Kneading dough and education

Testoobrazovaniya process is of fundamental importance, since it is preceded by a number of subsequent operations (forming, baking, decoration and so on. D.), In the preparation of specific finished products.
The structure of baked products is formed mainly at the stage of dough formation. The uniformity of the structure of the dough achieved, the degree of its orderliness and, consequently, the quality of the dough and finished products depend on the quality of the system obtained in the process of forming the structure of the dough.
Basics testoobrazovaniya
For the production of flour confectionery in the confectionery industry used dough of various kinds. Each type of dough is prepared according to its technology, which provides the finished product with the desired properties.
The classification structure of the dough
By the nature of the structure of the dough of various types of flour confectionery can be divided into three main systems:
  • elastic-plastic-viscous system (protracted, galetnoe, cracker dough);
  • plastic-viscous system (sugar, shortbread dough);
  • semi-structured systems (waffle, biscuit dough).
The first mandatory goal of the dough kneading operation is the formation of a homogeneous system in the whole mass consisting of flour, water, sugar, fat and other components.
The main thing in the process of dough formation is the formation of the required dough structure and the production of a system with the desired properties.
At the beginning of the dough kneading flour comes in contact with water, sugar, fat, salt and other components. In this case, a series of processes begins to occur in the resulting test. Physical, colloidal, and biochemical processes are most important.
Microbiological processes associated with the vital activity of yeast and acid-forming bacteria of flour, in the process of kneading dough, do not yet have time to reach the intensity at which they could play a decisive role.
Each of the raw materials that form a complex dough system in the complex plays a certain role in the process of dough formation, but the main raw material is most important - flour, fat and sugar.
The impact on the process of flour testoobrazovaniya
In the production of flour confectionery products, wheat flour of the highest and I grades is used predominantly, and for certain types of products, wheat flour is used (Table 6).
Table 6
Flour
Krupnota grinding%
Ash content,% on CB, not more than
gluten content,%, not less
Sieve residue (silk or wire)
Pass through a sieve (silk or wire)
number sieve
no more, %
number sieve
%
Wheat
the highest grade
43
5
0,55
28
| Sorts
35
2
43
0,75
30
|| Sorts
27
2
38
At least 60
1,25
25
wallpaper
067
2
38
At least 30
20
* No less than 0,07% lower ash content of grain before cleaning.
When kneading dough, flour particles begin to quickly absorb water, swelling at the same time. The adhesion of the swollen particles of flour into a solid mass, resulting from the mechanical impact on the kneaded mass, leads to the formation of dough.
The leading role in the formation of dough with its inherent properties of elasticity, plasticity and viscosity belongs to the protein substances of flour. Water-insoluble flour protein substances that form gluten (gliadin and glutenin) bind water in the dough not only by adsorption (surface), but also osmotically. Osmotic swelling occurs as a result of the diffusion of water molecules into the cell of the protein molecule. Osmotic binding of water mainly causes swelling of proteins. Gluten proteins can swell in cold water and retain water in amounts that are approximately 2 — 2,5 times its mass.
When batching, swollen protein substances form a spongy “carcass” in the dough, which largely determines the specific physical properties of the dough - its extensibility and elasticity.
This protein spongy structural framework is often called gluten.
The interaction of proteins with water consists of two main steps, is closely linked.
The first stage of swelling consists in the adsorption binding of water to form water shells around the flour particles. In this case, the interaction of water with hydrophilic groups occurs not only on the surface of the flour particles, but also inside them. The first stage of swelling is exothermic (that is, with the release of heat) process and is not accompanied by a significant increase in the volume of particles, since the amount of water bound in this way is about 30%.
The second stage is the so-called osmotic swelling, which occurs as a result of the diffusion of water molecules into the particles of flour.
The second stage of swelling proceeds without the release of heat, but with a significant increase in the volume of micelles, since the amount of water bound in this way by proteins is more than 200%. Most proteins, including gluten proteins, are not homogeneous, but are a complex of different fractions with different molecular weights and different water absorption capacity.
Starch is the main constituent of the quantity of flour. Wheat flour contains about 70% starch. Therefore, the content, condition and properties of starch significantly affect the physical properties of the dough and the “strength” of the flour.
"The strength of the flour" - is the ability of flour to form a dough, which has after kneading and in the process of further technological processing certain physical properties.
"Strong" it is accepted to call flour capable of absorbing a relatively large amount of water when kneading dough of a normal consistency. The dough from the "strong" flour is very stable retains its physical properties in the process of kneading and further processing.
"Weak" consider flour, which, when kneading dough of normal consistency, absorbs relatively little water. The dough from such flour in the process of kneading and technological processing quickly changes its physical properties in the direction of relaxation of the consistency.
"Average" By its strength, the flour, according to the described properties, occupies an intermediate position between the “strong” and “weak” flour.
Starch basically includes two carbohydrates: amylose and amylopectin.
Amylose is relatively easy to dissolve only in warm water (over 40 ° C), forming a true solution. Amylopectin is soluble in water only when heated under pressure. Therefore, due to the strong structure of starch and the low solubility of its fractions, the amount of bound moisture in it is relatively small.
Flour moistened starch with water can adsorb to 35 — 40% moisture at room temperature.
At higher temperatures and sufficient water binding starch with water increases.
The more grain and, accordingly, starch flour, the lower the protein content and the "weaker" the flour. However, the physical properties of the dough are influenced not only by the starch content in the flour, but also by its properties, in particular, the sizes of starch grains and the degree of their damage when grinding the grain. The finer the grains, the greater their specific surface and the more water they will adsorbate with them during the formation of the dough. This means that the dough made from flour with smaller grains of starch or a large percentage of its small grains will be more viscous with the same water content. Whole grains of starch bind water mainly by adsorption, up to a maximum of 44% for dry matter, so their volume in the dough increases very slightly. Damaged starch grains can absorb up to 200% water. Due to the significant quantitative prevalence of starch in flour (its content reaches 70%), the moisture is almost equally divided by the proteins and starch of the flour.
In dough from a large yield of flour, for example, wallpaper, a significant role in the binding of water is also played by the particles of the grain shells (branded particles), which adsorbably bind moisture due to the presence of a large number of capillaries. That is why the moisture capacity of such flour is increased.
An increase in temperature and the presence of a sufficient amount of moisture contribute to an increase in the binding of starch to water. At temperatures above 60 ° C and an excess of water, the starch gelatinization process takes place, i.e. the structure of starch grains is disturbed and a colloidal solution is formed.
Starch moistened with water in any ratio and in any situation, does not form a bound test.
Starch grains, shell particles and swollen water-insoluble proteins make up the “solid” phase of the dough.
Along with the solid phase in the dough, there is also a liquid phase, which is a part of water that is not bound by adsorption by starch, proteins and particles of grain shells. It contains water-soluble substances of the dough - mineral and organic (water-soluble proteins, dextrins, sugars, salts, etc.).
The liquid phase of the dough may be partially in the form of a free viscous liquid surrounding the elements of the solid phase (swollen proteins, starch grains and particles of grain shells). In wheat dough, a significant portion of the liquid phase can be osmotically absorbed by swollen dough proteins.
Along with the solid and liquid phases, there is a gaseous phase in the dough. The gaseous phase arises due to the capture and retention by the dough of air bubbles in which the atmosphere is kneaded, as well as as a result of the fermentation process.
The influence of other primary commodities in the process testoobrazovaniya
Dough for pastry products besides flour contains water and other raw materials, particularly sugar and fat.
Sugar reduces the swelling of protein flour and has a significant impact on the structure of the dough and the quality of the finished products.
Sugar, affecting the taste and color of products, in addition, has the ability to limit swelling, so that it becomes possible to regulate the degree of swelling of proteins and flour starch. Therefore, sugar is a plasticizer dough.
Permissible deviations in the formulation of sugar in the dosage allow to take into account the properties of the flour and the temperature.
When there is an excess of sugar, the dough pieces spread out and become sticky, which leads to dough adhesion to the rolling, forming mechanisms, as well as to the steel tape of the baking chamber.
The presence of large amounts of sugar in the dough products without fat gives excessive hardness.
A large influence on the quality of dough and products has the size of sugar particles. To obtain plastic dough, in which the water content is sharply limited, it is necessary to use sugar, not sugar, but sugar. This is due to the fact that in a relatively small amount of water all the amount of sugar provided by the recipe cannot be dissolved and the remaining undissolved sugar crystals remain visible on the surface of the biscuit, which degrades its quality.
Fats injected into the dough also lower the swelling of the flour colloids. By adsorptive binding to starch and proteins, fats block possible places of adhesion of colloidal particles, weaken the mutual connection between them and thereby prevent the penetration of moisture. This helps to reduce elasticity and increase the plasticity of the dough.
Depending on the type of fat used, the mechanism and effect of plasticization change significantly.
Greases have the greatest advantage, preserving plasticity with a large temperature range. This is usually achieved by combining solid and liquid fats with different melting points. In this case, with a slight increase in temperature, only part of the fat melts, as a result of which the fat retains its plastic properties.
In the process of kneading dough, the fat particles in the form of thin films are distributed between the flour particles, as if enveloping and lubricating them. When baking dough interlayer fat between the particles * flour contribute to the formation of a porous structure and fragility of the finished products. The thinner the film of fat and the more of them in the dough, the more porous and fragile structure will have finished products. From this point of view, the kneading of the dough on a dispersed, well-knit emulsion, in which the fat is distributed in the form of the smallest droplets, significantly contributes to the formation of a good product structure. If the fat is collected in the dough in the form of large droplets or balls, it does not envelop the flour particles, is poorly retained by the products and is released from them during storage. So behaves, for example, liquid vegetable oil. Solid high-melting fat has a high viscosity and low plasticity and is also poorly distributed among the flour particles, collecting in large aggregates. In the dough, only fat is well distributed, having good plastic properties at certain indicators, namely fat, which retains plasticity in a relatively wide temperature range.
The presence of fat in the finished products gives them a layered and crumbly character. With an increase in the amount of fat, the dough becomes loose, crumbling, and with a decrease, the plasticity of the dough decreases, finished products are less crumbly.
The dispersion of fat has a great influence on the quality of products. The higher the dispersion of fat introduced into the dough, the more active its influence. Therefore, it is better to make the fat in emulsified form.
Dairy products improve the plasticity of the dough and taste of products due to the presence in them of a well emulsified milk fat.
Egg products promote foaming and loosening of the dough: yolk lecithin is a natural emulsifier, and egg albumin, due to its good foaming properties, makes the products porous and contributes to the fixation of the structure. In addition, egg products give products a pleasant taste and color.
Molasses, invert sugar and honey in the production of flour confectionery products are used to increase the wettability and impart a golden-yellow color to the surface of the products, which is caused by the decomposition of monosaccharides in the baking process.
Certain properties of the dough are achieved by various technological conditions of the batch and a set of raw materials in the recipe.
By adjusting the process of kneading dough by introducing into the recipe various amounts of sugar, fat and other components, you can get a dough with predetermined physical properties.
The amount of water introduced into the dough, the temperature of the mixture during the kneading, the duration of the kneading also determine the physical properties of the resulting dough. Changing technological factors (humidity, temperature, duration of kneading) and recipe, in practice they get confectionary dough, which has various properties: from elasto-plastic to viscous for long cookies, cracker and biscuits to liquid semi-structured - waffle; from plastic to sugar and shortbread biscuits to downed, air-saturated sponge cake.
The use of fat and sugar kneading creates conditions for a low humidity test, as it requires less water for the limited swelling of flour proteins.
More sugar and fat in the sugar dough, low temperature and a short kneading limit the swelling of gluten proteins.
Kneading of long, cracker and galetny dough creates conditions for a more complete swelling of the flour proteins and, consequently, the production of elastic dough. This is also facilitated by a smaller amount of sugar and fat in the recipes of these types of dough, high humidity and temperature, and a longer kneading compared to sugar dough.
Biscuit and waffle dough belongs to the group of weakly structured systems, and the preparation of these types of dough has its own specific, sharply distinctive features.
Biscuit dough is a dispersed system, which consists of air bubbles separated from each other by films of dispersion medium of very small thickness. The process of making biscuit dough is the introduction of dispersed air into the dough. In this case, a significant increase in the mass volume occurs (in 2,5 — 3 times), accompanied by the development of the internal surface of the system.
According to its structure, biscuit dough is a highly concentrated dispersion of air in an environment consisting of egg products, sugar and flour. Therefore, biscuit dough can be attributed to foams.
Waffle dough also belongs to the group of weakly structured systems. It should have a liquid consistency, which ensures the normal dosage and rapid distribution of the dough on the surface of the flat wafer forms of the oven. To obtain a wafer dough of a liquid consistency, technological conditions are created during dough kneading, which limit the sticking together of separate scattered particles of gluten from flour.
Rheologically, wafer dough is a slightly structured dispersion system. The dough is kneaded so that at the moment of contact with the liquid around each flour particle a hydrated shell is formed, which prevents the swollen particles of gluten from coming together and sticking together.
Influence of the basic technology factors the process of testoobrazovaniya
Technological factors of production, first of all, temperature, humidity and duration of mixing, have a great influence on the physical and structural-mechanical properties of the dough.
HUMIDITY TEST
Humidity test depends on several factors, primarily the water absorption capacity of flour, sugar and fat in the recipe.
Flour water absorbing capacity - is the amount of water required for kneading the dough consistency optimal to enable normal handling of the test at all production phases.
The water absorption capacity depends on the moisture content of the flour, the yield and coarseness of the grinding, as well as the content of proteins in it.
When the moisture content of flour decreases by 1%, the water absorbing capacity of flour increases by 1,8 — 1,9%. With increasing yield of flour, water absorption capacity increases.
The particle size of the flour and its dispersion also affect the water absorption capacity of the flour. The larger the flour particles and the more heterogeneous their composition, the smaller the specific surface area and the less water that is bound by the flour over a certain period of time.
Sugar has a great influence on the water-absorbing ability of flour. As the amount of sugar increases, the water absorbing capacity of the flour decreases. So, when 1% sugar is added, the water absorbing capacity of flour is reduced by 0,6%.
When kneading dough, the dependence of the water absorbing ability of flour on the main factors should be taken into account. This will allow the most correctly determine the ratio of raw materials and water for each type of dough.
Indicative calculation of the amount of water required for kneading is carried out according to the formula
X - [100S / (100-A)] - B,
wherein X - the amount of water per batch in kg; C - weight of dry matter of raw material in kg; A - the desired test humidity,%; B - the mass of raw material per batch (without added water), kg.
Under production conditions, the water dosage during dough kneading needs to be specified for each type of product separately, depending on the recipe and the water absorbing capacity of the flour.
Dough moisture control is carried out at the beginning of the kneading, since the addition of flour or water to the already formed dough will not allow for an even distribution of the added raw materials in the dough mass due to the presence of a well-formed dough structure.
The moisture was experimentally determined for each type of dough, which varies depending on the water absorption capacity of the flour, sugar content and fat.
The humidity of the dough of each product group depends on the formulations used. In dough made from high-grade flour, humidity is lower than in dough made from lower-grade flour.
Within each category are also provided vibrations dough moisture, since the individual products are different varieties of sugar and fat.
TEMPERATURE TEST
Temperature has a significant impact on the process of dough formation, accelerating or slowing the swelling of flour colloids. If it is necessary to increase the swelling of the flour colloids, the kneading is carried out at an elevated temperature, if it is necessary to limit the swelling and to obtain a plastic dough (for example, when kneading sugar dough), the process is carried out at a low temperature of the raw material mixture.
For each type of dough there is a optimum temperature.
So, for sugar and shortbread dough, the optimal temperature is 22 — 25 ° С, for long-lasting - 38 — 40 ° С, for tart and cracker - 32 — 35 ° С.
Dough processing with a temperature of 32 — 40 ° C should be carried out in a room where the air temperature is not lower than 20 ° C. At a room temperature of about 15 ° C, the surface of the dough with a temperature of about 40 ° C deteriorates markedly (becomes rough), which negatively affects the appearance of the products. Therefore, when processing dough in a cold room, the dough temperature should be slightly lower than normal.
The desired temperature of the mixture can be given a prescription by adjusting the temperature of water or milk, going to the batch.
In order to determine the required temperature for heating milk or water, calculate the amount of heat C? (in j), which should be made or taken away when mixing.
The quantity of heat is calculated using the following formula:
Q = mС (t1—t),
where m - mass of all raw material, kg; C - specific heat of the mixture of raw material, J / (kg-deg); t1 raw material mixture is a given temperature, ° C; t - temperature of the mixture of raw materials.
However, the theoretical calculation exceeds the amount of heat that should be made to achieve the desired temperature of the test. This is explained by the fact that this calculation does not take into account the heat of hydration of proteins and starch of flour, the heat of dissolution of sugar, the heat generated when mechanical energy passes into heat due to friction of the dough on the walls and blades of a kneader, etc.
It is practically established that the amount of heat released due to the above factors is approximately 15% relative to the amount of heat that should be added to the mixture to obtain the desired temperature of the test.
Therefore, in order not to complicate the calculations, the obtained value of C} is multiplied by 0,85, and then the division is made.
The duration of kneading
The duration of the kneading also has a significant impact on the properties of the dough.
To obtain a test with pronounced elastoplastic-viscous properties (lingering, fillet, cracker), the duration of kneading increases.
To obtain plastic sugar and sand dough, the duration of kneading is reduced to the minimum necessary for uniform distribution of raw materials and the production of associated dough.
The duration of mixing for the same type of test can vary depending on the gluten content of the flour, the raw material mixture temperature, humidity test, the design of blades and kneading machine frequency of rotation.
The rate of dough formation is influenced by the gluten content in the flour, the humidity of the dough, the temperature of the raw materials and the speed of kneading.
With an increase in the amount of gluten in flour, the duration of kneading of the protracted, cracker and wafer dough decreases. With a low gluten content in flour, its more complete swelling is necessary, which is achieved by a longer dough kneading.
Increasing the amount of moisture in the dough, ceteris paribus reduces the duration of the batch due to the more complete swelling of gluten.
The initial temperature of the mixture of raw materials also affects the duration of the dough kneading, as the temperature affects the swelling of the flour proteins. Increasing the initial temperature of the mixture leads to an acceleration of the kneading dough.
Increasing the speed of the blades of the kneader shortens the kneading time. However, for sugar dough, it is not recommended to excessively increase the frequency of rotation of the blades, since the temperature in the dough quickly rises, as a result of which the dough is formed, that is, the plastic decreases in the dough and the elastic-viscosity properties increase.
Methods loosening test
In the confectionery industry for loosening the dough advantageously used three methods: chemical -
with the help of various salts, emitting gaseous substances in the dough; biochemical - using baker's yeast; physical, which uses carbon dioxide (carbon dioxide) or air injected into the kneading or churning machines during the dough preparation process.
A chemical disintegration test method. Chemical disintegrators can be divided into three groups: alkaline, alkaline acid and alkali salt.
Alkaline disintegrators include sodium bicarbonate (sodium bicarbonate), ammonium carbonate (ammonium carbonate), and mixtures thereof; to alkali acid - a mixture of sodium bicarbonate and crystalline food acids or their acid salts; to alkaline-salt - a mixture of sodium bicarbonate and neutral salts, for example a mixture of sodium bicarbonate and ammonium chloride.
Alkaline chemical disintegrating agents are most commonly used at enterprises: sodium bicarbonate (soda) and ammonium carbonate.
Sodium bicarbonate NaHX03 is the most common chemical baking powder. Its loosening effect is manifested when heated, when the baking powder added to the dough decomposes with release of carbonic acid according to the following equation:
2NaNSOz = Na2С03+ N20 + С02.
Sodium bicarbonate as a baking powder has several disadvantages. In free form, only 50% carbon dioxide is released. When carbon dioxide is released, 63% of sodium carbonate is formed (by weight of sodium bicarbonate), which makes the products alkaline. The surface of the products is painted in a yellowish-pink color, and the products acquire a specific flavor.
The other most widely used baking powder is ammonium carbonate (NH4)2С03. This disintegrant produces much more gaseous products.
Ammonium carbonate decomposes when heated to release carbon dioxide, ammonia and water. The reaction proceeds according to the following equation:
(NH4)2С03= 2NH3 + С02 + N20.
Ammonium carbonate is completely decomposed in a kiln with about 82% gaseous substances involved in loosening the dough, and a little more than 18% water vapor.
The disadvantage of ammonium carbonate as a disintegrant is that the products in a warm condition retain the smell of ammonia.
With an excess of baking powder to the product for a long time there is a smell of ammonia.
When using a mixture of sodium bicarbonate and ammonium carbonate, the smell is less intense, while the alkalinity of the products decreases.
The advantage of these disintegrators is that the release of gaseous substances occurs mainly not in dough, but in baking products. This allows the most complete use of carbon dioxide and ammonia for loosening products.
As a substitute of using ammonium carbonate salt NH ugleammoniynaya4НС03. Moreover, its dosage compared with ammonium carbonate increases by 30%.
The reaction proceeds according to the following equation:
NH4HCO3= NH3+ CO2+ N20.
Chemical leavening agents dosed depending on the properties of dough.
So, 0,4% sodium bicarbonate and 0,5% ammonium carbonate are added to sugar varieties of cookies; in the long varieties of cookies - respectively 0,7 and 0,08%.
In order to obtain products of normal porosity, it is allowed to vary the dosages of chemical disintegrators depending on the flour properties: (by weight of the disintegrant) soda by ± 15%. The reduction in ammonium content should not exceed 50% of prescription standards.
Tolerances from the usual doses of chemical disintegrating agents are also possible to regulate the mass of biscuits required for machine wrap. For example, to increase the mass of cookies, respectively, increase the dose of sodium bicarbonate and reduce the dose of ammonium carbonate, and to reduce it, reduce the dose of soda and increase the amount of ammonium carbonate.
If the biscuit is obtained with blisters, change the dose of chemical baking powder. In this case, an increased dose of chemical disintegrating agents eliminates this defect.
It is not recommended to bake cookies using ammonium carbonate alone, as it acquires an unpleasant sweet taste and a pale color, and as a result of the very rapid decomposition of ammonium carbonate, the products are obtained as porous.
It is also impossible to produce cookies using sodium bicarbonate, since a significant amount would have to be spent for loosening. In this case, the alkalinity of the cookies significantly exceeds the permissible sanitary rate.
In addition, sodium bicarbonate paints the surface of the cookie in a yellowish-pink color and gives them a specific flavor.
Along with alkaline acid-base disintegrating agents, which include sodium bicarbonate and any acid, can be used to completely decompose sodium bicarbonate and thus produce products with a neutral reaction.
Loosening test using baker's yeast. In this method of loosening the dough, yeast is used containing a complex of enzymes that ferment the main sugars of the dough and ensure the conversion of monosaccharides into alcohol and carbon dioxide.
As a general rule, apply compressed baker's yeast species Saccharomyces cerevisiae.
Yeast is a single-celled plant microorganism with a complex of enzymes that ensure the conversion of sugars into carbon dioxide and alcohol according to the equation
С6Н1206-2С02 + 2С2Н50Н.
Temperature has a great influence on the yeast fermentation activity. As the temperature rises, the fermentation accelerates, but when the yeast dough is kneaded, the temperature should not rise above 40 ° C, since at the 45 — 50 ° C temperature, zymase (yeast enzyme) is inactivated and the yeast activity decreases.
To accelerate the fermentation can be by increasing the amount of yeast and sugar. However, this results in increased losses of dry matter of raw material resulting from the fermentation of sugar.
During the fermentation process, lactic and acetic acids and a small amount of succinic, malic, tartaric, citric and some other organic acids mainly accumulate in the dough. The optimum temperature for acid-forming bacteria is about 35 ° С.
The mechanism of the yeast fermentation process is described in detail in Chapter VIII «Production of biscuits" - kneading yeast dough.
Physical test method for loosening. The physical method of loosening the dough is provided by introducing an air phase into the dough during its preparation in knocking or kneading machines. As a result, the dough is saturated with gas or air bubbles. During baking at a high temperature, carbon dioxide and air bubbles expand, which results in the formation of porous products.

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