Abstract: In this paper, the effect of stirring speed on morphology change of coacervated orange oil microcapsules during preparation process was investigated. Meanwhile, the effect of loading amount of microcapsules on release rate was also explored. The results showed that the coacervated microcapsules possessed spherical multinuclear structure and the particle size exhibited a gradual decrease with increasing stirring speed from 200 to 600 r/min. The coacervated microcapsules remained spherical and multinuclear structure at a stirring speed ≤ 400 r/min during gelation and hardening phases. Otherwise, the irregular coacervated microcapsules were observed at higher stirring speed. As the stirring speed rose, the loading amount of microcapsules also exhibited an obvious increase and the particle size revealed an obvious reduction, thus resulting in the decrease in release rate of the coacervated microcapsules. Therefore, the optimal stirring speed was 400 r/min for coacervated spherical multinuclear orange oil microcapsules during the preparation process, which could provide excellent slow-released characteristics.

Key words: microcapsule, coacervation, orange oil, morphology, release