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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 phosphatidylethanolamine). 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.

alpha-Linolenic acid (ALA) was incorporated at 28% into the sn-1 position of egg-yolk phospatidylcholine using Novozyme 435 in one-step transesterification process. Using phospholipase A(2) in a two-step process gave 25% incorporation of ALA into the sn-2 position.

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