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Water-soluble, nondialyzable Maillard polymers were prepared by reacting D-xylose with 15N-glycine (and/or glycine) at 68 ℃ and pH 8.0 at equimolar concentrations of 1, 0.5 and 0.1 mol L-1, respectively,for 13 days and partitioned into acid-insoluble (MHA) and acid-soluble (MFA) fractions. The nitrogen forms in these polymers were studied by using the 15N cross polarization-magic angle spinning nuclear magnetic resonance (CPMAS NMR) technique in combination with chemical methods. The 15N nuclear magnetic resonance (NMR) data showed that while the yield, especially the MHA/MFA ratio, varied considerably with the concentrations of the reactants, the nitrogen distribution patterns of these polymers were quite similar.From 65% to 70% of nitrogen in them was in the secondary amide and/or indole form with 24%~25% present as aliphatic and/or aromatic ammes and 5% to 11% as pyrrole and/or pyrrole-like nitrogen. More than half (50%~77%) of the N in these polymers were nonhydrolyzable. The role of Maillard reaction in the formation of nonhydrolyzable nitrogen in soil organic matter is discussed.
Water-soluble, nondialyzable Maillard polymers were prepared by reacting D-xylose with 15 N-glycine (and / or glycine) at 68 ° C and pH 8.0 at equimolar concentrations of 1, 0.5 and 0.1 mol L -1, respectively, for 13 days and The nitrogen forms in these polymers were studied by using the 15N cross polarization-magic angle spinning nuclear magnetic resonance (CPMAS NMR) technique in combination with chemical methods. The nitrogen forms in these polymers were studied by using the 15N cross polarization-magic angle spinning nuclear magnetic resonance (MMA) 15N nuclear magnetic resonance (NMR) data showed that while the yield, particularly the MHA / MFA ratio, varied considerably with the concentrations of the reactants, the nitrogen distribution patterns of these polymers were quite similar. Ferrom 65% to 70% of nitrogen in They were in the secondary amide and / or indole form with 24% to 25% present as aliphatic and / or aromatic ammes and 5% to 11% as pyrrole and / or pyrrole-like nitrogen. More than half (50% to 77% ) of the N in these polymers were nonhydrolyzable. The rol e of Maillard reaction in the formation of nonhydrolyzable nitrogen in soil organic matter is discussed.