Chitosan/gum arabic complexes to stabilize Pickering emulsions: Relationship between the preparation, structure and oil-water interfacial activity
Ni Zhang, Jing Han, Fenglian Chen, Chengcheng Gao, Xiaozhi Tang
Abstract
Chitosan (CS) was used as the cationic polyelectrolyte, and gum Arabic (GA) was used as the anionic polyelectrolyte to fabricate natural biodegradable CS/GA complexes. The relationships between the preparation, microstructure and interface activity of CS/GA complexes were explored, with aiming to tune the interface activity of CS/GA complexes. FTIR confirmed that CS and GA was combined mainly through electrostatic interaction. CS/GA mass ration, ionic strength and pH significantly affected the reaction between CS and GA and the interface activity of CS/GA complexes. All complexes were in spherical shape but with different size and aggregation degree. Low CS/GA ratio improved the yield and interface activity of CS/GA complexes. The presence of NaCl reduced the yield and interface activity of CS/GA complex. The CS/GA complexes obtained beyond the pKa of CS showed higher yield, lower interface tension and higher emulsion capacity. It was mainly related to the highest yield of particles including the CS/GA complexes and single CS particles at this pH. However, the complex prepared at pH 5.0 stabilized- Pickering emulsion showed higher stability. This suggested that the pure CS/GA complexes possessed higher interface activity than single CS particles.