CN116786046A - A kind of instant microcapsule and its preparation method - Google Patents

Abstract

The invention provides a quick-dissolving microcapsule and a preparation method thereof. The preparation method of the microcapsules includes the following steps: 1) dry the emulsion using pressure spray to obtain tide powder; 2) the tide powder obtained in step 1) falls into the built-in fluidized bed and is processed by dry hot air to obtain the second The second-dried product; the processing time is 5-10 minutes; 3) Add the second-dried product obtained in step 2) into the vibrating fluidized bed, spray the binder through airflow in the granulation section, and then perform wet granulation; The spray amount of the adhesive is 2-3wt% of the total raw materials in the product; the emulsion includes a fat-soluble core material. The preparation method provided by the invention can obtain a loose grape-type product with excellent solubility. At the same time, the fine powder has good sensory properties because it has not been repeatedly dried.

Description

A kind of instant microcapsule and its preparation method

Technical field

The present invention relates to the technical field of microcapsules, and more specifically, to a quick-dissolving microcapsule and a preparation method thereof.

Background technique

Polyunsaturated fatty acid oils, such as arachidonic acid oil, docosahexaenoic acid oil, etc., have a wide range of biological functions in biological systems, can regulate the body's lipid metabolism and immunity, and have anti-cancer, prevention and treatment properties. The many functional characteristics of polyunsaturated fatty acids have been widely understood by consumers such as cardiovascular diseases, promoting body growth and development, and regulating gene expression. Arachidonic acid oil, docosahexaenoic acid oil, etc. are easily oxidized due to their own structure and produce unpleasant odors, and at the same time affect the function of the oil. Microcapsule technology is usually used to use packaging materials to treat arachidonic acid oil. , docosahexaenoic acid oil and other polyunsaturated fatty acid oils to protect it and improve its stability and flavor.

The current polyunsaturated fatty acid microcapsule products can show the same reconstitution properties as the overall materials in reconstituted products such as milk powder. However, with the diversified needs of end products and the expansion of application solutions, the current microcapsule products are relatively It is difficult to meet the application in products that require high dissolution speed, such as direct-drink powder and instant powder. Existing solutions to solve the problem of instant solubility of microencapsulated powders basically revolve around components, including adding hydrophilic colloids, compounding various oligosaccharides, replacing emulsifiers, etc., but few start from the preparation process. perspective research plan.

The microcapsule preparation process mainly includes material shearing, mixing, homogenization, spray drying and other processes. Among them, the drying section is one of the core processes for obtaining products of various shapes. It has the most critical control points, has a high impact on the core material, and is the most difficult to control.

In the existing technology, the spray methods in the spray drying section include pressure spray, centrifugal spray, air flow spray, etc. depending on the atomization mechanism. The difference mainly lies in the different power modes of the material liquid spraying. At the same time, the different atomization mechanisms cause the spray tower to The air inlet and outlet methods are also quite different. Among them, airflow spray consumes a lot of energy, and pressure spray has the advantages of high thermal efficiency, low maintenance cost and good product quality compared to centrifugal spray drying. The air inlet and outlet mode of the equipment is upper air inlet and upper air outlet. The main drying processes in spray drying include: the CN201010199030.1 secondary embedding process pioneered by the applicant, in which droplets are sprayed into the boiling drying device and wrapped by the powder bulging in the device; CN201310217380.X, CN201711419628.5, etc. The key point of the spray drying process in the literature is that the fine powder collected by the cyclone separator returns to the tower from the top of the tower to agglomerate, and the fine powder has been heated twice; freeze spray drying is to atomize the emulsion into droplets and spray it into a tank filled with freezing liquid. In the freezing chamber, the temperature of the frozen liquid is lower than the eutectic point of the emulsion; the frozen material is vacuum freeze-dried to obtain polyunsaturated fatty acid oil microcapsules. In addition, the optimization of spray drying methods in the existing technology mainly focuses on the concentration of the feed material, the pressure of the nozzle, the temperature of the inlet and outlet air, etc., and few new spray drying processes have been proposed.

Contents of the invention

The first object of the present invention is to provide a method for preparing microcapsules. The microcapsules obtained by using the preparation method have better instant dissolving effect and good sensory properties.

The preparation method of microcapsules provided by the invention includes the following steps:

1) Use pressure spray to dry the emulsion to obtain moist powder;

2) The tide powder obtained in step 1) falls into the built-in fluidized bed and is processed by dry hot air to obtain a secondary dried product; the processing time is 5-10 minutes;

3) Add the twice-dried product obtained in step 2) into the vibrating fluidized bed, spray the adhesive through airflow in the granulation section and then perform wet granulation; the spray amount of the adhesive is 1% of the total raw materials in the product. 2-3wt%;

The emulsion includes a fat-soluble core material.

In the existing technology, the conventional process uses a spray-tower agglomeration process. One process is that under air spray, the fine powder enters the built-in fluidized bed and adheres in an environment of 60-70°C for 1-5 hours. , using this process to prepare microcapsules containing fat-soluble core materials, is unfriendly to fat-soluble core materials, especially polyunsaturated fatty acids, and affects the senses; another process uses pressure spray, and the fine powder is returned to the tower at the top Agglomeration, although the agglomeration time is relatively shortened, the fine powder undergoes secondary heating, and the microcapsules obtained by this process are difficult to meet the instant requirements of direct drinking powder or other special fields.

In a preferred embodiment of the present invention, the fat-soluble core material includes easily oxidized substances, preferably polyunsaturated fatty acid oils, such as DHA oils, ARA oils, etc. In specific embodiments of the present invention, those skilled in the art can add common additives to the emulsion as needed, including but not limited to, emulsifiers, fillers, antioxidants, antagonists, pH adjusters, etc., and the emulsifiers can It is one or more of modified starch, sodium caseinate, whey protein, arabic gum, monoglycerides and diglycerides, and the filler can be one or more of maltodextrin, corn syrup, glucose, and lactose. Antioxidants can be ascorbic acid and its salts or derivatives, vitamin E, phospholipids, etc., and antagonists can be tricalcium phosphate and hydrogen calcium phosphate. Those skilled in the art can select the type and weight of additives to be added according to the needs of specific microcapsules.

The emulsion in the present invention can be prepared using preparation methods commonly used in this field. In the specific embodiment of the present invention, the preparation method of the emulsion includes adding the oil phase to the water phase and shearing to homogenize. The preparation method of the water phase includes mixing the powder (or microcapsule raw material components except the oil phase) with water and fully dissolving to obtain the water phase. Powders include the above-mentioned additives. The oil phase is a substance that is easily oxidized, such as polyunsaturated fatty acid oils.

Compared with the existing technology, the preparation method of microcapsules provided by the present invention uses pressure spray drying. After only processing for 5-10 minutes in a built-in fluidized bed, it is passed through a vibrating fluidized bed (also called an external fluidized bed). The adhesive with a specific concentration is sprayed by airflow, sprayed on the material and then wet and granulated. Using this preparation method, a loose agglomerated product can be obtained, and the obtained product has a better instant-dissolving effect. Moreover, although the agglomeration time is not long, due to the short high-temperature time experienced by the fat-soluble core material in the entire process, the quality of the microcapsule product can still be ensured and it has good sensory properties.

In a preferred embodiment of the present invention, the pressure spray in step 1) can be a multi-stage pressure spray. In a specific embodiment of the present invention, pressure spraying is performed in a pressure spray drying tower. That is, the emulsion is pumped into a pressure spray drying tower (pressure spray drying tower), dry hot air is introduced from the upper end of the pressure spray tower, and spray drying is performed to obtain moist powder. The dry hot air is discharged from the upper end of the pressure spray drying tower. In specific embodiments of the invention, the spray pressure may be 100-200 bar.

In the process flow given in the existing technologies such as CN201310217380. "The fine powder has been heated twice, and the product dissolution cannot directly meet the instant requirements of drinking powder or other special fields. In a specific embodiment of the present invention, the built-in fluidized bed in step 2) is arranged in a pressure spray drying tower. The built-in fluidized bed is usually located at the lower part of the pressure spray drying tower, so that the moist powder obtained in step 1) Fall into the built-in fluidized bed. When the wet powder obtained in step 1) falls into the built-in fluidized bed, dry hot air is passed into the built-in fluidized bed to further process the wet powder. The processing time is 5-10 minutes to obtain a secondary dry product. After treatment, the hot air here is discharged from the upper end of the pressure spray drying tower. In a preferred embodiment of the present invention, the upper air inlet temperature in the pressure spray drying tower is 140-200°C, and the upper air outlet temperature is 60-100°C. The inlet air temperature in the built-in fluidized bed can be 60-70°C.

In the present invention, the ejection amount of the adhesive that is air-sprayed in the vibrating fluidized bed is one of the core. If it is too high, the bed will collapse. If it is too low, the adhesion will be insufficient and the product will not agglomerate, affecting the instant dissolution. sex. In a preferred embodiment of the present invention, the binder can be one or more of water, a phospholipid solution, an aqueous solution containing an emulsifier, and the emulsion in step 1), wherein the solution can be selected as an emulsion or oil as required. Solution, in some specific applications, you can choose phospholipid oil solution or modified starch formula emulsion or protein formula emulsion obtained during the preparation of microcapsules, or it can also be an aqueous solution directly containing modified starch or protein. The content of the binder in the solution can be determined according to It needs to be adjusted according to the process requirements and will not be too limited here.

In a specific embodiment of the present invention, the vibrating fluidized bed can be arranged below the pressure spray drying tower, so that the secondary dried product obtained in step 2) falls into the vibrating fluidized bed. In a preferred embodiment of the present invention, an airflow spray device can be provided in the granulation section of the vibrating fluidized bed. The airflow spraying device is used to spray the adhesive on the vibrating fluidized bed through airflow to spray the secondary adhesive on the vibrating fluidized bed. The dried product is wet granulated. Among them, the inlet air temperature of the vibrating fluidized bed granulation section can be 60-70°C. It should be emphasized that although the inlet air temperature of this section is 60-70°C, this section is wetted under the condition of spray solution Adhesion, the core material suffers less thermal damage than conventional dry agglomeration. In a specific embodiment of the present invention, it also includes drying and/or cooling the product obtained by wet granulation to obtain a finished product. In the specific embodiment of the present invention, the vibrating fluidized bed can have both vibration and blowing functions, and drying and cooling can be achieved by controlling the temperature of the wind. The drying section time can be 5-15 minutes. Among them, the inlet air temperature of the drying section can be 45-55°C, and the inlet air temperature of the cooling section can be 15-25°C. In the specific embodiment of the present invention, the vibrating fluidized bed may include a granulation section, a drying section and a cooling section in sequence, and the three sections are continuous and performed simultaneously in the fluidized bed. In the vibrating fluidized bed section, dry hot air and cooling air are discharged from the upper end of the vibrating fluidized bed.

In a preferred embodiment of the present invention, the air discharged in step 1), step 2) and step 3) can also be separated and dusted to obtain fine powder, and the fine powder is combined with the secondary dried product obtained in step 2) At the same time, add it to the vibrating fluidized bed and proceed to step 3). This step and step 3) are performed continuously and simultaneously. The fine powder is reused to participate in subsequent granulation and bonding.

The microcapsules obtained using the above preparation method are microcapsules with a loose structure and have good instant dissolving effect, while the oil is still well embedded and protected. That is, another object of the present invention is to provide microcapsules obtained by the above preparation method.

Another object of the present invention is to provide a preparation system for microcapsules used in the above preparation method. The preparation system includes: a pressure spray drying tower, a vibrating fluidized bed, an airflow spray device and a cyclone separator;

The pressure spray drying tower is also equipped with a built-in fluidized bed. The moist powder obtained by pressure spray drying of the emulsion falls into the built-in fluidized bed and is treated with dry hot air for 5-10 minutes to obtain a secondary dried product;

The airflow spray device is used for wet granulating the secondary dried product on the vibrating fluidized bed by airflow spraying the binder;

The cyclone separator is used to separate fine powder in the air discharged from the pressure spray drying tower and the vibrating fluidized bed; the cyclone separator is connected to the vibrating fluidized bed through a pipeline to transport the fine powder to the vibrating fluidized bed.

In a preferred embodiment of the present invention, an air filtration system is further included for providing dry air to the pressure spray drying tower and the vibrating fluidized bed respectively. Air filtration systems include pumps and filtration devices that provide dry hot or cold air.

In a specific embodiment of the present invention, the vibrating fluidized bed may be disposed below the pressure spray drying tower, so that the secondary dried product falls into the vibrating fluidized bed. The vibrating fluidized bed may include a granulation section, a drying section and a cooling section. The product outlet of the pressure spray drying tower can be directly facing the granulation section of the vibrating fluidized bed. The airflow spray device is preferably arranged in the granulation section of the vibrating fluidized bed. The airflow spraying device can be movably connected to the vibrating fluidized bed. For example, the airflow spraying device can be inserted into the vibrating fluidized bed.

In the specific embodiment of the present invention, the cyclone separator can be provided with multi-stage cyclone separators according to actual needs. The cyclone separator is used to separate the fine powder in the air discharged from the pressure spray drying tower and the vibrating fluidized bed, and the tail gas is discharged after being dedusted by a water film.

In the specific embodiment of the present invention, a collecting device may also be included. The collecting device is used to collect the final product obtained from the vibrating fluidized bed. The collecting device may be located at the product outlet of the vibrating fluidized bed. For example, it may be located at the vibrating fluidized bed. Product outlet of the cooling section of the bed.

In a preferred embodiment of the present invention, as shown in Figure 1, the microcapsule preparation system includes a pressure spray drying tower 1, a vibrating fluidized bed 3, an air spray device 7, a cyclone separator 4, an air filtration system 6 and a collector. Material device 5. There is a built-in fluidized bed 2 in the pressure spray drying tower 1. The built-in fluidized bed 2 is located below the pressure spray drying tower 1. The built-in fluidized bed 2 is used to process the wet powder by drying hot air to obtain secondary Dry product. The hot dry air is introduced from the upper end of the pressure spray drying tower 1. After the treatment, the hot dry air is also discharged from the upper end of the pressure spray drying tower 1 (including the dry hot air that passes through the built-in fluidized bed 2 is also discharged from the upper end of the pressure spray drying tower 1 discharge). The vibrating fluidized bed 3 is arranged below the pressure drying tower 1 so that the secondary dried product falls into the vibrating fluidized bed 3 . At the same time, the dry hot air and cooling air are also discharged from the upper end of the vibrating fluidized bed 3. The airflow spray device 7 is inserted into the granulation section of the vibrating fluidized bed 3 and is used to wet-granulate the secondary dried product on the vibrating fluidized bed 3 by spraying the binder with airflow. The cyclone separator 4 is used to separate the fine powder in the air discharged from the pressure spray drying tower 1 and the vibrating fluidized bed 3. The cyclone separator 4 is connected to the vibrating fluidized bed 3 through a pipeline to transport the fine powder to the vibrating fluidized bed. On bed 3. Cyclone 4 includes a two-stage cyclone. The air filtration system 6 is used to provide dry air to the pressure spray drying tower 1 and the vibrating fluidized bed 3 respectively. The collecting device 5 is provided below the vibrating fluidized bed (cooling section) and is used to collect the finished microcapsules obtained from the vibrating fluidized bed 3 .

In a preferred embodiment of the present invention, as shown in Figure 1, the preparation method of microcapsules using the microcapsule preparation system includes the following steps:

Step 1: Pump the emulsion into the pressure spray drying tower 1 at high pressure, introduce dry hot air from the upper end of the pressure spray drying tower, perform spray drying to obtain dry moist powder, and discharge the dry hot air from the upper end of the pressure spray drying tower;

Step 2: The dry tidal powder obtained in step 1 falls into the built-in fluidized bed 2, and dry hot air is passed into the built-in fluidized bed to further dry and agglomerate to obtain a second-stage dry product. This process takes 5-10 minutes. , and discharge hot dry air from the upper end of the pressure spray drying tower 1;

Step 3: The second-stage dry product obtained in step 2 falls into the vibrating fluidized bed 3. In the granulation section, the adhesive is air-sprayed through the air-flow spray device 7 and then wet-granulated. After drying in the drying section and cooling in the cooling section, the finished product is obtained. , and discharge hot dry air and cooling air from the upper end of the vibrating fluidized bed 3, where the drying period is 5-15 minutes;

Step 4: Pass the air discharged in steps 1, 2 and 3 into the cyclone separator 4 (there is a two-stage separator in Figure 1, a primary cyclone separator and a secondary cyclone separator) for separation and dust removal. Fine powder is obtained, and the tail gas is discharged after dust removal by water film;

Step 5: Transport the fine powder collected in Step 4 to the vibrating fluidized bed 3 through a pipeline, mix it evenly with the second-stage drying product, and proceed to Step 3 (i.e., rewetting and granulating, and further drying and cooling to obtain the finished product).

Steps 3/4/5 are continuous and simultaneous processes.

The products prepared by the microcapsule preparation method provided by the present invention can avoid the fat-soluble core material from being dried at a secondary high temperature, which affects product quality, especially sensory, stability, etc. The microcapsule preparation method provided by the invention can obtain a loose agglomerated grape-type product, which has better instant dissolving effect and the product has good sensory properties.

Description of the drawings

Figure 1 shows the microcapsule preparation system provided in the examples and specific implementations; wherein, 1-pressure spray drying tower, 2-built-in fluidized bed, 3-vibrating fluidized bed, 4-cyclone separator, 5-collector Material device, 6-air filtration system (including pump, filter device), 7-air spray device.

Detailed ways

Specific implementations of the present invention will be described in further detail below with reference to examples. The following examples are used to illustrate the present invention, but are not used to limit the scope of the present invention.

Unless otherwise specified, "%" in the present invention refers to mass percentage.

The solubility test is as follows: add the sample into warm water at 45°C at a ratio of 6.5% and start timing. Measure the time it takes for the powder to completely sink below the liquid surface from contact with the liquid surface. This is the diffusion rate. Then use a glass rod to stir at a speed of 3 rpm for 15 seconds and then let it stand. Observe the surface and internal conditions of the solution and make a score. A score of "0" means that no obvious insoluble matter is observed; a score of "1" means that a small amount of insoluble matter can be observed; a score of "2" means that a moderate amount of insoluble matter can be observed; a score of "3" means that a lot of insoluble matter can be observed Insoluble material can be observed; a score of "4" indicates that a large amount of insoluble material can be observed.

The oral instant dissolution test is as follows: take 1g sample and record the time from when the sample is placed in the mouth to when there is no grainy feeling in the mouth.

Example 1

This embodiment provides a loose polyunsaturated fatty acid microcapsule. The preparation system is as shown in Figure 1. The preparation method includes the following steps:

The components of the microcapsule raw materials are: 6% sodium caseinate, 26% DHA oil, 4% sodium ascorbate, 1% monoglycerides and 63% solid corn syrup.

(1) Put sodium caseinate, monoglycerides, solid corn syrup, and sodium ascorbate into 70°C hot pure water in sequence, and fully shear and dissolve to obtain the water phase;

(2) Add DHA oil to the above water phase and shear it for 10 minutes at 10000r/min;

(3) The above emulsion is homogenized twice by a high-pressure homogenizer at 800 bar to obtain an emulsion with a solid content of 50%.

(4) High-pressure pump the emulsion into the pressure spray drying tower 1, introduce dry hot air from the upper end of the pressure spray drying tower 1, and perform spray drying. The spray pressure is 200bar to obtain dry moist powder, which is discharged from the upper end of the pressure spray drying tower. Dry hot air; the upper air inlet temperature in the tower is 180±2℃, and the upper air outlet temperature is 80±2℃.

(5) The first-stage dry moisture powder obtained in step (4) falls into the built-in fluidized bed 2, and dry hot air is passed into the built-in fluidized bed 2 for further drying and agglomeration to obtain the second-stage dried product. The process time It is 5 minutes, and the air inlet temperature of the built-in fluidized bed is 65±2℃.

(6) The second-stage dried product obtained in step (5) falls into the vibrating fluidized bed 3, and in the granulation section, the adhesive (the adhesive is water in this embodiment) is air-sprayed through the air-spray device 7, and then Wet granulation, the amount of sprayed water is 3% of the total raw materials of microcapsules, and then the finished product is obtained after drying in the drying section and cooling in the cooling section, and the dry hot air and cooling air are discharged from the upper end of the vibrating fluidized bed, in which drying (drying while Granulation) for 5 minutes; the air inlet temperature of the vibrating fluidized bed granulation section is 65±2℃, the air inlet temperature of the drying section is 50±2℃, and the air inlet temperature of the cooling section is 20℃.

(7) Pass the air discharged in steps (4), (5) and (6) into the cyclone separator 4, and separate and remove dust in the first-level cyclone separator and the second-level cyclone separator to obtain fine powder, The exhaust gas is discharged after dust removal by water film;

(8) Transport the fine powder collected in step (7) to the vibrating fluidized bed through the pipeline, mix it evenly with the second-stage drying product, and then wet and granulate it. After further drying and cooling, the finished product is obtained, and the finished product enters the aggregate device 5; Step (8) and step (6) are performed simultaneously and continuously.

The product indicators obtained in this example include DHA content of 10%, dissolution index of 0, instant dissolution time in the mouth of 1 s, surface oil of 0.3%, and no obvious fishy smell in the mouth.

Example 2

The preparation method and system of this example are the same as those of Example 1, with the following differences:

The components of the microcapsule raw materials in this embodiment are: 6% sodium caseinate, 26% DHA oil, 4% sodium ascorbate, 5% whey protein, and the remainder of solid corn syrup.

The solid content of the emulsion in step (3) is 40%.

In step (6), the adhesive is 10% sodium caseinate solution, and the spray amount is 3% of the total raw materials of the microcapsules.

The product indicators obtained in this example include DHA content of 10%, dissolution index of 0, instant dissolution time in the mouth of 2 seconds, surface oil of 0.28%, and no obvious fishy smell in the mouth.

Comparative example 1

The preparation method and system of this comparative example are the same as those of Example 1, with the following differences:

The amount of adhesive sprayed in step (6) is 8% of the total raw materials of the microcapsules.

In this comparative example, there will be a bed collapse phenomenon, and a loose microcapsule product cannot be obtained.

Comparative example 2

The preparation method and system of this comparative example are the same as those of Example 1, with the following differences:

The amount of adhesive sprayed in step (6) is 1% of the total raw materials of the microcapsules.

The product in this comparative example has insufficient adhesion, and the insufficiently adhered powder is too fine and cannot be dispersed well during the dissolution test. The index is 3.

This comparative example also shows that powders that are not agglomerated or insufficiently bonded and granulated will affect their solubility due to problems such as excessive fineness and density.

Comparative example 3

This comparative example adopts the process flow described in the conventional air flow spray-tower agglomeration process. The difference between the process equipment and the present invention is that there is no external fluidized bed, the spray equipment is an air flow spray tower, and the cyclone separator is connected to the inside of the tower through a pipeline. Connected, agglomeration occurs in the built-in fluidized bed, and the fine powder returns to the tower through cyclone separation to participate in agglomeration. The agglomeration condition is that the built-in fluidized bed is adhered for 2 hours at 60-70°C to obtain microcapsules. The surface oil of the product is 0.42%, the dissolution index is 0, and the instant dissolution time in the mouth is 5 seconds. Although there is no obvious fishy smell in the odor sense, the product has a slight fishy smell after being directly ingested.

Comparative example 4

The difference between this comparative example and Comparative Example 3 is that the attempt was made to change the agglomeration time and reduce it to 0.5 hours, thereby improving the taste in the mouth. However, since spraying and adhesion are continuous processes, the reduction of adhesion time will lead to a reduction in the amount of emulsion spray, thus making the final The DHA content in the product cannot reach 10%. If you are trying to reduce time and ensure that the content reaches the standard, you must increase the proportion of polyunsaturated fatty acid oils such as ARA/DHA in the emulsion. You must also increase the proportion of emulsifier without reducing the concentration. Therefore, the viscosity of the emulsion will increase, thus affecting the delivery of the emulsion. , homogenization and atomization, which ultimately affects product quality, and the improvement and optimization process is too complicated.

Comparative example 5

Using the process equipment and process flow described in CN201310217380. , not suitable for use in some end products that require higher instant solubility. However, further reducing the agglomeration time will cause the problem of Comparative Example 4.

Comparative example 6

The difference between this comparative example and Example 1 is that an attempt was made to replace the pressure spray with centrifugal spray. However, due to the different exhaust modes of centrifugal spray and pressure spray, centrifugal spray is bottom exhaust, and the process requires all powder materials to be introduced into the cyclone separator. Then it falls into the vibrating fluidized bed. Not only is it difficult to modify the equipment, but the re-granulated product obtained by this process cannot achieve good adhesion and agglomeration due to the fine powder before entering the vibrating fluidized bed, which affects the final instant dissolution of the product. sex.

Finally, the method of the present invention is only a preferred embodiment and is not used to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A method for preparing microcapsules, comprising the steps of:

1) Drying the emulsion by using pressure spraying to obtain wet powder;

2) The wet powder obtained in the step 1) falls into a built-in fluidized bed and is treated by hot air for drying to obtain a secondary drying product; the treatment time is 5-10min;

3) Adding the product obtained in the step 2) into a vibrating fluidized bed, spraying an adhesive through air flow in a granulating section, and performing wet granulation; the sprayed amount of the adhesive is 2-3wt% of the total raw materials in the product;

the emulsion includes a fat-soluble core material therein.

2. The method of claim 1, wherein the binder is one or more of water, a phospholipid solution, an aqueous solution containing an emulsifier, and the emulsion of step 1).

3. The method of claim 1, wherein the fat-soluble core material comprises an oxidizable material, preferably polyunsaturated fatty acids.

4. A method according to any one of claims 1 to 3, wherein in step 2) the inlet air temperature in the internal fluidised bed is 60-70 ℃.

5. A method according to any one of claims 1 to 3, wherein in step 3) the inlet air temperature of the granulation section is 60-70 ℃; the air inlet temperature of the drying section in the vibrating fluidized bed is 45-55 ℃, and the air inlet temperature of the cooling section is 15-25 ℃.

6. A process according to any one of claims 1 to 3, characterized in that in step 3) the product obtained by wet granulation is dried by a drying section; the drying time is 5-15min.

7. A production method according to any one of claims 1 to 3, further comprising: and (3) separating and dedusting the air discharged in the steps (1), 2) and 3) to obtain fine powder, and adding the fine powder and the secondary dried product obtained in the step (2) into a vibrating fluidized bed simultaneously.

8. Microcapsules obtainable by the process according to any one of claims 1 to 7.

9. A system for preparing microcapsules, comprising: a pressure spray drying tower, a vibrating fluidized bed, an airflow spraying device and a cyclone separator;

the pressure spray drying tower is also provided with an internal fluidized bed, and damp powder obtained by pressure spray drying of emulsion falls into the internal fluidized bed and is subjected to drying hot air treatment for 5-15min to obtain a secondary dried product;

the airflow spraying device is used for carrying out wet granulation on the secondary dried product on the vibrating fluidized bed through airflow spraying adhesive;

the cyclone separator is used for separating fine powder in air discharged from the pressure spray drying tower and the vibrating fluidized bed; the cyclone separator is connected with the vibrating fluidized bed through a pipeline so as to convey the fine powder to the vibrating fluidized bed.

10. The microcapsule preparation system according to claim 9, further comprising an air filtration system for providing dry hot or cold air to the pressure spray drying tower and vibrating fluidized bed.