Characterization of acetylated starch nanoparticles for potential use as an emulsion stabilizer

To overcome the low production efficiency of Pickering emulsion stabilizers prepared from starch, alcohol precipitation and surface modification were applied in this study. Spherical starch nanoparticles (StNPs) (247.90 +/- 1.96 nm) were prepared through nanoprecipitation. The StNPs were surface-esterified to produce starch nanoparticle acetate (StNPAc), and the physicochemical changes of the products were investigated. The contact angle (>89.56 degrees +/- 0.56 degrees) of StNPAc (degree of substitution, 0.53) was maintained for over 30 min. The results showed that the hydrophobicity of the StNPs was improved by shielding the surface hydroxyl groups via acet-ylation. StNPAc was also used to produce emulsions for further evaluation of their feasibility as Pickering emulsifiers. Oil-in-water (3:7, v/v) emulsions containing 1.5 wt% StNPAc were stabilized for over 35 days without creaming. Thus, StNPAc exhibited better emulsifying capacity and storage stability than StNPs. There-fore, hydrophobic starch nanoparticles obtained by acetylation are promising stabilizers for surfactant-free Pickering emulsions.

Automated summary

To improve the production efficiency of Pickering emulsion stabilizers prepared from starch, this study applied alcohol precipitation and surface modification. Spherical starch nanoparticles were prepared through nanoprecipitation and then surface-esterified to produce starch nanoparticle acetate. The results showed that the hydrophobicity of the starch nanoparticles was improved by acetylation, and the starch nanoparticle acetate exhibited better stability as an emulsifier.