STUDIES ON THE AROMA FORMATION MECHANISM OF OOLONG TEA .3. TRANS-LINALOOL AND CIS-LINALOOL 3,6-OXIDE 6-O-BETA-D-XYLOPYRANOSYL-BETA-D-GLUCOPYRANOSIDES ISOLATED AS AROMA PRECURSORS FROM LEAVES FOR OOLONG TEA

New glycosidic aroma precursors (1 and 2) of the main volatile constituents, trans- and cis-linalool 3,6-oxides (linalool oxides I and II), were isolated from oolong tea leaves (Camellia sinensis var. sinensis cv. Maoxie). The isolation was guided by an enzymatic hydrolysis with acetone powder prepared from fresh tea leaves (cv. Yabukita) followed by GC or GC-MS analyses. Chromatographic purification of hot water extracts of the tea leaves on active charcoal, Amberlite XAD-2, and Sephadex LH-20 columns as well as HPLC gave two new glycosides, trans- and cis-linalool 3,6-oxide 6-O-beta-D-xylopyranosyl-beta-D-glucopyranosides (1 and 2).