Ultrasonic Synthesis of Zein Protein Microcapsules: Stability, Morphology and Curcumin Inclusion Studies by Optical Spectroscopy and Microscopy Experiments

Zein protein (ZP) is the major storage protein of corn (maize). It is safe, biodegradable, edible, and characterized by unique amphiphilic and self-assembly properties. We exploited these properties to prepare stable ZP microcapsules by oil-in-water ultrasound-assisted emulsification. The opti-mal experimental conditions were determined in terms of the sonication frequency, applied acoustic power, sonication time, protein concentration and temperature. The morphology and stability of ZP microcapsules were characterized by optical spectroscopy and microscopy tech-niques. We found that a thick ZP outer layer protects the inner oily phase from internal/external diffusion, and enables the microencapsulation of Curcumin, a very active anti-inflammatory and nutraceutical agent.