Abstract:

Spray drying was used to prepare evening primrose oil (EPO) microcapsules for four different formulas. The
properties of microcapsules were determined by surface oil content, encapsulation efficiency, microcapsule particle size
and surface morphology. The results indicated that EPO microcapsules prepared with wall materials consisting of starch
octenylsuccinate (OSA) and maltodextrin (MD) possessed a low surface oil content, high encapsulation efficiency, small
microcapsule particle size and smooth surface. The analysis of fatty acid composition and contents showed that the
major functional components linoleic and γ-linolenic acid had no significant change before and after microencapsulation
of EPO with OSA-MD as the wall materials. When MD as one of the wall materials of microcapsules was marked by
N-methylisatoic anhydride, the inner structure of EPO microcapsules was observed by confocal laser scanning microscopy.
The microcapsules were spheres with a single-core structure and MD was uniformly distributed in the wall.

Key words: evening primrose oil, microcapsule, properties, fatty acid, microstructure