Nuevas aportaciones al conocimiento y utilización de productos fitosanitarios para el control de enfermedades de la vidEvaluación de posibles efectos sobre la fermentación y elaboración de vinos de calidad

Abstract

Stuck fermentations in red wine vinification involve serious problems in Denominación de Origen Calificada Rioja as shown by the continuous disqualifications of wines, according to the data of the Control Board. A factor involved in this problem is the presence of pesticide residues in harvested grapes and, therefore, in fermenting must. The first objective of this work was the development of analytical methods for the determination of four fungicides: dichlofluanid, metalaxyl, pyrimethanil and penconazol and grapes, must and wine. Then, the influence of pyrimethanil application (widely used in DOCa Rioja) on grapes, fermentation, and sensory and enological characteristics of obtained wines was studied. Furthermore, the effect of growth regulator prohexadione calcium application in Tempranillo grapevines was studied. This research was innovative and original in Spain and the European Union. The results have shown that the application of the fungicide pyrimethanil did not systematically affect the enological parameters. It did not modify the evolution of alcoholic and malolactic fermentations, or the organoleptic characteristics of wine. Pyrimethanil concentration found in grapes was always lower than the Maximum Residue Limits established by legislation. The amount decreased during the winemaking process. The application of prohexadione calcium at preblooming led to a reduction in crop yield and berry size, increasing the concentration of compounds responsible for the color, aroma and flavor of wines. Fermentative processes (alcoholic and malolactic fermentations) were not affected. The treatment favourably modified the sensory characteristics of wines obtained from treated grapevines.