Yolk (vitelline)

The interior yellow globe that accounts for about 33 percent of the egg’s total liquid weight and includes all the fat and half the protein, as well as the higher proportion of minerals and vitamins (except niacin and riboflavin). The yolk provides phosphorus, manganese, iron, copper, iodine, calcium, and vitamins A, E, and D—it is one of the few foods with vitamin D. The yellow color varies, depending upon the type of feed given, but pale or deep, it is not indicative of nutritive value. The yolk is responsible for the emulsifying and enrichment properties of the egg. It 60 calories account for 90 percent of the total calories in an egg.