A gastro-intestinal soluble probiotic granule and its preparation method and application

Abstract

The present application relates to the technical field of probiotic preparation, and particularly relates to a gastroenteric probiotic granule and a preparation method and application thereof, the coated granule comprises: a probiotic core material, and a coating layer coated outside the core material; the coating layer is formed by a composite coating material of hydrogenated palm oil and stearic acid surface modified nano active calcium carbonate, wherein the stearic acid surface modified nano active calcium carbonate accounts for 50% to 60% of the total mass of the composite coating material, and the weight ratio of the coating layer to the core material is 20% to 25%. The present application utilizes hydrogenated palm oil to form a hydrophobic physical barrier, and simultaneously utilizes nano calcium carbonate to slowly neutralize acidity in gastric acid, generate bubbles to form a microenvironment buffer, and realize a dual synergistic protection mechanism of physical barrier and chemical buffer. In vitro tests show that the probiotic granule prepared by the present application has a survival rate of greater than or equal to 90% after being treated in artificial gastric juice for 2 hours, and a release rate of greater than or equal to 93% after being treated in artificial intestinal juice for 2 hours, which is significantly better than traditional coating technology, and has a broad industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of probiotic preparation technology, and in particular to a gastrointestinal-coated probiotic granule, its preparation method, and its application. Background Technology

[0002] The efficacy of probiotics in improving gut health, regulating immunity, and treating inflammatory bowel disease has been widely confirmed. However, oral probiotics face a severe gastrointestinal barrier during delivery: the highly acidic environment of gastric juice (pH 1.2–2.5) and high concentrations of bile salts can lead to the inactivation of a large number of probiotics, with a survival rate of less than 1% for live bacteria. Therefore, developing coating technologies that can protect probiotics from damage by gastric acid and bile and achieve targeted release into the gut is a research hotspot and a key to industrialization in this field.

[0003] Currently, gastrointestinal protection strategies for probiotics are mainly divided into two categories: bio-interface mineralization coatings and traditional physical coating technologies.

[0004] Bio-interface mineralization coatings are a novel protective strategy that has emerged in recent years. For example, Liu Jinyao, Cao Zhenping, Wu Feng, and others reported a bio-interface mineralization method in *Science Advances* (2023) that generates an ultrathin calcium carbonate mineral coating in situ on the surface of probiotics (such as *Bacteroides fragilis* BF839) using sodium carbonate and calcium chloride. This coating can undergo a neutralization reaction in gastric acid, consuming the gastric acid and releasing the bacterial cells. Simultaneously, the released calcium ions can trigger bile acid micelle aggregation, reducing the damage of bile to the bacteria. However, this type of mineralization technology still has significant limitations in practical production applications: First, the coating formation depends on the electrostatic interaction between the cell surface and ions. The cell wall composition and surface charge of different strains vary greatly, making it difficult to precisely control the coating uniformity and thickness, resulting in poor batch-to-batch reproducibility. Second, the mineralization process requires strict control of reaction conditions, resulting in a narrow operating window. Furthermore, the full anaerobic treatment by obligate anaerobic bacteria further increases the complexity of the process. Third, the ultrathin mineralized layer formed is easily damaged by mechanical friction or environmental humidity during long-term storage, and its storage stability needs to be verified. Fourth, this technology is currently still in the laboratory pilot stage, and large-scale scaling faces many engineering challenges.

[0005] Traditional physical coating technology primarily employs fluidized bed processes to coat enteric-coating materials onto the surface of probiotic particles, forming a physical barrier. Hydrogenated vegetable oils (such as hydrogenated palm oil) have been used as coating materials due to their excellent hydrophobicity and enteric properties. However, while existing technologies using only hydrogenated oils as a coating layer can provide some gastric acid barrier protection, their protective mechanism is relatively simple, relying mainly on a physical barrier. When gastric acid secretion is excessive or gastric emptying time is prolonged, a single oil layer may lose its protective effect due to prolonged acid exposure.

[0006] To enhance gastric acid buffering capacity, researchers have attempted to add alkaline excipients such as calcium carbonate to coating formulations. However, in existing technologies, commonly used polymeric coating materials (such as acrylic resins) have poor compatibility with nano-sized active calcium carbonate. Calcium carbonate particles easily aggregate and precipitate in the coating solution, leading to problems such as poor coating solution stability, spray gun clogging, and decreased coating uniformity, thus limiting the application of high-concentration calcium carbonate in coating formulations. To address these issues, current technologies have not yet provided a probiotic coating method that can achieve stable dispersion of high-concentration calcium carbonate, exert a synergistic protective effect of physical barriers and chemical buffering, and is suitable for industrial-scale production. Summary of the Invention

[0007] The purpose of this invention is to provide a gastrointestinal-coated probiotic granule, its preparation method, and its application, in order to solve the technical problems in the prior art, such as poor dispersion stability of nano-calcium carbonate in coating solution, the single protective mechanism of simple oil coating, and the difficulty in scaling up the calcium carbonate mineralization coating process.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a gastrointestinal-coated probiotic granule, characterized in that it comprises a probiotic core material and a coating layer covering the core material; wherein the coating layer is formed of a composite coating material of hydrogenated palm oil and stearic acid-modified nano-active calcium carbonate, wherein the stearic acid-modified nano-active calcium carbonate accounts for 50% to 60% of the total mass of the composite coating material, and the weight ratio of the coating layer to the core material is 20% to 25%.

[0009] Furthermore, the average particle size of the stearic acid-modified nano-active calcium carbonate is 100 nm.

[0010] Furthermore, the probiotics are selected from one or more of Bifidobacterium lactis, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Lactobacillus plantarum.

[0011] A method for preparing the above-mentioned enteric-coated probiotic granules is also disclosed, comprising the following steps:

[0012] S1. Preparation of probiotic core material: Probiotic powder and microcrystalline cellulose are mixed at a mass ratio of 1:1, and probiotic granules with a particle size of 200-500 μm are prepared by swing granulation technology. S2. Hydrogenated palm oil is heated and melted, and stearic acid-modified nano-activated calcium carbonate is added under stirring and dispersed evenly to obtain a coating solution; the mass percentage of stearic acid-modified nano-activated calcium carbonate in the coating solution is 50% to 60%. S3. The core material is placed in a fluidized bed, and the coating liquid is sprayed onto the surface of the core material to form a coating layer, thus obtaining the coating. The inlet air temperature of the fluidized bed is 35-45°C, the spray temperature of the coating liquid is 60-65°C, the atomization pressure is 30-35 MPa, and the coating weight gain is 20%-25%.

[0013] In step S3, a bottom-spray fluidized bed coating device is used to heat the obtained coating liquid to 65°C, maintain it in a molten state, and continuously stir it. The liquid is then sprayed onto the surface of the obtained probiotic granule core material through an atomizing nozzle. Process parameters: inlet air temperature 35–45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to a rotational speed of 13 r / min, and fan frequency 30 Hz. The coating weight gain is 20–25%. After coating, the mixture is cooled to room temperature to obtain enterosoluble probiotic granules. Preferably, the melting point of the hydrogenated palm oil is 58–65°C.

[0014] Furthermore, the probiotic core material mentioned in step S1 is obtained by granulating a mixture of probiotic powder and microcrystalline cellulose at a mass ratio of 1:1, with a particle size of 200-500 μm.

[0015] Preferably, the survival rate of the probiotic particles after treatment in artificial gastric fluid (pH 1.2) for 2 hours is ≥90%, and the release rate after treatment in artificial intestinal fluid (pH 6.8) for 2 hours is not less than 90%.

[0016] Another food, health product, or pharmaceutical preparation is provided, which contains enteric-coated probiotic granules as described above.

[0017] Finally, an application of the above-mentioned enteric-coated probiotic granules in the preparation of foods, health products, or medicines for improving gut health is provided.

[0018] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: This invention uses stearic acid-modified nano-active calcium carbonate, which has hydrophobic properties and good compatibility with molten hydrogenated palm oil. It can achieve stable dispersion at a high concentration of 50% to 60%, and the coating solution shows no visible precipitation after standing for 2 hours. This solves the technical problem of easy aggregation and precipitation of nano-calcium carbonate in polymer coating solutions in the prior art.

[0019] This invention employs a composite coating layer of hydrogenated palm oil and nano-calcium carbonate. The hydrogenated palm oil forms a dense hydrophobic physical barrier, preventing gastric acid penetration; the nano-calcium carbonate slowly neutralizes acidity in the gastric acid environment, generating bubbles to form a microenvironment buffer. The synergistic effect of both significantly improves the survival rate of probiotics in gastric acid. Experiments show that the probiotic particles prepared in this invention have a survival rate of 92.3%–96.4% after treatment in simulated gastric fluid for 2 hours, significantly higher than the 64.3% of the group coated with hydrogenated palm oil alone and the 29.8% of the group coated with acrylic resin alone. Hydrogenated palm oil itself has enteric properties, and it can rapidly disintegrate and release probiotics in the intestinal pH environment. The release rate of the composite coating layer of this invention exceeded 93% after treatment in artificial intestinal fluid for 2 hours, ensuring the effective colonization of probiotics in the intestine.

[0020] This invention employs a fluidized bed bottom spray hot melt coating process, with the inlet air temperature controlled at 35-45℃. The coating process has minimal impact on the activity of probiotics. This process has been widely used in the pharmaceutical and food industries, with a high degree of equipment standardization, good controllability of process parameters, and easy large-scale production.

[0021] The preparation method of this invention is based on a mature fluidized bed coating process, which is easy to industrialize. This coating system is suitable for a variety of water-soluble active ingredients that are easily degraded in the rumen, and has strong versatility. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the probiotic coated granules of the present invention; Figure 2 Comparison of the static stability of coating solutions with different coating formulations (after standing for 5 min and 2 h).

[0023] Figure 3 This is a diagram showing the gas production of the probiotic-coated granules of the present invention after 2 hours of treatment with artificial gastric fluid. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight.

[0026] Unless otherwise specified, the reagents and raw materials used in the embodiments and comparative examples of this invention are commercially available.

[0027] Example 1: Coating resulted in a 20% weight gain, with the coating solution containing 50% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 500g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 500g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0028] (2) Preparation of core material: Mix 500g of Bifidobacterium lactis B94 bacterial powder with 497g of microcrystalline cellulose and 3g of HPMC evenly, add 30% water, and use the swing granulation technology to prepare probiotic granules with a particle size of 200-500μm.

[0029] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0030] Example 2: Coating increased weight by 25%, with the coating solution containing 50% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 500g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 500g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0031] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0032] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 25%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0033] Example 3: Coating resulted in a 20% weight gain, with the coating solution containing 60% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 600g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 400g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0034] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0035] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0036] Comparative Example 1: Coating solution containing 0% nano-calcium carbonate (pure hydrogenated palm oil) This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Hydrogenated palm oil was heated and melted and stored in a water bath at 65°C to obtain coating solution.

[0037] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0038] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0039] Comparative Example 2: Coating with Nano-Calcium Carbonate / Acrylic Resin Ethanol Solution This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 500g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 500g of 10% acrylic resin ethanol solution, stir for 30min until uniformly dispersed to obtain coating solution.

[0040] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0041] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating solution prepared in step (1) was sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle under continuous stirring. Process parameters: inlet air temperature 65℃, outlet air temperature 40℃, atomization pressure 30MPa, peristaltic pump inlet speed corresponding to rotation speed 4 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enteric-coated probiotic granules.

[0042] Comparative Example 3: Coating solution containing 70% nano-calcium carbonate This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: 700g of stearic acid-modified nano-active calcium carbonate (average particle size 100nm) was mixed with 300g of molten hydrogenated palm oil (melting point 62℃) and stirred in a 65℃ water bath for 30min. The results showed that the coating solution had too high viscosity and poor fluidity, and could not pass through the atomizing nozzle (clogged nozzle), resulting in coating failure. This comparative example shows that there is an upper limit threshold for calcium carbonate content.

[0043] Comparative Example 4: Coating weight gain 20%, coating solution containing 20% ​​nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 200g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 800g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0044] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0045] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0046] Comparative Example 5: Coating with ethanol solution of acrylic resin This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Slowly add acrylic resin to ethanol, stirring constantly to help dissolve, until the mass percentage of acrylic resin is 10% to obtain an ethanol coating solution of acrylic resin.

[0047] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0048] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating solution prepared in step (1) was sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle under continuous stirring. Process parameters: inlet air temperature 65℃, outlet air temperature 40℃, atomization pressure 30MPa, peristaltic pump inlet speed corresponding to rotation speed 4 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enteric-coated probiotic granules.

[0049] Comparative Example 6: Coating weight gain 100%, coating solution containing 50% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 500g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 500g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0050] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0051] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 100%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0052] Comparative Example 7: Coating weight gain 15%, coating solution containing 50% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 500g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 500g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0053] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0054] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 15%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0055] Comparative Example 8: Coating weight gain 20%, coating solution containing 40% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 400g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 600g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0056] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis 500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0057] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 20%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0058] Comparative Example 9: Coating weight gain was 25%, and the coating solution contained 40% nano-calcium carbonate. This embodiment provides a fluidized bed coating method for enteric-coated probiotic granules, the specific steps of which are as follows: (1) Preparation of coating solution: Take 400g of stearic acid surface modified nano-active calcium carbonate (average particle size 100nm), mix with 600g of molten hydrogenated palm oil (melting point 62℃), stir in a 65℃ water bath for 30min until uniformly dispersed to obtain coating solution.

[0059] (2) Preparation of core material: Bifidobacterium lactis Bifidobacterium lactis500g of B94 bacterial powder, 497g of microcrystalline cellulose, and 3g of HPMC are mixed evenly, and 30% water is added. The mixture is then prepared into probiotic granules with a particle size of 200-500 μm using a swing granulation technique.

[0060] (3) Fluidized bed coating: A bottom-spray fluidized bed coating device was used. The coating liquid prepared in step (1) was heated to 65°C and kept in a molten state while being continuously stirred. It was then sprayed onto the surface of 1 kg of probiotic granule core material prepared in step (2) through an atomizing nozzle. Process parameters: inlet air temperature 35-45°C, outlet air temperature 32°C, atomization pressure 30 MPa, peristaltic pump inlet speed corresponding to rotation speed 13 r / min, fan frequency 30 Hz. The coating weight gain was 25%. After coating, the mixture was cooled to room temperature to obtain enterosoluble probiotic granules.

[0061] Example 1: In vitro simulated gastric acid neutralization test Four 50 mL aliquots of artificial gastric fluid were taken from each treatment group and placed in separate 100 mL Erlenmeyer flasks. The flasks were preheated at 37°C with constant shaking (100 rpm) for 10 min. 2.0 g of the test sample was added to each flask, and timing was started simultaneously. A 0.2 g nano-calcium carbonate sample was used as a control group. At 0, 0.25, 0.5, 1, and 2 h, 2 mL samples were quickly taken and the pH value was measured using a pH meter. Samples were discarded after each measurement to avoid contamination. The results are shown in Table 1.

[0062]

[0063] The probiotic granules prepared in Examples 1-3 of this invention all showed an increase in pH after being treated in simulated gastric juice for 2 hours, indicating that the nano-calcium carbonate in the coating played a buffering role in the acidic gastric environment, reducing the destructive effect of gastric juice on probiotics; Comparative Examples 1, 2, 4, 5, 7, and 8 showed relatively small changes in gastric juice pH. Comparative Example 3 could not be coated due to the poor fluidity of the coating solution, indicating that there is an upper limit to the calcium carbonate content in the coating solution.

[0064] Example 2: Evaluation of in vitro release performance Artificial gastric fluid (pH 1.2) was prepared according to the method in General Chapter 0931 of the 2020 edition of the Chinese Pharmacopoeia. 2 g of each sample (Example 1 and Comparative Examples 1 and 3) was added to 50 mL of artificial gastric fluid and incubated at 37°C with shaking. Samples were taken at 0 h, 1 h, and 2 h, and the viable bacterial count was determined using the plate count method to calculate the survival rate. The results are shown in Table 2.

[0065]

[0066] The results showed that the probiotic particles prepared in Examples 1-3 of this invention had a survival rate of ≥92% after treatment in artificial gastric fluid for 2 hours, which was superior to the comparative examples (Comparative Example 1: only 64.3%, Comparative Example 4: only 73.5%, Comparative Example 8: only 80.1%). Example 1, coated with high-concentration nano-calcium carbonate, had a higher survival rate than Comparative Example 1 (without nano-calcium carbonate), Comparative Example 4 (with low-concentration nano-calcium carbonate), and Comparative Example 2 (coated with a mixture of acrylic resin and nano-calcium carbonate). This is because, in this invention, hydrogenated palm oil forms a physical barrier while nano-calcium carbonate slowly neutralizes acidity in gastric acid (CaCO3 + 2HCl → CaCl2 + CO2 + H2O), generating carbon dioxide bubbles to form a microenvironment buffer. The synergistic effect of both effectively protects the probiotics. Comparative Example 3 was not tested due to coating failure. Although Comparative Example 6 had a high survival rate, its subsequent intestinal fluid release performance was poor (see Table 3). The survival rates of Comparative Examples 7 and 8 were not higher than 80.1%, indicating that 20%–25% coating weight gain and 50%–60% calcium carbonate content are key to achieving high survival rates.

[0067] Example 3: Evaluation of Artificial Intestinal Fluid Release Performance Following the method in General Chapter 0931 of the 2020 edition of the Chinese Pharmacopoeia, artificial intestinal fluid (pH 6.8) was prepared. Samples treated with artificial gastric fluid for 2 hours were transferred to the artificial intestinal fluid and incubated at 37℃ with shaking. Samples were taken at 0h, 0.5h, 1h, and 2h to determine the probiotic release rate. The results are shown in Table 3. Figure 3 As shown.

[0068]

[0069] The results showed that the probiotic particles prepared in Examples 1-3 of this invention all had a release rate of ≥93% after being treated in artificial intestinal fluid for 2 hours, comparable to Comparative Examples 2, 5, 7, and 8, and superior to the 88.5% of Comparative Example 1. The combination of nano-calcium carbonate and hydrogenated palm oil, used as an enteric coating material, could rapidly disintegrate under the pH environment of the intestine, ensuring the effective release of probiotics. Comparative Example 6 experienced intestinal release obstruction due to excessively thick coating, indicating that the coating weight gain should not be too high. Although Comparative Example 5 had a high release rate, its gastric fluid survival rate was extremely low, resulting in poor overall performance. Comparative Example 7 had a high release rate, but its gastric fluid survival rate was only 77.2%, which was also unsatisfactory. Considering both gastric fluid survival rate and intestinal fluid release rate, Examples 1-3 of this invention achieved the optimal balance.

[0070] The fluidized bed coating method for enteric-coated probiotic granules provided by this invention features mild process conditions, simple operation, and suitability for large-scale industrial production. The prepared probiotic granules exhibit excellent gastric acid tolerance and enteric release properties, and can be directly used to prepare foods, health products, or drugs that improve intestinal health, showing broad application prospects.

[0071] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 type of enteric-coated probiotic granules, characterized in that, It includes a probiotic core material and a coating layer covering the core material; wherein the coating layer is formed of a composite coating material of hydrogenated palm oil and stearic acid surface-modified nano-active calcium carbonate, wherein the stearic acid surface-modified nano-active calcium carbonate accounts for 50% to 60% of the total mass of the composite coating material, and the weight ratio of the coating layer to the core material is 20% to 25%.

2. The enteric-coated probiotic granules according to claim 1, characterized in that, The average particle size of the stearic acid-modified nano-active calcium carbonate is 100 nm.

3. The enteric-coated probiotic granules according to claim 1, characterized in that, The probiotics are selected from one or more of Bifidobacterium lactis, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Lactobacillus plantarum.

4. A method for preparing enteric-coated probiotic granules according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of probiotic core material; S2. Hydrogenated palm oil is heated and melted, and stearic acid-modified nano-activated calcium carbonate is added under stirring and dispersed evenly to obtain a coating solution; the mass percentage of stearic acid-modified nano-activated calcium carbonate in the coating solution is 50% to 60%. S3. The core material is placed in a fluidized bed, and the coating liquid is sprayed onto the surface of the core material to form a coating layer, thus obtaining the coating. The inlet air temperature of the fluidized bed is 35-45°C, the spray temperature of the coating liquid is 60-65°C, the atomization pressure is 30-35 MPa, and the coating weight gain is 20%-25%.

5. The preparation method according to claim 4, characterized in that, The probiotic core material mentioned in step S1 is obtained by granulating a mixture of probiotic powder and microcrystalline cellulose at a mass ratio of 1:1, with a particle size of 200-500 μm.

6. A food, health product, or pharmaceutical preparation, characterized in that, It contains enteric-coated probiotic granules as described in any one of claims 1-3.

7. The use of the enteric-coated probiotic granules according to any one of claims 1-3 in the preparation of food, health products or medicines for improving intestinal health.

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