Oxidation kinetics of hazelnut oil treated with ozone

The present study investigates the oxidation kinetics of hazelnut oil ozonated in different treatment periods (1, 5, 60 and 180 min). The kinetic rate constant ( k ) was taken as the inverse of oxidation onset time (T o ) observing a linear relationship from the plot of lnTo to isothermal temperatures (373, 383, 393, and 403 K) carried out at differential scanning calorimetry. Kinetic parameters, activation energy (E a ), activation enthalpy (Δ H ‡ ) and entropy (Δ S ‡ ) were calculated based on the Arrhenius equation and activated complex theory. k values showed an exponential rise with the increase of ozone treatment time. The increase in k correlated well with the increase in the peroxide and free fatty acid values of all samples. E a and ∆ H ‡ of the ozone treated oils showed a reducing trend and reflected an increased oxidation sensitivity after ozone treatment. Consistently, an increase in ∆ S ‡ indicated a faster oxidation reaction with an increase in ozone exposure time. However, no significant difference was observed in k , E a , Δ H ‡ , Δ S ‡ (p < 0.05) as a function of storage period, after the hazelnut oil was treated with ozone for 1 min.