| Abstract
| - The aroma of six premium quality Spanish red wines has been studied by quantitative gaschromatography−olfactometry (GC-O) and techniques of quantitative chemical analysis. The GC-Ostudy revealed the presence of 85 aromatic notes in which 78 odorants were identified, two of which1-nonen-3-one (temptatively) and 2-acetylpyrazineare reported in wine for the first time. Forty outof the 82 quantified odorants may be present at concentrations above their odor threshold. Thecomponents with the greatest capacity to introduce differences between these wines are ethyl phenolsproduced by Brettanomyces yeasts (4-ethylphenol, 4-ethyl-2-methoxyphenol, and 4-propyl-2-methoxyphenol), 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol), (Z)-3-hexenol, thiols derived fromcysteinic precursors (4-methyl-4-mercaptopentan-2-one, 3-mercaptohexyl acetate, and 3-mercaptohexanol), some components yielded by the wood [(E)-isoeugenol, 4-allyl-2-methoxyphenol, vanillin,2-methoxyphenol (guaiacol), and (Z)-whiskylactone], and compounds related to the metabolism (2-phenylethanol, ethyl esters of isoacids, 3-methylbutyl acetate) or oxidative degradation of amino acids[phenylacetaldehyde and 4,5-dimethyl-3-hydroxy-2(5H)-furanone (sotolon)]. The correlation betweenthe olfactometric intensities and the quantitative data is, in general, satisfactory if olfactometricdifferences between the samples are high. However, GC-O fails in detecting quantitative differencesin those cases in which the olfactive intensity is very high or if odors elute in areas in which the odorchromatogram is too complex. Keywords: Wine; aroma; gas chromatography−olfactometry; quantitative analysis; GC-iontrap MS
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