Definition of lipids and Explanation.
- Fats and oils: These lipids give long-chain fatty acids and glycerol upon hydrolysis.
- Waxes: These lipids give long-chain fatty acid and long-chain alcohols upon hydrolysis.
Characteristics of lipids:
They are soluble in non-polar solvents like ether, chloroform and benzene.
They are Po-building blocks of:
- Fatty acids
Fats and oils are widely distributed in nature and have great nutritional values. They provide energy to the animal body for maintaining optimum body temperature.
- Drying oils
- Printing inks
Classification of lipids.
- Glycerol phospholipids.
Derived associated lipids:
- Diglycerides fatty acids.
- Vitamin D
Importance of lipids.
- They are a good source of energy and make the food more palatable.
- They exert an insulating effect on the nervous tissues.
- They are good energy reservoirs in the body.
- Lipids are an integral part of cell protoplasm and cell membranes.
- Some lipids act as precursors of very important physiological compounds. For example; cholesterol is the precursor of steroid hormones.
Physical Properties of lipids.
- Oils and fats may be either liquids or non-crystalline solids at room temperature.
- Fats and oils in the pure states are colourless, odourless and tasteless.
- The colour of fat arises due to foreign substances. For example, the yellow colour of the butter is due to the presence of keratin.
- They are lighter than water.
- They are insoluble in water.
- They are readily soluble in organic solvents like diethyl ether, carbon disulphides, acetone, benzene, chloroform and carbon tetrachloride.
- They form emulsions when they are agitated with water in the presence of soap or another emulsifier.
- Fats and oils are poor conductor of heat and electricity and serve as an excellent insulator for the animal body.