46C-21 |
Effect of far-infrared treatment on the antioxidant activity of rice hulls |
J. H. KIM1, S. M. Jeong1, H. J. Kim1, S. Ko2, D. U. Ahn3, J. U. Ha1, and S. C. Lee1. (1) Dept. of Food Science and Biotechnology, Kyungnam University, 449 Wolyoung-dong, Masan, 631-701, South Korea, (2) Dept. of Biological Engineering, University of Missouri, 146 Agricultural Engineering Bldg., Columbia, MO 65211, (3) Dept. of Animal Science, Iowa State University, 2275 Kildee Hall, Ames, IA 50011-315 Rice is the principal cereal in Asia, some countries in Africa and Latin America. More than 1,000,000 tons of rice hulls have been produced annually in South Korea after processing of rice. Rice hulls contain an antioxidant defense system to protect rice against oxidation. However, many natural plant antioxidants of low molecular weight compounds exist in the native products as repeating subunits of high molecular weight polymers. Far infrared (Far-IR) treatment is known as one of methods to liberate and activate low molecular weight natural antioxidants. The objective of this work was to determine the effect of Far-IR treatment on the antioxidant activity of rice hulls. Rice hulls (5.0g) in a wooden box (50 cm x 40 cm x 40 cm) were treated with a Far-IR lamp (output 300 W) for 120 min, and methanolic extracts (methanol/rice hull, 100mL/3g) were prepared. The antioxidant activities were determined by measuring changes in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability (RSA), total phenol contents, and lipid peroxidation of extracts. After 120 min of Far-IR treatment, RSA and total phenol contents in rice hulls extracts increased from 47% to 83% and from 2.32 mM to 3.51 mM, respectively, compared to control. The inhibition of lipid peroxidation was also increased from 41.07% to 48.44%. These results showed that Far-IR treatment of rice hulls contributed to the liberation and activation of antioxidants from polymers. Therefore, Far-IR treatment could be useful and effective in liberating and activating antioxidant compounds from rice hulls.
Session 46C, Food Chemistry: Lipids, antioxidants and emulsifiers
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