A method for preparing steviol glycoside single components using low total glycoside mother liquor sugar

Abstract

The application belongs to the technical field of steviol glycoside production, and discloses a method for preparing steviol glycoside single components by using low total glycoside mother liquor sugar, which comprises the following steps: dissolving the low total glycoside mother liquor sugar in 80-95% methanol solution, crystallizing, filtering to obtain mother liquor and filter cake, treating the filter cake with 40-50% methanol solution, stirring and crystallizing, filtering to obtain mother liquor and filter cake, drying the filter cake to obtain pure rebaudioside A; using macroporous adsorption resin to separate the two mother liquors obtained in the previous step, using 30% ethanol solution to separate the glycosides adsorbed in the macroporous adsorption resin, playing a separating role, using 50% ethanol solution added with 1‰ oil tea saponin to resolve the macroporous adsorption resin, crystallizing and recrystallizing the resolution liquid, drying the filter cake to obtain rebaudioside C, and combining the two mother liquors obtained, removing impurities, and using high-pressure chromatography to collect resolution liquid containing rebaudioside F, and drying the resolution liquid to obtain rebaudioside F. The method is simple and effective, and greatly improves the reutilization rate of low total glycoside mother liquor sugar.

Description

A method for preparing steviol glycoside single components using low total glycoside mother liquor sugar Technical Field

[0001] This invention belongs to the field of steviol glycoside production technology, specifically relating to a method for preparing steviol glycoside single components using low total glycoside mother liquor sugar. Background Technology

[0002] Steviosides are low-calorie, high-intensity natural sweeteners extracted from stevia leaves. Their sweetness is 200-300 times that of sucrose, while their calories are only about 1 / 250th that of sucrose. They contain various tetracyclic diterpenoid monomers, all sharing the same aglycone—stevioside. Based on the different aglycones linked at C13 and C19 positions, they can be classified into steviol glycosides, steviol A, B, C, D, E, dulcoside, stevioside, and raspberry glycoside. Among these monomers, steviol glycosides and steviol A are the most abundant, accounting for 5%-9.5% and 2%-4.5% of the leaf dry weight, respectively, with sweetness levels 300 and 450 times that of sucrose, respectively. Studies have shown that steviol glycosides can inhibit hyperglycemia and hypertension, and have anti-inflammatory, anti-tumor, antidiarrheal, diuretic, and immune-regulating effects. They also have certain adjuvant therapeutic effects on obesity, hypertension, and heart disease, and have no toxic side effects. They can be used as a sucrose substitute and are a functional sweetener with significant development potential.

[0003] Currently, the main extraction methods for steviol glycosides include hot water extraction, decoction, and reflux extraction. However, regardless of the method used, the final step requires crystallization and refining after obtaining crude steviol glycosides. The mother liquor generated during the initial crystallization process is generally reused in the raw materials for re-extraction. However, the mother liquor generated in the final crystallization step is collectively referred to as low total glycoside mother liquor sugar because of its low total glycoside content. Reusing this mother liquor will affect the overall extraction yield, quality, and crystallization efficiency, so it will be treated as waste. The treatment of this waste is difficult and costly, and it also leads to material waste. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing steviol glycoside single components using low total glycoside mother liquor, which overcomes the defects in the prior art, utilizes waste materials to prepare steviol glycoside single components, reduces the production cost of steviol glycoside, and increases economic benefits.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for preparing steviol glycoside single components using low total glycoside mother liquor sugar includes the following steps:

[0007] a. Dilute the low total glycoside mother liquor sugar (solid powder) with a methanol solution (mixture of methanol and water) at a weight-to-volume ratio (g:ml) of 80-95%. Stir at 100-200 rpm for 20-30 h at room temperature until crystallization occurs. Filter to obtain filter cake and crystallization mother liquor. After drying the filter cake, add 4-7 times the weight-to-volume ratio of methanol solution with a mass concentration of 40-50%. Stir at 100-200 rpm for 20-30 h at room temperature to recrystallize. Filter to obtain filter cake and recrystallization mother liquor. Collect the filter cake and dry it to obtain the Rebaudioside A product.

[0008] b. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step a to obtain a combined solution. Evaporate the combined solution to dryness, make it into powder, and then add water to make a sugar solution with a mass concentration of 10-20%. Load the solution into the macroporous adsorption resin at a flow rate of 0.1-1 BV / h at a sample loading rate of 5-10% (referring to the resin volume percentage). Then, first use two column bed volumes (100 ml resin corresponds to 200 ml 30% ethanol solution) of a 30% ethanol solution (ethanol and water mixture) for elution (this will not elute the effective components, but will separate the glycosides). Do not retain the 30% ethanol solution eluent. Then, weigh 1‰ of the resin volume of tea oil saponins and dissolve them in two column bed volumes of a 50% ethanol solution (used to enrich rebaudioside C and rebaudioside F). Use this as the eluent for elution and collect the eluent. Evaporate the eluent to dryness to make it into powder, and then add the powder weight... A 10% methanol solution with a mass concentration of 2-3 times the volume ratio is stirred at 100-200 rpm for 20-30 hours at room temperature to crystallize. The mixture is filtered to obtain a filter cake and a mother liquor for crystallization. The filter cake is dried, and the dried filter cake is dissolved in a 10% methanol solution with a mass concentration of 7-10 times the weight volume ratio. The mixture is stirred at 100-200 rpm for 20-30 hours at room temperature to recrystallize. The mixture is filtered to obtain a filter cake and a mother liquor for recrystallization. The filter cake is collected and dried to obtain the product riboside C.

[0009] c. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step b to obtain a combined solution. Evaporate the combined solution to dryness to make sugar powder. Add water to make a sugar solution with a mass concentration of 10-20%. Add 1% activated carbon by weight of sugar powder to the sugar solution for adsorption. Then filter out the activated carbon. Evaporate the clear liquid obtained from the filtration to dryness and then dissolve it in ethanol with a mass concentration of 80% at a weight-volume ratio of 1:10. Pass the solution through a high-pressure chromatographic column and collect the eluent containing the riboside F segment (see peak 2 marked in Figure 1). After drying, obtain the riboside F product.

[0010] Preferably, in step a, the methanol solution added in twice the amount has a mass concentration of 85%, the stirring speed is 150 rpm for both times, 5 times the weight of the methanol solution with a mass concentration of 45% is added to the filter cake, and the stirring time is 25 hours for both times.

[0011] Preferably, in step a, the filtration is carried out using filter media with a pore size of 5-10 μm, the filter cake is dried in a constant temperature drying oven at 80-110°C, and the filtrate is reserved for later use.

[0012] Preferably, in step b, the combined liquid of the crystallization mother liquor and the recrystallization mother liquor is evaporated to dryness and then dissolved in water to obtain a sugar solution with a solid content of 15%. The sample loading amount of the sugar solution is 8%, the flow rate is 0.8 BV / h, and the macroporous adsorption resin is a non-polar macroporous adsorption resin or a medium-polar macroporous adsorption resin. During crystallization, a methanol solution with a powder weight-to-volume ratio of 2.5 times is added, and during recrystallization, a methanol solution with a powder weight-to-volume ratio of 8.5 times is added. The stirring speed is 150 rpm and the stirring time is 25 h for both crystallization and recrystallization. Filtration is carried out using filter media with a pore size of 5-10 μm, and the filter cake is dried in a dryer at 50°C.

[0013] Furthermore, in step b, the solid content of the sugar solution obtained by evaporating the combined liquid to water is 12%, the macroporous adsorption resin is LX-T81 type steviol glycoside separation and purification resin, and the evaporation treatment is carried out by rotary evaporator (speed 10-50 r / min, temperature 70-95℃).

[0014] Preferably, the activated carbon addition ratio in step c is 2%, and the evaporation treatment is carried out by rotary evaporator (speed 10-50 r / min, temperature 70-95℃).

[0015] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0016] This invention first dissolves the low total glycoside mother liquor sugar in an 80-95% methanol solution, stirs to crystallize, and filters to obtain mother liquor and filter cake. The filter cake is then treated with a 40-50% methanol solution, stirred to crystallize, and filtered again to obtain mother liquor and filter cake. After drying the filter cake, pure ribobadiin A is obtained. The mother liquors obtained from the previous two treatments are then processed with a macroporous adsorption resin, and then the adsorbed glycosides in the macroporous adsorption resin are separated using a 30% ethanol solution. Finally, 1-5‰ of camellia saponins are added (to enrich ribobadiin C and ribobadiin F). A 50% ethanol solution was used to elute the macroporous adsorption resin. The eluent was then crystallized and recrystallized, and the resulting filter cake, after drying, yielded ribobadiin C. The two mother liquors were combined, and impurities were first adsorbed off using activated carbon. Then, the eluent containing ribobadiin F was collected using a high-pressure chromatography column and dried to obtain ribobadiin F. This process effectively separates ribobadiin A, ribobadiin C, and ribobadiin F from the low total glycoside mother liquor, yielding pure stevia monoglycosides and significantly improving the reuse rate of the low total glycoside mother liquor. This method is simple, effective, and energy-saving, making it worthy of promotion and application in the stevia industry. Attached Figure Description

[0017] Figure 1 is a chromatogram of high-pressure preparation in step c of Example 1 of the present invention;

[0018] Among them, the peak that flowed out 5 minutes ago was the solvent peak, and the peaks that flowed out from 5 to 10 minutes ago were peak 1, peak 2, and peak 3, respectively. Peak 1 is ribobandi glycoside A, peak 2 is ribobandi glycoside F, and peak 3 is ribobandi glycoside C. Detailed Implementation

[0019] The present invention will be further illustrated below with reference to the embodiments.

[0020] Example 1

[0021] a. Accurately weigh 100g of the low total glycoside mother liquor (3.8% moisture, 31.4% riboside A, 2% steviol glycosides, 24.1% riboside C, 5.2% riboside F, and 4.7% other glycosides), add 200ml of 95% methanol solution, stir at 200rpm at room temperature for 20h to crystallize, filter to obtain 55g of filter cake, and obtain 98ml of crystallization mother liquor; dry the filter cake and grind it into powder, add 385ml of 40% methanol solution (7 times the weight of the filter cake), stir at 200rpm at room temperature for 20h to recrystallize, filter and collect the filter cake, and dry it at 105℃ to obtain 28g of riboside A product with a purity of 99.2%, and obtain 382ml of recrystallization filtrate;

[0022] b. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step a to obtain 480 ml of combined solution. Evaporate the combined solution to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 72 g of dried stevia powder. Then add water to prepare a 20% (w / w) sugar solution. Load the solution at 5% of the resin volume (the resin treatment in this step and subsequent steps will be calculated based on the solution volume used for each column pass until all the sugar powder has been processed). Enter the macroporous adsorption resin (1 L volume) at a flow rate of 0.1 BV / h (100 ml / h) for adsorption and discard the effluent. Then, first use two column volumes (2 L) of 30% (w / w) ethanol solution for elution. Do not retain the 30% ethanol solution eluent. Then, dissolve 1 g of camellia saponin in 50% (w / w) ethanol solution and load it onto the column. Then, use two times (2 L) of 50% (w / w) ethanol solution for elution (the elution rate for both 30% and 50% is 1 L / h). Collect the eluent.

[0023] The above-mentioned eluent was evaporated to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 60 g of stevia powder. This powder was then added to 120 ml of a 10% methanol solution (twice the volume of the eluent). The mixture was stirred at 100 rpm for 30 h at room temperature to allow crystallization. Filtering yielded 34 g of filter cake (wet weight) and 118 ml of crystallization mother liquor. The filter cake was dried to obtain 30 g of stevia. This stevia powder was then added to 210 ml of a 10% methanol solution (twice the volume of the eluent). The mixture was stirred at 100 rpm for 30 h at room temperature to allow recrystallization. The filter cake was collected by filtration and dried at 85 °C to obtain 22 g of 99.5% pure Rebaudioside C product and 202 ml of recrystallization mother liquor.

[0024] c. Combine the crystallization mother liquor and recrystallization mother liquor from step b to obtain 320 ml of combined liquid. Evaporate to dryness using a rotary evaporator (50 r / min, 70 °C) to obtain 43 g of stevia powder. Add 1% (0.43 g) of activated carbon for adsorption (the purpose of activated carbon adsorption in this step is to effectively remove pigments and some impurities). Then filter out the activated carbon. Evaporate the filtered clear liquid to dryness using a rotary evaporator (50 r / min, 70 °C) to obtain 41 g of stevia powder. Dissolve the powder in 410 ml of 80% ethanol. Load the sample at 0.5% onto a high-pressure chromatographic column. Observe the chromatogram and accurately collect the eluent containing the riboside F segment (see peak 2 segment marked in Figure 1) within the specified time period. After drying using a rotary evaporator (50 r / min, 70 °C), obtain 4.7 g of riboside F product with a purity of 96.2%.

[0025] Summarize:

[0026] 100g of low total glycoside mother liquor was effectively enriched and purified to obtain 28g of riboside A (purity 99.2%), 22g of riboside C (purity 99.5%), and 4.7g of riboside F (purity 96.2%). The effective yield of riboside A was 88.5%, the effective yield of riboside C was 90.8%, and the effective yield of riboside F was 86.95%.

[0027] Example 2

[0028] a. Accurately weigh 200g of low total glycoside mother liquor (3.8% moisture, 31.4% riboside A, 2% steviol glycosides, 24.1% riboside C, 5.2% riboside F, and 4.7% other glycosides), add 400ml of 85% methanol solution, stir at 100rpm at room temperature for 30h to crystallize, filter to obtain 124g of filter cake, and obtain 395ml of crystallization filtrate; evaporate the filter cake to obtain 120g of steviol powder, add 480ml of 50% methanol solution (4 times the weight of the filter cake), stir at 100rpm at room temperature for 30h to recrystallize, filter to collect the filter cake, and dry at 90℃ to obtain 60g of riboside A product with a purity of 99.7%, and obtain 476ml of recrystallization filtrate;

[0029] b. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step a to obtain 871 ml of combined solution. Evaporate the combined solution to dryness using a rotary evaporator (30 r / min, 85 °C) to obtain 138 g of dried stevia powder. Then add water to prepare a 12% (w / w) sugar solution. Load the solution at 8% of the resin volume (the resin treatment in this step and subsequent steps will be calculated based on the solution volume used for each column pass until all the sugar powder has been processed). Then, enter the macroporous adsorption resin (volume 1 L) at a flow rate of 0.5 BV / h (500 ml / h) for adsorption and discard the effluent. First, use two column volumes (2 L) of 30% (w / w) ethanol solution for elution. Do not retain the elution solution. Then, dissolve 1 g of camellia saponin in 50% (w / w) ethanol solution and load it onto the column. Then, use two column volumes (2 L) of 50% (w / w) ethanol solution for elution (the elution rate for both 30% and 50% elution is 1 L / h). Collect the elution solution.

[0030] The above-mentioned eluent was evaporated to dryness using a rotary evaporator (30 r / min, 85 °C) to obtain 105 g of stevia powder. This powder was then added to 210 ml of a 10% methanol solution (twice the volume of the eluent). The mixture was stirred at 200 rpm for 20 h at room temperature to allow crystallization. Filtering yielded 66 g of filter cake (wet weight) and 205 ml of crystallization mother liquor. The filter cake was dried to obtain 63 g of stevia. This 63 g of stevia was then added to 441 ml of a 10% methanol solution (twice the volume of the eluent). The mixture was stirred at 200 rpm for 20 h at room temperature to allow recrystallization. The filter cake was collected by filtration and dried at 95 °C to obtain 44 g of riboside C product with a purity of 99.3%, and 438 ml of recrystallization mother liquor was obtained.

[0031] c. Combine the crystallization mother liquor and recrystallization mother liquor from step b to obtain 643 ml of combined liquid. Evaporate to dryness using a rotary evaporator (30 r / min, 85 °C) to obtain 60 g of stevia powder. Add 1% (0.6 g) of activated carbon for adsorption, and then filter out the activated carbon (the purpose of this activated carbon adsorption step is to effectively remove pigments and some impurities). Evaporate the filtered clear liquid to dryness using a rotary evaporator (30 r / min, 85 °C) to obtain 58 g of stevia powder. Dissolve the powder in 580 ml of 80% ethanol. Load the sample at 0.5% onto a high-pressure chromatographic column, observe the chromatogram, and accurately collect the eluent containing riboside F (see peak 2 in Figure 1) within the specified time period. Dry the eluent using a rotary evaporator (30 r / min, 85 °C) to obtain 10 g of riboside F product with a purity of 97%.

[0032] Summarize:

[0033] 200g of low total glycoside mother liquor was effectively enriched and purified to obtain 60g of riboside A (purity 99.7%), 44g of riboside C (purity 99.3%), and 10g of riboside F (purity 97%). The effective yield of riboside A was 95.3%, the effective yield of riboside C was 90.6%, and the effective yield of riboside F was 93.3%.

[0034] Example 3

[0035] a. Accurately weigh 150g of low total glycoside mother liquor (3.8% moisture, 31.4% riboside A, 2% steviol glycosides, 24.1% riboside C, 5.2% riboside F, and 4.7% other glycosides), add 450ml of 90% methanol solution, stir at 120rpm at room temperature for 24h to crystallize, filter to obtain 80g of filter cake, and obtain 447ml of crystallization filtrate; evaporate the filter cake to obtain 78g of steviol powder, add 390ml of 45% methanol solution (5 times the weight of the filter cake), stir at 100rpm at room temperature for 30h to recrystallize, filter to collect the filter cake, and dry at 98℃ to obtain 42g of riboside A product with a purity of 99.4%, and obtain 388ml of recrystallization filtrate;

[0036] b. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step a to obtain 835 ml of combined solution. Evaporate the combined solution to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 107 g of dried stevia powder. Then add water to prepare a 10% (w / w) sugar solution. Load the solution at 10% of the resin volume (the resin treatment in this step and subsequent steps will be calculated based on the solution volume used for each column pass until all the sugar powder has been processed). Then, enter the macroporous adsorption resin (volume 1 L) at a flow rate of 0.8 BV / h (800 ml / h) for adsorption and discard the effluent. Then, first, use two column volumes (2 L) of 30% (w / w) ethanol solution for elution. Do not retain the 30% ethanol solution eluent. Then, dissolve 1 g of camellia saponin in 50% (w / w) ethanol solution and load it onto the column. Then, use two column volumes (2 L) of 50% (w / w) ethanol solution for elution (the elution rate for both 30% and 50% ethanol solutions is 1 L / h). Collect the eluent.

[0037] The above-mentioned eluent was evaporated to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 82 g of stevia powder. This powder was then added to 164 ml of a 10% methanol solution (twice the volume of the eluent). The mixture was stirred at 150 rpm for 25 h at room temperature to allow crystallization. Filtering yielded 51 g of filter cake (wet weight) and 161 ml of crystallization mother liquor. The filter cake was dried to obtain 50 g of stevia. This 50 g of stevia powder was then added to 350 ml of a 10% methanol solution (seven times the volume of the eluent). The mixture was stirred at 150 rpm for 25 h at room temperature to allow recrystallization. The filter cake was collected by filtration and dried at 95 °C to obtain 35 g of a product with a purity of 99.4% (referred to as riboside C). 344 ml of recrystallization mother liquor was also obtained.

[0038] c. Combine the crystallization mother liquor and recrystallization mother liquor from step b to obtain 505 ml of combined liquid. Evaporate to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 65 g of stevia powder. Add 1% (0.65 g) of activated carbon for adsorption, and then filter out the activated carbon (the purpose of this activated carbon adsorption step is to effectively remove pigments and some impurities). Evaporate the filtered clear liquid to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 62 g of stevia powder. Dissolve the powder in 620 ml of 80% ethanol. Load the sample at 0.5% onto a high-pressure chromatographic column (column volume 1 L). Observe the chromatogram and accurately collect the eluent containing the peak area region of ribobandiside F. Evaporate to dryness using a rotary evaporator (10 r / min, 95 °C) to obtain 7.6 g of ribobandiside F product with a purity of 95.8%.

[0039] Summarize:

[0040] 150g of low total glycoside mother liquor was effectively enriched and purified to obtain 42g of riboside A (99.4%), 35g of riboside C (99.4%), and 7.6g of riboside F (95.8%). The effective yield of riboside A was 88.6%, the effective yield of riboside C was 96.23%, and the effective yield of riboside F was 93.3%.

[0041] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for preparing steviol glycosides from a low total glycoside mother liquor, characterized in that, Includes the following steps: a. Dilute the low total glycoside mother liquor with twice the weight-volume ratio of 80-95% methanol solution. Stir at 100-200 rpm for 20-30 hours at room temperature until crystallization. Filter to obtain filter cake and crystallization mother liquor. Dry the filter cake and add 4-7 times the weight-volume ratio of 40-50% methanol solution. Stir at 100-200 rpm for 20-30 hours at room temperature for recrystallization. Filter to obtain filter cake and recrystallization mother liquor. Collect the filter cake and dry it to obtain riboside A product; b. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step a to obtain a combined solution. Evaporate the combined solution to dryness, make it into powder, and then add water to make a sugar solution with a mass concentration of 10-20%. Load the solution into a macroporous adsorption resin at a flow rate of 0.1-1 BV / h at a sample loading rate of 5-10%. Then, first use twice the weight-volume ratio of 80-95% methanol solution to dilute the total glycoside mother liquor. The column bed volume was analyzed with a 30% ethanol solution, and the 30% ethanol solution was not retained. Then, 1‰ of the resin volume of camellia saponin was weighed and dissolved in a 50% ethanol solution with a mass concentration of 2 times the column bed volume as the eluent. The eluent was collected and evaporated to dryness to make powder. Then, 2-3 times the weight-volume ratio of the powder was added to a 10% methanol solution with a mass concentration of 10%. The mixture was stirred at 100-200 rpm for 20-30 hours at room temperature to crystallize. The filter cake and crystallization mother liquor were obtained by filtration. The filter cake was dried and dissolved in a 10% methanol solution with a mass concentration of 10% with a weight-volume ratio of 7-10. The mixture was stirred at 100-200 rpm for 20-30 hours at room temperature to recrystallize. The filter cake and recrystallization mother liquor were obtained by filtration. The filter cake was collected and dried to obtain the product ribaodi glycoside C. c. Combine the crystallization mother liquor and recrystallization mother liquor obtained in step b to obtain a combined solution. Evaporate the combined solution to dryness to make sugar powder. Add water to make a sugar solution with a mass concentration of 10-20%. Add 1% of the sugar powder weight of activated carbon to the sugar solution for adsorption. Then filter out the activated carbon. Evaporate the clear liquid obtained from the filtration to dryness. Dissolve it in ethanol with a mass concentration of 80% at a weight-volume ratio of 1:

10. Pass the solution through a high-pressure chromatography column and collect the eluent containing the riboside F segment. After drying, obtain the riboside F product.

2. The method for preparing steviol glycoside single components using low total glycoside mother liquor as described in claim 1, characterized in that: In step a, the methanol solution added in twice the amount has a mass concentration of 85%, the stirring speed is 150 rpm in both steps, 5 times the weight of the methanol solution with a mass concentration of 45% is added to the filter cake, and the stirring time is 25 hours in both steps.

3. The method for preparing steviol glycoside single components using low total glycoside mother liquor as described in claim 1, characterized in that: In step a, the filtration is carried out using filter media with a pore size of 5-10 μm, the filter cake is dried in a constant temperature drying oven at 80-110℃, and the filtrate is reserved for later use.

4. The method for preparing steviol glycoside single components using low total glycoside mother liquor as described in claim 1, characterized in that: In step b, the combined liquid of the crystallization mother liquor and recrystallization mother liquor is evaporated to dryness and then dissolved in water to obtain a sugar solution with a solid content of 15%. The sample loading amount of the sugar solution is 8%, the flow rate is 0.8 BV / h, and the macroporous adsorption resin is a non-polar macroporous adsorption resin or a medium-polar macroporous adsorption resin. During crystallization, a methanol solution with a powder weight-volume ratio of 2.5 times is added, and during recrystallization, a methanol solution with a powder weight-volume ratio of 8.5 times is added. The stirring speed is 150 rpm and the stirring time is 25 h for both crystallization and recrystallization. Filtration is carried out using filter media with a pore size of 5-10 μm, and the filter cake is dried in a dryer at 50°C.

5. The method for preparing steviol glycoside single components using low total glycoside mother liquor as described in claim 4, characterized in that: In step b, the solid content of the sugar solution obtained by evaporating the combined liquid to water is 12%, and the macroporous adsorption resin is LX-T81 type steviol glycoside separation and purification resin; the evaporation treatment is carried out by rotary evaporator at a speed of 10-50 r / min and a temperature of 70-95℃.

6. The method for preparing steviol glycoside single components using low total glycoside mother liquor as described in claim 1, characterized in that: In step c, the evaporation process is carried out using a rotary evaporator at a speed of 10–50 r / min and a temperature of 70–95 °C.

Images