Red wine oxidation: oxygen consumption kinetics and high resolution UPLC-MS analysis

S. DESHAIES¹, G. CAZALS², C. ENJALBAL², F. GARCIA¹, L. MOULS¹, C. SAUCIER¹
1SPO, Univ Montpellier, INRA, Montpellier SupAgro, Montpellier, France.
2IBMM, Univ Montpellier, Montpellier, France

Email contact: cedric.saucier[@]umontpellier.fr

Oxygen is playing a major role in wine ageing and conservation. Many chemical oxidation reactions occur but they are difficult to follow due to their slow reaction times and the numerous resulting reaction products. There is a need for global and rapid in vitro tests to predict wine oxidation kinetics. First, three different forced oxidation protocols were developed on a “young” (2018) red wine to follow the consumption of oxygen.

After oxygen saturation of the wines at 22°C, the red wines were oxidized following 3 different protocols

1 – heat at 60°C

2 –laccase oxidation at 22°C

3 –hydrogen peroxide oxidation at 22°C

The oxygen consumption kinetics were followed by oxo-luminescence oxygen measurements. The oxygen consumption all followed a first order kinetic on the 2018 wine but had different kinetics constants depending on the oxidation protocol. High resolution UPLC-MS was also performed on forced oxidation samples and compared to natural oxidation samples of naturally aged red wines (2014 and 2010 vintages). Specific polyphenols (anthocyanins, flavanols and their derivatives) were impacted in both naturally or artificially aged wines and differed depending on the oxidation protocol. For example, the intensity of some low molecular weight polyphenols increased both in naturally or artificially heated aged wines ([M+H]⁺= 287; 289; 291; 303; 317; 319). However, some differences were observed between natural and artificial aging for higher molecular weight polyphenols ([M+H]⁺= 493; 535;  639)