IMPROVING THE COLOUR OF ‘TEMPRANILLO’ GRAPES BY SPRAYING ETHANOL AT VERAISON AND PRE-HARVEST

Different studies have shown that spraying hydroalcoholic solutions on the grapes during ripening promotes the synthesis of ethylene and thereby enhances its content in polyphenols at harvest; although their effects depend on cultivar, dose and timing of application.
The aim of this work was to evaluate the effects of different ethanol treatments over the chromatic characteristics of ‘Tempranillo’ grapes.
In an experiment conducted in ‘Ribera del Duero’ Denomination of Origin (Spain) during 2007 and 2008, three different doses (0, 5 and 10% v/v) of ethanol hydroalcoholic solutions were applied over the clusters at two different times: at the end of veraison and twelve days before harvest.
Treatment dose of 5% increased berry weight over the controls at both times of application.
Spraying ethanol did not produce significant changes in the composition of the berries; however, applications at veraison (both doses) increased significantly the hue of musts.
Also grapes treated at veraison showed a higher colour fraction associated to polymeric pigments than non-treated grapes.
Because of that ethanol spraying could contribute to improve colour stability in wines.

XI International Symposium on Plant Bioregulators in Fruit Production

R. González, M.R. González, L. Uzquiza, P. Martín

ethylene, polyphenols, polymeric pigments, Vitis vinifera

https://doi.org/10.17660/ActaHortic.2010.884.63