Microencapsulation properties of two different types of n-octenylsuccinate-derivatised starch

Aim of the present study was to evaluate the suitability of two different types of n-octenylsuccinate-derivatised starch, which significantly differed in viscosity, for microencapsulation of a fish oil rich in long-chain polyunsaturated fatty acids. Stable feed emulsions for microencapsulation could be prepared with both types of n-octenylsuccinate starch, however at a high oil load (50%), a low pH (pH 4.5) of the emulsion was crucial for emulsion stability. At 50% oil content, lower oil droplet size in reconstituted spray-dried emulsions and lower content of non-encapsulated oil was reached by low viscosity starch compared to medium viscosity starch. Conjugated dienes were significantly increased in samples with a high oil load and 40% starch indicating that to a certain degree lipid oxidation already occurred in these samples during the drying process. Finally, moderate spray-drying conditions must be considered as advantageous, since ballooning of the particles and lipid oxidation during spray drying were limited compared to drying at high spray-drying temperatures.