Chemistry of Dietary FAT
It was very interesting as well as challenging to gather information on Chemistry of FAT.
- Fats are large molecules made up of elements - Carbon, Hydrogen, Oxygen
- Their hydrogen to Oxygen ratio is higher than 2:1
- Due to such a molecular arrangement, fat contains more energy storing carbon hydrogen bonds than carbohydrate
- Fats are non polar, insoluble molecules
- So they are perfect storage molecules
- Thus our body converts all the excess sugar taken through' diet into fat
- The Basic structure of FAT is as follows:
Oils and fats are made up of more than one component.
1. Glycerol 2. Fatty acids
Glycerol is a 3 carbon molecule each with a hydroxyl group (-OH). This 3 carbon molecule forms the backbone of fat molecule.
Fatty acids are long chains with only carbon and hydrogen in a chain and at the end there will be another group, carboxyl group ( -COOH)
- 3 fatty acids get attached to Glycerol and then they are called triglycerides
- Most dietary fat is in the form of triglycerides
- Fatty acids found in animal triglycerides are saturated ones
- Fatty acids found in plant triglycerides are unsaturated ones ( exception - tropical oils)
- When a fatty acid is with single bond between its carbon atoms.
It has maximum number of hydrogen atoms and
thus forms a saturated triglyceride when attached to glycerol. e.g.palmitic acid
- When a fatty acid is with one or more than one double bond and fewer hydrogen atoms attached to carbon chain. This is an example of monounsaturated and polyunsaturated fatty acid, respectively. When it attaches to Glycerol it forms unsaturated triglyceride. e.g. linolenic acid with 3 double bonds and fewer hydrogen atoms attached to carbon chain
- The double bonds between carbon atoms, in an unsaturated fat keeps the fat in a liquid form at room temperature. E.g. oils Where as saturated fats stays solid at room temperature e.g. butter, animal fat
The other kinds of lipid are:
- Phospholipids: They are similar to fat. The difference is another group, Phosphate (PO4), replaces one of the fatty acid side chain.
- Waxes: They provide a waterproof coat on the skin of leaves, fruits and on the outer coating of insects. They are large lipid molecules
- Steroids: These are fat soluble compounds. E.g. harmones like estrogen and cholesterol. ( Cholesterol has an important role in cell membrane. It helps maintaining fluidity.)
- Terpenes: These are related to steroids but slightly smaller molecules. These include Vitamins A,E and K.