Extraction method of glycyrrhiza polysaccharide

Abstract

The invention discloses an extraction method of glycyrrhiza polysaccharide, and belongs to the technical field of extraction of plant active ingredients, the extraction method of glycyrrhiza polysaccharide is characterized by comprising the following steps: S1, adding glycyrrhiza powder into water, performing two-frequency-band ultrasonic extraction, and performing two-frequency-band ultrasonic alternate operation; s2, concentrating the water extract until the density of the concentrated solution is 1.15-1.20 g / mL, and stopping concentrating; s3, the concentrated solution is added into ethyl alcohol, alcohol precipitation, centrifugation and drying are conducted after uniform stirring, and the glycyrrhiza polysaccharide is obtained.According to the method, the purity and yield of a glycyrrhiza polysaccharide crude product are effectively improved by setting two-frequency-band auxiliary ultrasound in the water extraction process and controlling the concentration of the concentrated solution.

Description

Technical Field

[0001] The invention relates to the technical field of plant active ingredient extraction, in particular to a method for extracting liquorice polysaccharide. Background Art

[0002] In today's society, as people's attention to health and quality of life continues to grow, plant polysaccharides are increasingly sought after in the pharmaceutical and food industries due to their significant bioactivity and medicinal value. The diverse bioactivities and medicinal properties of plant polysaccharides provide new drug sources and therapeutic approaches for the pharmaceutical industry and open up new possibilities for the development of functional foods for the food industry. Licorice polysaccharides, one of the main active ingredients in licorice, have been widely used in numerous fields, including medicine, food, and aquaculture, due to their physiological activities in anti-tumor, immune-enhancing, and liver-protecting properties. This has led to increasing attention from researchers and related industries regarding the extraction and properties of licorice polysaccharides.

[0003] Currently, water extraction and alcohol precipitation are the most commonly used extraction methods for crude glycyrrhizic acid polysaccharides. This method is relatively simple to operate, does not require complex equipment and processes, and is relatively low-cost, offering advantages for large-scale production. The specific process typically involves mixing the licorice raw material with water. After soaking and heating for a period of time, the polysaccharides are dissolved in the water to form an aqueous extract. The aqueous extract is then concentrated through evaporation or other methods. Ethanol is then added to the concentrate to precipitate the polysaccharides, taking advantage of the solubility differences in the ethanol. Finally, the crude glycyrrhizic acid polysaccharides are obtained through centrifugation and drying. Other traditional extraction methods include acid-base extraction, which facilitates the dissolution and separation of polysaccharides by adjusting the pH of the solution, and enzymatic hydrolysis, which uses specific enzymes to break down structures such as cell walls to release the polysaccharides. These methods can also achieve varying degrees of success in extracting glycyrrhizic acid polysaccharides.

[0004] However, the existing water extraction and alcohol precipitation method has significant drawbacks. In practical applications, this method can result in a high concentration of impurities in the crude glycyrrhizic polysaccharide extracted. Furthermore, the alcohol precipitation process suffers from poor selectivity, failing to effectively separate the polysaccharide from other impurities, resulting in a low purity of the resulting polysaccharide. This low purity directly reduces its efficacy, making it difficult to directly apply to high-quality applications such as medicine and food, severely limiting the further development and utilization of glycyrrhizic polysaccharides. Summary of the Invention

[0005] In order to solve the problems in the prior art, the present invention provides a method for extracting glycyrrhiza polysaccharide, which effectively improves the purity and yield of the crude glycyrrhiza polysaccharide by setting two-band auxiliary ultrasound and controlling the concentration of the concentrated solution during the water extraction process.

[0006] The present invention provides a method for extracting glycyrrhiza polysaccharide using the following technical solution: A method for extracting liquorice polysaccharide comprises the following steps: S1. Adding licorice powder to water and performing two-band ultrasonic extraction, with the two-band ultrasonic extraction working alternately; S2. Concentrate the water extract until the density of the concentrate is 1.15-1.20 g / mL and stop concentrating; S3. Add the concentrated solution into ethanol, stir evenly, and then perform alcohol precipitation, centrifugation, and drying to obtain glycyrrhiza polysaccharide.

[0007] By adopting the above technical solution, when two-band ultrasound works alternately to extract licorice polysaccharides, the cell wall structure can be effectively torn apart and intracellular polysaccharides can be released. At the same time, when the two frequency bands act alternately, the oxidative degradation of polysaccharides can be effectively reduced, thereby improving the purity of licorice polysaccharides. In addition, the present application concentrates the water extract until the density of the concentrated liquid is 1.15-1.20 g / mL and stops concentrating, which helps to fully aggregate the polysaccharide molecules during the later alcohol precipitation. The density of the concentrated liquid is too high, the colloidal impurities are too high, and the uneven diffusion of ethanol leads to precipitate agglomeration, which reduces the purity of the polysaccharide.

[0008] As an example, the density of the concentrate can be 1.15 g / mL, 1.16 g / mL, 1.17 g / mL, 1.19 g / mL, 1.20 g / mL or a range of any two numbers. If the density of the concentrate is lower than 1.15 g / mL, the density of the concentrate is too low, the content of polysaccharides in the concentrate is low, and the intermolecular force is weak during subsequent alcohol precipitation, resulting in reduced purity. When the density of the concentrate is too high, excessive concentration leads to an increase in colloidal impurities, and the impurities co-precipitate with polysaccharides during alcohol precipitation, resulting in reduced purity of the polysaccharide.

[0009] Preferably, the ultrasonic extraction is performed 2-3 times, the single extraction time is 20-35 minutes, and the extraction temperature is 50-55°C.

[0010] Preferably, the two frequency bands of ultrasound in step S1 are low frequency and high frequency.

[0011] By adopting the above technical solution, licorice powder is added to water and extracted by alternating low-frequency and high-frequency ultrasonic extraction, which can improve the extraction efficiency and purity of polysaccharides and avoid the problems of traditional water extraction and alcohol precipitation methods such as high impurities and poor alcohol precipitation selectivity, resulting in low polysaccharide purity and reduced efficacy.

[0012] Preferably, the low frequency band is 35-45KHz, and the power is 80-90W / cm 2 The high frequency band is 200-300KHz, and the power is 5.5-6.0W / cm 2 .

[0013] As an example, the frequency of the low-frequency ultrasonic can be 35 KHz, 36 KHz, 37 KHz, 38 KHz, 39 KHz, 40 KHz, 41 KHz, 42 KHz, 43 KHz, 44 KHz, 45 KHz or a range value of any two numbers.

[0014] The frequency of the high-frequency ultrasonic can be 200 KHz, 210 KHz, 220 KHz, 230 KHz, 250 KHz, 270 KHz, 300 KHz or a range value of any two numbers, when the frequencies of the two ultrasonic are in this range, the dissolution rate of the polysaccharide in the licorice cell can be effectively improved, thereby improving the content and purity of the polysaccharide in the crude licorice polysaccharide.

[0015] By adopting the above technical solution, when the ultrasonic is selected as the low-frequency 35-45 KHz, the shock wave generated when the cavitation bubble collapses can efficiently tear the cell wall structure, when the low-frequency is less than 30 KHz, the shock wave generated by the cavitation bubble is too large and can damage the polysaccharide chain, when the low-frequency is higher than 50 KHz, the penetration depth of the shock wave generated by the cavitation bubble is insufficient, which has an impact on the breaking depth of the cell wall, thereby affecting the dissolution of the polysaccharide; when the high-frequency is selected as 200-300 KHz, the micro-cavitation bubble penetrates into the cell wall micropore to release the intracellular polysaccharide, the free radical yield of the ultrasonic in this frequency range is low, the oxidation degradation of the polysaccharide is reduced, the micro-flow effect enhances the diffusion of water molecules, and the solubility of the polysaccharide is improved, if the frequency of the high-frequency is too high, the heat generated by the high-frequency is intense, which leads to the gelatinization of the polysaccharide and reduces the purity and yield of the polysaccharide, therefore, in the present application, the licorice powder is added with water and then extracted by the two-frequency ultrasonic of the specific frequency and power alternately, which can improve the extraction efficiency of the polysaccharide; after the water extract is concentrated to a certain density, the ethanol is used for alcohol precipitation with a specific content, which can effectively reduce the impurities and improve the selectivity of alcohol precipitation, thereby improving the purity and efficacy of the licorice polysaccharide.

[0016] Preferably, the first 5 minutes of single extraction only uses low-frequency extraction, the last 5 minutes only uses high-frequency extraction, and the middle stage is low-frequency and high-frequency extraction alternately.

[0017] By adopting the above technical solution, different ultrasonic frequency bands are used in different time periods, which can more efficiently extract the polysaccharide from the licorice powder, for example, when the low-frequency ultrasonic is used in the first 5 minutes of extraction, the strong cell wall breaking can be realized, and when only the high-frequency ultrasonic is used in the last 5 minutes, the extraction system is more gentle, thereby dissolving more polysaccharide, improving the extraction efficiency and the purity of the polysaccharide, reducing the impurities, avoiding the problem of low polysaccharide purity caused by poor selectivity of alcohol precipitation, and improving the efficacy.

[0018] Preferably, the low-frequency and high-frequency work alternately at an interval of 0.5-1.0 seconds.

[0019] Preferably, the ethanol content in step S3 is 72-78%.

[0020] As an example, the ethanol content may be 72%, 73%, 74%, 75%, 76%, 77%, 78%, or any range of two numbers.

[0021] By adopting the above technical solution, a specific 72-78% ethanol content is used for alcohol precipitation during the extraction of glycyrrhiza polysaccharide, which can improve the selectivity of alcohol precipitation and reduce impurities, thereby improving the purity of glycyrrhiza polysaccharide and enhancing the efficacy, thereby overcoming the problems of poor alcohol precipitation selectivity, low polysaccharide purity and reduced efficacy of the existing water extraction and alcohol precipitation method.

[0022] Preferably, the particle size of the licorice powder is 60-80 mesh.

[0023] As an example, the particle size of the licorice powder can be 60 mesh, 65 mesh, 70 mesh, 75 mesh, 80 mesh, or a range of any two numbers.

[0024] By adopting the above technical solution, the particle size of the licorice powder is controlled at 60-80 mesh, which can increase the contact area between licorice and water, thereby improving the extraction efficiency of licorice polysaccharides, reducing the dissolution of impurities, and improving the purity of the extracted licorice polysaccharides.

[0025] Preferably, the material-liquid ratio in step S1 is 1:(5-8) g / mL.

[0026] By adopting the above technical solution, the material-liquid ratio is controlled within the range of 1: (5-8) g / mL, which enables the licorice powder to fully contact with water, is beneficial to the dissolution and diffusion of licorice polysaccharides in water, improves the extraction efficiency of licorice polysaccharides, reduces the dissolution of impurities, and thereby improves the purity of the extracted licorice polysaccharides.

[0027] In summary, the present invention has the following beneficial effects: the present application can effectively ensure the purity and yield of glycyrrhizic polysaccharides by adopting ultrasonic assistance during the extraction process and controlling the relative density of the concentrate within the range of 1.15-1.20 g / mL and the ethanol content during alcohol precipitation within the range of 72-78%, so that the yield of glycyrrhizic polysaccharides is between 12-15%, the content of polysaccharide components is above 65%, and the protein impurity content is lower than when the ethanol content is greater than 78%. Therefore, it can be seen that by controlling the above parameters, on the basis of ensuring impurity removal, the yield and purity of glycyrrhizic polysaccharides are also improved. Polysaccharide components only show immune activity when they have a certain molecular weight. The weight-average molecular weight of glycyrrhizic polysaccharides obtained by molecular weight detection of the finally obtained glycyrrhizic polysaccharides in the present application is 70,000-120,000 Daltons. The chromatographic column selected for detection is a TSK-4000 gel column, the mobile phase is a 0.7wt% sodium sulfate solution, and the flow rate is 0.5mL / L. DETAILED DESCRIPTION

[0028] The application will be further described in detail below in conjunction with examples. All reagents not specified by the manufacturer are conventional reagent products that can be obtained commercially.

[0029] In the present application, Ural licorice is selected, and the place of production is Inner Mongolia.

[0030] Example 1

[0031] A method for extracting licorice polysaccharides, comprising the following steps: S1, crushing licorice, sieving, and selecting licorice powder with a particle size of 60 mesh; S2, adding the licorice powder into water and simultaneously assisting ultrasonic extraction twice; The ultrasonic selection is two-frequency ultrasonic of low frequency and high frequency working alternately at an interval of 0.5 seconds, i.e. low-frequency working for 10 seconds, stopping for 0.5 seconds, high-frequency working for 10 seconds, and stopping for 0.5 seconds; The low frequency is 35 KHz, and the power is 80 W / cm 2 The high frequency is 200 KHz, and the power is 5.5 W / cm 2 The extraction temperature is 50℃, the first extraction duration is 35 min, the second extraction duration is 20 min, the low-frequency ultrasonic is used only for the first 5 min of each extraction, the high-frequency ultrasonic is used only for the last 5 min of each extraction, and the middle stage is the low-frequency and high-frequency ultrasonic working alternately, and the two extractions are mixed according to the solid-liquid ratio of 1:5 g / mL; S3, combining the water extracts obtained by multiple extractions and concentrating, and stopping the concentration when the density of the concentrated solution is 1.15 g / mL; S4, adding ethanol to the concentrated solution so that the content of ethanol in the concentrated solution is 72%, uniformly stirring, alcohol precipitation at 4℃ for 24 h, removing the supernatant, centrifuging the precipitate, and drying at 60℃ to obtain crude licorice polysaccharides.

[0032] Example 2

[0033] A method for extracting licorice polysaccharides, comprising the following steps: S1, crushing licorice, sieving, and selecting licorice powder with a particle size of 60 mesh; S2, adding the licorice powder into water and simultaneously assisting ultrasonic extraction twice; The ultrasonic selection is two-frequency ultrasonic of low frequency and high frequency working alternately at an interval of 1 second, i.e. low-frequency working for 10 seconds, stopping for 1 second, high-frequency working for 10 seconds, and stopping for 1 second; The low frequency is 40 KHz, and the power is 85 W / cm 2 The high frequency is 250 KHz, and the power is 6.0 W / cm 2The extraction temperature was 50°C, and the first and second extraction times were both 30 min. The first 5 min of each extraction used only low-frequency ultrasound, and the next 5 min used only high-frequency ultrasound. The middle stage was an alternating extraction of low-frequency and high-frequency ultrasound. Both extractions were mixed at a solid-liquid ratio of 1:8 g / mL. S3, combining the water extracts extracted multiple times and concentrating them until the density of the concentrated solution reaches 1.15 g / mL; S4. Add ethanol to the concentrate to make the ethanol content in the concentrate be 76%, stir evenly, and then precipitate with alcohol at 4°C for 24 hours. Remove the supernatant, centrifuge the precipitate, and dry at 60°C to obtain a crude glycyrrhizic polysaccharide.

[0034] Example 3

[0035] A method for extracting liquorice polysaccharide comprises the following steps: S1, crushing licorice, sieving, and selecting licorice powder with a particle size of 80 mesh; S2, adding licorice powder to water and performing extraction twice with the aid of ultrasound; Ultrasound was selected to work alternately at low and high frequency bands with an interval of 0.5 seconds, that is, low frequency worked for 10 seconds, stopped for 0.5 seconds, high frequency worked for 10 seconds, stopped for 0.5 seconds; The low frequency band is 45KHz and the power is 90W / cm 2 , high frequency band is 300KHz, power is 6.0W / cm 2 The extraction temperature was 55°C, and the first and second extraction times were both 35 min. The first 5 min of each extraction used only low-frequency ultrasound, and the next 5 min used only high-frequency ultrasound. The middle stage was an alternating extraction of low-frequency and high-frequency ultrasound. Both extractions were mixed at a material-liquid ratio of 1:8 g / mL. S3, combining the water extracts extracted multiple times and concentrating them until the density of the concentrated solution reaches 1.15 g / mL; S4. Add ethanol to the concentrate to make the ethanol content in the concentrate be 78%, stir evenly, and then precipitate with alcohol at 4°C for 24 hours. Remove the supernatant, centrifuge the precipitate, and dry at 60°C to obtain a crude glycyrrhizic polysaccharide.

[0036] Example 4

[0037] A method for extracting liquorice polysaccharide comprises the following steps: S1, crushing liquorice, sieving, and selecting liquorice powder with a particle size of 60 mesh; S2, adding licorice powder to water and performing ultrasonic extraction three times; The low-frequency and high-frequency ultrasonic waves are alternately operated at an interval of 1 second, i.e., the low-frequency ultrasonic wave is operated for 10 seconds, stopped for 1 second, the high-frequency ultrasonic wave is operated for 10 seconds, and stopped for 1 second. The low-frequency ultrasonic wave is 40 KHz and the power is 85 W / cm 2 The high-frequency ultrasonic wave is 250 KHz and the power is 6.0 W / cm 2 The extraction temperature is 50 DEG C, the first extraction time is 35 min, the second and third extraction times are both 20 min, the low-frequency ultrasonic wave is used for the first 5 min of each extraction, the high-frequency ultrasonic wave is used for the last 5 min of each extraction, and the low-frequency and high-frequency ultrasonic waves are alternately used in the middle stage; and the two extractions are both mixed according to a solid-liquid ratio of 1:8 g / mL. S3, the water extracts obtained through multiple extractions are combined and concentrated, and the concentration is stopped when the density of the concentrated solution is 1.15 g / mL; S4, ethanol is added into the concentrated solution to make the content of ethanol in the concentrated solution be 76%, and the concentrated solution is stirred uniformly and then alcohol precipitation is performed at 4 DEG C for 24 h, the supernatant is removed, the precipitate is centrifuged, and the crude glycyrrhiza polysaccharide is obtained by drying at 60 DEG C.

[0038] Example 5

[0039] An extraction method of glycyrrhiza polysaccharide, which is different from that of Example 2 in that, in step S3, the water extracts obtained through two extractions are combined and concentrated, and the concentration is stopped when the density of the concentrated solution is 1.17 g / mL, and the other steps are the same as those of Example 2.

[0040] Example 6

[0041] An extraction method of glycyrrhiza polysaccharide, which is different from that of Example 2 in that, in step S3, the water extracts obtained through two extractions are combined and concentrated, and the concentration is stopped when the density of the concentrated solution is 1.20 g / mL, and the other steps are the same as those of Example 2.

[0042] Comparative Example 1 An extraction method of glycyrrhiza polysaccharide, which is different from that of Example 2 in that, in step S3, the water extracts obtained through two extractions are combined and concentrated, and the concentration is stopped when the density of the concentrated solution is 1.25 g / mL, and the other steps are the same as those of Example 2.

[0043] Comparative Example 2 An extraction method of glycyrrhiza polysaccharide, which is different from that of Example 2 in that, in step S3, the water extracts obtained through two extractions are combined and concentrated, and the concentration is stopped when the density of the concentrated solution is 1.09 g / mL, and the other steps are the same as those of Example 2.

[0044] Comparative Example 3 An extraction method of glycyrrhiza polysaccharide, which is different from that of Example 2 in that, in step S2, only the ultrasonic wave with a frequency of 40 KHz and a power of 85 W / cm2 ultrasonic assisted extraction, and other operations are the same as those in Example 2.

[0045] Comparative Example 4 An extraction method of glycyrrhiza polysaccharide, which is different from Example 2 in that only ultrasonic with a frequency of 250 KHz and a power of 6.0 W / cm 2 ultrasonic assisted extraction, and other operations are the same as those in Example 2.

[0046] Comparative Example 5 An extraction method of glycyrrhiza polysaccharide, which is different from Example 2 in that no ultrasonic is used in step S1, and the specific water extraction process is as follows: the glycyrrhiza powder is mixed with water at a solid-liquid ratio of 1:8 g / mL, and then boiled for 0.5 h for the first time and 0.5 h for the second time, and the two water decoctions are mixed and concentrated, and other operations are the same as those in Example 2.

[0047] Comparative Example 6 An extraction method of glycyrrhiza polysaccharide, which is different from Example 2 in that the content of ethanol in the concentrated solution in step S4 is 81%, and other operations are the same as those in Example 2.

[0048] Comparative Example 7 An extraction method of glycyrrhiza polysaccharide, which is different from Example 2 in that the content of ethanol in the concentrated solution in step S4 is 65%, and other operations are the same as those in Example 2.

[0049] Extraction result detection Polysaccharide content determination: 100.00 mg of anhydrous glucose dried to a constant weight was precisely weighed, placed in a volumetric flask, dissolved with ultrapure water and diluted to 100 mL, and prepared into a 1 mg / mL glucose standard solution. The standard solution was gradiently diluted to 0.04, 0.06, 0.08, 0.10, 0.12 and 0.16 mg / mL, respectively. 1 mL of each gradient concentration of glucose solution was taken into a 10 mL brown volumetric flask, 1 mL of 5% phenol solution was added, shaken well, 5 mL of concentrated sulfuric acid was quickly added, shaken well, and then placed at room temperature for 30 min. The solution was diluted to 10 mL with ultrapure water, cooled to room temperature in an ice water bath, and the absorbance was measured at 490 nm using a UV spectrophotometer. The glucose concentration was taken as the abscissa and the absorbance was taken as the ordinate to draw a glucose standard curve. The regression equation of glucose concentration and absorbance within 0.04 mg / mL-0.16 mg / mL was Y=4.3371x+0.0127, and the correlation coefficient R 2 =0.9990.

[0050] The polysaccharide content in the crude glycyrrhizic polysaccharide was determined using the phenol-sulfuric acid method. 10 mg of the crude glycyrrhizic polysaccharide prepared by the present invention was pipetted into a 100 mL volumetric flask, 200 μL of a 5% phenol solution was added, and 1 mL of 98% concentrated sulfuric acid was quickly added after shaking. The mixture was allowed to stand for 5 minutes, heated in a 37°C water bath for 30 minutes, cooled to room temperature, and the absorbance was measured at a wavelength of 488 nm. The purity of the glycyrrhizic polysaccharide was calculated according to the formula. The calculation results are shown in Table 1.

[0051] Polysaccharide purity = measured polysaccharide concentration / theoretical polysaccharide concentration × 100%; Total polysaccharide yield = mass of purified polysaccharide / mass of crude licorice polysaccharide × 100%; Each group was tested three times and the average value was taken.

[0052] Table 1 Licorice polysaccharide purity test results project Licorice polysaccharide purity% Licorice polysaccharide yield% Example 1 64.6 13.6 Example 2 65.2 14.2 Example 3 65.1 13.8 Example 4 65.3 14.3 Example 5 67.7 14.8 Example 6 66.8 14.6 Comparative Example 1 58.3 14.5 Comparative Example 2 59.1 10.1 Comparative Example 3 56.4 9.3 Comparative Example 4 54.5 8.9 Comparative Example 5 52.3 8.6 Comparative Example 6 59.3 14.4 Comparative Example 7 64.9 12.3 As can be seen from Table 1: The purity of the crude glycyrrhiza polysaccharide obtained in Examples 1-3 of the present application is all above 64%, and the yield is above 13%, indicating that the crude glycyrrhiza polysaccharide obtained by the preparation method of the present application has a high purity.

[0053] Compared with Example 2, after the licorice powder was extracted three times, the polysaccharide purity and yield of the crude licorice polysaccharide were basically close to those in Example 2, indicating that the preparation method of the present application can obtain higher polysaccharide purity and yield by two extractions in advance.

[0054] Compared with Example 2, when the density of the concentrated solution was 1.17 g / L, the yield and purity of the crude glycyrrhizic acid polysaccharide obtained in Examples 5-6 were significantly increased compared with Example 2, but the purity and yield of the glycyrrhizic acid polysaccharide obtained in Example 5 were higher, indicating that when the density of the concentrated solution was 1.17 g / mL, the purity and yield of the polysaccharide could be optimized. Compared with Example 2, when the density of the concentrate is higher than 1.20 g / mL or lower than 1.15 g / mL, the purity of the crude licorice polysaccharide obtained in Comparative Examples 1-2 is reduced. The reason may be that when the density of the concentrate is too low, the polysaccharide concentration in the concentrate is low. When ethanol is subsequently added for alcohol precipitation, the intermolecular force of the polysaccharide is weakened, resulting in incomplete precipitation. When the density of the concentrate is high, excessive concentration leads to an increase in the concentration of colloidal impurities such as proteins and inorganic salts. These impurities co-precipitate with the polysaccharide during alcohol precipitation, increasing the total amount of precipitate, but the proportion of polysaccharide decreases. Therefore, the yield of Comparative Example 1 is increased, but the purity of the polysaccharide is significantly reduced.

[0055] Compared with Example 2, the purity and yield of glycyrrhiza polysaccharide obtained by Comparative Examples 3-5 are reduced when low-frequency ultrasound or high-frequency ultrasound is used or no ultrasound is used, which shows that when low-frequency and high-frequency ultrasound are used together, the plant cells of glycyrrhiza polysaccharide can be destroyed, and the cavitation bubbles generated by high-frequency ultrasound can enter the micropores of the cell wall to achieve effective release of intracellular polysaccharide.

[0056] Compared with Example 2, the purity of glycyrrhiza polysaccharide obtained by Comparative Example 6 is reduced, and the yield is slightly higher than that in Example 2 when the content of ethanol exceeds 72% to 78% defined in the application during alcohol precipitation, the purity of glycyrrhiza polysaccharide obtained by Comparative Example 7 is close to that in Example 2, but the yield is much lower than that in Example 2, which shows that the content of ethanol within the range defined in the application effectively improves the purity and yield of glycyrrhiza polysaccharide crude product.

[0057] The examples of the specific embodiment are the preferred examples of the application, but do not limit the protection scope of the application, so: any equivalent changes made according to the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A method for extracting licorice polysaccharide, characterized in that: The steps include: S1. Adding licorice powder to water and performing two-band ultrasonic extraction, with the two-band ultrasonic extraction working alternately; S2. Concentrate the water extract until the density of the concentrate is 1.15-1.20 g / mL and stop concentrating; S3. Add the concentrated solution into ethanol, stir evenly, and then perform alcohol precipitation, centrifugation, and drying to obtain glycyrrhiza polysaccharide.

2. The method for extracting glycyrrhiza polysaccharide according to claim 1, wherein: The ultrasonic extraction is performed 2-3 times, the single extraction time is 20-35 minutes, and the extraction temperature is 50-55°C.

3. The method for extracting glycyrrhiza polysaccharide according to claim 2, wherein: The two frequency bands of ultrasound in step S1 are low frequency and high frequency.

4. The method for extracting glycyrrhiza polysaccharide according to claim 3, wherein: The low frequency band is 35-45KHz, and the power is 80-90W / cm 2 The high frequency band is 200-300KHz, and the power is 5.5-6.0 W / cm 2 .

5. The method for extracting glycyrrhiza polysaccharide according to claim 4, wherein: The first 5 minutes of the single extraction only use low-frequency extraction, the next 5 minutes only use high-frequency extraction, and the middle stage is alternating low-frequency and high-frequency extraction.

6. The method for extracting glycyrrhiza polysaccharide according to claim 5, characterized in that: The low frequency and high frequency operate alternately at intervals of 0.5-1.0 seconds.

7. The method for extracting glycyrrhiza polysaccharide according to claim 1, wherein: The ethanol content in step S3 is 72-78%.

8. The method for extracting glycyrrhiza polysaccharide according to claim 1, wherein: The particle size of the liquorice powder is 60-80 meshes.

9. The method for extracting glycyrrhiza polysaccharide according to claim 1, wherein: The material-liquid ratio in step S1 is 1:(5-8) g / mL.