Metabolomics in quality formation and characterisation of tea products: a review

Abstract

Summary Tea is one of the biggest categories of modern non‐alcoholic beverages with health benefits. Through different processes, tea products are divided into six main types: green tea, yellow tea, white tea, oolong tea, black tea and dark tea. Metabolomics is helpful for the comprehensive, accurate and rapid determination of tea metabolites in different types of tea products and tea processing materials. It has been widely applied in studying the relationship of tea metabolites and its quality. Therefore, it is necessary to summarise the application of metabolomics in tea. In this review, we described and summarised (1) the main metabolites of six types of tea and their implications on tea quality with emphasis on the content differences in the main metabolites in different types of tea; (2) the research on optimising the key processing steps of six types of tea based on metabolomics and the discussion of various new strategies for effectively improving their quality and (3) the advanced approach to characterise and distinguish different grades of tea products via metabolomics. The current review offers guidance for the improvement of tea quality by metabolomics and its potential challenges.

Contribution of traditional deep fermentation to volatile metabolites and odor characteristics of Wuyi rock tea

“…After withering, the tea leaves entered fermentation, which was an important link to the formation of key odor characteristics of Wuyi rock tea ( Liu et al, 2023 ). The fermentation process of Wuyi rock tea was special and complex, and the fermentation of high-quality Wuyi rock tea required 5 to 6 operations, and during each fermentation process, the transformation of substances in the tea leaves constantly intensified, which finally resulted in the formation of a special flavor of Wuyi rock tea ( Wang et al, 2020 ; Cai et al, 2022 ). During the fermentation process, the enzyme activity in tea leaves increased dramatically, and the change in enzyme activity promoted the transformation of substances in tea leaves, which was conducive to the accumulation of inclusions in tea leaves ( Zhao et al, 2022 ).…”

Untargeted metabolomics and quantification analysis reveal the shift of chemical constituents between instant dark teas individually liquid-state fermented by Aspergillus cristatus, Aspergillus niger, and Aspergillus tubingensis

“…Metabolomics is an effective tool for explaining the effects of metabolites in tea fermented by microorganisms ( Cai et al, 2022 ). Metabolomics analysis showed that certain microorganisms have important effects on the transformation of metabolites and flavor formation during pile-fermentation ( Shi et al, 2021 ; Li et al, 2022 ).…”

Comprehensive applications of metabolomics on tea science and technology: Opportunities, hurdles, and perspectives

“…From 2000 to the present, metabolomics has attracted more and more attention and been widely applied in tea industry involving cultivation, processing, as well as classification of cultivars, grades, and origins (Cai et al., 2022). Although several articles have reviewed the applications of metabolomics in tea studies, systematic and comprehensive reviews are still lacking (Cai et al., 2022; Farag et al., 2023).…”

“…From 2000 to the present, metabolomics has attracted more and more attention and been widely applied in tea industry involving cultivation, processing, as well as classification of cultivars, grades, and origins (Cai et al., 2022). Although several articles have reviewed the applications of metabolomics in tea studies, systematic and comprehensive reviews are still lacking (Cai et al., 2022; Farag et al., 2023). Hence, we carefully analyzed the published tea metabolomics articles and summarized the achievements of tea metabolomics focusing on tea metabolite variation during tea plant growth under different environmental conditions and during different processing stages, as well as metabolite differences in tea samples with different cultivars, grades, geographical origins, and tea types over the past two decades.…”

“…Therefore, gas/liquid chromatography (GC/LC), mass spectrometry (MS), nuclear magnetic resonance (NMR) spectrometry, Fourier transform infrared spectrometry (FT-IR), ultraviolet-visible spectrometry (UV-vis), and GC/LC-MS have become the most commonly used analytical instruments. From 2000 to the present, metabolomics has attracted more and more attention and been widely applied in tea industry involving cultivation, processing, as well as classification of cultivars, grades, and origins (Cai et al, 2022). Although several articles have reviewed the applications of metabolomics in tea studies, systematic and comprehensive reviews are still lacking (Cai et al, 2022;Farag et al, 2023).…”