Sugar adulteration is common especially when the prices of jaggery and sugar goes up. Common adulteration materials for sugar are: chalk powder and urea.
How do you find out?
Chalkpowder: Dissolve 10 grams of sugar in water and allow it to settle down for 15 minutes. Chalk will settle down at bottom of the cup.
Urea: Dissolve sugar in water and smell it. If it gives ammonia odor then sugar contains urea.
Washing soda in jaggery: Add few drops of HCl to jaggery and if effervescence appears then it indicates presence of soda.
Metanil yellow color in jaggery: Take 1/4 tsp of jaggery, add 3 ml of ethyl alcohol and shake it. To this slowly add 10 ml of HCl. A pink color appears indicating presence of adulteration of metanil in jaggery.
Image: Food Security officials inspecting a jaggery unit at Omalur in Salem district, www.thehindu.com