Concentration of eicosapentaenoic acid and docosahexaenoic acid from fish oil by hydrolysis and urea complexation

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from chemically or enzymatically hydrolyzed from sardine oil were concentrated by urea complexation. The enzymatic hydrolysis was effected in aqueous emulsion using five commercial lipases from Pseudomonas, three immobilized (PS-CL PS-CII and PS-DI) and two soluble lipases (AK-20 and PS-30). EPA and DHA were determined by gas-liquid chromatography as methyl esters. Results showed that an immobilized lipase preparation (PS-CI) produced the highest degree of hydrolysis for EPA and DHA (81.5 and 72.3% from their initial content in the oil) after 24 h. After complexation of saturated and loss unsaturated free fatty acids, the highest concentration of EPA (46.2%) and DHA (40.3%) was obtained using an ethanolic solution with 20% (w/w) urea and 12% (w/w) PS-Cl hydrolyzed with a 78% yield. Combination of enzymatic or chemical hydrolysis with urea complexation is a promising method to obtain highly concentrated n-3 PUFA from sardine oil. (C) 2003 Elsevier Science Ltd. All rights reserved.