This study investigated the antioxidant content and activity of phenolic acids, anthocyanins, R-tocopherol
and γ-oryzanol in pigmented rice (black and red rice) brans. After methanolic extraction, the DPPH
free radical scavenging activity and antioxidant activity were measured. The pigmented rice bran
extract had a greater reducing power than a normal rice bran extract from a long grain white rice. All
bran extracts were highly effective in inhibiting linoleic acid peroxidation (60-85%). High-performance
liquid chromatography (HPLC) analysis of antioxidants in rice bran found that γ-oryzanol
(39-63%) and phenolic acids (33-43%) were the major antioxidants in all bran samples, and black
rice bran also contained anthocyanins 18-26%. HPLC analysis of anthocyanins showed that
pigmented bran was rich in cyanidin-3-glucoside (58-95%). Ferulic acid was the dominant phenolic
acid in the rice bran samples. Black rice bran contained gallic, hydroxybenzoic, and protocatechuic
acids in higher contents than red rice bran and normal rice bran. Furthermore, the addition of 5%
black rice bran to wheat flour used for making bread produced a marked increase in the free radical
scavenging and antioxidant activity compared to a control bread.