Impact of whey protein isolates and concentrates on the formation of protein nanoparticles-stabilised Pickering emulsions

Whey protein nanoparticles (NPs) were prepared by heat-induced method. The influences of whey protein isolates (WPIs) and concentrates (WPCs) on the formation of NPs were first investigated. Then Pickering emulsions were produced by protein NPs and their properties were evaluated. After heat treatment, WPC NPs showed larger particle size, higher stability against NaCl, lower negative charge and contact angle between air and water. Dispersions of WPC NPs appeared as higher turbidity and viscosity than those of WPI NPs. The interfacial tension of WPC NPs (similar to 7.9mN/m at 3wt% NPs) was greatly lower than that of WPI NPs (similar to 12.1mN/m at 3wt% NPs). WPC NPs-stabilised emulsions had smaller particle size and were more homogeneous than WPI NPs-stabilised emulsions. WPC NPs-stabilised emulsions had higher stability against NaCl, pH and coalescence during storage.