Acetoxy-1,8-cineoles as Aroma Constituents of Alpinia galanga Willd.

Four isomers of acetoxycineoles, ( trans and cis )-2- and 3-acetoxy-1,8-cineoles, were identified as the odorous components of the rhizomes of greater galangal. Their structures were confirmed by comparing the retention indices by GC and the mass spectra with those of synthesized compounds. The concentration of trans -3-acetoxy-1,8-cineole was the highest among the isomers. The isomers presented individual odor features: the ( trans and cis )-2 isomers respectively exhibited woody and sweet aromas, while the ( trans and cis )-3 isomers respectively showed sweet floral and camphoraceous aromas. Of these, trans -2-acetoxy-1,8-cineole seemed to have the strongest qualitative effect on the characteristic flavor of greater galangal. Keywords: Alpinia galanga Willd.; greater galangal; rhizome; flavor component; trans-2-acetoxy-1,8-cineole; cis-2-acetoxy-1,8-cineole; trans-3-acetoxy-1,8-cineole; cis-3-acetoxy-1,8-cineole