Antioxidant Activity of Different Solvent Extracts of Rice Bran at Accelerated Storage of Sunflower Oil

The antioxidant activity of different extracts of rice bran (var. Super Kernel) prepared using a number of solvents (100% methanol, 80% methanol, 100% acetone and 80% acetone) were evaluated in sunflower oil (SFO) under accelerated storage conditions. The crude concentrated extracts of rice bran were added at 600 mg/kg into refined, bleached and deodorized SFO samples and stored under accelerated (65C) conditions for 24 days. Analyses were done every 4 days, and the extent of oxidative deterioration was followed by measurement of activity index, peroxide, p ‐anisidine, and conjugated diene and triene values. The overall order of antioxidant efficacy of rice bran extracts as determined by various antioxidant assays was 80% methanolic extract, > 100% methanolic extract, > 80% acetone extract and > 100% acetone extract. The antioxidant activity of rice bran extracts might be attributed to the presence of phenolics and high contents of tocopherol. The results of the present comprehensive analysis demonstrated that extracts of the rice bran of Super Kernel, an indigenous cultivar of Pakistan, are a viable source of natural antioxidants and might be exploited for functional foods and nutraceutical applications.