Low-water-activity stable bone mineral nutrient support composite probiotic powder and preparation method thereof

Abstract

This invention discloses a low-water-activity stable bone mineral nutritional support compound probiotic powder and its preparation method. The compound probiotic powder is composed of five strains of bacteria, namely Bacillus subtilis, Lactobacillus paracasei, Lactobacillus plantarum, Propionibacterium fischeri, and Lactobacillus casei, in proportions of 10%~30%, 15%~30%, 15%~30%, 5%~20%, and 10%~25%, respectively. It is supplemented with 10~80 μg of vitamin K2-MK-7, 5~25 μg of vitamin D3, calcium, magnesium, and zinc mineral components, and a prebiotic carrier. The finished product of this invention has a repose angle of 37.2°, a viable bacteria retention rate of 72.1% after 12 months, and soluble calcium, magnesium, and zinc retention rates of 68.5%, 72.4%, and 70.1%, respectively. This invention achieves the industrial-scale preparation of a bone mineral nutritional support compound probiotic powder with good flowability and long-term stability, suitable for use as a dietary supplement for bone nutritional support in healthy adults and middle-aged and elderly individuals.

Description

Technical Field

[0001] This invention belongs to the technical field of probiotic powder preparations, bone mineral nutrition support and dietary supplements, and particularly relates to a low water activity stable bone mineral nutrition support compound probiotic powder and its preparation method. Background Technology

[0002] Bone health-related dietary supplements are typically designed around nutrients such as calcium, magnesium, zinc, vitamin D3, and vitamin K2. Calcium is a core mineral component of bones, vitamin D3 promotes intestinal calcium absorption, and vitamin K2 participates in the carboxylation activation process of osteocalcin; the synergistic effect of these three is crucial for bone health. Meanwhile, probiotics and prebiotics are valuable for research on the intestinal environment, mineral solubility, short-chain fatty acid formation, and nutrient absorption environment. Therefore, combining probiotics with mineral nutrition modules is a viable direction for bone mineral nutrition support products.

[0003] Existing technologies have attempted to combine probiotics with minerals and vitamins. For example, CN115089618B discloses a pharmaceutical composition for preventing and treating osteoporosis, consisting of calcium carbonate, vitamin D3, vitamin K2, Bacillus coagulans, and amino acids. Other technologies involve the application of compound probiotic agents in products that promote the absorption of vitamins and / or minerals. Furthermore, there are technologies that combine lactic acid bacteria with bone meal to prepare fermentation broth for calcium supplementation and bone formation.

[0004] However, existing nutritional supplements often simply combine calcium, magnesium, zinc, vitamin D3 / K2, probiotics, fruit powder, and prebiotics. This type of solution has the following shortcomings: First, there is a lack of systematic design regarding strain ratios and nutrient dosage windows, and the interactions between components are not adequately considered. Mineral salts have strong hygroscopic properties, and direct contact with probiotics can easily lead to increased local water activity, affecting the long-term survival rate of probiotics.

[0005] Second, existing processes mostly use a one-time direct mixing method without strict control over the humidity of the mixing environment and the water activity of the materials, which can easily lead to problems such as powder absorbing moisture and clumping, resulting in a significant decrease in the number of live bacteria after storage.

[0006] Third, although Bacillus subtilis can be used as a Bacillus module with good tolerance and powder stability, the existing technology often attributes the production of vitamin K2 to the strain's own metabolism. This efficacy attribution method carries the risk of uncontrollable raw material sources and product quality.

[0007] Fourth, existing solutions lack clear control indicators and verification data for finished product water activity and long-term viable bacteria retention rate.

[0008] Therefore, there is an urgent need to develop a bone mineral nutrition support compound probiotic powder with a clear structure, reproducible process, and verifiable stability data. Summary of the Invention

[0009] In order to overcome the above-mentioned defects of the prior art, the present invention provides a low water activity stable bone mineral nutritional support compound probiotic powder and its preparation method, which solves the problems of existing bone mineral probiotic products being mostly simple blends, lacking systematic design of strain ratio, dosage window and low water activity post-mixing process, resulting in powder hygroscopic agglomeration and a sharp drop in the shelf life of live bacteria.

[0010] To achieve the above objectives, the present invention provides the following technical solution: A low water activity stable bone mineral nutrition support compound probiotic powder and its preparation method are disclosed. Each unit dose comprises five strains of compound probiotics, exogenous vitamin K2, vitamin D3, mineral components, a prebiotic carrier, and optional excipients. The five strains of compound probiotics are Bacillus subtilis, Lactaseibacillus paracasei, Lactiplantibacillus plantarum, Propionibacterium freudenreichii, and Lactaseibacillus casei. The finished compound probiotic powder has a water activity (Aw) not exceeding 0.25, a moisture content not exceeding 5.0%, and a total viable bacteria retention rate of not less than 65% after 12 months of sealed storage at 25°C and 60% relative humidity.

[0011] Preferably, the Bacillus subtilis is DSM1088 or a food-grade production strain with a traceable source relationship; the Lactobacillus paracasei is DSM5622 or ATCC25302 or a food-grade production strain with a traceable source relationship; the Lactobacillus plantarum is DSM20174 or ATCC14917 or a food-grade production strain with a traceable source relationship; the Propionibacterium freundii is DSM20271 or ATCC6207 or a food-grade production strain with a traceable source relationship; and the Lactobacillus casei is DSM20011 or ATCC393 or a food-grade production strain with a traceable source relationship.

[0012] Preferably, based on the total number of live bacteria added during preparation, Bacillus subtilis accounts for 10%–30%, Lactobacillus paracasei accounts for 15%–30%, Lactobacillus plantarum accounts for 15%–30%, Propionibacterium fischeri accounts for 5%–20%, and Lactobacillus casei accounts for 10%–25%.

[0013] Preferably, the total number of viable bacteria added during preparation of each unit dose is 1.0 × 10⁻⁶. 10 CFU to 5.0×10 10 CFU.

[0014] Preferably, the exogenous vitamin K2 is vitamin K2-MK-7, with a dosage of 10-80 μg per unit; the vitamin D3 is 5-25 μg per unit; the mineral components include calcium salts, magnesium salts, and zinc salts, wherein the calcium salt is provided as one or more of calcium glycinate, calcium citrate, calcium carbonate, or calcium malate, the magnesium salt is provided as one or more of magnesium glycinate, magnesium citrate, or magnesium oxide, and the zinc salt is provided as one or more of zinc glycinate, zinc gluconate, or zinc citrate.

[0015] Preferably, the prebiotic carrier includes one or more of fructooligosaccharides, inulin, resistant dextrin, galactooligosaccharides, gum arabic, and maltodextrin; the optional excipients include one or more of vitamin C, blueberry powder, apple powder, lemon powder, silicon dioxide, tricalcium phosphate, microcrystalline cellulose, and natural aroma components.

[0016] Preferably, the exogenous vitamin K2, vitamin D3, and mineral components are first prepared into a nutrient premix powder with a portion of the prebiotic carrier, and the water activity (Aw) of the nutrient premix powder is controlled to be no higher than 0.20; the five strains of compound probiotics are first prepared into a probiotic premix powder with another portion of the prebiotic carrier; the nutrient premix powder and the probiotic premix powder are then mixed at 15-25°C and relative humidity no higher than 30%, the mixing speed is 5-25 rpm, the single mixing time is 8-20 minutes, and the material temperature during the mixing process does not exceed 25°C.

[0017] Preferably, the compound probiotic powder is packaged in aluminum foil strips, composite aluminum film bags, high-barrier bottles with desiccant, or equivalent moisture-proof packaging. When stored at 25°C and 60% relative humidity for 12 months after packaging, the water activity Aw is not higher than 0.30.

[0018] Preferably, a method for preparing a low water activity stabilized bone mineral nutritional support compound probiotic powder includes: S1: Premix vitamin K2, vitamin D3, calcium salt, magnesium salt, zinc salt and some prebiotic carrier, and control the water activity Aw to be no higher than 0.20 to obtain mineral-vitamin nutrient premix powder; S2: Mix the five strains of compound probiotic powder consisting of Bacillus subtilis, Lactobacillus paracasei, Lactobacillus plantarum, Propionibacterium fischeri and Lactobacillus casei with another part of the prebiotic carrier at 15-25℃ and relative humidity not higher than 30% to obtain probiotic premix powder. S3: Under conditions of 15-25℃ and relative humidity not exceeding 30%, the nutrient premix powder and the probiotic premix powder are mixed at a speed of 5-25 rpm for 8-20 minutes, with the material temperature not exceeding 25℃, and then subjected to low-shear mixing to ensure that the water activity Aw of the finished product is not higher than 0.25 and the moisture content is not higher than 5.0%. S4: The total powder mixture is sieved through a 20-80 mesh screen and then packaged with moisture-proof packaging.

[0019] Preferably, the total viable bacteria retention rate of the finished product is not less than 65% under sealed storage conditions of 25°C and 60% relative humidity for 12 months.

[0020] The technical effects and advantages of the low water activity stabilized bone mineral nutritional support compound probiotic powder and its preparation method of this invention are as follows: 1. In this invention, *Bacillus subtilis* provides a spore stability module, *Lactobacillus paracasei* and *Lactobacillus plantarum* provide a lactobacillus intestinal nutrition support module, *Propionibacterium fischeri* provides a fermentation metabolite concept module, and *Lactobacillus casei* provides a basic lactobacillus nutrition support module. The five strains are rationally matched in terms of live bacteria ratio, and the functional positioning of each strain is clear.

[0021] 2. This invention positions Bacillus subtilis as a Bacillus stability module and clearly positions vitamin K2 as an exogenous K2 nutrition module, avoiding the risk of attributing the source of vitamin K2 in the finished product to the strain's own generation and reducing the problem of unclear attribution of raw material source and efficacy.

[0022] 3. This invention employs a step-by-step preparation process of mineral-vitamin premixed powder and probiotic premixed powder, followed by low-temperature and low-humidity mixing. This avoids the localized hypertonic environment and oxidative damage caused by direct contact between mineral salts, vitamin K2 / D3, and probiotics. Example data shows that the 12-month viable bacteria retention rate of the step-by-step premixed sample reached 72.1%, while the comparative sample with a single direct mixing method only achieved 48.4%.

[0023] 4. This invention effectively inhibits microbial metabolic activity and chemical degradation reactions by strictly controlling the finished product's water activity (Aw) to no higher than 0.25 and moisture content to no higher than 5.0%. Combined with moisture-resistant packaging, the water activity remains no higher than 0.30 even 12 months after packaging, ensuring the long-term survival of probiotics.

[0024] 5. This invention, when subjected to low-shear post-mixing at 15-25℃ and relative humidity not exceeding 30%, produces a finished product with an angle of repose of 37.2° and a powder content of 20-80 mesh reaching 87.6%, which is significantly better than the comparative example and has good compatibility with powder packaging processes.

[0025] 6. Under simulated digestion conditions, the soluble calcium retention rate of the sample of this invention was 68.5%, the soluble magnesium retention rate was 72.4%, and the soluble zinc retention rate was 70.1%, all of which were significantly better than the comparative example, indicating that the formulation and process design of this invention are beneficial to the retention of mineral solubility under digestion conditions. Attached Figure Description

[0026] Figure 1 This is a flowchart of a low water activity stable bone mineral nutritional support compound probiotic powder and its preparation method proposed in this invention. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "includes..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0029] refer to Figure 1 This invention provides a low water activity stabilized bone mineral nutrition support compound probiotic powder and its preparation method. The compound probiotic powder, per unit dose, comprises five strains of compound probiotics: Bacillus subtilis, Lactobacillus paracasei, Lactobacillus plantarum, Propionibacterium fischeri, and Lactobacillus casei, as well as exogenous vitamin K2, vitamin D3, mineral components, prebiotic carriers, and optional excipients. The five strains, based on the total live bacteria count added during preparation, account for 10%–30%, 15%–30%, 15%–30%, 5%–20%, and 10%–25% respectively, with a total live bacteria count of 1.0 × 10⁻⁶ per unit dose. 10 ~5.0×10 10The compound probiotic powder contains 10-80 μg of CFU (Cellular Fuel), 5-25 μg of Vitamin K2-MK-7, and 5-25 μg of Vitamin D3. The mineral components include calcium, magnesium, and zinc salts. The compound probiotic powder is prepared by mixing exogenous Vitamin K2, Vitamin D3, and mineral components with a portion of a prebiotic carrier to form a nutrient premix. Five strains of compound probiotics are then mixed with another portion of the prebiotic carrier to form a probiotic premix. The two mixtures are then combined at 5-25 rpm for 8-20 minutes at 15-25°C and a relative humidity not exceeding 30% to ensure the material temperature does not exceed 25°C. The finished product is packaged in aluminum foil strips, composite aluminum film bags, high-barrier bottles with desiccants, or equivalent moisture-proof packaging. The final product has a water activity (Aw) not exceeding 0.25 and a moisture content not exceeding 5.0%. After packaging, when stored at 25°C and 60% relative humidity for 12 months, the water activity (Aw) is not higher than 0.30, and the total viable bacteria retention rate is not less than 65%. This invention solves the technical problems of existing bone mineral probiotic products, such as simple blending, lack of strain ratio and dosage window system design, powder hygroscopic clumping, and sharp drop in viable bacteria count after storage, by combining step-by-step premixing, low-temperature and low-humidity post-mixing, and moisture-resistant packaging. It realizes the industrial preparation of a bone mineral nutritional support compound probiotic powder with good powder flowability, long-term viable bacteria stability, and mineral solubility. It is suitable for dietary supplementation of bone mineral nutrition support for healthy adults, people with insufficient bone mineral intake, or middle-aged and elderly people.

[0030] Terminology Explanation: "Exogenous Vitamin K2 Nutritional Module" refers to a nutritional module formed by adding food-grade vitamin K2 raw materials, and does not mean that the vitamin K2 in the compound probiotic powder is generated by Bacillus subtilis or other strains in the finished product.

[0031] The "Bacillus stability module" refers to Bacillus subtilis participating in the construction of compound bacterial powder as a spore component with good tolerance. It is not equivalent to limiting the specific fermentation source or vitamin K2 production capacity of the strain.

[0032] "Traceable food-grade production strains" refer to strains that can be traced back to the corresponding public collection strain or its equivalent food-grade production source through strain source documents, strain identification reports, whole genome sequencing data, and food-grade production records.

[0033] "Bone mineral nutritional support" refers to dietary supplementation and nutritional management for healthy individuals, and does not involve the diagnosis, treatment, or prevention of bone-related diseases or other diseases.

[0034] Detection method: Water activity Aw: Measured using a calibrated water activity meter at 25℃. Each sample was measured in triplicate, and the average value was taken.

[0035] Moisture content: determined by loss on drying or Karl Fischer method, and the result is expressed as a percentage by mass.

[0036] Viable cell count: Plate counting was performed using selective or semi-selective culture media suitable for the growth of each strain; for multi-strain samples, PMA-qPCR or digital PCR could be used to help confirm the relative abundance of strains.

[0037] Viable cell retention rate: calculated by dividing the total number of viable cells after storage by the initial total number of viable cells. The storage conditions are 25°C, 60% relative humidity, sealed packaging, and a storage time of 12 months.

[0038] Powder flowability: The angle of repose was determined by the fixed funnel method, and the proportion of 20-80 mesh powder was determined by the standard sieve method.

[0039] Mineral solubility after simulated digestion: The sample was continuously treated with simulated gastric juice and simulated intestinal juice at unit doses. After centrifugation, the calcium, magnesium and zinc contents in the supernatant were measured, and the solubility retention rate was calculated based on the amount added.

[0040] Example 1: Strain composition and ratio.

[0041] This example illustrates the composition of five strains of compound probiotics and the proportion of live bacteria added during preparation.

[0042]

[0043] All of the above strains can be traced back to the corresponding public collection strains or their equivalent food-grade production sources through strain source documents, strain identification reports, whole genome sequencing data, and food-grade production records.

[0044] Example 2: Unit dose formulation.

[0045] This example illustrates the formulation composition for each unit dose (3.0g per sachet).

[0046]

[0047] Example 3: Preparation process.

[0048] This embodiment illustrates the complete preparation process of compound probiotic powder.

[0049] S1. Prepare mineral-vitamin premix powder.

[0050] Vitamin K2-MK-7 45μg, Vitamin D3 10μg, calcium glycine / calcium citrate compound 700mg, magnesium glycine 120mg, zinc glycine 12mg, Vitamin C 40mg, silicon dioxide 10mg, and a portion of prebiotic carriers (approximately 800mg of fructooligosaccharides / inulin / resistant dextrin) were premixed in an environment with a relative humidity not exceeding 30% to obtain a mineral-vitamin nutritional premix powder, with its water activity Aw controlled to be not higher than 0.20.

[0051] S2. Prepare probiotic premix powder.

[0052] Five strains of compound probiotic powder (containing Bacillus subtilis, Lactobacillus paracasei, Lactobacillus plantarum, Propionibacterium fischeri, and Lactobacillus casei, with a total viable count of 2.0 × 10⁻⁶) were used. 10 CFU and another part of the prebiotic carrier (approximately 550 mg of fructooligosaccharides / inulin / resistant dextrin) are mixed at low speed at 15-25°C and relative humidity not exceeding 30% to obtain probiotic premix powder.

[0053] S3. Mix at low temperature and low humidity.

[0054] The nutrient premix powder and probiotic premix powder are mixed under low shear conditions at 15-25℃ and relative humidity not exceeding 30%, with a mixing speed of 5-25 rpm and a mixing time of 8-20 minutes. The material temperature during the mixing process does not exceed 25℃.

[0055] S4. Screening and moisture-proof packaging.

[0056] The total powder mixture is sieved through a 20-80 mesh screen and immediately packaged in aluminum foil strips or equivalent moisture-proof packaging, with each bag containing 3.0g.

[0057] Example 4: Comparative Design.

[0058] To verify the superiority of the process of the present invention, the following comparative examples are set up:

[0059] Example 5: Powder stability.

[0060] Following the above testing methods, the water activity, moisture content, angle of repose, and percentage of 20–80 mesh powder were determined for each sample. The results are as follows:

[0061] The results showed that the water activity (0.20) and moisture content (4.1%) of the sample in the embodiment of the present invention were lower than those of the comparative examples. A smaller angle of repose indicates better flowability; the angle of repose of the sample in the embodiment was 37.2°, significantly smaller than that of comparative example A (45.0°) and comparative example B (46.5°), indicating that the stepwise premixing and low-temperature, low-humidity post-mixing process of the present invention effectively improved the powder flowability. The proportion of 20-80 mesh powder in the sample in the embodiment reached 87.6%, which was also superior to that of the comparative examples.

[0062] Example 6: 12-month viable bacteria retention rate and vitamin K2 retention rate.

[0063] Each sample was sealed and stored at 25℃ and 60% relative humidity for 12 months. The total viable count and vitamin K2 content were measured at the initial stage and after 12 months. The viable count retention rate and vitamin K2 retention rate were calculated. The results are as follows:

[0064] The results showed that the viable bacterial retention rate of the samples in the embodiments of the present invention reached 72.1% after 12 months, significantly higher than that of comparative examples A (48.4%), B (42.7%), C (52.5%), and D (49.8%). The vitamin K2 retention rate reached 86.4%, also superior to the comparative examples. This indicates that the stepwise premixing, low-temperature and low-humidity post-mixing, and moisture-barrier packaging process of the present invention can significantly reduce the adverse effects of localized moisture absorption and direct contact of nutrient components on viable bacterial retention rate and vitamin K2 stability.

[0065] Example 7: Simulating the solubility of minerals after digestion.

[0066] The samples from the examples, Comparative Example A, and Comparative Example D were continuously treated with simulated gastric and intestinal fluids at unit doses. After centrifugation, the calcium, magnesium, and zinc contents in the supernatant were measured. The solubility retention rate was calculated based on the amount added. The results are as follows:

[0067] The results showed that the retention rates of soluble calcium, magnesium, and zinc in the samples of the present invention were significantly higher than those in the comparative example. This indicates that the formulation design and stepwise premixing process of the present invention are beneficial to the retention of mineral solubility under simulated digestion conditions.

[0068] The above simulated digestion evaluation is used to characterize the solubility retention trend of mineral components in powder formulations under in vitro digestion conditions, and is not intended as direct evidence of disease treatment effects or improvement in human bone density.

[0069] Industrial application This invention can be used to prepare products such as bone mineral nutritional support strip powder, adult calcium, magnesium, zinc, vitamin D3 / K2 nutritional powder, and daily nutritional support powder for middle-aged and elderly people. In actual commercialization, the raw material access, labeling, target consumer groups, strain origin certification, food-grade production records, Certificate of Authorization (COA), and commercial use documents should be verified in accordance with the regulations of the target market.

[0070] Industrial applicability The present invention provides a low water activity stable bone mineral nutritional support compound probiotic powder and its preparation method. The process conditions are well-defined, the operation is controllable, and it is suitable for large-scale industrial production. The product has good powder flowability, long-term storage stability, and mineral solubility, and can be widely used in the field of dietary supplements, demonstrating significant industrial practical value.

[0071] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0072] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low water activity stabilized bone mineral nutritional support compound probiotic powder, characterized in that, Each unit dose consists of five strains of compound probiotics, exogenous vitamin K2, vitamin D3, mineral components, prebiotic carriers, and optional excipients. The five strains of compound probiotics are Bacillus subtilis, Lactaseibacillus paracasei, Lactiplantibacillus plantarum, Propionibacterium freudenreichii, and Lactaseibacillus casei. The finished compound probiotic powder has a water activity (Aw) of no more than 0.25, a moisture content of no more than 5.0%, and a total viable bacteria retention rate of no less than 65% after 12 months of sealed storage at 25°C and 60% relative humidity.

2. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 1, characterized in that, The *Bacillus subtilis* strain is DSM1088 or a food-grade production strain with a traceable origin; the *Lactobacillus paracasei* strain is DSM5622 or ATCC25302 or a food-grade production strain with a traceable origin; the *Lactobacillus plantarum* strain is DSM20174 or ATCC14917 or a food-grade production strain with a traceable origin; the *Propionibacterium freundii* strain is DSM20271 or ATCC6207 or a food-grade production strain with a traceable origin; and the *Lactobacillus casei* strain is DSM20011 or ATCC393 or a food-grade production strain with a traceable origin.

3. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 2, characterized in that, Based on the total number of live bacteria added during preparation, Bacillus subtilis accounts for 10%–30%, Lactobacillus paracasei accounts for 15%–30%, Lactobacillus plantarum accounts for 15%–30%, Propionibacterium fischeri accounts for 5%–20%, and Lactobacillus casei accounts for 10%–25%.

4. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 3, characterized in that, Each unit dose contains 1.0 × 10⁻⁶ total live bacteria added during preparation. 10 CFU to 5.0×10 10 CFU.

5. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 4, characterized in that, The exogenous vitamin K2 is vitamin K2-MK-7, with a dose of 10-80 μg per unit; the vitamin D3 is 5-25 μg per unit; the mineral components include calcium salts, magnesium salts, and zinc salts, wherein the calcium salt is provided as one or more of calcium glycinate, calcium citrate, calcium carbonate, or calcium malate, the magnesium salt is provided as one or more of magnesium glycinate, magnesium citrate, or magnesium oxide, and the zinc salt is provided as one or more of zinc glycinate, zinc gluconate, or zinc citrate.

6. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 5, characterized in that, The prebiotic carrier includes one or more of the following: fructooligosaccharides, inulin, resistant dextrin, galactooligosaccharides, gum arabic, and maltodextrin; the optional excipients include one or more of the following: vitamin C, blueberry powder, apple powder, lemon powder, silicon dioxide, tricalcium phosphate, microcrystalline cellulose, and natural aroma components.

7. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 6, characterized in that, The exogenous vitamin K2, vitamin D3, and mineral components are first prepared into a nutrient premix powder with a portion of the prebiotic carrier, and the water activity (Aw) of the nutrient premix powder is controlled to be no higher than 0.

20. The five strains of compound probiotics are first prepared into a probiotic premix powder with another portion of the prebiotic carrier. The nutrient premix powder and the probiotic premix powder are then mixed at 15-25°C and relative humidity no higher than 30%, with a mixing speed of 5-25 rpm and a single mixing time of 8-20 minutes. The material temperature during the mixing process does not exceed 25°C.

8. The low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 7, characterized in that, The compound probiotic powder is packaged in aluminum foil strips, composite aluminum film bags, high-barrier bottles with desiccant, or equivalent moisture-proof packaging. When stored at 25°C and 60% relative humidity for 12 months after packaging, the water activity Aw is no higher than 0.

30.

9. A method for preparing a low water activity stabilized bone mineral nutritional support compound probiotic powder as described in any one of claims 1-8, characterized in that, include: S1: Premix vitamin K2, vitamin D3, calcium salt, magnesium salt, zinc salt and some prebiotic carrier, and control the water activity Aw to be no higher than 0.20 to obtain mineral-vitamin nutrient premix powder; S2: Mix the five strains of compound probiotic powder consisting of Bacillus subtilis, Lactobacillus paracasei, Lactobacillus plantarum, Propionibacterium fischeri and Lactobacillus casei with another part of the prebiotic carrier at 15-25℃ and relative humidity not higher than 30% to obtain probiotic premix powder. S3: Under conditions of 15-25℃ and relative humidity not exceeding 30%, the nutrient premix powder and the probiotic premix powder are mixed at a speed of 5-25 rpm for 8-20 minutes, with the material temperature not exceeding 25℃, and then subjected to low-shear mixing to ensure that the water activity Aw of the finished product is not higher than 0.25 and the moisture content is not higher than 5.0%. S4: The total powder mixture is sieved through a 20-80 mesh screen and then packaged with moisture-proof packaging.

10. The preparation method of a low water activity stabilized bone mineral nutritional support compound probiotic powder as described in claim 9, characterized in that, The total viable bacteria retention rate of the finished product should not be less than 65% for 12 months under sealed storage conditions of 25℃ and 60% relative humidity.

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