Chemistry Project – Detection of adultration in food

 

EXPERIMENT 1                                                                                                               Download Pdf

 

AIM: To detect the presence of adulterants in fat, oil and butter.

REQUIREMENTS: Test-tube, acetic anhydride, conc. H2SO4, acetic acid, conc. HNO3.

PROCEDURE:

Common adulterants present in ghee and oil are paraffin wax, hydrocarbons, dyes and argemone oil. These are detected as follows:

(i )  Adulteration of paraffin wax and hydrocarbon in vegetable ghee-

Heat small amount of vegetable ghee with acetic anhydride. Droplets of oil floating on the surface of unused acetic anhydride indicates the presence of wax or hydrocarbons.

(ii) Adulteration of dyes in fat-

Heat 1mL of fat with a mixture of 1mL of conc. sulphuric acid and 4mL of acetic acid. Appearance of pink or red colour indicates presence of dye in fat.

(iii)  Adulteration of argemone oil in edible oils-

To small amount of oil in a test-tube, add few drops of conc. HNO3 and shake. Appearance of red colour in the acid layer indicates presence of argemone oil.

 

EXPERIMENT 2

 

AIM:  To detect the presence of adulterants in sugar.

REQUIREMENTS: Test-tubes, dil. HCl.

PROCEDURE:

Sugar is usually contaminated with washing soda and other insoluble substances which are detected as follows :

(i) Adulteration of various insoluble substances in sugar

Take small amount of sugar in a test-tube and shake it with little water. Pure sugar dissolves in water but insoluble impurities do not dissolve.

(ii) Adulteration of chalk powder, washing soda in sugar

To small amount of sugar in a test-tube, add few drops of dil. HCl. Brisk effervescence of CO2 shows the presence of chalk powder or washing soda in the given sample of sugar.
To detect the presence of adulterants in samples of chilli powder, turmeric powder.

 

EXPERIMENT 3

 

AIM: To detect the presence of adulterants in chilli powder, turmeric powder and pepper.

REQUIREMENTS: Test-tubes, conc. HCl, dil. HNO3, KI solution

PROCEDURE:

Common adulterants present in chilli powder, turmeric powder and pepper are red coloured lead salts, yellow lead salts and dried papaya seeds respectively.

They are detected as follows:

(i) Adulteration of red lead salts in chilli powder

To a sample of chilli powder, add dil. HNO3. Filter the solution and add 2 drops of potassium iodide solution to the filtrate. Yellow ppt. indicates the presence of lead salts in chilli powder.

(ii) Adulteration of yellow lead salts to turmeric powder

To a sample of turmeric powder add conc. HCl. Appearance of magenta colour shows the presence of yellow oxides of lead in turmeric powder.

(iii) Adulteration of brick powder in red chilli powder

Add small amount of given red chilli powder in beaker containing water. Brick powder settles at the bottom while pure chilli powder floats over water.

(iv)  Adulteration of dried papaya seeds in pepper

Add small amount of sample of pepper to a beaker containing water and stir with a glass rod. Dried papaya seeds being lighter float over water while pure pepper settles at the bottom.

 

OBSERVATION TABLE

 

EXPERIMENT PROCEDURE OBSERVATION
Adulteration of paraffin wax and hydrocarbon in vegetable ghee Heat small amount of vegetable ghee with acetic anhydride. Droplets of oil floating on the surface of unused acetic anhydride indicate the presence of wax or hydrocarbon. Appearance of oil floating on the surface.
Adulteration of dyes in fat

 

Heat 1mL of fat with a mixture of 1mL of conc. H2SO4 and 4mL of acetic acid.

 

Appearance of pink colour.
Adulteration of argemone oil in edible oils

 

To small amount of oil in a test tube, add few drops of conc.HNO3 & shake.

 

No red colour Observed.
Adulteration of various insoluble substances in sugar Take small amount of sugar in a test tube and shake it with little water. Pure sugar dissolves in water but insoluble impurities do not dissolve.
Adulteration of chalk powder, washing soda in sugar To small amount of sugar in a test tube, add a few drops of dil. HCl. No brisk effervescence observed.
Adulteration of yellow lead salts to turmeric powder To sample of turmeric powder, add conc. HCl. Appearance of magenta colour.
Adulteration of red lead salts in chilli powder To a sample of chilli powder,add dil. HNO3. Filter the solution and add 2 drops of KI solution to the filtrate. No yellow ppt.
Adulteration of brick powder in chilli powder Add small amount of given red chilli powder in a beaker containing water. Brick powder settles at the bottom while pure chilli powder floats over water.
Adulteration of dried papaya seeds in Pepper Add small amount of sample of pepper to beaker containing water and stir with a glass rod. Dried papaya seeds being lighter float over water while pure pepper settles

 

CONCLUSION        

Selection of wholesome and non-adulterated food is essential for daily life to make sure that such foods do not cause any health hazard. It is not possible to ensure wholesome food only on visual examination when the toxic contaminants are present in ppm level. However, visual examination of the food before purchase makes sure to ensure absence of insects, visual fungus, foreign matters, etc. Therefore, due care taken by the consumer at the time of purchase of food after thoroughly examining can be of great help. Secondly, label declaration on packed food is very important for knowing the ingredients and nutritional value. It also helps in checking the freshness of the food and the period of best before use. The consumer should avoid taking food from an unhygienic place and food being prepared under unhygienic conditions. Such types of food may cause various diseases. Consumption of cut fruits being sold in unhygienic conditions should be avoided. It is always better to buy certified food from reputed shop.

 

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