Process and equipment for purifying aronia melanocarpa anthocyanin

Abstract

The invention discloses an aronia melanocarpa anthocyanin purification process and equipment. The process comprises the following steps: pretreating and crushing raw materials to prepare fruit powder, mixing the fruit powder with an acidic solvent, introducing inert gas for ultrasonic extraction, and carrying out graded filtration and low-temperature concentration on an extracting solution to obtain a crude extract concentrated solution; magnetic macroporous adsorption resin is regulated and controlled through a gradient magnetic field to form a uniform bed layer, a concentrated solution is subjected to chromatographic adsorption, and then a finished product is obtained through gradient elution, secondary concentration, two-phase extraction, drying and stabilizing treatment. By means of the magnetic resin and gradient magnetic control design, the anthocyanin adsorption efficiency and separation precision are improved, the product purity and activity retention rate are improved, and the large-scale production requirement is met.

Description

Technical Field

[0001] This invention relates to the field of anthocyanin purification technology, and in particular to a process and equipment for purifying anthocyanins from *Aristolochia debilis*. Background Technology

[0002] Aronia berries are rich in anthocyanins and other polyphenolic active ingredients, and their purification process has become a research hotspot in the food and health product fields. Currently, the mainstream purification technology in industry is the macroporous adsorption resin fixed-bed process. This process separates anthocyanins from impurities through a process of "raw material pretreatment - ultrasonic extraction - membrane filtration - fixed-bed resin adsorption - gradient elution - concentration and drying". Due to its advantages such as simple operation, controllable cost, and easy scalability, it is widely used in industrial production.

[0003] Among them, macroporous adsorption resins have become the core purification medium due to their high adsorption selectivity for anthocyanins. Their adsorption mechanism mainly relies on the hydrophobic effect, van der Waals force and hydrogen bonding of the resin pores to achieve the enrichment of anthocyanins and the removal of impurities.

[0004] However, in existing technologies, fixed-bed resin columns rely on gravity to fill the column with resin particles. During the natural settling process, localized dense areas and voids are easily formed. In the dense areas, the resin is tightly packed, resulting in high resistance to the flow of the liquid. In the void areas, the resistance is low, causing the liquid to preferentially flow rapidly along the voids, forming "channeling." This phenomenon prevents some resin from fully contacting the liquid, creating adsorption "dead zones" and wasting a large number of adsorption sites. Furthermore, anthocyanins in the "channeling" areas do not have sufficient contact time with the resin and are not fully adsorbed before leaking out with the effluent, resulting in the problem of "premature breakthrough." Summary of the Invention

[0005] The main objective of this invention is to provide a purification process and equipment for anthocyanins from *Aristolochia debilis*. By customizing magnetic adsorption resins, designing gradient magnetron chromatography, and innovating the structure of specialized equipment, this invention achieves efficient adsorption and precise separation of anthocyanins, improves product purity and activity retention, simplifies the resin recovery process, enhances equipment operational stability, and meets the needs of large-scale production.

[0006] To achieve the above objectives, this invention proposes a purification process for anthocyanins from *Aristolochic acid*, comprising the following steps: S100. Raw material pretreatment and crushing: The aronia berry raw material is screened, washed, crushed, degreased, dried and crushed in sequence to obtain aronia berry powder; S200. Extraction: The aronia berry powder is mixed with an acidic extraction solvent, and an inert gas is introduced to form a protective atmosphere before ultrasonic-assisted extraction is performed to obtain an extract. S300, graded filtration: The extract is subjected to coarse filtration and fine filtration in sequence to remove solid impurities and macromolecular colloids, and the permeate is collected; S400, Low-temperature concentration: The permeate is concentrated at low temperature to obtain a crude concentrate; S500, Magnetic Field Controlled Chromatographic Purification: A magnetic macroporous adsorption resin is prepared, and then the magnetic macroporous adsorption resin is packed between two supporting sieve plates in the chromatography column. A gradient magnetic field that increases along the flow direction of the feed liquid is generated by a magnetic field control device, driving the magnetic macroporous adsorption resin particles to locally fine-tune their positions and form a uniform fixed phase bed. The crude extract concentrate is then passed into the chromatography column at a gradient flow rate that decreases along the flow direction of the feed liquid to complete the anthocyanin adsorption. S600, gradient elution: The chromatography column is sequentially eluted with deionized water, low-concentration ethanol solution and high-concentration ethanol solution, and the anthocyanin enriched eluent is collected. S700, Refining process: The anthocyanin enrichment eluent is subjected to secondary concentration, two-phase extraction for impurity removal, drying and shaping, and stabilization treatment to obtain the finished anthocyanin product of *Ipomoea purpurea*.

[0007] In one possible implementation, the preparation steps of the magnetic macroporous adsorption resin in step S500 are as follows: S510, Matrix pretreatment: Take macroporous adsorption resin, soak it in 95% ethanol by volume to activate it, wash it with deionized water until neutral and vacuum dry it. S520, In-situ loading of magnetic nuclei: The pretreated macroporous adsorption resin is dispersed in deionized water to form a suspension. A mixed solution of ferrous sulfate and ferric chloride is added, wherein the molar ratio of ferrous ions to ferric ions is 1:2. Ammonia water is added dropwise to adjust the pH to alkaline, and then the temperature is raised and kept warm, so that the magnetite magnetic nuclei are deposited in-situ on the resin surface and in the pores. S530, Isolation layer coating: Add silane coupling agent to the suspension and heat the reaction to form a silicon dioxide isolation layer on the surface of the magnetite core; S540, Post-treatment: Separate the resin, wash it with water until neutral and dry it to obtain magnetic macroporous adsorption resin.

[0008] In one possible implementation, in step S520, the total mass of the mixed solution is 15%-25% of the mass of the macroporous adsorption resin; in step S530, the amount of the silane coupling agent is 3%-8% of the mass of the macroporous adsorption resin, and it is added after being diluted with ethanol beforehand.

[0009] In one possible implementation, in step S500, the gradient magnetic field is formed by two independent magnetic field generating units arranged along the axial direction of the chromatography column; the gradient flow rate is inversely adapted to the magnetic field strength gradient to achieve full adsorption of anthocyanins of different molecular weights.

[0010] In one possible implementation, in step S600, the volume fraction of the low-concentration ethanol solution is 15%-25%, and the volume fraction of the high-concentration ethanol solution is 65%-75%; during the elution process, the elution flow rates of deionized water, low-concentration ethanol solution, and high-concentration ethanol solution decrease sequentially.

[0011] An aralia elata anthocyanin purification device is used to achieve the above-mentioned purification process. It includes a magnetron chromatography device, and a raw material processing device, an ultrasonic extraction device, a grading filter device, a low-temperature concentration device, a gradient rinsing device, and a refining and collecting device, which are sequentially flange-connected to the magnetron chromatography device via sealed feed pipelines. The housings of each device are made of corrosion-resistant metal, and sealing gaskets are provided at the interfaces between the sealed feed pipelines and each device. It also includes an integrated control box, which is electrically connected to the actuators of each device via cables. The magnetron chromatography device has a sealed chamber inside for filling with magnetic macroporous adsorption resin.

[0012] In one possible implementation, the magnetron chromatography apparatus includes a chromatography column, an upper sieve plate assembly, and a lower sieve plate assembly; the chromatography column is a hollow cylinder with flanges at both ends; the upper sieve plate assembly includes an upper sieve plate body, which is a porous plate structure, fixedly connected to the inner wall of the chromatography column and detachably mounted; the lower sieve plate assembly includes a fixed sieve plate, a movable sieve plate, and a lifting support rod; the fixed sieve plate is disposed in the middle of the chromatography column, forming a leakage gap between it and the inner wall of the chromatography column; the movable sieve plate is slidably disposed inside the chromatography column and connected to the lifting support rod; the movable sieve plate and the fixed sieve plate can be joined together to close the leakage gap.

[0013] In one possible implementation, the magnetron chromatography apparatus further includes a gradient magnetron control assembly, which comprises at least two magnetic coil units. Each magnetic coil unit includes an insulating frame, an enameled coil, and a terminal block. The insulating frame is a cylindrical structure fitted onto the outer wall of the chromatography column. The enameled coil is wound around the outside of the insulating frame, and the terminal block is fixed to the end of the insulating frame and electrically connected to the enameled coil. Along the axial direction of the chromatography column from the feed end to the discharge end, the number of turns of the enameled coil in each magnetic coil unit increases sequentially, and each magnetic coil unit is covered with a magnetic shield.

[0014] In one possible implementation, the magnetron chromatography apparatus further includes a temperature control component and a discharge hopper; the temperature control component includes a spiral heat exchange tube fixed inside the chromatography column, with its inlet and outlet located at the lower and upper sides respectively; it also includes a temperature probe installed inside the chromatography column; the discharge hopper has a conical structure, with its large-diameter end sealed to the bottom flange of the chromatography column, and its small-diameter end equipped with a discharge pipe with a pneumatic valve, the discharge pipe being connected to the sealed conveying pipeline flange of the refining and receiving device.

[0015] In one possible implementation, the magnetron chromatography apparatus further includes a gas-assisted discharge assembly, which includes an airflow pipe and a control valve group. One end of the airflow pipe is obliquely connected to the side wall of the discharge hopper and communicates with the inside of the discharge hopper, while the other end is connected to a high-pressure gas source. The control valve group includes an electromagnetic shut-off valve and a flow regulating valve, which are connected in series on the airflow pipe, and the electromagnetic shut-off valve is electrically connected to an integrated control box via a cable. The lower end of the lifting support rod is connected to a drive cylinder, and the drive cylinder and the electromagnetic shut-off valve are linked and controlled by the integrated control box.

[0016] In summary, the beneficial effects of this application are as follows: 1. Magnetic macroporous adsorption resin has a high adsorption capacity. With the reverse adaptation of gradient magnetic field and gradient flow rate, the resin forms a uniform bed, realizing precise separation of anthocyanins, reducing adsorption blind zone, and improving adsorption efficiency and separation accuracy.

[0017] 2. Step-by-step impurity removal through graded filtration and gradient elution, low-temperature concentration and stabilization treatment reduce anthocyanin degradation, significantly improving product purity and activity retention rate.

[0018] 3. The silica isolation layer protects the magnetic core and can be combined with the screen plate and air-assisted discharge assembly to achieve rapid resin aggregation and discharge, reducing residue; it is convenient to regenerate, extends the service life of the resin, and saves costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a flowchart of Embodiment 1 of the present invention; Figure 2 This is a device connection block diagram for Embodiment 3; Figure 3 This is a schematic diagram showing the connection between the chromatography column and the equipment in Embodiment 3 of the present invention; Figure 4 This is a cross-sectional view of the chromatography column of Embodiment 3 of the present invention; Figure 5 This is a structural diagram of the upper sieve plate assembly in Embodiment 3 of the present invention; Figure 6 This is a structural diagram of the lower sieve plate assembly in Embodiment 3 of the present invention; Explanation of icon numbers: 1. Chromatography column; 2. Upper sieve plate assembly; 20. Upper sieve plate body; 3. Lower sieve plate assembly; 30. Fixed sieve plate; 31. Movable sieve plate; 32. Lifting support rod; 33. Material leakage gap; 34. Drive cylinder; 4. Gradient magnetic control assembly; 40. Insulating frame; 41. Enamelled coil; 42. Magnetic shielding cover; 5. Temperature control assembly; 50. Heat exchange tube; 51. Temperature probe; 6. Discharge hopper; 7. Pneumatic valve; 8. Discharge pipe; 9. Airflow connection pipe; 10. Upper support ring; 11. Lower support ring; 12. Connecting rod; 13. Connecting rod.

[0021] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] Example 1 like Figure 1 As shown, this invention proposes a purification process for aronia berry anthocyanins, which includes the following steps: S100. Raw material pretreatment and crushing: The aronia berry raw material is screened, washed, crushed, degreased, dried and crushed in sequence to obtain aronia berry powder; S200. Extraction: The aronia berry powder is mixed with an acidic extraction solvent, and an inert gas is introduced to form a protective atmosphere before ultrasonic-assisted extraction is performed to obtain an extract. S300, graded filtration: The extract is subjected to coarse filtration and fine filtration in sequence to remove solid impurities and macromolecular colloids, and the permeate is collected; S400, Low-temperature concentration: The permeate is concentrated at low temperature to obtain a crude concentrate; The above S100-S400 processes are all existing extraction processes for anthocyanins from bromelain, specifically: In the raw material pretreatment and crushing stage, the aronia berries are first screened using a vibrating screen with a 10 mm aperture. The vibration of the screen separates fruits with uniform ripeness and a deep purple color, while removing impurities such as branches, leaves, stones, and rotten fruit. This step ensures the quality of the raw materials from the source, preventing inferior raw materials from affecting the purity of subsequent products. The screened aronia berries are then sent to an ultrasonic cleaner. Running water is injected, and a 300-watt ultrasonic device is activated. Each cleaning session lasts 5 minutes, and the process is repeated 3 times. The cavitation effect of the ultrasonic waves removes dust, pesticide residues, and attached microorganisms from the surface of the fruit, ensuring the cleanliness of the raw materials. The cleaned fruit then enters a high-speed crusher, where it is crushed to a particle size of 5 to 10 mm. This particle size ensures the efficiency of subsequent processing without causing premature loss of pulp and juice due to over-crushing. The crushed material was degreased using Soxhlet extraction with hexane as the degreasing solvent. The material and solvent were mixed at a ratio of 1:8, and extracted at a constant temperature of 60°C for 2 hours. This process ensures that the fatty substances are fully dissolved by the hexane, preventing fat blockage of equipment pipelines or contamination of the active sites of the adsorption resin in subsequent processes. After degreasing, the material was transferred to a vacuum drying oven and dried at 55°C and a vacuum of -0.08 MPa for 8 hours until the moisture content dropped below 8%. The low-temperature vacuum environment reduces the loss of active ingredients in the raw material. Finally, the dried material was fed into an ultrafine pulverizer and pulverized. After sieving through an 80-100 mesh sieve, uniform aronia berry powder was obtained. The ultrafine pulverization significantly increased the specific surface area of ​​the powder, creating favorable conditions for sufficient contact between anthocyanins and the solvent in subsequent extraction stages. The sealed powder can be directly used in the next process.

[0024] Before extraction, an acidic extraction solvent was prepared by mixing ethanol and deionized water at a volume ratio of 6:4, and then adding a small amount of hydrochloric acid to adjust the pH of the solution to 2.5. The acidic environment can disrupt the binding structure of anthocyanins with polysaccharides in the raw material, promoting the dissolution of anthocyanins. The aronia berry powder and acidic extraction solvent were added to a sealed extraction tank at a solid-liquid ratio of 1:12. Nitrogen gas was then continuously introduced into the tank at a flow rate of 0.5 cubic meters per hour for 30 minutes to completely expel air and create an inert protective atmosphere. The inert nature of nitrogen effectively isolates oxygen, preventing the anthocyanins from being oxidized and degraded during subsequent extraction. After sealing the extraction tank, the built-in ultrasonic generator was activated, set to 500 watts of ultrasonic power and an extraction temperature of 45 degrees Celsius, and extraction was continued for 1.5 hours. During the extraction process, a slight positive pressure of 0.1 MPa was maintained inside the tank to further prevent air infiltration. The vibrational energy of ultrasound can disrupt the cell wall structure of ageberry, making it easier for anthocyanins within the cells to be released into the solvent. Compared to traditional thermal extraction methods, this ultrasound-assisted extraction can increase the anthocyanin extraction rate by 20% to 30%. Simultaneously, the low-temperature environment of 45 degrees Celsius, combined with inert protection, can control the oxidation loss of anthocyanins to within 5%. After extraction, the mixture is discharged through the discharge valve at the bottom of the extraction tank; this is the preliminary anthocyanin-containing extract, which is directly sent to the next processing stage.

[0025] In the staged filtration process, the extract first enters a plate and frame filter, where a stainless steel membrane with a pore size of 10 micrometers is installed. Under a filtration pressure of 0.3 MPa, solid impurities such as fruit pulp residue and fibers in the extract are trapped on the surface of the membrane. The collected coarse filtrate then enters the subsequent fine filtration step, which quickly removes large particulate impurities to prevent them from clogging the subsequent precision filtration equipment. The coarse filtrate is then passed through a ceramic membrane filter, using a ceramic membrane with a pore size of 0.22 micrometers. The filtration temperature is controlled at 30 degrees Celsius, and the cross-flow velocity is 2 meters per second. The precise pore size of the ceramic membrane effectively traps large molecular colloids, proteins, and some microorganisms in the coarse filtrate. If these impurities enter the subsequent processes, they may cause scaling in the concentration equipment or occupy the active sites of the adsorption resin. After two stages of filtration, the clarity of the collected permeate can reach over 95%, providing a clean feedstock for subsequent concentration and purification, reducing the maintenance costs of subsequent equipment, and improving the overall process efficiency.

[0026] In the low-temperature concentration stage, the clarified permeate is pumped into a vacuum rotary concentrator. The concentration temperature is set to 45 degrees Celsius and the vacuum level to -0.09 MPa. Simultaneously, the concentrator's reflux condenser is activated to recover the evaporated ethanol solvent. Under the low-temperature vacuum environment, water and ethanol in the permeate evaporate rapidly. Furthermore, the temperature of 45 degrees Celsius is far below the degradation temperature of anthocyanins, allowing the degradation rate of anthocyanins during concentration to be controlled below 3%. Concentration continues until the solid content of the permeate reaches 25%, at which point the operation is stopped. At this point, the concentration of anthocyanins in the crude concentrate is significantly increased, and the processing volume is reduced by approximately 75% compared to the original permeate. This change significantly reduces solvent consumption and processing time in subsequent chromatography steps, improving the overall economic efficiency of the process. After cooling to room temperature, the concentrated crude concentrate is sealed and stored to prevent contamination or loss of active ingredients due to prolonged exposure, preparing it for the core chromatography purification step.

[0027] S500, Magnetic Field Controlled Chromatographic Purification: A magnetic macroporous adsorption resin is prepared, and then the magnetic macroporous adsorption resin is packed between two supporting sieve plates in the chromatography column. A gradient magnetic field that increases along the flow direction of the feed liquid is generated by a magnetic field control device, driving the magnetic macroporous adsorption resin particles to locally fine-tune their positions and form a uniform fixed phase bed. The crude extract concentrate is then passed into the chromatography column at a gradient flow rate that decreases along the flow direction of the feed liquid to complete the anthocyanin adsorption. The preparation steps of the magnetic macroporous adsorption resin are as follows: S510, Matrix pretreatment: Take macroporous adsorption resin, soak it in 95% ethanol by volume to activate it, wash it with deionized water until neutral and vacuum dry it. S520, In-situ magnetic core loading: The pretreated macroporous adsorption resin is dispersed in deionized water to form a suspension, and a mixed solution of ferrous sulfate and ferric chloride is added. The total mass of the mixed solution is 15%-25% of the mass of the macroporous adsorption resin. The molar ratio of ferrous ions to ferric ions is 1:2. Ammonia water is added dropwise to adjust the pH to alkaline, and then the temperature is raised and kept warm to allow the ferric oxide magnetic cores to be deposited in-situ on the resin surface and in the pores. S530, Isolation layer coating: Add silane coupling agent to the suspension, and heat the reaction to form a silicon dioxide isolation layer on the surface of the magnetite core; the amount of silane coupling agent is 3%-8% of the mass of the macroporous adsorption resin, and is added after being diluted with ethanol in advance. S540, Post-treatment: Separate the resin, wash it with water until neutral and dry it to obtain magnetic macroporous adsorption resin.

[0028] Specifically, the preparation of the magnetic macroporous adsorption resin begins with step S510, matrix pretreatment. Industrially common D101 type macroporous adsorption resin is selected as the matrix material, as this type of resin possesses abundant pore structure and excellent adsorption performance. A measured amount of resin is placed in a sealed container, and 95% ethanol (by volume) is added, ensuring the resin is completely submerged. The soaking time is controlled at 24 hours, with manual stirring every 6 hours to ensure the ethanol fully penetrates into the resin pores, activating the resin. The activated resin pores will significantly expand, providing ample space for subsequent magnetic core loading. After soaking, the resin is transferred to a Buchner funnel and slowly rinsed with deionized water. The pH of the rinsing solution is checked every three rinses until it stabilizes at 7.0, meeting the neutral standard, to avoid residual ethanol affecting subsequent chemical reactions. The washed resin is placed in a vacuum drying oven at 60 degrees Celsius for 6 hours to thoroughly remove internal moisture. The dried resin has a loose texture, facilitating subsequent dispersion operations.

[0029] Proceed to step S520, the in-situ magnetic core loading step. First, disperse the pretreated macroporous adsorption resin in deionized water at a solid-liquid ratio of 1:10. Start the stirrer and stir at a speed of 300 revolutions per minute for 30 minutes to form a uniform and stable suspension.

[0030] Subsequently, a mixed solution of ferrous sulfate and ferric chloride was slowly added to the suspension. The total mass of the mixed solution was controlled to be 20% of the mass of the macroporous adsorption resin. This ratio ensures that the magnetic nucleus loading meets the magnetic field response requirements without excessively occupying the resin's adsorption sites. The molar ratio of ferrous ions to ferric ions in the mixed solution was strictly controlled at 1:2, which is crucial for generating pure magnetite (Fe3O4) magnetic nuclei. Next, 25% ammonia solution was slowly added dropwise to the suspension while stirring until the pH of the solution rose to 9.0, achieving an alkaline environment. Alkaline conditions provide the necessary reaction environment for the formation of magnetite. After the addition was completed, the heating device was activated, raising the temperature of the suspension to 65 degrees Celsius and maintaining this temperature for 2.5 hours. During this process, magnetite magnetic nuclei were deposited in situ on the resin surface and in the internal pores, giving the resin an initial magnetic field response capability.

[0031] In step S530, the isolation layer coating process requires the use of KH550 silane coupling agent. This type of coupling agent has strong bonding with inorganic materials and can effectively form a stable isolation layer. First, dilute the silane coupling agent with ethanol at a volume ratio of 1:5. The diluted coupling agent is easier to disperse evenly. The amount used should be controlled at 5% of the mass of the macroporous adsorption resin. This amount can form an isolation layer of suitable thickness on the surface of the magnetic core.

[0032] The diluted silane coupling agent was slowly added dropwise to the suspension with magnetic core loading, while stirring was maintained during the addition process. After the addition was completed, the temperature of the suspension was adjusted to 55 degrees Celsius, and the reaction was continued to be stirred for 5 hours.

[0033] During the reaction, the silane coupling agent undergoes a hydrolysis-condensation reaction on the surface of the magnetite core, gradually forming a dense silica isolation layer. This isolation layer can effectively protect the magnetite core from subsequent acid and alkali elution solutions, while not clogging the resin pores or affecting the resin's adsorption performance for anthocyanins.

[0034] In the S540 post-processing step, after turning off the stirrer, a strong magnet is attached to the outer wall of the container. The magnetic resin will quickly gather on the side wall of the container under the action of the magnetic field, and the upper clear liquid is poured out to achieve preliminary separation.

[0035] The collected resin was then transferred to a funnel and repeatedly rinsed with deionized water. The pH of the rinsing solution was checked every three rinses until it stabilized at 7.0, reaching neutrality. The washed resin was then placed back into a vacuum drying oven and dried at 60 degrees Celsius for 8 hours to completely remove internal moisture, ultimately yielding a magnetic macroporous adsorption resin.

[0036] These resins have an adsorption capacity of over 80 mg / g and also exhibit good magnetic field responsiveness, allowing them to flexibly adjust their position in a gradient magnetic field.

[0037] Meanwhile, in step S500, the gradient magnetic field is formed by two independent magnetic field generating units arranged along the axial direction of the chromatography column; the gradient flow rate is inversely matched with the magnetic field strength gradient to achieve full adsorption of anthocyanins of different molecular weights.

[0038] The gradient magnetic field is formed by two independent magnetic field generating units arranged along the axial direction of the chromatography column. Each unit uses an insulating ceramic frame with enameled copper wire wound around the outside as magnetic coils. The two coils are fixed to the outer wall of the chromatography column by stainless steel clamps. The upper coil is 50 mm from the top of the column and has 500 turns, while the lower coil is 50 mm from the bottom and has 1000 turns. A direct current of 0.8 amperes is applied to both coils, and the gradient magnetic field is constructed through the difference in the number of turns. The upper magnetic field strength is 0.1 Tesla, and the lower magnetic field strength is 0.3 Tesla, forming a magnetic field distribution that increases from top to bottom along the feed flow direction. Under the action of the gradient magnetic field, the magnetic resin experiences increasing magnetic force, driving the resin particles to locally fine-tune within the bed, ultimately forming a uniform and dense stationary phase bed, completely solving the channeling problem caused by uneven resin distribution in traditional chromatography.

[0039] The crude extract concentrate is pumped into the chromatography column via a dual-channel constant flow pump to achieve gradient flow rate control, creating an inverse fit with the magnetic field strength. The upper flow rate is set at 1.5 times the column volume per hour, while the lower flow rate is reduced to 0.8 times the column volume per hour. This flow rate design corresponds to the gradient magnetic field. When the feed solution passes rapidly through the upper section, small-molecule anthocyanins can quickly bind to the resin adsorption sites. The slower flow rate in the lower section provides sufficient diffusion and adsorption time for large-molecule anthocyanins, ensuring that anthocyanins of different molecular weights can fully interact with the resin. During chromatography, the temperature is stabilized at 30 degrees Celsius using a thermostatic jacket on the outside of the column. This temperature maintains the optimal adsorption activity of the resin while preventing the loss of anthocyanin activity.

[0040] S600, Gradient elution: The chromatography column is sequentially eluted with deionized water, low-concentration ethanol solution, and high-concentration ethanol solution, and the anthocyanin-enriched eluent is collected; wherein, the volume fraction of the low-concentration ethanol solution is 15%-25%, and the volume fraction of the high-concentration ethanol solution is 65%-75%; during the elution process, the elution flow rates of deionized water, low-concentration ethanol solution, and high-concentration ethanol solution decrease sequentially.

[0041] Specifically, before elution, the eluent needs to be prepared. The low-concentration ethanol solution is a 20% (v / v) aqueous ethanol solution, and the high-concentration ethanol solution is a 70% (v / v) aqueous ethanol solution. Both solutions and deionized water need to be filtered through a 0.22-micron filter membrane to remove tiny impurities and avoid contaminating the resin bed.

[0042] Then, the three eluents are passed into a constant temperature water bath and preheated to 30°C. The temperature is kept consistent with the chromatographic adsorption stage, which can maintain the stability of the resin pore size and ensure stable elution efficiency.

[0043] A UV detector was then connected to the outlet of the chromatography column, and the detection wavelength was set to 530 nm, which is the characteristic absorption wavelength of anthocyanins, enabling real-time monitoring of the anthocyanin concentration in the eluent.

[0044] After preparation, preheated deionized water is pumped into the chromatography column using a constant flow pump at a rate of 2 column volumes per hour. Deionized water has the strongest polarity and can form a stronger binding force with water-soluble impurities on the resin surface, thoroughly eluting sugars, inorganic salts, and residual small-molecule water-soluble impurities adsorbed on the resin. The eluent is continuously monitored during elution. When the UV detector reading stabilizes at the baseline (below 0.02 AU), it indicates that the water-soluble impurities have been completely eluted. This step consumes approximately 3 column volumes of deionized water and can remove more than 85% of the water-soluble impurities in the raw material, preventing them from co-enriching with anthocyanins in subsequent steps.

[0045] Then, switch to elution with a low-concentration ethanol solution, reducing the flow rate to 1.5 column volumes per hour. The 20% ethanol solution, with a polarity between deionized water and high-concentration ethanol, can specifically bind to weakly polar impurities on the resin, such as some flavonoids and low-molecular-weight phenols. The slow flow rate allows the ethanol solution sufficient time to penetrate the resin pores and fully interact with the weakly polar impurities for resolution. Elution continues until the UV detector reading returns to baseline. This step consumes 4 column volumes of low-concentration ethanol solution and removes over 90% of the weakly polar impurities. At this point, only anthocyanins and a small amount of strongly polar impurities remain on the resin, laying the foundation for high-purity enrichment.

[0046] Elution was then performed using a high-concentration ethanol solution, with the flow rate further reduced to 1 column volume per hour. The 70% ethanol solution has low polarity and a stronger binding affinity to anthocyanins than the resin, enabling efficient desorption of anthocyanins adsorbed on the resin. Slowing the flow rate ensures uniform distribution of the ethanol solution within the resin bed, allowing for thorough desorption of anthocyanins from each resin particle and preventing incomplete desorption due to excessively high flow rates. After elution began, the UV detector reading was closely monitored. Eluent collection commenced when the reading reached 0.1 AU and continued until the reading dropped back to 0.02 AU. This collected eluent is the anthocyanin-enriched eluent. This step consumes 5 column volumes of high-concentration ethanol solution, achieving an anthocyanin elution rate of over 95%. The purity of anthocyanins in the enriched eluent increased from approximately 60% after chromatography to around 80%.

[0047] S700, Refining process: The anthocyanin enrichment eluent is subjected to secondary concentration, two-phase extraction for impurity removal, drying and shaping, and stabilization treatment to obtain the finished anthocyanin product of *Ipomoea purpurea*.

[0048] Specifically, the anthocyanin enrichment eluent from step S600 is first transferred to a vacuum rotary concentrator. The concentration temperature is set to 45°C and the vacuum level to -0.09 MPa, and the reflux condenser is activated to recover ethanol. The low-temperature environment of 45°C prevents anthocyanin degradation due to high temperatures, while the vacuum condition accelerates the evaporation of ethanol and water. Simultaneously, the reflux condenser can increase the ethanol recovery rate to over 92%, reducing solvent consumption. Concentration continues until the solid content of the eluent reaches 50%, at which point the solution volume is reduced by approximately 60% compared to the original enrichment solution. This not only increases the anthocyanin concentration but also significantly reduces the throughput of subsequent extraction steps. After cooling to room temperature, the concentrated solution is transferred to a sealed container for later use to avoid contamination caused by prolonged exposure.

[0049] Ethyl acetate was then selected as the extraction solvent, as it clearly separates from the aqueous phase and efficiently dissolves non-polar impurities. The concentrate and ethyl acetate were added to a centrifugal extractor at a 1:1 volume ratio. The stirring speed was set to 500 rpm and continued for 30 minutes to ensure sufficient contact between the two liquids. Residual non-polar impurities in the concentrate were transferred to the ethyl acetate phase. After stirring, the stirrer was turned off, and the mixture was allowed to stand for 20 minutes to allow natural separation. The upper layer was the ethyl acetate phase containing impurities, and the lower layer was the aqueous phase rich in anthocyanins. The valve at the bottom of the extractor was opened, and the lower aqueous phase was slowly discharged, completing one extraction. To ensure thorough impurity removal, the extraction can be repeated twice. After two-phase extraction, the anthocyanin purity increased from 80% to over 90%, and the residual non-polar impurity content decreased to below 0.5%.

[0050] The extracted aqueous phase is then fed into a spray dryer, with the equipment parameters adjusted as follows: inlet air temperature 120℃, outlet air temperature 60℃, and atomization pressure 0.3MPa. Spray drying disperses the aqueous phase into tiny droplets through high-speed atomization, allowing for rapid contact with the high-temperature inlet air. The water in the droplets evaporates instantly, and the entire drying process takes only about 3 seconds, minimizing anthocyanin degradation caused by prolonged heating. The dried anthocyanins fall into a collector as powder, with a uniform purplish-red color and a moisture content controlled below 3%. This low moisture content effectively inhibits microbial growth and extends product shelf life. The collected dry powder is then sieved through an 80-mesh sieve to remove any agglomerated particles, ensuring uniform particle size.

[0051] Finally, ascorbic acid was added as a stabilizer to the dried anthocyanin powder at a concentration of 0.15% of the powder's mass. This effectively inhibits the oxidative degradation of anthocyanins. The powder and ascorbic acid were then fed into a double-helix mixer at a speed of 200 rpm for 15 minutes to ensure uniform distribution of the ascorbic acid within the anthocyanins. After mixing, the mixture was sealed under nitrogen protection, which further prevents contact between the anthocyanins and oxygen. The packaging used aluminum-plastic composite bags, which were vacuum-sealed, filled with nitrogen, sealed, and labeled. The stabilized anthocyanin product, when stored at room temperature for 12 months, showed an anthocyanin loss rate of less than 8%, significantly lower than the over 25% loss rate of products without stabilizers. The final anthocyanin product obtained had a purity of ≥90% and an activity retention rate of ≥85%, meeting the standards for food additives and health product raw materials. Comparative Example 2 Based on Example 1, this example uses the controlled variable method: the fixed variables are the raw material pretreatment, extraction, fractional filtration, low-temperature concentration, elution process framework and purification parameters; the only variable is the chromatography purification step, replacing the "magnetic field controlled magnetic macroporous adsorption resin chromatography" in Example 1 with the existing common process "ordinary macroporous adsorption resin static chromatography", and the other operating parameters (such as temperature, time, solvent ratio, etc.) are completely consistent with Example 1.

[0052] S500 chromatography purification (core differentiating step) The conventional "static chromatography with ordinary macroporous adsorption resin" in existing processes is used instead of the "magnetic resin chromatography controlled by magnetic field" in Example 1. The specific steps are as follows: Resin selection and pretreatment: Ordinary D101 macroporous adsorption resin (without magnetic core loading and isolation layer coating) with the same matrix as in Example 1 was selected. The pretreatment method was the same as in Example 1 (soaking in 95% ethanol for 24 hours → washing with water until neutral → vacuum drying at 60°C for 6 hours). The resin adsorption capacity was 55 mg / g (lower than ≥80 mg / g of magnetic resin).

[0053] Resin packing: 80g of ordinary D101 resin was packed into a chromatography column of the same specification (support sieve plate pore size 0.2mm), and the bed was formed by natural sedimentation. The bed height was 400mm. However, due to the lack of magnetic field control, the resin distribution was uneven, with local gaps and density differences. The bed uniformity was only 75%.

[0054] Adsorption operation: Without gradient magnetic field assistance, the crude extract concentrate was transported at a single flow rate of 1.2 BV / h (intermediate value of Example 1). The column temperature was controlled at 30℃ (consistent with Example 1). Feeding was stopped after 2.5 hours of adsorption. Due to uneven resin distribution and limited adsorption capacity, some of the feed solution did not fully contact the adsorption sites before effluent. The resin saturation adsorption capacity was 48 mg / g, the anthocyanin adsorption rate was only 72%, and the anthocyanin concentration in the effluent after adsorption reached 0.32 mg / mL (far higher than ≤0.05 mg / mL in Example 1).

[0055] S600 gradient elution (affected by chromatographic differences) The type, concentration, and detection method of the eluent were the same as in Example 1. However, due to uneven chromatographic adsorption and overlapping binding sites of impurities and anthocyanins, the elution effect decreased. The specific parameters and results were adjusted as follows: Deionized water elution: flow rate 2 BV / h, elution volume increased to 5 BV (3.5 BV in Example 1), time 2.5 h, water-soluble impurity removal rate was only 65% ​​(≥85% in Example 1), and the time for UV reading to stabilize to baseline was extended by 40%.

[0056] Low-concentration ethanol elution: 20% ethanol aqueous solution, flow rate 1.5 BV / h, elution volume increased to 6 BV (4 BV in Example 1), time 4h, weak polar impurity removal rate was only 70% (≥90% in Example 1), and some anthocyanins were lost with the impurities due to resin gaps, with a loss rate of 3.2% (≤0.5% in Example 1).

[0057] High-concentration ethanol elution: 70% ethanol aqueous solution, flow rate 1 BV / h, elution volume increased to 7 BV (5 BV in Example 1), time 7h. Because some anthocyanins were tightly wrapped by the resin and not fully adsorbed, the elution rate was only 78% (≥95% in Example 1). The purity of anthocyanins in the eluent after enrichment was only 58% (approximately 80% in Example 1).

[0058] S700 refining process (parameters are consistent, results are affected by previous steps). The operating parameters for secondary concentration, two-phase extraction, drying, and stabilization were exactly the same as in Example 1. However, due to poor elution effect in the preceding chromatography, the purified index was still lower than that in Example 1. The specific results are as follows: Secondary concentration: 3.2L of enriched eluent was concentrated to 1.2L with a solid content of 50% and an ethanol recovery rate of 92% (consistent with Example 1), but the anthocyanin concentration was only 185mg / mL (261mg / mL in Example 1).

[0059] Two-phase extraction: After two extractions with ethyl acetate, the removal rate of non-polar impurities was 95% (consistent with Example 1), but due to the low initial purity, the purity of anthocyanins after extraction was only 78% (Example 1 ≥ 90%).

[0060] Drying and stabilization: After spray drying, 205g of finished dry powder was obtained (313g in Example 1), with a moisture content of 2.9% (similar to Example 1). After stabilization with 0.15% ascorbic acid, it was stored at room temperature in a sealed container for 12 months, and the anthocyanin loss rate reached 15% (≤8% in Example 1).

[0061] In summary, by comparing Example 1 and Comparative Example 2, the following conclusions are drawn: 1. Magnetic modification and magnetic field regulation significantly improve resin adsorption performance: The magnetic macroporous adsorption resin used in Example 1, after being loaded with a magnetic core and coated with an isolation layer, achieved an adsorption capacity of over 80 mg / g, which is 66.7% higher than that of the comparative ordinary D101 resin (48 mg / g). The axial distribution of the gradient magnetic field (0.1 Tesla in the upper section and 0.3 Tesla in the lower section) drives the resin particles to fine-tune and form a uniform bed (uniformity 98%), completely solving the uneven distribution (uniformity 75%) and channeling problems caused by the natural sedimentation of the comparative resin. This increased the anthocyanin adsorption rate from 72% to 96%, and reduced the anthocyanin concentration in the effluent after adsorption from 0.32 mg / mL to ≤0.05 mg / mL, achieving sufficient contact between the feed liquid and the adsorption sites.

[0062] 2. Highly efficient adsorption lays the foundation for precise elution, doubling the efficiency of impurity removal and component enrichment: In Example 1, the uniform resin bed avoids the cross-entanglement of impurities and anthocyanin binding sites, increasing the removal rate of water-soluble impurities from 65% to 85% and the removal rate of weakly polar impurities from 70% to 90%; at the same time, it reduces anthocyanin encapsulation residue, the elution rate jumps from 78% to over 95%, the elution solvent consumption decreases from 18 BV to 12.5 BV, reducing solvent cost and elution time by 30.6%, and the purity of the eluent after enrichment also increases from 58% to 80%.

[0063] 3. Achieved breakthroughs in both product quality and yield: Benefiting from the efficient adsorption-elution process, the purity of the refined product in Example 1 reached over 90%, an increase of 15.4% compared to the comparative example (78%); based on 50kg of raw material, the yield of the finished product increased from 205g to 313g, an increase of 52.7%; after stabilization treatment, the anthocyanin loss rate after 12 months of storage at room temperature decreased from 15% to below 8%, and the antioxidant stability increased by 46.7%, fully meeting the standards for food additives and health product raw materials, while the purity of the finished product in the comparative example did not meet the requirements of this standard.

[0064] 4. Innovative process with significant industrial value: Example 1, through the synergistic design of "magnetic resin + gradient magnetic field", improves product quality and yield while reducing solvent consumption and equipment operation time. It solves industry pain points such as uneven distribution of traditional static chromatography resin, large material loss and difficulty in removing impurities. It takes into account both technological advancement and production economy, and provides a feasible solution for the high-purity industrial production of bromelain.

[0065] Example 3 like Figure 2-6 As shown, based on Example 1, this embodiment provides an anthocyanin purification device for implementing the steps of Example 1, including a magnetron chromatography device, and a raw material processing device, an ultrasonic extraction device, a grading filter device, a low-temperature concentration device, a gradient rinsing device, and a purification and collection device that are sequentially flanged and connected to the magnetron chromatography device via sealed feed pipelines; the shells of each device are made of corrosion-resistant metal, and sealing gaskets are provided at the interfaces between the sealed feed pipelines and each device; it also includes an integrated control box, which is electrically connected to the execution components of each device via cables; wherein, the magnetron chromatography device forms a sealed chamber for filling with magnetic macroporous adsorption resin.

[0066] Among them, such as Figure 2 As shown, the raw material processing device, ultrasonic lifting device, grading and filtering device, low temperature concentration device, gradient washing device and refining and collecting device are all existing equipment.

[0067] Specifically, the raw material processing unit consists of a vibrating screen, a washing machine, a crusher, a degreasing device, a vacuum drying oven, and an ultrafine pulverizer, all sealed and connected in sequence according to the material flow direction. The various pieces of equipment are connected via pipelines with conveying augers. The vibrating screen first selects clean, uniformly sized arugula berries. After the berries are cleaned by a high-pressure spray washing machine to remove surface dirt and impurities, they are fed into the crusher to be processed into granules suitable for subsequent processing. The granules then enter the degreasing device, where they come into full contact with food-grade organic solvents to remove lipids and reduce interference in subsequent extraction. The degreased granules are then sent to the vacuum drying oven for dehydration to a low moisture content under gentle conditions. Finally, the ultrafine pulverizer produces a fine fruit powder. The entire pretreatment process ensures the purity of the raw materials and the efficiency of anthocyanin dissolution. The discharge end of this unit is connected to the inlet flange of the ultrasonic lifting device via a sealed pipeline equipped with a variable frequency pump. The variable frequency pump can dynamically adjust the feeding speed according to the amount of fruit powder being conveyed.

[0068] The ultrasonic extraction device is a sealed extraction tank equipped with an ultrasonic generator, a stirrer, and a nitrogen inlet. Its inlet receives fruit powder from the raw material processing unit, and the tank contains a pre-mixed acidic ethanol solvent. After the fruit powder and solvent are mixed at an optimized solid-liquid ratio, the stirrer continuously agitates at a suitable speed, while nitrogen is simultaneously introduced into the tank through the nitrogen inlet to completely eliminate air and create an inert protective atmosphere to prevent anthocyanin oxidation. Subsequently, the ultrasonic generator is activated, producing ultrasonic vibrations of a specific frequency, which are transmitted to the extraction liquid through a transducer. This vibration is maintained at a constant temperature for a certain period, promoting the efficient dissolution of anthocyanins into the solvent. The outlet of the device is connected to the inlet of a grading filter device via a pipeline equipped with a pressure sensor. The pressure sensor provides real-time feedback on the pipeline pressure to prevent subsequent filter blockage and abnormal pressure.

[0069] The graded filtration system comprises two stages: a plate and frame filter and a ceramic membrane filtration system, arranged in series. The plate and frame filter first removes large particles of fruit pulp and powder from the extract under stable filtration pressure. The filtrate then enters the ceramic membrane filtration system, where a ceramic membrane with a specific pore size traps large molecular impurities such as proteins and pectin, ultimately yielding a highly clear anthocyanin extract. The clarified liquid outlet of this system connects to the inlet flange of the low-temperature concentration unit via a sanitary quick-connect coupling, ensuring no secondary contamination during filtrate transport.

[0070] The main body of the low-temperature concentration unit is a vacuum rotary evaporator. Its feed end receives the clarified extract from the staged filter device, and the extract is concentrated under vacuum and gentle heating conditions. During the process, most of the ethanol solvent is evaporated, liquefied by a condensation recovery device, and then sent to the eluent preparation tank for recycling. The volume of the extract is significantly reduced, and the anthocyanin concentration is significantly increased. The concentrated high-concentration solution is sent to the magnetron chromatography unit through an insulated delivery pipe to prepare for the core purification stage. This delivery pipe is equipped with a flow regulating valve, and the feed rate is automatically adjusted by the integrated control box according to the liquid level in the chromatography column 1.

[0071] like Figure 3-5 As shown, the magnetron chromatography apparatus is the core of the equipment. Its main chromatography column 1 is a hollow cylinder with standard flanges at both ends. The inner diameter is adapted to the throughput, and the wall thickness meets the pressure requirements. The inner wall is mirror-polished to reduce resin adhesion. The connection interfaces of the column are precisely laid out according to function: a feed port is opened on the top side wall, the diameter of which matches the insulated delivery pipe of the low-temperature concentration unit. The delivery pipe is connected to the flange. The eluent inlet is opened at the top of the chromatography column 1, which corresponds to the output pipe of the gradient elution unit. The mixed liquid outlet of the gradient elution unit and the eluent return pipe are connected by flanges through electromagnetic three-way valves to form an eluent circulation path. like Figure 4 As shown, a discharge pipe 8 is provided at the bottom of the chromatography column 1. The discharge pipe 8 is connected to the purification and collection device and the resin recovery pipe through a three-way valve. By manually adjusting the three-way valve, the resin can be allowed to flow to the outside for recovery, while the anthocyanin enrichment eluent can be allowed to enter the purification and collection device.

[0072] like Figure 4-6 As shown, the inside of the column is arranged from top to bottom as follows: upper sieve plate assembly 2, magnetic macroporous adsorption resin filling area, and lower sieve plate assembly 3.

[0073] The upper screen plate assembly 2 includes an upper screen plate body 20 and an upper support ring 10. The upper support ring 10 is welded and fixed to the inner wall of the column. Multiple evenly distributed plug-in rods 12 are protruding on it. The upper screen plate body 20 has corresponding plug holes on its edge and is fixed to the upper support ring 10 by plugging and connecting. It adopts a detachable design for easy maintenance. The upper screen plate body 20 is a 316L stainless steel perforated plate with a pore size that matches the resin particle size (slightly smaller than the minimum resin particle size), which both prevents the resin from floating and ensures the smooth passage of the liquid.

[0074] The lower sieve plate assembly 3 is a key structure for resin retention and recycling, including a fixed sieve plate 30, a movable sieve plate 31, a lifting support rod 32, and a lower support ring 11.

[0075] The lower support ring 11 is welded to the middle of the inner wall of the column and is fixedly connected to the center of the fixed screen plate 30 through multiple anti-corrosion connecting rods 13, so that the fixed screen plate 30 is horizontally suspended. A suitable leakage gap 33 is reserved between its edge and the inner wall of the column, which is a dedicated channel for resin recovery.

[0076] The movable screen plate 31 is slidably disposed below the fixed screen plate 30, and its edge is rigidly connected to the top of the lifting support rod 32. The lifting support rod 32 extends to the outside through the sealing sleeve at the bottom of the column, and its lower end is connected to the piston rod flange of the drive cylinder 34. The drive cylinder 34 is fixed to the load-bearing base at the bottom of the column by a bracket, which can drive the movable screen plate 31 to rise and fall. During adsorption and elution, the movable screen plate 31 rises and fits tightly with the fixed screen plate 30 to form a complete support plane, which, together with the upper screen plate, forms a sealed resin filling chamber. During resin recovery, the movable screen plate 31 descends and opens the leakage gap 33.

[0077] The chromatography column 1 is equipped with a gradient magnetocontrol assembly 4 and a temperature control assembly 5, and the lower end is connected to the discharge hopper 6 and the gas-assisted discharge assembly. The gradient magnetocontrol assembly 4 includes two sets of magnetic coil units distributed along its axial direction, which are sleeved on the outside of the chromatography column 1. They are formed by winding enameled coils 41 of suitable specifications on an insulating frame 40. From the feed end to the discharge end, the number of coil turns increases sequentially. The input current is adjusted by an integrated control box to form a gradient magnetic field inside the column, which guides the resin to form a density gradient distribution and improves the separation accuracy. Each unit is covered with a magnetic shield 42 to prevent the magnetic field from leaking out.

[0078] The temperature control component 5 includes a spiral heat exchange tube 50 that is closely attached to the inner wall of the column and a temperature probe 51 inserted into the resin layer. The inlet of the heat exchange tube 50 is at the top of the column and the outlet is at the bottom. The circulating fluid is delivered through an external constant temperature device to achieve precise temperature control inside the column. The temperature probe 51 provides real-time temperature feedback to the integrated control box to form a closed-loop temperature control.

[0079] The discharge hopper 6 has a conical structure. The large-diameter end is sealed to the flange at the bottom of the column, and the small-diameter end is connected to the discharge pipe 8 with a pneumatic valve 7. The discharge pipe 8 is divided into two paths through a three-way valve: one path is connected to the flange of the refining and receiving device through an insulated pipeline, and the other path is connected to the resin recovery pipeline through a butterfly valve.

[0080] The air-assisted discharge assembly includes an airflow pipe 9, which is inserted obliquely into the side wall of the discharge hopper 6 and connected to the column. It is externally connected to a high-pressure nitrogen source through an air pipe. An electromagnetic shut-off valve and a flow regulating valve are connected in series on the air pipe. The electromagnetic shut-off valve is electrically connected to the integrated control box and is linked with the drive cylinder 34 for control.

[0081] The gradient elution apparatus, as a mature existing device, consists of multiple eluent storage tanks, gradient pumps, static mixers, and electromagnetic three-way valves. These components are connected in series via sanitary piping. The storage tanks are configured according to the eluent concentration gradient (one each for low, medium, and high concentrations). Each tank is equipped with a stirrer and a level gauge. The stirrer ensures uniform solvent concentration, and the level gauge provides real-time level feedback and is linked to the integrated control box, automatically triggering a replenishment reminder when the level is low. The gradient pumps are high-precision plunger pumps, allowing for precise adjustment of the discharge flow rate from different storage tanks, with a flow rate error controlled within ±1%. The static mixer has built-in spiral blades for rapidly and uniformly mixing eluents of different concentrations, and its outlet is connected to the eluent inlet of chromatography column 1 via piping.

[0082] The refining and receiving device is also a standard food-grade equipment. The main body is a jacketed 316L stainless steel storage tank (volume matched to the equipment's processing capacity). The tank structure and connection design combine functionality and safety: a low-speed agitator is installed at the center of the tank top, with an anchor-type agitator blade that stays close to the tank wall without touching the sensor probe, preventing anthocyanin solution precipitation and stratification; a CIP cleaning ball interface is located on one side of the tank top, connecting to the factory's CIP cleaning system, and a breather valve and sampling port are located on the other side. The breather valve has a built-in sterile filter membrane to prevent external contamination and balance the pressure inside the tank; the sampling port is equipped with a sanitary diaphragm valve, facilitating real-time sample extraction for purity testing; a capacitive level sensor (range 0 - tank volume) is vertically installed inside the tank. The online density meter's sensor probe extends halfway into the tank, collecting real-time liquid level and density signals which are transmitted to the integrated control box via shielded cables. When any parameter reaches a preset value, a linkage control is immediately triggered. The tank wall jacket is divided into upper and lower sections, connecting to the constant-temperature hot water and cooling water circuits respectively. The integrated control box adjusts the medium flow rate to achieve precise temperature control within the tank. The tank bottom features a conical structure with a discharge port at the lowest point, where a Y-type filter, a sanitary pneumatic diaphragm valve, and a quick-connect fitting are sequentially installed. This prevents impurities from entering the finished product and facilitates quick connection to filling equipment. A drain outlet is located next to the discharge port for discharging waste liquid after cleaning. A liquid level observation mirror is installed on the outside of the tank for operators to visually monitor the equipment status.

[0083] The complete working process of the equipment is as follows: First, various process parameters are preset through the integrated control box, including ultrasonic power, chromatography temperature, gradient magnetic field current value, eluent concentration gradient, etc., and then the equipment is started.

[0084] Operators feed the aronia berry raw materials into the raw material processing device. After being screened by a vibrating screen, the raw materials are processed into qualified granules by a washing machine and a crusher. The granules enter the degreasing device to remove lipids, and then are dehydrated by a vacuum drying oven. The granules are then ground into fine fruit powder by an ultra-fine pulverizer. The fruit powder is then fed into the ultrasonic lifting device by a frequency converter at a preset flow rate.

[0085] Inside the ultrasonic extraction device, fruit powder and acidic ethanol solvent are mixed in a specific ratio. The stirrer is activated, and nitrogen is introduced to purge air. After the ultrasonic generator is activated, the mixture is continuously subjected to constant temperature for a certain period, allowing anthocyanins to fully dissolve into the extract. After extraction, the mixture enters a graded filtration device via a pipeline monitored by a pressure sensor. First, a plate and frame filter removes large particles, then a ceramic membrane filtration system retains large molecular impurities, yielding a clear extract. The clear extract then enters a low-temperature concentration device, where it is concentrated to a suitable volume in a vacuum rotary evaporator. The ethanol recovered during concentration is sent to an eluent preparation tank for reuse. The high-concentration solution is then transported to a magnetron chromatography unit via an insulated pipe.

[0086] After passing through the feed inlet at the top of the chromatography column 1, the feed solution permeates through the upper sieve plate and enters the resin-filled zone. At this time, the integrated control box activates the gradient magnetic control component 4, and a preset current is applied to each magnetic coil unit to form a gradient magnetic field. Under the action of the magnetic field, the magnetic macroporous adsorption resin is gradient-distributed, selectively adsorbing anthocyanins in the feed solution, while water-soluble impurities pass through the resin layer and are discharged through the temporary drain valve at the bottom of the column. After adsorption is complete, the temporary drain valve is closed, and the gradient elution device is activated. The integrated control box regulates the gradient pumps of each storage tank according to a preset program. Low-concentration ethanol eluent, after being mixed by a static mixer, is injected into the eluent inlet of the column through an electromagnetic three-way valve, flowing evenly down the column wall to remove weakly polar impurities from the resin surface. The impurity eluent enters the waste storage tank of the low-temperature concentration unit through the purified liquid outlet. Subsequently, the gradient pumps gradually adjust the flow rate ratio of each storage tank to steadily increase the eluent concentration. Simultaneously, the integrated control box adjusts the magnetic coil current to change the magnetic field strength, promoting efficient desorption of anthocyanins. The high-purity eluent enters the stainless steel storage tank of the refining and receiving unit through the shut-off valve at the purified liquid outlet. A low-speed stirrer inside the tank starts synchronously, and the anchor-type impeller rotates slowly to prevent product sedimentation. A constant-temperature medium is circulated through the jacket to maintain a stable temperature inside the tank. Operators can periodically extract samples through the sampling port on the top of the tank to test the purity and concentration of anthocyanins; the data serves as a basis for adjusting process parameters.

[0087] When the capacitive level sensor of the refining and receiving device detects that the finished product has reached the preset storage capacity, or when the online density meter reports that the concentration meets the standard, it immediately sends a signal to the integrated control box, and the equipment automatically performs the linkage operation: first, it closes the gradient pump and electromagnetic three-way valve of the gradient rinsing device, shuts down the temperature control system and gradient magnetic control component 4 of the magnetron chromatography device, and then the agitator of the refining and receiving device switches to low-speed pressure holding operation, and the jacket continuously introduces a constant temperature medium.

[0088] If the finished product needs to be transferred, the operator can open the pneumatic diaphragm valve at the bottom of the tank through the integrated control box. After being filtered by the Y-type filter, the finished product is connected to the filling equipment through a quick-connect connector. If the product is not to be transferred immediately, the CIP cleaning system can be started to clean the feed pipeline online to prevent residual liquid from deteriorating. After the finished product is processed, the equipment starts the resin recovery program: the integrated control box controls the drive cylinder 34 to drive the lifting support rod 32 downward, the movable screen plate 31 separates from the fixed screen plate 30, and the leakage gap 33 opens; at the same time, the electromagnetic shut-off valve of the air-assisted discharge component is opened, and high-pressure nitrogen is injected into the discharge hopper 6 through the nozzle. Under the propulsion of the airflow and the action of gravity, the resin enters the recovery pipeline through the resin recovery port at the bottom of the column for recovery.

[0089] After cleaning, rinsing, drying, and regeneration, the resin can be fed back into chromatography column 1 through the feed inlet at the top of the column for reuse, achieving resource recycling. Throughout the process, the integrated control box records process information such as the pressure at each port of chromatography column 1, and the temperature and concentration of the purification and collection device in real time. If pipeline blockage (abnormal pressure) or temperature exceeding the limit occurs, an audible and visual alarm is immediately triggered, and the feed valves of the relevant equipment are automatically shut off to ensure safe operation.

[0090] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0091] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A purification process for anthocyanins from *Alopecurus aureus*, characterized in that, Includes the following steps: S100. Raw material pretreatment and crushing: The aronia berry raw material is sequentially screened, washed, crushed, degreased, dried and crushed to obtain aronia berry powder. S200 Extraction: The aronia berry powder is mixed with an acidic extraction solvent, and an inert gas is introduced to form a protective atmosphere before ultrasonic-assisted extraction is performed to obtain an extract. S300, graded filtration: The extract is subjected to coarse filtration and fine filtration in sequence to remove solid impurities and macromolecular colloids, and the permeate is collected; S400, Low-temperature concentration: The permeate is concentrated at low temperature to obtain a crude concentrate; S500, Magnetic Field Controlled Chromatographic Purification: A magnetic macroporous adsorption resin is prepared, and then the magnetic macroporous adsorption resin is packed between two supporting sieve plates in the chromatography column. A gradient magnetic field that increases along the flow direction of the feed liquid is generated by a magnetic field control device, driving the magnetic macroporous adsorption resin particles to locally fine-tune their positions and form a uniform fixed phase bed. The crude extract concentrate is then passed into the chromatography column at a gradient flow rate that decreases along the flow direction of the feed liquid to complete the anthocyanin adsorption. S600, gradient elution: The chromatography column is sequentially eluted with deionized water, low-concentration ethanol solution and high-concentration ethanol solution, and the anthocyanin enriched eluent is collected. S700, Refining process: The anthocyanin enrichment eluent is subjected to secondary concentration, two-phase extraction for impurity removal, drying and shaping, and stabilization treatment to obtain the finished anthocyanin product of *Ipomoea purpurea*.

2. The purification process for anthocyanins from *Aristolochic acid* according to claim 1, characterized in that, In step S500, the preparation steps of the magnetic macroporous adsorption resin are as follows: S510, Matrix pretreatment: Take macroporous adsorption resin, soak it in 95% ethanol by volume to activate it, wash it with deionized water until neutral and vacuum dry it. S520, In-situ loading of magnetic nuclei: The pretreated macroporous adsorption resin is dispersed in deionized water to form a suspension. A mixed solution of ferrous sulfate and ferric chloride is added, wherein the molar ratio of ferrous ions to ferric ions is 1:

2. Ammonia water is added dropwise to adjust the pH to alkaline, and then the temperature is raised and kept warm, so that the magnetite magnetic nuclei are deposited in-situ on the resin surface and in the pores. S530, Isolation layer coating: Add silane coupling agent to the suspension and heat the reaction to form a silicon dioxide isolation layer on the surface of the magnetite core; S540, Post-treatment: Separate the resin, wash it with water until neutral and dry it to obtain magnetic macroporous adsorption resin.

3. The purification process for anthocyanins from *Aristolochic acid* according to claim 2, characterized in that, In step S520, the total mass of the mixed solution is 15%-25% of the mass of the macroporous adsorption resin; in step S530, the amount of the silane coupling agent is 3%-8% of the mass of the macroporous adsorption resin, and it is added after being diluted with ethanol beforehand.

4. The purification process for anthocyanins from *Aristolochic acid* according to claim 1, characterized in that, In step S500, the gradient magnetic field is formed by two independent magnetic field generating units arranged along the axial direction of the chromatography column; the gradient flow rate is inversely matched with the magnetic field strength gradient to achieve full adsorption of anthocyanins of different molecular weights.

5. The purification process for anthocyanins from *Aristolochic acid* according to claim 1, characterized in that, In step S600, the volume fraction of the low-concentration ethanol solution is 15%-25%, and the volume fraction of the high-concentration ethanol solution is 65%-75%; during the elution process, the elution flow rates of deionized water, low-concentration ethanol solution, and high-concentration ethanol solution decrease sequentially.

6. A purification device for anthocyanins from *Aristolochic acid*, used to implement the purification process described in any one of claims 1-5, characterized in that, The system includes a magnetron chromatography apparatus, and a raw material processing device, an ultrasonic lifting device, a grading and filtration device, a low-temperature concentration device, a gradient rinsing device, and a refining and collecting device, which are sequentially flanged and connected to the magnetron chromatography apparatus via sealed feed pipelines. The housings of each device are made of corrosion-resistant metal, and sealing gaskets are provided at the interfaces between the sealed feed pipelines and each device. The system also includes an integrated control box, which is electrically connected to the actuators of each device via cables. The magnetron chromatography apparatus has a sealed chamber inside for filling with magnetic macroporous adsorption resin.

7. The aralia elata anthocyanin purification device according to claim 6, characterized in that, The magnetron chromatography apparatus includes a chromatography column (1), an upper sieve plate assembly (2), and a lower sieve plate assembly (3). The chromatography column (1) is a hollow cylinder with flanges at both ends. The upper sieve plate assembly (2) includes an upper sieve plate body (20), which is a porous plate structure, fixedly connected to the inner wall of the chromatography column (1), and detachably installed. The lower sieve plate assembly (3) includes a fixed sieve plate (30), a movable sieve plate (31), and a lifting support rod (32). The fixed sieve plate (30) is located in the middle of the chromatography column (1), forming a leakage gap (33) between it and the inner wall of the chromatography column (1). The movable sieve plate (31) is slidably installed inside the chromatography column (1) and connected to the lifting support rod (32). The movable sieve plate (31) and the fixed sieve plate (30) can be combined to close the leakage gap (33).

8. The aralia elata anthocyanin purification device according to claim 7, characterized in that, The magnetron chromatography apparatus further includes a gradient magnetron assembly (4), which includes at least two magnetic coil units. Each magnetic coil unit includes an insulating frame (40), an enameled coil (41), and a terminal block. The insulating frame (40) is a cylindrical structure fitted onto the outer wall of the chromatography column (1). The enameled coil (41) is wound around the outside of the insulating frame (40). The terminal block is fixed at the end of the insulating frame (40) and electrically connected to the enameled coil (41). Along the axial direction of the chromatography column (1) from the feed end to the discharge end, the number of turns of the enameled coil (41) of each magnetic coil unit increases sequentially, and each magnetic coil unit is covered with a magnetic shield (42).

9. The argan oil anthocyanin purification device according to claim 7, characterized in that, The magnetron chromatography device also includes a temperature control component (5) and a discharge hopper (6); the temperature control component (5) includes a spiral heat exchange tube (50) fixed inside the chromatography column (1), with its inlet and outlet located at the lower and upper sides respectively; it also includes a temperature probe (51) installed inside the chromatography column (1); the discharge hopper (6) is a conical structure, with its large-diameter end sealed to the bottom flange of the chromatography column (1), and its small-diameter end equipped with a discharge pipe (8) with a pneumatic valve (7), which is connected to the sealed conveying pipeline flange of the refining and receiving device.

10. The aralia elata anthocyanin purification device according to claim 8, characterized in that, The magnetron chromatography device also includes a gas-assisted discharge assembly, which includes an airflow pipe (9) and a control valve group. One end of the airflow pipe (9) is obliquely connected to the side wall of the discharge hopper (6) and communicates with the inside of the discharge hopper (6), while the other end is connected to a high-pressure gas source through a quick-connect connector. The control valve group includes an electromagnetic shut-off valve and a flow regulating valve, which are connected in series on the airflow pipe (9), and the electromagnetic shut-off valve is electrically connected to the integrated control box through a cable. The lower end of the lifting support rod (32) is connected to a drive cylinder (34), and the drive cylinder (34) and the electromagnetic shut-off valve are linked and controlled through the integrated control box.

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