Oxygen consumption and changes in chemical composition of young wines

Abstract

AIM: The study of the capacity to consume oxygen of the wines is an aspect of great interest since it allows to analyse their useful life. This work evaluates the oxygen consumption kinetics of 27 commercial white, rosé and red wines from the Spanish wine-growing region of “Castilla y León” and the effect on its composition.

METHODS: Wines were saturated with oxygen and were monitored its oxygen consumption kinetics. Phenolic and volatile compounds (1,2) were evaluated in the initial wines and after 3 months of permanence in the bottle after undergoing a controlled oxygen saturation.

RESULTS: The oxygen consumption kinetics allowed to establish the differentiating characteristics of each type of wine. The parameters of the curve related to the time required to consume oxygen, the oxygen level at half-time, the area under the curve or the time to reach half-area, allowed to differentiate white wines from rosé and red wines. The variables that allow the differentiation of the 3 types of wines studied were the time to consume 10% of the available oxygen, and the time to consume between 10-90% of the available oxygen.

In general, the red wines showed a greater avidity for oxygen than the white wines. However, it is interesting to note that some white wines presented a consumption kinetics similar to the red ones. In the rosé wines, consumption kinetics were found closer to that of white or red wines, mainly depending on their phenolic characteristics.

The controlled oxygen saturation of wines produced a high decrease of ethyl esters and alcohol acetates in all wines (40-65%) that reduced the fruity and floral notes of the wines. In addition, an increase of Strecker aldehydes was observed in most of the wines (20-28%), compounds that can provoke the appearance of negative notes, such as honey, malty aromas and/or ripe fruit.

Slight decrease in total polyphenols was found in the white and rosé wines, while no significant differences were found in the red ones. On the other hand, in the rosé and red wines, a loss of total anthocyanins was observed together with an increase in polymeric anthocyanins, which produced an increase in colour intensity and tonality.

Conclusions

The oxygen saturation of wines induced a loss of volatile compounds associated to fruity and floral notes and an increase of aldehydes responsible of oxidative notes. In addition, an increase of polymeric anthocyanins was observed in rosé and red wines, which indicates an aging acceleration.

Acknowledgment 

This research was funded by the Junta de Castilla y León thought a collaboration agreement between the ITACyL, the UVa and the UVa Science Park Foundation