Comparative Study of the Aroma Components of Several Oolong Teas
Oolong teas are mainly produced in the south and north of Fujian, Guangdong and Taiwan, and they have unique aroma qualities in different producing districts. The sensory evaluation and HS-SPME/GC-MS were applied to analyze the aroma qualities and aroma components of typical Oolong teas from the four producing districts in this study. The results showed that, the main aroma components include alcohol, ketone, aldehyde, ester, hydrocarbon, phenols and nitrogenous compounds. However, the aroma components of the Oolong teas from different districts showed large differences. Trans-nerolidol (40.96%) and α-farnesene (20.00%) were found as the major aroma components of high-mountain Oolong tea from Taiwan. While trans-nerolidol (46.22%), indole (15.20%) andα-farnesene (23.01%) were found as the major aroma components of fresh scent-flavor Tieguanyin from south of Fujian province. Linalool and its oxidates (11.87%), ionones (5.26%) and 3-hexenyl ester, (z)-hexanoic acid (5.05%) were the major aroma components of Shuixian from north of Fujian province, and trans-nerolidol (31.43%) and indole (35.83%) were found as the major aroma components of Wuye dancong from Guangdong province. The aroma components of different fermentation-degree Oolong teas, including Jinxuan Oolong tea and Oriental beauty tea were analyzed and compared. The correlations between the aroma quality and aroma components were also discussed.