Formation mechanism of cross-linking Maillard compounds in peptide-xylose systems.

The formation mechanism of Maillard peptides was explored in Maillard reaction through diglycine/glutathione(GSH)/(Cys-Glu-Lys-His-Ile-Met)-xlyose systems by heating at 120 °C for 30-120 min. Maximum fluorescence intensity of Maillard reaction products (MRPs) with an emission wavelength of 420~430 nm in all systems was observed, and the intensity values were proportional to the heating time. Taken diglycine/GSH-[(13) C(5) ]xylose systems as a control, it was proposed that the compounds with high m/z values of 379 and 616 have the high molecular weight (HMW) products formed by cross-linking of peptides and sugar. In (Cys-Glu-Lys-His-Ile-Met)-xylose system, the m/z value of HMW MRPs was not observed, which might be due to the weak signals of these products. According to the results of gel permeation chromatography, HMW MRPs were formed by Maillard reaction, especially in (Cys-Glu-Lys-His-Ile-Met)-xylose system, the percentage of Maillard peptides reached 52.90%. It was concluded that Maillard peptides can be prepared through the cross-linking of sugar and small peptides with a certain MW range.