Quantification of Nε-(2-Furoylmethyl)-l-lysine (furosine), Nε-(Carboxymethyl)-l-lysine (CML), Nε-(Carboxyethyl)-l-lysine (CEL) and total lysine through stable isotope dilution assay and tandem mass spectrometry

Abstract

The control of Maillard reaction (MR) is a key point to ensure processed foods quality. Due to the presence of a primary amino group on its side chain, lysine is particularly prone to chemical modifications with the formation of Amadori products (AP), Nε-(Carboxymethyl)-L-lysine (CML), Nε-(Carboxyethyl)-L-lysine (CEL). A new analytical strategy was proposed which allowed to simultaneously quantify lysine, CML, CEL and the Nε-(2-Furoylmethyl)-L-lysine (furosine), the indirect marker of AP. The procedure is based on stable isotope dilution assay followed by liquid chromatography tandem mass spectrometry. It showed high sensitivity and good reproducibility and repeatability in different foods. The limit of detection and the RSD% were lower than 5 ppb and below 8%, respectively. Results obtained with the new procedure not only improved the knowledge about the reliability of thermal treatment markers, but also defined new insights in the relationship between Maillard reaction products and their precursors.

The Impact of Different Drying Techniques and Controlled Storage on the Development of Advanced Glycation End Products in Skim Milk Powders Using Isotope Dilution ESI-LC-MS/MS

“…The CML concentration in the reference sample was 228.81 ± 11.44 mg/kg protein, and our results for skim milk powders before the storage (t = 0) are within the reported range of previous studies on milk and milk powder (Fenaille et al 2006;Bosch et al 2007;Hull et al 2012;Troise et al 2015;Drusch et al 1999) ( Table 1). …”

“…Therefore, there is an urgent need to address this issue. Hence, quantification of CML as one of the significant AGEs in milk products and as a disputed issue has been carried out by either immunochemical or instrumental methods (Hull et al 2012;Troise et al 2015;Ahmed et al 2005;Takeuchi et al 2015;Drusch et al 1999;Fenaille et al 2006;Bosch et al 2007;Hartkopf et al 1994;Tareke et al 2013;Dittrich et al 2006;Schwarzenbolz et al 2016;Plaza et al 2016). A problem, however, is that comparison of the results obtained by the two groups of methods is not possible since the results are reported in different units (kilounits/100 g food and mg/kg food).…”

“…Moreover, accurate data on CML concentration in foods based on a reliable instrumental method such as LC-MS/MS is very limited. Higher sensitivity and accuracy, better reproducibility, and no need for derivatization are the advantages of LC-MS/MS (Poulsen et al 2013;Tareke et al 2013;Troise et al 2015). Although a few studies reporting concentration of CML in food model systems can be found (Lima et al 2010;Nguyen et al 2016), the data on CML concentration in real complex food systems especially during storage is scarce.…”

Evolution of protein bound Maillard reaction end-products and free Amadori compounds in low lactose milk in presence of fructosamine oxidase I

“…Protein bound MRPs and total lysine were quantified according to the procedure previously described (Troise, Fiore, Wiltafsky, & Fogliano, 2015). Briefly, 4 mL of hydrochloric acid (6 M) were added to 0.1 mL of each sample in a screw capped flask with PTFE septa.…”

“…Positive electrospray ionization in MRM mode was used for the detection by using an API 3000 triple quadrupole (ABSciex, Carlsbad, CA). The characteristic transitions, the source parameters and the nebulizing condition were optimized according to our previous paper (Troise, Fiore, Wiltafsky, et al, 2015).…”