An. Wijewickreme et al., REACTION CONDITIONS INFLUENCE THE ELEMENTARY COMPOSITION AND METAL CHELATING AFFINITY OF NONDIALYZABLE MODEL MAILLARD REACTION-PRODUCTS, Journal of agricultural and food chemistry, 45(12), 1997, pp. 4577-4583
Nondialyzable glucose-lysine (Glu-Lys) and fructose-lysine (Fru-Lys) M
aillard reaction products (MRPs) were synthesized by reacting 0.8 M L-
lysine with 0.8M D-glucose or 0.8 M D-fructose using 14 different comb
inations of reaction time, temperature, initial pH, and initial water
activity. The extent of browning in each reaction was monitored by UV-
vis absorbance spectra, absorbance at 420 nm, and the yield of nondial
yzable MRPs. Crude MRPs were fractionated further by immobilized metal
affinity chromatography. Although the relative concentration and the
number of unidentified intermediate compounds present in Glu-Lys and F
ru-Lys MRP mixtures varied considerably, two principal components for
both Glu-Lys and Fru-Lys MRP mixtures with molecular masses of approxi
mately 5700 and 12 400 Da were identified by MALDI-MS. Elementary comp
osition and copper chelating affinity of crude and fractionated MRPs w
ere greatly influenced by type of reactant sugar and reaction conditio
ns used for synthesis. Glucose, in general, produced MRPs with relativ
ely higher copper chelating affinity, possessing higher percentages of
carbon and lesser percentages of nitrogen compared to counterpart Fru
-Lys MRPs.