Preparation method of glucosyl stevioside

Abstract

The invention belongs to the technical field of stevioside production, and discloses a preparation method of glucosyl stevioside, which comprises the following steps: adding enzyme into stevioside and a glycosyl donor in a reaction system to prepare the glucosyl stevioside; inactivating after the reaction is completed, and cooling to room temperature to obtain a conversion solution; the method comprises the following steps: adding 0.01% by volume of hydrolase for hydrolysis, separating through an ultrafiltration membrane to obtain membrane trapped fluid, concentrating and drying the membrane trapped fluid, adding ethanol for redissolving, adding diatomite for adsorbing impurities, filtering, concentrating and dealcoholizing the obtained clear liquid, and drying to obtain the glucosyl stevioside product. According to the product disclosed by the invention, the production of glucosyl stevioside total glycosides is improved, the proportion of the whole glycosylation chain length is regulated and controlled, the sweetness and sweetness of the mouth feel are improved, the solubility of the glucosyl stevioside total glycosides in application is also increased, the problem of clarification of the glucosyl stevioside total glycosides in a high-alcohol state is solved, and the market application range is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of stevioside production, and particularly relates to a method for preparing glucose-syl stevioside. Background Art

[0002] Glucosyl stevioside (enzyme modified) is a food additive obtained by glucosylating stevioside extracted from stevioside by enzymatic method, and then evaporating, concentrating and spray drying. The sweetness of Glucosyl stevioside is 250 to 450 times that of sucrose, with a slight astringent taste, moderately delicious, and less aftertaste in pure products. It is the natural sweetener closest to sugar.

[0003] Glucosyl stevioside is used as flavoring agent or flavor modifier in alcoholic beverages. It has good solubility in water, but it will precipitate or become unclear foggy in high-dosage ethanol solution or during high-concentration alcohol mixing, which seriously affects the quality of the product. In the production process of glucose-based stevioside in the prior art, macroporous adsorption resin is usually used as a purification method, and the conversion material is adsorbed by resin to absorb stevioside and glycosylated stevioside, and impurities are removed by washing with water or organic solvent containing water, and then the adsorbed glycoside and glycosylated glycoside are analyzed by organic solvent. This process requires sufficient adsorption resin for adsorption in the continuous production link, and the production process causes poor production periodicity and solvent consumption and loss through adsorption, impurity removal, and analysis.

[0004] Different glycosylation donors are prone to adsorption of impurities during the resin removal process or incomplete removal of dextrin during the removal process, resulting in residual impurities, affecting the subsequent purification purity. The residual impurities will also affect the actual application of the product. In addition, the current production process has a relatively high content of long-chain glycosylation products in the products. Long-chain glycosylation products will not only affect the sweetness and solubility, but also affect the taste characteristics of the product during the application process. Therefore, it is necessary to find a better preparation method. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing glucose-based steviol glycosides, which overcomes the defects in the prior art, and uses double enzymes to hydrolyze the sugar chain length of glycosylated steviol glycosides, and the monosaccharides and oligosaccharides produced by hydrolysis are removed through an ultrafiltration membrane, thereby avoiding the subsequent impact on purification. At the same time, by controlling the hydrolysis reaction conditions without changing the structure of steviol glycosides, this method can effectively control the chain length of the glycosylated product, improve the solubility and sensory properties of the product in special application scenarios, and at the same time, remove residual dextrin and protein through subsequent refining and purification, thereby increasing the product content.

[0006] In order to solve the above technical problems, the technical solution of the present invention is:

[0007] A method for preparing glucosyl steviol glycoside comprises the following steps:

[0008] a. Conversion: adding enzymes to the reaction system of stevioside and glycosyl donor to prepare glucose-syl stevioside; after the reaction is completed, inactivation is performed and the reaction is cooled to room temperature to obtain a conversion solution;

[0009] The total glycoside of the steviol glycoside is ≥90%, the glycosyl donor is β-cyclodextrin or maltodextrin (DE value 10-15); the weight ratio of steviol glycoside to glycosyl donor is 0.5-1:1; the enzyme is cyclodextrin glucosyltransferase, the enzyme addition amount is 1-2% of the weight of steviol glycoside, the reaction temperature is 75-80°C, the reaction time is 24-48h; the stirring speed is 100-200rpm, the pH value is 6-7; the concentration of the reaction system is 20%-30%, the reaction solvent is water; the inactivation temperature is 95°C, and the inactivation time is 20-30min;

[0010] b. Hydrolysis: adding 0.01% volume of hydrolase to the conversion solution obtained in step a, hydrolyzing for 24 to 32 hours at a temperature of 20 to 25 ° C, a pH value of 6 to 7, and a stirring speed of 20 rpm to obtain a hydrolyzate; the hydrolase is pullulanase and saccharifying enzyme, each of which is added to 0.01% volume of the conversion solution;

[0011] c. Impurity separation: The hydrolyzate obtained in step b is separated and hydrolyzed by an ultrafiltration membrane (monosaccharides and oligosaccharides in the hydrolyzate are removed); the ultrafiltration membrane is an ultrafiltration membrane with a pore size of 0.02 microns, and water is added when the ultrafiltration clear liquid penetrates to half the volume of the material, the amount of water added is 1 times that of the conversion liquid, and the membrane pressure is 2 to 3Mpa; the membrane retentate is obtained;

[0012] d. Concentration: The membrane retentate obtained in step c was concentrated by negative pressure evaporation at a temperature of 70°C to 75°C and a pressure of -0.08 to -0.1 MPa to a solid content of 70% to 75%, and then spray-dried to obtain a dry powder;

[0013] e. Refining: The dry powder obtained in step d is put into an ethanol-water solution with a volume concentration of 80% to 85%, stirred, and diatomaceous earth is added after stirring evenly, and then filtered after standing; the amount of the ethanol solution added is 7 to 8 times the amount of the dry powder added in step c, and the stirring speed is 100 to 200 rpm; the stirring time is 10 to 60 min; 1% diatomaceous earth by volume of the material obtained after the above dry powder is dissolved is added, and the temperature is 20 to 25 ° C. The conditions are allowed to stand for 20 to 60 min, and the clear liquid is filtered;

[0014] f. Concentration: The ethanol in the clear solution obtained in step e was dealcoholized by negative pressure evaporation and concentration, the heating temperature was 70 to 75 ° C, the pressure was -0.08 to -0.1 MPa, and the solid content was concentrated to 70 to 75% to obtain a concentrate;

[0015] g. Drying: The concentrated solution obtained in step f is spray dried to obtain the finished product of glucosyl stevioside; the spray drying air inlet temperature is 175°C to 180°C, and the air outlet temperature is 85°C to 90°C.

[0016] Preferably, in step a, the glycosyl donor is maltodextrin; the weight ratio of stevioside to dextrin is 1:1; the enzyme addition amount is 1% of the weight of stevioside, the reaction temperature is 80°C, and the reaction time is 24h; the stirring speed is 120rpm, and the pH value is 5.5; the reaction system concentration is 20%, and the reaction solvent is water; the inactivation temperature is 95°C, and the inactivation time is 20min.

[0017] Preferably, in the step b, hydrolysis is carried out for 30 hours at a temperature of 25° C., a pH value of 6.5, and a stirring speed of 20 rpm to obtain a hydrolyzate.

[0018] Preferably, the transmembrane pressure in step c is 2.5 MPa.

[0019] Preferably, in step d, the evaporation temperature is 75° C. and the pressure is -0.1 MPa, until the solid content reaches 70%.

[0020] Preferably, the volume concentration of the ethanol solution in step e is 80%, and the amount of ethanol solution added is 7 times the weight of the dry powder obtained in step c; the stirring speed is 120 rpm; the stirring time is 30 min; the temperature is 25° C., and the standing time is 20 min.

[0021] Preferably, in the step f, the heating temperature is 75° C., the pressure is -0.1 MPa, and the concentrate is concentrated to a solid content of 70%.

[0022] Preferably, in step g, the spray drying air inlet temperature is 180°C and the air outlet temperature is 85°C.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] The present invention adopts a hydrolase to hydrolyze the sugar chain at the non-reducing end of the material in the conversion liquid, thereby reducing the glycosylation ratio of the polysaccharide chain length; by simultaneously performing hydrolysis with a double hydrolase, the sugar chain length of the glucosyl stevioside can be selectively and purposefully regulated; by filtering with an ultrafiltration membrane, the monosaccharides and oligosaccharides produced by the hydrolysis are removed, and finally a glucosyl stevioside product rich in 1-5 glucosylations is obtained; the product has a great improvement in both sweetness and taste application, and a product with a final concentration of 20% can remain in a clear state for 24 hours in a 60% alcohol solution, which is greatly improved compared with the product obtained by the prior art.

[0025] In summary, the present invention not only improves the production of total glucosyl stevioside, regulates the overall glycosylation chain length ratio, improves the sweetness and sweetness of the taste, but also increases its solubility in application, alleviates its clarification problem in a high alcohol state, and expands the scope of market application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Liquid chromatogram of the product of Example 1 of the present invention;

[0027] Figure 2 Liquid chromatogram of the product of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with embodiments:

[0029] Embodiment 1:

[0030] a. Conversion: 100g of stevioside RA97 (Zhucheng Haotian Pharmaceutical Co., Ltd.) and 100g of maltodextrin were added and fixed to 1L of water, heated at 75°C, stirred and suspended, the pH value was adjusted to 6.5, stirred at 120rpm for reaction, 1ml of cyclodextrin glucosyltransferase was added, and the temperature was kept for 24h; after the reaction was completed, the temperature was heated to 95°C, kept warm for 20min, and then cooled to room temperature to obtain a glucose-based stevioside conversion solution;

[0031] b. Hydrolysis: Add 0.01% volume of hydrolase to the conversion solution obtained in step a, and hydrolyze for 30 hours at a temperature of 25°C, a pH value of 6.5, and a stirring speed of 20 rpm to obtain a hydrolyzate; the hydrolase is pullulanase and saccharifying enzyme, each of which is added to 0.01% volume of the conversion solution.

[0032] c. Impurity separation: The hydrolyzate obtained in step b was separated and hydrolyzed by an ultrafiltration membrane; the ultrafiltration membrane was an ultrafiltration membrane with a pore size of 0.02 microns, and water was added when the permeate effluent reached half the volume of the material. The amount of water added was 1 times that of the conversion solution, and the membrane pressure was 2.5 MPa; the membrane retentate was obtained;

[0033] d. Concentration: The membrane retentate obtained in step c was concentrated by negative pressure evaporation at a temperature of 75°C and a pressure of -0.1Mpa to a solid content of 70%, and then spray-dried to obtain a dry powder;

[0034] e. Refining: The dry powder obtained in step d was put into an aqueous ethanol solution with a concentration of 80% by volume, stirred, and diatomaceous earth was added after stirring, and then filtered; the amount of the ethanol solution added was 7 times the weight of the dry powder obtained in step c, and the stirring speed was 120rpm; the stirring time was 30min; 1% diatomaceous earth by volume of the material after the dry powder was dissolved was added, and the temperature was 25°C for 20min, and the clear liquid was filtered;

[0035] f. Concentration: The ethanol in the clear solution obtained in step e was dealcoholized by negative pressure evaporation and concentration, the heating temperature was 75 ° C, the pressure was -0.1Mpa, and the solid content was concentrated to 70% to obtain a concentrate;

[0036] g. Drying: The concentrated solution obtained in step f was spray dried to obtain 113 g of glucosyl stevioside finished product with a yield of 113%; the spray drying air inlet temperature was 180°C and the air outlet temperature was 85°C. The product was then tested by liquid chromatography, and the test results are shown in Figure 1 .

[0037] Embodiment 2:

[0038] a. Conversion: 100g of stevioside RA97 (Zhucheng Haotian Pharmaceutical Co., Ltd.) and 200g of maltodextrin were added and fixed to 1L of water, heated at 75°C, stirred and suspended, the pH value was adjusted to 7, stirred at 100rpm for reaction, 1.5ml of cyclodextrin glucosyltransferase was added, and the temperature was kept for 48h; after the reaction was completed, the temperature was heated to 95°C, kept for 30min and then cooled to room temperature to obtain a glucose-based stevioside conversion solution;

[0039] b. Hydrolysis: Add 0.01% volume of hydrolase to the conversion solution obtained in step a, and hydrolyze for 32 hours at a temperature of 20°C, a pH value of 7, and a stirring speed of 20 rpm to obtain a hydrolyzate; the hydrolase is pullulanase and saccharifying enzyme, each of which is added to 0.01% volume of the conversion solution.

[0040] c. Impurity separation: The hydrolyzate obtained in step b is separated and hydrolyzed by an ultrafiltration membrane; the ultrafiltration membrane is an ultrafiltration membrane with a pore size of 0.02 microns, and water is added when the effluent reaches half the volume of the material, the amount of water added is 1 times that of the conversion liquid, and the membrane pressure is 2Mpa; the membrane retentate is obtained;

[0041] d. Concentration: The membrane retentate obtained in step c was concentrated by negative pressure evaporation at a temperature of 70°C and a pressure of -0.08Mpa to a solid content of 75%, and then spray-dried to obtain a dry powder;

[0042] e. Refining: The dry powder obtained in step d was put into an aqueous ethanol solution with a concentration of 85% by volume, stirred, and after stirring, diatomaceous earth was added and allowed to stand and then filtered; the amount of the ethanol solution added was 8 times the weight of the dry powder obtained in step c, and the stirring speed was 150rpm; the stirring time was 10min; 1% diatomaceous earth by volume of the material after the dry powder was dissolved was added, and the mixture was allowed to stand at a temperature of 25°C for 60min, and the clear liquid was filtered;

[0043] f. Concentration: The ethanol in the clear solution obtained in step e was dealcoholized by negative pressure evaporation and concentration, the heating temperature was 70 ° C, the pressure was -0.08Mpa, and the solid content was concentrated to 75% to obtain a concentrate;

[0044] g. Drying: The concentrated solution obtained in step f was spray dried to obtain 108 g of glucosyl stevioside finished product with a yield of 108%; the spray drying inlet air temperature was 175°C and the outlet air temperature was 90°C.

[0045] Embodiment 3:

[0046] a. Conversion: 100g of stevioside RA97 (Zhucheng Haotian Pharmaceutical Co., Ltd.) and 150g of maltodextrin were added and fixed to 1L of water, heated at 75°C, stirred and suspended, the pH value was adjusted to 6, stirred at 150rpm for reaction, 2ml of cyclodextrin glucosyltransferase was added, and the temperature was kept for 36h; after the reaction was completed, the temperature was heated to 95°C, kept for 25min and then cooled to room temperature to obtain a glucose-based stevioside conversion solution;

[0047] b. Hydrolysis: Add 0.01% volume of hydrolase to the conversion solution obtained in step a, and hydrolyze for 24 hours at a temperature of 25°C, a pH value of 6.5, and a stirring speed of 20 rpm to obtain a hydrolyzate; the hydrolase is pullulanase and saccharifying enzyme, each of which is added to 0.01% volume of the conversion solution.

[0048] c. Impurity separation: The hydrolyzate obtained in step b was separated and hydrolyzed by an ultrafiltration membrane; the ultrafiltration membrane was an ultrafiltration membrane with a pore size of 0.02 microns, and water was added when the effluent reached half the volume of the material, the amount of water added was 1 times that of the conversion liquid, and the membrane pressure was 3Mpa; the membrane retentate was obtained;

[0049] d. Concentration: The membrane retentate obtained in step c was concentrated by negative pressure evaporation at a temperature of 70°C and a pressure of -0.1Mpa to a solid content of 70%, and then spray-dried to obtain a dry powder;

[0050] e. Refining: The dry powder obtained in step d is put into an ethanol solution (ethanol, aqueous solution) with a volume concentration of 80%, stirred, and after stirring evenly, diatomaceous earth is added, allowed to stand, and then filtered; the amount of the ethanol solution added is 8 times the weight of the dry powder material obtained in step c, the stirring speed is 150rpm; the stirring time is 40min; 1% diatomaceous earth by volume of the material after the dry powder is dissolved is added, and the temperature is 25°C for 40min, and the clear liquid is filtered;

[0051] f. Concentration: The ethanol in the clear solution obtained in step e was dealcoholized by negative pressure evaporation and concentration, the heating temperature was 75 ° C, the pressure was -0.1Mpa, and the solid content was concentrated to 70% to obtain a concentrate;

[0052] g. Drying: The concentrated solution obtained in step f was spray dried to obtain 112 g of glucosyl stevioside finished product with a yield of 112%; the spray drying inlet air temperature was 180°C and the outlet air temperature was 85°C.

[0053] Embodiment 4:

[0054] The glycosyl donor maltodextrin in Example 1 was replaced by β-cyclodextrin, and other conditions remained unchanged to obtain 110 grams of product with a yield of 110%.

[0055] Comparative Example 1:

[0056] a. Conversion: Same as Example 1

[0057] b. Impurity separation: The conversion liquid is subjected to dedextrin removal by T28 macroporous adsorption resin. The volume of resin used is 15 times the amount of stevioside added. After feeding, it is washed with 2 times the volume of resin to remove impurities, 2 times the volume of 60% ethanol is used for analysis, and 2 times the volume of water is used for top alcohol. The analysis liquid and top alcohol liquid are collected at the flow rate.

[0058] The steps of concentration, refining and concentration are the same as those in Example 1.

[0059] g. Drying: The concentrated solution obtained in step f was spray dried to obtain 128g of glucosyl stevioside finished product with a yield of 128%; the spray drying air inlet temperature was 180°C and the air outlet temperature was 85°C. The product was then tested by liquid chromatography, and the test results are shown in Figure 2 .

[0060] Comparative Example 2:

[0061] a. The conversion and impurity removal steps are the same as those in Comparative Example 1;

[0062] After impurities are removed, the mixture is directly concentrated. The concentration steps are the same as those in Example 1.

[0063] g. Drying: The concentrated solution obtained in step 1 was spray dried to obtain 133 g of glucosyl stevioside finished product with a yield of 133%; the spray drying inlet air temperature was 180°C and the outlet air temperature was 85°C.

[0064] Result analysis:

[0065] The products obtained after treatment of Examples 1-4 and Comparative Examples 1-2 were analyzed and compared.

[0066] ① The detection method uses the Japanese method of enzyme-modified sugar to detect the total glycoside content and glucosyl stevioside (GSG), and the glycosylation quantity is analyzed according to the proportion of the liquid phase spectrum peak;

[0067] ② The taste score is scored by a 9-person evaluation team. The taste is scored based on multiple dimensions, including sweetness, aftersweetness, sharpness, bitterness, astringency, and miscellaneous flavors. Each dimension is scored 10 points. The evaluation scores are added together and the average is taken to get the overall taste evaluation score. The higher the score, the higher the recognition of the tested sample, which means the taste is better. However, the test data is artificial, and the test method must be made public.

[0068] ③ Comparison of the dissolution and clarification time of 20g product in 85ml 70% ethanol. The results are shown in Table 1:

[0069] Table 1 Comparison of product analysis results of Examples 1-4 and Comparative Examples 1-2

[0070]

[0071] The results of Examples 1-4 and Comparative Examples 1-2 show that:

[0072] In Examples 1-4, the indicators and taste are not much different, but overall Example 1 is the best example.

[0073] In the comparative example, the polysaccharide chain length of the product prepared without hydrolysis is relatively high, resulting in the average molecular weight of the obtained sample being relatively higher than the average molecular weight of the product in the example, and thus having a relative advantage in the final product weight or yield.

[0074] In the comparative examples, the product in comparative example 1 that was not hydrolyzed had a high glycosylation ratio but a low short chain ratio, and the product showed a relatively low score in the taste comparison; while the product in comparative example 2 did not undergo a refining step, and the residual impurities in the product resulted in a significant reduction in the total glycosides. At the same time, the presence of impurities in the product affected its solubility stability in the test.

[0075] It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A method for preparing glucosyl steviol glycoside, characterized in that: The following steps are involved: a. Conversion: adding enzymes to the reaction system of stevioside and glycosyl donor to prepare glucose-syl stevioside; after the reaction is completed, inactivation is performed and the reaction is cooled to room temperature to obtain a conversion solution; The total glycoside content of the steviol glycoside is ≥90%, the glycosyl donor is β-cyclodextrin or maltodextrin; the weight ratio of steviol glycoside to glycosyl donor is 0.5-1:1; the enzyme is cyclodextrin glucosyltransferase, the enzyme addition amount is 1-2% of the weight of steviol glycoside, the reaction temperature is 75-80°C, the reaction time is 24-48h; the stirring speed is 100-200rpm, the pH value is 6-7; the concentration of the reaction system is 20%-30%, the reaction solvent is water; the inactivation temperature is 95°C, and the inactivation time is 20-30min; b. Hydrolysis: adding 0.01% volume of hydrolase to the conversion solution obtained in step a, hydrolyzing for 24 to 32 hours at a temperature of 20 to 25 ° C, a pH value of 6 to 7, and a stirring speed of 20 rpm to obtain a hydrolyzate; the hydrolase is pullulanase and saccharifying enzyme, each of which is added to 0.01% volume of the conversion solution; c. Impurity separation: The hydrolyzate obtained in step b is separated and hydrolyzed by an ultrafiltration membrane; the ultrafiltration membrane is an ultrafiltration membrane with a pore size of 0.02 microns, and water is added when the ultrafiltration clear liquid penetrates to half the volume of the material, the amount of water added is 1 times that of the conversion liquid, and the membrane pressure is 2 to 3Mpa; the membrane retentate is obtained; d. Concentration: The membrane retentate obtained in step c was concentrated by negative pressure evaporation at a temperature of 70°C to 75°C and a pressure of -0.08 to -0.1 MPa to a solid content of 70% to 75%, and then spray-dried to obtain a dry powder; e. Refining: The dry powder obtained in step d is put into an ethanol solution with a volume concentration of 80% to 85%, stirred, and diatomaceous earth is added after stirring evenly, and then filtered after standing; the amount of the ethanol solution added is 7 to 8 times the amount of the dry powder added in step c, and the stirring speed is 100 to 200 rpm; the stirring time is 10 to 60 min; 1% diatomaceous earth by volume of the material obtained after the above dry powder is dissolved is added, and the temperature is 20 to 25 ° C. The conditions are allowed to stand for 20 to 60 min, and the clear liquid is filtered; f. Concentration: The ethanol in the clear solution obtained in step e was dealcoholized by negative pressure evaporation and concentration, the heating temperature was 70 to 75 ° C, the pressure was -0.08 to -0.1 MPa, and the solid content was concentrated to 70 to 75% to obtain a concentrate; g. Drying: spray drying the concentrated solution obtained in step f to obtain the finished glucosyl stevioside; the spray drying air inlet temperature is 175°C to 180°C, and the air outlet temperature is 85°C to 90°C.

2. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: In step a, the glycosyl donor is maltodextrin; the weight ratio of stevioside to dextrin is 1:1; the enzyme addition amount is 1% of the weight of stevioside, the reaction temperature is 80°C, and the reaction time is 24h; the stirring speed is 120rpm, and the pH value is 5.5; the reaction system concentration is 20%, and the reaction solvent is water; the inactivation temperature is 95°C, and the inactivation time is 20min.

3. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: In the step b, hydrolysis is performed for 30 hours at a temperature of 25° C., a pH value of 6.5, and a stirring speed of 20 rpm to obtain a hydrolyzate.

4. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: The transmembrane pressure in step c is 2.5 MPa.

5. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: In the step d, the evaporation temperature is 75° C. and the pressure is -0.1 MPa until the solid content reaches 70%.

6. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: The volume concentration of the ethanol solution in step e is 80%, and the amount of ethanol solution added is 7 times the weight of the dry powder obtained in step c; the stirring speed is 120 rpm; the stirring time is 30 min; the temperature is 25° C., and the standing time is 20 min.

7. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: In the step f, the heating temperature is 75° C., the pressure is -0.1 MPa, and the mixture is concentrated to a solid content of 70%.

8. The method for preparing glucosyl steviol glycoside according to claim 1, characterized in that: In step g, the spray drying air inlet temperature is 180°C and the air outlet temperature is 85°C.

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