Antioxidant Action of Glutathione and the Ascorbic Acid/Glutathione Pair in a Model White Wine

Abstract

Glutathione was assessed individually, and in combination with ascorbic acid, for its ability to act as an antioxidant with respect to color development in an oxidizing model white wine system. Glutathione was utilized at concentrations normally found in wine (30 mg/L), as well as at concentrations 20-fold higher (860 mg/L), the latter to afford ascorbic acid (500 mg/L) to glutathione ratios of 1:1. The model wine systems were stored at 45 °C without sulfur dioxide and at saturated oxygen levels, thereby in conditions highly conducive to oxidation. Under these conditions the results demonstrated the higher concentration of glutathione could initially provide protection against oxidative coloration, but eventually induced color formation. In the period during which glutathione offered a protective effect, the production of xanthylium cation pigment precursors and o-quinone-derived phenolic compounds was limited. When glutathione induced coloration, polymeric pigments were formed, but these were different from those found in model wine solutions without glutathione. In the presence of ascorbic acid, high concentrations of glutathione were able to delay the decay in ascorbic acid and inhibit the reaction of ascorbic acid degradation products with the wine flavanol compound (+)-catechin. However, on depletion, the glutathione again induced the production of a range of different polymeric pigments. These results highlight new mechanisms through which glutathione can offer both protection and spoilage during the oxidative coloration of a model wine.

Influence of ascorbic acid, sulfur dioxide and glutathione on oxidation product formation in wine-like systems

“…Contrary to what was expected, GSH addition triggered xanthylium cation formation under the conditions tested. At a molar ratio of GSH to (+)-catechin of almost 1:1, one assumption is the already reported polymeric pigment formation due to GSH depletion [3]. This depletion may be ascribed to GSSG or o-quinone addition products formation.…”

“…The main anti-oxidative activity of SO 2 is the reaction of the bisulfite ion with H 2 O 2 to form sulfuric acid, changing the oxidation state of sulfur from +IV to +VI, AA can directly react with molecular oxygen to generate dehydroascorbic acid and H 2 O 2 . The reaction of GSH seems to be either via the reaction with active oxygen species to form the glutathione disulfide (GSSG) or to form addition products with carbonyl or o-quinone compounds [3,4]. Negative oxidative evolution of white wines can result in the loss of pleasant aroma compounds, increase in acetaldehyde concentration or oxidative color evolution.…”

Sulfur Dioxide and Glutathione Alter the Outcome of Microoxygenation

“…It is known that GSH binds acetaldehyde (Sonni et al 2011b) and that oxidation of GSH yields several oxidation products when it reacts with hydrogen peroxide in aqueous solution at pH values close to that of wine (Finley et al 1981). Thus, it seems possible that this molecule exerts a protective function in wine by several possible mechanisms: (i) scavenging hydrogen peroxide, (ii) by direct reaction with wine phenolics (Bouzanquet et al 2012, Sonni et al 2011a by way of quinones (Nikolantonaki and Waterhouse 2012), and (iii) binding acetaldehyde to a less extent with respect to SO 2 (Sonni et al 2011b). A synergic effect of SO 2 and GSH is also not ruled out.…”

Sauvignon Blanc Wine: Contribution of Ageing and Oxygen on Aromatic and Non-aromatic Compounds and Sensory Composition : A Review

“…Glutathione is also capable of carrying out nucleophilic reactions with other compounds such as aldehydes (Cheynier et al, 1986;Cheynier & Van Hulst, 1988;Sonni et al, 2011) and has protective abilities toward important aroma compounds such as esters, monoterpenes and volatile thiols (Papadopoulou & Roussis, 2001;Lavigne-Cruège & Dubourdieu, 2003;Roussis et al, 2007;Papadopoulou & Roussis, 2008). However, GSH has also been shown to induce the production of H 2 S during wine ageing under lowoxygen conditions (Ugliano et al, 2011).…”