Improvement of antioxidant activity of acid-precipitated soy proteins by conjugating to maltodextrin through maillard reaction

The aim of the present study was to identify changes in the antioxidant properties of soy proteins. Soy proteins- maltodextrin conjugates were prepared by Maillard type reaction in a controlled dry state condition)60 0C, 75% relative humidity, pH:8 for 1, 3, 5 and 7 days(. The formation of glycoconjugates was confirmed by sodium dodecyl sulphate polyacrylamide gel electrophoresis)SDS-PAGE(and gel filtration chromatography. Browning intensity, 1,1 Diphenyl 2 picryl hydrazyl (DPPH(and hydroxyl radical scavenging activity and reducing power measured their antioxidant properties. Browning and intermediate products, as monitored by absorbance at 420 nm, sharply increased with conjugation. DPPH and hydroxyl radical scavenging activity increased with increasing incubation time, this improved free radical scavenging activity mediated by antioxidant maillard reaction products. Reducing power of conjugates was remarkably increased compared with the control sample. The results demonstrated that the Maillard type soy protein-maltodextrin products can be used as an effective natural antioxidant.