Spectroscopic Analysis of the Initial Step of the Maillard Reaction of d‐Fructose and Nα‐Acetyl‐l‐Lysine

Abstract

The Maillard reaction is a reaction between sugar and the amino group of proteins. Herein, Nα‐acetyl lysine (Ac‐Lys) and fructose were the model compounds. Structural information of the intermediates and products of the reaction at pH 7.4 and 37°C was obtained using UV–Vis absorption, fluorescence, and 785‐nm excited non‐resonance Raman spectroscopy. In the 6‐h reaction, three independent components in the spectroscopic data were attributed to the solvated reactants (A), their complex (B), and a covalent‐bonded product (C). The rate constant of the change in the fraction from A to B and B to C were (9.9 ± 0.1) × 10−3 and (3.3 ± 0.1) × 10−3 min−1, respectively. Polymeric Maillard reaction products were not yet formed. The structures of the solute molecules in each state were discussed based on the spectroscopic data.