Do you know the role of emulsifier in cake and bread?

In baking products, there are two kinds of materials: water and oil, especially in cake, the proportion of oil and water is more than bread, but oil and water can not be mixed with each other. Put oil and water in a test tube and cover it with force and shake it, then the oil and water will be mixed together into small particles evenly. But after standing for a few minutes, the oil and water particles, each of them looking for its own particles, gradually become larger particles, oil and water begin to separate again, and the water floating on the oil sinks, because the water has a greater specific gravity than the oil.

But when oil and water mix, add emulsifier after shock, oil into very small particles evenly distributed in the water without separation, the formation of a uniform solution, this effect is called emulsification, this solution is called emulsion. Anything that keeps oil and water together is called an emulsifier, which changes the way in which two liquids mix and so is called a surfactant, or surfactant for short, because an emulsifier acts on the surface of both liquids.

> 01 emulsifier

There are two ways of emulsifying,One is emulsification soluble in water,oil into small oil particles distributed in water, oil as a dispersed phase, and water as a connecting phase, the solution can conduct electricity.Another is the emulsification of water dissolved in oil, water into small particles dispersed in the oil, water as the dispersed phase, and oil as the connecting phase, the solution can be electrified but not conductive.

As mentioned above, the oil and water are placed in the test tube with a strong shock, and the force does "work" on the oil and water. The surface conditions of the oil and water are damaged, and the oil and water are changed from medium and small surface areas to large surface areas, that is, from large particles to small particles, and mixed with each other. Oil and water turbulence mixing together temporarily, but after sit down, naturally released by high energy and low energy can, do "work" is a kind of natural energy and lose, the phenomenon of oil-water mixture began to destroy, to recover before shock equilibrium, so the liquid has reduced the minimum area of the power of this force is calledSurface tension。

The greater the surface tension of the mixture, the smaller the work required, the easier it is to mix and not easy to separate. When the emulsifier is added to the oil and water, the surface tension of the two can be reduced, and the work must be done to reduce the mixing of the two.

> 02 Principle of emulsifier construction

There are many types of emulsifiers, but the basic principle of their construction is the esterification of compounds containing polyalcohol roots with compounds of fatty acids. Compounds containing polyalcohol roots, such as glycerol, sugar, etc., can interact with fatty acids to produce emulsifiers of many different properties, and at the same time for the hydrophilicity of polyalcohol roots, but also add substitution to make them more ionizable.

Emulsifiers have common properties, such as monoglycerides,Monoglycerides are compounds formed by the esterification of glycerol and fatty acids, Glycerine can be mixed with water in any proportion without natural decomposition.Because the alcohol root of glycerol is polar, can be hydrophilic with water, is hydrophilic. Fatty acids are insoluble in water, but soluble in non-polar compounds, and can be hydrophilic with oil to lipophilic.

Emulsifiers consist of polyalcohol compounds esterified together with fatty acids and thus possess both properties.Emulsifier is also like a zipper, the oil and water together, but the hydrophilicity and lipophilicity of emulsifier, these two forces are not the same for every emulsifier, such as the longer the hydrophilic chain or the larger the molecular weight, the stronger the hydrophilic, vice versa.

> 03 Food emulsifier action

Emulsifier used in food, there are a variety of main functions, but the most important is emulsification, emulsifier can make the oily material evenly distributed or suspended in the aqueous solution. Some emulsifiers can form complex bonds with proteins, sugars, starches, and other molecules, and some can even change the crystalline state. Cake batter, margarine and other decorative materials, salad dressings, these products are emulsifying agent. In many foods, emulsifiers are not only emulsifying but also improving the quality and stability of foods.

Emulsifiers act on bread

Emulsifiers are also widely used in baked goods. At the dough stirring stage,Emulsifier can enhance the endurance of dough to mechanical processing, improve the elasticity, toughness, strength and mixing ability of dough, reduce the degree of dough damage, make all kinds of raw materials dispersed and mixed evenly, form homogeneous dough, and improve the water absorption rate of dough.At the dough fermentation stage,The emulsifier can improve the fermentation ability of dough and enhance the gas holding capacity of dough.During the waking stage, a thin film forms on the surface of the dough, which is prone to collapse. The emulsifier improves the waking endurance of the dough and prevents it from deforming. At the same time,Emulsifiers also prevent bread from aging.The bread hardens after a few days because the starch ages. Emulsifiers are also ideal bread preservatives and anti-aging agents. In the production of bread, emulsifiers can protect the starch grains and prevent aging, thus improving the taste of bread and also helping to extend the shelf life of bread.

The emulsifier is applied to the cake

Used in cake production of emulsifier is usually referred to as oil, emulsion cream or paste composite emulsifier, foaming agent is mainly composed of glycerol and fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sucrose fatty acid ester emulsifier and solvent such as water, propylene glycol, sorbitol of several kinds of preparation.

Add the cake oil to the batterIt can make the cake slurry rise quickly when beating, and make the cake slurry wrapped in a large amount of air in a short time,A fine and rich foam is formed, and then a cake with large volume, fine structure and soft texture is obtained by baking. In addition,The emulsifier can interact with the starch in the cake to form insoluble compound, which can effectively inhibit the aging of starch and make the cake keep soft taste in the long shelf life.Emulsifiers also interact with the fats and proteins in the cake to increase the rise and taste.

> 04 Emulsifier classification

There are four categories of properties of emulsifiers:

① Electricity price of emulsifier dissolved in solution  

② Solubility in various solvents  

③ HLB  

④ The type of root carried by the emulsifier

1. dissolved in solution emulsifier with the price:

The price of the emulsifier in the aqueous solution is divided into anionic, cationic and non-ionic. If be anionic sex emulsifier, namely this kind of emulsifier is dissolved in water when the formation of anion, anion is water-soluble, if be anionic emulsifier, cationic is formed inside water, cationic is water-soluble, non ionic sex emulsifier does not form ion inside aqueous solution.

2. Classification according to solubility:

The solubility of the emulsifier in water and oil. If the emulsifier is soluble in oil, it is a lipophilic emulsifier or a hydrophobic emulsifier. If soluble in water, it is hydrophilic emulsifier, or oleophobic emulsifier, which does not dissolve in oil.

3. Classification by HLB value (hydrophilic and lipophilic equilibrium value) :

This classification is the most widely used. HLB is the balance between hydrophilicity and lipophilicity, which is theoretically the ratio of the molecular weight of the hydrophilic part of the emulsifier to the total molecular weight. Therefore, its formula can be written as follows:HLB=a/b×20   A is the molecular weight of the water part   B is the total molecular weight       The smaller the HLB value, the higher the lipophilicity of emulsifier. The higher the HLB value, the higher the hydrophilicity of emulsifier。

When the HLB value is between 3.5 and 6, it is suitable to be used as the emulsifier of W/O type emulsion. With HLB value between 8 and 18, it is suitable to be used as emulsifier for oil-in-water (O/W) type emulsions. But this is only a general empirical estimate, and the fact often has a large deviation. Practical application or according to the experiment to determine the use of the type and ratio.

4. Classified by its different roots:

Each emulsifier has two parts, the hydrophilic part and the oleophilic part, and then you use a formula based on the hydrophilic roots, and you add up the number of hydrophilic roots minus m, which is the number of roots per methylene unit, and then you add seven, and that's an experimental formula. Must be compared with theoretical values.

> Emulsifiers found in nature

There are many types of emulsifiers that can be used in food. Some emulsifiers exist naturally. The following are some of the emulsifiers that occur naturally.

onic emulsifiers:Bile salts, phospholipids - lecithin.

Non-ionic emulsifiers:Cholesterol, Sclerophyllin, Monoglyceride.