Identification and Quantification of Impact Odorants of Aged Red Wines from Rioja. GC−Olfactometry, Quantitative GC-MS, and Odor Evaluation of HPLC Fractions

TLDR

The study extracted aroma compounds from a 5‑year‑old Rioja wine using XAD‑4, analyzed them by GC‑O and GC‑MS, fractionated the extract by HPLC on a C‑18 column, and performed reconstitution experiments to confirm odorant contributions. The analysis identified 58 odorants (52 confirmed), including the first report of methyl benzoate in Rioja wine, with key contributors such as 4‑ethylguaiacol, (E)-whiskey lactone, 4‑ethylphenol, β‑damascenone, fusel alcohols, isovaleric and hexanoic acids, eugenol, fatty acid ethyl esters, ethyl esters of isoacids, Furaneol, phenylacetic acid, and (E)-2‑hexenal, and demonstrated that GC‑O, GC‑MS, and HPLC fractionation are complementary. Keywords: gas chromatography–olfactometry, aroma extract dilution analysis, odor activity value, HPLC fractionation, red wine, aroma, flavor.

Abstract

An XAD-4 extract from a 5-year-old wine from Rioja (Spain) was analyzed by aroma extract dilution analysis. Most of the odorants were quantified by GC-MS. A second extract was fractionated in an HPLC system with a C-18 semipreparative column. Fifty fractions were recovered, their alcoholic degree and pH were further adjusted to those of the wine, and those fractions that showed strong odor characteristics were further re-extracted and analyzed by GC-O and GC-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 was found to be a wine aroma constituent for the first time. The most important odorants are 4-ethylguaiacol, (E)-whiskey lactone, 4-ethylphenol, β-damascenone, fusel alcohols, isovaleric and hexanoic acids, eugenol, fatty acid ethyl esters, and ethyl esters of isoacids, Furaneol, phenylacetic acid, and (E)-2-hexenal. Comparison among the three techniques shows good agreement and demonstrates that they are complementary. Keywords: Gas chromatography−olfactometry; aroma extract dilution analysis (AEDA); odor activity value (OAV); HPLC fractionation; red wine; aroma; flavor