不同萎凋方式对“雨水青”武夷岩茶品质的影响

Influences of Different Withering Methods on the Quality of Wuyi Rock Tea Produced from Rain-soaked Leaves

摘要:

【目的】探究不同萎凋方式对“雨水青”武夷岩茶品质的影响。【方法】以“雨水青”武夷水仙茶为研究对象，采用综合做青机萎凋、自然萎凋和自动化萎凋设备萎凋3种方式制作武夷岩茶。通过感官审评、生化成分检测、顶空固相微萃取结合气相色谱-质谱联用等方法对比分析其风味物质。【结果】自动化萎凋设备所制样品（PW）综合品质最佳，具有花果香浓郁、滋味浓醇爽口等特点。结合聚类分析与正交偏最小二乘判别分析（orthogonal partial least squaresdiscrimination analysis，OPLS-DA）的变量重要性投影（VIP），筛选出6种对茶汤有显著贡献的呈味物质。其中，PW的水浸出物、茶多酚、游离氨基酸等的质量分数均较高。根据VIP>1且气味活度值（odor activity value，OAV）>1，筛选出15种影响香气的关键差异化合物，其中，吲哚、α-法尼烯、6-甲基-5-庚烯-2-酮等的质量分数在PW中较高，对花果香具有突出贡献。自然萎凋所制样品（SW）香气化合物总质量分数适中；综合做青机萎凋所制样品（CK）香气化合物总质量分数及关键香气化合物质量分数较低，且具有青草气的正己醛质量分数较高，呈现明显闷青味。【结论】自动化萎凋设备显著提升了“雨水青”武夷岩茶的品质，为“雨水青”武夷岩茶的质量控制及该新式萎凋设备的推广应用提供了理论依据。

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.