Emulsifiers

The use of emulsifiers in foodstuffs began in 1870 for the production of margarine. Industrial production of food emulsifiers then began (Dominic, 1986). The total global production of emulsifiers is estimated at about 200-150,000 tons (William, 1975). This value includes twenty different groups of emulsifiers. Emulsifiers are naturally occurring (lecithin) and can also be produced synthetically. Emulsifiers were divided into different groups and have different properties in food. These compounds are found in most raw as well as processed foods. Glycerols and phosphatides, for example, are important components of the cell wall of living cells, and glyceroglycolipids are the polar fats of green plants. Mono- and diglycerides are also intermediates in the biosynthesis or breakdown of plant and animal fats.

Natural emulsifiers play an important role in food production and metabolism and their conversion into energy sources (Pomeranz, 1984).

Emulsifiers are compounds that have an active surface, dissolve or disperse in the liquid, and are usually adsorbed on the particle surface, causing significant physicochemical changes. The molecular structure of these compounds is such that there are simultaneously hydrophilic (hydrogel or lipophobic) and hydrophobic (hydrophobic or lipophilic) components in their structure (Dominic, 1986).

Part of the emulsifier molecule binds to polar compounds or groups and part to non-polar compounds. The polar groups or main groups of these compounds have a special electronic arrangement and bipolar moment, this polar group absorbs liquids and is the hydrophilic part of these compounds. Nonpolar groups are the organic part of the molecule and their electron distribution is such that there is no significant interpolarity. This component of the molecule has a strong affinity for non-polar liquids and low-polar organic solvents. The presence of hydrophilic and hydrophobic groups in the molecule allows the emulsifier to combine with aqueous and organic solvents. One of the most important applications of emulsifiers is emulsion preparation (Pomeranz, 1984). An emulsion is a system in which two different phases are distributed and distributed. These two phases do not mix under normal conditions (Dominic, 1986).

According to the World Committee of Pure Applied Chemistry, droplets or crystals are dispersed in another liquid in one emulsion. Emulsions are divided into macro and micro emulsion categories. This classification is based on the size of the particles scattered in the continuous phase. If the continuous phase is water, and the diffused phase is oil, the emulsion is of oil-in-water type and its properties are similar to water. In water-in-oil emulsions, the continuous phase is oil and the diffuse phase is water, and its properties are similar to those of oil.

The effect of emulsifiers during bread storage and delaying bread staleness

The effect of emulsifiers depends on the proper distribution of these compounds in the dough before starch gelatinization (Valjakka et al, 1994).

As the bread cools, changes take place in it, which are called stale bread. These changes include the following:

1- Change in the flavor of bread

2- Increasing the firmness of bread crumbs

3- Blurred or opaque bread crumbs

4- Reducing the effect of beta-amylase anime on bread crumbs

5- Crystallization of starch

6- Reduction of soluble starch

7- Reducing water absorption

Emulsifiers are more important in the production of wheat bread because wheat dough has a larger volume and its walls and pores are more sensitive to mechanical operations. Emulsifiers have the following effects on dough and bakery products.

1- Prevent and reduce the loss of aroma and taste of bread

2- Possibility of preparing different types of bread

3- Delaying the staleness of bread by forming a complex with starch

4- Increasing the volume of bread and improving its aroma and taste

5- Creating elasticity in the texture of bread

6- More strength of walls and pores in bread

7- Improving the structure of bread kernel and its outer shell

8- Improving and increasing the digestibility of bread

9- Uniformity of bread color

10- Improving bread cutting ability

11- Preventing the activity of mold and roping of bread (ropen)

12- Increasing the storage capacity of gas in the dough

13- Improvement and ease of mixing and mechanical operations in the dough

14- Increasing the amount of water absorption in the dough

15- Increasing dough tolerance to changing raw materials

16. Reducing the need for shorting (Pomeranz, 1984).

Emulsifiers with all flour compounds that are effective in stagnation; Combined and in different stages of preparation of bakery products create important and different effects.

Emulsifiers prevent water from being absorbed by the granules by being on the surface of the starch granules and reacting with them. Emulsifiers affect the durability and strength of air cells between starch and gluten granules. The effect of emulsifiers on the dough depends on the surface activity and dispersion of these compounds in the dough. These compounds cause the dough to become uniform, reducing the time and energy required to mix the dough (Pomeranz, 1984).

By adding water to the flour and mixing it, the emulsifiers begin to combine with the proteins of the fats and starches. This step is very important in the reaction and combination of polar fats and emulsifiers with proteins, as well as the formation of non-covalent bonds. With the formation of these bonds, the quality of gluten is improved and the tolerance of dough mixing is increased (Pomeranz, 1984).

Consumption of emulsifiers, especially monoglycerides with hydrogenated fats, has interesting effects on bread.

Polar fats of flour, in the dough forming double-layered plates or phases