Extraction of Phenolic Compounds and Tocopherols from Ferula Persica and Evaluating the Effect of the Extract on the Stability of Sunflower Seed Oil as an Alternative to the Synthetic Antioxidant

Introduction: The addition of antioxidants is one of the ways to protect the oil from oxidation. The aim of this research is to obtain ferula persica plant extract using supercritical fluid method and measure the phenolic compounds and tocopherols and also to evaluate the effect on the oxidative stability of sunflower seed oil during storage. Materials and Methods: Using supercritical fluids (SCF), the ethanolic extracts at different concentrations (100, 1500, 2000 and 2500 ppm) were prepared. Total amount of phenolic compounds and tocopherols in the extracts were determined by the Folin–Ciocalteu and spectrophotometry procedures, respectively. The antioxidant activity was evaluated and the concentration of 2500 ppm showed the highest antioxidant activity, therefore, this concentration was selected and added to sunflower seed oil. The oil was kept at room temperature for 60 days and peroxide value, carbonyl number, oxidative stability index, total polar compounds and acid value were measured every 15 day and compared with the synthetic antioxidant (TBHQ 100 ppm). Results: The concentrations of phenolic compounds and tocopherols in the SCF extract were determined and found to be 1495.81 mg as gallic acid and 58.6 mg alpha-tocopherol per 100 gram of extract. Conclusion: Ferula persica extract at the concentration of 2500 ppm due to the presence of both phenolic compounds and tocopherols exhibited antioxidant acivity in sunflower seed oil and have the ability similar to TBHQ that results in increased oxidative stability of the substrate, therefore, Ferula persica that is a natural product might be considered as a potent antioxidant to improve the stability of oils and fats.