Methyglyoxal

Bovine β-LG and methyglyoxal (40% aqueous solution) were obtained from Sigma-Aldrich (St. Louis, MO, USA). CML and carboxyethyllysine (CEL) (98%, HPLC) were obtained from Toronto Research Chemicals (Toronto, ON, Canada). Both pepsin and trypsin were sourced from Sigma-Aldrich (St. Louis, MO, USA). BHI medium was acquired from Thermo Fisher (Waltham, MA, USA). Acetonitrile and methanol for mass spectrometry were purchased from Merck (Darmstadt, Germany). Milli-Q water was employed in the experiments. All other reagents used were of analytical grade.

Glucose standard and acetic acid were purchased from Tianjin Yongda (Tianjin, PR China). 5-Hydroxymethylfurfural (HMF), 5-methylfurfural (MF), methyglyoxal (MGO; 40% solution in water), glyoxal (GO; 40% solution in water), o-phenylenediamine, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,7-dichlorofluorescin, Folin-Ciocalteu reagent and gallic acid were purchased from Sigma-Aldrich, Merck (St. Louis, MO, USA). Test kits used for the determination of total superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), malondialdehyde (MDA) and serum biochemical markers (alanine transaminase (ALT) aspartate transaminase (AST), alkaline phosphatase (ALP) and total bilirubin) were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, PR China). All reagents were of analytical grade.