Discovery of novel umami-enhancing peptides in enzymatic hydrolyzed walnut meal protein and evaluation of their umami-enhancing effect and mechanism.

This study assessed the capacity of peptides generated from walnut meal proteins to enhance umami perception. Through single-factor optimization, ultrafiltration, and ethanol precipitation, walnut meal protein hydrolysates with pronounced umami intensity were produced. An integrated virtual screening strategy then yielded eleven umami peptides candidate, whose umami-enhancing effects were assessed by sensory evaluations and electronic tongue. Among these candidates, incorporating the peptides DGFE, GPRAAP, GDPGW, and DDNFLDF into monosodium glutamate (MSG) solutions (3, 6, and 9 mg/mL) enhanced umami intensity by 15.22% to 119.35% and extended the umami duration by 20.00% to 66.67%, demonstrating synergistic or additive effects. Molecular docking showed that these umami-enhancing peptides enhanced the binding between MSG and T1R1/T1R3 receptor by improving binding affinity and increasing both the number and diversity of interaction forces, thereby intensifying umami perception. Moreover, molecular dynamics simulations confirmed the role of these umami-enhancing peptides in stabilizing and enhancing the binding between MSG and the T1R1/T1R3 receptor complex. These findings broaden the repository of umami-enhancing peptides applicable as food additives and enhance the utilization of walnut meal proteins.