Separation And Extraction Of Phosphatidylcholine In Duck Egg Yolk

The paper focused on egg yolk , which was ample and not well developed .Recently scientists have been paid more attention to the phospholipid. Compared with many extraction methods of phospholipids from egg yolk, we choose enzymatic hydrolysis egg yolk and synchronous extraction of phospholipid and triglyceride by organic solvent, aimed to find a safe, cheap and effective way .First, a determination phospholipids method was developed. It is useful to determine phosphorus to know the equivalent phosphatide content in the egg yolk powder. Then Ultraviolet-obvious spectrophotometric method was used to determine the phospholipids in the crude egg lecithin. Also for the crude egg lecithin, it was necessary to use thin layer Chromatography (TLC) to determine the character of the phospholipids. The high-performance liquid chromatograghy was developed to determine exactly the content of phospholipids. The result showed that the method was rapid, accurate and repeatable, which is feasible to determine phospholipid.Second, the enzymatic extraction method was studied systematically. The order of the solvent added , centrifuge and filtration ,the content of ethanol was investigated and the optimal parameters were as follows: the solvent added before enzymes hydrolyzation , centrifuge and 95% ethanol is better than others. As for the separation solvent of phospholipid and triglyceride , ethyl acetate is better than acetone. The ratio of water to organic solvent was 1:8 for the better extracting rate . Different proteinases were used to pre–hydrolyze of egg yolk individually and by two proteinases used in sequence. The result showed that the best extracting rate of different proteinases was 63.5%.After compared with these ,the route of enzymatic hydrolysis was built. Then this thesis invistigated the factors of enzymatic hydrolysis ,the result was as follow: temperature of egg yolk enzymatic hydrolysis 50℃,time 2 hour ,the ratio of proteinase :substrate 3:1000,the best extraction ratio of phospholipid was 66.7%.Third , the column chromatography was applied in the further purification of phospholipid, which was a easy ,rapid way. After comparitation, Al2O3 column chromatography with ethanol as desorption was preferred. In addtion , the factor of column chromatography was also studied which indicated that the water content in Al2O3 phase was less than 8%,the volume of Al2O3 phase was better.