Botrytized wines yeasts

Sipiczki, M. (2003). Candida zemplinina sp. nov., an osmotolerant and psychrotolerant yeast that ferments sweet botrytized wines. Int. J. Syst. Evol. Microbiol. 53, 2079-2083. 

These results suggest that non-Saccharomyces species may contribute significantly to the fermentation of botrytized wines. C. zemplinina seems not to produce excess volatile compounds nor any specific aroma compounds (Toth-Markus et al., 2002). Its main contribution to the chemical composition might be an increase in glycerol content and in the G F ratio. C. zemplinina and C. stellata have proven to be very fructo-philic yeasts (Mills et al., 2002 Magyar and Toth, 2011 Magyar et al., 2008). 

The use of selected yeast starters for botrytized wine fermentation is strongly encouraged in Germany (Dittrich, 1977 Hoersch and Schlotter, 1990), in Sauternes (Dubourdieu, 1999 Ribereau-Gayon et ah, 2000), and is typical in the newer botrytized wines produced in Australia, and South... 

Cessation of fermentation is one of the technical problems in botrytized wine production that needs further research and development. Dimethyldicarbonate (DMDC) is now considered a reliable inhibitor which could replace some of the S02. Although DMDC has proven suited for treating wines especially just before bottling, its use in Sautemes production has been investigated (Divol et al., 2005). The results showed that DMDC at a rate of 100-200 mg/1 stopped fermentation but did not replace the antioxidant functions of SO2. Sulfite addition was necessary to limit wine oxidation and yeast reactivation. 

Banszky, L., Ujhelyi, G., Pomazi, A., and Maraz, A. (2003). Population dynamics of Candida stellata during botrytized wine fermentation. Book of Abstracts of the 23rd International Specialised Symposium on Yeasts, Budapest, Hungary, Diamond-Congress Ltd, Budapest, p. 89, Book of Abstracts. 

Botrytis Effect on Fermentation. Peynaud et al. (28) suggest that Botrytis cinerea ( noble rot ) produces a substance that inhibits yeast activity. While this substance has not been isolated in the United States, it has been the author s observation that botrytis-infected grapes ferment at a slower rate and have more difficulty completing fermentation. This fermentation inhibition also may be attributable to the higher initial °Brix and, later, to the ethanol and higher residual sugar content of the botrytized wines. 

The artificial induction of noble rot would greatly facilitate making botrytized sweet wine, extending their production to countries where conditions are unfavorable for the natural development of noble rot. Experiments have long been performed to this end. In the earliest work, Nelson and Amerine (1956) unsuccessfully tried to induce its development in the vineyard by inoculation. The necessary moisture condition after inoculation was impossible to reproduce under field conditions. In addition, the method creates the risk that other fungi (Penicillium, Aspergillus, Rhizopus), yeasts and, acetic acid bacteria could develop if unfavorable weather conditions arose (Dittrich, 1977). 

FIGURE 6.4 Course of alcoholic fermentation and evolution of the yeast populations during spontaneous fermentation of Tokaji Aszu. Botrytized berries were macerated with fermenting must (A) or dry wine (B) (Magyar, 2010). 

Antunovics, Z., Csoma, H., and Sipiczki, M. (2003). Molecular and genetic analysis of the yeast flora of botrytized Tokaj wines. Bull. OIV 76, 380-397. 

Bene, Zs. and Magyar, I. (2004). Characterization of yeast and mould biota of botrytized grapes in Tokaj wine region in the years 2000 and 2001. Acta Aliment. Hung. 33, 259-267. 

The yeast strain used for fermentation had no impact on the enantiomer distribution of these volatile thiols. 3SHA is generally considered to be formed by esterification of 3SH by yeast during alcoholic fermentation. The esterase or lipase involved probably acetylates 3SH with a certain enantioselectivity. In contrast, the enantiomer distribution of 3SH in wine made from botrytized grapes (Botrytis cinerea) is 25 75 in favor of the S form, which has also been found in botrytized must (Thibon et al. 2007,2008a). 

The most abundant SO2 combination due to Gluconobacter results in 5-oxofhictose, which is not metabolized by yeast, so it remains unchanged in Ihe wine. It is formed by oxidation of any fructose in the medium, as is the case in grape must. In a botrytized must where the fungus has developed to its most advanced stage, Ihis compound alone... 

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