8A Wine Aroma Precursors 265
However, the PDMS levels of the young wines were always lower than those
of the corresponding musts, and no clear relationship was found between them.
The simple chemical degradation of SMM could hardly explain the high losses
observed in some samples from must to wine, which could be due to must enzy-
matic activities, or to the microorganisms of the fermentation steps. Indeed, the
degradation of SMM by enzymes of the metabolism of sulfur compounds or ethy-
lene, such as SMM-homocysteineS-methyltransferase orS-methyl-L-methionine
hydrolase or 1-aminocyclopropane-1-carboxylate synthase (ACC synthase), were
previously reported in higher plants (Kiddle et al. 1999; Ko et al. 2004). Further-
more, although SMM fate inSaccharomyces cerevisiaeyeast has not been studied,
a SMM-homocysteineS-methyltransferase activity was evidenced in yeast lysates
(Shapiro et al. 1964) and a recent work showed that SMM is transported in the
yeast cells by two permeases (Rouillon et al. 1999). Thus, the partial degradation of
SMM by some yeast strains seems conclusive, as this work brought evidence that
yeast is able to use SMM as an efficient sulfur source, which explain PDMS levels in
young wines differing from those in the corresponding musts. It must be noted that
a long time ago, Schreier et al. (1976) hypothesized that DMS could be generated
by yeast from SMM during fermentation, as it was shown during cheese ripening
(Spinnler et al. 2001). Anyway, DMS produced from SMM during the first steps
of winemaking should be mainly stripped off by CO2 during yeast fermentation, as
mentioned above for DMS produced from other sulfur sources. Thus, the knowledge
of the factors governing the recovery of SMM from grape and its degradation during
the fermentation step, should allow its levels to be controlled in wine at bottling, and
therefore, the levels of DMS generated in bottled wine during aging.
References
Albagnac, G. (1975). La d ́ecarboxylation des acides cinnamiques substitu ́es par les levures.Ann.
Technol. Agric., 24, 133–141.
Anness, B. J., & Bamforth, C. W. (1982). Dimethyl sulphide – a review.J. Inst.Brew., 88, 244–252.
Anocibar Beloqui, A. (1998). Les compos ́es soufr ́es volatils des vins rouges.Doctoral dissertation,
University Victor Segalen Bordeaux II.
Anocibar Beloqui, A., Kotseridis, Y., & Bertrand, A. (1996). D ́etermination de la teneur en sul-
phure de dim ́ethyle dans quelques vins rouges.J. Int. Sci. Vigne Vin, 30, 167–170.
Bailly, S., Jerkovic, V., Marchand-Bryaert, J., &Collin, S. (2006). Aroma extraction dilution analy-
sis of Sauternes wines. Key role of polyfunctional thiols.J. Agric. Food Chem., 54, 7227–7234.
Bamforth, C. W., & Anness, B. J. (1981). The role of dimethyl sulphoxide reductase in the forma-
tion of dimethyl sulphide during fermentation.J. Inst.Brew., 87, 30–34.
Baumes, R., Bayonove, C., Cordonnier, R., Torres, P., & Seguin, A. (1989). Incidence de la
mac ́eration pelliculaire sur la composante aromatique des vins doux naturels de muscat.Rev.
Fr. Oenol., 116, 5–11.
Baumes, R., Aubert, C., G ̈unata, Z., De Moor, W., & Bayonove, C. (1994). Structure of two C13
norisoprenoid glucosidic precursors of wine flavor.J. Essent. Oil. Res., 6, 587–599.
Baumes, R., Wirth, J., Bureau, S., G ̈unata, Z., & Razungles, A. (2002). Biogeneration of
C 13 −norisoprenoid compounds: Experiments supportive for an apo-carotenoid pathway in
grapevines.Anal. Chim. Acta, 458, 3–14.