Geopolymerization of biopolymers: a preliminary inquiry

The Maillard reaction occurring in biopolymers was investigated to prove that biopolymers could convert to geopolymers over the years. Melanoidin chromophore was used as a marker for the Maillard reaction to take place. A characteristic property of geopolymers is the high content of humic materials, particularly humic and fulvic acids containing melanoidin. Chitosan can play the role of nitrogen functional groups, forming the precursor of the melanoidin compound. We observed the absorption peak that is identified by UV-Vis Spectrometry, in the chitosan as well as in the glucose-glycine or glucosamine, respectively. This peak represents the formation of melanoidin, the Maillard product. However, xanthan gum, not containing nitrogenous functions, did not yield the melanoidin peak. The Maillard reactions are dependent upon temperature and reaction time, and occurred in the following experiments: glucosamine, chitosan plus glucose, chitosan plus glucosamine, xanthan gum plus tea, and xanthan gum plus urine. These reactions also depend on the carbohydrate molecules as well as on the existence of nitrogen functional groups. Simple Maillard reaction in biopolymers can help simulate a possible pathway for the geopolymerization phenomena in natural environments. (C) 2004 Elsevier Ltd. All rights reserved.