Nattokinase powder based on superfine grinding of natto as well as preparation method and application of nattokinase powder

Abstract

The invention belongs to the technical field of nattokinase, and particularly discloses nattokinase powder based on superfine grinding of natto as well as a preparation method and application thereof, and the preparation method comprises the following steps: S1, uniformly mixing natto and a protective agent, spreading the mixture in a container, and pre-freezing for 2-24 hours to obtain pretreated natto; s2, transferring the natto into a freeze dryer, and sequentially performing normal-pressure cooling, vacuum heating and normal-pressure heating treatment to obtain freeze-dried natto; s3, transferring the anti-caking agent and the freeze-dried natto into a crusher, crushing and sieving to obtain crude natto powder; and S4, transferring the crude natto powder to a jet mill, and performing crushing, sieving and packaging to obtain the nattokinase powder. According to the nattokinase powder based on superfine grinding of natto as well as the preparation method and the application of the nattokinase powder, the specific surface area is increased, so that surface active groups are exposed, the adsorbability and the solubility are enhanced, the eating feeling of a beverage is improved, and the absorption rate of nattokinase is further increased after the beverage is eaten.

Description

Technical Field

[0001] This invention relates to the field of nattokinase technology, and in particular to a nattokinase powder based on ultrafine natto pulverization, its preparation method, and its application. Background Art

[0002] Natto is a product made from soybeans, which are steamed and then fermented with a pure strain of Bacillus natto. During fermentation, natto produces nattokinase, vitamin K, and other active substances. Nattokinase can reduce blood viscosity, dissolve blood clots, and help prevent cardiovascular and cerebrovascular diseases. It also improves protein digestibility and absorption, benefiting gastrointestinal health, and has a certain effect on strengthening the body and boosting immunity. Furthermore, the vitamin K in natto is more easily absorbed by bones and blood vessels, activating osteocalcin, promoting calcium deposition in bones, and reducing the risk of osteoporosis.

[0003] Traditional natto's fermented taste and sticky texture lead to poor public acceptance. Furthermore, natto needs to be refrigerated (0-4℃) and should be consumed as soon as possible after opening. Improper consumption or storage of natto can destroy its active substances, such as nattokinase.

[0004] In existing technologies, ultrafine grinding technology is an emerging technology that uses external forces (such as impact force, friction force, and shear force) to overcome the binding force inside the material, so that the particles are continuously refined and new physicochemical properties are generated. However, its mechanism for improving the taste of natto and the efficacy of nattokinase still needs further research. Summary of the Invention

[0005] The purpose of this invention is to provide a nattokinase powder based on ultrafine natto pulverization, its preparation method, and its application. The increased specific surface area exposes surface active groups, enhancing adsorption and solubility, improving the palatability of the beverage, further increasing the absorption rate of nattokinase after consumption, and ensuring that the product is rich in protein and other nutrients without loss, exhibiting good product stability and a long shelf life.

[0006] To achieve the above objectives, the present invention provides a method for preparing nattokinase powder based on ultrafine natto pulverization, comprising the following steps:

[0007] S1. Pretreatment: Mix natto with the preservative according to the ratio, stir for 8-12 minutes, spread it evenly in a container and pre-freeze for 2-24 hours to obtain pretreated natto. Adding the preservative before the freeze-drying stage can encapsulate enzyme molecules, protect their activity, optimize their structure, and form hydrogen bonds with nattokinase in natto. During pre-freezing, a glassy matrix is ​​formed, which lowers the freezing point and inhibits ice crystal growth, preventing nattokinase from being inactivated during ice crystal formation.

[0008] S2, freeze drying: The natto obtained in S1 is transferred to a freeze dryer and subjected to atmospheric pressure cooling, vacuum heating and atmospheric pressure heating in sequence to obtain freeze-dried natto;

[0009] S3. Coarse grinding: According to the ratio, transfer the anti-caking agent and the freeze-dried natto obtained in S2 to a grinder. After grinding and passing through an 80-100 mesh sieve, coarse natto powder is obtained. The addition of anti-caking agent takes into account both activity retention and powder performance. It reduces protein exposure through inclusion and reduces the adhesion of the powder after freeze-drying. Coarse grinding increases the specific surface area and further exposes the surface active groups.

[0010] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill, pulverized, passed through a 200-5000 mesh sieve, and packaged to obtain nattokinase powder.

[0011] Preferably, in S1, the natto is fresh natto with a nattokinase content of 1000 FU / g or higher on a dry basis and a live bacteria count of ≥1 billion / g or higher.

[0012] Preferably, in S1, the mass ratio of the natto to the preservative is 10:1 to 2;

[0013] The protective agent is one or more of trehalose, mannitol, or maltodextrin.

[0014] Preferably, in S1, the thickness of the paving is 1 to 2 cm.

[0015] Preferably, in S2, the atmospheric pressure cooling, vacuum heating, and atmospheric pressure heating processes specifically involve:

[0016] First, the initial temperature of the freeze dryer is set to -40 to -30°C. The natto obtained in S1 is transferred to the freeze dryer and kept at the set temperature for 2.5 to 6 hours to ensure that the natto is completely frozen and forms a stable ice crystal structure. Then, the vacuum degree is set to 10 to 30 Pa, and the temperature is raised to 20 to 30°C at a rate of 5 to 10°C / min. After reaching the set temperature, it is kept at the set temperature for 6 to 10 hours for sublimation drying, so that the ice crystals in the natto are directly sublimated into water vapor and discharged. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is raised to 35 to 40°C at a rate of 1 to 5°C / min. After reaching the set temperature, it is kept at the set temperature for 4 to 6 hours for desorption drying, further removing the residual bound water in the natto and reducing the moisture content of the natto to below 3%.

[0017] Preferably, in step S3, the mass ratio of the freeze-dried natto to the anti-caking agent is 100:0.5-2;

[0018] The anti-caking agent is β-cyclodextrin.

[0019] Preferably, in step S3, the anti-caking agent and the freeze-dried natto obtained in step S2 are mixed evenly and then transferred to a grinder. The speed is set to 5000-8000 rpm, and the mixture is ground for 1 minute followed by a 2-minute interval. This process is repeated 2-3 times.

[0020] Preferably, in step S4, the coarse natto powder obtained in step S3 is transferred to an air jet mill, and the milling temperature is set to 0-10℃, the air pressure to 0.8-1.0MPa, the rotation speed to 8000-12000 rpm, and the milling time to 10-40 min, to ensure that the material is fully dispersed in the milling chamber.

[0021] The present invention also provides a nattokinase powder based on ultrafine natto powder, wherein the nattokinase content of the nattokinase powder is greater than 1000 FU / g and the vitamin K content of the nattokinase powder is greater than 12 μg / g.

[0022] The present invention also provides a nattokinase powder based on ultrafine natto powder for use in beverages, wherein the amount of nattokinase powder added is 2-30% of the total mass.

[0023] Therefore, the present invention employs the above-mentioned nattokinase powder based on ultrafine natto pulverization, its preparation method, and its application, with the following beneficial effects:

[0024] This invention utilizes ultrafine pulverization technology to alter the physicochemical properties of natto, increasing its specific surface area and exposing surface-active groups. This enhances its adsorption and solubility, preventing clumping when mixed with drinking water, and reducing the fermented taste and eliminating its sticky texture. Furthermore, the nutritional components are not destroyed; the levels of nattokinase and vitamin K are well preserved. The absorption rate of nattokinase in beverages prepared from nattokinase powder is significantly higher than that of directly consuming natto, resulting in superior taste and nutritional value.

[0025] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0026] The technical solution of the present invention will be further described below through embodiments.

[0027] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0028] The experimental materials were fresh natto purchased from the same brand at the same time.

[0029] Unless otherwise specified, all other experimental materials and instruments used in this invention are conventional experimental materials in the field and can be purchased through commercial channels.

[0030] Example 1

[0031] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0032] S1. Pretreatment: Take 1kg of natto, transfer it to a clean and dry container, add 100g of trehalose and mix, stir for 10 minutes to fully activate nattokinase, spread it evenly on a dry bottle, control the thickness to 2cm, and pre-freeze it overnight at -40℃ to obtain pretreated natto.

[0033] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0034] S3. Coarse grinding: Transfer 8g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0035] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill. The grinding temperature of the air jet mill is set to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 10min. After passing through a 500-mesh sieve, the powder is packaged to obtain nattokinase powder, weighing 337.5g.

[0036] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0037] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0038] Example 2

[0039] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0040] S1. Pretreatment: Take 1 kg of natto, transfer it to a clean and dry container, add 150 g of trehalose and mix, stir for 10 min to fully activate nattokinase, spread it evenly on a dry bottle, control the thickness to 2 cm, and pre-freeze it overnight at -40℃ to obtain pretreated natto.

[0041] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0042] S3. Coarse grinding: Transfer 8g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0043] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill. The grinding temperature of the air jet mill is set to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 10min. After passing through a 500-mesh sieve, the powder is packaged to obtain nattokinase powder, weighing 377.0g.

[0044] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0045] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0046] Example 3

[0047] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0048] S1. Pretreatment: Take 1 kg of natto, transfer it to a clean and dry container, add 150 g of trehalose and mix, stir for 10 min to fully activate nattokinase, spread it evenly on a dry bottle, control the thickness to 2 cm, and pre-freeze it overnight at -40℃ to obtain pretreated natto.

[0049] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0050] S3. Coarse grinding: Transfer 10g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0051] S4. Ultrafine grinding: Transfer the coarse natto powder obtained in S3 to an air jet mill. Set the grinding temperature of the air jet mill to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 10min. Pass the powder through a 500-mesh sieve and package it to obtain nattokinase powder, weighing 410.5g.

[0052] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0053] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0054] Example 4

[0055] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0056] S1. Pretreatment: Take 1 kg of natto, transfer it to a clean and dry container, add 150 g of trehalose and mix, stir for 10 min to fully activate nattokinase, spread it evenly on a dry bottle, control the thickness to 2 cm, and pre-freeze it overnight at -40℃ to obtain pretreated natto.

[0057] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0058] S3. Coarse grinding: Transfer 10g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0059] S4. Ultrafine grinding: Transfer the coarse natto powder obtained in S3 to an air jet mill. Set the grinding temperature of the air jet mill to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 20min. Pass the powder through a 1000-mesh sieve and package it to obtain nattokinase powder, weighing 377.5g.

[0060] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0061] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0062] Example 5

[0063] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0064] S1. Pretreatment: Take 1kg of natto, transfer it to a clean and dry container, add 130g of trehalose and 20g of maltodextrin, mix and stir for 10 minutes to fully activate nattokinase, spread it evenly on a drying bottle, control the thickness to 2cm, and pre-freeze overnight in a -40℃ refrigerator to obtain pretreated natto.

[0065] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0066] S3. Coarse grinding: Transfer 10g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0067] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill. The grinding temperature of the air jet mill is set to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 20min. After passing through a 1000-mesh sieve, the powder is packaged to obtain nattokinase powder, weighing 378.5g.

[0068] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0069] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0070] Example 6

[0071] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0072] S1. Pretreatment: Take 1 kg of natto, transfer it to a clean and dry container, add 130 g of trehalose and 20 g of mannitol, mix and stir for 10 minutes to fully activate nattokinase, spread it evenly on a dry bottle, control the thickness to 2 cm, and pre-freeze it overnight at -40℃ to obtain pretreated natto.

[0073] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0074] S3. Coarse grinding: Transfer 10g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0075] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill. The grinding temperature of the air jet mill is set to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 20min. After passing through a 1000-mesh sieve, the powder is packaged to obtain nattokinase powder, weighing 378.8g.

[0076] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0077] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0078] Example 7

[0079] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0080] S1. Pretreatment: Take 1 kg of natto, transfer it to a clean and dry container, add 130 g of trehalose, 10 g of maltodextrin and 10 g of mannitol, mix and stir for 10 min to fully activate natto kinase, spread it evenly on a drying bottle, control the thickness to 2 cm, and pre-freeze overnight in a -40℃ refrigerator to obtain pretreated natto.

[0081] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0082] S3. Coarse grinding: Transfer 10g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0083] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill. The grinding temperature of the air jet mill is set to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 20min. After passing through a 1000-mesh sieve, the powder is packaged to obtain nattokinase powder, weighing 378.5g.

[0084] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0085] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0086] Example 8

[0087] A nattokinase powder and beverage based on ultrafine natto grinding, the preparation method of which is as follows:

[0088] S1. Pretreatment: Take 1 kg of natto, transfer it to a clean and dry container, add 130 g of trehalose, 10 g of maltodextrin and 10 g of mannitol, mix and stir for 10 min to fully activate natto kinase, spread it evenly on a drying bottle, control the thickness to 2 cm, and pre-freeze overnight in a -40℃ refrigerator to obtain pretreated natto.

[0089] S2. Freeze-drying: First, the initial temperature of the freeze dryer is set to -35℃. The natto obtained in S1 is transferred to the freeze dryer, and a transparent drying drum and top cap are placed on top. After reaching the set temperature, the temperature is maintained for 2.5 hours. Then, the vacuum degree is set to 15Pa, and the temperature is increased to 30℃ at a rate of 5℃ / min. After reaching the set temperature, the temperature is maintained for 10 hours. Finally, the vacuum degree is set to atmospheric pressure, and the temperature is increased to 35℃ at a rate of 3℃ / min. After reaching the set temperature, the temperature is maintained for 4 hours to obtain freeze-dried natto.

[0090] S3. Coarse grinding: Transfer 8g of β-cyclodextrin and the freeze-dried natto obtained in S2 to a grinder. Set the grinder speed to 5000 rpm, grind for 1 minute, then pause for 2 minutes. Repeat 3 times, and pass through an 80-mesh sieve to obtain coarse natto powder.

[0091] S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill. The grinding temperature of the air jet mill is set to 5℃, the air pressure to 0.8MPa, the rotation speed to 10000 rpm, and the grinding time to 10min. After passing through a 500-mesh sieve, the powder is packaged to obtain nattokinase powder, weighing 378.8g.

[0092] In this embodiment, the packaging uses nitrogen-filled packaging (oxygen residue <1%), and is then refrigerated at 4°C to prevent nattokinase from oxidizing and becoming inactive. The shelf life is 6 months.

[0093] S5. Add 20g of nattokinase powder to 80ml of room temperature drinking water to obtain a beverage. The beverage is free of obvious lumps, the solution is uniform, and no stratification or precipitation occurs after standing for 5 minutes.

[0094] Comparative Example 1

[0095] A natto mixture is obtained by using 100g of fresh natto and 10ml of drinking water as raw materials and then crushing them at low temperature.

[0096] Test

[0097] 1. Particle size detection

[0098] The particle size of the nattokinase powders prepared in Examples 1 to 8 was measured using a laser particle size analyzer. The average particle size was 1-10 μm, the median particle size was 8-9 μm, and the particle size distribution was uniform.

[0099] 2. Moisture content detection

[0100] The moisture content of the nattokinase powder prepared in Examples 1 to 8 was determined by Karl Fischer method. The moisture content was controlled to be below 3%, which indicates that the product has good stability and is conducive to extending the shelf life.

[0101] 3. Active ingredient detection

[0102] The content of nattokinase in the beverages prepared in Examples 1-8 and Comparative Example 1 was detected by electrophoresis. The enzyme activity was estimated by comparing the band intensity with the standard. The results are shown in Table 1.

[0103] Table 1 Enzyme activity results

[0104] Enzyme activity (U / mg) Example 1 16.255 Example 2 17.001 Example 3 17.677 Example 4 18.680 Example 5 18.675 Example 6 24.335 Example 7 26.942 Example 8 26.500 Comparative Example 1 12.005

[0105] Table 1 shows that the nattokinase powders prepared in Examples 1 to 8 all exhibited good retention of nattokinase content. The addition of excipients (protectants and antagonists) mitigated the protein structure damage caused by drying and pulverizing steps. The simultaneous addition of protectants trehalose, maltodextrin, and mannitol allowed trehalose to directly bind to the enzyme, forming a stable matrix. Maltodextrin focused on protecting the matrix in a glassy state, reducing molecular motion, while mannitol focused on resisting osmotic pressure damage. These ingredients synergistically covered different stages of the freeze-drying process, and together with the antagonists, protected the spatial conformational integrity of nattokinase during drying and pulverizing, contributing to improved enzyme activity. Furthermore, according to the relevant parameter settings of the air jet mill, a higher mesh size in the ultrafine pulverization may lead to increased viscosity. This viscosity difference may interfere with the partial denaturation of nattokinase in natto, indirectly causing a decrease in activity. Therefore, it was necessary to increase the amount of antagonist added accordingly to maintain enzyme activity.

[0106] The vitamin K2 content in the beverages prepared in Examples 1-8 and Comparative Example 1 was determined by liquid chromatography-mass spectrometry (LC-MS / MS), and the results are shown in Table 2.

[0107] Table 2 Results of Vitamin K

[0108] <![CDATA[Vitamin K2 (μg / 100g)]]> Example 1 122.79 Example 2 125.12 Example 3 123.68 Example 4 125.19 Example 5 124.35 Example 6 124.56 Example 7 124.55 Example 8 124.14 Comparative Example 1 126.04

[0109] As shown in Table 2, the vitamin K content of the nattokinase powder prepared in Examples 1 to 8 is well retained.

[0110] 4. In vivo absorption rate test

[0111] The absorption rate of nattokinase in the beverages prepared in Examples 1-8 and Comparative Example 1 was tested by simulating gastrointestinal digestion. The steps are as follows:

[0112] Gastric phase: Digested with hydrochloric acid (pH 1.2) + pepsin at 37°C for 30 min;

[0113] Intestinal phase: Digestion with phosphate buffer (pH 7.4) + pancreatic enzymes + bile salts for 2 hours to simulate the intestinal environment.

[0114] Transmembrane absorption simulation: The detection results using the Caco-2 cell monolayer model (the epithelial barrier formed by human colon cancer cell lines) are shown in Table 3.

[0115] Table 3 Absorption rate results

[0116] Absorption rate (times) Example 1 1.85 Example 2 2.01 Example 3 2.10 Example 4 1.55 Example 5 1.74 Example 6 1.78 Example 7 1.78 Example 8 1.75 Comparative Example 1 1

[0117] As shown in Table 3, the absorption rate of nattokinase in beverages prepared from nattokinase powder is significantly higher than that of directly consuming natto, reaching up to 2.10 times.

[0118] Therefore, the present invention adopts the above-mentioned nattokinase powder based on ultrafine natto pulverization, preparation method and application, which increases the specific surface area, exposes the surface active groups, enhances adsorption and solubility, improves the taste of the beverage, and further improves the absorption rate of nattokinase after consumption.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing nattokinase powder based on ultrafine natto pulverization, characterized in that, Includes the following steps: S1. Pretreatment: Mix natto with the preservative according to the ratio, stir, spread evenly in a container and pre-freeze for 2-24 hours to obtain pretreated natto. S2, freeze drying: The natto obtained in S1 is transferred to a freeze dryer and subjected to atmospheric pressure cooling, vacuum heating and atmospheric pressure heating in sequence to obtain freeze-dried natto; S3. Coarse grinding: According to the proportion, transfer the anti-caking agent and the freeze-dried natto obtained in S2 to a grinder, grind it, and pass it through an 80-100 mesh sieve to obtain coarse natto powder; S4. Ultrafine grinding: The coarse natto powder obtained in S3 is transferred to an air jet mill, pulverized, passed through a 200-5000 mesh sieve, and packaged to obtain nattokinase powder.

2. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In S1, the natto is fresh natto with a nattokinase content of ≥1000FU / g on a dry basis and a live bacteria count of ≥1 billion / g.

3. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In S1, the mass ratio of the natto to the protective agent is 10:1 to 2; The protective agent is one or more of trehalose, mannitol, or maltodextrin.

4. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In S1, the thickness of the paving is 1 to 2 cm.

5. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In S2, the atmospheric pressure cooling, vacuum heating, and atmospheric pressure heating processes are specifically as follows: First, the initial temperature of the freeze dryer is set to -40 to -30℃. The natto obtained in S1 is transferred to the freeze dryer and kept at the set temperature for 2.5 to 6 hours. Then, the vacuum degree is set to 10 to 30 Pa, the temperature is increased to 20 to 30℃ at a rate of 5 to 10℃ / min, and kept at the set temperature for 6 to 10 hours. Finally, the vacuum degree is set to atmospheric pressure, the temperature is increased to 35 to 40℃ at a rate of 1 to 5℃ / min, and kept at the set temperature for 4 to 6 hours.

6. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In S3, the mass ratio of the freeze-dried natto to the anti-caking agent is 100:0.5-2; The anti-caking agent is β-cyclodextrin.

7. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In step S3, the anti-caking agent and the freeze-dried natto obtained in step S2 are mixed evenly and then transferred to a grinder. The speed is set to 5000-8000 rpm. After grinding for 1 minute, the mixture is paused for 2 minutes. This process is repeated 2-3 times.

8. The method for preparing nattokinase powder based on ultrafine natto pulverization according to claim 1, characterized in that, In step S4, the coarse natto powder obtained in step S3 is transferred to an air jet mill. The milling temperature is set to 0–10℃, the air pressure to 0.8–1.0 MPa, the rotation speed to 8000–12000 rpm, and the milling time to 10–40 min.

9. A nattokinase powder prepared by the method for preparing nattokinase powder based on ultrafine natto pulverization according to any one of claims 1-8, characterized in that, The nattokinase powder contains more than 1000 FU / g of nattokinase and more than 12 μg / g of vitamin K.

10. The application of natto kinase powder based on ultrafine natto powder as described in claim 9 in beverages, characterized in that, The amount of nattokinase powder added is 2-30% of the total mass.