Microencapsulation and oxidative stability of spray-dried fish oil emulsions

Emulsions of menhaden oil and sodium caseinate (NaCas) incorporating carbohydrates of varying dextrose equivalence (DE) were spray-dried to yield encapsulated fish oil powders. The effects of carbohydrate DE (5.5-38), core/wall ratio and NaCas/carbohydrate ratio on microencapsulation efficiency (ME) and oxidative stability of spray-dried emulsions were examined. The effect of alpha-tocopherol or Trolox C addition on the oxidative stability of herring oil emulsions and powders was also determined. ME of fish oil powders was greater than 90% in most cases. Peroxide value (PV) of menhaden oil powders decreased on increasing the DE of carbohydrates. PV of menhaden oil powders increased as core/wall ratio increased from 0.33-1.0. NaCas/DE 28 ratio did not affect PV values of powders. The addition of alpha-tocopherol or Trolox C decreased PV throughout the storage period; this effect was most pronounced for alpha-tocopherol added to the oil at a concentration of 100 ppm. Addition of alpha-tocopherol delays the onset of oxidation in stored fish oil powders.