SEPARATION OF MODEL MELANOIDIN INTO COMPONENTS WITH COPPER CHELATING SEPHAROSE-6B COLUMN CHROMATOGRAPHY AND COMPARISON OF CHELATING ACTIVITY

Nondialyzable model melanoidin prepared from glucose-glycine was separated into 6 components by pH gradient elution on a copper chelated Sepharose 6B column. The separated components were measured for copper chelating activity, UV-VIS spectrophotometry, and electrofocusing. The UV-VIS spectra of these components were found to be almost the same, but the melanoidin components with stronger affinity to the Cu column were found to be smaller in Kd. Their electrofocusing profiles were similar, and the electrofocused bands were categorized into four major groups with pI 2.5-4.0. Major chelating activity of the melanoidin components was due to a band of pI 2.7 on the electrofocusing.