Introduction
Foods, particularly fruits and vegetables, are naturally
colored mainly by four groups of pigments: the green
chlorophylls, the yellow-orange-red carotenoids, the redblue-purple
anthocyanins and the red betanin. These
pigments are also incorporated into food products by
direct addition or indirectly through animals’ feed. Although
recent studies have been stimulated and dominated
by their importance in human health, earlier
investigations were motivated by the color they impart.