Red Wine Oxidation: Accelerated Ageing Tests, Possible Reaction Mechanisms and Application to Syrah Red Wines.

Stacy Deshaies,Thibaut Constantin,Christine Enjalbal,Cédric Saucier,Guillaume Cazals,Laetitia Mouls,François Garcia

doi:10.3390/antiox9080663

Abstract

Wine oxidation and ageing involve many complex chemical pathways and reaction mechanisms. The purpose of this study is to set up new and reproducible accelerated red wine ageing tests and identify chemical oxidation or ageing molecular markers. Three accelerated and reproducible ageing tests were developed: a heat test (60 °C); an enzymatic test (laccase test; a chemical test (hydrogen peroxide test). Depending on the test, oxygen consumption was significantly different. For a young wine (2018), the oxygen consumption rate moved from 2.40 ppm·h−1 for the heat test to 3.33 ppm·h−1 for the enzymatic test and 2.86 ppm·h−1 for the chemical test. Once applied to two other vintages (2010 and 2014) from the same winery, the tests revealed different comportments corresponding to wine natural evolution. High resolution UPLC-MS was performed on forced ageing samples and compared to naturally aged red wines. Specific oxidation or ageing ion markers were found with significant differences between tests, revealing the specificity of each test and different possible molecular pathways involved. The hydrogen peroxide test seems to be closer to natural oxidation with an important decrease in absorbance at 520 nm and similar molecular ion variations for [M+H]+ = 291, 331, 347, 493, 535, 581, 639 Da.

Highlights

Oxygen has an important role in chemical reactions in red wines from the winemaking process to bottle ageing
Threewines reproducible accelerated ageing Ion testsintensities based on three oxidation protocols were developed in the Syrah from different vintages
Three reproducible accelerated ageing tests based on three oxidation protocols were developed in this study and tested on three Syrah red wine samples

Summary

Introduction

Oxygen has an important role in chemical reactions in red wines from the winemaking process to bottle ageing. An optimal red wine quality is correlated with a moderate oxygen exposure during the whole wine lifetime [3]. One example is its consumption by yeasts to produce sterols during alcoholic fermentation. This allows them to have better alcohol resistance and nitrogen nutrient absorption. From an organoleptic point of view, an optimal oxygen exposure may reduce some wine negative aspects, such as bitterness or astringency [3,6]. A too high oxygen exposure will reduce antioxidant concentrations (sulfur dioxide or ascorbic acid) and desirable volatile compounds, affecting wine quality [8]

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