Alkaline-heat-induced protein co-assembly combined with hyaluronic acid surface modification for improving functional properties of pea protein.

This study aimed to improve the functional properties of pea protein using alkaline-heat-induced pea-whey protein co-assembly and hyaluronic acid (HA) surface modification. Alkaline-heat treatment reduced the particle size of pea protein to 300-600 nm and formed loose porous aggregates mainly driven by hydrophobic interactions. HA further bound to the composite proteins through hydrogen bonding to form ternary complexes. The addition of 0.3% HA increased protein solubility from 32.6% to 43.8%, improved emulsifying activity and water-holding capacity, had limited effects on foaming properties, and reduced oil-holding capacity. Structural analyses showed that HA interacts with protein assemblies to shield tryptophan residues, regulate the protein secondary structure, and modulate its thermal stability. In vitro simulated gastrointestinal digestion revealed that HA reduced the gastric digestibility of the composite protein through steric hindrance and viscosity regulation, but exerted limited effects on intestinal digestibility. These findings demonstrate that alkaline-heat assembly combined with HA surface modification is an effective strategy for developing pea-based colloidal ingredients with improved functionality and controlled digestive behavior.