engleski

The influence of ochratoxin A on growth parameters and oxidative stress response in selected wine yeast

Ochratoxin A (OTA), a frequent contaminant of many foodstuffs including cereals and wine, is a mycotoxin produced as a secondary metabolite by several toxigenic molds belonging to Aspergillus and Penicillum species. The role of wine yeast in removal of this toxin from wine has been reported by different authors. The aim of the study was to examine whether and how OTA influences growth parameters of selected wine yeast strains Saccharomyces cerevisiae and Saccharomyces uvarum. Experiments were conducted using uncontaminated and toxin-containing medium and inoculated with yeast inoculum of a concentration amounting to 106 cfu/mL. The samples were analyzed periodically to assess final cell number and cell diameter during seven days at 28oC. Obtained results show that in both yeasts the differences between the final cell number in the medium with OTA and the control were not statistically significant. Ochratoxin A primary affected cell diameter reduction (up to 20%) both of S. cerevisiae and S. uvarum. Monitoring of oxidative status of yeast cells, through FOX assay and activities of superoxide dismutase, catalase and glutathione peroxidase, showed that ochratoxin A influences oxidative stress in yeast cells. Whether the changes in oxidative status are connected with impaired yeast growth is still object of study.

yeast ; wine ; ochratoxin A

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