1,8-Cineole in French Red Wines: Evidence for a Contribution Related to Its Various Origins

The aromatic descriptor green; reflecting grape unripeness in French red wines, is frequently associated with the levels of 3-alkyl-2-methoxypyrazines, particularly 3-isobutyl-2-methoxypyrazine (IBMP), which has bell pepper nuances. Nevertheless, not all green aromatic expressions in red wines correlate with 3-alky1-2-methoxypyrazine concentrations. This study considered sensory and chemical approaches using Cabernet Sauvignon wines obtained from grapes harvested at one-month intervals during the 2014 and 2015 vintages to investigate other volatile odoriferous compounds. Semipreparative HPLC fractionation of wine extracts revealed a fraction with specific green aromas in the early harvest wines. Its sensory impact was confirmed by omission and reconstitution tests. Then, multidimensional gas chromatography coupled with olfactometry and mass spectrometry (MDGC-O-MS/TOF) was used for molecular characterization of the aroma compounds associated with the green aromas. Surprisingly, eucalyptol (1,8-cineole), with menthol odor was highlighted and assayed at concentrations sometimes above its olfactory detection threshold in Cabernet Sauvignon and Fer Seryadou wines. Sensory tests confirmed its impact at several, concentrations detected in French red wines (up to 461 +/- 0.03 mu g/L) on the menthol nuance and overall green perception, particularly via an additive effect with IBMP. Quantitation of 1,8-cineole in Cabernet Sauvignon and Merlot grapes during berry development in 2015 revealed its varietal origin with abundant concentrations in unripe berries and decrease during grape maturation. Moreover, the implication of an invasive plant (Artemisia verlotiorum) growing in certain vineyards was shown to be responsible for increased 1,8-eineole concentrations in some wines.