Comparative study on properties of the microencapsule of perilla oil entrapped with different microencapsulation methods

The microcapsule of perilla oil was prepared by spray-drying and freeze-drying technology by using the starch octenylsuccinate as the wall material. The best technological conditions were achieved by carrying out the research on solid content, the mass ratio of core material and wall material, homogenization time, homogenization rate and emulsification temperature. The optimization preparation conditions were as follows: solid content 30 %, the mass ratio of core material and wall material 1 ∶ 4, homogenization time 2min, homogenization rate 16000r/min and emulsification temperature 50℃. The effects of microencapsulation methods on encapsulation efficiency, storage stability, sensory evaluation, and the configuration of surface were studied comparatively. The microcapsules encapsulation efficiency (MEE) of perilla oil could reach at 98.86% by spray-drying preparation and reach at 76.24% by freeze-drying preparation. Spray-dried microcapsules appeared regular spherical, good fluidity, fine texture, easy to dissolve. Smooth surface and dense structure so as to reduce the chance of contact with the outside world, slow down the oxidation rate, prolong storage period. However, freeze-dried microcapsules were porous, showing irregular lumps, poor mobility and high moisture content. It was concluded that the properties of powdered oil produced by spray-drying preceded those produced by freeze-drying, and the starch octenylsuccinate was suitable for preparation of spray-drying microencapsulated perilla oil with respect to long-term storage.