Encapsulation of milk protein with inulin for improved digestibility

Abstract

Encapsulation is the packaging of bioactive compounds to isolate and control their release upon applying specific conditions. By using inulin as the wall material for milk protein encapsulation, it can improve the stability and reduce the rate of protein release which can be related to better digestibility. This study aims to find the best encapsulation parameters for milk protein encapsulation using inulin based on the encapsulation efficiency and evaluate the protein release by simulation of intestinal fluid in vitro. Protein encapsulation was prepared under various parameters including inulin concentration, stirring temperature and stirring speed. The encapsulation parameters were analysed by Response Surface Methodology to obtain the highest encapsulation efficiency, which was subsequently used for the analysis of particle size, zeta potential and protein release kinetics. The results showed that inulin concentration was the most significant in determining encapsulation efficiency, and the highest encapsulation efficiency (75.90%) was achieved at 0.47 % w/v of inulin concentration, stirring temperature of 35.17°C and stirring speed of 510.79 rpm. The inulin-encapsulated milk protein produced under the best encapsulation parameters had an average particle size value of 485.8 nm and zeta potential of -10.5 mV. Zero order kinetics model was most suited to describe the encapsulated milk protein release, indicating slow release of protein that may be associated with better digestibility.