Optimization Of Glutathione Extraction From White Wine Lees By Doelhert Matrix

Abstract

Glutathione (L-g-glutamyl-L-cysteinyl-glycine) is a tripeptide which contains three constitutive amino acids: glutamate, cysteine and glycine. It is present in plants and foods, and fruits like grapes. In must, wine or even yeast, glutathione can be found under its reduced (GSH) or oxidized form (GSSG) [1,2].  Many studies have proven that GSH plays a key role in wine quality and longevity [3]. It is well proved that during winemaking, particularly during wine aging on lees, the GSH concentration in wine increases and protects it from oxidation phenomena [4]. Nevertheless, the amount of GSH present in wine lees is often unknown and the choice of operating conditions (amount of lees and aging time) remains empirical. The aim of this study was to propose an optimized method to extract and to quantify the GSH potential of wine lees. In order to assess the main parameters affecting GSH extraction, the type of solvent, extraction time and solid-liquid ratio were investigated. A Response Surface Methodology (RSM) by Doehlert matrix, an useful tool for optimizing specific compound extraction, was applied to optimize GSH extraction from white lees. The results show that water is a suitable solvent for GSH extraction and that the solid-liquid ratio (< 15 g/L) and the extraction time (< 1h) are the main parameters that influence GSH extraction from lees. This approach was extended to the analysis of GSH present in enological product as yeast derivatives. This work in very helpful for developing a cost effective process for extraction of GSH from winemaking wastes as well as to analyze the GSH evolution in lees during winemaking in order to control operating condition of wine aging.

References

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