Method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid substances from stevia rebaudiana

Abstract

The invention discloses a method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid substances from stevia rebaudiana. The method comprises the following steps: concentrating stevia rebaudiana extract liquid to obtain permeate liquid I and trapped liquid I; adjusting the pH of the trapped fluid I to obtain a to-be-treated fluid; treating the liquid to be treated by adopting an electrodialysis-ultrafiltration coupling device, and collecting an ion phase I, an ion phase II and a desalted phase; adsorbing the ion phase II by adopting macroporous adsorption resin, and respectively analyzing by adopting a low-alcohol solution and a high-alcohol solution to obtain a low-alcohol analysis solution and a high-alcohol analysis solution; concentrating the high-alcohol desorption solution to obtain trapped fluid II, mixing and crystallizing the trapped fluid II and chlorogenic acid seed crystals, filtering to obtain filtrate I and a filter cake I, refining the filter cake I to obtain filtrate II and a filter cake II, and drying the filter cake II to obtain high-purity chlorogenic acid; concentrating the ion phase I to obtain trapped fluid III, and performing thermal concentration and spray drying on the trapped fluid III to obtain the chlorogenic acid substances. According to the method, the stevia rebaudiana is used as a raw material, high-content chlorogenic acid and chlorogenic acid substances are obtained, less waste liquid and waste materials are generated in the whole process, and the method is more environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of chlorogenic acid preparation, and in particular to a method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia. Background Art

[0002] Chlorogenic acid, also known as 3-caffeoylquinic acid, is an important biologically active substance with antibacterial, antiviral, white blood cell increasing, liver protecting and choleretic, anti-tumor, blood pressure lowering, blood lipid lowering, free radical scavenging and central nervous system stimulating effects.

[0003] At present, the production method of chlorogenic acid is mainly to extract it from plants. The leaves of Stevia not only contain a certain amount of steviol glycosides, but also contain chlorogenic acid substances. Therefore, how to extract chlorogenic acid from Stevia is of certain significance. The main chlorogenic acid substances are as follows: chlorogenic acid (3-caffeoylquinic acid), cryptochlorogenic acid (4-caffeoylquinic acid), neochlorogenic acid (5-caffeoylquinic acid), isochlorogenic acid A (3,5-dicaffeoylquinic acid), isochlorogenic acid B (3,4-dicaffeoylquinic acid), isochlorogenic acid C (4,5-dicaffeoylquinic acid), and cynaroyl (1,3-dicaffeoylquinic acid). Patent application number 201210421968.2 provides a process for preparing stevioside and chlorogenic acid from stevia, which comprises soaking stevia leaves in cold water to extract, adjusting the pH value of the extract after adding divalent iron salt to flocculate, filtering the flocculated liquid to obtain filtrate and filter cake, adsorbing, analyzing and refining the filtrate with macroporous adsorption resin to obtain stevioside, dissolving the filter cake with water and adjusting the pH value to 0.5-5.5 with acid, filtering to obtain chlorogenic acid filtrate, adsorbing the chlorogenic acid filtrate with macroporous adsorption resin, analyzing, concentrating and drying, and recrystallizing to obtain chlorogenic acid. A large amount of solid waste will be generated in the above extraction process, causing environmental pollution; and the product will be damaged to a certain extent during the flocculation process. The patent with application number 202410639319.2 provides a method for extracting chlorogenic acid from stevia, which belongs to the field of plant extraction technology. First, weigh the stevia leaves, add a certain volume of water to soak, filter, take the treated soaking liquid, add lignin and polyaluminum chloride for flocculation reaction, and obtain the upper column liquid; select ion exchange resin for preliminary extraction, analyze the mixed liquid by rotary evaporation, add water, and naturally settle; then purify with macroporous adsorption resin, and dry the analyzed product to obtain a high-content total chlorogenic acid product. Although the total chlorogenic acid in stevia can be recovered in the above process, the obtained product is a chlorogenic acid substance, and the purity of chlorogenic acid is low. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the deficiencies in the prior art, a method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia is provided, wherein the method effectively extracts chlorogenic acid and chlorogenic acid-like substances from stevia, thereby obtaining high-content chlorogenic acid and chlorogenic acid-like substances, and less waste liquid and waste material are generated in the whole process, which is more environmentally friendly.

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

[0006] A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, comprising the following steps:

[0007] (1) crushing dried stevia leaves to obtain stevia powder;

[0008] (2) using ethanol solution as a raw material, repeatedly extracting the stevia powder for multiple times to obtain an extract;

[0009] (3) concentrating the extract using a nanofiltration membrane to collect a permeate and a retentate;

[0010] (4) adjusting the pH of the retentate solution 1 to 6.2-6.7 to obtain a solution to be treated;

[0011] (5) pumping the liquid to be treated into an electrodialysis-ultrafiltration coupling device for separation, wherein an ultrafiltration membrane I with a molecular weight cutoff of 2000-3000Da, an ultrafiltration membrane II with a molecular weight cutoff of 10000-20000Da, and an ultrafiltration membrane III with a molecular weight cutoff the same as that of the ultrafiltration membrane II are stacked in sequence between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device, and the treatment is performed until the conductivity of the solution in the desalination chamber is less than 300 μs / cm, and the separation is completed, and the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are collected respectively;

[0012] (6) using a macroporous adsorption resin to adsorb and treat the ionic phase II, and then using a low alcohol solution and a high alcohol solution to perform phase analysis in stages, respectively, to obtain a low alcohol analysis solution and a high alcohol analysis solution;

[0013] (7) Concentrating the high alcohol analytical solution to obtain a retentate solution 2, mixing the retentate solution 2 and chlorogenic acid seed crystals, stirring and crystallizing, filtering to obtain a filtrate 1 and a filter cake 1, refining the filter cake 1 to obtain a filtrate 2 and a filter cake 2, and drying the filter cake 2 to obtain high-purity chlorogenic acid;

[0014] (8) The ion phase I is concentrated by a reverse osmosis membrane to obtain a retentate III, and the retentate III is successively subjected to thermal concentration and spray drying to obtain chlorogenic acid substances.

[0015] Preferably, in step (2), the concentration of the ethanol solution is 10-40 v / v%, and in a single extraction, the weight ratio of stevia powder to ethanol solution is 1:(5-20); and / or the extraction temperature is 30-60° C., and the single extraction time is 0.5-2 h.

[0016] Preferably, in step (3), the molecular weight cutoff of the nanofiltration membrane is 200-800Da, the membrane pressure during concentration is 1.5-3.0MPa, and the concentration temperature is 30-60°C; and / or when the retentate solid content is concentrated to 10-20wt%, water with half the volume of the retentate is added to the retentate to wash the retentate, and this is repeated 3-5 times, and the retentate and permeate are collected, and the permeate is used as recovered ethanol for stevia extraction.

[0017] Preferably, in step (4), an alkaline solution is used to adjust the pH of the retentate 1, the concentration of the alkaline solution is 5-40wt%, and the alkaline solution is one of K2CO3, KHCO3, NaHCO3, and Na2CO3.

[0018] Preferably, in step (5), the effective area of ​​ultrafiltration membrane I, ultrafiltration membrane II, and ultrafiltration membrane III is 30-40 cm 2 , the electric field strength during separation is 20-25V / cm; and / or the flow rate of the treated liquid during separation is 20-40ml / min, the pH of the solution in the anion chamber I is controlled to be 3.5-5.0, and the pH of the solution in the anion chamber II is controlled to be 2.5-3.5 during the separation process; and / or the pH of the solution in the anion chamber I and the anion chamber II is adjusted in real time using a hydrochloric acid solution.

[0019] Preferably, in step (5), the desalted phase is adsorbed, impurity-removed, and analyzed by a macroporous adsorption resin, and then desalted by a cationic resin and decolorized by an anionic resin, and concentrated and dried to obtain a stevioside product.

[0020] Preferably, in step (6), during adsorption, the feed flow rate of ionic phase II is 1-3BV / h, and the dry matter in ionic phase II is controlled to be 15-20% of the resin mass during feeding; and / or the concentrations of the low alcohol solution and the high alcohol solution are 25-35% v / v and 60-70% v / v, respectively; and / or the amounts of the low alcohol solution and the high alcohol solution are 2-3BV and 1.5-3BV of the resin volume, respectively; and / or the decomposition speed of the low alcohol solution and the high alcohol solution is 0.5-3BV / h; and / or the low alcohol decomposed solution is removed from the alcohol solvent and then merged into the ionic phase I.

[0021] Preferably, in step (7), the solid content of the second retentate is 15-20 wt%, the concentration of ethanol in the second retentate is 25-35% v / v; and / or the amount of chlorogenic acid seed crystals added is 0.2-0.5 wt% of the solid content in the second retentate; and / or the temperature of the stirred crystallization treatment is 10-35 ° C, and the time is 8-24h;

[0022] Preferably, in step (7), the process of refining filter cake 1 is: mixing filter cake 1 and pure water in a weight ratio of 1: (2-3), stirring at 70-80°C until the solid is completely dissolved, then cooling to 20-30°C within 4-8h, and filtering; filtrate 1 and filtrate 2 are combined into the next batch of ionic phase II for the next round of treatment.

[0023] Preferably, in step (8), the temperature of thermal concentration is 60-75°C, and the vacuum degree is -0.07 to -0.1 MPa; and / or the air inlet temperature during spray drying is 160-190°C, and the air outlet temperature is 70-95°C.

[0024] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. The present invention uses stevia as a raw material and uses an ethanol solution of a certain concentration for extraction to obtain an extract. In order to facilitate the subsequent use of electrodialysis-ultrafiltration coupling technology to separate chlorogenic acid and chlorogenic acid-like substances in the extract, the present invention concentrates the extract and adjusts the pH value, and recovers ethanol during the concentration process, so that the waste liquid is recycled and the extraction cost of chlorogenic acid is reduced.

[0026] 2. In order to separate chlorogenic acid and chlorogenic acid-like substances in the extract, the present invention effectively adjusts the electric field strength during electrodialysis treatment, and effectively adjusts the pH of the solution in anion chamber I and anion chamber II during the separation process, thereby ensuring a good separation effect.

[0027] 3. The present invention uses a macroporous adsorption resin with a cationic group to treat the ionic phase II, and then uses a low alcohol solution and a high alcohol solution for analysis, respectively. By adjusting the adsorption and analysis conditions, the chlorogenic acid and chlorogenic acid-like substances adsorbed on the resin are separated.

[0028] 4. The present invention concentrates the high-alcohol analytical solution containing chlorogenic acid, and then adds chlorogenic acid seed crystals for crystallization. By controlling the solid content of the retentate II, the amount of chlorogenic acid seed crystals added, and the conditions of crystallization and refining, a high content of chlorogenic acid is obtained.

[0029] 5. The present invention processes the ion phase I to recover chlorogenic acid substances, and processes the dilution phase to recover stevioside products, thereby greatly improving the utilization rate of stevia extract. The entire process generates less waste liquid and waste materials, and is economical and environmentally friendly. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] In order to solve the problems pointed out in the background technology, the present invention discloses the following technical solutions:

[0033] A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, comprising the following steps:

[0034] (1) crushing dried stevia leaves to obtain stevia powder;

[0035] (2) using ethanol solution as a raw material, repeatedly extracting the stevia powder for multiple times to obtain an extract;

[0036] (3) concentrating the extract using a nanofiltration membrane to collect a permeate and a retentate;

[0037] (4) adjusting the pH of the retentate solution 1 to 6.2-6.7 to obtain a solution to be treated;

[0038] (5) the treated liquid is pumped into an electrodialysis-ultrafiltration coupling device for separation, wherein an ultrafiltration membrane I, an ultrafiltration membrane II, and an ultrafiltration membrane III having the same molecular weight cutoff as that of the ultrafiltration membrane II are sequentially stacked between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device, and the treatment is performed until the conductivity of the solution in the desalination chamber is less than 300 μs / cm, and the separation is completed, and the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are respectively collected;

[0039] (6) using a macroporous adsorption resin to adsorb and treat the ionic phase II, and then using a low alcohol solution and a high alcohol solution to perform phase analysis in stages, respectively, to obtain a low alcohol analysis solution and a high alcohol analysis solution;

[0040] (7) Concentrating the high alcohol analytical solution to obtain a retentate solution 2, mixing the retentate solution 2 and chlorogenic acid seed crystals, stirring and crystallizing, filtering to obtain a filtrate 1 and a filter cake 1, refining the filter cake 1 to obtain a filtrate 2 and a filter cake 2, and drying the filter cake 2 to obtain chlorogenic acid;

[0041] (8) The ion phase I is concentrated by a reverse osmosis membrane to obtain a retentate III, and the retentate III is sequentially subjected to thermal concentration and spray drying to obtain a chlorogenic acid product.

[0042] In step (1):

[0043] First, the dried stevia leaves are crushed to facilitate subsequent extraction. The specific crushing conditions are conventional conditions in the art, so they are not described in detail.

[0044] In step (2):

[0045] In order to better extract the active ingredients in stevia, it is necessary to reasonably adjust the extraction conditions, such as the concentration of ethanol solution, the amount of ethanol solution and the extraction temperature.

[0046] In some embodiments of the present invention, the concentration of the ethanol solution is 10-40% v / v, and more preferably 10% v / v, 15% v / v, 20% v / v, 25% v / v, 30% v / v, 35% v / v, 35% v / v, but not limited thereto.

[0047] In some embodiments of the present invention, the weight ratio of the stevia powder to the ethanol solution is 1:(5-10), specifically, preferably 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, but not limited thereto.

[0048] In some embodiments of the present invention, the extraction temperature is 30-60°C, specifically, preferably 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, but not limited thereto.

[0049] In some embodiments of the present invention, the extraction can be repeated 2-6 times, and the single extraction time is 0.5-2h. Specifically, the single extraction time is 0.5h, 1h, 1.5h, 2h, but not limited thereto.

[0050] In step (3):

[0051] In order to recover the ethanol in the extract and facilitate the subsequent electrodialysis-ultrafiltration coupling treatment, the extract was concentrated using a nanofiltration membrane.

[0052] In some embodiments of the present invention, the molecular weight cutoff of the nanofiltration membrane is 200-800Da, the membrane pressure during concentration is 1.5-3.0MPa, and the concentration temperature is 30-60°C; when the retentate solid content is concentrated to 10-20wt%, water with half the volume of the retentate is added to the retentate, and the retentate solid content is continued to be 10-20wt%, and this is repeated 3-5 times, and the retentate and permeate are collected, and the permeate is used as recovered ethanol for stevia extraction.

[0053] The above process controls the electrodialysis-ultrafiltration coupling separation effect by effectively controlling the solid content of the retentate 1. If the solid content of the retentate 1 is high, the separation effect is poor at the same flow rate and electric field strength during the subsequent electrodialysis-ultrafiltration coupling, while if the solid content is low, the processing capacity of the electrodialysis-ultrafiltration coupling will increase, increasing the cost.

[0054] In step (4):

[0055] In order to further ensure the separation effect during electrodialysis-ultrafiltration coupling, the pH of the treated liquid needs to be reasonably adjusted so that the phenolic hydroxyl and carboxyl groups in the chlorogenic acid structure in the solution can be combined with potassium ions or sodium ions, thus becoming ionic and thus separated during electrodialysis-ultrafiltration coupling. If the pH is too high, the product will be in contact with air for a long time, and anthraquinone reaction will occur, thereby being destroyed, which will affect the content and yield of the product; if the pH is too low, some effective products cannot be combined with sodium ions and potassium ions, thus affecting the electrodialysis-ultrafiltration coupling separation effect.

[0056] In some embodiments of the present invention, an alkaline solution is used to adjust the pH of the retentate solution 1, the concentration of the alkaline solution is 5-40wt%, and the alkaline solution is one of K2CO3, KHCO3, NaHCO3, and Na2CO3. When adjusting the pH, specifically, the pH of the liquid to be treated is preferably 6.2, 6.3, 6.4, 6.5, 6.6, or 6.7, but is not limited thereto.

[0057] In step (5):

[0058] When electrodialysis-ultrafiltration coupling is used to treat the liquid to be treated, reasonable control conditions are required to ensure good separation effect.

[0059] In some embodiments of the present invention, the molecular weight cutoff of the ultrafiltration membrane I is 2000-3000Da; the molecular weight cutoff of the ultrafiltration membrane II and the ultrafiltration membrane III is 10000-20000Da. Substances with chlorogenic acid structure in the liquid to be treated all pass through the ultrafiltration membrane II, while chlorogenic acid, neochlorogenic acid, and cryptochlorogenic acid pass through the ultrafiltration membrane I, and isochlorogenic acid substances are retained between the ultrafiltration membrane I and the ultrafiltration membrane II; after the separation, chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, etc. are enriched in the anion chamber II, and isochlorogenic acid substances such as isochlorogenic acid A, isochlorogenic acid B, and isochlorogenic acid C in the liquid to be treated are enriched in the anion chamber I.

[0060] In some embodiments of the present invention, the effective area of ​​ultrafiltration membrane I, ultrafiltration membrane II, and ultrafiltration membrane III is 30-40 cm 2 .

[0061] In some embodiments of the present invention, the electric field strength during separation is 20-25V / cm, and is preferably 20V / cm, 21V / cm, 22V / cm, 23V / cm, 24V / cm, and 25V / cm, but is not limited thereto. During separation, if the electric field strength is too large, some impurities will also pass through the ultrafiltration membrane I and the ultrafiltration membrane II, thereby affecting the purity of the product; if the electric field strength is too small, more small molecular ions will pass through the ultrafiltration membrane I and the ultrafiltration membrane II, affecting the conductivity of the solution in the desalination chamber, affecting the endpoint judgment, and thus reducing the product yield.

[0062] In some embodiments of the present invention, the flow rate of the treated liquid is 20-40ml / min, specifically, preferably 20ml / min, 25ml / min, 30ml / min, 35ml / min, 40ml / min, but not limited thereto. During separation, if the flow rate of the treated liquid is too large, more small molecule ions will pass through ultrafiltration membrane I and ultrafiltration membrane II, affecting the conductivity of the solution in the desalination chamber, affecting the endpoint judgment, thereby reducing the product yield, and also increasing the separation energy consumption of the delivery pump. If the flow rate of the treated liquid is too small, some impurities will also pass through ultrafiltration membrane I and ultrafiltration membrane II, affecting the purity of the product.

[0063] In some embodiments of the present invention, during the separation process, the pH of the solution in the anion chamber I is adjusted to 3.5-5.0 in real time by adding hydrochloric acid solution to the solution in the anion chamber I and the anion chamber II, and the pH of the solution in the anion chamber II is adjusted to 2.5-3.5, thereby ensuring the separation effect and the stability of the effective product. Specifically, the pH of the solution in the anion chamber I is preferably 3.5, 4.0, 4.5, 5.0, but not limited thereto; the pH of the solution in the anion chamber II is controlled to 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, but not limited thereto.

[0064] For the solution in the anion chamber I, if the pH is too low, the solubility of the subsequent ion phase I concentration will be affected, resulting in the precipitation of some sticky impurities during concentration, affecting the product yield and normal operation; if the pH is too high, the ion phase I will cause the product to be destroyed during the separation process, the subsequent reverse osmosis and thermal concentration process, and thus affect the product yield. For the solution in the anion chamber II, if the pH is too low, the chlorogenic acid and impurities will be firmly adsorbed on the resin during the subsequent resin adsorption treatment, affecting the low alcohol analysis and impurity removal effect; if the pH is too high, the chlorogenic acid substances will be weakly adsorbed on the resin, resulting in the loss of the active ingredient in the effluent, and if the pH is too high, the chlorogenic acid will be destroyed.

[0065] In step (6):

[0066] A macroporous adsorption resin with a cationic group is used to purify chlorogenic acid in the ionic phase II. The type of the macroporous adsorption resin with a cationic group can preferably be one of the SD300 resin of Zhejiang Zhengguang Industrial Co., Ltd., the DA201-CB6 resin of Jiangsu Suqing Water Treatment Engineering Group Co., Ltd., and the LSA-37 resin of Xi'an Lanxiao Technology.

[0067] In some embodiments of the present invention, the feed flow rate of ionic phase II is 1-3BV / h. Specifically, the feed flow rate is preferably 1BV / h, 1.5BV / h, 2.0BV / h, 2.5BV / h, 3BV / h, but not limited thereto.

[0068] In some embodiments of the present invention, for the selection of feed amount, the dry matter in ionic phase II is controlled to be 15-20% of the mass of the resin, so that the chlorogenic acid in ionic phase II is fully adsorbed by the resin. Specifically, the dry matter in ionic phase II is 15%, 16%, 17%, 18%, 19%, 20% of the mass of the resin, but not limited thereto.

[0069] In order to obtain high-purity chlorogenic acid from the chlorogenic acid adsorbed on the resin, the present invention first uses a low-alcohol solution to resolve chlorogenic acid substances such as neochlorogenic acid and cryptochlorogenic acid adsorbed on the resin, and then uses a high-alcohol solution to resolve the chlorogenic acid adsorbed on the resin.

[0070] During analysis, the concentrations of the low alcohol solution and the high alcohol solution have a great influence on the separation effect. For the low alcohol solution, if the concentration is too low, the impurities such as the new chlorogenic acid and the cryptochlorogenic acid on the resin cannot be analyzed, and the impurity removal effect is poor, which affects the later separation. If the concentration is too high, part of the chlorogenic acid will be analyzed, affecting the product yield. Therefore, the present invention controls the concentration of the low alcohol solution to 25-35v / v%, preferably 25v / v%, 30v / v%, and 35v / v%, but not limited thereto. For the high alcohol solution, if the concentration is too low, the chlorogenic acid on the resin cannot be fully analyzed, and if the concentration is too high, not only the energy consumption is high, but also the analysis rate will decrease. Therefore, the present invention controls the concentration of the high alcohol solution to 60-70v / v%; preferably 62v / v%, 64v / v%, 66v / v%, 68v / v%, and 70v / v%, but not limited thereto.

[0071] In some embodiments of the present invention, the amount of the low alcohol solution and the high alcohol solution is 2-3BV and 1.5-3BV of the resin volume, respectively. Specifically, the amount of the low alcohol solution is preferably 2BV, 2.2BV, 2.4BV, 2.6BV, 3.0BV of the resin volume, but not limited thereto; the amount of the high alcohol solution is preferably 1.5BV, 2BV, 2.5BV, 3BV of the resin volume, but not limited thereto.

[0072] In some embodiments of the present invention, the resolution rate of the low alcohol solution and the high alcohol solution is 0.5-3BV / h. Specifically, the resolution rate of the low alcohol solution and the high alcohol solution is preferably 0.5BV / h, 1BV / h, 1.5BV / h, 2BV / h, 2.5BV / h, 3BV / h, but not limited thereto.

[0073] In step (7):

[0074] The present invention concentrates the high alcohol analytical solution, then adds chlorogenic acid seed crystals to mix, and crystallizes under certain conditions, thereby recovering high-purity chlorogenic acid. In the above process, the solid content of the second retentate, the concentration of ethanol in the second retentate, the amount of chlorogenic acid seed crystals added, the temperature and time of crystallization, etc. will affect the recovery effect of chlorogenic acid. For the solid content of the second retentate, if the solid content is too high, a small amount of impurities will precipitate during the subsequent crystallization, affecting the content of chlorogenic acid; if the solid content is too low, the saturated solubility is not reached, and some chlorogenic acid cannot be completely crystallized, thereby affecting the yield of chlorogenic acid. For the concentration of ethanol in the retentate, if the concentration is too high, the chlorogenic acid solution has a high solubility and cannot be completely precipitated in the subsequent crystallization process, affecting the yield; if the concentration is too low, some impurities precipitate and crystallize together with chlorogenic acid, affecting the primary crystal content, and then affecting the content and yield in the refining process. For the amount of chlorogenic acid seed crystals added, if the amount added is too small, the crystallization yield is low, and if the amount added is too large, the yield and content of chlorogenic acid are almost unaffected, but the cost will increase.

[0075] In some embodiments of the present invention, the solid content of the retentate II is 15-20wt%, preferably 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, but not limited thereto. The concentration of ethanol in the retentate II is 25-35% v / v, preferably 25% v / v, 30% v / v, 35% v / v, but not limited thereto. The amount of chlorogenic acid seed crystals added is 0.2-0.5wt% of the solid content in the retentate II, preferably 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, but not limited thereto. The temperature of the stirred crystallization treatment is 10-35°C and the time is 8-24h.

[0076] In some embodiments of the present invention, the process of refining filter cake 1 is: mixing filter cake 1 and pure water in a weight ratio of 1: (2-3), stirring at 70-80°C until the solid is completely dissolved, then cooling to 20-30°C and filtering.

[0077] In some embodiments of the present invention, filtrate 1 and filtrate 2 are combined into the next batch of ionic phase II for the next round of treatment, so as to fully recover chlorogenic acid.

[0078] In step (8):

[0079] The ion phase I is concentrated by reverse osmosis membrane, heat concentrated, and spray dried to recover the chlorogenic acid product, which contains a small amount of chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, isochlorogenic acid B, isochlorogenic acid A, isochlorogenic acid C, etc. The present invention recovers this part, further improving the enterprise's profit.

[0080] In some embodiments of the present invention, the temperature of the thermal concentration is 60-75° C., and the vacuum degree is -0.07 to -0.1 MPa.

[0081] In some embodiments of the present invention, during the spray drying, the air inlet temperature is 160-190°C, and the air outlet temperature is 70-95°C.

[0082] In the present invention, the desalted phase is adsorbed by a macroporous adsorption resin, impurities are removed, and analyzed, and then cation desalination, anion decolorization, concentration, and drying are performed to obtain a stevioside product. The preparation of stevioside is recovered by conventional methods in the art, so it will not be described in detail.

[0083] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0084] In the following examples, unless otherwise specified, the raw materials are all commercially available and the conditions are all conventional conditions in the art.

[0085] Example 1

[0086] A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, comprising the following steps:

[0087] (1) crushing dried stevia leaves to obtain stevia powder;

[0088] (2) Stevia powder and 30 v / v% ethanol solution were mixed at a weight ratio of 1:10, extracted at 40°C for 1 hour, filtered, and the residue was further mixed with 30 v / v% ethanol solution at a weight ratio of 1:10 for extraction. The extraction was repeated 4 times, and the filtrates were combined to obtain 119.6 kg of extract, with a solid content of 1.08 wt%, a chlorogenic acid content of 2.33 wt% in the dry matter, and a total chlorogenic acid content of 9.02 wt%;

[0089] (3) using a nanofiltration membrane with a molecular weight cutoff of 400Da to concentrate the extract under the conditions of a membrane pressure of 2.5MPa and a temperature of 40°C, and when the solid content of the retentate is 17.0wt%, adding half of its volume of water to the retentate, and continuing to concentrate until the solid content of the retentate is 17.0wt%, repeating this process 4 times, collecting a permeate I and a retentate I with a solid content of 17.0wt%; the permeate I is used as recovered ethanol for the extraction of stevia;

[0090] (4) adding K2CO3 with a concentration of 15 wt% to the retentate one to adjust the pH of the retentate one to 6.5, thereby obtaining a liquid to be treated;

[0091] (5) The treated liquid was pumped into an electrodialysis-ultrafiltration coupling device at a flow rate of 32 ml / min for separation. An ultrafiltration membrane I with a molecular weight cutoff of 2500 Da, an ultrafiltration membrane II with a molecular weight cutoff of 15000 Da, and an ultrafiltration membrane III with the same molecular weight cutoff as that of the ultrafiltration membrane II were stacked in sequence between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device. The effective area of ​​the ultrafiltration membrane I, the ultrafiltration membrane II, and the ultrafiltration membrane III was 36 cm 2 , under the condition of electric field strength of 23V / cm, the conductivity of the solution in the desalination chamber is treated to be less than 300μs / cm, and the pH of the solution in the anion chamber I is controlled to be 4.2, and the pH of the solution in the anion chamber II is controlled to be 3.0 during the separation process; after the separation is completed, the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are collected respectively;

[0092] (6) The ion phase II is pumped into a resin column filled with a macroporous adsorption resin having a cationic group (SD300 resin of Zhejiang Zhengguang Industrial Co., Ltd.) at a rate of 2BV / h for adsorption, and the dry matter in the ion phase II is controlled to be 18% of the resin mass during feeding; after the adsorption is completed, an ethanol solution with a resin volume of 2.5BV and a concentration of 32% v / v is first pumped into the resin column at a rate of 2.0BV / h for analysis, and the low-alcohol analysis solution is collected; then, an ethanol solution with a resin volume of 2.5BV and a concentration of 66% v / v is pumped into the resin column at a rate of 2.0BV / h for analysis, and the high-alcohol analysis solution is collected; the low-alcohol analysis solution is de-alcoholized and then merged into the ion phase I;

[0093] (7) The high alcohol analysis solution was concentrated to a solid content of 18 wt% and an ethanol concentration of 32% v / v; the retentate 2 was obtained, the retentate 2 was mixed with chlorogenic acid seeds with a purity of 98% (the amount of chlorogenic acid seeds added was 0.4 wt% of the solid content in the retentate 2), stirred and crystallized at 25°C for 18 hours, filtered, and filtrate 1 and filter cake 1 were obtained. The filter cake 1 and pure water were mixed in a weight ratio of 1:2, stirred at 76°C until the solid was completely dissolved, and then cooled to 25°C within 6 hours, filtered, and filtrate 2 and filter cake 2 were obtained; the filter cake 2 was dried to obtain 26.3 g of high-purity chlorogenic acid, with a chlorogenic acid content of 99.3 wt% and a yield of 86.8%. The filtrate 1 and the filtrate 2 were combined into the next batch of ionic phase II for the next round of treatment;

[0094] (8) The ion phase I was concentrated by reverse osmosis membrane to obtain retentate III. The retentate III was thermally concentrated to a solid content of 48 wt % at a temperature of 70 ° C and a vacuum degree of -0.08 MPa, and then spray-dried (inlet temperature 180 ° C, outlet temperature 85 ° C) to obtain 173.8 g of chlorogenic acid product with a total chlorogenic acid content of 47.8 wt %.

[0095] Example 2

[0096] A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, comprising the following steps:

[0097] (1) crushing dried stevia leaves to obtain stevia powder;

[0098] (2) Stevia powder and 40 v / v% ethanol solution were mixed at a weight ratio of 1:5, extracted at 30°C for 0.5h, filtered, and the residue was further mixed with 40 v / v% ethanol solution at a weight ratio of 1:5 for extraction. The extraction was repeated 6 times, and the filtrates were combined to obtain 89.5 kg of extract, with a solid content of 1.38 wt%, a chlorogenic acid content of 2.34 wt% in the dry matter, and a total chlorogenic acid content of 8.84 wt%;

[0099] (3) using a nanofiltration membrane with a molecular weight cutoff of 200 Da to concentrate the extract under the conditions of a membrane pressure of 3.0 MPa and a temperature of 30° C., when the solid content of the retentate is 10.0 wt%, adding half the volume of water to the retentate, and continuing to concentrate until the solid content of the retentate is 10.0 wt%. Repeating this process for 3 times, collecting a permeate I and a retentate I with a solid content of 10.0 wt%. The permeate I is used as recovered ethanol for the extraction of stevia.

[0100] (4) adding KHCO3 with a concentration of 5 wt% to the retentate one to adjust the pH of the retentate one to 6.7, thereby obtaining a liquid to be treated;

[0101] (5) The treated liquid was pumped into an electrodialysis-ultrafiltration coupling device at a flow rate of 20 ml / min for separation. An ultrafiltration membrane I with a molecular weight cutoff of 2000 Da, an ultrafiltration membrane II with a molecular weight cutoff of 10000 Da, and an ultrafiltration membrane III with a molecular weight cutoff of the same as that of the ultrafiltration membrane II were stacked in sequence between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device. The effective area of ​​the ultrafiltration membrane I, the ultrafiltration membrane II, and the ultrafiltration membrane III was 30 cm 2 , under the condition of electric field strength of 20V / cm, the conductivity of the solution in the desalination chamber is treated to be less than 300μs / cm, and the pH of the solution in the anion chamber I is controlled to be 3.5, and the pH of the solution in the anion chamber II is controlled to be 2.5 during the separation process; after the separation is completed, the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are collected respectively;

[0102] (6) The ion phase II is pumped into a resin column filled with a macroporous adsorption resin with cationic groups (DA201-CB6 resin from Jiangsu Suqing Water Treatment Engineering Group Co., Ltd.) at a rate of 1.0 BV / h for adsorption, and the dry matter in the ion phase II is controlled to be 15% of the resin mass during feeding; after the adsorption is completed, a resin volume of 2.0 BV and a concentration of 25% v / v ethanol solution is first pumped into the resin column at a rate of 0.5 BV / h for analysis, and the low-alcohol analysis solution is collected; then a resin volume of 3.0 BV and a concentration of 70% v / v ethanol solution is pumped into the resin column at a rate of 0.5 BV / h for analysis, and the high-alcohol analysis solution is collected; the low-alcohol analysis solution is de-alcoholized and then merged into the ion phase I;

[0103] (7) The high alcohol analysis solution was concentrated to a solid content of 20wt% and an ethanol concentration of 35% v / v; the retentate 2 was obtained, the retentate 2 was mixed with chlorogenic acid seeds with a purity of 98% (the amount of chlorogenic acid seeds added was 0.3wt% of the solid content in the retentate 2), stirred and crystallized at 10°C for 8h, filtered, and filtrate 1 and filter cake 1 were obtained. The filter cake 1 and pure water were mixed in a weight ratio of 1:3, stirred at 70°C until the solid was completely dissolved, and then cooled to 20°C within 4h, filtered, and filtrate 2 and filter cake 2 were obtained; the filter cake 2 was dried to obtain 25.0g of high-purity chlorogenic acid, with a chlorogenic acid content of 98.6wt% and a yield of 85.3%. The filtrate 1 and filtrate 2 were combined into the next batch of ionic phase II for the next round of treatment;

[0104] (8) The ion phase I was concentrated by a reverse osmosis membrane to obtain a retentate III. The retentate III was thermally concentrated to a solid content of 55 wt % at a temperature of 60 ° C and a vacuum degree of -0.1 MPa, and then spray-dried (inlet temperature 160 ° C, outlet temperature 70 ° C) to obtain 164.8 g of chlorogenic acid product with a total chlorogenic acid content of 46.3 wt %.

[0105] Example 3

[0106] A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, comprising the following steps:

[0107] (1) crushing dried stevia leaves to obtain stevia powder;

[0108] (2) Stevia powder and 10 v / v% ethanol solution were mixed at a weight ratio of 1:20, extracted at 60°C for 2.0 h, filtered, and the residue was further mixed with 10 v / v% ethanol solution at a weight ratio of 1:20 for extraction. The extraction was repeated twice, and the filtrates were combined to obtain 119.7 kg of extract, with a solid content of 1.05 wt%, a chlorogenic acid content of 2.31 wt% in the dry matter, and a total chlorogenic acid content of 8.95 wt%;

[0109] (3) using a nanofiltration membrane with a molecular weight cutoff of 800Da to concentrate the extract under the conditions of a membrane pressure of 1.5MPa and a temperature of 60°C, and when the solid content of the retentate is 20.0wt%, adding half of its volume of water to the retentate, and continuing to concentrate until the solid content of the retentate is 20.0wt%, repeating this process 5 times, collecting a permeate I and a retentate I with a solid content of 20.0wt%; the permeate I is used as recovered ethanol for the extraction of stevia;

[0110] (4) adding NaHCO3 with a concentration of 40 wt% to the retentate one to adjust the pH of the retentate one to 6.2, thereby obtaining a liquid to be treated;

[0111] (5) The treated liquid was pumped into an electrodialysis-ultrafiltration coupling device at a flow rate of 40 ml / min for separation. An ultrafiltration membrane I with a molecular weight cutoff of 3000 Da, an ultrafiltration membrane II with a molecular weight cutoff of 20000 Da, and an ultrafiltration membrane III with the same molecular weight cutoff as that of the ultrafiltration membrane II were stacked in sequence between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device. The effective area of ​​the ultrafiltration membrane I, the ultrafiltration membrane II, and the ultrafiltration membrane III was 40 cm 2, under the condition of electric field strength of 25V / cm, the conductivity of the solution in the desalination chamber is treated to be less than 300μs / cm, and the pH of the solution in the anion chamber I is controlled to be 5.0, and the pH of the solution in the anion chamber II is controlled to be 3.5 during the separation process; after the separation, the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are collected respectively;

[0112] (6) Pumping ion phase II into a resin column filled with a macroporous adsorption resin with cationic groups (Xi'an Lanxiao Technology LSA-37 resin) at a rate of 3.0 BV / h for adsorption, and controlling the dry matter in ion phase II to be 20% of the resin mass during feeding; after the adsorption, first pumping a resin volume of 3.0 BV and a concentration of 35% v / v ethanol solution into the resin column at a rate of 3.0 BV / h for analysis, and collecting the low-alcohol analysis solution; then pumping a resin volume of 1.5 BV and a concentration of 60% v / v ethanol solution into the resin column at a rate of 3.0 BV / h for analysis, and collecting the high-alcohol analysis solution; the low-alcohol analysis solution is de-alcoholized and then merged into the ion phase I;

[0113] (7) The high alcohol analysis solution was concentrated to a solid content of 15wt% and an ethanol concentration of 25% v / v; the retentate 2 was obtained, the retentate 2 was mixed with chlorogenic acid seeds with a purity of 98% (the amount of chlorogenic acid seeds added was 0.5wt% of the solid content in the retentate 2), stirred and crystallized at 35°C for 24h, filtered, and filtrate 1 and filter cake 1 were obtained. The filter cake 1 and pure water were mixed in a weight ratio of 1:2, stirred at 80°C until the solid was completely dissolved, and then cooled to 30°C within 8h, filtered, and filtrate 2 and filter cake 2 were obtained; filter cake 2 was dried to obtain 25.3g of high-purity chlorogenic acid with a chlorogenic acid content of 98.5wt% and a yield of 85.8%. The filtrate 1 and filtrate 2 were combined into the next batch of ionic phase II for the next round of treatment;

[0114] (8) The ion phase I was concentrated by a reverse osmosis membrane to obtain a retentate III. The retentate III was thermally concentrated to a solid content of 40 wt % at a temperature of 75 ° C and a vacuum degree of -0.07 MPa, and then spray-dried (inlet temperature 190 ° C, outlet temperature 90 ° C) to obtain 169.9 g of chlorogenic acid product with a total chlorogenic acid content of 46.7 wt %.

[0115] Example 4

[0116] A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, comprising the following steps:

[0117] (1) crushing dried stevia leaves to obtain stevia powder;

[0118] (2) Stevia powder and 25 v / v% ethanol solution were mixed at a weight ratio of 1:15, extracted at 45°C for 1.5 hours, filtered, and the residue was further mixed with 25 v / v% ethanol solution at a weight ratio of 1:15 for extraction. The extraction was repeated 5 times, and the filtrates were combined to obtain 224.8 kg of extract, with a solid content of 0.59 wt%, a chlorogenic acid content of 2.26 wt% in the dry matter, and a total chlorogenic acid content of 8.78 wt%;

[0119] (3) using a nanofiltration membrane with a molecular weight cutoff of 400 Da to concentrate the extract under the conditions of a membrane pressure of 2.0 MPa and a temperature of 45° C., when the solid content of the retentate is 14.0 wt%, adding half the volume of water to the retentate, and continuing to concentrate until the solid content of the retentate is 14.0 wt%. Repeating this process 4 times, collecting a permeate I and a retentate I with a solid content of 14.0 wt%. The permeate I is used as recovered ethanol for stevia extraction;

[0120] (4) adding 30 wt % Na2CO3 to the retentate one to adjust the pH of the retentate one to 6.4, thereby obtaining a solution to be treated;

[0121] (5) The treated liquid was pumped into an electrodialysis-ultrafiltration coupling device at a flow rate of 27 ml / min for separation. An ultrafiltration membrane I with a molecular weight cutoff of 2500 Da, an ultrafiltration membrane II with a molecular weight cutoff of 17000 Da, and an ultrafiltration membrane III with the same molecular weight cutoff as that of the ultrafiltration membrane II were stacked in sequence between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device. The effective area of ​​the ultrafiltration membrane I, the ultrafiltration membrane II, and the ultrafiltration membrane III was 32 cm 2 , under the condition of electric field strength of 22V / cm, the conductivity of the solution in the desalination chamber is treated to be less than 300μs / cm, and the pH of the solution in the anion chamber I is controlled to be 4.7, and the pH of the solution in the anion chamber II is controlled to be 3.2 during the separation process; after the separation, the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are collected respectively;

[0122] (6) The ion phase II is pumped into a resin column filled with a macroporous adsorption resin having a cationic group (SD300 resin of Zhejiang Zhengguang Industrial Co., Ltd.) at a rate of 2.5 BV / h for adsorption, and the dry matter in the ion phase II is controlled to be 16% of the resin mass during feeding; after the adsorption is completed, a resin volume of 2.6 BV and a concentration of 27% v / v ethanol solution is first pumped into the resin column at a rate of 1.5 BV / h for analysis, and the low-alcohol analysis solution is collected; then a resin volume of 2.0 BV and a concentration of 64% v / v ethanol solution is pumped into the resin column at a rate of 1.5 BV / h for analysis, and the high-alcohol analysis solution is collected; the low-alcohol analysis solution is de-alcoholized and then merged into the ion phase I;

[0123] (7) The high alcohol analysis solution was concentrated to a solid content of 16 wt% and an ethanol concentration of 28% v / v; the retentate 2 was obtained, the retentate 2 was mixed with chlorogenic acid seeds with a purity of 98% (the amount of chlorogenic acid seeds added was 0.3 wt% of the solid content in the retentate 2), stirred and crystallized at 18°C ​​for 14 h, filtered, and filtrate 1 and filter cake 1 were obtained. The filter cake 1 and pure water were mixed at a weight ratio of 1:3, stirred at 73°C until the solid was completely dissolved, and then cooled to 23°C within 5 h, filtered, and filtrate 2 and filter cake 2 were obtained; the filter cake 2 was dried to obtain 26.1 g of high-purity chlorogenic acid, with a chlorogenic acid content of 99.1 wt% and a yield of 86.3%. The filtrate 1 and the filtrate 2 were combined into the next batch of ionic phase II for the next round of treatment;

[0124] (8) The ion phase I was concentrated by reverse osmosis membrane to obtain retentate III. The retentate III was thermally concentrated to a solid content of 44 wt% under the conditions of a temperature of 64°C and a vacuum degree of -0.09 MPa, and then spray-dried (inlet temperature 175°C, outlet temperature 78°C) to obtain 174.7 g of chlorogenic acid product with a total chlorogenic acid content of 47.2 wt%.

[0125] Comparative Example 1

[0126] Compared with Example 1, the difference is that in step (3), the solid content of the retentate one is 5wt%, and the other conditions are compared with Example 1, and 21.7g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 97.5wt%, and the yield is 70.3%.

[0127] Comparative Example 2

[0128] Compared with Example 1, the difference is that in step (3), the solid content of the retentate one is 25wt%, and the other conditions are compared with Example 1, and 20.8g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 96.4wt%, and the yield is 66.6%.

[0129] Comparative Example 3

[0130] Compared with Example 1, the difference is that in step (4), the pH of the liquid to be treated is 5.0, and the other conditions are compared with Example 1, and 9.1 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 91.6 wt%, and the yield is 27.7%.

[0131] Comparative Example 4

[0132] Compared with Example 1, the difference is that in step (4), the pH of the liquid to be treated is 7.5, and the other conditions are the same as those in Example 1, and 14.5 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 93.4 wt%, and the yield is 45.0%.

[0133] Comparative Example 5

[0134] Compared with Example 1, the difference is that in step (5), the electric field strength is 10 V / cm, and the other conditions are the same as those in Example 1, and 19.8 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 96.1 wt%, and the yield is 63.2%.

[0135] Comparative Example 6

[0136] Compared with Example 1, the difference is that in step (5), the electric field strength is 35 V / cm, and the other conditions are the same as those in Example 1, and 17.7 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 96.2 wt%, and the yield is 56.6%.

[0137] Comparative Example 7

[0138] Compared with Example 1, the difference is that in step (5), the pH of the solution in anion chamber II is controlled to be 1.5 during the separation process, and the other conditions are the same as those in Example 1, and 20.8 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 95.4 wt%, and the yield is 65.9%.

[0139] Comparative Example 8

[0140] Compared with Example 1, the difference is that in step (5), the pH of the solution in the anion chamber II is controlled to be 4.5 during the separation process, and the other conditions are the same as those in Example 1, and 10.7 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 90.1 wt%, and the yield is 32.0%.

[0141] Comparative Example 9

[0142] Compared with Example 1, the difference is that in step (6), during the low alcohol analysis, the concentration of the ethanol solution is 15% v / v, and the other conditions are the same as those in Example 1, and 16.6 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 91.1 wt%, and the yield is 50.2%.

[0143] Comparative Example 10

[0144] Compared with Example 1, the difference is that in step (6), during the low alcohol analysis, the ethanol solution is 45% v / v, and the other conditions are the same as in Example 1, and 13.7 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 96.2 wt%, and the yield is 43.8%.

[0145] Comparative Example 11

[0146] Compared with Example 1, the difference is that in step (6), during the high alcohol analysis, the concentration of the ethanol solution is 50% v / v, and the other conditions are the same as in Example 1, and 16.5 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 95.0 wt%, and the yield is 52.1%.

[0147] Comparative Example 12

[0148] Compared with Example 1, the difference is that in step (7), the solid content of the retentate second is 8wt%, and the other conditions are the same as those in Example 1, and 11.6g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 98.7wt%, and the yield is 38.0%.

[0149] Comparative Example 13

[0150] Compared with Example 1, the difference is that in step (7), the solid content of the retentate second is 30wt%, and the other conditions are the same as those in Example 2, and 23.1g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 94.2wt%, and the yield is 72.3%.

[0151] Comparative Example 14

[0152] Compared with Example 1, the difference is that in step (7), the ethanol concentration in the retentate second is 15% v / v, and the other conditions are the same as those in Example 2, and 24.2 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 92.4 wt%, and the yield is 74.3%.

[0153] Comparative Example 15

[0154] Compared with Example 1, the difference is that in step (7), the ethanol concentration in the retentate second is 45% v / v; the other conditions are the same as those in Example 1, and 16.3 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 99.0 wt%, and the yield is 53.6%.

[0155] Comparative Example 16

[0156] Compared with Example 1, the difference is that in step (7), the amount of chlorogenic acid seed crystals added is 0.1wt% of the solid content in the retentate two, and the other conditions are the same as in Example 1, and 19.7g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 96.9wt%, and the yield is 63.4%.

[0157] Comparative Example 17

[0158] Compared with Example 1, the difference is that in step (7), the temperature of the stirred crystallization is 5°C, and the other conditions are the same as those in Example 1, and 27.8 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 94.3 wt%, and the yield is 87.1%.

[0159] Comparative Example 18

[0160] Compared with Example 1, the difference is that in step (7), the temperature of the stirred crystallization is 45°C, and the other conditions are the same as those in Example 1, and 15.3 g of high-purity chlorogenic acid is obtained, the chlorogenic acid content is 99.1 wt%, and the yield is 50.4%.

[0161] Comparative Example 19

[0162] Compared with Example 1, the difference is that in step (7), when the filter cake is refined, the temperature is lowered to 25° C. within 2 h. The other conditions are the same as those in Example 1, and 26.1 g of high-purity chlorogenic acid is obtained. The chlorogenic acid content is 95.6 wt% and the yield is 82.9%.

[0163] In summary, compared with the comparative example, the present invention treats the stevia extract by using membrane concentration, electrodialysis-ultrafiltration coupling, resin adsorption, gradient analysis and other methods, and optimizes the treatment conditions at each stage to obtain high-purity chlorogenic acid and chlorogenic acid-like substances, and does not generate a large amount of solid waste in the whole process, which is more environmentally friendly.

[0164] 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 efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia, characterized in that: The following steps are involved: (1) crushing dried stevia leaves to obtain stevia powder; (2) using ethanol solution as a raw material, repeatedly extracting the stevia powder for multiple times to obtain an extract; (3) concentrating the extract using a nanofiltration membrane to collect a permeate and a retentate; (4) adjusting the pH of the retentate solution 1 to 6.2-6.7 to obtain a solution to be treated; (5) pumping the liquid to be treated into an electrodialysis-ultrafiltration coupling device for separation, wherein an ultrafiltration membrane I with a molecular weight cutoff of 2000-3000Da, an ultrafiltration membrane II with a molecular weight cutoff of 10000-20000Da, and an ultrafiltration membrane III with a molecular weight cutoff the same as that of the ultrafiltration membrane II are stacked in sequence between the anion exchange membrane and the cation exchange membrane of the electrodialysis-ultrafiltration coupling device, and the treatment is performed until the conductivity of the solution in the desalination chamber is less than 300 μs / cm, and the separation is completed, and the ion phase I in the anion chamber I between the ultrafiltration membrane I and the ultrafiltration membrane II, the ion phase II in the anion chamber II between the ultrafiltration membrane I and the anion exchange membrane, and the desalinated phase in the desalination chamber between the ultrafiltration membrane II and the ultrafiltration membrane III are collected respectively; (6) using a macroporous adsorption resin with a cationic group to adsorb and treat the ionic phase II, and then using a low alcohol solution and a high alcohol solution to perform phase analysis in stages, respectively, to obtain a low alcohol analysis solution and a high alcohol analysis solution; (7) Concentrating the high alcohol analytical solution to obtain a retentate solution 2, mixing the retentate solution 2 and chlorogenic acid seed crystals, stirring and crystallizing, filtering to obtain a filtrate 1 and a filter cake 1, refining the filter cake 1 to obtain a filtrate 2 and a filter cake 2, and drying the filter cake 2 to obtain high-purity chlorogenic acid; (8) The ion phase I is concentrated by a reverse osmosis membrane to obtain a retentate III, and the retentate III is sequentially subjected to thermal concentration and spray drying to obtain chlorogenic acid substances.

2. A method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia according to claim 1, characterized in that: In step (2), the concentration of the ethanol solution is 10-40 v / v%, and in a single extraction, the weight ratio of stevia powder to ethanol solution is 1:(5-20); and / or the extraction temperature is 30-60° C., and the single extraction time is 0.5-2 h.

3. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia according to claim 1, characterized in that: In step (3), the molecular weight cutoff of the nanofiltration membrane is 200-800Da, the membrane pressure during concentration is 1.5-3.0MPa, and the concentration temperature is 30-60°C; and / or when the retentate solid content is concentrated to 10-20wt%, water with half the volume of the retentate is added to the retentate to wash the retentate, and this is repeated 3-5 times, and the retentate and permeate are collected, and the permeate is used as recovered ethanol for stevia extraction.

4. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia according to claim 1, characterized in that: In step (4), an alkaline solution is used to adjust the pH of the retentate solution 1, wherein the concentration of the alkaline solution is 5-40wt%, and the alkaline solution is one of K2CO3, KHCO3, NaHCO3, and Na2CO3.

5. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia according to claim 1, characterized in that: In step (5), the effective area of ​​ultrafiltration membrane I, ultrafiltration membrane II, and ultrafiltration membrane III is 30-40 cm 2 , the electric field strength during separation is 20-25V / cm; and / or the flow rate of the treated liquid during separation is 20-40ml / min, the pH of the solution in the anion chamber I is controlled to be 3.5-5.0, and the pH of the solution in the anion chamber II is controlled to be 2.5-3.5 during the separation process; and / or the pH of the solution in the anion chamber I and the anion chamber II is adjusted in real time using a hydrochloric acid solution.

6. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia according to claim 1, characterized in that: In step (5), the desalted phase is adsorbed, impurity-removed, and analyzed by a macroporous adsorption resin, and then desalted by a cationic resin and decolorized by an anionic resin, and concentrated and dried to obtain a stevioside product.

7. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from Stevia according to claim 1, characterized in that: In step (6), during adsorption, the feed flow rate of ionic phase II is 1-3BV / h, and the dry matter in ionic phase II is controlled to be 15-20% of the resin mass during feeding; and / or the concentrations of the low alcohol solution and the high alcohol solution are 25-35% v / v and 60-70% v / v, respectively; and / or the amounts of the low alcohol solution and the high alcohol solution are 2-3BV and 1.5-3BV of the resin volume, respectively; and / or the decomposition speed of the low alcohol solution and the high alcohol solution is 0.5-3BV / h; and / or the low alcohol decomposed solution is removed from the alcohol solvent and then merged into the ionic phase I.

8. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from stevia according to claim 1, characterized in that: In step (7), the solid content of the retentate II is 15-20 wt%, the concentration of ethanol in the retentate II is 25-35% v / v; and / or the amount of chlorogenic acid seed crystals added is 0.2-0.5 wt% of the solid content in the retentate II; and / or the temperature of the stirred crystallization treatment is 10-35°C and the time is 8-24 h.

9. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from Stevia according to claim 1, characterized in that: In step (7), the process of refining filter cake 1 is as follows: filter cake 1 and pure water are mixed in a weight ratio of 1:(2-3), stirred at 70-80°C until the solid is completely dissolved, then cooled to 20-30°C within 4-8 hours, and filtered; filtrate 1 and filtrate 2 are combined into the next batch of ionic phase II for the next round of treatment.

10. The method for efficiently extracting high-purity chlorogenic acid and chlorogenic acid-like substances from Stevia according to claim 1, characterized in that: In step (8), the temperature of thermal concentration is 60-75°C and the vacuum degree is -0.07 to -0.1 MPa; and / or the air inlet temperature during spray drying is 160-190°C and the air outlet temperature is 70-95°C.