• Types, structure, average nutritional composition, nutritional value and dietetic value of eggs
• Guidelines for buying and storing eggs
• Labelling regulations for egg boxes and eggs
Types of eggs
Eggs are a nutritious, versatile and widely available food. They are easily digestible and suitable for all age groups. There are many different types of eggs.
• Free-range eggs: from birds that are able to roam free in large barns and are permitted outdoors for at least part of the day.
• Barn eggs: from birds that are able to roam free in large barns.
• Cage eggs: from birds kept in enriched cages with slanted floors that allow eggs to roll out onto a conveyor belt.
• Organic eggs: from birds that are fed special organic feed that is not treated with chemical pesticides or fertilisers. The birds are also not treated with growth hormones or given antibiotics.
• Omega-3 eggs: from birds that are fed a diet high in omega-3. Omega-3 sources may include linseed or seaweed.
Structure of eggs
Eggs are composed of three main parts: shell, white and yolk.
• Shell (10%): a hard protective layer composed mainly of calcium carbonate. Shells are inedible and porous. They vary in colour, depending on the breed of bird that laid the egg. The colour does not affect the egg’s nutritional value or quality. On the inside of the shell is a thin membrane that encloses the white and yolk and leaves an air space at the wider end of the egg.
110 Complete Home Economics Shell Yolk Membrane Omega-3 eggs Hens in enriched cages
• Testing the freshness of eggs • Guidelines for preparing eggs • Culinary uses of eggs • Effects of cooking on eggs • Properties of eggs • Egg Quality Assurance Scheme (EQAS)
