Oral drug delivery systems are of great interest to enhance the aqueous solubility, stability, intestinal absorption of drugs and nutrients. Prolamin, the major cereal storage protein, is of special interest among these delivery system materials, due to their wide availability, low allergenicity and unique physical properties such as high hydrophobicity. However, most prolamin based delivery systems have been built using zein from maize. Due to the growing demand of plant protein delivery materials, it would be meaningful to explore new prolamin source from other cereals and compare their encapsulating properties with zein. In addition, prolamin nanoparticles usually have poor dispersibility and stability against pH and ionic strength, required simple but effective modification to improve their physical properties. Therefore, in this study, we aimed to 1) prepare delivery system using proteins from other cereal sources, especially from agro-industrial by-products, 2) characterize the encapsulation properties of them, 3) improve the physical properties of prolamin based nanoparticles by complexation with other biopolymers. Prolamins from two cereal grains (maize and proso millet) and one food industrial by-product (brewer's spent grain, BSG) were extracted and employed to develop nanoparticles. Polysaccharides including gum arabic and sodium alginate were used to complex with prolamins and fabricate composite nanoparticles with better pH/ionic stability. Curcumin, as model drug molecule, was encapsulated into these composite nanoparticles. And the release profiles of curcumin-loaded composite particles in simulated oral, gastric and intestinal fluids were studied. Zein nanoparticles showed smaller particle size and higher stability than other prolamin based nanoparticles but similar encapsulation efficiency. Curcumin encapsualted in millet prolamin nanoparticles presented a slower release rate using an in vitro gastrointestinal model. The potential of using different protein fractions from BSG has been studied. The findings in this study are useful for fabricating, optimizing and selecting prolamin-based delivery systems.

Development of cereal prolamin based nanoparticles as oral drug delivery system

2019 Fall National Meeting

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