Antioxidative Ability of Defatted Rice Bran Extract Obtained by Subcritical Water Extraction in Bulk Oil and Aqueous Dispersion Systems

Defatted rice bran was treated with subcritical water between 120 and 240°C. The extraction temperature af fected the total carbohydrate and protein contents of the extracts. In the tested temperature range, the total carbohydrate and protein contents were the highest at 180°C and 210°C. The DPPH radical scavenging activity of the extracts increased with increasing extraction temperature up to 240°C and showed a linear correlation with the total phenolic content. The antioxidative ability of the extracts was evaluated in both the bulk oil and aqueous dispersion systems of linoleic acid. The antioxidative ability dif fered in the two systems. The extract obtained at any temperature elongated the induction period for the oxidation of linoleic acid in the aqueous dispersion system. However, only the extract obtained at 240°C showed significant antioxidative ability in the bulk linoleic acid system.