Journal of Tea Science Research, 2024, Vol.14, No.3, 134-147 http://hortherbpublisher.com/index.php/jtsr 135 adaptability but also provides a comprehensive review of current research progress and identifies potential directions for future research. This study will offer deep insights into tea science, promoting further studies and innovations in tea cultivation and production. 2 Basic Principles of Metabolomics 2.1 Key concepts and techniques in metabolomics Metabolomics is the study of the metabolome, which encompasses all small-molecule metabolites (typically less than 1 kDa) present within cells, biofluids, tissues, or organisms. This field aims to comprehensively identify and quantify these metabolites, providing insights into the biochemical activities and physiological states of biological systems. The metabolome reflects the end products of cellular processes, thus offering a snapshot of the physiological state of an organism at any given time. This makes metabolomics particularly valuable for understanding the complex interactions between genes, proteins, and environmental factors that influence cellular functions and overall health. Metabolomics encompasses various specialized fields, such as targeted metabolomics, which focuses on specific metabolite classes, and untargeted metabolomics, which aims to capture as many metabolites as possible without prior bias. Key techniques in metabolomics include mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. MS-based metabolomics, often coupled with chromatographic methods like liquid chromatography (LC) or gas chromatography (GC), offers high sensitivity and broad coverage of the metabolome (Souza et al., 2019). MS works by ionizing chemical compounds to generate charged molecules and measuring their mass-to-charge ratios, which allows for the precise identification and quantification of metabolites. On the other hand, NMR spectroscopy provides robust, reproducible data on metabolite structures based on their resonance behaviors in a magnetic field, which is modulated by the surrounding chemical structure (Newsom and McCall, 2018). NMR is particularly useful for determining the structure of complex molecules and for studies where sample integrity and non-destructive analysis are crucial. These techniques are complemented by advanced bioinformatics tools that facilitate data processing, metabolite identification, and the integration of metabolomics data with other omics datasets, providing a holistic view of metabolic pathways and networks. 2.2 Application of metabolomics in tea research Metabolomics has been extensively applied in tea research to understand the complex biochemical makeup and variations within tea plants (Camellia sinensis). This technology helps in profiling and quantifying a vast array of metabolites that contribute to tea's quality, flavor, and health benefits. One significant application of metabolomics in tea research is in the evaluation of tea quality. By analyzing the metabolic profiles of tea leaves, researchers can identify key bioactive compounds such as catechins, theaflavins, amino acids, and alkaloids. These compounds are crucial for determining the sensory properties and health effects of tea. For instance, the catechins, particularly epigallocatechin gallate (EGCG), are known for their antioxidant properties and health benefits (Jiang et al., 2019). Metabolomics also aids in understanding how different environmental conditions affect the metabolic profile of tea plants. Factors such as soil type, altitude, climate, and horticultural practices can significantly influence the concentration and composition of metabolites in tea leaves. Studies have shown that environmental stresses, both biotic and abiotic, lead to variations in metabolite levels, which in turn affect the quality and flavor of the tea produced (Wen et al., 2023). Different processing techniques, such as fermentation, withering, and drying, can alter the chemical composition of tea leaves. Metabolomics has been employed to study these changes, providing insights into how processing affects the levels of various metabolites. For example, the withering process has been shown to increase the levels of certain amino acids and flavonoids, enhancing the flavor profile of white tea (Chen et al., 2020). Furthermore, metabolomics helps in identifying and understanding the metabolic pathways involved in the biosynthesis of key tea metabolites. By integrating metabolomic data with transcriptomic and proteomic analyses,
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