阅读说明：本技术 一种从甜茶苷生产的副产物中分离鞣花酸的方法 (Method for separating ellagic acid from byproducts of rubusoside production ) 是由 李伟 黄华学 于 2021-08-25 设计创作，主要内容包括：一种从甜茶苷生产的副产物中分离鞣花酸的方法,包括以下步骤：(1)收集甜茶上柱流出液,浓缩：得甜茶多酚浓缩液；(2)加压水解：往所述甜茶多酚浓缩液中加入无机酸,加压保温水解,得水解物料；(3)用有机溶剂进行萃取,收集有机溶剂层；(4)碱水反萃取：将所述有机溶剂层用碱水溶液反萃取,收集碱水层；(5)酸化：将所述碱水层用盐酸调节pH值至酸性,析出固体,将固体过滤,干燥,得鞣花酸粗品；(6)结晶：将所述鞣花酸粗品溶解,脱色,冷冻析晶,即得鞣花酸产品。本发明将甜茶资源综合利用,变废为宝,鞣花酸收率高,所得鞣花酸产品中鞣花酸的含量高达97%以上。(A method for separating ellagic acid from a byproduct of rubusoside production, comprising the steps of: (1) collecting the effluent of the sweet tea column, and concentrating: obtaining sweet tea polyphenol concentrated solution; (2) pressurized hydrolysis: adding inorganic acid into the sweet tea polyphenol concentrated solution, pressurizing, preserving heat and hydrolyzing to obtain a hydrolyzed material; (3) extracting with organic solvent, and collecting organic solvent layer; (4) back extraction with alkaline water: back-extracting the organic solvent layer with an aqueous alkali solution, and collecting an aqueous alkali layer; (5) acidifying: adjusting the pH value of the alkaline water layer to acidity by using hydrochloric acid, separating out a solid, filtering the solid, and drying to obtain a crude ellagic acid product; (6) and (3) crystallization: and dissolving the crude ellagic acid product, decoloring, freezing and crystallizing to obtain an ellagic acid product. The sweet tea resources are comprehensively utilized, waste is turned into wealth, the ellagic acid yield is high, and the content of the ellagic acid in the obtained ellagic acid product is as high as more than 97%.)

1. A method for separating ellagic acid from a byproduct of rubusoside production, comprising the steps of:

(1) collecting and concentrating the effluent of the sweet tea column: collecting the column-loading effluent of the macroporous adsorbent resin column in the rubusoside production process, filtering with a nanofiltration membrane, and concentrating the nanofiltration membrane retentate to obtain rubusoside concentrate;

(2) pressurized hydrolysis: adding inorganic acid into the sweet tea polyphenol concentrated solution obtained in the step (1), pressurizing, and carrying out thermal insulation hydrolysis to obtain a hydrolyzed material;

(3) organic solvent extraction: cooling the hydrolyzed material obtained in the step (2) to room temperature, then extracting with an organic solvent, separating liquid, and collecting an organic solvent layer;

(4) back extraction with alkaline water: carrying out back extraction on the organic solvent layer obtained in the step (3) by using an aqueous alkali solution, separating liquid, and collecting an aqueous alkali layer;

(5) acidifying: adjusting the pH value of the alkaline water layer obtained in the step (4) to acidity by using hydrochloric acid, separating out solid, filtering the solid, and drying to obtain a crude ellagic acid product;

(6) and (3) crystallization: and (3) heating and dissolving the ellagic acid crude product obtained in the step (5) by using an ethanol water solution, adding a decoloring agent, keeping the temperature, stirring and decoloring, filtering while hot, freezing and crystallizing, filtering crystals, and drying to obtain an ellagic acid product.

2. The method for separating ellagic acid from a byproduct of rubusoside production according to claim 1, wherein in step (1), the nanofiltration membrane has a molecular weight cut-off of 200-500 Da; the filtering pressure of the nanofiltration membrane is 0.2 Mpa-0.5 Mpa.

3. The method for separating ellagic acid from a byproduct of rubusoside production according to claim 1 or 2, wherein in step (1), the concentration of solids of the concentrate is 10% to 20%.

4. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 3, wherein in step (2), the inorganic acid is hydrochloric acid or sulfuric acid; the mass of the inorganic acid is 10-20% of the weight of the ellagitannin.

5. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 4, wherein in step (2), the temperature of hydrolysis is 98 to 140 ℃; the hydrolysis pressure is 0.05-0.5 MPa; the hydrolysis time is 1.0-2.0 hours.

6. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 5, wherein in step (3), the organic solvent is one or more of ethyl acetate, n-butanol, dichloromethane, and chloroform; the volume consumption of the organic solvent is 25-50 times (L/kg) of the weight of the ellagitannin.

7. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 6, wherein in step (4), the aqueous alkali solution is an aqueous solution of sodium hydroxide or potassium hydroxide; the mass percentage concentration of the alkaline water solution is 0.5-2%; the mass of the alkaline water solution is 20-30% of the dosage of the organic solvent.

8. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 7, wherein in step (5), the pH value is 1.5 to 2.5.

9. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 8, wherein in step (6), the volume fraction of ethanol in the ethanol aqueous solution is 80% to 99%; the volume consumption of the ethanol water solution is 8-12 times (L/kg) of the weight of the ellagic acid crude product.

10. The method for separating ellagic acid from a byproduct of rubusoside production according to any one of claims 1 to 9, wherein in step (6), the decolorizer is one or more of activated carbon, activated clay, diatomaceous earth and alumina; the mass of the decolorant is 1-5% of the weight of the crude ellagic acid product; the temperature for heat preservation and stirring is 70-80 ℃; and the stirring and decoloring time is 1-3 hours.

Technical Field

The invention relates to a method for separating ellagic acid, in particular to a method for separating ellagic acid from a byproduct of rubusoside production.

Background

Sweet tea (Rubus suavissimus S.Lee, English name sweet), also called Rubus suavissimus, is perennial spiny shrub of Rubus of Rosaceae, and was gradually discovered in China only in the early eighties of the twentieth century.

The sweet tea has sweet and fresh taste, can promote the production of body fluid to quench thirst, and has good pharmacological action and health-care function on human bodies. According to records of Chinese materia medica and reports of related documents: 'sweet tea' can prevent and cure hypertension, damp-heat dysentery, skin itch, carbuncle-abscess and malignant boil, and has the functions of nourishing liver and kidney, regulating stomach, lowering adverse qi, moistening lung, relieving cough, relieving sleepiness and sobering up. The compendium of materia Medica records: sweet and mild smell, no toxicity, hemorrhoid treatment, hemostasis, bloody dysentery, thirst quenching, blood circulation promoting and urination promoting.

Sweet tea is commonly used to replace cane sugar processed food, is used for tonifying kidney and reducing blood pressure by being taken as a medicine by the folk, is known as Shencha, is well known with fructus momordicae and the like. The rubusoside rich in rubus suavissimus is a diterpenoid glycoside, is similar to stevioside in chemical structure, and consists of the same aglycone, and the difference between the two is that one molecule of glucose is added to the ten-position carbon of the rubusoside less. The sweetness of the rubusoside is 300 times of that of the cane sugar, and the calorific value is only 5 percent of that of the cane sugar, so the rubusoside belongs to natural sweet substances with high sweetness and low calorie. The rubusoside can activate human insulin, synthesize blood sugar, and has good health promotion effect for patients with diabetes and kidney deficiency. The rubusoside extracted from the sweet tea leaves is the best taste in sweet plants, and shows good economic value in various industries such as food, beverage, cold food products, seasonings, the medical industry, beauty cosmetics and the like due to the green and natural sweet plants, health care and low heat.

The sweet tea polyphenol is one of important natural active ingredients in the sweet tea, and has biological activities of bacteriostasis, antioxidation, radiation protection, antianaphylaxis, cancer prevention and the like. Sweet tea produced in Guangxi contains sweet tea polyphenols more than 10% of the dry weight of the sweet tea. During the actual industrial production process of rubusoside, the rubuspolyphenol is leached out by water along with the rubusoside. Only the sweet tea polyphenol can not be enriched by the macroporous absorption resin, and the sweet tea glycoside can be enriched by the macroporous absorption resin. Due to the technical limitation and the bitter taste of sweet tea polyphenol, effluent liquid of the macroporous adsorption resin column containing a large amount of sweet tea polyphenol can only be used as waste and enters a sewage tank for environment-friendly treatment. Therefore, the burden of sewage treatment is increased, the natural active ingredient sweet tea polyphenol is wasted, and the comprehensive utilization of the natural resources of the sweet tea is not realized.

Ellagic acid is called gallic acid (benzoic acid) and has chemical formula C₁₄H₆O₈It is a polyphenol dilactone compound, which is a derivative formed by polymerizing two molecules of gallic acid. Ellagic acid is widely present in plant tissues of various fruits, vegetables, nuts, etc., and is a natural polyphenol component. Ellagic acid has various bioactive functions, such as antioxidant function, anticancer, antimutagenic property, and inhibitory effect on human immunodeficiency virus. In addition, ellagic acid is an effective coagulant, has good inhibitory effect on various bacteria and viruses, and can protect wound surface from invasion of bacteria, prevent infection, and inhibit ulcer. The research shows that the ellagic acid also has the effects of lowering blood pressure and tranquilizing. Ellagic acid shows obvious inhibiting effect on canceration induced by chemical substances and other multiple canceration, and especially has good inhibiting effect on colon cancer, esophageal cancer, liver cancer, lung cancer, tongue and skin tumor, etc.

Ellagic acid is found not only in free form but also in more condensed form (e.g. ellagitannins, etc.) in nature. Sweet tea polyphenols is a mixture, and the main ingredient is ellagitannin. How to recycle sweet tea polyphenol treated as waste at present and process the sweet tea polyphenol into ellagic acid with more economic value needs to be solved urgently.

CN110078775B discloses an environment-friendly production method of high-content rubusoside and rubuspolyphenol, which is characterized in that dried rubusoside is used as a raw material, and the high-content rubusoside and rubuspolyphenol are respectively obtained through the steps of crushing, percolation extraction, flocculation, centrifugation, desalination, decoloration, macroporous resin adsorption, gradient elution, flocculation acidification, organic solvent extraction and the like.

CN108752392B discloses a method for recovering rubus suavissimus polyphenol from rubus suavissimus flocculation residues after rubus suavissimus glycoside extraction, which is to use rubus suavissimus flocculation residues after rubus suavissimus glycoside extraction as raw materials, and obtain rubus suavissimus through acid dissolution, macroporous adsorption resin enrichment, alumina refining and other steps.

CN108752231A discloses a method for extracting theanine and simultaneously extracting rubusoside and tea polyphenol from sweet tea, which is to obtain theanine, rubusoside and tea polyphenol from sweet tea leaves by the steps of crushing, percolating, macroporous adsorption resin adsorption, polyamide resin column adsorption, ion exchange resin column adsorption and the like.

CN101993460A discloses a method for separating and purifying ellagitannic acid in Rubus corchorifolius, which is to take dry leaves of Rubus corchorifolius as raw materials, and obtain the ellagitannic acid by water extraction, macroporous adsorption resin column chromatography, separation of an outflow mother liquor ultrafiltration membrane, drying and supercritical carbon dioxide extraction.

However, in the prior art, the research on sweet tea polyphenol mainly aims at the separation of sweet tea total polyphenol (mixture) or ellagitannic acid, and no report of the separation of ellagitannic acid from sweet tea raw material or from a sweet tea glycoside production byproduct is found.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects in the prior art and provide a method for separating ellagic acid from byproducts in rubusoside production, which comprehensively utilizes sweet tea resources, changes waste into valuable, has high yield, high content of effective active ingredients in products, strong operability of technological process, low requirements on equipment, low production cost, safety, environmental protection and suitability for industrial production.

The technical scheme adopted for solving the technical problem is that the method for separating the ellagic acid from the byproducts of the rubusoside production comprises the following steps:

(1) collecting and concentrating the effluent of the sweet tea column: collecting the column-loading effluent of the macroporous adsorbent resin column in the rubusoside production process, filtering with a nanofiltration membrane, and concentrating the nanofiltration membrane retentate to obtain rubusoside concentrate;

(2) pressurized hydrolysis: adding inorganic acid into the sweet tea polyphenol concentrated solution obtained in the step (1), pressurizing, and carrying out thermal insulation hydrolysis to obtain a hydrolyzed material;

(3) organic solvent extraction: cooling the hydrolyzed material obtained in the step (2) to room temperature, then extracting with an organic solvent, separating liquid, and collecting an organic solvent layer;

(4) back extraction with alkaline water: carrying out back extraction on the organic solvent layer obtained in the step (3) by using an aqueous alkali solution, separating liquid, and collecting an aqueous alkali layer;

(5) acidifying: adjusting the pH value of the alkaline water layer obtained in the step (4) to acidity by using hydrochloric acid, separating out solid, filtering the solid, and drying to obtain a crude ellagic acid product;

(6) and (3) crystallization: and (3) heating and dissolving the ellagic acid crude product obtained in the step (5) by using an ethanol water solution, adding a decoloring agent, keeping the temperature, stirring and decoloring, filtering while hot, freezing and crystallizing, filtering crystals, and drying to obtain an ellagic acid product.

Preferably, in the step (1), the effluent liquid from the column is industrial wastewater generated after the sweet tea raw material is subjected to the process steps of water extraction, centrifugal filtration, column adsorption on macroporous adsorption resin and the like. The mass percentage content of the total solid in the column-loading effluent is 0.5-10%, the mass percentage content of the sweet tea polyphenol in the total solid is 30-50%, and the mass percentage content of the ellagitannin in the total solid is 15-30%.

Preferably, in the step (1), the molecular weight cut-off of the nanofiltration membrane is 200-500 Da, and more preferably 300-400 Da; the filtering pressure of the nanofiltration membrane is 0.2 to 0.5Mpa, and more preferably 0.3 to 0.4 Mpa.

One of the purposes of using the nanofiltration membrane is to remove inorganic salts in the effluent liquid of the upper column, because the existence of divalent metal cations such as calcium, magnesium, iron, copper and the like can not only reduce the activity of tannase, but also complex ellagic acid which is a hydrolysis product to form a complex with stable properties, thereby reducing the yield of the ellagic acid; the second purpose of using the nanofiltration membrane is to remove small molecular impurities such as amino acid, pigment and the like so as to improve the purity of the ellagitannin, thereby reducing the difficulty of the subsequent separation and purification steps. If the molecular weight cut-off of the nanofiltration membrane is too low or the filtering pressure is too low, inorganic salts and small molecular impurities cannot penetrate through the nanofiltration membrane to be removed, so that the two purposes cannot be achieved; if the molecular weight cut-off of the nanofiltration membrane is too high or the filtration pressure is too high, part of ellagitannins may penetrate through the nanofiltration membrane and be lost, so that the yield of ellagic acid is low. The third purpose of using the nanofiltration membrane is to concentrate the materials by adopting a low-temperature and energy-saving mode, so that the oxidation and the condensation of the ellagitannin with impurities at high temperature can be avoided, the concentration of the ellagitannin can be improved, the using amount of inorganic acid can be saved, and the hydrolysis speed can be accelerated.

Preferably, in the step (1), the concentration of the solid content of the concentrated solution is 10 to 20%, more preferably 12 to 15%.

The purpose of concentrating the nanofiltration membrane trapped liquid membrane to the concentration is to improve the concentration of ellagitannin so as to reduce the treatment amount of subsequent materials and save the use amount of inorganic acid. If the concentration of the solid matters in the concentrated solution is too low, the dosage of acid is increased or the hydrolysis time is prolonged; if the concentration of the solid matter in the concentrated solution is too high, the solubility of ellagitannins is reduced, and the hydrolysis efficiency is reduced.

Preferably, in step (2), the inorganic acid is hydrochloric acid or sulfuric acid; the mass of the inorganic acid is 10-20% of the weight of the ellagitannin, and is more preferably 11-18%.

One of the purposes of adding inorganic acid into the sweet tea polyphenol concentrated solution is to hydrolyze ellagitannin in the sweet tea polyphenol concentrated solution into target product ellagitannin; the second purpose is that macromolecular impurities (such as polysaccharide, protein and the like) in the concentrated solution are hydrolyzed into small molecules and are easily removed through the subsequent extraction-back extraction steps.

Preferably, in the step (2), the hydrolysis temperature is 98-140 ℃, and more preferably 110-130 ℃; the hydrolysis pressure is 0.05-0.5 MPa, and more preferably 0.1-0.35 MPa; the hydrolysis time is 1.0-2.0 hours.

The invention adopts pressurized hydrolysis to reduce the dosage of acid and shorten the hydrolysis time. If the hydrolysis temperature is too low, the pressure is too low or the time is too short, the incomplete hydrolysis can be caused; if the hydrolysis temperature is too high, the pressure is too high or the time is too long, energy and materials are wasted.

Preferably, in the step (3), the organic solvent is one or more of ethyl acetate, n-butanol, dichloromethane and chloroform; the volume dosage of the organic solvent is 25-50 times (L/kg) of the weight of the ellagitannin, and is preferably 30-40 times (L/kg). The purpose of using organic solvent for extraction is to transfer the ellagic acid obtained after hydrolysis from the water phase to the organic phase, so as to achieve the purpose of primary separation and purification.

Preferably, in the step (4), the aqueous alkali solution is an aqueous solution of sodium hydroxide or potassium hydroxide; the concentration of the alkaline water solution is 0.5 to 2 percent by mass, and more preferably 1 to 1.5 percent by mass; the mass of the alkaline water solution is 20-30% of the dosage of the organic solvent.

The purpose of back extraction by using alkaline water is to react ellagic acid in the organic layer with alkali to form salt, and dissolve the salt in the alkaline water to achieve the purpose of separating and purifying again. If the mass percentage of the alkali water solution is too low or the dosage of the alkali water is too small, the purpose can not be fully achieved, and the yield of the ellagic acid is low; if the mass percentage of the aqueous alkali solution is too high or the dosage of the aqueous alkali is too much, not only energy and material waste is caused, but also the ellagic acid is decomposed and destroyed, and the yield of the ellagic acid is also low.

Preferably, in the step (5), the pH value is 1.5-2.5. The purpose of adjusting the pH of the alkaline aqueous layer to acidic with hydrochloric acid is to convert the ionic ellagic acid salt dissolved in the alkaline aqueous layer into molecular ellagic acid, thereby crystallizing out.

Preferably, in the step (6), the volume fraction of ethanol in the ethanol aqueous solution is 80-99%; the volume consumption of the ethanol water solution is 8-12 times (L/kg) of the weight of the ellagic acid crude product.

Preferably, in the step (6), the decolorizing agent is one or more of activated carbon, activated clay, diatomite and alumina; the mass of the decolorant is 1-5% of the weight of the crude ellagic acid product, and more preferably 2-4%; the temperature for heat preservation and stirring is 70-80 ℃; the stirring and decoloring time is 1-3 hours, and more preferably 2-3 hours. The purpose of stirring and decoloring by using a decoloring agent is to remove pigments and impurities in the ethanol solution of the crude ellagic acid product, thereby obtaining a refined ellagic acid product with high content.

Preferably, in the step (6), the temperature of freezing crystallization is-10 to 10 ℃, and more preferably-5 to 5 ℃; the time for freezing crystallization is 12-24 hours, and more preferably 16-22 hours. The purpose of freeze crystallization is to sufficiently precipitate ellagic acid in an ethanol solution and ensure the yield of ellagic acid.

The principle of the invention is as follows: the effluent liquid of the macroporous adsorption resin column in the rubusoside production process is rich in ellagitannin, and the ellagitannin is decomposed into ellagic acid under the action of pressurization and acid hydrolysis; hydrolysate of other macromolecular substances (saccharides, amino acids and the like) in the hydrolysate cannot be extracted by the organic solvent, and the ellagic acid can be extracted by the organic solvent, so that the ellagic acid can be primarily separated and purified by the organic solvent extraction mode. Even if a small amount of fat-soluble impurities are extracted together with ellagic acid by the organic solvent, these fat-soluble impurities can be retained in the organic solvent layer by the back-extraction with alkaline water; the ellagic acid salt in the alkaline water layer can be recovered to molecular state by acidification, and can be precipitated.

Compared with the prior art, the invention has the following beneficial technical effects:

(1) the content of the ellagic acid in the ellagic acid product obtained by the invention is as high as more than 97%;

(2) the method has the advantages of less acid consumption, less waste acid discharge and less sewage treatment burden in the pressurized hydrolysis process;

(3) the invention can comprehensively utilize sweet tea resources, and the method for separating the ellagic acid from the byproducts of the sweet tea glycoside production changes waste into valuable, has strong operability of the process, low requirements on equipment, low production cost, safety, environmental protection and suitability for industrial production.

Detailed Description

The present invention will be further described with reference to the following examples.

The effluent liquid of the upper column of the macroporous adsorption resin column in the rubusoside production process used in the embodiment of the invention is a byproduct waste material generated in the rubusoside production process of Hunan Huacheng biological resource GmbH, and the mass percentage contents of the total solid, the rubusoside, the ellagitannin and the ellagic acid are 2.05%, 0.72%, 0.43% and 0% in sequence through analysis; the starting materials or chemicals used in the examples of the present invention are, unless otherwise specified, commercially available in a conventional manner.

In the embodiment of the invention, the content of sweet tea polyphenol is measured by adopting an ultraviolet spectrophotometry method, the content of ellagic acid is detected by adopting a High Performance Liquid Chromatography (HPLC) external standard method, and the manufacturers and models of the used ultraviolet spectrophotometer and high performance liquid chromatograph are respectively Beijing Pujing analytical instruments, Inc. TU-1900 and Shimadzu LC-2030 Plus.

Example 1

The embodiment comprises the following specific steps:

(1) collecting and concentrating the effluent of the sweet tea column: collecting 1 ton of column-loaded effluent of a macroporous adsorption resin column in the rubusoside production process, filtering with a nanofiltration membrane (the cut-off molecular weight of the nanofiltration membrane is 500Da, and the filtering pressure is 0.2 Mpa), and concentrating the nanofiltration membrane cut-off liquid to a solid concentration of 12.5% with the nanofiltration membrane to obtain 120L rubusoside concentrated solution;

(2) pressurized hydrolysis: adding 0.8kg of concentrated hydrochloric acid into the sweet tea polyphenol concentrated solution obtained in the step (1), pressurizing to 0.2MPa, and carrying out heat preservation and hydrolysis at 115 ℃ for 1.2 hours to obtain a hydrolyzed material;

(3) organic solvent extraction: cooling the hydrolyzed material obtained in the step (2) to room temperature, extracting with 120L ethyl acetate, separating liquid, and collecting an organic solvent layer;

(4) back extraction with alkaline water: carrying out back extraction on the organic solvent layer obtained in the step (3) by using 30L of a sodium hydroxide aqueous solution with the mass percentage concentration of 2%, separating liquid, and collecting an alkaline water layer;

(5) acidifying: adjusting the pH value of the alkaline water layer obtained in the step (4) to 2.0 by using hydrochloric acid, separating out a large amount of solid, filtering, placing the filter cake in an air drying oven at 80 ℃, and drying to constant weight to obtain 1.37kg of crude ellagic acid;

(6) and (3) crystallization: and (3) heating and dissolving the ellagic acid crude product obtained in the step (5) by using 15L of ethanol with the volume fraction of 90%, adding 0.04kg of alumina, keeping the temperature at 80 ℃, stirring and decoloring for 2 hours, filtering while hot, freezing the filtrate to 5 ℃, crystallizing for 24 hours, filtering the crystals, and drying to obtain 1.14kg of ellagic acid product.

Through detection of a high performance liquid chromatography external standard method, the content of ellagic acid in the ellagic acid crude product obtained in the embodiment of the invention is 91.26%, and the content of ellagic acid in the ellagic acid product obtained in the embodiment of the invention is 98.55%.

Example 2

The embodiment comprises the following specific steps:

(1) collecting and concentrating the effluent of the sweet tea column: collecting 1 ton of column-loaded effluent of a macroporous adsorption resin column in the rubusoside production process, filtering with a nanofiltration membrane (the cut-off molecular weight of the nanofiltration membrane is 200Da, and the filtering pressure is 0.4 Mpa), and concentrating the nanofiltration membrane cut-off liquid to a solid concentration of 12.1% with the nanofiltration membrane to obtain 124L rubusoside concentrated solution;

(2) pressurized hydrolysis: adding 0.6kg of concentrated hydrochloric acid into the sweet tea polyphenol concentrated solution obtained in the step (1), pressurizing to 0.35MPa, and carrying out heat preservation and hydrolysis at 130 ℃ for 2.0 hours to obtain a hydrolyzed material;

(3) organic solvent extraction: cooling the hydrolyzed material obtained in the step (2) to room temperature, extracting with 130L of chloroform, separating liquid, and collecting an organic solvent layer;

(4) back extraction with alkaline water: carrying out back extraction on the organic solvent layer obtained in the step (3) by using 36L of potassium hydroxide aqueous solution with the mass percentage concentration of 1.5%, separating liquid, and collecting an alkaline water layer;

(5) acidifying: adjusting the pH value of the alkaline water layer obtained in the step (4) to 1.5 by using hydrochloric acid, separating out a large amount of solid, filtering, placing the filter cake in an air drying oven at 80 ℃, and drying to constant weight to obtain 1.40kg of crude ellagic acid;

(6) and (3) crystallization: and (3) heating and dissolving the crude ellagic acid product obtained in the step (5) by using 13L of ethanol with the volume fraction of 95%, adding 0.05kg of diatomite, keeping the temperature at 75 ℃, stirring and decoloring for 3 hours, filtering while hot, freezing the filtrate to-2 ℃, crystallizing for 16 hours, filtering the crystals, and drying to obtain 1.17kg of ellagic acid product.

The content of ellagic acid in the crude ellagic acid product obtained in the embodiment of the invention is 90.19% and the content of ellagic acid in the ellagic acid product obtained in the embodiment of the invention is 97.93% through detection of a high performance liquid chromatography external standard method.

Example 3

The embodiment comprises the following specific steps:

(1) collecting and concentrating the effluent of the sweet tea column: collecting 1 ton of effluent liquid on a macroporous adsorption resin column in the rubusoside production process, filtering with a nanofiltration membrane (the cut-off molecular weight of the nanofiltration membrane is 300Da, and the filtering pressure is 0.3 Mpa), and concentrating the nanofiltration membrane cut-off liquid to a solid concentration of 14.1% by using the nanofiltration membrane to obtain 106.5L rubusoside concentrated solution;

(2) pressurized hydrolysis: adding 0.5kg of concentrated sulfuric acid into the sweet tea polyphenol concentrated solution obtained in the step (1), pressurizing to 0.1MPa, and carrying out heat preservation and hydrolysis at 108 ℃ for 1.5 hours to obtain a hydrolyzed material;

(3) organic solvent extraction: cooling the hydrolyzed material obtained in the step (2) to room temperature, extracting with 160L dichloromethane, separating liquid, and collecting an organic solvent layer;

(4) back extraction with alkaline water: carrying out back extraction on the organic solvent layer obtained in the step (3) by using 38L of a sodium hydroxide aqueous solution with the mass percentage concentration of 1.4%, separating liquid, and collecting an alkaline water layer;

(5) acidifying: adjusting the pH value of the alkaline water layer obtained in the step (4) to 2.0 by using hydrochloric acid, separating out a large amount of solid, filtering, placing the filter cake in an air drying oven at 80 ℃, and drying to constant weight to obtain 1.41kg of crude ellagic acid;

(6) and (3) crystallization: and (3) heating and dissolving the crude ellagic acid product obtained in the step (5) by using 14L of ethanol with the volume fraction of 85%, adding 0.05kg of activated carbon, keeping the temperature at 80 ℃, stirring and decoloring for 3 hours, filtering while hot, freezing the filtrate to 0 ℃, crystallizing for 18 hours, filtering the crystals, and drying to obtain 1.15kg of ellagic acid product.

The content of ellagic acid in the crude ellagic acid product obtained in the embodiment of the invention is 89.92% and the content of ellagic acid in the ellagic acid product obtained in the embodiment of the invention is 97.28% through detection of a high performance liquid chromatography external standard method.