Redox-dependent metabolomic signatures of red wine aging

Abstract

Oxygen is a central factor in wine evolution, driving a network of redox-mediated chemical and biochemical processes that shape wine quality, stability, and sensory perception. While controlled oxygen exposure can enhance color stability and mouthfeel, excessive oxidation or strongly reductive conditions may lead to chemical imbalance and sensory deterioration. These outcomes result from global shifts in the wine redox environment, affecting multiple molecular families beyond conventional targeted markers.

The aim of this study was to evaluate the impact of oxygen availability on the metabolomic and proteomic space of red wines stored under oxidative and reductive conditions.

Twelve red wines were selected, including six young wines intended for early consumption and six aged wines with a longer expected shelf life. Samples were stored under three conditions: control (anoxic, 6 °C, 10 weeks), thermal stress (anoxic, 35 °C, 10 weeks), and oxidation (35 mg L⁻¹ dissolved oxygen, 35 °C, 10 weeks). Redox potential was measured in all samples to confirm the coherence of the experimental design. Untargeted metabolomic profiling was performed using UPLC–HRMS–QTOF to obtain metabolic fingerprints, complemented by targeted analyses. Preliminary proteomic analyses (HPLC-MS/MS Orbitrap) were conducted in control and thermally stressed samples. Data processing followed an in-house workflow for quality control, feature selection, and tentative biomarker annotation.

Untargeted LC–MS analysis generated over 10,000 features, from which approximately 600 statistically relevant markers were selected and grouped according to their response to oxygen. Putative annotation indicated the involvement of phenolic compounds, anthocyanin-related species, and sulfonated derivatives. Several anthocyanin-related signals decreased markedly under oxidative conditions, while others showed slower decreases under anoxic storage. Sulfonated flavanol- and indole-related features were predominantly associated with anoxic conditions, particularly under thermal stress. Preliminary untargeted proteomic analysis led to the tentative identification of 64 proteins and peptides (FDR<1%) whose abundance differed between control and thermally stressed samples.

Overall, this study highlights the potential of untargeted metabolomics to capture redox driven molecular signatures in red wine aging, enabling discrimination of oxidative and reductive aging trajectories beyond targeted chemical markers.

Acknowledgements

Work funded by the Spanish MICCIN PID2021-126031OB-C22. I.A. received the grant (198/2025) funded by Gobierno de La Rioja, Consejería de Economía, Innovación, Empresa y Trabajo Autónomo.