Influence of tebuconazole residues on the aroma composition of Mencía red wines

Tebuconazole is a triazole fungicide used in the treatment of diseases of vinification grapes. In this work, Mencía red grapes harvested in Valdeorras (Ourense, NW Spain) were used in three vinification experiments performed in an experimental cellar. Experiment A was conducted on uncontaminated crushed, destemmed grapes and involved inoculation with commercially available yeasts at the beginning of alcoholic fermentation. In experiments B and C, crushed, destemmed grapes were spiked with a pure standard of tebuconazole and inoculated with commercial yeasts (experiment B) or endogenous yeasts (experiment C). The main volatile compounds responsible for the aroma composition of the resulting wines were determined in order to evaluate the influence of tebuconazole residues on the outcome of the winemaking process. Terpene and higher-alcohol concentrations were essentially similar in the three wines; by contrast, C6-alcohol, ester and aldehyde concentrations differed significantly between them.