Effects of Celery Extracts on the Oxidative Stability of Canola Oil Under Thermal Condition.

The effect of extraction methods (ultrasound and supercritical fluid) and solvents (ethanol, ethanol/water (50:50) and water) on the phenolic compounds and antioxidant activities of celery ( A pium graveolens) extracts was evaluated to determine the most suitable extraction method for protective effects on stabilizing canola oil ( CAO) during thermal condition (24 h at 180 C). Ultrasound ethanol/water extract was found to have the highest phenols compounds (438.75 mg gallic acid equivalents/g sample) and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [ DPPH] and oxidative stability index 98.71 % and 7.1 h, respectively). Then, this extract was added to CAO. Peroxide value, carbonyl value, polar compound, acid value conjugated dienes value and color index were taken as parameters for evaluation of stabilization efficacy of the celery extract. Results from different parameters were in agreement with each other, suggesting higher efficiency of celery extracts followed by tertiary butylhydroquinone and control treated (without additives), respectively. Practical Applications Lipid peroxidation is responsible for the quality deterioration of vegetable oil, fats and other food systems. Thus, the use of antioxidants to minimize the oxidation of lipids in food materials is extensively practiced. Recently natural antioxidants have gained increased interest because natural food ingredients are safer than synthetic ones. The result of this study showed that celery extracts have antioxidant activity and it can replace synthetic antioxidant tertiary butylhydroquinone in canola oil. [ABSTRACT FROM AUTHOR]