Probing the effect of physical modifications on cereal bran chemistry and antioxidant potential

Abstract

Bran is the highly nutritious protective covering of cereal grains. Important health-benefitting compounds like dietary fiber, phenolics and antioxidants, vitamins and minerals are found in bran in good proportions. However, bran is discarded as a byproduct in milling operations and not used in substantial quantities in human foods because of some technical problems. Modification of cereal brans can improve their technological aspects and utilization in end-products. In this project, brans from seven cereals (wheat, barley, millet, sorghum, rice, oat and corn) were physically modified. The techniques included soaking, autoclaving and dry heat treatment. The effects of these modifications on chemical and antioxidant composition of bran were evaluated. Dry heat treatment improved the fiber content while a decreasing trend for TPC, TFC and antioxidant activity was observed. Highest TPC and TFC were observed in native sorghum (0.58 ± 0.01 mg GAE/g) and native millet bran (214.09 ± 0.16 µg QE/g) respectively. Antioxidant activity assayed by DPPH analysis was also highest in native millet bran (86.83 ± 0.05% inhibition). Tannins were highest in rice bran (182.85 ± 0.51 mg/100 g). Rice and corn bran had highest quotients of phytic acid as 6.35 ± 0.13 and 6.13 ± 0.15 g/100 g respectively. Modification treatments particularly dry heat treatment was effective in lessening the anti-nutritional factor.