Preparation and Characterization of Yak Ghee Microcapsules

In order to improve the oxidation resistance of traditional yak ghee, extend the shelf life, the yak ghee was embedded in gum Arabic and gelatin by complex coacervation method to prepare yak ghee microcapsules. The optimal preparation technology was obtained via single factor and orthogonal experiment with embedding rate as an index, and the physical and chemical properties, morphology structure, stability and properties in simulate gastrointestinal digestion were also investigated. The results showed that the best parameters of yak ghee microcapsules were as follows: Core-to-wall ratio was 1:1.5, mass fraction of wall material was 1.5%, complex coacervation pH was 4.2, the complex coacervation temperature was 40 ℃, and encapsulation efficiency of microcapsules was 81.39%. The average particle size, moisture content, solubility and angle of repose were 19.728 μm, 3.62%, 96.48% and 37.7°, respectively. Scanning electron microscope and fourier transform infrared spectroscopy showed that the surface of yak ghee microcapsules was smooth, the morphology was irregular, and yak ghee was successfully embedded in wall materials. Differential scanning calorimeter and thermogravimetric analysis proved that yak ghee microcapsules possessed good thermal stability. In addition, the release of yak ghee microcapsules could be controlled in simulated gastric and intestinal fluid, and the release rate in simulated intestinal fluid was 99.74%. Storage experiments exhibited that microencapsulation could slow down the oxidation rate of yak ghee and prolong the shelf life. This study will help provide theoretical basis for improving the bioavailability of yak ghee.