Characterization and human microfold cell assay of fish oil microcapsules: Effect of spray drying and freeze-drying using konjac glucomannan (KGM)-soybean protein isolate (SPI) as wall materials

The properties of microencapsulated fish oil, prepared with spray drying and freeze-drying processes using emulsions of konjac glucomannan (KGM) and soybean protein isolate (SPI) was investigated. Comparative analysis of microcapsules showed the encapsulation efficiency of spray drying and freeze-drying were 90.10% and 83.52% respectively. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) results exhibited that microcapsules prepared with spray drying were spherical particles with a compact structure, while microcapsules prepared with freeze-drying were irregular particles with a pore-like structure. Release kinetics test further indicated retention rate of core materials for microcapsules prepared with spray drying were better than with freeze-drying. In addition, a human epithelial microfold cell (M-cell) transcytotic assay demonstrated that the M-cells had greater transport activity for the exogenous microcapsules.