Process method for removing pre-impurities and decolorizing RM mother liquor sugar in stevioside production

Abstract

The invention relates to the technical field of stevioside, in particular to a pre-impurity-removing and decolorizing process method for RM mother liquor sugar in stevioside production, which comprises the following steps: taking the RM mother liquor sugar as a raw material, adding water-saturated ethyl acetate into a sugar solution added with an aqueous solution, and treating, so that impurities such as polyphenol and flavone in the sugar solution can be effectively removed; drying the layered and collected water phase layer, enabling the obtained solid powder dissolved feed liquid to enter a medium-low pressure chromatographic column, treating by adopting a first eluent, and then treating by adopting a second eluent, so as to obtain a second eluent; the collected second eluent sequentially enters a first anion resin column, a first cation resin column, a second anion resin column and a second cation resin column which are connected in series, effluent containing glucoside is collected and treated through ozone strong oxidation decolorization equipment, and obtained decolorized glucoside feed liquid is subjected to spray drying. According to the process method, the RM mother liquor sugar is effectively treated, the total glycoside content and the product value are greatly improved, and economic benefits are increased for enterprises.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steviol, in particular to a process method for removing impurities and decolorizing RM mother liquor sugar in the production of steviol. BACKGROUND

[0002] RM mother liquor sugar (in the production process of steviol, the components with relatively high RM content are separated from the system, RM is produced by crystallization, and the mother liquor remaining after RM crystallization is dried to obtain RM mother liquor sugar) as a byproduct, its color is poor (usually dark brown or dark yellow), the taste is bitter, and the total glycoside content is low (usually between 30-50%), due to low market acceptance, it is often used as low-value feed or abandoned.

[0003] The prior art mainly improves the color by simple filtration or activated carbon decolorization, but these methods cannot effectively remove impurities (such as gum, pigment, organic acid, etc.); in addition, the conventional decolorization process may introduce odor or secondary pollution, further reducing the product quality. The residual impurities not only inhibit the decolorization effect, but also affect the purity and stability of the total glycoside, resulting in limited color improvement, poor taste, and difficulty in improving the total glycoside content. These problems make it impossible to efficiently upgrade the stock mother liquor sugar to high-value-added products, resulting in resource waste and economic loss. Therefore, in view of the above problems, it is necessary to develop a process method for removing impurities and decolorizing steviol mother liquor sugar. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a process method for removing impurities and decolorizing RM mother liquor sugar in the production of steviol, which improves the total glycoside content of the mother liquor sugar, improves the color and taste, and increases the economic benefits of enterprises.

[0005] To solve the above technical problems, the technical scheme of the present application is:

[0006] A process method for removing impurities and decolorizing RM mother liquor sugar in the production of steviol, comprising the following process steps:

[0007] (1) Take RM mother liquor sugar, add water-saturated ethyl acetate to the mother liquor solution after dissolving, stir and mix, and stand for separation, then collect the water phase layer and dry to obtain solid material for standby use;

[0008] (2) Take the solid material in step (1), dissolve in water, and then pass the solution into a medium-low pressure chromatographic column, add water to top up after the sample is added, then use a first eluent for elution treatment, and discard the collected first eluent; then use a second eluent for elution treatment, and collect the second eluent for standby use;

[0009] (3) Take the second eluent from step (2) and enter the first anion exchange resin column, the first cation exchange resin column, the second anion exchange resin column and the second cation exchange resin column connected in series. Start collecting when glycosides are discharged in the effluent and collect the effluent containing glycosides for later use.

[0010] (4) Take the effluent containing glycosides from step (3), treat it with ozone strong oxidation decolorization equipment, and the decolorized glycoside liquid can be spray dried.

[0011] As an improved technical solution, the total glycoside content of the RM mother liquor sugar in step (1) is 40%-49.1%, and the RM mother liquor sugar contains RA 22.7-28%, RO 0.1-5%, RD 1-7%, RN 0.5-5%, RM 0.1-4%, STV 2-5%, RC 0.2-2.5%, RB 0.1-3.3%, and the total content of tetraglycosides of RF, DA, RU, and disaccharides is 1-4%.

[0012] As an improved technical solution, the solid content of the mother liquor sugar solution in step (1) is 20-50% (w / w), and the mother liquor sugar solution is mixed with the water-saturated ethyl acetate in a volume ratio of 1:1-10.

[0013] As an improved technical solution, the solid content of the feed solution in step (2) is 10-30% (w / w), and the feed solution enters the medium-low pressure chromatographic column at a flow rate of 0.5-3 BV / h.

[0014] As an improved technical solution, the interior of the medium-low pressure chromatographic column in step (2) is filled with reversed-phase silica gel packing material, and the surface area of ​​the reversed-phase silica gel packing material is 350 m². 2 / g, pore size is 120 Å, particle size is 30 μm.

[0015] As an improved technical solution, in step (2), the flow rates of the first eluent and the second eluent are both 1-3 BV / h, the first eluent is ethanol with a volume concentration of 20-40%, and the second eluent is ethanol with a volume concentration of 75-85%.

[0016] As an improved technical solution, in step (3), the second effluent enters the first anion exchange resin column, the first cation exchange resin column, the second anion exchange resin column, and the second cation exchange resin column sequentially at a flow rate of 0.3-0.5 BV / h per column volume.

[0017] As an improved technical solution, in step (3), the fillers in the first anion exchange resin column and the second anion exchange resin column are both weakly basic anion exchange resins, specifically model T8; the fillers in the first cation exchange resin column and the second cation exchange resin column are both strongly acidic cation exchange resins, specifically model D331.

[0018] As an improved technical solution, in step (4), the effluent containing glycosides is heated to 15-35℃ and enters the ozone strong oxidation decolorization equipment at a flow rate of 1.5-6 BV / h, wherein the ozone concentration of the ozone strong oxidation decolorization equipment is 20-100ppm.

[0019] After adopting the above technical solution, the beneficial effects of the present invention are:

[0020] This invention uses RM mother liquor sugar as raw material. The sugar solution, after being treated with an aqueous solution, is treated with water-saturated ethyl acetate, which effectively removes impurities such as polyphenols and flavonoids. The collected aqueous phase is dried, and the resulting solid powder is dissolved and fed into a medium-low pressure chromatographic column. The solution is treated with a first eluent, followed by a second eluent. The collected second eluent is then sequentially fed into a series of columns: a first anion exchange resin column, a first cation exchange resin column, a second anion exchange resin column, and a second cation exchange resin column. The eluent containing glycosides is collected and treated with an ozone strong oxidation decolorization device. The decolorized glycoside solution is then spray-dried. This process effectively treats RM mother liquor sugar, significantly increasing the total glycoside content, enhancing product value, and increasing economic benefits for enterprises. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1

[0023] A method for removing impurities and decolorizing RM mother liquor sugar in stevia production includes the following process steps:

[0024] (1) Take 100g of RM mother liquor sugar (total glycoside content 40%, RA 28%, RO 0.1%, RD 1%, RN 0.5%, RM 0.1%, STV 2%, RC 1%, RB 3.3%, RF 1%, DA 1%, RU 1%, disaccharide 1%), dissolve it in water to obtain 460mL of mother liquor sugar solution with a solid content of 20% (w / w), add water-saturated ethyl acetate at a volume ratio of 1:1, stir (stirring speed 120 rpm) to mix, let stand for 1h to separate the layers, collect the aqueous phase layer and dry it to obtain 64g of solid for later use;

[0025] (2) Take 64g of the solid from step (1), dissolve it in water to obtain 614.4mL of a feed solution with a solid content of 10% (w / w), and inject it into a 1.3L medium-low pressure chromatographic column (with reversed-phase silica gel packing material and a surface area of ​​350m²) at a flow rate of 0.5 BV / h. 2 / g, pore size 120A, particle size 30um), after the sample is injected, 600mL of water is added to top the sample, and then 5L of the first eluent (20% ethanol) is used for elution at a flow rate of 1BV / h. The collected first eluent is discarded; then 3L of the second eluent (75% ethanol) is used for elution at a flow rate of 1BV / h, and 3L of the second eluent is collected for later use.

[0026] (3) Take 3L of the second eluent from step (2) and enter it into a series of 150mL first anion exchange resin column (weakly basic anion exchange resin, specifically model T8), 150mL first cation exchange resin column (strongly acidic cation exchange resin, specifically model D331), 150mL second anion exchange resin column (weakly basic anion exchange resin, specifically model T8) and 150mL second cation exchange resin column (strongly acidic cation exchange resin, specifically model D331) at a flow rate of 0.3BV / h per column. Start collecting when glycosides are discharged in the eluent and collect 3.2L of the eluent containing glycosides for later use.

[0027] (4) Take 3.2L of the effluent containing glycosides from step (3), control the temperature to 15℃, and enter the ozone strong oxidation decolorization equipment at a flow rate of 1.5BV / h (ozone concentration is 20ppm, equipment purchased from the manufacturer). After decolorization, the glycoside solution is spray-dried to obtain a white glycoside product with a yield of 42g, a total glycoside content of 65%, RA 44.1%, RO 0.1%, RD 1.2%, RN 0.5%, RM 0.1%, STV 5%, RC 1.8%, RB 5.5%, RF 1.6%, DA 1.8%, RU 2%, and disaccharides 1.3%.

[0028] Example 2

[0029] A process for removing impurities and decolorizing RM mother liquor sugar in stevia production includes the following steps:

[0030] (1) Take 100g of RM mother liquor sugar (total glycoside content 42%, RA 23%, RO 1%, RD 1%, RN 1.7%, RM 4%, STV 5%, RC 2.5%, RB 2.5%, RF 0.1%, DA 0.1%, RU 0.1%, disaccharide 1%), dissolve in water to obtain 293.4mL of mother liquor sugar solution with a solid content of 30% (w / w), add water-saturated ethyl acetate at a volume ratio of 1:3, stir (stirring speed 100 rpm) to mix, let stand for 1.5h and separate into layers, collect the aqueous phase layer and dry it to obtain 66.23g of solid for later use;

[0031] (2) Take 66.23 g of the solid from step (1), dissolve it in water to obtain 415 mL of a feed solution with a solid content of 15% (w / w), and inject it into a 1.3 L medium-low pressure chromatographic column (with reversed-phase silica gel packing material and a surface area of ​​350 m²) at a flow rate of 1 BV / h. 2 / g, pore size 120A, particle size 30um), after injection, add 600mL of water to top the sample, then use 12L of the first eluent (25% ethanol) at a flow rate of 1.5BV / h to elute, and discard the collected first eluent; then use 3.9L of the second eluent (78% ethanol) at a flow rate of 1.5BV / h to elute, and collect 3.9L of the second eluent for later use;

[0032] (3) Take 3.9L of the second eluent from step (2) and enter it into a series of 150mL first anion exchange resin column (weak basic anion exchange resin, specifically model T8), 150mL first cation exchange resin column (strong acid cation exchange resin, specifically model D331), 150mL second anion exchange resin column (weak basic anion exchange resin, specifically model T8) and 150mL second cation exchange resin column (strong acid cation exchange resin, specifically model D331) at a flow rate of 0.35BV / h per column. Start collecting when glycosides are discharged in the eluent and collect 4L of the eluent containing glycosides for later use.

[0033] (4) Take 4L of the effluent containing glycosides from step (3), control the temperature to 20℃, and enter the ozone strong oxidation decolorization equipment at a flow rate of 2.5BV / h (ozone concentration of 40ppm, equipment purchased from the manufacturer). After decolorization, the glycoside solution is spray-dried to obtain a white glycoside product with a yield of 44g, a total glycoside content of 67%, RA 41%, RO 1%, RD 1%, RN 1.7%, RM 7%, STV 7%, RC 3.5%, RB 3.5%, RF 0.1%, DA 0.1%, RU 0.1%, and disaccharide 1%.

[0034] Example 3

[0035] A process for removing impurities and decolorizing RM mother liquor sugar in stevia production includes the following steps:

[0036] (1) Take 100g of RM mother liquor sugar (total glycoside content 49.1%, RA 27%, RO 5%, RD 5%, RN 4.5%, RM 2%, STV 2.1%, RC 1%, RB 1%, RF 0.2%, DA 0.6%, RU 0.3%, disaccharide 0.4%), dissolve it in water to obtain 293.4mL of mother liquor sugar solution with a solid content of 30% (w / w), add water-saturated ethyl acetate at a volume ratio of 1:6, stir (stirring speed 120 rpm) to mix, let stand for 1.5h and separate into layers, collect the aqueous phase layer and dry it to obtain 79.1g of solid for later use;

[0037] (2) Take 79.1 g of the solid from step (1), dissolve it in water to obtain 363.86 mL of a feed solution with a solid content of 20% (w / w), and inject it into a 1.3 L medium-low pressure chromatographic column (with reversed-phase silica gel packing material and a surface area of ​​350 m²) at a flow rate of 1.5 BV / h. 2 / g, pore size 120A, particle size 30um), after injection, add 600mL of water to top the sample, then use 4L of the first eluent (30% ethanol) at a flow rate of 2.5 BV / h for elution, and discard the collected first eluent; then use 1.5L of the second eluent (80% ethanol) at a flow rate of 2.5 BV / h for elution, and collect 1.5L of the second eluent for later use;

[0038] (3) Take 1.5L of the second eluent from step (2) and enter it into a series of 150mL first anion exchange resin column (weakly basic anion exchange resin, specifically model T8), 150mL first cation exchange resin column (strongly acidic cation exchange resin, specifically model D331), 150mL second anion exchange resin column (weakly basic anion exchange resin, specifically model T8) and 150mL second cation exchange resin column (strongly acidic cation exchange resin, specifically model D331) at a flow rate of 0.4BV / h per column. Start collecting when glycosides are discharged in the effluent and collect 2L of the effluent containing glycosides for later use.

[0039] (4) Take 2L of the effluent containing glycosides from step (3), control the temperature to 25℃, and enter the ozone strong oxidation decolorization equipment at a flow rate of 3.5BV / h (ozone concentration is 60ppm, equipment purchased from the manufacturer). After decolorization, the glycoside solution is spray-dried to obtain a white glycoside product with a yield of 56.36g, a total glycoside content of 80%, RA 44.3%, RO 8.5%, RD 8%, RN 7.5%, RM 3%, STV 3.1%, RC 1.8%, RB 1.8%, RF 0.3%, DA 0.8%, RU 0.4%, and disaccharides 0.5%.

[0040] Example 4

[0041] A process for removing impurities and decolorizing RM mother liquor sugar in stevia production includes the following steps:

[0042] (1) Take 100g of RM mother liquor sugar (total glycoside content 48%, RA 24%, RO 5%, RD 7%, RN 3.5%, RM 2%, STV 3%, RC 1%, RB 1%, RF 0.1%, DA 0.6%, RU 0.5%, disaccharide 0.3%), dissolve it in water to obtain 192L of mother liquor sugar solution with a solid content of 43% (w / w), add water-saturated ethyl acetate at a volume ratio of 1:8, stir (stirring speed 80 rpm) to mix, let stand for 1h to separate the layers, collect the aqueous phase layer and dry it to obtain 66.2g of solid for later use;

[0043] (2) Take 66.2 g of the solid from step (1), dissolve it in water to obtain 238.32 mL of a feed solution with a solid content of 25% (w / w), and inject it into a 1.3 L medium-low pressure chromatographic column (with reversed-phase silica gel packing material and a surface area of ​​350 m²) at a flow rate of 2.3 BV / h. 2 / g, pore size 120A, particle size 30um), after injection, add 600mL of water to top the sample, then use 6L of the first eluent (35% ethanol) at a flow rate of 2.5 BV / h for elution, and discard the collected first eluent; then use 2.4L of the second eluent (82% ethanol) at a flow rate of 2.5 BV / h for elution, and collect 2.4L of the second eluent for later use;

[0044] (3) Take 2.4L of the second eluent from step (2) and enter it into a series of 150mL first anion exchange resin column (weak basic anion exchange resin, specifically model T8), 150mL first cation exchange resin column (strong acid cation exchange resin, specifically model D331), 150mL second anion exchange resin column (weak basic anion exchange resin, specifically model T8) and 150mL second cation exchange resin column (strong acid cation exchange resin, specifically model D331) at a flow rate of 0.45BV / h per column. Start collecting when glycosides are discharged in the eluent and collect 2.6L of the eluent containing glycosides for later use.

[0045] (4) Take 2.6L of the effluent containing glycosides from step (3), control the temperature to 30℃, and enter the ozone strong oxidation decolorization equipment at a flow rate of 4.5BV / h (ozone concentration is 80ppm, equipment purchased from the manufacturer). After decolorization, the glycoside solution is spray-dried to obtain a white glycoside product with a yield of 48g, a total glycoside content of 64%, RA 33%, RO 8%, RD 9%, RN 4.5%, RM 2.5%, STV 3.5%, RC 1.1%, RB 0.9%, RF 0.1%, DA 0.5%, RU 0.6%, and disaccharides 0.3%.

[0046] Example 5

[0047] A process for removing impurities and decolorizing RM mother liquor sugar in stevia production includes the following steps:

[0048] (1) Take 100g of RM mother liquor sugar (total glycoside content 45%, RA 22.7%, RO 4.5%, RD 4%, RN 4%, RM 3%, STV 4%, RC 0.2%, RB 0.1%, RF 2%, DA 0.1%, RU 0.2%, disaccharide 0.2%), dissolve it in water to obtain 160mL of mother liquor sugar solution with a solid content of 50% (w / w), add water-saturated ethyl acetate at a volume ratio of 1:10, stir (stirring speed 60 rpm) to mix, let stand for 1.1h and separate into layers, collect the aqueous phase layer and dry it to obtain 65.5g of solid for later use;

[0049] (2) Take 65.5 g of the solid from step (1), dissolve it in water to obtain 192.13 mL of a feed solution with a solid content of 30% (w / w), and inject it into a 1.3 L medium-low pressure chromatographic column (with reversed-phase silica gel packing material and a surface area of ​​350 m²) at a flow rate of 3 BV / h. 2 / g, pore size 120A, particle size 30um), after injection, add 600mL of water to top the sample, then use 2.5L of the first eluent (40% ethanol) at a flow rate of 3BV / h to elute, and discard the collected first eluent; then use 1.5L of the second eluent (85% ethanol) at a flow rate of 3BV / h to elute, and collect 1.5L of the second eluent for later use;

[0050] (3) Take 1.5L of the second eluent from step (2) and enter it into a series of 150mL first anion exchange resin column (weakly basic anion exchange resin, specifically model T8), 150mL first cation exchange resin column (strongly acidic cation exchange resin, specifically model D331), 150mL second anion exchange resin column (weakly basic anion exchange resin, specifically model T8) and 150mL second cation exchange resin column (strongly acidic cation exchange resin, specifically model D331) at a flow rate of 0.5BV / h per column. Start collecting when glycosides are discharged in the eluent and collect 1.8L of the eluent containing glycosides for later use.

[0051] (4) Take 1.8L of the effluent containing glycosides from step (3), control the temperature to 35℃, and enter the ozone strong oxidation decolorization equipment at a flow rate of 6BV / h (ozone concentration is 100ppm, equipment purchased from the manufacturer). After decolorization, the glycoside solution is spray-dried to obtain a white glycoside product with a yield of 44.34g, a total glycoside content of 65%, RA 32.4%, RO 6.5%, RD 5.8%, RN 6.3%, RM 4.3%, STV 6.5%, RC 0.3%, RB 0.1%, RF 2.2%, DA 0.1%, RU 0.3%, and disaccharides 0.2%.

[0052] To better demonstrate that the process method of the present invention can increase the total glycoside content of RM mother liquor, the following comparative example is given with reference to Example 3.

[0053] Comparative Example 1

[0054] Unlike Example 3, the mother liquor sugar solution in step (1) was not treated with water-saturated ethyl acetate; the remaining operations were the same. Step (4) yielded a yellow glycoside product with a yield of 43g, a total glycoside content of 49%, RA 32%, RO 0.1%, RD 1%, RN 0.5%, RM 0.1%, STV 5%, RC 1%, RB 5.3%, RF 1%, DA 1%, RU 1%, and a disaccharide content of 1%.

[0055] Comparative Example 2

[0056] Unlike Example 3, the medium-low pressure chromatographic column packing in step (2) was Agilent Poroshell 120EC-C18, and the rest of the operation was the same. Step (4) yielded a white glycoside product with a yield of 49.8g, a total glycoside content of 52%, RA 32.5%, RO 1%, RD 1%, RN 1.7%, RM 4%, STV 5%, RC 3%, RB 2.5%, RF 0.1%, DA 0.1%, RU 0.1%, and disaccharides 1%.

[0057] Comparative Example 3

[0058] Unlike Example 3, the first eluent in step (2) was 18% ethanol by volume, and the rest of the operation was the same. Step (4) yielded a milky white glycoside product with a yield of 59g, a total glycoside content of 55%, RA 34%, RO 5%, RD 5%, RN 4%, RM 2%, STV 2%, RC 1%, RB 1%, RF 0.2%, DA 0.2%, RU 0.2%, and disaccharides 0.4%.

[0059] Comparative Example 4

[0060] Unlike Example 3, the first eluent in step (2) was ethanol with a volume concentration of 45%, and the rest of the operation was the same. Step (4) yielded a white glycoside product with a yield of 25g, a total glycoside content of 35%, RA 25%, RO 1%, RD 1%, RN 1%, RM 2%, STV 2%, RC 1%, RB 1%, RF 0.2%, DA 0.2%, RU 0.2%, and disaccharides 0.4%.

[0061] Comparative Example 5

[0062] Unlike Example 3, the second eluent in step (2) was 70% ethanol by volume, while the rest of the operation was the same. Step (4) yielded 50g of a white glycoside product with a total glycoside content of 68.8%, RA 40%, RO 7%, RD 8%, RN 7%, RM 3%, STV 3%, RC 0.8%, RB 0%, RF 0%, DA 0%, RU 0%, and disaccharides 0%.

[0063] Comparative Example 6

[0064] Unlike Example 3, the filler in the first and second anion exchange resin columns in step (3) is Zhengguang No. 2 resin, while the rest of the operation is the same. Step (4) yields a yellow glycoside product of 50g with a total glycoside content of 74.8%, RA 41.6%, RO 7%, RD 8%, RN 7.2%, RM 3%, STV 3%, RC 1.8%, RB 1.8%, RF 0.3%, DA 0.3%, RU 0.3%, and disaccharides 0.5%.

[0065] Comparative Example 7

[0066] Unlike Example 3, the packing material in the first and second cation exchange resin columns in step (3) was Zhengguang D100FD, and the rest of the operation was the same. Step (4) yielded a yellow glycoside product with a yield of 49g, a total glycoside content of 73%, RA 40.8%, RO 6.5%, RD 7.5%, RN 7.1%, RM 2.8%, STV 3.1%, RC 1.8%, RB 1.8%, RF 0.3%, DA 0.5%, RU 0.4%, and disaccharides 0.4%.

[0067] Comparative Example 8

[0068] Unlike Example 3, the effluent in step (3) was not treated with an ozone strong oxidation decolorization device; the remaining operations were the same. Step (4) yielded a pale yellow glycoside product of 55g, with a total glycoside content of 74.39%, RA 41.8%, RO 6.8%, RD 8.2%, RN 7.2%, RM 2.8%, STV 3%, RC 1%, RB 1.8%, RF 0.3%, DA 0.69%, RU 0.4%, and disaccharides 0.4%.

[0069] Comparative Example 9

[0070] Unlike Example 3, the temperature of the effluent in step (4) was controlled at 12°C, while the rest of the operation was the same. Step (4) yielded a yellowish-brown glycoside product of 51g, with a total glycoside content of 75.4%, RA 42.4%, RO 8.2%, RD 7.3%, RN 7.5%, RM 2.8%, STV 2.6%, RC 1.3%, RB 1.8%, RF 0.2%, DA 0.7%, RU 0.3%, and disaccharides 0.3%.

[0071] Comparative Example 10

[0072] Unlike Example 3, the temperature of the effluent in step (4) was controlled at 38°C, while the rest of the operation was the same. Step (4) yielded a pale yellow glycoside product of 54g, with a total glycoside content of 76.9%, RA 44.3%, RO 7.2%, RD 8%, RN 7.5%, RM 3%, STV 2%, RC 1.8%, RB 1.2%, RF 0.3%, DA 0.8%, RU 0.3%, and disaccharides 0.5%.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for removing impurities and decolorizing RM mother liquor sugar in stevia production, characterized in that, The process includes the following steps: (1) Take the RM mother liquor sugar, add water to dissolve the mother liquor sugar solution, add water-saturated ethyl acetate, stir and mix, let stand to separate the layers, collect the aqueous phase layer and dry it to obtain the solid for later use. (2) Take the solid material described in step (1), add water to dissolve the material solution and enter the medium-low pressure chromatographic column. After the injection is completed, add water to top the material, and then use the first eluent for elution. Discard the collected first eluent. Then use the second eluent for elution and collect the second eluent for later use. (3) Take the second eluent from step (2) and enter the first anion exchange resin column, the first cation exchange resin column, the second anion exchange resin column and the second cation exchange resin column connected in series. Start collecting when glycosides are discharged in the effluent and collect the effluent containing glycosides for later use. (4) Take the effluent containing glycosides from step (3), treat it with ozone strong oxidation decolorization equipment, and the decolorized glycoside liquid can be spray dried.

2. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, The total glycoside content of the RM mother liquor sugar in step (1) is 40%-49.1%, and the RM mother liquor sugar contains RA 22.7-28%, RO 0.1-5%, RD 1-7%, RN 0.5-5%, RM 0.1-4%, STV 2-5%, RC 0.2-2.5%, RB 0.1-3.3%, and the total content of tetraglycosides of RF, DA, RU, and disaccharides is 1-4%.

3. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, The solid content of the mother liquor sugar solution in step (1) is 20-50% (w / w), and the mother liquor sugar solution is mixed with the water-saturated ethyl acetate in a volume ratio of 1:1-10.

4. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, The solid content of the feed solution in step (2) is 10-30% (w / w), and the feed solution enters the medium-low pressure chromatographic column at a flow rate of 0.5-3 BV / h.

5. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, The medium-low pressure chromatographic column mentioned in step (2) is filled with reversed-phase silica gel, and the surface area of ​​the reversed-phase silica gel is 350 m². 2 / g, pore size is 120 Å, particle size is 30 μm.

6. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, In step (2), the flow rates of the first eluent and the second eluent are both 1-3 BV / h. The first eluent is ethanol with a volume concentration of 20-40% and the second eluent is ethanol with a volume concentration of 75-85%.

7. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, In step (3), the second effluent enters the first anion exchange resin column, the first cation exchange resin column, the second anion exchange resin column, and the second cation exchange resin column sequentially at a flow rate of 0.3-0.5 BV / h per column volume.

8. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, In step (3), the fillers in the first anion exchange resin column and the second anion exchange resin column are both weakly basic anion exchange resins, specifically model T8; the fillers in the first cation exchange resin column and the second cation exchange resin column are both strongly acidic cation exchange resins, specifically model D331.

9. The method for removing impurities and decolorizing RM mother liquor sugar in stevia production according to claim 1, characterized in that, In step (4), the effluent containing glycosides is heated to 15-35℃ and enters the ozone strong oxidation decolorization equipment at a flow rate of 1.5-6 BV / h, wherein the ozone concentration of the ozone strong oxidation decolorization equipment is 20-100ppm.