A method for recovering hesperidin and narirutin from hesperidin crystallization mother liquor

Abstract

The application relates to a method for recovering hesperidin and narirutin from hesperidin crystallization mother liquor, and belongs to the technical field of plant extraction, which comprises the following steps: S1, membrane filtration: hesperidin crystallization mother liquor is sequentially subjected to ceramic membrane and nanofiltration membrane filtration; S2, chromatographic separation: the nanofiltration membrane filtration liquid is subjected to chromatographic separation, 50-95% methanol aqueous solution is used as a gradient elution solvent, and eluate of 1-2 BV and eluate of 3-4 BV are collected respectively; S3, narirutin crystallization: the eluate of 1-2 BV is concentrated to a certain solid content, a crystallization solvent is added to perform cooling crystallization, and product narirutin is obtained; and S4, hesperidin crystallization: the eluate of 3-4 BV is concentrated to a certain solid content, a crystallization solvent is added to perform cooling crystallization, and product hesperidin is obtained. The method for recovering hesperidin and narirutin is simple and convenient, and the yield and content of the recovered product hesperidin and narirutin are high.

Description

Technical Field

[0001] This invention belongs to the field of plant extraction technology, and in particular, it is a method for recovering hesperidin and rutin from hesperidin crystallization mother liquor. Background Technology

[0002] Hesperidin is often used as a pharmaceutical intermediate, which has a protective effect on blood vessels and is used to treat cardiovascular diseases; or as an intermediate in the synthesis of diosmin or other raw materials, and is one of the main components of the traditional Chinese medicine Maitong.

[0003] Naringin can be used as a natural pigment, flavor improver, and bittering agent in the production of food and beverages. It can also be used as a raw material for synthesizing novel sweeteners such as naringin dihydrochalcone and neohesperidin dihydrochalcone. In the pharmaceutical industry, it can be used to produce drugs for the prevention and treatment of cardiovascular and cerebrovascular diseases, analgesia, heat-clearing and anti-inflammatory purposes. It can also be used to prepare a variety of high-value-added organic compounds such as rhamnose, citrate acid azo dyes, and semi-synthetic flavonoids with higher biological activity and medicinal value.

[0004] The current production process for extracting hesperidin is the alkaline extraction and acid precipitation method, which involves extracting hesperidin by ring-opening dissolution under alkaline conditions and separating it by ring-closure precipitation under acidic conditions. This process generates a large amount of wastewater (10-20 tons of wastewater per ton of raw material). The wastewater contains 0.18%-0.30% hesperidin and 0.25%-0.35% rutin, which have not been effectively developed and utilized, resulting in a waste of resources.

[0005] Patent CN111423476A discloses a process for extracting and purifying naringin from bitter orange processing waste liquid. The process mainly involves filtration through a ceramic membrane and purification through a macroporous adsorption resin column twice. In the three examples described in the specification, the content of naringin in the obtained extract products is only 26.1%, 35.4%, and 33.7%, respectively.

[0006] The recovery and utilization of hesperidin and naringin from hesperidin wastewater is of great significance for the comprehensive utilization and development of young citrus fruits. Summary of the Invention

[0007] The purpose of this invention is to provide a method for recovering hesperidin and naringin from hesperidin crystallization mother liquor, overcoming the above-mentioned defects of the prior art. This method is easy to operate and has a high yield and content of hesperidin and naringin.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for recovering hesperidin and naringin from hesperidin crystallization mother liquor includes the following steps:

[0010] Step S1: Membrane filtration: The mother liquor of hesperidin crystallization is then filtered sequentially through a ceramic membrane and a nanofiltration membrane;

[0011] Step S2: Chromatographic separation: The nanofiltration membrane filtrate is subjected to chromatographic separation using a 50-95% methanol aqueous solution as a gradient elution solvent, and the eluents of the 1st-2nd BV and the 3rd-4th BV are collected respectively.

[0012] Step S3: Crystallization of rutin: The eluent from BV 1-2 is concentrated to a certain solid content, and a crystallization solvent is added for cooling and crystallization to obtain the product rutin.

[0013] Step S4: Hesperidin crystallization: The eluent from BV 3-4 is concentrated to a certain solid content, and a crystallization solvent is added for cooling and crystallization to obtain the product hesperidin.

[0014] A further improvement of the technical solution of the present invention is that: the source of the hesperidin crystallization mother liquor in step S1 is the filtrate obtained by soaking, pulverizing and pre-treatment, impurity removal, extraction, pH adjustment, crystallization and filtration of hesperidin raw material. In the pre-treatment process of hesperidin raw material, water is added for soaking for 1-12 hours, and the amount of water added is 0.5-4 times that of the raw material. The wet material is pulverized to a mesh size of 2-40.

[0015] A further improvement of the technical solution of the present invention is that: the impurity removal solution used in the impurity removal step is selected from one or more of sodium citrate solution, sodium carbonate solution and calcium chloride solution, the concentration of the impurity removal solution is 0.1%-2%, the material-to-liquid mass ratio is 1:2-1:8, the impurity removal temperature is 10℃-40℃, and the impurity removal time is 0.5h-4h.

[0016] A further improvement of the technical solution of the present invention is that: the extraction solvent in the extraction step is an aqueous solution of sodium hydroxide, the extraction temperature is 10℃-40℃, the extraction time is 0.5h-4h, the number of extractions is 3-6, and the amount of solvent used in each extraction is 2-20 times that of the raw material; the secondary or tertiary extraction solution is used as the extraction solvent for the next extraction.

[0017] A further improvement to the technical solution of this invention is that the pH value of the hesperidin extract is adjusted to 7-8, and the acid used to adjust the pH is any one of hydrochloric acid, phosphoric acid, or sulfuric acid, followed by standing at 20-35℃ for 6-10 hours.

[0018] A further improvement of the technical solution of the present invention is that: in step S1, the pore size of the ceramic membrane is 5nm-50nm, the filtration temperature is 20-35℃, and the filtration pressure is 0.30±0.10MPa; the molecular weight of the nanofiltration membrane is 700-900, the filtration temperature is 20-35℃, and the filtration pressure is 0.60±0.10MPa.

[0019] A further improvement of the technical solution of the present invention is that: the chromatographic column used for chromatographic separation in step S2 is a silica gel column, and the gradient elution is performed using a methanol aqueous solution with a volume fraction of 75%-85% and 90%-95%.

[0020] A further improvement of the technical solution of the present invention is that: in step S2, the gradient elution is first eluted with a methanol aqueous solution with a volume fraction of 75%-85% and the eluent of the first 1-2 BV is collected; then eluted with a methanol aqueous solution with a volume fraction of 90-95% and the eluent of the third 3-4 BV is collected.

[0021] A further improvement of the technical solution of the present invention is that: in step S3, vacuum concentration is carried out at 50°C until the solid content of the concentrated liquid is 30%-60%, and the cooling curve is used to cool from 50°C to 15-30°C at 5-7°C / h. 5%-10% petroleum ether is added, and the liquid is kept at 15-30°C for 2 hours. The liquid is then cooled to 0-10°C at 5-7°C / h and kept for 6-10 hours.

[0022] A further improvement of the technical solution of the present invention is that: in step S4, the liquid is concentrated under vacuum at 50°C to a solid content of 25%-50%, and the temperature is lowered from 50°C to 20-30°C at a rate of 4-8°C / h. 3%-12% petroleum ether is added, and the liquid is kept at 20-30°C for 2 hours. The liquid is then lowered to 0-10°C at a rate of 4-8°C / h and kept for 8-15 hours.

[0023] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are as follows:

[0024] This invention first adjusts the pH of the hesperidin extract to 7-8 to obtain a hesperidin mother liquor. Inorganic salts and sugars are removed using a ceramic membrane and nanofiltration membrane. Hesperidin and rutin are separated from the membrane permeate by chromatography. A gradient elution with methanol and aqueous solution yields an eluent containing hesperidin and rutin, which is then concentrated to a certain solid content and subjected to cooling crystallization to obtain high-content hesperidin and rutin. The addition of petroleum ether solvent and control of the cooling curve ensure that the crystal size of hesperidin and rutin is ≥22.4 μm. The hesperidin yield recovered from the hesperidin crystallization mother liquor using this method is ≥98%, with a content ≥96%; the rutin yield is ≥95%, with a content ≥96%. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to embodiments:

[0026] Example 1

[0027] Taking the extraction of 1000 kg of young citrus fruit (hesperidin content 22.5%, rutin 3.0%) as an example, the method for simultaneously recovering hesperidin and rutin from the mother liquor of hesperidin crystallization is described in detail.

[0028] (1) Soak 1000kg of Citrus aurantium raw material in 1000kg of water for 2 hours, grind the wet material into 5 mesh, divide it into 5 groups for extraction, each group is 200kg.

[0029] (2) Add impurity removal solution to the pretreated raw material and remove impurities at 25°C. The impurity removal solution is a 0.4% sodium carbonate solution. The amount of impurity removal solution is 4 times that of the raw material. The impurity removal time is 2 hours. Then, perform plate and frame filtration to obtain the impurity removed material.

[0030] (3) Extraction: Add 0.4% sodium hydroxide solution to the impurity-removed material for extraction. Extract 4 times at 25℃ for 2 hours each time. The amount of extraction solvent used is 5 times that of the raw material. The second extraction solution is used as the solvent for the first extraction in the next batch for cyclic extraction to obtain hesperidin extract.

[0031] (4) Hesperidin mother liquor: Add hydrochloric acid to the hesperidin extract to adjust the pH of the extract to 7.5, let it stand at 25℃ for 8 hours, and then filter it through a plate and frame filter to obtain the hesperidin product and the hesperidin mother liquor.

[0032] (5) Membrane filtration: The hesperidin mother liquor was filtered through a 25nm ceramic membrane at a temperature of 30℃ and a pressure of 0.29MPa. The ceramic membrane filtrate was filtered through a 700-900 molecular weight nanofiltration membrane at a temperature of 30℃ and a pressure of 0.64MPa.

[0033] (6) Chromatographic separation: The nanofiltration membrane filtrate was chromatographically separated. It was washed with 2 BV of 60% (volume) methanol aqueous solution, eluted with 80% methanol aqueous solution and collected the first 2 BV of eluent, and eluted with 92% methanol aqueous solution and collected the third 4 BV of eluent.

[0034] (7) Crystallization of rutin: The eluent of the first-second batch of 1-2 batches was concentrated at 50°C to a solid content of 40%. The cooling curve was changed from 50°C to 20°C at a rate of 5°C / h. 6% petroleum ether was added and the mixture was kept at 20°C for 2 hours. The mixture was then cooled to 8°C at a rate of 5°C / h and kept at 8 hours to obtain the product rutin, with a content of 96.8%, a yield of 95.19%, and a crystal particle size of 22.8 μm.

[0035] (8) Hesperidin crystallization: The eluent from the 3rd-4th BV was concentrated at 50°C to a solid content of 30%. The cooling curve was from 50°C to 22°C at a rate of 6°C / h. 4% petroleum ether was added and the mixture was kept at 22°C for 2 hours. The mixture was then cooled to 5°C at a rate of 6°C / h and kept at 5°C for 10 hours to obtain the hesperidin product with a content of 97.6% and a total yield of 98.3%. The crystal particle size was 22.4 μm.

[0036] Example 2

[0037] 1000kg of young citrus fruit (hesperidin content 22.5%, rutin content 3.0%)

[0038] (1) Soak 1000kg of Citrus aurantium raw material in 1000kg of water for 2 hours, grind the wet material into 5 mesh, divide it into 5 groups for extraction, each group is 200kg.

[0039] (2) Add impurity removal solution to the pretreated raw material and remove impurities at 25°C. The impurity removal solution is 0.5% sodium citrate solution. The amount of impurity removal solution is 3 times that of the raw material. The impurity removal time is 2 hours.

[0040] (3) Extraction: Add 0.4% sodium hydroxide solution to the impurity-removed material for extraction. Extract 4 times at 30℃ for 1.5 hours each time. The amount of extraction solvent used is 4 times that of the raw material. The second extraction solution is used as the solvent for the first extraction in the next batch for cyclic extraction to obtain hesperidin extract.

[0041] (4) Hesperidin mother liquor: Add hydrochloric acid to the hesperidin extract to adjust the pH of the extract to 7.0, let it stand at 25℃ for 8 hours, and then filter it through a plate and frame filter to obtain the hesperidin product and the hesperidin mother liquor.

[0042] (5) Membrane filtration: The hesperidin mother liquor was filtered through a 25nm ceramic membrane at a temperature of 30℃ and a pressure of 0.29MPa. The ceramic membrane filtrate was filtered through a 700-900 molecular weight nanofiltration membrane at a temperature of 30℃ and a pressure of 0.64MPa.

[0043] (6) Chromatographic separation: The nanofiltration membrane filtrate was subjected to chromatographic separation. Impurities were washed with 2 BV of 60% (volume) methanol aqueous solution, and the eluent of 1-2 BV was collected by elution with 78% methanol aqueous solution. The eluent of 3-4 BV was collected by elution with 93% methanol aqueous solution.

[0044] (7) Crystallization of rutin: The eluent of the first-second batch of 1-2 batches was concentrated at 50°C to a solid content of 35%. The cooling curve was changed from 50°C to 25°C at a rate of 6°C / h. 6% petroleum ether was added and the mixture was kept at 25°C for 2 hours. The mixture was then cooled to 10°C at a rate of 6°C / h and kept at 10°C for 8 hours to obtain the product rutin, with a content of 96.5%, a yield of 95.39%, and a crystal particle size of 23.5 μm.

[0045] (8) Hesperidin crystallization: The 3rd-4th BV eluent was concentrated at 50°C to a solid content of 34%. The cooling curve was from 50°C to 20°C at a rate of 5°C / h. 4% petroleum ether was added and the mixture was kept at 20°C for 2 hours. The mixture was then cooled to 5°C at a rate of 5°C / h and kept at 5°C for 10 hours to obtain the hesperidin product with a content of 98.2% and a total yield of 98.4%. The crystal particle size was 23.4 μm.

[0046] Example 3

[0047] 1000kg of young citrus fruit (hesperidin content 22.5%, rutin content 3.0%)

[0048] (1) Soak 1000kg of Citrus aurantium raw material in 1000kg of water for 2 hours, grind the wet material into 5 mesh, divide it into 5 groups for extraction, each group is 200kg.

[0049] (2) Add impurity removal solution to the pretreated raw material and remove impurities at 25°C. The impurity removal solution is 0.5% sodium citrate solution. The amount of impurity removal solution is 3 times that of the raw material. The impurity removal time is 2 hours.

[0050] (3) Extraction: Add 0.4% sodium hydroxide solution to the impurity-removed material for extraction. Extract 4 times at 30℃ for 1.5 hours each time. The amount of extraction solvent used is 4 times that of the raw material. The second extraction solution is used as the solvent for the first extraction in the next batch for cyclic extraction to obtain hesperidin extract.

[0051] (4) Hesperidin mother liquor: Add hydrochloric acid to the hesperidin extract to adjust the pH of the extract to 8.0, let it stand at 25°C for 8 hours, and then filter it through a plate and frame filter to obtain the hesperidin product and the hesperidin mother liquor.

[0052] (5) Membrane filtration: The hesperidin mother liquor was filtered through a 25nm ceramic membrane at a temperature of 30℃ and a pressure of 0.29MPa. The ceramic membrane filtrate was filtered through a 700-900 molecular weight nanofiltration membrane at a temperature of 30℃ and a pressure of 0.64MPa.

[0053] (6) Chromatographic separation: The nanofiltration membrane filtrate was subjected to chromatographic separation using a C18 column. 2 BV of 60% (volume) methanol aqueous solution was used for washing, followed by elution with 77% methanol aqueous solution to collect the first 2 BV of eluent, and then elution with 91% methanol aqueous solution to collect the third 4 BV of eluent.

[0054] (7) Crystallization of rutin: The eluent of the first-second batch of 1-2 batches was concentrated at 50°C to a solid content of 38%. The cooling curve was changed from 50°C to 23°C at a rate of 6°C / h. 6% petroleum ether was added and the mixture was kept at 23°C for 2 hours. The mixture was then cooled to 10°C at a rate of 6°C / h and kept at 10°C for 8 hours to obtain the product rutin, with a content of 96.7%, a yield of 95.55%, and a crystal particle size of 23.7 μm.

[0055] (8) Hesperidin crystallization: The eluent from the 3rd-4th BV was concentrated at 50°C to a solid content of 37%. The cooling curve was from 50°C to 20°C at a rate of 5°C / h. 4% petroleum ether was added and the mixture was kept at 20°C for 2 hours. The mixture was then cooled to 7°C at a rate of 5°C / h and kept at 7°C for 10 hours to obtain the hesperidin product with a content of 98.4% and a total yield of 98.5%. The crystal particle size was 23.3 μm.

[0056] Comparative Example 1

[0057] Extracted from 1000 kg of young citrus fruits (hesperidin content 22.5%, rutin content 3.0%).

[0058] (1) Soak 1000kg of Citrus aurantium raw material in 1000kg of water for 2 hours, grind the wet material into 5 mesh, divide it into 5 groups for extraction, each group is 200kg.

[0059] (2) Add impurity removal solution to the pretreated raw material and remove impurities at 25°C. The impurity removal solution is a 0.4% sodium carbonate solution. The amount of impurity removal solution is 4 times that of the raw material. The impurity removal time is 2 hours.

[0060] (3) Extraction: Add 0.4% sodium hydroxide solution to the impurity-removed material for extraction. Extract 4 times at 25℃ for 2 hours each time. The amount of extraction solvent used is 5 times that of the raw material. The second extraction solution is used as the solvent for the first extraction in the next batch for cyclic extraction to obtain hesperidin extract.

[0061] (4) Crystallization: Add hydrochloric acid to the hesperidin extract to adjust the pH of the extract to 4.5, let it stand at 25℃ for 8 hours, and then filter it through a plate and frame filter to obtain the hesperidin product and the hesperidin mother liquor. The product contains 89.58% hesperidin and 6.57% rutin.

[0062] (5) Membrane filtration: The hesperidin mother liquor was filtered through a 25nm ceramic membrane at a temperature of 30℃ and a pressure of 0.29MPa. The ceramic membrane filtrate was filtered through a 700-900 molecular weight nanofiltration membrane at a temperature of 30℃ and a pressure of 0.64MPa.

[0063] (6) Chromatographic separation: The nanofiltration membrane filtrate was chromatographically separated. It was washed with 2 BV of 60% (volume) methanol aqueous solution, eluted with 80% methanol aqueous solution and collected the first 2 BV of eluent, and eluted with 92% methanol aqueous solution and collected the third 4 BV of eluent.

[0064] (7) Crystallization of rutin: The eluent of the first-second batch of 1-2 batches was concentrated at 50°C to a solid content of 40%. The cooling curve was changed from 50°C to 20°C at a rate of 5°C / h. 6% petroleum ether was added and the mixture was kept at 20°C for 2 hours. The mixture was then cooled to 8°C at a rate of 5°C / h and kept at 8 hours to obtain the product rutin, with a content of 75.8%, a yield of 45.19%, and a crystal particle size of 22.1 μm.

[0065] (8) Hesperidin crystallization: The eluent from the 3rd-4th BV was concentrated at 50°C to a solid content of 37%. The temperature was lowered from 50°C to 20°C at a rate of 5°C / h. 4% petroleum ether was added and the temperature was maintained at 20°C for 2 hours. The temperature was then lowered to 7°C at a rate of 5°C / h and maintained for 10 hours to obtain the hesperidin product with a content of 98.3% and a total yield of 98.1%. The crystal particle size was 23.5 μm.

[0066] Comparative Example 2

[0067] Extracted from 1000 kg of young citrus fruits (hesperidin content 22.5%, rutin content 3.0%).

[0068] (1) Soak 1000kg of Citrus aurantium raw material in 1000kg of water for 2 hours, grind the wet material into 5 mesh, divide it into 5 groups for extraction, each group is 200kg.

[0069] (2) Add impurity removal solution to the pretreated raw material and remove impurities at 25°C. The impurity removal solution is a 0.4% sodium carbonate solution. The amount of impurity removal solution is 4 times that of the raw material. The impurity removal time is 2 hours.

[0070] (3) Extraction: Add 0.4% sodium hydroxide solution to the impurity-removed material for extraction. Extract 4 times at 25℃ for 2 hours each time. The amount of extraction solvent used is 5 times that of the raw material. The second extraction solution is used as the solvent for the first extraction in the next batch for cyclic extraction to obtain hesperidin extract.

[0071] (4) Hesperidin mother liquor: Add hydrochloric acid to the hesperidin extract to adjust the pH value of the extract to 8.5, let it stand at 25℃ for 8 hours, and then filter it through a plate and frame filter to obtain the hesperidin mother liquor.

[0072] (5) Membrane filtration: The hesperidin mother liquor was filtered through a 25nm ceramic membrane at a temperature of 30℃ and a pressure of 0.29MPa. The ceramic membrane filtrate was filtered through a 700-900 molecular weight nanofiltration membrane at a temperature of 30℃ and a pressure of 0.64MPa.

[0073] (6) Chromatographic separation: The nanofiltration membrane filtrate was chromatographically separated. It was washed with 2 BV of 60% (volume) methanol aqueous solution, eluted with 80% methanol aqueous solution and collected the first 2 BV of eluent, and eluted with 92% methanol aqueous solution and collected the third 4 BV of eluent.

[0074] (7) Crystallization of rutin: The eluent of the first-second batch of 1-2 batches was concentrated at 50°C to a solid content of 40%. The cooling curve was changed from 50°C to 20°C at a rate of 5°C / h. 6% petroleum ether was added and the mixture was kept at 20°C for 2 hours. The mixture was then cooled to 8°C at a rate of 5°C / h and kept at 8 hours to obtain the product rutin, with a content of 93.3%, a yield of 92.19%, and a crystal particle size of 22.1 μm.

[0075] (8) Hesperidin crystallization: The 3rd-4th BV eluent was concentrated at 50°C to a solid content of 30%. The cooling curve was from 50°C to 22°C at 6°C / h. 4% petroleum ether was added and kept at 22°C for 2h. The temperature was then reduced to 5°C at 6°C / h and kept for 10h to obtain the hesperidin product with a content of 93.6%, a total yield of 94.3%, and a crystal particle size of 22.8μm.

[0076] Comparative Example 3

[0077] Extracted from 1000 kg of young citrus fruits (hesperidin content 22.5%, rutin content 3.0%).

[0078] (1) Soak 1000kg of Citrus aurantium raw material in 1000kg of water for 2 hours, grind the wet material into 5 mesh, divide it into 5 groups for extraction, each group is 200kg.

[0079] (2) Add impurity removal solution to the pretreated raw material and remove impurities at 25°C. The impurity removal solution is a 0.4% sodium carbonate solution. The amount of impurity removal solution is 4 times that of the raw material. The impurity removal time is 2 hours.

[0080] (3) Extraction: Add 0.4% sodium hydroxide solution to the impurity-removed material for extraction. Extract 4 times at 25℃ for 2 hours each time. The amount of extraction solvent used is 5 times that of the raw material. The second extraction solution is used as the solvent for the first extraction in the next batch for cyclic extraction to obtain hesperidin extract.

[0081] (4) Hesperidin mother liquor: Add hydrochloric acid to the hesperidin extract to adjust the pH value of the extract to 6.5, let it stand at 25℃ for 8 hours, and then filter it through a plate and frame filter to obtain the hesperidin product and the hesperidin mother liquor; the product has a hesperidin content of 93.28% and a rutin content of 3.57%.

[0082] (5) Membrane filtration: The hesperidin mother liquor was filtered through a 25nm ceramic membrane at a temperature of 30℃ and a pressure of 0.29MPa. The ceramic membrane filtrate was filtered through a 700-900 molecular weight nanofiltration membrane at a temperature of 30℃ and a pressure of 0.64MPa.

[0083] (6) Chromatographic separation: The nanofiltration membrane filtrate was chromatographically separated. It was washed with 2 BV of 60% (volume) methanol aqueous solution, eluted with 80% methanol aqueous solution and collected the first 2 BV of eluent, and eluted with 92% methanol aqueous solution and collected the third 4 BV of eluent.

[0084] (7) Crystallization of rutin: The eluent of the first-second batch of 1-2 batches was concentrated at 50°C to a solid content of 40%. The cooling curve was changed from 50°C to 20°C at a rate of 5°C / h. 6% petroleum ether was added and the mixture was kept at 20°C for 2 hours. The mixture was then cooled to 8°C at a rate of 5°C / h and kept at 8 hours to obtain the product rutin, with a content of 86.8%, a yield of 75.49%, and a crystal particle size of 22.5 μm.

[0085] (8) Hesperidin crystallization: The eluent from the 3rd-4th BV was concentrated at 50°C to a solid content of 30%. The cooling curve was changed from 50°C to 22°C at a rate of 6°C / h. 4% petroleum ether was added and the mixture was kept at 22°C for 2 hours. The mixture was then cooled to 5°C at a rate of 6°C / h and kept at 5°C for 10 hours to obtain the hesperidin product with a content of 95.6%, a total yield of 94.9%, and a crystal particle size of 22.9 μm.

[0086] The chromatographic columns used for chromatographic separation in the above embodiments and comparative examples are large silica columns, specifically C18 silica columns.

[0087] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for recovering hesperidin and naringin from hesperidin crystallization mother liquor, characterized in that... Includes the following steps: Step S1: Membrane filtration: The mother liquor of hesperidin crystallization is filtered sequentially through a ceramic membrane and a nanofiltration membrane; Step S2: Chromatographic separation: The nanofiltration membrane filtrate is subjected to chromatographic separation using a 50-95% methanol aqueous solution as a gradient elution solvent, and the eluents of the 1st-2nd BV and the 3rd-4th BV are collected respectively. Step S3: Crystallization of rutin: The eluent from BV 1-2 is concentrated to a certain solid content, and a crystallization solvent is added for cooling and crystallization to obtain the product rutin. Step S4: Hesperidin crystallization: The eluent from BV 3-4 is concentrated to a certain solid content, and a crystallization solvent is added for cooling and crystallization to obtain the product hesperidin; In step S1, the hesperidin crystallization mother liquor is the filtrate obtained by soaking, pulverizing, pre-treatment, impurity removal, extraction, pH adjustment, crystallization, and filtration of hesperidin raw material. In the pre-treatment process of hesperidin raw material, water is added for soaking for 1-12 hours, and the amount of water added is 0.5-4 times that of the raw material. The wet material is pulverized to a mesh size of 2-40. The chromatographic separation in step S2 is performed using a silica gel column, with gradient elution consisting of first elution with a 75%-85% (v / v) methanol-water solution and collection of the first 1-2 BV of eluent; then elution with a 90-95% (v / v) methanol-water solution and collection of the third-4 BV of eluent. In step S3, the liquid is concentrated under vacuum at 50°C to a solid content of 30%-60%. The temperature is lowered from 50°C to 15-30°C at a rate of 5-7°C / h. 5%-10% petroleum ether is added and the liquid is kept at 15-30°C for 2 hours. The liquid is then lowered to 0-10°C at a rate of 5-7°C / h and kept at 0-10°C for 6-10 hours. In step S4, the liquid is concentrated under vacuum at 50°C to a solid content of 25%-50%. The temperature is then lowered from 50°C to 20-30°C at a rate of 4-8°C / h. 3%-12% petroleum ether is added, and the liquid is kept at 20-30°C for 2 hours. The temperature is then lowered to 0-10°C at a rate of 4-8°C / h and kept for 8-15 hours.

2. The method for recovering hesperidin and naringin from hesperidin crystallization mother liquor according to claim 1, characterized in that: The impurity removal solution used in the impurity removal step is selected from one or more of sodium citrate solution, sodium carbonate solution and calcium chloride solution. The concentration of the impurity removal solution is 0.1%-2.0%, the impurity removal temperature is 10℃-40℃, and the impurity removal time is 0.5h-4h.

3. The method for recovering hesperidin and naringin from hesperidin crystallization mother liquor according to claim 1, characterized in that: The extraction solvent is sodium hydroxide aqueous solution, the extraction temperature is 10℃-40℃, the extraction time is 0.5h-4h, the extraction is performed 3-6 times, and the amount of solvent used in each extraction is 2-20 times that of the raw material; the second or third extraction solution is used as the extraction solvent for the next extraction.

4. The method for recovering hesperidin and naringin from hesperidin crystallization mother liquor according to claim 1, characterized in that: Adjust the pH of the hesperidin extract to 7-8. The acid used to adjust the pH is any one of hydrochloric acid, phosphoric acid, or sulfuric acid. Then let it stand at 20-35℃ for 6-10 hours.

5. The method for recovering hesperidin and naringin from hesperidin crystallization mother liquor according to claim 1, characterized in that: In step S1, the ceramic membrane has a pore size of 5nm-50nm, a filtration temperature of 20-35℃, and a filtration pressure of 0.30±0.10MPa; the nanofiltration membrane has a molecular weight of 700-900, a filtration temperature of 20-35℃, and a filtration pressure of 0.60±0.10MPa.