Effects of noble rot on the grape microbiota

Using direct isolation, without enrichment, Saccharomyces species were not found on Tokaj aszu berries (Csoma, 2008 Magyar, 2006 Magyar and Bene, 2006), although Naumov et al. (2002) reported the presence of S. uvarum and S. cerevisiae on Tokaj grapes (method of isolation unknown). During spontaneous fermentations, however, diverse Saccharomyces populations can be detected in botrytized musts (see Section IV.C). 

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). 

Several attempts were made to inoculate Botrytis spores or enzymes directly into juice or must (King et al., 1969 Watanabe and Shimazu, 1976). Field inoculation, however, is closer to the natural noble-rot process and is likely to be more acceptable to consumers. Thus, vineyard experiments are continuing. 

In experiments conducted in Burgenland, Austria, it was found that artificial inoculation of ripening berries with a Botrytis spore suspension 

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