Lysine-Derived Protein-Bound Heyns Compounds in Bakery Products

Abstract

Fructose and dicarbonyl compounds resulting from fructose in heated foods have been linked to pathophysiological pathways of several metabolic disorders. Up to now, very little has been known about the Maillard reaction of fructose in food. Heyns rearrangement compounds (HRCs), the first stable intermediates of the Maillard reaction between amino components and fructose, have not yet been quantitated as protein-bound products in food. Therefore, the HRCs glucosyllysine and mannosyllysine were synthesized and characterized by NMR. Protein-bound HRCs in cookies containing various sugars and in commercial bakery products were quantitated after enzymatic hydrolysis by RP-HPLC-ESI-MS/MS in the multiple reaction monitoring mode through application of the standard addition method. Protein-bound HRCs were quantitated for the first time in model cookies and in commercial bakery products containing honey, banana, and invert sugar syrup. Concentrations of HRCs from 19 to 287 mg/kg were found, which were similar to or exceeded the content of other frequently analyzed Maillard reaction products, such as N-ε-carboxymethyllysine (10-76 mg/kg), N-ε-carboxyethyllysine (2.5-53 mg/kg), and methylglyoxal-derived hydroimidazolone 1 (10-218 mg/kg) in the analyzed cookies. These results show that substantial amounts of HRCs form during food processing. Analysis of protein-bound HRCs in cookies is therefore useful to evaluate the Maillard reaction of fructose.

Solid-phase synthesis of d-fructose-derived Heyns peptides utilizing Nα-Fmoc-Lysin[Nε-(2-deoxy-d-glucos-2-yl),Nε-Boc]-OH as building block

“…The well-defined doublets at 4.76 ppm ( J = 8.3 Hz) and 5.31 ppm ( J = 3.5 Hz) are characteristic for β- and α-glucopyranosyl forms, respectively. All signals are in good agreement with previous reports (Jakas et al 2008 ; Krause et al 2008 ; Srinivas and Harohally 2012 ; Treibmann et al 2017 ; Ohno et al 2019 ). Based on the peak areas of the anomeric proton signals, the glucosyl derivative was present in α-pyranose (83%) and β-pyranose (17%) forms.…”

“…The singlets at 4.96 ppm and 5.21 ppm were assigned to β- and α-mannopyranosyl forms, respectively, and the doublet at 5.29 ppm ( J = 5.5 Hz) to the β-mannofuranosyl tautomer. The upshifted signal at 5.30 ppm ( J = 3.7 Hz) is supposed to correspond to the α-mannofuranosyl tautomer (Treibmann et al 2017 ). The difference in the coupling constant was attributed to an overlay with the α-glucopyranosyl form of the Fmoc-Lys(Glc)-OH impurity ( 1a , 8%).…”

Formation of advanced glycation endproducts in foods during cooking process and underlying mechanisms: a comprehensive review of experimental studies

“…Treibmann et al (74) determined the AGE (CML, CEL and methylglyoxal-derived hydroimidazolone (MG-H1) as important lysine and arginine AGE) content of cookies that were baked in a laboratory drying oven for 10 min at 175°C. The cookies that contained fructose, glucose, honey and banana had similar CML contents (6•22 (SD 0•71), 7•9 (SD 1•5), 6•940 (SD 0•057) and 7•67 (SD 0•18) mg/kg cookie, respectively).…”

Glycation of Plant Proteins: Regulatory Roles and Interplay with Sugar Signalling?

“…Glucose-derived Amadori compounds—amino-deoxyfructos-1-yl adducts, represent the best characterized glycation products [8]. Ketoamine intermediates undergo a similar reaction cascade, known as Heyns rearrangement [9], i.e., migration of a proton from C2 to C1 leading to the formation of 2-amino-deoxyaldos-1-yl adducts (Heyns products) [10,11]. These first relatively stable intermediates of glycation, known as “early glycation products” [12] are readily involved in further degradation, oxidation and cross-linking reactions, yielding “advanced glycation end products” (AGEs) [13].…”