Rapid assessment of wine oxidative stability combining climatic chamber stress tests and EPR spectroscopy

Abstract

Accurate prediction of wine shelf life is crucial for quality and economic value. Since real ageing studies are time-consuming, accelerated tests simulate long-term chemical and sensory changes in shorter times, enabling rapid evaluation of oxidative stability, aroma loss, and phenolic evolution through kinetic models. Beyond colour metrics, the innovative Electron Paramagnetic Resonance (EPR) spectroscopy can offer complementary mode-of-action insight by tracking radicals and antioxidant capacity, correlating with oxidation markers and being possibly combined with accelerated tests.

In the present study, 22 white wines from different grape varieties (Grechetto, Trebbiano, Vermentino, Fiano) were subjected to accelerated ageing tests in climatic chambers to evaluate oxidative and colour stability. Real storage trials lasted up to 12 months at 15 and/or 23 °C. In parallel, micro-vinifications from Grechetto, Trebbiano and Vermentino grapes were conducted under controlled conditions to investigate the effects of different oenological strategies on wine stability. EPR spectroscopy was also applied for the prediction of the shelf life.

A strong and statistically significant correlation was observed between the colour variation (ΔE) measured under accelerated and real storage conditions. Linear regression analysis yielded a high coefficient of determination (R² = 0.851), indicating that a substantial proportion of the colour changes occurring during real ageing can be explained by accelerated approaches. The regression slope (≈1.07), close to unity, suggests a comparable extent of colour evolution under accelerated and real storage conditions, while the low intercept value indicates minimal systematic bias. Wines exhibiting higher EPR-derived oxidative stability indices showed greater resistance to oxidative changes under both accelerated and real ageing conditions, indicating consistency between instrumental oxidative stability measurements and stress test outcomes.

These results support the suitability of climatic chamber as an effective accelerated shelf life methodology for predicting medium-term colour stability of white wines. The statistically significant correlation (p < 0.01) between climatic chamber ΔE data and EPR-based oxidative stability markers not only further validates the use of climatic chambers as accelerated shelf life tests, but also supports the suitability of EPR spectroscopy as a rapid method for evaluating oxidative stability in white wines.

Acknowledgements

This work was supported by the Italian Ministry of Universities and Research (MUR) and the European Union – NextGenerationEU under the PRIN-PNRR framework, through Project P2022LXY3A (WiSSaTech; Mission 4, Component 2, Investment 1.1 – D.D. 1409/2022) and the project White Wine Identity (PRIN-PNRR “Supply Chain and District Contracts” – MASAF 5th call; PNRR M2C1-I 3.4; CUP B79I21001220001; IRIS ID: PRJ-1058).