A study on the dynamic differences and component correlations of astringency in green tea, black tea and oolong tea based on TI/TDS and LC-MS.

The dynamic patterns and chemical drivers of astringency across tea varieties remain underexplored. This study integrated time-intensity (TI), temporal dominance of sensations (TDS), electronic tongue, and LC-MS analyses to evaluate astringency in six green, black, and oolong teas. TI results indicated that green tea exhibited higher peak intensity, larger area under the curve (AUC), longer duration, and faster onset compared to oolong and black teas. TDS analysis revealed dominant sensations: "harsh" and "coarse grain" for green tea, "smooth" and "dry" for black tea, and alternating "rough" and "dry" for oolong tea. LC-MS profiling linked high astringency to anthocyanins, quercetin derivatives, and catechin oxidation products. Roughness correlated with polymerized catechins, granularity with flavanols, and dryness with oxidized polyphenols. Overall, polyphenol type and structure are key determinants of astringency intensity and sub-quality variations among tea types.