Influence of new generation fungicides on Saccharomyces cerevisiae growth, grape must fermentation and aroma biosynthesis

The influence of ten new generation fungicides (ametoctradin, benthiavalicarb-isopropyl, boscalid, cyazofamid, dimethomorph, fenhexamid, kresoxim-methyl, mepanipyrim, metrafenone, and pyraclostrobin) on the fermentative activity of Saccharomyces cerevisiae yeast was initially evaluated in pasteurised red must. The presence of ametoctradin, dimethomorph and mepanipyrim seemed to affect sugars-to-ethanol yield in the stationary phase. The same fermentation experiments were carried out for these three fungicides in ecological red must from Vitis vinifera cv. Tempranillo. When ecological must was unfiltered, the fermentative activity of yeasts was unaffected by the presence of these selected fungicides. However, when ecological must was filtered beforehand, a slight decrease of biomass and ethanol production (in terms of biomass-to-ethanol yield and sugars-to-ethanol yield, respectively), as well as a decrease in fruity aroma, were registered with respect to the control wine.