Impact of Emulsification Time and Concentration of Modified Starch Nanoparticles on Pickering Stability

Abstract

The modification of the cassava native starch by heat-moisture treatment (HMT) followed by nanoprecipitation can be worthwhile for obtaining stabilizers of Pickering emulsions as highly stable emulsions and clean label products can be produced. In this study, Pickering emulsions stabilized by different concentrations of modified starch nanoparticles (HSNP), and various emulsification times were evaluated in terms of physical stability, rheological properties (flow curves) and microstructure. All emulsions produced with lower concentrations of HSNP (0.8 and 2.4wt%) destabilized within 24 h, and the emulsions stabilized with 3 and 4wt% HSNP, regardless of emulsification time, remained stable for up to 14 days. As the HSPN concentration increased, the interface became denser, preventing or delaying coalescence. The micrographs of the stable emulsion showed that the shorter the emulsification time (3 min), the larger the average droplet size. The Power Law model was well adjusted to the experimental data (shear stress vs shear rate) (R2 = 0.996), and the model constants (pseudoplasticity and consistency index) increased as HSNP concentration increased and emulsification time decreased. Physically modified starch nanoparticles were used as stabilizer of the Pickering O/W (oil in water) emulsion, and the results demonstrate that the microstructure and the rheological properties of these emulsions can be adjusted by particle concentration and emulsification time.