Abstract:[Objective]This study aims to investigate the effects of different withering methods on the quality of Wuyi rock tea produced from rain-soaked leaves.[Method]The rain-soaked leaves of Wuyi Shuixian (Camellia sinensis) were treated with three withering methods: comprehensive withering in a fermentation machine, natural withering, and withering in an automated withering equipment. Sensory evaluation, biochemical component detection, and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry were employed to comparatively analyze the flavor compounds.[Result]The tea samples processed by the automated withering equipment (PW) exhibited the highest overall quality, characterized by a rich floral and fruity aroma, as well as a mellow, brisk, and refreshing taste. Cluster analysis combined with the variable importance in projection (VIP) of orthogonal partial least squares-discriminant analysis (OPLS-DA) identified six key flavor compounds significantly contributing to the tea infusion. The PW showed higher mass fractions of water extracts, tea polyphenols, and free amino acids. Additionally, 15 key aroma compounds with VIP>1 and odor activity value (OAV)>1 were identified as critical differential aroma compounds. Compounds such as indole, α-farnesene, and 6-methyl-5-hepten-2-one had high mass fractions in the PW, contributing significantly to their floral and fruity aroma. The naturally withered samples (SW) exhibited an intermediate total mass fraction of aroma compounds, while the comprehensively withered samples (CK) had lower total mass fraction of aroma compounds and mass fractions of key aroma compounds, along with higher mass fraction of hexanal (imparting a grassy odor), demonstrating a distinct dull green taste.[Conclusion]The study demonstrates that automated withering equipment significantly enhances the quality of Wuyi rock tea produced from rain-soaked leaves, providing a theoretical basis for the quality control and the broader application of this novel withering technology.
