Culture Tube Method for the Determination of Total Cholesterol in Egg Yolk Lipid

Culture Tube 방법에 의한 난황중의 Cholesterol 정량

  • Ha, Yeong-Lae (Dept .of Agricultural Chemistry , Gyeongsang National University) ;
  • Kim, Jeong-Ok (Dept.of Cheistry , Pusan Women's University)
  • Published : 1994.12.01


A simple, reproducible , and accurate enzymatic method using a cholesterol assay kit was developed to quantify total cholesterol content in egg yolk. Total egg yolk lipid was extracted with hexane : isopropanol(3 : 2, v/v) mixture. Samples containing various amount of the total lipid(0-3mg) in optically identifical culture tubes were reacted for 10 min in a water bath (37$^{\circ}C$) with the enzyme solution (5ml) from the cholesterol assay kit. Cholesterol content of the reaction mixturesin culture tubes was spectrophotometrically determined by two different ways : (1) using the culture tube as a curvette(designate culture tube method ; CTM) and (2) the quartz cvette containing the reaction mixture transferred from the culture tube (designate standard cvette method, SCM). CTM revealed lower cholesterol content in 0.1-1.0mg lipid sample range that SCM did, but not significant. For more than 2.0mg lipid sample, CTM gave significantly (p<0.01) lower cholesterol content relative to that by SCM, suggesting that SCM give a false positive result from the sample containing more than 2 mg lipid due to the interference of absorbance by lipid dispersed in the reaction solution . Cholesterol content of less than 1.0mg lipid sample by CTM was proportional to the amount of lipid used, but its linear relationship was not seen in more than 2mg lipid sample. Thus, to determine the appropriate lipid amounts (mg) analyzed . A constant level (41$\mu\textrm{g}$/mg) of cholesterol concentration was observed from the sample containing 0.1-1mg lipid. after which the cholesterol level was dropped to less than 41$\mu\textrm{g}$ /mg. Cholesterol concentration in egg yolk samples quantified by CTM was in accordance with that by GC method. These results suggest that CTM is an useful method for the quantification of cholesterol in egg yolk lipid and other lipids as well.


  1. Atherosclerosis v.18 Studies on cholesterol metabolism in rats by application of D₂O and mass spectrometry Peng,S.K.;Ho,K.J.;Milkkesom,B.;Taylor,C.B.
  2. Am. J. Epidemiol. v.112 Total serum cholesterol and cancer mortality in a middle aged male population Cambien,F.;Ducimette,P.;Richard,J.
  3. Human nutrition : Cancer and nutrition Serum cholesterol and cancer McMicheal,A.I.
  4. J. Agric. Food Chem. v.37 Overestimation of the sholesterol content of eggs Beyer,R.S.;Jenser,L.S.
  5. Poultry Sci. v.68 Cholesterol content of commercially produced eggs in Georgia Beyer,R.S.;JensenmL.S.
  6. Canadian J. Animal Sci. v.71 Survey of cholesterol level of commercial eggs produced on Canadian farms Chung,S.L.;Ferrier,L.K.;Squires,E.J.
  7. Poultry Sci. v.70 Comparison of four different methods for egg cholesterol determination Jiang,Z.;Fenton,M.;Sim,J.S.
  8. Poultry Sci. v.70 Egg cholesterol values in relation to the age of laying hens and to egg yolk weights Jiang,Z.;Sim,J.S.
  9. J. Chrom. v.540 Determination of egg yolk cholesterol content by on column capillary gas chromatography Fenton,M.;Sim,J.S.
  10. J. Liquid Chrom. v.14 HPLC determination of cholesterol esters in the digestive gland gonad complex of Biomphalaria glabrata snails fed hen's egg yolk versus leaf lettuce Shetty,P.H.;Park,Y.Y.;Fried,B.;Sherma,J.
  11. Poultry Sci. v.69 Plasma cholesterol responses to ACTH in Japanese quail following 18 generations of selection Marks,H.L.;Siegel,H.S.;Latomer,J.W.
  12. J. Agric. Food Chem. v.34 High-preformance liquid chromatographic method for the quantification of cholesterol epoxides in spray dried egg Sugino,K.;Terao,J.Murakami,H.;Matsushita,S.
  13. Poultry Sci. v.69 Effect of feeding cholesterol to laying hens an chicks on cholesterol metabolism in pre-and posthach chicks Jiang,Z.;Cherian,G.;Robinson,F.E.;Sim,J.S.