Widespread Adulteration of Turmeric
Some people may think that adulteration of turmeric occurs only in the powder. They buy the rhizome (the underground stem) believing it would end their fears of adulteration. The truth is that there are so many species of turmeric. Unless they know how to distinguish people might end up with inferior, useless, or even wild turmeric! Cunning marketers often coat it with some artificial colour to make it look more attractive.
More people buy turmeric in powder form than in any other form for obvious reasons of ease of storage and use. Unfortunately, powdered turmeric is the easiest to adulterate.
This poses the big question: how to check turmeric purity before you buy?
Test Your Turmeric: Visual, Physical and Smell Tests
Here are a few quick methods how.
These methods may turn out to be less accurate but they can give a fair idea about turmeric quality and genuineness. Some people such as those engaged in the kitchen for a long time are more adept.
The colour test
In loose powder, the one sure way to check its genuineness is to inspect its physical and visual appearance. This can be tricky sometimes. But if you buy from known and trusted sellers you are less likely to be cheated. The colour of good turmeric is a fluorescent deep orange to bright yellow. If the colour is somewhat lighter or dull yellow in shade chances are it is of lower quality or purity.
The palm test
Put a pinch of turmeric powder on the palm of your left hand. With your right thumb rub the powder for a few seconds. The good powder will stick to your palm, leaving a deep bright orange tint on it. Now tilt your left palm sideways perpendicular to the ground. Much of the powder will remain stuck on your palm. If more of it falls it may have been mixed with other ingredients like chalk.
The smell test
Good turmeric powder will have a distinct, but mild, earthy aroma and turmeric users will immediately recognize a gingery and orangey scent in it. Bad turmeric will not emit such an aroma. Rather it might have some indistinct smell that doesn’t quite give the flavour of turmeric. This may be mixed with some adulterant like talc or corn flour or with some very poor quality turmeric.
Test for foreign ingredients
At home, you can take a level teaspoon of turmeric powder and add it to a glass tumbler of lukewarm water, without stirring. Let it stand for about 15-20 minutes to settle down. If the turmeric is genuine it will settle at the bottom and the water will be clear. But if there are foreign ingredients the water will cloud.
Chemical and Microscopic Tests
These will involve using water, acids and the microscope to detect changes and textures determining the presence of adulterants.
Test for Metanil Yellow
Metanil yellow, a synthetic dye is one of the commonest adulterants of turmeric powder. To test for its presence take a pinch of turmeric powder in a test tube and add a few drops of concentrated hydrochloric acid to it. The colour will turn pink. If on adding water the pink colour disappears it means there is Metanil Yellow. It is carcinogenic and toxic.
Test for Yellow Lead Salts
Take a pinch of turmeric powder in a test tube. Add a few drops of concentrated hydrochloric acid to it. If the colour turns magenta it shows adulteration with yellow oxides of lead. It can cause cancer.
Test for Chalk Powder
Take a teaspoon of turmeric powder in a test tube or beaker. Add a few drops of water followed by a few drops of concentrated hydrochloric acid. If there is effervescence it means chalk powder is present. It can cause indigestion.
Test for Aniline Dyes
Take a teaspoon of turmeric powder and add a few drops of water to it. Then add 5 ml of methylated spirit. If the yellow colour disappears it means aniline dye is present. Aniline is an oily liquid used for manufacturing aniline dyes which can cause cancer.
Test for Starch
Starches can be of rice, maize, tapioca or cassava. To test the presence of starch a sample of turmeric needs to be placed under a microscope. Turmeric particles will appear as yellow, angular and bigger. Starch particles are pale white, rounded and smaller. Starches can cause stomach upset.
Examining Good Quality Rhizome
Rhizome comparison Test – This involves knowing the actual rhizomes species to determine the quality of turmeric
To know the turmeric rhizome of good quality requires some study of different varieties of turmeric. Consult growers or those with experience about the plant. For example, the following pictures are of
- The famous Lakadong turmeric of Meghalaya, the world’s best turmeric having the highest curcumin content and refreshing scent and taste
- The inferior quality or Lakachein turmeric, also from Meghalaya, having less palatable, bitter taste.
How to Avoid Adulterated Products?
Buy only from genuine, licensed and certified companies. That way you can be certain you will get quality. Or buy from a source you know very well. Otherwise, it is better to purchase only sealed products whose packaging display all the mandatory information. Every country has food laws manufacturers must adhere to. In India, the FSSAI (Food Safety and Standards Act of India) requires its logo to be printed on the packet, besides other information. Some manufacturers have additional certifications as well such as HACCP and ISO, which indicates more credibility.