Investigation of thermo-chemical properties of mechanochemically generated glucose-histidine Maillard reaction mixtures

Mechanochemistry is gaining increasing interest as an efficient tool for solvent-free organic transformations. Recently, it was applied to perform the Maillard reaction of glucose with various amino acids that lead to the selective formation of Schiff bases and their Amadori rearrangement products. In this study, we report the thermal properties of the mechanochemically generated glucose-histidine reaction mixtures. Direct video recordings of their melting behavior show that the browning of the ball-milled mixtures starts at lower temperatures and proceed more slowly compared to the non-milled mixtures. Furthermore, pyrolysis of ball-milled mixtures generated more pyrazines and fewer furan derivatives compared to the non-milled mixtures. The chemical composition of the ball-milled glucose-histidine was also investigated in depth by high-resolution mass spectrometry. The decarboxylation and C2-C3 sugar chain cleavage reactions were identified as the most important transformations during ball milling. These findings further support the utility of mechanochemically generated mixtures as potential Maillard flavor and browning precursors.