Copigmentation, colour and antioxidant activity of single-cultivar red wines

Abstract

a hundred and thirty-six single-cultivar red wines of different vintages were collected from several wineries in the Canary Islands in order to study the magnitude of the copigmentation phenomenon and the antioxidant activity. The contribution of free anthocyanins, copigmented anthocyanins and polymeric pigments to the colour of wine, as well as the total phenols, the antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, DPPH method) and the chromatic characteristics of the wines were determined. The influence of ageing time and the climatic conditions on these parameters was also studied. The wines made with Merlot, Ruby Cabernet and Syrah cultivars showed the highest parameters of colour, and the largest contribution to the copigmented anthocyanins was from the Ruby Cabernet, listán negro and Syrah cultivars. The copigmented anthocyanins and the free anthocyanins decrease with the age of the wine, and the antioxidant activity of the samples appears to be related to the total phenol content. an influence of the climatic conditions on colour parameters has been found. The correlation study between parameters suggests that the parameters b* and L* could be used as suitable indicators of evolution or oxidation stage of red wines.