IDENTIFICATION OF SUBSTANCES RESPONSIBLE FOR THE SAWDUST AROMA IN OAKWOOD

The unpleasant 'sawdust' odour sometimes found in wines aged in new ba rrels was studied by gas chromatography olfactory detection and mass s pectrometry. A particular aromatic zone has several chromatographic pe aks, corresponding to certain characteristic odours which can be detec ted by smelling the gas effluent. These include the subtle rancid, wee dy odour of 'sawdust'. Various carbonyl components have been identifie d in this particular zone. These include (E)-2-nonenal, 3-octen-1-one, (E)-2-octenal and I-decanal. These molecules are the primary cause of disagreeable oak wood odours. By measuring (E)-2-nonenal in wines, af ter derivation by O-(2,3,4,5-pentafluobenzyl)-hydroxilamine (PFBOA), i t was possible to correlate the concentration of this unsaturated alde hyde with the intensity of the 'sawdust' character noted in tasting. T he possible explanations for the presence of these carbonyl compounds are debatable. The carbonyl content varied from ope wood sample to ano ther. However, controling the toasting of the wood, both in the labora tory and in the cooperage, produced a major reduction in the extractab le (E)-2-nonenal content and eradicated the 'sawdust' character of the wine. (C) 1998 SCI.