Targeted and untargeted UHPLC-MS metabolomic approaches for the study of the stability of monovarietal wine samples over time

Abstract

Metabolomics approaches are highly suitable for studying complex topics in wine traceability, the effects of global warming on wine components, the development of new resistant grape varieties, and the relationships between composition and wine quality traits. However, because the wine matrix is constantly evolving, a major concern in wine metabolomics studies is how to preserve samples before analysis [1]. This concern is particularly important in collaborative metabolomics studies using different platforms. For two years, our laboratory has been analysing the effects of storing wine samples at different temperatures. We selected 38 commercial monovarietal French wines, mainly from the Pays d’Oc region, including Cabernet-Sauvignon, Merlot, Gamay, and Pinot noir. Wine samples were stored in Eppendorf tubes at four temperatures: room temperature, 4 °C, –20 °C & –80 °C. Analyses were performed after 6 months, 1 year, 1.5 years and 2 years of storage using a UHPLC-HRMS/MS system comprising a QExactive Orbitrap Mass Spectrometer. A targeted analysis of polyphenols was conducted using a calibration curve covering over 50 polyphenols (including flavanols, flavonols, phenolic acids and stilbenes), while an untargeted approach using Full-Scan HRMS with data-dependent fragmentation acquisition in both positive and negative modes was also performed [2]. Preliminary targeted tests at 2 months already showed a significant difference between samples stored at 4 °C and those stored at room temperature, which became striking at 6 months, primarily affecting flavanols and phenolic acids. By comparison, the targeted analysis showed no significant differences at 12 or 18 months for most polyphenols stored at –20 °C or –80 °C. When comparing these samples with those kept at 4 °C, we observed stability of phenolic acids (gallic, caftaric, caffeic) at these temperatures throughout the experiment, variable responses in flavonols and stilbenes (i.e., the expected loss in quercetin but stability of its glycosides), and a marked loss of all flavanols at 4 °C by 6 months (catechin, gallocatechin, procyanidin B 1). The untargeted approaches are providing similar results, with even stronger discrimination between room temperature, 4 °C and –20/–80 °C. Further research will be conducted to identify additional biomarkers specifically involved in these discriminations.

References

1. Vendramin, V., Pizzinato, D., Sparrow, C., Pagni, D., Cascella, F., Carapelli, C., and Vincenzi, S. (2022) Prevention of quercetin precipitation in red wines: a promising enzymatic solution. OENO One, 56, 41–51.
2. Luca Garcia, Benjamin Poulain, Alice Douliez, Eloise Naud, Josep Valls Fonayet, Claudia Nioi. White wine lees as a source of antioxidants: Insights into their chemical profile Food Chemistry. 10.1016/j.foodchem.2025.146118 IF: 7.51