Encapsulation of fish oil and essential fatty acids by spray drying

Fish oil and essential fatty acids are considered significant in functional foods. Polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (20 : 5) and docosahexaenoic acid (22 : 6) in fish oil are prone to oxidative damage. The encapsulation of fish oil by spray drying is a useful method to stabilize fish oil by reducing contact with oxygen. In this review, kinetic analyses of oxidation of fish oil and fatty acids in bulk and emulsion systems and encapsulated fish and krill oils in spray-dried powders were reviewed. Oxidation kinetics of PUFAs could be expressed with the autoxidation equation using the fraction of unoxidized PUFA. The surface-oil ratio could be correlated with the equation 1 − (1 − 2(de/dp))3 using the ratio of oil-droplet diameter, de, to powder diameter, dp. The morphology of the spray-dried powder containing vacuoles affected the surface-oil ratio. The activation energy (Ea) could be correlated with the reconstituted oil droplet diameter of squalene powders. In the estimation of fish oil in spray-dried powder, this review showed that the model of deterioration kinetics of fish oil in the powder is very useful.