Identification, taste characterization, and molecular docking study of a novel microbiota-derived umami peptide

Umami peptides are an important taste substance in fermented foods. However, in the absence of known microbiota-derived umami peptides, the understanding of the umami mechanism remains unclear. Tetrageno-coccus halophilus, a dominant fermentation bacteria, may be an important source of umami peptides. Accord-ingly, T. halophilus fermentation broth was fractioned by ethanol precipitation, gel chromatography, and reverse phase-high performance liquid chromatography. The isolated peptide fraction with the most intense umami taste was screened by amino acid composition and sensory analyses. Finally, three novel microbiota-derived peptides (DFE, LAGE, and QLQ) were identified, synthesized, and characterized for taste. Among them, only DFE had umami and umami-enhancing abilities improving multiple tastes. Molecular docking studies indicated that DEF binds to T1R1/T1R3 receptors through hydrogen bonding and electrostatic interactions involving receptor res-idues Ser332, Ser256, ASN41, His125, etc. This study highlights the critical role of microbiota-derived peptides in the umami taste of fermented foods.

Automated summary

Umami peptides are important taste substances in fermented foods. The understanding of umami mechanism is unclear due to the absence of known microbiota-derived umami peptides. Tetragenococcus halophilus, a dominant fermentation bacteria, was found to be a potential source of umami peptides. Three novel microbiota-derived peptides (DFE, LAGE, and QLQ) were identified and only DFE had umami and umami-enhancing abilities. Molecular docking studies revealed that DFE binds to T1R1/T1R3 receptors through hydrogen bonding and electrostatic interactions. This study highlights the critical role of microbiota-derived peptides in the umami taste of fermented foods.