A coating liquid for enteric bacterial microcapsules and a preparation method and application thereof
By cross-linking modified carboxymethyl cellulose and chitosan quaternary ammonium salt with sodium alginate to form a coating solution, the problem of low survival rate of intestinal probiotics during processing and storage was solved, and the mechanical strength and encapsulation rate of microcapsules were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING HEALSOUL LIFE SCI & TECH CO LTD
- Filing Date
- 2026-03-25
- Publication Date
- 2026-06-09
AI Technical Summary
Intestinal probiotics are easily affected by external environmental interference during processing and storage, and are also susceptible to the acidic environment during digestion, resulting in a low survival rate.
Modified carboxymethyl cellulose and chitosan quaternary ammonium salt were used to modify montmorillonite and crosslink it with sodium alginate to form a coating solution. The mechanical strength and encapsulation efficiency of the microcapsules were improved through transesterification and electrostatic interaction.
It improved the survival rate and encapsulation rate of intestinal probiotics and enhanced the mechanical strength and stability of microcapsules.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of coating liquid technology, specifically a coating liquid for intestinal microcapsules, its preparation method, and its application. Background Technology
[0002] Intestinal bacteria, or probiotics, are live microorganisms that can produce a variety of antibacterial substances, maintain the balance of intestinal flora, improve immunity, and benefit human health. Currently, the most common probiotics are Bifidobacterium and Lactobacillus.
[0003] Intestinal probiotics are widely used in the food industry. However, they are easily affected by the external environment during processing and storage, and are also susceptible to the acidic environment during digestion.
[0004] To address the aforementioned issues and improve the survival rate of intestinal probiotics, this invention provides a coating solution for intestinal microcapsules, its preparation method, and its application. Summary of the Invention
[0005] The purpose of this invention is to provide a coating solution for enterobacterial microcapsules, its preparation method and application, in order to solve the problems raised in the prior art.
[0006] To achieve the above objectives, the present invention provides the following technical solution: Step 1: Add sodium carboxymethyl cellulose to distilled water and stir to obtain a sodium carboxymethyl cellulose solution; add ricinoleate to anhydrous ethanol and mix well to obtain a ricinoleate solution; add the ricinoleate solution to the sodium carboxymethyl cellulose solution, add potassium carbonate aqueous solution, react, remove impurities, and obtain modified carboxymethyl cellulose; Step 2: Add montmorillonite to a sodium chloride aqueous solution, stir, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add modified montmorillonite to distilled water, add chitosan quaternary ammonium salt, react, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite. Step 3: Add sodium alginate and modified carboxymethyl cellulose to sterile water and mix well to obtain coating solution A; Step 4: Add calcium chloride to sterile water, mix well, add chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B; The coating solution includes coating solution A and coating solution B, with a volume ratio of (0.8-1.2):(8-12).
[0007] A more optimized method for preparing ricinoleate is as follows: castor oil and glycerin are mixed evenly, sodium hydroxide is added at a temperature of 220-240℃, and the mixture is reacted for 2-4 hours under a nitrogen atmosphere. Citric acid aqueous solution is added to adjust the pH value, and the mixture is stirred for 15-25 minutes. After removing impurities, the mixture is dried under vacuum to obtain ricinoleate.
[0008] For optimal results, the pH value is adjusted to 6.8-7.2.
[0009] The optimal mass ratio of sodium alginate, modified carboxymethyl cellulose, and sterile water is (1-1.5):(0.2-0.3):(95-105).
[0010] The optimal mass ratio of calcium chloride, sterile water, and chitosan quaternary ammonium salt modified montmorillonite is (1-2):(95-105):(0.4-0.6).
[0011] A more optimized concentration of potassium carbonate aqueous solution is 1.4-1.6%.
[0012] A more optimized method for preparing microcapsules is as follows: Intestinal probiotic strains, specifically Bifidobacterium and Lactobacillus acidophilus, are inoculated, cultured, and activated to the third generation. After centrifugation, the supernatant is discarded to obtain bacterial sludge. Corn starch, resistant dextrin, microcrystalline cellulose, sodium carboxymethyl cellulose, and sterile water are mixed evenly to obtain a mixed solution. The bacterial sludge is added to a glycerol aqueous solution, followed by the mixed solution. The mixture is stirred, granulated, and dried. Coating solution A is added, and the mixture is stirred for 3-5 minutes. Coating solution B is added, and the mixture is solidified for 15-25 minutes. The mixture is then washed and dried to obtain microcapsules.
[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. Preparation of modified carboxymethyl cellulose: Castor oil and glycerol react in the presence of sodium hydroxide to form ricinoleate; carboxymethyl cellulose and ricinoleate undergo transesterification in the presence of potassium carbonate, grafting the hydrophobic long chain of ricinoleic acid from ricinoleate onto the hydrophilic carboxymethyl cellulose, forming amphiphilic modified carboxymethyl cellulose. Its effects are: firstly, the modified carboxymethyl cellulose possesses both hydrophobic long chains of ricinoleic acid and hydrophilic carboxyl groups, exhibiting amphiphilicity, improving the compatibility between components and maintaining interfacial stability; secondly, the modified carboxymethyl cellulose enhances the sodium alginate gel network through multiple mechanisms, improving the mechanical strength of the microcapsules; finally, the hydrophobic long chains of ricinoleic acid in the modified carboxymethyl cellulose increase the encapsulation efficiency of the microcapsules by inhibiting the entry of water molecules.
[0014] 2. Preparation of chitosan quaternary ammonium salt modified montmorillonite: Montmorillonite reacts with sodium chloride, replacing calcium ions in the interlayer of montmorillonite crystals with sodium ions, thereby improving the ion exchange capacity of the modified montmorillonite and increasing its binding strength with chitosan quaternary ammonium salt; thus forming modified montmorillonite. The chitosan quaternary ammonium salt reacts with the modified montmorillonite, combining the positively charged chitosan quaternary ammonium salt with the modified montmorillonite to form chitosan quaternary ammonium salt modified montmorillonite. Its effects are: firstly, the positively charged chitosan quaternary ammonium salt, when combined with the modified montmorillonite, forms a positively charged chitosan quaternary ammonium salt modified montmorillonite, which, through electrostatic interaction, binds to the negatively charged sodium alginate layer, improving the mechanical strength of the microcapsules and increasing their encapsulation efficiency; finally, montmorillonite itself has adsorption properties, which are beneficial to intestinal health.
[0015] 3. Preparation of coating solution: The coating solution includes coating solution A and coating solution B. The bacterial suspension is added to coating solution A, and then coating solution B is added. The calcium ions of calcium chloride in solution B crosslink with sodium alginate to form a sodium alginate layer. Modified carboxymethyl cellulose and modified montmorillonite improve the mechanical strength of the sodium alginate layer through interaction, thereby improving the encapsulation rate of microcapsules. Detailed Implementation
[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] Example 1: A method for preparing a coating solution for intestinal microcapsules; Step 1: Preparation of ricinoleate Take 100g castor oil and 20g glycerol, mix them evenly, add 0.5g sodium hydroxide at 220℃, react for 2h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH value to 6.8, stir for 15min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 1g of ricinoleate was added to 25mL of anhydrous ethanol and mixed evenly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 4h at 280W power and 60℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite 30g of montmorillonite was added to 300mL of 5% sodium chloride aqueous solution. The mixture was stirred for 25min at 55℃, centrifuged, washed, vacuum dried, ground, and sieved to obtain modified montmorillonite. Modified montmorillonite was then added to 300mL of distilled water, along with 2.5g of chitosan quaternary ammonium salt. The mixture was reacted for 4h at 60℃, centrifuged, washed, and dried to obtain chitosan quaternary ammonium salt modified montmorillonite. Step 4: Prepare the coating solution S1: Add 0.2g sodium alginate and 0.04g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0018] Example 2: A method for preparing a coating solution for intestinal microcapsules; Step 1: Preparation of ricinoleate Take 100g castor oil and 25g glycerol, mix them evenly, add 1g sodium hydroxide at 230℃, react for 3h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.0, stir for 20min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 2g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5h at 300W and 65℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite Add 30g of montmorillonite to 300mL of 5% sodium chloride aqueous solution, stir for 30min at 60℃, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add 3g of chitosan quaternary ammonium salt to 300mL of distilled water, react for 4h at 60℃, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite; Step 4: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.05g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0019] Example 3: A method for preparing a coating solution for intestinal bacteria microcapsules; Step 1: Preparation of ricinoleate Take 100g castor oil and 30g glycerol, mix them evenly, add 1.5g sodium hydroxide at 240℃, react for 4h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.2, stir for 25min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 3g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 6h at 320W power and 70℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite 30g of montmorillonite was added to 300mL of 5% sodium chloride aqueous solution. The mixture was stirred for 35min at 65℃, centrifuged, washed, vacuum dried, ground, and sieved to obtain modified montmorillonite. Modified montmorillonite was then added to 300mL of distilled water, along with 3.5g of chitosan quaternary ammonium salt. The mixture was reacted for 4h at 60℃, centrifuged, washed, and dried to obtain chitosan quaternary ammonium salt modified montmorillonite. Step 4: Prepare the coating solution S1: Add 0.3g sodium alginate and 0.06g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 2g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0020] Comparative Example 1: Castor oil ester was not added; otherwise, refer to Example 2. Step 1: Preparation of modified carboxymethyl cellulose 1 g of sodium carboxymethyl cellulose was added to 25 mL of distilled water and stirred for 1 h to obtain a sodium carboxymethyl cellulose solution. 25 mL of anhydrous ethanol was added to the sodium carboxymethyl cellulose solution, and 5 mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5 h at a power of 300 W and a temperature of 65 °C to remove impurities and obtain modified carboxymethyl cellulose. Step 2: Preparation of chitosan quaternary ammonium salt modified montmorillonite Add 30g of montmorillonite to 300mL of 5% sodium chloride aqueous solution, stir for 30min at 60℃, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add 3g of chitosan quaternary ammonium salt to 300mL of distilled water, react for 4h at 60℃, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite; Step 3: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.05g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0021] Comparative Example 2: No modified carboxymethyl cellulose was added; all other aspects are the same as in Example 2. Step 1: Preparation of chitosan quaternary ammonium salt modified montmorillonite Add 30g of montmorillonite to 300mL of 5% sodium chloride aqueous solution, stir for 30min at 60℃, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add 3g of chitosan quaternary ammonium salt to 300mL of distilled water, react for 4h at 60℃, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite; Step 2: Preparation of coating solution S1: Add 0.25g of sodium alginate to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0022] Comparative Example 3: The amount of modified carboxymethyl cellulose added was increased, and the rest was the same as in Example 2; Step 1: Preparation of ricinoleate Take 100g castor oil and 25g glycerol, mix them evenly, add 1g sodium hydroxide at 230℃, react for 3h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.0, stir for 20min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 2g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5h at 300W and 65℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite Add 30g of montmorillonite to 300mL of 5% sodium chloride aqueous solution, stir for 30min at 60℃, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add 3g of chitosan quaternary ammonium salt to 300mL of distilled water, react for 4h at 60℃, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite; Step 4: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.1g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0023] Comparative Example 4: No sodium chloride was added; otherwise, refer to Example 2. Step 1: Preparation of ricinoleate Take 100g castor oil and 25g glycerol, mix them evenly, add 1g sodium hydroxide at 230℃, react for 3h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.0, stir for 20min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 2g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5h at 300W and 65℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite Add 30g of montmorillonite to 300mL of distilled water, stir for 30min at 60℃, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add 3g of chitosan quaternary ammonium salt to 300mL of distilled water, react for 4h at 60℃, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite; Step 4: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.05g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0024] Comparative Example 5: No chitosan quaternary ammonium salt was added; all other aspects are the same as in Example 2. Step 1: Preparation of ricinoleate Take 100g castor oil and 25g glycerol, mix them evenly, add 1g sodium hydroxide at 230℃, react for 3h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.0, stir for 20min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 2g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5h at 300W and 65℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite 30g of montmorillonite was added to 300mL of 5% sodium chloride aqueous solution. The mixture was stirred for 30min at 60℃, centrifuged, washed, vacuum dried, ground, and sieved to obtain modified montmorillonite. Modified montmorillonite was then added to 300mL of distilled water and reacted for 4h at 60℃. The mixture was then centrifuged, washed, and dried to obtain chitosan quaternary ammonium salt modified montmorillonite. Step 4: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.05g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 0.5g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0025] Comparative Example 6: Montmorillonite without the addition of chitosan quaternary ammonium salt, otherwise refer to Example 2; Step 1: Preparation of ricinoleate Take 100g castor oil and 25g glycerol, mix them evenly, add 1g sodium hydroxide at 230℃, react for 3h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.0, stir for 20min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 2g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5h at 300W and 65℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.05g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, and sonicate to obtain coating solution B.
[0026] Comparative Example 7: Increase the amount of chitosan quaternary ammonium salt modified montmorillonite, and refer to Example 2 for the rest; Step 1: Preparation of ricinoleate Take 100g castor oil and 25g glycerol, mix them evenly, add 1g sodium hydroxide at 230℃, react for 3h under nitrogen atmosphere, add 10% citric acid aqueous solution to adjust the pH to 7.0, stir for 20min, remove impurities, and vacuum dry at 60℃ to obtain castor oil ester. Step 2: Preparation of modified carboxymethyl cellulose 1g of sodium carboxymethyl cellulose was added to 25mL of distilled water and stirred for 1h to obtain a sodium carboxymethyl cellulose solution. 2g of ricinoleate was added to 25mL of anhydrous ethanol and mixed thoroughly to obtain a ricinoleate solution. The ricinoleate solution was added to the sodium carboxymethyl cellulose solution, and 5mL of 1.5% potassium carbonate aqueous solution was added. The mixture was reacted for 5h at 300W and 65℃ to remove impurities and obtain modified carboxymethyl cellulose. Step 3: Preparation of chitosan quaternary ammonium salt modified montmorillonite Add 30g of montmorillonite to 300mL of 5% sodium chloride aqueous solution, stir for 30min at 60℃, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add 3g of chitosan quaternary ammonium salt to 300mL of distilled water, react for 4h at 60℃, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite; Step 4: Prepare the coating solution S1: Add 0.25g sodium alginate and 0.05g modified carboxymethyl cellulose to 20mL of sterile water and mix well to obtain coating solution A; S2: Add 1.5g of calcium chloride to 100mL of sterile water, mix well, add 1.0g of chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B.
[0027] experiment: The coating solutions prepared in Examples 1-3 and Comparative Examples 1-7 were tested. Intestinal probiotic strains, namely Bifidobacterium and Lactobacillus acidophilus, were inoculated, cultured, and activated to the third generation. The cultures were centrifuged at 4000 rpm for 15 minutes, and the supernatant was discarded to obtain bacterial sludge. 50 wt% corn starch, 10 wt% resistant dextrin, 5 wt% microcrystalline cellulose, 2 wt% sodium carboxymethyl cellulose, and 33 wt% sterile water were mixed thoroughly to obtain a mixed solution. The bacterial sludge was added to a 10% glycerol aqueous solution, followed by the mixed solution. The mixture was stirred, granulated, and dried. Coating solution A was added, and the mixture was stirred for 3 minutes. Coating solution B was added, and the mixture was solidified for 15 minutes. The volume ratio of coating solution A to coating solution B was 1:10. The mixture was washed and dried to obtain microcapsules. Add 1g of microcapsules to 9mL of phosphate buffer, and shake for 1h at 37℃ and 200rpm. Calculate the encapsulation efficiency using the following formula: Encapsulation efficiency = Total viable bacteria count in the microcapsules after shaking / Initial total viable bacteria count; The total number of viable bacteria in the microcapsules after shaking = the total mass of the microcapsules × the number of viable bacteria per 1g of microcapsules after shaking; the initial total number of viable bacteria = the total volume of the bacterial suspension × the concentration; The above experiments were completed, and the results are shown in Table 1 below: Table 1
[0028] Conclusion: Based on the analysis of the above experimental data, the microcapsules prepared in Examples 1-3 of this invention have a high encapsulation rate, indicating a high survival rate of intestinal probiotics; while the microcapsules prepared in Comparative Examples 1-7 have a low encapsulation rate, indicating a low survival rate of intestinal probiotics.
[0029] Comparative analysis of Comparative Example 1 (without ricinoleate) and Example 2 shows that carboxymethyl cellulose and ricinoleate undergo transesterification under the action of potassium carbonate, grafting the hydrophobic long chain of ricinoleic acid onto the hydrophilic carboxymethyl cellulose to form amphiphilic modified carboxymethyl cellulose. On the one hand, the modified carboxymethyl cellulose has hydrophobic long chains of ricinoleic acid and hydrophilic carboxyl groups, exhibiting amphiphilicity, which improves the compatibility between components and maintains interfacial stability. On the other hand, the hydrophobic long chains of ricinoleic acid in the modified carboxymethyl cellulose increase the encapsulation efficiency of microcapsules by inhibiting water molecules from entering the microcapsules.
[0030] Comparative analysis of Comparative Example 2 (without modified carboxymethyl cellulose) and Example 2 reveals that the modified carboxymethyl cellulose has the following effects: First, it possesses hydrophobic ricinoleic acid chains and hydrophilic carboxyl groups, exhibiting amphiphilicity, which improves the compatibility between components and maintains interfacial stability. Second, it enhances the sodium alginate gel network through multiple mechanisms, thereby increasing the mechanical strength of the microcapsules. Finally, the hydrophobic ricinoleic acid chains of the modified carboxymethyl cellulose increase the encapsulation efficiency of the microcapsules by inhibiting the entry of water molecules into them.
[0031] Comparative analysis of Comparative Example 3 and Example 2, which increased the amount of modified carboxymethyl cellulose added, showed that under a specific ratio, the modified carboxymethyl cellulose was uniformly dispersed in coating solution A and functioned stably.
[0032] Comparative analysis of Comparative Example 4 (without sodium chloride) and Example 2 shows that montmorillonite reacts with sodium chloride, replacing calcium ions in the interlayer of montmorillonite crystals with sodium ions, thereby improving the ion exchange capacity of the modified montmorillonite, increasing its bonding strength with chitosan quaternary ammonium salt, further improving the bonding strength between the chitosan quaternary ammonium salt-modified montmorillonite and the sodium alginate layer, improving the mechanical strength of the microcapsules, and increasing the encapsulation rate of the microcapsules.
[0033] Comparative analysis of Comparative Example 5 (without chitosan quaternary ammonium salt) and Example 2 shows that chitosan quaternary ammonium salt is positively charged. When it combines with modified montmorillonite, it forms a chitosan quaternary ammonium salt-modified montmorillonite layer that is positively charged. Through electrostatic interaction, it combines with the negatively charged sodium alginate layer, thereby improving the mechanical strength of the microcapsules and increasing the encapsulation rate of the microcapsules.
[0034] Comparative analysis of Comparative Example 6 (without chitosan quaternary ammonium salt modified montmorillonite) and Example 2 reveals that the role of chitosan quaternary ammonium salt modified montmorillonite is as follows: First, chitosan quaternary ammonium salt is positively charged, and when it combines with modified montmorillonite, the resulting positively charged chitosan quaternary ammonium salt modified montmorillonite combines with the negatively charged sodium alginate layer through electrostatic interaction, thereby improving the mechanical strength of the microcapsules and increasing their encapsulation efficiency. Finally, montmorillonite itself has adsorption properties, which are beneficial to intestinal health.
[0035] Comparative analysis of Comparative Example 7 and Example 2, which increased the amount of chitosan quaternary ammonium salt modified montmorillonite, showed that under a specific ratio, the chitosan quaternary ammonium salt modified montmorillonite was uniformly dispersed in coating solution B and functioned stably.
[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
Claims
1. A method for preparing a coating solution for intestinal microcapsules, characterized in that: Includes the following steps: Step 1: Add sodium carboxymethyl cellulose to distilled water and stir to obtain a sodium carboxymethyl cellulose solution; Castor oil ester was added to anhydrous ethanol and mixed thoroughly to obtain a castor oil ester solution. The castor oil ester solution was then added to a sodium carboxymethyl cellulose solution, followed by the addition of potassium carbonate aqueous solution. The mixture was reacted and impurities were removed to obtain modified carboxymethyl cellulose. Step 2: Add montmorillonite to a sodium chloride aqueous solution, stir, centrifuge, wash, vacuum dry, grind, and sieve to obtain modified montmorillonite; add modified montmorillonite to distilled water, add chitosan quaternary ammonium salt, react, centrifuge, wash, and dry to obtain chitosan quaternary ammonium salt modified montmorillonite. Step 3: Add sodium alginate and modified carboxymethyl cellulose to sterile water and mix well to obtain coating solution A; Step 4: Add calcium chloride to sterile water, mix well, add chitosan quaternary ammonium salt modified montmorillonite, and sonicate to obtain coating solution B; The coating solution includes coating solution A and coating solution B, with a volume ratio of (0.8-1.2):(8-12).
2. The method for preparing a coating solution for intestinal microcapsules according to claim 1, characterized in that: The method for preparing the castor oil ester is as follows: castor oil and glycerin are mixed evenly, sodium hydroxide is added at a temperature of 220-240℃, and the reaction is carried out for 2-4 hours under a nitrogen atmosphere. Citric acid aqueous solution is added to adjust the pH value, and the mixture is stirred for 15-25 minutes. Impurities are removed, and the mixture is dried under vacuum to obtain castor oil ester.
3. The method for preparing a coating solution for intestinal microcapsules according to claim 2, characterized in that: The pH value is adjusted to 6.8-7.
2.
4. The method for preparing a coating solution for intestinal microcapsules according to claim 1, characterized in that: The mass ratio of sodium alginate, modified carboxymethyl cellulose, and sterile water is (1-1.5):(0.2-0.3):(95-105).
5. The method for preparing a coating solution for intestinal microcapsules according to claim 1, characterized in that: The mass ratio of calcium chloride, sterile water, and chitosan quaternary ammonium salt modified montmorillonite is (1-2):(95-105):(0.4-0.6).
6. The method for preparing a coating solution for intestinal microcapsules according to claim 1, characterized in that: The concentration of the potassium carbonate aqueous solution is 1.4-1.6%.
7. A coating solution for intestinal bacteria microcapsules prepared by the method for preparing a coating solution for intestinal bacteria microcapsules according to any one of claims 1-6.
8. The application of the coating solution for enterobacterial microcapsules according to claim 7 on microcapsules.
9. A microcapsule according to claim 8, characterized in that: The preparation method of the microcapsules is as follows: Take intestinal probiotic strains, namely Bifidobacterium and Lactobacillus acidophilus, inoculate, culture, activate to the third generation, centrifuge, discard the supernatant to obtain bacterial sludge; take corn starch, resistant dextrin, microcrystalline cellulose, sodium carboxymethyl cellulose, and sterile water, mix evenly to obtain a mixed solution; take the bacterial sludge and add it to an aqueous glycerol solution, add the mixed solution, stir, granulate, dry, add coating solution A, stir for 3-5 minutes, add coating solution B, solidify for 15-25 minutes, wash, dry, and obtain microcapsules.