Synthesis and characterization of Maillard compounds formed under sterile conditions on sand- and silt-sized mineral substrates

Maillard compounds were synthesized from D-glucose and glycine to mimic the separation of particles during a volcanic eruption so that the role of quartz and volcanic ash, fractionated into silt- and sand-size particles, could be tested under sterile conditions. The obtained polymers were separated into two fractions of 1000-8000 and > 8000 Daltons. The results evidence the formation of humus-like polymers from simple compounds and show the importance of substrate mineralogy. Specifically, a) humic-like polymers can form in the absence of microbial life, b) the role of particle size is important, c) mineral substrates enhance their yields, d) the polymers on volcanic ash and quartz show differences, e) their structure changes with time, f) at the end of the experiments there is an increase of unsaturation while the aliphaticity decreases, and g) the yields of the compounds of 1000-8000 Daltons decrease with time unlike those > 8000.