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.

Automated summary

This study investigated changes in carbohydrates, dicarbonyl structures, and 11 AGEs during the grilling of porcine meat patties. Results showed an increase in methylglyoxal-derived AGEs after grilling, with N-6-lactoyl lysine being the major AGE possibly due to nonenzymatic acylation.