Identification of Key Taste-Active Compounds in Oolong Teas (Dongding and Rougui) by Quantitative Measurements, Recombination Experiments, and Omission Tests

A lack of knowledge regarding taste-active compounds of Oolong tea limits the improvement of product quality. Nontargeted metabolomics and sensory quantitative descriptive analyses were performed on two representative oolong teas, resulting in 41 compounds screened for their relevance to taste characteristics, and they were quantitated. Combined taste dose-overthreshold (DoT > 1) factors with key differentiators, reconstitution of ten selected compounds successfully replicated the authentic tea infusion. To further narrow down the number of key taste compounds, omission experiments showed that simplified reconstitution models did not differ significantly from the taste of the authentic tea infusion. Epigallocatechin gallate, caffeine (CAF), kaempferol 3-O-rutinoside (kaempferol 3-O-rut), myricetin-3-O-rutinoside (myricetin-3-O-rut), quercetin 3-arabinoside (quercetin 3-ara), quercetin 3-O-galactoside (quercetin 3-O-gal), quinic acid were the key taste compounds of Rougui tea, while CAF, kaempferol 3-O-rut, quercetin 3-ara, quercetin 3-O-gal, gallic acid, quinic acid were key compounds for Dongding tea taste. This study provides guidance for oolong tea taste improvement.