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

Abstract

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.

Lipid Peroxidation Has Major Impact on Malondialdehyde-Derived but Only Minor Influence on Glyoxal and Methylglyoxal-Derived Protein Modifications in Carbohydrate-Rich Foods

“…Within the present work, we also identified these novel amidine structures in wafer proteins. However, the absolute levels of GLA and MGLA were about factors of 4–6 lower compared to the corresponding imidazole cross-links GOLD and MOLD, which was also true for previous findings in meat protein and incubations. , …”

“…However, the absolute levels of GLA and MGLA were about factors of 4−6 lower compared to the corresponding imidazole cross-links GOLD and MOLD, which was also true for previous findings in meat protein and incubations. 4,22 Analytics of Malondialdehyde Protein Adducts. In respect of the lability of MDA-Lys, MDA-Lys 2 , and NPO as representatives for MDA protein adducts during acid protein hydrolysis (Table 5), we used an established enzymatic approach including a mixture of endo-and exopeptidases before HPLC−MS/MS analysis.…”

“…Authentic reference material N 6 -carboxymethyl lysine (CML), 20 N 6 -carboxyethyl lysine (CEL), N 6 -glycolyl lysine (GALA), 21 glyoxal lysine amidine (GLA), 22 glyoxal lysine dimer (GOLD), 21 glyoxal derived imidazoline cross-link (GODIC), N 6 -lactoyl lysine, 23 methylglyoxal lysine amidine (MGLA), 4 methylglyoxal lysine dimer (MOLD), 24 methylglyoxal derived imidazoline cross-link (MODIC), 25 N 7 -carboxyethyl arginine, MG-H1, and MG-H3 26 were synthesized or isolated from incubations according to the literature. The sodium salt of malondialdehyde was freshly prepared according to previous reports, and spectroscopic data corresponded to that in the literature.…”

“…1−3 Previously, we gave insights into the formation of 1,2dicarbonyl compounds and AGEs during the grilling of porcine meat. 4 Apart from the carbohydrate chemistry, glyoxal and methylglyoxal were also identified as products of lipid peroxidation and, thus, may contribute to the load of dicarbonyls within the processing of high-fat products like meat. 5 However, the relevance of this pathway under conditions of food processing is virtually unknown.…”

Role of Advanced Glycation End Products in Intervertebral Disc Degeneration: Mechanism and Therapeutic Potential

“…The unstable Schiff base undergoes rearrangement to form a more stable Amadori product [35]. The Amadori products undergo a series of reactions, rearrangements, and dehydrations to produce highly reactive dicarbonyl compounds, such as methylglyoxal (MG), glyoxal (GO), or deoxyglucone (1-deoxyglucone [1-DG] and 3-deoxyglucone ) [35][36][37]. Carbonyl stress is caused by continuous accumulation of dicarbonyl compounds [38].…”