Method for preparing high-activity lactic acid bacteria capsule based on lactic acid bacteria protective agent in combination with spray drying technology

Abstract

The invention belongs to the technical field of lactic acid bacteria, and particularly relates to a method for preparing a high-activity lactic acid bacteria capsule based on a lactic acid bacteria protective agent in combination with a spray drying technology. According to the preparation method disclosed by the invention, firstly, lactic acid bacteria are protected by screening a protective agent, and trehalose, xylooligosaccharide and L-ascorbic acid are combined for use, so that a synergistic protection effect can be achieved, damage to the activity and quantity of thalli in a spray drying process is reduced, and the thalli have relatively high activity and viable bacteria quantity; secondly, the lactic acid bacteria are coated in the wall material as a core substance, so that the influence of the external environment is avoided, the lactic acid bacteria are protected, and the use value of the lactic acid bacteria is improved; finally, the influence on the lactic acid bacteria is reduced as much as possible and the activity of the lactic acid bacteria is further improved by combining optimized spray drying conditions, controlling the temperature of an air inlet and an air outlet, relatively reducing the temperature and optimizing a balance point, so that a remarkable technical effect is achieved, and the method has positive significance in production of lactic acid bacteria capsule preparations and market popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of lactic acid bacteria, and particularly relates to a method for preparing high-activity lactic acid bacteria capsules based on a lactic acid bacteria protective agent combined with spray drying technology. Background Art

[0002] Probiotics are living microorganisms that can exert beneficial effects on the host by improving the balance of intestinal microorganisms. Studies have found that probiotics have great physiological effects in regulating the structure of intestinal flora, enhancing the body's immunity, lowering cholesterol, and eliminating carcinogenic factors. At the same time, they are of great significance for the prevention and treatment of some diseases such as diabetes, hypertension, and hyperlipidemia. As people's understanding and research on the health benefits of probiotics continue to deepen, the consumption of probiotic products is increasing day by day. Lactic acid bacteria is a common food-grade probiotic that can ferment carbohydrates into lactic acid, hence the name. Lactic acid bacteria are widely distributed and are usually found in foods such as meat, milk and vegetables and their products. In addition, lactic acid bacteria are also widely present in the intestines of livestock and poultry and a few clinical samples. Among them, lactic acid bacteria in the oral cavity, intestines and other environments of humans and other mammals are important members of the normal microbial flora in specific areas; at the same time, they have many probiotic effects such as improving human health, so they are widely used in the food industry.

[0003] In food industry applications, spray drying technology is the main technical means to produce probiotic powder. Spray drying is a method of applying systematic technology to material drying. After the thin material is atomized in the drying chamber, the water vaporizes rapidly in contact with hot air to obtain a dry product. However, probiotic lactic acid bacteria are sensitive to environmental conditions and have poor stability during food processing and storage. Especially in the spray drying process, probiotics will be damaged by high temperature and dehydration, resulting in damage to cell membrane integrity, protein denaturation, and reduced stability of macromolecules such as ribosomes and RNA, resulting in a significant reduction in the survival rate of probiotics after spray drying. Studies have found that adding protective agents to probiotics during the drying process can reduce damage in the process and maintain the original biological activity of microorganisms as much as possible. Common freeze-drying protective agents include sugars, proteins, and antioxidants, but the protective effect is not ideal, and the biological activity of microorganisms cannot be effectively maintained. Its drying activity needs to be improved. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to solve the problems and provide a method for preparing high-activity lactic acid bacteria capsules based on a lactic acid bacteria protective agent combined with spray drying technology; the present invention first protects the lactic acid bacteria by screening a protective agent, and then prepares a wall material solution, and encapsulates the lactic acid bacteria as a core material in the wall material for secondary protection, thereby protecting them from the influence of the external environment and improving their activity and use value; finally, combined with optimizing the spray drying conditions, the temperatures of the air inlet and the air outlet are controlled to minimize the influence on the lactic acid bacteria, further improve the activity of the lactic acid bacteria, and achieve significant technical effects.

[0005] In order to achieve the above objectives, the present invention adopts the following scheme:

[0006] The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology comprises the following steps:

[0007] (1) Activation of lactic acid bacteria: First, the lactic acid bacteria are cultured and activated in MRS solid medium; then, a single colony of lactic acid bacteria grown in MRS solid medium is selected and inoculated into MRS liquid medium for further culture; after culture, the bacteria are centrifuged to obtain the bacteria, and then washed several times by centrifugation with sterile distilled water, and the bacteria are collected to obtain bacterial mud; finally, the bacteria are dispersed in sterile physiological saline to obtain a lactic acid bacteria suspension, and the concentration of the lactic acid bacteria suspension is not less than 10 10 cells / mL;

[0008] (2) adding trehalose, xylooligosaccharides and L-ascorbic acid into sterile physiological saline to dissolve to obtain a protective agent solution; then mixing the lactic acid bacteria suspension in step (1) with the protective agent solution to obtain a core material solution; wherein the mass concentration of trehalose in the protective agent solution is 2% to 8%, the mass concentration of xylooligosaccharides is 1% to 5%, and the mass concentration of L-ascorbic acid is 0.04% to 0.08%;

[0009] (3) heating the sterile physiological saline to 35-45° C., adding fat, edible gum and polyethylene glycol thereto, cooling to room temperature and performing vacuum degassing to obtain a wall material solution; the polyethylene glycol is PEG 4000, the fat includes walnut oil, camellia oil, olive oil, peanut oil or soybean oil; the edible gum includes gelatin, carrageenan, gellan gum or original gum;

[0010] (4) mixing the core material solution of step (2) and the wall material solution obtained in step (3) to obtain a mixed solution; forming and drying by spray drying to obtain lactic acid bacteria capsules; wherein the air inlet temperature of the spray drying is 75 to 90° C., the air outlet temperature is 45 to 55° C., the vacuum degree is 0.03 to 0.05 MPa, the flow rate is 10 mL / min to 15 mL / min, and the air volume is 2 m 3 / min-4m 3 / min.

[0011] Preferably, the MRS solid culture medium in step (1) has the following components: based on 1 L, beef extract 10.0 g, yeast extract 5.0 g, peptone 10.0 g, glucose 20.0 g, K2HPO4 2.0 g, sodium acetate 5.0 g, MgSO4·7H2O 0.2 g, MnSO4·4H2O 0.05 g, Tween 80 1.0 g, triammonium citrate 2.0 g, agar 15.0 g, and distilled water to 1 L;

[0012] The components of the MRS liquid culture medium are as follows: based on 1 L, beef extract 10.0 g, yeast extract 5.0 g, peptone 10.0 g, glucose 20.0 g, K2HPO4 2.0 g, sodium acetate 5.0 g, MgSO4·7H2O 0.2 g, MnSO4·4H2O 0.05 g, Tween 80 1.0 g, ammonium citrate tribasic 2.0 g, and distilled water to 1 L.

[0013] Preferably, the temperature of the culture activation in step (1) is 35-40°C, and the time is 48-72h; the conditions for inoculating the single colony into the MRS liquid culture medium for further culture are: 180rpm shaking culture, temperature 35-40°C, time 48-72h; the inoculation amount is: 2-3 loops of single colonies are inoculated in every 50mL of MRS liquid culture medium; the washing number is 2-3 times, and the centrifugation conditions are 4°C and 6000rpm.

[0014] Preferably, the lactic acid bacteria in step (1) are Pediococcus acidilactici, which is from China General Microorganism Collection Center with a collection number of CGMCC NO.1.12332.

[0015] Preferably, in step (2), the volume ratio of the lactic acid bacteria suspension and the protective agent solution when mixed is 1:1-2.

[0016] Preferably, in step (2), the mass concentration of trehalose is 4%, the mass concentration of xylo-oligosaccharide is 3%, and the mass concentration of L-ascorbic acid is 0.04%.

[0017] Preferably, in step (3), the dosage of fat, edible gum, polyethylene glycol and sterile saline is in the following relationship: 1-3 mL: 1-2 g: 1.5-3 mL: 10-15 mL.

[0018] Preferably, in step (4), the volume ratio of the core material solution and the material solution when mixed is 1:1.

[0019] Preferably, in step (4), the air inlet temperature of the spray drying is 80°C, and the air outlet temperature is 45°C.

[0020] Beneficial effects of the present invention:

[0021] (1) The lactic acid bacteria used in the present invention are Pediococcus acidilactici, which is a type of microorganism widely used in the food industry and biotechnology field. It has the characteristics of strong acid and high temperature resistance. At the same time, Pediococcus acidilactici has good application value. On the one hand, it helps to improve the nutritional value and shelf life of food. On the other hand, Pediococcus acidilactici can regulate gastrointestinal flora and maintain the balance of intestinal microecology. It is also widely used in the preparation of health supplements and has a positive impact on human intestinal health.

[0022] (2) The present invention is based on the combined use of trehalose, oligoxylose and L-ascorbic acid as protective agents, preferably trehalose and oligoxylose, whose hydrogen bonds can be combined with glycoproteins on the microbial cell membrane, and can also form a vitrified protective shell around the microbial cell membrane to protect the spatial structure of lactic acid bacteria. Compared with other oligosaccharides, oligoxylose has very good stability and is basically not decomposed even when heated to 100°C under acidic conditions (PH = 2.5-7), which can effectively play a protective role.

[0023] (3) The present invention mainly adopts low-temperature spray drying to prepare lactic acid bacteria capsules, combines and optimizes the conditions of spray drying, controls the temperature of the air inlet and outlet, relatively reduces the temperature, optimizes the balance point, minimizes the impact on lactic acid bacteria, and further improves the activity of lactic acid bacteria; the oil, edible gum and polyethylene glycol used as wall material solution can effectively reduce the damage of bacteria during the spray drying process. Moreover, the process of preparation by spray drying is simple to operate, has low production cost, and is suitable for continuous production.

[0024] (4) The present invention provides a method for preparing highly active lactic acid bacteria capsules based on a lactic acid bacteria protective agent combined with spray drying technology. The process of preparation using spray drying is simple to operate, has low production costs, and is suitable for continuous production. Moreover, the activity of the lactic acid bacteria capsules obtained under the combined action of the protective agent and spray drying is as high as 95.13%; and it can maintain a very high survival rate during a long storage period. At 4°C and 90 days, the survival rate of the lactic acid bacteria capsules can still be maintained at 94.61%, achieving significant technical effects. The present invention provides a theoretical research basis for the commercial application of lactic acid bacteria capsules, and has positive significance for the production of lactic acid bacteria capsule preparations and their market promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The effect of different concentrations of trehalose on the survival rate of Pediococcus acidilactici during spray drying;

[0026] Figure 2 The effect of different concentrations of oligoxylan on the survival rate of Pediococcus acidilactici during spray drying;

[0027] Figure 3The effect of different concentrations of L-ascorbic acid on the survival rate of Pediococcus acidilactici during spray drying;

[0028] Note: Different letters represent significant differences (P<0.05). DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] Bacterial strain description: Pediococcus acidilactici was purchased from China General Microorganism Collection Center (CGMCC NO.1.12332), and no self-preservation was involved.

[0032] Medium Description:

[0033] The components of MRS solid culture medium are as follows: per liter, beef extract 10.0 g, yeast extract 5.0 g, peptone 10.0 g, glucose 20.0 g, K2HPO4 2.0 g, sodium acetate 5.0 g, MgSO4·7H2O 0.2 g, MnSO4·4H2O 0.05 g, Tween 80 1.0 g, ammonium citrate tribasic 2.0 g, agar 15.0 g, and distilled water to 1 L.

[0034] The components of MRS liquid culture medium are as follows: per liter, beef extract 10.0 g, yeast extract 5.0 g, peptone 10.0 g, glucose 20.0 g, K2HPO4 2.0 g, sodium acetate 5.0 g, MgSO4·7H2O 0.2 g, MnSO4·4H2O 0.05 g, Tween 80 1.0 g, ammonium citrate tribasic 2.0 g, add distilled water to 1 L.

[0035] Sterile saline: Sterilize the saline solution in an autoclave at 121°C for 15 min.

[0036] Comparative Example 1:

[0037] (1) Activation of lactic acid bacteria: First, the lactic acid bacteria were cultured and activated in MRS solid medium at 37°C for 48 hours; then, a single lactic acid bacteria colony grown in MRS solid medium was selected and inoculated into 50 mL of MRS liquid medium in two loops for further culture, and cultured in a shaking incubator at 180 rpm at 37°C for 48 hours; after culture, the bacteria were centrifuged to obtain the bacteria, and washed three times with sterile distilled water by centrifugation (4°C, 6000 rpm), and the bacteria were collected to obtain bacterial mud; finally, the bacteria were dispersed in sterile physiological saline to obtain a suspension of lactic acid bacteria;

[0038] (2) directly forming and drying the suspension of Pediococcus acidilactici by spray drying to obtain a final product; wherein the air inlet temperature of the spray drying is 100° C., the air outlet temperature is 85° C., the vacuum degree is 0.05 MPa, the flow rate is 10 mL / min, and the air volume is 2 m 3 / min.

[0039] Embodiment 1:

[0040] (1) Activation of lactic acid bacteria: First, the lactic acid bacteria were cultured and activated in MRS solid medium at 37°C for 48 hours; then, a single lactic acid bacteria colony grown in MRS solid medium was selected and inoculated into 50 mL of MRS liquid medium in two loops for further culture, and cultured in a shaking incubator at 180 rpm at 37°C for 48 hours; after culture, the bacteria were centrifuged to obtain the bacteria, and washed three times with sterile distilled water by centrifugation (4°C, 6000 rpm), and the bacteria were collected to obtain bacterial mud; finally, the bacteria were dispersed in sterile physiological saline to obtain a suspension of lactic acid bacteria;

[0041] (2) adding trehalose, xylooligosaccharides and L-ascorbic acid to sterile physiological saline to dissolve to obtain a protective agent solution; then mixing the lactic acid bacteria suspension in step (1) with the protective agent solution at a volume ratio of 1:1 to obtain a core material solution; wherein the mass concentration of trehalose in the protective agent solution is 0%, 2%, 4%, 6% and 8%, the mass concentration of xylooligosaccharides is 1%, and the mass concentration of ascorbic acid is 0.04%;

[0042] (3) 100 mL of sterile physiological saline was heated to 45° C., and then 20 mL of soybean oil, 15 g of edible gelatin, and 20 mL of PEG 4000 were added thereto. After cooling to room temperature, vacuum degassing was performed to obtain a wall material solution;

[0043] (4) mixing the core material solution of step (2) and the wall material solution prepared in step (3) in a volume ratio of 1:1, forming and drying by spray drying, and obtaining a dry product, namely, a lactic acid bacteria capsule; wherein the air inlet temperature of the spray drying is 80° C., the air outlet temperature is 50° C., the vacuum degree is 0.05 MPa, the flow rate is 10 mL / min, and the air volume is 2 m 3 / min.

[0044] The survival rate was calculated according to the formula: survival rate (%) = (n / N) × 100%, where N is the number of live bacteria before drying, and n is the number of live bacteria after drying, and the unit is cfu / g.

[0045] The survival rate of the final product lactic acid bacteria capsule is as follows Figure 1 As shown in the figure, the survival rate significantly increased with the increase of trehalose concentration compared with the group without trehalose addition, reaching the highest value when the trehalose concentration was 4%, and then began to decrease. Therefore, the optimal concentration of trehalose was selected as 4%.

[0046] Embodiment 2:

[0047] The operation is the same as that in Example 1, except that the concentration of trehalose is 4%. The difference is that the mass concentration of xylooligosaccharide is adjusted from 1% to 0, 2%, 3%, 4% and 5% in sequence.

[0048] The survival rate was calculated according to the formula: survival rate (%) = (n / N) × 100%, where N is the number of live bacteria before drying, and n is the number of live bacteria after drying, and the unit is cfu / g.

[0049] The survival rate of the final product is Figure 2 As shown, the results showed that compared with the group without added xylooligosaccharides, the survival rate increased significantly with the increase of trehalose concentration; it reached the highest when the xylooligosaccharide concentration was 3%, and then continued to increase the dosage, the survival rate began to show a downward trend; too high an addition had no promoting effect; therefore, the optimal concentration of xylooligosaccharides was selected as 3%.

[0050] Embodiment 3:

[0051] The operation was the same as in Example 1, except that the mass concentration of trehalose was 4% and the mass concentration of xylo-oligosaccharide was 3%. The difference was that the mass concentration of L-ascorbic acid was adjusted from 0.04% to 0, 0.02%, 0.06% and 0.08% in sequence.

[0052] The survival rate was calculated according to the formula: survival rate (%) = (n / N) × 100%, where N is the number of live bacteria before drying, and n is the number of live bacteria after drying, and the unit is cfu / g.

[0053] The survival rate of the final product is Figure 3As shown in the results, compared with the group without L-ascorbic acid, the survival rate of lactic acid bacteria also increased significantly with the increase of L-ascorbic acid concentration; and reached the highest when the L-ascorbic acid concentration was 0.04%, and then continued to increase the dosage, the survival rate did not increase significantly. Therefore, the optimal concentration of L-ascorbic acid was selected as 0.04%.

[0054] Embodiment 4:

[0055] The operation is the same as in Example 1, except that the mass concentration of trehalose is 4%, the mass concentration of xylo-oligosaccharide is 3%, and the mass concentration of L-ascorbic acid is 0.04%; the difference is that the air inlet temperature and the air outlet temperature of the spray drying are changed, and the air inlet temperature and the air outlet temperature of the spray drying are carried out under the combination conditions shown in Table 1;

[0056] Table 1 Effect of spray drying temperature on the survival rate of lactic acid bacteria

[0057]

[0058] From the effect of spray drying temperature on the survival rate of lactic acid bacteria in Table 1, it can be determined that the optimal air inlet temperature is 80° C. and the air outlet temperature is 45° C. The lactic acid bacteria capsules prepared under the optimal conditions were used as the final product for storage activity determination.

[0059] Storage activity assay:

[0060] The final product of the lactic acid bacteria capsule of Example 4 was sampled on the 15th, 30th and 90th days of storage, respectively, and spread on MRS plate culture medium after dilution, cultured at 37°C for 24 hours, observed and counted. The colony counting results are shown in Table 2, and the unit is cfu / g.

[0061] Table 2 Storage activity of lactic acid bacteria capsules

[0062]

[0063] The storage activity results of the lactic acid bacteria capsules in Table 2 show that the lactic acid bacteria capsules prepared based on the lactic acid bacteria protective agent combined with the spray drying technology of the present invention not only have high activity, but also maintain a relatively high activity after storage; after storage at 4°C for 90 days, the activity can still be maintained at more than 94%; even under the storage condition of 25°C, the activity can be maintained at more than 88% after storage for 90 days, achieving substantial technical effects.

[0064] In summary, the present invention can play a synergistic protective role through the combined use of trehalose, oligoxylose and L-ascorbic acid, reduce the damage to the activity and number of bacteria during the spray drying process, and make the bacteria have higher activity and number of live bacteria; at the same time, prepare the wall material solution, and coat the lactic acid bacteria as the core material in the wall material for secondary protection, thereby protecting them from the influence of the external environment; based on this, the present invention has obtained very significant technical effects compared with comparative example 1; under the action of the protective agent composed of 4% trehalose, 3% oligoxylose and 0.04% L-ascorbic acid by mass concentration, the survival rate of lactic acid bacteria in the prepared lactic acid bacteria capsule is more than 90%.

[0065] In addition, the present invention combines the optimization of spray drying conditions, controls the temperatures of the air inlet and the air outlet, relatively lowers the temperature, optimizes the balance point, minimizes the impact on lactic acid bacteria, and further improves the activity of lactic acid bacteria; the lactic acid bacteria capsules obtained under the combined action of the protective agent and spray drying have an activity of up to 95.13%; and can maintain a very high survival rate during a long storage period, and the survival rate of the lactic acid bacteria capsules can still be maintained at 94.61% at 4° C. and 90 days, achieving significant technical effects; can provide a theoretical research basis for the commercial application of lactic acid bacteria capsules, and has good research value and practical application significance.

[0066] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; therefore, although this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing highly active lactic acid bacteria capsules based on a lactic acid bacteria protective agent combined with spray drying technology, characterized in that: The following steps are involved: (1) Activation of lactic acid bacteria: First, the lactic acid bacteria are cultured and activated in MRS solid medium; then, a single colony of lactic acid bacteria grown in MRS solid medium is selected and inoculated into MRS liquid medium for further culture; after culture, the bacteria are centrifuged to obtain the bacteria, and then washed several times by centrifugation with sterile distilled water, and the bacteria are collected to obtain bacterial mud; finally, the bacteria are dispersed in sterile physiological saline to obtain a lactic acid bacteria suspension, and the concentration of the lactic acid bacteria suspension is not less than 10 10 cells / mL; (2) adding trehalose, xylooligosaccharides and L-ascorbic acid into sterile physiological saline to dissolve to obtain a protective agent solution; then mixing the lactic acid bacteria suspension in step (1) with the protective agent solution to obtain a core material solution; wherein the mass concentration of trehalose in the protective agent solution is 2% to 8%, the mass concentration of xylooligosaccharides is 1% to 5%, and the mass concentration of L-ascorbic acid is 0.04% to 0.08%; (3) heating the sterile physiological saline to 35-45° C., adding fat, edible gum and polyethylene glycol thereto, cooling to room temperature and performing vacuum degassing to obtain a wall material solution; the polyethylene glycol is PEG 4000, the fat includes walnut oil, camellia oil, olive oil, peanut oil or soybean oil; the edible gum includes gelatin, carrageenan, gellan gum or original gum; (4) mixing the core material solution of step (2) and the wall material solution obtained in step (3) to obtain a mixed solution; forming and drying by spray drying to obtain lactic acid bacteria capsules; wherein the air inlet temperature of the spray drying is 75 to 90° C., the air outlet temperature is 45 to 55° C., the vacuum degree is 0.03 to 0.05 MPa, the flow rate is 10 mL / min to 15 mL / min, and the air volume is 2 m 3 / min-4m 3 / min.

2. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: The components of the MRS solid culture medium in step (1) are as follows: based on 1 L, beef extract 10.0 g, yeast extract 5.0 g, peptone 10.0 g, glucose 20.0 g, K2HPO4 2.0 g, sodium acetate 5.0 g, MgSO4·7H2O 0.2 g, MnSO4·4H2O 0.05 g, Tween 80 1.0 g, ammonium citrate tribasic 2.0 g, agar 15.0 g, and distilled water to 1 L; The components of the MRS liquid culture medium are as follows: based on 1 L, beef extract 10.0 g, yeast extract 5.0 g, peptone 10.0 g, glucose 20.0 g, K2HPO4 2.0 g, sodium acetate 5.0 g, MgSO4·7H2O 0.2 g, MnSO4·4H2O 0.05 g, Tween 80 1.0 g, ammonium citrate tribasic 2.0 g, and distilled water to 1 L.

3. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: The temperature of the culture activation in step (1) is 35-40°C, and the time is 48-72h; the conditions for inoculating the single colony into the MRS liquid culture medium for further culture are: 180rpm shaking culture, temperature 35-40°C, and time 48-72h; the amount of the inoculation is: 2-3 loops of single colonies are inoculated in every 50mL of MRS liquid culture medium; the number of washings is 2-3 times, and the centrifugation conditions are 4°C and 6000rpm.

4. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: The lactic acid bacteria in step (1) are Pediococcus acidilactici.

5. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: In step (2), the volume ratio of the lactic acid bacteria suspension and the protective agent solution when mixed is 1:1-2.

6. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: In step (2), the mass concentration of trehalose is 4%, the mass concentration of xylo-oligosaccharide is 3%, and the mass concentration of L-ascorbic acid is 0.04%.

7. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: In step (3), the dosage of fat, edible gum, polyethylene glycol and sterile saline is in the following relationship: 1-3 mL: 1-2 g: 1.5-3 mL: 10-15 mL.

8. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: In step (4), the volume ratio of the core material solution and the material solution when mixed is 1:

1.

9. The method for preparing high-activity lactic acid bacteria capsules based on lactic acid bacteria protective agent combined with spray drying technology according to claim 1, characterized in that: In step (4), the air inlet temperature of the spray drying is 80°C, and the air outlet temperature is 45°C.

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