Improvement of functional properties of peanut protein isolate by conjugation with dextran through Maillard reaction

Reaction mixtures containing peanut protein isolate (PPI) and dextran (1:1 weight ratio) were dry-heated at 60 degrees C and 79% relative humidity for 7 days. SDS-PAGE analysis indicated that PPI had become complexed with dextran to form conjugates of higher molecular weight. Arachin, accounting for 50% of peanut proteins, was hard to glycosylate with dextran, which might limit the extent of glycosylation of PPI. The thermal stability of PPI was remarkably improved by mixture/conjugation with dextran. Proteins in mixtures/conjugates might have a more compacted tertiary conformation than PPI. The protein solubility of conjugates at pH 4.5-6.0 was remarkably increased compared with the PPI/mixture. Mixture with dextran could significantly improve the emulsifying and foaming properties of PPI (p < 0.05). Conjugation with dextran could further enhance emulsifying and foaming properties of PPI. (C) 2011 Elsevier Ltd. All rights reserved.