Umami characterization and molecular simulation of novel peptides from Pleurotus citrinopileatus Singer bromelain hydrolysate.

Pleurotus citrinopileatus Singer is the promising precursor of umami peptides. This study aimed to isolate P. citrinopileatus Singer-derived umami peptides, and then explore their taste characteristics and umami mechanism. Four novel umami peptides (LLVTVEDELRV, LDDWR, ELFEPT, and ENLLEK) were separated and identified from bromelain hydrolysate, and then predicted their umami potentials through umami fragment frequencies and T1R1/T1R3 receptor docking. Their umami characteristics were subsequently confirmed in sensory evaluation and electronic tongue verification. Particularly, LLVTVEDELRV (0.0625 mg/mL) and LDDWR (0.1250 mg/mL) exhibited potent umami taste, with significant lower thresholds than monosodium glutamate. Molecular docking analysis revealed that all four peptides could bind to T1R1/T1R3 receptor, and hydrogen bonding and hydrophobic interactions were the dominant interaction forces. Asp219 and Glu148 residues were of great significance in the interactions of peptides ligand to T1R3. Furthermore, all of them exhibited umami enhancement in simulated broth solutions.