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Influence of light exposure, ethanol and copper(II) on the formation of a precursor for xanthylium cations from tartaric acid

Influence of light exposure, ethanol and copper(II) on the formation of a precursor for... The production of xanthylium cation pigments was greatly increased when an aged, tartaric acid buffered, 12% (v/v) aqueous ethanol solution was used in a model white wine system. This suggested the formation of a precursor to the pigments during the ageing of the tartaric acid solution. On examining factors responsible for the generation of tartaric acid oxidation products in wine‐like solutions it was observed that on exposure of samples to sunlight, glyoxylic acid, a known precursor to xanthylium cations, was produced. The production of glyoxylic acid was achieved in both the absence and presence of ethanol and copper(II). Hydrogen peroxide was also detected in these solutions. The results were consistent with the presence of glyoxylic acid in the aged tartaric acid buffered, 12% (v/v) aqueous ethanol solution that had frequent aeration and periodic exposure to sunlight throughout its storage. Studies on the role of hydrogen peroxide in the production of glyoxylic acid were also investigated. On the addition of hydrogen peroxide to tartaric acid solutions, with heating at 45°C in darkness, glyoxylic acid was only determined in solutions without ethanol. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australian Journal of Grape and Wine Research Wiley

Influence of light exposure, ethanol and copper(II) on the formation of a precursor for xanthylium cations from tartaric acid

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References (26)

Publisher
Wiley
Copyright
Copyright © 2003 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1322-7130
eISSN
1755-0238
DOI
10.1111/j.1755-0238.2003.tb00233.x
Publisher site
See Article on Publisher Site

Abstract

The production of xanthylium cation pigments was greatly increased when an aged, tartaric acid buffered, 12% (v/v) aqueous ethanol solution was used in a model white wine system. This suggested the formation of a precursor to the pigments during the ageing of the tartaric acid solution. On examining factors responsible for the generation of tartaric acid oxidation products in wine‐like solutions it was observed that on exposure of samples to sunlight, glyoxylic acid, a known precursor to xanthylium cations, was produced. The production of glyoxylic acid was achieved in both the absence and presence of ethanol and copper(II). Hydrogen peroxide was also detected in these solutions. The results were consistent with the presence of glyoxylic acid in the aged tartaric acid buffered, 12% (v/v) aqueous ethanol solution that had frequent aeration and periodic exposure to sunlight throughout its storage. Studies on the role of hydrogen peroxide in the production of glyoxylic acid were also investigated. On the addition of hydrogen peroxide to tartaric acid solutions, with heating at 45°C in darkness, glyoxylic acid was only determined in solutions without ethanol.

Journal

Australian Journal of Grape and Wine Research – Wiley

Published: Apr 1, 2003

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