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IVES 9 IVES Conference Series 9 OPTIMIZATION, VALIDATION AND APPLICATION OF THE EPR SPIN-TRAPPING TECHNIQUE TO THE DETECTION OF FREE RADICALS IN CHARDONNAY WINES

OPTIMIZATION, VALIDATION AND APPLICATION OF THE EPR SPIN-TRAPPING TECHNIQUE TO THE DETECTION OF FREE RADICALS IN CHARDONNAY WINES

Abstract

The aging potential of Burgundy chardonnay wines is considered as quality indicator. However, some of them exhibit higher oxidative sensitivity and premature oxidative aging symptoms, which are potentially induced by no-enzymatic oxidation such as Fenton-type reaction (Danilewicz, 2003). This chemical mechanism involves the action of transition metal, native phenolic compounds and oxygen which promote the generation of highly reactive oxygen species (ROS) such as hydroxyl radicals (OH) or 1-hydroxyethyl radicals (1-HER) from oxidation of ethanol. Such mechanism is involved in the radical oxidation occurring during bottle aging. According to Elias et al.,(2009a), the 1-HER is the most abundant radical in forced oxidation treated wines. Consequently, understanding its evolution kinetic in dry white wines is of great importance. Due to the reactivity (Danilewicz, 2003) and short half-life (10-6-10-9s) of ROS in aqueous solution (Pryor, 1986), their direct quantitation in wine is impossible. However, by means of spin-trapping technique, the radicals can form relatively stable adducts with spin-trap, and thus be monitored in real-time by electron paramagnetic resonance (EPR) (Elias et al., 2009b).

This study aims to optimize and validate an EPR spin trapping method using POBN as spin trap, to monitor the formation kinetic of 1-HER in chardonnay white wine and investigate the impact of some enological parameters (pH, ethanol, acidity, sulfites) on their formation. 1-HERs were generated by Fenton reaction (Fe²+ and H₂O₂) in chardonnay wines. The relative amount of reactant was optimized. In addition, several strategies were developed to decrease the impact of bisulfite on the detection of EPR signal. Finally, the analytical method was validated in terms of repeatability and reproducibility and applied to many chardonnay wines. To some extent, this study provides new insights into radical behavior that may contribute to comprehensive understanding of the oxidative stability of chardonnay white wines.

 

1. Danilewicz, J.C., 2003. Review of Reaction Mechanisms of Oxygen and Proposed Intermediate Reduction Products in Wine: Central Role of Iron and Copper. Am. J. Enol. Vitic. 54, 73–85.
2. Elias, R.J., Andersen, M.L., Skibsted, L.H., Waterhouse, A.L., 2009a. Key Factors Affecting Radical Formation in Wine Studied by Spin Trapping and EPR Spectroscopy. Am. J. Enol. Vitic. 60, 471–476.
3. Elias, R.J., Andersen, M.L., Skibsted, L.H., Waterhouse, A.L., 2009b. Identification of Free Radical Intermediates in Oxidized Wine Using Electron Paramagnetic Resonance Spin Trapping. J. Agric. Food Chem. 57, 4359–4365.
4. Pryor, W.A., 1986. Oxy-Radicals and Related Species: Their Formation, Lifetimes, and Reactions. Annu. Rev. Physiol. 48, 657–667.

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Pei Han 1,2, Alexandre Pons1,2,3
1. Univ. Bordeaux, Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, F-33140 Villenave d’Ornon, France
2. Bordeaux Sciences Agro, Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, F-33170 Gradignan, France
3. Seguin Moreau France, Z.I. Merpins, BP 94, 16103 Cognac, France

Contact the author*

Keywords

chardonnay, radical, wine oxidation, EPR

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

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