Morphological and taxonomic study on mycobiota of noble rotted grapes in the Tokaj wine district

Noble rot of the grape is a complex microbiological-biochemical process having grate importance in the Tokaj wine district. In this study, morphology and development of Botrytis cinerea in the berry skin as well as the presence of other moulds and yeasts on the digested exocarp of the noble rotted grapes (aszú) were investigated and presented by scanning electron microscopy. Another aim of this work was a comprehensive taxonomical characterisation of the yeasts present on the surface of the “aszú” berries in the Tokaj wine district in five vintage years. The dominant yeasts were isolated and taxonomically identified according to phenotypical properties. The most prevalent yeast species of the aszú grapes were Metschnikowia pulcherrima in the vineyard and Candida stellata in the winery (the latter species has been recently differentiated for two species, C. stellata and C. zemplinina). These two Candida species seem to be typical yeasts of Tokaj aszú berries, particularly after picking, transporting and storage of the aszú grape. These postharvest operations significantly influence mould and yeast populations of botrytized grapes