There is evidence in the literature that non-volatile wine matrix can modify the release and therefore the perception of the compounds involved in wine aroma [1-3]. The aim of the present study is to make an estimation of the nature of these changes by using a standard volatile composition added to different real wine matrices and then analyze the headspace above them.The analytical methodology is based on a previously developed DHS-TD-GC-MS method . This analytical method provides a snapshot of the contents in wine vapors and allows a better understanding of the headspace profile changes. To study the influence of the wine matrix on the release of volatile compounds, the non-volatile matrix from six different wines was isolated and all volatile compounds removed. The non-volatile matrices were used to reconstitute the six original wines but this time the volatile composition was a standard aroma solution (15 volatile compounds of different chemical families) and the same alcoholic content. The headspaces of the reconstituted wines and a model wine (12% vol. ethanol, pH 3.5) were analyzed and compared at two different moments: just after wine pouring (t=0 min) and after 10 min with glass shaking (t=10 min). The analyses were triplicated for each model wine. Also, free and total sulfur dioxide, total polyphenol index, total acidity, pH, dry mass and contents on copper, iron and zinc were determined for each wine matrix.The data collected was studied according to the time spent after wine pouring, as this factor substantially modifies the headspace of most volatile compounds. The results of a one-way ANOVA to assess the influence of the wine matrix on the initial headspace composition showed significant differences for all compounds except ethyl decanoate. Dimethyl sulfide presented marked differences among wines matrices and a significant linear anti-correlation with the copper content of the matrices. Esters showed a similar trend in the release across wine matrices, although one wine was consistently releasing lower contents of ethyl esters. Butyric and hexanoic acids were the compounds with more marked differences in release, although other compounds like β-damascenone also displayed significant differences according to the wine matrix. The variation on the release of more polar and heavier compounds, like linalool, 4-ethylphenol or vanillin in the studied matrices was more similar to that of the model wine. Only in the matrix of a young red wine a salting-out effect was detected. The data obtained in this work proves that the same volatile composition in the liquid phase of very dissimilar non-volatile wine matrices produces a headspace profile above the wines that can be significantly different and, therefore, can undoubtedly influence the perception of wine aroma.
Authors: Lopez Ricardo1, Wen Yan1 and Ferreira Vicente1
1Laboratory for Aroma Analysis and Enology, Instituto Agroalimentario de Aragón (IA2), Department of Analytical Chemistry, Faculty of Sciences, Universidad de Zaragoza
*corresponding author: firstname.lastname@example.org
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Keywords: headspace, aroma release, flavor-matrix interactions, wine, GC-MS