| Egg yolk are rich in lipids, but the classification of the lipids have not been relatively clear, and there is no uniform standard. Most studies focus on measuring one or more active ingredients in the lipids, but not analysising the lipids systematically. This study analysised fatty acid composition of six varieties of egg yolks; the fatty acid composition of Highland brown shell egg yolks from different seasons; the fatty acid composition of Highland brown shell egg yolks from different areas; fatty acid composition of different varieties; and establish a fingerprint Map of egg yolk fatty acids by gas chromatography. The study result was following:The fatty acid composition of Highlan brown shell eggs, Nick eggs, Soil eggs, Nongda III eggs, Green shell eggs and Silkie eggs which are familiar in market were detected by gas chromatography. The result turned out that, The total lipids content of the six species eggs was between 32.7 g/100g-34.4 g/100g, and the average content of the eggs was 33.59g/100g. The phospholipid content of six species eggs was between 118 mg/g-189 mg/g, the average concentration of the phospholipid content of six species eggs was 149.5 mg/g. The cholesterol content of six species eggs was in the range of 8.2-12.4 mg/g, and the average concentration of the cholesterol content of six species eggs was 10.6mg/g. Fresh eggs mainly have 9 kinds of fatty acids, such as C14:0, C16:0,C16:1(n-7),C18:0,C18:1(n-9),C18:2(n-6),C18:3(n-3),C20:4(n-6),C22:6(n-3). The C18:1(n-9) was the highest, reached 42.6%. The contents of fatty acids were significantly different (P<0.05), except C16:0. The Jianghan Soil eggs had the most saturated fatty acid (P<0.05). The monounsaturated fatty acid and the Polyunsaturated fatty acid are the highest in Highland brown eggs (P<0.05). Nick eggs had the most omega-3 fatty acid, and the ratio of omega-3:omega-6 was the highest of them (P<0.05).The total lipids contents the phospholipid content and the cholesterol content of Highland brown shell egg yolks from springs summer,autumn and winter were detected. And the fatty acid composition of them were detected by gas chromatography. The result indicated that, the content of total lipid of Highland brown shell eggs in summer were 31.56 g/100g (P<0.05), lower than them in other three seasons. The cholesterol content of Highland brown shell eggs in spring and summer were 10.75mg/g and10.72mg/g, respectively (P<0.05). There was no significant difference in the content of phospholipid of Highland brown shell eggs in different seasons (P>0.05). The fatty acid composition of Highland brown shell egg yolks had been little effect. But the linolenic acid changes with the seasons change.The total lipids contents,the phospholipid content and the cholesterol content of Highland brown shell egg yolks from Zhengzhou, Wuhan and Nanjing were detected. And the fatty acid composition of them were detected by gas chromatography. The result turned out that, The content of total lipid of Highland brown shell eggs in Zhengzhou, Wuhan and Nanjing were 34.18 g/100g and 35.63 g/100g, respectively (P<0.05), higher than it in Nanjing. The content of phospholipid of Highland brown shell eggs in Wuhan and Nanjing were 153.87 mg/g and 160.04 mg/g (P<0.05), higher than it in Zhengzhou. The cholesterol content of Highland brown shell eggs in Zhengzhou was the lowest, as 8.47 mg/g(P<0.05). The content of Myristic acid, Oleic acid, linolenic acid and docosahexaenoic acid are different in different area(P<0.05). There was no significant difference in the content of palmitic acid, palmitic acid, stearic acid, linoleic acid and arachidonic acid in different area(P>0.05).The contents of total lipid, phospholipid, cholesterol of the Highland brown shell eggs, Nick eggs, Jianghan soil eggs, Agricultural University Three eggs, green shell eggs, Roman eggs these six different varieties of eggs are different, and fatty acid composition of these six different varieties of eggs are also are different. The results turned out, the content of total lipids in Highland brown eggs, Nick eggs were the highest,39.94 g/100g,37.96 g/100g, respectively. (P<0.05). The phospholipids in Roman eggs were the highest (P<0.05). No significant difference was found in the content of cholesterol between six varieties of egg yolks. Gene is one of the most important factors cause differences in fatty acid composition of egg yolks. Green shell eggs had the most omega-3 fatty acid, and the ratio of omega-3:omega-6 was the highest of them (P<0.05).GC fingerprinting was established in order to evaluate the quality of different varieties of eggs. The method of programmed temperature was used to separate the fatty acids. the data was analysisd by multivariate statistics. The result turned out, six varieties eggs are divided into three categories through the cluster analysis. Nick eggs, Jianghan soil eggs, Agricultural University Three eggs, silkie eggs are the same type, Highland brown shell eggs, and green shell eggs are one category alone. |
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