BASIC FOODS

• Yolk:

  • The yellow or orange portion found in the center of the egg; constitutes about 30%/33% of the egg’s weight
  • Is dense in nutrients
  • Yellow in color because of meta carotene
  • High in Vitamin A and Iron
  • Germinal disc appears darker if the egg has been fertilized, but has no effect on the taste, functional properties, or nutritional value of the egg
  • Fertilized eggs do not develop once refrigerated
  • The color of the yolk depends on the hen’s diet
• Latebra:

  • Tube connecting the white yolk to the germinal disk in the yolk
• Vitelline membrane:

  • Sac enclosing the yolk
• Chalizeferious layer:

  • Membranous layer surrounding the vitelline membrane of the yolk
• Germinal disk:

  • Blastoderm of yolk located at the edge of the yolk and connected to the white yolk
• Components found in the yolk:

  • Lipovitellins
  • Phosvitin
  • Low density lipoprotein (ldl)
• White (albumin):

  • Accounts for 58%/67% of the egg’s weight
  • Made up of water and protein as well as layers differing in viscosity determined by the type and amount of protein in the egg white
• Chalazae:

  • Thick rope-like extensions at the top and bottom of the egg that anchor the yolk in the thick white surrounding
  • Secures the yolk to its vitelline membrane, so it stays in the middle of the egg
• Thin albumen:

  • The rather fluid egg white adjacent to the yolk and to the inner membrane
• Thick albumen:

  • The thick protein around the yolk
• Lysozyme:

  • A germicidal agent which dissolves the cell membrane of bacteria
• Conalbumin:

  • A protein which binds with iron making it unavailable for bacterial growth
• Shell membranes:

  • Found between the egg white and the shell are two membranes, an inner and outer shell membrane
  • Important defenses against bacterial invasion
  • Made of keratin mucia
• Air cell:

  • Located between the two shell membranes at the larger end of the egg
  • Formed as the freshly laid eggs cool
  • When its contents contracts, the inner shell membrane separates from the outer shell membrane to form the air cell
• Shell:

  • Made up of calcium carbonate
  • Brittle, rigid, and impervious
  • Has tiny pores allowing gases to pass in and out of the egg for the developing embryo
  • Serves as a protective covering that aids in maintaining freshness
• Bloom or cuticle:

  • A natural protective cover sealing the shell pores when the egg is laid
  • Sold eggs are washed, removing this protective cuticle
  • Producers apply a thin coat of edible oil onto the shell