Antioxidative Activity of Melanoidin Decolorized by Coriolus versicolor IFO 30340

Abstract

The nondialyzable melanoidin prepared from D-xylose and glycine was decolorized by C. versicolor IFO 30340. The antioxidative activity of decolorized products on linoleic acid in aqueous system at pH 7.0 was investigated. By cultivation of C. versicolor in the basal medium containing melanoidin at 30°C for 12 days, its brown color was decolorized about 80 %. However, the decolorized melanoidin showed the same antioxidative activity as that of the melanoidin. By fractionating both media before and after cultivation with Sephadex G-25 column, the former gave only one peak by monitoring an optical density at 420nm, but the latter showed two peaks; high molecular melanoidin and low molecular one. On the other hand, both media gave two peaks on the same column by determination of total organic carbon, respectively. In the former, the low molecular substance was glucose added into the medium, but in the latter, unknown and considered to be the decolorized products by C. versicolor. When antioxidative activities of both substances in the decolorized melanoidin were compared at same weight level, strong antioxidative activity was distributed in the low molecular one. IR-spectrum of the melanoidin showed shoulder absorption at 1720cm^-1, but that of the decolorized one revealed sharp absorption of carbonyl group at same wave-number.