Characterisation of volatile fraction of monovarietal wines:: Influence of winemaking practices

Twenty-three monovarietal wines from 13 white and red grapes have been analysed by solid phase extraction-gas chromatography and solid phase micro-extraction-gas chromatography. The content of some varietal terpenic and fermentative volatile compounds was determined. The 13 studied varieties were characterised as well as the influence of winemaking practices like cold soaking and addition of glycosidase enzymes. Terpenic compounds showed a high variability between the 13 varieties which allows for its characterisation. The winemaking practices devoted to increase the aromatic properties of wines produced different results depending on the variety of grape. For example, cold soaking produced very different results if applied on Palomino fino variety or on Traminer variety, whereas for Viura variety few changes were found. Regarding the volatile compounds generated during the alcoholic fermentation, its relative amount is clearly related to the kind of fermentation process carried out, and particularly according to whether maceration of the solid parts has or has not been done during the process. In the case of vinification without maceration, there is a relative increase of fatty acids and their ethyl esters, whereas in vinification with maceration, the ethyl esters of lactic, acetic and succinic acids are the compounds that are relatively more abundant. Additionally, none of these compounds was affected by the techniques applied to increase varietal aroma, i.e. cold soaking, and addition of glycosidase enzymes showed very low influence in the levels of this kind of compounds. (c) 2005 Elsevier B.V. All rights reserved.