Multi-scale quality evaluation and geographical origins discrimination of Ankang green tea by intelligent sensory analysis, selenium elemental analysis and quantitative non-volatile sensometabolomics.

To date, no comprehensive study has explored the multi-dimensional quality of Ankang selenium-enriched green tea. Herein, 61 Ankang tea samples from four small-scale geographical origins were analyzed using a novel multi-analytical approach combining intelligent sensory evaluation, selenium quantification, and sensometabolomics. Selenium content differed across regions. 89 non-volatiles were absolutely quantified. Flavan-3-ols were most abundant (493.79-1317.04 mg/L), followed by amino acids (406.18-940.11 mg/L), phenolic acids (364.66-901.33 mg/L), alkaloids (355.44-688.72 mg/L), organic acids (121.08-556.10 mg/L), sugars (105.88-511.91 mg/L), flavone/flavonol and glycosides (0.62-48.48 mg/L). Epigallocatechin gallate (EGCG), theanine, theogallin, caffeine, citric acid, maltose, and kaempferol-3-O-glucosylrutinoside were most predominant within each class. Dose-over-threshold (DOT) based taste contribution analysis showed 10 compounds with DOT>1, highlighting rutin, theogallin, EGCG and caffeine as prominent contributors (DOT = 2036.82, 10.44, 7.28, 5.31, respectively). 43 key differential compounds and distinct DOT in astringency, bitterness and umami was revealed across regions. Moreover, the correlation between differential metabolites, selenium, and taste indexes was explored.