Maltasie Activity compressed yeast
Pressed baker's yeast produced from beet molasses containing sucrose unequally rapidly fermented flour medium in different sugar. Primarily they ferment glucose and fructose, sucrose, and then, is rapidly hydrolyzed to monosaccharides enzyme invertase contained in large amounts in the pressed yeast.
It is therefore believed that only monosaccharides can diffuse into yeast cells.
While in the above environment are sugar, maltose is almost fermented and begins to assimilate yeast cells only when there are n environment monosaccharides and sucrose have fermented. latest content in flour is small, so the brew they fermented dough or for 60-90 minutes. During the long period of preparation of the dough yeast must ferment maltose, formed by the hydrolysis of starch amylase, however, for its assimilation, they must first break down it into monosaccharides.
In the yeast factory, where yeast is grown in a sucrose solution under vigorous air blowing, in the resulting yeast accumulates zimazny active enzyme complex, but there are no conditions for the accumulation and retention in their maltase enzyme. Therefore, frequent compressed yeast, have a greater ability to ferment monosaccharides and sucrose, but bad ferment maltose.
Such yeasts have good buoyancy by
standard, as the latter is caused by a rise in the dough during 50-85 minutes, and for such period of fermentation of sugars sufficient own flour. In the production of the first dough ferments well, and then spent monosaccharides and sucrose, flour, fermentation slows down. Especially bad roam in proofing the dough pieces.
Therefore, for bakery production is not enough to compressed yeast had a good standard lift. To characterize their baking qualities necessary to control maltasie yeast activity. It is expressed in minutes, during which 1 g compressed yeast in 4-5% strength solution of maltose formed during 30 20 ° C ml of carbon dioxide. Quality assessment of compressed yeast in their maltasie activity is shown in Table. 1.
Table 1. The recommended dosage of compressed yeast bread made from wheat flour grade II according to their activity maltasie
| Maltasie activity of the yeast, min | The quality of yeast in terms of the activity of maltase activity | Consumption when yeast dough sponge method,% to the weight of flour |
| 85- 95 | Excellent | 0,5 |
| 96-100 | Excellent | 0,6 |
| 101 - 110 | a good | 0,7 |
| 111 - 130 | satisfactory | 0,8 |
| 131 - 160 | Also | 0,9 |
| over 160 | bad | 1 |
About maltasie yeast activity can also be judged by a three-fold rise test. For this, after the first rise, in which, according to a standard for judging the lifting force obmilayut dough and again put in a thermostat perekladinki for lifting up and then climb repeated a third time. Yeast maltasie with poor activity required for the second and third boom, and particularly for future upgrades, longer than maltasie yeast with good activity.
Maltasie compressed yeast activity depends on the properties of the applied strain and the culturing conditions. It is the higher, the more concentrated nutrient media and better aeration. The addition of starch to the molasses losodsrzhaschtsh substances such as corn steep liquor, significantly increases the activity of maltasie compressed yeast.
When using compressed yeast with high activity maltaznon shortened fermentation sponge on 1-1,5 hours, the duration of the test fermentation ps varies, but the bread quality is improved. Therefore, the high activity of yeast maltasie possible, while maintaining the normal duration of sourdough fermentation, to reduce their consumption. The recommended dosage of compressed yeast to produce bread from wheat flour grade II is shown in Table. 1. said dosage to produce bakery products from wheat flour 1 varieties decreased by 30-50%.
When dough bezoparnym method should be used with yeast maltasie activity not higher
110min as there are no conditions for the activation of the yeast cells during dough preparation. Consumption of yeast in this case is 1,2-1,4% instead of the usual 2%. 1Prodolzhitelnost straight dough fermentation and proofing are not increased.
ОSobienie pressed yeast produced alcohol plants
Bakery industry gets a lot of compressed yeast by distilleries, processing sugar beet molasses. These yeast meet standard requirements, generally have good buoyancy and intensively roam in the initial stage of preparation of dough, but stop fermentation and proofing are not raised dough.
The practice of bakeries showed that activated nanie their preliminary storage in liquid nutrient medium flour, products rich in starch hydrolysis, does not give the desired result. Even with an increase in the duration of proofing bread turns out insufficient, poor quality. Improves the fermentation process in a proofing by adding at least a small amount of liquid yeast, which, thanks to their high activity maltasie significantly enhance the fermentation process in proofing.
Maltasie compressed yeast activity depends on the properties of the applied strain and the culturing conditions. It is the higher, the more concentrated nutrient media and better aeration. The addition of starch to the molasses losodsrzhaschtsh substances such as corn steep liquor, significantly increases the activity of maltasie compressed yeast.
When using compressed yeast with high activity maltaznon shortened fermentation sponge on 1-1,5 hours, the duration of the test fermentation ps varies, but the bread quality is improved. Therefore, the high activity of yeast maltasie possible, while maintaining the normal duration of sourdough fermentation, to reduce their consumption. The recommended dosage of compressed yeast to produce bread from wheat flour grade II is shown in Table. 1. said dosage to produce bakery products from wheat flour 1 varieties decreased by 30-50%.
When dough bezoparnym method should be used with yeast maltasie activity not higher
110min as there are no conditions for the activation of the yeast cells during dough preparation. Consumption of yeast in this case is 1,2-1,4% instead of the usual 2%. 1Prodolzhitelnost straight dough fermentation and proofing are not increased.
ОSobienie pressed yeast produced alcohol plants
Bakery industry gets a lot of compressed yeast by distilleries, processing sugar beet molasses. These yeast meet standard requirements, generally have good buoyancy and intensively roam in the initial stage of preparation of dough, but stop fermentation and proofing are not raised dough.
The practice of bakeries showed that activated nanie their preliminary storage in liquid nutrient medium flour, products rich in starch hydrolysis, does not give the desired result. Even with an increase in the duration of proofing bread turns out insufficient, poor quality. Improves the fermentation process in a proofing by adding at least a small amount of liquid yeast, which, thanks to their high activity maltasie significantly enhance the fermentation process in proofing.
| Index | Unit | Yeast plants | |||
| yeast | alcohol I | спиртового II | |||
| maltasie Activity | min | 155 | 297 | 1000 | |
| Zimaznaya Activity | » | 65 | 23 | 31 | |
| The proteolytic activity of amino nitrogen on 1 billion. Cells | mg | 1,25 | 4,21 | 2,78 | |
| The content of reduced glutathione | mg % | 15,3 | 30,7 | 18,4 | |
Our studies the biological characteristics of yeast have shown that this is due to low activity of yeast maltasie produced
alcohol plants (Table. 2), wherein at zimaznoy activity (determined in the same manner as maltasie, but with the use of glucose), they are not inferior to the yeast, produced by yeast factories.
The intensity of the test recovery in three yeast samples had the same lift as standard. The intensity of the recovery test within the first two hours in yeast, developed yeast and alcohol plants, is almost the same, but further fermentation yeasts distilleries slows. Thus, a legitimate relationship between the lift of yeast standard and maltasie no activity.
Maltasie yeast activity due to the properties of pure cultures used in alcohol production, maltasie their activity and the ability to adapt to maltose. However, the selection of them, unfortunately
uchitytyvayutsya no requirements for compressed yeast baking industry. Significant influence their way of storing and technological production mode.
It was also established that the activity of proteolytic enzymes and the content of the reduced form of glutathione in yeast alcohol plants are increased (Table 2). Therefore, they are worse preserved and lower the gas-holding capacity of the test. To increase the maltase activity of the pressed yeast produced by distilleries, a method has been developed that a maltose-containing product is introduced into the yeast suspension and aerated for a certain time. The yeast cells are adapted to ferment maltose. The compressed yeast thus processed has a maltase activity of 120-140 min,
which corresponds, according to the classification given in tab.1, yeast maltoznoynoy satisfactory for activity.
Оsmochuvstvitelnost compressed yeast
When evaluating the properties of compressed yeast, their osmosis sensitivity should be taken into account, since when the content of sugar or salt increases in the medium, which increases the osmotic pressure of the solution, the life activity of osmotic-sensitive yeasts is suppressed, the yeast reproduces more slowly, their fermentation energy decreases.
The sensitivity of yeast in bakery production is very important, as in the production of a number of products, a large amount of sugar is added to the dough, increasing the osmotic pressure in the liquid phase of the dough, and also salt, which at the same dosage increases the osmotic pressure 6 times the sugar. Interest in this matter is growing in connection with the currently used in some plants method of phasic dosing of salt in yeast, spoons and dough.
It is believed that the osmosensitivity of yeast depends on the degree of suppression of the functions of cell enzymes with an increase in osmotic pressure. This is evidenced by the fact that the higher the osmosensitivity of yeast, the faster it breaks down during storage. However, not all enzymes in this case react to the same extent. D. White points out that the effect of sodium chloride on yeast maltase is greater than on the zymase complex, that fermenting yeast is more sensitive than respiratory yeast.
Comparing the data on the lifting force and the osmotic sensitivity of commercial compressed yeast,
Figure: 2. Change in lifting force (1 - dough without salt, 2 - dough with salt) and osmosensitivity (5) of compressed yeast during storage at 25 ° C () and 8 ° C ().
to the conclusion that yeasts with a poor lifting force, as a rule, have greater osmotic sensitivity.
The author, together with NI Berzina, experimentally tested the dependence of the osmotic sensitivity of the pressed yeast on their lifting force [158]. Lifting power was expressed in the time (in minutes) during which 50 g salt-free test containing 0,6 g yeast, 20 ml C02 was isolated, and osmosis-sensitivity as the difference between this determination and the lifting force of the same test containing 3,35% salt.
The results obtained in Fig. 2, showed that when stored, the yeast was all the more sensitive to an increase in the osmotic pressure of the medium, the weaker the lift was.
A parallel determination on the rise of the dough in the mold also showed that as the yeast lift increased, their osmotic sensitivity increased.
Therefore, in order for baker's yeast to have low osmosis sensitivity, yeast plants should, along with selecting the appropriate yeast races and applying the optimal process production and storage regime, produce them with the best possible lifting power, not limited to the limits of the standard.
The question of the effect of table salt on compressed yeast is of interest in regard to the behavior of yeast in production and the possibility of storing them in a salt solution in the absence of cold.
The available data on the effect of salt on the vital activity of yeast cells are contradictory. LI Rubenchik and MV Halperin point out that at a concentration of 0,5% salt in malt wort it is impossible to accurately establish the stimulating effect of salt, and at 1 and 2% salt definitely inhibits the multiplication of yeast cells. The addition of 0,5% salt to a dough with a moisture content of 60% favors the growth of yeast during the first 2 hours of fermentation, and later salt has a depressing effect.
KA Kirova observed that the concentration of the salt from 0,5 to 1% favorably favored the growth of yeast cells in the flour mash, and at 2% and higher oppressed them. According to GL Seliber, the salt in certain concentrations increases the yeast ferment ability. Schultz, while adding table salt to the dough with 3% of pressed yeast in an amount of 0,1 to 3% to the weight of flour, found that this reduces the amount of carbon dioxide released and the number of yeast cells, regardless of whether salt was added to the yeast or it is set directly into the dough. Only at the expense of 5-6% yeast by flour weight fermentation intensity decreases only at the beginning, and the results of 3-4-hour fermentation are the same as usual [252]. D. White also indicates that even osmophilic yeast is inhibited by salt.
On the effect of table salt on pressed baker's yeast, we were judged by the fermenting activity of yeast (Figure 3), determined by the weight loss of the roaming mass as a result of the release of carbon dioxide during fermentation [18]. The content of solids in the nutrient medium was about 7%, and the amount of compressed yeast in grams was 1% of the volume of the culture medium in milliliters.
When fermenting malt wort with an increase in the salt concentration in the medium, yeast fermentation energy decreased. With increasing salt concentration in the medium from flour sugared tea leaves, yeast fermentation energy decreased to a greater extent than in malt wort. Under the same conditions, it was lower in brewing than in malt wort.
The method of storage of compressed yeast in a solution of salt in the form of plazmolizirovannom was proposed GL Seliber and RS Katznelson, who believed that the storage
Figure: 3. Fermentation energy of yeast in malt wort () and flour brew () with salt content: 1 ~ 0%; 2 - 1%; 3 - 2%; 4 - 3%; 5 - 4%. yeast 25% -s' solution of a salt of the lift for one to two weeks is reduced slightly.
Checking this method, M. Ya. Kalyuzhny established that when stored in a solution of salt, yeast lose part of the cell water and nitrogenous substances. After storage, even in 6 and 12% salt solutions, they multiply and wander more slowly.
VD Roshchina found that amine nitrogen, nucleic acids and phosphorus compounds are extracted with water lost by yeast cells during plasmolysis with salt. The lost liquid stimulates the multiplication of yeast, but does not cause or activate fermentation. Salt inhibits the autolysis process, but does not reduce it at all, so the fermentation energy decreases over time, but the yeast retains the ability to ferment for 6 months. She recommended a method of preserving yeast with dry salt in the ratio of salt to yeast 1: 5 for storing them for a month at room temperature.
According to EA Gladkova, compressed yeast can be stored only up to 7 days in an 5% salt solution. After their activation in flour floury for 2-3 h on such yeast, bread of normal quality is obtained.
Change in yeast fermentation energy when they are pre-conditioned in salt solution with salt concentration 0; 1,7; 3,4; 5,1 and 6,8% we tested by adding malt wort or a solution of flour brew to them to the salt concentration specified in Table. 3. Comparison of the data obtained with the data in Fig. 3 shows that pre-aging of the yeast in saline solution leads to a decrease in their fermentation activity. The increase in the concentration of salt during fermentation affects negatively and, to a greater extent, in nutrient medium from flour brewing.
3 Table. Losses during the fermentation of saline environments, г
alcohol plants (Table. 2), wherein at zimaznoy activity (determined in the same manner as maltasie, but with the use of glucose), they are not inferior to the yeast, produced by yeast factories.
The intensity of the test recovery in three yeast samples had the same lift as standard. The intensity of the recovery test within the first two hours in yeast, developed yeast and alcohol plants, is almost the same, but further fermentation yeasts distilleries slows. Thus, a legitimate relationship between the lift of yeast standard and maltasie no activity.
Maltasie yeast activity due to the properties of pure cultures used in alcohol production, maltasie their activity and the ability to adapt to maltose. However, the selection of them, unfortunately
uchitytyvayutsya no requirements for compressed yeast baking industry. Significant influence their way of storing and technological production mode.
It was also established that the activity of proteolytic enzymes and the content of the reduced form of glutathione in yeast alcohol plants are increased (Table 2). Therefore, they are worse preserved and lower the gas-holding capacity of the test. To increase the maltase activity of the pressed yeast produced by distilleries, a method has been developed that a maltose-containing product is introduced into the yeast suspension and aerated for a certain time. The yeast cells are adapted to ferment maltose. The compressed yeast thus processed has a maltase activity of 120-140 min,
which corresponds, according to the classification given in tab.1, yeast maltoznoynoy satisfactory for activity.
Оsmochuvstvitelnost compressed yeast
When evaluating the properties of compressed yeast, their osmosis sensitivity should be taken into account, since when the content of sugar or salt increases in the medium, which increases the osmotic pressure of the solution, the life activity of osmotic-sensitive yeasts is suppressed, the yeast reproduces more slowly, their fermentation energy decreases.
The sensitivity of yeast in bakery production is very important, as in the production of a number of products, a large amount of sugar is added to the dough, increasing the osmotic pressure in the liquid phase of the dough, and also salt, which at the same dosage increases the osmotic pressure 6 times the sugar. Interest in this matter is growing in connection with the currently used in some plants method of phasic dosing of salt in yeast, spoons and dough.
It is believed that the osmosensitivity of yeast depends on the degree of suppression of the functions of cell enzymes with an increase in osmotic pressure. This is evidenced by the fact that the higher the osmosensitivity of yeast, the faster it breaks down during storage. However, not all enzymes in this case react to the same extent. D. White points out that the effect of sodium chloride on yeast maltase is greater than on the zymase complex, that fermenting yeast is more sensitive than respiratory yeast.
Comparing the data on the lifting force and the osmotic sensitivity of commercial compressed yeast,
Figure: 2. Change in lifting force (1 - dough without salt, 2 - dough with salt) and osmosensitivity (5) of compressed yeast during storage at 25 ° C () and 8 ° C ().to the conclusion that yeasts with a poor lifting force, as a rule, have greater osmotic sensitivity.
The author, together with NI Berzina, experimentally tested the dependence of the osmotic sensitivity of the pressed yeast on their lifting force [158]. Lifting power was expressed in the time (in minutes) during which 50 g salt-free test containing 0,6 g yeast, 20 ml C02 was isolated, and osmosis-sensitivity as the difference between this determination and the lifting force of the same test containing 3,35% salt.
The results obtained in Fig. 2, showed that when stored, the yeast was all the more sensitive to an increase in the osmotic pressure of the medium, the weaker the lift was.
A parallel determination on the rise of the dough in the mold also showed that as the yeast lift increased, their osmotic sensitivity increased.
Therefore, in order for baker's yeast to have low osmosis sensitivity, yeast plants should, along with selecting the appropriate yeast races and applying the optimal process production and storage regime, produce them with the best possible lifting power, not limited to the limits of the standard.
The question of the effect of table salt on compressed yeast is of interest in regard to the behavior of yeast in production and the possibility of storing them in a salt solution in the absence of cold.
The available data on the effect of salt on the vital activity of yeast cells are contradictory. LI Rubenchik and MV Halperin point out that at a concentration of 0,5% salt in malt wort it is impossible to accurately establish the stimulating effect of salt, and at 1 and 2% salt definitely inhibits the multiplication of yeast cells. The addition of 0,5% salt to a dough with a moisture content of 60% favors the growth of yeast during the first 2 hours of fermentation, and later salt has a depressing effect.
KA Kirova observed that the concentration of the salt from 0,5 to 1% favorably favored the growth of yeast cells in the flour mash, and at 2% and higher oppressed them. According to GL Seliber, the salt in certain concentrations increases the yeast ferment ability. Schultz, while adding table salt to the dough with 3% of pressed yeast in an amount of 0,1 to 3% to the weight of flour, found that this reduces the amount of carbon dioxide released and the number of yeast cells, regardless of whether salt was added to the yeast or it is set directly into the dough. Only at the expense of 5-6% yeast by flour weight fermentation intensity decreases only at the beginning, and the results of 3-4-hour fermentation are the same as usual [252]. D. White also indicates that even osmophilic yeast is inhibited by salt.
On the effect of table salt on pressed baker's yeast, we were judged by the fermenting activity of yeast (Figure 3), determined by the weight loss of the roaming mass as a result of the release of carbon dioxide during fermentation [18]. The content of solids in the nutrient medium was about 7%, and the amount of compressed yeast in grams was 1% of the volume of the culture medium in milliliters.
When fermenting malt wort with an increase in the salt concentration in the medium, yeast fermentation energy decreased. With increasing salt concentration in the medium from flour sugared tea leaves, yeast fermentation energy decreased to a greater extent than in malt wort. Under the same conditions, it was lower in brewing than in malt wort.
The method of storage of compressed yeast in a solution of salt in the form of plazmolizirovannom was proposed GL Seliber and RS Katznelson, who believed that the storage
Figure: 3. Fermentation energy of yeast in malt wort () and flour brew () with salt content: 1 ~ 0%; 2 - 1%; 3 - 2%; 4 - 3%; 5 - 4%. yeast 25% -s' solution of a salt of the lift for one to two weeks is reduced slightly.Checking this method, M. Ya. Kalyuzhny established that when stored in a solution of salt, yeast lose part of the cell water and nitrogenous substances. After storage, even in 6 and 12% salt solutions, they multiply and wander more slowly.
VD Roshchina found that amine nitrogen, nucleic acids and phosphorus compounds are extracted with water lost by yeast cells during plasmolysis with salt. The lost liquid stimulates the multiplication of yeast, but does not cause or activate fermentation. Salt inhibits the autolysis process, but does not reduce it at all, so the fermentation energy decreases over time, but the yeast retains the ability to ferment for 6 months. She recommended a method of preserving yeast with dry salt in the ratio of salt to yeast 1: 5 for storing them for a month at room temperature.
According to EA Gladkova, compressed yeast can be stored only up to 7 days in an 5% salt solution. After their activation in flour floury for 2-3 h on such yeast, bread of normal quality is obtained.
Change in yeast fermentation energy when they are pre-conditioned in salt solution with salt concentration 0; 1,7; 3,4; 5,1 and 6,8% we tested by adding malt wort or a solution of flour brew to them to the salt concentration specified in Table. 3. Comparison of the data obtained with the data in Fig. 3 shows that pre-aging of the yeast in saline solution leads to a decrease in their fermentation activity. The increase in the concentration of salt during fermentation affects negatively and, to a greater extent, in nutrient medium from flour brewing.
3 Table. Losses during the fermentation of saline environments, г
| Duration of fermentation, h | salt concentration medium before fermentation,% | ||||
| 0 | 1 | 2 | 3 | 4 | |
| Solodovoe wort | |||||
| 4 | 0,37 | 0,33 1 | 0,31 In | - 0,30. | 0,28 |
| 24 | 1 3,87 | 3,82 1 | 3,90 1 | 3,86 | 3,72 |
| Muchnaya osaharennya welding | |||||
| 4 | 0,10 | 0,07 | 0,01 | 0,01 | 0,01 |
| 8 | 0,45 | 0,10 | 0,07 | 0,05 | 0,02 |
| 24 | 1,65 | 0,89 | 0,58 | 0,36 | 0,06 |
We also tested the effect of salt at different times of storage of compressed yeast in saline solution due to their ability to lift dough in molds by the method established by the standard. After the first lift of the test, characterizing the lifting power of the yeast in minutes, the dough in the mold was interrupted for 2 min by hand and again noticed the time of raising the test to the crossbar. Similarly, the second and third interruptions were made, after which the total duration of fermentation was established. Then they baked bread from it in a laboratory oven.
4 Table. The quality of the yeast and aged in a piece of saline at 25 ° C
4 Table. The quality of the yeast and aged in a piece of saline at 25 ° C
| Continue a citizen preservation of the tion, day |
Keeping yeast | |||||
| in the piece | in 10% -s' solution salt |
in 25% strength solution salt |
||||
| Climbtion force | Длитель nost of bro tion |
Climbtion force | Длитель nost of bro tion |
Climb tion force |
Длитель fermentation |
|
| min | ||||||
| 3 | 71 | 260 | 83 | 283 | 99 | 285 |
| 7 | 105 | 315 | 87 | 342 | 121 | 318 |
| 11 | — | — | 152 | 397 | 189 | 440 |
| 15 | — | — | 303 | 569 | 280 | 530 |
It is established (Table 4) that the lifting power of the yeast stored at 25 ° C for 7 days in a piece in an 25% salt solution is outside the standard, and the yeast stored in the 10% salt solution still retains standard lifting force. On the eleventh day, the yeast stored in the piece becomes unsuitable for use, and the salts stored in the solutions do not lose vitality, have no signs of spoilage, and give the bread a normal quality, although their lifting power considerably exceeds the standard. This shows the possibility of a short-term storage of yeast in a salt solution with a concentration of 10%.
Activation of compressed yeast
In order to reduce the consumption of yeast or reduce the duration of fermentation at the same expense, the USSR developed an effective method for activating compressed yeast.The intensity of fermentation of compressed yeast in the test at the beginning of fermentation is very low and only gradually increases. This can not be explained by the small initial content of yeast cells. In the spoon and dough with pressed yeast, so many cells are introduced, that they even multiply to a small extent even during the entire fermentation period.
This is explained by the fact that squeezed yeast cells are grown in a yeast plant in a very dilute nutrient medium with a strong blowing of air. Therefore, they assimilate sugar mainly on the process of breathing, multiply intensively and fermentation almost does not cause.
Yeast in such conditions are obtained respiratory type, adapted to existence under aerobic conditions, i.e. with sufficient access to oxygen. They differ in the low content of glycogen, propensity to accumulate fat and have a high ability for oxidative processes. The ability to restore processes and fermentation in them is lowered, so assimilable sugar they are mainly oxidized to carbon dioxide and water.
In the test, the consistency is thick, so air access to yeast cells is difficult and they are almost in anaerobic conditions. To get the energy necessary for their life, they are forced to resort to fermenting sugar. With this switching of yeast from the respiratory to the fermentative type of vital activity, the internal structure changes and the whole organism of the yeast cell is reconstructed, which adapts itself to the new conditions of existence in the test. In them, the content of glycogen increases, the oxygen consumption for breathing decreases. They are more active in starting to make recovery reactions, turning sugar into alcohol and carbon dioxide. This requires the restructuring of the entire enzyme complex of the yeast cell to catalyze the fermentation process.
It is also important that the yeast cells are grown at a yeast plant in a treacle wort containing sucrose and significantly different in composition from the flour medium in which maltose is mainly found. Therefore, in the dough or test yeast cells for a while get used to and adapt to new conditions.
In addition, in pressed yeast, the cells are at rest for a long time, in a state of complete absence of nutrients, and when they enter the nutrient medium, they gradually move to vigorous activity. This requires a certain amount of time, called the lag phase of microorganisms. Due to the above reasons, in the initial period of dough preparation, the fermentation process is not intensive.
AG Ginzburg [39] developed a method for activating compressed yeast, which consists in the fact that the period of rearrangement of yeast organisms from the respiratory to the fermentation type is carried out before they are added to the dough in a specially prepared nutrient medium. The latter consists of the welding of a small amount of processed flour enriched with white barley malt and soy flour, which are rich in enzymes and nutrients necessary for yeast: amino acids, vitamins, etc.
Welding is recommended to cook in the ratio of flour and water 1: 3. The consumption of flour for the activation of yeast during the preparation of the dough is 3-5% of its content in the test, of which up to 2% is consumed for the preparation of tea leaves. The consumption of soy flour is 0,5% The use of white malt in the preparation of tea leaves increases the formation of gas at all stages of the preparation of the dough, especially during the proofing. Its consumption should be 0,2-0,4% to the weight of flour in the test.
Yeast is activated at a temperature of 30-35 ° C. A further increase in temperature leads to a deterioration in the quality of the bread. The duration of the activation with the no-boiling method of preparation of the test is desirable within 2-3 h. When preparing the dough by the sponge method, the yeast is activated for 1 h.
Formulation of compressed yeast to activate 100 kg of flour in the dough, depending on the consumption of yeast is as follows:
2 kg of flour brew 4-6 l of hot water (recommended by boiling water) and after cooling to 58-64 ° C, 0,2-0,4 kg of white fermented-active malt *. After thorough mixing, add 4,5-6,5 l of water at a temperature such that the temperature of the mixture is reduced to 35-40 ° C. Then add another 1,3-2 kg of flour, 0,5 kg of soy flour and pressed yeast in an amount of 20-30% less than that specified in recipe for 100 kg flour. After stirring, the mixture must have a temperature of 30-32 ° C. Activation lasts for 1 hours. The increase in this period
up to 2-3 h does not impair the quality of yeast and bread. The lifting power of the activated pressed yeast by the "ball" method is equal to 8-9 min, humidity 75-78%, acidity 3,5-4,5 ° N.
Dough on activated yeast is prepared in the usual way, but consider the amount of flour and water that went to activate the yeast. Activation can be done without malt or soy flour, but the effect is somewhat less. When using activated compressed yeast, their consumption is reduced by 25-30% while reducing the duration of fermentation of the sponge by 10-15%. An even greater effect results from the use of activated pressed yeast in the preparation of an unpaired test. Activation gives a greater effect, the lower the yeast consumption per 100 kg of processed flour and the weaker the yeast lift.
Studies have shown that at the time of activation yeast cells do not multiply, and the loss of solids during the preparation of the dough with preactivation of compressed yeast is reduced by reducing the duration of fermentation. Activation of the pressed yeast also leads to an improvement in the quality of the bread and an increase in its volume. When using activated yeast, the products acquire a more intense color of the crust due to brewing about 2% of the whole flour.
In bakeries, for several years of work with the activation of compressed yeast, they saved from 25 to 40% of compressed yeast. At the same time, the quality indicators of products improved.
For activation, it is convenient to use special installations of the UAD brand, designed for plants of different capacities. The installation is equipped with a vat with a stirrer, which is used to prepare the infusion of flour, prepare the nutrient medium and mix it with compressed yeast to be activated. There is an automatic meter and a water tank above the vat with a stirrer. There is a reservoir underneath that serves to maintain a mixture of yeast with a nutrient medium. The tank is divided into two parts, and when the mass for activation is held in one half, the already activated Yeast from the second half of the vat is supplied to production.
In some enterprises use more simple ways to activate the compressed yeast in brewing or saccharified flour mash.
When yeast is activated on saccharified tea leaves, the flour is brewed with hot water according to the recipe indicated in Table. 5. At 63-65 ° C, add flour to flour 1 (preferably malt or flour from sprouted grain) and leave it for saccharification for 15-20 min. Then, the tea leaves are diluted with cold water, and its temperature should be lowered to 30-32 ° C. The preparation of the pressed yeast and the duration of activation are the same as indicated above.
5 Table. Formulation kg, and the activation of yeast in the saccharified welding mode flour
| The formulation and mode | Welding Preparation | Brewing Sugar | Dilution
brewing |
Activation
yeast |
| Wheat flour
Hot water: |
19 | 1 | — | — |
| in summer | 48 | — | — | — |
| in winter | 60 | — | — | — |
| The water is cold: | ||||
| in summer | — | — | 32 | — |
| in winter | — | — | 20 | — |
| welding | — | 67-79 | 68-80 | — |
| Diluted tea leaves .... | — | — | — | 100 |
| Pressed yeast. . . | — | — | — | 5 |
| Temperature, ° C. . . | 63-65 | 60-63 | 30-32 | 28-30 |
When yeast is activated on a flour mill, 20 kg of processed flour is mixed with 30 l of water, which is set in two or three portions. With the last portion of water, 1 kg of pressed yeast diluted in water is added. The duration of activation is for wheat flour: wallpaper - 1,5 — 2; Grades II - 2 — 2,5 and grades I — 2,5 — 3 hours. For any activation method, yeast must have a lifting force according to the “ball” ascent method 10 — 15 min, and the acidity for flour grade I is 2,5 — 3, grades II - ' 3 — 4, wallpaper - 4,5 — 5 ° N. When preparing a dough for dough, the yeast activated by these methods is consumed in the amounts indicated in the table. 6. When preparing dough from wallpaper flour, in addition to activated yeast, 10 — 15% ripe dough is added to the dough.
Flow activated yeast,% by weight of flour in the dough
Flow activated yeast,% by weight of flour in the dough
| Variety of wheat flour | Yeast activated | |
| muçnoy swill | of welding osaharennoy | |
| I | 25 | 8-10 |
| II | 12-15 | 7- 8 |
| wholemeal | 10 | 4- 5 |
EA Isakova and GI Fertman [66] proposed to use, when activating compressed yeast, instead of malt, aqueous extracts from rye malt sprouts that contain a large amount of nitrogenous substances assimilated by yeast, vitamins and growth substances.
To reduce foaming during activation of compressed yeast, the method of adding to the wandering mass from 1 to 3% to its volume of a salt solution of density 1,19 kg / l was used, which is 0,06% to the weight of the flour in the dough. The lifting force is almost unchanged, and the filling time of the dosing tanks is reduced by two to three times [81].
Yeast is activated according to the following recipe: tea leaves - 170 l, water - 230 l, flour - 50 kg, pressed yeast - 18-28 kg, salt solution - 10 l. The moisture content of the mixture is 85 - 86%.
Activation of compressed yeast contributes to a significant improvement in the quality of finished products also in the development of high-value products. Thus, in the production of buns of increased caloric content by conventional technology, their quality was low, and the fermentation duration of the test increased to 3-4 h. To improve the quality, a double norm of compressed yeast was used.
L.D. Tomashevskaya and A.N. Kharina [207] developed a non-polluted way of preparing the test for activated yeast, due to which the yeast consumption does not exceed the norm; The fermentation time is shortened, and the quality of the products is significantly improved.
The essence of the method is that compressed yeast, milk, fat, eggs and 4/5 of all sugar come from the entire recipe to the activation phase. The mixture is left to ferment for 8-10 hours at 32-35 ° C until the acidity is 8 ° N. The lifting force should be 25-35 minutes. During fermentation, the mass is stirred once or twice. When kneading the dough, add all the rest of the raw materials. The duration of fermentation of the dough is only 1,5-2 hours at 28-30 ° C with one stirring after 50-60 minutes of fermentation.
ДTHER way to improve the fermentation activity of compressed yeast
In addition to the described biochemical method of activating compressed yeast, other methods have been found that increase the intensity of fermentation of sugars by yeast. These include the treatment of a suspension of compressed yeast in a hydrodynamic vibrator and a high-speed rotary kneading machine.
AG Beschastnov and co-workers [21] found that processing an aqueous suspension of compressed yeast for 5 min in an acoustical field of sound and supersonic frequency using a hydrodynamic vibrator used to prepare a fat emulsion (see page 73) enhances their ability ferment sugars, especially maltose.
This is explained by the disconnection of yeast cells, thereby increasing their contact with the nutrient medium, as well as the activation of the physiological activity of yeast cells. The last conclusion is made as a result of the fact that processed yeast on wort agar germinated through 12-15 h, and untreated - only through 20-24 h.
The dough produced on the so treated yeast was loosened, softer and weaker, the proofing was shortened, and the baked bread was more porous, had a large volume, and the bread had a higher ratio of height to diameter.
Such processing of the yeast suspension is easily feasible, since many enterprises have hydrodynamic plants. Therefore, this method of yeast activation must be tested in production conditions.
When the author together with AI Skorikova [187] worked continuously with a speedy rotary kneading kneader (see page 232), it was found that when passing through the slurries of compressed yeast, the fermentation activity in flour flour with the intensification of machining was also significantly increased (Figure 4). At 2800 rpm, the gas formation machine increased over 2 h by 69%, and for 3 h - by 27%
Figure: 4. Gas formation of yeast V at different numbers of machine revolutions per minute: 1 - 2800; 2 - 1400; 3 - 400; 4 - 0 (control). (Solid lines).
Similar results were obtained with dry yeast, but the effect of stirring affected their activity to a lesser extent: the formation of gas increased in 2 h by 35%, and for 3 h - by 24% (dashed lines).
In experiments with liquid yeast, the activity increased insignificantly: the increase in gas emission was 2-3 h in total 6%. The same was observed with multiple yeast passing through the machine at 400 rpm.
It should be taken into account that pressed, and in particular dry yeast are in suspension in the aggregated state in the form of conglomerates consisting of a multitude of cells. Therefore, the increase in fermentation activity is possible due to the disaggregation of these grains and the release of yeast cells.
This is confirmed by the fact that dry yeasts are less activated with the same mechanical treatment, since they give more stable particles in the suspension, and liquid yeast, in which the yeast cells are in a single, suspended state, are practically not activated with increased agitation.
For the same reason, there is no reason to believe that the mechanical treatment of the yeast of the suspension before fermentation improves the yeast fermentation activity due to changes in their physiological state.
The calculation of the number of colonies grown on sowing on the agarized wort of the treated suspension (Table 7) showed that when the mechanical processing of the suspension is increased, the total number of colonies and the relative content of small ones increase. This indicates the grinding of the particles of the suspension and the increase in their number.
Table. Sprouting yeast colonies
To reduce foaming during activation of compressed yeast, the method of adding to the wandering mass from 1 to 3% to its volume of a salt solution of density 1,19 kg / l was used, which is 0,06% to the weight of the flour in the dough. The lifting force is almost unchanged, and the filling time of the dosing tanks is reduced by two to three times [81].
Yeast is activated according to the following recipe: tea leaves - 170 l, water - 230 l, flour - 50 kg, pressed yeast - 18-28 kg, salt solution - 10 l. The moisture content of the mixture is 85 - 86%.
Activation of compressed yeast contributes to a significant improvement in the quality of finished products also in the development of high-value products. Thus, in the production of buns of increased caloric content by conventional technology, their quality was low, and the fermentation duration of the test increased to 3-4 h. To improve the quality, a double norm of compressed yeast was used.
L.D. Tomashevskaya and A.N. Kharina [207] developed a non-polluted way of preparing the test for activated yeast, due to which the yeast consumption does not exceed the norm; The fermentation time is shortened, and the quality of the products is significantly improved.
The essence of the method is that compressed yeast, milk, fat, eggs and 4/5 of all sugar come from the entire recipe to the activation phase. The mixture is left to ferment for 8-10 hours at 32-35 ° C until the acidity is 8 ° N. The lifting force should be 25-35 minutes. During fermentation, the mass is stirred once or twice. When kneading the dough, add all the rest of the raw materials. The duration of fermentation of the dough is only 1,5-2 hours at 28-30 ° C with one stirring after 50-60 minutes of fermentation.
ДTHER way to improve the fermentation activity of compressed yeast
In addition to the described biochemical method of activating compressed yeast, other methods have been found that increase the intensity of fermentation of sugars by yeast. These include the treatment of a suspension of compressed yeast in a hydrodynamic vibrator and a high-speed rotary kneading machine.
AG Beschastnov and co-workers [21] found that processing an aqueous suspension of compressed yeast for 5 min in an acoustical field of sound and supersonic frequency using a hydrodynamic vibrator used to prepare a fat emulsion (see page 73) enhances their ability ferment sugars, especially maltose.
This is explained by the disconnection of yeast cells, thereby increasing their contact with the nutrient medium, as well as the activation of the physiological activity of yeast cells. The last conclusion is made as a result of the fact that processed yeast on wort agar germinated through 12-15 h, and untreated - only through 20-24 h.
The dough produced on the so treated yeast was loosened, softer and weaker, the proofing was shortened, and the baked bread was more porous, had a large volume, and the bread had a higher ratio of height to diameter.
Such processing of the yeast suspension is easily feasible, since many enterprises have hydrodynamic plants. Therefore, this method of yeast activation must be tested in production conditions.
When the author together with AI Skorikova [187] worked continuously with a speedy rotary kneading kneader (see page 232), it was found that when passing through the slurries of compressed yeast, the fermentation activity in flour flour with the intensification of machining was also significantly increased (Figure 4). At 2800 rpm, the gas formation machine increased over 2 h by 69%, and for 3 h - by 27%
Figure: 4. Gas formation of yeast V at different numbers of machine revolutions per minute: 1 - 2800; 2 - 1400; 3 - 400; 4 - 0 (control). (Solid lines).Similar results were obtained with dry yeast, but the effect of stirring affected their activity to a lesser extent: the formation of gas increased in 2 h by 35%, and for 3 h - by 24% (dashed lines).
In experiments with liquid yeast, the activity increased insignificantly: the increase in gas emission was 2-3 h in total 6%. The same was observed with multiple yeast passing through the machine at 400 rpm.
It should be taken into account that pressed, and in particular dry yeast are in suspension in the aggregated state in the form of conglomerates consisting of a multitude of cells. Therefore, the increase in fermentation activity is possible due to the disaggregation of these grains and the release of yeast cells.
This is confirmed by the fact that dry yeasts are less activated with the same mechanical treatment, since they give more stable particles in the suspension, and liquid yeast, in which the yeast cells are in a single, suspended state, are practically not activated with increased agitation.
For the same reason, there is no reason to believe that the mechanical treatment of the yeast of the suspension before fermentation improves the yeast fermentation activity due to changes in their physiological state.
The calculation of the number of colonies grown on sowing on the agarized wort of the treated suspension (Table 7) showed that when the mechanical processing of the suspension is increased, the total number of colonies and the relative content of small ones increase. This indicates the grinding of the particles of the suspension and the increase in their number.
Table. Sprouting yeast colonies
| pressed yeast | Number of yeast colonies | The relative content of small colonies. % | |
| common | including small | ||
| control | 87 | 22 | 25 |
| Missed by car | |||
| in particular, / min: | |||
| 400 | 90 | 23 | 26 |
| 1400 | 107 | 35 | 32 |
| 2800 | 125 | 53 | 42 |
Thus, the yeast fermentation activity with intensive mixing of their suspensions is enhanced by the disaggregation of the yeast conglomerates in the suspension, thereby increasing the contact surface with the substrate. Therefore, dry yeast, the particles of which are stronger, are less activated than compressed, and the liquid, the cells of which are separated, do not react to intense mechanical stirring.
Regulation of consumption of compressed yeast
Workers of factories have repeatedly pointed out that when dosing the pressed yeast, it is necessary to be guided not only by the approved formulations, but also by the lifting power of the yeast.
In the formulations of bakery products do not really take into account the quality of yeast, the methods of preparing the dough and the presence in the formulation of components, the presence of which in large quantities inhibits the vital activity of yeast cells.
Group of bakery products from wheat flour to normalize the flow of compressed yeast
| number | Products | Bookmark% by weight of flour | Consumption of yeast lift 60-70 minutes% by weight of flour | ||
| Group | grade flour | sahara | fat | EGGS | |
| 1 | Bread and bakery products from flour I and higher grades | ) One | ) One | 1 30 | 4,0 |
| 2 | Also | More \ 15 | More> 10 | Over / 10 | 3,0 |
| 3 | »» | ) One | 1 15 | Until 10 | 2,5 |
| 4 | »» | 16-20 | 11-15 | (250 pieces per 100 kg of flour) | 2,0 |
| 5 | »» | 7-15 | 5-10 | — | 1,5 |
| 6 | »» | 6 | Until 4 | — | 1,2 |
| 7 | »» | 3 | 1,0 | ||
| 8 | Same from II grade flour | 0,7 | |||
| 9 | Bread made from wholemeal | — | — | 0,5 | |
Fig. 5. Consumption of compressed yeast at different lifting forces.
A. Zavyalov [59] on the basis of the conducted studies suggests to reconsider the existing order of rationing of compressed yeast consumption taking into account the presence of additives in the recipe. For this, it is proposed to divide the assortment of products into 9 main groups, indicated in Table. 8, and set the same rate of consumption of pressed
yeast with their lifting force 65-70 min. In the presence of yeast of worse quality, their consumption can be determined by means of a graph (Fig. 5).
A. Zavyalov [59] on the basis of the conducted studies suggests to reconsider the existing order of rationing of compressed yeast consumption taking into account the presence of additives in the recipe. For this, it is proposed to divide the assortment of products into 9 main groups, indicated in Table. 8, and set the same rate of consumption of pressed
yeast with their lifting force 65-70 min. In the presence of yeast of worse quality, their consumption can be determined by means of a graph (Fig. 5).
Fig. 5. Consumption of pressed yeast at different lifting capacity.The found consumption of yeast involves preparing the dough by a sponge method on some pressed yeast. To take into account differences in the technology of preparation of the test, it is suggested to multiply the found value by the following factors: with a free-choice method for preparing the test for 2,0-2,5; with the preliminary activation of compressed yeast for another 0,6-0,7; when adding liquid yeast or starter cultures to the pressed yeast for another 0,7-0,8.
This proposal deserves discussion by industry workers.
The use of liquid instead of compressed yeast yeast concentrate
Despite a significant increase in the production of compressed yeast, the issue of saving their consumption is very urgent.
To save yeast, N. Ye. Morev and I. A. Meltser proposed in cities with yeast factories to transport yeast milk, previously concentrated to a content of 500 g of conditional compressed yeast per liter. The separated concentrate is cooled down to 5 ° C and transported to bakeries in milk-type tanks. This reduces the consumption of yeast by 10-11% per pressed.
At the Tartu Bakery, yeast milk, obtained from a yeast plant, which contains 15% of dry matter, is used instead of compressed yeast. Its lifting power is much better than that of pressed yeast, thereby accelerating the fermentation of the dough. The quality of products has improved.
The economy of yeast is 12-14%, counting on pressed. The annual savings for the plant with an output of 40 tons of bread per day is about 2000 rub. Yeast concentrate is also used by bread-baking plants in Minsk. Savings at the yeast plant is 5000 rub. per year, except for the savings available at bakeries.
Dried yeast, even with their normal quality, is consumed in an amount that is 1,5-2 times the consumption of compressed yeast, counting for dry matter. However, even with such a large expense, the dough proving is delayed and the products are vague, low, not sufficiently loosened. Before using dry yeast to loosen the dough, it is necessary to activate them. 1 kg of yeast is soaked for 50 min in a six-fold amount of water at 30 ° C, periodically mixing. To the soaked yeast, add 15 kg of flour sweet brew, pre-diluted 9 l of cold water. The whole mixture must have a temperature of 27-30 ° C. Fermentation lasts for 6 h. The tea leaves are prepared from wheat flour II grade with the ratio of flour to water 1: 3. First, pour 3 / 4 all the flour with boiling water (or warm water followed by steam heating to 75-80 ° C), and after cooling to 63 ° C add the rest of the 1 / 4 portion of the flour and leave for saccharification at 2 h.
The dry yeast thus activated has a lifting force according to the "ball" method 8-14 min, acidity 4-5 ° H. To avoid acidity increase, they must be consumed during 4 h, and when cooled to 15-17 ° C - within 24 hours . The consumption of good dry yeast is, depending on the grade of products 0,3-0,7% by weight of the processed flour.
The mode of preparation of the test with the use of activated dry yeast does not change, but the amount of flour and water contained in them should be taken into account. The acidity of the test is increased in comparison with the use of compressed yeast at 0,5-1 ° N.
When yeast is activated, strong foaming is observed. To reduce it, it is recommended to replace the 1 / 4 portion of the wheat flour with rye-seed meal when preparing the tea leaves. Before selecting from the vats, the yeast must be mixed so that they do not settle.
The following way of activation of yeast during processing of wheat flour is also used. Instead of 1 kg of compressed yeast, take 300 g dry, mix them with 3,6 l water temperature of 30 ° C and stand 30 min at the same temperature. Then add 1,8 kg
wheat flour II grade and put in a thermostat at 30 ° C for 2 h. These sprouts are prepared with an odor. The fermentation time can be longer than usual. If the quality of dried yeast is poor, it is necessary to give one more food. To do this, add 3,5 l of water and 1,8 kg of wheat flour II grade and set for fermentation at 30 ° C for 1,5-2 h.
I. K. Yeletsky and N. S. Popova [114] recommend, for activation of dry yeast, to soak 12 liters of water 1 kg of yeast at a temperature of 30 ° C for 20 min. Then add 6 kg of wheat flour II grade, mix thoroughly and hold at this temperature 2 h.
Many bakery enterprises activate dried yeast as well as pressed, with the only difference that instead of pressed, prescribe dried, previously soaked for 40-50 mines in 5-6-fold amount of water. Recipe and activation mode, as well as the quality and consumption of activated yeast, remain the same.