Cooperative Stabilization of Pickering Emulsions by Starch and Chitin Nanoparticles: Roles of Ball-Milling, Gelatinization, Adsorption, and Viscosity Behavior

We demonstrate enhanced Pickering emulsion stabilization by modified starch nanoparticles (SNP) through their combination with chitin nanocrystals (ChNC). The effect of the biopolymer's ratio on the emulsion stabilization mechanisms was elucidated based on their role at the interface and bulk phases. The stabilization achieved with a 1:1 (SNP:ChNC) ratio surpasses that of other ratios studied, exhibiting a synergistic effect compared with neat SNP and the 10:1 and 5:1 systems. Emulsion stability was further improved by applying thermal pretreatment to the aqueous phase before homogenization. The heat-treated 1:1 emulsion maintained a consistent droplet size (∼3.4 μm) over four months, even after slow creaming. This stability is attributed to SNP adsorption at the oil-water interface, providing a mechanical barrier to droplet's coalescence, while ChNC is also present in the oil-water interface and forms a colloidal network in the continuous phase, hindering droplet's mobility and preventing Ostwald ripening. These findings expand the application of chitin as an emulsifier and address the rising demand for healthier and sustainable emulsified formulations with reduced costs.