CAKE

Cake and cake like products are produced from batters using rich formulas characterized by a high level of sugar, variable levels of fat,baking powders, emulsifiers, preservatives, milk, and also cocoa powder, nuts, fruits, icings, and certain flavorings are used for special cakes.
A light, porous structure has the desired eating characteristics of most cakes,while some cake formulas are more dense. For example brownies have a more dense structure since they are made without baking powder.
To produce a cake with an open structure and high volume, a procedure and recipe is needed to create a stable batter with many tiny air bubbles.
These bubbles grow in size when the carbon dioxide gas generated by the function of baking powder. There is a difference between gas retention of cake and bread. For bread-like products, structure depends on the quality and quantity of the gluten protein in the flour and its function in dough. For cakes there are basically two different methods to produce a high-quality batter that can be baked into a cake with an acceptable volume and grain.
1)The multi-stage mixing method is based on creating a stable batter with many tiny air bubbles through a creaming step,whose aim is to incorporate air into the fat, in which fat and sugar are mixed together to form a cream. This method is generally used in productiın of commercial pound cake
2.The single-stage mixing method is based on incorporating air directly into the aqueous phase in a single step called as mixing,whipping or beating. Both eggs and emulsifiers are important ingredients for stabilizing agents used in the singlestage mixing method. This method is generally used in the production of foam-type cakes.
There are some igredients essential to cakes:
Eggs, egg white (ovalbumin), are important foam stabilizers, which slow down the coalescence ,which is the most dominant mechanism to disappear air bubbles in a single stage.
When a lot of air has been incorporated to form a light, fluffy batter, the lamella separating the individual air bubbles become extremely thin and will therefore easily rapture. Many proteins, especially egg white protein, are able to unfold (denaturate) at the liquid water interface of the air bubbles and stabilize the thin lamella between the bubbles. The foam-stabilizing effect of egg white is used in the production of meringues.
Shortening and oil are used in cake formulas to give a more tender structure and to avoid the dry mouthfeel of sponge cakes made without fat. Shortening and oil are important foam destabilizers. The shortening and oil particles that are larger than the thickness of the lamella separating the air bubbles in a foamed batter will destabilize the lamella and cause a foam to collapse quickly.
The foam-destabilizing effect of shortening can be reduced when the oil-containing material is carefully folded in with the foamed egg white. Another way to reduce the foamdestabilizing effect of shortening or oil particles is binding the fat or oil to the flour.
Emulsifiers are also useful for reducing the foam-destabilizing effect of fat in foamtype cakes by emulsifying the fat. The emulsified fat particles remain well-dissolved in the aqueous phase. They do not destabilize the thin foam lamella between the gas bubbles. Emulsifiers help to produce a foam-type cake of acceptable quality.
Baking powder provides the porous structure for cakes and also changes color and pH of the cake mixture.
Flour used for cakes is different from flour that for bread.Because gas retention in cakes does not depend on gluten, and usually flour with a low protein content is preferred for cakes. Because flour particles do not disintegrate to the same extent during batter formation as during dough mixing, a finely ground flour is preferred.

DISAPPEARING BUBBLES

Bakery products are characterized by a typical porous structure and a high specific volume. To obtain the porous structure, air bubbles are incorporated during a mixing or blending step.Therefore gas retention and final volume of the baked good depend on how fast these bubbles disappear again.
Bubbles are disappeared by the following processes:
Buoyancy is the process by which bubbles rise to the surface and is driven by a difference in density between the gas and the liquid phase.
Disproportionation is the process by which larger bubbles grow while smaller bubbles gradually disappear.
Coalescence is the process by which the thin lamella between two adjacent bubbles collapses to form one bigger bubble. Coalescence is more important than disproportionation and buoyancy because gas retention is maximized by stabilizing the lamella between the bubbles.
A food additive is anything added to a food and they are used in foods for one or more of the following reasons.
1.To maintain or improve nutritional value
2.To maintain freshness
3.To help in processing or preparation
4.To make food more appealing

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