Browning susceptibility of white wine and antioxidant effect of glutathione

Abstract

Glutathione (GSH) content and other physicochemical parameters of thirteen white wines originated from Lebanon were studied in relation to their browning capacity; the impact of pH, total sulphur dioxide and total phenol content into the browning susceptibility of the wine was shown. The effect of GSH, added to the wine at different concentrations, on the total phenol content was studied at 55°C during 8 days of accelerated oxidation. GSH addition resulted in significantly higher total phenol content only on day 0 of the test. GSH was shown to be readily oxidised in these conditions: even on day 0, there was a considerable reduction (up to 73%) in GSH level. Moreover, after 8 days of oxidation, GSH concentration in all studied samples ranged from 4.79 to 5.11 mg L )1 ; these values were close to GSH value in control wine (without added GSH) on day 0. On the contrary, GSH appeared to contribute significantly to the wine stability, which might have been via the increase of reduced phenolic pool. GSH addition appeared to have an improving effect on the organoleptic qualities of the wine.

Potential use of new Colombian sources of betalains. Colorimetric study of red prickly pear (Opuntia dillenii) extracts under different technological conditions

“…Thus, cold conditions permitted a better conservation of the initial lightness of the extracts. It is remarkable that, for both hue (h ab ) and lightness (L*), samples kept at 20°C for 12 days showed similarly values than those heated at 80°C in only 5 h. That fact evidenced that the color degradation of O. dillenii was accelerated by the thermal treatment, as affirmed (El Hosry, Auezova, Sakr, & Hajj-Moussa, 2009). …”

Reversed-Phase High-Performance Liquid Chromatography–Fluorescence Detection for the Analysis of Glutathione and Its Precursor γ-Glutamyl Cysteine in Wines and Model Wines Supplemented with Oenological Inactive Dry Yeast Preparations

“…In fact, this effect has been previously observed in the study by Patel and collaborators (2010), in which a must added with a high content of GSH (67 mg L −1 ) decreased considerably its concentration until few milligrammes per litre after alcoholic fermentation. In spite of that, it has also been shown that wines from musts supplemented with GSH experienced slighter oxidation symptoms and exhibited better sensory characteristics than control wines (without GSH added to the must) (El Hosry et al 2009). Finally, the progressive reduction in reduced GSH observed during the shelf life of the wine (Fig.…”

Quantification of glutathione, catechin and caffeic acid in grape juice and wine by a novel ultra-performance liquid chromatography method

“…In this way the formation of o-quinones and, consequently, the production of browning polymers, is limited. GSH can thus have a positive effect on white wine colour, appearing to make the colour more stable during ageing (Hosry, Auezova, Sakr, & Hajj-Moussa, 2009;Lavigne & Dubourdieu, 2004;Vaimakis & Roussis, 1996).…”