Stability of eicosapentaenoic acid and docosahexaenoic acid in spray-dried powder of emulsified krill oil

Abstract Krill oil (KO) from Pacific krill (Euphausia pacifica) has high contents of polyunsaturated fatty acids (PUFAs) and phospholipids. This KO is very unstable due to the oxidation of PUFAs. Encapsulation prevents those PUFAs to be oxidized and prolongs the shelf-life. Emulsified KO was encapsulated with maltodextrin (dextrose equivalent = 19) and Quillaja saponin as emulsifiers. The retentions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the spray-dried powders were investigated and their stabilities in the spray-dried powder of emulsified krill oil during storage were measured in aluminum pouches at 25, 50, and 70°C. The retentions of EPA and DHA in spray-dried powders immediately after spray drying were 99% and 100%, respectively, for samples subjected to high-pressure homogenization. Those retentions after 6 months of storage at room temperature (25°C) were over 80%. However, such retentions after 6 months of storage at 50°C were approximately 5% and 0%, respectively. The retentions could be estimated using the Avrami equation.