Objective Aromatics of traditional Tanyang Gongfu black teas made from the leaves of different varieties of tea cultivars were analyzed.
Method One bud and two or three leaves of 'Jin Mudan', 'Mingke No. 1'(Jin Guanyin), 'Tanyang Caicha', 'Fu'an Dabaicha', and 'Meizhan' teas were used for the study. Following the primary traditional Tanyang Gongfu black tea process, the prototype products were made and subjected to the simultaneous distillation extraction (SDE) and followed by a chemical analysis using the gas chromatography-mass spectrometry (GC-MS). The analytical results were correlated with the sensory evaluation scores on the brewed teas.
Result One-hundred-and-nine volatile compounds were identified in the 5 black tea samples. Among them, Jin Mudan tea had the most, up to 52, different substances. Quantitatively, alcohols were the most and followed by esters, aldehydes, and others. The highest relative content of geraniol at 48.13% was found in Jin Guanyin tea; those of linalool at 22.97% and nonanal at 12.82% in Meizhan; that of terpineol at 1.78% in Tanyang caicha; and that of 3,7-dimethyl-1,5,7-octen-3-ol at 11.66% in Fu'an Dabaicha. All varieties of the teas contained geraniol or its isomers, linalool, and other major aromatics. All brewed teas were fragrant, however, the floral and fruity notes of Jin Mudan tea stood out among them. The cluster analysis on the aromatic compositions indicated a close similarity between Jin Mudan and Tanyang Caicha, as well as between Meizhan and Fu’an Dabaicha. The sensory score was found significantly correlated with the volatile components in the teas.
Conclusion The 5 varieties of tea cultivars were all adequate for producing a high-quality Tanyang Gongfu black tea. However, the sensory panel’s perceptions on the teas varied due to the chemical differentiations of the leaves with which they were processed. Both content and proportion of the aromatics in the tea leaf significantly altered the characteristics of a tea product made from the leaves.
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