Human Nutrition 3(3+0)

Lesson 15 : Lipids

Properties of fats

1. Solubility: Fats are soluble in organic solvents such as ethyl ether, petroleum ether, acetone and benzene. The quantity of fat present in food materials is usually determined by extraction with ethyl ether or petroleum ether.

2. Saponification Value (Saponification number): The saponification value is defined as the number of milligrams of potassium hydroxide required to saponify 1 g. of fat or oil.

3. Iodine Value (Iodine number): It is a measure of the extent of unsaturated fatty acids present in fats and oils. It is defined as the number of grams of iodine absorbed by 100g of fat.

4. Reichert-Meissl Value: This is defined as the number of milliliters of 0.1 N alkali (sodium or potassium hydroxide) required to neutralize the steam volatile water soluble fatty acids present in 5 g. sample of fat. The test determines the amount of butyric acid and caproic acid which are readily soluble in water and a part of caprylic acid which is slightly soluble in water.

5. Thiocyanogen Value: The thiocyanogen number is the amount of thiocyanogen absorbed by 100 grams of fat or oil.