Comprehensive evaluation of fatty acids in foods. III. Eggs and egg products.

To prepare a comprehensive table of lipids and fatty acids in foods, the U.S. Department of Agriculture has has conducted an intensive survey of the world's literature published since 1960. Examination of an extensive number of reports on the fatty acid composition of the lipids of eggs of the domestic hen shows the composition to be relatively stable and subject to alteration only by major changes in dietary fat. Large eggs contain more lipid and fatty acids on a per-egg basis than do small eggs. Complete extraction of bound lipid in egg yolk is necessary for quantification of lipid classes and cannot be achieved with apolar solvents. Lipid class compositional studies indicate that 83 percent of total egg lipids are fatty acids. This percentage figure provides the basis for converting fatty acid data expressed as weight per cent methyl esters to the gram-per-100-gm,-food basis used in nutrient tables. Reliable, up-to-date tabulations of total lipids and fatty acids in eggs of different species and egg products are presented.