Oil-in-Water Zein Protein/Soybean Oil Microcapsules from Ultrasound-Assisted Emulsification: Stability, Morphology and Curcumin Inclusion/Release Studies

Zein (ZP) is the major storage protein of corn (maize). It is safe, biodegradable, edible, and characterized by unique amphiphilic and self-assembly properties. These proper-ties were exploited to prepare ZP/Soybean Oil (SO) filled microcapsules by ultra-sound-assisted emulsification of oil in water (o/w) solutions under optimal experi-mental conditions. The morphology and stability of o/w ZP/SO microcapsules were characterized by optical spectroscopy (electronic circular dichroism, fluorescence), dynamic light scattering, and bright-field, laser confocal fluorescence and scanning electron microscopies. It is shown that ZP, due to its unique amphiphilic properties, forms a stable outer layer that protects the inner oily phase by diffusion of the confined compounds. Proof-of-principle studies on the inclusion and release of Curcumin, a very active anti-inflammatory and nutraceutical substance, from ZP/SO microcapsules under temperature and pH stimuli are also reported.