A method for extracting ginsenoside from ginseng residue and utilizing the residue after extraction

Abstract

The invention discloses a method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction. The method uses discarded ginseng residue as raw material, uses a low eutectic solvent of choline chloride / propionic acid, ethylene glycol or diethylene glycol and water to form an extraction solvent to extract the ginseng residue, collects the extract to obtain ginsenosides, ginseng polysaccharides and other effective components, and the residue after extraction is prepared into ginseng residue dietary fiber. The method of the invention has a high extraction rate of total ginsenosides, mild reaction conditions and a short extraction time; the extraction process also increases the surface area of ​​ginseng residue dietary fiber, which is conducive to the adsorption of intestinal harmful substances and has a high nutritional value. The method improves the utilization value of ginseng residue and is easy to promote industrialization.

Description

Technical Field

[0001] The invention relates to a method for extracting ginsenoside from ginseng residue and high-value utilization of the residue after extraction, belonging to the technical field of waste biomass resource utilization. Technical Background

[0002] Ginseng is a perennial herbaceous plant of the Araliaceae family and the genus Panax. It is widely distributed in China, Russia and North Korea; in China, it is mainly distributed in the eastern part of Liaoning, the eastern half of Jilin and the eastern part of Heilongjiang. The fleshy root of ginseng is a tonic medicine, suitable for adjusting blood pressure, restoring heart function, neurasthenia and physical weakness, and also has the effects of expectoration, stomachic, diuresis and excitement. The stems, leaves, flowers, fruits and processing by-products of ginseng are all raw materials for light industry, and can be processed into products such as tobacco, wine, tea, crystals and pastes containing ginseng ingredients. Ginseng contains ginsenosides, ginseng polysaccharides, amino acids, volatile oils, vitamins, alkaloids, organic acids and other ingredients, among which ginsenosides are considered to be the most representative active ingredients of ginseng. my country consumes more than 70,000 tons of ginseng medicinal materials every year, most of which are used to extract ginsenosides. Since the content of ginsenosides in ginseng roots is only 4%, most of the ginseng medicinal materials are converted into ginseng residues. The discarded ginseng residues are generally used as feed or discarded at will, with low utilization value and easy to pollute the environment.

[0003] After analyzing the ginseng residue, it was found that its main components are ginseng dietary fiber (cellulose, hemicellulose, lignin and pectin, etc.), and it also contains ginsenosides, ginseng polysaccharides, amino acids, volatile oils, vitamins, alkaloids, organic acids and other chemically active substances. Ginseng polysaccharides account for about 8% to 10% of the dry weight of ginseng residue, and have the functions of enhancing immunity, promoting hematopoiesis, lowering blood sugar, anti-diuresis, anti-aging, anti-thrombosis, anti-bacterial, anti-inflammatory, and anti-tumor. Ginseng dietary fiber has the effects of lowering blood lipids and blood sugar, promoting gastrointestinal motility, and preventing and treating constipation. If this part of the resources can be used reasonably, it can not only increase the rational utilization of ginseng residue resources, but also reduce its pollution to the environment, and drive the development of other agricultural projects in the planting area.

[0004] The literature reports on the utilization of ginseng residue are mostly for preparing feed and fermenting to produce sugar, and there are relatively few reports on its comprehensive utilization.

[0005] The patent with publication number CN 111184212A reports a method for preparing ginseng polysaccharide tablets, which uses ginseng residue after ginsenoside extraction as the main raw material, and prepares ginseng polysaccharide tablets through crushing, granulation and tableting steps, and the ginseng residue content is 95% to 98.5%. The process is cumbersome and time-consuming, and the industrial utilization effect is poor. In addition, the ginseng polysaccharide content is low, and the product value is not high.

[0006] The patent with publication number CN 110150678A reports a ginseng dietary fiber chewable tablet and its preparation method. Ginseng residue is used as raw material, the ginseng residue is rinsed, dried, crushed, soaked in water, and centrifuged to obtain ginseng dietary fiber powder; then mixed with auxiliary materials, granulated, and tableted to obtain ginseng dietary fiber chewable tablets. The preparation process of this method is complicated, and the ginsenosides and ginseng polysaccharides in the ginseng residue are not recycled, resulting in energy waste.

[0007] The patent with publication number CN 110922442A reports a green method for preparing ginseng extracts rich in rare ginsenosides Rg3 and Rg5. The method uses the roots of Panax plants as raw materials and the fruit acid in fruit juice as a structural modifier. Through a one-step operation, the efficient extraction of ginsenosides, the structural modification of ginsenosides, the solid-liquid separation of ginseng extracts and ginseng residues, and the concentration of ginseng extracts are integrated to prepare ginseng extracts rich in rare ginsenosides Rg3 and Rg5. Although the method has high extraction efficiency, the reaction conditions are relatively high, and the residue after extraction is not utilized.

[0008] It can be seen that among the existing methods for resource utilization of ginseng residue, most focus on the utilization of a single component, and there is still a lack of effective utilization methods for the most valuable ginsenosides. In addition, there is no comprehensive consideration of the utilization of the residue, and the process operation is cumbersome and the yield is low, resulting in serious waste of resources and bringing pressure to the environment.

[0009] Deep eutectic solvent (DES) is a green solvent discovered by Abbott et al. in recent years that can replace traditional organic solvents and ionic liquids. It refers to a two-component or three-component eutectic mixture composed of a certain stoichiometric ratio of hydrogen bond acceptors (such as quaternary ammonium salts) and hydrogen bond donors (such as compounds such as amides, carboxylic acids and polyols). Its freezing point is significantly lower than the melting point of the pure substances of each component. The synthetic components of DESs are mostly natural products, cheap and biodegradable. The preparation process is also very simple. Just mix the corresponding components together in a set ratio and stir at low temperature to obtain a eutectic mixed liquid solvent. The low cost, designability, biodegradability and environmental friendliness of DESs make them a universal substitute for traditional organic solvents. Summary of the invention

[0010] In order to realize the high-value utilization of ginseng residue, the present invention provides a method for extracting ginsenosides from ginseng residue and comprehensively utilizing the residue after extraction, which can quickly and efficiently extract the active ingredients in the ginseng residue, and the residue after extraction is further prepared into ginseng residue dietary fiber, thereby realizing the high-value utilization of ginseng residue and facilitating industrial promotion.

[0011] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0012] A method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction, characterized in that the method comprises the following steps:

[0013] 1) mixing choline chloride, propionic acid, ethylene glycol or diethylene glycol, and stirring at room temperature until a homogeneous transparent liquid is obtained to prepare a deep eutectic solvent;

[0014] 2) adding an extraction solvent consisting of the low eutectic solvent in step 1) and water to the crushed ginseng residue, extracting, filtering and collecting the extract to obtain a ginseng residue extract and a solid residue;

[0015] 3) After the extract in step 2) is concentrated, ethanol is added for precipitation, and centrifugation is performed to obtain a crude ginseng polysaccharide solid and a ginsenoside extract;

[0016] 4) The solid residue extracted in step 2) is washed with pure water until neutral, soaked in water, centrifuged, dried, and crushed to obtain ginseng residue dietary fiber.

[0017] In the method, in step 1), a low eutectic solvent composed of choline chloride and propionic acid is preferred.

[0018] In the method, the molar ratio of choline chloride to propionic acid, ethylene glycol or diethylene glycol in the low eutectic solvent of step 1) is preferably 1:3 to 1:5, and the most preferred molar ratio is 1:3.

[0019] In the method, in the extraction solvent of step 2), the volume percentage of the low eutectic solvent is 50-90%, and the preferred volume percentage is 70%.

[0020] In the method, in step 2), the solid-liquid ratio of ginseng residue to extraction solvent is 1:15-35 (g / mL), preferably 1:20-25 (g / mL).

[0021] In the method described above, the extraction time in step 2) is preferably 20 to 40 minutes.

[0022] In the method, preferably, ultrasound-assisted extraction is used in step 2).

[0023] In the method, the amount of ethanol added in step 3) is 3 to 4 times the volume of the extract.

[0024] In the method, the alcohol precipitation time in step 3) is 12 to 24 hours.

[0025] In the method, the mass ratio of the solid residue to water in step 4) is 1:20 to 1:30.

[0026] In the method, the soaking time in step 4) is 10 to 16 hours.

[0027] Beneficial effects of the present invention: The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction uses discarded ginseng residue as raw material, extracts ginsenosides and ginseng polysaccharides through a low eutectic solvent, and prepares ginseng residue dietary fiber from the residue after extraction, thereby improving the utilization value of ginseng residue and facilitating industrial promotion.

[0028] 1) The present invention utilizes green low eutectic solvents such as choline chloride / propionic acid to extract ginseng residue to obtain an extract containing ginsenosides and ginseng polysaccharides. Compared with traditional organic solvent extraction, ginsenosides can be extracted from ginseng residue and a higher ginsenoside extraction rate can be achieved. The extraction conditions are milder and the time required is shorter. It has the advantages of energy saving, high efficiency, safety and environmental protection.

[0029] 2) After the low eutectic solvent extraction, the extract is precipitated with ethanol to obtain ginsenoside extract and ginseng polysaccharide, without the need for additional extraction steps, which greatly simplifies the process flow and has the advantages of being economical and simple.

[0030] 3) After extracting ginsenosides and ginseng polysaccharides, the solid residue is simply rinsed, soaked, and dried to further obtain ginseng residue dietary fiber, which increases the surface area of ​​the ginseng residue dietary fiber, is conducive to the adsorption of intestinal harmful substances, and has a higher nutritional value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Process flow chart of extracting ginsenosides from ginseng residue and utilizing the residue after extraction;

[0032] Figure 2 Surface scanning electron microscopy images of ginseng residue before (a) and after (b) extraction;

[0033] Figure 3 Effect of extraction solvent on the extraction of total ginsenosides from ginseng residue;

[0034] Figure 4 Effect of molar ratio on the extraction of total ginsenosides from ginseng residue;

[0035] Figure 5 Effect of moisture content on the extraction of total ginsenosides from ginseng residue;

[0036] Figure 6 Effect of solid-liquid ratio on the extraction of total ginsenosides from ginseng residue;

[0037] Figure 7 Effect of time on the extraction of total ginsenosides from ginseng residue;

[0038] Figure 8 Antioxidant properties of ginseng polysaccharides; a-hydroxyl radical scavenging ability, b-DPPH scavenging ability. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described in detail below through specific embodiments. However, it is necessary to point out that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of the present invention.

[0040] Example 1

[0041] A method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction, comprising the following steps:

[0042] (1) Choline chloride and propionic acid are mixed in a molar ratio of 1:3, and stirred at room temperature for 30 minutes to form a uniform transparent liquid, thereby preparing a low eutectic solvent.

[0043] (2) A certain amount of (absolutely dry) ginseng residue is taken, crushed and passed through an 80-mesh sieve, and then placed in a container. A mixture of a low eutectic solvent and water is added at a solid-liquid ratio of 1:20 g / mL, wherein the mixture contains 70% (volume fraction) of the low eutectic solvent; the mixture is added for extraction in 1-3 times, and each time the extraction is performed in the container by ultrasonic extraction for 30 minutes, centrifuged, and the extract and solid residue are collected.

[0044] The total content of ginsenosides in the extract was determined by the vanillin-glacial acetic acid-concentrated sulfuric acid ultraviolet colorimetric method, and the ginsenoside extraction rate was 36.7 mg / g (absolutely dry ginseng residue).

[0045] (3) The supernatant is concentrated to a certain volume by rotary evaporation under reduced pressure. The concentrated extract is precipitated with ethanol at a volume ratio of 1:4 for 12 hours, and then centrifuged. The filtrate is the ginsenoside extract, and the crude ginseng polysaccharide is precipitated and dried and ground into powder.

[0046] (4) The solid residue after extraction in step (2) is washed with pure water until neutral, mixed with water (mass ratio is 1:20) to form a mixed solution, soaked for 12 hours, centrifuged, and the precipitate is taken, dried and crushed to obtain ginseng residue dietary fiber.

[0047] The process flow of the method is shown in Figure 1 . The surface scanning electron microscopy images of ginseng residue before and after extraction are as follows Figure 2 , the microstructure of the surface of ginseng residue after extraction is looser, with more cracks and pores. The possible reason is that a large amount of soluble substances are removed from the ginseng residue during the extraction process, resulting in the destruction of part of the structure of ginseng fiber. After extraction treatment, ginseng residue shows a relatively regular loose structure and cavities. The extraction treatment makes the structure of ginseng residue looser, increases the specific surface area, and improves its absorption capacity for water, oil, heavy metals and salt ions. Overall, there is no obvious difference in the microstructure of ginseng residue before and after extraction, and it is still mainly composed of insoluble cellulose.

[0048] Example 2 Effect of different solvents on the extraction of ginsenosides from ginseng residue

[0049] Choline chloride was mixed with acetic acid, glycolic acid, lactic acid, propionic acid, glycerol, ethylene glycol, diethylene glycol, and 1,4-butanediol at a molar ratio of 1:2, and stirred at room temperature for 30 minutes to form a uniform and transparent liquid to prepare a group of low eutectic solvents. A certain amount of (absolutely dry) ginseng residue was taken, crushed through an 80-mesh sieve, and placed in a container. A mixture of 80% (volume percentage) of different low eutectic solvents and 20% water, as well as ethanol were added as extraction solvents, with a solid-liquid ratio of 1:20. Ultrasonic extraction was performed for 30 minutes, and the extraction was performed three times. The extract was filtered and the extract and solid residue were collected. The ginsenoside extraction rates of different extraction solvents composed of each low eutectic solvent are as follows: Figure 3 .

[0050] When the low eutectic solvent system is choline chloride / propionic acid, the extraction effect of ginsenosides in ginseng residue is the best, and the extraction rate is 22.7 mg / g. Compared with the traditional solvent ethanol (11.5 mg / g), the extraction rate is significantly improved.

[0051] Example 3 Effect of molar ratio in deep eutectic solvent on extraction of ginsenosides from ginseng residue

[0052] Choline chloride and propionic acid were mixed in a molar ratio of 1:2, 1:3, 1:4, 1:5, and 1:6, respectively, and stirred at room temperature for 30 minutes to form a uniform transparent liquid to prepare a group of low eutectic solvents. Take a certain amount of (absolutely dry) ginseng residue, crush it through an 80-mesh sieve, and place it in a container. Add 80% (volume percentage) of a low eutectic solvent and 20% water in a mixed solution, with a solid-liquid ratio of 1:20, and ultrasonically extract for 30 minutes. Extract three times, filter, and collect the extract and solid residue. The extraction rate of ginsenosides of low eutectic solvents with different molar ratios is as follows Figure 4 .

[0053] When the molar ratio of choline chloride to propionic acid was 1:3-1:5, the extraction rate of total ginsenosides exceeded 25 mg / g. When the molar ratio of choline chloride to propionic acid was 1:3, the extraction effect was the best, and the extraction rate of ginsenosides was 31.7 mg / g.

[0054] Example 4 Effect of water content of extraction solvent on extraction of ginsenosides from ginseng residue

[0055] Choline chloride and propionic acid were mixed in a molar ratio of 1:3, stirred at room temperature for 30 minutes to form a uniform transparent liquid, and a low eutectic solvent was prepared. Take a certain amount of (absolutely dry) licorice residue, crush it through an 80-mesh sieve and place it in a container, add 50%, 60%, 70%, 80%, 90% (volume percentage) of a mixture of a low eutectic solvent and water, respectively, with a solid-liquid ratio of 1:20, ultrasonically extract for 30 minutes, extract three times, filter, and collect the extract and solid residue. The extraction rate of ginsenosides in extraction solvents with different water contents is as follows Figure 5 .

[0056] Extraction solvents with a water content of 10%-50% can effectively extract ginsenosides from ginseng residue. When the volume percentage of the low eutectic solvent is 70%, the best extraction rate of total ginsenosides is 33 mg / g.

[0057] Example 5 Effect of the solid-liquid ratio on the extraction of ginsenosides from ginseng residue

[0058] Choline chloride and propionic acid were mixed at a molar ratio of 1:3, stirred at room temperature for 30 minutes to form a uniform transparent liquid, and a low eutectic solvent was prepared. Take a certain amount of (absolutely dry) ginseng residue, crush it through an 80-mesh sieve and place it in a container, and add extraction solvents at a solid-liquid ratio of 1:15, 1:20, 1:25, 1:30, and 1:35, respectively. The extraction solvent is a mixture of 70% (volume percentage) of the low eutectic solvent and water. Ultrasonic extraction was performed for 30 minutes, and the extraction was performed three times. The extract was filtered and the extract and solid residue were collected. The extraction rate of ginsenosides at different solid-liquid ratios is as follows. Figure 6 .

[0059] The solid-liquid ratio of 1:15-35g / mL can effectively extract ginsenosides from ginseng residue. The solid-liquid ratio of 1:20-25g / mL has a higher ginsenoside extraction rate, and the optimal extraction solid-liquid ratio is 1:20, with a ginsenoside extraction rate of 34.7mg / g.

[0060] Example 6 Effect of extraction time on ginsenoside extraction from ginseng residue

[0061] Choline chloride and propionic acid were mixed in a molar ratio of 1:3, stirred at room temperature for 30 minutes to form a uniform transparent liquid, and a low eutectic solvent was prepared. A certain amount of (absolutely dry) ginseng residue was taken, crushed through an 80-mesh sieve and placed in a container, and a mixture of 70% (volume percentage) of a low eutectic solvent and water was added in a solid-liquid ratio of 1:20. Ultrasonic extraction was performed in the container for 10 minutes, 20 minutes, 30 minutes, 40 minutes, and 50 minutes, respectively. The extraction was divided into 3 times, filtered, and the extract and solid residue were collected. The extraction rate of ginsenosides is as follows: Figure 7 .

[0062] Ginsenosides can be effectively extracted from ginseng residues under the conditions of 20-40min extraction. The optimal extraction time of ginsenosides is 30min, and the extraction rate is 34.7mg / g.

[0063] Example 7

[0064] A method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction, comprising the following steps:

[0065] (1) Choline chloride and ethylene glycol are mixed in a molar ratio of 1:3, and stirred at room temperature for 30 minutes to form a uniform transparent liquid, thereby preparing a low eutectic solvent.

[0066] (2) A certain amount of (absolutely dry) ginseng residue is taken, crushed and passed through an 80-mesh sieve, and then placed in a container. A mixture of a low eutectic solvent and water is added at a solid-liquid ratio of 1:20 g / mL, wherein the mixture contains 70% (volume fraction) of the low eutectic solvent; ultrasonic extraction is performed in the container for 30 minutes, and the mixture is centrifuged to collect the extract and the solid residue.

[0067] (3) The supernatant is concentrated to a certain volume by rotary evaporation under reduced pressure. The concentrated extract is precipitated with ethanol at a volume ratio of 1:4 for 16 hours, and then centrifuged. The filtrate is the ginsenoside extract, and the crude ginseng polysaccharide is precipitated and dried and ground into powder.

[0068] (4) The solid residue after extraction in step (2) is washed with pure water until neutral, mixed with water (mass ratio is 1:30) to form a mixed solution, soaked for 10 hours, centrifuged, and the precipitate is taken and dried to obtain ginseng residue dietary fiber.

[0069] Example 8

[0070] A method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction, comprising the following steps:

[0071] (1) Choline chloride and diethylene glycol are mixed in a molar ratio of 1:3, and stirred at room temperature for 30 minutes to form a uniform transparent liquid, thereby preparing a low eutectic solvent.

[0072] (2) A certain amount of (absolutely dry) ginseng residue is taken, crushed and passed through an 80-mesh sieve, and then placed in a container. A mixture of a low eutectic solvent and water is added at a solid-liquid ratio of 1:20 g / mL, wherein the mixture contains 70% (volume fraction) of the low eutectic solvent; ultrasonic extraction is performed in the container for 30 minutes, and the mixture is centrifuged to collect the extract and the solid residue.

[0073] (3) The supernatant is concentrated to a certain volume by rotary evaporation under reduced pressure. The concentrated extract is precipitated with ethanol at a volume ratio of 1:3 for 20 hours, and then centrifuged. The filtrate is the ginsenoside extract, and the crude ginseng polysaccharide is precipitated and dried and ground into powder.

[0074] (4) The solid residue after extraction in step (2) is washed with pure water until neutral and dried. After drying, it is mixed with water (mass ratio is 1:25) to form a mixed solution, soaked for 12 hours, centrifuged, and the precipitate is taken and dried to obtain ginseng residue dietary fiber.

[0075] The antioxidant properties of the ginseng polysaccharides obtained in Example 1, Example 7 and Example 8 are as follows: Figure 8 shown.

Claims

1. A method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction, characterized in that: The steps include: 1) Mix choline chloride and one of propionic acid, ethylene glycol or diethylene glycol in a molar ratio of 1:3, and stir at room temperature until a homogeneous transparent liquid is obtained to prepare a low eutectic solvent; 2) adding an extraction solvent consisting of the low eutectic solvent in step 1) and water to the crushed ginseng residue, extracting, filtering and collecting the extract to obtain a ginseng residue extract and a solid residue; wherein the volume percentage of the low eutectic solvent in the extraction solvent is 50-90%, and the solid-liquid ratio of ginseng residue to the extraction solvent is 1:15-35 g / mL; 3) After the extract in step 2) is concentrated, ethanol is added for precipitation, and centrifugation is performed to obtain a crude ginseng polysaccharide solid and a ginsenoside extract; 4) The solid residue after extraction in step 2) is washed with pure water until it becomes neutral, soaked in water, centrifuged, dried, and crushed to obtain ginseng residue dietary fiber.

2. The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction according to claim 1, characterized in that: Step 1) preparing a low eutectic solvent composed of choline chloride and propionic acid.

3. The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction according to claim 1, characterized in that: The extraction time in step 2) is 20 to 40 min.

4. The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction according to claim 1, characterized in that: In step 3), the amount of ethanol added is 3 to 4 times the volume of the extract.

5. The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction according to claim 1, characterized in that: The alcohol precipitation time in step 3) is 12 to 24 hours.

6. The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction according to claim 1, characterized in that: The mass ratio of the solid residue to water in step 4) is 1:20 to 1:

30.

7. The method for extracting ginsenosides from ginseng residue and utilizing the residue after extraction according to claim 1, characterized in that: The soaking time in step 4) is 10 to 16 hours.

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