Identification of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one as a strong antioxidant in glucose–histidine Maillard reaction products

The antioxidant activity of glucose-histidine MRPs (GH) and fractionated GH, obtained from the elution of GH on Bio-gel P-2 column, was evaluated for their DPPH radical scavenging activity, ABTS radical scavenging activity and reducing power, which illustrated that fraction H7 was of the greatest antioxidant activity. The further investigation identified 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) as the major compound in fraction H7 by employing GC-MS analysis and HPLC analysis, with the latter also confirming the antioxidant activity of DDMP by comparison of HPLC chromatograms of fraction H7 (or DDMP) before and after reaction with DPPH radical, ABTS radical or ferric ion. Finally, the comparison of the antioxidant activity of DDMP, fraction H7 and GH by UV-vis analysis showed their antioxidant activity was in the following order: DDMP> fraction H7> GH, suggesting that the major contribution of DDMP to the antioxidant activity of fraction H7, thus, DDMP could be identified as a strong antioxidant in GH considering that fraction H7 was of the greatest antioxidant activity among all fractions obtained from the separation of GH by gel filtration chromatography. (C) 2013 Elsevier Ltd. All rights reserved.