Analysis of Characteristic Aroma Components of Sichuan Dark Tea

The volatile aroma compounds of 15 representative dark tea products in Sichuan Province were analyzed by sensory evaluation and headspace solid phase micro-extraction (HS-SPME) combined with gas chromato graphy-mass spectrometry (GC-MS) in this study. The results showed that ''stale flavor'' were the main aromatic aroma type of Sichuan dark tea, other tea samples had glutinous rice aroma, sweet , sour gas and smoky, which were typical of dark tea. A total of 121 aroma components were detected in the dark teas,and the major aroma compounds were alkenes (5.41%~42.38%), aldehydes (7.26%~19.97%), ketones (6.68%~39.26%) and alcohols (14.03%~27.06%). 7 principal components were extracted from the 32 common aroma components byprincipal component analysis（principal component analysis, PCA） and the total contribution attained 84.27%. Characteristic aroma components included β-ionone, 1-octen-3-ol, 2,3-dihydro-2,2,6-trimethyl,5,6-epoxy-β-ionone, geranylacetone, 3,5-octadienone (E,E), trans-2-octenal, 2-n-pentylfuran, which played important roles in the aromatic characteristics of strong and pure ''stale flavor'' of Sichuan dark tea. Relative odor activity value (ROAV) was used to evaluate the contribution of aroma components to flavor characteristics of Sichuan dark tea. It was found that the ROAV values of (E,E)-2, 4-heptadienal, linalool, geraniyl acetone, α-ionone and 1-octene-3-ol were greater than 1. The above components made great contributions to the formation of aroma characteristics of Sichuan dark tea. This study could provide a theoretical reference for research on characteristic aroma formation and quality evaluation of Sichuan dark tea.