阅读说明：本技术 一种罗汉果甜苷v的制备方法 (Preparation method of mogroside V ) 是由 何安乐 黄华学 熊瑶 刘庚贵 黄�俊 于 2021-08-06 设计创作，主要内容包括：本发明涉及植物提取技术领域,公开了一种罗汉果甜苷V的制备方法。本发明所述制备方法克服现有传统的工艺技术,从减少树脂层析次数、优化层析工艺及二次纯化解吸液等入手,创新性的采用亚临界溶剂清洗除杂、解吸粗品高温固杂及粗品亚临界溶剂二次纯化工艺进行提取分离和纯化,在只需要一次树脂层析的前提下,可同时制得两种规格的高含量罗汉果甜苷V产品,其含量分别≥72％和≥95％,总收率92％以上。且工艺对环境友好、工艺简单,适用于规模化生产。(The invention relates to the technical field of plant extraction, and discloses a preparation method of mogroside V. The preparation method provided by the invention overcomes the defects of the existing traditional process technology, starts with reduction of resin chromatography times, optimization of chromatography process, secondary purification of desorption solution and the like, innovatively adopts subcritical solvent cleaning and impurity removal, desorption of crude product high-temperature solid impurity and secondary purification process of crude product subcritical solvent for extraction, separation and purification, and can simultaneously prepare two specifications of high-content mogroside V products with the contents respectively more than or equal to 72% and more than or equal to 95% and the total yield more than 92% on the premise of only needing one resin chromatography. And the process is environment-friendly, simple and suitable for large-scale production.)

1. A preparation method of mogroside V is characterized by comprising the following steps:

step 1, leaching fructus momordicae, filtering leaching liquor, and taking filtrate as upper injection;

step 2, the upper injection liquid passes through a chromatographic column to carry out chromatographic adsorption;

step 3, cleaning the chromatographic column to remove impurities, then carrying out linear continuous desorption by using methanol or ethanol as a desorption solvent, taking the mogroside V content of 70-80% as a demarcation point, and collecting the desorption liquid I and the desorption liquid II in sections;

step 4, concentrating and drying the desorption solution, then baking at high temperature, then carrying out leakage leaching, and collecting leakage leaching liquor;

and 5, filtering the leakage leaching liquid membrane to collect trapped liquid, and concentrating and drying to obtain the mogroside V.

2. The method according to claim 1, wherein the chromatographic column in step 2 is a macroporous adsorbent resin chromatographic column.

3. The method according to claim 1, wherein the upper column liquid is degassed before being loaded into the column in step 2.

4. The preparation method according to claim 1, wherein the cleaning and impurity removal in the step 3 is performed by using an acidic aqueous solution in a subcritical state.

5. The method according to claim 4, wherein the acidic aqueous solution is a volatile acid aqueous solution.

6. The method as claimed in claim 4, wherein the subcritical state is a pressure of 5-10MPa and a temperature of 110-.

7. The method according to claim 1, wherein the concentration of methanol or ethanol in step 3 is in the range of 0 to 65% by volume.

8. The method as claimed in claim 1, wherein the high temperature in step 4 is 150-200 ℃.

9. The method according to claim 1, wherein the leaching in step 4 is a subcritical water solvent leaching.

10. The method as claimed in claim 9, wherein the subcritical state is a pressure of 10-15MPa and a temperature of 140-.

Technical Field

The invention relates to the technical field of plant extraction, in particular to a preparation method of mogroside V.

Background

The momordica grosvenori is named as Lajiang fruit and false balsam pear, and is a plant known as Momordica grosvenori, which is a cucurbitaceae plant momordica grosvenori fruit harvested for many years. The momordica grosvenori is a specific economic and medicinal plant in China, has an application history of more than 300 years, is distributed in hot spots and subtropical mountain areas such as Guangxi, Hunan, Guangdong, Hainan and Guizhou, and has main production areas distributed in Yongfu county, Lingui county and Rogan county of Guangxi Guilin due to special requirements on resin environmental conditions. The traditional Chinese medicine composition is taken as a common traditional Chinese medicine from the Chinese pharmacopoeia of 1977 edition, has the effects of clearing heat, moistening lung, smoothing intestine and relaxing bowels, and is mainly used for treating cough caused by lung heat or lung dryness, pertussis, phlegm fire cough, blood dryness constipation and other symptoms; in addition, the momordica grosvenori is also an excellent cold drink, can refresh and promote the secretion of saliva or body fluid, can prevent respiratory tract infection, can prolong life after being taken for a long time, and is known as the oriental fruit and the longevity fruit.

Mogroside is unique to momordica grosvenori, most studied chemical components are used, the mogroside V content is the highest, the sweetness of the mogroside V is about 300 times of that of cane sugar, the calorie of the mogroside V is close to 0, the mogroside V is a main sweet substance of momordica grosvenori and is an excellent natural sweetener, the existing mogroside products with different contents are produced on a large scale at present, and the mogroside V content is mainly used as a measurement standard.

CN107602653 discloses a method for extracting mogroside from fresh fructus Siraitiae Grosvenorii, which comprises breaking shell of fresh fruit, extracting, adsorbing with macroporous adsorbent resin, desorbing, decolorizing with resin, concentrating, and drying. The method designs two chromatographic processes of macroporous adsorption resin adsorption and macroporous resin decolorization, the operation is troublesome, the production efficiency is low, a large amount of acid and alkali are needed for activating the resin in the decolorization process, the environment is not friendly, the content of the prepared product is 90.7 percent at most, and the content is low.

CN111333691 discloses a preparation method of mogroside V, which comprises the steps of drying fresh fruits, extracting with ethanol, decoloring with activated carbon, performing macroporous adsorption resin chromatography, desorbing with ethanol, concentrating, drying, removing impurities by ultrafiltration, eluting with a polyamide column, concentrating and drying to obtain a mogroside V product with the concentration of more than 98%. The process involves two times of column chromatography, and the drying treatment is carried out for 3 times before and after, so that the operation is more complicated, and the production cost is relatively high.

CN107629105 discloses a purification method of flavor mogroside V, which comprises polyamide adsorption, effluent alkali adjustment, ultrafiltration, anion and cation exchange resin decolorization, concentration and drying. The process relates to the activation process of anion-cation exchange resin, uses a large amount of acid and alkali, and is not environment-friendly. And the content of the prepared product is not more than 60 percent.

CN103923152A discloses a mogroside V extraction method, which comprises the steps of taking fresh momordica grosvenori as raw materials, cleaning, crushing, saccharifying, extracting and concentrating with water, settling and centrifuging, multi-column macroporous adsorption resin segmentation analysis, ion exchange, concentrating, refining with silica gel, concentrating and spraying and the like to obtain the final product mogroside V extract. However, the method is complex, long in period and high in cost, and is not suitable for industrial production.

CN108276465 discloses a method for separating and purifying mogroside V by using subcritical water desorption technology, which specifically comprises the steps of momordica grosvenori leaching, solid-liquid separation, membrane filtration, macroporous adsorption resin adsorption, subcritical water desorption, concentration and drying. The product content of the process does not exceed 59.26% at most.

CN111978365 discloses a preparation method of mogroside V, which comprises the steps of raw material crushing, leaching, concentrating, diluting, resin decoloring, membrane filtering, vacuum concentrating and drying to obtain the mogroside. The process relates to the activation process of anion-cation exchange resin, uses a large amount of acid and alkali, is not environment-friendly, and the content of the prepared product is not more than 65 percent.

CN105218612 discloses a method for improving purity of mogroside V of worker, which comprises crushing fresh fructus Siraitiae Grosvenorii, extracting with ethanol, concentrating, performing enzymolysis, performing membrane filtration, adsorbing with resin, desorbing, concentrating, performing membrane filtration, desalting with resin, decolorizing with activated carbon, sterilizing, and drying. The process is very complicated and is not suitable for large-scale production.

CN104558088 discloses a method for extracting mogroside V from fructus Siraitiae Grosvenorii, which comprises microwave countercurrent extraction, multi-stage filtration, macroporous resin separation, multi-stage filtration, and drying. This process involves excessive filtration, is extremely cumbersome to operate, and membrane filtration results in a reduced yield. And the content of the prepared product mogroside V is below 70%.

CN110669095 discloses an extraction method of high-purity mogroside V, which comprises freezing, instantaneous heating, leaching, clarifying, purifying with C18 preparative column, concentrating, and drying. The process is preparative liquid chromatography, the column packing material is C18, the price is very high, the production capacity is very small, and the process is not suitable for large-scale production.

CN106432394 discloses a method for extracting total glycosides from fructus Siraitiae Grosvenorii, which comprises extracting with ethanol, adsorbing with macroporous resin, desorbing with ethanol, adsorbing with macroporous resin again, concentrating, and drying. The process does not explain the content of mogroside V, does not know the quality of the process,

the extraction and purification method of mogroside V in the above-mentioned patent basically adopts the steps of making water/alcohol extraction of momordica grosvenori, then making solid-liquid separation, membrane filtration, making adsorption and desorption by using macroporous resin, decolorizing by using ion exchange resin or active carbon, concentrating and drying so as to obtain the invented product with high content. The resin chromatography is a key step for improving the product content, the disclosed patents basically carry out two or even three times of resin chromatography in order to obtain a high-content mogroside V product, and some chromatographs use anion-cation exchange resin for desalting and decoloring, so that the environmental friendliness is inevitably caused by the use of acid and alkali in the activation process of the anion-cation exchange resin, and the sewage treatment difficulty is high. If only one resin chromatography is used, it may occur that the prepared product content is low or that the throughput is too small for scale-up using preparative chromatography columns.

Disclosure of Invention

In view of the above, the present invention aims to provide a preparation method of mogroside V, such that the preparation process can obtain a product with a higher mogroside V content on the premise of one-time resin chromatography.

In order to achieve the above purpose, the invention provides the following technical scheme:

a method for preparing mogroside V comprises the following steps:

step 1, leaching fructus momordicae, filtering leaching liquor, and taking filtrate as upper injection;

step 2, the upper injection liquid passes through a chromatographic column to carry out chromatographic adsorption;

step 3, cleaning the chromatographic column to remove impurities, then carrying out linear continuous desorption by using methanol or ethanol as a desorption solvent, taking the mogroside V content of 70-80% as a demarcation point, and collecting the desorption liquid I and the desorption liquid II in sections;

step 4, concentrating and drying the desorption solution, then baking at high temperature, then carrying out leakage leaching, and collecting leakage leaching liquor;

and 5, filtering the leakage leaching liquid membrane to collect trapped liquid, and concentrating and drying to obtain the mogroside V.

Wherein, the fructus momordicae in the step 1 is preferably fresh or dry fructus momordicae, preferably dry fructus momordicae, and the leaching is performed by a tank type extraction or a continuous countercurrent extraction mode by using water as a leaching solvent. The mass ratio of the extracted fresh fructus momordicae to the water is 1: 3-6; the feed liquid mass ratio of the dried momordica grosvenori fruits to the water is 1: 15-30; the leaching temperature is 80-100 ℃; the leaching time is 2-4 h.

Preferably, in step 1, solid-liquid separation is performed after leaching, in order to achieve separation of the extraction residue and the extraction liquid, the separation includes any one or a combination of horizontal screw centrifugation and disc centrifugation, and preferably horizontal screw centrifugation and then disc centrifugation.

Preferably, in step 1, the filtration is ultrafiltration membrane filtration, and the ultrafiltration membrane has a molecular weight cut-off of 5000-.

In the step 2, the chromatographic column is a closed high-pressure-resistant chromatographic column filled with macroporous adsorption resin. The model of the macroporous adsorption resin is any one of D101, AB-8, LX-T28, LX-T5, LXD-762 and LX-94. The column packing mode of the chromatographic column is as follows: loading activated macroporous adsorbent resin into column, injecting pure water to above the resin, sealing two ends, vacuumizing to maintain vacuum degree (-0.06MPa) - (-0.09MPa), maintaining for 20-30min, and recovering normal pressure.

In addition, degassing treatment is carried out before the upper column liquid is loaded on the column in the step 2. The degassing method is vacuum pumping treatment or ultrasonic treatment. The vacuum pumping treatment is to maintain the vacuum degree at (-0.06MPa) - (-0.09MPa) for 20-30 min; the ultrasonic treatment is 30-50KHZ and 100-300W, and is kept for 5-10 min.

Preferably, the height-diameter ratio of the chromatographic column is 1:3-8, and the flow rate of the chromatographic column is 0.5-1.0 BV/h; and (5) when the effluent liquid of the column feeding is sweet, the leakage point is the leakage point, and the column feeding is finished.

Preferably, in the step 3, the cleaning and impurity removal are carried out on the column by adopting subcritical acidic aqueous solution, and the pH value is 2-4. In order to reduce the acid removal step after impurity removal, a volatile acid aqueous solution such as hydrochloric acid is further preferred; if non-volatile acids such as sulfuric acid, citric acid, acetic acid, malic acid, etc. are used, a neutral water washing column is additionally required after impurity removal. Wherein the subcritical state is a pressure of 5-10MPa and a temperature of 110-. The flow rate of the column washing is 2-3BV/h, and the volume of the column washing is 4-5 BV.

Preferably, the concentration of methanol or ethanol in step 3 is in the range of 0-65% by volume, and the linear desorption is carried out by using 0-65% by volume of methanol or ethanol aqueous solution, namely, the linear uniform speed is increased to 65% from 0. The desorption flow rate is preferably 0.5-1.5BV/h, and the volume of the desorption solvent is preferably 10-20 BV.

Collecting in a segmented manner in the step 3, namely combining and collecting parts with the mogroside V (dry basis) content of less than 70% or less than 80% in the desorption liquid to obtain desorption liquid I; and combining and collecting the parts of which the content is not less than 70% or not less than-80% to obtain desorption liquid II. During the collection process, the demarcation point is determined by using a small-section collection test, for example, 1 bottle of effluent is separately collected for every 1L, and the content test is carried out one by one.

Preferably, in step 4, the concentration is performed to remove part of water and methanol/ethanol, and the concentration is performed until the soluble solid content is 45-65%. The concentration mode is any one of rotary evaporation type concentration, falling film type concentration, single-effect evaporation type concentration and multi-effect evaporation type concentration. The drying is to remove the residual water, and the specific method is any one of vacuum drying and vacuum microwave drying. After drying, the method also preferably comprises crushing, sieving and sieving the powder by a 60-120 mesh sieve

Preferably, in the step 4, the high-temperature baking is to perform high-temperature treatment on the concentrated and dried crude product, wherein the high temperature is to keep the crude product at a constant temperature of 150 ℃ and 200 ℃ for 20-40 min. In a specific embodiment of the present invention, the high temperature may be selected to be 150 ℃, 160 ℃, 170 ℃, 180 ℃ or 200 ℃, and the holding time is 20min, 30min or 40 min.

Preferably, in the step 4, the crude product after high-temperature baking is filled into a column, the height-diameter ratio of the column is 1:5-10, the column is filled with a leaching solvent in a column filling mode, the solvent is used in an amount which is 20-40 times of the mass of the crude product, and the leaching flow rate is 0.5-1.0 BV/h; the leaching uses water in a subcritical state as a solvent for leaching, the subcritical state is a pressure of 10-15MPa and a temperature of 140-.

Preferably, in step 5, the membrane filtration is nanofiltration membrane filtration, and the molecular weight cut-off of the nanofiltration membrane is preferably 200-800Da, and in the specific embodiment of the invention, the molecular weight cut-off is 500 Da.

Preferably, in step 5, the concentration is performed for the purpose of removing water in the eluent, including but not limited to vacuum concentration and membrane concentration, and the concentration is performed until the soluble solid is 40-60%; the drying is for removing water, and includes but is not limited to one of vacuum drying, microwave drying, belt drying and forced air drying. The drying process preferably comprises crushing and sieving treatment, and the crushed materials pass through a 100-200-mesh sieve.

The method overcomes the defects of the prior traditional process technology, starts from reducing the times of resin chromatography, optimizing the chromatography process, secondarily purifying the desorption solution and the like, creatively adopts the subcritical solvent cleaning impurity removal process, the desorption crude product high-temperature solid impurity and the subcritical solvent secondary purification process for extraction, separation and purification, and can simultaneously prepare two specifications of high-content mogroside V products with the contents respectively more than or equal to 72 percent and more than or equal to 95 percent and the total yield more than 92 percent on the premise of only needing one resin chromatography. And the process is environment-friendly, simple and suitable for large-scale production.

Detailed Description

The embodiment of the invention discloses a preparation method of mogroside V, and a person skilled in the art can appropriately improve process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications which would be obvious to those skilled in the art are deemed to be included within the invention. While the process of the present invention has been described in terms of preferred embodiments, it will be apparent to those skilled in the art that variations and modifications, as well as other suitable variations and combinations of the process described herein, may be made to implement and use the techniques of the present invention without departing from the spirit and scope of the invention.

The raw material of the momordica grosvenori used in the implementation of the invention can be purchased from the Hainan Huacheng biological resource GmbH, and the raw material or chemical reagent used in the implementation of the invention is obtained through a conventional commercial way if no special description is provided.

The test method adopted by the present invention is explained as follows:

the mogroside V is determined according to the method specified in GB188677-2016 food safety national standard food additive mogroside.

The method relates to a comparison experiment, and all groups of other experiment environments are consistent except for the difference, so that the results are comparable.

The preparation method of mogroside V provided by the invention is further explained below.

Example 1: exemplary preparation method of the invention

(1) Preparing a column loading solution: adding 50kg of fresh fructus Siraitiae Grosvenorii into 5 times of 90 deg.C hot water, leaching for three times, filtering, centrifuging for solid-liquid separation, mixing, collecting leaching liquor, passing through ultrafiltration membrane with molecular weight cutoff of 20000Da, and collecting permeate to obtain 267kg of upper column liquid.

(2) Chromatography and adsorption: loading 5L D101 macroporous adsorbent resin activated by ethanol into a column with height-diameter ratio of 1:4, vacuumizing to-0.06 MPa, maintaining for 20min, and recovering normal pressure. Then, the column feeding liquid subjected to vacuum degassing is carried out at the flow rate of 0.6BV/h, and the column feeding is stopped until the effluent liquid has sweet taste;

(3) and (3) column washing and desorption: firstly, washing the column by using a hydrochloric acid aqueous solution in a subcritical state (namely the pressure in the chromatographic column is 5MPa, the temperature is 140 ℃, and the pH value is 4) at the flow rate of 2BV/h and the column washing volume of 5 BV; then using 10BV ethanol water solution with volume fraction of 0-65% to carry out continuous linear elution, and respectively collecting desorption liquid I with content lower than 70% and desorption liquid II with content not lower than 70%.

(4) Concentration and drying: concentrating the collected desorption solution by a single-effect vacuum concentrator until the content of soluble solids is 50.2 percent and 53.8 percent, and respectively obtaining 43.2g of crude product I and 131.4g of crude product II after microwave drying and crushing;

(5) column leaching: respectively and independently baking the obtained crude product I and crude product II at the constant temperature of 160 ℃ for 30min, then loading the crude product I and the crude product II into a column chromatography column with the diameter-height ratio of 1:7, then carrying out leakage leaching by using a subcritical water solution with the temperature of 200 ℃ and the pressure of 10MPa, wherein the volume of the subcritical water is 1.5L and 4L respectively, the leakage flow rate is 0.5BV/h, and respectively collecting leakage leaching liquor to obtain the leakage leaching liquor I and the leakage leaching liquor II.

(6) Membrane filtration: respectively passing the obtained seepage leaching liquor I and seepage leaching liquor II through a 500Da nanofiltration membrane, and respectively collecting trapped fluid I and trapped fluid II;

(7) concentrating and drying: and respectively concentrating the collected trapped fluid I and trapped fluid II by using a single-effect vacuum concentrator until the content of soluble solids is 48.2 percent and 50.1 percent, and performing microwave drying, crushing and sieving to obtain the mogroside V products with different contents.

Weighing and detecting to respectively obtain two kinds of mogroside V with different specifications, wherein the weight and the content are respectively as follows: product I: 28.6g, 78.3%; and (2) product II: 96.4g and 98.3 percent. The total yield was 93.21%.

Example 2: exemplary preparation method of the invention

(1) Preparing a column loading solution: adding 50kg of fresh fructus Siraitiae Grosvenorii into 5 times of 90 deg.C hot water, leaching for three times, filtering, centrifuging to separate solid and liquid, mixing, collecting leaching solution, passing through ultrafiltration membrane with molecular weight cutoff of 8000Da, and collecting permeate to obtain 267kg of upper column liquid.

(2) Chromatography and adsorption: loading 5L AB-8 type macroporous adsorbent resin activated by ethanol into column with height/diameter ratio of 1:4, vacuumizing to-0.06 MPa, maintaining for 20min, and recovering normal pressure. Then, the column feeding liquid subjected to vacuum degassing is carried out at the flow rate of 0.6BV/h, and the column feeding is stopped until the effluent liquid has sweet taste;

(3) and (3) column washing and desorption: firstly, washing the column by using a hydrochloric acid aqueous solution in a subcritical state (namely the pressure in the chromatographic column is 5MPa, the temperature is 140 ℃, and the pH value is 2) at the flow rate of 2BV/h and the column washing volume of 5 BV; then using 10BV ethanol water solution with volume fraction of 0-65% to carry out continuous linear elution, and respectively collecting desorption liquid I with content lower than 70% and desorption liquid II with content not lower than 70%.

(4) Concentration and drying: concentrating the collected desorption solution by a single-effect vacuum concentrator until the content of soluble solids is 49.4 percent and 51.3 percent respectively, and performing microwave drying and crushing to obtain 40.2g of crude product I and 130.2g of crude product II respectively;

(5) column leaching: respectively and independently baking the obtained crude product I and crude product II at the constant temperature of 160 ℃ for 30min, then loading the crude product I and the crude product II into a column chromatography column with the diameter-height ratio of 1:7, then carrying out leakage leaching by using a subcritical water solution with the temperature of 200 ℃ and the pressure of 10MPa, wherein the volume of the subcritical water is 1.5L and 4L respectively, the leakage flow rate is 0.5BV/h, and respectively collecting leakage leaching liquor to obtain the leakage leaching liquor I and the leakage leaching liquor II.

(6) Membrane filtration: respectively passing the obtained seepage leaching liquor I and seepage leaching liquor II through a 500Da nanofiltration membrane, and respectively collecting trapped fluid I and trapped fluid II;

(7) concentrating and drying: and respectively concentrating the collected trapped fluid I and the trapped fluid II by using a single-effect vacuum concentrator until the content of soluble solids is 50.1 percent and 53.8 percent, and performing microwave drying, crushing and sieving to obtain the mogroside V products with different contents.

Weighing and detecting to respectively obtain two kinds of mogroside V with different specifications, wherein the weight and the content are respectively as follows: product I: 30.2g, 72.1%; and (2) product II: 98.8g, 96.7%. The total yield was 93.33%.

Example 3: exemplary preparation method of the invention

(1) Preparing a column loading solution: adding 50kg of fresh fructus Siraitiae Grosvenorii into 5 times of 90 deg.C hot water, extracting for three times, filtering, centrifuging for solid-liquid separation, mixing, collecting extractive solutions, passing through ultrafiltration membrane with molecular weight cutoff of 10000Da, and collecting the filtrate to obtain 267kg of upper column liquid.

(2) Chromatography and adsorption: loading 5L D101 macroporous adsorbent resin activated by ethanol into a column with height-diameter ratio of 1:4, vacuumizing to-0.06 MPa, maintaining for 20min, and recovering normal pressure. Then, the column feeding liquid subjected to vacuum degassing is carried out at the flow rate of 0.6BV/h, and the column feeding is stopped until the effluent liquid has sweet taste;

(3) and (3) column washing and desorption: firstly, washing the column by using a hydrochloric acid aqueous solution in a subcritical state (namely the pressure in the chromatographic column is 5MPa, the temperature is 110 ℃, and the pH value is 2) at the flow rate of 2BV/h and the column washing volume of 5 BV; then using 10BV ethanol water solution with volume fraction of 0-65% to carry out continuous linear elution, and respectively collecting desorption liquid I with content lower than 70% and desorption liquid II with content not lower than 70%.

(4) Concentration and drying: concentrating the collected desorption solution to the soluble solid content of 53.6% and 56.1% respectively by a single-effect vacuum concentrator, and respectively obtaining 42.1g of crude product I and 133.1g of crude product II after microwave drying and crushing;

(5) column leaching: respectively and independently baking the obtained crude product I and crude product II at the constant temperature of 160 ℃ for 30min, then loading the crude product I and the crude product II into a column chromatography column with the diameter-height ratio of 1:7, then carrying out leakage leaching by using a subcritical water solution with the temperature of 200 ℃ and the pressure of 10MPa, wherein the volume of the subcritical water is 1.5L and 4L respectively, the leakage flow rate is 0.5BV/h, and respectively collecting leakage leaching liquor to obtain the leakage leaching liquor I and the leakage leaching liquor II.

(6) Membrane filtration: respectively passing the obtained seepage leaching liquor I and seepage leaching liquor II through a 500Da nanofiltration membrane, and respectively collecting trapped fluid I and trapped fluid II;

(7) concentrating and drying: and respectively concentrating the collected trapped fluid I and the trapped fluid II by using a single-effect vacuum concentrator until the content of soluble solids is 50.2 percent and 54.2 percent, and performing microwave drying, crushing and sieving to obtain the mogroside V products with different contents.

Weighing and detecting to respectively obtain two kinds of mogroside V with different specifications, wherein the weight and the content are respectively as follows: product I: 28.3g, 79.1%; and (2) product II: 98.8g, 97.6%. The total yield was 94.5%.

Example 4: exemplary preparation method of the invention

(1) Preparing a column loading solution: adding 50kg of fresh fructus Siraitiae Grosvenorii into 5 times of 90 deg.C hot water, leaching for three times, filtering, centrifuging for solid-liquid separation, mixing, collecting leaching solution, passing through ultrafiltration membrane with molecular weight cutoff of 15000Da, and collecting permeate to obtain 267kg of upper column liquid.

(2) Chromatography and adsorption: loading 5L D101 macroporous adsorbent resin activated by ethanol into a column with height-diameter ratio of 1:4, vacuumizing to-0.06 MPa, maintaining for 20min, and recovering normal pressure. Then, the column feeding liquid subjected to vacuum degassing is carried out at the flow rate of 0.6BV/h, and the column feeding is stopped until the effluent liquid has sweet taste;

(3) and (3) column washing and desorption: firstly, washing the column by using a hydrochloric acid aqueous solution in a subcritical state (namely the pressure in the chromatographic column is 5MPa, the temperature is 140 ℃, and the pH value is 4) at the flow rate of 2BV/h and the column washing volume of 5 BV; then using 10BV ethanol water solution with volume fraction of 0-65% to carry out continuous linear elution, and respectively collecting desorption liquid I with content lower than 70% and desorption liquid II with content not lower than 70%.

(4) Concentration and drying: concentrating the collected desorption solution by a single-effect vacuum concentrator until the content of soluble solids is 54.2 percent and 53.2 percent, and respectively obtaining 42.8g of crude product I and 133.2g of crude product II after microwave drying and crushing;

(5) column leaching: respectively and independently baking the obtained crude product I and the crude product II at the constant temperature of 200 ℃ for 30min, then loading the crude product I and the crude product II into a column chromatography column with the diameter-height ratio of 1:7, then carrying out leakage leaching by using a subcritical water solution with the temperature of 140 ℃ and the pressure of 15MPa, wherein the volume of the subcritical water is 1.5L and 4L respectively, the leakage flow rate is 0.5BV/h, and respectively collecting leakage leaching liquor to obtain the leakage leaching liquor I and the leakage leaching liquor II.

(6) Membrane filtration: respectively passing the obtained seepage leaching liquor I and seepage leaching liquor II through a 500Da nanofiltration membrane, and respectively collecting trapped fluid I and trapped fluid II;

(7) concentrating and drying: and respectively concentrating the collected trapped fluid I and the trapped fluid II by using a single-effect vacuum concentrator until the content of soluble solids is 52.9 percent and 53.6 percent, and performing microwave drying, crushing and sieving to obtain the mogroside V products with different contents.

Weighing and detecting to respectively obtain two kinds of mogroside V with different specifications, wherein the weight and the content are respectively as follows: product I: 27.6g, 80.2%; and (2) product II: 95.9g and 97.7 percent. The total yield was 92.16%.

Example 5: comparison between different Processes

Aiming at the more key influence factors in the process, the process group is set and compared in a targeted manner:

(1) comparative process 1: based on the embodiment 1, the cleaning and impurity removal in the step (3) adopt conventional water (non-subcritical state);

(2) comparative process 2: in the embodiment 1, the upper injection liquid in the step (2) is not subjected to degassing treatment;

(3) comparative process 3: in example 1, the elution mode in step (3) was changed to gradient elution, which was as follows: elution was sequentially performed with 30% and 65% ethanol by volume (flow rate 2BV/h, column volume 5BV per gradient).

(4) Comparative process 4: on the basis of the embodiment 1, the crude product in the step (4) is dried, is not baked at high temperature, is directly packed into a column and is subjected to leakage leaching;

(5) comparative process 5: based on the embodiment 1, the step (5) is changed into the conventional water (non-subcritical state) for leakage extraction when the column leakage extraction is carried out after the high-temperature baking;

the results were obtained by the same method as in example 1 and are shown in Table 1;

TABLE 1 statistical results

As can be seen from table 1, in the case of the comparative process 1, in which the subcritical acidic aqueous solution is not used for impurity removal, the weight and content of the product I and the product II are both significantly lower than those of the process of the embodiment 1 of the present invention, the same problem as that of the comparative process 1 occurs even if the solution injection in the comparative process 2 is not degassed, and at the same time, the total yield is significantly reduced; the content and the total yield of the comparison process 3 are basically equivalent to those of the invention, but the content ratio of the product II is obviously lower in weight, while the product II represents a high-quality product, and the higher the content ratio is, the better the product is in industrial production, which is obviously inferior to the process of the invention; the crude product in the comparison process 4 is not baked at high temperature, and the problem is the same as that in the comparison process 1; the control 5, which employs non-subcritical water percolation extraction, results in a reduction in overall yield of about 5%.

The foregoing is only for the purpose of understanding the method of the present invention and the core concept thereof, and it will be understood by those skilled in the art that various changes and modifications may be made without departing from the principle of the invention, and the invention also falls within the scope of the appended claims.