A preparation method for improving absorption of active ingredients based on microencapsulation of plant proteins

Abstract

The present application belongs to the field of food and nutrition technology, and specifically relates to a preparation method for improving the absorption rate of active ingredients based on plant protein microencapsulation. The present application aims to solve the technical problems of low encapsulation rate, limited loading capacity and low absorption rate in the prior art. In the present application, plant proteins are subjected to enzymatic pretreatment to enhance their functional properties and reactivity, and then the plant proteins after enzymatic hydrolysis are grafted with polysaccharides by Maillard reaction to obtain plant protein-polysaccharide grafts, which have excellent emulsifying and film-forming properties. In the present application, the grafts are mixed with an oil phase containing fat-soluble active ingredients to form an emulsion, an anionic polysaccharide solution is added to form a second dense coating layer, and a polyphenol and metal ion solution is added to form a strong metal-polyphenol network as the outermost coating, thereby effectively protecting the fat-soluble active ingredients and improving their release and absorption in the intestinal tract. Finally, the plant protein microencapsulated active ingredients are obtained by spray drying and solidification.

Description

Technical Field

[0001] This invention belongs to the field of food and nutrition technology, and specifically relates to a preparation method based on the improvement of the absorption rate of active ingredients through microencapsulation of plant proteins. Background Technology

[0002] Many functional nutrients, such as vitamins, fatty acids, and plant extracts, are difficult to add directly to foods or supplements due to their poor water solubility, low stability in the gastrointestinal environment, and limited bioavailability. Microencapsulation technology is an effective means to improve the stability and absorption rate of such active substances. Fat-soluble active ingredients, such as vitamins and curcumin, are crucial to human health, but their low water solubility and low bioavailability severely limit their application effects. Microencapsulation technology is an effective strategy to protect these sensitive ingredients and improve their stability and bioavailability. Among them, microcapsules using plant proteins such as pea protein and soy protein as wall materials have attracted much attention due to their natural, nutritious, and sustainable advantages. However, existing plant protein-based microcapsule technologies still face many challenges:

[0003] 1. Low encapsulation efficiency and limited loading: Natural plant proteins have limited emulsifying ability and poor emulsion stability under high oil phase loading, resulting in low encapsulation efficiency and difficulty in increasing the loading of active ingredients.

[0004] 2. Insufficient gastric juice protection: Plant proteins are prone to denaturation and aggregation in the acidic gastric environment, leading to the disintegration of the microcapsule structure. This causes the active ingredients to be prematurely exposed and degraded, preventing them from effectively reaching the intestines.

[0005] 3. Incomplete intestinal release: Even if the active ingredients successfully reach the intestines, some dense protein walls are difficult for trypsin to effectively break down, resulting in slow and incomplete release of the active ingredients and a significantly reduced absorption rate.

[0006] Therefore, this invention proposes an innovative method for preparing multilayer microcapsules based on plant proteins, aiming to fully leverage the synergistic advantages of each modification method and fundamentally solve the technical problems related to encapsulation efficiency and controlled release. Summary of the Invention

[0007] The technical problem this invention aims to solve is to provide a preparation method based on plant protein microencapsulation to improve the absorption rate of active ingredients, overcoming the shortcomings of existing technologies such as low encapsulation efficiency, limited carrier oil content, poor protective effect in gastric juice, and insufficient intestinal release. Through the method of this invention, the prepared microcapsules can maintain the stability of the core active substance in the stomach without release while rapidly releasing it after entering the intestine, thereby significantly improving the bioavailability and functional effects of the active ingredients.

[0008] A preparation method for improving the absorption rate of active ingredients based on plant protein microencapsulation, the technical solution of which is as follows:

[0009] S1: Dissolve plant protein in deionized water and stir until completely dissolved. Add flavor protease at 2% of the plant protein mass and perform enzymatic hydrolysis in a 50°C water bath for 60 minutes. Then heat the solution to 95°C and maintain it for 10 minutes. Add polysaccharide to carry out Maillard reaction. After stirring and dissolving, adjust the pH of the system to 7.5 and carry out the reaction at a constant temperature. Then cool the reaction solution to room temperature to prepare the graft solution.

[0010] Furthermore, plant protein, such as pea protein isolate, chickpea protein powder, or soy protein isolate, is prepared with deionized water to form a solution with a mass concentration of 7% to 9%.

[0011] Furthermore, polysaccharides, such as sodium alginate, carboxymethyl cellulose, or carrageenan, are used in an amount of 10% relative to the plant protein content.

[0012] Furthermore, the reaction is carried out at a constant temperature, specifically by placing the solution in a constant temperature water bath at 65–75°C for 2–4 hours.

[0013] S2: Mix the oil phase with the graft solution prepared in step S2 in a certain proportion, and then emulsify it for 2 minutes at 12000 rpm using a high-speed shear mill to form a crude emulsion. Then, homogenize it three times at 60 MPa using a high-pressure homogenizer, with the high-pressure valve temperature controlled at 30℃, to obtain a uniform and fine emulsion.

[0014] Furthermore, the oil phase consists of a carrier oil and a fat-soluble active ingredient, wherein the carrier oil is selected from corn oil, MCT oil or algal oil; the fat-soluble active ingredient is selected from vitamin D3 or curcumin, and is mixed with the carrier oil to prepare a mass concentration of 0.8% to 1.2%.

[0015] Furthermore, specifically, the mass ratio of the oil phase to the graft solution is 1:4 to 1:6.

[0016] S3: Transfer the uniform and delicate emulsion prepared in step S2 to a constant temperature stirring tank at 4℃, add polysaccharide solution dropwise at a rate of 1mL / min, adjust the pH of the system with acetic acid, and stir at 4℃ for 30 minutes to prepare a secondary coated emulsion.

[0017] Further, a polysaccharide solution was added dropwise at a rate of 0.8%–1.2% w / v and a dropping rate of 1 mL / min.

[0018] Furthermore, the pH of the system is specifically 3.8–4.2.

[0019] S4: Take half the volume of the polyphenol solution prepared in step S3 into the secondary coating emulsion, mix it with the emulsion, adjust the pH of the system to 3.5 with acetic acid, and then add the metal ion solution. The volume ratio of polyphenol solution to metal ion solution is 1:1. Use a pipette pump to drop the metal ions into the emulsion at a rate of 1 mL / min. After the addition is complete, continue stirring for 15 minutes to prepare the microcapsule solution.

[0020] Furthermore, the polyphenol solution and the metal ion solution are selected, wherein the polyphenol solution is selected from tannic acid or gallic acid, and its content is 0.4% to 0.6% w / v; the metal ion solution is selected from ferric citrate solution or ZnSO4 solution, and its content is 0.4% to 0.6% w / v.

[0021] S5: The microcapsule solution prepared in step S4 is fed into a spray drying tower using a feed pump, and the inlet air temperature is set to 160℃, the outlet air temperature to 75℃, and the feed rate to 5mL / min; the obtained microcapsule powder is collected and placed in a vacuum dryer to cool to room temperature, and finally the active ingredient of plant protein microencapsulation is obtained.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. This invention improves the functional properties of plant protein as a wall material through enzymatic hydrolysis and Maillard dual modification, which greatly enhances its ability to encapsulate oily active substances. The double-layered capsule wall formed by electrostatic composite coating improves the stability of microcapsules in gastric juice and reduces the leakage of active substances under acidic conditions.

[0024] 2. This invention introduces a polyphenol-metal network to make the capsule wall cross-linked and dense, providing extra protection during storage and digestion, exhibiting excellent antioxidant and gastric acid resistance properties, and ensuring the activity of the active ingredients until they reach the small intestine.

[0025] 3. This invention introduces a second type of anionic polysaccharide to deposit a second wall material around the oil droplet using electrostatic interactions, thereby adding a dense protective shell to the initial graft membrane, effectively improving the thickness and strength of the capsule wall. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of an active ingredient based on the microencapsulation of plant proteins to improve absorption rate, according to the present invention.

[0027] Figure 2 The graph shows a comparison of the encapsulation efficiency test results of Examples 1-3 and Comparative Examples 1-4.

[0028] Figure 3 This is a comparison chart of the results of in vitro release experiments. Detailed Implementation

[0029] The following embodiments further explain and illustrate the technical solutions of the present invention. It is particularly noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention. (See attached...) Figure 1 The diagram shows a preparation process for improving the absorption rate of active ingredients based on the microencapsulation of plant proteins. The preparation steps are as follows:

[0030] 1. Plant proteolytic modification

[0031] Plant protein was selected as the wall material substrate and first underwent enzymatic pretreatment. Flavorful proteases were used to hydrolyze the plant protein, and the temperature and time were controlled to obtain a protein hydrolysate with a certain degree of hydrolysis. On the one hand, enzymatic hydrolysis can improve the solubility and surface activity of plant protein, increase the exposure of functional groups, and provide more reaction sites for subsequent Maillard grafting; on the other hand, it can reduce the molecular weight of plant protein, which helps to improve its emulsifying properties and microcapsule membrane formation properties.

[0032] 2. Maillard reaction grafting

[0033] Plant proteins, after enzymatic hydrolysis, are covalently bound to polysaccharides via a Maillard reaction. The polysaccharides are selected from food-grade polysaccharides with active carboxyl / reducing ends, such as sodium alginate, carboxymethyl cellulose, or carrageenan. By controlling the protein-to-polysaccharide ratio, reaction pH, and heating conditions, Maillard condensation occurs between the ε-amino groups of the protein molecules and the carbonyl groups of the polysaccharides, generating a protein-polysaccharide grafted covalent complex. Compared to a simple physical mixture of protein and polysaccharides, the Maillard grafted product exhibits superior stability and functionality at the solution interface due to the covalent bond between the protein and polysaccharide: the protein portion can be directionally adsorbed at the oil-water interface, reducing interfacial tension, while the polysaccharide portion extends to the periphery of the interface, forming a hydration layer and network structure, significantly improving emulsion stability. Therefore, the grafted product can be used as a high-performance first-layer wall material, providing a basic encapsulation structure for microcapsules.

[0034] 3. Emulsification and initial formation of microcapsules

[0035] The grafted product was used as an emulsifier and mixed with the desired fat-soluble active ingredient and carrier oil for emulsification. A stable water-in-oil emulsion was prepared by high-speed shear pre-emulsification and high-pressure homogenization to refine the droplets. At this stage, the active substance in the oil phase is dispersed into fine oil droplets, which are initially coated by the adsorption film formed by the grafted product. Compared to unmodified proteins, the film formed by the grafted product at the interface is more stable and dense, significantly improving the oil droplet encapsulation efficiency and reducing droplet aggregation or breakage during emulsion storage.

[0036] 4. Electrostatic recombination secondary coating

[0037] A second anionic polysaccharide is introduced into the emulsion system to deposit a second wall material around the oil droplets using electrostatic interactions. The pH of the emulsion is adjusted to be slightly lower than the isoelectric point of the protein in the graft, at which point the protein carries a positive charge, while the selected anionic polysaccharide remains negatively charged. The anionic polysaccharide solution is slowly added to the emulsion. The oppositely charged protein and polysaccharide are electrostatically attracted, causing the polysaccharide to accumulate and precipitate on the oil droplet surface, forming a composite aggregated layer. This layer acts like an additional dense protective shell on top of the initial graft membrane, effectively increasing the thickness and strength of the capsule wall. The electrostatic composite coating process should be carried out at low temperatures to avoid excessively rapid oil droplet movement affecting the coating uniformity. After a certain curing time, a composite capsule wall composed of the graft and the anionic polysaccharide forms on the surface of the oil droplets.

[0038] 5. Metal-polyphenol network crosslinking

[0039] To further enhance the stability of the capsule wall under harsh environments such as gastric acid, a metal-polyphenol network layer was introduced as the outermost wall material on the surface of the microcapsules. Polyphenols and polyvalent metal ion solutions were then added sequentially to the suspension system obtained in step 4. The polyphenols included tannic acid and gallic acid, and the metal ions selected were Fe, which can coordinate with the polyphenols. 3+ or Zn 2+ The process involves first adding a certain amount of polyphenols to allow them to adsorb or penetrate the already formed capsule wall. Then, a metal salt solution is slowly introduced, causing multi-point coordination with the polyphenols and constructing a cross-linked network composed of metal-polyphenol complexes on the capsule wall surface in situ. The deposition of the metal-polyphenol network can be completed rapidly at room temperature without the need for organic solvents, making it a green and environmentally friendly cross-linking method. This network layer acts like an "armor" for the microcapsule, significantly improving the mechanical strength and resistance to chemical stress of the capsule wall. Especially under strongly acidic conditions, the stable presence of the metal-polyphenol bonds prevents rapid capsule wall disintegration, thus protecting the contents from premature release. In the neutral to slightly alkaline intestinal environment, the complex bonds gradually dissociate or swell, releasing the active ingredients.

[0040] 6. Drying and finished product preparation

[0041] The multi-layered encapsulated emulsion is then dried and solidified using spray drying to transform the liquid emulsion into solid microcapsule powder. By controlling the appropriate inlet air temperature and drying time, moisture is rapidly removed while maintaining the integrity of the capsule wall structure, resulting in a microcapsule product with good flowability.

[0042] Example 1

[0043] Table 1 Raw Material Information Table

[0044]

[0045] A preparation method for improving the absorption rate of active ingredients based on plant protein microencapsulation, comprising the following steps:

[0046] S1: Pea protein isolate was dissolved in deionized water to prepare an 8% (w / w) solution, which was then stirred until completely dissolved. Flavor protease at 2% (w / w) of the plant protein mass was added, and the mixture was enzymatically hydrolyzed in a 50°C water bath for 60 minutes. After hydrolysis, the solution was rapidly heated to 95°C and maintained for 10 minutes to inactivate the enzyme. Then, sodium alginate at 10% (w / w) of the plant protein mass was added to initiate a Maillard reaction. After stirring and dissolving, the pH was adjusted to 7.5, and the solution was placed in a 70°C constant temperature water bath for 3 hours. After 3 hours, the reaction was stopped, and the reaction solution was rapidly cooled to room temperature to prepare the pea protein-sodium alginate graft solution.

[0047] S2: Corn oil was selected as the carrier oil and used as the matrix to form an oil phase with the fat-soluble active ingredient, and the mass concentration was 1.0%. The fat-soluble active ingredient was vitamin D3. The oil phase was mixed with the graft solution prepared in step S2, and the mass ratio of the oil phase to the graft solution was controlled at 1:5. The mixture was then emulsified at 12,000 rpm for 2 minutes using a high-speed shear mill to form a crude emulsion. The emulsion was then homogenized three times at 60 MPa using a high-pressure homogenizer, with the high-pressure valve temperature controlled at 30°C, to obtain a uniform and fine emulsion.

[0048] S3: Transfer the homogeneous and fine emulsion prepared in step S2 to a 4°C constant-temperature stirring jar. Add 1% (w / v) of a polysaccharide solution, preferably sodium alginate aqueous solution, at a dropping rate of 1 mL / min. Adjust the pH of the system to 4.0 with acetic acid to avoid sudden changes in local concentration that could cause emulsion instability. Stir at 4°C for 30 minutes to allow the cationic pea protein graft to fully recombine with the anionic alginate ions, forming a second dense coating layer, thus preparing a secondary coated emulsion.

[0049] S4: Take half the volume of polyphenol solution from the secondary encapsulation emulsion prepared in step S3. The polyphenol solution should be a 0.5% (w / v) tannic acid solution. Add this solution to the secondary encapsulation emulsion prepared in step S3, and adjust the pH of the system to 3.5 with acetic acid. Then add a metal ion solution, specifically a 0.5% ferric citrate solution. Use a pipette pump to add the ferric citrate solution dropwise into the emulsion at a rate of 1 mL / min. The ferric citrate solution will undergo a coordination complexation reaction with the tannic acid in the system. After the addition is complete, continue stirring for 15 minutes to prepare the microcapsule solution.

[0050] S5: The microcapsule solution prepared in step S4 is fed into a spray drying tower using a feed pump, and the inlet air temperature is set to 160℃, the outlet air temperature to 75℃, and the feed rate to 5mL / min; the obtained microcapsule powder is collected and placed in a vacuum dryer to cool to room temperature, and finally the active ingredient of plant protein microencapsulation is obtained.

[0051] Example 2

[0052] The preparation method is the same as in Example 1, but with the following differences:

[0053] In step S1, chickpea protein powder was selected as the plant protein, and a 7% (w / w) solution was prepared; sodium alginate was replaced with carboxymethyl cellulose, the constant temperature water bath temperature was 65℃, and the reaction time was 4 hours.

[0054] In step S2, MCT oil is selected as the carrier oil, curcumin is selected as the fat-soluble active ingredient, the mass concentration is 0.8%, and the mass ratio of oil phase to graft solution is controlled at 1:4.

[0055] In step S3, the polysaccharide solution is selected as a 0.8% (w / v) carboxymethyl cellulose solution, and the pH of the system is adjusted to 4.2 with acetic acid;

[0056] In step S4, the polyphenol solution is selected as a 0.4% (w / v) gallic acid solution, and the metal ion solution is selected as a 0.4% ZnSO4 solution.

[0057] Example 3

[0058] The preparation method is the same as in Example 1, but with the following differences:

[0059] In step S1, the plant protein selected is soy protein isolate, and a 9% (w / w) solution is prepared; sodium alginate is replaced with carrageenan, the constant temperature water bath temperature is 75℃, and the reaction time is 2 hours.

[0060] In step S2, algal oil is selected as the carrier oil, which forms an oil phase with the fat-soluble active ingredient and is prepared with a mass concentration of 1.2%. The mass ratio of the oil phase to the graft solution is controlled at 1:6.

[0061] In step S3, a 1.2% (w / v) carrageenan solution was selected as the polysaccharide solution, and the pH of the system was adjusted to 3.8 with acetic acid.

[0062] In step S4, the polyphenol solution is selected as a 0.6% (w / v) gallic acid solution, and the metal ion solution is selected as a 0.6% ZnSO4 solution.

[0063] Comparative Example 1

[0064] The preparation method of Example 1 was followed, but without enzymatic pretreatment, the plant protein was directly subjected to Maillard modification. All other steps were the same.

[0065] Comparative Example 2

[0066] The preparation method of Example 1 was followed, but without Maillard modification; the plant protein was directly mixed with the oil phase. All other steps were the same.

[0067] Comparative Example 3

[0068] Following the preparation method of Example 1, but without performing a second coating, polyphenols and metal ion solutions were directly added to the homogeneous and fine emulsion obtained in step S2 of Example 1. All other steps were the same.

[0069] Comparative Example 4

[0070] The preparation method of Example 1 was followed, but the outer network cross-linking operation was omitted; that is, no polyphenols and metal ion solutions were added, and spray drying was performed directly. All other steps were the same.

[0071] The active ingredients based on plant protein microencapsulation prepared in combined Examples 1-3 and Comparative Examples 1-4 were subjected to encapsulation efficiency testing and in vitro release experiments.

[0072] Encapsulation efficiency test: The plant protein microcapsules prepared in Examples 1-3 and Comparative Examples 1-4 were dissolved and centrifuged to separate the precipitate. After washing and drying, the cell walls were broken. The concentration of the active ingredient was determined by high performance liquid chromatography. The encapsulation efficiency was calculated according to the formula: encapsulation efficiency = (mass of encapsulated active ingredient / total amount of active ingredient added) × 100%.

[0073] In vitro release experiment:

[0074] (1) Model building

[0075] Simulated gastric juice: a hydrochloric acid solution with a pH of 2.0 containing 0.32% (w / v) pepsin (from pig stomach).

[0076] Simulated intestinal fluid: phosphate buffer at pH 7.4 containing 1% (w / v) pancreatic enzymes (from porcine pancreas).

[0077] Experimental conditions: All release experiments were conducted in a 37°C constant temperature water bath with a stirring speed of 100 rpm to simulate gastrointestinal peristalsis.

[0078] (2) Experimental grouping

[0079] Seven experimental groups were set up, with six parallel samples prepared in each group. Gastric and intestinal fluid release experiments were conducted on every three samples. The first group contained the final product prepared in Example 1, the second group in Example 2, the third group in Example 3, the fourth group in Comparative Example 1, the fifth group in Comparative Example 2, the sixth group in Comparative Example 3, and the seventh group in Comparative Example 4. The active ingredient content of each final product was then determined to standardize the calculation of the release rate. The method for determining the active ingredient content was as follows: 10 mg of the final product was completely dissolved in methanol, and the concentration of the active ingredient was measured by HPLC.

[0080] (3) Experimental steps

[0081] Active ingredient content: Take 10 mg of each final product sample, dissolve it in 10 mL of appropriate solvent, vortex mix and sonicate for 10 minutes to ensure complete dissolution;

[0082] Release experiment: The final product equivalent to 10 mg of active ingredient was placed in a dialysis bag, which was then immersed in 500 mL of gastric fluid. The mixture was stirred at 37 °C and 100 rpm. At predetermined time points, 2 mL of release medium was sampled from gastric fluid at 0.5 h, 1 h, and 2 h to measure the concentration; 2 mL of release medium was sampled from intestinal fluid at 0.5 h, 1 h, 2 h, and 3 h. An equal volume of fresh medium was added to maintain a constant volume. The samples were filtered through a 0.22 μm filter membrane, and the concentration of the active ingredient was measured by HPLC.

[0083] Release rate calculation: Cumulative release rate (%) = (Cumulative release amount / Total active ingredient amount) × 100% (Cumulative release amount is calculated by multiplying the concentration at each time point by the volume and summing the results)

[0084] The specific test comparison results are shown in Table 2. Figure 2 , Figure 3 As shown:

[0085] Table 2. Comparison of overall performance between Examples 1-3 and Comparative Examples 1-4

[0086]

[0087] The comparison results show that in Comparative Example 1, the lack of enzymatic pretreatment resulted in insufficient expansion of the plant protein's molecular structure, reduced Maillard reaction efficiency, insufficient emulsification of the wall material, and decreased encapsulation effect. Furthermore, the absence of enzymatic hydrolysis led to incomplete Maillard graft structure, insufficient capsule wall density, and easy permeation by gastric acid, resulting in increased leakage of active ingredients. In Comparative Example 2, the lack of Maillard modification resulted in the plant protein lacking the assistance of polysaccharide chains, significantly reducing the stability and encapsulation capacity of the wall material. The emulsion was prone to rupture during homogenization, and the capsule wall relied solely on natural protein, exhibiting poor acid resistance and mechanical strength, leading to rapid release of active ingredients in gastric juice. In Comparative Example 3, the lack of a secondary coating layer resulted in a thin capsule wall, leading to the loss of some active ingredients during emulsification. The microcapsules lacking an electrostatic coating layer exhibited decreased tolerance in gastric juice, and the single-layer capsule wall could not effectively resist gastric acid, resulting in easy leakage of active ingredients in the stomach. In Comparative Example 4, the lack of polyphenol-metal network cross-linking resulted in an insufficiently dense capsule wall, increasing gastric acid permeability.

[0088] In summary, the enzymatic hydrolysis combined with Maillard-modified plant protein grafts provides a stable and efficient first interfacial membrane, significantly improving initial encapsulation efficiency; the electrostatic composite second layer significantly enhances the integrity of the capsule wall under gastric acid conditions, reducing the loss of core substances; and the metal-polyphenol network outer layer further strengthens the mechanical and chemical stability of the capsule wall, enabling the microcapsules to exhibit excellent stability during storage and in the gastric environment. The microcapsules prepared by the method of this invention have significant advantages and superiority in protecting easily degradable active ingredients, controlling their release, and improving bioavailability.

Claims

1. A preparation method for improving the absorption rate of active ingredients based on plant protein microencapsulation, characterized in that, S1: Dissolve pea protein isolate, chickpea protein powder, or soy protein isolate in deionized water to prepare a solution with a mass concentration of 7% to 9%. Stir until completely dissolved, add flavor protease at 2% of the plant protein mass, and perform enzymatic hydrolysis in a 50°C water bath for 60 minutes. Then heat the solution to 95°C and maintain it for 10 minutes. Then add sodium alginate, carboxymethyl cellulose, or carrageenan at 10% of the plant protein mass to carry out the Maillard reaction. After stirring and dissolving, adjust the pH of the system to 7.5 and carry out the isothermal reaction. Then cool the reaction solution to room temperature to prepare the graft solution. S2: The oil phase composed of corn oil, MCT oil or algal oil and vitamin D3 or curcumin is mixed with the graft solution prepared in step S1 at a mass ratio of 1:4 to 1:6, wherein the mass concentration of the fat-soluble active ingredient in the oil phase is 0.8% to 1.2%; then emulsified at 12000 rpm for 2 minutes using a high-speed shear mill to form a crude emulsion, and then homogenized three times at 60 MPa using a high-pressure homogenizer, with the high-pressure valve temperature controlled at 30℃, to obtain a uniform and fine emulsion; S3: Transfer the uniform and delicate emulsion prepared in step S2 to a constant temperature stirring tank at 4℃, add polysaccharide solution dropwise at a rate of 0.8% to 1.2% w / v and a dropping rate of 1 mL / min, adjust the pH of the system with acetic acid, stir at 4℃ for 30 minutes to prepare a secondary coated emulsion. S4: Take half the volume of the secondary coating emulsion prepared in step S3, add 0.4%–0.6% w / v tannic acid or gallic acid solution, mix it with the emulsion, adjust the pH of the system to 3.5 with acetic acid, then add 0.4%–0.6% w / v ferric citrate solution or ZnSO4 solution, with a polyphenol solution to metal ion solution volume ratio of 1:

1. Use a pipette pump to add metal ions dropwise into the emulsion at a rate of 1 mL / min. After the addition is complete, continue stirring for 15 minutes to prepare the microcapsule solution. S5: The microcapsule solution prepared in step S4 is fed into the spray drying tower using a feed pump, and the inlet air temperature is set to 160℃, the outlet air temperature to 75℃, and the feed rate to 5mL / min; the obtained microcapsule powder is collected and placed in a vacuum dryer to cool to room temperature, and finally the active ingredient of plant protein microencapsulation is obtained. The preparation method involves pretreating plant proteins with enzymatic hydrolysis to enhance their functional properties and reactivity, followed by a Maillard reaction to graft the hydrolyzed plant proteins with polysaccharides to obtain a plant protein-polysaccharide graft. The graft is then mixed with an oil phase containing lipophilic active ingredients to form an emulsion, and an anionic polysaccharide solution is added to form a second dense coating layer. Finally, a robust metal-polyphenol network is formed as the outermost coating layer by adding polyphenol and metal ion solutions.

2. The preparation method for improving the absorption rate of active ingredients based on plant protein microencapsulation as described in claim 1, characterized in that, The isothermal reaction described in step S1 specifically involves placing the solution in a constant temperature water bath at 65–75°C for 2–4 hours.

3. The preparation method for improving the absorption rate of active ingredients based on plant protein microencapsulation as described in claim 1, characterized in that, The pH of the system described in step S3 is specifically 3.8 to 4.2.

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