Physicochemical characterization and oxidative stability of fish oil encapsulated in an amorphous matrix containing trehalose

Fish oil with 33% omega-3 fatty acids was microencapsulated by spray-drying in a matrix of n-octenylsuccinate-derivatized starch and either glucose syrup or trehalose. Samples showed no difference in physicochemical properties as determined by measurement of particle size, oil droplet size, true density and BET surface. Upon storage at low relative humidity, lipid oxidation was decreased in trehalose containing samples indicating that in the amorphous state trehalose is a more suitable wall material for microencapsulation than glucose syrup. The retarded oxidation of trehalose containing samples may be attributed to the unique binding properties of trehalose to dienes. At 54% relative humidity, a rapid oxidation of the microencapsulated oil was observed upon crystallization of trehalose, which limits the range of applications to products to be stored at low humidity.