Characteristics and antioxidant activity of Maillard reaction products derived from chitosan-sugar solution

The Maillard reaction occurring between amino group and carbonyl group produces neo-formed compounds having certain levels of antioxidant activity depending on the reaction conditions and the type of reactants. In this study, maillard reaction products (MRPs) derived from four model systems including chitosan-glucose (CG), chitosan-fructose (CF), chitosan-maltose (CM) and chitosan-lactose (CL) solutions were prepared by heating at 100 °C for various times (0, 1, 2, 3, 4, 5, 6 and 7 h) and their characteristics and antioxidant activity were investigated. Browning intensity and intermediate products, as monitored by A420 and AUVλmax, increased with heating time. The increase in browning intensity and formation of intermediate products were concomitant with the decreases in free amino group and reducing sugar contents. DPPH radical scavenging activity, FRAP, reducing power, hydroxyl radical scavenging activity and inhibition of lipid peroxidation of all MRPs derived from chitosan-sugar model systems increased with the increase in browning intensity and intermediate formation. Among all MRPs tested, those derived from CG system rendered the highest browning intensity, intermediate products and antioxidant activity as evidenced by the greatest scavenging effect, reducing power, hydroxyl radical scavenging activity and inhibition of lipid peroxidation. Thus, MRPs derived from chitosan-sugar model system can be promoted as a novel antioxidant to prevent lipid oxidation in food system.