title: Chemical characterization of different sugar-casein Maillard reaction products and protective effects on chemical-induced cytotoxicity of Caco-2 cells.
abstract: This study examined the chemical modification of casein with three monosaccharides [e.g., glucose (Glc), fructose (fru), and ribose (Rib)], following prolonged gentle heating to product the Maillard reaction (MR). Changes in chemical modification of casein in different sugar-casein MR was monitored using temporal patters of change in fluorescence development, UV absorbance and casein molecular mass, which was studied using SDS-PAGE and MALDI-TOF mass spectrometry. Rib-casein MRP exhibited significantly (p<0.05) advanced fluorescence development at three days, compared to Glc- and Fru-casein MRPs, which corresponded to marked (p<0.05) differences in greater UV absorption of Rib-casein MRPs later on after 15 days of processing. These results were associated with the generation of different high molecular weight complexes generated from the Rib-casein MR, compared to Glu- and Fru-casein MRPs, respectively. Antioxidant activity of all three sugar-modified caseins was also assessed when cultured with Caco-2 cells. A significant, but similar protective effect against 2,2'-azobis-(2-amidinopropane)dihydrochloride (AAPH) radical-induced cytotoxicity, and ferrous- and cupric-induced toxicity of Caco-2 cells was observed for all three sugar-casein MRPs. However, these protective effects were not significantly different among the sugar-modified caseins and native casein. The results suggest that protection of Caco-2 cells from free radical-ferrous- and cupric-induced cytotoxicity by casein was not altered by modification by MR, regardless of source of monosaccharide involved in the reaction.
authors.affiliation: Department of Food, Nutrition and Health, Faculty of the Agricultural Sciences, The University of British Columbia, 6640 N.W. Marine Drive, Vancouver, BC, Canada V6T 1Z4.
authors.forename: Hao
authors.initials: H
authors.lastname: Jing
authors.forename: David D
authors.initials: DD
authors.lastname: Kitts
mesh_terms: D000578:Amidines / Q000633:toxicity; D018938:Caco-2 Cells; D002364:Caseins / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D005453:Fluorescence; D005632:Fructose / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D015416:Maillard Reaction; D008970:Molecular Weight; D009005:Monosaccharides / Q000737:chemistry*; D016877:Oxidants / Q000633:toxicity; D012266:Ribose / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000578:Amidines; D002364:Caseins; D009005:Monosaccharides; D016877:Oxidants; D005632:Fructose; D012266:Ribose; C046728:2,2'-azobis(2-amidinopropane); D005947:Glucose