Anthocyanin Copigmentation - Evaluation, Mechanisms and Implications for the Colour of Red Wines

Copigmentation is the main colour-stabilizing mechanism in plants and in food products of vegetable origin. It is a spontaneous and exothermic process that consists of the stacking of an organic molecule, called copigment, on the planar polarizable moieties of the anthocyanin coloured forms. Although this phenomenon has long been described, there are some aspects that are still not well understood or controversial like the nature of the interaction pigment to copigment, the way to quantify the extent of the process, its effect on other anthocyanin properties like astringency or reactivity. In this article a review of the most significant advances achieved in the last years in the field of intramolecular and intermolecular copigmentation is presented. Also, the most recent findings regarding wine copigments and their effects on the colour of red wines are revised. Keywords: Copigmentation, Red-wine, Anthocyanin, Copigment, Self-association, hemiketals, light-yellow chalcone structures, flavylium ion, acidic solutions, anthocyanins, copigmentation phenomenon, exothermic process, planar polarizable moieties