Effect of Phycocyanin and Butylated Hydroxytoluene on the Oxidative Stability of Safflower Oil: A Comprehensive Kinetic Investigation

Safflower includes both saturated and unsaturated fatty acids especially high levels of polyunsaturated fatty acid (PUFA). The addition of antioxidants during oil processing is one of the most effective methods. The aim of this research was to evaluate the oxidative stability of safflower oil supplemented with phycocyanin (PC) (200, 300, and 400 ppm), or butylated hydroxytoluene (BHT) (200 ppm), at 80, 90, and 100°C during the storage time. Oxidative stability of oil was measured through the assay of primary and secondary oxidation products: Peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were evaluated, respectively. Results showed that the addition of PC at 300 and 400 ppm caused the lowest peroxide levels. In addition, the oxidation reactions of this oil followed a first-order kinetic model for PV and TBARS. The amounts of PV and TBARS were dependent on the storage temperature; according to the Arrhenius equation, the activation energy (E_a) of the samples that contain 300 and 400 ppm PC decreased in all the tested temperatures compared to control. Results of the oxidative stability indicated that PC may have superior antioxidant properties than BHT and can potentially inhibit the oil oxidation. The sample containing 300 ppm PC demonstrated heightened efficacy in suppressing primary oxidation. Moreover, the results of sensory evaluation test showed that the 300 ppm PC sample received the highest rating for overall quality, which confirm that 300 ppm PC sample could be the best sample to decrease the oxidative stability in safflower oil.