date:Sep 07, 2012
the presence of the pink colour indicates the presence of metanil yellow.
Turmeric (a colour used for the golden appearance)
(i) A small amount of sella rice is taken in a test tube, some water is added and it is shaken. If, upon dipping boric acid paper (filter paper dipped in boric acid solution), it turns pink, turmeric is present
(ii) Some rice is taken and a small amount of soaked lime is sprinkled on it for a while. If turmeric is present, the grains will turn red