Acetoxy-1,8-cineoles as aroma constituents of Alpinia galanga Willd.

Four isomers of acetoxycineoles, (trans and cis)-2- and 3-acetoxy-1,8-cineo les, were identified as the odorous components of the rhizomes of greater g alangal. Their structures were confirmed by comparing the retention indices by GC and the mass spectra with those of synthesized compounds. The concen tration of trans-3-acetoxy-1,8-cineole was the highest among the isomers. T he isomers presented individual odor features: the (trans and cis)-2 isomer s respectively exhibited woody and sweet aromas, while the (trans and cis)- 3 isomers respectively showed sweet floral and camphoraceous aromas. Of the se, trans-2-acetoxy-1,8-cineole seemed to have the strongest qualitative ef fect on the characteristic flavor of greater galangal.