Mechanistic insights into lipid-driven structural evolution of cod protein soft gels: From interfacial reconstruction to protein conformational migration.

Abstract

Lipids can modify the texture of protein-based foods, but how the type of lipid added regulates protein conformation and gel-network formation through interfacial reconstruction remains unclear. Therefore, this study compared the effects of incorporating egg white microgel-stabilized high internal phase emulsions (HIPEs) or soybean oil into cod protein soft gels prepared by high-pressure homogenization. The aim was to clarify texture-regulation mechanisms. Both systems, but particularly soybean oil, increased hardness, and promoted disulfide bonding while weakening hydrogen bonds and hydrophobic interactions. Lipid addition enlarged structural units and increased fractal dimensions. HIPEs formed a more complex interfacial structure and elastic interfacial film than soybean oil, as indicated by higher surface fractal. Molecular dynamics simulations revealed cooperative and competitive adsorption among HIPEs components, forming a denser composite interfacial layer (G' > G″). Thus, lipid incorporated determines controls protein conformational migration, network reorganization, and gel texture through distinct interfacial reconstruction pathways.