Flavonol glycosides in tea: the role of mitigating oxidative stress during the withering process

Withering is a crucial step in tea production that reduces the moisture content and induces biochemical changes in tea leaves. The withering process triggers oxidative stress by accumulating reactive oxygen species (ROS) in tea leaves. The presence of flavonol glycosides is crucial for tea quality and tea's stress response to environmental changes pre- and post-harvest. However, the role of flavonol glycosides during withering remains unexplored. The degradation of flavonol glycosides during withering is mainly attributed to the enzymatic antioxidant defense system, which produces flavonol aglycones and soluble sugars that protect leaf cells from oxidative stress. This degradation contributes to a sweeter taste and enhances the taste and aroma of tea. This review emphasizes the role of the withering process and the degradation of flavonol glycosides, highlighting their role in neutralizing ROS formation as a response to oxidative stress, and discusses how changes in flavonol glycosides contribute to the taste of tea. The importance of the withering process in the degradation of flavonol glycosides is also highlighted. Further research is needed to understand the dynamic changes of flavonol glycosides during the withering process, which is essential to improving tea quality.