Untargeted metabolomics reveals differences between commercial and non-commercial Camellia sinensis cultivars used in black tea production

Abstract

Tea (Camellia sinensis) has enthralled both consumers and researchers, and its popularity has increased, due to its taste, aroma and its medicinal attributes, owed largely to its metabolites.The catechins and theaflavins in green and black tea, respectively, have been documented to possess anti-oxidant, anti-inflammatory, anti-cancer, as well as cardiovascular diseasepreventing properties. Tea consumers concern themselves with the quality of tea, in particular, its taste and aroma based on which consumers are willing to pay premium prices for the best quality teas. In turn, the quality of tea is undeniably affected by variations in its metabolite composition. In this study, two groups of black tea cultivars, one commercial and the second non-commercial, were compared using a metabolomics approach. Data were generated via untargeted GC-MS and semi-targeted 1 H-NMR. The GC-MS results differentiated between the two groups, based on arabinose, sucrose, phloroglucinol and xylonic acid. The 1 H-NMR results differentiated between the two groups, based on caffeine, catechin, EC, EGC, and the amino acids alanine, isoleucine, leucine, theanine, and valine. These metabolites applicability in the discrimination of newly developed cultivars into potentially commercialisable and non-commercialisable groups at an early stage in the tea improvement programme is demonstrated. This information may also help tea breeders to select promising high quality black and drought tolerant improved tea cultivars either for release or further field evaluations.

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

“…The method for metabolite extraction determined the quality of results. Organic solvents such as methanol, ethanol and acetonitrile are mainly used as the extraction solvents (Nyarukowa et al ., 2021; Li et al ., 2022c). Applying these solvents with new technologies such as headspace solid‐phase microextraction (HS‐SPME), ultrasound extraction, membrane separation technology and supercritical fluid extraction is more efficient and accurate compared with traditional solid–liquid and liquid–liquid extraction (Cai et al ., 2021).…”

“…Theaflavins produced by catechin oxidation is an important colouring substance in fermented tea, which provides freshness, astringency and other flavours (Zhang et al ., 2020). Meanwhile, researchers confirmed that tea types containing high catechin content such as GW Ejulu are more suitable for making fermented tea through metabolomic analysis (Nyarukowa et al ., 2021). It is helpful to improve the quality of fermented tea by optimising the process and increasing the content of theaflavins.…”