RU2612151C1 - Method of producing soy protein isolate - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: for manufacture of a soy protein isolate of white petal the method is performed in the following way. Raw materials with the PDI solubility index - from 55 to 95, when the thickness of the white petal or its waste is from 0.1 to 1.5 mm, water and alkali are fed to obtain a soy protein suspension. Its aqueous alkaline processing is performed in the gravity swirling flow, at that, the raw material, water and alkaline is fed to the stream beginning. Extraction is carried out in two stages at a temperature of 48-65 °C and pH 6.8-8.8. While reducing the solubility index PDI of less than 75 after the second extraction a suspension processing with live steam is carried out at a temperature of 82-102 °C and a pressure of 2.2-4.0 Bar during the time excluding the protein denaturation, and then the temperature is rapidly reduced to 48-65 °C. The extract is separated and the liquid phase premixing with an acid and proteins precipitation at pH, corresponding to the soy protein isoelectric point are carried out. A whey is separated from the precipitated proteins, the precipitated proteins are washed. The liquid phase formed during the proteins isolation are used in the raw materials processing and dissipation. The ready product is dried and packed.

EFFECT: product with high organoleptic indicators, on a uniform product mainly containing high molecular weight proteins, the method allows reducing protein loss.

5 cl, 2 ex

Description

The invention relates to the production of soybean products, in particular to the production of soy protein isolate (SPI), and can be used in the food industry, for the needs of meat processing, baking and confectionery industries, as well as in cosmetology and pharmaceuticals; in the production of children's and sports protein foods, food additives, high-energy drinks, in animal feed.

The need to develop the production of soybean products is mainly due to the lack of animal proteins for humanity. The value of soy is in the high content of a balanced protein with high biological properties, which is perfectly absorbed by the human body. It is rich in amino acids, vitamins, phospholipids and isoflavones - one of the most active components in soybeans. They reduce the risk of developing cardiovascular disease and lower serum cholesterol.

Soy protein is used in sausages to replace expensive myofibrillar muscle protein, to produce emulsions from low-grade meat, to reduce the fat content in the formulation without compromising the organoleptic characteristics of the finished product. High functional and technological properties of an isolated protein in combination with increased biological value and multivariate technological applications make this product very relevant when deciding on the production of products for a healthy lifestyle.

There are many technological processes for producing soy protein isolates. More preferred are technologies that are based on the further processing of the meal obtained after extraction of the oil from the seeds. Most soy isolates entering the market are produced by extraction, precipitation and neutralization, carried out at given pH values, and subsequent spray drying of the resulting product.

In this invention, the authors proposed a method for producing a protein isolate, where the raw material is soy flour or, predominantly, “White Petal” —hexane-free soy petal obtained from food varieties of peeled soy seeds, international abbreviation (WF), with the following indicators :

In the above table, two indicators are important: PDI and lobe thickness, which are the main ones when processing a white lobe into soy protein isolates.

The higher the protein solubility index (PDI - Protein Dissolubility Index), the higher the yield of the costly isolate in the process, and the less the fiber, and vice versa. Unfortunately, this indicator is not always stable due to the heterogeneity of the raw materials supplied for processing, and the yield of isolate is directly proportional to this indicator. The standard requirements for the feedstock in the conventional technologies for processing a white petal into isolated proteins are reduced to the fact that the solubility index PDI should not be lower than 80, and the thickness of the petal should not exceed 1 mm, otherwise soy flour gets into difficultly soluble lumps, which is significantly reduces the final yield of expensive protein.

The proposed method allows you to work with raw materials - white petal or white petal with weeds (small particles of flour) and with low and high solubility of raw materials - the solubility of which PDI is from 55 to 95, with a thickness of flakes from 0.1 microns to 1.5 mm .

One of the main problems of technology for producing soy protein isolates. is the problem of low yield of expensive isolate in the process.

The reason for this arises when preparing raw materials for the extraction process by dissolving a protein-containing substance. The protein-containing substance is ground to flour, then the flour is suspended in an aqueous solution or in water with the addition of alkali. Often an enzyme preparation, such as a protease, is used in this process. However, the need to use high temperature for dissolution and the high pH values used lead to protein damage.

Thus, from DE-1203588, it is known that the process of alkaline extraction in the preparation of protein from a protein-containing substance is facilitated by the preliminary treatment of the aqueous suspension with hydrogen peroxide in the alkaline region and proteolytic enzymes. To do this, first increase the pH of the suspension of the protein-containing substance, then add hydrogen peroxide to the process, and then increase the temperature to initiate peroxidation. The pH value is set to 4-9, and enzymes are added to the suspension, the minimum activity of which is in this pH range. After this, the suspension is stirred for two hours. Plant enzymes such as bromelin, ficin and papain are used. After enzymatic hydrolysis, the protein dissolves due to the fact that the pH is increased to 9-12. High temperatures are used, while it is known that this, combined with a high pH value, leads to protein damage. Repeated changes in the pH value in the case of this known method makes it costly to use it on an industrial scale, and leads to a high consumption of alkali and acid, accompanied by strong salt formation.

The use of proteolytic enzymes to increase the solubility of soy proteins is also known from DE-4429787-C2. In this case, the starting material is extracted first with alcohol, and then crushed! and then enzymatically cleaved with endo- and exoproteases in the pH range from acidic to neutral. Due to the use of alcohol for extraction, this method is expensive and therefore unprofitable. It is necessary to constantly take into account the explosion hazard of the process, as well as to carry out the process of inactivation of the used enzymes due to the available alcohol.

The second reason for the low protein yield in the known processes for its production are very stringent extraction conditions, which lead to large damage to the protein, which leads to its loss. So, during extraction, usually a pH of 9-12 and high temperatures are used, which, as you know, leads to protein denaturation.

Thus, a known method of producing soy protein isolate, in which the protein concentrate is pre-treated with water heated to a temperature of 50 ° C, so that the concentration of solids in the resulting suspension is 12.5%. After that, using a 25% solution of sodium hydroxide set the pH value to 9. The ratio of enzyme / protein is 1: 5500. The suspension is stirred for 15 minutes at a temperature of 45 ° C and subjected to separation in a separator under vacuum. The precipitate is again treated with water, in the resulting suspension, the pH value is adjusted to 11.2 with a 25% sodium hydroxide solution and stirred for 15 minutes. Add proteases with a total activity of 6 Anson units / kg protein, which corresponds to an enzyme / protein ratio of 1: 400. The precipitate is diluted with water, washed and inactivated enzymes, neutralized with a solution of sodium hydroxide and then subjected to spray drying. RF patent 2233097.

In this method, using alkaline extraction using the countercurrent method, the protein is dissolved by temperature gradients, various pH values and the simultaneous action of protein-cleaving enzymes. In some cases, hydrogen peroxide and / or alcohols are used.

In this source, as in all of the above, to create conditions for the isolation of protein from solids before and during extraction, enzymes are used, and stringent extraction conditions are used, which leads to large damage to the protein, a significant decrease in its functional properties (PDI solubility index may fall to 50-55), product heterogeneity and high cost. Such soy isolates are not suitable for food production, they can only be used in cosmetic production.

From the sources described above it is known to supply the supernatant after precipitation of the proteins at the extraction stage to reduce protein loss, however, the preparation of the raw material and its dissolution is carried out either with water or with an alkali solution. Meanwhile, the authors' studies showed that the use of supernatant (whey), consisting of residual dissolved sugars and minerals and a solid phase containing precipitated proteins, at the stage of preparation of the raw material and its dissolution allows to reduce the time of dissolution (soaking), to increase the uniformity of the mixture, reduce the time of the process and increase the yield of protein by increasing its extractability.

Closest to the proposed is a method for producing soy protein isolate from a white petal and / or its waste, including the supply of raw materials, water and alkali to obtain a suspension of soy protein, obtaining a suspension of soy protein by dissolving the raw material in an aqueous alkaline solution, extraction of the resulting suspension, separation extract, acid precipitation of proteins at a pH corresponding to the isoelectric point of soy proteins, separation of serum from precipitated proteins, washing the precipitated proteins, drying and packaging of the finished product. Published application US 20060134310 A1. The known method has all the above disadvantages.

The objective of the present invention is to develop a method for producing soy protein isolate, which allows to reduce protein loss in the main stages of the process and to obtain a homogeneous product containing mainly high molecular weight proteins.

The technical result of the invention is to increase the yield of high molecular weight protein, due to: ensuring high-quality preparation of raw materials; reducing the residence time of raw materials at the extraction stages and providing mild conditions for its implementation; the return and use in the process of virtually all liquids after precipitation and washing of proteins, the use of hot steam with a decrease in the solubility index of raw PDI less than 75; the implementation before the stage of acid deposition pre-mixing the liquid phase with the acid. Moreover, such wastes (weeds) of the white petal (soy flour) can be used as raw materials, the protein cannot be extracted from which in other known cases.

To solve the above technical problem in a method for producing soy protein isolate from a white petal and its waste, including supplying raw materials, water and alkali to obtain a suspension of soy protein, obtaining a suspension of soy protein by dissolving the raw material in an aqueous alkaline solution, extracting the resulting suspension, separating the extract acid deposition of proteins at a pH corresponding to the isoelectric point of soy proteins, separation of serum from precipitated proteins, washing the precipitated proteins, drying and packaging of the finished product using raw materials with a solubility index PDI of 55 to 95, with a white petal or its waste thickness of 0.1 microns to 1.5 mm,

before dissolving the raw material, it is subjected to its aqueous-alkaline treatment in a gravitational swirling flow, while the raw materials, water and alkali are fed to the beginning of the flow,

extraction is carried out in two stages at a temperature (48 ° C-65 ° C) and pH (6.8-8.8),

the liquid phase formed in the process of protein isolation is used in recycling during processing and dissolution of raw materials,

with a decrease in the solubility index PDI of less than 75 after the second extraction, the solid phase is treated with hot steam at a temperature of (82 ° C-102) ° C, pressure (2.2-4.0) Bar for (0.5-2.5) and then sharply lower the temperature to 48 ° C-65 ° C,

prior to the acid deposition step, preliminary mixing of the liquid phase with the acid is carried out.

In this case, it is preferable to add a defoamer when processing raw materials in a swirling gravitational flow, for which it is preferable to use FOAM BLAST 300K.

It is preferable to use (10% -98%) NaOH as alkali.

In this case, the acid precipitation of proteins is preferably carried out with hydrochloric acid.

The applicant also protects the product obtained by the method according to p. 1. The advantages of the proposed method compared to the known ones are as follows:

This invention allows to increase the yield of high molecular weight protein, regardless of the quality of the feedstock (white petal) by 5-7% on a dry matter basis. Ultimately, the yield of soybean isolated high molecular weight protein is 45% on a dry matter basis. At the same time, in the raw materials used, the ratio of white petal / garbage (waste, weed, white petal) can reach a percentage of 70/30 with a stable yield of the finished product. The spectrum of the protein isolated in this method has an average molecular weight of from 10,000 Daltons to 800,000 Daltons. This range suggests that this method is effective when working not only with high-quality raw materials, but also with raw materials, where there is high weed. At the same time, white petal waste can be used as a raw material, the extraction of protein from which in other cases fails.

Water-alkaline processing of raw materials in a gravitational swirl flow before dissolution allows for complete soaking of the raw materials and to obtain raw materials of a uniform shape and the same specific gravity, which is important, because the raw material in this case is fed into the extraction in the form of an absolutely homogeneous mass, with a stable pH value and completely ready for protein extraction. In the end, this allows you to allocate an additional 5-7% of high molecular weight expensive protein.

The second stage of extraction with additional dissolution (soaking) and decantation also makes it possible to isolate, together with the first extraction, an additional amount of protein, while separating insoluble carbohydrates - mainly fiber and residues of water-insoluble proteins.

The liquid phase formed in the process of isolating proteins is fed to the beginning of the technological cycle to dissolve and activate the extractable properties of the white petal fed to the treatment. This allows you to significantly reduce water consumption (by 80%), and at the same time, using the proteins and sugars contained in the liquid phase mixed with an alkaline solution, activate the extracted properties of the raw materials to the maximum.

At a low solubility index (PDI), below 75, which is critical for the full extraction of protein from raw materials, after the second extraction, the suspension is treated with hot steam at a temperature of (82 ° C-102) ° C, pressure (2.2-4, 0) Bar for (0.5-2.5), and then sharply reduce the temperature to 48 ° C-65 ° C. This helps to enhance the effect of extraction of such a protein from a raw material that could not be previously extracted. A sharp decrease in the temperature of the extract due to its direction in a vacuum container allows you to avoid protein denaturation. This allows you to maintain a stable protein yield in the presence of high weed raw materials and low solubility index (PDI).

Before the acid precipitation step, preliminary mixing of the liquid phase with the acid is carried out, for example already in the pipeline. This allows you to reduce the pH of the extract to an isoelectric point already in the stream and in the deposition tank there is no fluctuation in the pH value from the pH of 4.5. Thus, the protein fully precipitates, and with subsequent decantation, high molecular weight proteins are completely separated from minerals, sugars, as well as other non-protein compounds. In practice, this leads to an increased yield of expensive protein by 3-4%.

Using, for example, FOAM BLAST 300K as an antifoam, it is possible to withstand all technological parameters with a high degree of accuracy at the extraction stage, which subsequently leads to high rates during decanting. In turn, a complete decanting of the incoming raw materials, at each subsequent stage, allows you to separate high molecular weight proteins with a molecular weight in the range of 1000-800000, with a decantation ratio of G factor 3625 × g and higher, up to a concentration of 90% + on dry matter.

As alkali, NaOH (10% -98%) is used, and acids are hydrochloric acid, which is subsequently associated with the use of the product in the food industry.

The proposed method is implemented as follows:

A metered amount of a white petal with a solubility index PDI of 55 to 95, with a thickness of a white petal or its waste from 0.1 microns to 1.5 mm, is fed to the top of the vertical pipe simultaneously with a solution of water, alkali and liquid phase from the second extraction containing water-soluble proteins -10-15%, sugars and minerals, in a gravitational swirling flow to completely soak the incoming petal without the formation of lumps.

Using a white petal with a solubility index of less than 55 reduces the protein yield, as a lot of low molecular weight protein goes into serum, and more than 95 is impossible with any method of obtaining a white petal.

Using a white petal with a thickness of less than 0.1 microns is impossible, because such a fine powder cannot be subjected to extraction, and more than 1.5 mm unjustifiably increases the extraction time, increasing technological costs.

In the process of soaking, an antifoam is added, since the formation of a large amount of foam is possible. FOAM BLAST 300K is used as a defoamer.

Alkali NaOH (10% -98%) is diluted in water to increase pH and improve protein solubility.

All this mass, already mixed and processed during a gravitational fall, enters the dissolution and mixing tank; then it is fed into the first extraction tank at a temperature (48 ° C-65 ° C) and pH (6.8-8.8), humidity 90%. The extraction time is from 2 minutes to 40 minutes, depending on the technological balance of the process. Precipitation in the liquid phase is not.

A decrease in the extraction temperature of less than 48 ° C and a pH of the process of less than 6.8 increases the extraction time and decreases the yield of protein, and an increase in the temperature of extraction of more than 65 ° C and a pH of the process of more than 8.8 is unacceptable, since in the future the raw materials stick to the equipment and denaturation of raw materials.

From the first extraction tank, the suspension is fed to a decanter centrifuge to separate extract 1 (the liquid phase containing the extracted protein, low molecular weight proteins and sugars) from the solid phase (containing insoluble carbohydrates - mainly fiber and unextracted proteins). Extract 1 is fed into the acid deposition vessel, and the solid phase is fed into the second extraction vessel, where it is mixed with water and process liquid to further more fully isolate residual proteins and sugars. During the second extraction, approximately 5-10% of proteins that did not dissolve during the first extraction are additionally dissolved in water.

The parameters of the second extraction: temperature (48 ° C-65 ° C) and pH (6.8-8.8), humidity 89-92%. The extraction time is from 2 minutes to 40 minutes, depending on the technological balance of the process. The precipitate of the liquid phase is 2-3%.

With a decrease in the solubility index PDI of less than 75 (at which protein losses already occur), and which is monitored on-line by a spectrometer, an additional system of “thermal shock dumping” is activated. The suspension is treated with sharp saturated steam over the entire cross section of the stream to ensure thorough mixing and uniform temperature distribution, which contributes to a sharp increase in temperature from 60 ° C to (82 ° -102 °) C. In this case, the pressure in the pipeline is maintained at (2.2-4.0) Bar for (0.5-2.5). Then sharply reduce the temperature to 48 ° C-65 ° C by directing the flow into a vacuum container.

This helps to enhance the effect of extracting protein from raw materials that could not be previously extracted. A further sharp decrease in the temperature of the extract to 48 ° C-65 ° C due to its directing to a vacuum container avoids protein denaturation and also enhances the ability to extract. This preserves a stable protein yield in the presence of high weediness of raw materials and low solubility index (PDI).

Moreover, the use of parameters less than the lower limit does not increase the protein yield, while increasing energy consumption. Using parameters above the upper limit leads to protein denaturation.

From the second extraction tank, the suspension is fed to a second decanter centrifuge, in which the second liquid phase is separated (extract 2 — containing additionally isolated 5-10% water-soluble proteins and sugar) from the second solid phase (containing insoluble carbohydrates - mainly fiber and residues of water-insoluble proteins). The liquid phase (extract 2) is fed to the beginning of the technological cycle of processing and dissolving the newly incoming raw materials, and the solid phase (at a humidity of about 80%) is fed to an intermediate tank.

The liquid phase with dissolved beams and sugars from the first extraction (extract 1) is fed into a tank for acid precipitation of proteins at a pH corresponding to the isoelectric point of soy proteins. To achieve a pH in the range of 4.45-4.55 hydrochloric acid HCL is added to the solution.

In this case, before the stage of acid deposition carry out preliminary mixing of the liquid phase with acid, for example already in the pipeline. This makes it possible to uniformly lower the pH of the liquid phase already at the stage of movement in the pipe before the extract enters the sedimentation tank. The practical advantage of such an introduction of acid leads to the fact that in the deposition tank there is no fluctuation of the pH values from the level of the isoelectric point equal to 4.5. This pH level, controlled by a special sensor (pH meter), known as the isoelectric point of soy proteins or the minimum protein solubility level, at which approximately 85% of soluble proteins precipitate (precipitate) and can be separated from soluble sugars and the so-called “whey” "Proteins.

Thus, the protein fully precipitates, and with subsequent decantation, high molecular weight proteins are completely separated from minerals and sugars, as well as other non-protein compounds. In practice, this leads to an increase in the yield of expensive protein by 3-4%.

Then, the precipitated suspension is kept for a certain time to mature and “calm” the proteins and fed to a decanter centrifuge to separate the liquid phase (whey), consisting of dissolved sugars and whey proteins and a solid phase containing precipitated proteins. Serum with a moisture content of 97% is sent to a clarifier separator, then to the evaporation system, where its moisture is reduced to 50%, and it is sent to the feed production site in the form of soy molasses.

To produce a high-quality isolate with a content of not less than 90% protein, a clot of precipitated proteins is washed once again with water for a better removal of sugars and minerals. Then the suspension is again sent to a centrifuge-decanter to separate the liquid phase (non-concentrated whey), consisting of residual dissolved sugars and minerals and a solid phase containing precipitated proteins. Unconcentrated whey enters the recirculation tank and is then used in the processing of raw materials, and the solid phase (precipitated protein) can be neutralized, modified, pasteurized, and removed bean odor. Then the product is spray-dried, and the dried product (isolate) in powder form with a moisture content of about 5-7% is fed to the packaging.

Product Feature.

The following examples illustrate the proposal of the applicant, without limiting the proposal on the merits.

Example 1. Get soy protein isolate with a solubility index PDI of 75, with a content of weeds in high-quality raw materials up to 30%. The thickness of the white petal and its waste (soy flour) is from 0.1 microns to 1.5 mm.

From the buffer tank, the amount of white petal dosed with a metering hopper - 5000 kg with a solubility index PDI - 75, is sent for processing in a gravitational swirling stream in a vertical pipe. In on-lain mode, the quality of the raw materials is analyzed by a spectrometer. In this case, an automatic system for analyzing the quality of raw materials received a signal of low PDI - less than 76. At the same time, water and liquid fraction begin to be supplied to the upper part of the vertical pipe from the condensate storage tank after decantation at the second extraction stage. The ratio of the supplied liquid for soaking and dissolving the white petal and raw materials is 1:10. Pure water makes up 2000 liters (up to 13% of the total amount of liquid supplied to soaking), the rest - 23000 liters - is a mixture of condensate and decantation liquid fraction after the second extraction. At the same time, alkali (40% NaOH) begins to be added to increase the pH level and improve the solubility of the protein. The alkali consumption is 180 liters per hour. A defoamer is added to the process of processing and soaking the white petal, since a large amount of foam can form. FOAM BLAST 300K is used as a defoamer.

Alkali NaOH (10% -98%) is diluted in water to increase pH and improve protein solubility.

All this mass, already mixed and processed during a gravitational fall, enters the first extraction tank. The parameters of the first extraction are temperature - 58 ° C, humidity - 90%, pH - 7.7, time - 40 minutes.

From the first extraction tank, the suspension is fed to a decanter centrifuge to separate extract 1 (the liquid phase containing the extracted protein and water-soluble proteins and sugars) from the solid phase (containing insoluble carbohydrates - mainly fiber and unextracted proteins). Extract 1 is fed into the acid deposition vessel, and the solid phase is fed into the second extraction vessel, where it is mixed with water and process liquid to further more fully isolate residual proteins and sugars. In the tank for the second extraction add 10,000 liters of condensate formed during the evaporation of molasses. The parameters of the second extraction: temperature - 60 ° C and pH - 7.3, humidity - 91%. The extraction time is 40 minutes.

Since at the beginning of the process, the automatic system recorded a low solubility index (PDI), an additional thermal shock dumping system is activated when the suspension is transported to the second extraction. The suspension is treated with hot steam, which contributes to a sharp increase in temperature from 60 ° C to 90 ° C, together with an increase in pressure in the pipeline to 2.8 Bar. The residence time of raw materials under the influence of sharp steam is up to 1 second. In this case, when the suspension enters the second extraction tank, its temperature drops sharply to 60 ° C.

From the second extraction tank, the suspension is fed to a second decanter centrifuge, in which the liquid phase (containing water-soluble proteins and sugars) is separated from the solid phase (containing insoluble carbohydrates - mainly fiber and residues of water-insoluble proteins). The liquid phase (extract 2) is fed to the beginning of the process, in order to process and soak the white petal, and the solid phase (at a moisture content of about 70%) is fed by a screw conveyor to the fiber drying system. The residual protein content in fiber is 8%, which indicates that using thermal dumping, it was possible to isolate an additional 15% of water-soluble proteins, which could not have been done without the use of thermal shock dumping.

Laboratory test results:

The liquid phase with dissolved beams and sugars after extraction and using it for soaking and treating the white petal is fed into the tank for acid precipitation of proteins at a pH corresponding to the isoelectric point of soy proteins. To achieve a pH in the range of 4.45-4.55 hydrochloric acid HCL is added to the liquid phase. At the same time, to achieve a pH level of exactly - 4.5, while the liquid is moving through the pipeline, it is pre-mixed with hydrochloric acid HCL - 35% .. This can significantly reduce the protein deposition time. An antifoam agent of 20 liters per hour is added to the acid deposition tank using a membrane pump to prevent the formation of excess foam. Since the required pH level is reached quickly, the suspension is not maintained for a long time in the acid deposition tank, but is fed immediately to a decanter centrifuge to separate the liquid phase (whey), consisting of dissolved sugars and whey proteins and a solid phase containing precipitated proteins. The parameters in the acid deposition tank are: temperature - 60 ° C, humidity - 89-90%, pH - 4.5.

Then, the precipitated suspension is kept for a certain time to mature and “calm” the proteins and fed to a decanter centrifuge to separate the liquid phase (whey), consisting of dissolved sugars and whey proteins and a solid phase containing precipitated proteins. Serum with a moisture content of 97% is sent to a clarifier separator, then to the evaporation system, where its moisture is reduced to 50%, and it is sent to the feed production site in the form of soy molasses.

To produce a high-quality isolate with a content of not less than 90% protein, a clot of precipitated proteins is washed once again with water for a better removal of sugars and minerals. Then the suspension is again sent to a centrifuge-decanter to separate the liquid phase (non-concentrated whey), consisting of residual dissolved sugars and minerals and a solid phase containing precipitated proteins. Unconcentrated whey enters the recycling tank and is then used in the processing of raw materials, and the solid phase (precipitated protein) can be neutralized, modified, pasteurized, and removed bean odor. Then the product is spray dried, and the dried product (isolate) in powder form with a moisture content of about 5% is fed to the packaging. The total need for water make-up will be about 5000 liters per hour.

Volume and characteristics of products (per hour):

The protein yield is 45% relative to the low quality raw materials used, which is not possible in other technologies, protein losses will exceed 15% or more.

Example 2. Get soy protein isolate with a solubility index PDI of 80, with a content of weeds in high-quality raw materials up to 30%. The thickness of the white petal and its waste (soy flour) is from 0.1 microns to 1.0 mm.

From the buffer tank, the quantity of a white petal dosed with a dosing hopper - 5000 kg with a solubility index PDI - 80, is sent for processing in a gravitational swirling stream in a vertical pipe. In on-lain mode, the quality of the raw materials is analyzed by a spectrometer. In this case, an automatic system for analyzing the quality of raw materials received a signal of PDI - 80. At the same time, water and liquid fraction begin to be supplied to the upper part of the vertical pipe from the condensate storage tank after decantation at the second extraction stage. The ratio of the supplied liquid for soaking and dissolving the white petal and raw materials is 1:10. Pure water makes up 2000 liters (up to 13% of the total amount of liquid supplied to soaking), the rest - 23000 liters - is a mixture of condensate and decantation liquid fraction after the second extraction. At the same time, alkali (40% NaOH) begins to be added to increase the pH level and improve the solubility of the protein. The alkali consumption is 180 liters per hour. A defoamer is added to the process of processing and soaking the white petal, since a large amount of foam can form. FOAM BLAST 300K is used as an antifoam.

Alkali NaOH (10% - 98%) is diluted in water to increase pH and improve protein solubility. All this mass, already mixed and processed during a gravitational fall, enters the first extraction tank. The parameters of the first extraction are temperature - 58 ° С, humidity - 90%, pH -7.5, time - 20 minutes.

From the first extraction vessel, the suspension is fed to a decanter centrifuge to separate extract 1 (containing water-soluble proteins and sugars) from the solid phase (containing insoluble carbohydrates - mainly fiber and unextracted proteins). Extract 1 is fed into the acid deposition vessel, and the solid phase is fed into the second extraction vessel, where it is mixed with water and process liquid to further more fully isolate residual proteins and sugars. In the tank for the second extraction add 10,000 liters of condensate formed during the evaporation of molasses. The parameters of the second extraction: temperature - 60 ° C and pH - 7.3, humidity - 91%. The extraction time is 20 minutes.

Since the automatic system did not record a low solubility index (PDI) at the beginning of the process, no additional thermal shock dumping system is used to transport the suspension to the second extraction.

From the second extraction tank, the suspension is fed to a second decanter centrifuge, in which the liquid phase (containing water-soluble proteins and sugars) is separated from the solid phase (containing insoluble carbohydrates - mainly fiber and residues of water-insoluble proteins). The liquid phase (extract 2) is fed to the beginning of the process, in order to process and soak the white petal, and the solid phase (at a moisture content of about 70%) is fed by a screw conveyor to the fiber drying system.

The liquid phase with dissolved beams and sugars after extraction and using it for soaking and treating the white petal is fed into the tank for acid precipitation of proteins at a pH corresponding to the isoelectric point of soy proteins. To achieve a pH in the range of 4.45-4.55 hydrochloric acid HCL is added to the liquid phase. Moreover, in order to achieve a pH level of exactly - 4.5, during the movement of the liquid through the pipeline, it is pre-mixed with hydrochloric acid HCL - 35%. This can significantly reduce the protein deposition time. An antifoam agent of 20 liters per hour is added to the acid deposition tank using a membrane pump to prevent the formation of excess foam. Since the required pH level is reached quickly, the suspension is not maintained for a long time in the acid deposition tank, but is fed immediately to a decanter centrifuge to separate the liquid phase (whey), consisting of dissolved sugars and whey proteins and a solid phase containing precipitated proteins. The parameters in the acid deposition tank are: temperature - 60 ° C, humidity - 89-90%, pH - 4.5.

Then, the precipitated suspension is kept for a certain time to mature and “calm” the proteins and fed to a decanter centrifuge to separate the liquid phase (whey), consisting of dissolved sugars and whey proteins and a solid phase containing precipitated proteins. Serum with a moisture content of 97% is sent to a clarifier separator, then to the evaporation system, where its moisture is reduced to 50%, and it is sent to the feed production site in the form of soy molasses.

To produce a high-quality isolate with a content of not less than 90% protein, a clot of precipitated proteins is washed once again with water for a better removal of sugars and minerals. Then the suspension is again sent to a centrifuge-decanter to separate the liquid phase (non-concentrated whey), consisting of residual dissolved sugars and minerals and a solid phase containing precipitated proteins. Unconcentrated whey enters the recycling tank and is then used in the processing of raw materials, and the solid phase (precipitated protein) can be neutralized, modified, pasteurized, and removed bean odor. Then the product is spray dried, and the dried product (isolate) in powder form with a moisture content of about 5% is fed to the packaging. The total need for water make-up will be about 5000 liters per hour.

Volume and characteristics of products (per hour):

The protein yield is 45% relative to the raw materials used. Loss of protein is reduced by 15% compared with known technologies.

Claims (11)

1. A method of obtaining soy protein isolate from a white petal, including the supply of raw materials, water and alkali to obtain a suspension of soy protein, obtaining a suspension of soy protein by dissolving the raw material in an aqueous alkaline solution, extracting the resulting suspension, separating the extract, acid precipitation of proteins at pH, the corresponding isoelectric point of soy proteins, the separation of serum from the precipitated proteins, washing the precipitated proteins, drying and packaging of the finished product, characterized in that using raw materials with a solubility index PDI of 55 to 95, with a white petal or its waste thickness of 0.1 microns to 1.5 mm, before dissolving the raw material, it is subjected to its aqueous-alkaline treatment in a gravitational swirling flow, while the raw materials, water and alkali are fed to the beginning of the flow, extraction is carried out in two stages at a temperature (48 ° C-65 ° C) and pH (6.8-8.8), the liquid phase formed in the process of protein isolation is used in the processing and dissolution of raw materials, with a decrease in the solubility index PDI of less than 75 after the second extraction, the suspension is treated with hot steam at a temperature of (82 ° C-102 ° C). pressure (2.2-4.0) Bar for a time excluding protein denaturation, and then sharply reduce the temperature to 48 ° C-65 ° C, and prior to the acid deposition step, preliminary mixing of the liquid phase with the acid is carried out. 2. The method according to claim 1, characterized in that when processing raw materials in a gravitational swirling flow, an antifoam is added, which is used as FOAM BLAST 300 K. 3. The method according to claim 1, characterized in that (10% -98%) NaOH is used as alkali. 4. The method according to claim 1, characterized in that the acid deposition of proteins is hydrochloric acid. 5. The product obtained by the method according to claim 1.