Preparation, properties and interaction of curcumin loaded zein/HP-β-CD nanoparticles based on electrostatic interactions by antisolvent co-precipitation

In this study, zein/hydroxypropyl-beta-cyclodextrin nanoparticles (ZHNPs) were synthesized using a combination of antisolvent co-precipitation and electrostatic attraction. The structural and physicochemical properties of the NPs were characterized using a variety of analytical methods. NPs with small mean diameters (143.6 nm) and strong cationic surface potentials (+62.1 mV) could be obtained at a mass ratio of zein-to-HP-β-CD of 1:1. These NPs were then used to encapsulate a model hydrophobic nutraceutical, curcumin. The results of zeta-potential, Fourier-transform infrared spectroscopy, X-ray diffractometry, and fluorescence spectroscopy measurements suggested that electrostatic, hydrogen bonding, and hydrophobic interactions were the main driving forces for NPs formation and curcumin encapsulation. The NPs had a relatively high encapsulation efficiency (89.41 %) for curcumin and improved its antioxidant activity (3.6-fold that of free curcumin) and photostability. Consequently, they could be used as effective food-grade delivery systems for low water-soluble bioactive substances.