Optimisation of the complex coacervation between canola protein isolate and chitosan

Abstract

The complex coacervation phenomenon between canola protein isolate (CPI) and chitosan (CS) was studied. CPI was extracted in the laboratory from canola meal and used in this study. The factors affecting the yield of CPI-chitosan complex coacervates such as CPI-to-chitosan ratio, pH and strength of the electrostatic interaction (SEI) were investigated. The thermal characteristics of the un-cross-linked and transglutaminase cross-linked complex coacervates were also determined. The optimum complex coacervation between CPI and CS occurred at the CPI-to-chitosan mass ratio of 16 and the pH range of 5.8–6.2. The peak denaturation temperature and the denaturation enthalpy of CPI in CPI-chitosan complex were higher than those of the uncompleted or free CPI indicating that the complexation made the CPI more thermally stable. The thermal stability of the coacervates was further enhanced when cross-linked with transglutaminase. The increased thermal stability of CPI in CPI-chitosan coacervate indicated that CPI-chitosan coacervates would be suitable for encapsulation of thermally sensitive food and pharmaceutical ingredients.