US Patent 7419596 Extraction and winterization of lipids from oilseed and microbial sources

A process for purifying a lipid composition having predominantly neutral lipid components having at least one long chain polyunsaturated fatty acid is disclosed. The process employs contacting the lipid composition with a polar solvent, such as acetone, wherein the solvent is selected such that the contaminants are less soluble in the solvent than in the long chain polyunsaturated fatty acid. The process is typically conducted at cooler temperatures including about 0° C. Upon precipitation of the contaminants from the lipid composition, a separation is conducted to remove the precipitated material from the lipid composition. The long chain polyunsaturated fatty acids can include ARA, DPA, EPA and/or DHA. The process effectively winterizes lipid compositions, thereby reducing the tendency of such compositions to become hazy.