Characteristics and antioxidative ability of defatted rice bran extracts obtained using several extractants under subcritical conditions

Abstract

Defatted rice bran was treated with water, 50% (v/v) ethanol, ethanol, 50% (v/v) acetone, or acetone. The treatment temperature and time were fixed at 230°C and 5 min, respectively. The treatment with 50% (v/v) acetone produced the highest yield of 0.549 g-extract/g-bran, and the extract exhibited the highest DPPH radical scavenging activity of 0.495 mmol-ascorbic acid/g-extract. The extract obtained with 50% (v/v) acetone showed the higher UV absorbance and highest amount of hydrophobic substances in the HPLC analysis than the other extracts, and it also showed the highest antioxidative ability in both the rancidity test at 105°C and bulk oil system at 60°C for the longest induction period of 4.9 h and 14.4 h, respectively. However, the extracts obtained using various extractants showed no effect on the oxidation rate constant of linoleic acid in the bulk oil system. © 2013 by Japan Oil Chemists' Society.