Short- and long-term effects of micro-oxygenation treatments on the colour and phenolic composition of a Cabernet Sauvignon wine aged in barrels and/or bottles

Abstract

Micro-oxygenation is the controlled and continuous addition of small doses of oxygen to the wine in order to achieve a rational management of the evolution of the colour and mouthfeel properties of red wines. The short and, especially, the long-term effects of this technology on the colour characteristics of wines are still little known. In this study, a Cabernet Sauvignon wine was subjected to oxygenation treatments before (15 mg O2/L in 3 weeks) and after (6 mg O2/L in 3 months) malolactic fermentation and then aged for 20 months in barrels and/or bottles. Analysis was carried out of the dissolved oxygen concentration, the acetaldehyde content, and the evolution of several parameters related to the anthocyanic composition and the chromatic characteristics of wines for 113 weeks. The supplying oxygen significantly accelerated the kinetics of the degradation and transformation reactions of anthocyanins providing wines with a more intense bisulphite non-bleachable colour, with little or not impact on the normal evolution of their tonality. These beneficial effects produced during the treatments were kept over time, in such a way that the differences between the micro-oxygenated wines and the control wines remained after 20 months of ageing.