To study the common food adulterants in honey, turmeric powder, Chilli powder and pepper
Aim
To study the common food adulterants in honey, turmeric powder, chilli powder and pepper.
Apparatus and Chemicals Required
Test tubes, test tube stand, glass rod, beaker, dil. HCl, dil. H2SO4, ether, alcoholic solution of diphenyl carbazide.
Principle
Honey is immiscible with water. Dilute HCI precipitate with potassium iodide. Brick powder gets settled at produces CO2 with washing soda. Lead salt gives yellow the bottom of water. Papaya seeds float over water.
Procedure
- 2 tea spoons of vinegar with some water is added to one tea spoon of honey. Formation of solution shows adulteration.
- Adulteration of red lead salt in Chilli Powder is detected by adding dil. HNO3 to it in a test tube. The solution filtrate. Yellow precipitate confirms the presence of red lead is filtered and two drops of potassium iodide are added to the salt in chilli powder.
- To Detect the adulteration of brick powder in chilli powder A small amount of chilli powder is boiled with 15 ml distilled water in boiling tube. Setting of red powder at the bottom confirms the presence of brick powder in chilli powder.
- To detect the presence of red dye in chilli powder- To about 2 g chilli powder, 5 ml ether is added in a test tube. On shaking the test tube appearance of pink colour confirms the presence of red dye in chilli powder.
- To detect the presence of papaya seeds in black pepper-100 ml water is taken in a 250 ml beaker. Few seeds of black pepper are added to this water. Papaya seeds float on the water while black pepper gets settled down.
- To detect the adulteration of lead chromate in turmeric powder-About 1 g turmeric powder is boiled with 10 ml dil. H2SO4 in a boiling tube. After cooling it is filtered and 2% alcoholic solution of diphenyl carbazide is added to the filtrate. Appearance of pink or red colour confirms the presence of lead chromate in turmeric powder.
- To detect the adulteration of yellow chalk powder in turmeric powder-About 1 g turmeric powder is taken in a test tube. To it 1 ml dil. HCl is added. Evolution of colourless, odourless gas confirms the presence of yellow chalk powder in turmeric powder.
- To detect the adulteration of metanil yellow dye in of turmeric powder. Appearance of violet colour which persists turmeric powder-Few dropes of HCI are added in about 1 g even after dilution confirms the presence of metanil yellow dye in turmeric powder.
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Image Credits: Freepik
