Method for preparing bovine colostrum powder by adopting lactic acid bacteria fermentation desugaring and electrostatic spray drying processes

Abstract

The invention discloses a method for preparing bovine colostrum powder by adopting lactic acid bacteria fermentation desugaring and electrostatic spray drying processes, and belongs to the technical field of foods. The processing method of the bovine colostrum powder specifically comprises the following steps: quickly cooling collected bovine colostrum to 0-4 DEG C, and refrigerating and storing; the preparation method comprises the following steps: preparing bovine coloctrum, filtering and centrifuging the bovine coloctrum to remove a fat layer in milk so as to obtain degreased bovine coloctrum, sterilizing the degreased bovine coloctrum by adopting ceramic microfiltration equipment, and concentrating the sterilized bovine coloctrum by adopting a low-temperature vacuum concentration technology; and then fermenting and desugaring, carrying out electrostatic spray drying after desugaring, and finally cooling and packaging to obtain the bovine colostrum powder finished product. Compared with the bovine colostrum powder obtained by the traditional processing technology, the bovine colostrum powder has the advantages that the lactose content is lower, and the quality, flavor, stability and dispersity of the product are obviously improved.

Description

Technical Field

[0001] The invention relates to a method for preparing bovine colostrum powder by adopting lactic acid bacteria fermentation desugaring and electrostatic spray drying processes, and belongs to the technical field of food. Background Art

[0002] Bovine colostrum refers to the milk produced by dairy cows within seven days of calving. Rich in nutrients such as immunoglobulins, lactoferrin, growth factors, multiple vitamins, and minerals, it boasts numerous benefits, including boosting immunity and promoting growth and development. It is known as a "natural treasure trove of nutrition." In recent years, as people's awareness of health continues to grow, market demand for bovine colostrum powder, a functional dairy product, has shown rapid growth.

[0003] However, traditional colostrum powder processing has numerous shortcomings that severely limit its quality and market competitiveness. First, in terms of nutrient retention, traditional high-temperature sterilization and drying processes can easily denature or inactivate active ingredients in colostrum, such as immunoglobulins and lactoferrin. For example, traditional high-temperature sterilization temperatures are typically above 120°C and last for extended periods, which causes immunoglobulin activity in colostrum to drop by over 50%. Furthermore, the high temperatures and prolonged drying times of traditional spray drying processes can also lead to nutrient losses, particularly heat-sensitive ingredients such as vitamin C and B vitamins.

[0004] Secondly, in terms of product quality, colostrum powder produced using traditional methods suffers from issues such as poor taste and solubility. Due to a lack of effective homogenization, colostrum powder particles are large, prone to clumping and sedimentation after mixing, impacting the consumer experience. Furthermore, traditional methods fail to effectively control oxidation during the drying process, resulting in a darker product color and a poorer flavor, further reducing the product's market competitiveness.

[0005] Finally, regarding storage stability, colostrum powder produced using traditional methods, due to its inability to effectively isolate oxygen, is susceptible to oxidation and deterioration during storage, shortening the product's shelf life. For example, after three months of storage using traditional packaging methods, the oxidative rancidity rate of colostrum powder can reach as high as 30%, seriously impacting product quality and safety.

[0006] In summary, the traditional bovine colostrum powder processing technology has obvious deficiencies in nutrient retention, product quality and storage stability, and it is difficult to meet the market demand for high-quality bovine colostrum powder. Summary of the Invention

[0007] [Technical Issues]

[0008] Traditional bovine colostrum powder processing technology has obvious deficiencies in nutrient retention, product quality and storage stability, and it is difficult to meet the market demand for high-quality bovine colostrum powder.

[0009] [Technical solution]

[0010] In order to address the defects of the existing technology, the purpose of the present invention is to provide a method for preparing bovine colostrum powder by using lactic acid bacteria fermentation desugaring and electrostatic spray drying technology. This method maximizes the retention of nutrients, improves product quality and enhances storage stability through the rational design of the entire process, from strict control of raw material collection to refined and innovative operations in each link such as pretreatment, sterilization, concentration, desugaring, drying and packaging.

[0011] In order to achieve the above objectives, the technical solutions provided are as follows:

[0012] The first object of the present invention is to provide a method for preparing bovine colostrum powder by using lactic acid bacteria fermentation desugaring and electrostatic spray drying technology, the method comprising the following steps:

[0013] (1) Raw material pretreatment

[0014] The collected colostrum is quickly cooled to 0-4°C and refrigerated; it is then filtered and centrifuged to remove the fat layer in the milk to obtain skimmed colostrum;

[0015] (2) Microfiltration sterilization

[0016] The skimmed bovine colostrum in step (1) is sterilized using a ceramic microfiltration device, wherein the ceramic membrane used in the microfiltration has a pore size of 20 nm to 50 nm, and the permeate is collected;

[0017] (3) Concentration and desugaring

[0018] The permeate of step (2) is concentrated by low-temperature vacuum concentration technology to make the dry matter content of the bovine colostrum reach 20% to 30%; then the colostrum is fermented and desugared, and the concentrated colostrum is inoculated with Lactobacillus acidophilus (LA), Lactobacillus rhamnosus (LR), and Lactobacillus plantarum (LP) and calcium chloride is added as an auxiliary agent, and the fermentation temperature is 38-42° C. and the fermentation time is 5-10 hours;

[0019] (4) Drying

[0020] The fermented bovine colostrum is fed into an electrostatic spray drying tower, with the inlet air temperature controlled at 80°C to 110°C, the outlet air temperature controlled at 45°C to 60°C, the spray pressure maintained at a slightly negative pressure state of -10MPa to -20MPa, and a voltage applied to the atomizer port in the range of 10kV to 30kV;

[0021] (5) Cooling and packaging

[0022] The bovine colostrum powder dried in step (4) is cooled to a temperature below 30° C., and then sieved and nitrogen-filled and packaged to obtain the finished bovine colostrum powder.

[0023] In one embodiment, the bovine colostrum in step (1) is healthy and disease-free bovine colostrum produced within 3 days after calving, ensuring its high quality and rich nutritional ingredients.

[0024] In one embodiment, the filtering in step (1) refers to filtering the bovine colostrum to remove foreign matter such as impurities, blood clots, and milk skin.

[0025] In one embodiment, the centrifugal speed in step (1) is 5000-8000 rpm.

[0026] In one embodiment, the low-temperature vacuum concentration technology in step (3) is used for concentration at a temperature of 40° C. to 50° C., and a vacuum degree of 0.08 MPa to 0.09 MPa.

[0027] In one embodiment, the total inoculation amount of Lactobacillus acidophilus, Lactobacillus rhamnosus and Lactobacillus plantarum in step (3) is 1×10 7 ~5×10 8 CFU; the ratio of Lactobacillus acidophilus, Lactobacillus rhamnosus and Lactobacillus plantarum is 1:1:1.

[0028] In one embodiment, the concentration of calcium chloride in the fermentation system in step (3) is 20 to 40 mmol / L.

[0029] In one embodiment, the nitrogen filling amount of the nitrogen-filled package in step (5) is 10% to 15% of the package volume.

[0030] The second object of the present invention is to provide bovine colostrum powder obtained by the above-mentioned processing method.

[0031] 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.

[0032] The third object of the present invention is to provide a use of the bovine colostrum powder described above in preparing functional foods.

[0033] A fourth object of the present invention is to provide a method for improving the nutritional quality, stability and dispersibility of bovine colostrum powder, the method comprising the following steps:

[0034] (1) Raw material pretreatment

[0035] The collected colostrum is quickly cooled to 0-4°C and refrigerated; it is then filtered and centrifuged to remove the fat layer in the milk to obtain skimmed colostrum;

[0036] (2) Microfiltration sterilization

[0037] The skimmed bovine colostrum in step (1) is sterilized using a ceramic microfiltration device, wherein the ceramic membrane used for microfiltration has a pore size of 20 nm to 50 nm, and the permeate is collected;

[0038] (3) Concentration and desugaring

[0039] The permeate of step (2) is concentrated by low-temperature vacuum concentration technology to make the dry matter content of the bovine colostrum reach 20% to 30%; then the colostrum is fermented and desugared, and the concentrated colostrum is inoculated with Lactobacillus acidophilus (LA), Lactobacillus rhamnosus (LR), and Lactobacillus plantarum (LP) and calcium chloride is added as an auxiliary agent, and the fermentation temperature is 38-42° C. and the fermentation time is 5-10 hours;

[0040] (4) Drying

[0041] The fermented bovine colostrum is fed into an electrostatic spray drying tower, with the inlet air temperature controlled at 80°C to 110°C, the outlet air temperature controlled at 45°C to 60°C, the spray pressure maintained at a slightly negative pressure state of -10MPa to -20MPa, and a voltage applied to the atomizer port in the range of 10kV to 30kV;

[0042] (5) Cooling and packaging

[0043] The bovine colostrum powder dried in step (4) is cooled to a temperature below 30° C., and then sieved and nitrogen-filled and packaged to obtain the finished bovine colostrum powder.

[0044] Beneficial effects:

[0045] 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:

[0046] (1) Low-temperature vacuum concentration technology: Traditional concentration processes typically use high-temperature evaporation, which not only causes loss of nutrients in bovine colostrum but also increases the probability of oxidation reactions. The present invention uses low-temperature vacuum concentration technology to effectively reduce thermal damage and oxidation reactions of nutrients by concentrating at a lower temperature and in a vacuum environment, thereby maximizing the retention of active ingredients in bovine colostrum, such as immunoglobulins and lactoferrin. In addition, the design of using vacuum concentration before fermentation and desugaring can effectively reduce the production burden of the fermentation, sterilization, and drying processes.

[0047] (2) To avoid the discomfort caused by the high lactose content in bovine colostrum to lactose-intolerant people and to increase the protein content of colostrum powder, lactic acid bacteria fermentation is used for desugaring. The lactose content of the bovine colostrum concentrate obtained after concentration is as high as 15-18%. By adding a reasonable combination of lactic acid bacteria types and inoculation amount, the dual goals of desugaring and flavor optimization are achieved. After fermentation desugaring, the lactose content is reduced to less than 1%, and flavor testing has given the bovine colostrum powder a pleasant fermented yogurt flavor.

[0048] (3) Electrostatic spray drying process: Spray drying is a key step in the processing of bovine colostrum powder. However, the traditional spray drying process is prone to nutrient loss and oxidation reactions due to the high temperature and long drying process. The present invention uses a low vacuum and low temperature environment and introduces a high-voltage electric field during the spray drying process. The electric field imparts the outward distribution characteristics of the polar groups of the colostrum protein, effectively improving the stability and solubility of the active protein.

[0049] (4) Comprehensively optimized process flow: This invention not only innovates in a single process link, but also comprehensively optimizes the entire processing process. From strict control of raw material collection to refined operations in various links such as pretreatment, sterilization, concentration, drying and packaging, each step has been carefully designed and optimized to maximize the retention of nutrients, improve product quality and enhance storage stability. This full-process optimization design is groundbreaking in the field of bovine colostrum powder processing and provides a brand-new technical solution for the production of high-quality bovine colostrum powder.

[0050] (5) Significantly improved product quality, flavor, and stability: Through the application of the above-mentioned innovative process, the bovine colostrum powder produced by the present invention is significantly superior to traditional process products in terms of nutrient retention rate, taste, solubility, and storage stability. In addition, the lactose in the bovine colostrum is used for lactic acid fermentation, which can avoid the product causing discomfort to the lactose-intolerant group. It also gives the product the intestinal flora regulating effect of the lactic acid bacteria fermentation product and a pleasant yogurt fermentation flavor. Experimental data show that the bovine colostrum powder produced by the process of the present invention has a lactose content of less than 1%, a significant intestinal flora regulating effect, and a significantly increased abundance of characteristic yogurt fermentation volatile components such as diacetyl and acetaldehyde, and a significantly improved dispersibility. These significant performance improvements not only meet consumers' demand for high-quality bovine colostrum powder, but also provide an effective technical solution for the technical upgrading and product innovation of the bovine colostrum powder industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The microstructure and dispersion performance of bovine colostrum powder obtained from Example 1 and Comparative Example 4 are shown;

[0052] Figure 2 This is a diagram showing the regulatory effect of bovine colostrum powder obtained from Example 1 and Comparative Example 1 on intestinal flora;

[0053] Figure 3 This is a comparison chart of the effects of flavor compound content in bovine colostrum powder obtained by processing Example 1 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0054] 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.

[0055] The test method involved in the present invention is:

[0056] 1. Dispersion test

[0057] 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.

[0058] 2. Lactose content test

[0059] 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 was calculated based on the absorbance of the sample solution and the standard curve, combined with the dilution multiple of the sample solution and the sample weight.

[0060] 3. Organic acid content of intestinal flora

[0061] A representative intestinal flora suspension is cultured and the sample solution to be tested is added to the bacterial suspension. Fermentation is carried out under a strictly controlled anaerobic environment to simulate the physiological conditions in the intestine. After 24 hours of fermentation, changes in the content of short-chain organic acids such as acetic acid, propionic acid, and butyric acid are measured by high-performance liquid chromatography or gas chromatography.

[0062] 4. Diacetyl and acetaldehyde content test

[0063] (1) Establishment of diacetyl standard solution

[0064] Dilute the diacetyl standard solution to 0.03 μL / mL and use it as a mother solution to prepare diluents of different concentrations. Mix 5.0 mL of the diacetyl standard solution with an equal amount of trichloroacetic acid solution (8%). Add 0.5 mL of o-phenylenediamine solution (1%) to the first row of test tubes, and do not add o-phenylenediamine solution to the second row as a blank control; shake well, incubate in the dark for 30 minutes, and then add 4.0 mol / L hydrochloric acid to 12.5 mL to stop the reaction. The second row of test tubes is used as a blank control, and the absorbance value at a wavelength of 335 nm is measured using a UH5300 ultraviolet spectrophotometer. Construct a standard curve with the diacetyl concentration as the independent variable and the corresponding absorbance value as the dependent variable. Diacetyl concentration calibration curve: y = 0.0794x + 0.0293 (R 2 =0.9882).

[0065] (2) Determination of diacetyl concentration in fermentation broth

[0066] Take 30 mL of fermentation broth and add an equal volume of 8% (m / v) trichloroacetic acid solution. Vortex to mix thoroughly. Centrifuge at 6000g / min at 4°C for 15 minutes. After centrifugation, remove the supernatant and filter through filter paper to ensure the filtrate is clear and free of protein particles. Next, transfer 10 mL of the filtrate to separate centrifuge tubes and proceed as described above.

[0067] (3) Determination of acetaldehyde

[0068] Take 1 mL of the filtrate from step 2.2.6.2, add 7.5 mL of 0.1% NaHSO₃ solution, mix well, and let stand at room temperature for 30 minutes. After the reaction is complete, add 2-3 drops of 1% (m / v) starch solution (prepare as needed) and titrate with 0.01 mol / L standard iodine solution to the endpoint (light blue-purple, no fading within 30 seconds) (note that a brown burette is used). Record the amount of standard iodine solution used and perform parallel and control experiments simultaneously. Use deionized water as a control.

[0069]

[0070] V1- Volume of iodine standard solution consumed by blank group titration to endpoint (mL)

[0071] V2- Volume of iodine standard solution consumed by the sample group titrated to the endpoint (mL)

[0072] C-1 / 2I2 standard solution concentration (mol / L)

[0073] 0.022-Acetaldehyde chemical reaction basic unit g / moL

[0074] 1-Acetaldehyde sample mass mL.

[0075] Example 1

[0076] A method for preparing bovine colostrum powder by using lactic acid bacteria fermentation desugaring and electrostatic spray drying process comprises the following steps:

[0077] (1) Raw material collection and pretreatment

[0078] a. Select healthy and disease-free colostrum from cows within 3 days of calving as raw material to ensure its high quality and rich nutritional content;

[0079] b. Rapidly cool the collected bovine colostrum to below 4°C and refrigerate to inhibit the growth and reproduction of microorganisms and ensure the freshness of the raw materials;

[0080] c. The colostrum was filtered to remove impurities, blood clots, milk skin and other foreign matter, and then centrifuged at a centrifugal speed of 5000 rpm to remove the fat layer in the milk to obtain skimmed colostrum;

[0081] (2) Sterilization and concentration

[0082] The defatted bovine colostrum in step (1) is sterilized using a ceramic microfiltration device, wherein the size of the ceramic microfiltration membrane is 20 nm; the sterilized permeate is collected and concentrated under conditions of 40° C. and a vacuum degree of 0.08 MPa to obtain a bovine colostrum concentrate, wherein the dry matter content of the bovine colostrum reaches 20%;

[0083] (3) Fermentation and desugaring

[0084] The lactose content of the bovine colostrum concentrate obtained after concentration in step (2) was determined to be 16%. Lactic acid bacteria and calcium chloride were then added to the bovine colostrum concentrate and fermented at 40° C. for 8 h. The lactic acid bacteria in the fermentation system were Lactobacillus acidophilus (LA), Lactobacillus rhamnosus (LR), and Lactobacillus plantarum (LP), and the total inoculum size was 5×10 7 CFU, the ratio was 1:1:1; the concentration of calcium chloride was 20 mmol / L;

[0085] (4) Drying

[0086] The bovine colostrum fermented in step (3) is subjected to electrostatic spray drying, i.e., the bovine colostrum fermented in step (3) is fed into a spray drying tower, the air inlet temperature is controlled at 100° C., the air outlet temperature is controlled at 55° C., the spray pressure is maintained in a slightly negative pressure state of -10 MPa, and the voltage applied to the colostrum port is 20 kV, to obtain bovine colostrum powder;

[0087] (5) Cooling and packaging

[0088] The bovine colostrum powder dried in step (4) is cooled to a temperature below 30° C., and then sieved to remove coarse particles and lumps to obtain a finished bovine colostrum powder with uniform particle size and fineness; and then nitrogen-filled packaging is adopted, with the nitrogen filling amount being 15% of the packaging volume, and the packaging is sealed.

[0089] Example 2

[0090] The only difference from Example 1 is that during the fermentation process in step (3), the inoculum size in the fermentation system was adjusted to 5×10 8 CFU; other parameters and conditions were the same as in Example 1.

[0091] Example 3

[0092] The only difference from Example 1 is that during the fermentation process in step (3), the concentration of calcium chloride is adjusted to 40 mmol / L; other parameters and conditions are the same as those in Example 1.

[0093] Example 4

[0094] The only difference from Example 1 is that the bovine colostrum fermented in step (3) is subjected to electrostatic spray drying, that is, the fermented bovine colostrum is fed into a spray drying tower, the inlet air temperature is controlled at 110°C, the outlet air temperature is controlled at 60°C, the spray pressure is maintained at a slightly negative pressure state of -20 MPa, and the voltage applied to the sprayer port is 10 kV to obtain bovine colostrum powder; other parameters and conditions are the same as those in Example 1.

[0095] Comparative Example 1

[0096] The only difference from Example 1 is that the desugaring method in step (3) is adjusted to enzymatic desugaring; specifically, neutral lactase is used for hydrolysis, the addition amount of neutral lactase is 4000 U / g, the hydrolysis temperature is 55°C, and the hydrolysis time is 3 h; other parameters and conditions are the same as in Example 1.

[0097] Comparative Example 2

[0098] The only difference from Example 1 is that only Lactobacillus acidophilus (LA) and Lactobacillus plantarum (LP) are used in the fermentation process of step (3), the total inoculum amount remains unchanged, the addition ratio of the two lactic acid bacteria is 1:1, and other parameters and conditions are the same as those in Example 1.

[0099] Comparative Example 3

[0100] The only difference from Example 1 is that CaCl2 is not added as a fermentation aid during the fermentation process in step (3), and other parameters and conditions are the same as those in Example 1.

[0101] Comparative Example 4

[0102] The only difference from Example 1 is that the drying method of step (4) is adjusted to low-temperature vacuum freeze drying, the vacuum degree is set to -10 MPa, the inlet air temperature is 140°C, and the outlet air temperature is 90°C. Other parameters and conditions are the same as those in Example 1.

[0103] Result Analysis

[0104] 1. The lactose content and sensory evaluation of the bovine colostrum powder prepared in the examples and comparative examples were performed. The results are shown in Table 1:

[0105] Table 1. Lactose content and sensory scores of colostrum powder prepared in all examples and comparative examples

[0106]

[0107] As can be seen from the results in the table, the desugaring effect of each embodiment is good. The lactose content in the final bovine colostrum powder can be controlled to be less than 1%. The dispersion speed is fast, and uniform dispersion can be achieved by stirring in as fast as 10 seconds. The sensory score results are also higher than 90 points. This shows that after fermentation desugaring and electrostatic spray drying, the product can be given a good fermented yogurt flavor, while avoiding flavor deterioration caused by protein oxidation during the drying process.

[0108] In comparison, the sensory score of Comparative Example 1 was lower, indicating that although the traditional enzymatic desugaring with lactase can achieve a relatively good desugaring effect, there are inevitably some proteases impurities in lactase, which will cause protein hydrolysis, thereby increasing the content of free amino acids and small molecular peptides in the colostrum sample, promoting protein oxidation and Strecker degradation during the drying process to produce an unpleasant flavor, resulting in a low overall flavor score for the prepared colostrum powder sample.

[0109] Comparative Examples 2 and 3 differ from Example 1 in that the fermentation strain combination and the addition of the CaCl2 fermentation aid are adjusted. The results show that if only two lactic acid bacteria are used, the desugaring effect and overall flavor evaluation are lower than those of Example 1, indicating that the fermentation method of the three bacteria combination used in this aspect can promote the fermentation of each bacteria, improve fermentation efficiency, and produce more volatile components characteristic of yogurt, which is beneficial to the flavor enhancement of bovine colostrum powder products. The CaCl2 fermentation aid also has a very significant effect on improving fermentation efficiency. In Comparative Example 3, where no CaCl2 is added, the desugaring efficiency is significantly reduced, and the overall sensory score is also low, indicating that relatively few lactic acid bacteria characteristic flavor components are produced.

[0110] Comparative Example 4 differs from Example 1 by using conventional low-temperature spray drying instead of the electrostatic spray drying method proposed in the present invention. This method features higher air outlet and inlet temperatures and lacks an electric field at the spray drying port. As a result, the charged polar molecules fail to form an orderly, regular arrangement after atomization. This results in increased protein denaturation in the prepared colostrum powder, a bitter and unpleasant taste, and significantly reduced dispersibility. This demonstrates that the electrostatic spray drying method proposed in the present invention is significantly effective in optimizing product flavor and dispersibility.

[0111] 2. The microstructure of the colostrum powder prepared in Example 1 and Comparative Example 4 was analyzed. Figure 1 As shown:

[0112] Figure 1Comparing the microstructures and dispersion photographs of Example 1 and Comparative Example 4, it can be seen that the bovine colostrum powder prepared using electrostatic spray drying exhibits a regular spherical shape, while the bovine colostrum powder prepared using conventional low-temperature spray drying exhibits an uneven particle size distribution and significant aggregation, resulting in low solubility, unstable dispersion, and susceptibility to sedimentation in the dispersion. This result further demonstrates that the advantages of using electrostatic spray drying over conventional low-temperature spray drying lie in lower outlet and inlet temperatures, and the electric field at the spray drying port facilitates the formation of an orderly, regular arrangement of charged polar molecules after atomization, improving drying efficiency and preventing protein denaturation in the bovine colostrum powder, thereby enhancing dispersibility.

[0113] 3. The functional analysis of the colostrum powder prepared in Example 1 and Comparative Example 1 on regulating intestinal flora was as follows: Figure 2 As shown:

[0114] The main difference between Example 1 and Comparative Example 1 is that the desugaring method is different. Figure 2 The results show that oral administration of desugared bovine colostrum samples fermented with lactic acid bacteria has a significant regulatory effect on the intestinal flora. This suggests that the consumption of desugared bovine colostrum powder fermented with lactic acid bacteria increases the number of beneficial bacteria in the human body. Beneficial bacteria such as lactic acid bacteria and bifidobacteria proliferate under the influence of fermentation products. These beneficial bacteria produce organic acids during their metabolism. For example, lactic acid bacteria produce lactic acid through carbohydrate fermentation, while bifidobacteria produce short-chain fatty acids such as acetic acid, propionic acid, and butyric acid. This, in turn, increases the organic acid content in the intestine, reflecting a positive balance between beneficial and harmful bacteria in the intestinal flora, which helps maintain a stable intestinal microbiome. Harmful bacteria are also suppressed. The increased organic acid content lowers the pH of the intestinal environment. This acidic environment is not conducive to the growth and reproduction of certain harmful bacteria, such as Escherichia coli and Salmonella. This further adjusts the structure of the intestinal flora, reduces intestinal inflammation that can be caused by harmful bacteria, and maintains a balanced intestinal environment.

[0115] 4. The bovine colostrum powder prepared in the examples and comparative examples was subjected to flavor substance determination. The results are as follows: Figure 3 As shown:

[0116] from Figure 3 As can be seen, the concentration of the characteristic fermentation flavor of yogurt in Example 1 is high, while the sample desugared using lactase contains almost no diacetyl and acetaldehyde, two characteristic fermentation flavors. In Comparative Example 1, desugaring using traditional lactase resulted in a significant decrease in the abundance of characteristic volatile components. The sample without the fermentation accelerator CaCl2 showed a significant decrease in fermentation level, with lower diacetyl and acetaldehyde contents. This result demonstrates that the inoculum size of the strain designed in the present invention and the introduction of the CaCl2 fermentation aid are both important factors in determining the efficiency of fermentation desugaring and the flavor of the final bovine colostrum powder.

[0117] 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 preparing bovine colostrum powder by using lactic acid bacteria fermentation desugaring and electrostatic spray drying process, characterized in that: The method comprises the following steps: (1) Raw material pretreatment The collected colostrum is quickly cooled to 0-4°C and refrigerated; it is then filtered and centrifuged to remove the fat layer in the milk to obtain skimmed colostrum; (2) Microfiltration sterilization The skimmed bovine colostrum in step (1) is sterilized using a ceramic microfiltration device, wherein the ceramic membrane used for microfiltration has a pore size of 20 nm to 50 nm, and the permeate is collected; (3) Concentration and desugaring The permeate of step (2) is concentrated by low-temperature vacuum concentration technology to make the dry matter content of the bovine colostrum reach 20% to 30%; then the colostrum is fermented and desugared, and Lactobacillus acidophilus, Lactobacillus rhamnosus, and Lactobacillus plantarum are inoculated into the concentrated bovine colostrum, and calcium chloride is added as an auxiliary agent. The fermentation temperature is 38-42° C. and the fermentation time is 5-10 hours; (4) Drying The fermented bovine colostrum is fed into an electrostatic spray drying tower, with the inlet air temperature controlled at 80°C to 110°C, the outlet air temperature controlled at 45°C to 60°C, the spray pressure maintained at a slightly negative pressure state of -10MPa to -20MPa, and a voltage applied to the atomizer port in the range of 10kV to 30kV; (5) Cooling and packaging The bovine colostrum powder dried in step (4) is cooled to a temperature below 30° C., and then sieved and nitrogen-filled and packaged to obtain the finished bovine colostrum powder.

2. The processing method according to claim 1, characterized in that: The colostrum in step (1) is from healthy and disease-free bovine colostrum produced within 3 days after calving, ensuring its high quality and rich nutritional ingredients.

3. The processing method according to claim 1, characterized in that: The centrifugal speed in step (1) is 5000-8000 rpm.

4. The processing method according to claim 1, characterized in that: The low-temperature vacuum concentration technology in step (3) is used for concentration at a temperature of 40°C to 50°C and a vacuum degree of 0.08MPa to 0.09MPa.

5. The processing method according to claim 1, characterized in that: The total inoculum amount of Lactobacillus acidophilus, Lactobacillus rhamnosus and Lactobacillus plantarum in step (3) is 1×10 7 -5×10 8 CFU.

6. The processing method according to claim 1, characterized in that: In the fermentation and desugaring system of step (3), the concentration of calcium chloride is 20-40 mmol / L.

7. The method according to claim 1, characterized in that The nitrogen filling amount of the nitrogen-filled package in step (5) is 10% to 15% of the package volume.

8. Bovine colostrum powder obtained by the processing method according to any one of claims 1 to 7.

9. Use of the bovine colostrum powder according to claim 8 in preparing functional foods.

10. A method for improving the nutritional quality, stability and dispersibility of bovine colostrum powder, characterized in that: The method comprises the following steps: (1) Raw material pretreatment The collected colostrum is quickly cooled to 0-4°C and refrigerated; it is then filtered and centrifuged to remove the fat layer in the milk to obtain skimmed colostrum; (2) Microfiltration sterilization The skimmed bovine colostrum in step (1) is sterilized using a ceramic microfiltration device, wherein the ceramic membrane used for microfiltration has a pore size of 20 nm to 50 nm, and the permeate is collected; (3) Concentration and desugaring The permeate of step (2) is concentrated by low-temperature vacuum concentration technology to make the dry matter content of the bovine colostrum reach 20% to 30%; then the colostrum is fermented and desugared, and Lactobacillus acidophilus, Lactobacillus rhamnosus, and Lactobacillus plantarum are inoculated into the concentrated bovine colostrum, and calcium chloride is added as an auxiliary agent. The fermentation temperature is 38-42° C. and the fermentation time is 5-10 hours; (4) Drying The fermented bovine colostrum is fed into an electrostatic spray drying tower, with the inlet air temperature controlled at 80°C to 110°C, the outlet air temperature controlled at 45°C to 60°C, the spray pressure maintained at a slightly negative pressure state of -10MPa to -20MPa, and a voltage applied to the atomizer port in the range of 10kV to 30kV; (5) Cooling and packaging The bovine colostrum powder dried in step (4) is cooled to a temperature below 30° C., and then sieved and nitrogen-filled and packaged to obtain the finished bovine colostrum powder.

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