CHIROSPECIFIC ANALYSIS IN FLAVOR AND ESSENTIAL OIL CHEMISTRY .A. FILBERTONE - THE CHARACTER IMPACT COMPOUND OF HAZEL-NUTS

The enantiomers of (E)-5-methyl-2-hepten-4-one (filbertone) have been directly separated by capillary gas chromatography on fused silica capillaries with heptakis (2,3,6-tri-O-methyl)-beta-cyclodextrin as stationary phase. The enantiomeric composition of this compound in raw and roasted hazel-nuts of different origins was determined by this method. Additionally, the odor quality of both enantiomers of (E)-5-methyl-2-hepten-4-one and (Z)-5-methyl-2-hepten-4-one were described by sniffing synthetic (racemic) filbertone on a sniffing port at the end of a beta-cyclodextrin capillary. Besides the chromatographic separation, a filbertone sample (100-mu-g), isolated by a combination of MPLC/preparative capillary gas chromatography from roasted hazel-nuts, was investigated for its enantiomeric composition by H-1-NMR, adding the chiral shift reagent Eu(hfc)3. The taste quality of the two filbertone enantiomers was determined by a test panel using the pure (+)-(S)- and (-)-(R)-isomers isolated by preparative HPLC.