The yolk of an egg has excellent binding
properties because it contains lecithin, a natural emulsifier. Egg yolks
are essential for emulsifying or binding together classic sauces such as
hollandaise and mayonnaise. Egg yolks are also used for their thickening
properties. They are often added to custards, puddings, and other mixtures
for a richer texture. One egg yolk contains 5 grams of fat (mostly
unsaturated), 213 mg of cholesterol, and a range of beneficial B vitamins.
Storing egg yolk is simple. Just cover the
egg yolk with a small amount of water, seal in an airtight container, and
refrigerate for up to 3 days. You can also freeze egg yolks, but they
become very thick. If you must freeze them, beat in a speck of salt or a
scant 1/2 teaspoon sugar or corn syrup per egg yolk to keep them smooth
and usable. Choose salt or sugar depending on how the egg yolk will be
used. Thaw overnight in the refrigerator. use 1 teaspoon thawed egg yolk
for each fresh yolk called for in the recipe.