Modulation of protein-polysaccharide intermolecular interactions: Impact on structure and in vitro digestibility of 3D-structured soy protein matrices.

Abstract

This study investigated the role of protein-polysaccharide intermolecular interactions in governing structural organization and in vitro digestibility of 3D-structured soy protein matrices (SBM). Guar gum (G), sodium alginate (S), and xanthan gum (X) (1-2%, w/w) were incorporated to modulate the intermolecular forces of the systems. Hydrocolloid incorporation significantly enhanced water absorption capacity (WAC), with X exhibiting the strongest effect owing to the formation of a dense and highly viscous network. Hydrocolloid-specific modulation of electrostatic interactions, hydrogen bonding, hydrophobic interactions, and disulfide bonding governed gel network formation, thereby influencing protein accessibility during digestion. Samples containing X showed reduced soluble protein release and lower degrees of hydrolysis, likely due to restricted enzyme diffusion within the compact matrix. In contrast, samples containing G and S promoted protein solubilization through increased matrix hydration and weaker protein-protein interactions. Correlation analysis revealed that WAC was negatively associated with electrostatic and hydrogen bonding interactions, while electrostatic interactions were positively correlated with protein hydrolysis, highlighting the critical role of charge-mediated interactions in regulating digestive behavior. These findings demonstrate that hydrocolloid-induced modulation of intermolecular interactions governs structure-function relationships in soy protein systems, providing mechanistic insights for developing biopolymer matrices with tailored digestibility, with potential applications in plant-based meat analogues and texture-modified foods for dysphagia management.