Antioxidants from a heated histidine-glucose model system. Investigation of the copper(II) binding ability

The metal binding ability of Maillard reaction products (MRP) was investigated by spectrophotometric monitoring for complex/chelate formation. In addition, the antioxidant activity of MRP, in the presence of Cu(II), was evaluated on a lipid model system consisting of sunflower seed oil/water (1:2). Results from the Rancimat test indicated a significant decrease in pro-oxidant ability of Cu(II) in the presence of MRP in contrast to histidine alone, whether heated or not. Results from the diphenylpicrylhydrazyl method showed that, in contrast to histidine (heated or not), the antiradical ability of MRP is reduced in the presence of Cu(II), but depends on the reaction time between MRP and Cu(II).