Identification and taste characteristics of novel salt taste-enhancing peptides from defatted Antarctic krill (Euphausia superba) powder hydrolysate and their molecular mechanisms of interaction with the TMC4 channel.

This study aimed to prepare and identify novel salt taste-enhancing peptides from defatted Antarctic krill (Euphausia superba) powder hydrolysate (DAKPH), and investigate molecular mechanisms. Six potential peptides were screened via virtual screening from 36,014 peptides identified through UHPLC-MS/MS. Sensory evaluation and electronic tongue analysis verified that 0.4 mg/mL EDLEY, WDDDP, EDYEF, ERDY, and DRPWE significantly enhanced the salt taste perception of 3 mg/mL NaCl (p < 0.05). Molecular docking and molecular dynamics simulation results indicated that these five peptides entered the binding pocket of transmembrane channel-like 4 (TMC4), wherein hydrogen bonds were the main binding forces and Arg residues were the key binding sites. The salt taste-enhancing effects of peptides exhibited a very strong positive correlation with hydrogen bond proportions (r = 0.99 and 0.95 for the sensory evaluation and electronic tongue results, respectively) but a very strong negative correlation with hydrophobic interaction proportions (r = -0.90 and - 0.88 for the sensory evaluation and electronic tongue results, respectively) (p < 0.05). This study proposes novel insights into the structure-activity relationship of salt taste-enhancing peptides.