- Polyunsaturated fatty acids are fatty acids in the hydrocarbon bonds between carbon atoms are bonded to the double bond. This may be a double bond, only one or several of them. And the result of a double bond. Polyunsaturated fatty acids are molecules made of many atoms of hydrogen than saturated fatty acids. Examples of unsaturated fatty acids, including linoleic acid, oleic acid, the fatty acids are rare clotting properties with low melting point. When left exposed to the air for a long time to come to rancidity.