It is well known that Oil is ester of Glycerol and fatty acids, which can be decomposed in to their original constituent (Fatty acid and glycerol) or synthesized in to Triglycerides by Fatty acids and glycerol.
Estrification reaction is reverse of Hydrolysis process. It is carried out by reacting fatty acids with glycerol. In addition to esters, water is also a product of estrification. The reaction is reversible and proceeds to completion only if water is removed from the medium. The equilibrium between the forward reaction (Estrification) and the reverse reaction (Hydrolysis) is controlled by water content of the reaction mixture. In the presence of excess water, hydrolysis predominates, whereas under water eliminating conditions Estrification is favored.