Maillard reaction humification pathway

There has been some recent criticism of the Maillard reaction as a possible humification pathway (Burdon, 2001 Sutton and Sposito, 2005 von Liitzow et al., 2006). First, the critics argue that the Maillard reaction results in the formation of heterocyclic N, whereas soil N consists primarily of amide N based on 15N CPMAS NMR (Knicker and Liidemann, 1995 Knicker, 2004) studies. However, Jokic et al. (2004a) clearly showed, using N K-edge XANES, that the Maillard reaction catalyzed by bimessite under ambient temperature conditions and environmentally relevant pH not only produces heterocyclic N but also a significant amount of amide N (Figure 2.8). 

Hardie, A. G., Dynes, J. I, Kozak, L. M., and R M. Huang. (2007). Influence of polyphenols on the integrated polyphenol-Maillard reaction humification pathway as catalyzed by birnessite. Annals Environ. Sci. 1, 91-110. 

Jokic, A., Wang, M. C., Liu, C. Frenkel, A. I., and Huang, P. M. (2004b). Integration of the polyphenol and Maillard reactions into a unified abiotic pathway for humification in nature the role of 8-Mn02. Org. Geochem. 35, 747-762. 

Figure 1.6. Formation of the Amadori compound from D-glucopyranose (D-glucose) and glycine. Note that a molecule of water is split off. Tlie Amadori compound is an intermediate product in the Maillard reaction, which is perceived as one of the pathways in humification. (From Mossine et al., 1994.)...

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