Pedosphere 7(3): 199--206, 1997
ISSN 1002-0160/CN 32-1315/P
©1997 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Nitrogen Forms of Maillard polymers derived from xylose and 15N-labelled glycine |
| CHENG Li-Li, WEN Qi-Xiao and CHEN Bi-Yun |
| Institute of Soil Science, Academia Sinica, P.O. Box 821, Nanjing 210008 (China) |
| ABSTRACT |
| 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 polarisation-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 amines 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. |
| Key Words: Maillard polymer, nitrogen form, 15N cross polarisation-magic angle spinning nuclear magnetic resonance (CPMAS NMR) |
| Citation: Cheng, L. L., Wen, Q. X. and Chen, B. Y. 1997. Nitrogen Forms of Maillard polymers derived from xylose and 15N-labelled glycine. Pedosphere. 7(3): 199-206. |
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