Chemists, Big People in a Big world.

Eggs!

...unscrambled.

Some Background History

There is culinary evidence that breads and cakes made with eggs were baked by the Ancient Egyptians and Romans.  It is thought that eggs were first used in baking as a binding or thickening agent.  Using eggs to leaven the bread was probably invented as a result. Food historians believe that soufflés (a French word which means “puffed up) were invented during the 18th century by the French.  It’s a light, egg-based dish just stiff enough to hold its shape.  It is in the soufflé in particular that the chemistry of eggs is most dramatic.

http://static.flickr.com/74/229229246_08e7ee85e8.jpg

Contained inside every egg is a clear liquid most commonly known as the egg white, the cytoplasm of the egg, however it's also called the albumen, (not to be confused with albumin, a kind of protein) the poggle, and the glaire.  It protects the egg yolk, as well as provides additional nutrition to help the embryo grow.  Many people don't realize it, but it would be impossible to discuss the egg white without going into chemistry.  In this page, I will explain some basic facts about the composition of egg whites, and then I'll go into the chemistry.

So, what do we do with egg whites, anyway?

The most common use for egg whites is  seperation for use in cooking, especially for tasty treats such as meringues, glairs, souffles, and kinds of omlettes.  As a matter of fact, that's where egg whites get their name--although they're clear at first, they turn white when beaten or cooked.  Egg whites are also used to remove sediments from champagne and beer, to clarify broths, was once used in the emulsion of traditional photographic paper, and used in schools to teach kids how to test for protein using Biuret reagent (I did that last year in Biology.)

Just one of the tasty treats that can be made using egg whites.  (http://www.lowcarbscenter .com/meringue.jpg)

What makes up an egg white? Eighty-three percent of an egg white is composed of water.  It also contains a lot of protein.  Olvalbumin is the largest protein constituent, being 54% of the egg white protein, followed by Conalbumin, (13%) Ovomucoid, (11%) and a small of amount of several other proteins.

ELEMENTAL COMPOSITION THE MAJOR ALBUMEN PROTEINS as measured by % of dry weight (Young 1963)

http://albumen.stanford.edu/library/c20/messier1991a.html

The proteins in egg whites, like all proteins, are made up of long chains of amino acids.  As they cook, they change from liquid to solid.  In their natural protein state, they’re shaped like coils that kind of look like fusilli pasta with links from one section of the coil to another.  The purpose of the links is to hold the coil tightly wound together.  Each natural protein (or coil) is separate, so you can see light between them.  This is why the egg white isn’t so white when you first break the egg—it’s clear.