A process for preparing rebaudioside B using stevia mother liquor saccharide

Abstract

This invention discloses a process for preparing rebaudine B using stevia mother liquor saccharide, relating to the field of rebaudine B preparation technology, to solve the technical problems of complex preparation processes, harsh process conditions, and high preparation costs in existing rebaudine B preparation techniques. The process includes: passing a solution of stevia mother liquor saccharide through a macroporous adsorption resin column, so that rebaudine B and other stevia glycosides in the solution are adsorbed by the macroporous adsorption resin; using an alkaline solution to elute the rebaudine B adsorbed by the macroporous adsorption resin, obtaining a first eluent containing rebaudine B; adding an acid solution to the first eluent to adjust the pH of the first eluent to 2.5–3.5, and crystallizing the first eluent to obtain rebaudine B. This invention provides a process for preparing rebaudine B using stevia mother liquor saccharide.

Description

Technical Field

[0001] This invention relates to the field of rebaudine B preparation technology, and in particular to a process for preparing rebaudine B using stevia mother liquor saccharide. Background Technology

[0002] Stevia glycosides are a novel natural sweetener extracted from the leaves of Stevia rebaudiana, a perennial herbaceous plant belonging to the Asteraceae family. Characterized by high sweetness and low calories, they are an ideal sweetener to replace sucrose. Currently, many stevia producers inevitably generate a portion of stevia mother liquor after producing the main products, rebaudioside A and steviol glycosides. This mother liquor has low total glycoside content, poor taste, and low economic value. However, rebaudioside B can be significantly enriched in the mother liquor, resulting in a product with good taste and high economic value. Therefore, how to efficiently recover rebaudioside B from the mother liquor has become an urgent problem for stevia producers.

[0003] Existing technologies for preparing rebaudioside B mainly use rebaudioside A, rebaudioside D, and rebaudioside J as reaction substrates, and obtain the product through high-temperature pyrolysis. The specific steps include: 1) Feeding: Add 2-15 L of purified water per 1 kg of reaction substrate and stir thoroughly; 2) High-temperature pyrolysis: Heat the dissolved material to 110-180℃ for pyrolysis and maintain the temperature for at least 1 hour until pyrolysis is complete; 3) Filtration: Keep the pyrolysis liquid stirred, cool it to 20-40℃ for crystallization, and filter; 4) Washing: Wash the filter cake obtained after filtration with purified water at 20-80℃ until the pH of the washing liquid is 5-7, then stop washing and dry to obtain crude rebaudioside B filter cake; 5) Purification: Dissolve the crude rebaudioside B filter cake and further purify it to obtain high-quality rebaudioside B. The above-mentioned technical solutions have several drawbacks. First, the preparation process of rebaudioside B is complex and requires stringent conditions. Second, the use of rebaudioside A, D, and J as reactants results in high preparation costs, limiting the large-scale production of rebaudioside B. Therefore, a new method for preparing rebaudioside B is urgently needed to solve these problems. Summary of the Invention

[0004] To address the technical problems of complex preparation processes, demanding process conditions, and high costs in the existing methods for preparing rebaudioside B, this invention provides a process for preparing rebaudioside B using stevia mother liquor saccharide. In view of this, this invention achieves this through the following scheme.

[0005] In a first aspect, the present invention provides a process for preparing rebaudioside B using stevia mother liquor saccharide, comprising:

[0006] The solution of stevia mother liquor glycosides is passed through a macroporous adsorption resin column, so that rebaudioside B and other stevia glycosides in the solution are adsorbed by the macroporous adsorption resin.

[0007] The rebaudioside B adsorbed by the macroporous adsorption resin is elute using an alkaline solution to obtain a first eluent containing rebaudioside B; wherein the concentration of the alkaline solution is 0.5-5 wt%.

[0008] An acid solution was added to the first eluent to adjust its pH to 2.5–3.5, and the first eluent was then crystallized to obtain rebaudioside B.

[0009] Compared with existing technologies, the process for preparing rebaudioside B using stevia mother liquor in this invention involves passing the solution through a macroporous adsorption resin column. This allows the remaining steviol glycosides and rebaudioside B in the solution to be adsorbed by the macroporous adsorption resin. Since rebaudioside B is acidic or alkaline compared to other steviol glycosides, an alkaline solution is used as an eluent to elute the macroporous adsorption resin, removing only rebaudioside B in its ionic state, resulting in a first eluent containing rebaudioside B. The remaining steviol glycosides are still adsorbed by the macroporous adsorption resin. By adjusting the pH of the first eluent to 2.5–3.5, rebaudioside B can exist in its molecular state within the first eluent. After crystallizing the first eluent, rebaudioside B can be obtained. This invention solves the technical problems of complex processes, demanding process conditions, and high preparation costs associated with existing methods for preparing rebaudioside B.

[0010] Furthermore, in the process of preparing rebaudioside B using stevia mother liquor of the present invention, the alkaline solution is 0.5-5 wt% NaOH solution, 0.5-5 wt% KOH solution, or 0.5-5 wt% ammonia solution.

[0011] Furthermore, in the process of preparing rebaudioside B using stevia mother liquor of the present invention, the crystallization temperature is 40-55°C and the stirring rate is 25-100 rpm.

[0012] Furthermore, in the process for preparing rebaudine B using stevia mother liquor saccharide of the present invention, after obtaining rebaudine B, the process further includes:

[0013] Each 10g of the lebodiin B is placed in 40-150ml of ethanol solution and hot-washed at 40-60℃ for 1-3 hours. After drying, the purified lebodiin B product is obtained; wherein the concentration of the ethanol solution is 20-45 vt.

[0014] Furthermore, in the process for preparing rebaudioside B using stevia mother liquor of the present invention, after using an alkaline solution to elute the rebaudioside B adsorbed by the macroporous adsorption resin to obtain a first eluent containing rebaudioside B, before crystallizing the first eluent, the method further includes:

[0015] The macroporous adsorption resin is re-examined using a high-concentration alcohol of 70-85 vt% to obtain a second eluent containing steviol glycosides. The second eluent is then concentrated and crystallized to obtain crude steviol glycosides. The high-concentration alcohol is 70-85 vt% methanol or 70-85 vt% ethanol, and the concentration is performed at a temperature of 60-90°C and a stirring rate of 25-100 rpm.

[0016] Furthermore, in the process of preparing rebaudioside B using stevia mother liquor of the present invention, the solution of stevia mother liquor is obtained by mixing stevia mother liquor and pure water, and the mass ratio of stevia mother liquor to pure water in the solution is 1:(5-50).

[0017] Furthermore, in the process of preparing rebaudioside B using stevia mother liquor saccharide of the present invention, the total glycoside content of the stevia mother liquor saccharide is 40-65 wt%, and the rebaudioside B content is 3-12 wt%.

[0018] Furthermore, in the process of preparing rebaudioside B using stevia mother liquor sugar of the present invention, the feed amount of the solution after drying solids is 6-14 g / 100 ml of the volume of the macroporous adsorption resin.

[0019] Furthermore, in the process of preparing rebaudioside B using stevia mother liquor of the present invention, the acid solution is 5-25 wt% hydrochloric acid, citric acid, acetic acid or nitric acid.

[0020] Secondly, the present invention provides a rebaudioside B product, which is prepared according to the above-mentioned process for preparing rebaudioside B using stevia mother liquor saccharide. In the rebaudioside B product, the content of rebaudioside B is >95wt%, and the content of other stevia glycosides is <1wt%.

[0021] Compared with the prior art, the beneficial effects of the rebaudioside B product provided by the present invention are the same as the beneficial effects of the process method for preparing rebaudioside B using stevia mother liquor as described in the above technical solution, and will not be repeated here. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1This is a schematic flowchart of a process for preparing rebaudioside B using stevia mother liquor, as provided in an embodiment of the present invention. Detailed Implementation

[0024] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0025] Existing technologies for preparing rebaudioside B mainly use rebaudioside A, rebaudioside D, and rebaudioside J as reaction substrates, and obtain the product through high-temperature pyrolysis. The specific steps include: 1) Feeding: Add 2-15 L of purified water per 1 kg of reaction substrate and stir thoroughly; 2) High-temperature pyrolysis: Heat the dissolved material to 110-180℃ for pyrolysis and maintain the temperature for at least 1 hour until pyrolysis is complete; 3) Filtration: Keep the pyrolysis liquid stirred, cool it to 20-40℃ for crystallization, and filter; 4) Washing: Wash the filter cake obtained after filtration with purified water at 20-80℃ until the pH of the washing liquid is 5-7, then stop washing and dry to obtain crude rebaudioside B filter cake; 5) Purification: Dissolve the crude rebaudioside B filter cake and further purify it to obtain high-quality rebaudioside B. The above-mentioned technical solution has two drawbacks. On the one hand, the preparation process of rebaudine B is complex and the process conditions are harsh. On the other hand, the use of rebaudine A, rebaudine D, and rebaudine J as reactants results in high preparation costs for rebaudine B, which limits its large-scale production.

[0026] To address the aforementioned technical problems, in a first aspect, the present invention provides a process for preparing rebaudioside B using stevia mother liquor saccharide, comprising:

[0027] The solution of stevia mother liquor glycosides is passed through a macroporous adsorption resin column, so that rebaudioside B and other stevia glycosides in the solution are adsorbed by the macroporous adsorption resin.

[0028] The rebaudioside B adsorbed by the macroporous adsorption resin is elute using an alkaline solution to obtain a first eluent containing rebaudioside B; wherein the concentration of the alkaline solution is 0.5-5 wt%.

[0029] An acid solution was added to the first eluent to adjust its pH to 2.5–3.5, and the first eluent was then crystallized to obtain rebaudioside B.

[0030] Using the above technical solution, in the process of preparing rebaudioside B from stevia mother liquor of the present invention, by passing the solution through a macroporous adsorption resin column, the remaining steviol glycosides and rebaudioside B in the solution are adsorbed by the macroporous adsorption resin. Since rebaudioside B is acidic or alkaline, an alkaline solution is used as an eluent to elute the macroporous adsorption resin, eluting only the rebaudioside B in the macroporous adsorption resin in ionic form, resulting in the first eluent containing rebaudioside B, while the remaining steviol glycosides are still adsorbed by the macroporous adsorption resin. By adjusting the pH of the first eluent to 2.5–3.5, the rebaudioside B can exist in the first eluent in molecular form. After crystallizing the first eluent, rebaudioside B can be prepared.

[0031] It should be understood that, in order to improve the desorption efficiency of rebaudioside B adsorbed by the macroporous adsorption resin and to avoid the desorption of other steviol glycosides adsorbed by the macroporous adsorption resin, it is also necessary to control the concentration and type of the alkaline solution. For example, the alkaline solution is 0.5-5 wt% NaOH solution, 0.5-5 wt% KOH solution, or 0.5-5 wt% ammonia solution. As another example, the alkaline solution can be 3 wt% NaOH solution, 3 wt% KOH solution, and 3 wt% ammonia solution.

[0032] It should also be understood that in order to improve the crystallization efficiency of rebaudioside B in the first analysis and obtain a high-quality rebaudioside B product, it is also necessary to control the crystallization temperature and stirring rate. For example, the crystallization temperature is 40-55°C and the stirring rate is 25-100 rpm. In another example, the crystallization temperature can be 40°C, 45°C and 55°C, and the stirring rate can be 25 rpm, 30 rpm, 40 rpm, 50 rpm, 70 rpm and 100 rpm.

[0033] As one possible implementation, the process for preparing rebaudine B using stevia mother liquor saccharide of the present invention further includes, after obtaining rebaudine B:

[0034] Each 10g of the lebodiin B is placed in 40-150ml of ethanol solution and hot-washed at 40-60℃ for 1-3 hours. After drying, the purified lebodiin B product is obtained; wherein the concentration of the ethanol solution is 20-45 vt.

[0035] Using the above technical solution, the rebaudioside B is placed in an ethanol solution for hot washing. Impurities in the rebaudioside B will dissolve in the ethanol solution. After filtering and drying, high-quality rebaudioside B product can be obtained. To improve the purification efficiency of the rebaudioside B, the concentration of the ethanol solution is controlled at 20-45 vt%, the amount of ethanol solution used is 40-150 ml, and the hot washing temperature is 40-60°C. For example, the concentration of the ethanol solution can be 20 vt%, 30 vt%, and 45 vt, the amount of ethanol solution used can be 40 ml, 60 ml, 100 ml, and 150 ml, and the hot washing temperature can be 40°C, 50°C, and 60°C.

[0036] As one possible implementation, in the process of preparing rebaudine B using stevia mother liquor saccharide of the present invention, after using an alkaline solution to elute the rebaudine B adsorbed by the macroporous adsorption resin to obtain a first eluent containing rebaudine B, before crystallizing the first eluent, the method further includes:

[0037] The macroporous adsorption resin is re-examined using a high-concentration alcohol of 70-85 vt% to obtain a second eluent containing steviol glycosides. The second eluent is then concentrated and crystallized to obtain crude steviol glycosides. The high-concentration alcohol is 70-85 vt% methanol or 70-85 vt% ethanol, and the concentration is performed at a temperature of 60-90°C and a stirring rate of 25-100 rpm.

[0038] Using the above technical solution, after using an alkaline solution to elute the macroporous adsorption resin to obtain a first eluent containing rebaudioside B, the rebaudioside B adsorbed by the macroporous adsorption resin is eluted, while the remaining steviol glycosides are still adsorbed by the macroporous adsorption resin. High-concentration alcohol and steviol glycosides have strong miscibility; using high-concentration alcohol to elute the macroporous adsorption resin again can elute the steviol glycosides adsorbed by the macroporous adsorption resin, obtaining a second eluent containing steviol glycosides. The second eluent is then concentrated and crystallized to obtain crude steviol glycosides. It should be understood that, in order to improve the eluent glycoside elution efficiency, the concentration of the high-concentration alcohol is controlled to be 70-85 vt%. For example, the high concentration can be 70 vt% methanol, 70 vt% ethanol, 80 vt% methanol, and 85 vt% ethanol. It should also be understood that, in order to improve the efficiency of concentration of the second eluent, it is necessary to control the temperature and stirring rate during concentration. For example, the temperature during concentration can be 60°C, 70°C, 80°C and 90°C, and the stirring rate can be 25 rpm, 30 rpm, 45 rpm, 55 rpm, 70 rpm and 100 rpm.

[0039] As one possible implementation, in the process for preparing rebaudioside B using stevia mother liquor of the present invention, the solution of stevia mother liquor is obtained by mixing stevia mother liquor and pure water, and the mass ratio of stevia mother liquor to pure water in the solution is 1:(5-50). By adopting the above technical solution, by uniformly mixing stevia mother liquor and pure water in a certain proportion, the components in the stevia mother liquor are fully dissolved, resulting in a uniformly mixed solution with good flowability. When this solution passes through a macroporous adsorption resin column, it can prevent clogging of the macroporous adsorption resin and also allow the macroporous adsorption resin to uniformly adsorb rebaudioside B, thereby improving the adsorption efficiency of the macroporous adsorption resin for rebaudioside B. It should be understood that, in order to further improve the adsorption efficiency of the macroporous adsorption resin for rebaudioside B, the present invention controls the mass ratio of stevia mother liquor to pure water to be 1:(5-50). For example, the mass ratio of stevia mother liquor to pure water can be 1:5, 1:15, 1:25, and 1:50.

[0040] It should be understood that, in order to improve the yield of rebaudioside B, the embodiments of the present invention also need to control the content of total glycosides and rebaudioside B in the stevia mother liquor syrup. For example, the total glycoside content in the stevia mother liquor syrup is 40-65 wt%, and the rebaudioside B content is 3-12 wt%. In another example, the total glycoside content in the stevia mother liquor syrup can be 40 wt%, 50 wt%, and 60 wt%, and the rebaudioside B content can be 5 wt%, 10 wt%, and 12 wt%, with the remainder being impurities.

[0041] It should also be understood that, in order for the macroporous adsorption resin to achieve saturated adsorption of rebaudioside B and the remaining steviol glycosides in the solution, the feed rate of the solution must be controlled. In this invention, the feed rate of the solution (dry solids content) is 6 to 14 g / 100 ml of the volume of the macroporous adsorption resin. For example, the feed rate of the solution (dry solids content) can be 7 g / 100 ml or 11 g / 100 ml of the volume of the macroporous adsorption resin.

[0042] It should also be understood that in the process of adjusting the pH of the first eluent to 2.5-3.5 by adding an acid solution to the first eluent, the type and concentration of the acid solution also need to be controlled. For example, the acid solution is 5-25 wt% hydrochloric acid, citric acid, acetic acid or nitric acid. In another example, the acid solution is 5 wt% hydrochloric acid, 5 wt% nitric acid, 20 wt% acetic acid and 25 wt% citric acid.

[0043] Secondly, the present invention provides a rebaudioside B product, which is prepared according to the above-mentioned process for preparing rebaudioside B using stevia mother liquor saccharide. In the rebaudioside B product, the content of rebaudioside B is >95wt%, and the content of other stevia glycosides is <1wt%.

[0044] Compared with the prior art, the beneficial effects of the rebaudioside B product provided by the present invention are the same as the beneficial effects of the process method for preparing rebaudioside B using stevia mother liquor as described in the above technical solution, and will not be repeated here.

[0045] To better understand the present invention, the following specific embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0046] Unless otherwise specified, all raw materials used in the following examples are commercially available.

[0047] Example 1

[0048] This embodiment provides a process for preparing rebaudioside B using stevia mother liquor saccharide, including the following steps:

[0049] S100, obtain 200g of stevia mother liquor syrup, and mix the stevia mother liquor syrup syrup with pure water at a mass ratio of 1:25 to obtain a solution of stevia mother liquor syrup syrup; wherein, the total glycoside content of the stevia mother liquor syrup syrup syrup is 41.5wt%, the content of rebaudioside B is 5.2wt%, and the remainder is impurities;

[0050] S200, the solution is passed through a macroporous adsorption resin column, so that rebaudioside B and the remaining steviol glycosides in the solution are adsorbed by the macroporous adsorption resin; wherein, the feed amount of the solution with dry solids is 7g / 100ml of the volume of the macroporous adsorption resin, the amount of the macroporous adsorption resin is 2800ml, and the flow rate of the solution through the column is 2BV / h.

[0051] S300, using a 3wt% NaOH solution to elute the rebaudioside B adsorbed by the macroporous adsorption resin, to obtain an eluent containing rebaudioside B; wherein, the amount of NaOH solution used is 5600 ml, and the flow rate of the NaOH solution through the column is 0.5 BV / h;

[0052] S400, while stirring, 5 wt% hydrochloric acid is added to the eluent to adjust the pH value of the eluent to 3, and the eluent is crystallized at a temperature of 50°C and a stirring rate of 50 rpm to precipitate rebaudioside B in the eluent, and then filtered through a Buchner funnel to obtain crude rebaudioside B.

[0053] In this embodiment, a total of 10.5g of crude rebaudioside B was prepared, wherein the crude rebaudioside B contained 88.5wt% rebaudioside B and the remaining steviol glycosides contained 1.4wt%.

[0054] Example 2

[0055] This embodiment provides a process for preparing rebaudioside B using stevia mother liquor saccharide, including the following steps:

[0056] S100, obtain 200g of stevia mother liquor syrup, and mix the stevia mother liquor syrup with pure water at a mass ratio of 1:5 to obtain a solution of stevia mother liquor syrup; wherein, the total glycoside content of the stevia mother liquor syrup is 51.8wt%, the content of rebaudioside B is 7.9wt%, and the remainder is impurities;

[0057] S200, the solution is passed through a macroporous adsorption resin column, so that rebaudioside B and the remaining steviol glycosides in the solution are adsorbed by the macroporous adsorption resin; wherein, the feed amount of the solution with dry solids is 11g / 100ml of the volume of the macroporous adsorption resin, the amount of macroporous adsorption resin used is 1800ml, and the flow rate of the solution through the column is 2BV / h.

[0058] S300, using 0.5wt% ammonia water to elute the rebaudioside B adsorbed by the macroporous adsorption resin, to obtain a first eluent containing rebaudioside B; wherein, the amount of ammonia water used is 7200ml, and the flow rate of the ammonia water through the column is 2BV / h;

[0059] S400, while stirring, 5 wt% nitric acid is added to the first eluent to adjust the pH value of the eluent to 2.5, and the eluent is crystallized at a temperature of 40°C and a stirring rate of 100 rpm to crystallize the rebaudioside B in the first eluent, and then filtered through a Buchner funnel to obtain crude rebaudioside B.

[0060] S500, 10g of the crude rebaudioside B is placed in 100ml of ethanol solution and hot-washed at 50℃ for 2h, then dried at 60℃ to obtain high-quality rebaudioside B product; wherein the concentration of the ethanol solution is 30vt%.

[0061] S600, the macroporous adsorption resin is eluted again using 70 vt% methanol to obtain a second eluent containing steviol glycosides; the second eluent is concentrated and crystallized by stirring at 60°C and 50 rpm, and then filtered through a Buchner funnel to obtain crude steviol glycosides. The crude steviol glycosides can be purified to obtain high-quality steviol glycosides.

[0062] In this embodiment, a total of 13.7g of rebaudioside B product was prepared, wherein the rebaudioside B content was 96.7wt% and the content of the remaining steviol glycosides was 0.6wt%.

[0063] Example 3

[0064] This embodiment provides a process for preparing rebaudioside B using stevia mother liquor saccharide, including the following steps:

[0065] S100, obtain 200g of stevia mother liquor syrup, and mix the stevia mother liquor syrup syrup with pure water at a mass ratio of 1:50 to obtain a solution of stevia mother liquor syrup syrup; wherein, the total glycoside content of the stevia mother liquor syrup syrup syrup is 60.5wt%, the content of rebaudioside B is 9.6wt%, and the remainder is impurities;

[0066] S200, the solution is passed through a macroporous adsorption resin column, so that rebaudioside B and the remaining steviol glycosides in the solution are adsorbed by the macroporous adsorption resin; wherein, the feed amount of the solution with dry solids is 14g / 100ml of the volume of the macroporous adsorption resin, the amount of macroporous adsorption resin used is 1400ml, and the flow rate of the solution through the column is 2BV / h.

[0067] S300, using a 5wt% KOH solution to elute the rebaudioside B adsorbed by the macroporous adsorption resin, to obtain a first eluent containing rebaudioside B; wherein, the volume of the KOH solution used is 3000 ml, and the flow rate of the KOH solution through the column is 2 BV / h;

[0068] S400, while stirring, 20wt% acetic acid is added to the first eluent to adjust the pH value of the eluent to 3.5, and the eluent is crystallized at a temperature of 55℃ and a stirring rate of 25rpm to crystallize the rebaudioside B in the first eluent, and then filtered through a Buchner funnel to obtain crude rebaudioside B.

[0069] S500, 10g of the crude rebaudioside B is placed in 40ml of ethanol solution and hot-washed at 60℃ for 1h, filtered and dried at 70℃ to obtain high-quality rebaudioside B product; wherein the concentration of the ethanol solution is 20vt%.

[0070] S600, the macroporous adsorption resin is eluted again using 85 wt% ethanol to obtain a second eluent containing steviol glycosides; the second eluent is concentrated and crystallized by stirring at 70°C and 100 rpm, and then filtered through a Buchner funnel to obtain crude steviol glycosides; the crude steviol glycosides can be purified to obtain high-quality steviol glycosides.

[0071] In this embodiment, a total of 17.4g of rebaudioside B product was prepared. The rebaudioside B product contained 97.1wt% rebaudioside B and 0.5wt% of the remaining steviol glycosides.

[0072] Example 4

[0073] S100, obtain 200g of stevia mother liquor syrup, and mix the stevia mother liquor syrup syrup with pure water at a mass ratio of 1:30 to obtain a solution of stevia mother liquor syrup syrup; wherein, the total glycoside content of the stevia mother liquor syrup syrup syrup is 64.1wt%, the content of rebaudioside B is 11.7wt%, and the remainder is impurities;

[0074] S200, the solution is passed through a macroporous adsorption resin column, so that both rebaudioside B and steviol glycoside in the solution are adsorbed by the macroporous adsorption resin; wherein, the feed amount of the solution with dry solids is 10g / 100ml of the volume of the macroporous adsorption resin, the amount of macroporous adsorption resin used is 2000ml, and the flow rate of the solution through the column is 2BV / h.

[0075] S300, using a 5wt% NaOH solution to elute the rebaudioside B adsorbed by the macroporous adsorption resin, to obtain a first eluent containing rebaudioside B; wherein, the amount of NaOH solution used is 5000ml, and the flow rate of the NaOH solution through the column is 2BV / h;

[0076] S400, while stirring, 25wt% citric acid is added to the first eluent to adjust the pH of the eluent to 3, and the eluent is crystallized at a temperature of 60℃ and a stirring rate of 45rpm to crystallize the rebaudioside B in the first eluent, and then filtered through a Buchner funnel to obtain crude rebaudioside B.

[0077] S500, 10g of the crude rebaudioside B is placed in 150ml of ethanol solution and hot-washed at 40℃ for 3h, filtered and dried at 80℃ to obtain high-quality rebaudioside B product; wherein the concentration of the ethanol solution is 45vt%.

[0078] S600, the macroporous adsorption resin is eluted again using 80 vt% methanol to obtain a second eluent containing steviol glycosides; the second eluent is concentrated and crystallized by stirring at 90°C and 55 rpm, and then filtered through a Buchner funnel to obtain crude steviol glycosides. The crude steviol glycosides can be purified to obtain high-quality steviol glycosides.

[0079] In this embodiment, a total of 20.1g of rebaudioside B product was prepared, wherein the rebaudioside B content was 97.9wt% and the content of the remaining steviol glycosides was 0.2wt%.

[0080] Comparative Example

[0081] The process for preparing rebaudioside B using stevia mother liquor provided in this comparative example is basically the same as that in Example 1, except that in step S300, 5600 ml of 70 wt% methanol is used to desorb the macroporous adsorption resin to obtain the first desorbent.

[0082] After crystallization, 0.5 g of crude rebaudioside B was obtained from the first eluent of this comparative example. The crude rebaudioside B contained 71.6 wt% rebaudioside B and 8.9 wt% other steviosides.

[0083] As can be seen, in this comparative example, after using methanol as the eluent to elute the macroporous adsorption resin, the content of rebaudioside B in the crude rebaudioside B product was lower than that in Example 1, while the content of the other steviol glycosides was much higher than the 1.4 wt% in Example 1. This is because methanol simultaneously elutes the rebaudioside B and the other steviol glycosides adsorbed by the macroporous adsorption resin, resulting in a lower rebaudioside B content in the crude rebaudioside B product compared to Example 1. Therefore, by controlling the eluent to be an alkaline solution to elute the rebaudioside B adsorbed by the macroporous adsorption resin, this invention can effectively improve the purity of the rebaudioside B product and obtain a high-quality rebaudioside B product.

[0084] Through the above embodiments, comparative examples, and test data of rebaudioside B products, high-quality rebaudioside B products can be prepared under the conditions of the embodiments of the present invention, solving the technical problems of complex preparation process, harsh process conditions, and high preparation cost in the preparation of rebaudioside B in the prior art.

[0085] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A process for preparing rebaudioside B using stevia mother liquor saccharide, characterized in that, include: The solution of stevia mother liquor glycosides is passed through a macroporous adsorption resin column, so that rebaudioside B and other stevia glycosides in the solution are adsorbed by the macroporous adsorption resin. The rebaudioside B adsorbed by the macroporous adsorption resin is elute using an alkaline solution to obtain a first eluent containing rebaudioside B; wherein the alkaline solution is 0.5-5 wt% NaOH solution, 0.5-5 wt% KOH solution, or 0.5-5 wt% ammonia solution; An acid solution was added to the first eluent to adjust its pH to 2.5-3.5, and the first eluent was crystallized to obtain rebaudioside B.

2. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 1, characterized in that, The crystallization temperature is 40~55℃ and the stirring speed is 25~100rpm.

3. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 1, characterized in that, After obtaining lebodiin B, the process further includes: Each 10g of the rebaudioside B is placed in 40-150ml of ethanol solution and hot-washed at 40-60℃ for 1-3h. After drying, the purified rebaudioside B product is obtained; wherein the concentration of the ethanol solution is 20-45vt.

4. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 1, characterized in that, After using an alkaline solution to elute the rebaudioside B adsorbed by the macroporous adsorption resin to obtain a first eluent containing rebaudioside B, the method further includes, before crystallizing the first eluent: The macroporous adsorption resin is re-examined using a high-concentration alcohol of 70-85 vt% to obtain a second eluent containing steviol glycosides. The second eluent is then concentrated and crystallized to obtain crude steviol glycosides. The high-concentration alcohol is 70-85 vt% methanol or 70-85 vt% ethanol, and the concentration temperature is 60-90°C and the stirring rate is 25-100 rpm.

5. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 1, characterized in that, The solution of stevia mother liquor is obtained by mixing stevia mother liquor and pure water, and the mass ratio of stevia mother liquor to pure water in the solution is 1:(5~50).

6. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 5, characterized in that, The total glycoside content of the stevia mother liquor is 40-65 wt%, and the content of rebaudioside B is 3-12 wt%.

7. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 1, characterized in that, The feed amount of the solution, calculated as dry solids, is 6-14 g / 100 ml of the volume of the macroporous adsorption resin.

8. The process for preparing rebaudioside B using stevia mother liquor saccharide according to claim 1, characterized in that, The acid solution is 5-25 wt% hydrochloric acid, acetic acid, citric acid or nitric acid.

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