Preparation method and application of targeted colon delivery polyunsaturated fatty acid grease microcapsule

Abstract

The invention belongs to the field of food processing, and discloses a preparation method and application of a targeted colon delivery polyunsaturated fatty acid grease microcapsule. 11S globulin in soybeans and Arabic gum are used as wall materials of the microcapsule, complex coacervation of the 11S globulin in the soybeans and the Arabic gum is induced under a certain pH condition, so that oil drops are wetted by a coacervate, a core-shell structure is formed, a coacervate phase is further stabilized through glucan to inhibit coalescence, and on the basis, the microcapsule is prepared. And tannic acid, polysaccharide and protein can form hydrogen bonds and generate hydrophobic interaction to further crosslink the condensed phase to obtain the microcapsule capable of resisting digestion of the stomach and the small intestine, so that colon delivery of polyunsaturated fatty acid is realized.

Description

Technical Field

[0001] The invention belongs to the field of food processing, and in particular relates to a preparation method and application of colon-targeted polyunsaturated fatty acid oil microcapsules. Background Art

[0002] Functional oils rich in polyunsaturated fatty acids can be transformed by colonic microorganisms to produce metabolites with anti-inflammatory activity. However, these oils have poor storage stability and are mainly digested in the small intestine, which reduces their enrichment in the colon. After the oil is made into an oil-in-water emulsion, the oil droplets are embedded in natural polymer aggregates to construct microcapsules with a core-shell structure, which is an effective method to improve its stability during processing and storage. The advantage of this technology is that it can be embedded under low temperature conditions, with a high encapsulation rate, and the core-shell structure formed has a strong barrier effect to the external environment. However, how to use a suitable cross-linking method to make it have a certain stability in the upper gastrointestinal environment of the human body to ensure the delivery of active substances to the colon is an urgent problem to be solved.

[0003] The first challenge in preparing microcapsules using the coacervation method is to inhibit the aggregation of the coacervate phase to prevent it from affecting the cross-linking reaction. Currently, the most widely used and effective method is based on animal gelatin-polysaccharide complex coacervation. This is because cooling can cause the gelatin to form a gel, thereby fixing the morphology of the microcapsules. Drying and fixing the gelatin or cross-linking the coacervate phase with transglutaminase and tannic acid will not affect its morphology. However, existing methods cannot maintain the structural stability of oil microcapsules in the digestive environment of the stomach and small intestine, making it difficult to achieve the goal of colon-targeted delivery of polyunsaturated fatty acids.

[0004] In recent years, the development and utilization of widely available plant proteins has become a research hotspot for food proteins, aiming to reduce production costs, minimize environmental pollution, improve food protein safety, and meet the growing demand for protein. However, unlike animal gelatin, plant proteins cannot form gels upon cooling. Therefore, new methods are needed to inhibit the aggregation of the coacervate phase and, based on this, to crosslink the coacervate phase using specific crosslinking methods to produce microcapsules with a certain structural stability in the upper gastrointestinal environment, thereby achieving the goal of delivering polyunsaturated fatty acids to the colon. Summary of the Invention

[0005] To overcome the shortcomings and deficiencies of the aforementioned prior art, the primary objective of the present invention is to provide a method for preparing microcapsules for colon-targeted delivery of polyunsaturated fatty acids. Specifically, the method utilizes soybean 11S globulin and gum arabic as the microcapsule wall materials. Under certain pH conditions, the soybean 11S globulin and gum arabic are induced to undergo complex coagulation, causing the coacervates to wet oil droplets, forming a core-shell structure. The coacervates are further stabilized by glucan to inhibit aggregation. Furthermore, tannic acid, through hydrogen bonding and hydrophobic interactions with polysaccharides and proteins, further crosslinks the coacervates to produce microcapsules resistant to gastric and small intestinal digestion, enabling colonic delivery of polyunsaturated fatty acids.

[0006] Another object of the present invention is to provide colon-targeted delivery of polyunsaturated fatty acid oil microcapsules prepared by the above method.

[0007] Another object of the present invention is to provide the application of the above-mentioned colon-targeted delivery of polyunsaturated fatty acid oil microcapsules in the fields of food and medicine.

[0008] The purpose of the present invention is achieved through the following solutions:

[0009] A method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules comprises the following steps:

[0010] (1) Weigh soybean 11S globulin powder, add water and stir to dissolve, to obtain soybean 11S globulin solution;

[0011] (2) Weighing gum arabic powder, adding water and stirring to dissolve, to obtain a gum arabic solution;

[0012] (3) Weighing dextran powder, adding water and stirring to dissolve, to obtain a dextran solution;

[0013] (4) Weighing tannic acid powder, adding water and stirring to dissolve, to obtain a tannic acid solution;

[0014] (5) mixing the oil, the soybean 11S globulin solution of step (1), and the gum arabic solution of step (2) to obtain an emulsion;

[0015] (6) mixing the emulsion obtained in step (5), the soybean 11S globulin solution of step (1), and the gum arabic solution of step (2) under stirring, and adding acid to lower the pH of the solution;

[0016] (7) adding the glucan solution of step (3) to the dispersion obtained in step (6), and then stirring evenly;

[0017] (8) adding the tannic acid solution of step (4) to the dispersion obtained in step (7), and then stirring and reacting;

[0018] (9) The dispersion obtained in step (8) is centrifuged to remove the supernatant, and the precipitate is washed with water to obtain a microcapsule precipitate.

[0019] The soybean 11S globulin in step (1) is prepared by the following method:

[0020] Low-temperature defatted soybean meal is ground and then stirred evenly with water. The pH is adjusted to 7.5-8 with a sodium hydroxide solution and stirred at room temperature for 1.5-2 hours. After centrifugation, sodium bisulfite is added to the supernatant, which is then allowed to stand for 0.5-1 hour and then adjusted to pH 6.4 with an HCl solution. This solution is then allowed to stand at 4°C overnight and centrifuged to obtain a precipitate, which is primarily soybean 11S globulin. The resulting soybean 11S globulin precipitate is reconstituted with deionized water and freeze-dried to obtain soybean 11S globulin powder.

[0021] Low-temperature defatted soybean meal is ground and then mixed with water at a material-liquid ratio of 1:10-1:15 (mass ratio). The pH is adjusted to 7.5-8 with a 1-2 mol / L NaOH aqueous solution, stirred at low speed at room temperature for 1.5-2 hours, and centrifuged (8000-15000g, 15-30 minutes, 20°C). Sodium bisulfite (0.98g / L) is added to the supernatant, which is then allowed to stand for 0.5-1 hour before adjusting the pH to 6.4 with a 1-2 mol / L HCl aqueous solution. The solution is then allowed to stand at 4°C overnight and centrifuged (6500-15000g, 20-30 minutes, 4°C). The resulting precipitate, which is the main component of soybean 11S globulin, is reconstituted with deionized water and freeze-dried to obtain soybean 11S globulin powder.

[0022] The dissolution in step (1) is preferably carried out by stirring at 100-500 rpm for 1-2 hours until the protein is completely dissolved. The concentration of the soybean 11S globulin solution obtained in step (1) is 40-125 g / L, preferably 100 g / L.

[0023] The dissolution in step (2) is preferably carried out by stirring at 100-500 rpm for 1-2 hours until the gum is completely dissolved; the concentration of the gum arabic solution obtained in step (2) is 75-125 g / L, preferably 100 g / L.

[0024] The dissolution in step (3) is preferably carried out by stirring at 100-500 rpm for 1-2 hours until the mixture is completely dissolved; the concentration of the glucan obtained in step (3) is 40-200 g / L, preferably 100 g / L.

[0025] The dissolution in step (4) is preferably carried out by stirring at 100-500 rpm for 1-2 hours until the tannic acid is completely dissolved; the concentration of the tannic acid obtained in step (4) is 100-250 g / L, preferably 200 g / L.

[0026] In order to ensure that the soybean 11S globulin solution obtained in step (1) does not contain undissolved soybean 11S globulin and the gum arabic solution obtained in step (2) does not contain undissolved gum arabic, it is preferred to centrifuge and take the supernatant after adding water, stirring and dissolving.

[0027] The oil in step (5) is at least one of fish oil, soybean oil, linseed oil, sunflower oil and rice oil.

[0028] The amount of oil in step (5) satisfies that the volume of the oil accounts for 10%-30% of the total volume of the soybean 11S globulin solution, the gum arabic solution and the oil; the amounts of the soybean 11S globulin solution and the gum arabic solution satisfy that the mass ratio of soybean 11S globulin and gum arabic in the obtained emulsion is 1:1-1:2.5, and the volume ratio of the soybean 11S globulin solution and the gum arabic solution is preferably 1:1.

[0029] The specific preparation method of the emulsion described in step (5) is as follows:

[0030] After mixing the soybean 11S globulin solution and the gum arabic solution, add oil and then homogenize with a high-speed shear homogenizer at 8000-15000 rpm for 3-10 minutes, preferably 5 minutes.

[0031] The amount of the emulsion in step (6) satisfies that the emulsion accounts for 5-10% of the total volume of the solution finally formed in step (6); the amounts of the soybean 11S globulin solution and the gum arabic solution added in step (6) satisfy that the mass ratio of the added soybean 11S globulin to the gum arabic is 1:1:-1:2.5;

[0032] The stirring in step (6) is preferably carried out at 500-1000 rpm for 1-5 min;

[0033] The acid described in step (6) is preferably a 0.1-1 mol / L HCl aqueous solution; the addition of acid in step (6) to lower the pH of the solution means to lower the pH to 2.8-3.2, preferably 3.0.

[0034] The molecular weight of the dextran described in step (7) is 150-500 KDa;

[0035] The amount of the glucan solution in step (7) is such that the final concentration of glucan in the mixed solution of the dispersion and the glucan solution in step (7) is 20-100 g / L, preferably 50 g / L.

[0036] The amount of the tannic acid solution in step (8) is such that the final concentration of tannic acid in the mixed solution of the dispersion and the tannic acid solution in step (8) is equal to 10-25 g / L, preferably 20 g / L;

[0037] The reaction in step (8) is carried out at room temperature for 6-24 hours, preferably 12-18 hours.

[0038] The centrifugal conditions described in step (9) should meet the centrifugal force of 1000-3000g and the centrifugal time of 10-15min.

[0039] A colon-targeted delivery polyunsaturated fatty acid oil microcapsule prepared by the above method.

[0040] The above-mentioned colon-targeted delivery of polyunsaturated fatty acid oil microcapsules is used in food and in the preparation of anti-colitis drugs.

[0041] The mechanism of the present invention is:

[0042] This invention uses soybean 11S globulin and gum arabic as the microcapsule wall materials. Under certain pH conditions, complex coacervation of the protein and polysaccharide is induced, allowing them to fully wet the oil droplets and form a uniform core-shell structure. The coacervate phase is coated with dextran to prevent aggregation between different microcapsules, resulting in stable microcapsules. Furthermore, tannic acid is used to form hydrogen bonds with protein to non-covalently crosslink the polysaccharides in the coacervate phase. The microcapsules obtained by this method maintain structural integrity in the digestive environments of the stomach and small intestine, enabling colon-targeted delivery of fat-soluble active substances. Its significant advantages include: 1) Traditional microcapsule preparation based on complex coacervation primarily utilizes animal protein-polysaccharide complex coacervation, which is relatively expensive. This invention utilizes soybean 11S globulin instead of animal protein, thereby reducing raw material costs; 2) By coating the coacervate phase with dextran, the invention avoids microcapsule aggregation; and 3) the crosslinker tannic acid utilized in this invention is a natural plant compound with no toxic side effects, a widely available source, and low cost.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] The present invention fully utilizes the property of agglomerates wetting the oil droplet interface to obtain microcapsules with a core-shell structure. The production process involved is simple to operate, easy to control, and has low requirements on equipment.

[0045] The present invention utilizes dextran to inhibit the aggregation between microcapsules, thereby overcoming the bottleneck problem that the aggregation easily occurs during the cross-linking process of the coacervate phase and causes the core-shell structure to be destroyed.

[0046] The present invention utilizes tannic acid cross-linking to achieve structural stability of the microcapsules in the upper digestive tract. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The microstructure of the microcapsules prepared in Example 1 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0048] Figure 2 The microstructure of the microcapsules prepared in Example 2 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0049] Figure 3 The microstructure of the microcapsules prepared in Example 3 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0050] Figure 4 The microstructure of the microcapsules prepared in Example 4 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0051] Figure 5 is the free fatty acid concentration of the microcapsules prepared in Example 4 in the simulated gastrointestinal digestive fluid in vitro.

[0052] Figure 6 The free fatty acid concentration of the microcapsules prepared in Example 4 in the simulated colon fermentation broth of mouse feces in vitro.

[0053] Figure 7 The microstructure of the microcapsules prepared in Example 4 in the simulated colon fermentation broth of mouse feces in vitro.

[0054] Figure 8 The microstructure of different components of the microcapsules prepared in Comparative Example 1.

[0055] Figure 9 The microstructure of the microcapsules prepared in Comparative Example 2 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0056] Figure 10 The microstructure of the microcapsules prepared in Comparative Example 3 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0057] Figure 11 The microstructure of the microcapsules prepared in Comparative Example 4 in the simulated gastrointestinal digestive fluid in vitro, where A represents undigested, B represents gastric digestion for 2 hours, and C represents small intestinal digestion for 2 hours.

[0058] Figure 12 The microstructure of the microcapsules prepared in Comparative Example 5, wherein A represents pH 3.0, B represents pH 3.5, and C represents pH 4.0. DETAILED DESCRIPTION

[0059] The present invention will be described in further detail below in conjunction with the examples and accompanying drawings, but the embodiments of the present invention are not limited thereto. Where specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The reagents used in the examples can be purchased conventionally from the market unless otherwise specified.

[0060] In the following examples and comparative examples, the method for determining the microstructure of the microcapsules is as follows:

[0061] Oil was stained with Oil Red O. The microcapsules were reconstituted with water to obtain a microcapsule dispersion, which was then placed in a sample tank. The microstructure of the sample was observed using a Nikon inverted fluorescence microscope in bright-field mode. Red represents oil droplets.

[0062] In the examples, soybean 11S globulin powder was prepared by the following method: low-temperature defatted soybean meal was ground, then water was added at a mass ratio of 1:15, stirred, and the pH was adjusted to 7.5 with 2 mol / L NaOH. The mixture was stirred at low speed for 2 hours at room temperature, centrifuged (8000g, 30 minutes, 20°C), and sodium bisulfite (0.98g / L) was added to the supernatant. After standing for 0.5 hours, the pH was adjusted to 6.4 with 2 mol / L HCl. The mixture was allowed to stand at 4°C overnight and then centrifuged (6500g, 20 minutes, 4°C). The resulting precipitate contained soybean 11S globulin, the main component of which was 11S globulin. The resulting 11S globulin precipitate was reconstituted with deionized water and freeze-dried to obtain soybean 11S globulin powder.

[0063] The emulsion in the embodiment was prepared by the following method: 100 g / L soybean 11S globulin solution and 100 g / L gum arabic solution were mixed in a volume ratio of 1:1, and oil was added so that its amount accounted for 30% of the total volume of the solution; and the emulsion was obtained by homogenizing at 10000 rpm for 5 minutes using a high-speed shear homogenizer to obtain the emulsion.

[0064] The in vitro simulated gastrointestinal digestion solution in the examples was prepared by the following method: Based on the internationally recognized standardized method INFOGEST for in vitro simulated gastrointestinal digestion, simulated gastric fluid (SGF) digestion was performed by mixing the microcapsule dispersion after reconstitution with deionized water with simulated gastric fluid (SGF) at a ratio of 1:1 (v / v). The simulated gastric fluid (SGF) contained KCl: 6.9 mmol / L, KH2PO4: 0.9 mmol / L, NaHCO3: 25 mmol / L, NaCl: 47.2 mmol / L, MgCl2(H2O)6: 0.1 mmol / L, (NH4)2CO3: 0.5 mmol / L, pepsin, and CaCl2. The pepsin concentration in the microcapsule dispersion and SGF mixture reached 2000 U / mL, the CaCl2 concentration was 0.075 mM, the pH was adjusted to 3.0, the temperature was controlled at 37°C, and the digestion time was 120 min. Simulated intestinal fluid (SIF) digestion: The simulated gastric chyme obtained after the previous simulated gastric fluid digestion was mixed with simulated intestinal fluid (SIF) in a ratio of 1:1 (v / v). The simulated intestinal fluid SIF contained KCl: 6.8mmoL / L, KH2PO4: 0.8mmoL / L, NaHCO3: 85mmoL / L, NaCl: 38.4mmoL / L, MgCl2(H2O)6: 0.33mmoL / L, pancreatic enzymes, bile salts, CaCl2. The pancreatic enzyme concentration in the above-mentioned mixture of simulated gastric chyme and SIF reached 100U / mL, the CaCl2 concentration was 0.3mM, the final bile salt concentration was 10mM, the pH was adjusted to 7.0, the temperature was controlled at 37°C, and the digestion time was 120min.

[0065] The solution for simulating in vitro colonic fermentation using mouse feces in the embodiment was prepared by the following method: bacterial mother liquor: 1g of feces from 5 mice was mixed with phosphate buffer (pH 7.2-7.4) at a ratio of 1:10 (m / V, g / mL), and then homogenized in a vortex mixer for 2 minutes. The homogenized mouse feces mixture was passed through 4 layers of medical gauze, solid particles were filtered out, and a fecal bacterial suspension was obtained. It was then inoculated into a preculture medium (10g / L tryptone, 5g / L yeast powder, 10g / L sodium chloride, 5g / L glucose, 6g / L maltose, pH 6.83±0.04) at a ratio of 16% for pre-culture. After fermentation at 37°C for 18h (anaerobic), a bacterial mother liquor was obtained.

[0066] Carbon-free medium: contains 2 g / L soy peptone, 2 g / L yeast extract, 0.1 g / L sodium chloride, 0.04 g / L potassium dihydrogen phosphate, 0.01 g / L magnesium sulfate heptahydrate, 0.01 g / L calcium chloride hexahydrate, 2 g / L sodium bicarbonate, 2 mL / L Tween 80, 10 uL / L vitamin K1, 0.5 g / L L-cysteine hydrochloride, and 0.5 g / L bile salts. The pH value is adjusted to 6.83, and the medium is sterilized by autoclaving.

[0067] Example 1

[0068] This embodiment provides a method for preparing polyunsaturated fatty acid oil microcapsules for colon-targeted delivery, comprising the following steps:

[0069] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0070] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0071] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0072] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) at 1000 rpm to make the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1. Subsequently, 1 mol / L hydrochloric acid was added to adjust the pH value of the mixed solution to 3.0;

[0073] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0074] (6) Add tannic acid aqueous solution (concentration of 200 g / L) to the dispersion in (5) to make the final concentration of tannic acid 20 g / L, then stir at 1000 rpm and react at room temperature for 12 h;

[0075] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with deionized water and centrifuged to remove the unreacted glucan and tannic acid in the solution to avoid interference with the test of microcapsule digestion ability. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 100 g / L. The microcapsule dispersion was mixed with simulated gastric fluid at a volume ratio of 1:1, the pH was adjusted to 3.0, and the mixture was stirred in a 37°C water bath at 100 rpm for 2 h. The simulated gastric chyme obtained after the above simulated gastric fluid digestion was mixed with simulated intestinal fluid at a volume ratio of 1:1, the pH was adjusted to 7.0, and the mixture was stirred in a 37°C water bath at 100 rpm for 2 h.

[0076] The microstructure of the microcapsules prepared by this method is as follows Figure 1 , which represent, from left to right, the morphology of undigested microcapsules, the morphology of microcapsules after 2 hours of gastric digestion, and the morphology of microcapsules after 2 hours of small intestinal digestion.

[0077] Example 2

[0078] This embodiment provides a method for preparing polyunsaturated fatty acid oil microcapsules for colon-targeted delivery, comprising the following steps:

[0079] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0080] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0081] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0082] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm, so that the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) was 10%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1, and then 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0;

[0083] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0084] (6) Add tannic acid aqueous solution (concentration of 200 g / L) to the dispersion in (5) to make the final concentration of tannic acid 20 g / L, then stir at 1000 rpm and react at room temperature for 18 h;

[0085] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with deionized water and centrifuged to remove the unreacted glucan and tannic acid in the solution to avoid interference with the test of microcapsule digestion ability. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 100 g / L. The microcapsule dispersion was mixed with simulated gastric fluid in a volume ratio of 1:1, the pH was adjusted to 3.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h. The simulated gastric chyme obtained after digestion with the simulated gastric fluid was mixed with simulated intestinal fluid in a volume ratio of 1:1, the pH was adjusted to 7.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h.

[0086] The microstructure of the microcapsules prepared by this method is as follows Figure 2 , which represent, from left to right, the morphology of undigested microcapsules, the morphology of microcapsules after 2 hours of gastric digestion, and the morphology of microcapsules after 2 hours of small intestinal digestion.

[0087] Example 3

[0088] This embodiment provides a method for preparing polyunsaturated fatty acid oil microcapsules for colon-targeted delivery, comprising the following steps:

[0089] (1) Weigh soybean 11S globulin powder and prepare a 50 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 50 g / L.

[0090] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0091] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0092] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) at 1000 rpm to make the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1. Subsequently, 1 mol / L hydrochloric acid was added to adjust the pH value of the mixed solution to 2.8;

[0093] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0094] (6) Add tannic acid aqueous solution (concentration of 110 g / L) to the dispersion in (5) to make the final concentration of tannic acid 10 g / L, then stir at 1000 rpm for 24 h at room temperature;

[0095] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with deionized water and centrifuged to remove the unreacted glucan and tannic acid in the solution to avoid interference with the test of microcapsule digestion ability. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 75 g / L. The microcapsule dispersion was mixed with simulated gastric fluid in a volume ratio of 1:1, the pH was adjusted to 3.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h. The simulated gastric chyme obtained after the above simulated gastric fluid digestion was mixed with simulated intestinal fluid in a volume ratio of 1:1, the pH was adjusted to 7.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h.

[0096] The microstructure of the microcapsules prepared by this method is as follows Figure 3 , which represent, from left to right, the morphology of undigested microcapsules, the morphology of microcapsules after 2 hours of gastric digestion, and the morphology of microcapsules after 2 hours of small intestinal digestion.

[0097] Example 4

[0098] This embodiment provides a method for preparing polyunsaturated fatty acid oil microcapsules for colon-targeted delivery, comprising the following steps:

[0099] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0100] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0101] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0102] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm, so that the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) was 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1, and then 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0;

[0103] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0104] (6) Add tannic acid aqueous solution (concentration of 200 g / L) to the dispersion in (5) to make the final concentration of tannic acid 20 g / L, then stir at 1000 rpm and react at room temperature for 18 h;

[0105] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with deionized water and centrifuged to remove the unreacted glucan and tannic acid in the solution to avoid interference with the microcapsule digestion test. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 100 g / L. The microcapsule dispersion was mixed with simulated gastric fluid in a volume ratio of 1:1 and the pH was adjusted to 3.0. The simulated gastric chyme obtained after digestion with the simulated gastric fluid was mixed with simulated intestinal fluid in a volume ratio of 1:1 and the pH was adjusted to 7.0. The mixture was stirred in a 37°C water bath at 100 rpm for 2 h.

[0106] (8) The free fatty acid concentration of the simulated gastrointestinal digestion in vitro in (6) was determined using the Solebo free fatty acid kit.

[0107] (9) In vitro colonic fermentation was simulated using mouse feces. The microcapsule dispersion after in vitro simulated gastrointestinal digestion in (7) was centrifuged (centrifugation parameters were 1000 rpm, 15 min). The microcapsules were taken out and added to a mixture of carbon-free culture medium and bacterial mother liquor. At this time, the ratio of microcapsules, carbon-free culture medium, and bacterial mother liquor was 1 g:45 mL:5 mL. The microcapsules were quickly sealed in an anaerobic culture bag. The microcapsule morphology was observed at 0 h, 8 h, 24 h, and 48 h, and the free fatty acid concentration was determined using Solebol free fatty acid reagent.

[0108] The microstructure of the microcapsules prepared by this method is as follows Figure 4 From left to right, the morphology of the undigested microcapsules, the morphology of the microcapsules after 2 hours of gastric digestion, and the morphology of the microcapsules after 2 hours of small intestinal digestion are represented. Figure 5 The free fatty acid concentration of microcapsules in vitro simulated colonic fermentation was as follows Figure 6 , microstructure such as Figure 7 , from left to right, they represent the microcapsule morphology after 0h, 8h, 24h, and 48h of simulated colon anaerobic fermentation in vitro.

[0109] Comparative Example 1

[0110] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0111] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0112] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0113] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm, so that the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) was 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1, and then 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0;

[0114] (5) Add tannic acid aqueous solution (concentration of 200 g / L) to the above dispersion to make the final concentration of tannic acid 20 g / L, then stir evenly at 1000 rpm for 18 h; take the dispersion and observe the morphology of the microcapsules.

[0115] The microstructure of the microcapsules prepared by this method is as follows Figure 8 In this comparative example, no dextran was added, resulting in the subsequent addition of tannic acid for cross-linking, which caused the microcapsules to aggregate and destroy the original core-shell structure.

[0116] Comparative Example 2

[0117] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0118] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0119] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0120] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm, so that the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) was 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1, and then 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0;

[0121] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0122] (6) Add tannic acid solution to the dispersion in (5) to a final concentration of 5 g / L, then stir at 1000 rpm and react at room temperature for 18 h;

[0123] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with water and centrifuged to remove the unreacted glucan and tannic acid in the solution to avoid interfering with the test of microcapsule digestion ability. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 100 g / L. The microcapsule dispersion was mixed with simulated gastric fluid in a volume ratio of 1:1 and the pH was adjusted to 3.0. After stirring in a 37°C water bath at 100 rpm for 2 h, the simulated gastric chyme obtained after digestion with the simulated gastric fluid was mixed with simulated intestinal fluid in a volume ratio of 1:1, the pH was adjusted to 7.0, and the mixture was stirred in a 37°C water bath at 100 rpm for 2 h.

[0124] The microstructure of the microcapsules prepared by this method is as follows Figure 9 In this comparative example, the final concentration of tannic acid added for cross-linking is outside the range specified in the present invention, the cross-linking of the microcapsules is unstable, the core-shell structure of the microcapsules is destroyed in the gastric digestive environment, and the structural integrity cannot be maintained.

[0125] Comparative Example 3

[0126] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0127] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0128] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0129] (4) The emulsion obtained in (3) was mixed uniformly with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm, so that the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) was 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1, and then 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0;

[0130] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0131] (6) Add tannic acid aqueous solution (concentration of 200 g / L) to the dispersion in (5) to make the final concentration of tannic acid 20 g / L, then stir at 1000 rpm and react for 0 h;

[0132] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with water and centrifuged to remove the unreacted glucan and tannic acid in the solution to avoid interference with the test of microcapsule digestion ability. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 100 g / L. The microcapsule dispersion was mixed with simulated gastric fluid in a volume ratio of 1:1, the pH was adjusted to 3.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h. The simulated gastric chyme obtained after the above simulated gastric fluid digestion was mixed with simulated intestinal fluid in a volume ratio of 1:1, the pH was adjusted to 7.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h.

[0133] The microstructure of the microcapsules prepared by this method is as follows Figure 10 In this comparative example, the reaction time of the tannic acid solution is outside the range specified in the present invention, the cross-linking of the microcapsules is unstable, the core-shell structure of the microcapsules is destroyed in the gastric digestive environment, and the structural integrity cannot be maintained.

[0134] Comparative Example 4

[0135] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0136] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0137] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0138] (4) The emulsion obtained in (3) was mixed with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm to make the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1, and then 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0;

[0139] (5) Add a 500 kDa dextran aqueous solution (concentration of 100 g / L) to the above dispersion to make the final concentration of dextran 50 g / L, and stir at 1000 rpm;

[0140] (6) Add 100 U / g soybean 11S globulin transglutaminase to the dispersion in (5), then stir evenly at 1000 rpm and heat at 37°C for 2 h;

[0141] (7) The dispersion in (6) was centrifuged at 1000 g for 15 min, the supernatant was removed, and the precipitate was washed twice with water and centrifuged to remove the transglutaminase that did not participate in the reaction in the solution to avoid interfering with the test of the microcapsule digestion ability. The microcapsule dispersion was then re-dissolved with deionized water to obtain a microcapsule dispersion with a concentration of 100 g / L. The microcapsule dispersion was mixed with simulated gastric fluid in a volume ratio of 1:1, the pH was adjusted to 3.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h. The simulated gastric chyme obtained after the above simulated gastric fluid digestion was mixed with simulated intestinal fluid in a volume ratio of 1:1, the pH was adjusted to 7.0, and the mixture was stirred in a water bath at 37°C at 100 rpm for 2 h.

[0142] The microstructure of the microcapsules prepared by this method is as follows Figure 11 In this comparative example, transglutaminase was used for cross-linking, and the microcapsule structure was unstable. The core-shell structure of the microcapsule was destroyed in the gastric digestive environment and could not maintain the integrity of the structure.

[0143] Comparative Example 5

[0144] (1) Weigh soybean 11S globulin powder and prepare a 100 g / L protein solution with deionized water. Stir at 100 rpm for 1 hour until completely dissolved, then centrifuge at 10,000 g for 30 minutes. Collect the supernatant for later use. The concentration of soybean 11S globulin in the supernatant is still 100 g / L.

[0145] (2) Gum arabic powder was weighed and a 100 g / L polysaccharide solution was prepared with deionized water. The solution was stirred at 100 rpm for 1 hour until completely dissolved. The solution was then centrifuged at 10,000 g for 30 minutes. The supernatant was collected for later use. The concentration of gum arabic in the supernatant was still 100 g / L.

[0146] (3) After the protein and polysaccharide solutions were mixed in a volume ratio of 1:1, 30% soybean oil was added (as a percentage of the total volume of the soybean 11S globulin solution, gum arabic solution, and oil), mixed, and homogenized at 10,000 rpm for 5 minutes to obtain an emulsion;

[0147] (4) The emulsion obtained in (3) was mixed with the soybean 11S globulin solution and the gum arabic solution obtained in (1) and (2) under stirring conditions of 1000 rpm to make the volume fraction of the emulsion (the percentage of the total volume of the emulsion, soybean 11S globulin solution and gum arabic solution after mixing) 5%. At this time, the volume ratio of the added soybean 11S globulin solution to the gum arabic solution was 1:1. Subsequently, 1 mol / L hydrochloric acid was added to adjust the pH value of the solution to 3.0, 3.5 and 4.0, respectively, and stirred at 1000 rpm for uniformity.

[0148] The microstructure of the microcapsules prepared by this method is as follows Figure 12 In this comparative example, pH 3.0 is within the pH range specified in the present invention and can form core-shell structure microcapsules, while pH 3.5 and pH 4.0 are outside the pH range specified in the present invention and cannot form core-shell structure microcapsules.

[0149] Colon-targeted delivery of polyunsaturated fatty acid oil microcapsules prepared based on the complex coacervation of soybean 11S globulin and gum arabic can only be achieved under the conditions specified in the present invention. Any conditions beyond the specified conditions will be detrimental to the formation of microcapsules. This is because the coacervate phase of soybean 11S globulin and gum arabic can only completely wet the oil droplets to form a core-shell structure at a specific pH value. Controlling the formation of the coacervate phase to encapsulate the oil droplets to form a core-shell structure is the first step in preparing microcapsules. However, even if the core-shell structure is formed, the coacervate phase has fluidity and can fuse with each other, which will cause the microcapsules to agglomerate. Therefore, the present invention continues to use a certain concentration of glucan to coat the coacervate phase to avoid agglomeration between different microcapsules. On this basis, the coacervate phase is cross-linked with tannic acid at the same time to give the microcapsules structural stability in the digestive environment of the stomach and small intestine.

[0150] Depend on Figure 1-4 (Examples 1-4) It can be found that in the dispersion of soybean 11S globulin and gum arabic complex coacervation microcapsules prepared by the method of the present invention, the obtained microcapsules are wrapped with oil droplets inside, showing a core-shell structure. On this basis, tannic acid can form hydrogen bonds with polysaccharides and proteins, and hydrophobic interactions can occur to further cross-link the coacervation phase. The microcapsules obtained by the above means can maintain structural integrity in the digestive environment of the stomach and small intestine, and achieve colon-targeted delivery of fat-soluble active substances. At present, microcapsules prepared based on complex coacervation are easy to aggregate, and it is difficult to effectively maintain the structural stability of the microcapsules in the digestive tract. The present invention overcomes the problems existing in the traditional microcapsule preparation based on the coacervation method, and the process is simple, easy to control and operate. In addition, the microcapsules prepared by the above means can maintain structural integrity in the digestive environment of the stomach and small intestine, and achieve colon-targeted delivery of fat-soluble active substances. At present, microcapsules prepared based on complex coacervation are easy to aggregate, and it is difficult to effectively maintain the structural stability of the microcapsules in the digestive tract. The present invention overcomes the problems existing in the traditional microcapsule preparation based on the coacervation method, and the process is simple, easy to control and operate. In addition, Figure 5-7 (Example 4) It was found that when simulating gastrointestinal digestion in vitro, the free fatty acid concentration of the microcapsules was low, indicating that the microcapsules can maintain structural integrity in the stomach and small intestine, preventing the release and decomposition of fat-soluble active substances, and achieving the possibility of colon-targeted delivery. In the colon environment, however, the free fatty acid concentration increased, and microscopic morphology showed that the microcapsules were destroyed. This indicates that after targeted delivery to the colon, the outer shell of the microcapsules can be digested by intestinal microorganisms, and the fat-soluble active substances inside are slowly released, achieving the purpose of the present invention's colon-targeted delivery of polyunsaturated fatty acid oil microcapsules prepared by complex coacervation of soybean 11S globulin and gum arabic.

[0151] Depend on Figure 8 (Comparative Example 1) It was found that if no dextran was added, the coacervate phase agglomerated.

[0152] Depend on Figure 9 (Comparative Example 2) It can be found that if the final concentration of the added tannic acid solution is outside the range specified in the present invention, the core-shell structure of the microcapsule is destroyed in the gastric digestive environment and cannot maintain structural integrity.

[0153] Depend on Figure 10 (Comparative Example 3) It can be found that if the reaction time after adding the tannic acid solution is outside the range specified in the present invention, the core-shell structure of the microcapsule is destroyed in the gastric digestive environment and cannot maintain structural integrity.

[0154] Depend on Figure 11 (Comparative Example 4) It can be found that if the cross-linking agent used is outside the range specified in the present invention after adding transglutaminase, the core-shell structure of the microcapsule is destroyed in the gastric digestive environment and cannot maintain structural integrity.

[0155] Depend on Figure 12 (Comparative Example 5) It can be found that if the pH value is outside the range specified by the present invention, the morphology of the microcapsules is disordered and the core-shell structure cannot be formed.

[0156] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules, characterized in that The following steps are involved: (1) Weigh soybean 11S globulin powder, add water and stir to dissolve, to obtain soybean 11S globulin solution; (2) Weighing gum arabic powder, adding water and stirring to dissolve, to obtain a gum arabic solution; (3) Weighing dextran powder, adding water and stirring to dissolve, to obtain a dextran solution; (4) Weighing tannic acid powder, adding water and stirring to dissolve, to obtain a tannic acid solution; (5) mixing the oil, the soybean 11S globulin solution of step (1), and the gum arabic solution of step (2) to obtain an emulsion; (6) mixing the emulsion obtained in step (5), the soybean 11S globulin solution of step (1), and the gum arabic solution of step (2) under stirring, and adding acid to lower the pH of the solution; (7) adding the glucan solution of step (3) to the dispersion obtained in step (6), and then stirring evenly; (8) adding the tannic acid solution of step (4) to the dispersion obtained in step (7), and then stirring and reacting; (9) The dispersion obtained in step (8) is centrifuged to remove the supernatant, and the precipitate is washed with water to obtain a microcapsule precipitate.

2. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The soybean 11S globulin in step (1) is prepared by the following method: The low-temperature defatted soybean meal is crushed and then stirred evenly with water. The pH is adjusted to 7.5-8 with a NaOH aqueous solution and stirred at room temperature for 1.5-2 hours. After centrifugation, sodium bisulfite is added to the supernatant, and after standing for 0.5-1 hour, the pH is adjusted to 6.4 with an HCl aqueous solution. The material solution is placed at 4°C and allowed to stand overnight. The precipitate obtained by centrifugation is re-dissolved with water and freeze-dried to obtain soybean 11S globulin powder.

3. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The oil in step (5) is at least one of fish oil, soybean oil, linseed oil, sunflower oil and rice oil.

4. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The concentration of the soybean 11S globulin solution obtained in step (1) is 40-125 g / L; The concentration of the gum arabic solution obtained in step (2) is 75-125 g / L; The amount of oil in step (5) satisfies that the volume of the oil accounts for 10%-30% of the total volume of the soybean 11S globulin solution, the gum arabic solution and the oil; the amounts of the soybean 11S globulin solution and the gum arabic solution satisfy that the mass ratio of soybean 11S globulin to gum arabic in the obtained emulsion is 1:1-1:2.

5.

5. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The specific preparation method of the emulsion described in step (5) is as follows: After mixing the soybean 11S globulin solution and the gum arabic solution, add oil and then homogenize with a high-speed shear homogenizer at 8000-15000 rpm for 3-10 minutes.

6. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The amount of the emulsion in step (6) is such that the emulsion accounts for 5-10% of the total volume of the solution finally formed in step (6); the amounts of the soybean 11S globulin solution and the gum arabic solution added in step (6) are such that the mass ratio of the added soybean 11S globulin to the gum arabic is 1:1-1:2.5; Adding acid in step (6) to lower the pH of the solution means lowering the pH to 2.8-3.

2.

7. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The concentration of the glucan obtained in step (3) is 40-200 g / L; The molecular weight of the dextran described in step (7) is 150-500 KDa; The amount of the glucan solution in step (7) is such that the final concentration of glucan in the mixed solution of the dispersion and the glucan solution in step (7) is 20-100 g / L.

8. The method for preparing colon-targeted polyunsaturated fatty acid oil microcapsules according to claim 1, characterized in that: The concentration of tannic acid obtained in step (4) is 100-250 g / L; The amount of the tannic acid solution in step (8) is such that the final concentration of tannic acid in the mixed solution of the dispersion and the tannic acid solution in step (8) is equal to 10-25 g / L; The reaction in step (8) is carried out at room temperature for 6-24 hours.

9. A colon-targeted delivery polyunsaturated fatty acid oil microcapsule prepared according to the method according to any one of claims 1 to 8.

10. Use of the colon-targeted delivery polyunsaturated fatty acid oil microcapsules according to claim 9 in food and in the preparation of anti-colitis drugs.

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