Q. What are natural or synthetic food colours?
Food in raw state has a natural colour, which is associated with the characteristics of that food. In the processing, preservation and storage of some foods, this natural colour is destroyed or modified and in some instances, off-flavour develops. The fact that food colour is a very important factor in determining food acceptability has stimulated the grocers and manufacturers of food to develop and make the best possible food colours. These colours are frequently added to food processing or to give the preparations the natural colour as expected. The need for colours arose because some of the natural preparations such as jams, jellies, beverages tend to lose their colour during the processing as the natural colours are sensitive to heat and light or acidic or alkaline conditions. Certain mineral pigments like iron oxide, chrome yellow, manganese brown, CuSO4 were also used to colour food. This give place to synthetic dyes obtained from coal tar. Synthetic colours have the characteristics of colour intensity, colour uniformity, colour stability and lower costs. Out of the number of dyes (coal tar) available, only some are permitted for use in foods and are called esterified food colours. These are water-soluble. However, a number of coal tar dyes have been shown to be potent carcinogens therefore the use of coal tar dyes as food additives is restricted. Synthetic colours form a major group of food colours which are classified into synthetic colour dyes and mineral pigments. These synthetic colours are futher divided into acidic and basic dyes. Certain unpermitted colours such as rhodamine B, blue VRS, Orange G are being used in foods and thus are of great concern.
Natural colours consist of chlorophyll, carotenes, anthocyanins, flavones, annatto, cochineal, saffron, turmeric, cardamom, betanin, safflower, caramel etc.