Abstract: The volatile compounds of different grades of Lu Mountain Clouds-Mist Tea from three regions (Tongyuan township, Saiyang township, and Xingzi county) were investigated by solid phase micro extraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). A total of 76 of volatile components were identified. Principal component analysis was applied to find out the main factors affecting the volatile components in different grades of Lu Mountain Clouds-Mist Tea. The results showed that the first 4, 3 and 3 principal components contributed cumulatively to 80.4%, 87.9% and 89.8% of the total variation for the teas from Tongyuan, Saiyang and Xingzi, respectively. Different grades of tea could be discriminated by their respective chemical properties. The volatile compounds with variable importance in the projection (VIP) value greater than 1 in the loading plots were screened for the characteristic aroma compounds in different grades of tea. The results showed that the higher grade and more expensive Lu Mountain Clouds-Mist tea had higher contents of aroma compounds, such as hexanal, (Z)-3-hexen-1-ol, hexanol, heptanal, benzaldehyde, 2-pentyl-furan, limonene, isophorone, linalool, and jasmone. This study provides a new idea for grade discrimination of Lu Mountain Clouds-Mist Tea.

Key words: Lu Mountain Clouds-Mist tea, gas chromatography-mass spectrometry (GC-MS), volatile compounds, principal components analysis, grade discrimination