Antioxidant activity of water-soluble Maillard reaction products

Maillard reaction products (MRP) results from a condensation reaction between amino acids (or proteins) and reducing sugars or lipid oxidation products, and MRP exhibit in vitro antioxidant activities. The objective of this study was to determine antioxidant activities of water-soluble MRP from the reaction between histidine (His) and glucose (Glu) by using the oxygen radical absorbing capacity (ORACPE) assay with phycoerythrine. Heating His–Glu mixture at 100 °C up to 30 min did not generate MRP with antioxidant activity. However, significant formation of MRP with ORACPE values of 0.25, 0.43, and 0.44 μmol Trolox equivalent/mg reaction mixture was observed when the mixture was heated at 120 °C for 10, 20, and 30 min, respectively. Heating the mixture at 120 °C over 30 min reduced the peroxyl radical scavenging activity of the MRP, possibly due to the degradation of antioxidant MRP formed in the earlier stages of the reaction. In conclusion, MRP obtained from His–Glu mixture possesses peroxyl radical scavenging activity, and this activity can be quantified by the ORACPE assay.