Abstract:
Objective This study is aimed at uncovering the main quality traits of Jinmudan tea and the variances in quality components among different tea types (black tea, oolong tea, white tea, yellow tea, and green tea) in spring, summer, and autumn. It also explores the correlation characteristics among the main characteristic metabolites of Jinmudan tea in different tea seasons and the main metabolites that can be used to distinguish between different tea seasons.
Methods Employing black tea, oolong tea, yellow tea, white tea and green tea made from fresh leaves of 'Jinmudan' in different tea seasons as test materials, the biochemical components of tea samples were determined through conventional biochemical determination, high performance liquid chromatography and mass linking of AQC derivatives.
Results The content of tea polyphenols and catechins in Jinmudan summer tea is significantly higher than that in other seasons. In contrast, the amino acid content is highest in spring tea and lowest in summer tea. The catechin composition of Jinmudan tea is dominated by EGC, EGCG, ECG, and GC. Correlation analysis indicates that seasonal factors have a significant impact on the chemical composition of Jinmudan tea. Based on the OPLS-DA discriminant model, 12, 15, 15, 17, and 17 differential metabolites were screened from Jinmudan black tea, oolong tea, white tea, yellow tea, and green tea, respectively, across different seasons. These metabolites can serve as potential markers for distinguishing spring, summer, and autumn teas.
Conclusion This study clarified the chemical characteristics of taste quality in Jinmudan tea across different tea types and seasons, and reveals the variation patterns of its major characteristic metabolites in different tea seasons. It provides a scientific basis for improving the utilization rate of Jinmudan fresh tea leaves and optimizing the quality of Jinmudan tea.
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