Unraveling novel umami-enhancing peptides in rice bran protein and its umami-enhancing mechanism by multisensory evaluation and computational simulation

This study explored the potential of rice bran protein-derived peptides to enhance umami perception. By applying single-factor optimization, ultrafiltration, and ethanol precipitation, rice bran protein hydrolysates with pronounced umami intensity were prepared. An integrated virtual screening workflow identified ten candidate umami peptides, whose umami-enhancing effects were quantified by sensory evaluation (quantitative descriptive analysis, time-intensity, and S-shaped curve) and electronic tongue. Among them, TDPF, DPDWL, WGDP, and LDGF, when added to monosodium glutamate (MSG) solutions at 3, 6, and 9 mg/mL, increased umami intensity by 19.64-98.48% and prolonged umami duration by 20.00-44.44%, indicating additive or synergistic effects with MSG. Molecular docking suggested that these umami-enhancing peptides enhanced MSG binding to the T1R1/T1R3 receptor by increasing affinity and increasing the number and types of interactions. Molecular dynamics simulations further supported a more stable MSG-T1R1/T1R3 receptor complex in the presence of these umami-enhancing peptides. Density functional theory indicated that umami-enhancing peptides with low electrostatic potential promote binding by increasing the number and strength of hydrogen bonds. Collectively, these results expand the repertoire of umami-enhancing peptides from rice bran protein for potential use as taste enhancers and provide a basis for discovering taste compounds from this source and related matrices.