Chitooligosaccharide assisted in the construction of pickering high internal phase emulsion near the isoelectric point of porcine plasma protein

Abstract

Protein-based emulsion products always be challenged due to destabilize the emulsification at the pH range near isoelectric point (pI) of the protein. Herein, chitooligosaccharide (COS) was successfully used to assist porcine plasma proteins (PPP) to construct the high internal phase emulsions (HIPEs) near pI of PPP, and the characteristics and mechanism of the HIPEs was investigated. Particle size of oil droplets in the HIPEs reduced significantly by adding only 0.25% COS, and the PPP-COS composite HIPEs exhibited excellent performance characteristics near pI of PPP, i.e., pH 5.0, including appearance, particle size, apparent viscosity, modulus, 3D printing and stability. PPP and COS combined to form micro-size particles with many positive charges at pH 5.0, and a strong adsorption between PPP and COS was observed at the pH by quartz crystal microbalance with dissipation (QCMD). The pI of PPP shifted increasingly by about 0.5 along with addition of COS, and so no precipitates were formed at pH 5.0 according to the optical density. Hydrophobic interaction and hydrogen bond could be the main forces between PPP and COS based on interaction analysis. The work provided an excellent compound emulsifier with some bioactivities to stabilize the HIPEs near pI of the protein.