Molecular interactions and gelation of polymerized whey protein-Armillaria mellea polysaccharide hydrogel and its application in yogurt

This study investigated the interaction mechanism between polymerized whey protein (PWP) and Armillaria mellea polysaccharide (AMP) and its application as a natural thickener in yogurt. Composite hydrogels with varying AMP content (0-6 %) were characterized using simultaneous rheology-FTIR, 2D-COS, and molecular docking. Results revealed that AMP enhanced the gel network via hydrogen bonding, hydrophobic, and electrostatic interactions, significantly improving thermal stability (denaturation temperature increased from 86.38 °C to 103.58 °C), mechanical strength, and antioxidant capacity (DPPH and ABTS radical scavenging rates reached 37.73 % and 75.40 %, respectively). Yogurt formulated with 6 % AMP-PWP hydrogel exhibited superior texture, with hardness, gumminess, and chewiness, and a water holding capacity of 62.95 % at 4.5 % AMP. It can also improve the sensory properties of yogurt. The hydrogel also contributed to a denser microstructure and enhanced viscoelastic properties. This work provides a theoretical foundation for protein-polysaccharide gel design and demonstrates the potential of PWP-AMP as a novel, natural yogurt texture modifier.