Macrowine 2021
IVES 9 IVES Conference Series 9 Evaluating analytical methods for quantification of glutathione in grape juice and wine

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

Abstract

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.

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Ágnes Dienes-Nagy

Agroscope, Nyon, Switzerland,Frédéric VUICHARD, Agroscope, Nyon, Switzerland Marie BLACKFORD, Agroscope, Nyon, Switzerland Fabrice LORENZINI, Agroscope, Nyon, Switzerland

Contact the author

Keywords

glutathione, enzymatic assay, uplc-ms/ms

Citation

Related articles…

Under-vine management effects on grapevine vegetative growth, gas exchange and rhizosphere microbial diversity

The use of cover crops under the vines might be an alternative to the use of herbicides or tillage, improving grapevine quality and soil characteristics. The aim of this research was to study the implications of different management strategies of the soil under the vines (herbicide, cultivation or cover crops) on grapevine growth, water and nutritional status, gas exchange parameters and belowground microbial communities.
The experimental design consisted in 4 treatments applied on 35L-potted Tempranillo vegetative grapevines with 10 replicates each grown in an open-top greenhouse in 2022 and 2023. Treatments included two cover crop species (Trifolium fragiferum and Bromus repens), herbicide (glyphosate al 36%) and an untreated control.

Read More

Effect of soil texture on early bud burst

Notre objectif est d’étudier de façon précise les relations entre la physiologie de la vigne et le sol, en prenant en compte l’effet millésime. Nous avons plus précisément étudier la précocité de débourrement de la vigne (stade D) en fonction de la texture du sol et plus particulièrement de la teneur en éléments grossiers.

Read More

Ultra-High Pressure Homogenization (UHPH): a technique that allows the reduction of SO2 in winemaking

Ultra-High Pressure Homogenization (UHPH) is an innovative, efficient and non-thermal technology that can be applied at different stages in winemaking in order to reduce or avoid the use of sulphites. During 2022 vintage, a batch of Xarel·lo must was processed by UHPH at 300 MPa with an inlet temperature (Ti) of 4 ºC. In order to verify the influence of the UHPH treatment in wine characteristics, alcoholic fermentations with this must (UHPH) were carried out and compared with a control batch (without SO2 addition (C)) and a sulphited batch, in which 60 mg/L of total SO2 (SO2) were added.

Read More

Terroir and Typicity: proposed definitions for two essential concepts in the understanding of Geographical Indications and sustainable development

The content of this communication arises from the deliberations of a working group mandated within the framework of the INRA-INAO 2000-2003 research convention, which brought together INAO representatives and researchers who had worked on AOCs or PGIs, in disciplines from the sphere of the humanities (consumer science, marketing, rural development) and biotechnical sciences (agronomy, animal production science, technology, biochemistry).

Read More

Eugenol:  a new marker of hybrid vines? The case study of Baco Blanc in Armagnac

Nowadays, winemaking is dealing with great challenges, notably climate change, disease resistance and low pesticide inputs, desire for more sustainable agricultural productions and permanent changing of consumer preference. Trying to propose practice improvements, scientists are exploring vine hybridization a paradoxically old but still actual way to take up such challenges

Read More