Chitin Pickering Emulsion for Oil Inclusion in Composite Films

A film containing a stable and well-dispersed hydrophobic phase in a surfactant-free bio-based hydrophilic matrix is proposed. In this study, an aqueous suspension of rod-like chitin nanocrystals (ChiNCs), mixed with paraffin oil, form an oil-in-water Pickering emulsion with a droplet diameter of 3 μm. These emulsions mixed with a 5 wt% starch solution formed homogeneous composite films by solvent casting. Various amounts of emulsion were incorporated, leading to self-supported films with a volume of oil as high as 45 vol%, with less than 1% of ChiNCs. This model inclusion system leads to droplets homogeneously dispersed throughout the composite films, as revealed by microscopy (SEM and CLSM) with mechanical properties controlled by the matrix. Finally, the droplets were easily released from the matrix by enzymatic hydrolysis. This easy-to-implement transparent film proved to be a good candidate when it is desirable to disperse a poor water-soluble component in a hydrophilic edible matrix.