Younger red wines are likely to be more beneficial than aged wines, a study from Australia has found, due to the significant decrease in healthy antioxidants in wine over time.
The study, conducted by Australian’s Central Queensland’s CQ University and published in the Australian Journal of Grape and Wine Research, looked at 16 wines from Australia and New Zealand that ranged in age from one to six years old, to see the effect of ageing on trans-resveratrol, a naturally occurring antioxidant in grapes and red wine that has been proven to have cardiovascular, anti-inflammatory, and anti-diabetic effects.
The researchers expected the concentration of free trans-resveratrol in wine to increase with storage because of hydrolysis of the resveratrol (the chemical breakdown of the biocompound as it reacts with water), however after researchers tested the wines at the start of the study and again after 16 months storage, they found that concentrations of trans-resveratrol in the wine had decreased by an average of 76% over time, with decay rate proving independent of the growing conditions or year of vintage.
The researchers say that the data suggests that transformation of trans- to cis-resveratrol takes place due to residual enzymatic activity (rather than being catalysed by light or acid). In general, this may reduce the anticipated health benefits of the wine given that cis-resveratrol displays fewer health benefits than the trans isomer.
Source: Naiker, M., Anderson, S., Johnson, J., Mani, J., Wakeling, L. and Bowry, V. (2020), Loss of trans-resveratrol during storage and ageing of red wines. Australian Journal of Grape and Wine Research.