Pectin-driven microphase separation regulates hierarchical network formation and rheological functionality in egg yolk high-density lipoprotein fibril hydrogels.

Protein-polysaccharide interactions play a central role in structuring food hydrogels, yet how anionic polysaccharides induce spatial organization in lipoprotein fibril systems remains unclear. Here, pectin was incorporated into egg yolk high-density lipoprotein (HDL) fibril hydrogels to investigate polysaccharide-driven microphase separation and its effects on network architecture. The anionic backbone of pectin promoted competitive intermolecular interactions, strengthening electrostatic attraction and hydrogen bonding while weakening hydrophobic interactions and disulfide bonding. These shifts triggered microphase separation, resulting in heterogeneous yet interconnected gel networks. Consequently, gels exhibited enhanced stiffness, strain-dependent structural rearrangement, and improved energy dissipation. Water redistribution toward more immobilized states and increased thermal stability further supported the formation of constrained hierarchical structures. Overall, this study identifies microphase separation as a key molecular mechanism governing structure-function relationships in HDL fibril hydrogels and advances the understanding of polysaccharide-mediated network organization in food biopolymer systems.