Ultrasound-assisted pH-responsive malquist anthocyanin microcapsules preparation method

Abstract

This invention relates to the field of microcapsule preparation, specifically to an ultrasound-assisted pH-responsive method for preparing malkiberry anthocyanin microcapsules, comprising the following preparation steps: S1: core material preparation; S2: wall material preparation; S3: oil phase preparation; S4: aqueous phase preparation; S5: ultrasonic emulsification; S6: solidification; S7: separation and washing; S8: drying and temperature control. This invention selects a specific combination of wall materials that are stable in gastric acid and can responsively dissociate or swell under intestinal pH conditions. Using ultrasound-assisted preparation technology, malkiberry anthocyanin microcapsules are prepared through cavitation and mechanical effects. Furthermore, the temperature is controlled below 30°C during the preparation process. The resulting microcapsules achieve an encapsulation rate of 68%–75%, effectively protecting the malkiberry anthocyanins from the gastric acid environment and enabling pH-responsive release in the intestine. This significantly improves the stability and oral bioavailability of malkiberry anthocyanins, demonstrating broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of microcapsule preparation, specifically to an ultrasound-assisted method for preparing pH-responsive malquist anthocyanin microcapsules. Background Technology

[0002] Maquiberry anthocyanins are a class of water-soluble natural pigments with various biological activities, such as anti-oxidation, anti-inflammation, and anti-tumor effects. They have important application value in the fields of food, health products, and pharmaceuticals. However, maquiberry anthocyanins are only stable in strongly acidic environments with a pH < 3.0 and are easily degraded in neutral or alkaline environments, resulting in poor stability. At the same time, after oral administration, maquiberry anthocyanins are easily destroyed in the acidic environment of the stomach and are difficult to reach the intestines for effective absorption, resulting in low oral bioavailability and severely limiting their practical application.

[0003] To address the aforementioned issues, current research has employed microencapsulation technology to protect malkiberry anthocyanins. Microencapsulation technology involves encapsulating the core material within a wall material to form tiny capsules, which can protect the core material from external environmental influences and control the release rate and release site of the core material.

[0004] In existing technologies, the wall materials commonly used are mostly single materials or simple mixtures, which have poor pH response performance and make it difficult to achieve precise release of the core material in the intestine. Moreover, the preparation methods mostly adopt traditional emulsification and cross-linking methods, which have problems such as uneven emulsification, wide microcapsule particle size distribution, and low encapsulation efficiency. Ultrasonic-assisted preparation technology utilizes the cavitation and mechanical effects of ultrasound to effectively improve the emulsification effect, making the emulsion droplets more uniform and fine, and improving the encapsulation efficiency and stability of microcapsules. Therefore, an ultrasonic-assisted pH-responsive malquist anthocyanin microcapsule preparation method is proposed to address the above problems. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies and solve at least one of the technical problems mentioned in the background art, this invention proposes an ultrasound-assisted pH-responsive method for preparing maquilli anthocyanin microcapsules.

[0006] The technical solution adopted by this invention to solve its technical problem is: an ultrasound-assisted pH-responsive malquist anthocyanin microcapsule preparation method, comprising the following steps: S1: Core material preparation: Dissolve the anthocyanin extract of maquillia in 0.1M citrate-sodium citrate buffer solution with pH < 3.0, at a concentration of 20-50 mg / mL, and store in the dark. S2: Wall material preparation: Select the wall material combination as sodium alginate-chitosan, sodium alginate-carboxymethyl chitosan or sodium alginate-high fat pectin, and prepare solutions of each wall material component respectively; S3: Oil phase preparation: Add the emulsifier to the vegetable oil to prepare a 1%-3% (w / v) solution, then add 0.5% of the oil-soluble calcium source, and stir or sonicate to completely dissolve it; if calcium carbonate is used as the calcium source, calcium carbonate and glucono-delta-lactone need to be dispersed in the oil phase at a mass ratio of 1:2. S4: Aqueous phase preparation: According to the selected wall material combination, the core material solution and the corresponding wall material solution are mixed in a specific ratio and stirred evenly to obtain the aqueous phase; S5: Ultrasonic emulsification: Slowly pour the aqueous phase into the oil phase, stir, and process with pulsed ultrasonic-assisted technology. Set the power to 100-250w, pulse for 3 seconds, pause for 5 seconds, and the total ultrasonic treatment time is 5-8 minutes to obtain uniformly dispersed W / O primary emulsion droplets. S6: Curing: Stir the W / O emulsion, slowly add 0.5%–1% acetic acid (by volume of the oil phase), and stir for 20–30 minutes. The emulsion viscosity will increase significantly, forming “pre-cured” microspheres or solid microcapsules. The addition of acetic acid can adjust the pH value of the system, promote the interaction and cross-linking reaction between the wall materials, and achieve the pre-curing of the microcapsules. Then, depending on the selected wall material combination, select the appropriate curing method, and continue stirring for a certain period of time or let it stand. S7: Separation and washing: Stop stirring and separate the solidified microcapsules from the reaction solution by centrifugation or filtration. Discard the supernatant and wash 2-3 times with 0.1M citrate-sodium citrate buffer solution with pH < 3.0, and then wash once with deionized water to remove unreacted wall material, salt or other impurities remaining on the surface. S8: Drying and Temperature Control: The washed microcapsules are made into powder by freeze drying or spray drying, with the temperature controlled at <30°C throughout the process to reduce the risk of degradation of maquilli anthocyanins and changes in wall material properties caused by high temperatures.

[0007] As a preferred embodiment, the specific composition of the wall material combination in step S2 is as follows: Sodium alginate-chitosan combination: The mass ratio of sodium alginate to chitosan is 1:0.8-1:1.5; Sodium alginate-high ester pectin combination: The mass ratio of sodium alginate to high ester pectin is 1:2-2:1.

[0008] Preferably, the preparation parameters for each wall material component solution in step S2 are as follows: Sodium alginate solution: Dissolve in deionized water to prepare a 1.5%–2.5% (w / v) solution, adjust the pH to 4.0–5.0, and cool to room temperature; Chitosan solution: Dissolve in 0.5%–1.5% dilute acetic acid solution to prepare a 1.0% (w / v) solution, and adjust the pH value to 4.0–5.0; Carboxymethyl chitosan solution: Dissolve in deionized water to prepare a 0.5%–2.0% (w / v) solution; Sodium alginate-high ester pectin mixed solution: Dissolve in water to prepare a 1.5%-3.0% (w / v) solution, and adjust the pH to 4.0-5.0.

[0009] Preferably, the volume ratio of the aqueous phase to the oil phase in step S4 varies depending on the wall material combination: Sodium alginate-chitosan combination: 1:4-1:10; Sodium alginate-carboxymethyl chitosan combination: 1:3-1:6; Sodium alginate-high ester pectin combination: 1:4-1:10.

[0010] Preferably, the solid mass ratio of the core material to the wall material in step S4 is: Sodium alginate-chitosan combination: 1:10-1:15; Sodium alginate-high ester pectin combination: 1:10-1:20; Sodium alginate-carboxymethyl chitosan combination: The volume ratio of core material solution, sodium alginate solution, and carboxymethyl chitosan solution is 0.5:1:1.

[0011] Preferably, the emulsifier in step S3 is selected from nonionic emulsifiers of the Span series and Tween series, or natural emulsifiers such as lecithin and sucrose fatty acid esters, with Span 80 being preferred due to its strong emulsification stability and compatibility with oil-phase systems; the vegetable oil is selected from edible-grade vegetable oils such as corn oil, soybean oil, olive oil, and sunflower seed oil, with corn oil being preferred due to its moderate viscosity, mild flavor, and lack of impact on the activity of maquilli anthocyanins; the oil-soluble calcium source is selected from long-chain fatty acid calcium salts such as calcium caprylate, calcium stearate, and calcium palmitate, with calcium caprylate being preferred due to its high solubility in vegetable oils and its ability to quickly participate in subsequent solidification reactions to form stable microcapsule structures.

[0012] As a preferred option, the curing method for different wall material combinations in step S6 is as follows: Sodium alginate-chitosan combination: Slowly add the reaction solution to the chitosan solution while stirring, and continue stirring at room temperature for 30-45 minutes; Sodium alginate-carboxymethyl chitosan combination: After the reaction solution is allowed to stand, the microsphere suspension is collected by filtration or centrifugation; Sodium alginate-high ester pectin combination: After the reaction solution is allowed to stand, the microsphere suspension is collected by filtration or centrifugation.

[0013] Preferably, the pH-responsive maquilli anthocyanin microcapsules prepared by the method are preferred.

[0014] Preferably, the pH-responsive maquilli anthocyanin microcapsules are used in the food, health product, or pharmaceutical fields.

[0015] The advantages of this invention are: 1. This invention selects different wall material combinations such as sodium alginate-chitosan, sodium alginate-carboxymethyl chitosan, or sodium alginate-high ester pectin, which have good stability in the gastric acid environment and can responsively dissociate or swell under intestinal pH conditions, thereby achieving targeted release of masquiberry anthocyanins in the intestine, effectively protecting masquiberry anthocyanins from gastric acid destruction and improving their oral bioavailability.

[0016] 2. This invention employs ultrasound-assisted preparation technology, utilizing the cavitation and mechanical effects of ultrasound to make the aqueous phase more uniformly dispersed in the oil phase, resulting in smaller and narrower emulsion droplet sizes, which significantly improves the encapsulation efficiency of microcapsules, reaching 68%–75%.

[0017] 3. The preparation method of the present invention is simple to operate and has mild conditions, with the temperature controlled at <30°C throughout the process, which avoids the influence of high temperature on the activity of malkiberry anthocyanins. In addition, the raw materials used are safe and non-toxic, meeting the application requirements of food, health products and pharmaceuticals.

[0018] 4. The pH-responsive malquist anthocyanin microcapsules prepared by this invention have good stability, are easy to store and transport, and have broad application prospects in the fields of food, health products and pharmaceuticals. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0022] The following is in conjunction with the appendix Figure 1 This application will be described in further detail. Example 1 (Preparation of pH-responsive maquilli anthocyanin microcapsules using sodium alginate-chitosan wall material combination) This application discloses a method for preparing ultrasound-assisted pH-responsive maquilli anthocyanin microcapsules. (Refer to...) Figure 1An ultrasound-assisted method for preparing pH-responsive maquilli anthocyanin microcapsules includes the following steps: S1: Core material preparation: Dissolve the anthocyanin extract of maquillia in 0.1M citrate-sodium citrate buffer solution with pH < 3.0 to obtain a core material solution with a concentration of 20-50 mg / mL, and store it under light-protected conditions for later use; S2: Wall material preparation: Weigh an appropriate amount of sodium alginate, dissolve it in deionized water to prepare a 2.0% (w / v) solution, stir and sonicate until completely dissolved, adjust the pH of the solution to 4.5, and cool to room temperature; Weigh an appropriate amount of chitosan, dissolve it in a 1.0% dilute acetic acid solution to prepare a 1.0% (w / v) solution, stir and sonicate until completely dissolved, and adjust the pH of the solution to 4.5; S3: Oil phase preparation: Add Span80 to corn oil to prepare a 2% (w / v) solution, then add an oil-soluble calcium source and sonicate thoroughly to dissolve it completely. S4: Aqueous phase preparation: Mix the core material solution and sodium alginate solution at a solid mass ratio of 1:12, stir evenly to obtain the aqueous phase; S5: Ultrasonic emulsification: The aqueous phase is slowly poured into the oil phase at a volume ratio of 1:7. After stirring, pulsed ultrasonic-assisted technology is used for treatment. The power is set to 180W, with a pulse working time of 3 seconds and an interval of 5 seconds. The total ultrasonic treatment time is 6 minutes to obtain uniformly dispersed W / O primary emulsion droplets. S6: Curing: Stir the W / O emulsion, slowly add 0.8% acetic acid by volume of the oil phase, stir for 25 minutes, the emulsion viscosity increases significantly, forming "pre-cured" microspheres, then slowly add the reaction solution to the chitosan solution while stirring, and continue stirring at room temperature for 40 minutes; S7: Separation and washing: Centrifuge to separate the microcapsules, discard the supernatant, wash 3 times with 0.1M citrate-sodium citrate buffer (pH < 3.0), and then wash once with deionized water; S8: Drying and temperature control: The microcapsules are freeze-dried into powder, and the temperature is controlled at <30°C throughout the preparation process.

[0023] Encapsulation efficiency measured: 75%.

[0024] Example 2 (Preparation of pH-responsive maquilli anthocyanin microcapsules using sodium alginate-carboxymethyl chitosan wall material combination) An ultrasound-assisted method for preparing pH-responsive malquist anthocyanin microcapsules includes the following steps: S1: Core material preparation: Dissolve the anthocyanin extract of maquillia in 0.1M citrate-sodium citrate buffer solution with pH < 3.0 to a concentration of 25 mg / mL, and prepare in the dark; S2: Wall material preparation: Weigh an appropriate amount of sodium alginate, dissolve it in deionized water to prepare a 1.8% (w / v) solution, stir and sonicate until completely dissolved, adjust the pH of the solution to 4.2, and cool to room temperature; dissolve carboxymethyl chitosan in deionized water to prepare a 1.2% (w / v) solution, and stir until completely dissolved; S3: Oil phase preparation: Add Span80 to corn oil to prepare a 1.5% (w / v) solution, then add an oil-soluble calcium source and stir thoroughly to dissolve it completely; S4: Aqueous phase preparation: Before use, mix the core material solution, sodium alginate solution, and carboxymethyl chitosan solution at a volume ratio of 0.5:1:1, stir evenly, and form a mixed wall material-core material solution as the aqueous phase; S5: Ultrasonic emulsification: The aqueous phase is slowly poured into the oil phase at a volume ratio of 1:4. After stirring, pulsed ultrasonic-assisted technology is used for treatment. The power is set to 150W, with a pulse working time of 3 seconds and an interval of 5 seconds. The total ultrasonic treatment time is 5.5 minutes, resulting in a uniformly dispersed W / O primary emulsion droplet. S6: Curing: Stir the W / O emulsion, slowly add 0.6% acetic acid by volume of the oil phase, stir for 22 min to form microspheres, then let the reaction solution stand, and centrifuge to collect the microsphere suspension; S7: Separation and washing: Centrifuge to separate the microcapsules, discard the supernatant, wash 3 times with 0.1M citrate-sodium citrate buffer (pH < 3.0), and then wash once with deionized water; S8: Drying and temperature control: Centrifuge to separate the microcapsules, discard the supernatant, wash twice with 0.1M citrate-sodium citrate buffer solution with pH < 3.0, and then wash once with deionized water. The temperature is controlled at < 30°C throughout the preparation process.

[0025] Encapsulation efficiency measured: 72% Example 3 (Preparation of pH-responsive maquilli anthocyanin microcapsules using a combination of sodium alginate and high-ester pectin wall material) An ultrasound-assisted method for preparing pH-responsive malquist anthocyanin microcapsules includes the following steps: S1: Core material preparation: Dissolve the anthocyanin extract of maquillia in 0.1M citrate-sodium citrate buffer solution with pH < 3.0 to a concentration of 40 mg / mL, and store in the dark. S2: Wall material preparation: Weigh an appropriate amount of sodium alginate and high ester pectin, dissolve them in water at a mass ratio of 1:1 to prepare a 2.5% (w / v) solution, stir and use ultrasonic assistance until completely dissolved, and adjust the pH of the solution to 4.8. S3: Oil phase preparation: Add Span80 to corn oil to prepare a 2.5% (w / v) solution, then add an oil-soluble calcium source and sonicate thoroughly to dissolve it completely. S4: Aqueous phase preparation: Add the core material solution to the sodium alginate-high ester pectin mixed solution, mix at a solid mass ratio of 1:15, stir evenly to obtain the aqueous phase; S5: Ultrasonic emulsification: The aqueous phase is slowly poured into the oil phase at a volume ratio of 1:8. After stirring, pulsed ultrasonic-assisted technology is used for treatment. The power is set to 220W, with a pulse working time of 3 seconds and an interval of 5 seconds. The total ultrasonic treatment time is 7 minutes to obtain a uniformly dispersed W / O primary emulsion. S6: Curing: Stir the W / O emulsion, slowly add 0.9% acetic acid by volume of the oil phase, stir for 28 min to form solid microcapsules, then let the reaction solution stand, filter and collect the microsphere suspension; S7: Separation and washing: Centrifuge to separate the microcapsules, discard the supernatant, wash 3 times with 0.1M citrate-sodium citrate buffer (pH < 3.0), and then wash once with deionized water; S8: Drying and temperature control: The microcapsules are freeze-dried into powder, and the temperature is controlled at <30°C throughout the preparation process.

[0026] Encapsulation efficiency measured: 68% The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing ultrasound-assisted pH-responsive marijuana anthocyanin microcapsules, characterized in that: Includes the following steps: S1: Core material preparation: Dissolve the anthocyanin extract of maquillia in 0.1M citrate-sodium citrate buffer solution with pH < 3.0 to obtain a core material solution with a concentration of 20-50 mg / mL, and store it under light-protected conditions for later use; S2: Wall material preparation: Select the wall material combination as sodium alginate-chitosan, sodium alginate-carboxymethyl chitosan or sodium alginate-high fat pectin, and prepare solutions of each wall material component separately; S3: Oil phase preparation: Add the emulsifier to the vegetable oil to prepare a 1%-3% (w / v) solution, then add 0.5% of the oil-soluble calcium source, and stir or sonicate to completely dissolve it; if calcium carbonate is used as the calcium source, calcium carbonate and glucono-delta-lactone need to be dispersed in the oil phase at a mass ratio of 1:

2. S4: Aqueous phase preparation: According to the selected wall material combination, the core material solution and the corresponding wall material solution are mixed in a specific ratio and stirred evenly to obtain the aqueous phase; S5: Ultrasonic emulsification: Slowly pour the aqueous phase into the oil phase, stir, and process with pulsed ultrasonic-assisted technology. Set the power to 100-250w, pulse for 3 seconds, pause for 5 seconds, and the total ultrasonic treatment time is 5-8 minutes to obtain uniformly dispersed W / O primary emulsion droplets. S6: Curing: Stir the W / O emulsion, slowly add 0.5%-1% acetic acid by volume of the oil phase, stir for 20-30 minutes to form pre-cured microspheres or solid microcapsules, and then select the appropriate curing method according to the selected wall material combination, continue stirring for a certain time or let stand. S7: Separation and washing: Separate the microcapsules by centrifugation or filtration, wash them 2-3 times with 0.1M citrate-sodium citrate buffer solution with pH < 3.0, and then wash them once with deionized water. S8: Drying and temperature control: The microcapsules are made into powder by freeze drying or spray drying, and the temperature is controlled at <30°C throughout the preparation process.

2. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 1, characterized in that: The specific configuration of the wall material combination in step S2 is as follows: Sodium alginate-chitosan combination: The mass ratio of sodium alginate to chitosan is 1:0.8-1:1.5; Sodium alginate-high ester pectin combination: The mass ratio of sodium alginate to high ester pectin is 1:2-2:

1.

3. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 1, characterized in that: The preparation parameters for each wall material component solution in step S2 are as follows: Sodium alginate solution: Dissolve in deionized water to prepare a 1.5%–2.5% (w / v) solution, adjust the pH to 4.0–5.0, and cool to room temperature; Chitosan solution: Dissolve in 0.5%–1.5% dilute acetic acid solution to prepare a 1.0% (w / v) solution, and adjust the pH value to 4.0–5.0; Carboxymethyl chitosan solution: Dissolve in deionized water to prepare a 0.5%–2.0% (w / v) solution; Sodium alginate-high ester pectin mixed solution: Dissolve in water to prepare a 1.5%-3.0% (w / v) solution, and adjust the pH to 4.0-5.

0.

4. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 1, characterized in that: In step S4, the volume ratio of the aqueous phase to the oil phase varies depending on the wall material combination: Sodium alginate-chitosan combination: 1:4-1:10; Sodium alginate-carboxymethyl chitosan combination: 1:3-1:6; Sodium alginate-high ester pectin combination: 1:4-1:

10.

5. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 1, characterized in that: In step S4, the solid mass ratio of the core material to the wall material is: Sodium alginate-chitosan combination: 1:10-1:15; Sodium alginate-high ester pectin combination: 1:10-1:20; Sodium alginate-carboxymethyl chitosan combination: The volume ratio of core material solution, sodium alginate solution, and carboxymethyl chitosan solution is 0.5:1:

1.

6. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 1, characterized in that: The emulsifier in step S3 is selected from nonionic emulsifiers of the Span series and Tween series, or natural emulsifiers such as lecithin and sucrose fatty acid esters, preferably Span 80; the vegetable oil is selected from edible-grade vegetable oils such as corn oil, soybean oil, olive oil, and sunflower seed oil, preferably corn oil; the oil-soluble calcium source is selected from long-chain fatty acid calcium salts such as calcium caprylate, calcium stearate, and calcium palmitate, preferably calcium caprylate.

7. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 1, characterized in that: The curing methods for different wall material combinations in step S6 are as follows: Sodium alginate-chitosan combination: Slowly add the reaction solution to the chitosan solution while stirring, and continue stirring at room temperature for 30-45 minutes; Sodium alginate-carboxymethyl chitosan combination: After the reaction solution is allowed to stand, the microsphere suspension is collected by filtration or centrifugation; Sodium alginate-high ester pectin combination: After the reaction solution is allowed to stand, the microsphere suspension is collected by filtration or centrifugation.

8. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to any one of claims 1-7, characterized in that: The method described above prepares pH-responsive maquilli anthocyanin microcapsules.

9. The method for preparing ultrasound-assisted pH-responsive malquist anthocyanin microcapsules according to claim 8, characterized in that: Applications of the pH-responsive maquilli anthocyanin microcapsules in the food, health product, or pharmaceutical fields.

Images