Objective Differences in aroma and chemistry of the Gongfu black teas made of leaves of different cultivars in Zhejiang Province were analyzed.

Method Aromatics in the Gongfu black teas made of leaves plucked from 11 different tree varieties were determined using the headspace stir bar adsorption thermal desorption gas chromatography-mass spectrometry. The relative odor activity value (ROAV) of the compounds and sensory panel evaluation on the brewed teas were compared. Cluster analysis and OPLS-DA on the relative contents of major aromatics in the teas were performed to identify differentiate compounds according to VIP value.

Result Forty volatile substances were found in the 11 black tea specimens that represented the floral, sweet-and-fruity, and fresh-sweet or fresh-sweet-and-floral types of aroma. Alcohols, esters, aldehydes, alkenes, and ketones were the predominant chemicals that contributed to the tea aroma, with alcohols being the highest in quantity. Based on ROAV, β-linalool, decanal, geraniol, oxidized linalool II (furan type), oxidized linalool I (furan type), and methyl salicylate were the 6 major aromatics commonly found in the teas. The teas, Chunyu 2, Zhonghuang 2, Jinmudan, and Jinguanyin delivered the typical floral fragrance from the high content of linalool and its oxides. Meizhan, Jiukengzhong, Jiukengzao, and Shaobai 1 were high on β-laurene, geraniol, 1-octen-3-ol, methyl salicylate, orange blossom alcohol, trans limonene, and 2-n-pentyl furan, which characterized the mild rose fragrance, light fatty note, green grass smell, and holly oil scent that typified the fresh, sweet, and floral aroma type. Meanwhile, the sweet-and-fruity Yujinxiang, Huangguanyin, and Fudingdabai distinctively contained β-cyclic citral and trans-2-hexenal.

Conclusion The aroma of the 11 Gongfu black teas produced in Zhejiang was categorized as floral, sweet-and-fruity, and fresh-sweet or fresh-sweet-and-floral types. The main compounds that differentiated the sensory quality of the teas included 1-hexyl-2-formylpyrrole, 2-pentylfuran, 6-methyl-5-hepten-2-one, β-cyclocitral, (E)-2-hexenal, (E)-nerolidol, (E,E)-3,5-octadien-2-one, 1-nonanol, hexyl hexanoate, limonene, hexanal, linalool oxide I (furanoid), dehydrolinalool, phenylethyl alcohol, benzyl alcohol, benzaldehyde, and 1-octanol.