Fabrication and characterization of water-soluble phytosterol ester nanodispersion by emulsification-evaporation combined ultrasonic method

The purpose of this study was to fabricate a water-soluble phytosterol ester (PE) nanodispersion using emulsification-evaporation combined high-energy approaches (ultrasonic and microfluidization treatment). The effects of different surfactants, fabricating condition on the characterization of PE nanodispersions were investigated. Our results indicated that soybean protein isolate (SPI) was more suitable for the fabrication of PE nanodispersion than konjac gum, rice protein and sodium caseinate (NaCas). The average particle size, ζ-potential, encapsulation efficiency and loading amount of PE nanodispersion were 97.2 ± 5.0 nm, −38.9 ± 3.2 mV, 95.4 ± 0.4% and 19.1 ± 0.8%, respectively. Hydrophobic interaction played a significant role in the formation of nanodispersion. Microfluidization and high-speed shearing affected the secondary structure of SPI by breaking hydrogen bonds. Ultrasonic treatment could facilitate hydrogen bond formation, and increase hydrophobic interaction between SPI and PE. Emulsification-evaporation combined with ultrasonic method was gentler than microfluidization in the preparation of PE nanodispersion. The present method can be used to increase the water-solubility of PE and may be extended for other hydrophobic compounds.