NATURAL ANTIOXIDANT ACTIVITY OF RICE HULL AND BLACK RICE HULL EXTRACTS ON SUNFLOWER OIL

Hull from rice (RH) and black rice (BRH) were treated by methanol, ethanol and water to extract natural antioxidant Anti-oxidative activities of RH, BRH extracts as natural antioxidant and butylated hydroxyl-tolunene (BHT) as synthetic antioxidant were determined using a linoleic add system and measurement at 500nm. Natural and BHT antioxidants exhibited strong and close anti- oxidative activities from 94.29 to 84.29%. The RH,. BRH extracts and BHT were add separately to sunflower oil at levels of 0.01,0.02,0.05 and 0.10 % to keep its quality during heating at 180 ± 5C° for 28hour (4hour/day). Thiobarbituric add reactive substances (TBARS) and saponification number (SN) were determined in the sunflower oil at the end of heating period. The results showed that the addition of natural antioxidant extracts and BHT at 0.05 and 0.10% inhibited lipid peroxidation and improved its frying quality during heating with respect to the above mentioned properties.