Elementary plant Biochemistry and Biotechnology (2+1)

Properties of fat

• Fats are greasy to touch and leave an oily impression on paper. They are insoluble in water and soluble in organic solvents. Pure triacylglycerols are tasteless, odourless, colourless and neutral in reaction. They have lesser specific gravity (density) than water and therefore float in water. Though fats are insoluble in water, they can be broken down into minute dropletsand dispersed in water. This is called emulsification.


• A satisfactory emulsion is one highly stable and contains very minute droplets with diameter less than 0.5 μm. Examples of naturally occurring emulsions are milk and yolk of egg. But they are not mere fat droplets in water. They contain hydrophilic colloidal particles such as proteins, carbohydrates and phospholipids which act as stabilizing agents. Emulsification greatly increases the surface area of the fat and this is an essential requisite for digestion of fat in the intestine.