A device for continuous preparation of probiotic microcapsules and a method for preparing the same

Abstract

The present application belongs to the field of probiotic embedding technology, and relates to a continuous preparation device for probiotic microcapsules, comprising a reactor, a membrane filter, a blending tank and a spray dryer connected in sequence; the top of the reactor and the blending tank is respectively provided with a feeding port, and the outer wall of the side wall is wrapped with a sandwich layer for feeding medium, a medium inlet is formed in the sandwich layer side wall and located below, and a medium outlet is formed in the other side wall and located above; a driving motor is connected to the reactor and the blending tank, and the driving motor is connected with a stirrer; the top of the reactor is further provided with a mounting port for mounting a pH meter, and the top of the blending tank is further provided with a feeding port; a discharge port is formed below the spray dryer. The preparation method is also disclosed, and a continuous production method of layer-by-layer aggregation is adopted, the method combines layer-by-layer aggregation embedding to form gel microspheres, and then secondary embedding prebiotics is carried out to prepare a continuous production process of probiotic powder.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of probiotic embedding, and relates to a continuous preparation device for probiotic microcapsules and a preparation method thereof. BACKGROUND

[0002] Probiotics, a word derived from Greek, means "symbiosis" and is opposite to antibiotic. It refers to single or mixed active microbial preparations applied in animals and human bodies to improve the microecological balance in the bodies and promote the health of the hosts. Probiotics mainly include lactobacillus, bifidobacterium, leuconostoc, propionibacterium, pedioccocus, bacillus, and some molds and yeasts.

[0003] In recent years, probiotics have attracted more and more attention, and more and more researches on probiotics have been conducted. The health care effects of probiotics mainly include prevention or improvement of diarrhea, enhancement of human immunity, promotion of the health of the intestinal digestive system, relief of lactose intolerance, and help in absorption of nutritional ingredients. Studies have shown that, in order to play the role of probiotics, the number of live bacteria must be more than 10 6 cfu / mL or 10 6 cfu / g after passing through the gastrointestinal tract of humans and animals, and the live bacteria enter the small intestine and settle down, so as to play the role of probiotics. However, most probiotics have poor tolerance to gastric acid and bile salts, and even if a large amount of probiotics is orally taken, it is difficult to ensure that enough live bacteria enter the intestinal tract to play a role.

[0004] Microcapsule embedding technology is the most effective method for protecting probiotics from external environment, and has become a research hotspot. Microcapsule technology is a kind of microcapsule technology with a semi-permeable or sealed capsule membrane, which is formed by using natural or synthetic polymer encapsulating materials to coat solid, liquid, or even gaseous small core materials with a diameter of 1-5000 μm (usually between 5-400 μm). The microcapsule technology of coacervation is a process in which one or more hydrophilic colloids are first formed into a coacervate phase in a solution, deposited on the surface of the active material, and then solidified by a bridging agent to form microcapsules. The microcapsule technology of coacervation has the advantages of adjustable size and load range, and high embedding yield. The microcapsule of coacervation has a three-dimensional rigid structure formed by solidification during preparation, enhances the tolerance to the environment, and has controlled release. In addition, the microcapsule is easy to disperse in aqueous solution, which is convenient for subsequent addition and application. Therefore, researches are being conducted on the microcapsule in the fields of drugs, pesticides, and food at home and abroad.

[0005] Currently, much research has been conducted on probiotic microcapsule technology, with commonly used methods including spray drying, freeze drying, extrusion, complexation, emulsification, and electrospinning. While these methods are numerous, each has its advantages and disadvantages. For example, extrusion is difficult to scale up, emulsification suffers from oil consumption issues, spray drying and freeze drying are not strictly encapsulation methods, releasing bacteria relatively quickly, and the high temperatures of spray drying cause significant damage to the bacteria. Freeze drying is costly and also causes cell damage during the process, thus hindering continuous large-scale production. Exploring or improving a method for preparing probiotic microcapsules that is both economical and suitable for large-scale industrial production remains a problem to be solved. Summary of the Invention

[0006] In order to overcome the defects of the existing technology, the purpose of this invention is to provide a continuous preparation device and preparation method for probiotic microcapsules, which solves the problem that it is currently impossible to continuously produce probiotic microcapsules on a large scale.

[0007] This invention is achieved through the following technical solution:

[0008] A continuous preparation apparatus for probiotic microcapsules includes a reactor, a membrane filter, a mixing tank, and a spray dryer connected in sequence; the reactor is used to add wall material, probiotic slurry, and a curing agent, and the mixing tank is used to add prebiotics.

[0009] Both the reactor and the mixing tank are equipped with a feeding port at the top, and the side walls are wrapped with a jacket for introducing the medium. The medium inlet is located on the lower side wall of the jacket, and the medium outlet is located on the upper side wall of the other side wall of the jacket. Both the reactor and the mixing tank are connected to a motor, and the motor is connected to a stirrer.

[0010] The top of the reactor is also equipped with a pH meter mounting port, and the top of the mixing tank is also equipped with a feed inlet.

[0011] The spray dryer has a discharge port at the bottom.

[0012] Furthermore, a first booster pump is installed between the reactor outlet and the membrane filter inlet, a second booster pump is installed between the membrane filter outlet and the mixing tank inlet, and a third booster pump is installed between the mixing tank outlet and the spray dryer inlet.

[0013] Furthermore, the first, second, and third booster pumps are all Roots pumps.

[0014] Furthermore, the agitator employs a double-layered impeller.

[0015] Furthermore, the medium used can be hot water, steam, or cold water.

[0016] Furthermore, both the reactor and the mixing tank are equipped with control panels.

[0017] This invention also discloses a method for preparing the continuous probiotic microcapsule preparation device, comprising the following steps:

[0018] S1. Dissolving wall material: Add gelatin, gum arabic and double-distilled water to the reactor. The total mass concentration of gelatin and gum arabic is 1%-2.5%. The dissolving temperature is controlled at 50-70℃ and stirred. The dissolving time is 0.5-2h. During the dissolving process, heat medium is introduced into the jacket from bottom to top.

[0019] After the wall material has completely dissolved, lower the temperature of the reaction system to below 40°C.

[0020] S2, Layer-by-Layer Coagulation Reaction: Activated bacterial sludge is added to the reactor at a concentration of 1%-1.5% of the total reaction solution concentration, resulting in a probiotic concentration of 1×10⁻⁶. 9 cfu / mL or higher;

[0021] Adjust the reaction temperature to 35-42℃, stir continuously, add acidic solution dropwise, adjust the pH to 3.7-4.2, react for 35-60 minutes, and obtain the reactant, which is the one-time encapsulation body;

[0022] S3. Cooling: After the layer-by-layer coagulation reaction is completed, the reactants in the reactor are cooled for 20-40 minutes, and the temperature is controlled to below 15°C.

[0023] S4. Solidification of reactants: Adjust the pH of the reaction system in the reactor to 5-8, and then add transglutaminase for solidification. The amount of transglutaminase added is 8-20 enzyme activity units / gram of gelatin protein, and the solidification time is 3-8 hours to obtain solidified wet capsule products.

[0024] S5. Membrane filtration: The solidified wet bladder product enters the membrane filter for partial dehydration treatment to obtain wet bladders with a solid content of 20%-25%.

[0025] S6. Blending process: Add the membrane-filtered wet capsules to the blending tank, add prebiotics to the blending tank, control the content of solids in the blending tank to 35%-50%, and control the temperature to 50-60℃ to obtain the blended microcapsules.

[0026] S7. Spray drying: The prepared microcapsules are put into a spray dryer and dried to obtain probiotic microcapsule powder coated with prebiotics.

[0027] Furthermore, in S2, the specific preparation process of the activated mycelium sludge is as follows:

[0028] First, sterilize the containers and solutions used for activating the bacterial strain at 121°C for 20 minutes.

[0029] The cryopreserved bacterial strain was inoculated into MRS liquid medium, anaerobic cultured for 24 h, and passaged 3 times to fully activate it.

[0030] Transfer 10% of the inoculum to 500 mL of MRS liquid medium and carry out proliferation culture under anaerobic conditions. After 18 h, the bacterial suspension in the late logarithmic phase is centrifuged at 4 °C and 4000 r / min for 10 min, the supernatant is removed, the bacterial sludge is washed twice with sterile NaCl solution, and then resuspended in 10 mL of physiological saline to obtain concentrated bacterial solution.

[0031] The concentrated bacterial solution was centrifuged to obtain bacterial sludge.

[0032] Furthermore, in S1, the process of lowering the temperature of the reaction system to below 40°C is as follows: stop adding fuel to the reactor, and simultaneously introduce a cooling medium into the jacket from bottom to top.

[0033] Furthermore, in S7, the inlet temperature of the spray dryer is controlled at 180-220℃, and the outlet temperature is controlled at 70-90℃.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] This invention discloses a continuous probiotic microcapsule preparation device, comprising a reactor, a membrane filter, a mixing tank, and a spray dryer connected in sequence. Within the reactor, the wall material is dissolved, and a layer-by-layer coagulation reaction between the wall material and the probiotic slurry is completed, followed by a solidification reaction, achieving initial encapsulation of probiotics by the wall material. This multi-functional device saves costs. The initially encapsulated probiotics then enter the mixing tank, where, under stirring, a wall material containing prebiotic functional factors is added as a secondary encapsulation material. Finally, spray drying is used to further encapsulate the prebiotics onto the surface of the gel microspheres, forming a secondary encapsulation. Due to the indigestibility of prebiotics, they can effectively pass through gastric acid and bile salts, reaching the small intestine. The encapsulated probiotics are released in the small intestine due to enzymatic action and utilized by intestinal probiotics, thus promoting probiotic growth. This preparation device has a simple structure, realizes continuous production of probiotic microcapsules, and can be widely applied.

[0036] This invention also discloses a continuous preparation method for probiotic microcapsules. First, a layer-by-layer aggregation method is used to initially encapsulate probiotics. This involves encapsulating the probiotics within macromolecules through electrostatic adsorption, forming microspheres (microgels) that allow the probiotics to colonize. This not only prevents the probiotics from being affected by the external environment but also creates an oxygen-isolated microenvironment, which is highly beneficial for anaerobic or facultative anaerobic bacteria. The resulting capsules also have a controlled-release effect, effectively reaching the small intestine for release compared to unencapsulated probiotics. After layer-by-layer aggregation, a solidification process allows the formed microspheres to develop a more stable three-dimensional structure, making them more stable, especially against heat and humidity, and facilitating secondary encapsulation during spray drying. Under stirring, a wall material containing prebiotic functional factors is added as a secondary encapsulation material. A concentration process is used to achieve a solid content of 35%-50% or higher. The product is then dried in a spray dryer to obtain the microcapsule powder product. Currently, there is no continuous production method using layer-by-layer coagulation, which combines layer-by-layer coagulation and encapsulation to form gel microspheres, and then uses a secondary encapsulation of prebiotics to produce probiotic powder in a continuous production process. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of a continuous probiotic microcapsule preparation device according to the present invention;

[0038] Figure 2 This is a schematic diagram of the reactor structure of the present invention;

[0039] Figure 3 This is a schematic diagram of the mixing tank of the present invention.

[0040] Wherein: 1 is the reactor, 2 is the membrane filter, 3 is the mixing tank, 4 is the spray dryer, 5 is the first booster pump, 6 is the second booster pump, and 7 is the third booster pump;

[0041] 11 is the interlayer, 12 is the pH meter, 13 is the feed port, 14 is the motor, 15 is the medium inlet, 16 is the medium outlet; 31 is the feed port; 41 is the discharge port. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings:

[0043] like Figures 1-3As shown, this invention discloses a continuous probiotic microcapsule preparation device, comprising a reactor 1, a membrane filter 2, a mixing tank 3, and a spray dryer 4 connected in sequence; the reactor 1 is used to add wall material, probiotic slurry, and a curing agent, while the mixing tank 3 is used to add prebiotics; both the reactor 1 and the mixing tank 3 have feeding ports 13 at their tops, and their side walls are wrapped with jackets 11 for introducing a medium. A medium inlet 15 is located on the lower side wall of the jacket 11, and a medium outlet 16 is located on the upper side wall of the jacket 11; both the reactor 1 and the mixing tank 3 are connected to motors 14, and the motors 14 are connected to a stirrer; the spray dryer 4 has a discharge port 41 at its bottom. Figure 2 As shown, the top of reactor 1 is also equipped with a mounting port for installing a pH meter 12, such as... Figure 3 As shown, the top of the mixing tank 3 is also provided with a feed inlet 31.

[0044] like Figure 1 As shown, a first booster pump 5 is provided between the outlet of reactor 1 and the inlet of membrane filter 2, a second booster pump 6 is provided between the outlet of membrane filter 2 and the inlet 31 of mixing tank 3, and a third booster pump 7 is provided between the outlet of mixing tank 3 and the inlet of spray dryer 4.

[0045] Even better, the mixer uses double-layer blades, with one layer of blades near the middle of the mixing rod and the other layer of blades located at the bottom of the mixing rod.

[0046] Specifically, the medium used is hot water, steam, or cold water. Hot water or steam is used for heat preservation, and cold water is introduced for cooling.

[0047] Specifically, the first booster pump 5, the second booster pump 6, and the third booster pump 7 are all Roots pumps.

[0048] Specifically, both reactor 1 and mixing tank 3 are equipped with operation panels, which can be used to set parameters and observe temperature and time.

[0049] The present invention also discloses a method for preparing the continuous probiotic microcapsule preparation device, and specific embodiments are given below.

[0050] Example 1

[0051] A method for preparing a continuous probiotic microcapsule preparation device includes the following steps:

[0052] S1. Dissolving wall material: Add double-distilled water and wall material to reactor 1. The wall material is gelatin and gum arabic, with a concentration of 1% for each. The dissolving temperature is controlled at 50℃ and stirred. The dissolving time is 2 hours. During the dissolving process, hot water is simultaneously introduced into the jacket 11 from bottom to top to keep it warm.

[0053] After the wall material has completely dissolved, lower the temperature of the reaction system to below 40°C.

[0054] S2. Layer-by-layer coagulation reaction: The encapsulated probiotic is *Lactobacillus plantarum*. The activated bacterial sludge is added to reactor 1 at a concentration of 1% of the reaction solution, ensuring a bacterial concentration of 1×10⁻⁶ in the reaction solution. 9 cfu / mL or higher;

[0055] The reaction temperature was adjusted to 35℃, and the mixture was stirred continuously. An acidic solution was added dropwise to adjust the pH to 3.7. The reaction was carried out for 35 minutes to obtain a single-encapsulation capsule.

[0056] S3. Cooling: After the layer-by-layer coagulation reaction is completed, the reactants in reactor 1 are cooled for 20 minutes, and the temperature is controlled to be below 10°C.

[0057] S4. Solidification of reactants: Adjust the pH of the reaction system in reactor 1 to 5, and then add transglutaminase for solidification. The amount of transglutaminase added is 13 enzyme activity units / gram of gelatin protein. Solidify for 8 hours to obtain solidified wet capsule products.

[0058] S5. Membrane filtration: The above-mentioned wet bladder product enters the membrane filter 2 for partial dehydration treatment to obtain a wet bladder with a content of about 20%.

[0059] S6. Blending process: Add the membrane-filtered wet capsules to blending tank 3, add prebiotics to blending tank 3, control the solid content of blending tank 3 to 35%, and control the temperature to 50℃.

[0060] S7. Spray drying: The prepared microcapsules are fed into spray dryer 4. The inlet temperature of spray dryer 4 is controlled at 180℃ and the outlet temperature is controlled at 70℃. After drying, probiotic microcapsule powder coated with prebiotics is obtained.

[0061] Example 2: A method for preparing a continuous probiotic microcapsule preparation device, comprising the following steps:

[0062] S1. Dissolving wall material: Add double-distilled water and wall material to reactor 1. The wall material is gelatin and gum arabic, with a concentration of 1% for each. The dissolving temperature is controlled at 60°C and stirred. The dissolving time is 1 hour. During the dissolving process, steam is simultaneously introduced into the jacket 11 from bottom to top.

[0063] After the wall material has completely dissolved, lower the temperature of the reaction system to below 40°C.

[0064] S2. Layer-by-layer coagulation reaction: The encapsulated probiotic is Lactobacillus reuteri. The activated bacterial sludge is added to reactor 1 at a concentration of 1.5% of the reaction solution, so that the bacterial concentration in the reaction solution reaches 1×10⁻⁶. 9 cfu / mL or higher;

[0065] The reaction temperature was adjusted to 42℃, and the mixture was stirred continuously. An acidic solution was added dropwise to adjust the pH to 4.2. The reaction was carried out for 60 minutes to obtain a single-encapsulation capsule.

[0066] S3. Cooling: After the layer-by-layer coagulation reaction is completed, the reactants in reactor 1 are cooled for 40 minutes, and the temperature is controlled to be below 15°C.

[0067] S4. Solidification of reactants: Adjust the pH of the reaction system in reactor 1 to 8, and then add transglutaminase for solidification. The amount of transglutaminase added is 15 enzyme activity units / gram of gelatin protein, and the solidification time is 3 hours to obtain solidified wet capsule products.

[0068] S5. Membrane filtration: The above-mentioned wet bladder product enters the membrane filter 2 for partial dehydration treatment to obtain a wet bladder with a content of about 25%.

[0069] S6. Blending process: Add the membrane-filtered wet capsules to blending tank 3, add prebiotics to blending tank 3, control the solid content of blending tank 3 to 50%, and control the temperature to 60℃.

[0070] S7. Spray drying: The prepared microcapsules are put into spray dryer 4. The inlet temperature of spray dryer 4 is controlled at 220℃ and the outlet temperature is controlled at 90℃. After drying, prebiotic-encapsulated probiotic microcapsule powder is obtained.

[0071] Example 3

[0072] A method for preparing a continuous probiotic microcapsule preparation device includes the following steps:

[0073] S1. Dissolving the wall material: Add double-distilled water and wall material to reactor 1. The wall material is gelatin and gum arabic, with a concentration of 0.5% for each. The dissolving temperature is controlled at 70°C and stirred. The dissolving time is 2 hours. During the dissolving process, hot steam is simultaneously introduced into the jacket 11 from bottom to top.

[0074] After the wall material has completely dissolved, lower the temperature of the reaction system to below 40°C.

[0075] S2. Layer-by-layer coagulation reaction: The encapsulated probiotic is Lactobacillus reuteri. The activated bacterial sludge is added to reactor 1 at a concentration of 1% of the reaction solution, so that the bacterial concentration in the reaction solution reaches 1×10⁻⁶. 9cfu / mL or higher;

[0076] The reaction temperature was adjusted to 40℃, and the mixture was stirred continuously. An acidic solution was added dropwise to adjust the pH to 4. The reaction was carried out for 50 minutes to obtain a single-encapsulation capsule.

[0077] S3. Cooling: After the layer-by-layer coagulation reaction is completed, the reactants in reactor 1 are cooled for 30 minutes, and the temperature is controlled to be below 15°C.

[0078] S4. Solidification of reactants: Adjust the pH of the reaction system in reactor 1 to 8, and then add transglutaminase for solidification. The amount of transglutaminase added is 17 enzyme activity units / gram of gelatin protein, and the solidification time is 5 hours to obtain solidified wet capsule products.

[0079] S5. Membrane filtration: The above-mentioned wet bladder product enters the membrane filter 2 for partial dehydration treatment to obtain a wet bladder with a content of about 20%.

[0080] S6. Blending process: Add the membrane-filtered wet capsules to blending tank 3, add prebiotics to blending tank 3, control the solid content of blending tank 3 to 40%, and control the temperature to 55℃.

[0081] S7. Spray drying: The prepared microcapsules are put into spray dryer 4. The inlet temperature of spray dryer 4 is controlled at 200℃ and the outlet temperature is controlled at 80℃. After drying, probiotic microcapsule powder coated with prebiotics is obtained.

[0082] Prebiotics can be selected from galactooligosaccharides, fructooligosaccharides, xylo-oligosaccharides, and resistant starch.

[0083] Microencapsulation of probiotics has two characteristics compared to other types of core materials: (1) Since the size of probiotics is usually between 1μm and 5μm, nano-encapsulation technology is not suitable for this field; (2) During the encapsulation process, it is necessary to ensure that the probiotics are still alive.

[0084] The specific process for preparing the activated mycelium sludge is as follows:

[0085] First, sterilize the containers and solutions used for activating the bacterial strain at 121°C for 20 minutes.

[0086] The cryopreserved bacterial strain was inoculated into MRS liquid medium and anaerobic cultured at 35℃ (for embedding Lactobacillus plantarum) or 42℃ (for Lactobacillus reuteri) for 24 h, and then passaged 3 times to fully activate it.

[0087] Transfer 10% of the inoculum to 500 mL of MRS liquid medium and carry out proliferation culture under anaerobic conditions. After 18 h, the bacterial suspension in the late logarithmic phase is centrifuged at 4 °C and 4000 r / min for 10 min, the supernatant is removed, the bacterial sludge is washed twice with sterile NaCl solution, and then resuspended in 10 mL of physiological saline to obtain concentrated bacterial solution.

[0088] The concentrated bacterial solution was centrifuged to obtain bacterial sludge.

[0089] Effect verification:

[0090] I. Study on in vitro release characteristics

[0091] (1) Preparation of artificial gastric juice (SGF) and artificial intestinal juice (SIF)

[0092] SGF consists of sodium chloride (2 g / L), hydrochloric acid (0.008 L / L), and pepsin (3.2 g / L), with the pH adjusted to 1.2 using hydrochloric acid.

[0093] SIF is composed of sodium hydroxide (1.81 g / L), potassium dihydrogen phosphate (8.09 g / L), trypsin (4.76 g / L) and bile salts (5.16 g / L), with the pH adjusted to 7.4 using sodium hydroxide.

[0094] (2) Release characteristics of microcapsules

[0095] Two grams of the microcapsule samples prepared in Examples 1-3 were added to 100 mL of SGF or SIF, stirred thoroughly, and then dispensed into small test tubes. The tubes were placed in a constant-temperature shaker at 37°C with a shaking rate of 100 r / min. Sampling time in SGF was 3 h, and in SIF, it was 6 h. Colony counting was performed after sampling, and the survival rate was calculated. As shown in Table 1, it can be seen that, through in vitro simulation of the gastrointestinal digestive system, the microcapsules formed by the two probiotics (Lactobacillus plantarum and Lactobacillus reuteri) after secondary encapsulation exhibited tolerance to gastric acid and bile salts (survival rates both higher than 90%), thus possessing controlled-release properties. In contrast, the survival rates of the two unencapsulated probiotics under the same conditions were both below 70% for SGF and SIF.

[0096] Survival rate (%) = (M1) / (M0) × 100

[0097] In the formula:

[0098] M1 represents the colony count (cfu / mL) after lg treatment;

[0099] M0 is the initial colony count (cfu / mL) of lg;

[0100] Table 1. Encapsulation efficiency and retention rate of secondary encapsulated microcapsules in in vitro release assays.

[0101]

[0102] II. Results of Microcapsule Encapsulation Efficiency

[0103] Two grams of microcapsule samples prepared in Examples 1-3 were taken and their encapsulation efficiency was tested. The results are shown in Table 2. In Example 1, the encapsulated probiotic was *Lactobacillus plantarum*, while in Examples 2 and 3, *Lactobacillus reuteri* was encapsulated. The encapsulation efficiency of *Lactobacillus plantarum* was 87%, while that of *Lactobacillus reuteri* was higher than 90%, indicating that this method can effectively encapsulate probiotics.

[0104] Encapsulation rate % = Amount of probiotics encapsulated in the capsule / Amount of added probiotics

[0105] Table 2 Encapsulation rate of probiotics

[0106] Group / probiotic Lactobacillus plantarum Lactobacillus reuteri Example 1 87％ Example 2 94％ Example 3 92％

[0107] The gel microspheres prepared by the layer-by-layer coagulation method used in this invention have the ability to isolate oxygen and light, and provide good protection for anaerobic and facultative anaerobic bacteria during preparation and storage. These gel microspheres also exhibit resistance to gastric acid and bile salts. Furthermore, through solidification, the three-dimensional network structure of the gel microspheres can be further enhanced, further increasing their resistance to high temperatures and humidity.

[0108] Layer-by-layer coagulation microencapsulation technology involves one or more hydrophilic colloids first forming a coagulated phase in solution, which then deposits on the surface of probiotic material, followed by solidification with a bridging agent to form microcapsules (this option is optional). Layer-by-layer coagulation encapsulation technology has several advantages: firstly, the preparation temperature is low, typically not exceeding 40℃; secondly, it offers advantages such as a wide range of adjustable microcapsule size and loading capacity, and high encapsulation yield; and thirdly, it provides controlled release. By employing layer-by-layer coagulation combined with spray drying for secondary encapsulation of probiotics, their survival rate can be improved, protecting them from adverse external environmental influences and enabling sustained release within the intestines.

[0109] The prepared gel microspheres are the first layer of microcapsules. By further adding prebiotics to the solution of the gel microspheres and using spray drying, the prebiotics are encapsulated on the surface of the gel microspheres to form a secondary encapsulation. Due to the indigestibility and non-absorption of prebiotics by the human body, they can effectively pass through gastric acid and bile salts and reach the small intestine. The encapsulated probiotics are released and utilized by intestinal probiotics in the small intestine due to the action of enzymes, which plays a role in increasing the number of probiotics.

Claims

1. A method for the continuous production of probiotic microcapsules, characterized in that, The probiotic microcapsule continuous preparation device comprises a reactor (1), a membrane filter (2), a blending tank (3) and a spray dryer (4) connected in sequence; the reactor (1) is used for adding wall materials, probiotic slurry and solidifying agents, and the blending tank (3) is used for adding prebiotics; The top of the reactor (1) and the blending tank (3) is provided with a feeding port (13), and the outer wall is wrapped with a sandwich (11) for introducing a medium; a medium inlet (15) is formed in the side wall of the sandwich (11) and located below; a medium outlet (16) is formed in the other side wall of the sandwich (11) and located above; a motor (14) is connected to the reactor (1) and the blending tank (3); and the motor (14) is connected with a stirrer; The top of the reactor (1) is also provided with a mounting port for mounting a pH meter (12), and the top of the blending tank (3) is also provided with a feeding port (31); The lower part of the spray dryer (4) is provided with a discharge port (41); The probiotic microcapsule continuous preparation method comprises the following steps: S1, dissolving wall materials: adding gelatin, gum arabic and double distilled water into the reactor (1), the total mass concentration of gelatin and gum arabic is 1%-2.5%, the dissolving temperature is controlled at 50-70℃, and stirring is carried out, the dissolving time is 0.5-2h, and hot medium is introduced from bottom to top in the sandwich (11) of the reactor (1) during the dissolving process; After the wall materials are dissolved, the temperature of the reaction system is reduced to below 40℃; S2, layer-by-layer condensation reaction: the activated slurry is added to the reactor (1), and the amount of the slurry added is 1%-1.5% of the total reaction solution concentration, so that the concentration of probiotics in the reaction solution reaches 1×10 9 cfu / mL or more; The reaction temperature is adjusted to 35-42℃, and the pH is adjusted to 3.7-4.2 by continuously adding an acidic solution, and the reaction is carried out for 35-60 minutes to obtain the reaction product, i.e. the first embedding capsule body; S3, cooling: after the layer-by-layer condensation reaction is completed, the reaction product in the reactor (1) is cooled, the cooling time is 20-40 minutes, and the temperature is controlled to below 15℃; S4, solidification of the reaction product: adjusting the pH of the reaction system in the reactor (1) to 5-8, and then adding transglutaminase for solidification, the amount of transglutaminase added is 8-20 enzyme activity units / g of gelatin protein, the solidification time is 3-8 hours, and the solidified wet capsule product is obtained; S5, membrane filtration: the solidified wet capsule product enters the membrane filter (2) for partial dewatering treatment, and a wet capsule with a solid content of 20%-25% is obtained; S6, blending treatment: the wet capsule after membrane filtration is added into the blending tank (3), prebiotics are added into the blending tank (3), the solid content of the blending tank (3) is controlled to be 35%-50%, and the temperature is controlled at 50-60℃, to obtain the microcapsule after blending treatment; S7, spray drying: the microcapsule after blending treatment enters the spray dryer (4), and the probiotic microcapsule powder coated with prebiotics is obtained after drying.

2. The method of claim 1, wherein the method is a continuous process. In S2, the preparation process of the activated slurry is as follows: First, the utensils and solutions used for activating the bacteria are sterilized at 121℃ for 20 min; The frozen and preserved bacteria are inoculated into the MRS liquid medium and anaerobically cultured for 24 h, and are subcultured for 3 times to completely activate them; The bacteria were inoculated into 500 mL of MRS liquid medium at an inoculation amount of 10% and proliferated under anaerobic conditions; after 18 h, the bacteria suspension in the late logarithmic phase was centrifuged at 4 ℃ and 4000 r / min for 10 min, the supernatant was removed, the bacteria mud was washed twice with sterile NaCl solution, and then resuspended in 10 mL of normal saline to obtain a concentrated bacteria solution; The concentrated bacteria solution was centrifuged to obtain the bacteria mud.

3. The method of claim 1, wherein the method is a continuous process. In S1, the process of reducing the temperature of the reaction system to below 40℃ is: stopping the addition of the reactor (1), and at the same time, passing a cooling medium from bottom to top into the interlayer (11).

4. The method of claim 1, wherein the method is a continuous process. In S7, the inlet temperature of the spray dryer (4) is controlled at 180-220℃, and the outlet temperature is controlled at 70-90℃.

5. The method of claim 1, wherein the method is a continuous process. A first booster pump (5) is arranged between the outlet of the reactor (1) and the inlet of the membrane filter (2), a second booster pump (6) is arranged between the outlet of the membrane filter (2) and the inlet (31) of the blending tank (3), and a third booster pump (7) is arranged between the outlet of the blending tank (3) and the inlet of the spray dryer (4).

6. The method of claim 1, wherein the method is a continuous process. The first booster pump (5), the second booster pump (6) and the third booster pump (7) are all Roots pumps.

7. The method of claim 1, wherein the method is a continuous process. The stirrer adopts double-layer paddles.

8. The method of claim 1, wherein the method is a continuous process. The cooling medium is hot water, steam and cold water.

9. The method of claim 1, wherein the method is a continuous process. Operation panels are arranged on the reactor (1) and the blending tank (3).

Images