STEREOISOMERIC FLAVOR COMPOUNDS .71. DETERMINATION OF THE ORIGIN OF AROMA-ACTIVE DIHYDROFURANONES

The odour characteristics of chiral 3[2H]-furanones, which are important aroma compounds, have been evaluated by sniffing the separated enantiomers through the port of a gas chromatograph (gc-sniffing). The results revealed great differences in the odour quality and thresholds of the single enantiomers. The determination of the origin of 2,5-dimethyl-4-hydroxy-3[2H]-furanone and 2,5-dimethyl-4-methoxy-3[2H]-furanone from strawberries, pineapples and commercial samples has been achieved using GC-isotope ratio mass spectrometry (GC-IRMS). For this technique to be successful, it is essential that preparative and storage procedures should not influence the isotope ratio of compound analysed; this is demonstrated to be the case for 2,5-dimethyl-4-hydroxy-3[2H]-furanone.