Zein is a group of alcohol-soluble maize proteins and is typically dissolved in 70e80% aqueous ethanol
before dispersion into water to precipitate zein as nanoparticles, which can simultaneously encapsulate
various lipophilic compounds co-dissolved in aqueous ethanol. However, strategies are needed to prevent
the precipitation of hydrophobic zein nanoparticles at a wide pH range and the use of flammable
ethanol in the industrial production. The objective of this work was to replace ethanol with nonflammable
propylene glycol to prepare zein nanoparticles and stabilize nanoparticles using gum arabic (GA).
Nanoparticles smaller than 200 nm were produced using a stir plate, and GA prevented their precipitation
at pH 3.0e8.0. Both electrostatic and hydrophobic interactions contributed to the adsorption of GA
on zein nanoparticles, with the former being more significant at a lower pH corresponding to a higher
surface load. Encapsulation of peppermint oil in zein nanoparticle-GA complexes did not significantly
change particle dimension and dispersion stability. The gradual release of peppermint oil from freezedried
samples was observed at pH 2.0e8.0,
reaching complete release in a shorter time at a lower pH.
The established method may enable