- Egg white
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Egg white is the common name for the clear liquid (also called the albumen or the glair/glaire) contained within an egg. It is the
cytoplasmof the egg, which until fertilizationis a single cell (including the yolk). It consists mainly of about 15% proteins dissolved in water. Its primary natural purpose is to protect the egg yolkand provide additional nutrition for the growth of the embryo, as it is rich in proteins and is of high nutritional value. Unlike the egg yolk, it contains a negligible amount of fat. Egg whites have many culinary and non-culinary uses for humans.
The egg white is approximately two-thirds of the total egg's weight out of its shell with 90% of that weight coming from water. The remaining weight of the egg white comes from
protein, trace minerals, fatty material, vitamins, and glucose. [McGee, 77] The U.S. large egg's white weighs 38 grams with 9.6 grams of protein, 0.3 grams of carbohydrateand 62 milligrams of sodium. The U.S. large egg white contains about 20 calories. [McGee, 79] Egg white contains approximately 40 different proteins. [Exploratorium] Below is a list of the proteins found in egg whites by percentage along with their natural functions.
Ovalbumin64% Nourishment; blocks digestive enzymes
Ovotransferrin12% Binds iron
Ovomucoid11% Blocks digestive enzymes
Globulins 8% Plugs defects in membranes, shell
Lysozyme3.5% Enzyme that digests bacterial cell walls
Ovomucin1.5% Thickens egg white; inhibits viruses
Avidin.06% Binds vitamin (biotin)
* Others 10% Bind vitamins, block digestive enzymes... [McGee, 77]
Egg white is without dietary cholesterol, which is a target component for reduction in the American diet.cite web
title=Cook for lower cholesterol | publisher=
American Heart Association
*It is often separated and used for cooking (for glairs,
meringues, soufflés, and some omelets), hence it derives its name: when egg white is beaten or cooked it turns white.
*In recipes calling for egg yolk, two egg whites can often be used to replace one egg yolk.
*In schools it is often used to teach pupils how to test for protein using
*It is used to remove sediments from champagne and
beerand to clarify broths.
*It was used in the emulsion of traditional photographic paper.
*It was used in medieval medicine to treat wounds and broken bones. [Gilbertus, 6]
*They are recommended for consumption by
chemotherapyand renalpatients as a source of 90g of lean protein. [http://www.eggology.com/Public/FAQ/index.cfm Fresh Egg Whites, Kosher Egg whites, Pure Protein Food - Eggology, Inc ] ] cite web|publisher= National Kidney Foundation|title=Transplant Chronicles|date=Summer/Fall 2007|pages=11|url=http://www.kidney.org/transplantation/transaction/pdf/tc_sufa07.pdf|format=pdf]
*It is used by athletes and
bodybuildersas a health food supplement. [ EggologyOfficial Website [http://www.eggology.com/Public/Products/Athletes/index.cfm] ]
*It can be used as a base for waterproof glues. [Glue of the Month, 2002 March [http://www.thistothat.com/gom/2002.03.shtml] ]
eggingvandalism the egg white can degrade house and car paint. After drying it is extremely hard to remove.
Biotin deficiencycan be caused by excessive consumption of raw egg whites over a long period (months to years). Egg whites contain high levels of avidin, a protein that binds the vitamin biotinstrongly.
All proteins, including those in egg white, are made of long chains of
amino acids which are similar to beads on a string. In a raw egg, these chains are raveled up in a specifically arranged compact mass. Chemical bonds and interactions between the amino acids within each protein hold this mass in a specific shape and stop it from unraveling. As an egg cooks, the heat causes the bonds within the proteins to break, a process called denaturation. [ Elmhurst College] As these proteins chains unfold and entangle with other proteins, new bonds form between these amino acids and the amino acids of neighboring proteins, causing the texture to change.
Egg white foam
Creating an egg foam
The physical stress of beating the egg white can create a foam. There are two types of physical stress caused by the beating of the egg whites with a whisk, the first being that the whisk drags the liquid through itself creating a force that unfolds the protein molecules. This process is called denaturation. "The second stress" comes from the mixing of air into the whites which causes the proteins to come out of their natural state. These denatured proteins gather together where the air and water meet and create multiple bonds with the other unraveled proteins and thus becomes a foam holding the incorporated air into place. [McGee, 102]
tabilizing egg white foam for culinary purposes
Copperbowls have been used in Francesince the 18th century to stabilize egg foams. The copper in the bowl assists in creating a tighter bond in reactive sulfuritems such as egg whites. The bond created is so tight that the sulfurs are prevented from reacting with any other material. A silver plated bowl will have the same result as the copper bowl or a pinch of powdered copper supplement from a health store used in a glass bowl will yield the same result as well. Drawbacks of the copper bowl include the expense of the bowl itself, as well as the fact that the bowls are difficult to keep clean. Copper contamination from the bowl is minimal as a cup of foam will contain a tenth of one's daily normal intake level. [McGee, 102-103]
Adding an acid
Cream of tartar(potassium bitartrate) is an acidic salt that can be used to change the pHof the egg white to an acidic range by boosting the number of free-floating hydrogen ions in the egg white. This has the effect of stabilizing the foam, and is therefore an alternative to using a copper bowl. 1/8 teaspoon/0.5g cream of tartar should be used per one egg white to create this effect. 1/2 teaspoon/2ml of lemon juice can also be used to create the same results. [McGee, 103]
Elmhurst College, [http://www.elmhurst.edu/~chm/vchembook/568denaturation.html Denaturation Protein]
Exploratorium, [http://www.exploratorium.edu/cooking/eggs/eggcomposition.html Anatomy of an Egg]
*Gilbertus. "Compendium Medicine Gilberti Anglici Tam Morborum Universalium Quam Particularium Nondum Medicis Sed & Cyrurgicis Utilissimum". Lugduni: Impressum per Jacobum Sacconum, expensis Vincentii de Portonariis, 1510.
*Good Eats, [http://www.goodeatsfanpage.com/Season4/Cake/CakeTranscript.htm Let Them Eat Foam] . DVD. Television Food Network, June, 13 2001.
*McGee, Harold. "On Food and Cooking: The Science and Lore of the Kitchen". New York: Scribner, 2004.
* [http://www.alternativephotography.com/process_albumen_paper.html How to make albumen photographic paper]
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Look at other dictionaries:
egg white — noun count or uncount the clear part of an egg that becomes white when you cook it … Usage of the words and phrases in modern English
egg white — ► NOUN ▪ the clear, viscous substance round the yolk of an egg that turns white when cooked or beaten … English terms dictionary
egg white — noun the white part of an egg; the nutritive and protective gelatinous substance surrounding the yolk consisting mainly of albumin dissolved in water she separated the whites from the yolks of several eggs • Syn: ↑white, ↑albumen, ↑ovalbumin •… … Useful english dictionary
egg white — UK / US noun [countable/uncountable] Word forms egg white : singular egg white plural egg whites the clear part of an egg that becomes white when you cook it … English dictionary
egg white — white liquid part of an egg (as opposed to the yellow yolk) … English contemporary dictionary
egg white — the white of an egg, esp. a hen s egg, used in cooking; albumen. [1895 1900] * * * … Universalium
egg white — Synonyms and related words: albumen, batter, bonnyclabber, butter, caviar, clabber, cornstarch, cream, curd, dough, egg, eggshell, fish eggs, gaum, gel, gelatin, glair, glop, glue, gluten, goo, gook, goop, gruel, gumbo, gunk, jam, jell, jelly,… … Moby Thesaurus
egg white — noun the clear, viscous substance round the yolk of an egg that turns white when cooked or beaten … English new terms dictionary
ˈegg ˌwhite — noun [C/U] the clear part of an egg that becomes white when you cook it … Dictionary for writing and speaking English
egg-white — adjective a) Having the color of egg whites. b) Made of egg whites … Wiktionary