Cholesterol in eggs from different species of poultry determined by capillary GLC

Abstract

This study compared two methods of egg cholesterol extraction and determination by gas liquid chromatography (GLC), validated by comparison with standard reference material (SRM 1845). The two extraction procedures were of comparable accuracy with dried whole egg samples of 0·25–0·5 g, but the direct saponification method was rapid, reduced occupational hazard, and quantitative precision was within 2% coefficient of variation. The validated procedure was used to determine cholesterol in eggs of several domestic avian species. Eggs produced by commercial types of chicken (White Leghorn) had the lowest cholesterol (11·5–11·8 mg/g yolk) compared to 13·0, 14·6, 15·2, 15·6, 16·5, 16·8 and 18·1 mg/g for Rhode Island Red chicken, guinea fowl, New Hampshire chicken, duck, pea fowl, domestic turkey and wild turkey eggs, respectively. Yolk cholesterol concentration of commercial White Leghorn chicken eggs was not influenced by age. However, eggs from older birds contained about 23% more cholesterol on a per egg basis (220 versus 179 mg) because of the larger yolk.