Abstract: In this study, starch ester nanoparticles which could stabilize food-grade Pickering emulsions were successfully prepared by the combined use of alcohol sedimentation and octenyl succinic anhydride (OSA) esterification. The particle size, zeta potential, optical microscopy, and fluorescence microscopy were used as indicators to study the stability of Pickering emulsions versus nanoparticle content, pH and ionic strength. The results showed that the zeta potential of nanoparticles were changed to some extent with pH and ionic strength. The lowest absolute value of zeta potential was observed at extreme pH or low ionic strength. This study showed that the Pickering emulsion was more stable with 2.0 g/100 mL starch ester nanoparticles. In addition, stable Pickering emulsions could be obtained with a KCl concentration of 0.005 mol/L at pH 6.0. In this system the diameters of the oil droplets were the smallest of all emulsions and the oil droplets were not prone to aggregation, making the Pickering emulsion the most stable.

Key words: corn starch, nanoparticles, esterification reaction, food-grade Pickering emulsion, stability