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.
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