CN101717418B - Technology for separating stevioside in one step with simulated moving bed - Google Patents

Abstract

The one-step method of separating stevioside in a simulated moving bed of the present invention involves immersing tiny stevia leaf fragments in water for 0.5 to 1 hour, then introducing ultrasonic waves with a frequency of 50 to 90 khz, performing coarse filtration, extracting the filtrate, and adding KAL(SO ₄ )2 and CaO, adjust the pH value to 7, and let it stand for 0.5-3.0 hours at a temperature of 50-60°C. After removing impurities, perform fine filtration on the filtrate, then concentrate, absorb and separate, and dry. That is, stevioside powder is obtained. In this method, the ultrasonic extraction equipment carries out rapid water extraction of stevioside in stevia leaves, the extractant is non-toxic, the extraction time is shortened, and the extraction rate is improved. Purification and refinement are improved, the amount of regenerant and energy consumption are reduced, the recovery rate is as high as about 90%, and the purity also reaches more than 93%, which can realize continuous production and is easy to industrialize.

Description

One-step separation of stevioside in simulated moving bed

technical field

The invention relates to a technology for one-step separation of stevioside in a simulated moving bed, specifically a method for extracting stevioside leaves with an ultrasonic method, and separating and purifying the stevioside in the crude extract through a simulated moving bed.

Background technique

Stevia rebaudiana is a perennial herbaceous plant belonging to the Asteraceae Stevia family. Its origin is in the subtropical region of South America. It was successfully introduced and cultivated in my country in 1977. Stevia contains 14 kinds of trace elements and 32 kinds of nutrients, so it is not only an excellent source of sugar, but also a good source of nutrition. Stevioside is a mixture of diterpene glycosides containing 8 components extracted from stevia leaves. According to the division of natural phytochemistry, it belongs to the glycosides of tetracyclic diterpene. It has high sweetness, low calorie, Features such as safety and non-toxicity are gradually favored by people. Among the 8 known glycosides of stevioside, the content, taste and sweetness of various components are different, among which Stevioside (St), Rebaudioside A (RA), Rebaudioside C ( RC) content is higher, accounting for more than 90%. RA has the highest sweetness, equivalent to 450 times that of sucrose, and its sweetness is also similar to that of sucrose. It is a new type of natural sweetener with the characteristics of high sweetness, low calorie, easy solubility, heat resistance, and stability. Experiments have proved that stevioside has no toxic side effects, no carcinogenicity, no residue, safe and reliable, regular consumption can prevent hypertension, heart disease, dental caries and other diseases, especially suitable for the health care of diabetics, phenylketonuria patients and obese people . Stevioside is the natural low-calorie sweetener that has been found in the world and is approved by the Ministry of Health and the Ministry of Light Industry of my country. Sucrose substitute, known as "the third sucrose in the world".

Due to the excellent physiological properties and stability of stevioside, as a new type of food additive, it is widely used in food, beverage, brewing, medicine, daily chemical industry and other industries. Not only the extraction process is becoming more and more mature, but the extraction rate is also increasing. At present, the methods for extracting stevioside from stevia leaves mainly include organic solvent extraction and water extraction, among which the organic solvent extraction consumes a lot of solvent, has high cost and is not practical. Hot water extraction is a widely used extraction method at present. The general process of water extraction of stevioside in industry is as follows: stevia leaves→water immersion (8～10h)→coarse filtration→precipitation to remove impurities→fine filtration→purification →Decolorization→Desalination→Concentration and drying, in which water extraction and purification are the key steps of the process. The widely used extraction method is multiple leaching with hot water at 80°C. The purification method is now mostly using resin adsorption separation, decolorization There are two main methods: activated carbon decolorization and resin decolorization. The disadvantages of this process are long extraction time, high heat energy consumption, high temperature and high pressure requirements for equipment operation safety, poor continuity in the purification and decolorization process, large amount of resin and reagents, low resin utilization rate, and long operation time.

Contents of the invention

The present invention is aimed at overcoming the deficiencies of the prior art, and has developed a technology for separating steviosides by using ultrasonic waves combined with a simulated moving bed one-step method, and purifies and decolorizes steviosides through simulated moving bed ion exchange equipment, shortening the The extraction time of glycosides is shortened, the operation steps are simplified, the production loss is reduced, and continuous production is possible, which improves the production efficiency.

The simulated moving bed one-step method separation stevioside technology of the present invention is realized through the following steps:

a, pulverization: the stevia leaves are made into fine fragments;

b. Water immersion: soak the stevia leaf fragments prepared in step a in water for 0.5 to 1 hour, and feed the ingredients in a weight ratio of 1: 15 to 30;

c. Introduce ultrasonic waves: apply ultrasonic waves to the solution in step b, with a frequency of 50-90khz, to rupture the plant cell walls of the material and dissolve the ingredients;

d. Coarse filtration: filter the mixture treated in step c with a filter cloth of 50 to 200 meshes to remove leaf residue;

e. Precipitation: extract the filtrate obtained in step d, add KAL(SO ₄ ) ₂ with a weight percentage of 0.6-1.2% of the leachate and CaO with a weight percentage of 0.6-1.2% of the leachate, adjust the pH to 7, and Under the condition of ~60°C, let stand for 0.5-3.0 hours to remove impurities;

f, fine filtration: filter the solution prepared in step e with a micron filter to obtain a clear orange-yellow liquid;

g, concentrating: the filtrate obtained in step f is concentrated with a rising membrane concentrator to concentrate the rebaudioside extract to contain 8-30% of rebaudioside in every milliliter;

h. Adsorption separation: The rebaudioside semen obtained in the step g is then subjected to continuous separation and purification with a simulated moving bed to obtain a liquid with a mass percentage concentration of 20-45% and a purity of 60-90% rebaudioside;

j. Concentration and drying: Concentrate the stevioside liquid obtained in step h, and spray dry at a temperature of 180-230° C. to obtain stevioside powder.

In the simulated moving bed continuous adsorption separation of the present invention, the adsorbent is any one of macroporous adsorption resin AB-8, ADS-8, D-06, ADS-7 or ADS-17; % ethanol solution, the dosage is 1 to 4 times the volume of the resin; the washing area is deionized water; the resin adsorption regeneration solvent is 2% to 4% NaOH solution; the flow rate in the adsorption area is 5 to 12BV/h; the flow rate in the desorption area is 10 ~25BV/h; the flow rate in the washing area is 8~30BV/h; the flow rate in the regeneration area is 4~10BV/h; the switching time is 650~800s; the temperature is controlled at 30~60°C; the pressure is controlled at 0.2MPa~1.0MPa.

The invention uses a simulated moving bed to carry out continuous desalination, decolorization and adsorption separation, and completes it in one step without additional decolorization and desalination procedures.

The present invention extracts rebaudioside from stevia leaves for the first time by ultrasonic method, adopts simulated moving bed continuous chromatographic separation technology to separate and purify stevioside in one step, and completes purification, desalination and decolorization in one step.

Ultrasonic extraction, also known as ultrasonic-assisted extraction, is to use the multi-level effects such as strong cavitation effect, disturbance effect, high acceleration, crushing and stirring effect produced by ultrasonic radiation pressure to increase the frequency and speed of material molecule motion and increase solvent penetration. Force, so as to accelerate the target components into the solvent, and promote the extraction. Ultrasonic extraction has completely changed the traditional boiling alcohol precipitation extraction method. Compared with the boiling alcohol precipitation process, ultrasonic extraction has the following characteristics: normal temperature and pressure, safe and easy to operate, continuous operation throughout the process, high production efficiency, low energy consumption, and reduced labor Intensity, large processing capacity and low cost; the ultrasonic extraction time is shortened by 7-9 hours compared with the conventional method, the temperature is reduced by 30°C-40°C, and the yield is increased by 5%-30%; the amount of dynamic countercurrent extraction solvent is reduced by 30%-50%. The efficiency is increased by 5% to 20%; the automatic discharge device of medicinal residues: solves the unsafe, troublesome, sealing and other problems in the discharge of medicinal residues; the medicinal residues are squeezed dry, and the liquid content reaches 50%, reducing the waste of raw materials.

Adsorption is an important separation method in chemical engineering, which utilizes the difference in partition coefficient between the mobile phase and the stationary phase for the components to be separated. In the early stage of the development of adsorption technology, fixed bed was mainly used, and it was carried out in a relatively simple intermittent manner such as breakthrough regeneration. This method has a low utilization rate of adsorbent capacity and is difficult to obtain high-purity products. In the moving bed adsorption separation process, the solid adsorbent moves from top to bottom under the action of gravity and contacts with the mobile phase countercurrently, which improves the efficiency of the process, but this operation method has strict requirements on the wear resistance of the adsorbent, and the solid phase Movement increases backmixing, making it difficult for the flow to maintain ideal plug flow. The simulated moving bed technology solves the difficulties encountered in the moving bed technology by periodically changing the inlet and outlet positions of the mobile phase streams to cause the relative countercurrent movement of the stationary phase and the mobile phase, and pushes the adsorption technology to a broad field. development space. The characteristics of the one-step separation of stevioside by simulated moving bed are: using a resin to complete the three-step process of adsorption, elution, desalination and decolorization of the original resin in one step by the separation of simulated moving bed chromatography; the resin has a large amount of pigment adsorption, and the adsorption capacity Strong, more thorough decolorization; high resin utilization rate, 60% reduction in usage, 70% eluent savings; continuous automatic operation, so that product quality is guaranteed, product purity can reach more than 90%, and yield can be increased by 1 to 5 %; the labor intensity is reduced, and the production site is greatly reduced; the operating cost is greatly reduced, only 25% to 40% of other processes; the whole process can achieve no discharge of three wastes, and realizes clean production.

The simulated moving bed one-step method separation stevioside technology of the present invention uses ultrasonic extraction equipment to carry out rapid water extraction of stevioside in stevia leaves, the extractant is non-toxic, the extraction time is shortened, and the extraction rate is improved. The bed ion exchange equipment has purified and refined the stevioside crude extract. Compared with the fixed bed, the amount of resin, the amount of regenerant, and the energy consumption are reduced. Realize continuous production and be easy to industrialize.

Detailed ways

Example 1

The technology for separating stevioside by one-step simulated moving bed method of the present invention is realized through the following steps using stevia leaves as raw materials:

a, pulverization: the stevia leaves are made into fine fragments;

b. Water immersion: soak the stevia leaf fragments prepared in step a in water for 0.5 to 1 hour, and feed the ingredients in a weight ratio of 1: 15 to 30;

c. Introduce ultrasonic waves: apply ultrasonic waves to the solution in step b, with a frequency of 50-90khz, to rupture the plant cell walls of the material and dissolve the ingredients;

d. Coarse filtration: filter the mixture treated in step c with a filter cloth of 50 to 200 meshes to remove leaf residue;

e. Precipitation: extract the filtrate obtained in step d, add KAL(SO ₄ ) ₂ with a weight percentage of 0.6-1.2% of the leach solution and CaO with a weight percentage of 0.6-1.2% of the leach solution, add hydrochloric acid, and adjust the pH value to 7. Under the condition of temperature 50-60℃, let it stand for 0.5-3.0 hours to remove impurities such as protein, organic acid, pigment and tannin;

f, fine filtration: filter the solution prepared in step e with a micron filter to obtain a clear orange-yellow liquid;

g, concentrating: the filtrate obtained in step f is concentrated with a rising membrane concentrator to concentrate the rebaudioside extract to contain 8-30% of rebaudioside in every milliliter;

h. Adsorption separation: The rebaudioside semen obtained in the step g is then subjected to continuous separation and purification with a simulated moving bed to obtain a liquid with a mass percentage concentration of 20-45% and a purity of 60-90% rebaudioside;

j. Concentration and drying: Concentrate the stevioside liquid prepared in step h, and spray dry it at a temperature of 180-230°C to obtain stevioside powder;

Wherein, the adsorbent in the simulated moving bed in step h adopts any one of macroporous adsorption resin AB-8, ADS-8, D-06, ADS-7 or ADS-17; the resolving agent is 50% to 70% ethanol solution, the amount of which is 1 to 4 times the volume of the resin; the washing area is deionized water; the resin adsorption regeneration solvent is 2% to 4% NaOH solution;

Adsorption zone: flow rate 5~12BV/h; washing zone 1: flow rate 8～30BV/h; desorption zone: flow rate 10～25BV/h; regeneration zone: flow rate 4～10BV/h; washing zone 2: flow rate 8～30BV/h h;

Switching time is 650-800s; pressure control is 0.2MPa-1.0MPa.

Example 2

The technology for separating stevioside by one-step simulated moving bed method of the present invention is realized through the following steps using stevia leaves as raw materials:

a, pulverization: the stevia leaves are made into fine fragments;

b, water immersion: take 100 grams of stevia leaf fragments obtained through step a and soak in 1500 grams of water for 0.5 hour;

c. Import ultrasonic waves: apply ultrasonic waves to the solution in step b, with a frequency of 50khz, to rupture the plant cell walls of the material and dissolve the ingredients;

D, coarse filtration: carry out 50 purpose filter cloths to filter the mixture processed through c step, remove leaf residue;

e. Precipitation: extract the filtrate obtained in step d, add 9 grams of KAL(SO ₄ ) ₂ and 9 grams of CaO, add hydrochloric acid, adjust the pH value to 7, and let it stand for 0.5-60°C at a temperature of 50-60°C 3.0 hours, remove protein, organic acid, pigment, tannin and other impurities;

f, fine filtration: filter the solution prepared in step e with a micron filter to obtain a clear orange-yellow liquid;

g, concentrating: the filtrate obtained in step f is concentrated with a rising membrane concentrator to concentrate the rebaudioside extract to contain 8-30% of rebaudioside in every milliliter;

h. Adsorption separation: The rebaudioside semen obtained in the step g is then subjected to continuous separation and purification with a simulated moving bed to obtain a liquid with a mass percentage concentration of 20-45% and a purity of 60-90% rebaudioside;

j. Concentration and drying: Concentrate the stevioside liquid prepared in step h, and spray dry it at a temperature of 180-230°C to obtain stevioside powder;

Among them, the adsorbent in the simulated moving bed in step h is macroporous adsorption resin AB-8; the desorbent is 50%-70% ethanol solution, and its dosage is 1 times the volume of the resin; the washing area is deionized water; the resin is adsorbed and regenerated The solvent is 2% to 4% NaOH solution;

Adsorption area: flow rate 5BV/h; washing area 1: flow rate 8BV/h; desorption area: flow rate 10BV/h; regeneration area: flow rate 4BV/h; washing area 2: flow rate 8BV/h;

Switching time is 650s; pressure control is 0.2MPa.

Example 3

The technology for separating stevioside by one-step simulated moving bed method of the present invention is realized through the following steps using stevia leaves as raw materials:

a, pulverization: the stevia leaves are made into fine fragments;

b, water immersion: take 100 grams of stevia leaf fragments obtained through step a and soak in 3000 grams of water for 1 hour;

c, importing ultrasonic waves: applying ultrasonic waves to the solution in step b, the frequency is 90khz, so that the material plant cell wall is broken, and the ingredients are dissolved;

D, coarse filtration: carry out 200 purpose filter cloths to filter the mixture processed through c step, remove leaf residue;

e. Precipitation: extract the filtrate obtained in step d, add 18 grams of KAL(SO ₄ ) ₂ and 18 grams of CaO, add hydrochloric acid, adjust the pH value to 7, and let it stand for 0.5-60°C at a temperature of 50-60°C 3.0 hours, remove protein, organic acid, pigment, tannin and other impurities;

f, fine filtration: filter the solution prepared in step e with a micron filter to obtain a clear orange-yellow liquid;

g, concentrating: the filtrate obtained in step f is concentrated with a rising membrane concentrator to concentrate the rebaudioside extract to contain 8-30% of rebaudioside in every milliliter;

h. Adsorption separation: The rebaudioside semen obtained in the step g is then subjected to continuous separation and purification with a simulated moving bed to obtain a liquid with a mass percentage concentration of 20-45% and a purity of 60-90% rebaudioside;

j. Concentration and drying: Concentrate the stevioside liquid prepared in step h, and spray dry it at a temperature of 180-230°C to obtain stevioside powder;

Among them, in step h, the adsorbent in the simulated moving bed is macroporous adsorption resin ADS-8; the desorbent is 50% to 70% ethanol solution, and its dosage is 4 times the volume of the resin; the washing area is deionized water; the resin is adsorbed and regenerated The solvent is 2% to 4% NaOH solution;

Adsorption zone: flow rate 12BV/h; Washing zone 1: Flow rate 30BV/h; Desorption zone: Flow rate 25BV/h; Regeneration zone: Flow rate 10BV/h; Washing zone 2: Flow rate 30BV/h;

Switching time is 800s; pressure control is 1.0MPa.

Example 4

Remove the gravel from the dried leaves of Stevia rebaudiana purchased, crush the dried leaves into fine fragments with a grinder, and store them in a dark and dry place. Take 100 grams of stevia leaf fragments and soak them in 2500 grams of water to soak 0.8 Hours later, in the solution, ultrasonic waves are applied, and the ultrasonic frequency is 70khz, so that the plant cell wall of the material is broken, and the ingredients are dissolved; then the stevia residue is removed with 100 mesh filter cloth, and then 25 grams of KAL (SO ₄ ) are added to the filtrate ₂ and Add hydrochloric acid to 25 grams of CaO, adjust the pH value to 7, let it stand until the precipitation is complete, and use a plate and frame filter to completely remove the precipitation to obtain a clear orange-yellow liquid. Then use a 1 μm titanium rod to further filter, and use a rising membrane concentrator to concentrate the obtained filtrate to a semen containing 9% stevioside per milliliter, and use a simulated moving bed or column chromatography for one-step separation and purification of the stevioside semen , that is, a liquid with a mass percentage concentration of 20-45% and a purity of 60-90% stevioside is obtained; and then concentrated and dried to obtain a stevioside powder.

Among them, h step simulates that the adsorbent in the moving bed is macroporous adsorption resin D-06; the resolving agent is 50% to 70% ethanol solution, and its dosage is 3 times the volume of the resin; the washing area is deionized water; the resin is adsorbed and regenerated The solvent is 2% to 4% NaOH solution;

Adsorption area: flow rate 10BV/h; washing area 1: flow rate 25BV/h; desorption area: flow rate 20BV/h; regeneration area: flow rate 8BV/h; washing area 2: flow rate 28BV/h;

Switching time is 750s; pressure control is 0.8MPa.

Example 5

Remove the gravel from the purchased stevia dry leaves, crush the dry leaves into fine pieces with a grinder, and store them in a dark and dry place. Take 100 grams of stevia leaf fragments and soak them in 2000 grams of water for 1 hour , apply ultrasonic waves in the solution, the ultrasonic frequency is 60khz, filter with 100 mesh filter cloth again, remove stevia rebaudiana residue, then add 16 grams of KAL(SO ₄ ) ₂ and the CaO of 20 grams in the filtrate, add hydrochloric acid, adjust When the pH value reaches 7, stand for 2 hours at a temperature of 50°C to remove solid impurities; then use a plate and frame filter to completely remove the precipitate to obtain a clear orange-yellow liquid. Then use a titanium rod to further filter, and use a rising membrane concentrator to concentrate the obtained filtrate to a semen containing 9% stevioside per milliliter, and use a simulated moving bed to carry out one-step continuous separation and purification of the stevioside semen to obtain quality A liquid with a percentage concentration of 20-45% and a purity of 60-90% stevioside; then concentrated and dried to obtain stevioside powder;

Among them, the adsorbent in the simulated moving bed in the step h is macroporous adsorption resin ADS-7; the desorbent is 50% to 70% ethanol solution, and its dosage is twice the volume of the resin; the washing area is deionized water; the resin is adsorbed and regenerated The solvent is 2% to 4% NaOH solution;

Adsorption zone: flow rate 8BV/h; washing zone 1: flow rate 15BV/h; desorption zone: flow rate 15BV/h; regeneration zone: flow rate 6BV/h; washing zone 2: flow rate 15BV/h.

Switching time is 700s; pressure control is 0.6MPa.

The core technology of the present invention is the application of the simulated moving technique in the separation and extraction of stevioside. In addition to the function of the traditional simulated moving bed, it also has the following characteristics: the partition mode, the number of preparation columns in each area, and the connection of preparation columns can be designed by themselves. There are multiple feed ports and discharge ports, which can be changed completely according to the needs of the process.

The process flow of the simulated moving bed described in Examples 1-5: adsorption→water washing→desorption→regeneration→water washing.

Claims (3)

1. The method for separating stevioside by one-step method of simulated moving bed is realized by following steps as raw material with stevia leaves: a, pulverization: the stevia leaves are made into fine fragments; b. Water immersion: soak the stevia leaf fragments prepared in step a in water for 0.5-1 hour, and the weight ratio of feeding is 1:15-30; c. Introduce ultrasonic waves: apply ultrasonic waves to the solution in step b, with a frequency of 50-90khz, causing the cell walls of the material plants to rupture and the ingredients to dissolve; d. Coarse filtration: filter the mixture treated in step c with a filter cloth of 50 to 200 meshes to remove leaf residue; e. Precipitation: extract the filtrate obtained in step d, add KAL(SO ₄ ) ₂ with a weight percentage of 0.6-1.2% of the leaching liquid and CaO with a weight percentage of 0.6-1.2% of the leaching liquid, adjust the pH value to 7, and set the pH value at 50 Under the condition of ~60°C, let stand for 0.5-3.0 hours to remove impurities; f, fine filtration: filter the solution prepared in step e with a micron filter to obtain a clear orange-yellow liquid; g, concentrating: the filtrate obtained in step f is concentrated with a rising membrane concentrator to concentrate the rebaudioside extract to contain 8-30% rebaudioside in every milliliter; h. Adsorption separation: The rebaudioside semen obtained in step g is then subjected to continuous separation and purification with a simulated moving bed, that is, a liquid with a mass percentage concentration of 20-45% and a purity of 60-90% rebaudioside is obtained; j. Concentration and drying: Concentrate the stevioside liquid obtained in step h, and spray dry at a temperature of 180-230° C. to obtain stevioside powder. 2. the method for the one-step separation of stevioside by simulated moving bed as claimed in claim 1, is characterized in that in the h step, in the continuous adsorption separation of simulated moving bed, the adsorbent is a macroporous adsorption resin; the resolving agent is 50%～70% % ethanol solution, the dosage is 1 to 4 times the volume of the resin; the washing area is deionized water; the resin adsorption regeneration solvent is 2% to 4% NaOH solution; the flow rate in the adsorption area is 5 to 12BV/h; the flow rate in the desorption area is 10 ~25BV/h; the flow rate in the washing area is 8~30BV/h; the flow rate in the regeneration area is 4~10BV/h; the switching time is 650~800s; the temperature is controlled at 30~60°C; the pressure is controlled at 0.2MPa~1.0MPa. 3. the method for the one-step separation of stevioside by simulated moving bed as claimed in claim 2, is characterized in that the macroporous adsorption resin is AB-8, ADS-8, D-06, ADS-7 or ADS-17 any type.