Preparation and Characterization of Microcapsules by Heat Treated Myofibrillar Protein Coacervation

Myogenic fibrin (MP) extracted from Tilapia (Oreochromis niloticus) after heat treatment (HMP) was explored as a novel encapsulant for microencapsulation of corn oil together with sodium alginate (SA) and chitosan (CS), and its performance was characterized using ultrasonic coalescence. The results showed that at 2.5% sodium alginate, 3.0% HMP content and 30% corn oil, the emulsion had small and uniform particle size with high emulsification stability. The average particle size of microcapsules after ultrasonic recondensation was 88.74±2.60 μm while the encapsulation rate was 82.59%±1.44% under the following conditions: 1.2% CS, SA:CS mass ratio of 1:1, and 5.0% calcium chloride. The microcapsules had irregular shapes and undulating surfaces, and the results of infrared spectroscopy and X-ray diffraction indicated that CS and SA formed the dense shell of microcapsules together with HMP due to electrostatic binding. Results from DSC showed that HMP microcapsules had a degree of thermal stability, and the microencapsulation significantly reduced the POV and TBA values of oil during storage, which effectively slowed down the oxidation process. The release of free fatty acids (FFA) from HMP microcapsules was 92.67% during the whole simulated digestion phase with a greater amount released during the intestinal digestion phase, indicating that microencapsulation had a retarding effect on the release of core material. This study shows that HMP compounded with sodium alginate and chitosan is feasible for microencapsulation and protection of bioactive substances, and hence expanding the applications of HMP microgel particles.