Evaluation of oxidative stability in hazelnut oil treated with several antioxidants: Kinetics and thermodynamics studies

Rancimat accelerated oxidation method was applied in four temperature values (110, 120, 130 and 140 degrees C) for the evaluation of hazelnut oil kinetics, thermodynamics and quality parameters. Depending on Arrhenius model and activated complex theory, rate constant (k), energy for activation (E-a), enthalpy (Delta H degrees), entropy (Delta S degrees) and Gibbs free energy (Delta G degrees) of hazelnut oil oxidation were found. Oxidation process in both treated and untreated products was an endothermic, non-spontaneous and endergonic process. The quality indicators of treated and untreated oil samples were also compared depending on phenolic and carotenoid contents, antioxidant activity, peroxide value and induction time. Gallic acid enhanced the shelf-life of the relevant product nearly 3 times over the untreated sample, while total biophenols increased by 77%.