Post-self-assemble of whey protein isolation nanofibrils and its contribution to the stability of pickering emulsion

Protein nanofibrils (PNFs), as a kind of amyloid structure with high aspect ratio, ordered arrangement and high surface activity, have been applied to stabilize Pickering emulsions (PEs) and exhibit superior stability. Homogenization randomly disperses whey protein isolation PNFs (WPNFs) from 1 to 10 μm to short fibrils (SFs) of about 0.2–1 μm. These SFs have the ability to reassemble into long fibrils again in aqueous solutions at pH 2.0 and at the oil-water interface of the PEs, and this reassembly process is defined as post self-assembly, and post-self-assembled WPNFs are defined as p-WPNFs. The post-self-assembly capability could be used to explain the significantly improved stability of PNFs stabilized PEs. The SFs has high flexibility and mobility, so that they can be dispersed faster to the oil-water interface, thus having smaller and more uniform droplets; the post self-assembly of SFs at the oil-water interface improved the rigidity and elasticity of the interfacial layer. The significantly improved storage stability, freeze-thaw stability and centrifugal stability reveals the contribution of post-self-assembly of WPNFs, and the discovered post-self-assembly behavior will enlighten the development and application of PNFs in the food, pharmaceutical and cosmetic industries.