Method for preparing rebaudioside B by using stevia mother liquor sugar and rebaudioside B product

Abstract

The invention discloses a method for preparing rebaudioside B by using stevia mother liquor sugar and a rebaudioside B product, relates to the technical field of rebaudioside B preparation, and aims to solve the technical problems of complex preparation process, harsh reaction conditions and poor quality of the prepared rebaudioside B when the rebaudioside B is prepared in the prior art. The method for preparing rebaudioside B by using stevia mother liquor sugar comprises the following steps: enabling a dissolving solution of the stevia mother liquor sugar to pass through an anion exchange resin column; resolving the anion exchange resin by using an alkali alcohol solution to obtain a resolving solution containing rebaudioside B; adjusting the pH value of the desorption solution to 3-4.5 by using an acid solution, stirring the desorption solution until the rebaudioside B is crystallized and separated out, filtering, and drying a filter cake to obtain a rebaudioside B product. The method for preparing rebaudioside B by using stevia mother liquor sugar provided by the invention is used for preparing a high-quality rebaudioside B product.

Description

Technical Field

[0001] The invention relates to the technical field of rebaudioside B preparation, and in particular to a method for preparing rebaudioside B by utilizing stevia mother liquor sugar and a rebaudioside B product. Background Art

[0002] Stevioside is a new type of natural sweetener extracted from the leaves of Stevia rebaudiana, a perennial herbaceous plant of the Asteraceae family. It has the characteristics of high sweetness and low calorie, and is an ideal sweetener that can replace sucrose. Rebaudioside B is one of the sweet ingredients in steviol glycosides. Studies have found that in addition to its strong sweetness, rebaudioside B also has the physiological effect of lowering blood lipids, and is a new generation of functional sweeteners. However, the content of rebaudioside B in steviol glycosides is relatively small, and the existing process of producing rebaudioside B using purified steviol glycosides is very costly and difficult to mass produce and promote for use.

[0003] The prior art provides a method for preparing a rebaudioside B product, which is to prepare laminaribiose and rebaudioside B by alkaline hydrolysis of rebaudioside I, and the specific steps include: keeping the rebaudioside I aqueous solution at a constant temperature of 80°C to 100°C for 0.5h, adding alkali according to the catalyst to substrate molar ratio of 1:10 to 20:1, reacting at 80°C to 100°C for 2 to 10h until rebaudioside I is completely hydrolyzed, and then neutralizing with 0.1mol / L acid, the product laminaribiose remains in the solution, and another product rebaudioside B is precipitated from the solution, and the filter cake is dried after filtration to obtain the rebaudioside B product. In the above technical scheme, the preparation process of the rebaudioside B product is complicated and the reaction conditions are harsh, and after the acid neutralization is completed, laminaribiose and rebaudioside B coexist in the solution, and the quality of the prepared rebaudioside B product is poor, and even if alcohol is used for recrystallization, the impurities cannot be completely removed. Therefore, a new preparation method of rebaudioside B is urgently needed to solve the above technical problems. Summary of the invention

[0004] In order to solve the technical problems of the complicated preparation process, harsh reaction conditions and poor quality of the prepared rebaudioside B in the prior art, the present invention provides a method for preparing rebaudioside B using stevia mother liquor sugar and a rebaudioside B product. In view of this, the present invention is implemented through the following technical solutions.

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

[0006] Passing the dissolved solution of stevia mother liquor sugar through an anion exchange resin column, so that rebaudioside B in the dissolved solution is adsorbed by the anion exchange resin, and the remaining stevioside flows out as an effluent;

[0007] The anion exchange resin is resolved by using an alkali alcohol solution to obtain a resolved solution containing rebaudioside B;

[0008] The pH value of the analytical solution is adjusted to 3-4.5 with an acid solution, and the analytical solution is stirred until rebaudioside B crystals are precipitated. After filtering, the filter cake is dried to obtain a rebaudioside B product.

[0009] Compared with the prior art, in the method for preparing rebaudioside B using stevia mother liquor sugar of the present invention, during the process of passing the dissolved solution of stevia mother liquor sugar through an anion exchange resin column, since rebaudioside B in stevia mother liquor sugar contains a carboxyl group at the C19 position, the charge of the sulfonic acid group or hydroxyl group on the surface of the anion exchange resin first interacts with the charge of rebaudioside B containing the carboxyl group in the dissolved solution, and rebaudioside B forms a stable polymer on the surface of the anion exchange resin, so that the rebaudioside B is adsorbed by the anion exchange resin. Since the anion exchange resin has a strong adsorption force on the rebaudioside B, the present invention uses an alkali alcohol solution with stronger resolving ability as a resolving agent to resolve the rebaudioside B adsorbed by the anion exchange resin to obtain a resolved solution containing rebaudioside B. The present invention can suppress the ionization of the carboxyl group of rebaudioside B in the analytical solution by adjusting the pH value of the analytical solution to 3-4.5, so that rebaudioside B exists in the analytical solution in a molecular state, and after the rebaudioside B in the analytical solution is crystallized and separated, the rebaudioside B product can be obtained. The above technical solution of the present invention solves the technical problems of the complicated preparation process, harsh reaction conditions and poor quality of the prepared rebaudioside B in the prior art.

[0010] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, the alkali-alcohol solution is a mixed solution of 30-50wt% alkali solution and 60-85vt% alcohol solution; wherein the volume ratio of the alkali solution to the alcohol solution in the alkali-alcohol solution is 1:(8-80).

[0011] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, the alkaline solution comprises 30-50wt% NaOH solution, 30-50wt% KOH solution or 30-50wt% ammonia water; and / or,

[0012] The alcohol solution includes 60-85vt% methanol solution, 60-85vt% ethanol solution or 60-85vt% propanol solution.

[0013] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, the injection amount of the dissolved liquid as dry solid content is 60 to 120 g / 100 ml of the volume of the anion exchange resin.

[0014] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, after obtaining the analytical solution containing rebaudioside B and before adjusting the pH value of the analytical solution to 3 to 4.5 with an acid solution, the method further comprises:

[0015] Under the conditions of a temperature of 50 to 90° C. and a stirring rate of 25 to 100 rpm, the analytical solution is concentrated to an alcohol concentration of 10 to 40 wt % and a solid content of 5 to 20 wt %.

[0016] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, the dissolving liquid of stevia mother liquor sugar is a mixed solution of stevia mother liquor sugar and pure water, and the mass ratio of stevia mother liquor sugar to pure water in the mixed solution is 1:(4-50); and / or,

[0017] The total glycoside content in the stevia mother liquor sugar is 40-60wt%, and the remainder is impurities; wherein the content of rebaudioside B in the total glycosides is 3-12wt%.

[0018] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, in the process of adjusting the pH value of the analytical solution to 3-4.5 with an acid solution, the concentration of the acid solution is 5-40wt%; and / or,

[0019] The acid solution includes 5-40 wt % of hydrochloric acid, 5-40 wt % of nitric acid or 5-40 wt % of acetic acid.

[0020] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, during the process of concentrating the analytical solution until rebaudioside B crystallizes out, the temperature during the crystallization is 30-60° C. and the stirring rate is 25-100 rpm.

[0021] Furthermore, in the method for preparing rebaudioside B using stevia mother liquor sugar provided by the present invention, the temperature when drying the filter cake is 65-95°C.

[0022] In a second aspect, the present invention provides a rebaudioside B product, which is prepared according to the above-mentioned method for preparing rebaudioside B using stevia mother liquor sugar, wherein the rebaudioside B content in the rebaudioside B product is greater than 96wt%, the content of other steviosides is less than 2wt%, the remainder is flavonoid compounds, and the overall recovery rate of rebaudioside B is greater than 85%.

[0023] 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 method for preparing rebaudioside B using stevia mother liquor sugar as described in the above technical scheme, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 This is a liquid chromatogram of rebaudioside B prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] The prior art provides a method for preparing a rebaudioside B product, which is to prepare laminaribiose and rebaudioside B by alkaline hydrolysis of rebaudioside I, and the specific steps include: keeping the rebaudioside I aqueous solution at a constant temperature of 80°C to 100°C for 0.5h, adding alkali according to the catalyst to substrate molar ratio of 1:10 to 20:1, reacting at 80°C to 100°C for 2 to 10h until rebaudioside I is completely hydrolyzed, and then neutralizing with 0.1mol / L acid, the product laminaribiose remains in the solution, and another product rebaudioside B is precipitated from the solution, and the filter cake is dried after filtration to obtain the rebaudioside B product. In the above technical scheme, the preparation process of the rebaudioside B product is complicated, the reaction conditions are harsh, and after the acid neutralization is completed, laminaribiose and rebaudioside B coexist in the solution, and the quality of the prepared rebaudioside B product is poor, and even if the alcohol is recrystallized, the impurities cannot be completely removed.

[0028] In order to solve the above technical problems, in a first aspect, the present invention provides a method for preparing rebaudioside B using stevia mother liquor sugar, comprising:

[0029] Passing the dissolved solution of stevia mother liquor sugar through an anion exchange resin column, so that rebaudioside B in the dissolved solution is adsorbed by the anion exchange resin, and the remaining stevioside flows out as an effluent;

[0030] The anion exchange resin is resolved by using an alkali alcohol solution to obtain a resolved solution containing rebaudioside B;

[0031] The pH value of the analytical solution is adjusted to 3-4.5 with an acid solution, and the analytical solution is stirred until rebaudioside B crystals are precipitated. After filtering, the filter cake is dried to obtain a rebaudioside B product.

[0032] By adopting the above technical scheme, in the method for preparing rebaudioside B using stevia mother liquor sugar of the present invention, during the process of passing the dissolved solution of stevia mother liquor sugar through an anion exchange resin column, since the rebaudioside B contained in the stevia mother liquor sugar contains a carboxyl group at the C19 position, the charge of the sulfonic acid group or hydroxyl group on the surface of the anion exchange resin first interacts with the charge of the rebaudioside B containing the carboxyl group in the dissolved solution, and rebaudioside B forms a stable polymer on the surface of the anion exchange resin, so that the rebaudioside B is adsorbed by the anion exchange resin. Specifically, the anion exchange resin includes a strong alkaline anion exchange resin, a polystyrene anion exchange resin or a polyacrylamide anion exchange resin. Since the anion exchange resin has a strong adsorption force on the rebaudioside B, the present invention uses an alkali alcohol solution with stronger resolving ability as a resolving agent to resolve the rebaudioside B adsorbed by the anion exchange resin to obtain a resolved solution containing rebaudioside B. The present invention can suppress the ionization of the carboxyl group of rebaudioside B in the analytical solution by adjusting the pH value of the analytical solution to 3-4.5, so that rebaudioside B exists in the analytical solution in a molecular state, and after the rebaudioside B in the analytical solution is crystallized and separated, the rebaudioside B product can be obtained.

[0033] It should be understood that in the method of preparing rebaudioside B using stevia mother liquor sugar of the present invention, in order to improve the resolution efficiency of the alkaline-alcohol solution on rebaudioside B adsorbed by the anion exchange resin and improve the recovery rate of rebaudioside B, the present invention also needs to separately control the concentrations of the alkaline solution and the alcohol solution in the alkaline-alcohol solution, as well as the mixing ratio of the alkaline solution and the alcohol solution in the alkaline-alcohol solution. For example, the alkaline-alcohol solution is a mixed solution of 30-50wt% of alkaline solution and 60-85vt% of alcohol solution, and the volume ratio of the alkaline solution to the alcohol solution in the alkaline-alcohol solution is 1:(8-80). Furthermore, when the volume ratio of the alkali solution to the alcohol solution in the alkali-alcohol solution is 1:(30-40), the best analysis effect can be achieved. While rebaudioside B is completely analyzed, the structure of rebaudioside B can be kept as intact as possible. As another example, the alkali-alcohol solution can be a mixed solution of 30wt% alkali solution and 60vt% alcohol solution, a mixed solution of 40wt% alkali solution and 70vt% alcohol solution, or a mixed solution of 50wt% alkali solution and 85vt% alcohol solution. The volume ratio of the alkali solution to the alcohol solution in the alkali-alcohol solution can be 1:8, 1:25, 1:50 or 1:80.

[0034] It should also be understood that in the method of preparing rebaudioside B using stevia mother liquor sugar of the present invention, in order to improve the resolution efficiency of the alkaline alcohol solution on rebaudioside B adsorbed by the anion exchange resin, it is also necessary to control the types of the alkaline solution and the alcohol solution. For example, the alkaline solution includes 30-50wt% NaOH solution, 30-50wt% KOH solution or 30-50wt% ammonia water; the alcohol solution includes 60-85vt% methanol solution, 60-85vt% ethanol solution or 60-85vt% propanol solution; for another example, the alkaline solution can be 30wt% NaOH solution, 40wt% KOH solution or 50wt% ammonia water, and the alcohol solution can be 60vt% methanol solution, 70vt% propanol solution or 85vt% ethanol solution.

[0035] It should also be understood that in the method of preparing rebaudioside B using stevia mother liquor sugar of the present invention, in order to allow the anion exchange resin to achieve saturated adsorption of rebaudioside B in the dissolved solution, the feed amount of the dissolved solution must be controlled. For example, the feed amount of the dissolved solution as a dry solid content is 60 to 120 g / 100 ml of the volume of the anion exchange resin; for another example, the feed amount of the dissolved solution as a dry solid content can be 60 g / 100 ml, 80 g / 100 ml or 120 g / 100 ml of the volume of the anion exchange resin.

[0036] As a possible embodiment, in the method for preparing rebaudioside B using stevia mother liquor sugar of the present invention, after obtaining the analytical solution containing rebaudioside B and before adjusting the pH value of the analytical solution to 3-4.5 with an acid solution, it also includes: concentrating the analytical solution to an alcohol concentration of 10-40vt% and a solid content of 5-20wt% under the conditions of a temperature of 50-90°C and a stirring rate of 25-100rpm. Using the above technical solution, the present invention controls the alcohol content of the analytical solution to 10-40vt% and the solid content to 5-20wt%, so that the rebaudioside B of the analytical solution is in a saturated state, and the crystallization efficiency of rebaudioside B can be improved in the crystallization stage. For example, the temperature can be 50°C, 60°C, 80°C or 90°C, and the stirring rate can be 25rpm, 45rpm, 55rpm, 70rpm or 100rpm.

[0037] As a possible embodiment, in the method for preparing rebaudioside B using stevia mother liquor sugar of the present invention, the dissolving liquid of stevia mother liquor sugar is a mixed solution of stevia mother liquor sugar and pure water, and the mass ratio of stevia mother liquor sugar to pure water in the mixed solution is 1: (4-50); and / or,

[0038] The total glycoside content in the stevia mother liquor sugar is 40-60wt%, and the remainder is impurities; wherein the content of rebaudioside B in the total glycosides is 3-12wt%.

[0039] By adopting the above technical scheme, the present invention can disperse the rebaudioside B and other components in the stevia mother liquid sugar in the pure water by mixing stevia mother liquid sugar and pure water, thereby obtaining a uniformly mixed dissolved solution, which is beneficial to the uniform adsorption of rebaudioside B by the anion exchange resin when the dissolved solution passes through the column. Controlling the mass ratio of stevia mother liquid sugar to pure water in the mixed solution can indirectly control the fluidity of the dissolved solution and the content of each component in the dissolved solution. Furthermore, in order to improve the yield of rebaudioside B, the present invention controls the total glycoside content in stevia mother liquor sugar to be 40-60wt%, and the rebaudioside B content in the total glycosides to be 3-12wt%. In the process of passing the dissolved solution through an anion exchange resin column, the anion exchange resin specifically and saturatedly adsorbs rebaudioside B, so that the adsorption sites on the anion exchange resin are occupied by the rebaudioside B, and the remaining steviol glycosides and impurities flow out with the effluent; for example, the total glycoside content in the stevia mother liquor sugar can be 40wt%, 50wt% or 60wt%, and the rebaudioside B content in the total glycosides can be 3wt%, 5wt%, 7wt% or 12wt%.

[0040] It should be understood that in the method for preparing rebaudioside B using stevia mother liquor sugar of the present invention, in the process of adjusting the pH value of the analytical solution to 3-4.5 with an acid solution, in order to improve the efficiency of adjusting the pH value of the analytical solution and for safety considerations, the concentration and type of the acid solution need to be controlled. For example, the concentration of the acid solution is 5-40wt%; further, the acid solution includes 5-40wt% hydrochloric acid, 5-40wt% nitric acid or 5-40wt% acetic acid; for another example, the acid solution can be 5wt% hydrochloric acid, 25wt% hydrochloric acid, 30wt% nitric acid, 40wt% nitric acid or 20wt% acetic acid.

[0041] It should also be understood that in the method of preparing rebaudioside B using stevia mother liquor sugar of the present invention, in the process of concentrating the analytical solution to crystallize rebaudioside B, in order to improve the crystallization efficiency of rebaudioside B, it is also necessary to control the temperature and stirring rate during crystallization. For example, the temperature during crystallization is 30-60°C and the stirring rate is 25-100rpm; for another example, the temperature during crystallization can be 30°C, 40°C or 60°C, and the stirring rate can be 25rpm, 40rpm, 60rpm or 100rpm.

[0042] It should also be understood that in the method for preparing rebaudioside B using stevia mother liquor sugar of the present invention, in order to reduce the drying time when the filter cake is dried and to avoid damage to the structure of rebaudioside B during drying, the drying temperature must be controlled. For example, the drying temperature is 65 to 95°C. For another example, the drying temperature can be 65°C, 70°C, 80°C or 95°C.

[0043] In a second aspect, the present invention provides a rebaudioside B product, which is prepared according to the above-mentioned method for preparing rebaudioside B using stevia mother liquor sugar, wherein the rebaudioside B content in the rebaudioside B product is greater than 96wt%, the content of other steviosides is less than 2wt%, the remainder is flavonoid compounds, and the overall recovery rate of rebaudioside B is greater than 85%.

[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 method for preparing rebaudioside B using stevia mother liquor sugar as described in the above technical scheme. At the same time, by controlling the rebaudioside B content in the rebaudioside B product to be greater than 96wt%, the content of other steviosides to be less than 2wt%, and the overall recovery rate of rebaudioside B to be greater than 85%, the present invention can prepare a high-quality rebaudioside B product and control the overall recovery rate of rebaudioside B at a relatively high level.

[0045] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific examples, but the content of the present invention is not limited to the following examples. The raw materials used in the following examples are all commercially available raw materials unless otherwise specified.

[0046] Example 1

[0047] This embodiment provides a method for preparing rebaudioside B using stevia mother liquor sugar, comprising the following steps:

[0048] S100, dissolving 500 g of stevia mother liquid sugar in pure water to obtain a solution; wherein the mass ratio of the stevia mother liquid sugar to pure water is 1:4, and the total glycoside content of the stevia mother liquid sugar is 40.9 wt%, and the rebaudioside B content is 3.1 wt%;

[0049] S200, passing the dissolved solution in step S100 through a strong basic anion exchange resin column, wherein the rebaudioside B in the dissolved solution is adsorbed by the strong basic anion exchange resin, and the remaining stevioside flows out as an effluent; wherein the dosage of the strong basic anion exchange resin is 420 ml, the column flow rate of the dissolved solution in the strong basic anion exchange resin is 3 BV / h, and the injection amount of the dissolved solution as dry solid content is 120 g / 100 ml of the volume of the strong basic anion exchange resin;

[0050] S300, using 1000 ml of an alkali-alcohol solution as an analytical agent to analyze the rebaudioside B adsorbed by the strong basic anion exchange resin to obtain an analytical solution containing rebaudioside B; wherein the alkali-alcohol solution is a mixed solution of 30 wt% NaOH solution and 60 vt% methanol solution, and the volume ratio of the NaOH solution to the methanol solution in the alkali-alcohol solution is 1:8, and the flow rate of the alkali-alcohol solution through the column in the strong basic anion exchange resin is 2 BV / h;

[0051] S400, adding 40wt% hydrochloric acid to the analytical solution in step S300 to adjust the pH value of the analytical solution to 3, and stirring the analytical solution at a temperature of 30°C and a stirring rate of 100rpm until rebaudioside B crystals are precipitated, filtering the analytical solution using a Buchner funnel to obtain a rebaudioside B filter cake, and drying the rebaudioside B filter cake at 65°C to obtain a high-quality rebaudioside B product.

[0052] In this embodiment, a total of 13.8 g of rebaudioside B product was prepared, in which the content of rebaudioside B in the rebaudioside B product was 96.5 wt %, the content of the remaining steviosides was 1.4 wt %, and the overall recovery rate of rebaudioside B was 85.9%.

[0053] Example 2

[0054] This embodiment provides a method for preparing rebaudioside B using stevia mother liquor sugar, comprising the following steps:

[0055] S100, dissolving 500 g of stevia mother liquid sugar in pure water to obtain a solution; wherein the mass ratio of the stevia mother liquid sugar to pure water is 1:50, and the total glycoside content of the stevia mother liquid sugar is 59.4 wt%, and the rebaudioside B content is 12.0 wt%;

[0056] S200, passing the dissolved solution in step S100 through a polystyrene anion exchange resin column, wherein the rebaudioside B in the dissolved solution is adsorbed by the polystyrene anion exchange resin, and the remaining stevioside flows out as an effluent; wherein the amount of the polystyrene anion exchange resin is 830 ml, the flow rate of the dissolved solution through the polystyrene anion exchange resin column is 3 BV / h, and the injection amount of the dissolved solution as a dry solid content is 60 g / 100 ml of the volume of the polystyrene anion exchange resin;

[0057] S300, using 2000 ml of an alkali-alcohol solution as an analytical agent to analyze the rebaudioside B adsorbed by the polystyrene anion exchange resin to obtain an analytical solution containing rebaudioside B; wherein the alkali-alcohol solution is a mixed solution of 50wt% KOH solution and 85vt% ethanol solution, and the volume ratio of the KOH solution to the ethanol solution in the alkali-alcohol solution is 1:80, and the flow rate of the alkali-alcohol solution through the polystyrene anion exchange resin is 2BV / h;

[0058] S400, at a temperature of 50° C. and a stirring rate of 25 rpm, concentrating the analytical solution to an alcohol concentration of 10 wt% and a solid content of 5 wt%;

[0059] S500, adding 5wt% nitric acid to the concentrated analytical solution in step S400 to adjust the pH value of the analytical solution to 4.5, and stirring the analytical solution at a temperature of 60°C and a stirring rate of 25rpm until rebaudioside B crystals are precipitated, filtering the analytical solution using a Buchner funnel to obtain a rebaudioside B filter cake, and drying the rebaudioside B filter cake at 95°C to obtain a high-quality rebaudioside B product.

[0060] In this example, a total of 56.1 g of rebaudioside B product was prepared, in which the content of rebaudioside B in the rebaudioside B product was 97.4 wt %, the content of the remaining steviosides was 0.8 wt %, and the overall recovery rate of rebaudioside B was 91.1%.

[0061] Example 3

[0062] This embodiment provides a method for preparing rebaudioside B using stevia mother liquor sugar, comprising the following steps:

[0063] S100, dissolving 500 g of stevia mother liquid sugar in pure water to obtain a solution; wherein the mass ratio of the stevia mother liquid sugar to pure water is 1:20, and the total glycoside content of the stevia mother liquid sugar is 49.4 wt%, and the rebaudioside B content is 8.2 wt%;

[0064] S200, passing the dissolved solution in step S100 through a polyacrylamide anion exchange resin column, wherein the rebaudioside B in the dissolved solution is adsorbed by the polyacrylamide anion exchange resin, and the remaining stevioside flows out as an effluent; wherein the amount of the polyacrylamide anion exchange resin is 500 ml, the flow rate of the dissolved solution through the polyacrylamide anion exchange resin is 3 BV / h, and the injection amount of the dissolved solution as dry solid content is 100 g / 100 ml of the volume of the polyacrylamide anion exchange resin;

[0065] S300, using 1500 ml of an alkali-alcohol solution as an analytical agent to analyze the rebaudioside B adsorbed by the polyacrylamide anion exchange resin to obtain an analytical solution containing rebaudioside B; wherein the alkali-alcohol solution is a mixed solution of 40 wt% ammonia water and 70 vt% propanol solution, and the volume ratio of the ammonia water to the propanol solution in the alkali-alcohol solution is 1:40, and the flow rate of the alkali-alcohol solution through the polyacrylamide anion exchange resin is 2 BV / h;

[0066] S400, at a temperature of 90° C. and a stirring rate of 100 rpm, concentrating the analytical solution to an alcohol concentration of 40 wt % and a solid content of 20 wt %;

[0067] S500, adding 30wt% acetic acid to the concentrated analytical solution in step S400 to adjust the pH value of the analytical solution to 3.5, and stirring the analytical solution at a temperature of 45°C and a stirring rate of 50rpm until rebaudioside B crystals are precipitated, filtering the analytical solution using a Buchner funnel to obtain a rebaudioside B filter cake, and drying the rebaudioside B filter cake at 80°C to obtain a high-quality rebaudioside B product.

[0068] In this example, a total of 38.2 g of rebaudioside B product was prepared. Figure 1 As shown, after liquid chromatography detection, the content of rebaudioside B in the rebaudioside B product is 97.1wt%, and the content of other steviosides is 1.1wt%. The overall recovery rate of rebaudioside B is 90.5%.

[0069] Example 4

[0070] This embodiment provides a method for preparing rebaudioside B using stevia mother liquor sugar, comprising the following steps:

[0071] S100, dissolving 500 g of stevia mother liquid sugar in pure water to obtain a solution; wherein the mass ratio of the stevia mother liquid sugar to pure water is 1:35, and the total glycoside content of the stevia mother liquid sugar is 45.7 wt%, and the rebaudioside B content is 6.5 wt%;

[0072] S200, passing the dissolved solution in step S100 through a strong basic anion exchange resin column, wherein the rebaudioside B in the dissolved solution is adsorbed by the strong basic anion exchange resin, and the remaining stevioside flows out as an effluent; wherein the dosage of the strong basic anion exchange resin is 520 ml, the column flow rate of the dissolved solution in the strong basic anion exchange resin is 3 BV / h, and the injection amount of the dissolved solution as dry solid content is 96 g / 100 ml of the volume of the strong basic anion exchange resin;

[0073] S300, using 1000 ml of an alkali-alcohol solution as an analytical agent to analyze the rebaudioside B adsorbed by the strong basic anion exchange resin to obtain an analytical solution containing rebaudioside B; wherein the alkali-alcohol solution is a mixed solution of 45 wt% ammonia water and 80 vt% ethanol solution, and the volume ratio of the ammonia water to the propanol solution in the alkali-alcohol solution is 1:30, and the flow rate of the alkali-alcohol solution through the column in the strong basic anion exchange resin is 2 BV / h;

[0074] S400, at a temperature of 75° C. and a stirring rate of 70 rpm, concentrating the analytical solution to an alcohol concentration of 25 wt % and a solid content of 12 wt %;

[0075] S500, adding 35wt% acetic acid to the concentrated analytical solution in step S400 to adjust the pH value of the analytical solution to 4.0, and stirring the analytical solution at a temperature of 50°C and a stirring rate of 60rpm until rebaudioside B crystals are precipitated, filtering the analytical solution using a Buchner funnel to obtain a rebaudioside B filter cake, and drying the rebaudioside B filter cake at 70°C to obtain a high-quality rebaudioside B product.

[0076] In this example, a total of 29.3 g of rebaudioside B product was prepared, in which the content of rebaudioside B in the rebaudioside B product was 96.8 wt %, the content of the remaining steviosides was 1.4 wt %, and the overall recovery rate of rebaudioside B was 87.3%.

[0077] Comparative Example 1

[0078] The method for preparing rebaudioside B using stevia mother liquor sugar provided in this comparative example is basically the same as that in Example 1, except that, in step S300, the 60vt% methanol solution in the alkaline alcohol solution is replaced by an equal amount of 30wt% NaOH solution as a decomposing agent, and the rebaudioside B adsorbed by the strong alkaline anion exchange resin is decomposed to obtain a decomposition solution, and the concentration of the NaOH solution is the same as that in Example 1.

[0079] In this comparative example, a total of 6.8 g of rebaudioside B product was prepared, in which the content of rebaudioside B in the rebaudioside B product was 93.5 wt %, the content of the remaining steviosides was 0.4 wt %, and the overall recovery rate of rebaudioside B was 41.0%.

[0080] It can be seen that, relative to the alkaline-alcohol solution, the preparation amount of the Rebaudioside B product in this comparative example using NaOH solution as the analytical agent to analyze the Rebaudioside B adsorbed by the anion exchange resin is much lower than 13.8 g of Example 1, and the content of Rebaudioside B in the Rebaudioside B product of this comparative example is much lower than 96.5 wt % of Example 1. This is because the anion exchange resin has a strong adsorption capacity for Rebaudioside B, and the use of alkaline solution as the analytical agent cannot completely analyze the Rebaudioside B adsorbed by the anion exchange resin.

[0081] Comparative Example 2

[0082] The method for preparing rebaudioside B using stevia mother liquor sugar provided in this comparative example is basically the same as that in Example 1, except that, in step S300, the 30wt% NaOH solution in the alkaline alcohol solution is replaced by an equal amount of 60vt% methanol solution as a decomposing agent, and the rebaudioside B adsorbed by the strong alkaline anion exchange resin is decomposed to obtain a decomposition solution, and the concentration of the methanol solution is the same as that in Example 1.

[0083] In this comparative example, a total of 1.2 g of rebaudioside B product was prepared, in which the content of rebaudioside B in the rebaudioside B product was 90.7 wt %, the content of the remaining steviosides was 3.2 wt %, and the overall recovery rate of rebaudioside B was 7.0%.

[0084] It can be seen that, relative to the alkaline alcohol solution, the preparation amount of the rebaudioside B product in this comparative example using methanol solution as a decomposing agent to decompose the rebaudioside B adsorbed by the anion exchange resin is much lower than 13.8g of Example 1, and the content of rebaudioside B in the rebaudioside B product of this comparative example is much lower than 96.5wt% of Example 1. This is because the anion exchange resin has a strong adsorption force on rebaudioside B, and the rebaudioside B adsorbed by the anion exchange resin cannot be decomposed using an alcohol solution as a decomposing agent. Therefore, the present invention obtains an alkaline alcohol solution by mixing 30-50wt% of an alkaline solution and 60-85vt% of an alcohol solution, and uses the alkaline alcohol solution as a decomposing agent to achieve the decomposition of the rebaudioside B adsorbed by the ion exchange resin, thereby obtaining a high-quality rebaudioside B product, and maintaining the overall recovery rate of rebaudioside B above 85%.

[0085] It can be seen from the above embodiments, comparative examples, and test data that under the conditions of the embodiments of the present invention, an alkali-alcohol solution is obtained by mixing 30-50wt% of an alkali solution and 60-85vt% of an alcohol solution, and the alkali-alcohol solution is used as a decomposing agent to achieve the decomposition of rebaudioside B adsorbed by the ion exchange resin, thereby obtaining a high-quality rebaudioside B product, and maintaining the overall recovery rate of rebaudioside B above 85%, thereby solving the technical problems of complex preparation process, harsh reaction conditions, and poor quality of the prepared rebaudioside B in the prior art.

[0086] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0087] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing rebaudioside B using stevia mother liquor sugar, characterized in that: include: Passing the dissolved solution of stevia mother liquor sugar through an anion exchange resin column, so that rebaudioside B in the dissolved solution is adsorbed by the anion exchange resin, and the remaining stevioside flows out as an effluent; The anion exchange resin is resolved by using an alkali alcohol solution to obtain a resolved solution containing rebaudioside B; The pH value of the analytical solution is adjusted to 3-4.5 with an acid solution, and the analytical solution is stirred until rebaudioside B crystals are precipitated. After filtering, the filter cake is dried to obtain a rebaudioside B product.

2. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: The alkali-alcohol solution is a mixed solution of 30-50 wt % alkali solution and 60-85 wt % alcohol solution; wherein the volume ratio of the alkali solution to the alcohol solution in the alkali-alcohol solution is 1:(8-80).

3. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 2, characterized in that: The alkaline solution includes 30-50 wt% NaOH solution, 30-50 wt% KOH solution or 30-50 wt% ammonia solution; and / or, The alcohol solution includes 60-85vt% methanol solution, 60-85vt% ethanol solution or 60-85vt% propanol solution.

4. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: The injection amount of the dissolved solution as dry solid content is 60-120 g / 100 ml of the volume of the anion exchange resin.

5. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: After obtaining the analytical solution containing rebaudioside B and before adjusting the pH value of the analytical solution to 3 to 4.5 with an acid solution, the method further comprises: Under the conditions of a temperature of 50 to 90° C. and a stirring rate of 25 to 100 rpm, the analytical solution is concentrated to an alcohol concentration of 10 to 40 wt % and a solid content of 5 to 20 wt %.

6. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: The stevia mother liquid sugar dissolving solution is a mixed solution of stevia mother liquid sugar and pure water, wherein the mass ratio of stevia mother liquid sugar to pure water in the mixed solution is 1:(4-50); and / or, The total glycoside content in the stevia mother liquor sugar is 40-60wt%, and the remainder is impurities; wherein the content of rebaudioside B in the total glycosides is 3-12wt%.

7. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: In the process of adjusting the pH value of the analytical solution to 3-4.5 with an acid solution, the concentration of the acid solution is 5-40 wt %; and / or, The acid solution includes 5-40 wt % of hydrochloric acid, 5-40 wt % of nitric acid or 5-40 wt % of acetic acid.

8. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: The analytical solution is concentrated until rebaudioside B crystals are precipitated, and the temperature during the crystallization is 30-60° C. and the stirring rate is 25-100 rpm.

9. The method for preparing rebaudioside B using stevia mother liquor sugar according to claim 1, characterized in that: The temperature during the drying of the filter cake is 65-95°C.

10. A rebaudioside B product, characterized in that: The method for preparing rebaudioside B using stevia mother liquor sugar according to any one of claims 1 to 9, wherein the rebaudioside B content in the rebaudioside B product is greater than 96wt%, the content of other steviosides is less than 2wt%, the remainder is flavonoid compounds, and the overall recovery rate of rebaudioside B is greater than 85%.

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