High internal phase oil-in-water Pickering emulsions stabilized by chitin nanofibrils: 3D structuring and solid foams

Chitin nanofibrils (NCh, ~10 nm lateral size) are produced under conditions that are less severe compared to those for other biomass-derived nanomaterials and used to formulate high internal phase Pickering emulsions (HIPPEs). Pre-emulsification followed by continuous oil feeding facilitates a “scaffold” with high elasticity, which arrests droplet mobility and coarsening, achieving edible oil-in-water emulsions with internal phase volume fraction as high as 88%. The high stabilization ability of the rod-like NCh originates from the restricted coarsening, droplet breakage and coalescence upon emulsion formation. This is the result from (a) irreversible adsorption at the interface (wettability measurements by the captive bubble method) and (b) structuring in highly interconnected fibrillar networks in continuous phase (rheology, cryo-SEM, and fluorescent microscopies). Owing to the fact that the surface energy of NCh can be tailored by pH (protonation of surface amino groups), emulsion formation is found to...