Instant soybean flour with no additives, high protein and one-step brewing forming and its preparation process

Abstract

The application provides instant soybean flour powder without additives, high in protein and capable of being shaped by one-step brewing, and a preparation process thereof, comprising the following steps: soaking soybeans in pure water, finely grinding and polishing, and centrifugally removing residues to obtain first soybean milk; then, the first soybean milk is punched into an enzymolysis tank, and a beta-amylase solution is added for enzymolysis to obtain second soybean milk; the second soybean milk is boiled, cooled, concentrated, spray-dried and screened to obtain soybean flour powder, which is mixed with gluconic acid-delta-lactone, and then packaged to obtain instant soybean flour powder. The application adopts an amylase enzymolysis process to enzymolyze soybean starch. The soybean starch is converted into maltose syrup after enzymolysis, which can reduce viscosity and improve solubility, so that the soybean flour powder is quickly dispersed and dissolved, and can be directly reacted with a coagulating agent to be shaped. In addition, part of the combined protein can be released after reaching a certain degree of enzymolysis, so as to increase the interaction between proteins and promote coagulation and shaping. The soybean flour powder of the application is without additives, high in protein, and capable of being directly brewed and shaped, and has good coagulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of instant soybean flour, and particularly relates to instant soybean flour without additives, high in protein and capable of being formed by one-step brewing, and a preparation process thereof. BACKGROUND

[0002] Soybean has high nutritional value, with a protein content of up to 40%, and contains essential amino acids for human body, and is the high-quality protein closest to the proportion of amino acids required by human body among plant products. In addition, soybean has a high content of unsaturated fatty acids, contains essential linoleic acid for human body, and has a low content of cholesterol, and can prevent arteriosclerosis. Soybean oligosaccharides can promote the reproduction of probiotics such as bifidobacterium in the intestinal tract, have the effect of lubricating the intestines and defecating, can prevent rectal cancer, improve human immunity, and delay aging. In addition, soybean isoflavones are phytoestrogens, and long-term consumption can prevent diseases such as breast cancer, prostate cancer, and osteoporosis, and reduce or avoid menopausal syndrome. Soybean lecithin has the effects of anti-aging and brain health.

[0003] The instant soybean flour is prepared from soybean, is not only rich in nutritional value, convenient to use, and has a long shelf life, but also can be transported and stored for a long time, and thus can meet the social demand for convenience. At present, the instant soybean flour on the market has the following two forming modes:

[0004] I. Direct brewing and heat preservation forming: the coagulant is mixed with the instant soybean flour in advance and packaged, and then is brewed with boiling water according to a water-to-powder ratio of 5-7:1, and is formed after heat preservation for about 10 minutes. This mixed type of soybean flour adds a large amount of malt syrup, white sugar, malt dextrin and other seasonings in the production process to reduce the astringent taste after forming, and the protein content is low, which is 12%-15%, and does not meet the anti-sugar demand of consumers.

[0005] II. Water boiling forming or two-step heat preservation forming: the instant soybean flour is dissolved in warm water, is boiled, then the heating is stopped, is cooled to about 90℃, and then is added with glucono-delta-lactone, and is formed after heat preservation for 15-20 minutes; or the instant soybean flour is brewed with boiling water according to a water-to-powder ratio of 8-12:1, is heat preserved for 10-15 minutes, then is added with glucono-delta-lactone, and is formed after further heat preservation for 15-20 minutes. The protein content of this type of soybean flour is as high as 30%-40%, and only malt dextrin or no additives are added in the production process, the ingredients are simple, and the nutritional value is high, but the forming agent and the soybean flour are separately dissolved, the production mode is complex, and the production time is long. SUMMARY

[0006] The present application aims to provide instant soybean flour without additives, high in protein and capable of being formed by one-step brewing, which can be directly formed by one-step brewing, and is without additives and high in protein.

[0007] Another object of the present application is to provide a preparation process of instant soybean flour without additives, high in protein and capable of being shaped by one-step brewing, which adopts a starch enzymolysis process to enzymolyze soybean starch, so that the prepared soybean flour is fast in dispersion and dissolution and can be directly reacted with a coagulant to be shaped, the method parameters are controllable and suitable for industrial large-scale production.

[0008] The present application solves its technical problem by adopting the following technical solution.

[0009] The present application provides a preparation process of instant soybean flour without additives, high in protein and capable of being shaped by one-step brewing, which comprises the following steps:

[0010] S1, soaking soybeans in pure water, finely grinding and polishing, and centrifugally removing residues to obtain first soybean milk;

[0011] S2, punching the first soybean milk into an enzymolysis tank, adding a beta-amylase solution to perform enzymolysis, and obtaining second soybean milk;

[0012] S3, performing boiled soybean milk, cooling, concentration, spray drying and powder screening on the second soybean milk to obtain soybean flour;

[0013] S4, mixing the soybean flour with glucono-delta-lactone, and packaging to obtain instant soybean flour without additives, high in protein and capable of being shaped by one-step brewing.

[0014] The present application provides instant soybean flour without additives, high in protein and capable of being shaped by one-step brewing, which is prepared according to the above preparation process, and the instant soybean flour is brewed with pure water, and is fast stirred in the same direction for 3-5 seconds to be fully dissolved, and is kept warm and placed for 10-15 minutes to be edible, wherein the mass ratio of the pure water to the instant soybean flour is 8-10:1 during brewing, and the temperature of the pure water is not lower than 90 DEG C.

[0015] The instant soybean flour without additives, high in protein and capable of being shaped by one-step brewing and the preparation process thereof have the following beneficial effects:

[0016] The present application adopts a starch enzymolysis process to enzymolyze soybean starch after soybean soaking, fine grinding and polishing and centrifugal residue removal. The soybean starch is converted into maltose syrup after enzymolysis, which can reduce viscosity and improve solubility, so that the soybean flour is fast in dispersion and dissolution and can be directly reacted with a coagulant to be shaped. In addition, part of the combined protein can be released after reaching a certain degree of enzymolysis, so as to increase the interaction between proteins and promote coagulation and shaping. The soybean flour prepared by the process of the present application is high in protein and has high nutritional value, and can be directly brewed and shaped with good coagulation. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those of ordinary skill in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0018] Figure 1 Preparation flow chart of the instant soybean flour provided by the present application, which is additive-free, high-protein and can be molded by one-step brewing.

[0019] Figure 2 Schematic diagram of the placement points of the alcohol soybean flour steel sheet for each pot in test example 1. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be obtained by market purchase.

[0021] The additive-free, high-protein and instant soybean flour provided by the embodiments of the present application and the preparation process thereof will be described in detail below.

[0022] Referring to Figure 1 The preparation process of the additive-free, high-protein and instant soybean flour provided by the embodiments of the present application includes the following steps:

[0023] S1, the soybeans are soaked in pure water, and after fine grinding, centrifugal de-sludging, a first soybean milk is obtained. The soybeans used in the present application are selected from high-protein first-grade beans. Before soaking, the soybeans are cleaned and impurities are removed for standby, and then the soybeans are soaked in normal temperature pure water (RO water). The surface of the soaked soybeans is bright, without wrinkles, and the bean skin does not fall off easily, and the finger pinches it easily broken, and the cross section is soaked without hard core.

[0024] Further, in the preferred embodiments of the present application, the mass ratio of the soybeans to the pure water is 1:2-2.5, the soaking time in summer is 6-8h, and the soaking time in winter is 12-16h.

[0025] Further, in the preferred embodiment of the present application, after the soaked soybeans are refined using the refining water, the material is obtained by passing through an 80-mesh screen, and then the material is pumped into a horizontal screw separator for sludge separation to obtain the first soybean milk, wherein the temperature of the refining water is 70-80℃, the pH of the refining water is 6.8-7.0, the mass percentage of the first soybean milk is 11-12%, and the sludge content of the first soybean milk is ≤5%. In the present application, the concentration of the soybean milk during the sludge removal is controlled to be 9-10%, and the concentration of the first soybean milk obtained after the sludge removal is 11-12%, and the sludge content of the first soybean milk is ≤5%.

[0026] S2, the first soybean milk is poured into an enzyme hydrolysis tank, and a β-amylase solution is added for enzyme hydrolysis to obtain second soybean milk.

[0027] Further, in the preferred embodiment of the present application, in the β-amylase solution, the mass ratio of β-amylase to warm water is 1:95-105, and the mass ratio of the β-amylase solution to the first soybean milk is 5×10 -5 -2×10 -4 :1, wherein the activity of the β-amylase is 20000U. Preferably, the mass ratio of β-amylase to warm water is 1:100.

[0028] Further, in the preferred embodiment of the present application, the temperature of the enzyme hydrolysis is 40-60℃, the enzyme hydrolysis time is 30-120min, and the enzyme hydrolysis rate is 65-75%. In the present application, the steps for determining the enzyme hydrolysis rate are as follows: first, sampling and enzyme inactivation (after the soybean milk is taken, it is boiled to boiling, and the boiling is continued for 30-60 seconds to complete the enzyme inactivation process), and then the starch contents in the soybean milk before and after the enzyme hydrolysis are tested according to the first method in GB5009.9, and the enzyme hydrolysis rate = (starch content after enzyme hydrolysis) / (starch content before enzyme hydrolysis)*100%. The enzyme hydrolysis rate of the present application is 65-75%, and the instant soybean flower powder prepared at the enzyme hydrolysis rate can be quickly dissolved and dispersed, and also has good protein coagulation and taste.

[0029] S3, the second soybean milk is cooked, cooled, concentrated, spray dried, and sieved to obtain soybean flower powder.

[0030] Further, in the preferred embodiment of the present application, the steps of cooking and cooling the second soybean milk are as follows: the second soybean milk is cooked to 90-100℃ and then incubated for 3-8min, and then filtered through a vibrating screen 160-mesh filter screen and cooled to 30-40℃ in a cooling tank. Preferably, the present application uses a heat exchanger to cool the slurry after cooking to 30-40℃.

[0031] Further, in the preferred embodiment of the present application, the concentration uses a three-effect multi-stage evaporator, wherein the pressure of the first-effect evaporator is -0.06-0.08 MPa, the evaporation temperature is 60-70 DEG C, the pressure of the second-effect evaporator is -0.07-0.09 MPa, the evaporation temperature is 50-60 DEG C, the pressure of the third-effect evaporator is -0.08-0.10 MPa, the evaporation temperature is 40-50 DEG C, and the concentration of the concentrated material is 45-50%.

[0032] Further, in the preferred embodiment of the present application, the spray drying has an air inlet temperature of 100-130 DEG C, an air outlet temperature of 60-75 DEG C, a fluidized bed four-section temperature of 20-30 DEG C, a steam pressure of 0.3-0.8 MPa, and a high-pressure pump pressure of 5-20 MPa. The present application uses a fluidized bed powder screen after the spray drying, the powder outlet temperature is 30-40 DEG C, the vibrating screen mesh number is 20 meshes, and the soybean flower powder is obtained after the powder screening.

[0033] S4, the soybean flower powder and gluconic acid-delta-lactone are mixed, and the added-free, high-protein and one-step forming instant soybean flower powder is obtained after the packaging.

[0034] Further, in the added-free, high-protein and one-step forming instant soybean flower powder, the mass percentage of the soybean flower powder is 95-96%. The mixing equipment used in the present application is a three-dimensional mixer or a V-shaped mixer, the mixing time is 15-30 min, the uniform mixing is ensured, and the instant soybean flower powder is obtained. After the mixing is completed, the packaging is performed according to the net content of 30 g / bag, the packaging material is PET12 / AL7 / CPE85, the shelf life is 12 months, and the storage condition is a cool and dry place, and the storage temperature is lower than 25 DEG C.

[0035] The production process of the present application comprises the following steps: soybean soaking, fine grinding, centrifugal deslagging, enzymatic hydrolysis, cooking, cooling, concentration, spray drying, fluidized bed powder screening, mixing, and packaging. After the soybean soaking, fine grinding and centrifugal deslagging, the starch of the soybean is subjected to the enzymatic hydrolysis. The soybean starch is converted into maltose syrup after the enzymatic hydrolysis, the viscosity is reduced, and the solubility is improved, so that the soybean flower powder is dispersed and dissolved quickly, and can be directly reacted with a coagulating agent to form a shape. In addition, a part of the combined protein is released after a certain degree of enzymatic hydrolysis, so that the interaction between the proteins is increased, and the coagulation forming is promoted. However, if the degree of enzymatic hydrolysis is too high, the starch is reduced, the stability of the soybean milk emulsion is reduced, the emulsification effect is poor, the oil on the surface of the soybean flower powder is possibly increased, so that the quick dissolution and dispersion of the soybean flower powder and the gel forming of the protein are not conducive, and the forming and taste are poor. The soybean flower powder prepared by the process of the present application is added-free, high-protein, high in nutritional value, and can be directly mixed to form a shape, and has good coagulation.

[0036] The application further provides the instant soybean flour prepared according to the preparation process, which is added with no additives and high in protein and can be shaped and formed by one-step brewing, and is brewed with pure water and stirred in the same direction for 3-5 seconds to be fully dissolved, and can be eaten after being kept warm and standing for 10-15 minutes, wherein the mass ratio of the pure water to the instant soybean flour is 8-10:1, and the temperature of the pure water is not lower than 90 DEG C.

[0037] The features and performances of the application are further described in detail in combination with the following examples.

[0038] Example 1

[0039] The application provides the instant soybean flour prepared according to the following method.

[0040] (1) Soybean soaking: high-protein first-grade soybeans are selected, cleaned and impurities are removed, and then soaked in 2 times of mass of normal-temperature RO water for 8 hours. The surface of the soaked soybeans is bright, and the skin is not easy to fall off, and the soybeans are easy to break when pinched by fingers, and the broken surface is fully soaked without hard core.

[0041] (2) Fine grinding and centrifugal dreg removal: the water temperature of the grinding water is adjusted to 70 DEG C, and the slurry PH is 6.8-7.0. After fine grinding, the material is greater than or equal to 85% through an 80-mesh screen. Then the material is pumped into a horizontal screw separator for slurry-dreg separation, and the slurry concentration is controlled to be 9-10% during dreg removal. After dreg removal, the first soybean slurry is obtained, and the dreg content is less than or equal to 5%, and the soybean slurry concentration is 11-12%.

[0042] (3) Enzymolysis: the first soybean slurry is pumped into an enzyme hydrolysis tank, and β-amylase (activity of 20,000 U) is pre-dissolved in warm water at a mass ratio of 1:100, and then added into the enzyme hydrolysis tank for hydrolysis. The addition amount is 0.05% of the mass of the slurry, the hydrolysis time is 40 minutes, and the hydrolysis temperature is 50 DEG C. The second soybean slurry is obtained, and the hydrolysis rate is 65%.

[0043] (4) Slurry boiling and cooling: the second soybean slurry is boiled to 100 DEG C, and kept warm for 3 minutes. Then the slurry is filtered through a vibrating screen 160-mesh filter screen, and kept in a cooling tank for standby. The cooling equipment adopts a heat exchanger, and the slurry temperature is 40 DEG C after cooling.

[0044] (5) Concentration: the above cooled slurry is concentrated by using a three-effect multi-stage evaporator. The pressure of the first-effect evaporator is-0.06 MPa, and the evaporation temperature is 70 DEG C. The pressure of the second-effect evaporator is 0.09 MPa, and the evaporation temperature is 50 DEG C. The pressure of the third-effect evaporator is 0.10 MPa, and the evaporation temperature is 50 DEG C. The concentration of the material after concentration is 45%.

[0045] (6) Spray drying and fluidized bed screening: the concentrated material is subjected to spray drying, with an inlet air temperature of 100°C, an exhaust air temperature of 75°C, a fluidized bed four-stage temperature of 20°C, a steam pressure of 0.3 MPa, and a high-pressure pump pressure of 5 MPa. Then, the material is subjected to fluidized bed screening to obtain bean flower powder, which is stored in a powder storage bin. The powder outlet temperature is 30-40°C, and the vibration screen mesh size is 20 mesh.

[0046] (7) Mixing and packaging: the bean flower powder is mixed with δ-lactone according to a ratio of 95%-96% to 4%-5%, using a three-dimensional mixer for 30 minutes to ensure uniform mixing. After mixing, the material is packaged according to a net content of 30 g per package, using PET12 / AL7 / CPE85 packaging materials, with a shelf life of 12 months and storage conditions of a cool, dry place with a storage temperature of less than 25°C, to obtain instant bean flower powder.

[0047] (8) Instant bean flower preparation: hot water is used to prepare the instant bean flower according to a water to powder ratio of 8:1, with a water temperature of ≥90°C and pure water. During preparation, the material is quickly stirred in the same direction for 3-5 seconds until the bean flower powder is fully dissolved, and then the material is left to stand for 10 minutes before being consumed.

[0048] Example 2

[0049] This example provides a kind of instant bean flower powder without adding, high protein and can be one-step preparation, which is different from example 1 in that:

[0050] Enzymolysis: the first soybean milk is poured into an enzyme hydrolysis tank, β-amylase (activity of 20,000 U) is pre-dissolved in warm water according to a ratio of 1:100 by weight, and then added to the enzyme hydrolysis tank for enzyme hydrolysis, with an addition amount of 0.05 parts per million of the mass of the slurry, an enzyme hydrolysis time of 50 minutes, and an enzyme hydrolysis temperature of 50°C. The second soybean milk obtained has an enzyme hydrolysis rate of 70%.

[0051] Example 3

[0052] This example provides a kind of instant bean flower powder without adding, high protein and can be one-step preparation, which is different from example 1 in that:

[0053] Enzymolysis: the first soybean milk is poured into an enzyme hydrolysis tank, β-amylase (activity of 20,000 U) is pre-dissolved in warm water according to a ratio of 1:100 by weight, and then added to the enzyme hydrolysis tank for enzyme hydrolysis, with an addition amount of 0.05 parts per million of the mass of the slurry, an enzyme hydrolysis time of 60 minutes, and an enzyme hydrolysis temperature of 55°C. The second soybean milk obtained has an enzyme hydrolysis rate of 75%.

[0054] Comparative Example 1

[0055] This comparative example provides an instant bean flower powder, which is different from example 1 in that the enzyme hydrolysis rate in step (3) is 50%.

[0056] Comparative Example 2

[0057] This comparative example provides an instant tofu powder, which differs from Example 1 in that the enzymatic hydrolysis rate in step (3) is 55%.

[0058] Comparative Example 3

[0059] This comparative example provides an instant tofu powder, which differs from Example 1 in that the enzymatic hydrolysis rate in step (3) is 60%.

[0060] Comparative Example 4

[0061] This comparative example provides an instant tofu powder, which differs from Example 1 in that the enzymatic hydrolysis rate in step (3) is 80%.

[0062] Comparative Example 5

[0063] This comparative example provides an instant tofu powder, which differs from Example 1 in that the enzymatic hydrolysis rate in step (3) is 85%.

[0064] Comparative Example 6

[0065] This comparative example provides an instant tofu powder, which differs from Example 1 in that the enzymatic hydrolysis rate in step (3) is 90%.

[0066] Comparative Example 7

[0067] This comparative example provides an instant soy pudding powder with a protein content of 40% and soybeans as the main ingredient. This instant soy pudding powder is the Xin Yan brand and is commercially available.

[0068] Comparative Example 8

[0069] This comparative example provides an instant tofu powder with a protein content of 30%, and its ingredients are soybeans and maltodextrin. This instant tofu powder is Jinlongyu instant tofu powder, which is commercially available.

[0070] Comparative Example 9

[0071] This comparative example provides an instant tofu powder with a protein content of 9%, and its ingredients include soybeans, maltose syrup, glucono-delta-lactone, and calcium carbonate. This instant tofu powder is from DouShiJi Tofu Pudding and is commercially available.

[0072] Comparative Example 10

[0073] This comparative example provides an instant tofu powder with a protein content of 15.5%, and its ingredients include soybeans, maltose syrup, white sugar, glucono-delta-lactone, maltodextrin, and sorbitan tristearate. This instant tofu powder is a type of instant tofu pudding from Beidahuang, and it is commercially available.

[0074] Test Example 1

[0075] In this test example, the instant soybean flour of Examples 1-3 and the instant soybean flour of Comparative Examples 1-10 were subjected to coagulation tests. The tools used in the test included an insulated bucket (the insulation effect at room temperature should be such that 1.5 L of boiling water poured into the insulated bucket, covered with a lid, and after standing for 5 minutes, the temperature is still higher than 82°C); a manual egg beater; a stainless steel sheet a (diameter 35 mm, thickness 2 mm, shaft diameter 3 mm, shaft length about 20 mm); a stainless steel sheet b (thickness 0.8 mm, diameter 34 mm, 32 mm, 30 mm, 28 mm, 26 mm, center hole diameter 5 mm).

[0076] The specific steps of the test were as follows:

[0077] Soybean flower making: 13 insulated buckets were taken and 2 L of boiled purified water was added to each of the buckets, then 200 g of the instant soybean flour of Examples 1-3 or Comparative Examples 1-10 was added to each of the buckets, respectively, and the soybean flour was quickly stirred for 3-5 seconds until it was fully dissolved. The lid was immediately covered and the mixture was kept warm for 15 minutes. After the making was completed, 5 pieces of stainless steel sheet b (diameter 26 mm-34 mm) were stacked on the stainless steel sheet a in the order of decreasing diameter, and then the stacked stainless steel sheets were gently placed on the coagulated soybean flower. When placing the stainless steel sheets, the force should be balanced to ensure that the soybean flower was evenly stressed. The stainless steel sheets were left on the surface of the soybean flower for 5 seconds, and whether the coagulated soybean flower around the stainless steel sheets was broken was observed. The placement points of the stainless steel sheets in each pot of soybean flower were as shown in the following table. Figure 2 The pass judgment standard of this test example was that the number of cracks was less than 3, which was determined to be qualified.

[0078] In this test example, the instant soybean flour of Examples 1-3 and the instant soybean flour of Comparative Examples 1-10 were evaluated and scored according to the test method in GB / T 25005. The evaluation and scoring rules are shown in Table 1, and the coagulation test results and evaluation and scoring results are shown in Table 2.

[0079] Table 1 Evaluation and Scoring Rules

[0080]

[0081] Table 2 Coagulation Test Results and Evaluation and Scoring Results

[0082]

[0083]

[0084] From table 2, the enzymolysis rate of the bean flower powder of the application is 60%-80%, the coagulation is qualified, the taste comprehensive score is greater than or equal to 26, the color is bright, the bean fragrance is rich, and the taste is smooth and elastic; the enzymolysis rate is 65%-75%, the taste comprehensive score is greater than or equal to 28, the color is bright, the bean fragrance is rich, the taste is smooth and elastic, and there is no sour taste, no peculiar smell, and the bean flower is pure in taste; lower than 60% or higher than 80%, the coagulation is unqualified, the forming is tender, the taste is soft, and the taste comprehensive score is low; the comparative example 7 has high protein content, no addition, and rich bean fragrance, but one-step preparation is not formed, the coagulation is unqualified, and the forming can be formed after boiling and then adding coagulant; the comparative example 8 has high protein content, but the forming is poor, the bottom is tender after forming, the upper part is honeycomb-shaped, the smoothness is poor, the coagulation is unqualified, and the taste comprehensive score is low; the comparative examples 9 and 10 are too tender under the condition of water powder ratio 10:1, almost not formed, the coagulation is unqualified, and the taste is sour, the sweetness is high, and the taste comprehensive score is low.

[0085] In summary, the instant bean flower powder prepared by the application is high in protein, has no addition, and can be formed by one-step preparation, and the coagulation and taste are better than those of the commercially available bean flower powder. In order to ensure that the bean flower product is qualified in coagulation and has authentic taste, and to improve the preference and repurchase rate of consumers, the enzymolysis rate needs to be controlled to be 65%-75%.

[0086] The above-described embodiments are part of the embodiments of the application, rather than all the embodiments. The detailed description of the embodiments of the application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

Claims

1. A process for the preparation of instant soy flour having high protein content, free from additives and capable of being prepared in a single step, characterized in that, The preparation process comprises the following steps: S1, soaking soybeans in pure water, fine grinding and centrifugal dreg removal to obtain first soybean milk; S2, adding β-amylase solution to the first soybean milk in an enzyme hydrolysis tank to perform enzyme hydrolysis, to obtain second soybean milk, and the enzyme hydrolysis rate is 65-75%; S3, the second soybean milk is boiled, cooled, concentrated, spray dried and sieved to obtain bean flower powder; S4, the bean flower powder and glucono-delta-lactone are mixed and packaged to obtain instant bean flower powder with no additives, high protein and one-step forming.

2. The manufacturing process according to claim 1, characterized in that, In step S1, the mass ratio of the soybeans to the pure water is 1:2-2.5, the soaking time is 6-8 hours in summer and 12-16 hours in winter.

3. The manufacturing process of claim 1, wherein, In step S1, the fine grinding and the centrifugal dreg removal are performed as follows: the soaked soybeans are fine ground with grinding water, and then passed through an 80-mesh screen to obtain material, and then the material is pumped into a horizontal screw separator to separate the pulp and the dregs, to obtain the first soybean milk, wherein the temperature of the grinding water is 70-80°C, the pH is 6.8-7.0, the concentration of the first soybean milk is 11-12%, and the dreg content is ≤5%.

4. The manufacturing process of claim 1, wherein, In step S2, the mass ratio of the β-amylase to the warm water in the β-amylase solution is 1:95~105, and the mass ratio of the β-amylase solution to the first soybean milk is 5×10 -5 ~2×10 -4 :1, wherein the activity of the β-amylase is 20000U.

5. The manufacturing process of claim 1, wherein, In step S2, the temperature of the enzyme hydrolysis is 40-60°C, and the enzyme hydrolysis time is 30-120 minutes.

6. The manufacturing process of claim 1, wherein, In step S3, the boiling and cooling of the second soybean milk are performed as follows: the second soybean milk is boiled to 90-100°C and kept for 3-8 minutes, and then filtered through a vibrating screen with a 160-mesh filter screen and cooled to 30-40°C in a cooling tank.

7. The manufacturing process of claim 1, wherein, In step S3, the concentration is performed by using a three-effect multi-stage evaporator, wherein the pressure of the first-effect evaporator is -0.06 to -0.08 MPa, and the evaporation temperature is 60-70°C; the pressure of the second-effect evaporator is -0.07 to -0.09 MPa, and the evaporation temperature is 50-60°C; the pressure of the third-effect evaporator is -0.08 to -0.10 MPa, and the evaporation temperature is 40-50°C; and the concentration of the material after concentration is 45-50%.

8. The manufacturing process of claim 1, wherein, In step S3, the inlet air temperature of the spray drying is 100-130°C, the exhaust air temperature is 60-75°C, the temperature of the four sections of the fluidized bed is 20-30°C, the steam pressure is 0.3-0.8 MPa, and the pressure of the high-pressure pump is 5-20 MPa.

9. The manufacturing process of claim 1, wherein, In step S4, the mass percentage of the bean flower powder in the instant bean flower powder with no additives, high protein and one-step forming is 95-96%.

10. A ready-to-eat soy flour having no additives, high protein and being formed by one-step brewing, characterized in that, The instant bean flower powder with no additives, high protein and one-step forming prepared by the preparation process of any one of claims 1-9 is mixed with pure water, and stirred in the same direction for 3-5 seconds to fully dissolve, and then kept for 10-15 minutes before being eaten, wherein the mass ratio of the pure water to the instant bean flower powder with no additives, high protein and one-step forming is 8-10:1, and the temperature of the pure water is not lower than 90°C.

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