ABSTRACT
OBJECTIVE: To optimize the preparation process of microcapsules of eucalyptus citriodora oil, and to investigate its thermal stability. METHODS: Using gelatin as the capsule materials, the microcapsules were prepared by simple coacervation. Base on single factor experiments, three factors including the concentration of gelatin, the core-wall ratio and the reaction temperature were selected to study the preparation conditions by Box-Behnken design and response surface method with its encapsulation efficiency as index. The test results were analyzed by Design-Expert 8.0.6 software. RESULTS: The optimal preparation process was as follows: gelatin solution concentration 3.27%, core-wall ratio 2.5∶1, preparation temperature 50 ℃. Under the optimized preparation process, the encapsulation rate was 67.50%, which was different from the model prediction value (65.68%) by 2.77%. The particle size was about 75 μm and relatively uniform, and the surface was relatively smooth. Moreover, thermal analysis showed that microencapsulation of eucalyptus citriodora oil could significantly increase its thermal stability. CONCLUSION: Using Box-Behnken design and response surface method to optimize the preparation process of eucalyptus citriodora oil microcapsule is accurate, effective and feasible. Microencapsulation can improve the thermal stability of eucalyptus citriodora oil.