Identification and quantification of impact odorants of aged red wines from Rioja. GC-olfactometry, quantitative GC-MS, and odor evaluation of HPLC fractions

An XAD-4 extract from a 6-year-old wine from Rioja (Spain) was analyzed by aroma extract dilution analysis. Most of the odorants were quantified by CC -MS. A second extract was fractionated in an HPLC system with a C-18 semipr eparative column. Fifty fractions were recovered, their alcoholic degree an d pH were further adjusted to those of the wine, and those fractions that s howed strong odor characteristics were further re-extracted and analyzed by GC-O and CC-MS. Reconstitution experiments were carried out to confirm the role of the odorants detected in the fractions. Fifty-eight odorants were found in the Rioja wine, 52 of which could be identified. Methyl benzoate w as found to be a wine aroma constituent for the first time. The most import ant odorants are 4-ethylguaiacol, (E)-whiskey lactone, 4-ethylphenol, beta -damascenone, fusel alcohols, isovaleric and hexanoic acids, eugenol, fatty acid ethyl esters, and ethyl esters of isoacids, Furaneol, phenylacetic ac id, and (E)-2-hexenal. Comparison among the three techniques shows good agr eement and demonstrates that they are complementary.