Linking chemical profiles to sensory quality: Insights into color and taste formation in purple leaf tea infusions

Abstract

Purple leaf tea (PLT) infusions typically exhibit a distinctive purplish-red hue and bitter taste, yet their chemical-sensory links remain underexplored. We profiled 177 metabolites from sixteen green to deep purple tea accessions, with partial least squares discriminant analysis and random forest subsequently highlighting 27 differential metabolites. Multivariate analysis highlighted acylated anthocyanins, specifically delphinidin and cyanidin derivatives, as key markers linked to redness and bitterness. Photodiode array detection confirmed these pigments as primary chromophores. Crucially, addition experiments validated that specific anthocyanin ratios govern color shifts, while their accumulation significantly intensifies bitterness and astringency. Molecular docking further supported this sensory impact, revealing that acylation enhances anthocyanin binding to human bitter receptor TAS2R14 through hydrogen bonding and π-π stacking interactions. These findings link flavonoid pathway reprogramming to the chromatic and sensory divergence of PLT, offering molecular targets for breeding high-pigment, palatable tea cultivars.

Keywords: Acylated anthocyanins; Color formation; Metabolomics; Purple leaf tea; Taste modulation.