Kinetic and thermodynamic parameters of curcumin in edible oils with different degrees of unsaturation

Abstract

The antioxidant activity of curcumin (0.02-0.1%) was evaluated in olive, sesame, and safflower oils at 373, 383, and 393 K. The results were examined in contrast to the effects of tocopherol (0.1%) and BHT (0.02%), so that the inhibitory function of curcumin was evaluated comparatively. The activation energy of oxidation was determined for olive (82.94 kJ·mol-1), sesame (77.39 kJ·mol-1) and safflower oils (74.42 kJ·mol-1). Adding curcumin (0.1%) enhanced the activation energy by 26.26, 26.64, and 38.81% in the case of olive, safflower, and sesame oils, respectively. Based on Gibbs free energy, curcumin functioned more effectively in olive oil at 373 K (growth coefficient: 1.52%), compared to the action of the other two antioxidants, namely tocopherol (1.43%) and BHT (1.39%). The efficiency of curcumin was lower in oils which had a higher degree of polyunsaturation due to the disproportionation of the hydrogen-donating mechanism and the rate of free-radical formation in these oils.

Maximizing Curcuminoid Extraction from Curcuma aromatica Salisb. Rhizomes via Environmentally Friendly Microwave-Assisted Extraction Technique Using Full Factorial Design

“…The rhizomes of C. aromatica contain curcuminoids, including curcumin (CUR), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC), as the major chemical constituents. Among these curcuminoids, CUR is the predominant compound, and its antioxidant mechanism has been extensively studied [ 2 , 3 ]. CUR has the ability to protect biomembranes by scavenging reactive free radicals, thereby preventing peroxidative damage.…”