Zein is biodegradable hydrophobic protein and is conventionally prepared as dispersible nanoparticles with the antisolvent precipitation method. The process involves dissolving zein in 55-90% aqueous ethanol and then shearing the stock solutions into deionized water. The objective of the present work was to develop a new way to produce zein-based nanoparticles based on the finding that gum Arabic (GA) was able to dissolve in 0-90% aqueous ethanol. Results from dynamic light scattering show that the size distribution of zein or GA alone in 70% aqueous ethanol was multimodal but shifted to a monomodal peak centered below 400 nm after mixing 70% aqueous ethanol of zein with that of GA within a range of pH from 7.0 to 12.0, indicating the formation of zein-GA binary nanocomplexes. The mean hydrodynamic diameter (D<sub>h</sub>) of nanocomplexes was further affected by the amount of GA. The binary nanocomplexes with equal masses of zein and GA had a D<sub>h</sub> of 203.2±1.27 nm and had the minimun polydispersity index of 0.07 at pH 8.0. The images of transmission electron microscopy show that the core-shell microstructure was formed for zein-GA binary nanocomplexes. This was further confirmed in scanning electron microscopy that showed zein as a core was surrounded by GA as a shell. In addition, the incorporation of GA resulted in significantly secondary structural changes of zein. The fluorescence intensity of zein was obviously decreased due to the fluorescence quenching in the presence of GA. The findings may provide a new insight for the process of fabricating zein-based nanoparticles, which would have potential applications such as constructing delivery systems for bioactive compounds.

Preparation and characterization of zein and gum arabic binary nanocomplexes in aqueous ethanol

2019 Fall National Meeting

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