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SHELL
- the first line of defence against the entry of bacteria
- can be brown or white; nutritional value of the egg is the same
- composed mainly of calcium carbonate
- approximately 8,000 to 10,000 tiny pores allow moisture and gases in (O2) and out (CO2)
SHELL MEMBRANES
- there are two membranes on the inside of the shell
- one membrane sticks to the shell and one surrounds the white (albumen)
- the second line of defence against bacteria
- composed of thin layers of protein fibres
GERMINAL DISC
- appears as a slight depression on the surface of the yolk
- the entry for the fertilization of the egg
WHITE (ALBUMEN)
- there are two layers: thin and thick albumen
- mostly made of water, high quality protein and some minerals
- represents 2/3 of the egg's weight (without shell)
- when a fresh egg is broken, the thick albumen stands up firmly around the yolk
CHALAZA
- a pair of spiral bands that anchor the yolk in the centre of the thick albumen
- the fresher the egg the more prominent the chalazas
- unnoticeable when the egg is cooked
YOLK MEMBRANE
(VITELLINE MEMBRANE)
- surrounds and holds the yolk
- the fresher the egg the stronger the membrane
YOLK
- the egg's major source of vitamins and minerals, including protein and essential fatty acids
- represents 1/3 of the egg's weight (without shell)
- yolk colour ranges from light yellow to deep orange, depending on the hen's food
AIR CELL
- forms at the wide end of the egg as it cools after being laid
- the fresher the egg the smaller the air cell
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