Exploring polymerisation of methylglyoxal with NH3 or alanine to analyse the formation of typical polymers in melanoidins

Abstract

To investigate the formation of typical melanoidin polymers, methylglyoxal (MGO) with NH₃ or alanine (Ala) was used to form coloured compounds, with glyoxal or acetone used as controls. The products were characterised using chromatography, mass spectrometry, and spectroscopy. Spectroscopic results showed that the coloured compounds formed were similar to melanoidins in food. GC-MS results showed that the MGO-based reaction generated similar volatile compounds using the Maillard reaction. Mass spectrometry showed that the molecular weights of structural units in the polymers were mainly 162, 169, and 176 Da, and these could be reassembled using the basic units derived from MGO alone or in combination with nitrogen. Hence, polymers recombined using basic structural units should be considered while determining melanoidin biomarkers. The preparation of coloured compounds using MGO with NH₃ can be used as a novel method to produce the control compounds for melanoidin after process optimization.

Keywords: Aldol reaction; MALDI-TOF-MS; Maillard reaction; Melanoidins; Methylglyoxal; Polymers.