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Detection of adulterant in Dal
Introduction
Food is essential to provide nutritional support for the human body. Food supplies fuel for
our body by providing it with the many nutrients that are essential for good health. Ancient
India produced food that was more than the demand and people ate fresh food daily.
Due to the population explosion in modern India, the demand for food increased and traders
started mixing cheaper substances with the food to increase the amount of food available
and in some cases, to increase their profits when selling the food. These cheaper or undesirable
substances added to the food are called adulterants.
Food adulteration can also involve adding colourants to supposedly make the food more
attractive or products that help the food stay fresher or keep it from spoiling. However,
some of these products have been shown to be harmful and need to be avoided when purchasing
food. In the process of food adulteration, poisons may be added to the food or valuable
nutrients removed. Food adulteration may happen intentionally or unintentionally.
Metanil yellow is a principal non-permitted food colour used extensively in India. The
effects of long-term consumption of metanil yellow on the developing and adult brain will
cause neurotoxicity and metanil yellow also is cancer causing. Metanil yellow is used
with dal as an adulterant for colouring. When adding a few drops of HCl to a test sample,
if the solution turns pink in colour, this indicates the presence of metanil yellow in
the dal.
To do experiment we require:
Arhar dal, distilled water, hydrochloric acid, test tube with stand, watch glass and spatula.
Procedure: Take a clean test tube from the test tube
rack. Take some dal in to a test tube using a spatula.
Add some distilled water to the test tube that contains dal.
Shake the solution properly to mix compounds. Allow it to stand for 30 minutes.
Take concentrated hydrochloric acid using a dropper.
Add a few drops of concentrated hydrochloric acid into the test solution.
Indication of pink colour shows the presence of adulterant metanil yellow in the test material.
Precaution: Use conc. Hydrochloric acid judiciously.