Oils & Fats Adulteration - Chapter – 4 #

4.1.Check the presence of Mineral oils like kerosene oil, Paraffin oil and other petroleum product in eatable and Natural Hair oils. 

Test Method – 1:

Principle: 

The presence of Mineral oil is indicated by the development of turbidity when hot water is

added to a freshly made alcoholic solution of the soap formed by the oil.

·         Take 2 ml of oil sample and add an equal quality of N/2 Alcoholic Potash.

·         Heat in boiling water bath (dip in boiling water) for about 15 minutes and add 10 ml of water. Any turbidity shows the presence of Mineral oil more than 1 % w/w.

Test Method – 2: Holde’s Test

·         Take 25 ml of the alcoholic KOH solution in conical flask and add 1 ml of the sample of oil to be tested.

·         Boil on a water bath using an air or water cooled condenser till the solution becomes clear and no oily drops are found on the sides of the flask.

·         Take out the flask from the water bath, transfer the contents to a wide mouthed warm test tube and carefully add 25 ml of boiling distilled water along the sides of the test tube.

·         Keep on shaking the tube lightly from side to side during the addition.

·         The turbidity indicates presence of Mineral oil, the depth of turbidity depends on the percentage of mineral oil present.

Note: This method is not applicable on high content un-saponifiable value and below 1% content of Mineral oil.

Reference: A.O.A.C 17^th edition 2000, official method 945.102

4.2. Adulteration of Castor oil in Edible oils 

Genuine Products:

·         Olive oil

·         Mustard oil

·         Sunflower oil

·         Soyabean oil

Adulterant:

Castor oil – It is common adulterant of Olive oil, sunflower oil and soyabean oil. Castor Oil is a very pale yellow liquid that is extracted from castor seeds (Ricinus Communis). it has a strong and rather unpleasant taste.

Test Method:

• In a clean, dry test tube take about 1 ml of the oil or melted fat and add 10 ml of acidified petroleum ether.
• Shake vigorously for 2 minutes and add one drop of the molybdate reagent. Instantaneous development of white turbidity indicates the likely presence of castor oil.

  

  CASTOR OIL IN EATABLE OILS

 Reagents Preparation for test Method-

• Sulphuric acid-molybdate reagent - In 100 ml of concentrated sulphuric acid dissolve 1.25 g of ammonium molybdate.
• Acidified petroleum ether - Add 2 ml of concentrated hydrochloric acid to 100 ml of petroleum ether (boiling range 40 to 60 degree or 60 to 80 ̊C).

• Reference:

a.      IS : 548 (Part II) - 1976

b.      I.S.I. Handbook of Food Analysis (Part XIII) –1984 Modified test for presence of Castor oil, page 91

Heal Effect: Pregnant and lactating women and people with intestinal blockage, acute inflammatory intestinal disease, appendicitis, or abdominal pain should not take Castor Oil. Over dosage of Castor Oil may result in diarrhea, nausea, vomiting, abdominal pain or cramping.