Decoding tea flavor: Metabolomic insights into three tea cultivars

By analyzing apical buds and first leaves using widely targeted metabolomics, researchers identified 505 metabolites, shedding light on the biochemical basis for variations in tea bitterness, aroma, and umami flavor. While SCZ and ZJ were rich in catechins and anthocyanins contributing to astringency and bitterness, HK stood out for its higher content of pleasant-tasting amino acids like L-theanine.

Tea (Camellia sinensis) is cherished globally for its diverse flavors and health benefits, which stem from its rich profile of secondary metabolites—particularly flavonoids, amino acids, and lipids. Flavan-3-ols like EGCG are known to drive bitterness and astringency, while amino acids such as L-theanine contribute to umami and mellow sweetness. Lipid-derived volatiles also play a crucial role in aroma. Although the metabolites in tea have been studied extensively, little is known about how these compounds vary in biosynthesis and distribution across different cultivars and tissues. Given China's rich germplasm diversity, deeper metabolic profiling is vital for understanding tea flavor complexity and guiding cultivar development.

A study (DOI: 10.48130/bpr-0024-0012) published in Beverage Plant Research on 04 July 2024 by Liang Chen’s team, Tea Research Institute, Chinese Academy of Agricultural Sciences, offers a comprehensive molecular map for understanding cultivar-specific tea quality and opens new paths for precision tea breeding.

To explore the metabolite diversity and quality-related compounds in tea, researchers applied widely targeted metabolomics to analyze the apical buds and first leaves of three tea cultivars: green SCZ, yellow HK, and purple ZJ. A total of 505 metabolites were identified and classified into ten categories, with flavonoids comprising the largest proportion (38.03%). Principal component analysis (PCA) revealed clear separation between cultivars and tissue types, confirming distinct metabolic profiles. Further multivariate modeling (OPLS-DA) demonstrated strong predictive power (Q² > 0.99) and identified significant differences between samples. Volcano plot screening highlighted flavonoids as the most differential metabolites among cultivars. Detailed cluster analysis showed that SCZ had the highest levels of flavan-3-ols such as EGCG and EC, which contribute to tea’s astringency and bitterness. In contrast, ZJ accumulated abundant anthocyanin glycosides and flavonol glycosides, compounds responsible for both purple pigmentation and flavor intensity. HK, while lower in flavonoids, exhibited the highest accumulation of L-theanine and other free amino acids—particularly in apical buds—suggesting a smoother, umami-rich taste profile. Lipid analysis showed that ZJ apical buds contained the highest lipid concentrations, potentially enhancing aromatic qualities. Overall, metabolite accumulation patterns were cultivar- and tissue-specific, offering critical insights into the molecular basis of tea flavor, color, and aroma.

This study provides a valuable reference for tea breeders aiming to optimize taste and aroma through targeted metabolite selection. By linking chemical markers like L-theanine or anthocyanins to flavor qualities, breeders can screen and develop cultivars tailored to specific sensory profiles. The insights also benefit tea processors and consumers by offering a deeper understanding of how leaf part and cultivar affect final tea flavor. In the future, integrating transcriptomics with metabolomics could uncover the gene-level controls driving metabolite accumulation, enabling even finer manipulation of tea quality.

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References

DOI

10.48130/bpr-0024-0012

Original Source URL

https://doi.org/10.48130/bpr-0024-0012

Funding information

This work was supported by the Hainan Province postdoctoral surface funding project (RZ2300001314), the National Natural Science Foundation of China (U19A2030, 32072631), the China Agricultural Research System of MOF and MARA (CARS-019), and the Chinese Academy of Agricultural Sciences through the Agricultural Science and Technology Innovation Program (CAAS-ASTIP-2021-TRICAAS) to LC.

About Beverage Plant Research

Beverage Plant Research (e-ISSN 2769-2108) is the official journal of Tea Research Institute, Chinese Academy of Agricultural Sciences and China Tea Science Society. Beverage Plant Research is an open-access, online-only journal published by Maximum Academic Press. Beverage Plant Research publishes original research, methods, reviews, editorials, and perspectives that advance the biology, chemistry, processing, and health functions of tea and other important beverage plants.