Egg white

Egg White

	Email		Print
	Bookmark		Link

Egg white

Egg white is the common name for the clear liquid (also called the albumen or the glair/glaire) contained within an egg

Egg (biology)

In most birds and reptiles, an egg is the zygote, resulting from fertilization of the ovum. To enable incubation the egg is usually kept within a favourable temperature range as it nourishes and protects the growing embryo....
. It is the cytoplasm

Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
of the egg, which until fertilization is a single cell

Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
(including the yolk). It consists mainly of about 15% protein

Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
s dissolved in water. Its primary natural purpose is to protect the egg yolk

Egg yolk

An egg yolk is the part of an Egg which serves as the food source for the developing embryo inside. Prior to fertilization the yolk together with the germinal disc is a single Cell ....
and provide additional nutrition for the growth of the embryo

Embryo

An embryo is a multicellular organism ploidy eukaryote in its earliest stage of development, from the time of first cell division until birth, Egg , or germination....
, as it is rich in proteins and is of high nutritional value.

Discussion

Ask a question about 'Egg white'

Start a new discussion about 'Egg white'

Answer questions from other users

Full Discussion Forum

Composition

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

Protein

Mineral

A mineral is a naturally occurring solid formed through Geology processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties....
s, fatty material, vitamin

Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be biosynthesis in sufficient quantities by an organism, and must be obtained from the diet....
s, and glucose

Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
. The U.S. large egg's white weighs 38 grams with 4.7 grams of protein, 0.3 grams of carbohydrate

Carbohydrate

Carbohydrates or saccharides are the most abundant of the four major classes of biomolecules. They fill numerous roles in living things, such as the storage and transport of energy and structural components ....
and 62 milligrams of sodium

Sodium

Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
. The U.S. large egg white contains about 20 calorie

Calorie

The calorie is a pre-SI metric system unit of energy. The unit was first defined by Professor Nicolas Cl?ment in 1824 as a unit of heat. This definition entered French and English dictionaries between 1841 and 1867....
s. Egg white contains approximately 40 different proteins. Below is a list of the proteins found in egg whites by percentage along with their natural functions.

Ovalbumin
Ovalbumin

Ovalbumin is the main protein found in egg white, making up 60-65% of the total protein. While Ovalbumin displays sequence and three-dimensional homology to the serpin superfamily, it is a noninhibitory serpin ....
64% Nourishment; blocks digestive enzymes
Ovotransferrin
Ovotransferrin

Ovotransferrin is a glycoprotein of egg white albumen. Transferrins are iron binding proteins and acute phase reactants of animal serum. The sequence of ovotransferrin is similar to that observed for serum transferrin in many species....
12% Binds iron
Ovomucoid 11% Blocks digestive enzymes

Egg white has no dietary cholesterol

Cholesterol

Cholesterol is a lipidic, waxy alcohol found in the cell membranes and transported in the blood plasma of all animals. It is an essential component of mammalian cell membranes where it is required to establish proper membrane permeability and membrane fluidity....
, which is a target component for reduction in the American diet.

Uses

It is often separated
Separating eggs

Separating eggs is a process usually used in cooking, in which one removes the egg yolk from the egg white. This is used to allow one part of the egg to be used without the other part — for instance, many recipes require frothing egg whites to make a foam, which will not work if the yolk is also included, as fat prevents eggs from foam...
and used for cooking (for glairs, meringue
Meringue

Meringue is a type of dessert made from whipping egg whites and Powdered sugar . Some meringue recipes call for adding a binding agent such as cream of tartar or the cornstarch found in confectioner's sugar....
s, soufflé
Soufflé

A souffl? is a light, fluffy, baking dish made with egg yolks and beaten egg whites combined with various other ingredients and served as a savory main dish or sweetened as a dessert....
s, and some omelette
Omelette

An omelette or omelet is a preparation of beaten Egg cooked with butter or Cooking oil in a frying pan, usually folded around a filling such as cheese, vegetables, meat , or some combination of the above....
s), 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.
It is sometimes used as a low-fat substitute for whole egg to stick breadcrumb
Breadcrumb

Breadcrumbs or bread crumbs are small particles of dry bread, which are used for breading or crumbing foods, topping casseroles, stuffing poultry, thickening stews, and adding inexpensive bulk to meatloaf and similar foods....
s to meat or vegetables.
In schools it is often used to teach pupils how to test for protein using Biuret reagent
Biuret reagent

The Biuret reagent is made of potassium hydroxide and copper sulfate , together with potassium sodium tartrate . The blue reagent turns violet in the presence of proteins, and changes to pink when combined with short-chain polypeptides....
.
It is used to remove sediments from champagne and beer
Beer

Beer is the world's oldest and most widely consumed alcoholic beverage and the third most popular drink overall after water and tea. It is produced by the brewing and Fermentation of starches, mainly derived from cereal?the most common of which is malted barley, although wheat, maize , and rice are widely used....
and to clarify broth
Broth

Broth is a liquid in which bones, meat, fish, cereal grains, or vegetables have been simmering. Broth is used as a basis for other edible liquids such as soup, gravy, or sauce....
s.
It was used in the emulsion of traditional photographic paper
Albumen print

The albumen print, also called albumen silver print, was invented in 1850 by Louis D?sir? Blanquart-Evrard, and was the first commercially exploitable method of producing a photographic print on a paper base from a Negative ....
.
It was used in medieval medicine to treat wounds and broken bones.
They are recommended for consumption by chemotherapy
Chemotherapy

Chemotherapy, in its most general sense, refers to treatment of disease by chemicals that kill cells, specifically those of micro-organisms or cancer....
and renal patients as a source of 90g of lean protein.
It is used by athletes and bodybuilders as a health food supplement, to aid in the building of muscle.
It can be used as a base for waterproof glues.
During egging
Egging

Egging refers to the act of throwing Egg at houses, cars, or people. Egging is a form of misdemeanor in most areas.Eggs are capable of causing damage when thrown at property and egging is usually considered vandalism for this reason....
vandalism the egg white can degrade house and car paint. After drying, it is extremely hard to remove.

Nutrition

Biotin deficiency

Biotin deficiency is a rare nutritional disorder which can become serious, even fatal, if allowed to progress untreated. It can occur in people of any age, ancestry, or gender....
can be caused by excessive consumption of raw egg whites over a long period (months to years). Egg whites contain high levels of avidin

Avidin

Avidin is a tetrameric protein produced in the oviducts of birds, reptiles and amphibians which is deposited in the whites of their eggs. In chicken egg white, avidin makes up approximately 0.05% of total protein ....
, a protein that binds the vitamin

Vitamin

Biotin

Biotin, also known as vitamin H or B7, has the chemical formula C10H16N2O3S , is a water-soluble B-complex vitamin which is composed of an ureido ring fused with a tetrahydrothiophene ring....
strongly.

Denaturation

All proteins, including those in egg white, are made of long chains of amino acid

Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
s 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

Denaturation (biochemistry)

Denaturation is a process in which proteins or nucleic acids lose their structure by application of some external stress or compound for example, treatment of proteins with strong acids or bases, high concentrations of inorganic salts, organic compound solvents , or heat....
. 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. At 62-65°C, the most heat sensitive protein in egg white, ovotransferrin

Ovotransferrin

Ovotransferrin is a glycoprotein of egg white albumen. Transferrins are iron binding proteins and acute phase reactants of animal serum. The sequence of ovotransferrin is similar to that observed for serum transferrin in many species....
, constituting 12% of the egg white, starts its denaturation and the egg white starts setting. At 80°C, the main protein ovalbumin

Ovalbumin

Ovalbumin is the main protein found in egg white, making up 60-65% of the total protein. While Ovalbumin displays sequence and three-dimensional homology to the serpin superfamily, it is a noninhibitory serpin ....
(54% of the egg white) denaturates. The denaturation and rearrangement at 80°C has caused the egg white to be firm.

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

Denaturation (biochemistry)

Denaturation is a process in which proteins or nucleic acids lose their structure by application of some external stress or compound for example, treatment of proteins with strong acids or bases, high concentrations of inorganic salts, organic compound solvents , or heat....
. 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.

Stabilizing egg white foam for culinary purposes

Copper Bowl

Copper

Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity....
bowls have been used in France

France

France , officially the French Republic , is a country whose Metropolitan France is located in Western Europe and that also comprises various Overseas departments and territories of France....
since the 18th century to stabilize egg foams. The copper in the bowl assists in creating a tighter bond in reactive sulfur

Sulfur

Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant Valence non-metal....
items 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.

Adding an acid

Cream of tartar (potassium bitartrate) is an acid

Acid

An acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion Activity greater than in pure water, i.e....
ic salt that can be used to change the pH

pH is a measure of the Acid or Base of a solution. It is defined as the cologarithm of the Activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations....
of 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.

Works cited

Elmhurst College
Elmhurst College

Elmhurst College was founded in 1871. It is a private four-year institution affiliated with the United Church of Christ. It is located on 38 acres of land in Elmhurst, Illinois, a suburb of Chicago....
,
Exploratorium
Exploratorium

The Exploratorium is a public science museum museum, located in the Marina District at the Palace of Fine Arts in San Francisco, California. It is one of San Francisco's most popular museums, drawing over 500,000 people each year....
,
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, . DVD. Television Food Network, June, 13 2001.
McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. New York: Scribner, 2004.

Egg white

Composition

Uses

Nutrition

Denaturation

Egg white foam

Creating an egg foam

Stabilizing egg white foam for culinary purposes

Copper Bowl

Adding an acid

Works cited

See also

External links