Efficient separation and preparation method of radix astragali seu hedysari extract

Abstract

The invention relates to the technical field of utilization of traditional Chinese medicinal materials, and discloses an efficient separation and preparation method of an astragalus extract, which comprises the following steps: carrying out supercritical extraction on raw materials, then carrying out water extraction, sequentially adding cellulase and papain in the water extraction process, carrying out enzymolysis treatment, centrifuging an astragalus extracting solution after the water extraction is finished, and collecting supernate to obtain the astragalus extract. And performing ultrafiltration by using ultrafiltration membranes with different molecular weights to obtain extracts with different molecular weights, and finally performing vacuum freeze drying. According to the invention, the extraction process is optimized, effective components are extracted, and the technology is simple in preparation method and wide in raw material source, can be used as raw materials of dietary therapy products, health foods and auxiliary and therapeutic drugs, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of utilization of traditional Chinese medicinal materials, and in particular to a method for efficiently separating and preparing an astragalus extract. Background Art

[0002] Astragalus is sweet and slightly warm. It has the effects of replenishing qi and strengthening the exterior, promoting diuresis and expelling toxins, draining pus, and healing sores and promoting tissue regeneration. It is a commonly used qi-replenishing medicine in clinical practice. Astragalus was first recorded in Shennong's Herbal Classic and was listed as a top-grade medicine. It is known as the "best qi-replenishing medicine". It has attracted much attention from experts and scholars at home and abroad due to its rich chemical components and powerful pharmacological effects. The main chemical components of Astragalus are polysaccharides, saponins, flavonoids, proteins, cellulose and trace elements. The content of polysaccharides in Astragalus is 48.8 mg / g, the content of total flavonoids in Astragalus is 47.4 mg / g, and the content of astragaloside saponins is relatively low, about 0.13-1.53 ​​mg / g. The flavonoid compounds isolated from Astragalus include flavonoids, isoflavones, isoflavanes and pteranodones. Among them, calycosin, 5-hydroxycalycosin and formononetin and their aglycones have significant effects in immune system regulation, anti-oxidation, anti-apoptosis and other aspects. One of the main active ingredients of astragaloside is astragaloside Ⅳ, which has the functions of regulating body metabolism and immune function.

[0003] At present, the extraction methods of Astragalus include water extraction, alcohol precipitation, enzymatic method, ultrasound and other methods. During the extraction process, the temperature is too high, which causes some heat-labile components to be destroyed and reduce the content and type of the extracted effective ingredients, or the addition of extraction agents (ethanol, methanol, methane, etc.). The application of the extract in food does not comply with national laws and regulations and poses a safety hazard. The scope of application of the industry is limited, which is not conducive to industrial production. Summary of the invention

[0004] The present invention aims to provide a highly efficient separation and preparation method of astragalus extract, so as to solve the problems of potential safety hazards and unsatisfactory extraction effect in the extraction process of astragalus functional components in the prior art.

[0005] To achieve the above purpose, the present invention adopts the following technical scheme: a highly efficient separation and preparation method of astragalus extract, wherein the raw material is subjected to supercritical extraction and then water extraction, cellulase and papain are added in sequence during the water extraction process for enzymatic hydrolysis, and then the extract is boiled and extracted; after the water extraction is completed, the astragalus extract is centrifuged, and the supernatant is collected, and then cyclic ultrafiltration is performed using ultrafiltration membranes with different molecular weights to obtain extracts with different molecular weights, and finally vacuum freeze-dried.

[0006] Preferably, as an improvement, the conditions of supercritical extraction are: extraction pressure 20-40MPa, temperature 20-60°C, separation kettle 1 temperature 20-60°C, separation kettle 1 pressure 5-15Mpa, separation kettle 2 temperature 10-40°C, separation kettle 2 pressure 1-6Mpa, and extraction time 0.5-5h.

[0007] In the present technical scheme, the pressure, temperature and extraction time in the extraction stage are the key factors affecting the extraction effect. When the extraction pressure increases, the movement speed of the solvent molecules increases, and the solubility of the extract in supercritical CO2 increases, so that the extraction rate continues to increase. However, when the extraction pressure increases to a certain extent, the CO2 density is too large, which affects the mass transfer efficiency of CO2, and the extraction capacity is reduced, while also increasing the cost of the equipment; increasing the extraction temperature helps to increase the fluidity of CO2, making it easier for volatile oils to dissolve, thereby improving the extraction rate; when the temperature is too high, the solubility of volatile oils in supercritical CO2 decreases, which in turn reduces the extraction rate; generally, as the extraction time increases, the extraction rate gradually increases. After the extraction rate reaches a peak value, the extraction time is further extended, and the extraction rate no longer increases, but CO2 is consumed, which increases the production cost; in addition, the extraction pressure, temperature and time do not act independently, but influence each other and act synergistically. The above parameter range is a better combination that has been verified by time.

[0008] Preferably, as an improvement, cellulase is first added during the water extraction process for enzymolysis, the material-liquid ratio in the system during enzymolysis is 1:5-1:15, the amount of cellulase added is 1-5%, the enzymolysis temperature is 30-60°C, and the enzymolysis time is 1-4h.

[0009] Preferably, as an improvement, after adding cellulase, papain is added to perform enzymatic protein removal, the amount of papain added is 1-5 U / g, the enzymatic hydrolysis temperature is 30-60° C., and the enzymatic hydrolysis time is 1-4 h.

[0010] Preferably, as an improvement, the cellulase is a liquid cellulase preparation obtained by immersion fermentation of a strain of Trichoderma reesei, and the papain is a pure natural bio-enzyme product extracted from the immature fruit of the papaya plant.

[0011] In this technical solution, the temperature of enzymolysis is a key factor affecting enzyme activity. Too high or too low a temperature will lead to enzyme inactivation. At the optimum temperature, the enzyme activity is the highest and the reaction rate is the fastest, which is conducive to improving the yield and purity of the product. In addition, too long a reaction time may lead to enzyme inactivation or excessive decomposition of the substrate, affecting the quality of the product.

[0012] Preferably, as an improvement, the residue is boiled and extracted after the enzymatic hydrolysis process is completed, and the boiling extraction time is 0.5-3h; water is added to the residue and the boiling extraction is continued for 0.5-3h under the condition of a solid-liquid ratio of 1:4-1:10, and the extraction is performed twice in total.

[0013] Preferably, as an improvement, after the water extraction is completed, the astragalus extract is centrifuged, and the centrifugation parameters are: 1000-6000rpm / min, 5-30min; the supernatants after two centrifugations are combined and the residue is discarded.

[0014] Preferably, as an improvement, when the supernatant after centrifugation is subjected to circulating ultrafiltration, the ultrafiltration temperature is 10-60°C, the pressure difference is 0.1-1.0 MPa, and the molecular weight of the ultrafiltration membrane is 1000-10000 Da.

[0015] In the present technical scheme, in the ultrafiltration stage, temperature is the key factor affecting the membrane concentration effect. For heat-sensitive substances, such as proteins, enzymes, vitamins, etc., higher concentration temperatures may cause them to be inactivated or degraded, affecting the quality and function of the product. In addition, the increase in temperature will cause the membrane channel to expand, thereby increasing the membrane efficiency, but too high a temperature can easily damage the membrane material (the material is modified polyethersulfone, which is not resistant to high temperatures). Controlling the temperature between 10-60°C will not easily inactivate the heat-sensitive components in the effective ingredients, but can ensure the flux of membrane separation, and will not cause damage to the membrane elements, thereby extending the service life of the membrane.

[0016] Preferably, as an improvement, the ultrafiltration process is to use ultrafiltration membranes with gradient molecular weights in sequence, and the molecular weight gradient is 10000Da and 1000Da in sequence.

[0017] Preferably, as an improvement, the conditions for vacuum freeze drying treatment are vacuum degree 1.3-13 Pa, pre-freezing temperature -50°C to -60°C, and drying time 20-40h.

[0018] The principles and advantages of this solution are: in actual application, in this technical solution, the target object - Astragalus has a low content of effective ingredients and a complex structure. Traditional extraction methods such as soaking and decoction have low extraction efficiency and are difficult to meet the needs of large-scale production. In addition, the high temperature during the extraction process destroys some thermally unstable components and reduces the content and type of effective ingredients extracted, resulting in poor extraction effect. In view of the problem of unsatisfactory extraction effect when extracting the functional components of Astragalus in the prior art, this solution optimizes the extraction process of the functional components of Astragalus. The method of full extraction of functional components and membrane separation is adopted to ensure the extraction effect of the functional components and the process safety of the entire extraction process. A combination of supercritical extraction and water extraction is adopted, and no entrainer is used in the extraction process. First, the raw material of Astragalus membranaceus is subjected to supercritical treatment, which can make its structure loose and form a loose porous structure. Under the action of ultra-high pressure, some intermolecular forces will be weakened or broken, prompting some macromolecular substances to become substances with smaller molecular weight after breaking bonds, making their gaps larger. At the same time, a cavitation effect is generated, causing some cells to break, and the effective ingredients in the cells to be freed, which greatly improves the dissolution of the effective ingredients. At the same time, fat substances can be completely extracted into the separation kettle 1, while saponins and flavonoids are extracted into the separation kettle 2. The process conditions during the extraction process are mild, and the effective ingredients of the obtained Astragalus membranaceus extract are not easily destroyed. After supercritical extraction, in the water extraction process, by adding cellulase, the cellulose is partially incompletely hydrolyzed and can be converted into polysaccharides, increasing the polysaccharide content; in the membrane concentration process, the final product of cellulose hydrolysis is glucose, which is permeated by a 1000 Dalton membrane, increasing the content of the effective ingredients in the concentrate. At the same time, cellulose is a component of the cell wall, and hydrolysis can destroy the cell wall, thereby dissolving the effective ingredients in the cell.

[0019] The above-mentioned extraction process can ensure the full dissolution of effective ingredients such as astragalus polysaccharides, astragalus flavonoids, and astragalus saponins. In addition, the inventors found in the research process that how to maintain its biological activity and effectively remove impurities during the extraction process is an important technical problem. This technology uses ultrafiltration technology to enrich the effective ingredients in the astragalus extract. According to the difference in the molecular weight of each effective component, macromolecules such as protein and cellulose are hydrolyzed into small molecules, and removed by membrane separation technology, which greatly retains the effective ingredients in the extract, and the separation and classification are clear. In addition, considering that the crude protein content in astragalus is 9.91% to 14.47%, the inventors have tried Sevage method, trichloroacetic acid method, trifluorotrichloroethane method, hydrochloric acid method, etc. to remove protein from polysaccharide liquid. The Sevage method has a high protein release rate and the lowest sugar loss rate, but the reagent chloroform used in this method is toxic. Trichloroacetic acid is an organic acid that reacts with the hydrophobic groups inside the protein to denature the protein and form a precipitate. However, excessive concentration of trichloroacetic acid will hydrolyze glycosidic bonds to a certain extent, destroy the polysaccharide structure, and reduce the yield of polysaccharides. This scheme adopts enzymatic treatment, using papain under specific conditions to achieve a high protein removal effect, and the protein is hydrolyzed into amino acids to pass through the membrane equipment. The selected enzymes are all insensitive to pH value, and there is no need to add acid and alkali to adjust the pH value to maintain enzyme activity. Under the premise of increasing the content of the target component, there is no need to add acid and alkali substances, and there is no need to adjust the pH value. In addition, when drying the filtrate, the vacuum freeze-drying method is used to freeze the water in the liquid medicine in advance, and then the frozen water in the liquid medicine is sublimated under a vacuum environment, which can better retain the original active ingredients of the medicinal materials. After vacuum freeze-drying, the Astragalus extract extract maintains the original chemical composition and physical properties, and removes more than 95% to 99% of the water, thereby achieving the purpose of drying. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flowchart of the process for the efficient separation and preparation of the astragalus extract according to an embodiment of the present invention.

[0021] Figure 2 This is a scanning electron micrograph of the raw medicinal material of Astragalus membranaceus in the examples of the present invention (control group and supercritical treatment group).

[0022] Figure 3 The scanning electron microscope image of the raw medicinal material powder of Astragalus membranaceus in the examples of the present invention (control group and supercritical treatment group). DETAILED DESCRIPTION

[0023] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0024] Example 1

[0025] A highly efficient separation and preparation method of an astragalus extract comprises the following steps:

[0026] Step 1: Pretreatment: Crush the tailings of the Astragalus slices for later use.

[0027] Step 2, supercritical extraction: the moisture content of the crushed astragalus is controlled at 6%, and placed in an extraction tank for supercritical extraction. The extraction conditions are: extraction pressure 35MPa, temperature 50°C, separation kettle 1 temperature 50°C, separation kettle 1 pressure 15Mpa, separation kettle 2 temperature 35°C, separation kettle 2 pressure 5.7Mpa, extraction time is 3h, and then the separated material is collected.

[0028] Step 3, enzymolysis: the material after supercritical extraction is first enzymolyzed by cellulase, which is a liquid cellulase preparation produced by the submerged fermentation process of the strain of Trichoderma reesei. During the enzymolysis, the material-liquid ratio in the system is 1:5, the amount of cellulase added is 1%, the enzymolysis temperature is 30°C, and the enzymolysis time is 4h.

[0029] Step 4, protein removal: after adding cellulase during the extraction process, add papain to remove protein by enzymatic method. The amount of papain added is 1U / g, the enzymatic hydrolysis temperature is 30-60°C, and the enzymatic hydrolysis time is 1-4h.

[0030] Step 5, boiling extraction: after the enzymatic hydrolysis process is completed, the enzyme is boiled to inactivate the enzyme, and boiling extraction is performed at the same time. The boiling extraction time is 0.5-3h. After the first boiling extraction, the filtered medicinal residue is continuously added with water and a second boiling extraction is performed at a solid-liquid ratio of 1:6. The extraction time is 0.5-3h (a total of 2 extractions).

[0031] Step 6, centrifugation: After the water extraction (boiling extraction) is completed, the astragalus extract is centrifuged, and the centrifugation parameters are: 16000rpm / min, 10min; then the supernatant is taken and the residue is discarded.

[0032] Step 7, membrane concentration: The supernatant after centrifugation is first subjected to cross-flow ultrafiltration using a spiral ultrafiltration membrane with a molecular weight cutoff of 10,000 Daltons at a temperature of 30°C and a pressure difference of 0.8 MPa, and then subjected to cross-flow ultrafiltration using a spiral ultrafiltration membrane with a molecular weight cutoff of 1,000 Daltons to obtain three components of a permeate with a molecular weight greater than 10,000 Daltons (such as polysaccharides, proteins, etc.), between 1,000 and 10,000 Daltons (such as flavonoids, astragaloside, etc.), and less than 1,000 Daltons, and the filtrate of each component is concentrated separately.

[0033] Step 8, drying: After the astragalus nanofiltrate is concentrated, vacuum freeze-drying is performed. The conditions for vacuum freeze-drying are: vacuum degree 1.3 Pa, pre-freezing temperature -50°C, and drying time 20h.

[0034] Example 2

[0035] The difference between this embodiment and embodiment 1 is that in step 3, the enzymatic hydrolysis stage, the solid-liquid ratio of the enzymatic hydrolysis system is 1:15; the addition amount of cellulase is 5%, the enzymatic hydrolysis temperature is 60° C., and the enzymatic hydrolysis time is 1 h; and the addition amount of protease is 5 U / g.

[0036] The conditions for vacuum freeze drying are: vacuum degree 13Pa, pre-freezing temperature -60°C, and drying time 40h.

[0037] Example 3

[0038] The difference between this embodiment and embodiment 1 is that in step 3, the enzymatic hydrolysis stage, the solid-liquid ratio of the enzymatic hydrolysis system is 1:10; the addition amount of cellulase is 3%, the enzymatic hydrolysis temperature is 45° C., and the enzymatic hydrolysis time is 3 h; and the addition amount of protease is 3 U / g.

[0039] The conditions for vacuum freeze drying are: vacuum degree 8Pa, pre-freezing temperature -55°C, and drying time 30h.

[0040] Experimental Example 1 Scanning electron microscope

[0041] The original Astragalus membranaceus (block and powder) without supercritical treatment (control group) and after supercritical treatment (treatment group) were subjected to scanning electron microscopy at 300, 500, 1000, and 2000 times. The results are as follows Figure 2-3 As shown in the figure: Astragalus raw materials (block, powder) without supercritical treatment (control group) and after supercritical treatment (treatment group) were subjected to scanning electron microscopy at 300, 500, 1000, and 2000 times. The results showed that the surface of the control group samples was flatter, tighter, smoother, more uniform, without impurities, regular in shape, dense in cross section, with fewer tiny holes and smaller gaps. The treatment group showed irregular shapes and shapes of different sizes, loose structure, rough surface, holes, and a loose porous structure has been formed, the pores and tube diameters have become larger, and the passages have become wider. After supercritical treatment, under the action of ultra-high pressure, some intermolecular forces will be weakened or broken, so that some macromolecular substances will become substances with smaller molecular weights after breaking bonds, making their gaps larger, greatly improving the extraction rate of effective ingredients.

[0042] Experimental Example 2

[0043] Using the same Astragalus as raw material, the following different methods were used to extract the effective components. The specific processing groups are as follows:

[0044] ① Astragalus water extraction method: weigh 1kg of Astragalus (powder), add 10 times water, heat to 55℃, add 1% cellulase and 2U / g papain in sequence, stir and keep warm for 2h, then boil and extract for 1h, centrifuge the extract (4000 rpm, 10min), add 8 times water to the residue and boil and extract for 1h, centrifuge the extract (4000 rpm, 10min), discard the residue, combine the two supernatants and concentrate at normal pressure and freeze-dry in vacuum.

[0045] ②Supercritical water extraction method: Weigh 1 kg of Astragalus (powder), treat it at an extraction temperature of 40°C and an extraction pressure of 30 MPa for 1 hour, and then extract, centrifuge, concentrate and vacuum freeze-dry the Astragalus according to the water extraction method.

[0046] ③Supercritical treatment ultrasonic extraction method: Weigh 1kg of Astragalus (powder), treat it at an extraction temperature of 40°C and an extraction pressure of 30MPa for 1h. For the first extraction, add 10 times of water, heat to 55°C, add 1% cellulase and 2U / g papain in sequence, stir and keep warm for 2h, then ultrasonically extract Astragalus, put it into the ultrasonic extraction equipment, the end of the ultrasonic horn is generally inserted into the liquid surface about 1-3cm, ultrasonic extraction is carried out for 60min under the conditions of ultrasonic opening 2-3s, interval 3-5s, and ultrasonic power 75%. After the extraction is completed, filter the retained liquid with a 200-mesh nylon filter bag, and then centrifuge (4000 rpm, 10min), and the residue is subjected to secondary extraction. For the second extraction, add 8 times of water, and ultrasonic extraction is carried out under the above conditions. The extract is centrifuged (4000 rpm, 10min), the residue is discarded, the supernatant is combined and concentrated at normal pressure, and vacuum freeze-dried.

[0047] ④Supercritical water extraction method: Weigh 1kg of Astragalus (powder), extract under the following conditions: extraction pressure 35MPa, temperature 50℃, separation kettle 1 temperature 50℃, separation kettle 1 pressure 15Mpa, separation kettle 2 temperature 35℃, separation kettle 2 pressure 5.7Mpa, extraction time 3h, and then collect the separated material. The material is further extracted, centrifuged, concentrated, and vacuum freeze-dried according to the water extraction method.

[0048] All four methods here use atmospheric pressure concentration in order to determine the best extraction method and pave the way for Experiment 3, in which the effective components are graded and separated by membrane concentration under the optimal conditions.

[0049] After 1 kg of Astragalus was extracted by the above method, its effective components, crude polysaccharides, total flavonoids and total saponins were tested. The test results are shown in Table 1.

[0050] Table 1 Test results of Astragalus membranaceus effective components (n=3)

[0051]

[0052] According to the test results, the yield of Astragalus membranaceus water extraction is low, and its yield is not significantly improved after supercritical treatment; after supercritical extraction and synergistic water extraction of this technical solution, its effective ingredients total flavonoids, total saponins, and crude polysaccharides are significantly higher than those of other extraction methods, so the best extraction method for Astragalus membranaceus is supercritical extraction water extraction.

[0053] In addition, the inventors also tried the water extraction and alcohol precipitation method and the water extraction and alcohol precipitation plus enzymatic hydrolysis method during the research and development period. The specific operations and test results are as follows:

[0054] Water extraction and alcohol precipitation method: 450g of Astragalus raw material (powder), add 4500g of water, boil and extract for 1h, centrifuge (4000 rpm, 10min), add 3800g of water to the residue and continue to boil and extract for 1h, centrifuge (4000 rpm, 10min), and discard the residue. Combine the two clear liquids and centrifuge. Concentrate the clear liquid to 500ml under normal pressure, pour it into 1000ml of 95% ethanol, stir vigorously and let it stand for 30min. Centrifuge (4700 rpm, 10min), and dry the residue at 65℃.

[0055] Water extraction, alcohol precipitation and enzymatic hydrolysis: 450g of Astragalus raw material (powder), add 4500g of water, heat to 55℃, add 4.5g of cellulase, stir and keep warm for 2h, boil and extract for 1h, centrifuge (4000 rpm, 10min). Add 3800g of water to the residue and continue to boil and extract for 1h, centrifuge (4000 rpm, 10min), and discard the residue. Combine the two clear liquids and centrifuge. Concentrate the supernatant to 500ml at normal pressure, pour into 1000ml of 95% ethanol, stir vigorously, and let it stand for 30min. Centrifuge (4000 rpm, 10min), and dry the residue at 65℃.

[0056] The results show that the above two methods need to be stirred continuously during the alcohol precipitation process, otherwise they will aggregate into agglomerates or form inclusion bodies, affecting the product quality. At the same time, the denaturation of alcohol causes partial or complete loss of its activity. The drying process is not easy to dry, and the drying time is long. After crushing, the sample contains organic residues, which is not conducive to sales. After comprehensive consideration of the difficulty of operation and extraction efficiency, the above two schemes are abandoned.

[0057] Experimental Example 3

[0058] Experimental Example 2 shows that the best extraction method for Astragalus is supercritical water extraction. The specific method is shown in Experimental Example 2. Weigh 1 kg of Astragalus raw material (powder) after supercritical extraction, add 10 times of water, heat to 55°C, add 1% cellulase and 2U / g papain in sequence, stir and keep warm for 2 hours, boil and extract for 1 hour, centrifuge the extract (4000 rpm, 10 min), continue to add 8 times of water to the residue and boil and extract for 1 hour, centrifuge the extract (4000 rpm, 10 min), discard the residue, combine the two supernatants and centrifuge the extract, and then concentrate with membranes of different molecular weights to obtain concentrates I (greater than 10000Da) and concentrates II (1000Da-10000Da) of different molecular weights, collect the membrane separation liquid (less than 1000Da), vacuum freeze-dry, weigh, and detect proteins, polysaccharides, total flavonoids, and total saponins.

[0059] Table 2 Test results of the effective components of membrane concentrate

[0060]

[0061] The test results show that after the astragalus extract is concentrated by membrane, the protein removal rate can reach about 90%. Polysaccharides can be enriched by a membrane with a molecular weight of 10,000 Da, flavonoids and astragaloside can be enriched by a membrane with a molecular weight of 1,000-10,000 Da, and the permeate less than 1,000 Daltons is mainly small molecules such as monosaccharides and amino acids (discarded), thereby achieving the purpose of separation and enrichment of the effective components of astragalus. Therefore, the method of this technical solution can not only achieve efficient extraction of functional components, but also effectively remove proteins, and simultaneously achieve enrichment and separation of functional components of different molecular weights.

[0062] Experimental Example 4

[0063] In addition, during the research and development stage, this technical solution explored the drying method of the astragalus extract. The specific processing method and experimental results are shown in Table 3:

[0064] Table 3

[0065]

[0066]

[0067] From the results of the drying experiment, it can be seen that the best drying method obtained in the experiment is vacuum freeze drying. The drying conditions are vacuum degree 1.3-13Pa, pre-freezing temperature -50℃~-60℃, out-of-box temperature 30℃, and time: 30h.

[0068] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A highly efficient separation and preparation method of astragalus extract, characterized in that: The raw materials are supercritically extracted and then water extracted. During the water extraction process, cellulase and papain are added in sequence for enzymatic hydrolysis, and then the extract is boiled and extracted. After the water extraction, the astragalus extract is centrifuged and the supernatant is collected. Then, ultrafiltration membranes with different molecular weights are used for cyclic ultrafiltration to obtain extracts with different molecular weights, and finally vacuum freeze-dried.

2. The method for efficiently separating and preparing an astragalus extract according to claim 1, characterized in that: The conditions of supercritical extraction are: extraction pressure 20-40MPa, temperature 20-60°C, separation kettle 1 temperature 20-60°C, separation kettle 1 pressure 5-15Mpa, separation kettle 2 temperature 10-40°C, separation kettle 2 pressure 1-6Mpa, and extraction time 0.5-5h.

3. The method for efficiently separating and preparing an astragalus extract according to claim 2, characterized in that: During the water extraction process, cellulase is first added for enzymolysis. During the enzymolysis, the material-liquid ratio in the system is 1:5-1:15, the amount of cellulase added is 1-5%, the enzymolysis temperature is 30-60°C, and the enzymolysis time is 1-4h.

4. The method for efficiently separating and preparing an astragalus extract according to claim 3, characterized in that: After adding cellulase, papain is added to perform enzymatic protein removal. The amount of papain added is 1-5 U / g, the enzymatic hydrolysis temperature is 30-60° C., and the enzymatic hydrolysis time is 1-4 hours.

5. The method for efficiently separating and preparing an astragalus extract according to claim 3 or 4, characterized in that: The cellulase is a liquid cellulase preparation obtained by immersion fermentation of a strain of Trichoderma reesei, and the papain is a pure natural bio-enzyme product extracted from immature fruits of papaya plants.

6. The method for efficiently separating and preparing an astragalus extract according to claim 5, characterized in that: After the enzymatic hydrolysis process is completed, the residue is boiled for extraction, and the boiling extraction time is 0.5-3h; water is added to the residue and the boiling extraction is continued for 0.5-3h under the condition of a solid-liquid ratio of 1:4-1:10, and the extraction is performed twice in total.

7. The method for efficiently separating and preparing an astragalus extract according to claim 6, characterized in that: After the water extraction is completed, the astragalus extract is centrifuged, and the centrifugation parameters are: 1000-6000rpm / min, 5-30min; the supernatants after two centrifugations are combined and the residue is discarded.

8. The method for efficiently separating and preparing an astragalus extract according to claim 7, characterized in that: When the supernatant after centrifugation is subjected to circulating ultrafiltration, the ultrafiltration temperature is 10-60°C, the pressure difference is 0.1-1.0MPa, and the molecular weight of the ultrafiltration membrane is 1000-10000Da.

9. The method for efficiently separating and preparing an astragalus extract according to claim 8, characterized in that: The ultrafiltration process is to use ultrafiltration membranes with gradient molecular weights for sequential ultrafiltration, wherein the molecular weight gradient is 10000Da and 1000Da for sequential ultrafiltration.

10. The method for efficiently separating and preparing an astragalus extract according to claim 9, characterized in that: The conditions of the vacuum freeze-drying treatment are as follows: vacuum degree 1.3-13 Pa, pre-freezing temperature -50°C to -60°C, and drying time 20-40h.

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