Characterization of the gel-binding mechanism of Grifola frondosa polysaccharide and polymerized whey protein by simultaneous rheology and Fourier-transform infrared spectroscopy and its application in yogurt

The study aimed to develop and characterize composite hydrogels composed of polymerized whey protein (PWP, 10% wt/vol) and Grifola frondosa polysaccharide (GFP, 0%-4% wt/vol) as a natural functional additive for yogurt. The hydrogel structure change was elucidated at the molecular level using simultaneous rheology and Fourier-transform infrared spectroscopy. Results indicated that GFP significantly enhanced the hydrogel's network density and thermal stability through hydrogen bonding and electrostatic interactions, as evidenced by increased particle size, zeta potential, and endothermic peak temperature. Yogurt formulated with 2% PWP-GFP exhibited superior texture (e.g., elasticity and cohesiveness) and water-holding capacity (up to 70.12% ± 1.19% with 3% GFP). Electronic tongue and nose analyses further revealed enhanced umami and overall flavor profile. This study provides a theoretical and practical foundation for the application of natural protein-polysaccharide complexes in high-quality dairy products.