Spectroscopic Analysis of the Initial Step of the Maillard Reaction of <scp>d</scp>‐Fructose and <i>N</i>_α‐Acetyl‐<scp>l</scp>‐Lysine

ABSTRACT The Maillard reaction is a reaction between sugar and the amino group of proteins. Herein, N α ‐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.