OXIDATIVE STABILITY OF FISH-OIL INCLUDED IN A MICROEMULSION

Handling and storage of polyunsaturated lipids is a difficult problem due to oxidation. Oxidation products cause reduction in sensoric quality and can also have negative physiological effects, all of which obstruct the use of otherwise nutritionally important compounds. Therefore it is important to find techniques to prevent this quality deterioration. It is shown in this work that the oxidation of a fish oil can be decreased if the oil is transformed into a microemulsion with ascorbic acid and alpha-tocopherol used as antioxidants. Tocopherol will be localized in the hydrocarbon chain region whereas ascorbic acid is accumulated in the polar parts of the microemulsion. ''Packaged'' in this way the oxidation of the oil is retarded. The peroxide and anisidine values are both drastically decreased when compared to a pure fish oil, which has been demonstrated by keeping samples at 40-degrees-C for 18 days. Furthermore an improved effect was seen when ascorbic acid was solved in glycerol instead of in water.