Impact of different anionic polysaccharides on the stabilization of low-oil emulsions by gelatin-based complexes

The application of gelatin in low-oil emulsions is frequently limited by poor stability. In this study, gelatin-based complexes were respectively constructed with sodium alginate (SA), hyaluronic acid (HA), or Tremella fuciformis polysaccharide (TP), three anionic polysaccharides with distinct molecular architectures. The effects of polysaccharide type and concentration (0.1%, 0.2%, 0.3%, w/v) on the physicochemical characteristics of the complexes and their emulsifying performance were systematically investigated. Non-covalent interactions including electrostatic attraction and hydrogen bonding induced structural unfolding of gelatin, significantly increasing surface hydrophobicity and three-phase contact angle. Notably, the polysaccharide concentration of 0.2% was identified as an optimal balance point. SA exerted the strongest electrostatic contraction, inducing the formation of compact nanospheres. In contrast, HA exhibited steric-dominated aggregation, whereas TP formed branched-structure-mediated spherical assemblies stabilized by a hydrated surface layer and structural reinforcement. Furthermore, emulsions stabilized by gelatin-polysaccharide complexes exhibited more uniform droplet size distributions and markedly enhanced stability. These findings provid a potential strategy for overcoming the instability of low-oil emulsions and may facilitate the development of more stable and healthier instant soup products.