Impact of Origin on the Taste of Wuniuzao (Camellia sinensis) Flat Green Tea: Integrated Metabolomics and Quantitative Analysis

Flat green tea is highly favored by consumers for its distinctive appearance and flavor. The tea variety Wuniuzao ( Camellia sinensis ) is particularly suitable for producing high-quality flat green tea. Wuniuzao harvested from various geographic origins was used as raw material to produce flat green tea. We systematically compared the tastes of tea liquor, major quality components, and nonvolatile metabolites of Wuniuzao flat green tea (WFGT) according to the different origins. Caffeine levels and the composition and content of catechins significantly differed among origins, representing a major factor underlying regional flavor differences in WFGT. Untargeted metabolomics analysis identified 94 key differential metabolites and showed flavonoids represent the largest proportion, indicating that flavonoid-rich samples may exhibit enhanced bioactivity and potential health benefits. Overall, this study elucidated the impact of geographic origin on WFGT quality characteristics. • Caffeine and catechins are important chemical fingerprints for different origins. • 94 nonvolatile key differential metabolites were detected totally. • 25 flavonoids are the most abundant key differential metabolites.