Isolation, taste characterization and molecular docking study of novel umami peptides from Lactarius volemus (Fr.)

This study aimed to understand the tasty flavor of wild Lactarius volemus (Fr.). The umami peptides from its aqueous extraction were purified by ultrafiltration, Sephadex G-25 gel filtration chromatography, and reversed-phase high-performance liquid chromatography. Sensory evaluation was used to identify the peptide fraction with the intense umami taste, and the peptides in the fraction were identified. Four umami peptides, namely EVAEALDAPKTT, AVLEEAQKVELK, AEDLSTLR, and KVDVDSLK, were virtually selected by molecular docking and umami taste active fragment frequency. The sensory evaluation and electronic tongue revealed that four screened peptides had umami taste features with umami identification thresholds in the range of 0.0625-0.250 mg/mL. Molecular docking results showed that the four umami peptides could be embedded into the binding pocket of the taste receptor T1R3 cavity. The major interactions forces were hydrogen bonding and hydrophobic interactions, and the key sites for T1R3 binding were Glu217, Glu148, and Glu45.