Improving the stability of wheat gliadin nanoparticles – Effect of gum arabic addition

Wheat gliadin nanoparticles were prepared by antisolvent precipitation, and gum arabic (GA) was added to improve the stability of the nanoparticles. Effect of pH, gliadin/GA ratio and gliadin concentration on the gliadin-GA particles were studied by turbidimetric measurement. Spinodal lines for the GA-gliadin-solvent system were built under different pH. The influences of gliadin/GA ratio and their concentrations were represented in the diagram, thus the conditions for preparing stable composite were defined. The stability of GA-coated gliadin nanoparticles (Gliadin/GA = 1:3) was further studied compared with uncoated gliadin particles. GA-coated nanoparticles had a relatively good stability at pH 4.0–7.0 and remained a relatively low particle size with the elevated ionic strengths. They also had good thermal stability at 80 °C. Moreover, the interactions between gliadin particles and GA under different pH were further investigated. Hydrogen bonding was found to be the predominant force at pH 5.0, while hydrophobic force took charge of the formation of complex at pH 7.0. The findings are of great importance for extending the current knowledge about gliadin nanoparticles coupled with polysaccharides, thus providing valuable information for the development of gliadin-polysaccharide nanoparticles as potential nano-delivery systems.