Q. Estimation of synthetic food colours in foods?

Food colours in various products need to be isolated, identified and then quantitatively measured for their limits. Estimation techniques for water soluble and oil soluble colours vary. One can use the wool dyeing method for isolation of acidic colours and can also use chromatographic techniques for their identification and measurement.

To identify them, we must study the colour reactions of these water soluble, acidic dyes which are characteristic to each colour and thus can be used as conformatory tests. The reactions of various colours with different chemical medium are given in Table.