Physicochemical and emulsifying properties of whey protein isolate (WPI)-polydextrose conjugates prepared via Maillard reaction

In this study, whey protein isolate (WPI) and polydextrose (PDX) were used to produce WPI-PDX covalent conjugates via dry-heating Maillard reaction, and their characteristics and functional properties including abilities to emulsify and stabilise the corn germ oil/water emulsions were measured. Compared with WPI alone, the WPI-PDX conjugates had higher water solubility and DPPH radical scavenging ability, and the derived emulsions exhibited good storage stability over 60 days prepared under these conditions: reaction time 24 h, conjugate concentration 4-6%, oil fraction ratio 0.6 and emulsion system pH 3-8. Further, we found that the emulsion possessed the best storage stability under the condition of 4% WPI-PDX conjugates and 0.6% oil fraction. These results provide a potent to prepare a beneficial Maillard conjugation following an optimised reaction condition and highlight the potential use of WPI-PDX conjugates as the emulsifier in food industry.