Vitamin K2 composite micro-capsule system with stomach protection and intestine slow release functions as well as preparation method and application of vitamin K2 composite micro-capsule system

Abstract

The invention discloses a vitamin K2 composite micro-capsule system with stomach protection and intestine slow release functions and a preparation method and application thereof, the vitamin K2 composite micro-capsule system with stomach protection and intestine slow release functions comprises three layers, namely a core layer, a middle layer and an outer layer from inside to outside in sequence; the core layer is formed by coating vitamin K2 with a zein-lac hydrophobic core, the middle layer is a pea protein-pectin electrostatic compound, and the outer layer is sodium alginate and chitosan double-network gel. The micro-capsule system provided by the invention can be tightly combined in a gastric acid environment after being orally taken, the release of active ingredients in the stomach is reduced, and then the micro-capsule system stays at intestinal mucosa for a long time and slowly releases contents, so that the functions of the micro-capsule system are slowly presented outside, the half-life period is prolonged, and the action effect is improved. Vitamin K2 directly or indirectly participates in and regulates various physiological processes related to health, and plays an important role in the aspects of maintaining bone health, preventing cardiovascular diseases, protecting nerves, improving metabolism and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanocarriers, and in particular relates to a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release functions, and a preparation method and application thereof. Background Art

[0002] Vitamin K compounds are a group of fat-soluble vitamins found in nature with a 2-methyl-1,4-naphthoquinone parent structure. They are an important family of nutrients. Natural vitamin K includes vitamin K1 and vitamin K2. Vitamin K2, primarily found in natto, meat, and cheese, has polymerized isoprene side chains and is divided into subtypes based on the number of isoprene groups. These include tetraene-methyl-menaquinone (MK-4), heptaene-methyl-menaquinone (MK-7), and nonene-methyl-menaquinone (MK-9), with MK-7 being a representative component.

[0003] As clinical research on vitamin K2 continues to deepen, its significant impact on the body's normal physiological functions is gradually gaining more attention. In terms of maintaining bone health, vitamin K2 can promote bone formation by stimulating osteoblast differentiation; maintain a normal bone mineralization rate in the skeleton by converting glutamic acid residues of osteocalcin (OC) to γ-carboxyglutamic acid residues; and inhibit bone resorption through its anti-catabolic activity (reducing osteoclast differentiation and inhibiting osteoblast apoptosis). Vitamin K2 is used as a drug in the clinical treatment of osteoporosis to promote the growth of bone bud cells, inhibit osteoclast production, regulate bone metabolism markers, maintain bone homeostasis, and improve patients' bone health.

[0004] In terms of cardiovascular disease prevention, vitamin K2 can inhibit cardiovascular calcification by activating matrix Gla protein, reducing the risk of arteriosclerosis / arterial calcification and coronary heart disease (CHD). Matrix Gla protein is a natural, potent calcification inhibitor that requires carboxylation by vitamin K-dependent gamma carboxylase to become active. Vitamin K2 supplementation can maintain the presence of inhibitory factors for vascular calcification in the body.

[0005] In addition, vitamin K2 can also participate in protecting nerves, improving metabolism and inhibiting tumor growth through various mechanisms such as inhibiting cell apoptosis signaling pathways, reducing inflammatory responses, protecting mitochondrial function, improving insulin resistance and promoting cell autophagy, playing an important role in the treatment of related diseases.

[0006] However, vitamin K2 is a fat-soluble vitamin, making it difficult to evenly incorporate into water-soluble products. This limits its application areas and requires the use of high-quality fats to aid absorption and achieve optimal conversion. Furthermore, vitamin K2 is sensitive to ultraviolet light and alkalis, easily degrading in the presence of light and becoming inactive during long-term storage. This requires process improvements to stabilize it. Because it regulates calcium metabolism, it is often mixed with minerals such as calcium and magnesium, which are essential for calcium metabolism. However, vitamin K2 readily decomposes upon contact with these minerals, resulting in unstable levels in the product.

[0007] Microencapsulation technology utilizes a suitable polymer as a carrier, encapsulating a target substance (core or inner phase) within a semipermeable membrane (wall or outer phase) to form a microparticle dispersion system. The shielding function of the wall or outer phase protects the core or inner phase, enhancing product stability. Subsequently, under certain external stimuli or sustained-release mechanisms, the target substance's functions are re-expressed externally, achieving sustained, controlled, and prolonged release.

[0008] Therefore, there is an urgent need to develop a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release properties. Microencapsulation technology can effectively isolate vitamin K2 from the external environment, protecting it from the effects of light, air, pH, and minerals, effectively addressing vitamin K2 instability and maintaining product effectiveness. Furthermore, microencapsulated vitamin K2 can be dispersed in water, offering unrestricted use and stable performance in a variety of products, including water-soluble solutions. Summary of the Invention

[0009] In order to solve the problems raised in the above background technology, the purpose of the present invention is to provide a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function and its preparation method and application.

[0010] The vitamin K2 composite microcapsule system of the present invention has gastric protection and intestinal sustained release functions. First, vitamin K2 is wrapped with a zein-lac hydrophobic core as the core layer. The shielding effect of the capsule wall protects vitamin K2 from the influence of light, air, pH value, and minerals. Secondly, a pea protein-pectin electrostatic complex is used as the middle layer to form a submicron-level complex through electrostatic adsorption. The pea protein-pectin composite wall material structure is more compact, which has a better protection effect on vitamin K2. Finally, the outer layer uses sodium alginate (SA) and chitosan (CS) through Ca 2+Cross-linking and hydrogen bonding form a double network gel, which improves mechanical strength and adhesion, can reach a specific part (intestinal mucosa) to gather, and achieve the purpose of controlled release. The three-layer composite embedding system of vitamin K2 provided by the present invention can be tightly combined in a gastric acid environment after oral administration, reduce the release of active ingredients in the stomach, and then stay in the intestinal mucosa for a long time, slowly release the contents, so that its function is slowly presented to the outside, prolonging the half-life and improving the effect. Vitamin K2 directly or indirectly participates in and regulates a variety of physiological processes related to health, and plays an important role in maintaining bone health, preventing cardiovascular disease, protecting nerves, improving metabolism, etc. Zein and pea protein can also increase nutrition, promote health, and meet the various needs of the body.

[0011] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: on the one hand, the present invention provides a microcapsule system, comprising three layers, namely, a core layer, an intermediate layer and an outer layer from the inside to the outside;

[0012] The core layer is a zein-lac hydrophobic core, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS).

[0013] On the other hand, the present invention provides a use of the above-mentioned microcapsule system as a vitamin K2 embedding system.

[0014] On the other hand, the present invention provides a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function, comprising three layers, namely, a core layer, a middle layer and an outer layer from the inside to the outside;

[0015] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS).

[0016] Furthermore, based on the total mass percentage of raw materials as 100%, the following raw material components are included: vitamin K2 is 5% to 20%, zein is 5% to 20%, shellac is 5% to 15%, pea protein is 5% to 20%, low-ester pectin is 5% to 15%, sodium alginate is 10% to 30%, calcium chloride (CaCl2) is 5% to 15%, and chitosan is 5% to 15%.

[0017] Furthermore, the vitamin K2 is in the MK-7 configuration.

[0018] In another aspect, the present invention provides a method for preparing the above-mentioned vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function, comprising the following steps:

[0019] (1) Zein is fully dissolved in a solvent to obtain a zein solution, vitamin K2 is added to the zein solution and stirred to obtain a mixed solution, water is then added to the mixed solution, emulsified using a high-pressure homogenizer, and then rotary evaporated to obtain a rotary evaporated emulsion, shellac is dissolved in water to obtain a shellac aqueous solution, and then the rotary evaporated emulsion is added to the shellac aqueous solution and the pH of the system is adjusted to 2.5-3.5, and stirring is continued for a period of time to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule;

[0020] (2) dissolving pea protein in water to obtain a pea protein aqueous solution, adjusting the pH of the pea protein aqueous solution to 3-4.5, adding the nano-scale zein-based vitamin K2 oil microcapsule core prepared in step (1) to the pea protein aqueous solution with a pH of 3-4.5, stirring evenly, adding low-ester pectin, and then homogenizing using a microfluidizer to obtain vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure;

[0021] (3) Sodium alginate is dissolved in water to obtain a sodium alginate aqueous solution, the pH of the sodium alginate aqueous solution is adjusted to 3-4.5, the vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure prepared in step (2) are added to the sodium alginate aqueous solution with a pH of 3-4.5 and stirred to obtain an intermediate mixed solution, calcium chloride and chitosan are dissolved in water and stirred to obtain a calcium chloride chitosan aqueous solution, and then the intermediate mixed solution is squeezed into the stirring calcium chloride chitosan aqueous solution using a vibrating nozzle to obtain vitamin K2 oil particles with a uniform three-layer protective structure, i.e., a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained release function.

[0022] Furthermore, the solvent in step (1) is selected from an ethanol aqueous solution with a volume percentage of 60% to 80%;

[0023] The emulsification pressure in step (1) is 600 to 1000 bar, and the number of emulsifications is 1 to 5 times;

[0024] The rotary evaporation in step (1) is a reduced pressure rotary evaporation at 65-75° C., and the rotary evaporation time is 5-15 minutes;

[0025] The stirring time in step (1) is 30 to 50 minutes.

[0026] Furthermore, the homogenization pressure in step (2) is 10,000 to 15,000 psi, and the number of homogenizations is 1 to 5 times.

[0027] Furthermore, the frequency of the vibrating nozzle in step (3) is 800 to 1000 Hz.

[0028] In another aspect, the present invention provides a use of any of the above-mentioned vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions in the preparation of drugs for maintaining bone health, preventing cardiovascular diseases, protecting nerves, and improving metabolism.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Zein has strong hydrophobic properties, while shellac has strong adhesiveness and plasticity. The combination of the two improves the mechanical properties, stability, and emulsification properties of zein, enhances the biocompatibility of shellac, and combines the excellent properties of both. In addition, the hydrophobicity of zein combined with the pH sensitivity of shellac can achieve zero gastric release and intestinal targeted release.

[0031] (2) Compared with soy protein, pea protein has good solubility and stirring stability, but pea protein has low surface charge, few disulfide bonds, and low mechanical strength. Pectin can interact non-covalently with pea protein, stabilize the protein gel network, improve flexibility and ductility, and achieve high activity retention. The retention rate is higher than that of the gum arabic system. The pea protein-pectin electrostatic complex can also control release with pH changes. In the gastric acid environment (pH 2.0-3.5), the positively charged pea protein tightly binds to the negatively charged pectin, shrinking the pores; in the intestine (pH 6.5-7.5), the charge of pea protein is reversed, and the complex dissociates and releases the contents.

[0032] (3) Chitosan and sodium alginate are both natural polysaccharides with good biocompatibility. Sodium alginate contains a large number of carboxyl and hydroxyl functional groups. Chitosan is a positively charged polymer compound. The coacervate formed by chitosan and sodium alginate can effectively protect the core material from oxidation. The positive charge of chitosan enables it to undergo electrostatic adsorption with negatively charged cell surfaces or targeting ligands. By utilizing chitosan's affinity for mucosa and its selectivity for specific sites, the tissue targeting of microcapsules can be improved and their residence time at the target site can be prolonged.

[0033] (4) The degradation products of the microcapsule system provided by the present invention have low toxicity and are good carriers of active molecules. When used as drug carriers, they have a high encapsulation rate, can remain stable in the body, and are not easy to rupture, ensuring the effective loading and release of vitamin K2 in the body, while increasing nutrition, promoting health, and not easily causing inflammatory reactions.

[0034] (5) Adopting innovative technology: anti-solvent precipitation-high-pressure micro-jet-vibration co-extrusion three-step method. Anti-solvent precipitation does not require complex equipment and tedious operation steps and is easy to implement; high-pressure micro-jet homogenizer can achieve efficient dispersion and homogenization. Compared with traditional homogenization technology, it can achieve a narrower particle size distribution, higher stability, and less prone to precipitation or stratification; vibration co-extrusion can make the material more compact during the extrusion process, improving the molding quality. The three-step method combines the advantages of each technology, making the entire preparation process more efficient and controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a graph showing the vitamin K2 retention rate of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function prepared in Examples 1 to 4 of the present invention and Comparative Examples 1 to 6 after 15 minutes, 60 minutes, and 120 minutes in simulated gastric fluid;

[0036] Figure 2 This is a graph showing the vitamin K2 retention rates of the vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1 to 4 of the present invention and Comparative Examples 1 to 6 after 15 minutes, 60 minutes, and 120 minutes in simulated intestinal fluid. DETAILED DESCRIPTION

[0037] In order to better understand the content of the present invention, the content of the present invention is further described below in conjunction with specific implementation methods, but the protection content of the present invention is not limited to the following embodiments.

[0038] Example 1

[0039] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function includes three layers, namely, a core layer, a middle layer, and an outer layer from the inside to the outside;

[0040] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS);

[0041] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 20% vitamin K2, 10% zein, 10% shellac, 10% pea protein, 10% low-ester pectin, 20% sodium alginate, 10% CaCl2, and 10% chitosan.

[0042] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0043] (1) 10% zein was dissolved in 100 mL of 70% ethanol aqueous solution by volume, and then stirred for 0.5 h to obtain a zein solution. 20% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified four times at a pressure of 800 bar using a high-pressure homogenizer. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 10 min to obtain a rotary emulsion. 10% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 3.5 using a hydrochloric acid solution. The mixture was stirred for 40 min to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule.

[0044] (2) 10% pea protein was dissolved in 100 mL of water to obtain a pea protein aqueous solution, the pH of the pea protein aqueous solution was adjusted to 3.5, the nanoscale zein-based vitamin K2 oil microcapsule core prepared in step (1) was added to the pea protein aqueous solution with a pH of 3.5 and stirred evenly, and then 10% low-ester pectin was added. Subsequently, a microfluidizer was used to homogenize the solution at a pressure of 15,000 psi for 3 times to obtain vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure;

[0045] (3) 20% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, and the pH of the sodium alginate aqueous solution was adjusted to 3.5. The vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure prepared in step (2) were added to the sodium alginate aqueous solution with a pH of 3.5, and stirred for 0.5 h to obtain an intermediate mixed solution. 10% CaCl2 and 10% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan aqueous solution. Subsequently, a vibrating nozzle was used to squeeze the intermediate mixed solution into the stirred CaCl2-chitosan aqueous solution at a frequency of 1000 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0046] Example 2

[0047] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function includes three layers, namely, a core layer, a middle layer, and an outer layer from the inside to the outside;

[0048] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS);

[0049] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 20% of vitamin K2, 7% of zein, 13% of shellac, 15% of pea protein, 5% of low-ester pectin, 30% of sodium alginate, 5% of CaCl2, and 5% of chitosan.

[0050] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0051] (1) 7% zein was dissolved in 100 mL of 60% ethanol aqueous solution by volume, and then stirred for 0.5 h to obtain a zein solution. 20% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified once using a high-pressure homogenizer at a pressure of 1000 bar. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 15 min to obtain a rotary emulsion. 13% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 2.5 using a hydrochloric acid solution. The mixture was stirred for 50 min to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule.

[0052] (2) 15% pea protein was dissolved in 100 mL of water to obtain a pea protein aqueous solution, the pH of the pea protein aqueous solution was adjusted to 4.5, the nanoscale zein-based vitamin K2 oil microcapsule cores prepared in step (1) were added to the pea protein aqueous solution with a pH of 4.5 and stirred evenly, and then 5% low-ester pectin was added. Subsequently, a microfluidizer was used to homogenize the solution at a pressure of 13,000 psi for 5 times to obtain vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure;

[0053] (3) 30% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, and the pH of the sodium alginate aqueous solution was adjusted to 4.5. The vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure prepared in step (2) were added to the sodium alginate aqueous solution with a pH of 4.5, and stirred for 0.5 h to obtain an intermediate mixed solution. 5% CaCl2 and 5% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan aqueous solution. Subsequently, the intermediate mixed solution was squeezed into the stirred CaCl2-chitosan aqueous solution using a vibrating nozzle at a frequency of 900 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0054] Example 3

[0055] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function includes three layers, namely, a core layer, a middle layer, and an outer layer from the inside to the outside;

[0056] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS);

[0057] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 15% of vitamin K2, 20% of zein, 5% of shellac, 5% of pea protein, 15% of low-ester pectin, 10% of sodium alginate, 15% of CaCl2, and 15% of chitosan.

[0058] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0059] (1) 20% zein was dissolved in 100 mL of 80% ethanol aqueous solution by volume, and then stirred for 0.5 h to obtain a zein solution. 15% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified three times at a pressure of 900 bar using a high-pressure homogenizer. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 5 min to obtain a rotary emulsion. 5% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 3 using a hydrochloric acid solution. The mixture was stirred for 30 min to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule.

[0060] (2) 5% pea protein was dissolved in 100 mL of water to obtain a pea protein aqueous solution, and the pH of the pea protein aqueous solution was adjusted to 3. The nanoscale zein-based vitamin K2 oil microcapsule cores prepared in step (1) were added to the pea protein aqueous solution with a pH of 3 and stirred evenly. 15% low-ester pectin was then added, and the mixture was homogenized once using a microfluidizer at a pressure of 10,000 psi to obtain vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure.

[0061] (3) 10% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, and the pH of the sodium alginate aqueous solution was adjusted to 3. The vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure prepared in step (2) were added to the sodium alginate aqueous solution with a pH of 3, and stirred for 0.5 h to obtain an intermediate mixed solution. 15% CaCl2 and 15% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan aqueous solution. Subsequently, a vibrating nozzle was used to squeeze the intermediate mixed solution into the stirred CaCl2-chitosan aqueous solution at a frequency of 800 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0062] Example 4

[0063] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function includes three layers, namely, a core layer, a middle layer, and an outer layer from the inside to the outside;

[0064] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS);

[0065] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 5% vitamin K2, 5% zein, 15% shellac, 20% pea protein, 12% low-ester pectin, 25% sodium alginate, 6% CaCl2, and 12% chitosan.

[0066] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0067] (1) 5% zein was dissolved in 100 mL of 75% ethanol aqueous solution, and then stirred for 0.5 h to obtain a zein solution. 5% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified 5 times at a pressure of 600 bar using a high-pressure homogenizer. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 8 min to obtain a rotary emulsion. 15% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 3.5 using a hydrochloric acid solution. The mixture was stirred for 45 min to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule.

[0068] (2) 20% pea protein was dissolved in 100 mL of water to obtain a pea protein aqueous solution, and the pH of the pea protein aqueous solution was adjusted to 4. The nanoscale zein-based vitamin K2 oil microcapsule cores prepared in step (1) were added to the pea protein aqueous solution with a pH of 4 and stirred evenly. 12% low-ester pectin was then added, and the mixture was homogenized twice using a microfluidizer at a pressure of 12,000 psi to obtain vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure.

[0069] (3) 25% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, and the pH of the sodium alginate aqueous solution was adjusted to 4. The vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure prepared in step (2) were added to the sodium alginate aqueous solution with a pH of 4, and stirred for 0.5 h to obtain an intermediate mixed solution. 6% CaCl2 and 12% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan aqueous solution. Subsequently, a vibrating nozzle was used to squeeze the intermediate mixed solution into the stirred CaCl2-chitosan aqueous solution at a frequency of 950 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0070] Comparative Example 1

[0071] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function includes two layers, namely, a core layer and an outer layer from the inside to the outside;

[0072] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, and the outer layer is a pea protein-pectin electrostatic complex;

[0073] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 20% vitamin K2, 20% zein, 20% shellac, 20% pea protein, and 20% low-ester pectin.

[0074] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0075] (1) 20% zein was dissolved in 100 mL of 70% ethanol aqueous solution by volume, and then stirred for 0.5 h to obtain a zein solution. 20% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified four times at a pressure of 800 bar using a high-pressure homogenizer. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 10 min to obtain a rotary emulsion. 20% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 3.5 using a hydrochloric acid solution. The mixture was stirred for 40 min to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule.

[0076] (2) 20% pea protein was dissolved in 100 mL of water to obtain a pea protein aqueous solution, the pH of the pea protein aqueous solution was adjusted to 3.5, the nanoscale zein-based vitamin K2 oil microcapsule core prepared in step (1) was added to the pea protein aqueous solution and stirred evenly, and then 20% low-ester pectin was added, followed by homogenization three times using a microfluidizer at a pressure of 15,000 psi to obtain a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function.

[0077] Comparative Example 2

[0078] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function includes two layers, namely, a core layer and an outer layer from the inside to the outside;

[0079] The core layer is a zein-lac hydrophobic core encapsulating vitamin K2, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS);

[0080] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 20% of vitamin K2, 15% of zein, 15% of shellac, 23% of sodium alginate, 13% of CaCl2, and 14% of chitosan.

[0081] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0082] (1) 15% zein was dissolved in 100 mL of 70% ethanol aqueous solution by volume, and then stirred for 0.5 h to obtain a zein solution. 20% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified four times at a pressure of 800 bar using a high-pressure homogenizer. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 10 min to obtain a rotary emulsion. 15% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 3.5 using a hydrochloric acid solution. The mixture was stirred for 40 min to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule.

[0083] (2) 23% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, and the pH of the sodium alginate aqueous solution was adjusted to 3.5. The nano-scale zein-based vitamin K2 oil microcapsule core prepared in step (1) was added to the sodium alginate aqueous solution with a pH of 3.5, and stirred for 0.5 h to obtain an intermediate mixture. 13% CaCl2 and 14% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan aqueous solution. Subsequently, the intermediate mixture was squeezed into the stirred CaCl2-chitosan aqueous solution using a vibrating nozzle at a frequency of 1000 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0084] Comparative Example 3

[0085] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function includes two layers, namely, a core layer and an outer layer from the inside to the outside;

[0086] The core layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate (SA) and chitosan (CS);

[0087] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 20% vitamin K2, 15% pea protein, 15% low-ester pectin, 23% sodium alginate, 13% CaCl2, and 14% chitosan.

[0088] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0089] (1) 15% pea protein was dissolved in 100 mL of 70% by volume ethanol aqueous solution to obtain a pea protein solution, the pH of the pea protein solution was adjusted to 3.5, 20% vitamin K2 was added to the pea protein solution with a pH of 3.5, and the mixture was stirred for 0.5 h to obtain a mixed solution, 15% low-ester pectin was then added, and the mixture was homogenized three times using a microfluidizer at a pressure of 15,000 psi to obtain the inner core of a nano-sized pea protein-based vitamin K2 oil microcapsule;

[0090] (2) 23% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, and the pH of the sodium alginate aqueous solution was adjusted to 3.5. The nano-scale pea protein-based vitamin K2 oil microcapsule core prepared in step (1) was added to the sodium alginate aqueous solution with a pH of 3.5, and stirred for 0.5 h to obtain an intermediate mixture. 13% CaCl2 and 14% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan aqueous solution. Subsequently, the intermediate mixture was squeezed into the stirred CaCl2-chitosan aqueous solution using a vibrating nozzle at a frequency of 1000 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0091] Comparative Example 4

[0092] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function comprises a layer, i.e., a zein-lac hydrophobic core encapsulating vitamin K2;

[0093] Based on 100% of the total mass percentage of the raw materials, the raw material comprises the following raw material components: 50% of vitamin K2, 25% of zein, and 25% of shellac.

[0094] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0095] 25% zein was dissolved in 100 mL of 70% ethanol aqueous solution by volume, and then stirred for 0.5 h to obtain a zein solution. 50% vitamin K2 was added to the zein solution and stirred for 0.5 h to obtain a mixed solution. 30 mL of deionized water was then added to the mixed solution, and the mixture was emulsified four times at a pressure of 800 bar using a high-pressure homogenizer. The mixture was then subjected to reduced-pressure rotary evaporation at 70°C for 10 min to obtain a rotary emulsion. 25% shellac was dissolved in 50 mL of water to obtain a shellac aqueous solution. The rotary emulsion was then added to the shellac aqueous solution, and the pH of the system was adjusted to 3.5 using a hydrochloric acid solution. The mixture was stirred for 40 min to obtain a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function.

[0096] Comparative Example 5

[0097] The vitamin K2 complex microcapsule system with gastric protection and intestinal sustained-release function includes a layer of pea protein-pectin electrostatic complex encapsulating vitamin K2;

[0098] Based on 100% of the total mass percentage of the raw materials, the raw material components include: 50% of vitamin K2, 25% of pea protein, and 25% of low-ester pectin.

[0099] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0100] 25% pea protein was dissolved in 100 mL of water to obtain a pea protein aqueous solution, the pH of the pea protein aqueous solution was adjusted to 3.5, 50% vitamin K2 was added to 100 mL of the pea protein aqueous solution with a pH of 3.5 and stirred evenly, and then 25% low-ester pectin was added. Subsequently, a microfluidizer was used to homogenize three times at a pressure of 15,000 psi to obtain a vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function.

[0101] Comparative Example 6

[0102] The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function includes a layer, i.e., a double-network gel of sodium alginate (SA) and chitosan (CS) encapsulating vitamin K2;

[0103] Based on 100% of the total weight percentage of the raw materials, the raw material components include: 35% of vitamin K2, 35% of sodium alginate, 15% of CaCl2, and 15% of chitosan.

[0104] The preparation method of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function comprises the following steps:

[0105] 35% sodium alginate was dissolved in 100 mL of water to obtain a sodium alginate aqueous solution, the pH of the sodium alginate aqueous solution was adjusted to 3.5, 35% vitamin K2 was added to 100 mL of the sodium alginate aqueous solution with a pH of 3.5, and stirred for 0.5 h to obtain an intermediate mixture, 15% CaCl2 and 15% chitosan were dissolved in 50 mL of water and stirred uniformly to obtain a CaCl2-chitosan solution, and then the intermediate mixture was squeezed into the stirring CaCl2-chitosan solution using a vibrating nozzle at a frequency of 1000 Hz to obtain a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

[0106] Test Example 1: Encapsulation efficiency test of vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function

[0107] The embedding rate of vitamin K2 in the vitamin K2 complex microcapsule system with gastric protection and intestinal sustained release function prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was detected by solvent extraction method. The calculation formula of the embedding rate was: (the content of vitamin K2 embedded in the microcapsule system / the total content of vitamin K2 in the microcapsule system) * 100%, and the total content of vitamin K2 in the microcapsule system = the content of vitamin K2 on the surface of the microcapsule system + the content of vitamin K2 embedded in the microcapsule system. The detection results are shown in Table 1.

[0108] Measurement of the content of vitamin K2 on the surface of the microcapsule system: an appropriate amount of microcapsule system was weighed on filter paper, the sample on the filter paper was washed by soaking with anhydrous ethanol, the filtrate was collected, and the content of vitamin K2 was detected by HPLC method.

[0109] Measurement of the content of vitamin K2 embedded in the microcapsule system: the microcapsule system washed by anhydrous ethanol was transferred to a stoppered conical flask, anhydrous ethanol was added, and after ultrasonic treatment and centrifugation, the supernatant was taken, and the content of vitamin K2 was detected by HPLC method.

[0110] Table 1: Detection results of the embedding rate of the vitamin K2 complex microcapsule system with gastric protection and intestinal sustained release function

[0111]

[0112]

[0113] As can be seen from the results in Table 1, the embedding rates of the vitamin K2 complex microcapsule system with gastric protection and intestinal sustained release function provided in Examples 1 to 4 are all above 99%, which are higher than those in Comparative Examples 1 to 6, and the embedding rate of Example 4 reaches 99.8%. The vitamin K2 complex microcapsule system with gastric protection and intestinal sustained release function provided in the application can provide better protection for vitamin K2, and improve the utilization rate and stability of vitamin K2.

[0114] Test Example 2: Measurement of particle size, PDI and Zeta potential of the vitamin K2 complex microcapsule system with gastric protection and intestinal sustained release function

[0115] An appropriate amount of the vitamin K2 complex microcapsule system with gastric protection and intestinal sustained release function prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was respectively prepared into a solution with a concentration of 0.1 mg / mL by using ethanol, and the particle size distribution, PDI and Zeta potential thereof were detected by using a Zetasizer Pro Malven electric potential particle size analyzer. The sample was repeatedly measured for 3 times, and the measurement results were shown as average values. The measurement results are shown in Table 2.

[0116] Table 2: Measurement results of particle size, PDI and Zeta potential

[0117] Particle size PDI Zeta potential Example 1 405.7 0.129 -13.47 Example 2 408.9 0.125 -13.56 Example 3 417.2 0.133 -13.20 Example 4 421.4 0.147 -12.80 Comparative Example 1 506.2 0.214 -12.52 Comparative Example 2 513.8 0.218 -12.45 Comparative Example 3 518.5 0.217 -12.58 Comparative Example 4 595.4 0.246 -11.50 Comparative Example 5 589.8 0.237 -12.02 Comparative Example 6 592.2 0.241 -11.80

[0118] PDI (polydispersity index) is an indicator for measuring the width of particle size distribution. The smaller the value, the narrower the particle size distribution, that is, the more uniform the particle size. As can be seen from the results in Table 2, the PDI value of the vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function provided by Examples 1 to 4 of the present invention is less than 0.2, indicating that the particle size distribution of the system is very uniform and has good stability and dispersibility. Zeta potential is an important indicator for measuring the surface charge of particles. It reflects the charge state and stability of the particles in solution. Nanoparticles with higher Zeta potential absolute values ​​are relatively more stable. The Zeta potential absolute values ​​of the vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function provided by Examples 1 to 4 of the present invention are greater than those of Comparative Examples 1 to 6, indicating that the particle size distribution of the system is more uniform, not easy to attract each other and agglomerate in large quantities, and has good stability and dispersibility.

[0119] Test Example 3: Stability Test

[0120] The gastroprotective and intestinal sustained-release vitamin K2 composite microcapsule systems prepared in Examples 1 to 4 and Comparative Examples 1 to 6 were evaluated for their stability after 90 days under different conditions. The evaluation was conducted based on appearance, odor, encapsulation efficiency, retention rate, and reconstitution properties.

[0121] The appearance and smell were tested by sensory evaluation.

[0122] The method for detecting the embedding efficiency is shown in Test Example 1.

[0123] Retention rate testing: The vitamin K2 content before embedding was determined, and this content was set as the initial vitamin K2 content, C1. After the gastroprotective and intestinal sustained-release vitamin K2 composite microcapsule system was stored under different conditions for 90 days, samples were taken and the total vitamin K2 content was determined. This was the vitamin K2 content, C2, in the gastroprotective and intestinal sustained-release vitamin K2 composite microcapsule system after storage. Vitamin K2 retention rate = C2 / C1 x 100%. Determination of total vitamin K2 content: The microcapsule system was transferred to a stoppered conical flask, anhydrous ethanol was added, and the supernatant was collected after sonication and centrifugation. The vitamin K2 content was determined by HPLC.

[0124] Solubility: Take 10g of sample, add it into 100mL of water at room temperature, stir with a glass rod for 5 minutes, and observe the appearance.

[0125] 1) The vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1-4 and Comparative Examples 1-6 were sealed in soda-lime glass bottles and subjected to stability testing at a temperature of 37°C and a humidity of 75%. The test results are shown in Table 3.

[0126] Table 3 Stability test results under temperature 37°C and humidity 75%

[0127]

[0128]

[0129] From the results in Table 3, it can be seen that after 90 days, the appearance, smell, and solubility of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function prepared in Examples 1 to 4 did not change. The vitamin K2 encapsulation rate and retention rate decreased slightly but not significantly, and were still above 98%, and were better than those of Comparative Examples 1 to 6. This shows that the physical properties of the three-layer microcapsule system provided by the present invention remained stable within 90 days, had a good protection effect on vitamin K2, and maintained good solubility and dispersibility.

[0130] 2) The vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 were filled into oxygenated glass bottles and sealed, and stability tests were performed. The test results are shown in Table 4.

[0131] Table 4 Stability test results under oxygen conditions

[0132]

[0133]

[0134] From the results in Table 4, it can be seen that after 90 days, the appearance, smell, and solubility of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function prepared in Examples 1 to 4 did not change, and the vitamin K2 encapsulation rate and retention rate decreased slightly but not significantly, and were both better than those of Comparative Examples 1 to 6, indicating that the physical properties of the three-layer microcapsule system provided by the present invention remained stable within 90 days, had a good protection effect on vitamin K2, could prevent oxygen from damaging vitamin K2, and maintained good solubility and dispersibility.

[0135] 3) The vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 were filled into sealed glass bottles and irradiated at a light intensity of 4500 Lx for stability testing. The test results are shown in Table 5.

[0136] Table 5 Stability test results under 4500Lx light intensity conditions

[0137]

[0138]

[0139] From the results in Table 5, it can be seen that after 90 days, the appearance, smell, and solubility of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function prepared in Examples 1 to 4 did not change, and the vitamin K2 encapsulation rate and retention rate decreased slightly but not significantly, and were both better than those of Comparative Examples 1 to 6, indicating that the physical properties of the three-layer microcapsule system provided by the present invention remained stable within 90 days, had a good protection effect on vitamin K2, could prevent the damage of vitamin K2 to light, and maintained good solubility and dispersibility.

[0140] 4) The vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 were filled into sealed glass bottles and placed in a 60° C. thermostat for stability testing. The test results are shown in Table 6.

[0141] Table 6 Stability test results at 60℃

[0142]

[0143]

[0144] From the results in Table 6, it can be seen that after 90 days, the appearance, smell, and solubility of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function prepared in Examples 1 to 4 did not change, and the vitamin K2 encapsulation rate and retention rate decreased slightly but not significantly, and were both better than those of Comparative Examples 1 to 6, indicating that the physical properties of the three-layer microcapsule system provided by the present invention remained stable within 90 days, had a good protection effect on vitamin K2, could avoid the damage of vitamin K2 to high temperature, and maintained good solubility and dispersibility.

[0145] Test Example 4: In vitro digestion simulation:

[0146] Weigh 0.5 g of each sample of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function prepared in Examples 1 to 4 and Comparative Examples 1 to 6, and add them to 10 mL of simulated gastric fluid or simulated intestinal fluid, respectively. The compositions of the simulated gastric fluid and the simulated intestinal fluid are shown in Table 7. 1 mg 1000 U / mg of pepsin was added to the simulated gastric fluid and the pH was adjusted to 2.1 using hydrochloric acid. 1 mg 1000 U / mg of complex enzyme (trypsin and amylase, the mass ratio of trypsin and amylase was 1:1) was added to the simulated intestinal fluid and the pH was adjusted to 7.0. The retention rate of vitamin K2 was then measured at 15 min, 60 min, and 120 min, respectively. The results of the retention rate of vitamin K2 in simulated gastric fluid are shown in Table 7. Figure 1 The results of the retention rate of vitamin K2 in simulated intestinal fluid are shown in Figure 2 shown.

[0147] Table 7 Composition of simulated gastric fluid and simulated intestinal fluid

[0148] Components Simulated gastric fluid Simulated intestinal fluid 0.5mol / L KCl / mL 6.9 6.8 <![CDATA[0.5mol / L KH2PO4 / mL]]> 0.9 0.8 <![CDATA[1mol / L NaHCO3 / mL]]> 12.5 42.5 2mol / L NaCl / mL 11.8 9.6 0.15 mol / L MgCl2 / mL 0.4 1.1 <![CDATA[0.5mol / L(NH4)2CO3 / mL]]> 0.5 /

[0149] from Figure 1 、 Figure 2 As can be seen from the results, the retention rates of vitamin K2 in the vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1 to 4 in simulated gastric fluid were higher than those in Comparative Examples 1 to 6. The high retention rates of vitamin K2 in simulated gastric fluid indicate that the activity can be retained for as long as possible in the human stomach. However, the retention rates of vitamin K2 in the vitamin K2 composite microcapsule systems with gastric protection and intestinal sustained-release functions prepared in Examples 1 to 4 in simulated intestinal fluid were lower than those in Comparative Examples 1 to 6. The low retention rates of vitamin K2 in simulated intestinal fluid indicate that absorption in the intestine is promoted. Vitamin K2 is a fat-soluble vitamin and is easily destroyed by gastric acid and digestive enzymes in the stomach. The three-layer microcapsule system for encapsulating vitamin K2 provided by the present invention can be tightly bound in a gastric acid environment, reduce the release of active ingredients in gastric fluid, and then release them in the intestine, thereby improving the effect. The three-layer microcapsule system of vitamin K2 utilizes a layered structure to effectively protect vitamin K2 in the gastric environment and keep its structure intact for a long time, thereby achieving high retention of vitamin K2 in the stomach and high release in the intestine.

[0150] The above description is only a specific embodiment of the present invention, not all embodiments. Any equivalent transformation of the technical solution of the present invention made by ordinary technicians in this field after reading the specification of the present invention is covered by the claims of the present invention.

Claims

1. A microcapsule system, characterized in that: It consists of three layers, from the inside to the outside: the core layer, the middle layer and the outer layer; The core layer is a zein-lac hydrophobic core, the middle layer is a pea protein-pectin electrostatic complex, and the outer layer is a double network gel of sodium alginate and chitosan.

2. Use of the microcapsule system according to claim 1 as a vitamin K2 embedding system.

3. A vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function, characterized in that: It consists of three layers, from the inside to the outside: the core layer, the middle layer and the outer layer; The core layer is a zein-lac hydrophobic core that encapsulates vitamin K2; the middle layer is a pea protein-pectin electrostatic complex; and the outer layer is a double-network gel of sodium alginate and chitosan.

4. The vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function according to claim 3, characterized in that: Based on 100% of the total mass percentage of raw materials, the raw material components include: 5% to 20% of vitamin K2, 5% to 20% of zein, 5% to 20% of shellac, 5% to 15% of pea protein, 5% to 20% of low-ester pectin, 10% to 30% of sodium alginate, 5% to 15% of calcium chloride, and 5% to 15% of chitosan.

5. The method for preparing the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained release function according to any one of claims 3 to 4, characterized in that: The following steps are involved: (1) Zein is fully dissolved in a solvent to obtain a zein solution, vitamin K2 is added to the zein solution and stirred to obtain a mixed solution, water is then added to the mixed solution, emulsified using a high-pressure homogenizer, and then rotary evaporated to obtain a rotary evaporated emulsion, shellac is dissolved in water to obtain a shellac aqueous solution, and then the rotary evaporated emulsion is added to the shellac aqueous solution and the pH of the system is adjusted to 2.5-3.5, and stirring is continued for a period of time to obtain the inner core of the nano-zein-based vitamin K2 oil microcapsule; (2) dissolving pea protein in water to obtain a pea protein aqueous solution, adjusting the pH of the pea protein aqueous solution to 3-4.5, adding the nano-scale zein-based vitamin K2 oil microcapsule core prepared in step (1) to the pea protein aqueous solution with a pH of 3-4.5, stirring evenly, adding low-ester pectin, and then homogenizing using a microfluidizer to obtain vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure; (3) Sodium alginate is dissolved in water to obtain a sodium alginate aqueous solution, the pH of the sodium alginate aqueous solution is adjusted to 3-4.5, the vitamin K2 microcapsules with a micro-nanoscale double-layer composite structure prepared in step (2) are added to the sodium alginate aqueous solution with a pH of 3-4.5 and stirred to obtain an intermediate mixed solution, calcium chloride and chitosan are dissolved in water and stirred to obtain a calcium chloride chitosan aqueous solution, and then the intermediate mixed solution is squeezed into the stirring calcium chloride chitosan aqueous solution using a vibrating nozzle to obtain vitamin K2 oil particles with a uniform three-layer protective structure, i.e., a vitamin K2 composite microcapsule system with gastric protection-intestinal sustained-release function.

6. The preparation method according to claim 5, characterized in that The solvent in step (1) is selected from an ethanol aqueous solution with a volume percentage of 60% to 80%; The emulsification pressure in step (1) is 600 to 1000 bar, and the number of emulsifications is 1 to 5 times; The rotary evaporation in step (1) is a reduced pressure rotary evaporation at 65-75° C., and the rotary evaporation time is 5-15 minutes; The stirring time in step (1) is 30 to 50 minutes.

7. The preparation method according to claim 5, characterized in that The homogenization pressure in step (2) is 10,000 to 15,000 psi, and the number of homogenizations is 1 to 5 times.

8. The preparation method according to claim 5, characterized in that The frequency of the vibrating nozzle in step (3) is 800 to 1000 Hz.

9. Use of the vitamin K2 composite microcapsule system with gastric protection and intestinal sustained-release function according to any one of claims 3 to 4 in the preparation of drugs for maintaining bone health, preventing cardiovascular diseases, protecting nerves, and improving metabolism.

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