Impact of Sample Storage Conditions on Phenolic Profiles of Commercial Wines Assessed by UHPLC-HRMS: Implications for Analytical Reproducibility

Metabolomic approaches for wine analysis provide multiple data points for determining quality and traceability. However, sample storage is a major bottleneck and can strongly affect wine composition. We aliquoted wine samples into small tubes and stored them under 4 different conditions (room temperature, +4 °C, −20 °C, and −80 °C). We tracked wine polyphenol composition over two years using targeted HPLC-HRMS. We established the need for reliable quality controls kept at −80 °C to correct batch effects during the study. We observed a general stability trend: phenolic acids > flavonols > flavanols > stilbenes. However, each class showed specific behaviours. As expected, −20 °C and −80 °C were the best conditions and were nearly equivalent, while room temperature caused rapid degradation of almost all polyphenols. Interestingly, we could find satisfactory stability for most polyphenols at +4 °C after 6 months. This was confirmed by assessing the ability to discriminate wines by cultivar. After 24 months of storage, we observed no discrimination for samples kept at room temperature. Our results improve the understanding of how wine storage affects metabolomic studies when samples cannot be collected and analysed simultaneously.