Extracts of orange peel (Balady Var.) with different organic solvents (methanol, petroleum ether, ethanol diethylether, hexan and acetone) were studied. Methonol proved the best solvent for yeild extract. Antioxidant activity of sunflower oil treated with different concentrations of methanolic extracts of orange peel (MEOP) were also studied by determining peroxide value (POV), free fatty acid (FFA) and iodine value (IV) during 5 months storage at room temperature (20 + 3 OC)., Result indicated that: Orange peel is considered as a good source of polyphenols. Methanol proved the best solvents of yield extracts and also polyphenol contents.
The higher concentration of MEOP, the Lower value of (POV) and FFA) and the higher value of IV was observed during storage at the end of storage. Sunflower oil treated with 1500 and 2000 ppm of MEOP showed a significant (p≤ 0.05) lower value of POVs (6.90 and 6.77 meq/ kg-1); FFA (0.280%, 0.275%) and higher IVs (67.0 and 70.3). Meanwhile, refined oil (POVs 77.3 meq/ kg-1, FFA 0.710 and 1V, 51.2), respectively. Addition of BHT and BHT with 200 ppm showed POVs(10.4 and 8.80 meq/ kg-1); FFA (0.251 and 0.270) and IVs(71.3 and 71.0), respectively.
MEOP proved their strong efficiency as a natural antioxidant activity as compared to BHT and BHA, therefore it is suggested that it can safety be used instead of synthetic antioxidants for preservation of oils and fats from peroxidation and rancidity.
Keywords: orang, citrus peel extract, sunflower oil, flavanone polyphenols, antioxidant activity, flavonoids.