ORIGINAL PAPER One-Step Extraction and Concentration of Polyunsaturated Fatty Acids from Fish Liver J. L. Guil-Guerrero Æ J. C. Lo ´pez-Martı´nez Æ M. A. Rinco ´ n-Cervera Æ P. Campra-Madrid Received: 23 May 2006 / Accepted: 12 January 2007 / Published online: 7 February 2007 Ó AOCS 2007 Abstract The fatty acids (FA) eicosapentaenoic acid (20:5x-3; EPA) and docosahexaenoic acid (22:6x-3; DHA), which have several health benefits, have been concentrated from mako shark liver (Isurus oxyrin- chus). The process was carried out in one single step, in which fish liver oil was simultaneously extracted, saponified and concentrated. Additionally, the poly- unsaturated fatty acids (PUFA) concentrate was win- terized to crystallize the remaining saturated FA, resulting in a further increase in the concentration of DHA and EPA. Two variables, temperature and water concentration in the saponification mixture, were optimized to increase the concentration of x-3 PUFA. Best results were obtained at 12 °C and 0% water content in the mixture, obtaining 17.8% purity and 77.6% yield of EPA; DHA purity and yield were 33.3 and 82.2%, respectively. Keywords Mako shark  Isurus oxyrinchus  Eicosapentaenoic acid  Docosahexaenoic acid  x-3 PUFA concentration  Oil fractionation  Fish liver oil Introduction Health benefits of fish oils consumption are related to their high polyunsaturated fatty acid (PUFA) levels, especially x-3 family. Eicosapentaenoic acid (20:5x-3; EPA) and docosahexaenoic acid (22:6x-3; DHA) are two x-3 PUFA that have been investigated for their role in human health; they are abundant in fish (mackerel, salmon, mako shark, sardines...) and mic- roalgae oils. Their absence in a normal diet may con- tribute to the development of a wide variety of diseases, such as coronary heart disease [1], stroke [2], hypertension [3], cardiac arrhythmias [4], diabetes [5], an inadequate development of nervous and reproduc- tive systems [6], and several inflammatory disorders, such as Crohn’s disease [7]. The methods used to concentrate PUFA from fish oil are commonly based on the differences in the polarity and/or spatial configuration of the FA. This way, PUFA can be separated according to their degree of unsaturation [8]. Some common procedures em- ployed to obtain PUFA concentrates are enzymatic purification [9] and urea complexation [10]. Never- theless, the urea complexation method should be avoided for human consumption because of the re- ported production of two potent carcinogens, ethyl- or methyl-carbamates [11]. Argentated silica gel chro- matography is another common procedure to obtain higher purities of EPA and DHA [12, 13]. The sodium salts of the FA can be separated according to their solubility differences in ethanol [14]. The procedure is based on the solubility differences of FA sodium soaps in ethanol at ambient temperature, so that the higher the number of double bonds, and the shorter the chain length for the same degree of un- saturation, the higher the solubility of a given FA. By this method, PUFA concentrates containing approxi- mately twice the amount of EPA and DHA than crude oil could be obtained from fish oil [15], and seed oil PUFA concentration has also been carried out in a J. L. Guil-Guerrero (&)  J. C. Lo ´pez-Martı´nez  M. A. Rinco ´ n-Cervera  P. Campra-Madrid A ´ rea de Tecnologı´a de Alimentos, Universidad de Almerı ´a, 04120 Almerı´a, Spain e-mail: jlguil@ual.es 123 J Amer Oil Chem Soc (2007) 84:357–361 DOI 10.1007/s11746-007-1041-9