How to Distinguish Between Pure & Adulterated Turmeric Powder
It is essential to select high-quality turmeric powder for your foods. Explore simple quality tests that you can perform in your kitchen or laboratory.
Turmeric is prized as a spice the world over. Its vibrant colour, earthy flavour, and unique aroma transform foods and drinks into sensory experiences. The zesty spice largely attributes these characteristics to the presence of curcuminoids—powerful antioxidants and anti-inflammatory compounds present in the root’s composition. Curcumin, which makes up approximately 2% – 8% of turmeric, is the most prevalent curcuminoid.
Unfortunately, as is true for so many food ingredients, rising global demand and competition have driven numerous players in the industry to undertake irresponsible actions to lower prices and increase profits. For turmeric, adulteration is one of the biggest threats impacting product quality. By cutting turmeric with other substances, such as chalk, dyes, or salts, the health values decrease, and in some cases the spice even becomes toxic.
In 2019, Stanford researchers published a study in Environmental Science & Technology unveiling the discovery of lead chromate pigment in some types of turmeric in Bangladesh. The potent neurotoxin has been banned in the food industry for decades due to its correlation with cardiovascular disease and irreversible neurological and cognitive development issues. Over the past decade, over a dozen brands were subjected to recalls as a result.
Tip: Always consult labels or inquire about turmeric's curcumin content from your suppliers and traders. High-quality turmeric will always contain a minimum of 3.75% curcumin content.
To distinguish between high-quality and low-quality turmeric, you can first take a look at its visual appearance. Pure turmeric should be bright orange to deep yellow rather than light, pale, or dull. The presence of small specks in the powder is a further potential sign of purity as they signify the likely absence of artificial dyes.
Experiencing Flavour & Aroma
Pure turmeric has a distinct and powerful gingery-floral aroma that immediately unfolds if you shake or stir it. If the scent is muted or chalky, this could be a sign that it might have been adulterated. The same holds true for the spice’s flavour. High-quality turmeric has an earthy and buttery flavour and by no means a bitter or bland aftertaste.
If turmeric is ground smoothly with occasional clumps, this is a good sign concerning quality. When turmeric is cut with other substances, such as starches, or dyed, it often becomes sandier and maintains a more unified texture throughout.
One easy way to test turmeric’s quality in your kitchen is to place a small pinch of the spice on your hand and rub it into your palm—pure turmeric will mostly stick to your skin while leaving a brightly coloured residue behind. Alternatively, add a teaspoon of turmeric to a glass of lukewarm water and wait 15 to 20 minutes for it to settle. If the water in the glass clouds up, this could indicate the presence of adulterants, whereas clear water indicates a higher purity.
Further Laboratory Testing
A series of simple laboratory tests can confirm the presence or absence of adulterants in turmeric powder. Here is a brief overview:
Metanil Yellow is a carcinogenic and toxic synthetic dye. Upon adding concentrated hydrochloric acid to turmeric powder, the sample turns pink. Upon diluting the sample with water, if the pink colour persists the presence of Metanil Yellow can be confirmed.
Chalk powder is sometimes used as a filler in cheap or low-quality turmeric powders. When concentrated hydrochloric acid is added, if the sample releases bubbles. This indicates the presence of chalk.
Starches, such as rice flour, are sometimes used to increase the volume of turmeric powder. When Iodine solution is added to the powder, a blue colour indicates the presence of starch. A further sample can then be examined under a microscope to determine which specific starch is present.
Lead, more specifically lead chromate pigment, is used to enhance turmeric’s colour when it has been cut with other substances. Upon adding a sample of turmeric to water, the presence of streaks of water-soluble colour is the first indication of potential lead chromate. In laboratories the presence of lead is tested for by adding hydrochloric acid to the sample. If the sample turns magenta, this is a positive indication for lead.
Visit our organic turmeric powder's product page to download the relevant product certificates from our website. If you wish to request additional laboratory testing, please reach out directly to our Sales Team.
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