Evolution of the colour, antioxidant activity and polyphenols in unusually aged Sherry wines.

The present paper reports the results of a study monitoring several key analytical parameters in a set of aged samples of vintages from 1999 back to 1935. The analysed parameters were: colour, antioxidant activity, low molecular weight phenolics, index of total polyphenols and SO2 content. It can be concluded that the antioxidant activity of the old wines studied is clearly related to the ageing time and to the polyphenols extracted from the wood during this period. The wines also showed differences in their chromatic characteristics according to the duration of their ageing in years. A principal component analysis confirmed that most of the studied variables (except hydroximethylfurfural and SO2) are strictly linked to ageing, which allowed a discrimination of 100% of the wines belonging to different decades, according to the results obtained by means of the application of linear discriminant analysis.