MERINGUE

  • Meringue is a type of dessert or candy, often associated with Italian, Swiss, and French cuisine,
  • traditionally made from whipped egg whites and sugar, and occasionally an acidic ingredient such as lemon, vinegar, or cream of tartar.
  • A binding agent such as salt, flour, or gelatin may also be added to the eggs.
  • The key to the formation of a good meringue is the formation of stiff peaksby denaturing the protein ovalbumin (a protein in the egg whites) via mechanical shear.
  • Meringues are often flavoured with vanilla, a small amount of apple juice, or orange juice, although if extracts of these are used and are based on an oil infusion, an excess of fat from the oil may inhibit the egg whites from forming a foam.
  • They are light, airy and sweet confections. Homemade meringues are often chewy and soft with a crisp exterior, while many commercial meringues are crisp throughout. A uniform crisp texture may be achieved at home by baking at a low temperature (80–90 °C or 176–194 °F) for an extended period of up to two hours.
  • It has been claimed that meringue was invented in the Swissvillage of Meiringen and improved by an Italian chef named Gasparini between the end of the 17th century and the beginning of the 18th century. However, this claim is contested; the Oxford English Dictionary states that the French word is of unknown origin. It is sure nevertheless that the name meringue for this confection first appeared in print in François Massialot‘s cookbook of 1692.

Types of Meringue

There are several types of meringue: the sweetened, beaten egg whites that form the “islands” of floating island (also known in French as île flottante); the partly cooked toppings of lemon meringue pie and other meringue-topped desserts; and the classic dry featherweight meringue. Different preparation techniques produce these results.

  • French meringue, or basicmeringue, is the method best known to home cooks. Fine white sugar (caster sugar) is beaten into egg whites.
  • Italian meringueis made with boiling sugar syrup, instead of caster sugar. This creates a much more stable soft meringue which can be used in various pastries without collapsing. In an Italian meringue, a hot sugar syrup is whipped into softly whipped egg whites until stiff, and until the meringue becomes cool. This type of meringue is safe to use without cooking. It will not deflate for a long while and can be either used for decoration on pie, or spread on a sheet or baked Alaska base and baked.
  • Swiss meringueis whisked over a bain-marie to warm the egg whites, and then whisked steadily until it cools. This forms a dense, glossy marshmallow-like meringue. It is usually then baked.
  • Vegan meringueis imitation meringue made using aquafaba with a small dose of vinegar and caster sugar. It holds similar characteristics to that of egg-based meringue, but it will quickly burn if torched or baked incorrectly. Another variation uses potato protein instead of aquafaba.

Compound interactions

  1. There are three main ingredients in a meringue recipe that interact to form the foam structure, egg whites, sugar, and cream of tartar or acid.
  • The backbone of the foam structure is made up of proteins, amino acid chains.
  • Egg whites provide the meringue with necessary proteins that form the meringue foam. The proteins are originally oriented in a tangled ball but must be uncoiled into strands; this is referred to as denaturation.
  • There are two ways a protein can be denatured, through physical or chemical process. When forming a meringue the egg whites are beat until the proteins are denatured, a physical process. Also by beating the egg whites, air is incorporated into the protein structure creating an air-water protein mixture interface.
  • The friction from beating the eggs adds heat to the process, which causes the proteins to increase in elasticity. As the proteins are being stretched during the denaturation process they are also coagulating together forming a protein network.
  • After the denaturation process the egg whites will become six to eight times their original size. If the proteins are beat for too long they will become stretched out too far and become too weak to support the foam structure.

2. Cream of tartar:

  • Also known as potassium hydrogen tartrate, KC, 4H, 5O 6, is added to the egg whites before the denaturation process.
  • Cream of tartar is an acid that is used to help stabilize and coagulate the proteins, which aids in a stronger protein network to trap air for the foam formation. Cream of tartar has a low pH to help bring the proteins near their isoelectric point to allow them to be denatured easier. The isoelectric point is a specific pH where a molecule, in this case protein, has no net electrical charge. The electrical charge on a protein would normally hold the protein together in its coiled clump.[10]
  • The cream of tartar also acts as a catalyst affecting the sugar structure. Sucrose is a disaccharide made up of glucoseand fructose. Cream of tartar inverts the sugar during the baking process, meaning the molecule is split into two parts containing glucose and fructose. This prevents the sugar from recrystallizing and giving the meringue a gritty, undesirable texture.

3. Sugar:

  • Sugar is the final ingredient that is used to help form and stabilize the foam structure.
  • Sugar is hydrophilic, extracting water out of the egg whites. This will lighten the protein network, allowing the foam to be stronger and more elastic. The sugar dissolves in the protein network but does not become part of the protein network. The sugar must be added slowly to the egg whites, while continuously mixing. If it is added all at once, it will not be evenly distributed, causing the protein network to collapse due to the weight of the sugar in one area of the meringue.
  • After a strong protein network has formed a complete foam, the meringue is ready to be baked. Adding heat to the mixture is the final step to strengthen the foam structure. The meringue must be baked at a low temperature for a long period of time. This allows the proteins to finish coagulating, strengthening the meringue evenly throughout. If the proteins are not baked evenly, the bottom of the meringue will not be able to support the structural weight, causing the meringue to collapse. The heat causes the air bubbles to expand, creating an airier structure. The water in the structure evaporates, causing the meringue to become lighter with a stronger foam structure. It is important to not evaporate all of the water out of the meringue, as some water is necessary to hold the foam together.