عنوان مقاله [English]
Oxidative stability of oils and fats influenced by various factors such as oxygen, light, heat, metal ions and enzymes. The use of synthetic antioxidants to delay the oxidation deterioration, due to the possibility of toxicity and carcinogenicity, has been under questioned. The aim of this study was to optimize the extraction conditions of Ajowan seed and evaluate their antioxidant properties and extracted phenolic compounds from it. In this study acetone extracts of Ajowan seed under different concentration of acetone (0, 50 and 100%), extraction time (0, 12 and 24 hours) and different temperatures (20, 40, 60 °C) were prepared. After different analysis of the obtained extracts, the optimum extraction conditions were determined by response surface methods and extraction was performed at the optimum condition. Then different concentrations (0.2, 0.4 and 0.6%) of optimum extracts were prepared and added to the non- containing antioxidant soybean oil. Also an oil sample without antioxidant and an oil sample containing 200 ppm BHT were prepared. All treatments kept under accelerated oxidation condition (90 °C for 5 days). Different analysis, including acidic value, peroxide value and thiobarbituric acid (TBA) were performed on each treatment in every day. Data analysis showed that addition of water to the solvents increased phenolic compounds extraction and antioxidant activity, due to increased solvent polarity. According to the results of the thermal stability of studied oils under accelerated oxidation condition (90 0C for 5 days), the best results were related to synthetic antioxidant BHT and higher concentrations of ethanol and acetone extracts. Oil stability affected by phenolic and antioxidant compounds which exist in Ajowan seeds.