UPLC-Q-TOF-MS based metabolomics and chemometric analyses for green tea fermented with Saccharomyces boulardii CNCM I-745 and Lactiplantibacillus plantarum 299V

UPLC-Q-TOF-MS was employed to analyse the non-volatile components of green teas fermented with probiotic yeast (Saccharomyces boulardii) and lactic acid bacteria (LAB, Lactiplantibacillus plantarum). The flavone glycosides in yeast-fermented and stored tea decreased significantly, together with the increases of flavone aglycones and other simple flavone glycosides. LAB-fermented tea presented different flavone glycoside profiles; in which, both C-glycosides and O-glycosides decreased and the flavone aglycones were further degraded. The profiles of flavone glycosides and aglycones in co-cultured tea differed from that in yeast- or LAB-fermented tea; less glycosides were degraded but a greater number of aglycones were produced. Two unique LAB metabolites with bioactive and antifungal properties, D-phenyllactic acid (PLA) and p-OH-PLA, were found in both L. plantarum and co-cultured teas, and the co-fermentation showed a synergic effect on the production of these two compounds that would enhance the quality and preservation of fermented teas.

Automated summary

UPLC-Q-TOF-MS was used to analyze the non-volatile components of green teas fermented with probiotic yeast and lactic acid bacteria. The study found changes in flavone glycosides and flavone aglycones, as well as the production of two bioactive LAB metabolites in co-cultured teas.