This document discusses the composition and nutritional value of eggs. It describes how eggs are laid by many species including birds, reptiles, amphibians, and fish. The most commonly consumed egg is the chicken egg, which provides vitamins, minerals, and amino acids. It explains how applying heat or beating egg whites causes the proteins to unfold and bond together. Egg yolks contain emulsifiers that allow oil and water to blend. Various uses of eggs in cooking are outlined, such as binding ingredients, coating foods, glazing pastries, emulsifying mixtures like mayonnaise, and clarifying broths.

1. A NOT SO BRIEF LOOK AT
Abigail Barrett
&
Annique McLune

2. What is an egg?
 An egg is an oval or round object laid by a
female bird, reptile, fish, or invertebrate, usually
containing a developing embryo. The eggs of
birds are enclosed in a chalky shell, while those
of reptiles are in a leathery membrane.

3. Eggs Cont.
Eggs are laid by female animals of many different
species, including birds, reptiles, amphibians, and
fish, and have been eaten by humans for
thousands of years.
Bird and reptile egg consist of a protective
eggshell, albumen (egg white), and vitellus (egg
yolk), contained within various thin membranes.
Popular choices for egg consumption are chicken,
duck, quail, roe, and caviar, but the egg most often
consumed by humans is the chicken egg, by a
wide margin.

4. Composition of an Egg

5. Nutritive Value of Eggs
 Chicken eggs are the most commonly eaten
eggs. They supply all essential amino acids for
humans and provide several vitamins and
minerals, including retinol (vitamin A), riboflavin
(vitamin B2), folic acid (vitamin B9), vitamin B6,
vitamin B12, choline, iron, calcium, phosphorus
and potassium. Although not as abundant as red
meats, eggs are a source of CoQ10 depending
on how they are prepared.
 All of the egg's vitamins A, D, and E are in the
egg yolk. The egg is one of the few foods to
naturally contain vitamin D.

6. Science of Eggs
 When you apply heat, you agitate those placidly
drifting egg-white proteins, bouncing them
around. They slam into the surrounding water
molecules; they bash into each other. All this
bashing about breaks the weak bonds that kept
the protein curled up.
 The egg proteins uncurl and bump into other
proteins that have also uncurled. New chemical
bonds form—but rather than binding the protein
to itself, these bonds connect one protein to
another.
HEAT ‘EM

7. Science of Eggs Cont.
After enough of this bashing and bonding,
the solitary egg proteins are solitary no
longer. They’ve formed a network of
interconnected proteins. The water in which
the proteins once floated is captured and
held in the protein web. If you leave the eggs
at a high temperature too long, too many
bonds form and the egg white becomes
rubbery.

8. Science of Eggs
 When you beat raw egg whites to make a soufflé
or a meringue, you incorporate air bubbles into
the water-protein solution. Adding air bubbles to
egg whites unfolds those egg proteins just as
certainly as heating them.
 Egg-white proteins contain both hydrophilic and
hydrophobic amino acids. When the protein is
curled up, the hydrophobic amino acids are
packed in the center away from the water and
the hydrophilic ones are on the outside closer to
the water.
BEAT ‘EM

9. Science of Eggs Egg yolk contains a number of emulsifiers, which is
why egg yolks are so important in making foods such
as hollandaise and mayonnaise.
 Many proteins in egg yolk can act as emulsifiers
because they have some amino acids that repel
water and some amino acids that attract water. Mix
egg proteins thoroughly with oil and water, and one
part of the protein will stick to the water and another
part will stick to the oil.
 Lecithin is another important emulsifier found in egg
yolk. Known as a phospholipid, it’s a fatlike molecule
with a water-loving “head” and a long, water-fearing
“tail.” The tail gets buried in the fat droplets, and its
head sticks out of the droplet surface into the
surrounding water. This establishes a barrier that
prevents the surface of the fat droplet from coming
into contact with the surface of another fat droplet.
MIX ‘EM

10. Uses of Eggs in Cookery
 1. BINDING
The stickiness of the egg helps to attach crumbs or
items to food and binds the ingredients together.
Examples: you can add an egg yolk to burgers or
fish cakes, it will help them to stick together.
An egg batter provides a binder for added coating,
frequently an outer coating of flour, bread, crumbs
or batter is added to food such as meatloaf to
enhance its appearance, texture or flavor.

11. Uses of Eggs in Cookery Cont.
 2. COATING
Beaten eggs can be used to coat fish or chicken
portion before they are dipped into breadcrumbs
and fried. This gives a crisp and attractive finish.

12. Uses of Eggs in Cookery Cont.
 3. GLAZING
If pastry and scones are brushed with beaten egg
and milk, they will have a shinny golden brown
appearance when cooked.

13. Uses of Eggs in Cookery
 4. EMULSIFYING AGENTS
Eggs are used to form stable emulsion when you add an
egg or egg yolk to mayonnaise, it helps the oil and vinegar
to stay smoothly blend together. Eggs are also used as
emulsifiers in ice creams, cakes and cream puffs.

14. Uses of Eggs in Cookery Cont.
 5. CLARIFYING
Raw eggs maybe added to hot broths. Egg whites
will hold impurities and bring them to the top of a
simmering liquid.

15. Open Discussion

16. Egg Manipulation

17. Egg Manipulation

18. The Egg.  Jk. The End.