Impact of the type of emulsifier on the physicochemical characteristics of the prepared fish oil-loaded microcapsules

Fish oil microcapsules were successfully prepared from fish oil-in-water emulsions using chitosan as shell material and anionic surfactants sodium dodecyl sulphate (SDS), sodium dodecylbenzenesulfonate (SDBS), sodium cholate (cholate), and sodium deoxycholate (DOC) as emulsifiers. The type of emulsifier influenced the physicochemical characteristics of the prepared microcapsules to different extents. The microcapsules formed with DOC showed the least mean effective diameter (MED) of 500 nm. Emulsion formed with DOC exhibited the smallest MED of 100 nm. The emulsions showed negative zeta potential values which became positive after encapsulation with chitosan. The surfactants showed little influence on thermal stability. Microcapsule suspensions showed creaming over storage. Fish oil at higher loading in SDS microcapsules showed higher primary and secondary oxidation. All microcapsules showed sustained release but the values varied depending upon the surfactants. The emulsion and microcapsules formed with DOC showed better morphology and stability despite its lower loading and encapsulation efficiency.