Discrimination of Green, Oolong, and Black Teas by GC-MS Analysis of Characteristic Volatile Flavor Compounds
- 1 Leibniz-Institute of Vegetables and Ornamental Crops Gro?beeren/Erfurt e.V, Gro?beeren, Germany
- 2 South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- 3 Shizuoka Prefectural Research Institute of Agriculture and Forestry Tea Research Center, Shizuoka, Japan
- 4 Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
- 5 Graduate School of Engineering, Shizuoka University, Hamamatsu, Japan
- 6 Shizuoka Prefectural Research Institute of Agriculture and Forestry Tea Research Center, Shizuoka, Japan
- 7 Faculty of Agriculture, Shizuoka University, Shizuoka, Japan
Abstract
Tea is one of the most consumed beverages in the world and its quality is influenced by geographical origin and production methods. This study focuses on the volatile aroma components of 38 tea products from China, Japan, Indonesia, Sri-Lanka, and Chinese Taipei; among them 7 green teas, 13 oolong teas, and 18 black teas. The volatiles were extracted from the infusions using PorapakQ-resin, concentrated, and analyzed by gas chromatography-mass spectrometry. The components were identified by authentic reference compounds or preliminary based on their mass spectra. Different manufacturing processes yield different blends of aroma compounds. In general, the contents of total volatiles, aliphatics, aromatics, and terpenoids increased with the fermentation degree, whereas jasmine lactone and indole were the highest in oolong teas. Some particular manufacturing processes, for example, the use of tea leaves infested by the tea green leafhopper, lead to higher contents of volatiles in final products as in Oriental Beauty oolong tea. The relative peak areas determined for 82 volatiles were the basis for the statistical analysis and highlight the potential of multivariate analysis to distinguish tea samples of different categories.
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