Aroma-active compounds of American, French, Hungarian and Russian oak woods, studied by GC-MS and GC-O

Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used to study aroma-active compounds in extracts of American, French, Hungarian and Russian oak woods. Compounds that presented high odour intensities for the non-toasted oak woods were guaiacol, hexanal, trans-2-nonenal, trans-oak lactone, cis-oak lactone, eugenol, vanillin and trans-isoeugenol, whilst the same compounds, in addition to furfural, 4-methylguaiacol and cis-isoeugenol, proved important in the toasted oaks. Like the oak lactones, cis- and trans-isoeugenol presented woody/oak odours, particularly in the toasted samples. For Hungarian and Russian samples, both characterized by their lower content of oak lactones, trans- and cis-isoeugenol presented higher odour intensities. For this reason, samples of low oak lactone concentrations, such as Hungarian and Russian oak woods, but also containing isoeugenols, can impart woody/oak odours to wines. Copyright (C) 2008 John Wiley & Sons, Ltd.