OPTIMIZATION OF EXTRACTION AND DEVELOPMENT OF AN LC-HRMS METHOD TO QUANTIFY GLUTATHIONE IN WHITE WINE LEES AND YEAST DERIVATIVES
Glutathione is a natural tripeptide composed of l-glutamate, l-cysteine and glycine, found in various foods and beverages. In particular, glutathione can be found in its reduced (GSH) or oxidized form (GSSG) in must, wine or yeasts¹. Numerous studies have highlighted the importance of GSH in wine quality and aging potential². During winemaking, especially during aging on lees, GSH helps prevent the harmful effects of oxidation on the aroma of the wine³. Nevertheless, the amounts of GSH/GSSG present in wine lees are often unknown and the choice of operating conditions (quantity of lees and aging time) remains empirical.
Based on these observations, the present work aims at proposing an optimized method to extract and quantify the potential of glutathione from white wine lees and yeast derivatives. In this context, several parameters, such as the type of solvent, the extraction time and the solid-liquid ratio, were investigated. For each matrix, the optimization study was carried out using the Box-Behnken Design (3-factor, 3-level) based on 33 factorial experiments. The results showed that the main factor influencing the extraction efficiency was the ethanol concentration. After development and validation of a liquid chromatography−high resolution mass spectrometry quantitation method, GSH and GSSG were assayed in various white wine lees and yeast derivatives in order to investigate the influence of oenological parameters on their content. The results showed differences in concentration depending on the grape varieties and strains used.
For the first time, this study focused on the use of design of experiments and analytical techniques to highlight the presence of glutathione in wine lees and yeast derivatives. Moreover, this research offers promising perspectives for a better understanding of lees antioxidant potential during wine aging. More generally, by-products such as lees can provide new natural products to the food industry, with safer and better antioxidant qualities against oxidative damage.
Issue: OENO Macrowine 2023
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Glutathione, wine lees, RSM design, quantiﬁcation