Parts of the Egg Exposed - Definitions We Must All Know!
Although the majority of us are familiar with such terminology
as egg whites, shells, and yolks, there are other egg related
terminologies that we may not be as knowledgeable about. In
this brief article, we will define some common and some not
so common egg related words so that we have a better understanding
of eggs and their biological components.
Air Cell: At the large end of the egg, it
is the empty space between the white and shell.
Blood Spots: They are usually found in an
egg yolk and do not mean the egg is fertilized. Instead blood
spots mean that some blood vessels on the yolk’s surface
suffered a rupture of a blood vessel while it was being developed.
To further evaluate these imperfections, one can utilize mass
candling or electronic spotters but these methods are not
always accurate.
Chalazae: Cord-like strands of egg white
that indicate egg’s freshness.
Germinal Disc: It looks like a slight depression
on the surface of the yolk but is actually the channel leading
to the center of the yolk. When an egg is fertilized this
disc allows sperm to enter and travel to the center allowing
the embryo to form.
Shell: It is the outer covering of an egg
that accounts for more than 10% of its total weight. It is
largely composed of calcium carbonate with small amounts of
calcium phosphate, organic matter (including protein) and
magnesium carbonate. Its color may range from white to brown
and inside of an egg’s shell are two membranes (inner
and outer).
Albumen: It is known as the egg white and
contains more than half of the egg’s total protein,
niacin, chlorine, riboflavin, magnesium, sodium, potassium
and sulfur.
Thin Albumen: The thin albumen is the second
layer from the shell (egg white) and spreads around the thick
white of the egg.
Thick Albumen: The thick albumen is the
third layer from the shell (egg white) and provides the major
source of riboflavin and protein. It stands higher and spreads
less than the thin albumen but is less prominent in lower
grade eggs.
Yolk: The yellow portion of the egg that
is based on the diet of the hen. It encompasses about 33%
of the egg’s liquid weight and contains the major source
of vitamins (A, D and E), minerals (phosphorus, manganese,
iron, iodine, copper, and calcium, zinc) and about half of
the protein. The yolk also contains all of the egg’s
fat.
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