Zein self-assembly using the built-in ultrasonic dialysis process: microphase behavior and the effect of dialysate properties

The microphase behavior at different time scales was investigated to understand the mechanism of zein self-assembly during the built-in ultrasonic dialysis process (BUDP) in this study. The results indicated that the mutual mass transfer between zein solution and dialysate changed the solvent polarity, which caused the conformational transition of zein molecules, formation of stable droplets under the ultrasonic field, and further solidification of the compact microspheres. The effects of dialysate properties on zein self-assembly were investigated. The results showed that both pH and ionic strength had a great effect on the size, zeta potential, and morphology of the obtained zein particles, where zein microspheres with a size around 1-2 mu m and zeta potential > 30 mV were obtained at pH 4-pH 8 and NaCl concentration <= 10 mM. And non-ionic Tween 60 could be used as a potential surfactant to improve the stability of zein samples through a physical combination.