Egg Science: Composition, Quality, and Products

Egg Proteins

Dispersion containing particles uniformly distributed in a protein solution or plasma, identified as areas of yolk granules, low-density lipoprotein figures, and myelin.

Proteins and Lipoproteins of Particles

Fosvitin: A highly phosphorylated phosphoprotein rich in serine, serving as a phosphorus reserve for the embryo.

Plasma Proteins and Lipoproteins

• Livetin: Forms the globular fraction. Its components are related to plasma proteins.
• Low-density lipoproteins.
• Ovovitellin: A fraction rich in phosphorus and sulfur. The action of the enzyme chymosin on the clot causes dephosphorylation, producing heat and phosphorus-rich peptides.

Fresh Eggs

Fresh eggs are those with natural color and flavor, having undergone no manipulation beyond dry cleaning.

Defective Eggs

Defective eggs include those that are broken, even partially, but whose membranes are intact; those without off-odor or flavor; those that show a dark shadow when candled (e.g., using an Eggtester); and those with an air cell height greater than 12mm.

Eggs Unfit for Consumption

Eggs unfit for human consumption come from gallinaceous or webbed fowl. They are unsuitable due to off-flavor or smell, contamination by bacteria or fungi, rot, a clear greenish appearance, being incubated (sanguine), having a movable air cell height greater than 20mm, or being preserved by unauthorized procedures.

Egg Derivatives

These are products made wholly or partly from chicken eggs, devoid of shell, and intended as feedstock for food manufacturing.

• Derived Units: Formed by the whole egg (shelled) or the white and yolk separately.
• Dry Derivative: Obtained by dehydration or desiccation of a primary derivative.
• Composite Products: Obtained from a dry derivative mixed with other substances, containing at least 50% egg.
• Frozen Eggs: Primary derivatives made from fresh, chilled, or defective eggs that are shelled and homogenized. These are frozen in a liquid state at temperatures around -40°C.
• Egg Powder: Derived from dried egg after water evaporation.
• Dried Egg Yolk: Derived from dried yolk after removing water.
• Dried Egg White: A dry derivative obtained by removing water from the egg white.

External Egg Inspection

Inspection begins by checking the integrity of the shell, its cleanliness, and color.

In the shell, you can find:

• Rough surfaces without deformation: Indicate eggs preserved with lime.
• Rough surfaces deformed under pressure: Indicate eggs from birds that have suffered from infectious bronchitis.
• Exudation: Indicates eggs from cold storage.
• Moldy surfaces: Indicate poor storage in wet conditions.
• Unusual odor: Indicates storage with substances that emit a strong odor.