Shorter Chitin Nanofibrils Enhance Pickering Emulsion Stability: Role of Length and Interfacial Network

The structure-property relationship of chitin nanofibrils (NCh) with tailored lengths (L-, M-, S-NCh) and their efficacy in stabilizing Pickering emulsions were systematically investigated. The nanofibrils, produced via high-pressure homogenization and ultrasonication (20 or 60 min), were characterized by transmission electron microscopy (TEM). Emulsion stability was predominantly governed by nanofibril length and concentration, with S-NCh (shortest) exhibiting superior performance, as evidenced by its minimal creaming index, smallest droplet size (1.18 μm at 0.5%), and homogeneous microstructure observed by confocal laser scanning microscopy (CLSM). A critical stabilizer concentration of 0.05% was identified, below which instability occurred due to insufficient interfacial coverage. Rheological analysis confirmed shear-thinning behavior and solid-like viscoelasticity at high frequencies. CLSM microstructural observations directly confirmed nanofibril adsorption at the interface and the formation of a continuous network between droplets, elucidating the stabilization mechanism. These findings demonstrate that shorter chitin nanofibrils provide a marked improvement in emulsion stability, offering a superior biomass-derived alternative for the design of stabilizers in food and pharmaceutical applications.