Metabolomics, sensory evaluation, and enzymatic hydrolysis reveal the effect of storage on the critical astringency-active components of crude Pu-erh tea

•Five year storage is critical point for components and taste of crude pu-erh tea.•Gallotannins are marker compounds for storage of crude pu-erh tea.•Galloylated catechins are responsible for taste changes of tea infusion.•Flavonol glycosides contribute less to the astringency of crude pu-erh tea infusion.