Metabolite–Peptidome Flavor Synergy and Predicted Receptor-Level Interactions in Black Tea across Diverse Cultivars

This study elucidated flavor-synergistic mechanisms of black teas from 11 diverse cultivars using sensomics, targeted metabolomics, de novo peptidomics, and AlphaFold 3 structural modeling. A total of 566 water-soluble oligopeptides and 158 modified peptides were identified, with dominant modifications including glutamine-ethylation and pyroglutamate-cyclization. Newly identified theanine-substituted peptides (e.g., EAKDEGYRQ+28.03 m/z) and glycosylated peptides may serve as potential thermal precursors during black tea processing. Their contributions to aroma formation warrant further experimental investigation. Multiligand codocking indicated that umami peptides, adenosine monophosphate, and citric acid form hydrogen bonds and interact with residues located within the modeled T1R1/T1R3 binding region (e.g., His 71, Ser 306, and Arg 307 on T1R1 at precise distances of 1.79-3.56 Å). Dual-receptor modeling suggested that specific peptides exhibited predicted binding interactions with the calcium-sensing receptor, which potentially contribute to kokumi-related perception. These findings link cultivar traits to receptor networks, offering structural and theoretical guidance for targeted modulation of tea flavor.