Discovery of Rice Bran Protein-Derived Umami Peptides with Saltiness-Enhancing Properties: Multisensory Evaluation, Integrated Virtual Screening, and Computational Simulation

Developing natural saltiness-enhancing peptides offers a feasible approach to dietary sodium reduction; however, the high-value use of sustainable agricultural byproducts for taste modulation remains underexplored. In this study, four saltiness-enhancing peptides (FGGEL, EGPDF, DGHAAF, and EGMF) were identified from rice-bran protein through virtual screening and multisensory evaluation. A 3 mg/mL sodium chloride solution served as the control. These peptides exhibited synergistic or additive effects, increasing NaCl saltiness intensity by 39.62-67.92% and extending saltiness duration by 50-100%. They also increased salivary aldosterone levels, which may contribute to an enhanced physiological sensitivity to saltiness. Computational analyses, including molecular docking, molecular dynamics, and density functional theory, suggested that a low electrostatic potential favors stable hydrogen-bond formation between the peptides and the TMC4 receptor. Collectively, these findings provide a theoretical and technical basis for developing natural, sodium-reduced ingredients with saltiness-enhancing functions based on rice-bran protein.