Studies On Preparation Of High-Purity Phosphatidylcholine From Egg Yolk Powder

Egg yolk has high contents of lecithin, accounting for about20%of yolk by dry weight,thus it is usually used as raw material for lecithin extraction. Phosphatidylcholine (PC) is themain effective component in egg yolk lecithin, which has a unique physicochemical propertyand physiological functions. PC is widely used in industries such as food，medicine，cosmeticsand so on. High purity PC has increased year by year in domestic demand, but our countrylags behind in the aspects of technology and research&development, thus high purity PCbasically relies on imports. Therefore, the aim of this paper is to build a safe and efficientproduction technology of high purity PC, providing theory supports for its industrialapplication. The main contents in this paper were concluded as follow:First of all, the qualitative and quantitative methods of PC and LPC in egg yolkphospholipids were determined. TLC can be used to obtain better separation of phospholipidscomponents in order to achieve the purpose of qualitative separation. Using HPLC methodcan be quantitative analysis of PC and LPC, and the detection conditions of this method weredetermined. The feasibility and stability of this method were verified through experiments.Further, solvent extraction order of egg yolk lecithin was determined. The results showedthe better order should be ethanol extraction first and then acetone deoiling. In ethanolextraction process, single-factor and orthogonal experiments were designed to study theeffects of factors on the purity and recovery of crude egg yolk lecithin. The optimizeextraction conditions were obtained as follows: extraction temperature was30℃; extractiontime was30min; ethanol concentration was85%; the liquid-solid ratio of ethanol and eggyolk powder was9(v/w); extraction times were2. Under these conditions, the purity oflecithin in the crude lecithin was71.40%, the recovery of lecithin was98.49%.Then, the process of ultrasonic assisted acetone deoil was applied to treat the crudelecithin in order to obtain egg powder lecithin. The ultrasonic extraction conditions wereinvestigated by purity and recovery of lecithin, the optimal conditions were as follows:ultrasonic time was20min; temperature was40℃; ultrasonic power was300W; liquid-solidratio of acetone and crude lecithin was9(v/w). Under this optimal condition, powder lecithincan be got with purity of93.10%and recovery of98.03%. HPLC was used to determine thecontent of PC and LPC. The results were that PC content of powder lecithin was73.09%andLPC content was4.95%.Egg yolk PC was purified by column chromatography for further treatment andhigh-purity PC product can be obtained. First of all, lecithin elution law was studied to chooseone for different stationary phases. And using the content of PC, LPC and the recovery of PCfrom products as a measure, the results were obtained as follows: the column size was D25×300mm; the mesh of aluminum oxide was100~200; the concentration of ethanol was95%;the flow rate was3.0mL/min; the loading amount was0.0625g/g aluminum oxide. Under theconditions, in product PC recovery was83.17%, PC content was92.25%and LPC contentwas2.92%. And some other indicators of egg yolk PC products were determined, which meetthe relevant standards.