EP0347509A1 — A process of extraction and purification of polyunsaturated fatty acids from natural sources

USPTO Abstract

To extract and purify polyunsaturated fatty acids, particularly EPA and DHA, without cis-trans conversion, from naturally occurring oils, such as marine animal oil and various vegetable oils, a mixture of free fatty acids is first extracted from the oil. The resulting mixture of pure fatty acids is then sub­jected to separation by means of urea complexing to remove saturated fatty acids and most mono-unsaturated fatty acids. Remaining solvent and urea are then re­moved from the filtrate which is then subjected to low temperature fractional crystallization in the presence of an organic solvent such as acetone. Substantially pure polyunsaturated fatty acids, especially EPA and DHA, can be separately precipitated by reducing the temperature of the filtrate in two steps. Alternative­ly, the volume of the filtrate is is reduced in two steps and cooled to form precipitates, which are re­moved. The final product is a mixture of substantially pure DHA and EPA.