Identification of character impact odorants of different white wine varieties

Application of gas chromatography/olfactometry (GC/O) to the analysis of extracts of Scheurebe and Gewurztraminer wines yielded 36 and 40 odor-active compounds, respectively, Ethyl 2-methylbutyrate, ethyl isobutyrate, 2-phenylethanol, 8-methylbutanol, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 3-ethylphenol, and an unknown compound named wine lactone showed high flavor dilution factors in both varieties. Wine lactone was identified as 3a,4,5,7a-tetrahydro-3,6-dimethylbenzofuran-2(3H)-one and was detected for the first time among the volatiles of wine or a food. The compound exhibited an intense coconut, woody, and sweet odor. 4-Mercapto-4-methylpentan-2-one belongs to the most potent odorants only in the variety Scheurebe, whereas cis-rose oxide was a key substance for the overall flavor of Gewurztraminer wine. GC/O of static headspace samples of both wine varieties revealed butane-2,3-dione, dimethyl sulfide, and dimethyl trisulfide as further potent odorants.