Analysis of Glyoxal- and Methylglyoxal-Derived Advanced Glycation End Products during Grilling of Porcine Meat.

The reaction of the N 6 -amino group of lysine residues and 1,2-dicarbonyl compounds during Maillard processes leads to advanced glycation end products (AGEs). In the present work, we deliver a comprehensive analysis of changes of carbohydrates, dicarbonyl structures, and 11 AGEs during the grilling of porcine meat patties. While raw meat contained mainly glyoxal-derived N 6 -carboxymethyl lysine (CML), grilling led to an increase of predominantly methylglyoxal-derived AGEs N 6 -carboxyethyl lysine (CEL), N 6 -lactoyl lysine, methylglyoxal lysine dimer (MOLD), and methylglyoxal lysine amide (MOLA). Additionally, we identified and quantitated a novel methylglyoxal-derived amidine compound N 1 , N 2 -di-(5-amino-5-carboxypentyl)-2-lactoylamidine (methylglyoxal lysine amide, MGLA) in heated meat. Analysis of carbohydrates suggested that approximately 50% of the methylglyoxal stemmed from the fragmentation of triosephosphates during the heat treatment. Surprisingly, N 6 -lactoyl lysine was the major AGE, and based on model incubations, we propose that approximately 90% must be explained by the nonenzymatic acylation of lysine through S -lactoylglutathione, which was quantitated for the first time in meat herein.