Characterizations of Pickering emulsions stabilized by starch nanoparticles: Influence of starch variety and particle size

- Starch nanoparticles with different sizes (<100, 100-220, >220 nm) were prepared.
- The nanoparticles with a medium size of 100-220 nm have a near-neutral wettability.
- Emulsions using medium-sized nanoparticles have better stability than the others.
- The Pickering emulsions were stable against temperature and sodium chloride.

Pickering emulsions were first successfully fabricated by different types and sizes of corn, tapioca, sweet potato, and waxy corn starch nanoparticles as stabilizers. Photography, optical microscopy, confocal laser scanning microscopy, and rheology measurements were used to characterize Pickering emulsions stabilized by various starch nanoparticles. The results showed that tapioca, sweet potato, and corn starch nanoparticles were appropriate for Pickering emulsion stabilization because the three nanoparticles have nearly neutral wettability (θow ∼90°). Confocal microscopy revealed that intact and thick nanoparticle shells coated the surface of oil droplets. The Pickering emulsions stabilized by sweet potato and corn starch nanoparticles with a diameter that ranged from 100 to 220 nm had better stability than those with a diameter either less than 100 nm or more than 220 nm. These results suggested that starch nanoparticles could be used as promising particulate emulsifiers to fulfill the demands of Pickering emulsions with stable characteristics.