OPTICAL ISOMERS OF LINALOOL AND LINALOOL OXIDES IN TEA AROMA

The main aroma components of oolong and black tea, linalool and four diastereomers of linalool oxides (LOs), were enantioselectively isolated by capillary gas chromatography, using a column coated with an optically active liquid phase, permethylated beta-cyclodextrin. The R/S ratio varied among linalool and LOs, and among the different types of tea, the ratio for a particular compound also being different. However, the complete patterns of R/S ratio were similar in the semi-fermented and fermented teas, respectively. Using a specific cultivar of black tea, the R/S ratio for each of the five compounds was compared in the free state in black tea with that of an aglycone of the glycoside in fresh tea leaves or in black tea. While the e.e. values of the compounds varied, those for a specific compound were similar, except for linalool, regardless of their free or combined state. These results show that LOs are not directly transformed from linalool, but are formed enzymatically from glycoside precursors.