Differences in Aroma of Chuanhong Congou Black Tea of Different Tea Plant Varieties Based on HS-SPME-GC-MS Analysis

Chuanhong congou black tea was made from seven tea plant species that were grown in Yibin, including 'Sichuan Medium and Small Leaf Group Species' 'Fuding Dabai' 'Fuyun 6' 'Mingshan 131' 'Qingxin Oolong' 'Tianfu 5' and 'Tianfu 6'. The main differentiating ingredients in Chuanhong congou black tea, which was produced from the fresh leaves of several tea plant species, were examined using sensory evaluation, electronic nose (E-nose), headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV), and partial least squares discriminant analysis (PLS-DA). The findings indicated that the black tea derived from the fresh leaves of the seven different tea kinds was sweet, with the 'Sichuan Medium and Small Leaf Group Species' scoring the highest and having a little fruity flavor. A total of 84 volatile aroma compounds, including 29 alcohols, 12 aldehydes, 15 esters, 12 alkenes, 7 acids, 5 ketones and 4 other hydrocarbons were found. There were 14 kinds of common aroma compounds in the 7 samples, and the contents of aroma compounds were significantly different among different samples (P<0.05). A total of 28 kinds of main aromatic compounds of Chuanhong cougou black tea were screened (OAV>1). Eight key differential aroma compounds were identified in the black tea samples of different tea plant varieties, including geraniol, linalool, methyl salicylate, phenylethanol, styrene, 2-hexenal, (E)-linalool oxide (furan-type) and citral. In summary, the types and contents of aroma substances of Chuanhong cougou black tea made from fresh leaves of different tea plant varieties differ greatly. The study results can provide reference for selecting suitable tea plant varieties for Chuanhong cougou black tea.