know the basic techniques to detect food adulteration at your home and tests to detect it
Home Kit to Detect Food Adulteration
Turmeric Powder
Adulteration – Yellow Aniline Dyes
Test – Shake a little Turmeric powder (Suspended in Water) with a solution of Rectified spirit.
Observation & Inference – The solution turns yellow immediately.
Principle – The Yellow aniline dyes separate on adding rectified spirit.
Harmful Effects – Carcinogenic.
Sweets, Juices, Jams
Adulteration – Non-permitted coal tar dye (Metanil Yellow).
Test – To the sample add hot water and to the separated colouring matter, adds a few drops of HCl.
Observation & Inference – Pinkish Red colour shows the presence of Metanil yellow.
Principle – On adding HCl, the structure of Metanil yellow gives a pink colour at low pH.
Harmful Effects – Metanil yellow is toxic and Carcinogenic.
Wheat & other food grains
Adulteration – Ergot (A Fungus containing a poisonous substance).
Test –To the sample add common salt solution and shake.
Observation & Inference – The impurity ergot floats on top while the pure food grains settle at the bottom.
Principle – (-)
Harmful Effects – Poisonous
Black Pepper
Adulteration – Papaya Seeds.
Test – Smell Pepper, Examine with a magnifying lens.
Observation & Inference – Papaya seeds have a repulsive flavour; Examine with a magnifying lens.
Principle – (-)
Harmful Effects – Stomach, Liver problems.
Adulteration – Rotten pepper and light berries.
Test – Add a little solution of Rectified spirit to the sample.
Observation & Inference – Rotten pepper, Papaya seeds and light berries float.
Principle – (-)
Harmful Effects – Stomach, Liver problems.
Chilli Powder
Adulteration – Brick Powder.
Test – Add water to the powder and shake.
Observation & Inference – The brick powder settles down.
Principle – Due to the heaviness, brick powder settles down. The brick powder contains calcium salts which give brick red flame.
Harmful Effects – Stomach Problems.
Adulteration – Brick Powder.
Test – To a little powder add concentrated HCl introduce as paste into flame through the backside of a matchstick.
Observation & Inference – The brick red flame colour is due to the presence of calcium salts in brick powder.
Principle – Due to the heaviness, brick powder settles down. The brick powder contains calcium salts which give brick red flame.
Harmful Effects – Stomach Problems.
Adulteration – Artificial Colours.
Test – Sprinkle the chilli powder on a glass of water.
Observation & Inference – Artificial colourants descend in coloured streaks.
Principle – (-)
Harmful Effects – Toxic.
Asafoetida
Adulteration – Foreign resins galbanum, Colophony resin.
Test – Powder a gram of Asafoetida and shake it with a solution of Rectified spirit. Filter the extract and to 5 mL of it, add the solution of FeCl3.
Observation & Inference – Olive Green colour shows the presence of foreign resins.
Principle – Colophony is a resin obtained as a residue after the distillation of Turpentine oil. This forms a coloured complex when shaken with Rectified spirit and Ferric Chloride.
Harmful Effects – Allergy, Dysentery.
Test – Burn on a spoon (Like Camphor).
Observation & Inference – Burns like camphor shows a pure sample.
Principle – Pure Asafoetida burns quickly like aromatic camphor.
Harmful Effects – (-)
Honey
Adulteration – Sugar plus Water.
Test – A cotton wick dipped in honey is burnt.
Observation & Inference – If adulterated with water, the honey will not burn or burn with a cracking sound.
Principle – Due to the presence of water, the wick does not burn or form a cracking sound.
Harmful Effects – (-)
Adulteration – Invert Sugar
Test – Add Resorcinol and HCl.
Observation & Inference – The red colour is obtained.
Principle – When honey is adulterated with invert sugar (Glucose and Fructose) on adding Resorcinol and HCl, red colour is obtained.
Harmful Effects – (-)
Cloves
Adulteration – Cloves from which volatile oil has been extracted.
Test – Examine with a magnifying lens.
Observation & Inference – Can be identified by the small size and shrunken appearance. The adulterated cloves are less pungent.
Principle – (-)
Harmful Effects – (-)
Jaggery
Adulteration – Washing Soda.
Test – Add a few drops of a solution of HCl.
Observation & Inference – Effervescence shows the presence of washing soda.
Principle – Washing soda, a base reacts with hydrochloric acid and liberates CO2 which gives effervescence.
Harmful Effects – Diarrhoea, Vomiting.
Adulteration – Chalk Powder.
Test – Dissolve a little sample in water in a test tube.
Observation & Inference – Chalk powder settles down.
Principle – (-)
Harmful Effects – (-)
Test – Add a few drops of a solution of concentrated HCl.
Observation & Inference – Effervescence indicates the presence of an adulterant.
Principle – Chalk powder contains carbonates of magnesium and calcium. These carbonates react with HCl and liberate CO2 with effervescence.
CaCo3 + 2HCl —> CaCl2 + H2O + CO2
Harmful Effects – Liver Disorder.
Common Salt
Adulteration – Chalk Powder or White powdered stone.
Test – Dissolve a little sample in water.
Observation & Inference – The solution turns white indicating the presence of chalk and other impurities settle down.
Principle – Chalk powder contains carbonates of magnesium and calcium which are insoluble in water and hence the solution turns white.
Harmful Effects – Stomach Disorder.
Mustard Seeds
Adulteration – Argemone Seeds.
Test – Examine with a magnifying lens.
Observation & Inference – Mustard seeds have a smooth surface while the argemone seeds have a rough surface and are blacker in colour.
Principle – (-)
Harmful Effects – Oedema (Dropsy).
Silver Leaves
Adulteration – Aluminium Leaves.
Test – Burn the leaves in flame.
Observation & Inference – Pure silver leaves burn away completely leaving glistening balls while aluminium leaves are reduced to grey ash.
Principle – (-)
Harmful Effects – (-)
Supari
Adulteration – Colours and Saccharin.
Test – Add water to the sample.
Observation & Inference – Colour dissolves in water. Saccharin gives the characteristic sweet taste.
Principle – (-)
Harmful Effects – (-)
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