Evaluation of the effectiveness of cereal bran extract for sunflower oil stability during frying

Abstract

This study evaluated the effectiveness of black rice, millet and barley bran extracts against oxidative degradation of sunflower oil in frying, by determining the total antioxidant activity, total phenolic content, free fatty acid content, conjugated diene content and total polar content. It was reported that the total phenolic content rice bran was approximately three times higher than that of the millet bran extracts and five times higher than the results for barley bran extracts. The total antioxidant activity results for barley bran and rice bran extract (40.95 ± 0.07and 40.87 ± 0.04 Trolox equivalent μmol/g of bran, respectively) were two times higher than that of millet bran extract (17.16 ± 0.34 Trolox equivalent μmol/g of bran). The results of the effectiveness of the cereal bran extracts were significantly different (p<0.05). The free fatty acid content of the rice bran and propyl gallate enriched oil samples showed better results (2.02 ± 0.01% and 1.62 ± 0.00%) than millet, barley and control enriched oil samples (3.43 ±0.01%, 3.13±0.01% and 6.13 ± 0.01% respectively). In the same vein, conjugated diene content results from all the enriched oil samples indicated that the rice bran enriched oil sample had the least amount of secondary oxidized products compared to the other enriched oil samples. It can be concluded that rice bran extract can be used for frying without discarding or replenishing the oil.