A high expansion rate algae dietary fiber sustained-release capsule and its preparation method and application

Abstract

The present invention relates to a high expansion rate algae dietary fiber sustained-release capsule and its preparation method and application, the sustained-release capsule, including a core material and a wall material, the mass ratio of the core material to the wall material is 1: (1-3); in parts by mass, the core material includes 15-25 parts of probiotics, 5-15 parts of carboxymethyl cellulose, and 5-10 parts of chitosan; the wall material includes 20-30 parts of algae dietary fiber and 10-20 parts of resistant dextrin, and the core material forms a self-assembled coating on the surface of the probiotics through the electrostatic adsorption of carboxymethyl cellulose and chitosan; the expansion force of the algae dietary fiber is greater than 100mL / g, and the water holding capacity is greater than 10000%; the core material and the wall material are prepared by a negative pressure low-temperature spray drying method to obtain the sustained-release capsule. The wall material algae dietary fiber and the resistant dextrin of the sustained-release capsule of the present invention have a good taste, increase satiety, and are combined with the core material probiotics released by intestinal positioning to contribute to intestinal peristalsis and promote intestinal health.

Description

Technical Field

[0001] The invention belongs to the technical field of algae dietary fiber extraction and application, and in particular relates to a high-swelling-rate algae dietary fiber sustained-release capsule and a preparation method and application thereof. Background Art

[0002] Dietary fiber, known as the "body's scavenger," promotes the excretion of bile acid and neutral steroids, lowers cholesterol, promotes bowel movements, increases satiety, aids in detoxification and beauty, prevents constipation, and slows carbohydrate absorption, helping to control blood sugar. Seaweed foods, including Nostoc, Laver, Kelp, Sea lettuce, and Wakame, are extremely high in dietary fiber and minerals such as calcium, iron, sodium, magnesium, phosphorus, and iodine. Seaweed fiber possesses excellent water-binding and swelling capacity, and the ability to absorb saturated and unsaturated fats. It is rich in alginate, cellulose, hemicellulose, vitamins, and minerals, and contains a high content of soluble polysaccharides, making it a high-quality raw material for extracting highly active dietary fiber. Seaweed fiber has laxative effects, anti-cancer and cancer prevention properties, prevents cardiovascular and cerebrovascular disease, promotes weight loss, and lowers blood sugar. The high calcium content in seaweed fiber not only supplements the body's calcium needs but also serves as a barrier to the absorption of side chain groups, such as hydroxyl and carboxyl groups, preventing these groups from affecting mineral metabolism in the intestines.

[0003] my country's kelp production and scale are both ranked first in the world. In 2009, the output of dried kelp in my country reached 6.0×10 5 t, accounting for over 50% of the world's total production. Besides being consumed directly, kelp is one of the main raw materials for the brown algae industry. In my country, kelp processing has established an industrial system with alginate, mannitol, and iodine as its main products. However, due to the low added value of these products, the high water and energy consumption of the production process, severe pollution, and a large proportion of waste, production costs remain high, putting increasing pressure on the environment. Furthermore, with the continuous improvement of people's living standards, the variety of refined foods has gradually increased, the balance between meat and vegetarian diets has gradually shifted, and dietary fiber intake is declining. Diseases of civilization caused by dietary imbalance, such as obesity, hypertension, and diabetes, have become more common, especially in economically developed coastal cities. Therefore, how to obtain high-quality, efficient, and low-pollution algae dietary fiber while maintaining its biological activity and promoting its metabolic health benefits has become a hot topic in research on dietary fiber functional foods and pharmaceuticals.

[0004] Patent CN110074418B discloses a method for extracting seaweed dietary fiber, in which the seaweed is first subjected to a steam explosion wall pretreatment, and then subjected to three enzymatic hydrolysis, acid-base treatment, and deodorization and activation extractions to obtain the seaweed dietary fiber. This invention uses a method combining chemical reagents with enzyme reagents to extract seaweed dietary fiber. The dietary fiber extraction rate is high (up to 41.77%), and the swelling power (up to 278.90 mL / g) and water holding capacity (up to 11892.69%) are high, and there is no fishy smell. Dietary fiber has good physiological functions and helps intestinal motility, carbohydrate and lipid metabolism, etc. This invention focuses on the extraction method of seaweed dietary fiber, and does not involve the protection of dietary fiber during the application process, synergistic effects, etc. Its materials are relatively single and it is difficult to meet actual use needs.

[0005] Patent CN114931562A discloses a microcapsule delivery system based on insoluble dietary fiber. The microcapsules are prepared by a microfluidic process and include a microcapsule wall material and a microcapsule core material. The wall material is composed of sodium alginate and insoluble dietary fiber, and the core material is composed of core components, which are probiotics, health product efficacy ingredients, medicines, food functional factors and other substances suitable for embedding. The use of kelp nanocellulose-based microcapsules maintains a good spherical shape in the stomach, significantly improves the protection of the core components, and can quickly release the core components in the intestine, playing a good gastrointestinal sustained-release function. The microcapsules prepared by the present invention have a particle size of less than 500 μm and good monodispersity. The preparation method is simple to operate and low in cost. This patent introduces a microcapsule structure and uses sodium alginate and insoluble dietary fiber as wall materials to provide good gastrointestinal sustained-release function for the probiotics in the core. However, due to the limitation of insoluble dietary fiber, this product is difficult to provide a sense of fullness in the stomach. Moreover, due to the relatively simple coating ingredients and structure, the wall material will still disintegrate to a certain extent under the action of gastric acid dissolution and swelling, resulting in the risk of inactivation of the probiotics inside.

[0006] Therefore, what kind of composition and structure should be provided to rationally utilize algae dietary fiber and other active substances, so as to achieve the effects of providing a sense of fullness in the stomach and promoting intestinal health. Summary of the Invention

[0007] To address the shortcomings of the aforementioned prior art, the present invention provides a high-expansion-rate algae dietary fiber sustained-release capsule, as well as its preparation method and application. Electrostatic adsorption is utilized to form a carboxymethyl cellulose-chitosan self-assembly coating on the probiotic surface, providing a core material that allows for sustained gastrointestinal release and targeted intestinal release. A wall material containing algae dietary fiber, resistant dextrin, and carboxymethyl cellulose is then stably coated around the core material, providing a long-lasting and significant feeling of fullness.

[0008] In a first aspect, the present invention provides a high expansion rate algae dietary fiber sustained-release capsule, comprising a core material and a wall material, wherein the mass ratio of the core material to the wall material is 1:(1-3);

[0009] The core material includes the following components in parts by mass:

[0010] 15-25 servings of probiotics

[0011] 5-15 parts of carboxymethyl cellulose

[0012] 5-10 parts of chitosan;

[0013] Wall materials include the following components:

[0014] 20-30 servings of algae dietary fiber

[0015] 10-20 parts of resistant dextrin;

[0016] The core material forms a self-assembled coating layer on the surface of the probiotics through the electrostatic adsorption of carboxymethyl cellulose and chitosan;

[0017] The algae dietary fiber has a swelling capacity greater than 100 mL / g and a water holding capacity greater than 10,000%;

[0018] The core material and the wall material are prepared into the sustained-release capsule by a negative pressure low-temperature spray drying method.

[0019] Chitosan, as a carrier, can stabilize the core material components, promote core material absorption, slow or control dissolution, help the core material reach target organs, and prevent gastric irritation. The surface of chitosan microspheres is rich in polysaccharide chains, which can be recognized by specific cells or tissues, allowing targeted delivery of the core material to the target site for storage and release. Drug release from chitosan-loaded microspheres is related to chitosan molecular weight. Generally, the release rate of the core material decreases with increasing chitosan molecular weight, and higher chitosan concentrations result in a lower rate of diffusion of the core material from the chitosan matrix into the biological medium.

[0020] Carboxymethyl cellulose is a low-cost and readily available anionic cellulose derivative commonly used in food processing. - NH 3+ Strong electrostatic interactions exist between the layers, allowing them to self-assemble into a stable layered coating structure. This layered coating offers excellent barrier properties to oil and water, providing long-lasting protection for the core material. In practical applications, when the product is used with carriers such as water and beverages, or in combination with other substances, the core material protected by this self-assembled coating maintains excellent stability, preventing rapid structural collapse that could lead to core material inactivation and failure, thus demonstrating its high application value.

[0021] Specifically, preferably, the chitosan has a viscosity-average molecular weight of 500-1000 KD and a deacetylation degree of 70-95%; the carboxymethyl cellulose has a viscosity-average molecular weight of 15000-25000 KD and a substitution degree higher than 55%.

[0022] The present invention uses algae dietary fiber in the wall material. Through reasonable processing, it is possible to obtain dietary fiber with a swelling power greater than 100 mL / g, preferably greater than 120 mL / g, more preferably greater than 150 mL / g, and a water holding capacity greater than 10,000%, preferably greater than 11,000%, and more preferably greater than 12,000%. It has a good swelling effect, can provide a significant sense of fullness, and retains the nutritional components and activity of the algae dietary fiber.

[0023] In addition to using algae dietary fiber in the wall material, the present invention also adds another dietary fiber, resistant dextrin. Resistant dextrin is a low-calorie glucan that can be fermented by microorganisms in the human digestive tract into short-chain fatty acids. These short-chain fatty acids can increase satiety, reduce people's food intake, and help achieve the effect of weight control. After entering the human digestive system, resistant dextrin will turn into dextrin. This dextrin is digested slowly and can delay the digestion and absorption of carbohydrates, thereby reducing blood sugar response. It is then fermented by intestinal microorganisms to produce short-chain fatty acids, which promote intestinal health.

[0024] Preferably, the probiotics are selected from at least one of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium, Lactobacillus brevis, and Lactobacillus plantarum. Preferably, the viable count of the probiotics is ≥5×10 9 CFU / ml, more preferably the probiotics are compounded, such as Streptococcus thermophilus and Lactobacillus bulgaricus.

[0025] Preferably, the algae dietary fiber is prepared by the following steps:

[0026] (1) Pretreatment: soaking the algae raw material in water, washing it, crushing it, and mixing it with water to obtain algae paste;

[0027] (2) Enzymolysis: adding complex enzyme to the algae paste, enzymolyzing and cooling to obtain enzymolysis material;

[0028] (3) Acid-base treatment: add hydrochloric acid to the enzymatic hydrolysis material to adjust the pH to 2-4, filter and collect the residue; wash the residue to remove Cl - , after draining, add it to a sodium carbonate aqueous solution for reaction, cool it down and add hydrochloric acid to neutralize it to a pH of 6-7;

[0029] (4) Gelation treatment: adding calcium chloride solution to gel, filtering and collecting the residue, and washing to obtain a water-containing crude product;

[0030] (5) Deodorization: Add the crude product containing water to a yeast aqueous solution with a concentration of 1-6 w / v%, preferably 4-6 w / v%, and stir at 20-30°C for 20-60 minutes, centrifuge, wash, and filter to collect the deodorized residue;

[0031] (6) activating the deodorized filter residue with a sodium chloride solution to obtain an activated crude product;

[0032] (7) freeze-drying the activated crude product and crushing it to obtain algae dietary fiber.

[0033] The present invention uses multi-stage enzymatic hydrolysis to gently remove impurities such as protein, starch, and fat. The deodorization and odor removal of seaweed dietary fiber has a great impact on its user experience. The present invention uses yeast deodorization to ensure that the nutritional components of seaweed are not damaged, and the yeast can be reused after separation. The acid-base treatment process can fully remove impurities such as protein and fat, and maximize the extraction of dietary fiber. The addition of calcium chloride in the early extraction process is beneficial to reduce the loss of dietary fiber and the convenience of operation, but it is easy to reduce the activity of dietary fiber. Therefore, sodium chloride is used for functional activation treatment in the subsequent process, so as to take into account the extraction rate and activity of seaweed dietary fiber.

[0034] Preferably, in step (2), the enzymatic hydrolysis process of the complex enzyme includes:

[0035] (2.1) Add yeast solution to algae paste and maintain the temperature at 25-35°C for 2-5 hours;

[0036] (2.2) Add cellulase aqueous solution, increase the temperature at a rate of 1-3°C / min, maintain the temperature at 50±2°C while stirring, and perform enzymatic hydrolysis for 1-2 hours;

[0037] (2.3) Add protease aqueous solution and heat to 55±1°C at a rate of 0.5-1°C / min. Then, maintain the temperature at 50±2°C for enzymatic hydrolysis for 1-2 hours while stirring, and then cool to 35±2°C.

[0038] The enzymatic hydrolysis process of the present invention adopts a hierarchical enzymatic hydrolysis and a gradual temperature increase method, which can exert the enzymatic hydrolysis effect in a more gentle and controllable manner.

[0039] Preferably, the freezing temperature of freeze-drying is -60°C to -40°C, the vacuum degree is 10 to 50 Pa, and the algae dietary fiber is crushed to 2-30 μm; preferably, in the particle size distribution obtained by laser diffraction scattering method, the average particle size D50 is 5-20 μm, the particle size D10 with a cumulative frequency of 10% starting from the small particle size side is 2-8 μm, and Dx expressed by Dx = (D50-D10) / D50 is in the range of greater than 0.4 and less than 0.8, thereby taking into account the comprehensive performance of the fiber such as low loss rate, high expansion force and high water holding capacity.

[0040] By combining freeze-drying with cryogenic pulverization, using liquid nitrogen as a cooling source, the material to be pulverized becomes frozen and brittle at low temperatures, while vacuuming the material to remove moisture by sublimation. The loose, fragile material enters the pulverizer's pulverizing chamber, where it is pulverized through the high-speed rotation of the impeller. The pulverization is achieved through repeated impact, collision, shearing, and friction between the material, the blades, the gears, and each other. The resulting powder has a narrower particle size distribution and a larger specific surface area, improving the water-holding and expansion capacity of dietary fiber, making it more uniform, and resulting in a looser structure.

[0041] Preferably, the core material is prepared by the following steps:

[0042] Step 1: spraying the carboxymethyl cellulose aqueous solution onto the probiotics and drying with hot air to obtain a coating coated with carboxymethyl cellulose; in order to completely coat the probiotics with carboxymethyl cellulose, preferably spraying 2-5 times, stirring the probiotics after each spraying;

[0043] Step 2: Add the coating into the chitosan solution, shake and react, form a chitosan self-assembled layer on the surface of the coating through the electrostatic adsorption of carboxymethyl cellulose and chitosan, filter and dry to obtain the core material.

[0044] Preferably, steps 1 to 2 can be repeated 1-3 times to obtain 2-4 groups of self-assembled composite layers, and when the coating is added to the chitosan solution for the last time, sodium tripolyphosphate solution is slowly added to cross-link the outermost chitosan layer along with the oscillation reaction, and the mass ratio of sodium tripolyphosphate to the outermost chitosan layer is 1: (40-60).

[0045] Sodium tripolyphosphate molecules contain multiple negatively charged phosphate ions, while chitosan molecules have multiple amino cations and hydroxyl groups. The phosphate ions and amino cations interact electrostatically, forming a cross-linked structure between one phosphate ion and two or three amino cations, forming a cross-linked network of sodium tripolyphosphate and chitosan. The cross-linked chitosan and sodium tripolyphosphate product has excellent biocompatibility and biodegradability.

[0046] A second aspect of the present invention provides a method for preparing a high expansion rate algae dietary fiber sustained-release capsule, characterized in that it comprises the following steps:

[0047] S1. Preparation of core material:

[0048] S1.1. Prepare a 1-10 w / v% carboxymethyl cellulose aqueous solution and preheat the probiotics in a coating pan; spray the carboxymethyl cellulose aqueous solution onto the probiotics and dry them with hot air, alternating between spraying and hot air drying to obtain a coating coated with carboxymethyl cellulose;

[0049] S1.2, dissolving chitosan in an aqueous solution of acetic acid at a concentration of 1-2 wt% to obtain a chitosan solution at a concentration of 1-3 w / v%, adding the coating to the chitosan solution, shaking the reaction, filtering and drying to obtain the core material;

[0050] S2. Preparation of sustained-release capsules by negative pressure low-temperature spray drying:

[0051] S2.1 Add the wall material raw materials into 60-80℃ deionized water, stir to obtain a wall material solution, and cool to room temperature;

[0052] S2.2 Add the core material to the wall material solution and homogenize at high speed and / or under pressure;

[0053] S2.3 The material homogenized in step S2.2 is atomized in a negative pressure drying chamber while introducing dry gas. The vacuum degree in the drying chamber is -0.1 to -0.01 MPa, the air inlet temperature in the drying chamber is 30-45°C, and the air outlet temperature is 20-35°C.

[0054] Preferably, the wall material raw material further comprises carboxymethyl cellulose, and the amount thereof is 20-30% of the total mass of the algae dietary fiber and the resistant dextrin.

[0055] A third aspect of the present invention provides a use of the aforementioned high expansion rate algae dietary fiber sustained-release capsule in food and medicine.

[0056] The present invention has the advantages that:

[0057] (1) By adopting the process steps of pretreatment, enzymatic hydrolysis, acid-base treatment, activation treatment, freeze drying and low temperature crushing, a high-nutrition and high-activity algae dietary fiber with a particle size of 2-30 μm, preferably an average particle size D50 of 5-20 μm, and D10 of 2-8 μm, Dx represented by Dx=(D50-D10) / D50 is in the range of 0.4 or more and 0.8 or less, a narrow distribution range, a large powder specific surface area, and a swelling power greater than 100 mL / g, preferably greater than 120 mL / g, more preferably greater than 150 mL / g, and a water holding capacity greater than 10000%, preferably greater than 11000%, and more preferably greater than 12000%. In addition, resistant dextrin is also used in the wall material. The resistant dextrin will not be digested and absorbed in the digestive tract, further enhancing the feeling of fullness, and then enters the intestine. The resistant dextrin itself also plays a role in the intestine as a dietary fiber.

[0058] (2) By utilizing the self-assembly properties of chitosan and carboxymethyl cellulose, a carboxymethyl cellulose coating layer is formed on the outside of the probiotics, and chitosan is further coated on the outside of the carboxymethyl cellulose. Alternating layers of the two can be formed as needed to provide stable and long-lasting protection for the probiotics. In addition, after adding the carboxymethyl cellulose component to the wall material, during the process of the wall material coating the core material, the electrostatic effect of the carboxymethyl cellulose and chitosan is more conducive to driving the dietary fiber to surround the core material. The beneficial ingredients of the sustained-release capsule of the present invention are diverse, including composite dietary fiber, probiotics that are beneficial to intestinal health, and other material combinations. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a schematic structural diagram of the high expansion rate algae dietary fiber sustained-release capsule of the present invention;

[0060] Figure 2 2 are the satiety curves of the examples and comparative examples.

[0061] Explanation of reference numerals: 1. core material, 2. carboxymethyl cellulose layer, 3. chitosan layer, 4. wall material. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below. Unless otherwise specified, the reagents used in the specific embodiments and examples are all commercially available.

[0063] A high expansion rate algae dietary fiber sustained-release capsule, which can be used in multiple fields such as food and medicine, comprises a core material 1 and a wall material 4, wherein the mass ratio of the core material 1 to the wall material 4 is 1:(1-3);

[0064] (1) Core material 1, in parts by mass, comprises the following components:

[0065] 15-25 servings of probiotics

[0066] 5-15 parts of carboxymethyl cellulose

[0067] 5-10 parts of chitosan;

[0068] The probiotics are selected from at least one of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium, Lactobacillus brevis, and Lactobacillus plantarum, and the number of viable probiotics is ≥5×10 9 CFU / ml.

[0069] The core material 1 forms a self-assembled coating layer (2, 3) on the surface of the probiotics through the electrostatic adsorption of carboxymethyl cellulose and chitosan, see the attached Figure 1The self-assembled coating layer includes a carboxymethyl cellulose layer 2 and a chitosan layer 3, and the two layers can continue to be alternately thickened, for example, to form 2-4 groups or more self-assembled composite layers, but the outermost layer is preferably the chitosan layer 3, which is beneficial for the subsequent intestinal targeting and improves the bonding effect with the wall material;

[0070] (2) Wall material 4, in parts by mass, comprises the following components:

[0071] 20-30 servings of algae dietary fiber

[0072] 10-20 parts of resistant dextrin

[0073] The optional carboxymethyl cellulose is used in an amount of 20-30% of the total mass of the algae dietary fiber and the resistant dextrin. The use of carboxymethyl cellulose in the wall material is conducive to better electrostatic bonding between the wall material 4 and the outermost chitosan layer 3 of the core material 1.

[0074] The algae dietary fiber has a swelling capacity greater than 100 mL / g, preferably greater than 120 mL / g, more preferably greater than 150 mL / g; and a water holding capacity greater than 10,000%, preferably greater than 11,000%.

[0075] The preparation method of the high expansion rate algae dietary fiber sustained-release capsule of the present invention comprises the following steps:

[0076] S1. Preparation of core material 1:

[0077] S1.1. Prepare a carboxymethyl cellulose aqueous solution with a concentration of 1-10 w / v%, preheat the probiotics in a coating pan at a temperature of 30-40°C and a rotation speed of 10-40 r / min; spray the carboxymethyl cellulose aqueous solution onto the probiotics at a spraying pressure of 1-5 kg / cm 2 , hot air drying at 35-50°C, spraying and hot air drying are performed alternately to obtain a coating coated with a carboxymethyl cellulose layer 2;

[0078] S1.2, dissolving chitosan in an aqueous solution of acetic acid at a concentration of 1-2 wt% to obtain a chitosan solution at a concentration of 1-3 w / v%, adding the coating to the chitosan solution, shaking the reaction, filtering and drying to obtain a core material coated with a chitosan layer 3;

[0079] Among them, steps S1.1 to S1.2 can be repeated 1-3 times, and when the coating is added to the chitosan solution for the last time, sodium tripolyphosphate solution is slowly added during the oscillation reaction to slightly cross-link the outermost chitosan layer, and the mass ratio of sodium tripolyphosphate to the outermost chitosan layer is 1: (40-60).

[0080] S2, core material 1 and wall material 4 are used to prepare sustained-release capsules by negative pressure low-temperature spray drying:

[0081] S2.1 Add the wall material raw materials to 60-80°C deionized water, stir to obtain a wall material solution, and cool to room temperature; the wall material raw materials include algae dietary fiber and resistant dextrin, and optionally carboxymethyl cellulose, and the amount of carboxymethyl cellulose is 20-30% of the total mass of the algae dietary fiber and resistant dextrin; the order of addition is preferably to add the carboxymethyl cellulose first to dissolve, then add the algae dietary fiber and resistant dextrin, and stir to mix.

[0082] Wherein, the algae dietary fiber is prepared by the following steps:

[0083] (1) Pretreatment: soaking the algae raw material in water, washing it, crushing it, and mixing it with water to obtain algae paste;

[0084] (2) Enzymolysis: adding complex enzyme to the algae paste, enzymolyzing and cooling to obtain enzymolysis material; comprising:

[0085] (2.1) Add 1-5 w / v% yeast aqueous solution to the algae paste and maintain the temperature at 25-35°C for 2-5 hours;

[0086] (2.2) Add a cellulase aqueous solution, raise the temperature at a rate of 1-3°C / min, maintain the temperature at 50±2°C while stirring, and perform enzymatic hydrolysis for 1-2 hours; the cellulase dosage is 0.01-0.03% of the mass of the algae paste, and the cellulase activity is 80-120 U / g;

[0087] (2.3) Add protease aqueous solution and heat to 55±1°C at a rate of 0.5-1°C / min. Then, maintain the temperature at 50±2°C for enzymatic hydrolysis for 1-2 hours under stirring, and cool to 35±2°C; the amount of protease used is 0.1-0.3% of the mass of the algae sauce, and the protease activity is 1800-2200U / g.

[0088] (3) Acid-base treatment: add hydrochloric acid to the enzymatic hydrolysis material to adjust the pH to 2-4, filter and collect the residue; wash the residue to remove Cl - , after draining, add it to a sodium carbonate aqueous solution for reaction, cool it down and add hydrochloric acid to neutralize it to a pH of 6-7;

[0089] (4) Gelation treatment: adding calcium chloride solution to gel, filtering and collecting the residue, and washing to obtain a water-containing crude product;

[0090] (5) Deodorization: Add the crude product containing water to a yeast aqueous solution with a concentration of 1-6 w / v%, stir at 20-30°C for 20-60 min, centrifuge, wash, and filter to collect the deodorized residue;

[0091] (6) activating the deodorized filter residue with a sodium chloride solution to obtain an activated crude product;

[0092] (7) The activated crude product is freeze-dried, and the freezing temperature of freeze-drying is -60°C to -40°C, and the vacuum degree is 10 to 50 Pa, and the algae dietary fiber is crushed into 2-30 μm. Preferably, in the particle size distribution obtained by laser diffraction scattering method, the average particle size D50 is 5-20 μm, the particle size D10 with a cumulative frequency of 10% starting from the small particle size side is 2-8 μm, and Dx represented by Dx = (D50-D10) / D50 is in the range of greater than 0.4 and less than 0.8.

[0093] S2.2 Add the core material 1 to the wall material solution and homogenize at high speed and / or under pressure; wherein the speed of the high-speed homogenizer is 10,000-20,000 rpm and the time of high-speed homogenization is 1-3 minutes; the speed of the pressurized homogenizer is 8,000-15,000 rpm and the pressure is 40-50 MPa, and homogenize 1-3 times;

[0094] S2.3 The material homogenized in step S2.2 is atomized in a negative pressure drying chamber, and dry gas is introduced at the same time. The vacuum degree in the drying chamber is -0.1 to -0.01 MPa, the air inlet temperature of the drying chamber is 30-45°C, and the air outlet temperature is 20-35°C, to produce high expansion rate algae dietary fiber sustained-release capsules with a particle size of 50-500μm, preferably 100-300μm.

[0095] With respect to the preparation and performance testing of algae dietary fiber, the present invention provides Preparation Examples 1-3 and Comparative Examples 1-3; and selects algae dietary fiber with a high expansion rate to prepare sustained-release capsules, obtaining Examples 1-3 and Comparative Examples 1-2, to compare the relevant performance of the sustained-release capsules.

[0096] Preparation Example 1

[0097] This preparation example is about the preparation method of seaweed dietary fiber, comprising the following steps:

[0098] (1) Pretreatment: soaking the algae raw material in water, washing it, crushing it, and mixing it with water to obtain algae paste;

[0099] (2) Enzymolysis: adding complex enzyme to the algae paste, enzymolyzing and cooling to obtain enzymolysis material; specifically including:

[0100] (2.1) Add 3 w / v% yeast solution to the algae paste and maintain the temperature at 25°C for 3 h;

[0101] (2.2) Add cellulase aqueous solution, increase the temperature at a rate of 3°C / min, maintain the temperature at 50°C under stirring, and perform enzymatic hydrolysis for 1 hour; the cellulase dosage is 0.017% of the mass of the algae paste, and the cellulase activity is 100 U / g;

[0102] (2.3) Add protease aqueous solution and heat to 55°C at a rate of 1°C / min. Then, maintain the temperature at 50°C for enzymatic hydrolysis for 1 hour under stirring, and cool to 35°C; the amount of protease used is 0.15% of the mass of the algae paste, and the protease activity is 2000U / g.

[0103] (3) Acid-base treatment: add hydrochloric acid to the enzymatic hydrolysis material to adjust the pH to 3, filter and collect the residue; wash the residue to remove Cl - , after draining, add it into sodium carbonate aqueous solution to react, cool it down and add hydrochloric acid to neutralize it to pH 7;

[0104] (4) Gelation treatment: adding calcium chloride solution to gel, filtering and collecting the residue, and washing to obtain a water-containing crude product;

[0105] (5) Deodorization: Add the crude product containing water to a yeast aqueous solution with a concentration of 4 w / v%, stir at 25°C for 30 min, centrifuge, wash, and filter to collect the deodorized residue;

[0106] (6) activating the deodorized filter residue with a sodium chloride solution to obtain an activated crude product;

[0107] (7) The activated crude product was freeze-dried at -45°C and a vacuum of 40 Pa, and directly crushed at low temperature to obtain a particle size of D 50 Algae dietary fiber with a diameter of 18.6μm, a D10 of 5.8μm, and a Dx of approximately 0.69.

[0108] Preparation Example 2

[0109] This preparation example is about the preparation method of seaweed dietary fiber, comprising the following steps:

[0110] (1) Pretreatment: soaking the algae raw material in water, washing it, crushing it, and mixing it with water to obtain algae paste;

[0111] (2) Enzymolysis: adding complex enzyme to the algae paste, enzymolyzing and cooling to obtain enzymolysis material; specifically including:

[0112] (2.1) Add 3 w / v% yeast aqueous solution to the algae paste and maintain the temperature at 35°C for 2 h;

[0113] (2.2) Add cellulase aqueous solution, increase the temperature at a rate of 2°C / min, maintain the temperature at 50°C under stirring, and perform enzymatic hydrolysis for 2 h; the cellulase dosage is 0.017% of the mass of the algae paste, and the cellulase activity is 100 U / g;

[0114] (2.3) Add protease aqueous solution and heat to 55°C at a rate of 1°C / min. Then maintain the temperature at 50°C for enzymatic hydrolysis for 2 hours under stirring, and cool to 35°C; the amount of protease used is 0.15% of the mass of the algae paste, and the protease activity is 2000U / g.

[0115] (3) Acid-base treatment: add hydrochloric acid to the enzymatic hydrolysis material to adjust the pH to 3, filter and collect the residue; wash the residue to remove Cl - , after draining, add it into sodium carbonate aqueous solution to react, cool it down and add hydrochloric acid to neutralize it to pH 7;

[0116] (4) Gelation treatment: adding calcium chloride solution to gel, filtering and collecting the residue, and washing to obtain a water-containing crude product;

[0117] (5) Deodorization: Add the crude product containing water to a yeast aqueous solution with a concentration of 5 w / v%, stir at 25°C for 40 min, centrifuge, wash, and filter to collect the deodorized residue;

[0118] (6) activating the deodorized filter residue with a sodium chloride solution to obtain an activated crude product;

[0119] (7) The activated crude product was freeze-dried at -50°C and a vacuum of 30 Pa, and directly crushed at low temperature to obtain a particle size of D 50 Algae dietary fiber with a diameter of 8.6μm, a D10 of 4.7μm, and a Dx of approximately 0.45.

[0120] Preparation Example 3

[0121] This preparation example is about the preparation method of seaweed dietary fiber, comprising the following steps:

[0122] (1) Pretreatment: soaking the algae raw material in water, washing it, crushing it, and mixing it with water to obtain algae paste;

[0123] (2) Enzymolysis: adding complex enzyme to the algae paste, enzymolyzing and cooling to obtain enzymolysis material; specifically including:

[0124] (2.1) Add 5 w / v% yeast aqueous solution to the algae paste and maintain the temperature at 30°C for 4 h;

[0125] (2.2) Add cellulase aqueous solution, increase the temperature at a rate of 1.5°C / min, maintain the temperature at 50°C under stirring, and perform enzymatic hydrolysis for 1.5 hours; the cellulase dosage is 0.017% of the mass of the algae paste, and the cellulase activity is 100 U / g;

[0126] (2.3) Add protease aqueous solution and heat to 55°C at a rate of 0.5°C / min. Then, maintain the temperature at 50°C for enzymatic hydrolysis for 1.5 hours under stirring, and cool to 35°C; the amount of protease used is 0.15% of the mass of the algae paste, and the protease activity is 2000U / g.

[0127] (3) Acid-base treatment: add hydrochloric acid to the enzymatic hydrolysis material to adjust the pH to 3, filter and collect the residue; wash the residue to remove Cl-, drain and add it to a sodium carbonate aqueous solution for reaction, cool it down and add hydrochloric acid to neutralize it to pH 7;

[0128] (4) Gelation treatment: adding calcium chloride solution to gel, filtering and collecting the residue, and washing to obtain a water-containing crude product;

[0129] (5) Deodorization: Add the crude product containing water to a yeast aqueous solution with a concentration of 6 w / v%, stir at 25°C for 50 min, centrifuge, wash, and filter to collect the deodorized residue;

[0130] (6) activating the deodorized filter residue with a sodium chloride solution to obtain an activated crude product;

[0131] (7) The activated crude product was freeze-dried at -55°C and a vacuum of 20 Pa, and directly crushed at low temperature to obtain a particle size of D 50 Algae dietary fiber with a diameter of 12.2μm, a D10 of 5.1μm, and a Dx of approximately 0.58.

[0132] Comparative Example 1

[0133] The difference between this comparative example and preparation example 3 is that step (5) of removing the fishy smell is omitted, and the aqueous crude product obtained by the gelation treatment in step (4) is directly subjected to sodium chloride activation treatment, freeze-drying and low-temperature crushing.

[0134] Comparative Example 2

[0135] The difference between this comparative example and preparation example 3 is that the enzymatic hydrolysis process in step (2) is different, specifically including: adding a cellulase aqueous solution and a protease aqueous solution, heating at a rate of 3°C / min, maintaining the temperature at 50°C under stirring, enzymolysis for 2 hours, and cooling to 35°C; the amount of cellulase used is 0.017% of the mass of the algae paste, the cellulase activity is 100U / g, the amount of protease used is 0.15% of the mass of the algae paste, and the protease activity is 2000U / g.

[0136] Comparative Example 3

[0137] The difference between this comparative example and preparation example 3 is that the conventional drying and crushing method is used instead of step (7) to obtain a particle size D 50 Algae dietary fiber with a diameter of 33.6 μm, a D10 of 3.5 μm, and a Dx of approximately 0.90.

[0138] The yield, water holding capacity, swelling capacity and odor of the algae dietary fiber samples obtained in Preparation Examples 1-3 and Comparative Examples 1-3 were measured. The results are shown in Table 1.

[0139] Yield (%) = total dietary fiber content in sample / dry weight of seaweed × 100%

[0140] Water holding capacity (%) = (sample wet weight - sample dry weight) / sample dry weight × 100%

[0141] Swelling capacity (mL / g) = (volume of dietary fiber after water absorption and swelling - volume of dry powder sample) / dry weight of sample × 100%.

[0142] Table 1 Yield, water holding capacity, swelling capacity and odor test results of each sample

[0143] Yield / % Water holding capacity / % Expansion force / mL / g Odor score Preparation Example 1 47.98 11795 169 2 Preparation Example 2 48.46 11828 173 1 Preparation Example 3 49.38 12028 186 0 Comparative Example 1 47.94 9882 151 8 Comparative Example 2 45.46 6062 78 6 Comparative Example 3 42.75 5896 66 3

[0144] Comparison revealed that the samples of Preparation Examples 1-3, obtained using the complete preparation method of the present invention, performed well in terms of yield, water holding capacity, expansion capacity, and odor. In particular, the sample of Preparation Example 3 achieved near-complete deodorization, with a water holding capacity exceeding 12,000% and an expansion capacity exceeding 180 mL / g. This demonstrated excellent overall performance, broad market value, and high customer satisfaction. The algae dietary fiber sample of Preparation Example 3 was further used to prepare the high-expansion-rate algae dietary fiber sustained-release capsules of the present invention.

[0145] Example 1

[0146] The high expansion rate algae dietary fiber sustained-release capsule of this embodiment comprises a core material and a wall material, and the mass ratio of the core material to the wall material is 1:2;

[0147] (1) The core material, in parts by mass, comprises the following components:

[0148] 20 servings of probiotics

[0149] 10 parts of carboxymethyl cellulose

[0150] 8 parts of chitosan;

[0151] The probiotics are Streptococcus thermophilus and Lactobacillus bulgaricus mixed in a mass ratio of 1:1;

[0152] The core material forms a self-assembled coating layer on the surface of the probiotics through the electrostatic adsorption of carboxymethyl cellulose and chitosan. The self-assembled coating layer includes an inner carboxymethyl cellulose layer and an outer chitosan layer.

[0153] (2) Wall materials, in parts by mass, include the following components:

[0154] Preparation Example 3 Algae dietary fiber 25 parts

[0155] 15 parts of resistant dextrin.

[0156] The method for preparing the high expansion rate algae dietary fiber sustained-release capsules of this embodiment comprises the following steps:

[0157] S1. Preparation of core material:

[0158] S1.1. Prepare a 5 w / v% carboxymethyl cellulose aqueous solution, mix and preheat the probiotics in a coating pan; spray the carboxymethyl cellulose aqueous solution onto the probiotics, and dry with hot air at 35°C, alternating between spraying and hot air drying to obtain a coating layer coated with a carboxymethyl cellulose layer;

[0159] S1.2. Dissolve chitosan in 1 wt% acetic acid aqueous solution to obtain a 2 w / v% chitosan solution, add the coating to the chitosan solution, shake the reaction, slowly add sodium tripolyphosphate solution to lightly crosslink the outermost chitosan layer, the mass ratio of sodium tripolyphosphate to the outermost chitosan layer is 1:50, filter and dry to obtain a core material coated with a chitosan layer;

[0160] S2, core material and wall material are prepared into sustained-release capsules by negative pressure low-temperature spray drying method:

[0161] S2.1 Add the wall material raw materials to 70℃ deionized water, stir to obtain a wall material solution, and cool to room temperature;

[0162] S2.2 Add the core material to the wall material solution and homogenize at 15,000 rpm for 1 minute, then homogenize twice at 10,000 rpm and 45 MPa.

[0163] S2.3 The material homogenized in step S2.2 is atomized in a negative pressure drying chamber while introducing dry gas. The vacuum degree in the drying chamber is -0.05 MPa, the air inlet temperature in the drying chamber is 40°C, and the air outlet temperature is 30°C.

[0164] Example 2

[0165] The difference between this embodiment and embodiment 1 is that the wall material includes carboxymethyl cellulose. When preparing the wall material solution, all the wall material raw materials are added to deionized water and mixed. In parts by mass, the wall material includes the following components:

[0166] Preparation Example 3 Algae dietary fiber 25 parts

[0167] 15 parts of resistant dextrin

[0168] 10 parts of carboxymethyl cellulose.

[0169] Example 3

[0170] The difference between this embodiment and embodiment 2 is that the mass ratio of the core material to the wall material is 1:2.5, and the self-assembled coating of the core material includes two carboxymethyl cellulose layers and two chitosan layers alternately formed, with the outermost layer being the chitosan layer. The preparation of the core material includes the following steps:

[0171] (1) preparing a carboxymethyl cellulose aqueous solution with a concentration of 5 w / v%, mixing and preheating the probiotics in a coating pan; spraying the carboxymethyl cellulose aqueous solution onto the probiotics, and drying with hot air at 35° C., alternately spraying and hot air drying to obtain a coating coated with a carboxymethyl cellulose layer;

[0172] (2) dissolving chitosan in an acetic acid aqueous solution having a concentration of 1 wt% to obtain a chitosan solution having a concentration of 2 w / v%, adding the coating to the chitosan solution, shaking the reaction, filtering and drying to obtain a coating coated with a chitosan layer;

[0173] (3) preheating the coating obtained in step (2) in a coating pan again; spraying with a carboxymethyl cellulose aqueous solution, and drying with hot air at 35° C., alternating between spraying and hot air drying, to obtain a coating having two carboxymethyl cellulose layers;

[0174] (4) The coating obtained in step (3) was added to the chitosan solution, shaken for reaction, and sodium tripolyphosphate solution was slowly added to slightly crosslink the outermost chitosan layer. The mass ratio of sodium tripolyphosphate to the outermost chitosan layer was 1:50. The core material was filtered and dried to obtain a core material alternately coated with two carboxymethyl cellulose layers and two chitosan layers. Figure 1 .

[0175] Comparative Example 1

[0176] The difference between this comparative example and Example 3 is that probiotics are used directly in the core material without forming a self-assembled coating layer. The mass ratio of the core material to the wall material is 1:2.5;

[0177] (1) a core material, wherein the core material includes probiotics, which are a mixture of thermophilic Streptococcus and bulgaricus Lactobacillus at a mass ratio of 1:1;

[0178] (2) Wall materials, in parts by mass, include the following components:

[0179] Preparation Example 3 Algae dietary fiber 25 parts

[0180] 15 parts of resistant dextrin

[0181] 10 parts of carboxymethyl cellulose.

[0182] The preparation method of the comparative example sample comprises the following steps:

[0183] (1) Add the wall material raw materials into 70°C deionized water, stir to obtain a wall material solution, and cool to room temperature;

[0184] (2) Add the probiotic core material to the wall material solution and homogenize at a high speed of 10,000 rpm for 1 minute, and then homogenize twice at a pressure of 10,000 rpm and 45 MPa;

[0185] (3) The homogenized material is atomized in a negative pressure drying chamber, and dry gas is introduced at the same time. The vacuum degree in the drying chamber is -0.05 MPa, the air inlet temperature of the drying chamber is 40°C, and the air outlet temperature is 30°C.

[0186] Comparative Example 2

[0187] The difference between this comparative example and Example 3 is that the algae dietary fiber of Preparation Example 3 is not used, and the wall material only includes 15 parts of resistant dextrin and 3.5 parts of carboxymethyl cellulose in parts by mass.

[0188] The following tests were performed on Examples 1-3 and Comparative Examples 1-2:

[0189] 1. Satiety test

[0190] Ten subjects were selected to test the above samples and glucose samples with equivalent calories. The data were recorded for a total of 3 hours. During the first hour, the data were recorded every 15 minutes. During the second and third hours, the data were recorded every 30 minutes. The average value was taken to draw the satiety curve. Figure 2 Based on the fasting or empty stomach state, where:

[0191] “-1”: extremely hungry;

[0192] “0”: hungry;

[0193] “1”: moderate hunger;

[0194] “2”: no feeling;

[0195] “3”: moderate satiety;

[0196] "4": full;

[0197] “5”: Extremely full.

[0198] Overall, the satiety provided by each sample varied significantly before 15 minutes, reaching a peak around 30 minutes before gradually declining. In comparison, Examples 1-3 and Comparative Example 1, which contain algal dietary fiber, demonstrated better overall satiety than Comparative Example 2 and the glucose group. Comparative Example 2, which contains resistant dextrin, also demonstrated better satiety than the glucose group. The samples of Examples 1-3 exhibited a relatively slow decline, providing a longer-lasting sense of fullness.

[0199] 2. Long-term stability test

[0200] 3 g of each sample and an untreated probiotic control were weighed, sealed with a cap, placed in an aluminum bag, and stored in a 4°C constant temperature laboratory box. Samples were taken after 90 days to measure the number of viable bacteria to obtain the bacterial survival rate and investigate the long-term stability. The results are shown in Table 2.

[0201] Table 2 Test results of long-term stable layer of each sample

[0202] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Control Example Survival rate / % 93.9 94.2 95.2 72.5 86.4 0.5

[0203] 3. Artificial gastric juice stability test

[0204] Prepare artificial gastric juice: take 16.4 ml of dilute hydrochloric acid with a concentration of about 10%, add about 800 ml of water and 10 g of pepsin, shake well and dilute with water to 1000 ml.

[0205] 1 g of each sample was placed in artificial gastric fluid and cultured in a shaker at 37°C and 180 rpm. Samples were taken after 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h and 3 h of treatment to neutralize the sample. The number of viable bacteria was determined and the survival rate was calculated. The stability of each sample under artificial gastric fluid conditions was analyzed based on the survival rate. The results are shown in Table 3.

[0206] Table 3 Stability test results of each sample in artificial gastric juice

[0207]

[0208]

[0209] Examples 1-3 and Comparative Example 2 have chitosan coatings that are relatively resistant to gastric acid breakdown, resulting in limited gastric release. Based on the approximately three-hour retention time of food, these samples demonstrate good probiotic protection in the stomach. The probiotic core material of Comparative Example 1 lacks the protection of a self-assembled coating, resulting in faster release at the low pH of gastric acid, significantly reducing probiotic survival.

[0210] 4. Perform small intestinal fluid release, colon simulation release test and embedding efficiency calculation on Examples 1-3

[0211] Prepare artificial simulated small intestinal fluid: take 6.8g of potassium dihydrogen phosphate, add 500ml of water to dissolve, and adjust the pH value to 6.8 with 0.1mol / L sodium hydroxide solution; take another 10g of pancreatic enzyme, add appropriate amount of water to dissolve, mix the two liquids, and dilute with water to 1000ml.

[0212] Prepare colon simulation fluid: dissolve 0.0123 g chitosanase in 1 L of water and adjust the pH to 7.2.

[0213] 2.5 g of the samples of Examples 1-3 were placed in 30 mL of artificial simulated small intestinal fluid and colon simulated fluid, respectively, and cultured in a shaker at 37°C and 180 rpm. Samples were taken out after 1 h, 2 h, 3 h, and 6 h to determine the number of viable bacteria in the artificial small intestinal fluid and colon simulated fluid.

[0214] After each sample was completely disintegrated in the colon-simulating fluid, the number of viable bacteria in the fluid was measured, and the embedding efficiency was calculated according to the following formula. The above results are shown in Table 4.

[0215]

[0216] Table 4 Results of small intestinal fluid release, colon simulation release test and embedding efficiency of Examples 1-3

[0217]

[0218] The probiotics protected by the self-assembled coating are released relatively slowly in the small intestinal fluid, but can be rapidly enzymatically hydrolyzed by chitosanase. The release rate of probiotics is much higher than that of similar samples in the small intestinal fluid.

[0219] According to the above-mentioned tests on satiety, stomach and intestines, it can be seen that the wall material components of the present invention, which are a compound of algae dietary fiber and resistant dextrin, can form a good and lasting sense of satiety in the stomach, and after being protected by the self-assembled coating layer, the release rate of the probiotic components in the stomach and small intestine is relatively low, and they stably enter the colon to exert their effects. It can provide meal replacement products for users with needs such as weight loss and lipid reduction, and is beneficial to protecting the user's intestinal health, providing more scientific, safe and lasting health care effects.

[0220] The above introduces the preferred embodiments of the present invention, which is intended to make the spirit of the present invention clearer and easier to understand, and is not intended to limit the present invention. Any modifications, replacements, and improvements made within the spirit and principles of the present invention should be included in the scope of protection outlined by the claims attached to the present invention.

Claims

1. A high expansion rate algae dietary fiber sustained-release capsule, characterized in that: Including core material and wall material, the mass ratio of core material to wall material is 1:(1-3); The core material includes the following components in parts by mass: 15-25 servings of probiotics 5-15 parts of carboxymethyl cellulose 5-10 parts of chitosan; Wall materials include the following components: 20-30 servings of algae dietary fiber 10-20 parts of resistant dextrin; The core material forms a self-assembled coating layer on the surface of the probiotics through the electrostatic adsorption of carboxymethyl cellulose and chitosan; The algae dietary fiber is prepared by the following steps: (1) Pretreatment: soaking the algae raw material in water, washing it, crushing it, and adding water to mix it to obtain algae paste; (2) Enzymolysis: adding complex enzyme to the algae paste, enzymolyzing and cooling to obtain enzymolysis material; (3) Acid-base treatment: add hydrochloric acid to the enzymatic hydrolysis material to adjust the pH to 2-4, filter and collect the residue; wash the residue to remove Cl - , after draining, add it to a sodium carbonate aqueous solution for reaction, cool it down and add hydrochloric acid to neutralize it to a pH of 6-7; (4) Gelation treatment: adding calcium chloride solution to gel, filtering and collecting the residue, and washing to obtain a water-containing crude product; (5) Deodorization: Add the crude product containing water to a yeast aqueous solution with a concentration of 1-6 w / v%, stir at 20-30°C for 20-60 min, centrifuge, wash, and filter to collect the deodorized residue; (6) activating the deodorized filter residue with a sodium chloride solution to obtain an activated crude product; (7) freeze-drying the activated crude product and crushing it at low temperature to obtain algae dietary fiber; In step (2), the enzymatic hydrolysis process of the complex enzyme includes: (2.1) Add yeast solution to algae paste and maintain the temperature at 25-35°C for 2-5 hours; (2.2) Add cellulase aqueous solution, increase the temperature at a rate of 1-3°C / min, maintain the temperature at 50±2°C while stirring, and perform enzymatic hydrolysis for 1-2 hours; (2.3) Add the protease aqueous solution and heat it to 55±1°C at a rate of 0.5-1°C / min. Then, maintain the temperature at 50±2°C for enzymatic hydrolysis for 1-2 hours while stirring, and then cool it to 35±2°C. The algae dietary fiber has a particle size D50 of 5-20 μm, a D10 of 2-8 μm, a Dx expressed as Dx=(D50-D10) / D50 within a range of 0.4 to 0.8, a swelling force greater than 150 mL / g, and a water holding capacity greater than 12000%. The core material and the wall material are prepared into the sustained-release capsule by a negative pressure low-temperature spray drying method.

2. The sustained-release capsule according to claim 1, wherein The probiotics are selected from at least one of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium, Lactobacillus brevis and Lactobacillus plantarum.

3. The sustained-release capsule according to claim 1, wherein The freezing temperature of freeze drying is -60°C to -40°C, the vacuum degree is 10 to 50 Pa, and the algae dietary fiber is crushed to 2-30 μm.

4. The sustained-release capsule according to any one of claims 1 to 3, wherein The core material is prepared by the following steps: Step 1: spraying a carboxymethyl cellulose aqueous solution onto the probiotics and drying with hot air to obtain a coating coated with carboxymethyl cellulose; Step 2: Add the coating to the chitosan solution, shake and react, form a self-assembled chitosan layer on the surface of the coating through the electrostatic adsorption of carboxymethyl cellulose and chitosan, filter and dry to obtain the core material.

5. The sustained-release capsule according to claim 4, wherein Steps 1 to 2 can be repeated 1-3 times, and When the coating is added to the chitosan solution for the last time, sodium tripolyphosphate solution is slowly added to cross-link the outermost chitosan layer during the oscillation reaction. The mass ratio of sodium tripolyphosphate to the outermost chitosan layer is 1:(40-60).

6. A method for preparing the high expansion rate algae dietary fiber sustained-release capsule according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Preparation of core material: S1.

1. Prepare a 1-10 w / v% carboxymethyl cellulose aqueous solution and preheat the probiotics in a coating pan; spray the carboxymethyl cellulose aqueous solution onto the probiotics and dry them with hot air, alternating between spraying and hot air drying to obtain a coating coated with carboxymethyl cellulose; S1.2, dissolving chitosan in an aqueous solution of acetic acid at a concentration of 1-2 wt% to obtain a chitosan solution at a concentration of 1-3 w / v%, adding the coating to the chitosan solution, shaking the reaction, filtering and drying to obtain the core material; S2. Preparation of sustained-release capsules by negative pressure low-temperature spray drying: S2.1 Add the wall material raw materials into 60-80℃ deionized water, stir to obtain a wall material solution, and cool to room temperature; S2.2 Add the core material to the wall material solution and homogenize at high speed or under pressure; S2.3 The material homogenized in step S2.2 is atomized in a negative pressure drying chamber while introducing dry gas. The vacuum degree in the drying chamber is -0.1 to -0.01 MPa, the air inlet temperature in the drying chamber is 30-45°C, and the air outlet temperature is 20-35°C.

7. The preparation method according to claim 6, wherein The wall material raw material also includes carboxymethyl cellulose, and the amount of carboxymethyl cellulose used is 20-30% of the total mass of the algae dietary fiber and the resistant dextrin.

8. Use of the high expansion rate algae dietary fiber sustained-release capsule according to any one of claims 1 to 5 in the preparation of food or medicine.

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