Identification of markers for tea authenticity assessment: Non-targeted metabolomics of highly similar oolong tea cultivars (Camellia sinensis var. sinensis)

Tea authenticity assessment remains a challenge because of various cultivars and similar chemical profiles among tea cultivars. Unique oolong tea cultivars (YaShiXiang (YSX)) were used as models in the present study to identify potential markers for tea authenticity assessment via non-targeted metabolomics. With chemometric analysis, a total of ten markers were found to differ significantly among YSX and the high similarity cultivar tea samples, which were up-regulated in YSX. Based on the ten markers, classification model for discrimination of YSX were developed with different combinations of markers. All models were able to classify YSX samples correctly (93.0%–100% for internal cross-validation; 80.5%–99.0% for external validation). The simultaneous determination of metabolites in this study suggested that a combination of non-targeted metabolomics and chemometric methods could provide high resolution markers for tea authenticity assessment, and which can serve as a basis for further quality evaluation and breeding of tea cultivars in the future. • Highly similar oolong tea cultivars were analyzed for tea authenticity assessment. • Chemical composition of tea were analyzed by UHPLC Q-Exative Orbitrap MS. • Ten markers were identified to evaluate the authenticity of oolong tea.