Fabrication of Zein/Persian Gum Particles Under the Effect of pH and Protein:Gum Ratio and Investigating Their Physico-chemical Properties

Hydrophobic interactions between zein nanoparticles and thus extensive aggregation limit their diverse applications in food and pharmaceutical industries. In this research, water-soluble portion of Persian gum (WPG), as an emerging polysaccharide with appropriate properties and high availability, was used to increase the zein particles' stability. Zein/WPG composite particles were fabricated by anti-solvent method under the effect of pH (3-7) and protein:gum ratio (10:1-1:2) and then their properties were investigated. The average size ranged from 218.6 nm for mixed particles at 1:1 protein:gum ratio and pH 3 to 7.53 mu m for zein particles at pH 5. FT-IR spectroscopy confirmed the interaction between two biopolymers and TEM micrographs revealed a core-shell morphology in composite particles which made them much less prone to aggregation due to repulsive forces. Zeta potential result showed higher stability of particles in the presence of WPG. Incorporating WPG and pH reduction caused higher fluorescence emission at 303 nm. The presence of WPG increased the relative viscosity and the highest viscosity values were measured at pH 5 for both control zein and zein/WPG particles. The protein:gum ratio was more effective than pH on viscosity. Based on the obtained results composite samples at 1:1 and 1:2 protein:gum ratio and pH 4 showed better stability for further application. The results of this study can be used for fine-tuning nanoparticles' characteristics made from prolamins and anionic polysaccharides for different applications like encapsulation and interfacial stabilization.