Metabolomic insights into the quality of purple-leaf black tea: Impact of purple pigmentation on aroma, flavor, and bioactive compounds.

This study explores the quality differences between purple-leaf black teas (FoShou, DaYeLong, ZiJuan) and green-leaf black tea (ZhuYeQi) through sensory evaluation, electronic sensory analysis, targeted metabolomics, dose-over-threshold (DOT) analysis, volatile metabolomics, odor activity value (OAV) analysis, and molecular docking. Purple-leaf black teas exhibit deeper orange infusions, complex floral-fruity aromas, and fresher, sweeter tastes, with ZiJuan scoring the highest overall. Targeted metabolomics identified 200 non-volatile metabolites (NVMs), DOT analysis highlighting key taste-related compounds such as glutamic acid, theaflavins, and flavonoid glycosides. GC-MS detected 169 volatile metabolites (VMs) were detected, with terpenoids, esters, and alkanes as dominant groups. OAV and correlation analysis identified β-ionone, linalool, and geraniol as major contributors to woody-floral aromas. Molecular docking implyed theaflavin's strong binding to umami receptors and δ-cadinene's affinity for olfactory receptors. These findings provide molecular insights into the quality attributes of purple-leaf black tea, with implications for future optimization and digital sensory evaluation.