Composition of Australian honey extractives .1. Norisoprenoids, monoterpenes, and other natural volatiles from blue gum (Eucalyptus leucoxylon) and yellow box (Eucalyptus melliodora) honeys

Chemical fingerprinting of Australian honey requires information on the composition of natural honey volatiles if it is to be useful as a honey-sourcing method. The naturally occurring volatiles of Australian blue gum (Eucalyptus leucoxylon) and yellow box (Eucalyptus melliodora) honeys were isolated by solvent (ethyl acetate) extraction. Compounds in the extracts were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). These procedures have permitted the identification of 55 compounds that include norisoprenoids, monoterpenes, benzene derivatives, aliphatic compounds, and Maillard reaction products. The following 13 compounds were quantitatively identified for the first time in honey: four isomeric 3,4-dihydro-3-oxoactinidols; 8,9-dehydrotheaspirone; two isomeric 3-oxoretro-α-ionols; megastigm-4-ene-3,9-dione; 1-phenylbutane-2,3-diol; 1-phenylbutane-2,3-dione; 18-hydroxyoleic acid lactone; 3,5-dihydroxy-2-methyl-4H-pyran-4-one; and 2,5-dimethyl-2,4-dihydroxy-3(2H)-furanone. The nature of the volatiles and semivolatiles in these two Australian honeys suggests that Australian honeys are quite distinctive relative to the other honeys that have been chemically studied by GC-MS.