| Eggs yolk is rich in phospholipids, which have important physiological functions and nutritional values. The subject of this research was focused on the phospholipids and fatty acid distribution in varieties of eggs, including common chicken eggs:Hy-Line Brown shell eggs, Nick pink eggs, green shell eggs and brown shell eggs, as well as duck eggs, quail eggs and goose eggs. And a new method for determining total phospholipid content of the eggs was established, as well as an isocratic HPLC analysis method to determin the components of phospholipids is reseached. And the molecular species of six components of phospholipids were studied by the method of HPLC-ESI-MS. At last, the determination of changes in the duck egg phospholipid and fatty acid composition after different processing were studied. The main findings are as follows:The rapid analysis method applies to the determination of egg yolk phospholipid was establelished, take the mixed phospholipid standards (MPE:MPC=3:1) as a reference,3ml phospholipid test solution by ultrasonic assisted extraction add to2ml of the thiocyanate ferrous ammonium reagent followed with full shock mix, the reaction was tokeplace within30℃for20min, absorption was measured at470nm wavelength, the total phospholipid content of the egg yolk can be obtained by taking absorption into the mixed standard standard curve. the method detection is well speed, easy to operate, without digestion and less interference factors, is suitable for the rapid determination of total egg yolk phospholipids. The measured results of variety of eggs phospholipids showed that, Nick pink shell eggs had the highest content of phospholipids, reaching14.05%.A HPLC method was investigated to determin the six components of phospholipids within30minutes was established. The chromatographic condition is that taking a silica gel column of250mm×4.6mm with203nm were measured by UV. The mobile phase is acetonitrile/methanol/water (120:100:1.5, v/v/v) at a flow rate of0.8mL/min, with a injection of25uL. The egg yolk components of phospholipids were of well separation with stable baseline. The precision and linear relationship recoveries analysis results show that the method is fast, comprehensive and accurate in determination of egg yolk phospholipid content. The six varieties of egg phosphollipid conponent composition were analysised by this HPLC method, the results showed that PE and PC are the main phospholipid component in eggs with a content of more than90%of the total phospholipid. The PI component is the most obvious different among the different kinds of eggs.The fatty acid distribution in eggs total lipid fatty acids, phospholipids, triglycerides were researched:the main difference between phospholipids and fatty acid triglyceride is mainly about the compostion of C16:1, C20:4and C22:6. Triglycerides had five times higher C16:1(7.010.26%,1.720.02%, respectively) than the phospholipid. However, the phospholipid had much a higher C20:4n6(AA)(1.170.20%and5.610.04%, respectively), and C22:6is not detected in the triglyceride component. Egg yolk phospholipids MUFA, PUFA were higher than triglycerides and total lipids, especially DHA and AA, which were significantly higher than the total lipid of the egg yolk and egg yolks triglyceride.To some extent the egg yolk phospholipids is highly nutritious values and antioxidant function.The fatty acid distribution characteristics and differences of six phospholipids:PE, PI, LPE, PC, SM, and LPC made by HPTLC separation were analysised, the results showed that PE contained more PUFA (P<0.05), which had five times more C20:4, and2.5times more C22:6than PC, and PC had more SFA. PI had the highest content of C22:6, but in low amount of C20:4and n-6/n-3value, the AI and TI value was also low. SM contain high levels of C16:0and C18:1, LPC and LPE has the highest degree of SFA. The composition of fatty acids in different eggs varieties were also studied. The results showed that Hy-Line Brown shell eggs, contain the highest C16:0and the lowest content of C20:4in six eggs. Nick pink eggs showed the lowest ratio of n-6/n-3fatty acid. Arachidonic acid showed the highest mount in Green shell eggs, which had the lowest DHA content in four eggs. The brown shell eggs had the highest content of C18:3n3. The fatty acid differences between the Quail eggs and duck eggs were showed in the compositon of C16:0, C18:0, C22:6and C20:4, From the aspect of fatty acid composition, the phospholipid compostion were more similar in duck and quail eggs. The egg phospholipid molecular species were analysised by HPLC-ESI-MS, the yolk phospholipid fractions and the molecular species within each component were well researched by this method. By extrapolating the molecular ions peak and fragment ions peak of tandem mass, the molecular species composition of PI, PE, PC, SM, LPC and LPE were detected:PC showed16molecules species, the main molecular species were C16:0/C20:4and C16:0/C18:1; PI had12molecular species, the major molecular species were18:0/20:4and C16:0/C18:1; PE had11different molecular components, the main distribution of the species were C18:0/C20:4and C16:0/C18:1; SM had5kinds of molecular species, and the C16:0was the mainly molecules; LPE and LPC were found7and9molecules respectively, and the C16:0and C18:0are two main phospholipid molecular species of both component.The duck egg phospholipids and fatty acid composition were researched after different ways of processing, including heating, alkali processed into preserved eggs, salted processed into salted egg. Heating has almost no impact on duck egg phospholipid composition. After alkali process, the total phospholipid content decreased significantly than fresh eggs (11.44%to8.55%), PE and PC content decreased significantly accompanied with a significant increase of LPE and LPC content, and SM significantly increased. but the atherosclerotic index (AI) and thrombosis index (TI) of fatty acid was lower than the fresh eggs; After salted processed, the duck egg total phospholipid content was significantly increased (11.44%increase to13.80%); PC and PE content declined with the content of LPC and LPE increased significantly, but the magnitude of changes of salted eggs is less than preserved eggs, while SM had no apparent changes. The PUFA content of salted eggs decreased significantly, SFA and MUFA did not change significantly, and the AI the TI index showed unfavorable changes, which got the highest index value. |
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