Dependence between colour and individual anthocyanin content in ripening grapes

Three red grape cultivars of different coloration (Flame seedless, Exotic a nd Monastrell), grown in Murcia (southeast Spain) were analysed during ripe ning for external colour and individual pigment content. The application of the CIRG colour index, calculated from the coordinates hue angle (h), ligh tness (L*) and chroma (C*) of the CIELAB colour space, and defined as [(180 -h)/(L* + C*)], permitted an objective evaluation of the colour at the diff erent ripening stages. External colour and anthocyanic profile were closely linked. Cyanidin-3-glucoside was the most abundant pigment in Flame seedle ss (low pigmented cultivar), while malvidin-3-glucoside was the main anthoc yanin in the cultivars Monastrell and Exotic (both of them with a high pigm ent content). Data derived from the study of the ratios between anthocyanin s with different degree of hydroxilation and/or methoxylation leads to know information on differences between grapevines linked to the synthesis of t hese pigments. (C) 1999 Canadian Institute of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.