Oils and fats are unstable compounds and are not resistant to the deterioration processes of oxidation, hydrolysis and polymerization that occur during heating. Lipid oxidation is a major cause of deterioration during shelf life and in the process of heating vegetable oils. Oxidation may cause sensory and chemical changes, as well as a reduction in nutritional value. Moreover, it results in the appearance of dimers, polymers and cyclic monomers that might be potentially toxic