A microcapsule based on tartary buckwheat whole plant extract and a preparation process thereof

Abstract

The present application belongs to the technical field of tartary buckwheat comprehensive processing, and provides a microcapsule based on tartary buckwheat whole plant extract and a preparation process thereof, wherein the microcapsule comprises core material and wall material in a mass ratio of 1:5-10, the core material is tartary buckwheat whole plant extract containing flavones; the wall material comprises first wall material and second wall material arranged outside the core material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch; the second wall material is sodium alginate, chitosan and pectin; the preparation process comprises the following steps: dissolving the first wall material in water to form a first embedding wall material liquid, then dispersing the core material in the first embedding wall material liquid, mixing uniformly and then sending to a spray drying equipment for spray drying to obtain first capsules; dissolving the second wall material in water to form a second embedding wall material liquid, spraying the second embedding wall material liquid on the surface of the first capsules, and after the film coating is stable, the microcapsule is obtained; and the microcapsule has good anti-gastric acid degradation performance and slow release performance.

Description

Technical Field

[0001] This invention relates to the field of comprehensive processing technology of buckwheat, and more specifically, to a microcapsule based on the whole plant extract of buckwheat and its preparation process. Background Technology

[0002] The main components of buckwheat extract are flavonoids, along with steroids, phenols, active proteins, and minerals. The primary flavonoid in buckwheat is rutin, which softens blood vessels, improves microcirculation, maintains capillary resistance, reduces permeability and fragility, promotes cell proliferation, and prevents blood cell aggregation. Buckwheat is rich in magnesium, which can slow heart rhythm and excitation conduction, increasing myocardial blood supply. Buckwheat extract also contains selenium, an essential trace element identified by the World Health Organization and currently the only recognized anti-cancer element. Selenium deficiency can cause dysfunction of vital organs, and medical experts at the American Cancer Institute point out that adequate selenium can prevent cancer. In the body, selenium combines with metals to form an unstable "metal-selenium-protein" complex, which helps to eliminate toxic elements such as lead and mercury from the body. Therefore, buckwheat extract offers numerous health benefits to humans. Currently, the application of buckwheat flavonoids in the market mainly involves extracting flavonoid compounds from buckwheat and adding them to products directly or indirectly. Because flavonoids have poor stability, microencapsulation technology is often used to encapsulate buckwheat flavonoids in target products to exert their physiological functions.

[0003] For example, Chinese patent CN108770948A discloses a glyceryl tartrate microcapsule with maltodextrin and cyclodextrin as wall materials. The DE value of the maltodextrin is limited to between 5 and 25. The DE value range is too wide, resulting in excessive dispersion of maltodextrin and poor encapsulation effect.

[0004] Chinese patent CN102948904A discloses a production technology for high-calcium buckwheat flavonoid instant beverages. It uses xanthan gum, β-cyclodextrin and sodium carboxymethyl cellulose to coat flavonoid extract. Xanthan gum has the characteristics of low concentration and high viscosity, which can easily affect the dispersibility of flavonoids. Sodium carboxymethyl cellulose solution is in a high viscosity state under neutral and alkaline conditions, which limits the processing conditions of the encapsulated product.

[0005] Therefore, there is an urgent need for an encapsulation wall material that has good encapsulation effect, maintains the activity of the core material and does not damage the nutritional components, and for microcapsules encapsulated with such an encapsulation wall material to exert a sustained-release effect after entering the human body, so as to improve the utilization rate and value of its nutritional components. Summary of the Invention

[0006] The purpose of this invention is to provide a microcapsule based on the whole plant extract of buckwheat and its preparation process, which has good resistance to gastric acid degradation and sustained-release properties; thereby greatly improving the activity, utilization rate and value of the nutrient components of buckwheat extract.

[0007] The embodiments of the present invention are achieved through the following technical solutions:

[0008] A microcapsule based on a whole-plant extract of tartary buckwheat comprises a core material and a wall material in a mass ratio of 1:5-10. The core material is a flavonoid-containing whole-plant extract of tartary buckwheat. The wall material comprises a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material. The first wall material is carrageenan and octenyl succinic anhydride modified porous starch. The second wall material is sodium alginate, chitosan, and pectin.

[0009] A process for preparing microcapsules based on whole buckwheat extract includes the following steps:

[0010] S1. Dissolve the first wall material in water to form the first embedded wall material liquid, then disperse the core material in the first embedded wall material liquid, mix well, and send it to the atomizer of the spray drying equipment for spray drying to obtain the first capsule;

[0011] S2. Dissolve the second wall material in water to form a second embedding wall material solution, spray the second embedding wall material solution on the surface of the first capsule, and obtain the second capsule after the coating stabilizes.

[0012] S3. Coat the surface of the second capsule evenly with beeswax. After the encapsulation stabilizes, the microcapsule is obtained.

[0013] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0014] 1. In this invention, the microcapsules encapsulate the core material using a layered encapsulation method: A first wall material, modified with carrageenan and octenyl succinic anhydride, is used to completely encapsulate the core material. This first wall material exhibits high specific volume, specific surface area, and adsorption capacity, and possesses a hollow porous structure. Furthermore, the modification process introduces hydrophobic groups to avoid affecting the bioactivity and integrity of the active ingredients such as flavonoids in the core material, thus maintaining the stability of these active ingredients. Based on the porous membrane structure constructed by the first wall material, a second wall material is then encapsulated. This not only facilitates the entry of sodium alginate and chitosan into the pores to crosslink with the modified porous starch to form a film, but also allows them to adsorb inside the modified porous starch and bind more tightly to the hydrophobic groups. This results in excellent resistance to gastric acid degradation, allowing most of the core material to smoothly enter the intestines. Simultaneously, it promotes the coating stability between the first and second wall materials, while also improving the encapsulation stability of the core material, preventing premature desorption after entering the acidic or alkaline environment of the gastrointestinal tract. On one hand, the outermost chitosan slowly dissolves in acidic solutions, causing the second wall material to slowly desorb, thus exposing the porous structure of the first wall material. Modified porous starch undergoes hydrolysis in acidic solutions, causing the starch pores to collapse, gradually releasing the adsorbed core material. This results in the microcapsules exhibiting excellent resistance to gastric acid degradation and sustained-release properties. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0016] The following is a detailed description of a microcapsule based on the whole plant extract of tartary buckwheat and its preparation method provided by an embodiment of the present invention.

[0017] A microcapsule based on a whole-plant extract of tartary buckwheat comprises a core material and a wall material in a mass ratio of 1:5-10. The core material is a flavonoid-containing whole-plant extract of tartary buckwheat. The wall material includes a first wall material disposed outside the core material and a second wall material disposed outside the first wall material, with the first and second wall materials disposed in equal proportions. The first wall material is carrageenan and octenyl succinic anhydride-modified porous starch; the second wall material is sodium alginate, chitosan, and pectin. By using a compound of sodium alginate, chitosan, and pectin as the outer wall material, better encapsulation with the first wall material, which has hydrophobic groups, is achieved, improving the stability of the microcapsule; simultaneously, the stability, antioxidant properties, and encapsulation efficiency of the wall material are improved.

[0018] On the one hand, this invention employs a layered coating process when preparing microcapsules to coat the outer surface of the core material. Carrageenan and octenyl succinic anhydride-modified porous starch are used as the first wall material to completely encapsulate the core material. This first wall material exhibits high specific volume, specific surface area, and adsorption capacity, and possesses a hollow porous structure. Furthermore, the modification process introduces hydrophobic groups to avoid affecting the bioactivity and integrity of the active ingredients such as flavonoids in the core material, thus maintaining the stability of these active ingredients. Based on the porous membrane structure constructed by the first wall material, a second wall material is then applied. This not only facilitates the entry of sodium alginate and chitosan into the pores to crosslink with the modified porous starch to form a film, but also allows them to adsorb inside the modified porous starch and bind with the hydrophobic groups. The tighter structure results in excellent resistance to gastric acid degradation, allowing most of the core material to enter the intestines smoothly. Simultaneously, it promotes the coating stability between the first and second wall materials, while also improving the encapsulation stability of the core material, preventing premature desorption after entering the acidic or alkaline environment of the gastrointestinal tract. On one hand, the outermost chitosan slowly dissolves in acidic solutions, causing the second wall material to slowly desorb, thus exposing the porous structure of the first wall material. Modified porous starch undergoes hydrolysis in acidic solutions, causing the starch pores to collapse, gradually releasing the adsorbed core material. This results in the microcapsules exhibiting excellent resistance to gastric acid degradation and sustained-release properties.

[0019] Finally, a superhydrophobic coating such as beeswax can be applied to the outermost layer to isolate it from the external environment and prevent it from absorbing water and disintegrating.

[0020] The preparation method of the octenyl succinic anhydride modified porous starch is as follows:

[0021] (1) Mix starch and buffer solution at a solid-liquid ratio of 1.5-2:1 g / mL and preheat in a water bath at 45-55℃ for 15-25 min. Add compound enzyme and react at 45-55℃ for 8-12 h, controlling the pH value of the reaction to be 5.8-6.2. After the reaction is completed, add 4% sodium hydroxide to terminate the reaction. After filtration and washing with distilled water, dry at 45-55℃ for 24 h and grind to obtain porous starch. The compound enzyme is α-amylase and saccharifying enzyme at a mass ratio of 1:4-6. The amount of compound enzyme is 2-4% of the starch amount.

[0022] (2) The porous starch obtained in (1) is mixed with distilled water to prepare a 30% porous starch emulsion. After stirring in a constant temperature water bath at 45-55℃ for 20-30 minutes, 3% sodium hydroxide is added until the pH of the solution reaches 8.5-9.0. Then, octenyl succinic anhydride is slowly added dropwise while stirring. Preferably, the octenyl succinic anhydride is diluted 3 times with anhydrous ethanol beforehand. The pH of the solution is controlled to be 8.4-8.6. The reaction is carried out under water bath conditions at 35-45℃ for 4 hours. After the reaction is completed, the solution is filtered, washed and neutralized with hydrochloric acid, washed several times with anhydrous ethanol, and dried at 45-55℃ for 24 hours to obtain the modified porous starch.

[0023] A process for preparing microcapsules based on whole buckwheat extract includes the following steps:

[0024] S1. Dissolve the first wall material in water to form the first embedded wall material liquid, then disperse the core material in the first embedded wall material liquid, mix well, and send it to the atomizer of the spray drying equipment for spray drying to obtain the first capsule;

[0025] S2. Dissolve the second wall material in water to form a second embedding wall material solution, spray the second embedding wall material solution on the surface of the first capsule, and obtain the second capsule after the coating stabilizes.

[0026] S3. Coat the surface of the second capsule evenly with beeswax. After the encapsulation stabilizes, the microcapsule is obtained.

[0027] In S1, during spray drying: the inlet air temperature is 180-195℃, the outlet air temperature is 80-95℃, the rotation speed is 10-15r / min, and the feed rate is 10-20mL / min.

[0028] In S1, the preparation method of the core material is as follows: after cleaning and removing impurities from buckwheat, soak it to germinate and obtain buckwheat seedlings. Extract the buckwheat seedlings with 75%-85% ethanol, controlling the liquid-to-solid ratio at 75-85:1. After ultrasonic extraction for 20-30 minutes, centrifuge for 10-20 minutes and collect the supernatant to obtain the core material.

[0029] Example 1

[0030] A microcapsule based on a whole-plant extract of tartary buckwheat comprises a core material and a wall material in a mass ratio of 1:8. The core material is a flavonoid-containing whole-plant extract of tartary buckwheat. The wall material comprises a first wall material disposed outside the core material and a second wall material disposed outside the first wall material. The first wall material and the second wall material are disposed in equal proportions. The first wall material is a porous starch modified with carrageenan and octenyl succinic anhydride in a mass ratio of 1:3. The second wall material is sodium alginate, chitosan, and pectin in a mass ratio of 5:3:1.

[0031] The preparation method of octenyl succinic anhydride modified porous starch is as follows:

[0032] (1) Starch and acetate-sodium acetate buffer were mixed at a solid-liquid ratio of 1.8:1 g / mL and preheated in a water bath at 50℃ for 20 min. A compound enzyme was added and reacted at 50℃ for 10 h, with the pH controlled at 6. After the reaction was completed, 4% sodium hydroxide was added to terminate the reaction. After filtration and washing with distilled water, the mixture was dried at 50℃ for 24 h and then ground to obtain porous starch. The compound enzyme consisted of α-amylase and saccharifying enzyme in a mass ratio of 1:5, and the amount of compound enzyme was 3% of the amount of porous starch.

[0033] (2) The porous starch obtained in step (1) is mixed with distilled water to prepare a 30% porous starch emulsion. After stirring in a constant temperature water bath at 50°C for 20 minutes, 3% sodium hydroxide is added until the pH of the solution reaches 8.5. Then, octenyl succinic anhydride is slowly added dropwise while stirring. Preferably, the octenyl succinic anhydride is diluted 3 times with anhydrous ethanol beforehand. The pH of the solution is controlled to be 8.4-8.6. The reaction is carried out in a water bath at 40°C for 4 hours. After the reaction is completed, the solution is filtered, washed with hydrochloric acid and neutralized, then washed multiple times with anhydrous ethanol, and dried at 50°C for 24 hours to obtain the modified porous starch.

[0034] The preparation process of the above microcapsules includes the following steps:

[0035] S1. Preparation of core material: After cleaning and removing impurities from buckwheat, soak it to germinate and obtain buckwheat seedlings. Extract the buckwheat seedlings with 80% ethanol and control the liquid-to-solid ratio to 80:1. After ultrasonic extraction for 20 minutes, centrifuge for 10 minutes and take the supernatant, which is the embedded core material.

[0036] S2. Dissolve the first wall material in distilled water at 60℃ to prepare a 5% first embedding wall material solution. Then, disperse the embedding core material obtained in S1 in the first embedding wall material solution, mix well, and send it to the atomizer of the spray drying equipment for spray drying. During spray drying: the inlet air temperature is 185℃, the outlet air temperature is 85℃, the rotation speed is 10r / min, and the feed rate is 15mL / min; the first capsule is obtained.

[0037] S3. Dissolve the second wall material in distilled water at 60°C to prepare a 5% second embedding wall material solution. Spray the second embedding wall material solution onto the surface of the first capsule. After the coating stabilizes, the second capsule is obtained.

[0038] S4. Coat the surface of the second capsule evenly with beeswax. After the encapsulation stabilizes, the microcapsule is obtained.

[0039] Example 2

[0040] The difference between this embodiment and Embodiment 1 is that: a microcapsule based on the whole plant extract of tartary buckwheat includes a core material and a wall material in a mass ratio of 1:6, wherein the core material is the whole plant extract of tartary buckwheat containing flavonoids; the wall material includes a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch in a mass ratio of 1:4; the second wall material is sodium alginate, chitosan and pectin in a mass ratio of 4:3:1.

[0041] Example 3

[0042] The difference between this embodiment and Embodiment 1 is that: a microcapsule based on the whole plant extract of tartary buckwheat includes a core material and a wall material in a mass ratio of 1:7, wherein the core material is a flavonoid-containing whole plant extract of tartary buckwheat; the wall material includes a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch in a mass ratio of 1:2.5; the second wall material is sodium alginate, chitosan and pectin in a mass ratio of 3:2:1.

[0043] Example 4

[0044] The difference between this embodiment and Embodiment 1 is that: a microcapsule based on the whole plant extract of tartary buckwheat includes a core material and a wall material in a mass ratio of 1:9, wherein the core material is the whole plant extract of tartary buckwheat containing flavonoids; the wall material includes a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch in a mass ratio of 1:2; the second wall material is sodium alginate, chitosan and pectin in a mass ratio of 6:4:1.

[0045] Example 5

[0046] The difference between this embodiment and Embodiment 1 is that: a microcapsule based on the whole plant extract of tartary buckwheat includes a core material and a wall material in a mass ratio of 1:10, wherein the core material is the whole plant extract of tartary buckwheat containing flavonoids; the wall material includes a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch in a mass ratio of 1:5; the second wall material is sodium alginate, chitosan and pectin in a mass ratio of 6:2:1.

[0047] Example 6

[0048] The difference between this embodiment and Embodiment 1 is that: a microcapsule based on the whole plant extract of tartary buckwheat includes a core material and a wall material in a mass ratio of 1:6, wherein the core material is a flavonoid-containing whole plant extract of tartary buckwheat; the wall material includes a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch in a mass ratio of 1:3.5; the second wall material is sodium alginate, chitosan and pectin in a mass ratio of 4.5:2.5:1.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that it does not contain the first wall material.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 1 is that the first wall material is carrageenan and starch.

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 1 is that it does not contain a second wall material.

[0055] The microcapsules prepared in Examples 1-6 and Comparative Examples 1-3 were used as experimental groups; their encapsulation efficiency, hygroscopicity and sustained-release performance were tested respectively.

[0056] Experimental Example 1 - Embedding Rate

[0057] (1) Determination of flavonoids on the surface of microcapsules

[0058] Weigh 0.2g of dried buckwheat flavonoids from each experimental group, add anhydrous ethanol at a ratio of 1:30, shake thoroughly, centrifuge (5000r / min, 10min), take 1mL of supernatant, make up to 10mL, and measure its absorbance using the AlCl3 method to obtain the content of flavonoids on the surface of the microcapsules.

[0059] (2) Determination of total flavonoid content in microcapsules

[0060] Weigh 0.2g of dried buckwheat flavonoids from microcapsules, add 70% ethanol at a ratio of 1:30, sonicate at 40℃ for 30min, centrifuge (5000r / min, 10min), take 1mL of supernatant, make up to 10mL, and measure its absorbance using the AlCl3 method to obtain the total flavonoid content of the microcapsules.

[0061] (3) Determination of embedding rate

[0062] The encapsulation efficiency was calculated by comparing the content of flavonoids on the surface of the microcapsules obtained in (1) with the total flavonoid content of the microcapsules obtained in (2). The formula is shown below:

[0063] Encapsulation rate (%) = (BA) / B * 100%,

[0064] Where A represents the content of flavonoids on the surface of the microcapsules, and B represents the total flavonoid content of the microcapsules; the experimental results are shown in Table 1.

[0065] Table 1. Effect of different encapsulation wall materials on the encapsulation efficiency of microcapsule buckwheat flavonoids

[0066] Example 1 94.3 Example 2 93.6 Example 3 93.1 Example 4 93.7 Example 5 94.5 Example 6 93.9 Comparative Example 1 64.1 Comparative Example 2 78.7 Comparative Example 3 85.3

[0067] As shown in Table 1, the encapsulation rates of the microcapsules prepared in the embodiments of the present invention are all higher than those of the comparative examples. This is mainly because the present invention performs layered coating on the core material, and the first wall material introduces hydrophobic groups and forms a porous membrane structure, which allows the second wall material to enter the above-mentioned pores to react with ions to crosslink and form a film, and adsorb into the modified porous starch and bind more tightly with the hydrophobic groups, thus achieving a better encapsulation effect.

[0068] Experimental Example 2 - Hygroscopicity

[0069] Weigh 1g of each microcapsule sample from each experimental group and place it in an airtight plastic container filled with saturated NaCl solution (75% RH) at 25℃. Weigh the samples after 7 days and calculate the hygroscopicity of the samples using the following formula.

[0070] Hygroscopicity (%) = (M1-M2) / M2 × 100%

[0071] Where: M1: mass of the sample after moisture absorption, g; M2: initial mass of the sample, g; the experimental results are shown in Table 2.

[0072] Table 2 Results of hygroscopicity measurement in different experimental groups

[0073] Example 1 21.2 Example 2 21.6 Example 3 22.1 Example 4 21.8 Example 5 21.4 Example 6 22.0 Comparative Example 1 62.1 Comparative Example 2 57.4 Comparative Example 3 52.8

[0074] As shown in Table 2, the hygroscopicity of the microcapsules prepared in the embodiments of the present invention is lower than that of the comparative example, which proves that good encapsulation can prevent active substances such as phenols from directly contacting moisture in the air, thereby reducing the hygroscopicity of the product, which is beneficial to the storage stability of the product and extending its shelf life.

[0075] Experimental Example 3 - Sustained-release performance

[0076] Simulated gastric juice: Weigh 2.0g sodium chloride (NaCl), 7.0mL HCl (mass fraction 36%) and 10g pepsin and dissolve them in 1L distilled water to prepare a simulated gastric acid solution. Adjust the pH of the solution to 1.2 and store the obtained simulated gastric juice at 4℃ for later use.

[0077] Simulated intestinal fluid: Accurately weigh 6.8g of potassium dihydrogen phosphate and place it in a beaker. Add 500mL of deionized water to dissolve it completely. Adjust the pH to 6.8 with 0.4% NaOH solution. Separately dissolve 10g of trypsin in deionized water. Combine the two solutions and bring the volume to 1000mL. Store the resulting simulated intestinal fluid at 4℃ for later use.

[0078] Weigh approximately 0.1 g of microcapsule sample into a 50 mL centrifuge tube containing simulated gastric fluid. Incubate at 37°C in a shaking bath for 4 hours. Every hour, collect 3 mL of the supernatant to detect flavonoid release. Add an equal volume of simulated gastric fluid. Adjust the sample pH to 6.8 to terminate gastric digestion. Add 50 mL of simulated intestinal fluid and incubate at 37°C in a shaking bath for 6 hours. Every hour, collect 3 mL of the supernatant to detect flavonoid release. Add an equal volume of simulated intestinal fluid. Calculate the cumulative flavonoid release rate of the microcapsules using the following formula.

[0079] Cumulative flavonoid release rate (%) = Flavonoid content released in simulated gastrointestinal fluid / (Weight of microcapsules * Encapsulation rate) * 100%;

[0080] The experimental results are shown in Table 3. From the results in Table 3, we can see that:

[0081] Table 3. Results of release rate determination in different experimental groups

[0082]

[0083]

[0084] As shown in Table 3, during the simulated gastric juice stage (0–4 h), the flavonoid release rate of the microcapsules in each experimental group increased slowly over time. Among them, the flavonoid release rate of the microcapsules prepared in the embodiments of the present invention was less than 10% in the gastric juice. During the intestinal digestion stage (4–10 h), the flavonoid release rate of the microcapsules in each experimental group increased rapidly over time. At the end of the intestinal digestion stage, the flavonoid release rate of the microcapsules was higher than 90%, indicating that the intestinal digestion stage is more conducive to the release of the microcapsule core material. The comparative examples all performed poorly, maintaining a relatively stable state during the intestinal fluid stage, and exhibiting low flavonoid release rates. In Comparative Example 1, due to the lack of protection from the first wall material, the starch was essentially decomposed during the gastric fluid stage, resulting in the rapid release of the internal core material. However, it remained relatively stable during the intestinal fluid stage, with minimal release. In Comparative Example 2, the starch was not modified, resulting in poor synergy with the second wall material and an inability to effectively exert its anti-gastric acid degradation and sustained-release properties. In Comparative Example 3, the lack of protection from the second wall material caused the first wall material to hydrolyze during the gastric fluid stage, leading to the collapse of starch pores and the rapid release of the internal core material.

[0085] This is mainly because the second wall material slowly dissolves in an acidic environment, exposing the first wall material with its porous structure. The modified porous starch undergoes hydrolysis in the acidic solution, causing the starch pores to collapse and the core material adsorbed inside to be gradually released. However, because sodium alginate and chitosan can enter the pores of the first wall material and cross-link with ions to form a film, and are adsorbed inside the modified porous starch and tightly bound to hydrophobic groups, the release during the gastric juice stage is relatively small, approximately 10%. Therefore, the microcapsules of this embodiment exhibit good resistance to gastric acid degradation in an acidic environment, allowing most of the active substances in the core material to smoothly enter the intestines. When entering the intestinal juice stage, the second wall material is basically completely decomposed, exposing the first wall material, which then undergoes hydrolysis, and the core material adsorbed inside is gradually released, thus enabling the microcapsules to exhibit good resistance to gastric acid degradation and sustained-release properties.

[0086] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A microcapsule based on a whole-plant extract of tartary buckwheat, characterized in that, It includes a core material and a wall material in a mass ratio of 1:5-10, wherein the core material is a whole plant extract of tartary buckwheat containing flavonoids; The wall material includes a first wall material disposed on the outside of the core material and a second wall material disposed on the outside of the first wall material; the first wall material is carrageenan and octenyl succinic anhydride modified porous starch; the second wall material is sodium alginate, chitosan and pectin; The preparation method of the octenyl succinic anhydride modified porous starch is as follows: (1) After mixing starch with buffer solution, heat for a period of time, add compound enzyme and react for a period of time, then add alkali solution to terminate the reaction, dry and grind for later use; the compound enzyme is α-amylase and saccharifying enzyme with a mass ratio of 1:4-6. (2) The porous starch obtained in (1) is prepared into a porous starch emulsion. After heating, an alkaline solution is added to adjust the pH value of the solution to 8.5-9.

0. Then, octenyl succinic anhydride is slowly added dropwise while stirring, and the pH value of the solution is controlled to 8.4-8.

6. After heating and reacting for a period of time, the modified porous starch is obtained by neutralization, washing and drying.

2. The microcapsules based on whole buckwheat extract according to claim 1, characterized in that, The mass ratio of carrageenan and modified porous starch in the first wall material is 1:2-5; the mass ratio of sodium alginate, chitosan and pectin in the second wall material is 3-6:2-4:

1.

3. The microcapsules based on whole buckwheat extract according to claim 1, characterized in that, The pH value of the buffer solution is 5.3-5.

5.

4. The microcapsules based on whole buckwheat extract according to claim 1, characterized in that, The dosage of the compound enzyme is 2-4%.

5. The microcapsule based on whole buckwheat extract according to claim 1, characterized in that, In step (1), the solid-liquid ratio of starch to buffer is 1.5-2:1 g / mL; in step (2), the amount of octenyl succinic anhydride added is 2-4% of the porous starch emulsion.

6. The microcapsules based on the whole plant extract of tartary buckwheat according to claim 1, characterized in that, In step (1), the reaction temperature is 45-55℃, the reaction time is 8-12h, and the reaction pH is 5.8-6.2; in step (2), the reaction temperature is 35-45℃, and the reaction time is 3-5h.

7. A microcapsule preparation process according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Dissolve the first wall material in water to form the first embedded wall material liquid, then disperse the core material in the first embedded wall material liquid, mix well, and send it to the atomizer of the spray drying equipment for spray drying to obtain the first capsule; S2. Dissolve the second wall material in water to form a second embedding wall material solution, spray the second embedding wall material solution on the surface of the first capsule, and obtain the second capsule after the coating stabilizes. S3. Coat the surface of the second capsule evenly with beeswax. After the encapsulation stabilizes, the microcapsule is obtained.

8. A microcapsule preparation process according to claim 7, characterized in that, In S1, during spray drying: the inlet air temperature is 180-195℃, the outlet air temperature is 80-95℃; the rotation speed is 10-15 r / min, and the feed rate is 10-20 mL / min.

9. A microcapsule preparation process according to claim 7, characterized in that, In S1, the method for preparing the core material is as follows: After cleaning and removing impurities from the buckwheat, soak it to germinate and obtain buckwheat seedlings. Extract the buckwheat seedlings with 75%-85% ethanol, controlling the liquid-to-solid ratio at 75-85:

1. After ultrasonic extraction for 20-30 minutes, centrifuge for 10-20 minutes and collect the supernatant to obtain the core material.

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