Study of Maillard reaction products derived from aqueous model systems with different peptide chain lengths

Maillard reaction products (MRPs) were prepared from aqueous model mixtures containing 0.2 M glucose and 0.2 M each of glycine, diglycine, and triglycine, heated at 100 degrees C, for different times (10, 60, 120, 180 and 240 min), with an initial pH control set to 7.8. The browning and intermediate products of MRPs derived from the Glu-Di model system were the most prominent. The pH of all MRP samples decreased considerably as the heating time increased (P < 0.05). The loss of glucose in MRPs derived from the Glu-Di model system was the highest, while the degree of sugar enolisation in MRPs derived from the Glu-Tri model system was the highest. The amino acid group content in MRPs derived from the Glu-Di model system was decreased noticeably. All MRP samples showed different absorptions in the UV-vis spectra, although they possessed similar shapes. The molecular weights of all MRP samples showed rising intensities as a function of the heating time, whereas the major peaks of each MRP sample were eluted at different retention times according to peptide chain lengths. (C) 2009 Elsevier Ltd. All rights reserved.