Preparation and characteristics of tea water-insoluble protein/chitosan composite particles

The emulsifying properties of tea water-insoluble protein particles (TWIPs) are insufficient to expand their applicability in food emulsifying systems. This study aimed to explore the emulsification characteristics and application of tea water-insoluble protein/chitosan composite particles (TCPs). Scanning electron microscopy showed the TWIPs were tightly coupled with chitosan (CS). The transform of secondary structure and amino acid residues were beneficial to the formation of TCPs and improvement of emulsification performance. Increasing the CS concentration improved the viscoelasticity, as verified by rheological property, and decreased the droplet size of Pickering emulsions (PEs) at a TWIP-CS mass ratio of 50:50. In addition, when the fixed TWIP-CS ratio was 50:50, the TCPs concentration of 0.5% favored the formation of bovine bone white soup with extraordinary emulsification stability ( p < 0.05). In conclusion, the emulsification property of TWIPs was improved at a TWIP-CS ratio of 50:50, which was also verified in PEs and bovine bone white soup. This work provided a theoretical basis for the development and further deep processing of tea by-products, and broadened the application of tea protein in liquid emulsification system. • Tea water-insoluble protein/chitosan composite nanoparticles were obtained as stabilizers; • The emulsification property of TWIPs was improved at a TWIP-CS ratio of 50:50. • Pickering emulsions (PEs) were stabilized via TWIP-CS composite particles (TCPs); • Droplet size of PEs stabilized with TCPs decreased significantly compared to TWIPs; • The emulsion stability of beef bone white soup prepared by adding 0.5% TCPs was higher.