A Comprehensive Understanding of Camellia sinensis Tea Metabolome: From Tea Plants to Processed Teas

Tea (Camellia sinensis) is one of the most popular nonalcoholic beverages in the world, second only to water. Six main types of teas are produced globally: green, white, black, oolong, yellow, and Pu-erh. Each type has a distinctive taste, quality, and cultural significance. The health-promoting effects of tea are attributed to the complex metabolite compositions present in tea leaves. These metabolite compositions vary in response to different factors. In addition to manufacturing processes in processed tea, the primary factors influencing variations of fresh tea leaf metabolites include genetics, cultivation management, and environmental conditions. Metabolomics approaches, coupled with high-throughput statistical analysis, offer promising tools for the comprehensive identification and characterization of tea leaf metabolites according to growing conditions, cultivation practices, manufacturing processes, seasonality, climate, cultivars, and geography. This review highlights the distinctive variations in fresh tea leaf metabolites, which change in response to various factors, using a metabolomics approach, which are also extended to various processed teas.