Method for efficiently preparing bovine colostrum freeze-dried powder

Abstract

The invention discloses a method for efficiently preparing bovine coloctrum freeze-dried powder, and belongs to the technical field of bovine coloctrum processing. According to the preparation method of the bovine colostrum freeze-dried powder disclosed by the invention, a set of bovine colostrum powder preparation technology capable of efficiently retaining active components and improving the product quality is constructed through innovative processes such as multi-stage membrane filtration, lactic acid bacteria precise fermentation, nanofiltration concentration, functional agglomeration granulation and the like; therefore, the core problems of loss of active ingredients, low desugaring efficiency, poor powder reconstituability and the like in the prior art are precisely solved.

Description

Technical Field

[0001] The invention relates to a method for efficiently preparing bovine colostrum freeze-dried powder, and belongs to the technical field of bovine colostrum processing. Background Art

[0002] Bovine colostrum, the milk secreted by cows 3-7 days after giving birth, is rich in bioactive ingredients such as immunoglobulins and lactoferrin, making it a highly promising functional food ingredient. However, existing colostrum powder preparation processes face significant technical bottlenecks, such as loss of active ingredients, low sugar removal efficiency, and poor powder dissolution, limiting its industrial application.

[0003] Traditional colostrum sterilization and degreasing relies on centrifugation or conventional filtration. While centrifugation can partially remove fat, high-speed centrifugation can easily rupture fat globules, releasing lipase that degrades milk fat. Mechanical shear forces also disrupt the spatial structure of immunoglobulins, resulting in only 60%-70% IgG activity retention. Conventional filtration retains less than 70% of bacteria smaller than 1μm in diameter, such as E. coli, and is ineffective in removing colloidal fat particles, increasing the risk of excessive microbial counts in the product. Furthermore, residual fat can accelerate oxidative deterioration.

[0004] Furthermore, traditional chemical desugaring methods are complex, costly, and prone to introducing chemical residues. Furthermore, the desugaring rate for single-strain fermentation is typically less than 70%, which cannot meet the needs of people with lactose intolerance. Furthermore, traditional concentration processes such as thermal evaporation can denature immunoglobulins when increasing solids content, resulting in an activity retention rate of only 50%-60%. The spray drying technology used in the drying process exacerbates the degradation of active ingredients due to high temperatures, and the resulting powder is fine, has poor dissolution properties, and is prone to agglomeration upon rehydration.

[0005] Colostrum powder produced using existing processes also suffers from low production efficiency and poor nutritional value retention. Small molecule impurities, such as free amino acids, are not effectively removed, impacting product functionality. The agglomeration granulation process lacks targeted design, resulting in poor dispersion of powder particles and a rehydration time of 2-3 minutes, making it difficult to meet instant dissolution requirements. Therefore, how to efficiently sterilize, degrease, and remove sugars while retaining active ingredients and optimizing the powder's physical properties remains a pressing technical challenge in colostrum processing. Summary of the Invention

[0006] In response to the defects and shortcomings of existing technologies, the present invention proposes an innovative process for efficiently preparing bovine colostrum freeze-dried powder. This process uses a multi-stage membrane filtration system with successively smaller pore sizes to achieve efficient sterilization and degreasing, with a bacterial removal rate exceeding 99.9% and an immunoglobulin retention rate exceeding 95%. A 1:1 ratio of Streptococcus thermophilus and Lactobacillus plantarum DY6 is selected for fermentation and desugaring, resulting in a lactose removal rate exceeding 95%. The short-chain fatty acids and vitamins produced during the fermentation process also enhance the health benefits of the product. The innovative introduction of a nanofiltration concentration step reduces the freeze-drying load while effectively retaining active ingredients in the colostrum, such as small-molecule amino acids and growth factors. A composite spray solution of egg yolk lecithin, distarch phosphate, and dextran syrup is used in the agglomeration and granulation stage to reduce the powder particle size to 50-100 μm and shorten the dissolution time to less than 10 seconds. The present invention aims to construct a set of bovine colostrum powder preparation technologies that can efficiently retain active ingredients and improve product quality through innovative processes such as multi-stage membrane filtration, precise fermentation of lactic acid bacteria, nanofiltration concentration, and functional agglomeration granulation, thereby accurately solving core problems in existing processes such as active ingredient loss, low desugaring efficiency, and poor powder dissolution properties.

[0007] In order to achieve the above objectives, the technical solutions provided are as follows:

[0008] A first object of the present invention is to provide a method for efficiently preparing bovine colostrum powder, the method comprising the following steps:

[0009] (1) Raw material collection and pretreatment

[0010] The collected bovine colostrum is filtered to remove large impurities and foreign matter;

[0011] (2) Multi-stage membrane filtration, sterilization and degreasing

[0012] The pretreated bovine colostrum is sequentially passed through membrane filtration units with pore sizes of 0.4 to 0.6 μm and 0.1 to 0.2 μm to obtain a clarified bovine colostrum filtrate;

[0013] (3) Lactic acid bacteria fermentation and desugaring

[0014] The lactic acid bacteria are inoculated into the desinfected and defatted bovine colostrum filtrate and fermented at 35-42°C for 12-24 hours; wherein the lactic acid bacteria are thermophilic Streptococcus and plantarum Lactobacillus DY6, and the ratio of the bacteria is 1:1-2:1;

[0015] (4) Nanofiltration concentration

[0016] The fermented bovine colostrum is concentrated by nanofiltration at a pressure of 1.5 to 2.5 MPa and a concentration multiple of 3 to 5 times;

[0017] (5) Freeze-drying

[0018] The concentrated bovine colostrum liquid is freeze-dried to obtain highly active bovine colostrum freeze-dried powder;

[0019] (6) Agglomeration granulation

[0020] A dry powder fluidized bed mixer with a spraying device was used to agglomerate and granulate the bovine colostrum freeze-dried powder;

[0021] (7) Vacuum drying

[0022] The colostrum powder particles that have undergone agglomeration and granulation are placed in a vacuum drying oven for drying, and then packaged to obtain the bovine colostrum powder product.

[0023] In one embodiment, the bovine colostrum in step (1) is bovine colostrum produced 3 to 7 days after delivery.

[0024] In one embodiment, the mesh size of the filtration sieve in step (1) is 10 to 20 meshes.

[0025] In one embodiment, the multi-stage membrane filtration in step (2) can efficiently remove bacteria and fat in bovine colostrum while retaining active ingredients in bovine colostrum, such as immunoglobulins, lactoferrin, etc.

[0026] In one embodiment, the lactic acid bacteria inoculation volume ratio in step (3) is 1-2%, and the seed solution concentration is 10 billion CFU / g.

[0027] In one embodiment, during the lactic acid bacteria fermentation process in step (3), the lactic acid bacteria metabolize the lactose in the colostrum into lactic acid, thereby reducing the lactose content and improving the taste and nutritional value of the product. Furthermore, the lactic acid bacteria fermentation also produces beneficial metabolites, such as short-chain fatty acids and vitamins, which enhance the health benefits of the product. The lactose can be efficiently removed, with a desugaring rate exceeding 90%, while ensuring that the active ingredients in the colostrum are not lost.

[0028] In one embodiment, the molecular weight of the nanofiltration membrane used in the nanofiltration concentration in step (4) is 100 to 250 Da; nanofiltration concentration can further increase the solid content of the bovine colostrum, reduce the load of subsequent freeze-drying, and remove some small molecular impurities to further purify the product.

[0029] In one embodiment, the freeze-drying conditions of step (5) are: first freezing at -60 to -40°C for 4 to 6 hours, and then freeze-drying under the conditions of a vacuum degree of 10 to 30 Pa and a temperature of -25 to -15°C; the freeze-drying process can retain the active ingredients and nutrients in the bovine colostrum to the greatest extent, thereby extending the shelf life of the product.

[0030] In one embodiment, the agglomeration granulation in step (6) is specifically performed by using a dry powder fluidized bed mixing device with a spraying device to agglomerate and granulate the bovine colostrum freeze-dried powder, and the spraying liquid contains 0.05-0.15% egg yolk lecithin, 0.03-0.05% distarch phosphate, and 0.02-0.04% glucan syrup based on the dry matter content. The mass of egg yolk lecithin, distarch phosphate and dextran syrup to be added is calculated according to the mass of the colostrum powder to be processed, and after being combined, it is configured into a spray liquid with a total solid content of 1.5% to 2% for powder surface spraying. During the spraying process, the temperature of the internal cavity of the mixing device is maintained at 40 to 55°C, continuously drying the surface moisture, keeping the material dry, and increasing the viscosity of the liquid attached to the surface and the viscosity. The spray liquid prepared in this way is characterized by good adhesion and strong hydration ability. While ensuring the formation of large-particle powder, it ensures rapid wetting, swelling, diffusion and depolymerization after rehydration, thereby giving the bovine colostrum freeze-dried powder good solubility.

[0031] The second object of the present invention is to provide bovine colostrum powder obtained by the above method.

[0032] In one embodiment, the bovine colostrum powder can be used as an immunity-enhancing health product for the elderly and children, and can also be used as a high-quality protein supplement food for postoperative patients.

[0033] The third object of the present invention is to provide a use of the bovine colostrum powder described above in preparing functional foods.

[0034] Beneficial effects:

[0035] Compared with the prior art, the bovine colostrum powder processing technology of the present invention has significant advantages, which are mainly reflected in the following aspects:

[0036] (1) Multi-stage membrane filtration for sterilization and degreasing: The multi-stage membrane filtration unit with decreasing pore size can effectively remove bacteria, fat particles and other impurities in the colostrum, achieving efficient sterilization and degreasing effects, while retaining the active ingredients in the colostrum to the greatest extent, providing pure raw materials for subsequent processing steps;

[0037] (2) Desugaring by lactic acid bacteria fermentation: By selecting specific lactic acid bacteria strains and optimizing fermentation conditions, the lactose content is significantly reduced, with a desugaring rate of over 95%. This technology not only improves the taste of the product and reduces the discomfort of people with lactose intolerance, but also produces beneficial metabolites such as short-chain fatty acids and vitamins due to the metabolic action of lactic acid bacteria, thereby enhancing the nutritional value and health function of the product. Compared with traditional desugaring methods, it has significant advantages such as high desugaring efficiency, mild operating conditions, and good protection of active ingredients.

[0038] (3) Nanofiltration concentration: After fermentation and desugaring, a nanofiltration concentration step is introduced, and a nanofiltration membrane with a suitable molecular weight cutoff is selected to perform concentration under a specific operating pressure. This step effectively increases the solid content of the colostrum, reduces the energy consumption and time cost of freeze-drying, and further removes small molecule impurities, thereby improving the purity of the product. Nanofiltration concentration is organically combined with multi-stage membrane filtration and lactic acid bacteria fermentation technology to construct a set of efficient and synergistic bovine colostrum deep processing technology, which provides a strong guarantee for the preparation of high-quality, highly active bovine colostrum freeze-dried powder.

[0039] (4) Agglomeration granulation: The main creativity of this process lies in the design of the spray liquid formula. The spray liquid is characterized by good adhesion and strong hydration ability. While ensuring the formation of large particle powder, it also ensures rapid water wetting, swelling, diffusion and deagglomeration after rehydration, thereby giving the bovine colostrum freeze-dried powder good dissolution properties;

[0040] The high-activity bovine colostrum freeze-dried powder of the present invention can be widely used in the fields of health care products, food, medicine, etc., and has broad application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The data graph of fat removal rate and sugar removal rate of bovine colostrum powder obtained for the examples and comparative examples;

[0042] Figure 2 The data graph of the content of epidermal growth factor and taurine in bovine colostrum powder obtained for the examples and comparative examples. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. The following specific embodiments further describe the present invention.

[0044] The testing method of the present invention

[0045] 1. Total bacterial count

[0046] The test method for the total colony count in bovine colostrum powder usually adopts the plate colony count method.

[0047] First, accurately weigh a certain amount of bovine colostrum powder sample and add an appropriate amount of sterile physiological saline or other suitable diluent to fully dissolve and prepare a uniform sample solution. Then, the sample solution is gradient diluted, usually with a dilution factor of 10 times, 100 times, etc., to obtain dilutions of different concentrations. Next, take an appropriate amount of the dilution solution and inoculate it onto a plate culture medium. Using the pour plate method, the bacterial solution is evenly distributed on the surface of the culture medium. The plate is placed under suitable temperature and humidity conditions for incubation. The bacterial culture temperature is 37°C and the incubation time is 48 hours. After the incubation is completed, the morphology and number of colonies on the plate are observed, and plates with a colony count between 30 and 300 are selected for counting. Finally, the total colony count in the bovine colostrum powder sample is calculated based on the number of colonies and the dilution factor.

[0048] 2. Degreasing rate

[0049] The fat content in the product was tested by Soxhlet extraction and the fat removal rate was calculated.

[0050] First, accurately weigh a certain amount of bovine colostrum powder sample, place it in a filter paper tube, and place it in the extraction tube of a Soxhlet extractor; then, add an appropriate amount of anhydrous ether or petroleum ether or other organic solvents to the extractor, which can dissolve fat components; by heating and refluxing, the solvent is continuously circulated to extract the fat in the bovine colostrum powder and dissolve it in the solvent. The extraction process usually lasts for several hours until the extract is clear and transparent, indicating that the fat has been basically extracted; then, the extract is recovered and the solvent is evaporated to obtain a fat residue; finally, the mass of the extracted fat is weighed, and the fat content in the bovine colostrum powder is calculated based on the original mass of the sample, and the fat removal rate is calculated.

[0051] 3. Sugar removal rate

[0052] Accurately weigh approximately 0.1-0.5g of milk powder sample into a 100mL volumetric flask. Add an appropriate amount of anhydrous ethanol and shake to disperse. Then, dilute to volume with sodium acetate-acetic acid buffer, shake well, and let stand to obtain the sample solution. Prepare the lactase solution, glucose oxidase solution, and p-hydroxybenzoic acid solution, and store at approximately 4°C until needed. Place 2mL of the sample solution into two test tubes. Add 0.2mL of lactase solution to one test tube as a reaction tube, and an equal volume of phosphate buffer to the other test tube as a blank control. Incubate in a 37°C waterbath for 30-60 minutes, then terminate the enzyme reaction in a boiling water bath. After cooling, add an appropriate amount of p-hydroxybenzoic acid solution and glucose oxidase solution to each test tube, and incubate in a 37°C waterbath for another 10-15 minutes. Measure the absorbance of the reaction tubes using a spectrophotometer at the specified wavelength. Simultaneously, prepare a series of lactose standard solutions of known concentrations. Following the same color development procedure, measure the absorbance and plot a standard curve. Finally, the lactose content in the milk powder is calculated based on the sample solution absorbance and the standard curve, combined with the sample solution dilution factor and sample weight. The lactose content before and after desugaring is calculated, and the percentage of lactose reduced is calculated as the desugaring rate.

[0053] 4. Epidermal Growth Factor EGF quantitative test

[0054] The quantitative test of EGF is usually performed by enzyme-linked immunosorbent assay (ELISA), which uses specific antibodies to bind to EGF, and calculates the EGF content by enzyme labeling technology and measuring the light absorption value of the enzyme reaction with a photometer.

[0055] The specific steps include:

[0056] (1) Sample preparation: The bovine colostrum sample was prepared into a solution of appropriate concentration using physiological saline and then centrifuged to remove impurities.

[0057] (2) Sample addition and incubation: Add the standard or sample to the wells of the ELISA plate and incubate at 37°C for a certain period of time.

[0058] (3) Washing and antibody binding: Add biotinylated antibody, incubate and then wash; then add enzyme conjugate and continue incubation.

[0059] (4) Color development and termination: Add the color developer TMB, add the stop solution after incubation to terminate the reaction.

[0060] (5) Reading and calculation: Measure the OD value at a wavelength of 450 nm using a microplate reader, and calculate the concentration of EGF in the sample using the standard curve.

[0061] 5. Taurine quantitative test

[0062] The program injection-pre-column derivatization-high performance liquid chromatography (HPLC) method was used, and the specific steps were as follows:

[0063] (1) Sample pretreatment: After the bovine colostrum sample is dissolved, it is derivatized before column derivatization using a derivatization reagent.

[0064] (2) Sampling and separation: Separation was performed using a high performance liquid chromatography system, and taurine was quantified based on its retention time and peak area.

[0065] (3) Data analysis: The data were recorded by the chromatography workstation and the taurine content in the sample was calculated based on the standard curve.

[0066] 6. Dispersibility

[0067] Add 20 mL of 25°C distilled water to a 50 mL beaker and stir at 700 rpm on a magnetic stirrer. Weigh 1 g of sample and quickly pour it into the beaker. Immediately begin recording the time it takes for the egg white powder to completely disperse in the water (no visible particles). A shorter dispersion time indicates a faster dispersion rate.

[0068] Example 1

[0069] A method for preparing highly active bovine colostrum freeze-dried powder comprises the following steps:

[0070] (1) Raw material collection and pretreatment

[0071] Select bovine colostrum within 3 days after delivery and filter it through a 20-mesh sieve to remove large impurities and foreign matter;

[0072] (2) Multi-stage membrane filtration, sterilization and degreasing

[0073] The pretreated bovine colostrum is sequentially passed through membrane filtration units with pore sizes of 0.45 μm and 0.1 μm to remove bacteria, fat particles and other impurities to obtain a clarified bovine colostrum filtrate;

[0074] (3) Lactic acid bacteria fermentation and desugaring

[0075] The lactic acid bacteria were inoculated into the decontaminated and defatted colostrum filtrate at a volume ratio of 2% (the concentration of the bacterial seed solution was 10 billion CFU / g), and fermented at 35°C for 24 hours. The lactic acid bacteria were Streptococcus thermophilus and Lactobacillus plantarum DY6, with a strain ratio of 1:1.

[0076] (4) Nanofiltration concentration

[0077] The fermented bovine colostrum was concentrated by nanofiltration using a nanofiltration membrane with a molecular weight cut-off of 220 Da and an operating pressure of 2.5 MPa, with a concentration multiple of 5.

[0078] (5) Freeze-drying

[0079] The concentrated bovine colostrum liquid was frozen at -40°C for 6 hours, and then freeze-dried under the conditions of a vacuum degree of 30 Pa and a temperature of -25°C to obtain a highly active bovine colostrum freeze-dried powder;

[0080] (6) Agglomeration granulation

[0081] A dry powder fluidized bed mixer with a spraying device is used to agglomerate and granulate the freeze-dried bovine colostrum powder. The spraying liquid contains 0.15% egg yolk lecithin, 0.05% distarch phosphate, and 0.04% dextran syrup, based on the dry matter content. The weight of the adhesive and dispersant to be added is calculated based on the mass of the colostrum powder to be processed. After confluence, the mixture is prepared into a spray liquid with a total solids content of 2%, and the powder surface is sprayed. During the spraying process, the temperature of the internal cavity of the mixer is maintained at 40-55°C to continuously dry out surface moisture, keep the material dry, and increase the viscosity and adhesion of the liquid attached to the surface.

[0082] (7) Vacuum drying

[0083] The agglomerated and granulated colostrum powder particles are placed in a vacuum drying oven for drying to obtain bovine colostrum powder with a relatively large particle size, which is then packaged into the final product.

[0084] Comparative Example 1

[0085] The only difference from Example 1 is that in step (2), the pretreated bovine colostrum is filtered only through a membrane filtration unit with a pore size of 0.45 μm to remove bacteria, fat particles and other impurities to obtain a clarified bovine colostrum filtrate; other parameters and conditions are the same as in Example 1.

[0086] Comparative Example 2

[0087] The only difference from Example 1 is that in step (3), the lactic acid bacteria are Lactobacillus bulgaricus and Lactobacillus plantarum DY6, and the strain ratio is 1:1; other parameters and conditions are the same as those in Example 1.

[0088] Comparative Example 3

[0089] The only difference from Example 1 is that the nanofiltration membrane in step (4) is replaced with a nanofiltration membrane with a molecular weight cutoff of 500 Da, and the other parameters and conditions are the same as those in Example 1.

[0090] Comparative Example 4

[0091] The only difference from Example 1 is that step (6) agglomeration and granulation is deleted.

[0092] Comparative Example 5

[0093] The only difference from Example 1 is that in step (6) the agglomeration and granulation process only 0.15% egg yolk lecithin is used for agglomeration and granulation; other parameters and conditions are the same as those in Example 1.

[0094] Result Analysis

[0095] Table 1. Properties of bovine colostrum powder obtained in Examples and Comparative Examples

[0096]

[0097] From Table 1 and Figures 1-2 From the results in the experiment, it can be seen that the technical solution of the present invention can achieve a sugar removal rate of more than 95%, a fat removal rate of more than 99%, a high sterilization rate, and the total bacterial count in the final powder is controlled within 200 CFU / g. In addition, small molecules such as epidermal growth factor EGF and taurine are well retained, and the overall dispersibility of the final product is also good.

[0098] Comparative Example 1 differs from Example 1 in that only a single filtration step using a 0.45-μm membrane filtration unit was used. This resulted in a higher number of bacteria and small-sized lipid micelles permeating the membrane, resulting in a lower overall sterilization effect and degreasing rate. This demonstrates that the multi-stage membrane filtration sterilization and degreasing proposed in the present invention can effectively achieve both sterilization and degreasing efficiency.

[0099] Comparative Example 2 uses Lactobacillus bulgaricus and Lactobacillus plantarum DY6 for fermentation and desugaring. The sugar metabolism rate of the Lactobacillus bulgaricus used is relatively slow. Under the same bacterial inoculation amount and fermentation conditions, the desugaring rate decreases. This also illustrates that the use of the two lactic acid bacteria in the present invention has a promoting effect on lactose metabolism and is effective in improving the efficiency of lactose removal in bovine colostrum.

[0100] Comparative Example 3 uses a nanofiltration concentration membrane with a higher molecular weight cutoff. Under this condition, the main protein components in bovine colostrum can also be concentrated, but the permeability of small molecule compounds such as epidermal growth factor EGF and taurine will increase, thereby resulting in a decrease in the content of small molecule active ingredients in the obtained product, affecting the functional quality of the final product.

[0101] The difference between Comparative Examples 4 and 5 and Example 1 is that the agglomeration granulation is not performed using the egg yolk lecithin, distarch phosphate, and glucan slurry co-agglomeration method proposed by the present invention. As a result, the final product has poor dispersibility due to the powder being too fine or the surface hydrophilicity being low, and requires stirring for a long time to be completely dispersed. This shows that the egg yolk lecithin, distarch phosphate, and glucan slurry co-agglomeration method designed by the present invention can effectively improve the dispersibility of bovine colostrum powder. The hydrophilicity of lecithin can help glucan slurry to better adsorb on the surface of bovine colostrum powder particles, and the charge regulation effect of distarch phosphate can enhance the stability of the entire system, making the particles more uniform during the dispersion process, while glucan slurry controls the movement of the particles by increasing the viscosity of the system and forming a network structure. This optimization of dynamic balance enables the bovine colostrum powder particles to always maintain a good dispersed state during the dispersion process, thereby significantly improving the dispersibility of bovine colostrum powder.

[0102] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for efficiently preparing bovine colostrum powder, characterized in that: The method comprises the following steps: (1) Raw material collection and pretreatment The collected bovine colostrum is filtered to remove large impurities and foreign matter; (2) Multi-stage membrane filtration, sterilization and degreasing The pretreated bovine colostrum is sequentially passed through membrane filtration units with pore sizes of 0.4 to 0.6 μm and 0.1 to 0.2 μm to obtain a clarified bovine colostrum filtrate; (3) Lactic acid bacteria fermentation and desugaring The lactic acid bacteria are inoculated into the desinfected and defatted bovine colostrum filtrate and fermented at 35-42°C for 12-24 hours; wherein the lactic acid bacteria are thermophilic Streptococcus and plantarum Lactobacillus DY6, and the ratio of the bacteria is 1:1-2:1; (4) Nanofiltration concentration The fermented bovine colostrum is concentrated by nanofiltration at a pressure of 1.5 to 2.5 MPa and a concentration multiple of 3 to 5 times; (5) Freeze-drying The concentrated bovine colostrum liquid is freeze-dried to obtain highly active bovine colostrum freeze-dried powder; (6) Agglomeration granulation A dry powder fluidized bed mixer with a spraying device was used to agglomerate and granulate the bovine colostrum freeze-dried powder; (7) Vacuum drying The colostrum powder particles that have undergone agglomeration and granulation are placed in a vacuum drying oven for drying, and then packaged to obtain the bovine colostrum powder product.

2. The method according to claim 1, characterized in that The bovine colostrum in step (1) is the bovine colostrum produced 3 to 7 days after birth.

3. The method according to claim 1, characterized in that The mesh number of the filtration screen in step (1) is 10 to 20 meshes.

4. The method according to claim 1, wherein The lactic acid bacteria inoculation volume ratio in step (3) is 1-2%, and the seed solution concentration is 10 billion CFU / g.

5. The method according to claim 1, wherein The molecular weight of the nanofiltration membrane used for nanofiltration concentration in step (4) is 100 to 250 Da.

6. The method according to claim 1, characterized in that The freeze-drying conditions of step (5) are: first freezing at -60 to -40°C for 4 to 6 hours, and then freeze-drying under the conditions of a vacuum degree of 10 to 30 Pa and a temperature of -25 to -15°C.

7. The method according to claim 1, characterized in that The agglomeration granulation in step (6) is specifically performed by using a dry powder fluidized bed mixing device with a spraying device to agglomerate and granulate the bovine colostrum freeze-dried powder, and the spraying liquid contains 0.05-0.15% egg yolk lecithin, 0.03-0.05% distarch phosphate, and 0.02-0.04% glucan syrup based on the dry matter content.

8. The method according to claim 7, characterized in that The specific spraying process is to calculate the mass of egg yolk lecithin, distarch phosphate and dextran slurry to be added according to the mass of the bovine colostrum powder to be processed, and then prepare a spray liquid with a total solid content of 1.5% to 2% for powder surface spraying. During the spraying process, the temperature of the internal cavity of the mixing device is maintained at 40 to 55 degrees Celsius, continuously drying the surface moisture to keep the material dry.

9. Bovine colostrum powder obtained by the method according to any one of claims 1 to 8.

10. Use of the bovine colostrum powder according to claim 9 in preparing functional foods.

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