Abstract:

In this paper, citral microcapsules were prepared using β-cyclodextrin as wall material by emulsification.
The yield and microencapsulation efficiency of microencapsulated citral were investigated as functions of solid content,
emulsifier content and core-to-wall material ratio. The response surface methodology was employed to optimize the three
process parameters. A quadratic polynomial regression model was established which was found to be highly significant
and have a correlation coefficient of 0.966 1. The optimized experimental conditions were: solid content, 26%; emulsifier
content, 0.8%; and core-to-wall material ratio, 1:4, giving a yield of 78.8% in validation experiments. Meanwhile, the
sustained-release properties of microcapsules were investigated by comparison with those of the free citral. The results
showed that microencapsulation could slow down the release of citral. The release course of the microcapsules could be
fitted well with the Avrami equation.

Key words: citral, β-cyclodextrin, microcapsule, response surface methodology, sustained release