A method for extracting hesperidin

Abstract

A method for extracting hesperidin comprises the following steps: (1) crushing; (2) removing impurities: putting the powder of Citrus aurantium into an extraction tank, adding a sodium carbonate solution to stir and remove impurities, and collecting solids; (3) washing; (4) extracting: putting the washed solid into an extraction tank, adding an extraction solvent to stir, and collecting the extract; (5) acid adjustment and crystallization; (6) filtering; (7) drying the crystals to obtain the hesperidin product. The method is simple to operate, and the time for impurity removal and extraction is shortened from 48 hours in the existing method to 2.5 to 4.0 hours, with low energy consumption, and the production capacity is doubled without increasing the plant and equipment, and the operability is strong, and it is particularly suitable for industrial production.

Description

Technical Field

[0001] The invention relates to a method for extracting hesperidin, and in particular to a method for extracting hesperidin with high production efficiency. Background Art

[0002] Hesperidin (hesperidin) is generally extracted from the physiological fruit drop of citrus or citrus peel during the growth process of citrus.

[0003] In view of the seasonality of citrus fruiting, fresh fruits are generally collected, dried and stored.

[0004] Hesperidin belongs to the dihydroflavonoids class of drugs. Its pharmacological effects are as follows: It is used in combination with vitamin C in clinical practice to treat various bleeding diseases caused by increased vascular fragility. Hesperidin can excite isolated and in situ frog hearts. Intravenous injection of hesperidin can enhance the contractility of in situ rabbit hearts, but has little effect on heart rate, and increases blood output while strengthening cardiac contractility. It has also been reported that hesperidin has a short and obvious dilation effect on the peripheral blood vessels of cats, and also has anti-inflammatory, antiviral, anti-ulcer, and choleretic effects.

[0005] The existing hesperidin extraction method generally includes the following steps: (1) crushing the raw material Citrus aurantium into coarse particles; (2) boiling; (3) washing; (4) percolation to remove impurities; (5) percolation extraction; (6) acid adjustment; (7) filtering; (8) drying. In the existing process, Citrus aurantium must first be crushed into coarse particles, because if it is not crushed into coarse particles, the subsequent percolation removal and percolation extraction will not be able to proceed (solid-liquid separation is difficult, and the liquid cannot flow out). Since it is a coarse particle, it must be boiled to destroy the cell wall and cell membrane, thereby improving the efficiency of percolation. Boiling means energy consumption such as steam. Due to the large particles, more than 40BV of impurity removal solvent must be used to remove impurities completely (the product content can reach more than 90% to be considered a qualified product). At the same time, more than 45BV of percolation extraction must be used to extract cleanly (to ensure the extraction yield). Together with the water from boiling and washing, the discharge volume reaches more than 100BV. It takes 48-50 hours to produce a batch of qualified hesperidin products, which has low production efficiency.

[0006] CN 106866758 A discloses a process for extracting hesperidin from tangerine peel, which comprises the following steps: crushing - heat preservation and pressure maintenance - cooling - alkali solution and enzyme treatment - stirring and standing - neutralization - re-dissolving - resin adsorption - elution - evaporation and drying. This process requires the use of a large amount of organic solvent during elution, resulting in a large amount of wastewater, a complex process, a long time consumption, and the use of steam, which has high energy consumption.

[0007] CN 109180747 A discloses a method for extracting hesperidin, comprising: grinding the raw material with alkaline water, washing and removing impurities with weak alkaline water at low temperature; adding alkaline water with a pH value of 12-14, stirring at room temperature for 1-2 hours, filtering the solid and liquid through a plate and frame to obtain an extract; filtering the extract through a ceramic membrane to obtain an ultrafiltrate; adjusting the pH value of the obtained ultrafiltrate to 5-6.5 by adding acid, and standing and precipitating for 8-10 hours; washing the precipitate with water until it is nearly neutral, filtering, and drying and crushing the filter cake in a dryer to obtain a finished product. This method uses alkaline water to grind the raw materials, which easily leads to the raw materials becoming a pot of porridge and cannot maintain granular shape. When warm water is used to remove impurities, the slurry system is in a paste state and very thick. In addition, the impurities are removed by natural outflow (screen filtration), the outflow speed is very slow, and the impurity removal liquid is not easy to flow cleanly, resulting in unqualified products; and the treatment of the extract requires the use of a ceramic membrane. When the ceramic membrane is used for treatment, the temperature of the extract will increase, and due to the long time of filtration using the ceramic membrane, the hesperidin residue in the solution will increase, resulting in a low product yield; and the concentrated concentrate not only requires a large amount of water to top up, which will produce a lot of sewage, but also has high energy consumption (the power of the high-pressure pump supporting the ceramic membrane with a processing capacity of 10T / h reaches 100kw).

[0008] CN 111362993 A discloses a new process for extracting hesperidin, comprising the following steps: step A. crushing the raw material of Citrus aurantium with a crushing particle size of 40-60 mesh; step B. pretreating the crushed raw material with a sodium citrate solution for 3-5 hours, and controlling the concentration of the sodium citrate solution to be 1%-5%; step C. filtering after treatment, adding the filter residue to an alkaline extracting solution, controlling the concentration to be 0.5%-2.5%, and extracting for 3-6 hours; step D. firstly coarsely filtering the alkaline extracting solution, and then fine filtering, and transferring the filtrate to a stirring tank; step E. slowly adding acid to the extracting filtrate to adjust the pH value during the stirring process, and controlling the pH value to be 4.5-6.5, and waiting for crystallization for 6-12 hours; step F. passing the crystallization liquid through a plate frame, and washing the filter cake with purified water until it is colorless, blowing the filter cake dry, and transferring it to a drying box for drying, and the drying temperature is 70-105°C. This method uses sodium citrate to remove impurities. Since alkaline solution is used for the extraction of hesperidin, hesperidin and impurities such as naringin and isonaringin are extracted at the same time. In theory, sodium citrate cannot remove impurities similar to hesperidin, and can only remove impurities such as colloid. The resulting product is unqualified, with low purity and yield. In addition, this method takes a long time to operate and has low production efficiency.

[0009] At present, the large-scale production of hesperidin has problems such as high difficulty, low yield, long cycle, difficulty in industrialization or very low profits after industrialization. Summary of the invention

[0010] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for extracting hesperidin which has simple process, low production cost, environmental protection and energy saving, high production efficiency and is suitable for large-scale production.

[0011] The technical solution adopted by the present invention to solve the technical problem is a method for extracting hesperidin, comprising the following steps:

[0012] (1) Crushing: drying the raw material of Citrus aurantium, crushing and sieving to obtain Citrus aurantium powder;

[0013] (2) removing impurities: putting the Fructus Aurantii Immaturus powder obtained in step (1) into an extraction tank, adding sodium carbonate solution and stirring to remove impurities, then separating the solid and liquid, and collecting the solid;

[0014] (3) Water washing: the solid obtained in step (2) is placed in an extraction tank, water is added and stirred, washed with water, and then the solid-liquid separation is performed to collect the solid;

[0015] (4) Extraction: the solid obtained in step (3) is placed in an extraction tank, an extraction solvent is added, stirred, and then the solid-liquid separation is performed, and the extract is collected;

[0016] (5) Acid adjustment and crystallization: adding an acidic reagent to the extract obtained in step (4) under air pressure stirring, adjusting the pH value of the extract to ≤7, and allowing the extract to stand for crystallization to obtain a hesperidin acidified solution containing hesperidin crystals;

[0017] (6) filtration, filtering the acidified liquid containing hesperidin wet crystals obtained in step (5) using a filtering device to obtain hesperidin wet crystals;

[0018] (7) Drying: Drying the wet hesperidin crystals obtained in step (6) to obtain the hesperidin product.

[0019] Furthermore, in step (1), the drying is to control the moisture content of the Citrus aurantium raw material to be 8-18%; and the pulverizing is to pulverize the Citrus aurantium raw material to a particle size of 10-100 mesh.

[0020] Furthermore, in step (2), the concentration of the sodium carbonate solution is 0.2-0.5 wt %. When the concentration is too high, hesperidin in the product will also be removed, reducing the yield of hesperidin; if the concentration is too low, some impurities in the immature bitter orange will not be completely removed, resulting in unqualified products.

[0021] In step (2), the purpose of using sodium carbonate solution to remove impurities in the present invention is that the pH value of the sodium carbonate solution with a mass concentration of 0.2-0.5 wt% is about 10-11, which is a medium-strong base and can remove other acidic substances in the Citrus Aurantium Dulcis powder, such as pectin, alkaline pectin, and impurities such as naringin and isonaringin, while hesperidin remains in the Citrus Aurantium Dulcis powder. If the sodium carbonate solution is replaced with other alkaline solutions, such as sodium citrate solution (pH value is about 8), the purpose of sufficient impurity removal cannot be achieved, because sodium citrate can only remove alkaline pectin and pectin, and the removal effect of impurities such as naringin, which have similar properties to hesperidin, is very poor.

[0022] Furthermore, in step (2), the amount of sodium carbonate added is 6-15% of the mass of the Citrus aurantium powder, or the amount of the sodium carbonate solution added is 10-30 times the mass of the Citrus aurantium powder.

[0023] Furthermore, in step (2), the stirring time is 1-3 hours.

[0024] Furthermore, in step (3), the water washing time is 0.2 to 0.5 hours.

[0025] Furthermore, in step (3), the water used for washing is tap water.

[0026] Furthermore, in step (3), the amount of water added is 10-40 times the mass of the solid obtained in step (2).

[0027] The purpose of water washing in step (3) is to remove the sodium carbonate solution and other water-soluble impurities mixed in the solid obtained in step (2). If the water washing is not sufficient, on the one hand, the carbonate ions remaining in step (2) will form precipitation with the calcium ions in step (4), increasing the difficulty of extraction; on the other hand, other water-soluble impurities remaining in step (2) will follow the solid into the extraction tank, and in the extraction process of step (4), since the extraction solvent is a mixed aqueous solution of sodium hydroxide + calcium hydroxide, the water-soluble impurities will continue to remain in the extract and cannot be removed, thereby reducing the purity of the product.

[0028] Furthermore, in step (4), the extraction solvent is a mixed solution of water+sodium hydroxide+calcium hydroxide.

[0029] Furthermore, in step (4), the amount of water added is 15-30 times the amount of the Citrus aurantium, the amount of sodium hydroxide added is 1-6% of the amount of the Citrus aurantium, and the amount of calcium hydroxide added is 1-10% of the amount of the Citrus aurantium.

[0030] Furthermore, in step (4), the extraction solvent is prepared by adding 1.0-6.0kg NaOH + 1.0-10.0kg calcium hydroxide to 1m³ drinking water; the feed ratio of the extraction solvent is 15-30BV of extraction solvent per 200kg of material.

[0031] Furthermore, in step (4), the extraction solvent is preferably prepared by adding 1m³ of drinking water to every 2.0-4.0kg of NaOH + every 1.5-4.0kg of calcium hydroxide.

[0032] In step (4), the purpose of using a mixed solution of water + sodium hydroxide + calcium hydroxide as the extraction solvent is that calcium hydroxide contains calcium ions, which can further seal impurities (i.e., form impurity calcium precipitation, such as pectin calcium, etc.), and calcium hydroxide is cheaper than sodium hydroxide, which effectively reduces production costs from the perspective of large-scale production savings.

[0033] If only sodium hydroxide aqueous solution is used, the quality of hesperidin product will be unqualified, because calcium hydroxide has the effect of further calcium sealing impurities; if only calcium hydroxide aqueous solution is used, the pH value of the calcium hydroxide aqueous solution is not enough, and it is difficult to completely extract hesperidin. If the amount of calcium hydroxide is further increased, a large amount of impurity precipitation will be formed, which will wrap up hesperidin and make hesperidin unable to react with hydroxide ions, thereby resulting in a decrease in the yield of the product.

[0034] The amounts of calcium hydroxide and sodium hydroxide used in the present invention are determined according to the pH value of the extract. Since hesperidin reacts with alkali to form a water-soluble alkaline salt, it can be dissolved in water (when the acid is readjusted to become weakly acidic, hesperidin precipitation will be re-formed), which will inevitably consume hydroxide ions. If the hydroxide ions in the liquid are insufficient, part of the hesperidin cannot react to form a water-soluble product dissolved in the extract, which will affect the hesperidin yield; if the hydroxide ions are excessive (i.e., too much sodium hydroxide and calcium hydroxide are added), unnecessary waste of sodium hydroxide and calcium hydroxide reagents will be caused, and the difficulty of sewage treatment will be increased in the subsequent wastewater treatment process.

[0035] Furthermore, in step (4), the stirring time is 1.0 to 1.5 hours.

[0036] Furthermore, in step (5), the acidic reagent is dilute hydrochloric acid; and the pH value is 5.0-6.5.

[0037] Furthermore, in step (6), the filtration pressure of the plate and frame filtration is ≥ 0.3Mpa.

[0038] Furthermore, in step (7), the drying temperature is 60-80°C.

[0039] The principle of the present invention is: firstly drying the raw material of Citrus aurantium and crushing it into Citrus aurantium powder, increasing the contact area between the raw material of Citrus aurantium and the sodium carbonate solution and the extraction solvent, and improving the efficiency of impurity removal and extraction; then using the sodium carbonate solution to remove the acidic substances, impurities with properties similar to hesperidin and other water-soluble impurities in the Citrus aurantium powder, and then removing the excess sodium carbonate solution and the residual water-soluble impurities by washing with water; then extracting hesperidin from the washed Citrus aurantium solid by using an extraction solvent (preferably a mixed solution of water+sodium hydroxide+calcium hydroxide), and finally carrying out acid adjustment crystallization, filtering and drying to obtain the hesperidin product.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention first crushes the raw material Citrus aurantium into powder, and uses a crushing process to extract hesperidin, which does not require the use of organic solvents such as ethanol, reduces water consumption, thereby reducing wastewater discharge, and is green and environmentally friendly;

[0042] (2) The present invention does not require cooking, thus saving a large amount of energy such as steam. The present invention only requires simple steps such as crushing-removing impurities-washing-extraction, and integrates and optimizes multiple hesperidin extraction pretreatment technologies to achieve effective extraction of hesperidin. The time for removing impurities and extracting is shortened from the original 48 hours to 2.5-4.0 hours, which greatly simplifies the extraction process, shortens the time for removing impurities and extracting, and has low energy consumption. Without increasing the plant and equipment, the production capacity is multiplied several times. The process is simple, the operability is strong, and it is suitable for industrial production, which opens up a new way for the industrialization of hesperidin extraction. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with specific embodiments.

[0044] Unless otherwise specified, the chemical reagents used in the examples and comparative examples of the present invention were obtained through conventional commercial channels. Example 1

[0045] The method for extracting hesperidin in this embodiment comprises the following steps:

[0046] (1) Crushing: drying the raw material Citrus aurantium (the content of hesperidin in Citrus aurantium is 31%) (controlling the moisture content to 10%), crushing and sieving (10 meshes) to obtain Citrus aurantium powder;

[0047] (2) Removing impurities: 200 kg of the Citrus aurantium powder obtained in step (1) is put into an extraction tank, 5 m³ of Na2CO3 solution is added, and the mixture is stirred to remove impurities (prepared by adding 1 m³ of drinking water to every 4.0 kg of Na2CO3) for 2 hours; the mixture is filtered through a plate and frame filter to obtain a Citrus aurantium powder with impurities removed;

[0048] (3) Washing: Put the wet Citrus aurantium powder obtained in step (2) into an extraction tank, add 2 m³ of water and stir to wash, and stir for 0.5 hours; filter through a plate and frame filter to obtain washed Citrus aurantium powder;

[0049] (4) Extraction: The water-washed and impure Citrus aurantium powder obtained in step (3) is put into an extraction tank, 4 ml of extraction solvent (the extraction solvent is 4 ml of water, 8 kg of sodium hydroxide and 15 kg of calcium hydroxide are added), and the mixture is stirred for extraction for 1 hour; the mixture is filtered through a plate and frame filter to obtain a hesperidin extract;

[0050] (5) Acid adjustment and crystallization: Slowly add 6 mol / L dilute HCl to the extract obtained in step (4) under air pressure stirring, adjust the pH value of the extract to 6.0, and let it stand for 6 hours to obtain an acidified solution containing hesperidin crystals;

[0051] (6) Filtration: the acidified liquid containing hesperidin crystals obtained in step (5) is filtered by a plate and frame filter at a filtration pressure of 0.3 MPa to obtain wet hesperidin crystals;

[0052] (7) Drying: The wet hesperidin crystals obtained in step (6) were placed in an oven and dried at 70° C. for 12 h to obtain 52.7 kg of hesperidin product.

[0053] According to the test, it took only 3.5 hours from impurity removal to obtaining the hesperidin extract in this embodiment, and 11 m³ of water was used. The hesperidin content in the obtained hesperidin product was 90.8%, and the yield was 94.5%. Example 2

[0054] The method for extracting hesperidin in this embodiment comprises the following steps:

[0055] (1) Crushing: drying the raw material Citrus aurantium (the content of hesperidin in Citrus aurantium is 31%) (controlling the moisture content at 10%), crushing and sieving (10 meshes) to obtain Citrus aurantium powder;

[0056] (2) Removing impurities: 200 kg of the Citrus aurantium powder obtained in step (1) was placed in an extraction tank, and 4 mL of Na2CO3 solution was added for stirring to remove impurities (prepared by adding 1 mL of drinking water to every 3.0 kg of Na2CO3) for 1.5 hours; the mixture was filtered through a plate and frame filter to obtain the removed Citrus aurantium powder;

[0057] (3) Washing: the de-impurified Citrus aurantium powder obtained in step (2) is put into an extraction tank, 3 m³ of water is added and stirred for washing, and the mixture is stirred for 0.5 hours; the mixture is filtered through a plate and frame filter to obtain a washed de-impurified Citrus aurantium powder;

[0058] (4) Extraction: The wet Citrus aurantium powder obtained in step (3) is placed in an extraction tank, 5 ml of extraction solvent (the extraction solvent is 5 ml of water, 12 kg of sodium hydroxide and 8 kg of calcium hydroxide are added), and the mixture is stirred for extraction for 1.5 hours; the mixture is filtered through a plate and frame filter to obtain a hesperidin extract;

[0059] (5) Acid adjustment and crystallization: 6 mol / L dilute HCl was slowly added to the extract obtained in step (4) under air pressure stirring, and the pH value of the extract was adjusted to 6.5. The extract was allowed to stand for 6 h to obtain a hesperidin extract acidified solution containing hesperidin crystals;

[0060] (6) Filtration: the hesperidin extract acidified solution containing hesperidin crystals obtained in step (5) is filtered by plate and frame pressure at a filtration pressure of 0.3 MPa to obtain wet hesperidin crystals;

[0061] (7) Drying: The wet hesperidin crystals obtained in step (6) were placed in an oven and dried at 70° C. for 12 h to obtain 51.6 kg of hesperidin product.

[0062] According to the test, it took only 3.5 hours from impurity removal to obtaining the hesperidin extract in this embodiment, and 12 m³ of water was used. The hesperidin content in the obtained hesperidin product was 91.2%, and the yield was 92.5%. Example 3

[0063] The method for extracting hesperidin in this embodiment comprises the following steps:

[0064] (1) Crushing: drying the raw material Citrus aurantium (the content of hesperidin in Citrus aurantium is 31%) (controlling the moisture content to 10%), crushing and sieving (10 meshes) to obtain Citrus aurantium powder;

[0065] (2) Removing impurities: 200 kg of the Citrus aurantium powder obtained in step (1) was placed in an extraction tank, and 4 ml of Na2CO3 solution was added for stirring to remove impurities (prepared by adding 1 ml of drinking water to every 2.0 kg of Na2CO3) for 2 hours; filtered through a plate and frame filter, and the impurity-removed Citrus aurantium powder was obtained by shoveling;

[0066] (3) Washing: the de-impurified Citrus aurantium powder obtained in step (2) is placed in an extraction tank, 2.5 m³ of water is added and stirred for washing for 0.5 hours; filtered through a plate and frame filter to obtain a washed de-impurified Citrus aurantium powder;

[0067] (4) Extraction: The water-washed and impure Citrus aurantium powder obtained in step (3) is put into an extraction tank, and 5 ml of extraction solvent (the extraction solvent is 5 ml of water, 10 kg of sodium hydroxide and 12 kg of calcium hydroxide are added) is stirred for extraction for 1 hour; filtered through a plate and frame filter to obtain a hesperidin extract;

[0068] (5) Acid adjustment and crystallization: 6 mol / L dilute HCl was slowly added to the extract obtained in step (4) under air pressure stirring, and the pH value of the extract was adjusted to 6.5. The extract was allowed to stand for 6 h to obtain a hesperidin extract acidified solution containing hesperidin crystals;

[0069] (6) Filtration: the hesperidin extract acidified solution containing hesperidin crystals obtained in step (5) is filtered by plate and frame pressure at a filtration pressure of 0.3 MPa to obtain wet hesperidin crystals;

[0070] (7) Drying: The wet hesperidin crystals obtained in step (6) were placed in an oven and dried at 70° C. for 12 h to obtain 53.3 kg of hesperidin product.

[0071] According to the test, it took only 3.5 hours from impurity removal to obtaining the hesperidin extract in this embodiment, and 11.5 m³ of water was used. The hesperidin content in the obtained hesperidin product was 90.8%, and the yield was 95.6%. Comparative Example 1

[0072] Comparative Example 1 A method for extracting hesperidin, comprising the following steps:

[0073] (1) Crushing: drying the raw material Citrus aurantium (the content of hesperidin in Citrus aurantium is 31%) (controlling the moisture content to 10%), crushing and sieving (10 meshes) to obtain Citrus aurantium powder;

[0074] (2) Removing impurities: 200 kg of the Citrus aurantium powder obtained in step (1) was put into an extraction tank, and 4 ml of sodium citrate solution was added for stirring and removing impurities (prepared by adding 1 ml of drinking water to every 5.0 kg of sodium citrate) for 5 hours; the solution was filtered through a plate and frame filter, and the impurity-removed Citrus aurantium powder was obtained by shoveling;

[0075] (3) Washing: put the impure-free Citrus aurantium powder obtained in step (2) into an extraction tank, add 2.5 m³ of water and stir for washing, stirring for 0.5 hours; filter through a plate and frame filter, and scrape the washed impure-free Citrus aurantium powder;

[0076] (4) Extraction: The wet Citrus aurantium powder obtained in step (3) is placed in an extraction tank, 5 m³ of extraction solvent (the extraction solvent is 5 m³ of water, 10 kg of sodium hydroxide and 12 kg of calcium hydroxide are added), and the mixture is stirred for extraction for 6 hours; the mixture is filtered through a plate and frame filter to obtain a hesperidin extract;

[0077] (5) Acid adjustment and crystallization: 6 mol / L dilute HCl was slowly added to the extract obtained in step (4) under air pressure stirring, and the pH value of the extract was adjusted to 6.5. The extract was allowed to stand for 6 h to obtain a hesperidin extract acidified solution containing hesperidin crystals;

[0078] (6) Crystallization filtration: The acidified extract obtained in step (5) is filtered by plate and frame pressure at a filtration pressure of 0.3 MPa to obtain wet crystals of hesperidin:

[0079] (7) Drying: The wet hesperidin crystals obtained in step (6) were placed in an oven and dried at 70° C. for 12 h to obtain 51.6 kg of hesperidin product.

[0080] Comparative Example 1 is compared with Example 3, except that the sodium carbonate solution is replaced with a sodium citrate solution.

[0081] After testing, it was found that Comparative Example 1 took 11.5 hours from impurity removal to obtaining the hesperidin extract, and 11.5 m³ of water was used. The hesperidin content in the obtained hesperidin product was 87.8%, which was an unqualified product; the yield was 90.5%. Comparative Example 2

[0082] Comparative Example 2 The method for extracting hesperidin comprises the following steps:

[0083] (1) Crushing: drying the raw material Citrus aurantium (the content of hesperidin in Citrus aurantium is 31%) (controlling the moisture content at 10%), crushing and sieving (10 meshes) to obtain Citrus aurantium powder;

[0084] (2) Removing impurities: 200 kg of the Citrus aurantium powder obtained in step (1) was placed in an extraction tank, and 4 ml of Na2CO3 solution was added for stirring to remove impurities (prepared by adding 1 ml of drinking water to every 2.0 kg of Na2CO3) for 2 hours; the solution was filtered through a plate and frame filter to obtain the removed Citrus aurantium powder;

[0085] (3) Washing: the de-impurified Citrus aurantium powder obtained in step (2) is put into an extraction tank, 2.5 m³ of water is added and stirred for washing for 0.5 hours; the de-impurified Citrus aurantium powder is obtained by shoveling through a plate and frame filter;

[0086] (4) Extraction: The water-washed and impure Citrus aurantium powder obtained in step (3) is put into an extraction tank, and 5 m³ of extraction solvent (the extraction solvent is 5 m³ of water, and 22 kg of sodium hydroxide is added) is stirred for extraction for 1 hour; the mixture is filtered through a plate and frame filter to obtain an extract;

[0087] (5) Acid adjustment and crystallization: 6 mol / L dilute HCl was slowly added to the extract obtained in step (4) under air pressure stirring, and the pH value of the extract was adjusted to 6.5. The extract was allowed to stand for 6 h to obtain an acidified solution of the Citrus aurantium extract;

[0088] (6) Crystallization filtration: The acidified extract obtained in step (5) is filtered by plate and frame pressure at a filtration pressure of 0.3 MPa to obtain wet crystals of hesperidin:

[0089] (7) Drying: The wet hesperidin crystals obtained in step (6) were placed in an oven and dried at 70° C. for 12 h to obtain 54.4 kg of hesperidin product.

[0090] The difference between Comparative Example 2 and Example 3 is that the calcium hydroxide in the extraction solvent is replaced with sodium hydroxide, that is, the extraction solvent used in Comparative Example 2 is: 5m³ water + 22kg sodium hydroxide.

[0091] After testing, it took 3.5 hours from impurity removal to obtaining the extract in Comparative Example 2, and 11.5 m³ of water was used, but the hesperidin content in the obtained hesperidin product was 88.4%, which was an unqualified product; the yield was 91.4%. Since the hesperidin content in the hesperidin product of this comparative example was low, some impurities entered the hesperidin product, and the yield was slightly improved on the surface, but after conversion, the overall yield of the pure hesperidin product was actually lower than that of the embodiment of the present invention.

Claims

1. A method for extracting hesperidin, characterized in that: The following steps are involved: (1) Crushing: drying the raw material of Citrus aurantium, crushing and sieving to obtain Citrus aurantium powder; (2) removing impurities: putting the Fructus Aurantii Immaturus powder obtained in step (1) into an extraction tank, adding sodium carbonate solution and stirring to remove impurities, then separating the solid from the liquid and collecting the solid; the concentration of the sodium carbonate solution is 0.2-0.5wt%; (3) Water washing: the solid obtained in step (2) is placed in an extraction tank, water is added and stirred, washed with water, and then the solid-liquid separation is performed to collect the solid; (4) Extraction: the solid obtained in step (3) is placed in an extraction tank, an extraction solvent is added, stirred, and then the solid-liquid separation is performed, and the extract is collected; the extraction solvent is a mixed solution of water + sodium hydroxide + calcium hydroxide; the extraction solvent is prepared by adding 1m³ of drinking water to every 2.0-4.0kg of NaOH + every 1.5-4.0kg of calcium hydroxide; (5) Acid adjustment and crystallization: adding an acidic reagent to the extract obtained in step (4) under air pressure stirring, adjusting the pH value of the extract to ≤7, and allowing it to stand for crystallization to obtain a hesperidin acidified solution containing hesperidin crystals; (6) filtration, filtering the acidified liquid containing hesperidin wet crystals obtained in step (5) using a filtering device to obtain hesperidin wet crystals; (7) Drying: Drying the wet hesperidin crystals obtained in step (6) to obtain the hesperidin product.

2. The method for extracting hesperidin according to claim 1, characterized in that: In step (1), the drying is to control the moisture content of the Citrus aurantium to be 8-18%; and the pulverizing is to pulverize the Citrus aurantium to a particle size of 10-100 mesh.

3. The method for extracting hesperidin according to claim 1 or 2, characterized in that: In step (2), the amount of sodium carbonate added is 6-15% of the mass of the Citrus aurantium powder, or the amount of the sodium carbonate solution added is 10-30 times the mass of the Citrus aurantium powder.

4. The method for extracting hesperidin according to claim 1 or 2, characterized in that: In step (3), the amount of water added is 10-40 times the mass of the solid obtained in step (2).

5. The method for extracting hesperidin according to claim 3, characterized in that: In step (3), the amount of water added is 10-40 times the mass of the solid obtained in step (2).

6. The method for extracting hesperidin according to claim 1 or 2, characterized in that: In step (4), the amount of water added is 15-30 times the amount of the Citrus aurantium, the amount of sodium hydroxide added is 1-6% of the amount of the Citrus aurantium, and the amount of calcium hydroxide added is 1-10% of the amount of the Citrus aurantium.

7. The method for extracting hesperidin according to claim 3, characterized in that: In step (4), the amount of water added is 15-30 times the amount of the Citrus aurantium, the amount of sodium hydroxide added is 1-6% of the amount of the Citrus aurantium, and the amount of calcium hydroxide added is 1-10% of the amount of the Citrus aurantium.

8. The method for extracting hesperidin according to claim 4, characterized in that: In step (4), the amount of water added is 15-30 times the amount of the Citrus aurantium, the amount of sodium hydroxide added is 1-6% of the amount of the Citrus aurantium, and the amount of calcium hydroxide added is 1-10% of the amount of the Citrus aurantium.

9. The method for extracting hesperidin according to claim 1 or 2, characterized in that: In step (5), the acidic reagent is dilute hydrochloric acid; and the pH value is 5.0-6.

5.

10. The method for extracting hesperidin according to claim 3, characterized in that: In step (5), the acidic reagent is dilute hydrochloric acid; and the pH value is 5.0-6.

5.

11. The method for extracting hesperidin according to claim 4, characterized in that: In step (5), the acidic reagent is dilute hydrochloric acid; and the pH value is 5.0-6.

5.

12. The method for extracting hesperidin according to claim 6, characterized in that: In step (5), the acidic reagent is dilute hydrochloric acid; and the pH value is 5.0-6.

5.

13. The method for extracting hesperidin according to claim 1 or 2, characterized in that: In step (6), the filtering equipment is a plate and frame filter press; the filtration pressure of the plate and frame filter press is ≥0.3Mpa.

14. The method for extracting hesperidin according to claim 3, characterized in that: In step (6), the filtering equipment is a plate and frame filter press; the filtration pressure of the plate and frame filter press is ≥0.3Mpa.

15. The method for extracting hesperidin according to claim 4, characterized in that: In step (6), the filtering equipment is a plate and frame filter press; the filtration pressure of the plate and frame filter press is ≥0.3Mpa.

16. The method for extracting hesperidin according to claim 6, characterized in that: In step (6), the filtering equipment is a plate and frame filter press; the filtration pressure of the plate and frame filter press is ≥0.3Mpa.

17. The method for extracting hesperidin according to claim 9, characterized in that: In step (6), the filtering equipment is a plate and frame filter press; the filtration pressure of the plate and frame filter press is ≥0.3Mpa.

18. The method for extracting hesperidin according to claim 1 or 2, characterized in that: In step (7), the drying temperature is 60-80°C.

19. The method for extracting hesperidin according to claim 3, characterized in that: In step (7), the drying temperature is 60-80°C.

20. The method for extracting hesperidin according to claim 4, characterized in that: In step (7), the drying temperature is 60-80°C.

21. The method for extracting hesperidin according to claim 6, characterized in that: In step (7), the drying temperature is 60-80°C.

22. The method for extracting hesperidin according to claim 9, characterized in that: In step (7), the drying temperature is 60-80°C.

23. The method for extracting hesperidin according to claim 13, characterized in that: In step (7), the drying temperature is 60-80°C.