italianoenglishfrançaisdeutschespañolportuguês
Language
Search
  • » Technical Articles
  • » Evaluating analytical methods for quantification of glutathione in grape juice and wine
  • How to better manage your wine shelf-life
    Three free webinars in collaboration with Vinventions
    Infowine in partnership with Vinventions invites you to a series of 3 webinars focused on the key parameters you need to monitor at different winemaking stages to optimize wine profile and its long...
    Published on: 10/18/2021

Evaluating analytical methods for quantification of glutathione in grape juice and wine

Ágnes DIENES-NAGY, Frédéric VUICHARD, Marie BLACKFORD, Fabrice LORENZINI
Agroscope, Nyon, Switzerland
Email contact:
agnes.dienes-nagy[@]agroscope.admin.ch

 

AIM: Glutathione (GSH) is a powerful natural antioxidant, considered as a promising molecule against oxidative damage of aroma during winemaking and storage. His concentration in the grape juice is variable. Enological practice in the cellar can promote the preservation of the GSH in the grape juice. Recently the prescription of OIV allows to add glutathione rich substances to the must. This new practice creates an increasing interest in the quantification of GSH. Several analytical methods were published to measure GSH[1,2,3,4] and his dimer (GSSG) separately[5] or together as total glutathione[6] content. In this work we compared two analytical methods for the analyses of grape juice and wine samples.

METHODS: The first method is an enzymatic assay (EA), based on the reaction of thiol with DTNB in the presence of glutathione reductase enzyme to measure the total glutathione content. This method was automatized to allow high through-put measurements in the concentration range of 5-100mg/l.
The second method, using UPLC-MS/MS, is more sensitive (LOD = 0.5mg/l) and permits simultaneous quantification of GSH, GSSG and additionally the sulfonated form of glutathione (GSSO3H).

RESULTS: The best results were obtained with 2.5g/l ascorbic acid. Using the two analytical methods, we found a strong correlation (R2=0.98) between the total glutathione (EA) and the sum of GSH and GSSG (UPLC-MS/MS) in grape juice samples (n>100), where the GSSO3H concentration was low (0-8 mg/l) comparing to the GSH and GSSG (5-100mg/l). In wine samples the total glutathione concentration was low (2-7mg/l) and the GSSO3H was more important (5-9mg/l) due to the combination of SO2 with the glutathione. View the high reactivity of GSH, a special attention should be accorded to the preparation and the storage of grape juice samples. We compared the effect of different concentration of SO2 and ascorbic acid as additives and found that 2.5g/l ascorbic acid gave the best results.

CONCLUSION: Based on our results the enzymatic assay is an economic alternative to measure the total glutathione concentration of grape juice. However for wine the UPLC-MS/MS method is recommended, to reach the necessary sensitivity and to analyze all glutathione species.

 

References:

[1] Lavigne, V.,Pons, A. & Dubourdieu, D. Journal of Chromatography A 2007, 1139, 130-135
[2] Janes, L., Lisjak, K. & Vanzo, A. Analytica Chimica Acta 2010, 674, 239-242
[3] du Toit, W. J., Lisjak, K., Stander, M., & Prevoo, D. J Agric Food Che., 2007 55(8), 2765-2769
[4] Roland, A. & Schneider, R. Food Chemistry 2015, 177, 152-157
[5] Marchand, S. & de Revel, G. Analytica Chimica Act, 2010, 660, 158-163
[6] Adams, O. D. & Liyanage, Ch. Am. J. Enol.Vitic. 1991, 42(8), 137-140

Published on 06/18/2018
Pictures
Related sheets
© All Right Reserved
ISSN 1826-1590 VAT: IT01286830334
powered by Infonet Srl Piacenza
Privacy Policy
This website and its related third-party services make use of cookies necessary for the purposes described in the cookie policy. If you want to learn more about cookies or how to disable them (either totally or partially), please see the cookie policy. By closing this banner, scrolling through this page, clicking on a link or continuing navigation in any other way, you consent to the use of cookies.
More informationOK

- A +
ExecTime : 1,811523