Changes In Sensory Characteristics, Chemical Composition And Microbial Succession During Fermentation of Ancient Plants Pu-Erh Tea

Abstract

“Ancient tea plants” are defined as tea trees>100 years old, or with a trunk diameter > 25 cm; their leaves are sun-dried into green tea, which is then processed by natural fermentation into high-quality, valuable pu-erh tea. In this study, changes in sensory characteristics, chemical composition and microbial succession during Ancient Plants Pu-erh tea (APPT) fermentation were investigated. Fermentation was characterized by outstanding sweetness of APPT infusion. The content of soluble sugars and theabrownins increased (p < 0.05). In addition, the relative levels of 72 metabolites decreased, based on Variable importance in projection (VIP) >1.0, p < 0.05 and Fold-change (FC) < 0.5, whereas those of 41 metabolites increased (VIP >1.0, p < 0.05, FC >2). Three bacterial and five fungal genera were identified as dominant (relative abundance >1%), and their correlated with characteristic components (p < 0.05). These findings advance knowledge of the formation mechanism of APPT unique quality.

Keywords: Ancient plants pu-erh tea, Pile-fermentation, Sensory characteristics, chemical composition, Microbial succession