Anthocyanins are the compounds responsible for the colours in
several different fruits (Mazza & Miniati, 1993). In grapes, they are
found almost exclusively in the skins, with only a limited number
of varieties showing these compounds in the pomace. They are of
particular importance in grapes, given that following fermentation
of the must, these compounds are responsible for red colour in red
wines (Cheynier, Moutounet, & Sarni-Machado, 2000). For this reason,
and also due to the variations which occur in them as the
grape is ripening, their development in the grape must be characterised
in order to determine the most suitable date for the harvest.
Anthocyanins are not the only compounds to be analysed for determining
the best harvest time; however for red grapes they have a
special significance. As it is a solid sample, the analysis process
usually begins with extraction of the anthocyanins using organic
solvents either with or without water, and at different pH values