GLYCOSIDE PRECURSOR OF TEA AROMA .2. AGLYCONE CONSTITUENTS IN FRESH TEA LEAVES CULTIVATED FOR GREEN AND BLACK TEA

The glycoside fractions of a methanol extract from fresh tea leaves of Camellia sinensis var. assamica clone DT-1 (DT-1) and of C. sinensis var. sinensis cv. Yabukita (Yabukita) were obtained by Amberlite XAD-2 adsorption and methanol elution, respectively. These fractions were incubated with each of four enzymes, alpha-glucosidase, beta-glucosidase, glycosidase and acetone powder (AP), at 37 degrees C for 24 h. After enzymatic hydrolysis by beta-glucosidase, the formation of (Z)-3-hexenol and benzyl alcohol was observed by GC. (Z)-3-Hexenol, linalool, linalool oxides, methyl salicylate, geraniol benzyl alcohol and 2-phenylethanol were observed after hydrolysis by the glycosidase and by acetone powder. A comparison of the calculated terpene index (TI) of the aglycones between the two varieties indicated the TI value for Yabukita to be lower and that for DT-1 to be as high as that of black tea manufactured from DT-1.