The molecular properties and potential interactions with TMC4 of salt taste-enhancing peptides derived from spent hen meat

Salt taste-enhancing peptides (STEP) are promising alternatives for sodium reduction in food systems. 27 peptides from spent hen hydrolyzates exhibited significant salt taste-enhancing activity (STEA). Dipeptides containing Arg/Asp residues displayed higher STEA, particularly for DE, DR, and AR. Partial least squares regression analysis identified fractional partial positive surface area, charge, and conformational flexibility as important characteristics associated with the activity of STEP. STEA increased with increasing pH, suggesting that the ionic form of peptides may influence their saltiness perception. Molecular simulation analysis of DE, DR, and AR indicated that the potential interactions with TMC4, primarily involving hydrogen-bond and electrostatic interactions with key residues Arg294, Arg580, Arg583, Glu319, and Glu323. Furthermore, density functional theory calculations revealed differences in electrostatic potential distribution among DE, DR, and AR, which may be related to their different interaction patterns with TMC4 and differences in STEA. These results provided insights into the relationships between peptide structure, interaction with TMC4, and STEA, and provided a basis for further experimental investigation of the molecular mechanisms underlying salt taste enhancement of STEP.