THEORETICAL APPROACH OF DFT B3LYP/6-31G (d, p) ON EVALUATING THE PERFORMANCE OF tert-BUTYLHYDROQUINONE AND FREE FATTY ACIDS IN INHIBITING THE OXIDATION OF PALM OLEIN

The effects of adding palmitic acid (PA) and linoleic acid (LA) on the performance of tert-Butylhydroquinone (TBHQ), in inhibiting the autoxidation of palm olein was studied.These fatty acids were employed to test their effectiveness on antioxidant performance, experimentally and theoretically.In experimental studies, palm olein added with fatty acids at four different concentrations in the presence or in the absence of TBHQ were heated in the oven at 60°C for 15 days and collected after 0, 1, 3, 6, 10 and 15 days for peroxide values analysis.In the theoretical study, a quantum mechanical at the theoretical level of DFT B3LYP/ 6-31G (d,p) was used in optimising the molecular structures of single species and complexes, and then tested for physical parameters (dipole moment, stabilisation energy, and bond indexes).It was found in the presence of TBHQ, synergistic behaviour was found between fatty acid and antioxidants.The addition of PA, which is the same as the main component of palm olein, significantly decreased oxidation and peroxide formation, thus gave less effect to the degradation of triacylglycerides.Based on the theoretical calculations, the interaction energy is shown as the major contributor to the performance of the antioxidant.