Chemical stabilization of oils rich in long-chain polyunsaturated fatty acids during storage

During the microencapsulation process, the fish oil undergoes multiple changes in its physical properties such as bulkiness and dispersibility in aqueous phase and dry matrix. Autoxidation already occurred in the first stages of the microencapsulation process itself during emulsification and spray-drying. An efficient stabilization was achieved using a ternary combination of lipophilic antioxidants, synergistic compounds and a trace metal chelator, e.g. a combination of tocopherols, rich in the δ-derivative and low in the α-derivative, with ascorbyl palmitate and lecithin. Trace metal chelation by, e.g. Citrem or lecithin in combination with ascorbyl palmitate proved to be of particular importance in the emulsion, but not during the storage of the microencapsulated oil. In the microencapsulated oil, the addition of rosemary extract rich in carnosic acid to ternary blends of tocopherols, ascorbyl palmitate and lecithin or Citrem significantly retarded autoxidation.