Non-covalent interactions between Lycium barbarum polysaccharides and goat whey protein isolate: Structural changes, odor mitigation and application in yogurt

Lycium barbarum polysaccharides formed complexes with goat whey protein isolate. • Non-covalent interactions induced conformational and microstructural changes in GWPI. • LBP-GWPI complexes modulated volatile compounds associated with goaty flavor. • LBP-GWPI complexes improved the viscosity and water-holding capacity of goat milk yogurt. This study investigated the non-covalent interactions between Lycium barbarum polysaccharide (LBP) and goat whey protein isolate (GWPI), as well as the structural modifications of LBP-GWPI complexes, their effects on volatile release associated with goaty flavor, and their application performance in yogurt. The results demonstrated that LBP bound to GWPI via hydrogen bonding, electrostatic interactions, and hydrophobic interactions, inducing conformational rearrangement and a more compact microstructure of GWPI. The complexation process disrupted the ordered secondary structure of GWPI without altering its primary structure, with the complexes formed at pH 3 exhibiting stronger intermolecular binding and more compact microstructures. Electronic nose analysis indicated that the complexes modulated the release of volatile compounds associated with goaty flavor, with a greater effect observed at pH 3 than at pH 7. Furthermore, application of the optimized LBP-GWPI complex in goat milk yogurt revealed that it effectively maintained structural stability while significantly improving product quality; the optimal ratio was LBP-GWPI = 1:1, which increased yogurt viscosity by 424% at a shear rate of 0.01 s −1 and water-holding capacity by 18.57% relative to the control group. This study elucidates the structure-function relationships of LBP-GWPI complexes in modulating volatile release, providing a feasible green modification strategy and robust theoretical support for quality enhancement and high-value utilization of goat dairy products. Download: Download high-res image (393KB) Download: Download full-size image