Effects of heated glucose–lysine and glucose–methionine model-systems on mineral solubility

Equimolar mixtures of glucose–lysine or glucose–methionine, 40% moisture, were heated at 150 °C for 30, 60, or 90 min. Samples were characterized by means of pH measurement, browning development and free amino acid content. Solubility assays were performed to study the influence of obtained MRPs on Ca, Mg, Fe, Cu and Zn solubility, under intestinal conditions of pH and ionic strength. Results showed that heated mixtures of glucose–lysine and glucose–methionine had little effect on Ca and Mg solubility. However, early compounds formed in both model systems seemed to favour trace element solubility, maximum after 30 min of heating in the glucose–lysine system, and after 60 min in the glucose–methionine one. Browning development and solubility results reflected the slowing down of the Maillard reaction when methionine was one of the reactants. The effects of browning products generated during food processing should be taken into account, particularly in trace element availability.