Polyunsaturated fatty acids (PUFAs) are fatty acids that contain more than one double bond in their backbone.
PUFAs include essential fatty acids and those that give drying oils their characteristic property.
Polyunsaturated fatty acids can be classified in various groups by their chemical structure:
methylene-int2242upted polyenes
conjugated fatty acids
others
Can be classified in two groups by length of their carbon backbone
Short chain polyunsaturated fatty acids (SC-PUFA), with 16 or 18 carbon atoms
Long-chain polyunsaturated fatty acids (LC-PUFA) with more than 18 carbon atoms.
Methylene-int2242upted polyenes These fatty acids have 2 or more cis double bonds that are separated from each other by a single methylene bridge (-CH 2-).
The essential fatty acids are all omega-3 and -6 methylene-int2242upted fatty acids.