Production method of low-pesticide-residue ginseng stem and leaf extract

Abstract

The invention relates to a production method of a low-pesticide-residue ginseng stem and leaf extract, which comprises the following steps: crushing ginseng stem and leaf raw materials, adding hot water containing alkali, hydrogen peroxide and slow-release calcium peroxide for extraction, and coarsely filtering to obtain an extracting solution; centrifuging the extracting solution to obtain a centrifugal clear solution; enabling the centrifugal clear liquid to pass through a macroporous adsorption resin column, enabling the desorption liquid to pass through an anion exchange resin column, treating the effluent of the anion exchange resin column by using a nanofiltration membrane, continuously adding pure water, continuously performing nanofiltration, adding modified activated carbon into the trapped fluid of the nanofiltration membrane, preserving heat, stirring, and filtering to obtain filtrate; and concentrating and drying the filtrate to obtain the ginseng stem and leaf extract with low pesticide residue. According to the invention, a compound of hydrogen peroxide and slow-release calcium peroxide is adopted as an oxidation system, so that pesticide residues in an extracting solution are effectively reduced from the source of the process; and pesticide residues are further removed by adopting a ginsenoside alcohol phase decoloration mode.

Description

Technical Field

[0001] The invention relates to a method for producing natural active ingredients of plants, and in particular to a method for producing a low-pesticide residue ginseng stem and leaf extract. Background Art

[0002] Ginsenosides are important active ingredients of ginseng. They belong to triterpenoid glycoside compounds and can be divided into protopanaxadiol saponins (PPD-type saponins), protopanaxatriol saponins (PPT-type saponins) and oleanane-type. Studies have found that the physiological activities of ginsenosides are mainly concentrated in the following aspects: 1. Antioxidant effect. Ginsenosides have a strong antioxidant effect. They can effectively inhibit the activity of free radicals, block the production of reactive oxygen species, protect the human body from free radical damage, thereby delaying the aging process and improving the body's immune capacity. 2. Improve cardiovascular disease. Ginsenosides have the functions of lowering blood lipids, lowering blood sugar, inhibiting platelet aggregation and preventing cardiovascular diseases. They can promote the normal functioning of the human cardiovascular function, improve the health level of the blood circulation system, relieve the symptoms of cardiovascular diseases, and play a role in protecting the cardiovascular system. 3. Anti-inflammatory effect. Ginsenosides have a strong anti-inflammatory effect. They can inhibit inflammatory reactions, inhibit the release of cytokines, reduce vascular damage, and relieve inflammatory symptoms, thereby playing a role in preventing and treating inflammatory diseases. 4. Anti-tumor effect. Ginsenosides can inhibit the growth and metastasis of tumor cells, and inhibit the development and spread of tumors by regulating the levels of inflammatory factors, passive immune factors and apoptotic factors, thus playing an anti-tumor role. 5. Immunomodulatory effect. Ginsenosides can regulate the human immune system, promote the body's immune response, improve immune function, prevent viral infection, reduce the risk of infection and protect human health. 6. Neuroprotective effect. Ginsenosides can inhibit the damage of nerve cells, increase the membrane stability of nerve cells, improve the function of nerve cells, protect the health of the nervous system and play a neuroprotective role by inhibiting the release of neurotoxins in the human body. With the continuous deepening of research on the physiological activity of ginsenosides, people have achieved many remarkable results. Therefore, ginsenosides have important applications in drug development, nutritional care and medical cosmetology.

[0003] Ginsenosides are a precious natural compound that has been artificially cultivated and extracted. However, on the one hand, ginseng is very susceptible to pests and diseases during its cultivation, so it has to be sprayed with pesticides many times during its growth cycle (3-7 years); on the other hand, due to the limitations of traditional extraction and processing technology, it is impossible to remove a large amount of pesticide residues in ginseng stems and leaves. Therefore, the pesticide residues in traditional ginseng stem and leaf extracts often exceed the standard (total pesticide residues can exceed 400ppm).

[0004] CN112843109A discloses a method for removing nicotine and triazole pesticide residues from total saponins of saponin plants, which uses ginseng stems and leaves as raw materials, and undergoes crushing, solvent extraction, pH adjustment, filtration, macroporous resin column adsorption, impurity removal, ethanol elution, concentration, organic solvent extraction, macroporous resin column adsorption again, column liquid concentration and drying, etc. to obtain a ginseng stem and leaf total saponin product with nicotine and triazole pesticide residues less than 0.01ppm. The method has cumbersome steps, uses macroporous resin adsorption multiple times, requires the use of flammable, explosive, volatile, toxic and side-effect low-polarity organic solvents, and has unknown removal effects on pesticide residues other than nicotine and triazole, and is not suitable for industrial production.

[0005] CN108042590A discloses a method for preparing a low-pesticide residue ginseng stem and leaf extract, which uses ginseng stem and leaf as raw materials, and obtains the low-pesticide residue ginseng stem and leaf extract through the steps of crushing, ethanol reflux extraction, concentration, impurity removal, centrifugation, methanol dissolution, gel column chromatography, etc. Due to the limitations of gel resin cost and processing volume, the output of the invention method is very small and does not have industrial prospects; in addition, the solvent extract of the ginseng stem and leaf raw material has complex components, and the gel resin is easily contaminated, and it is impossible to achieve multiple cycles of repeated recycling.

[0006] CN104173399A discloses a method for preparing total saponins of ginseng stems and leaves with low pesticide residues, which uses total saponins of ginseng stems and leaves as raw materials, and obtains total saponins of ginseng stems and leaves with low pesticide residues through subcritical extraction, recovery of extract, and evaporation of extraction solvent. This method requires expensive subcritical equipment and uses a large amount of flammable, explosive, volatile, toxic and side-effect low-polarity organic solvents, which is not suitable for industrial production.

[0007] CN104490966A discloses a method for removing residual pesticides from ginseng stem and leaf extracts, which uses ginseng stem and leaf extracts as raw materials, and obtains finished products with pesticide residue concentrations of less than 0.01ppm such as azoxystrobin, carbendazim, procymidone, and propiconazole through hot water dissolution, mixed organic solvent extraction, dilution, macroporous resin adsorption, elution, concentration, and drying. The method also uses a large amount of flammable, explosive, volatile, and toxic low-polarity organic solvents, and due to the organic solvent extraction, the loss of total saponins reaches nearly 15%. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a production method of ginseng stem and leaf extract with low pesticide residues, which has simple process, strong operability, low equipment requirements, low production cost, high total saponin yield, safety, greenness, environmental protection and is suitable for industrial production.

[0009] The technical solution adopted by the present invention to solve the technical problem is as follows: a method for producing a low-pesticide residue ginseng stem and leaf extract comprises the following steps:

[0010] (1) Extraction and centrifugation: Take the raw material of ginseng stems and leaves, crush them, add hot water containing alkali, hydrogen peroxide, and slow-release calcium peroxide to extract, and roughly filter to obtain an extract; centrifuge the extract to obtain a centrifugal supernatant;

[0011] (2) Enrichment and elution of total saponins: The centrifuged supernatant is passed through a macroporous adsorption resin column until the column is completely loaded, first washed with alkaline water, then washed with pure water until the effluent is neutral, and finally resolved with an alcohol-water solution, and the resolved solution is collected for later use;

[0012] (3) Decolorization: passing the analytical solution through an anion exchange resin column and collecting the effluent from the anion exchange resin column;

[0013] (4) Nanofiltration: The effluent from the anion exchange resin column is treated with a nanofiltration membrane, and pure water is continuously added to continue nanofiltration until the retentate reaches the process requirements, then the nanofiltration is stopped and the retentate of the nanofiltration membrane is collected; the process requirements are that the retentate has no alcohol taste and the cumulative volume of the permeate is 10-60 times the weight of the ginseng stem and leaf raw material;

[0014] (5) Modified activated carbon treatment: add modified activated carbon to the retentate of the nanofiltration membrane, keep warm and stir, filter, and obtain a filtrate;

[0015] (6) Concentration and drying: The filtrate is concentrated and dried to obtain a low pesticide residue ginseng stem and leaf extract.

[0016] The low pesticide residue refers to a maximum pesticide residue limit value of ≤0.05 mg / kg, preferably ≤0.02 mg / kg, and more preferably ≤0.01 mg / kg. In a preferred embodiment of the present invention, no pesticide residue is detected in the obtained product by gas chromatography-mass spectrometry and / or liquid chromatography-mass spectrometry, which is lower than LOQ.

[0017] Adding a certain amount of hydrogen peroxide under alkaline heating conditions, its oxidation has a certain promoting decomposition effect on agricultural residues, and converting them into small molecules is convenient for subsequent adsorption and removal. In the prior art, there are methods of using ultrasonic assisted ozone to treat agricultural residues, but on the one hand, the price of ozone generators is relatively expensive, and it is not suitable for large-scale production in industry; and long-term exposure to ozone is toxic to the human body. For liquid phase reagents, strong oxidants such as hydrogen peroxide, calcium hypochlorite, and peracetic acid are also used for oxidation, but the inventors found that these strong oxidants have a certain destructive effect on ginsenosides while removing agricultural residues, resulting in a decrease in the yield of total ginsenosides. Moreover, when using oxidants such as hydrogen peroxide, high-temperature extraction will accelerate the decomposition of hydrogen peroxide, but if the temperature is too low, the extraction rate will decrease, and the yield of total ginsenosides will also be reduced. The method of adding oxidants is also uneconomical and not suitable for large-scale industrial production. The present invention uses a compound of hydrogen peroxide + sustained-release calcium peroxide as an oxidation system, which can effectively reduce agricultural residues and does not affect the yield of total ginsenosides. Hydrogen peroxide is used to compensate for the slower release rate of sustained-release calcium peroxide.

[0018] Preferably, in step (1), the particle size of the raw material is 2-5 mm, the amount of the hot water containing the alkali and the oxidant is 15-30 times the weight of the ginseng stem and leaf raw material (volume-to-weight ratio, L / kg), and the temperature of the hot water is 40-70° C. The temperature of the hot water should not be too high, otherwise the decomposition of hydrogen peroxide will be accelerated and the decomposition and conversion effect on pesticide residues will be lost; the temperature should not be too low, otherwise the extraction of ginsenosides will be affected.

[0019] Preferably, in step (1), in the hot water containing alkali and hydrogen peroxide oxidizing agent, the content of alkali is 0.5-2wt%, the concentration of hydrogen peroxide is 1-2wt%; and the concentration of sustained-release calcium peroxide is 2-4wt%.

[0020] Preferably, in step (1), the sustained-release calcium peroxide is prepared by a preparation method comprising the following steps: calcium peroxide is dispersed in alcohol, dopamine hydrochloride is slowly added under stirring, the pH is adjusted to 8-9, and after the reaction is completed, the solid is centrifuged, washed with alcohol, and dried to obtain sustained-release calcium peroxide. More preferably, the alcohol is ethanol, the concentration of calcium peroxide in the dispersion of calcium peroxide and alcohol is 10-15wt%, the amount of dopamine hydrochloride added is 0.2-0.3 times the mass of calcium peroxide, and the slow addition is completed within 0.5-2h.

[0021] Preferably, in step (1), the extraction method includes but is not limited to traditional fractional extraction, percolation extraction, reflux extraction, countercurrent extraction, pulping extraction, pressing extraction, microwave-assisted extraction, ultrasonic extraction, and pulsed electric field-assisted extraction.

[0022] Preferably, in step (2), the macroporous adsorption resin used in the macroporous adsorption resin column is a non-polar macroporous adsorption resin, a medium-polar macroporous adsorption resin or a weakly polar macroporous adsorption resin, or a combination of two or more of the above resins. The macroporous adsorption resin includes but is not limited to at least one of D101c, AB-8, and D101, the height-to-diameter ratio of the resin column is 3-5:1, the flow rate is 0.5-3BV / h, and the volumetric dosage of the macroporous adsorption resin and the mass ratio of the ginseng stem and leaf raw material is 2-4L:1kg.

[0023] Preferably, in step (2), the alkaline water is an aqueous solution of sodium hydroxide or potassium hydroxide, the mass percentage concentration of the alkaline water is 0.1%-1%, and the amount of the alkaline water is 1-5BV. The purpose of using alkaline water for washing impurities is, first, to partially remove chlorophyll and other pigment impurities adsorbed on the macroporous resin, and second, to remove a small amount of agricultural residues adsorbed on the macroporous resin; the alcohol aqueous solution is a mixed solution of at least one of methanol and ethanol and water at an alcohol volume concentration of 60-80%, such as an ethanol aqueous solution with an alcohol volume fraction of 70%.

[0024] Preferably, in step (3), the type of the anion exchange resin is a macroporous strong basic anion exchange resin or a macroporous weak basic anion exchange resin, including but not limited to at least one of D941, LX-T5, and D945; the amount of the anion exchange resin is 0.1-1 times the weight of the ginseng stem and leaf raw material, preferably 0.25-0.4 times (volume / weight ratio, L / kg); the height-to-diameter ratio of the anion exchange resin column is 3-8:1; the flow rate of the ethanol analysis solution through the anion exchange resin column is 0.3-3BV / hour. The purpose of using anion exchange resin is, first, to remove a large amount of impurities such as pigments in the analysis solution, and second, to partially remove agricultural residues in the analysis solution.

[0025] In the production process of ginseng stem and leaf extract, agricultural residues are enriched and eluted by macroporous adsorption resin, resulting in excessive agricultural residues in ginseng stem and leaf extract. Due to the characteristics of its own structure, macroporous anion exchange resin has the characteristics of a part of macroporous adsorption resin in addition to the characteristics of anion exchange, so it also has the effect of enrichment on agricultural residues. At the same time, the inventor also found that if in the aqueous phase solution, the ginseng stem and leaf extract is decolorized using macroporous anion exchange resin, although the removal effect of agricultural residues is very good, some ginsenosides are adsorbed by macroporous anion exchange resin, resulting in the loss of ginsenosides. Therefore, the present invention adopts alcohol phase solution (i.e.: macroporous adsorption resin analytical solution, ethanol is not recovered) directly through the macroporous anion exchange resin column, although the removal effect of agricultural residues is slightly inferior to the aqueous phase, it also has the effect of decolorization and ginsenosides will not be lost.

[0026] Preferably, in step (4), the molecular weight cutoff of the nanofiltration membrane is 300-800Da, and the pressure of the nanofiltration is 0.1-0.6Mpa. The purpose of using the nanofiltration membrane for treatment is that by selecting a nanofiltration membrane with a suitable molecular weight cutoff, ginsenosides will be retained by the nanofiltration membrane due to their large molecular weight; at the same time, since the molecular weight of pesticide residues is relatively small, they can all pass through the nanofiltration membrane, thereby achieving the purpose of fully removing pesticide residues. If the molecular weight cutoff of the nanofiltration membrane is too small, the pesticide residues will not be able to pass through the nanofiltration membrane, and the purpose of removal cannot be achieved; if the molecular weight cutoff of the nanofiltration membrane is too large, ginsenosides will pass through the nanofiltration membrane, resulting in product loss.

[0027] Preferably, in step (4), the amount of pure water added and continued nanofiltration is 10-60 times the weight of the ginseng stem and leaf raw material (volume / weight ratio, L / kg). The purpose of adding pure water and continuing nanofiltration is to extend the nanofiltration time, thereby increasing the amount of pesticide residues passing through the nanofiltration membrane, thereby achieving the purpose of fully removing pesticide residues.

[0028] Preferably, in step (5), the modified activated carbon is obtained by mixing the activated carbon and the modifier, and then performing heat treatment, neutralization, ultrasonic washing, water washing, and drying; the modifier includes potassium hydroxide / sodium hydroxide and potassium permanganate in a mass ratio of 5-10:1; more preferably, the amount of the modifier is 0.1-0.3 times the mass of the activated carbon. Further, the modified activated carbon is obtained by a preparation method comprising the following steps: the activated carbon and the modifier are mixed evenly, put into a heating furnace under an inert atmosphere, pre-burned at 300-400°C for 2-3h, then heated to 600-700°C, kept warm for activation for 5-10h, neutralized after cooling, ultrasonically cleaned, and dried to obtain the modified activated carbon.

[0029] Preferably, in step (5), the amount of the modified activated carbon is 0.1%-2% of the weight of the ginseng stem and leaf raw material, preferably 1-1.5wt%, the insulation temperature is 50-60°C, and the stirring time is 2-4 hours. The purpose of using modified activated carbon is to completely remove the very small amount of pesticide residues that may exist in the nanofiltration retentate.

[0030] In the present invention, 1 BV=1 column volume.

[0031] Principle of the method of the present invention:

[0032] The total pesticide residue in ordinary ginseng stem and leaf extracts can be as high as 400 mg / kg; however, the EC396 Regulation of the European Parliament and the Council of Europe and the USP / NF Standard of the United States Pharmacopoeia clearly stipulate that the maximum residue limit of plant extract products or other functional products (including ginseng stem and leaf extracts) imported from China is only 0.05 mg / kg or even 0.01 mg / kg. For such a high amount of pesticide residues, any single technical means of removing pesticide residues cannot be achieved in one step and overnight. Therefore, the method of the present invention adopts a new step-by-step, interlocking combined treatment method. First, a combination of hydrogen peroxide and sustained-release calcium peroxide is used as the oxidation system in the extraction step, which effectively reduces the pesticide residues in the extract at the source of the process and reduces the burden of pesticide residue treatment in subsequent steps; second, before the analysis of the macroporous adsorption resin, alkaline solution is used to remove impurities and remove a small amount of pesticide residues; third, the ginsenoside alcohol phase decolorization method is creatively adopted to ensure that there is no loss of ginsenosides and the decolorization effect is significant, while some pesticide residues can be further removed; from then on, the nanofiltration membrane plays a "main" role in removing pesticide residues, and most of the pesticide residues are "annihilated"; finally, the modified activated carbon is responsible for "cleaning the battlefield", and the very small amount of pesticide residues that may exist in the nanofiltration retentate can be completely removed under the action of the modified activated carbon.

[0033] The beneficial effects of the method of the present invention are as follows:

[0034] (1) The method of the present invention provides a method for producing a low-pesticide residue ginseng stem and leaf extract, and the product quality meets the quality standards of the European Union and the United States.

[0035] (2) The ginseng stem and leaf extract prepared by the method of the present invention has a yield of 92% of total ginsenosides.

[0036] (3) The method of the present invention has an exquisite process design, simple process, strong operability, low equipment requirements, low production cost, safety, green, environmental protection, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is Example 1, Pesticide Residue Detection Report 1 of Ginseng Stem and Leaf Extract.

[0038] Figure 2 This is Example 1, Pesticide Residue Detection Report 2 of Ginseng Stem and Leaf Extract.

[0039] Figure 3 This is Example 2, Pesticide Residue Detection Report 1 of Ginseng Stem and Leaf Extract.

[0040] Figure 4 This is Example 2, Pesticide Residue Detection Report 2 of Ginseng Stem and Leaf Extract.

[0041] Figure 5This is the pesticide residue detection report 1 of ginseng stem and leaf extract of comparative example 1.

[0042] Figure 6 This is the pesticide residue detection report 2 of ginseng stem and leaf extract of comparative example 1.

[0043] Figure 7 This is the pesticide residue detection report 3 of ginseng stem and leaf extract of comparative example 1.

[0044] Figure 8 This is comparative example 2, pesticide residue detection report 1 of ginseng stem and leaf extract.

[0045] Fig. 9 This is comparative example 2, pesticide residue detection report 2 of ginseng stem and leaf extract. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with the embodiments.

[0047] The ginseng stem and leaf raw materials used in the embodiments of the present invention were purchased from Ji'an, Jilin, wherein the mass percentage content of total ginsenosides was 4.78%; the macroporous adsorption resin and macroporous anion exchange resin used in the embodiments of the present invention were purchased from Xi'an Lanxiao Technology New Materials Co., Ltd.; the alumina used in the embodiments of the present invention was purchased from Zibo Shuoren Alumina Technology Co., Ltd.; the raw materials or chemical reagents used in the embodiments of the present invention, unless otherwise specified, were obtained through conventional commercial channels.

[0048] In the embodiment of the present invention, the mass percentage content of total ginsenosides was detected by high performance liquid chromatography external standard method.

[0049] In the embodiment of the present invention, the UV content of ginsenosides is detected by ultraviolet spectrophotometry.

[0050] In the embodiments of the present invention, gas chromatography-mass spectrometry and / or liquid chromatography-mass spectrometry are used to detect pesticide residues.

[0051] Preparation Example 1 Preparation of sustained-release calcium peroxide

[0052] 10g of calcium peroxide dispersion in ethanol is formed into a calcium peroxide alcohol dispersion with a solid content of 10%, and 3g of dopamine hydrochloride is slowly added under stirring. After 0.5h of addition, the pH is adjusted to 8, and stirring is continued for 2h. Centrifugation is performed at 3000rpm, and the solid phase is washed three times with anhydrous ethanol and vacuum dried to obtain sustained-release calcium peroxide.

[0053] Preparation Example 2 Preparation of modified activated carbon

[0054] 10kg of commercially available granular activated carbon and 3kg of modifier (a mixture of KOH and potassium permanganate in a mass ratio of 10:1) were mixed evenly, ground into a powder of about 1mm in size, and placed in an intelligent temperature-controlled heating furnace, which was filled with nitrogen in advance. The mixture was pre-burned at 300°C for 2h, with a water content of <0.1%, and then heated to 600°C, kept warm for 5h, cooled to room temperature, neutralized with 1wt% dilute hydrochloric acid, and then placed in an ultrasonic cleaner, immersed in 90°C hot water under ultrasonic conditions (300W, 150kHz) for 2h, during which the hot water was replaced twice; finally, the mixture was washed with water until the pH of the washing liquid was 6.8, taken out, and dried to obtain modified activated carbon. According to GB / T7702.20-2008, the specific surface area (BET) of the modified activated carbon obtained in this preparation example was tested to be 2420m 2 / g.

[0055] Example 1

[0056] (1) Extraction and centrifugation: 200 kg of ginseng stem and leaf raw material was crushed to a particle size of 2-5 mm, and placed in an extraction tank. A total of 5 tons of 62° C. hot water was used for three extractions (the three extraction times were 2 h, 2 h, and 1 h, respectively). The hot water contained 0.7 wt % NaOH, 2 wt % hydrogen peroxide, and 3 wt % of the sustained-release calcium peroxide prepared in Preparation Example 1. After extraction, the extract was filtered to obtain an extract; the extract was centrifuged in a horizontal screw centrifuge to obtain a centrifugal clear liquid;

[0057] (2) Enrichment and elution of total saponins: The centrifuged supernatant was passed through a macroporous adsorption resin column (wherein the model of the macroporous adsorption resin was D101c, the amount of the macroporous adsorption resin was 400 L, and the height-to-diameter ratio of the resin column was 4:1) at a flow rate of 1 BV / h until the column was completed, and then the impurities were washed with 3 BV of a 0.5% sodium hydroxide aqueous solution by mass percentage, and then washed with pure water until the effluent was neutral, and finally analyzed with 2 BV of 70% ethanol by volume, and the ethanol analysis solution was collected for standby use;

[0058] (3) Decolorization: The ethanol solution was passed through an anion exchange resin column (wherein the anion exchange resin was D941, the amount of anion exchange resin was 50 L, and the height-to-diameter ratio of the resin column was 4:1) at a flow rate of 0.3 BV / h, and the effluent from the anion exchange resin column was collected;

[0059] (4) Nanofiltration: The effluent from the anion exchange resin column was passed through a nanofiltration device and subjected to nanofiltration treatment using a nanofiltration membrane with a molecular weight cutoff of 500 Da at a pressure of 0.4 MPa. When the volume of the retentate was less than 400 L, pure water was continuously added to continue the nanofiltration (the total amount of water added was about 7 m 3 ), until the volume of the retentate is about 400 L, then stop the nanofiltration and collect the nanofiltration membrane retentate;

[0060] (5) Modified activated carbon treatment: 2.5 kg of the modified activated carbon obtained in the preparation example was added to the nanofiltration membrane retentate, and the mixture was stirred at 60° C. for 4 h, filtered, and an activated carbon-treated filtrate was obtained;

[0061] (6) Concentration and drying: The activated carbon-treated filtrate was concentrated and dried to obtain 18.67 kg of low pesticide residue ginseng stem and leaf extract.

[0062] The high performance liquid chromatography external standard method was used to determine that the mass percentage of ginsenosides in the low pesticide residue ginseng stem and leaf extract obtained in this example was 47.61%, and the yield of ginsenosides was 92.98%.

[0063] The UV content of ginsenosides in the low-pesticide residue ginseng stem and leaf extract obtained in this embodiment is 89.25% as determined by ultraviolet spectrophotometry. The general content requirements for ginsenosides in the ginseng stem and leaf extract sold on the market are: HPLC total saponin content ≥45%, and ultraviolet spectrophotometry (i.e. UV) total saponin content ≥80%. The two different detection methods of HPLC and UV result in relatively different detection results, but both are general content requirements for the product in the industry.

[0064] The results of gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry showed that the detection results of 243 pesticide residues in the low pesticide residue ginseng stem and leaf extract obtained in this example were not detected or were below the detection limit. The test report is as follows: Figure 1 and Figure 2 shown.

[0065] Example 2

[0066] (1) Extraction and centrifugation: 200 kg of ginseng stem and leaf raw material was taken and crushed to a particle size of 2-5 mm. The raw material was first soaked with about 150 kg of water and then placed in a percolation tank. A total of 3 tons of hot water at 65° C. was used for percolation extraction. The hot water contained 1 wt % NaOH, 1.5 wt % hydrogen peroxide, and 2 wt % of the sustained-release calcium peroxide prepared in Preparation Example 1. The percolation flow rate was 300 L / h. The extract was coarsely filtered to obtain an extract. The extract was centrifuged in a horizontal screw centrifuge to obtain a centrifugal clear liquid.

[0067] (2) Enrichment and elution of total saponins: The centrifuged supernatant was passed through a macroporous adsorption resin column (wherein the model of the macroporous adsorption resin was AB-8, the amount of the macroporous adsorption resin was 450 L, and the height-to-diameter ratio of the resin column was 4.5:1) at a flow rate of 1 BV / h until the column loading was completed, and then the impurities were washed with 2.5 BV of a 0.6% potassium hydroxide aqueous solution by mass percentage, and then washed with pure water until the effluent was neutral, and finally analyzed with 2 BV of 70% ethanol by volume, and the ethanol analysis solution was collected for standby use;

[0068] (3) Decolorization: the ethanol analysis solution was passed through an anion exchange resin column (wherein the anion exchange resin was LX-T5, the amount of anion exchange resin was 80 L, and the height-to-diameter ratio of the resin column was 6:1) at a flow rate of 0.5 BV / h, and the effluent from the anion exchange resin column was collected;

[0069] (4) Nanofiltration: The effluent from the anion exchange resin column was passed through a nanofiltration device and subjected to nanofiltration treatment using a nanofiltration membrane with a molecular weight cutoff of 600 Da at a pressure of 0.3 MPa. When the volume of the retentate was less than 400 L, pure water was continuously added to continue the nanofiltration (the total amount of water added was about 6 m 3 ), until the volume of the retentate is about 400 L, then stop the nanofiltration and collect the nanofiltration membrane retentate;

[0070] (5) Modified activated carbon treatment: 3 kg of modified activated carbon obtained in the preparation example was added to the nanofiltration membrane retentate, and the mixture was stirred at 55° C. for 3 h, and filtered to obtain an activated carbon-treated filtrate;

[0071] (6) Concentration and drying: The activated carbon-treated filtrate was concentrated and dried to obtain 18.25 kg of low pesticide residue ginseng stem and leaf extract.

[0072] Determined by HPLC external standard method, the mass percentage content of ginsenosides in the low pesticide residue ginseng stem and leaf extract obtained in this example is 48.30%, and the yield of ginsenosides is 92.20%.

[0073] The UV content of ginsenosides in the low pesticide residue ginseng stem and leaf extract obtained in this example was determined by ultraviolet spectrophotometry to be 90.39 wt %.

[0074] According to the gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, the detection result of 243 pesticide residues in the low pesticide residue ginseng stem and leaf extract obtained in this example is that only 0.016 mg / kg of oxadimethoxine is detected, and the other pesticide residues are not detected or are below the detection limit. The test report is as follows: Figure 3 and Figure 4 shown.

[0075] Comparative Example 1: Traditional Ginseng Stem and Leaf Extract Production Method

[0076] (1) Extraction and filtration: Take 1 kg of ginseng stem and leaf raw material, crush it to a particle size of 2-5 mm, put it into a small pilot extraction tank, use a total of 25 L of 92° C. hot water, extract it three times (the three extraction times are 2 h, 2 h, and 1 h respectively), and coarsely filter to obtain an extract; filter the extract with filter paper to obtain an extract filtrate.

[0077] (2) Adsorption: The extraction filtrate is passed through a macroporous adsorption resin column (wherein the model of the macroporous adsorption resin is D101c, the amount of the macroporous adsorption resin is 2 L, and the height-to-diameter ratio of the resin column is 4.5:1) at a flow rate of 1 BV / h until the column loading is completed.

[0078] (3) Washing: Wash the macroporous adsorption resin with 6L of pure water at a flow rate of 1BV / hour.

[0079] (4) Desorption: Desorb with 2 BV of 70% ethanol at a flow rate of 1 BV / hour, and collect the desorbed liquid.

[0080] (5) Decolorization: Add 120 g of magnesium oxide to the analytical solution, stir at room temperature for 3 hours, filter and collect the filtrate.

[0081] (6) Concentration and drying: The filtrate treated with magnesium oxide was concentrated under reduced pressure using a rotary evaporator, and the concentrate was dried in vacuo to obtain 89 g of ginseng stem and leaf extract.

[0082] The ginsenoside content of the ginseng stem and leaf extract obtained in this comparative example was 46.78% by mass as determined by the HPLC external standard method, and the ginsenoside yield was 87.10%.

[0083] The UV content of ginsenosides in the ginseng stem and leaf extract obtained in this comparative example was determined by ultraviolet spectrophotometry to be 85.71%.

[0084] According to the determination by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, the test results of 25 out of 243 pesticide residues in the ginseng stem and leaf extract obtained in this comparative example were detected, and the total residue amount exceeded 400 mg / kg. The test report is as follows: Figure 5 , Figure 6 and Figure 7 shown.

[0085] Comparative Example 2

[0086] The other conditions are the same as those in Example 1, except that in step (1), the hot water contains 0.7 wt % NaOH and 5 wt % hydrogen peroxide.

[0087] Finally, 18.38 kg of low pesticide residue ginseng stem and leaf extract was obtained.

[0088] The high performance liquid chromatography external standard method was used to determine that the mass percentage content of ginsenosides in the low pesticide residue ginseng stem and leaf extract obtained in this example was 46.92%, and the yield of ginsenosides was 90.21%.

[0089] The results of gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry showed that the detection results of 243 pesticide residues in the low pesticide residue ginseng stem and leaf extract obtained in this comparative example were as follows: propiconazole 0.011 mg / kg, boscalid 0.018 mg / kg, tebuconazole 0.027 mg / kg, methacryloyl 0.16 mg / kg, difenoconazole 0.029 mg / kg, and the remaining pesticide residues were not detected or were below the detection limit. The test report is as follows: Figure 8 and Fig. 9 shown.

Claims

1. A method for producing a low-pesticide residue ginseng stem and leaf extract, characterized in that: The following steps are involved: (1) Extraction and centrifugation: Take the raw material of ginseng stems and leaves, crush them, add hot water containing alkali, hydrogen peroxide, and slow-release calcium peroxide to extract, and roughly filter to obtain an extract; centrifuge the extract to obtain a centrifugal supernatant; (2) Enrichment and elution of total saponins: The centrifuged supernatant is passed through a macroporous adsorption resin column until the column is completely loaded, first washed with alkaline water, then washed with pure water until the effluent is neutral, and finally resolved with an alcohol-water solution, and the resolved solution is collected for later use; (3) Decolorization: passing the analytical solution through an anion exchange resin column and collecting the effluent from the anion exchange resin column; (4) Nanofiltration: The effluent from the anion exchange resin column is treated with a nanofiltration membrane, and pure water is continuously added to continue nanofiltration until the retentate reaches the process requirements, then the nanofiltration is stopped and the retentate of the nanofiltration membrane is collected; the process requirements are that the retentate has no alcohol taste and the cumulative volume of the permeate is 10-60 times the weight of the ginseng stem and leaf raw material; (5) Modified activated carbon treatment: add modified activated carbon to the retentate of the nanofiltration membrane, keep warm and stir, filter, and obtain a filtrate; (6) Concentration and drying: The filtrate is concentrated and dried to obtain a low pesticide residue ginseng stem and leaf extract.

2. The production method according to claim 1, characterized in that In step (1), the particle size of the raw material is 2-5 mm, the amount of hot water containing alkali and oxidant is 15-30 times the weight of the ginseng stem and leaf raw material, volume weight ratio, L / kg, and the temperature of the hot water is 40-70°C.

3. The production method according to claim 1, characterized in that In step (1), in the hot water containing alkali and hydrogen peroxide oxidizing agent, the content of alkali is 0.5-2wt%, the concentration of hydrogen peroxide is 1-2wt%; and the concentration of slow-release calcium peroxide is 2-4wt%.

4. The production method according to claim 1, characterized in that In step (1), the sustained-release calcium peroxide is prepared by a preparation method comprising the following steps: dispersing calcium peroxide in alcohol, slowly adding dopamine hydrochloride under stirring conditions, then adjusting the pH to 8-9, and after the reaction is completed, centrifuging, washing the solid with alcohol, and drying to obtain the sustained-release calcium peroxide; Preferably, the alcohol is ethanol, the concentration of calcium peroxide in the dispersion of calcium peroxide and alcohol is 10-15wt%, the amount of dopamine hydrochloride added is 0.2-0.3 times the mass of calcium peroxide, and the slow addition is completed within 0.5-2h.

5. The production method according to claim 1, characterized in that: In step (2), the macroporous adsorption resin used in the macroporous adsorption resin column is a non-polar macroporous adsorption resin, a medium-polar macroporous adsorption resin or a weak-polar macroporous adsorption resin, or a combination of two or more of the above resins; Preferably, the macroporous adsorption resin includes but is not limited to at least one of D101c, AB-8, and D101, the height-to-diameter ratio of the resin column is 3-5:1, the flow rate is 0.5-3BV / h, and the ratio of the volume of the macroporous adsorption resin to the mass of the ginseng stem and leaf raw material is 2-4L:1kg.

6. The production method according to claim 1, characterized in that: In step (2), the alkaline water is an aqueous solution of sodium hydroxide or potassium hydroxide, the mass percentage concentration of the alkaline water is 0.1%-1%, and the amount of the alkaline water is 1-5BV.

7. The production method according to claim 1, characterized in that: In step (3), the type of the anion exchange resin is a macroporous strong alkaline anion exchange resin or a macroporous weak alkaline anion exchange resin, including but not limited to at least one of D941, LX-T5, and D945; the amount of the anion exchange resin is 0.1-1 times, preferably 0.25-0.4 times, the weight of the ginseng stem and leaf raw material, volume / weight ratio, L / kg; the height-to-diameter ratio of the anion exchange resin column is 3-8:

1.

8. The production method according to claim 1, characterized in that: In step (4), the molecular weight cut-off of the nanofiltration membrane is 300-800Da, and the pressure of the nanofiltration is 0.1-0.6Mpa; and / or The amount of pure water added and continued nanofiltration is 10-60 times the weight of the ginseng stem and leaf raw material, volume / weight ratio, L / kg.

9. The production method according to claim 1, characterized in that: In step (5), the modified activated carbon is obtained by uniformly mixing activated carbon and a modifier, and then subjecting the mixture to heat treatment, neutralization, ultrasonic washing, water washing, and drying; the modifier comprises potassium hydroxide / sodium hydroxide and potassium permanganate in a mass ratio of 5-10:1; Preferably, the amount of the modifier is 0.1-0.3 times the mass of the activated carbon.

10. The production method according to claim 1, characterized in that: In step (5), the amount of modified activated carbon is 0.1%-2% of the weight of the ginseng stem and leaf raw material, preferably 1-1.5wt%, the insulation temperature is 50-60°C, and the stirring time is 2-4 hours.

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