Production and characterization of functional substances from a by-product of rice bran oil and protein production by a compressed hot water treatment

A by-product of rice bran oil and protein production was treated with water and compressed hot water at 20°C to 260°C for 5 min, and at 200°C and 260°C for 5 to 120 min. Each extract was evaluated for its yield, radical scavenging activity, carbohydrate, protein, total phenolic and furfural contents, molecular-mass distribution and antioxidative activity. The maximum yield was obtained at 200°C. The radical scavenging activity and the protein, total phenolic and furfural contents of the extract increased with increasing temperature. However, the carbohydrate content abruptly decreased when treated at above 200°C. The extract treated at 260°C for 5 min exhibited suppressive activity toward the autoxidation of linoleic acid. Each extract obtained at temperatures lower than or equal to 200°C exhibited emulsifying ability.