不同饲养类型鸡蛋中脂类的含量测定

Determination of Egg Lipids with Different Feed Types

用甲醇和氯仿,使蛋黄溶液从一相系统转变成二相系统来提取脂类,通过三方向TLC来分离脂类中的组成成分;并将脂肪甲基化,用100m×0.25mm的GC毛细管柱来测定脂类中脂肪酸的组成。TLC结果表明,蛋黄脂类中由C、TG、CE、FFA、PE、PC、SM等组成,而且TG、CE和PC含量最高,其次为C和PE,含量最低的为FFA和SM。GC测定结果显示,蛋黄脂肪酸中16:0、18:0、9c18:1、18:2n6含量最高;与笼养鸡蛋相比,放养鸡蛋中18:1t、18:1c、饱和脂肪酸和单不饱和脂肪酸所占的比率都显著下降,分别为1.34%对0.69%,42.38%对39.06%,39.74%对37.90%,47.09%对43.30%。但多不饱和脂肪酸却有极显著增加,为12.09%对17.39%,这主要体现在18:2n6和ω3脂肪酸的显著增加,分别为9.91%对14.64%,0.23%对0.44%。ω3 Egg2组饱和脂肪酸比率(30.40%)比笼养鸡蛋和放养鸡蛋都极显著降低;多不饱和脂肪酸比率(25.56%)则极显著升高,且这种升高主要是18:3n3(7.55%)和ω3 (1.67%)脂肪酸的显著升高所致。表明不同的饲养类型,影响鸡蛋中某些脂肪酸的比例。

The lipids were extracted by using methanol and chloroform to make egg yolk solution from one phase into two phases;different components of yolk lipids were separated with three-dimensional thin layer chromatogram (TLC). Lipids weremethylated and determined by GC equipped with 100m×0.25mm capillary column. The results of TLC indicated that yolklipids contained cholesterol, triglyceride, cholesterol ester, free fatty acids, phosphatidylethanolamine, phosphatidylcholine andsphingomyelin. From the results of GC, the concentrations of fatty acids 16:0, 18:0, 9c18:1, 18:2n6 were highest. The rates oftrans and cis 18:1, and the rates of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in the eggs hatched byfree run hens were significantly decreased compared with those of caged hens (1.34% vs 0.69%, 42.38% vs 39.06%, 39.74% vs37.90% and 47.09% vs 43.30% respectively), but the rate of total of polyunsaturated fatty acids (PUFA) was very significantlyincreased (12.09% vs 17.39%). It was resulted from the increment of 18:2n6 and ω3 (9.91% vs 14.64% and 0.23% vs 0.44%).The concentration of SFA (30.40%) was very significantly decreased in ω3 Egg2 compared with that of eggs from caged and freerun hens, but the rate of total of polyunsaturated fatty acids (PUFA) was very significantly increased to 25.56%. It was causedby the increment of 18:3n3 and ω3 (7.55% and 1.67%). Different feed types for hens could affect the proportion of some fattyacids in eggs yolk.