Study on the Dynamics of Differential Metabolites of Pu-erh Tea Fermented by Exogenous Added Bacteria

In order to explore the role of exogenous bacteria in the fermentation process of Pu-erh tea and its impact on tea quality, the present study aimed to explore the differences in metabolite changes during fermentation of Pu-erh tea treated with different bacterial strains. To achieve this, non-targeted metabolomics technology was employed, which was combined with multivariate statistical analysis and differential heat maps. The study analyzed the flavonoids, alkaloids, and terpenoids present in the tea samples. The H group was found to have a fruity and sweet aroma, a bright red soup color, and a strong and sweet taste. The A group had a strong floral and honey aroma, a bright red soup color, and a strong and sweet aftertaste. The R group had a fruity and milky aroma, a bright yellow soup color, and a strong but astringent and bitter taste. These differences in quality were found to be related to the levels of metabolites such as malvidin, genkwanin, catechins, caffeine, and lactucin. The study provided preliminary insights into the differences in metabolite content during the fermentation of Pu-erh tea with different bacterial strains, which can have varying effects on the taste, aroma, and soup color of the tea. The findings of this study could provide theoretical assistance for future Pu-erh tea fermentation.