Antioxidant activity and chemical properties of crude and fractionated Maillard reaction products derived from four sugar-amino acid Maillard reaction model systems.

Antioxidant activity of Maillard reaction products (MRPs) derived from four sugar-amino acid Maillard reaction model systems (glucose [Glc] or ribose [Rib] reacted with glycine [Gly] and L-lysine [Lys]) were examined in terms of chemical properties and molecular weight fractionation of reaction products. Rib-amino acid model systems produced MRPs with higher antioxidant activity than Glc-amino acid model MRPs (P < 0.05, Rib-Lys > Rib-Gly > Glc-Lys > Glc-Gly). In the same sugar or same amino acid model systems, antioxidant activity of MRPs was negatively related to the final pH, fluorescent intensity, and the content of dicarbonyl compounds. Antioxidant activity positively related to the production of late-stage browning MRPs. Fraction I from the Glc-Lys model system separated by gel filtration chromatography had the highest oxygen radical absorbance capacity (ORAC) value (1736 micromol Trolox/g MRP). Fraction IV from the Rib-Lys model system had a higher ORAC value compared to Fraction III. This result indicated that high molecular weight MRPs do not necessarily have higher antioxidant activity compared to low molecular weight MRPs.