| dc.description.abstract | The use of black liquor, spent liquor produced from pulp processing, can be increased through isolation and purification to produce various useful products. One of the components in the liquor is lignin. Lignin was isolated from black liquor by precipitation using H2S04 20%. Lignin has potential application as an antioxidant. Phenolic hydroxyl groups in lignin can scavenge the free radicals. In this study, antioxidant activity of lignin, which is isolated from black liquor of Acacia mangium wood as the raw material, was examined by diphenyl picrylhydrazyl (DPPH) method. Lignin would scavenge the DPPH free radicals and change the color from purple to pale yellow of diphenyl picrylhydrazine. The change of color intensity was measured by ultraviolet-visible spectrophotometer. The result showed that lignin had strong antioxidant activity with 50% inhibition concentration (IC50) value of 18 ppm, higher than 3,5-di(t-butyl)-4- hydroxytoluene with IC50 value of 1880 ppm. Antioxidant activity of lignin was increasing with the increasing phenolic hydroxyl content and the decreasing lignin molecular weight | en |
