LETTER TO THE EDITOR Isolation of Pure Phospholipid Fraction from Egg Yolk Witold Gladkowski • Anna Chojnacka • Grzegorz Kielbowicz • Tadeusz Trziszka • Czeslaw Wawrzen ´ czyk Received: 5 March 2011 / Revised: 14 June 2011 / Accepted: 18 June 2011 / Published online: 17 July 2011 Ó AOCS 2011 Abstract The phospholipid (PL) fraction from egg yolk was isolated and purified. In the procedure applied (method 2) the egg yolk was extracted with ethanol, precipitated using acetone chilled to -20 °C and washed using acetone. The purity of the samples was checked by HPLC analysis using a Charged Aerosol Detector (CAD). The results were compared with those obtained for the phospholipid fraction isolated and purified by deoiling yolk before extraction and the precipitation of PL with acetone chilled to 4 °C (method 1). The use of acetone chilled to -20 °C to precipitate and wash the phospholipids yielded the phospholipid fraction with 100% purity (78.7 ± 0.2 of phosphatidylcholine and 21.3 ± 0.2 of phosphatidyletha- nolamine). When deoiling and the 4 °C purification process was used (method 1) 0.4 ± 0.1% cholesterol and some traces of triacylglycerols remained in the PL fraction. Keywords Phospholipids Á Lecithin Á Extraction Á Precipitation Á Charged Aerosol Detector Dear Editor: Among the biologically active lipids, the phospholipids (PL) have attracted great attention due to their unique nutritional and functional properties. Although PL are mainly used in pharmaceuticals [1–8] to a lesser degree, PL are also used in the cosmetics [9] and food [10] industries. Because of their amphiphilic character, phospholipids form microscopic vesicles consisting of an aqueous core enclosed in phospholipid layers. These vesicles or lipo- somes may be used in the encapsulation of drugs, protein or peptide antigens. Encapsulation improves delivery of these health-promoting agents to targeted tissues [11, 12] in the body. The main PL component in egg yolk is phosphati- dylcholine (PC). PC is particularly valuable nutritionally because it is the source of two important nutrients—choline and polyunsaturated fatty acids (PUFA) from the n-3 and n-6 PL family. The main commercial source of PL is soyabean lecithin. However, commercial soya lecithin, which is a by-product of oil refining, is a mixture of various lipid fractions and carbohydrates and the content of PC is only 20% [13]. PC content may be increased to about 50% by fractionation with ethanol however 50% is not pure enough for use in pharmaceutical applications. Therefore, interest in egg yolk PC or lecithin production has increased, especially if the production of PUFA enriched phospholipids may be increased through feeding modifications of laying hens [14, 15]. PC isolation and purification methods, particularly the removal of cholesterol, need to be developed and evaluated. The methods for PC isolation and purification in the literature are rather complicated and the purity of PL fraction is not satisfactory. Generally, egg yolk PL are extracted with organic solvents, especially ethanol, and then purified by removing triacylglycerols (TAG) and cholesterol. Several techniques of purifying the PL fraction have been investigated, including extraction with various solvents [16], low temperature crystallization to remove the W. Gladkowski (&) Á A. Chojnacka Á G. Kielbowicz Á C. Wawrzen ´czyk Department of Chemistry, Wroclaw University of Environmental and Life Sciences, 50-375 Wroclaw, Poland e-mail: glado@poczta.fm T. Trziszka Department of Animal Products Technology and Quality Management, Wroclaw University of Environmental and Life Sciences, 50-375 Wroclaw, Poland 123 J Am Oil Chem Soc (2012) 89:179–182 DOI 10.1007/s11746-011-1893-x