Method for recovering stevioside mixture and rebaudioside B in stevia mother liquor sugar

Abstract

The invention discloses a method for recovering a stevioside mixture and rebaudioside B in stevia mother liquor sugar, which comprises the following steps: dissolving the stevia mother liquor sugar in purified water to obtain a stevia mother liquor sugar solution; adding a pH regulator into the stevia mother liquor sugar solution to regulate the pH to 6.5-7.0 to obtain a to-be-treated solution; performing primary filtration on the to-be-treated liquid by adopting a hollow fiber membrane, and adding purified water into trapped fluid for washing to obtain trapped fluid and permeated fluid; sequentially carrying out vacuum concentration and spray drying on the permeate to obtain a stevioside mixture; and heating the trapped fluid, adjusting the pH value to 4.5-5.0, carrying out sedimentation treatment, filtering while the trapped fluid is hot, and drying a filter cake to obtain a rebaudioside B product. The stevioside mixture with high total glycoside content, the rebaudioside B and the feed additive are prepared by taking the stevia mother liquor sugar as a raw material, the economic value of the stevia mother liquor sugar is improved, and the method is simple in process flow, easy to operate and suitable for industrial large-scale production and has remarkable economic benefits and social benefits.

Description

Technical Field

[0001] The invention relates to the technical field of stevioside recovery, and in particular to a method for recovering a stevioside mixture and rebaudioside B in stevia mother liquor sugar. Background Art

[0002] Stevioside is a modern new natural sweetener extracted from the leaves of Stevia, 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 an effective ingredient isolated from Stevia, and its sweetness is 150 times that of sucrose. The sweetness of Rebaudioside B is weaker than that of Rebaudioside A, but the bitterness after taste is significantly weaker than that of Rebaudioside A. Therefore, the taste of Rebaudioside B is significantly better than that of Rebaudioside A. In addition to being a sweetener, studies have found that Rebaudioside B also has the effects of regulating blood sugar and blood lipids, relieving constipation, and promoting metabolism. It can be used to assist in the treatment of diseases such as diabetes and hyperlipidemia. It is a steviol glycoside compound with great application potential.

[0003] The traditional preparation process of rebaudioside B is to hydrolyze rebaudioside A. Although this method can produce a high content of rebaudioside B, the raw material price is high. At present, a part of stevioside mother liquor sugar is produced in the preparation of steviol glycosides. The total glycoside content of the mother liquor sugar is low, the taste is not good, and the economic value is low, but this type of mother liquor sugar contains a certain amount of rebaudioside B. Therefore, recovering rebaudioside B from the mother liquor sugar will not only increase the economic value of the mother liquor sugar, but also reduce the preparation cost of rebaudioside B. At present, the method for recovering rebaudioside B from stevioside mother liquor sugar mainly uses macroporous adsorption resin to adsorb steviol glycosides in the mother liquor sugar solution, and then uses ethanol solutions of different concentrations for elution, collects the eluate in sections, concentrates and precipitates to obtain crude stevioside, and then uses solvents for refining. In the above method, the amount of waste liquid generated is large, the separation effect is not good, and the solvent recovery is difficult. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the shortcomings of the prior art, a method for recovering a stevioside mixture and rebaudioside B in stevioside mother liquid sugar is provided. The present invention uses stevioside mother liquid sugar as a raw material and utilizes the high-efficiency separation characteristics of a hollow fiber membrane to achieve the preliminary separation of the stevioside mixture, rebaudioside B and most impurities, and then acid precipitation is performed under certain conditions to obtain a stevioside mixture with a high total glycoside content, rebaudioside B and a feed additive, thereby improving the economic value of the stevioside mother liquid sugar. The entire process is simple and easy to operate, and is suitable for industrial large-scale production, with significant economic and social benefits.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar comprises the following steps:

[0007] (1) Raw material dissolution:

[0008] Dissolving stevia mother liquid sugar in purified water to obtain a stevia mother liquid sugar solution;

[0009] (2) pH adjustment:

[0010] Adding a pH adjuster to the above stevia mother liquid sugar solution to adjust the pH of the solution to 6.5-7.0 to obtain a solution to be treated;

[0011] (3) Hollow fiber membrane separation:

[0012] The liquid to be treated is filtered once using a hollow fiber membrane, and purified water is added to the retentate for washing to obtain a retentate and a permeate;

[0013] (4) Preparation of Stevioside:

[0014] The permeate is first vacuum concentrated and then spray dried to obtain a high-content stevioside mixture;

[0015] (5) Preparation of rebaudioside B:

[0016] The retentate is heated and its pH is adjusted to 4.5-5.0, and subjected to sedimentation treatment. After the treatment, it is filtered while hot and the filter cake is dried to obtain the rebaudioside B product.

[0017] Preferably, in step (1), the concentration of the stevia mother liquor sugar solution is 0.1-0.2 g / ml.

[0018] Preferably, in step (2), the pH regulator is one of calcium oxide and calcium hydroxide.

[0019] Preferably, in step (3), the hollow fiber membrane model used for filtration is NF-10-20; the material of the hollow fiber membrane is polyvinylidene fluoride, the membrane operating pressure is 0.3-0.5 MPa, and after the membrane runs for 20-40 minutes, the permeate is reversely fed for 30-60 seconds.

[0020] Preferably, in step (3), when the retentate is filtered to 10-15% of the original volume, purified water is added to the retentate, and the amount of purified water added is half of the volume of the retentate, and this is repeated 2-3 times.

[0021] Preferably, in step (4), the temperature of vacuum concentration is 60-80° C., the vacuum degree is -0.06 to -0.1 MPa, and the solid content of the concentrate after vacuum concentration is 30-55 wt %.

[0022] Preferably, in step (4), the air inlet temperature during spray drying is 160-190°C, and the air outlet temperature is 70-95°C.

[0023] Preferably, in step (5), the temperature of the sedimentation treatment is 75-90° C. and the time is 1-3 h.

[0024] Preferably, in step (5), one of hydrochloric acid, acetic acid and citric acid is used to adjust the pH.

[0025] Preferably, in step (5), the filter cake is washed 1-2 times with purified water during filtration, and the eluent and the filtrate are combined and dried to obtain the feed additive.

[0026] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] 1. The present invention uses stevia mother liquor sugar as raw material, and separates rebaudioside B from other steviol glycosides by combining hollow fiber membrane separation, acid precipitation and other technologies, thereby obtaining a stevia glycoside mixture with a high total glycoside content and rebaudioside B, and obtaining a by-product feed additive, thereby improving the economic value of stevia mother liquor sugar.

[0028] 2. The present invention dissolves stevia mother liquor sugar in water and effectively adjusts the pH of the solution, and then uses hollow fiber membrane separation. Based on the high-efficiency separation characteristics of the hollow fiber membrane and reasonable adjustment of the separation conditions, the preliminary separation of the stevioside mixture from rebaudioside B and most impurities is achieved, thereby ensuring the high purity of the stevioside mixture product.

[0029] 3. The present invention effectively adjusts the temperature and pH value when rebaudioside B is precipitated, effectively promotes the precipitation and purification of rebaudioside B, and improves the yield and purity of the product. The present invention also recycles the feed additives prepared from the waste liquid in the process, further improving the economic value of stevia mother liquor sugar.

[0030] 4. The whole process of the present invention is simple, easy to operate, and suitable for industrial large-scale production, and has significant economic and social benefits. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0033] In the following examples and comparative examples, unless otherwise specified, the raw materials are all commercially available and the conditions are all conventional technical conditions in the art.

[0034] Example 1

[0035] A method for recovering a steviol glycoside mixture and rebaudioside B from stevia mother liquor sugar; comprising the following steps:

[0036] (1) dissolving 2.0 kg of stevia mother liquor sugar (total glycoside content: 60.5 wt %, rebaudioside B content: 3.9 wt %) in 10 L of purified water to obtain a stevia mother liquor sugar solution;

[0037] (2) adding calcium oxide to the above-mentioned stevia mother liquid sugar to adjust the solution pH to 6.5 to obtain a solution to be treated;

[0038] (3) The treated liquid was filtered using a polyvinylidene fluoride hollow fiber membrane (Singapore Sanyi Membrane Technology Co., Ltd., membrane model NF-20) at a membrane pressure of 0.3 MPa. The membrane was run for 40 minutes, and the permeate was reverse-fed for 60 seconds. When the concentrate was concentrated to 10% of the original volume, 1 / 2 volume of purified water was added to the concentrate, and the filtration was continued. This was repeated twice, and the retentate and permeate were collected;

[0039] (4) The permeate was concentrated at 60° C. and vacuum degree of −0.1 MPa to obtain a concentrate with a solid content of 55 wt %. The concentrate was spray-dried (inlet temperature 190° C., outlet temperature 95° C.) to obtain 1277 g of a high-content steviol glycoside mixture (total glycoside content 85.5 wt %).

[0040] (5) The retentate was heated to 75° C., hydrochloric acid was added to adjust the pH value of the solution to 4.5, and the precipitation was carried out for 3 hours. After the precipitation was completed, the solution was filtered while hot, and the precipitate was washed with purified water. The filter cake was dried to obtain 72.1 g of rebaudioside B product with a rebaudioside B content of 95.4 wt% and a yield of 88.2%. The washing liquid and the filtrate were mixed and dried to obtain a feed additive.

[0041] Example 2

[0042] A method for recovering a steviol glycoside mixture and rebaudioside B from stevia mother liquor sugar; comprising the following steps:

[0043] (1) dissolving 2.0 kg of stevia mother liquor sugar (total glycoside content: 74.5 wt %, rebaudioside B content: 14.1 wt %) in 20 L of purified water to obtain a stevia mother liquor sugar solution;

[0044] (2) adding calcium hydroxide to the above-mentioned stevia mother liquid sugar to adjust the solution pH to 7.0 to obtain a solution to be treated;

[0045] (3) The treated liquid was filtered using a polyvinylidene fluoride hollow fiber membrane (Singapore Sanyi Membrane Technology Co., Ltd., membrane model NF-10) at a membrane pressure of 0.5 MPa. The permeate was fed back for 30 seconds every 20 minutes of membrane operation. When the concentrate was concentrated to 15% of the original volume, 1 / 2 volume of purified water was added to the concentrate and the filtration was continued. This was repeated 3 times, and the retentate and permeate were collected.

[0046] (4) The permeate was concentrated at 80° C. and vacuum degree of −0.06 MPa to obtain a concentrate with a solid content of 30 wt %. The concentrate was spray-dried (inlet temperature 165° C., outlet temperature 70° C.) to obtain 1356 g of a high-content steviol glycoside mixture (total glycoside content 86.3 wt %).

[0047] (5) The retentate was heated to 90° C., acetic acid was added to adjust the pH value of the solution to 5.0, and the precipitation was carried out for 1 hour. After the precipitation was completed, the solution was filtered while hot, and the precipitate was washed with purified water. The filter cake was dried to obtain 259.6 g of rebaudioside B product with a rebaudioside B content of 96.0 wt% and a yield of 88.4%. The washing liquid and the filtrate were mixed and dried to obtain a feed additive.

[0048] Example 3

[0049] A method for recovering a steviol glycoside mixture and rebaudioside B from stevia mother liquor sugar; comprising the following steps:

[0050] (1) dissolving 2.0 kg of stevia mother liquor sugar (total glycoside content: 67.1 wt %, rebaudioside B content: 6.2 wt %) in 17 L of purified water to obtain a stevia mother liquor sugar solution;

[0051] (2) adding calcium oxide to the above-mentioned stevia mother liquid sugar to adjust the solution pH to 6.7 to obtain a solution to be treated;

[0052] (3) The treated liquid was filtered using a polyvinylidene fluoride hollow fiber membrane (Singapore Sanyi Membrane Technology Co., Ltd., membrane model NF-15) at a membrane pressure of 0.4 MPa. The membrane was run for 30 minutes, and the permeate was fed back for 40 seconds. When the concentrate was concentrated to 12% of the original volume, 1 / 2 volume of purified water was added to the concentrate, and the filtration was continued. This was repeated twice, and the retentate and permeate were collected;

[0053] (4) The permeate was concentrated at a temperature of 65° C. and a vacuum degree of −0.09 MPa to obtain a concentrate having a solid content of 42 wt %. The concentrate was spray-dried (inlet temperature of 175° C., outlet temperature of 78° C.) to obtain 1378 g of a high-content steviol glycoside mixture (total glycoside content of 85.8 wt %).

[0054] (5) The retentate was heated to 81° C., citric acid was added to adjust the pH value of the solution to 4.7, and the solution was precipitated for 2 h. After the precipitation was completed, the solution was filtered while hot, and the precipitate was washed with purified water. The filter cake was dried to obtain 114.3 g of rebaudioside B product with a rebaudioside B content of 95.5 wt% and a yield of 88.0%. The washing solution and the filtrate were mixed and dried to obtain a feed additive.

[0055] Example 4

[0056] A method for recovering a steviol glycoside mixture and rebaudioside B from stevia mother liquor sugar; comprising the following steps:

[0057] (1) dissolving 2.0 kg of stevia mother liquor sugar (total glycoside content: 72.3 wt %, rebaudioside B content: 10.8 wt %) in 13 L of purified water to obtain a stevia mother liquor sugar solution;

[0058] (2) adding calcium hydroxide to the above-mentioned stevia mother liquid sugar to adjust the solution pH to 6.8 to obtain a solution to be treated;

[0059] (3) The treated liquid was filtered using a polyvinylidene fluoride hollow fiber membrane (Singapore Sanyi Membrane Technology Co., Ltd., membrane model NF-15) at a membrane pressure of 0.4 MPa. The permeate was reverse-fed for 50 seconds every 30 minutes of membrane operation. When the concentrate was concentrated to 13% of the original volume, 1 / 2 volume of purified water was added to the concentrate and the filtration was continued. This was repeated 3 times, and the retentate and permeate were collected.

[0060] (4) The permeate was concentrated at a temperature of 75° C. and a vacuum degree of −0.07 MPa to obtain a concentrate having a solid content of 51 wt %. The concentrate was spray-dried (inlet temperature of 186° C., outlet temperature of 86° C.) to obtain 1401 g of a high-content steviol glycoside mixture (total glycoside content of 86.5 wt %).

[0061] (5) The retentate was heated to 86° C., hydrochloric acid was added to adjust the pH value of the solution to 4.8, and the precipitation was carried out for 2 h. After the precipitation was completed, the solution was filtered while hot, and the precipitate was washed with purified water. The filter cake was dried to obtain 202.2 g of rebaudioside B product with a rebaudioside B content of 96.2 wt% and a yield of 90.1%. The washing liquid and the filtrate were mixed and dried to obtain a feed additive.

[0062] Comparative Example 1

[0063] Compared with Example 4, the difference is that the concentration of the stevia mother liquor sugar solution is 0.3 g / ml, and the other conditions are the same as Example 4, and 1338 g of a high-content stevioside mixture (total glycoside content 85.2 wt%) is obtained; 185.1 g of rebaudioside B product, the rebaudioside B content is 92.4 wt%, and the yield is 79.2%.

[0064] Comparative Example 2

[0065] Compared with Example 4, the difference is that the pH of the liquid to be treated is 5.5, and the other conditions are the same as those in Example 4, and 1517g of a high-content stevioside mixture (total glycoside content 80.1wt%) and 167.6g of rebaudioside B product are obtained, with a rebaudioside B content of 94.3wt% and a yield of 73.2%.

[0066] Comparative Example 3

[0067] Compared with Example 4, the difference is that the pH of the liquid to be treated is 8.0, and the other conditions are the same as those in Example 4, and 1354g of a high-content stevioside mixture (total glycoside content 86.3wt%) and 203.9g of rebaudioside B product are obtained, with a rebaudioside B content of 91.4wt% and a yield of 86.3%.

[0068] Comparative Example 4

[0069] Compared with Example 4, the difference is that in step (3), the membrane pressure is 0.2 MPa, and the other conditions are the same as those in Example 4, and 1327 g of a high-content stevioside mixture (total glycoside content: 86.1 wt%) and 191.0 g of rebaudioside B product are obtained, with a rebaudioside B content of 90.7 wt% and a yield of 80.2%.

[0070] Comparative Example 5

[0071] Compared with Example 4, the difference is that in step (3), the permeate is not used for reverse feeding, and the other conditions are the same as those in Example 4, and 1295g of a high-content stevioside mixture (total glycoside content: 85.2wt%) and 192.8g of rebaudioside B product are obtained, with a rebaudioside B content of 90.9wt% and a yield of 81.1%.

[0072] Comparative Example 6

[0073] Compared with Example 4, the difference is that in step (3), purified water is not used for washing, and the product is directly concentrated to 13% of the original volume. The other conditions are the same as those in Example 4, and 1106g of a high-content stevioside mixture (total glycoside content: 86.1wt%) and 176.4g of rebaudioside B product are obtained. The rebaudioside B content is 92.4wt% and the yield is 75.5%.

[0074] Comparative Example 7

[0075] Compared with Example 4, the difference is that in step (5), the pH during precipitation treatment is 4.0, and the other conditions are the same as those in Example 4, and 1399 g of a high-content stevioside mixture (total glycoside content: 86.0 wt%) and 243.0 g of rebaudioside B product are obtained, with a rebaudioside B content of 83.1 wt% and a yield of 93.5%.

[0076] Comparative Example 8

[0077] Compared with Example 4, the difference is that in step (5), the pH during precipitation treatment is 6.0, and the other conditions are the same as those in Example 4, and 1411 g of a high-content stevioside mixture (total glycoside content: 85.9 wt%) and 162.1 g of rebaudioside B product are obtained, with a rebaudioside B content of 96.1 wt% and a yield of 72.1%.

[0078] Comparative Example 9

[0079] Compared with Example 4, the difference is that in step (5), the temperature during precipitation treatment is 60°C, and the other conditions are the same as those in Example 4, and 1398g of a high-content stevioside mixture (total glycoside content: 86.4wt%) and 218.9g of rebaudioside B product are obtained, with a rebaudioside B content of 91.5wt% and a yield of 92.7%.

[0080] Comparative Example 10

[0081] Compared with Example 4, the difference is that in step (5), the temperature during precipitation treatment is 95°C, and the other conditions are the same as those in Example 4, and 1405g of a high-content stevioside mixture (total glycoside content: 86.1wt%) and 188.7g of rebaudioside B product are obtained, with a rebaudioside B content of 96.0wt% and a yield of 83.9%.

[0082] In summary, compared with the comparative example, the present invention obtains a steviol glycoside mixture with a high total glycoside content and a high content of rebaudioside B by optimizing various conditions in the treatment process, thereby improving the economic value of stevia mother liquor sugar, and the amount of waste liquid generated in the whole process is small, which is energy-saving and environmentally friendly.

[0083] Compared with the embodiment of the present invention, in Comparative Example 1, when the solid content of the stevia mother liquid sugar solution is large, the yield of the stevioside mixture and the yield of rebaudioside B are significantly reduced, and the purity is also reduced, mainly because when the solid content of the stevia mother liquid sugar solution is large, the separation effect is not good when the hollow fiber membrane is used for separation. In Comparative Examples 2 and 3, the pH of the stevia mother liquid sugar solution is too high or too low, and the yield and purity of the stevioside mixture and rebaudioside B are affected, because under the condition of too high pH, ​​too much calcium salt is added, which will cause other steviosides or impurities other than rebaudioside B to combine with calcium ions, and under the condition of too low pH, rebaudioside B in the stevia mother liquid sugar cannot be fully complexed with calcium ions.

[0084] When the hollow fiber membrane is used to treat the liquid to be treated, the filtration and concentration conditions are also extremely critical. In Comparative Example 4, the membrane pressure is too small, and some impurities will be retained by the hollow fiber membrane together with the complexed rebaudioside B. In Comparative Example 5, during the filtration and concentration process, if the permeate is not used for backfeeding to achieve the purpose of backflushing the hollow fiber membrane, the hollow fiber membrane will be blocked, thereby affecting its filtration efficiency, reducing the purity of rebaudioside B and the yield of the stevioside mixture. In Comparative Example 6, the stevioside mixture in the retained liquid cannot be fully separated, which not only reduces the yield of the stevioside mixture, but also reduces the purity of rebaudioside B; and if it is not washed, other steviosides will act as impurities, affecting the precipitation of rebaudioside B, and then affecting the content of rebaudioside B.

[0085] When separating and purifying rebaudioside B in the retentate, temperature and pH are critical. In Comparative Example 7, under the condition of too low pH, other impurities will precipitate together with rebaudioside B; in Comparative Example 8, under the condition of too high pH, ​​rebaudioside B cannot be fully precipitated; in Comparative Example 9, the precipitation temperature is too low, impurities will precipitate together with rebaudioside B; and if the precipitation temperature is too high, rebaudioside B cannot be fully precipitated.

[0086] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for recovering a mixture of steviol glycosides and rebaudioside B from stevia mother liquor sugar, characterized in that: The following steps are involved: (1) Raw material dissolution: Dissolving stevia mother liquid sugar in purified water to obtain a stevia mother liquid sugar solution; (2) pH adjustment: Adding a pH adjuster to the above stevia mother liquid sugar solution to adjust the pH of the solution to 6.5-7.0 to obtain a solution to be treated; (3) Hollow fiber membrane separation: The liquid to be treated is filtered once using a hollow fiber membrane, and purified water is added to the retentate for washing to obtain a retentate and a permeate; (4) Preparation of Stevioside Mixture: The permeate is first vacuum concentrated and then spray dried to obtain a high-content stevioside mixture; (5) Preparation of rebaudioside B: The retentate in step (3) is heated and its pH is adjusted to 4.5-5.0, and subjected to sedimentation treatment. After the treatment, it is filtered while hot and the filter cake is dried to obtain the rebaudioside B product.

2. The method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar according to claim 1, characterized in that: In step (1), the concentration of the stevia mother liquor sugar solution is 0.1-0.2 g / ml.

3. The method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar according to claim 1, characterized in that: In step (2), the pH regulator is one of calcium oxide and calcium hydroxide.

4. The method for separating and recovering a mixture of steviol glycosides and rebaudioside B from stevia mother liquor sugar by using a hollow fiber membrane according to claim 1, characterized in that: In step (3), the model of the hollow fiber membrane used for filtration is NF-10-20; the material of the hollow fiber membrane is polyvinylidene fluoride, the membrane operating pressure is 0.3-0.5MPa, and after the membrane runs for 20-40 minutes, the permeate is reversely fed for 30-60 seconds.

5. The method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar according to claim 1, characterized in that: In step (3), when the retentate is filtered to 10-15% of the original volume, purified water is added to the retentate, and the amount of purified water added is half of the volume of the retentate, and this is repeated 2-3 times.

6. The method for recovering a steviol glycoside mixture and rebaudioside B from stevia mother liquor sugar according to claim 1, characterized in that: In step (4), the temperature of vacuum concentration is 60-80° C., the vacuum degree is -0.06 to -0.1 MPa, and the solid content of the concentrated solution after vacuum concentration is 30-55 wt %.

7. The method for recovering a steviol glycoside mixture and rebaudioside B from stevia mother liquor sugar according to claim 1, characterized in that: In step (4), the air inlet temperature during spray drying is 160-190°C, and the air outlet temperature is 70-95°C.

8. The method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar according to claim 1, characterized in that: In step (5), the temperature of the sedimentation treatment is 75-90° C. and the time is 1-3 h.

9. The method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar according to claim 1, characterized in that: In step (5), the pH is adjusted using one of hydrochloric acid, acetic acid and citric acid.

10. The method for recovering a steviol glycoside mixture and rebaudioside B in stevia mother liquor sugar according to claim 1, characterized in that: In step (5), during filtration, the filter cake is washed 1-2 times with purified water, and the eluent and the filtrate are combined and dried to obtain the feed additive.