Metabolomics-based analysis of the effects of differences in soluble sugars on the sweetness quality of six major tea types in China

Soluble sugars are indeed key factors in the formation of tea sweetness quality. However, the specific impact they exert on tea sweetness has not been clearly elucidated. Consequently, in this study, one bud and two leaves of the same tea variety were utilized to produce six types of tea for sensory evaluation, electronic tongue analysis, and targeted sugar metabolomics analysis, aiming to systematically assess the influence of soluble sugars on the sweetness contribution in different teas. The results obtained from sensory evaluation and the electronic tongue indicate that the sweetness order of various teas is green tea (GT) > yellow tea (YT) > dark tea (DT) > oolong tea (OT) > black tea (BT) > white tea (WT). Through metabolomics, 26 crucial differential metabolites were identified, among which sucrose, inositol, D-fructose, glucose, and D-arabinitol constitute the main sugar components that distinguish the sweetness characteristics of the six types of tea. This study offers a comprehensive and detailed overview of the effects of commonly employed processing methods on the sweetness quality of tea as well as its metabolic properties. It thereby lays a solid theoretical foundation for optimizing processing techniques to enhance the sweetness quality of tea and to better serve tea production practices.