Browning reaction products prepared from a mixture of glycine and D-xylose by heating at 100°C for 30min., 2hr. and 3hr. were fractionated on Sephadex G-50. Fractionation of the resulting brown products heated for 30min. gave only one peak (fraction 42), but along with prolonged heating time, another high molecular melanoidin and reductone emerged in fraction 19 (sample heated for 2hr.) and 15 (sample heated for 3hr.). Strong antioxldative activity among fractions tested was found in the fraction which contained low molecular melanoidin. High molecular melanoidin in fractions which eluted more rapidly showed pro-oxidative effect on linoleic acid.
A mixture of fraction 11 and 12 separated by chromatography using G-15 was submitted to rechromatography with sephadex G-50. The rechromatography gave two peaks in color density and reductone content. The strongest antioxidative activity was recognized in fraction 39 but high molecular melanoidin showed little contribution to the activity.