ABSTRACT

The aim of this study was to characterize the volatile compounds which contribute to the aroma of Chardonnay wines. Differences of origin or winemaking method were not taken into account. First of all, 48 wines (19 of them were not Chardonnay) were characterized by their degree of typicality according to the " Chardonnay wine " concept, determined by a panel of experts. It allowed to select 18 wines belonging to two different levels of typicality: good examples and bad examples of Chardonnay wine. 
The second step of our study was undertaken to find an extraction method resulting in an extract with a good representativeness of the original wine. Three extraction methods were evaluated: solvent extraction with Cl2CH2, wine demixing followed by a vacuum distillation and wine demixing followed by a solvent extraction with Cl2CH2. The obtained extracts were diluted in an ethanol-water solution (12% volume) to be compared to the original wine by a similitude sensory test. The results did show significant differences of representativeness between methods. The methyl chloride extraction was chosen because of its good compatibility with chromatographic analysis and its easiness. 
During the third step, we selected olfactometry panelists. Four tests concerning the ability of subjects to describe odors, their repeatability in perceiving and describing odors and the presence of hyposmia, allowed us to select 17 people among 29.
Then, the olfactometric analysis was conduced on the 18 selected wines, by the method of detection frequencies. 72 odorant zones were determined and links could be showed between values of frequencies and typicality of wines, by a PLS regression. 
Nevertheless, saturated odorant zones and co-elutions were numerous, indicating an important limit of detection frequency methodologies, when olfactometric indices are used to explain differences between products. 
Finally, 101 volatile compounds associated to the 72 odorant zones were found, and 71 of them were identified. 






Keywords : aroma, Chardonnay wine, typicality, representativeness, olfactometry, mass spectrometry, PLS regression.