Essential fatty acids are fatty acids that are required in the human diet. This means they cannot be synthesized by the body and must be obtained from food.
Industrially, fatty acids are produced by the hydrolysis of the ester linkages in a fat or biological oil, with the removal of glycerine.
Saturated fatty acids are of the form
O HOC-R , that is, HOOC-R
where
R = CH2(CH2)nCH3
Unsaturated fatty acids are of similar form, except that one or more alkene functional groups exist along the chain, substituting singly-bonded
-CH2-CH2-
portions of the chain with doubly-bonded
-CH=CH-
portions. In most of these, each double bond has 3n carbon atoms after it, for some n, and are all cis bonds; they are called the omega-3 double bond, omega-6, omega-9, and so on.
Several fatty acid molecules. Erucic and oleic are omega-9, arachidonic and linoleic are omega-6 fatty acids[?], linolenic is an omega-3 fatty acid, and arachidic, stearic, and palmitic are saturated.