Physicochemical Properties of Dry-Heated Peanut Protein Isolate Conjugated with Dextran or Gum Arabic

Peanut protein isolate (PPI) were conjugated with dextran or gum arabic through glycation to study the physiochemical properties of PPI–polysaccharides conjugates. Structural features, solubility as well as emulsifying properties of the two conjugates were compared. The degree of graft value of the two conjugates suggested that glycation of PPI with gum arabic took place more easily than with dextran. Glycated conjugates had better solubility and emulsifying ability than native PPI. Analysis of structural features of the conjugates suggested that their improved functional properties could be the result of less α-helix secondary structure, lower surface hydrophobicity and less compact tertiary structure. The solubility of PPI–dextran conjugates was improved for the pH range 3–9, while that of PPI–gum arabic conjugates was improved above neutral pH range. Moreover, better emulsifying ability was observed in PPI–gum arabic conjugates than PPI–dextran conjugates.