Eggs and Egg Products

Abstract

The eggs of various birds are consumed throughout the world; however, the discussion that follows in this chapter is regarding hen eggs. Eggs are a natural biological structure with shells offering protection for developing chick embryos. They have numerous functions in food systems and must be protected against becoming or offering contamination. Eggs provide nutritive value and culinary variety to the diet, while being an economical source of food. Today, we see a reversal of dietary limitations, and healthy persons can enjoy eggs as long as they form part of a healthy, balanced diet.

Glossary

Air cell or air pocket

A space between shell membranes where air is found within the shell, typically at the large end of an egg.

Biological value

Eggs contain a score of 100 based on their efficiency in supporting the body’s needs; reflects the amount of nitrogen retained in the body, due to the completeness of the protein. (An incomplete protein is deaminated and nitrogen is not retained.)

Beading

Amber-colored syrup beads on top of baked meringue as a result of overcoagulation.

Binder

Holds the ingredients of a mixture or its breading together.

Candling

Viewing the inside and shell of an egg by holding it up to a bright light.

Clarify

To remove foreign particles from a hot liquid.

Coagulation

Extensive denaturation of protein molecules yielding a solid mass or gel.

Curdling

The protein precipitates, shrinks, releases water, and becomes tough.

Denaturation

Changes in the conformation of a protein caused by changes in temperature, an acidic pH, or by surface changes such as mechanical beating.

Digestible Indispensable Amino Acid Score (DIAAS)

A measure of protein quality. The preferred method of measuring protein quality recommended to replace the PDCAAS.

Egg substitute

Liquid or frozen egg white product with a “yolk” typically consisting of corn oil, NFMS, calcium caseinate, soy protein isolate, soybean oil, and other substances.

Emulsifier

Material that allows two ordinarily immiscible substances to mix.

Flocculated

Separation of overbeaten egg white foam into small masses.

Foam

Increased volume of beaten egg white that holds shape as protein coagulates around air cells.

Gel

A two-phase system where egg coagulates with liquid in a solid.

Pasteurization

Heating for a specific time at a temperature that eliminates pathogens.

Protein-digestibility-corrected amino acid score (PDCAAS)

A measure of protein quality that compares the amino acid balance with requirements of preschoolers and corrects for digestibility. Used by the FDA for labeling and by the WHO.

Digestible Indispensable Amino Acid Score (DIAAS)

It has been proposed as a replacement for PDCAAS. More data needs to be developed to support full implementation.

Salmonella enteritidis (SE)

Pathogenic, infection-causing bacteria especially prevalent in poultry and eggs.

Syneresis

“Weeping” or water leakage from coagulated egg.

Thickening agent

Increases viscosity.

Ultrapasteurization

High temperature, short time heat to kill pathogenic microorganisms.

Weeping

Syneresis or release of water from undercoagulated or underbeaten egg whites.