2000 Volume 6 Issue 2 Pages 79-86
Maillard reaction occurs extensively in food systems and in vivo. In an intermediate Maillard reaction of proteins with glucose, 3-deoxyglucosone (3DG) was generated from Amadori compounds in an early stage, leading to generation of advanced glycation endproducts (AGEs). 3DG modified lysine residues to form pyrrole aldehydes (lysyl-pyrraline), and arginine residues to form imidazolone compounds, and is speculated to be a cross-linker responsible for the polymerization of proteins. 3DG is also thought to be related to the evolution of fluorescence during Maillard reaction. The fluorescent compound has been identified as lysyl-pyrropyridine which is formed by the loss of five molecules of water from the reaction between 2 molecules of lysine residues and 2 molecules of 3DG. In the protein-glucose and pentose reaction systems, crossline and pentosidine have reportedly been formed as fluorescent and crosslinking compound, respectively, as well as pyrropyridine. Immunochemical and chemical methods have clearly indicated the progressive accumulation of AGEs in tissue proteins in aging. In diabetes, AGE accumulation in general is accelerated and linked to arteriosclerosis, nephropathy, neuropathy, retinopathy, and cataract. 3DG, which has weaker mutagenicity, reacted readily with 2′-deoxyguanosine in nucleosides. Two major products (G-A and G-B) were isolated, and G-A was identified as N-(1-oxo-2,4,5,6-hydroxyhexyl)-2′-deoxyguanosine. G-B was identified as a diastereomer of G-A. Blue pigment was isolated from the reaction between D-xylose and glycine. Blue pigment which was designated Blue-M1 (blue Maillard reaction intermediate-1) was identified as novel pyrrolopyrrolylium compound and is assumed to be a dimer of yellow colored pyrrolopyrrole-2-carboxaldehyde compounds. Blue-M1 that reacts readily to yellow compounds has a polymerizing activity, suggesting that it is an important Maillard reaction intermediate through the formation of melanoidins. Melanoidins have many positive physiologic effects.
