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Advisor(s)
Abstract(s)
Quinones are electrophilic species which can react with various nucleophiles, like wine antioxidants, such as sulfur dioxide or ascorbic acid, thiols, amino acids, and numerous polyphenols. These reactions are very important in wine aging because they mediate oxygen reactions during both production and bottle aging phases. In this work, the major challenge was to determine the interaction between ortho-quinones and wine nucleophiles (amino acids, thiols, and the antioxidants SO2 and ascorbic acid), by cyclic voltammetry. Wine-model solutions with gallic acid, caffeic acid, or (+)-catechin and nucleophilic compounds were used. To understand the effect of nucleophilic addition in wine, a white wine with the same added nucleophiles was also analysed. Cyclic voltammograms were taken with glassy carbon electrode or screen-printed carbon electrodes, respectively, for wine-model and white wines solutions, in the absence and in the presence of nucleophiles. A nucleophilic order profile related to the cathodic current intensity decrease was observed.
Description
Keywords
Oxidation Quinones Thiols Amino acids Antioxidants Wine Cyclic voltammetry Phenolics
Pedagogical Context
Citation
OLIVEIRA, Carla. M.; BARROS, António S.; FERREIRA, António César Silva; SILVA, Artur M. S. - Study of quinones reactions with wine nucleophiles by cyclic voltammetry. Food Chemistry. ISSN 0308-8146. Vol. 211 (2016), p. 1-7
Publisher
Elsevier