Effects of deamidation by protein glutaminase on the flavor binding properties of pea protein isolate

This study aimed to investigate the effects of protein deamidation by protein glutaminase (PG) on the flavor binding properties of pea protein isolate (PPI), using vanillin as a model. The binding behaviors of native PPI and deamidated PPI were assessed at different temperatures (5–25 °C). The results showed that the number of binding sites ( n ) increases with decreasing temperature. In addition, the binding constant ( K ) and overall binding ( nK ) are considerably lower after deamidation. Thermodynamic analysis revealed negative ∆ G ° values for both proteins, confirming spontaneous binding. Additionally, positive ∆ H ° and ∆ S ° values suggested that the interactions are entropy-driven and primarily hydrophobic in nature, which was confirmed using molecular docking studies, with stronger bonding to vanillin observed for PPI than for deamidated PPI. Sensory evaluation revealed that deamidation promoted flavor release. Thus, PG deamidation enhances flavor delivery performance, positioning deamidated PPI as promising protein-based component for improving flavor interactions in food applications.