阅读说明：本技术 一种改进的甘草提取物的工艺 (Improved process for preparing liquorice root extract ) 是由 孙小鹦 廖萍 廖伟 廖忠 于 2020-12-29 设计创作，主要内容包括：本发明涉及一种改进的甘草提取物的工艺,所述工艺包括：取甘草用饱和的石灰水浸泡8-12小时后,过滤；取药渣用65-75％的乙醇作为提取溶剂,在60-80℃恒温下回流提取1-3次、每次2小时,过滤,合并滤液；合并浸泡滤液和回流提取滤液,减压浓缩至相对密度为1.15～1.25的稠膏、再低温真空带式干燥2h、粉碎得提取物。该工艺操作简单,生产成本低,周期短,干燥时间短,水分均匀、总黄酮含量高,质量稳定。(The invention relates to an improved process for preparing a licorice extract, which comprises the following steps: soaking Glycyrrhrizae radix in saturated lime water for 8-12 hr, and filtering; extracting the residue with 65-75% ethanol at 60-80 deg.C under reflux for 2 hr for 1-3 times, filtering, and mixing filtrates; and combining the soaking filtrate and the reflux extraction filtrate, concentrating under reduced pressure to obtain thick paste with the relative density of 1.15-1.25, performing low-temperature vacuum belt drying for 2 hours, and crushing to obtain the extract. The process has the advantages of simple operation, low production cost, short period, short drying time, uniform water content, high total flavone content, and stable quality.)

1. An improved process for the production of licorice extract, said process comprising the steps of: 1) soaking Glycyrrhrizae radix in saturated lime water for 8-12 hr, filtering, and collecting filtrate and residue; 2) taking 6-10 times of 65-75% ethanol as an extraction solvent, carrying out reflux extraction for 2 times at a constant temperature of 60-80 ℃, filtering, and combining filtrates; 3) mixing the filtrates obtained in the steps 1) and 2), concentrating under reduced pressure to obtain a thick paste with the relative density of 1.15-1.25, drying, and crushing to obtain the extract.

2. The process according to claim 1, characterized in that it comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 9-11 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 7-9 times of 68-72% ethanol as extraction solvent at 65-75 deg.C under reflux for 2 times, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.18-1.22, drying, and pulverizing to obtain extract.

3. The process according to claim 1, characterized in that it comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 8 times of 70% ethanol as extraction solvent at 70 deg.C under reflux for 2 times, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.20, drying, and pulverizing to obtain extract.

4. The process according to any one of claims 1 to 3, wherein the reflux extraction of step 2) is carried out 2 times for 1 to 3 hours each.

5. The process of claim 4, wherein the reflux extraction of step 2) is performed 2 times for 2 hours each.

6. The process according to any one of claims 1 to 3, wherein the drying in step 3) is low-temperature vacuum belt drying, and the specific conditions are as follows: the drying temperature is 100-150 ℃, the vacuum degree is-0.085 Mpa, the crawler speed is 150-190mm/min, the feed pump is 30-35Hz, and the crushing frequency is 30Hz-50 Hz.

7. The process according to claim 6, wherein the drying in step 3) is low-temperature vacuum belt drying, and the specific conditions are as follows: the drying temperature is 120 ℃, the vacuum degree is-0.085 Mpa, the track speed is 170mm/min, the feeding pump is 32Hz, and the crushing frequency is 40 Hz.

8. A process according to any one of claims 1 to 3, wherein the drying in step 3) is carried out for a period of from 1 to 3 hours.

9. The process of claim 8, wherein the drying in step 3) is carried out for a period of 2 hours.

10. The process according to claim 1, characterized in that it comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 70% ethanol at constant temperature of 70 deg.C under reflux for 2 times, each for 2 hr, filtering, and mixing filtrates; 3) mixing the filtrates obtained in the steps 1) and 2), concentrating under reduced pressure to obtain a thick paste with the relative density of 1.15-1.25, carrying out low-temperature vacuum belt drying for 2 hours, and crushing to obtain the extract.

Technical Field

The invention relates to the field of medicine extraction, in particular to an improved process for a liquorice extract.

Background

The liquorice is a plant with higher medicinal value, and is used in both Chinese and western medicine. From ancient Chinese wax, the Western medicine has used licorice as an expectorant, antitussive and sweet additive. In ancient Chinese pharmacology, Shen nong Ben Cao Jing, Licorice root is described as a drug for strengthening muscles and bones, increasing physical strength and treating wounds, and is listed as the top grade, which is called the king of the most popular herb and is rarely used in the menstruation. The Glycyrrhrizae radix contains various components such as saponins, triterpenes, flavonoids, coumarin, sterol, alkaloid, volatile oil, organic acid, amino acids, etc. The licorice has rich flavone components, and more than 300 licorice flavonoids compounds are reported at present. The licoflavone component comprises compounds such as flavonoid, flavanone, flavonol, isoflavone, chalcone and biflavone, and has high content of flavanone and chalcone. The flavanone compounds include liquiritin, liquiritigenin, neoliquiritin, liquiritigenin, etc., and the chalcone compounds include isoliquiritin, isoliquiritigenin, neoisoliquiritin, etc., especially the proportion of liquiritin is the largest. The licorice flavonoids have remarkable pharmacological activities of resisting ulcer, resisting tumor, resisting oxidation, inhibiting bacteria, resisting inflammation and the like, and are more and more concerned by people in recent years.

Application No. CN201911414265.5, a method for extracting licoflavone from Glycyrrhrizae radix. A method for extracting licoflavone from Glycyrrhrizae radix is disclosed. The method comprises the following steps: mixing a licorice medicinal material and an organic solvent according to a certain proportion, adding a pH regulator into a mixed system, controlling the pH value of the system to be less than or equal to 4, and performing multi-stage extraction on glycyrrhizic acid in the medicinal material; and (3) removing a part of non-flavonoid components from the first-grade extracting solution through alkali precipitation and filtration, wherein the filtrate is used for concentrating and enriching the licorice flavone components, and the subsequent-grade glycyrrhizic acid extracting solution can be continuously applied to the extraction of the licorice medicinal material in the next round/batch.

The technical scheme of CN201911414265.5 has the following problems: the extraction is divided into 1-6 grades, the process is complex, the cost is high, the large-scale production is difficult to realize, and the content of the total flavone is low.

Application No. CN201910133338.7 discloses that liquorice is used as a raw material, polar organic solvents are adopted for extraction, extract is filtered, filtrate is combined, the organic solvents are recovered from the filtrate under reduced pressure, vacuum concentration is carried out on the extract to obtain a liquorice crude extract, and the liquorice extract is prepared after the crude extract is treated by macroporous resin.

The technical scheme of CN201910133338.7 has the following problems: in the step, macroporous resin is used for eluting by distilled water, so that the cost is high; until the eluent is colorless in elution, impurity components such as protein, polysaccharide, inorganic salt and the like are removed for utilization, and the phenomenon that the elution is incomplete or the elution time is too long due to the colorless and difficult control of the elution standard can be caused; the drying method in the scheme adopts spray drying or freeze drying, and has the phenomena of high cost, long drying time, uneven sample drying and the like; the total flavone content is low.

Aiming at the problems, the inventor researches a process for extracting the extract from the liquorice through a series of tests, and the process has the advantages of simple operation, low cost, short period, high extraction content, short drying time and the like.

Disclosure of Invention

The invention aims to provide a process for improving a liquorice extract.

The process comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 8-12 hr, filtering, and collecting filtrate and residue; 2) taking 6-10 times of 65-75% ethanol as an extraction solvent, carrying out reflux extraction for 2 times at a constant temperature of 60-80 ℃, filtering, and combining filtrates; 3) mixing the filtrates obtained in the steps 1) and 2), concentrating under reduced pressure to obtain a thick paste with the relative density of 1.15-1.25, drying, and crushing to obtain the extract.

Preferably, the process of the invention comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 9-11 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 7-9 times of 68-72% ethanol as extraction solvent at 65-75 deg.C under reflux for 2 times, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.18-1.22, drying, and pulverizing to obtain extract.

Further preferably, the process of the present invention comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 8 times of 70% ethanol as extraction solvent at 70 deg.C under reflux for 2 times, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.20, drying, and pulverizing to obtain extract.

The reflux extraction in the step 2) of the invention is carried out for 2 times, and the time is 1 to 3 hours each time.

Preferably, the reflux extraction in step 2) of the present invention is performed 2 times, each time for 2 hours.

The drying in the step 3) of the invention is low-temperature vacuum belt drying, and the specific conditions are as follows: the drying temperature is 100-150 ℃, the vacuum degree is-0.085 Mpa, the crawler speed is 150-190mm/min, the feed pump is 30-35Hz, and the crushing frequency is 30Hz-50 Hz.

Preferably, the drying in step 3) of the present invention is low-temperature vacuum belt drying, and the specific conditions are as follows: the drying temperature is 120 ℃, the vacuum degree is-0.085 Mpa, the track speed is 170mm/min, the feeding pump is 32Hz, and the crushing frequency is 40 Hz.

The drying in the step 3) of the invention lasts for 1-3 h.

Preferably, the drying time in step 3) of the present invention is 2 hours.

The process comprises the following steps: 1) soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 70% ethanol at constant temperature of 70 deg.C under reflux for 2 times, each for 2 hr, filtering, and mixing filtrates; 3) mixing the filtrates obtained in the steps 1) and 2), concentrating under reduced pressure to obtain a thick paste with the relative density of 1.15-1.25, carrying out low-temperature vacuum belt drying for 2 hours, and crushing to obtain the extract.

Advantageous effects

1. According to the extraction process, the soaking solvent and the soaking time are considered in the soaking stage, the saturated lime water is used as the solvent, the liquorice is soaked for 10 hours and then filtered, the filtrate and the dregs are reserved, the saturated lime water is relatively safe and cheap, and the extract is high in total flavone content.

2. In the reflux extraction stage in the extraction process, the optimal scheme of reflux extraction is obtained through the investigation of parameters such as the amount of the extraction solvent, the time of the extraction solvent, the extraction times, the extraction temperature and the like, and the reasonability and the reliability of the extraction process are further proved.

3. The invention obtains the conditions of low-temperature vacuum belt type drying by screening through a drying method, wherein the conditions are as follows: drying at 120 deg.C under-0.085 Mpa with crawler speed of 170mm/min, feeding pump of 32Hz, and pulverizing frequency of 40 Hz; the result shows that the vacuum belt type drying time is short, the cost is low, the drying is uniform, the quality of the dried product is ensured, and the vacuum belt type drying device is suitable for large-scale production of products.

4. The product produced by the scheme is compared with the comparative example in quality detection, and the result shows that the detection indexes of 3 batches of samples are superior to those of 3 batches of samples of the comparative example, so that the feasibility and the reliability of the medicine preparation method are demonstrated.

Detailed Description

The technical solution of the present invention will be further specifically described below by way of specific examples.

Example 1

Soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 8 times of 70% ethanol as extraction solvent at constant temperature of 70 deg.C under reflux for 2 times, each for 2 hr, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.20, vacuum belt drying at 120 deg.C, vacuum degree of-0.085 Mpa, crawler speed of 170mm/min, feeding pump of 32Hz, and pulverizing frequency of 40Hz for 2 hr, and pulverizing to obtain extract.

Example 2

Soaking Glycyrrhrizae radix in saturated lime water for 8 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 6 times of 65% ethanol as extraction solvent at 60 deg.C under reflux for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.15, vacuum belt drying at 100 deg.C under vacuum degree of-0.085 Mpa, crawler speed of 150mm/min, feeding pump of 30Hz and pulverizing frequency of 30Hz for 2 hr, and pulverizing to obtain extract.

Example 3

Soaking Glycyrrhrizae radix in saturated lime water for 12 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 10 times of 75% ethanol as extraction solvent at 80 deg.C under reflux for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.25, vacuum belt drying at 150 deg.C, vacuum degree of-0.085 Mpa, track speed of 190mm/min, feeding pump of 35Hz, and pulverizing frequency of 50Hz for 2 hr, and pulverizing to obtain extract.

Example 4

Soaking Glycyrrhrizae radix in saturated lime water for 9 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 7 times of 68% ethanol as extraction solvent at 65 deg.C under reflux for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.18, vacuum belt drying at drying temperature of 105 deg.C, vacuum degree of-0.085 Mpa, track speed of 155mm/min, feeding pump of 31Hz, and pulverizing frequency of 35Hz for 1h, and pulverizing to obtain extract.

Example 5

Soaking Glycyrrhrizae radix in saturated lime water for 11 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 9 times of 72% ethanol as extraction solvent under reflux at 68 deg.C for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.20, vacuum belt drying at drying temperature of 110 deg.C, vacuum degree of-0.085 Mpa, track speed of 160mm/min, feeding pump of 32Hz, and pulverizing frequency of 40Hz for 3 hr, and pulverizing to obtain extract.

Example 6

Soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 8 times of 73% ethanol as extraction solvent at 72 deg.C under reflux for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.21, vacuum belt drying at 120 deg.C, vacuum degree of-0.085 Mpa, track speed of 180mm/min, feeding pump of 33Hz, and pulverizing frequency of 45Hz for 2 hr, and pulverizing to obtain extract.

Example 7

Soaking Glycyrrhrizae radix in saturated lime water for 8 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 6 times of 75% ethanol as extraction solvent at 75 deg.C under reflux for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.23, vacuum belt drying at 130 deg.C, vacuum degree of-0.085 Mpa, track speed of 185mm/min, feeding pump of 34Hz, and pulverizing frequency of 45Hz for 1h, and pulverizing to obtain extract.

Example 8

Soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 9 times of 69% ethanol as extraction solvent under reflux at 78 deg.C for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.22, vacuum belt drying at 135 deg.C under-0.085 Mpa with crawler speed of 190mm/min and feeding pump of 35Hz and pulverizing frequency of 50Hz for 3 hr, and pulverizing to obtain extract.

Example 9

Soaking Glycyrrhrizae radix in saturated lime water for 11 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 10 times of 65% ethanol as extraction solvent at 68 deg.C under reflux for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.17, vacuum belt drying at 138 deg.C, vacuum degree of-0.085 Mpa, crawler speed of 170mm/min, feeding pump 33Hz and pulverizing frequency of 36Hz for 1 hr, and pulverizing to obtain extract.

Example 10

Soaking Glycyrrhrizae radix in saturated lime water for 10 hr, filtering, and collecting filtrate and residue; 2) extracting the residue with 8 times of 72% ethanol as extraction solvent under reflux at 68 deg.C for 2 times and 2 hr each time, filtering, and mixing filtrates; 3) mixing the filtrates of steps 1) and 2), concentrating under reduced pressure to obtain soft extract with relative density of 1.20, vacuum belt drying at 130 deg.C, vacuum degree of-0.085 Mpa, track speed of 160mm/min, feeding pump of 32Hz, and pulverizing frequency of 45Hz for 2 hr, and pulverizing to obtain extract.

To further verify the effectiveness of the present invention, the inventors performed a series of verification tests, excerpted as follows:

1 investigation of extraction Process

1.1 sample: glycyrrhiza uralensis, origin Gansu, batch No. 20200325

1.2 reagent: saturated limewater, methanol, ethyl acetate, diethyl ether, distilled water, anhydrous ethanol, and rutin;

1.3 Instrument: beaker, volumetric flask, pipette, glass rod, graduated cylinder, reflux unit, filter paper, HH-4 digital display constant temperature water bath, analytical balance, AB104.N electronic balance, Buchner funnel, SHZ-C type circulating water multipurpose vacuum pump, and ultraviolet spectrophotometer.

1.4 investigation evaluation index: total flavone content

1.5 examination of the immersion extraction solvent and the time

1.5.1 protocol: according to the properties of flavonoids, 5 solvents are selected temporarily as soaking extraction solvents, namely: soaking 70% ethanol, methanol, ethyl acetate, diethyl ether, and saturated lime water in 6 times of 1.1 times of Glycyrrhrizae radix for 8 hr, 10 hr, and 12 hr respectively, concentrating into soft extract, collecting soft extract, measuring total flavone content by ultraviolet spectrophotometry with rutin control as standard curve, and finding the result shown in Table 1.

TABLE 1 comparative table for investigation of solvent extraction by immersion

As a result: as shown in Table 1, the total flavone content is relatively high when soaked in saturated lime water, and the total flavone content is equivalent when the soaking time is 10h and 12h, so the soaking time of 10h is preferred.

1.6 examination of reflux extraction solvent

1.6.1 protocol: soaking Glycyrrhrizae radix residue in saturated lime water for 10 hr respectively to obtain 1 part of Glycyrrhrizae radix residue, extracting with 10 times of 70% ethanol, methanol, ethyl acetate, diethyl ether, and saturated lime water under reflux at constant temperature of 70 deg.C for 2 hr, concentrating, collecting concentrated solution, and measuring total flavone content by ultraviolet spectrophotometry with rutin as reference curve, with the results shown in Table 2.

TABLE 2 examination and comparison table of reflux extraction solvent

Name of solvent for reflux extraction	Total Flavonoids content (mg/g)
		70% ethanol	16.10
Methanol	13.63
		Ethyl acetate	12.66
Ether (A)	13.88
		Saturated lime water	10.13

As a result: as shown in Table 2, the total flavone content was higher when 70% ethanol was used as the solvent for the reflux extraction. Therefore, 70% ethanol is preferable. Other extraction reagents are not considered further below.

1.7 examination of the amount of solvent to be refluxed

1.7.1 protocol: 3 parts of liquorice herb residues after being soaked in saturated limewater for 10 hours are respectively taken, 6 times, 8 times and 10 times of 70% ethanol are respectively taken as reflux extraction solvents, reflux extraction is carried out for 2 hours at the constant temperature of 70 ℃, concentration is carried out again, concentrated solution is taken, rutin reference substance is taken as a standard curve, and the content of total flavonoids is measured according to an ultraviolet spectrophotometer measurement method, and the result is shown in table 3.

Table 3 investigation and comparison table of the amount of reflux extraction solvent

Sample numbering	70% ethanol times	Total Flavonoids content (mg/g)
			1	6	11.30
2	8	15.53
			3	10	15.59

As a result: as is clear from Table 3, the content of total flavonoids extracted by 10-fold and 8-fold reflux extraction with 70% ethanol was equivalent, while the content of total flavonoids extracted by 6-fold extraction was low, and 8-fold solvent was preferable in view of the overall situation.

1.8 examination of reflux extraction time

1.8.1 protocol: soaking 3 parts of the residue in saturated limewater for 10 hr, extracting with 8 times of 70% ethanol at constant temperature of 70 deg.C under reflux for 1 hr, 2 hr, and 3 hr, concentrating, collecting the concentrated solution, measuring the content of total flavonoids by ultraviolet spectrophotometry with rutin as standard curve, and finding the result shown in Table 4.

TABLE 4 comparison table for investigation of reflux extraction time

Sample numbering	Reflux time (h)	Total Flavonoids content (mg/g)
			1	1	11.56
2	2	14.89
			3	3	14.92

As a result: as can be seen from Table 4, the total flavone contents in the extraction time periods of 2h and 3h are equivalent to each other, and the total flavone content in the extraction time period of 1h is relatively low, and the extraction time period of 2h is preferred in comprehensive consideration.

1.9 examination of the number of reflux extractions

1.9.1 scheme: soaking 3 parts of the residue in saturated limewater for 10 hr, extracting with 8 times of 70% ethanol at constant temperature of 70 deg.C under reflux for 1 time, 2 times, and 3 times, each for 2 hr, concentrating, collecting the concentrated solution, measuring total flavone content by ultraviolet spectrophotometry with rutin as reference curve, and finding the result shown in Table 5.

TABLE 5 comparison table for examining reflux extraction times

Sample numbering	Number of times of reflux	Total Flavonoids content (mg/g)
			1	1	12.23
2	2	15.00
			3	3	15.10

As a result: as can be seen from Table 5, the content of total flavonoids after 2 and 3 extractions is not very different, and the content of total flavonoids after 1 extraction is relatively low, and 2 extractions are preferred in comprehensive consideration.

And (4) conclusion: according to the analysis of the results, the preferable scheme of liquorice extraction is as follows: soaking Glycyrrhrizae radix in saturated lime water for 10 hr, and filtering; extracting the residue with 8 times of 70% ethanol as extraction solvent at constant temperature of 70 deg.C under reflux for 2 times, each for 2 hr, filtering, mixing filtrates, and concentrating.

2. Investigation of drying Process

2.1 instruments, equipments and raw and auxiliary materials

2.1.1 instruments, devices: 6m3 extraction and concentration machine set, DGJ90-100 low-temperature vacuum belt type dryer, spray dryer, freeze dryer, vacuum drying box, high performance liquid chromatography analyzer, and rapid moisture tester.

2.1.2 samples: a concentrated extract of Glycyrrhiza uralensis was prepared as described in example 1.

2.2 scheme: the concentrated extracts were dried in 3 parts each by vacuum drying, spray drying, freeze vacuum drying, and low-temperature vacuum belt drying, and the results are shown in Table 6.

Table 6 comparative results of drying method table

As a result: as can be seen from Table 6, the low-temperature vacuum belt drying method is characterized by the shortest drying time, low water content and uniform water content, and the other methods are characterized by long drying time and non-uniform drying. Therefore, low temperature vacuum belt drying is preferred.

2.3 screening of parameters for Low temperature vacuum Belt drying Process

2.3.1 sample: extract obtained by grinding in accordance with "example 1

2.3.2 screening of drying temperature

2.3.2.1 scheme: 3 portions of each sample were taken and dried at 100 ℃ and 120 ℃ and 150 ℃ for 1 hour, respectively, and the results are shown in Table 7.

TABLE 7 drying temperature comparison results table

As a result: as can be seen from Table 7, the drying temperature is 100-150 ℃ and the moisture content is less than 1.5%, but the total flavone content is highest at the drying temperature of 120 ℃, and the drying temperature of 120 ℃ is preferred to be the low-temperature vacuum belt drying temperature.

2.3.3 screening of track speeds

2.3.3.1 protocol: samples were taken 3 parts each, and the caterpillar speeds were set to 150mm/min, 170mm/min and 190mm/min, respectively, and the drying temperature was set to 120 ℃ for 1 hour, and the results are shown in Table 8.

TABLE 8 track speed comparison results table

As a result: as can be seen from Table 8, the track speed is 150-190mm/min, the moisture content is lower than 1.5%, but the total flavone content is highest at 170mm/min, and in comprehensive consideration, 170mm/min is the preferred low-temperature vacuum belt drying track speed.

2.3.4 feed Pump frequency screening

2.3.4.1 scheme: 3 portions of each sample were dried for 1 hour at a caterpillar speed of 170mm/min and a drying temperature of 120 ℃ at a feed pump frequency of 30, 40 and 50Hz, respectively, and the results are shown in Table 9.

TABLE 9 feed Pump frequency comparison results Table

As a result: as can be seen from Table 9, the feed pump frequency was 30 to 50Hz, the moisture content was less than 1.5%, but the total flavone content was the highest at 40Hz, and 40Hz was preferred for the feed pump frequency of the low temperature vacuum belt drying.

2.3.5 feed Pump frequency screening

2.3.5.1 scheme: 3 portions of each sample were taken, and dried for 1 hour at a crawler speed of 170mm/min, a drying temperature of 120 ℃, a feed pump of 40Hz, and crushing frequencies of 30Hz, 32Hz, and 35Hz, respectively, and the results are shown in Table 10.

TABLE 10 crushing frequency comparison results table

As a result: as is clear from Table 10, the feed pump frequency was 30 to 35Hz, the moisture content was less than 1.5%, and the total flavone content was comparable at the pulverizing frequencies of 32Hz and 35Hz, and 32Hz was preferred for the pulverizing frequency of the low-temperature vacuum belt drying.

2.3.6 screening for drying time

2.3.6.1 scheme: 3 portions of each sample were dried for 1 hour, 2 hours and 3 hours respectively at a caterpillar speed of 170mm/min, a drying temperature of 120 ℃, a feeding pump of 40Hz and a crushing frequency of 32Hz, and the results are shown in Table 11.

TABLE 11 comparative drying time results table

As a result: as can be seen from Table 11, the drying time is 1-3h, the water content is lower than 1.5%, the total flavone content is highest when the drying time is 2h, and 2h is the preferred drying time of the low-temperature vacuum belt drying.

And (4) conclusion: the preferred parameters of the low-temperature vacuum belt drying are as follows: the drying temperature is 120 ℃, the vacuum degree is-0.085 Mpa, the track speed is 170mm/min, the feeding pump is 32Hz, and the crushing frequency is 40 Hz. The drying time is 2 h.

3 sample content comparison test

3.1 sample: the extract of the licorice root of "1.1" was obtained by the procedure of "example 1", "comparative example 1(CN 201911414265.5)" "comparative example 2(CN 201910133338.7)", and 3 parts of each sample were obtained.

3.2 investigation evaluation index: total flavone content.

3.3 scheme: the rutin control is used as a standard curve, and the content of the total flavone is measured by an ultraviolet spectrophotometer measurement method, and the result is shown in table 12.

Table 12 comparative results of drying method table

As a result: as can be seen from Table 12, the licorice extract produced by the process of the present invention has a total flavone content of 2.8% or more, which is higher than that of the extract produced by the comparative example, and further verifies the feasibility and reliability of the process of the present invention.

And (4) conclusion:

1. according to the extraction process, the soaking solvent and the soaking time are considered in the soaking stage, the saturated limewater is used as the solvent, the liquorice is soaked for 10 hours and then filtered, the filtrate and the dregs are reserved, and the saturated limewater is relatively safe and cheap, and has high content of total flavonoids.

2. In the reflux extraction stage in the extraction process, the optimal scheme of reflux extraction is obtained through the investigation of parameters such as the amount of the extraction solvent, the time of the extraction solvent, the extraction times, the extraction temperature and the like, and the reasonability and the reliability of the extraction process are further proved.

3. The invention obtains the conditions of low-temperature vacuum belt type drying by screening through a drying method, wherein the conditions are as follows: drying at 120 deg.C under-0.085 Mpa with crawler speed of 170mm/min, feeding pump of 32Hz, and pulverizing frequency of 40 Hz; the result shows that the vacuum belt type drying time is short, the cost is low, the drying is uniform, the quality of the dried product is ensured, and the method is suitable for large-scale production of products.

4. The product produced by the scheme is compared with the comparative example in quality detection, and the result shows that the detection indexes of 3 batches of samples are superior to those of 3 batches of samples of the comparative example, so that the feasibility and the reliability of the medicine preparation method are demonstrated.

Although the invention has been described in detail in the foregoing by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that various modifications and improvements can be made thereto without departing from the spirit of the invention.