Biological activities and physicochemical properties of Maillard reaction products in sugar–bovine casein peptide model systems

The purpose of this study was to evaluate the biological activities and physicochemical properties of Maillard reaction products (MRPs), derived from aqueous reducing sugar (ribose, galactose and lactose) and bovine casein peptide (BCP) model systems. The fluorescence intensity of ribose-BCP MRPs reached the maximum value within 1 h, while it took 3 h for galactose-BCP MRPs. Size exclusion chromatography of all the MRPs indicated molecular rearrangements and production of new smaller molecules, as a function of the heating time. The consumption of ribose and amino groups was the highest in the ribose-BCP MRPs. BCP lost its known angiotensin-I-converting enzyme (ACE) inhibitory activity by the Maillard reaction with reducing sugars. Ribose–BCP MRPs had the lowest ACE inhibitory activity, but they showed the highest 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity and ferrous reducing power among all the MRPs. Galactose-BCP MRPs inhibited, slightly the growth of Caco-2 cells, while ribose-BCPand lactose-BCP MRPs had no cytotoxicity.