ISOLATION AND CHARACTERIZATION OF THE MOST ANTIMUTAGENIC MAILLARD REACTION-PRODUCTS DERIVED FROM XYLOSE AND LYSINE

The Maillard reaction products were prepared by refluxing D-xylose and L-lysine at 100-degrees-C and pH 9.0 for 10 h and then fractionated into various molecular weight (MW) ranges by membrane filters. The most antimutagenic effect toward 2-amino-3-methylimidazo[4,5-f]quinoline was observed in the fractions of MW 30 000-50 000 and MW 50 000-100 000 toward TA98 and MW 50 000-100 000 toward TA100, whereas the fraction of MW 50 000-100 000 showed the strongest activity against 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole toward TA98 or TA100 at the dose of 0.8 mg/plate. Fractions with MW above 30 000 showed inhibitory effect to 4-nitroquinoline N-oxide and N-methyl-N-nitro-N'-nitrosoguanidine on TA100. No significant correlations (P > 0.05) were observed between the antimutagenicity of each fraction and the browning intensity, reducing power, and antioxidative activity. The fraction with MW 50 000-100 000 was further separated by Sephadex G-100 and HPLC, and the peak GIIa exhibited the strongest antimutagenic effect with molecular weight about 63 000.