Influence of epicatechin reactions on the mechanisms of maillard product formation in low moisture model systems

The influence of the polyphenols compound epicatechin on Maillard chemistry was investigated under simulated roast conditions (10% moisture at 220°C for 10 min). Quantitative gas chromatography (GC) analysis indicated that the addition of epicatechin to glucose or fructose/glycine model systems significantly reduced the generation of hydroxyacetone, 2-methylpyrazine, 2,3,5-trimethylpyrazine, furfural, 2-acetylfuran, 5-methylfurfural, 2(5H)-furanone, 2-acetylpyrrole, and furfuryl alcohol. These analytes were reported to be primarily generated from intact C₂, C₃, C₄, C₅, and C₆ sugar fragments based on gas chromatography/mass spectrometry quantitative isotopomeric analysis of a 1:1 ¹³C₆:¹²C₆ hexose sugar/glycine model system. Liquid chromatography/mass spectrometry qualitative isotopomeric analysis of a 1:1 ¹³C₆:¹²C₆ hexose sugar/glycine/epicatechin model systems confirmed epicatechin reacted with Maillard reactants in the model systems; two main reaction products were reported, epicatechin-C₅ and -C₆ sugar fragment adducts. In addition, LC/MS analysis of a model system consisting of only 3-deoxy-2-hexosulose and epicatechin identified 3-deoxy-2-hexosulose as a precursor of the epicatechin-C₅ and -C₆ sugar fragment adducts reaction products. These results imply that epicatechin quenched 3-deoxy-2-hexosulose (a key source C₆ to C₁ sugar fragments) and consequently inhibited Maillard product formation.