Influence of pH on the antioxidant activity of model Maillard reaction products

The antioxidant activity (including ABTS radical scavenging activity and reducing power) of Maillard reaction products (MRPs) prepared by heating glucose with tyrosine and histidine under different initial pH levels were studied.The results showed that MRPs from glucose-tyrosine system showed the highest ABTS radical scavenging activity and the highest reducing power under alkaline condition;while MRPs from glucose-histidine system showed the highest ABTS radical scavenging activity under alkaline condition and the highest reducing power under acidic condition.Besides, for both glucose-tyrosine and glucose-histidine systems, the antioxidant activity of MRPs showed a good correlation with UV absorbance (A280nm) and browning intensity (A420nm) .