Abstract: A new process was explored and established for the preparation of high purity egg yolk lecithin used for injection using fresh egg yolk as raw material,ethanol as the only extraction solvent.First of all,4 parts 96% (v/v) ethanol was used to precipitate the protein from the fresh egg yolk.The egg yolk protein as filter cake and the primary extract as filtrate were collected separately;after that,the remaining lecithin in filter cake was extracted by 4 parts 96% (v/v) ethanol for 3 times as the secondary extract.Then the primary and secondary extract were combined and stored at 9 ℃ over night to remove most of the egg yolk oil.Finally,the resulting supernatant was separated via silica gel column with 86% (v/v) ethanol as eluent,and the purity of egg yolk lecithin fraction,detected by HPLC,reached to 98%.Meanwhile,the extraction process was optimized as follows:for precipitation,35 ℃,the ratio of 96% (v/v) ethanol to fresh egg yolk was 4:1 (w/w),with 180 rpm stirring speed for 10 min;for extraction,60 ℃,the ratio of 96% (v/v) ethanol to filter cake was 4:1,standing 15 min for 3 times.Under optimized conditions,the extraction yield of egg yolk lecithin reached to 93.38%.

Key words: lecithin, egg yolk, extraction, purify