224-fold extension from 9 hours to 28 days (672 hours) under the room temperature. Correspondingly, MTG-SA co-modification at 4 °C enhanced FG emulsion's ESI by 139.5%, while MTG-GG improved EAI by 34.6% under identical conditions. Regardless of polysaccharide types, MTG-polysaccharides at 4°C made FG emulsion the highest apparent viscosity. Polysaccharides markedly reduced FG emulsion droplet size, meanwhile MTG-polysaccharides at 4°C increased absolute zeta potential values, indicating enhanced electrostatic interaction. Furthermore, MTG-polysaccharide co-modified FG emulsions exhibited superior water-holding capacity and surface hydrophobicity, with visibly uniform droplet distribution. In summary, co-modification of polysaccharides (particularly SA) and MTG at 4 °C could significantly improve the stability of FG emulsion.

Keywords: Fish gelatin emulsion, microbial transglutaminase, polysaccharides, physicochemical properties