Posts tagged: Food Adulteration

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 – (-)

Check out for other posts on Home Kit to Detect Food Adulteration – Part 1

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know the basic techniques to detect food adulteration at your home and tests to detect it

Home Kit to Detect Food Adulteration

Home Kit helps to detect food adulteration for detecting common adulterants in essential food commodities. The kit has brought the lab to the kitchen by simplifying the different chemical tests. Even a layperson or housewife can detect food adulteration at home to make sure that they buy good food items. The tests require only the addition of solutions and visual observation. The handy kit can be used anywhere to create public awareness and educate people about buying unadulterated foodstuff. The kit, widely hailed in the media, can be used in every household to ensure healthy and safe food.

      A few simple tests described below educate the common person about the various adulterants, the methods of detecting them with the chemistry of the tests, and the harmful effects of the particular adulterants.

FOOD ARTICLES

Coffee Powder

Adulteration – Chicory Powder (Without declaration).

Test – Sprinkle the powder on the surface of the water in a test tube.

Observation & Inference – The pure coffee powder floats while the chicory begins to sink with a reddish colour.

Principle – The chicory root has a characteristic structure, and it dissolves in cold water due to the presence of inulin. Inulin hydrolyses to give fructose, and the fructose on treatment with HCl and resorcinol (0.5%) provides a red coloured complex. Fructose with HCl gives hydroxymethyl furfural which combines with resorcinol to form a red colour.

Harmful Effects – Stomach disorder, Giddiness and joint pain (in some cases).

Food Adulteration – Tamarind seed, Date Seed Powder.

Test – Sprinkle the coffee powder on a filter paper and add the solution of Sodium carbonate.

Observation & Inference – Red colouration shows the presence of tamarind or date seed powder.

Principle – Sodium Carbonate is a mild base. On adding, colour separation takes place due to the change in pH of the solution.

Harmful Effects – Diarrhoea.

Tea

Food Adulteration – Used up tea leaves Coloured outer coats of Dhal and some Colourants.

Test – Sprinkle tea powder on a wet filter paper.

Observation & Inference – Colour separation shows the presence of adulteration.

Principle –  The coloured adulterants are banned; coal tar dyes separate on adding water as streaks on the filter paper. Genuine samples will not stain on the paper.

Harmful Effects – Liver Disorder.

Milk

Adulteration – Starch.

Test – Add a little water to the sample and boil for a few minutes. Cool and add iodine.

Observation & Inference – Blue colouration shows the presence of starch.

Principle – The blue colour is due to the formation of an inclusion complex between iodine and the amylose fraction of the starch. The linear amylose coils into a spiral, and the iodine molecule aligns within the centre of the spiral and causes light absorption that gives a blue colour.

Harmful Effects –  (-)

Food Adulteration – Water.

Test – Allow the milk to flow over a vertical polished surface.

Observation & Inference – The milk flows freely without leaving a trail when the water content is more. Pure milk will leave a trail.

Principle – (-)

Harmful Effects –  (-)

Sugar

Food Adulteration – Chalk Powder.

Test – Dissolve the sugar in a glass of water.

Observation & Inference – Chalk powder will not dissolve.

Principle – Sugar C₁₂H₂₂O₁₁ is water-soluble, white chalk powder contains Calcium carbonate and Magnesium carbonate, which are insoluble in water.

Harmful Effects – Liver Disorder.

Bura Sugar

Food Adulteration – Washing Soda.

Test – Add water and dip red litmus paper in the solution.

Observation & Inference – Blue colour shows the presence of washing soda.

Principle – Washing soda is sodium carbonate (Na₂CO₃), a base and hence gives blue colour with red litmus. Sodium carbonate a base reacts with hydrochloric acid, a reaction between acid and base, with the evolution of Carbon dioxide, which gives effervescence.

Na₂CO₃ + 2HCl —–> 2 NaCl + H₂O + CO₂

Harmful Effects – Diarrhoea, Vomiting.

Test – Take a little bura sugar in a test tube and add a few drops of a dilute solution of Hydrochloric acid (HCl).

Observation & Inference – Effervescence indicates the presence of an adulterant.

Principle – (-)

Harmful Effects –  (-)

Edible Oils

Adulteration – Argemone Oil.

Test – Treat the sample with solution Ferric chloride in the presence of a dilute solution of Hydrochloric acid. Observe through a lens.

Observation & Inference – Needle shaped brown crystals show the presence of Argemone oil.

Principle – Argemone oil contains the alkaloids sanguinarine and dihydrosanguinarine, which are toxic. These react with FeCl₃ and HCl to give brown colour. Argemone oil on treatment with Concentrated HNO₃ will provide a red colouration since these alkaloids turn red with HNO_3.

Harmful Effects –  Dropsy Gastrointe Gastrointestinal problems, Fever, Swelling of feet and legs, Oedema, Glaucoma, Respiratory distress, Cardiac arrest.

Food Adulteration – Mineral Oil.

Test – To the sample, add a little alcoholic solution potash and warm for 10 minutes. Then add water.

Observation & Inference – Turbidity shows the presence of mineral oil.

Principle – Alcoholic potash KOH will saponify the esters in oil. Still, the mineral oils which originate from Petroleum are not saponifiable by the alkaline KOH and hence on adding water gives turbidity while pure oil will saponify.

Harmful Effects –  Damage to liver, Carcinogenic effects.

Food Adulteration – Karanja Oil (Pungam Oil).

Test – To two drops of the oil, add a solution of Antimony trichloride in chloroform.

Observation & Inference – The appearance of yellow to orange colour immediately shows the presence of Karanja oil.

Principle – The non-saponifiable components of the oil react with Antimony trichloride SbCl₃/CHCl₃to form a yellow to orange coloured complex.

Harmful Effects –  Heart problems, liver damage.

Food Adulteration – Castor Oil.

Test – To the sample, add petroleum ether solution and then cool in ice.

Observation & Inference – White turbidity shows the presence of castor oil.

Principle – Castor oil contains the triglyceride component triricinolein, which gives white turbidity on treatment with petroleum ether.

Harmful Effects – Stomach problems.

Ghee & Butter

Food Adulteration – Vanaspati

Test – To a little amount of the melted ghee or butter in a test tube, add equal amounts of solution HCl, add a little sugar, and shake vigorously. Keep it standing for 5 minutes.

Observation & Inference – The appearance of a crimson red colour shows the presence of vanaspati.

Principle – This test is characteristic of sesame oil which is added to vanaspati. The phenolic substance sesamol reacts with the fructose formed by the hydrolysis of cane sugar and gives a red colour.

Harmful Effects – Liver disorder and Stomach pain.

Food Adulteration – Mashed potatoes and other starches.

Test – Add a little solution of iodine to the sample.

Observation & Inference – Blue colouration shows the presence of starch.

Principle – Iodine forms a blue coloured inclusion complex with the amylose fraction of the starch.

Harmful Effects – (-)

Dhal

Food Adulteration – Kesari Dhal and Toxic dyes.

Test – Examine the dhal with a magnifying lens.

Observation & Inference – Kesari dhal has a convoluted shape while ordinary dhal has a smooth round appearance.

Principle – (-)

Harmful Effects – Bent knees, Paralysis, Neurotoxic.

Test – To the sample, add a solution of concentrated HCl. Keep in a water bath for 15 minutes.

Observation & Inference – Pale red colour shows the presence of Kesari dhal or toxic dyes.

Principle – Kesari dhal is Lathyrus sativus, which contains beta-oxalyl amino alanine (BOAA), a toxic amino acid. On adding HCl, colour separation takes place since the toxic dyes are non-permitted colours.

Harmful Effects – Toxic dyes are Carcinogenic.

Pulses (Green Peas and Dhal)

Food Adulteration – Colour dyestuffs.

Test – Keep the sample immersed in water for about half an hour and stir.

Observation & Inference – Colour separation indicates adulteration.

Principle – The non-permitted colours like Malachite green, Congo Red is Yellow aniline dyes that show colour separation.

Harmful Effects – Stomach pain, Ulcer, Liver Problems, Tumour.

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