WO2020077970A1

WO2020077970A1 - Highly efficient stevioside mixture preparation method

Info

Publication number: WO2020077970A1
Application number: PCT/CN2019/083509
Authority: WO
Inventors: 杨文国; 谢永富; 宋云飞
Original assignee: 桂林莱茵生物科技股份有限公司
Priority date: 2018-10-16
Filing date: 2019-04-19
Publication date: 2020-04-23
Also published as: CN109456371A

Abstract

Provided in the present invention is a highly efficient stevioside mixture preparation method, the preparation method comprising the following steps: (1) placing crude stevioside into a sealed pressure-resistant system or apparatus, and adding 2-3 times the weight of the crude stevioside in ethanol at a concentration of 70%-95%, so as to dissolve into a crystallization mother liquor; (2) introducing carbon dioxide into the sealed pressure-resistant system; (3) beginning crystallization when the pressure in the sealed pressure-resistant system is 0.01 Mpa-0.5 Mpa, and the pH of the crystallization mother liquor is 4.5-5.3, crystallization time being 1-2 hours; (4) completing crystallization and filtering or centrifugating liquid, thereby obtaining pure stevioside crystals. The present invention has the following beneficial effects: compared to the prior art, the technical solution of the present invention does not require heating, and crystallization time is significantly shortened; the total glycoside content of stevia obtained by the stevioside crystallization of the present invention is as high as 99.11%, and rebaudioside A content is as high as 99.06%.

Description

Preparation method of high-efficiency stevioside mixture

Technical field

The invention relates to the field of food preparation, in particular to a method for preparing food additives.

Background technique

At present, steviol glycosides are basically extracted by heating stevia leaf raw materials with water as a solvent, and the extract is obtained by macroporous adsorption resin and ionic resin for decolorization and purification under normal pressure crystallization. However, the production cycle of atmospheric crystallization is long and the cost is high.

For example, Chinese patent application CN201210184359.X discloses a method of increasing the content of total glycosides of stevioside by crystallization. This method uses methanol, ethanol or a mixture of a certain proportion of the two to dissolve the stevioside raw material, crystallize it at 30-50 ° C for 2-10 hours, wash the crystallized solid substance after solid-liquid separation after washing with an organic solvent, and then dry it to obtain Refined stevioside products, the total glycoside content of stevioside can be more than 95%, while increasing the proportion of RA. However, the RA content of this method is below 80%, and it is impossible to achieve a breakthrough in high purity.

For example, Chinese patent application CN201210184094.3 discloses a crystallization method to increase the content of rebaudioside A in stevioside. This method dissolves the raw material of stevioside in an organic solvent, keeps the temperature at 30-50 ° C, and keeps it for 2-12 hours for crystallization; keeps stirring during the crystallization process, and the rotation speed is 20-100rpm; the above crystallization solution undergoes solid-liquid separation, and the solid substance Washing with organic solvent to remove impurities in mother liquor, drying to obtain one-time crystalline stevioside; the organic solvent is one of methanol and ethanol or a mixture thereof; through two crystallizations, the ratio of RA in the stevia sample is increased to more than 97%, and Obtain high-purity RA products. However, methanol is used as the solvent in this method, but methanol is toxic, which requires higher product impurity removal, which increases the difficulty and cost of subsequent processing.

For example, Chinese patent application CN201710007545.9 discloses a method of processing a mixture of glycosides to obtain one or more of these glycosides in a more pure form. In this method, nitrogen gas is introduced during the recrystallization of steviol glycoside to increase the pressure, thereby improving the purity of rebaudioside A to more than 96%. However, the reaction temperature of this method is as high as 100 ° C, and the crystallization time needs more than 6 hours.

There is currently a lack of a shorter production cycle and lower production cost.

Summary of the invention

In order to achieve the above object, the present invention provides a method for preparing a high-efficiency stevioside mixture. The preparation method includes the following steps:

(1) Take the crude stevioside and put it in a closed pressure-resistant system or device, add 2 to 3 times the weight of crude stevioside and the concentration of 70% to 95% ethanol to dissolve into the crystallization mother liquor;

(2) Inject carbon dioxide into the closed pressure system;

(3) When the pressure in the pressure-resistant system to be sealed is 0.01 Mpa to 0.5 Mpa, and the pH of the crystallization mother liquor is 4.5 to 5.3, crystallization starts, and the crystallization time is 1 to 2 hours;

(4) After the crystallization is completed, the liquid is separated by suction filtration or centrifugation to obtain purified stevioside crystals.

Preferably, the steviol glycoside crystals obtained in step (4) are taken, steps (1) to (3) are repeated, the standing is completed, and the liquid is separated by suction filtration or centrifugation to obtain more pure steviol glycoside crystals.

Preferably, the ethanol concentration is 80% to 90%.

Preferably, when the pressure in the pressure-resistant system to be sealed is 0.05 Mpa to 0.4 Mpa, and the pH of the crystal mother liquor is 4.65 to 5.01, crystallization begins.

Preferably, when the pressure in the pressure-resistant system to be sealed is 0.1 MPa to 0.4 MPa, and the pH of the crystallization mother liquor is 4.65 to 4.83, crystallization begins.

Preferably, when the pressure in the pressure-resistant system to be sealed is 0.2 MPa to 0.4 MPa, and the pH of the crystallization mother liquor is 4.65 to 4.77, crystallization begins.

Preferably, when the pressure in the pressure-resistant system to be sealed is 0.3 Mpa to 0.4 Mpa, and the pH of the crystal mother liquor is 4.65 to 4.71, crystallization begins.

Preferably, when the pressure in the pressure-resistant system to be sealed is 0.4 MPa and the pH of the crystal mother liquor is 4.65, crystallization begins.

Preferably, the crystallization time is 2 hours.

Preferably, the sealed pressure-resistant device is a crystallization tank.

Preferably, suction filtration under the condition of pressure ≤-0.03Mpa,

Preferably, the centrifugation is performed at a rotation speed ≥200r / min.

The invention also provides the use of carbon dioxide to increase the content of total steviol glycosides in the purified or more purified stevioside crystals during the crystallization process using crude stevioside as raw material.

The invention also provides the use of carbon dioxide to increase the content of rebaudioside A in the purified or more purified stevioside crystals during the crystallization process using crude stevioside as raw material.

The crude stevioside of the crystalline raw material used in the present invention can be obtained in the following ways: (1) Self-made: using fresh leaves of stevia leaves as raw materials, the raw materials are added with an appropriate amount of water and subjected to pulping treatment by a beating machine, followed by continuous countercurrent extraction or enzyme treatment, The resulting slurry is subjected to solid-liquid separation, and the slag is slurried again or twice or more times to perform solid-liquid separation. The method of solid-liquid separation is not limited to pressing, centrifugation, or static stratification, etc. to obtain a liquid rich in stevioside. The liquid is adsorbed and purified by the macroporous adsorption resin of the polymer of styrene or divinylbenzene skeleton and decolorized by the ion exchange resin of the polymer of styrene or acrylic skeleton to obtain the decolorized liquid or dried dry powder as the crude crystalline precursor stevioside; (2) Purchase on the market.

The method of pressurized crystallization by introducing carbon dioxide is mainly to pass carbon dioxide into the material to be crystallized and maintain a certain pressure to improve the solubility of carbon dioxide, thereby controlling the concentration of carbonic acid in the material to be crystallized to achieve the purpose of changing the acidity of the material to be crystallized and accelerating induction Stevioside crystallization reaction.

Compared with the prior art, the present invention has the following beneficial effects:

(1) Compared with the prior art, the technical solution of the present invention does not require heating,

(2) Compared with the prior art, the crystallization time of the technical solution of the present invention is significantly shortened.

(3) The content of steviol glycosides in the steviol glycoside crystals obtained by the present invention is as high as 99.11%, and the content of rebaudioside A is as high as 99.06%.

detailed description

Example 1

Take 300kg of crude stevioside raw materials (total glycoside content of 83.70%, rebaudioside A content of 52.59%) into a pressure-resistant closed crystallizing tank, add 3 parts by weight of crude stevioside, concentration is 70 % Ethanol, after dissolving completely under stirring at room temperature, close all valves connected to the atmosphere of the crystallization tank and pass carbon dioxide gas (flow rate = 20L / min) to the pressure in the tank of 0.01Mpa, so that the pH of the crystallization mother liquor is 5.22, keep the crystallization 2 After crystallization, the crystals were separated by suction at a pressure ≤-0.03Mpa to obtain 169kg of purified stevioside crystals.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 91.16%, and the content of rebaudioside A was 85.36%.

Example 2 to Example 7

The purified stevioside crystals obtained in Example 1 are used as raw materials. Specific conditions and parameters are shown in Table 1. Among them, after the crystallization of Examples 2 to 4 is completed, the crystals are separated by suction filtration at a pressure ≤-0.03Mpa. Examples 5 to 7 After the crystallization is completed, centrifugation is performed at a rotation speed ≥200r / min to separate the crystals. The remaining operation steps are the same as in Example 1.

Example 2

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of ethanol with a concentration of 70%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) until the pressure in the tank is 0.05Mpa, the pH of the crystallization mother liquor is 5.01, and the crystallization is maintained for 1 hour. After the crystallization is completed, the filter is suction filtered at a pressure ≤-0.03Mpa to separate the crystals to obtain purified Stevia glycoside crystals 7.86kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 95.45%, and the content of rebaudioside A was 91.73%.

Example 3

Take 10kg of the purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of 75% ethanol, and dissolve completely under stirring at room temperature, then close all the valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) to the pressure in the tank is 0.1Mpa, the pH of the crystallization mother liquor is 4.83, and the crystallization is maintained for 1 hour. After the crystallization is completed, suction filtration is performed at a pressure ≤-0.03Mpa to separate the crystals to obtain purified Stevia glycoside crystals 7.81kg.

After HPLC detection, the content of total stevioside in the purified stevioside crystals was 96.52%, and the content of rebaudioside A was 93.19%.

Example 4

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of ethanol with a concentration of 80%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) until the pressure in the tank is 0.2Mpa, the pH of the crystallization mother liquor is 4.77, the crystallization is maintained for 2 hours, after the crystallization is completed, the pressure is ≤-0.03Mpa to filter the crystals to separate the crystals to obtain purified Stevia glycoside crystals 7.65kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 98.23%, and the content of rebaudioside A was 95.07%.

Example 5

Take 10kg of the purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 30kg of ethanol with a concentration of 85%, and dissolve completely under stirring at room temperature, then close all the valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) to the pressure in the tank is 0.3Mpa, the pH of the crystallization mother liquor is 4.71, and the crystallization is maintained for 2 hours. After the crystallization is completed, the crystal is centrifuged at a speed of ≥200r / min to separate the crystals to obtain purified Stevia glycoside crystals 7.72kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 98.79%, and the content of rebaudioside A was 96.01%.

Example 6

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 30kg of ethanol with a concentration of 90%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) to the pressure in the tank is 0.4Mpa, the pH of the crystal mother liquor is 4.65, the crystallization is maintained for 2 hours, after the crystallization is completed, the crystal is centrifuged at a speed ≥ 200r / min to separate the crystals, and the purified Stevia glycoside crystal 8.02kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 99.11%, and the content of rebaudioside A was 99.06%.

Example 7

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 30kg of ethanol with a concentration of 95%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) to a pressure of 0.5Mpa in the tank, the pH of the crystal mother liquor is 4.61, the crystallization is maintained for 2 hours, after the crystallization is completed, the crystal is centrifuged at a speed of ≥200r / min to separate the crystals to obtain purified Stevioside crystals 8.07kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 98.72%, and the content of rebaudioside A was 95.36%.

Example 2-7 Process reference comparison and product purity comparison results are shown in Table 1.

Table 1 Example 2-7 process reference comparison and product purity comparison results

Description of comparison:

All the purified stevioside crystals obtained in Example 1 were used as raw materials. Comparative Example 1 was used to evaluate the effect of conventional crystallization operations on the content of total stevioside and rebaudioside A in crystalline products; Comparative Examples 2 to 5 were used to evaluate the Carbon dioxide into other ranges of air pressure and the corresponding pH effect on the content of total stevioside and rebaudioside A in crystalline products; Comparative examples 6-8 are used to evaluate the suitable range of air pressure or pH formed by different methods on crystalline products stevioside The effect of total glycoside and rebaudioside A content.

Comparative Example 1

The purified stevioside crystals obtained in Example 1 were used as raw materials without gas, pressure or pH adjustment, and the crystallization time was 12 hours. The rest of the operation is the same as in Example 2.

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of ethanol with a concentration of 70%, and dissolve completely under stirring at room temperature, then maintain the crystallization for 12 hours. After the crystallization is completed, the pressure is ≤- 0.03Mpa suction filtration to separate the crystals to obtain 5.05kg of purified stevioside crystals.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 91.22%, and the content of rebaudioside A was 80.53%.

Description of Comparative Examples 2 ～ 5

The purified stevioside crystals obtained in Example 1 were used as raw materials, and the specific condition parameters are shown in Table 2. The remaining operation steps are the same as in Example 2.

Comparative Example 2

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of ethanol with a concentration of 70%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) until the pressure in the tank is 0.55Mpa, the pH of the crystallization mother liquor is 4.45, and the crystallization is maintained for 2 hours. After the crystallization is completed, the pressure is ≤-0.03Mpa to separate the crystals to obtain purified Stevia glycoside crystals 8.15kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 94.17%, and the content of rebaudioside A was 92.39%.

Comparative Example 3

Take 10kg of the purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of 75% ethanol, and dissolve completely under stirring at room temperature, then close all the valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) until the pressure in the tank is 0.6Mpa, the pH of the crystallization mother liquor is 4.41, and the crystallization is maintained for 2 hours. After the crystallization, the crystal is separated by suction at a pressure ≤-0.03Mpa to obtain the purified Stevioside crystals 8.21kg.

After HPLC detection, the content of total stevioside in purified stevioside crystals was 93.16%, and the content of rebaudioside A was 90.74%.

Comparative Example 4

Take 10kg of the purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 30kg of ethanol with a concentration of 85%, and dissolve completely under stirring at room temperature, then close all the valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) to a pressure of 0.8Mpa in the tank, the pH of the crystal mother liquor is 4.40, keep crystallization for 2 hours, after the crystallization is completed, suction filtration at a pressure ≤-0.03Mpa to separate the crystals to obtain purified Stevioside crystals 8.35kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 94.01%, and the content of rebaudioside A was 91.55%.

Comparative Example 5

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 30kg of ethanol with a concentration of 95%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Carbon dioxide gas (flow rate = 20L / min) to a pressure of 0.9Mpa in the tank, the pH of the crystal mother liquor is 4.38, maintain crystallization for 2 hours, after the crystallization is completed, suction filtration at a pressure ≤-0.03Mpa to separate the crystals to obtain purified Stevia glycoside crystals 8.49kg.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 93.72%, and the content of rebaudioside A was 90.11%.

Comparative Example 6

The purified stevioside crystals obtained in Example 1 were used as raw materials without carbon dioxide, but with nitrogen, so that the pressure was 0.3 MPa; a carbonic acid solution was added, so that the pH was 4.76, and the crystallization time was 2 hours. The rest of the operation is the same as in Example 2.

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of ethanol with a concentration of 70%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Nitrogen (flow rate = 20L / min) to the pressure in the tank is 0.3Mpa, and the carbonic acid solution is added to make the pH of the crystallization mother liquid is 4.76, and the crystallization is maintained for 2 hours. After the crystallization is completed, the pressure is less than -0.03Mpa to filter out to separate the crystal To obtain 6.55 kg of purified stevioside crystals.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 94.14%, and the content of rebaudioside A was 92.77%.

Comparative Example 7

The purified stevioside crystals obtained in Example 1 were used as raw materials without carbon dioxide or nitrogen, so that the pressure was 0.1 Mpa, pH was not adjusted, and the crystallization time was 2 hours. The rest of the operation is the same as in Example 2.

Take 10kg of purified stevioside crystals obtained in Example 1 into a pressure-resistant sealed crystallization tank, add 20kg of ethanol with a concentration of 70%, and dissolve completely under stirring at room temperature, then close all valves connected to the atmosphere of the crystallization tank and pass into Nitrogen (flow rate = 20L / min) to the pressure in the tank of 0.1Mpa, keep the crystallization for 2 hours, after the crystallization is completed, the pressure is ≤-0.03Mpa with suction filtration to separate the crystals to obtain 6.39kg of purified stevioside crystals.

After HPLC detection, the content of total steviol glycosides in the purified stevioside crystals was 92.35%, and the content of rebaudioside A was 90.76%.

Comparative Example 8

The purified stevioside crystals obtained in Example 1 were used as raw materials without gas flow; a carbonic acid solution was added to make the pH 4.88 and the crystallization time 3 hours. The rest of the operation is the same as in Example 2.

10kg of the purified stevioside crystals obtained in Example 1 was put into a pressure-resistant sealed crystallization tank, 20kg of ethanol with a concentration of 70% was added, and the solution was completely dissolved under stirring at room temperature, and then a carbonic acid solution was added to make the pH of the crystal mother liquor 4.88 The crystallization is maintained for 3 hours. After the crystallization is completed, suction filtration is performed at a pressure ≤-0.03Mpa to separate the crystals to obtain 7.08 kg of purified stevioside crystals.

After HPLC detection, the content of total stevioside in the purified stevioside crystals was 93.82%, and the content of rebaudioside A was 91.93%.

The comparison results of product purity of Comparative Examples 1-8 are shown in Table 2.

Table 2 Comparative examples 1-8 Process reference comparison and product purity comparison results

We can know from the experiment:

1. It can be known from Examples 2 to 7 that after the introduction of carbon dioxide, the air pressure of the system has a certain corresponding relationship with the pH, that is, the higher the air pressure, the lower the pH; at the same time, as the pressure increases, the pH decreases, the product stevioside The purity of total glycosides and rebaudioside A gradually increased; when the pressure was increased to 0.4Mpa and the pH was 4.65, the purity of the total stevioside and rebaudioside A of the resulting product was as high as 99.11% and 99.06%, respectively; when the pressure When it exceeds 0.4Mpa, the purity of total steviol glycosides and rebaudioside A of the resulting products will show a downward trend.

2. From Comparative Example 1, it can be known that the purity of the total stevioside and rebaudioside A of the obtained product is lower than that of Examples 2 to 7 of the present invention by using a common crystallization method without adjusting air pressure or pH.

3. From Comparative Examples 2 to 5, it can be seen that after using the pressure range higher than that defined in Examples 2 to 7 and lower than the pH range defined in Examples 2 to 7, the purity of the total stevioside and rebaudioside A of the resulting product All are lower than the embodiments 2-7 of the present invention.

4. From Comparative Example 8, it is known that nitrogen gas is used to form the same pressure range as Examples 2-7, and carbonic acid solution is used to form the same pH range as Examples 2-7. The total stevioside and rebaudioside of the resulting product The purity of A is lower than that of Examples 2-7 of the present invention.

5. It is known from Comparative Example 9 that nitrogen gas is used to form the same pressure range as in Examples 2-7, and the resulting products have a lower total purity of steviol glycosides and rebaudioside A than Examples 2-7 of the present invention.

6. It can be known from Comparative Example 10 that the carbonic acid solution is used to form the same pH range as in Examples 2-7, and the purity of the total stevioside and rebaudioside A of the obtained product is lower than that of Examples 2-7 of the present invention.

The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and illustration. These descriptions are not intended to limit the invention to the disclosed precise form, and it is clear that many changes and modifications can be made according to the above teachings, for example, the method can also be applied to the purification of substances with a chemical structure similar to stevioside. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can implement and utilize various exemplary embodiments of the present invention and various Choice and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

A high-efficiency stevioside mixture preparation method, the preparation method includes the following steps:

(1) Take the crude stevioside and put it in a closed pressure-resistant system or device, add 2 to 3 times the weight of crude stevioside and the concentration of 70% to 95% ethanol to dissolve into the crystallization mother liquor;

(2) Inject carbon dioxide into the closed pressure system;

(3) When the pressure in the pressure-resistant system to be sealed is 0.01 Mpa to 0.5 Mpa, and the pH of the crystallization mother liquor is 4.5 to 5.3, crystallization starts, and the crystallization time is 1 to 2 hours;

(4) After the crystallization is completed, the liquid is separated by suction filtration or centrifugation to obtain purified stevioside crystals.
The method according to claim 1, characterized in that the stevioside crystals obtained in step (4) are taken, steps (1) to (3) are repeated, and after standing still, the liquid is separated by suction filtration or centrifugation to obtain a more pure Stevioside crystals.
The method according to claim 1 or 2, wherein the ethanol concentration is 80% to 90%.
The method according to claim 1 or 2, characterized in that the crystallization starts when the pressure in the pressure-resistant system to be sealed is 0.05 MPa to 0.4 MPa and the pH of the crystallization mother liquor is 4.65 to 5.01.
The method according to claim 1 or 2, characterized in that crystallization starts when the pressure in the pressure-resistant system to be sealed is 0.1 MPa to 0.4 MPa and the pH of the crystallization mother liquor is 4.65 to 4.83.
The method according to claim 1 or 2, characterized in that the crystallization starts when the pressure in the pressure-resistant system to be sealed is 0.2 MPa to 0.4 MPa and the pH of the crystallization mother liquor is 4.65 to 4.77.
The method according to claim 1 or 2, characterized in that crystallization starts when the pressure in the pressure-resistant system to be sealed is 0.3 MPa to 0.4 MPa and the pH of the crystallization mother liquor is 4.65 to 4.71.
The method according to claim 1 or 2, characterized in that the crystallization starts when the pressure in the pressure-resistant system to be sealed is 0.4 MPa and the pH of the crystallization mother liquor is 4.65.
The method according to claim 1 or 2, wherein the crystallization time is 2 hours.
The method according to claim 1 or 2, wherein the sealed pressure-resistant device is a crystallization tank.
The method according to claim 1 or 2, characterized in that suction filtration is performed under the condition of pressure ≤ -0.03Mpa.
The method according to claim 1 or 2, wherein the centrifugation is performed at a rotation speed ≥200r / min.
A use of carbon dioxide to increase the content of total steviol glycosides in the purified or more purified stevioside crystals during the crystallization process using crude stevioside as raw material.
A use of carbon dioxide to increase the content of rebaudioside A in purified or more purified stevioside crystals during the crystallization process using crude stevioside as raw material.