Effects of Shaking and Withering Processes on the Aroma Qualities of Black Tea

Combined withering and shaking processes are key steps in the formation of characteristic floral and fruity aromas in black teas. However, the effect of the sequencing of withering and shaking on volatile compounds and aroma formation in black tea has not been evaluated to date. This study used headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry to detect volatile compounds in black teas after withering-shaking and shaking-withering processing. Five main differentially volatile components were screened out by partial least squares discriminant analysis and odor activity value analysis, which were 3-carene, geraniol, β-myrcene, τ-cadinol, and β-ionone. Additionally, sensory evaluation showed black tea produced by withering-shaking was fruitier, while shaking-withering produced a more floral tea. This study provides a theoretical basis for the discrimination of aroma characteristics of black tea processed by shaking, as well as a technical guide for the precise production of black teas with different floral-fruity aroma biases.