Cassia seed extraction process

Abstract

The invention relates to the technical field of extraction of traditional Chinese medicinal materials, and discloses a semen cassiae extraction process which comprises the following six steps: bubble blasting pretreatment, selective chelation, liquid drop atomization treatment, circulating microwave heating, phase state conversion separation and chelating agent recycling. Through the synergistic effect of multiple technologies, the technical problems that the anthraquinone compounds in the semen cassiae are low in extraction efficiency, activity is easy to degrade, and a chelating agent is difficult to recycle are solved, low-temperature efficient extraction, chelating agent recycling and all-component balanced extraction are achieved, the extraction efficiency is improved by 40% or above, the solvent dosage is reduced by 50% or above, and the method is suitable for industrial production. And the recovery rate of the chelating agent reaches 85% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of traditional Chinese medicine extraction, and more particularly to a cassia seed extraction process. Background Art

[0002] As a traditional Chinese medicinal material, Cassia seed contains rich anthraquinone compounds, which have the effects of clearing heat and improving eyesight, moistening the intestines and promoting bowel movements, and are widely used in the fields of medicine and health food. In the existing technology, the extraction methods of Cassia seed anthraquinone compounds mainly include hot water extraction and organic solvent extraction. Although the hot water extraction method is safe and environmentally friendly, the extraction efficiency is low and the content of the target component is low due to the large difference in polarity of anthraquinone compounds and the low polarity and insolubility of free anthraquinone in water. Although the organic solvent extraction method can improve the extraction efficiency, it has problems such as large solvent consumption and serious environmental pollution. In recent years, bubble explosion technology and microwave-assisted extraction technology have been applied in the field of plant active ingredient extraction, but a single technology still has limitations.

[0003] Currently, the extraction process for Cassia seed suffers from the following technical challenges: First, traditional extraction methods are inefficient, time-consuming, and require large amounts of solvent. Second, high temperatures during the extraction process can easily reduce the activity and damage the structure of heat-sensitive anthraquinone compounds. Third, uneven extraction of anthraquinone components of varying polarity can lead to partial loss of active ingredients. Fourth, auxiliary reagents such as chelating agents are expensive and environmentally taxing to use once. Fifth, anthraquinone compounds are susceptible to oxidative degradation during the extraction process. Therefore, a new, efficient, low-temperature, and environmentally friendly process for extracting anthraquinone compounds from Cassia seed is needed. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a Cassia seed extraction process, comprising a raw material pretreatment step, and the extraction process further comprising the following steps:

[0005] Step 1: Bubble explosion pretreatment: The pretreated Cassia seed powder is mixed with a 70% ethanol aqueous solution at a solid-liquid ratio of 1:5-1:8, and 0.8-1.2 MPa high-pressure nitrogen is introduced for 15-25 minutes to allow the nitrogen to penetrate into the Cassia seed powder particles in the form of microbubbles. The pressure is then quickly reduced to 0.1-0.15 MPa to generate a pressure gradient to cause bubble explosion. This cycle is repeated 3-5 times.

[0006] Step 2: Selective chelation: Add natural ligand as chelating agent to the mixture after bubble explosion pretreatment, and react at 35-40℃ and pH 5.5-6.5 for 40-60 minutes;

[0007] Step 3: Droplet atomization treatment: The chelated mixture is atomized into micron-sized droplets of 15-30 μm under nitrogen protection and circulated for 30-45 minutes;

[0008] Step 4: cyclic microwave heating: the atomized mixture is subjected to intermittent microwave heating at a temperature of 50-55°C for 20-30 minutes;

[0009] Step 5: Phase transition separation: adding a phase transition trigger to the microwave-heated extract, adjusting the pH to 4.0-4.5 to form a two-phase system, and separating to obtain an anthraquinone compound-rich extract and a chelating agent-rich recovery phase;

[0010] Step 6: Chelating agent recovery cycle: The recovered phase is treated to recover the chelating agent and used for the next batch of extraction.

[0011] Preferably, the bubble explosion pretreatment is performed under a nitrogen protective environment to provide an inert protective environment to prevent oxidation of anthraquinone compounds.

[0012] Preferably, the natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 40-55 parts of citric acid, 25-40 parts of β-cyclodextrin, 10-20 parts of glycyrrhizic acid and 5-10 parts of green tea polyphenols; the added amount of the chelating agent is 1.5-3% of the dry weight of Cassia seed.

[0013] Preferably, the natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 40 parts of citric acid, 25 parts of β-cyclodextrin, 20 parts of glycyrrhizic acid and 10 parts of green tea polyphenols; the added amount of the chelating agent is 3% of the dry weight of Cassia seed.

[0014] Preferably, the natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 55 parts of citric acid, 40 parts of β-cyclodextrin, 10 parts of glycyrrhizic acid and 5 parts of green tea polyphenols; the added amount of the chelating agent is 1.5% of the dry weight of Cassia seed.

[0015] Preferably, the natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 48 parts of citric acid, 32 parts of β-cyclodextrin, 15 parts of glycyrrhizic acid and 8 parts of green tea polyphenols; the added amount of the chelating agent is 2.2% of the dry weight of Cassia seed.

[0016] Preferably, the operating parameters of the droplet atomization treatment include: atomization pressure 0.5-0.8 MPa, atomization nozzle aperture 50-80 μm, atomization angle 60-90°, circulation flow rate 40-60 L / h, and the temperature of the entire system maintained at 40-45°C.

[0017] Preferably, the microwave frequency of the cyclic microwave heating is 2450±50 MHz, the microwave power is 300-500 W, a pulse mode with a ratio of working time to stopping time of 2:1 is adopted, and the circulation flow rate is 30-50 L / h.

[0018] Preferably, the phase transition trigger is a sodium acetate solution with a concentration of 30-40%, and the added amount is 15-25% of the volume of the extract.

[0019] Preferably, the chelating agent recovery cycle includes the following treatment steps: adjusting the pH value to 7.0-7.5, adding 5-8% of the volume of the recovery phase activated carbon to adsorb impurities, stirring at 60°C for 15-20 minutes, filtering to remove the activated carbon and impurities, and concentrating the treated chelating agent solution to 1.2-1.5 times the original concentration.

[0020] The extraction process achieves low-temperature and efficient extraction of anthraquinone compounds from Cassia seed, increasing the extraction rate of total anthraquinone compounds by 40-45%, and shortening the extraction time from 4-6 hours in the traditional process to 2-3 hours.

[0021] The extraction process achieved a chelating agent recovery rate of over 85% through phase conversion separation and chelating agent recovery cycle, and the activity remained above 90% of the initial level after being reused five times.

[0022] The extraction process increases the gas-liquid contact area by about 500-800 times through the synergistic effect of droplet atomization and bubble explosion pretreatment, improves mass transfer efficiency, and reduces solvent usage by 50-55%.

[0023] The beneficial effects of the present invention are:

[0024] Compared with traditional extraction methods, this process has significantly improved extraction efficiency: 1) the extraction rate of total anthraquinone compounds increased by 40-45%, and the extraction time was shortened from 4-6 hours in the traditional process to 2-3 hours; 2) the extraction yields of major anthraquinone compounds such as emodin, chrysophanol, and chrysophanol increased by 42%, 38%, and 46%, respectively; 3) the total anthraquinone content in the extract reached 4.2-4.6%, while the traditional process was only 2.8-3.2%.

[0025] This effect is mainly attributed to the synergistic effects of efficient wall breaking by bubble explosion, interface expansion by droplet atomization, and uniform heat transfer by microwave heating, which form an efficient three-dimensional extraction network.

[0026] This process achieves efficient extraction at lower temperatures: 1) The extraction temperature is reduced from 70-80°C in the traditional process to 50-55°C, reducing the degradation of heat-sensitive anthraquinone compounds; 2) The biological activity retention rate of anthraquinone compounds in the extract reaches over 95%, while the traditional high-temperature extraction process is usually 75-85%; 3) In particular, for aloe-emodin, which is highly heat-sensitive, the activity retention rate is increased from 70% in the traditional process to 92%.

[0027] This effect is mainly attributed to the need for selective chelation to reduce the extraction temperature and the uniform heat transfer characteristics of cyclic microwave heating, which avoids damage to the active ingredients due to local overheating.

[0028] This process significantly reduces solvent usage: 1) Compared with traditional solvent extraction, the solvent usage of this process is reduced by 50-55%; 2) The solid-liquid ratio is reduced from the traditional 1:12-15 to 1:5-8, greatly reducing solvent consumption; 3) Phase conversion separation replaces traditional multiple solvent extractions, further reducing the use of organic solvents.

[0029] This effect is mainly attributed to the synergistic effects of droplet atomization to increase the interfacial area, bubble explosion to enhance the wall breaking effect, and selective chelation to increase the dissolution rate, which enables anthraquinone compounds to be efficiently dissolved under less solvent conditions.

[0030] This process achieves efficient recycling of chelating agents: 1) The chelating agent recovery rate reaches over 85%, significantly reducing costs; 2) After five cycles of use, the chelating agent activity still remains above 90% of the initial level; 3) Compared with traditional disposable auxiliary reagents, the chelating agent cost of this process is reduced by 70-80%.

[0031] This effect is mainly attributed to the innovative application of phase conversion separation and chelating agent recovery and circulation technology, which forms a complete closed-loop process and embodies the concepts of green chemistry and circular economy.

[0032] This process achieves balanced extraction of anthraquinone compounds of different polarity: 1) The difference in extraction rate of high-, medium-, and low-polarity anthraquinone components is narrowed to less than 15%, while traditional processes usually range from 30-40%; 2) The extraction rate of low-polarity anthraquinone compounds is increased by 50-60%; 3) The ratio of various anthraquinone components in the extract is closer to the natural distribution in Cassia seed, maintaining its overall efficacy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The relationship between different extraction temperatures and aloe-emodin retention rate of the present invention;

[0034] Figure 2 is a comparison of the activity retention rates of anthraquinone compounds under different extraction methods of the present invention;

[0035] Figure 3 It is a comparison of the extraction efficiency under different solid-liquid ratio conditions of the present invention;

[0036] Figure 4 It is the performance trend of the chelating agent of the present invention in terms of recycling;

[0037] Figure 5 is a cost-benefit analysis of the recycling use of the chelating agent of the present invention;

[0038] Figure 6 It is a radar chart of the extraction rates of anthraquinone compounds of different polarities according to the present invention. DETAILED DESCRIPTION

[0039] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. Furthermore, features described in some examples may be combined in other examples.

[0040] At least one embodiment of the present invention discloses a Cassia seed extraction process, comprising a raw material pretreatment step, and the extraction process further comprises the following steps:

[0041] Step 1: Bubble explosion pretreatment: The pretreated Cassia seed powder is mixed with a 70% ethanol aqueous solution at a solid-liquid ratio of 1:5-1:8, and 0.8-1.2 MPa high-pressure nitrogen is introduced for 15-25 minutes to allow the nitrogen to penetrate into the Cassia seed powder particles in the form of microbubbles. The pressure is then quickly reduced to 0.1-0.15 MPa to generate a pressure gradient to cause bubble explosion. This cycle is repeated 3-5 times.

[0042] Step 2: Selective chelation: Add natural ligand as chelating agent to the mixture after bubble explosion pretreatment, and react at 35-40℃ and pH 5.5-6.5 for 40-60 minutes;

[0043] Step 3: Droplet atomization treatment: The chelated mixture is atomized into micron-sized droplets of 15-30 μm under nitrogen protection and circulated for 30-45 minutes;

[0044] Step 4: cyclic microwave heating: the atomized mixture is subjected to intermittent microwave heating at a temperature of 50-55°C for 20-30 minutes;

[0045] Step 5: Phase transition separation: adding a phase transition trigger to the microwave-heated extract, adjusting the pH to 4.0-4.5 to form a two-phase system, and separating to obtain an anthraquinone compound-rich extract and a chelating agent-rich recovery phase;

[0046] Step 6: Chelating agent recovery cycle: The recovered phase is treated to recover the chelating agent and used for the next batch of extraction.

[0047] At least one embodiment of the present invention discloses that in step 1: the pretreated Cassia seed powder is mixed with a 70% ethanol aqueous solution at a solid-liquid ratio of 1:5, and 0.8 MPa high-pressure nitrogen is introduced for 15 minutes to allow the nitrogen to penetrate into the interior of the Cassia seed powder particles in the form of microbubbles, and then the pressure is quickly reduced to 0.1 MPa to generate a pressure gradient to cause the bubbles to burst, and the cycle is repeated 3 times.

[0048] At least one embodiment of the present invention discloses that in step 1: the pretreated Cassia seed powder is mixed with a 70% ethanol aqueous solution at a solid-liquid ratio of 1:6, and 1.0 MPa high-pressure nitrogen is introduced for 20 minutes to allow the nitrogen to penetrate into the interior of the Cassia seed powder particles in the form of microbubbles. Then, the pressure is quickly reduced to 0.13 MPa to generate a pressure gradient to cause the bubbles to burst, and the cycle is repeated 4 times.

[0049] At least one embodiment of the present invention discloses that in step 1: the pretreated Cassia seed powder is mixed with a 70% ethanol aqueous solution at a solid-liquid ratio of 1:8, and 1.2 MPa high-pressure nitrogen is introduced for 25 minutes to allow the nitrogen to penetrate into the interior of the Cassia seed powder particles in the form of microbubbles, and then the pressure is quickly reduced to 0.15 MPa to generate a pressure gradient to cause the bubbles to burst, and the cycle is repeated 5 times.

[0050] At least one embodiment of the present invention discloses that in step 2: a natural ligand is added as a chelating agent to the mixture pre-treated by bubble explosion, and the mixture is reacted at 35° C. and pH 5.5 for 40 minutes.

[0051] At least one embodiment of the present invention discloses that in step 2: a natural ligand is added as a chelating agent to the mixture after bubble explosion pretreatment, and the mixture is reacted at 40° C. and pH 6.5 for 60 minutes.

[0052] At least one embodiment of the present invention discloses that in step 2: a natural ligand is added as a chelating agent to the mixture pre-treated by bubble explosion, and the mixture is reacted at 38° C. and pH 6.0 for 50 minutes.

[0053] At least one embodiment of the present invention discloses that in step 3: the chelated mixture is atomized into micron-sized droplets of 15 μm under nitrogen protection, and the mixture is circulated for 30 minutes.

[0054] At least one embodiment of the present invention discloses that in step 3: the chelated mixture is atomized into micron-sized droplets of 30 μm under nitrogen protection, and the mixture is circulated for 45 minutes.

[0055] At least one embodiment of the present invention discloses that in step 3: the chelated mixture is atomized into micron-sized droplets of 22 μm under nitrogen protection, and the process is circulated for 38 minutes.

[0056] At least one embodiment of the present invention discloses that in step 4: the atomized mixture is subjected to intermittent microwave heating, the temperature is controlled at 50° C., and the time is 20 minutes.

[0057] At least one embodiment of the present invention discloses that in step 4: the atomized mixture is subjected to intermittent microwave heating, the temperature is controlled at 55° C., and the time is 30 minutes.

[0058] At least one embodiment of the present invention discloses that in step 4: the atomized mixture is subjected to intermittent microwave heating, the temperature is controlled at 53° C., and the time is 25 minutes.

[0059] At least one embodiment of the present invention discloses that in step 5: a phase transition trigger is added to the extract after microwave heating, the pH value is adjusted to 4.0, so that the system forms two phases, and the extract rich in anthraquinone compounds and the recovery phase rich in chelating agent are separated.

[0060] At least one embodiment of the present invention discloses that in step 5: a phase transition trigger is added to the extract after microwave heating, the pH value is adjusted to 4.5, so that the system forms two phases, and separation is performed to obtain an extract rich in anthraquinone compounds and a recovery phase rich in chelating agents.

[0061] At least one embodiment of the present invention discloses that in step 5: a phase transition trigger is added to the extract after microwave heating, the pH value is adjusted to 4.3, so that the system forms two phases, and separation is performed to obtain an extract rich in anthraquinone compounds and a recovery phase rich in chelating agents.

[0062] At least one embodiment of the present invention discloses that the bubble explosion pretreatment is performed under a nitrogen protective environment to provide an inert protective environment to prevent the anthraquinone compounds from being oxidized.

[0063] At least one embodiment of the present invention discloses that the natural ligand used as a chelating agent is composed of the following natural substances in parts by weight: 40 parts of citric acid, 25 parts of β-cyclodextrin, 20 parts of glycyrrhizic acid and 10 parts of green tea polyphenols; the added amount of the chelating agent is 3% of the dry weight of Cassia seed.

[0064] At least one embodiment of the present invention discloses that the natural ligand used as a chelating agent is composed of the following natural substances in parts by weight: 55 parts of citric acid, 40 parts of β-cyclodextrin, 10 parts of glycyrrhizic acid and 5 parts of green tea polyphenols; the added amount of the chelating agent is 1.5% of the dry weight of Cassia seed.

[0065] At least one embodiment of the present invention discloses that the natural ligand used as a chelating agent is composed of the following natural substances in parts by weight: 48 parts of citric acid, 32 parts of β-cyclodextrin, 15 parts of glycyrrhizic acid and 8 parts of green tea polyphenols; the added amount of the chelating agent is 2.2% of the dry weight of Cassia seed.

[0066] At least one embodiment of the present invention discloses that the operating parameters of the droplet atomization process include: atomization pressure of 0.5 MPa, atomization nozzle aperture of 50 μm, atomization angle of 60°, a circulation flow rate of 40 L / h, and the temperature of the entire system is maintained at 40°C.

[0067] At least one embodiment of the present invention discloses that the operating parameters of the droplet atomization process include: atomization pressure of 0.8 MPa, atomization nozzle aperture of 80 μm, atomization angle of 90°, a circulation flow rate of 60 L / h, and the entire system temperature is maintained at 45°C.

[0068] At least one embodiment of the present invention discloses that the operating parameters of the droplet atomization process include: atomization pressure of 0.6 MPa, atomization nozzle aperture of 65 μm, atomization angle of 75°, a circulation flow rate of 50 L / h, and the entire system temperature is maintained at 43°C.

[0069] At least one embodiment of the present invention discloses that the microwave frequency of the cyclic microwave heating is 2450 MHz, the microwave power is 300 W, a pulse mode with a working time to stop time ratio of 2:1 is adopted, and the circulation flow rate is 30 L / h.

[0070] At least one embodiment of the present invention discloses that the microwave frequency of the cyclic microwave heating is 2450+50 MHz, the microwave power is 500 W, a pulse mode with a working time to stop time ratio of 2:1 is adopted, and the circulation flow rate is 50 L / h.

[0071] At least one embodiment of the present invention discloses that the microwave frequency of the cyclic microwave heating is 2450-50 MHz, the microwave power is 400 W, a pulse mode with a working time to off time ratio of 2:1 is adopted, and the circulation flow rate is 40 L / h.

[0072] At least one embodiment of the present invention discloses that the phase transition trigger is a sodium acetate solution with a concentration of 30%, and the added amount is 15% of the volume of the extract.

[0073] At least one embodiment of the present invention discloses that the phase transition trigger is a sodium acetate solution with a concentration of 40%, and the added amount is 25% of the volume of the extract.

[0074] At least one embodiment of the present invention discloses that the phase transition trigger is a sodium acetate solution with a concentration of 35%, and the added amount is 20% of the volume of the extract.

[0075] At least one embodiment of the present invention discloses that the chelating agent recovery cycle includes the following processing steps: adjusting the pH value to 7.5, adding 5-8% of the volume of the recovery phase activated carbon to adsorb impurities, stirring at 60°C for 20 minutes, filtering to remove the activated carbon and impurities, and concentrating the treated chelating agent solution to 1.5 times the original concentration.

[0076] At least one embodiment of the present invention discloses that the chelating agent recovery cycle includes the following processing steps: adjusting the pH value to 7.0, adding 5% of the volume of the recovery phase activated carbon to adsorb impurities, stirring at 60°C for 15 minutes, filtering to remove the activated carbon and impurities, and concentrating the treated chelating agent solution to 1.2 times the original concentration.

[0077] At least one embodiment of the present invention discloses that the chelating agent recovery cycle includes the following processing steps: adjusting the pH value to 7.2, adding 6% of the volume of the recovery phase activated carbon to adsorb impurities, stirring at 60°C for 18 minutes, filtering to remove the activated carbon and impurities, and concentrating the treated chelating agent solution to 1.3 times the original concentration.

[0078] Specific implementation examples

[0079] A Cassia seed extraction process comprises the following steps:

[0080] 1. Raw material pretreatment

[0081] The Cassia seed raw material is routinely screened, cleaned, impurities removed, dried to a moisture content of no more than 10%, and crushed to a particle size of 40-80 mesh. This is a common pre-processing step for Chinese herbal medicine extraction, aimed at removing surface impurities and adjusting the particle size to facilitate subsequent extraction.

[0082] 2 Bubble bursting pretreatment

[0083] 2.1 Implementation Methods of Bubble Explosion Pretreatment

[0084] The specific implementation is as follows:

[0085] The pretreated Cassia seed powder is mixed with an extraction solvent at a solid-liquid ratio of 1:5-1:8, wherein the extraction solvent is a 70% ethanol aqueous solution;

[0086] The mixture is placed in a bubble explosion device, which includes a gas injection system, a pressure control system and an explosion reaction chamber;

[0087] High-pressure nitrogen (pressure of 0.8-1.2 MPa) is introduced into the mixture through a gas injection system for 15-25 minutes, so that the nitrogen is evenly dispersed in the mixture in the form of microbubbles and penetrates into the interior of the Cassia seed powder particles;

[0088] After the bubbles are saturated, the system pressure is quickly reduced to 0.1-0.15 MPa to generate a pressure gradient, causing the bubbles that have penetrated into the particles to explode;

[0089] The pressure is cycled 3-5 times, and the high pressure holding time and pressure reduction rate of each cycle can be adjusted according to the batch characteristics of Cassia seed to obtain the best cell wall breaking effect.

[0090] The innovation of this bubble explosion pretreatment step lies in: using the explosion energy of bubbles under a sudden pressure drop to destroy the Cassia seed cell structure from the inside, which is more thorough than traditional mechanical crushing and does not generate local high temperature, thus avoiding thermal damage to the active ingredients; at the same time, using nitrogen as the bubble medium, while breaking the cell wall, it provides an inert protective environment for the system to prevent the oxidation of anthraquinone compounds.

[0091] 2.2 Principle of bubble explosion pretreatment

[0092] Bubble burst pre-treatment works by:

[0093] Pressure penetration: Under high pressure conditions, nitrogen penetrates into the cell structure of Cassia seed in the form of microbubbles;

[0094] Explosion and cell wall breaking: When the pressure drops suddenly, the bubble volume expands rapidly and explodes, generating local shock waves and shear forces, destroying the cell wall and cell membrane structure from the inside;

[0095] Loose tissue: Multiple pressure cycles loosen the tissue structure of Cassia seed, increasing the specific surface area and creating favorable conditions for subsequent chelation and extraction;

[0096] Inert protection: The nitrogen environment inhibits the oxidation reaction of anthraquinone compounds and protects the active ingredients.

[0097] The effect of bubble burst pretreatment can be evaluated by observing the degree of cell wall disruption using a scanning electron microscope. The treated Cassia seed powder showed obvious cell rupture and loose tissue without obvious thermal damage characteristics.

[0098] 3 Selective chelation

[0099] 3.1 Implementation Methods of Selective Chelation

[0100] The specific implementation is as follows:

[0101] Adjust the temperature of the mixture after bubble explosion pretreatment to 35-40°C and the pH value to 5.5-6.5;

[0102] Natural ligands were added to the mixture as selective chelating agents. The amount of the chelating agent added was 2% of the dry weight of Cassia seed. The chelating agent was composed of the following natural substances:

[0103] Citric acid: 50 parts;

[0104] β-cyclodextrin: 32 parts;

[0105] Glycyrrhizic acid: 15 parts;

[0106] Green tea polyphenols: 7 parts;

[0107] Stir gently at 30-50 rpm to avoid vigorous stirring that may damage the chelate complex structure;

[0108] The chelation reaction time is 40-60 minutes, and the whole process is carried out at a constant temperature and in the dark.

[0109] The innovation of this selective chelation step lies in its use of a combination of natural ligands to selectively chelate anthraquinone compounds of varying structural types, forming stable chelate complexes that alter their solubility properties, enabling easier dissolution at lower temperatures. Compared to traditional extraction methods, this step avoids the damage to heat-sensitive anthraquinones caused by high-temperature extraction, while also balancing the extraction efficiency of anthraquinone components of varying polarity.

[0110] 3.2 Principle of selective chelation

[0111] Selective chelation works by:

[0112] Multi-site binding: The carboxyl group in citric acid forms hydrogen bonds with the hydroxyl group in anthraquinone compounds, and glycyrrhizic acid provides hydrophobic binding sites;

[0113] Inclusion effect: β-cyclodextrin forms inclusion complexes with anthraquinone compounds through its spatial structure, changing their solubility;

[0114] Polarity adjustment: Green tea polyphenols provide a variety of phenolic hydroxyl groups, which form corresponding combinations with anthraquinone compounds of different polarities, balancing the extraction efficiency of high, medium and low polarity anthraquinone components;

[0115] Stable protection: The formed chelate complex provides steric protection for anthraquinone compounds, reducing their oxidative degradation during the extraction process.

[0116] Different chelating agent components are selective for different types of anthraquinone compounds: citric acid primarily targets chrysophanol-type anthraquinone compounds, β-cyclodextrin has a high affinity for emodin-type anthraquinone compounds, and glycyrrhizic acid is most effective at chelating auranthus-type anthraquinone compounds. This combined chelating agent achieves comprehensive and balanced extraction of all anthraquinone compounds in Cassia seed.

[0117] 4 Droplet atomization treatment

[0118] 4.1 Implementation of droplet atomization treatment

[0119] The specific implementation is as follows:

[0120] The selectively chelated mixture is transferred to a droplet atomization device, which includes an atomizing nozzle, a circulation pump and an atomizing chamber;

[0121] The operating parameters of the atomization device are set as follows:

[0122] Atomization pressure: 0.5-0.8MPa

[0123] Atomizing nozzle aperture: 50-80μm

[0124] Atomization angle: 60-90°

[0125] Circulation flow rate: 40-60L / h

[0126] Start the atomization device to atomize the mixture into micron-sized droplets (average particle size of 15-30 μm). The atomization process is carried out under a nitrogen protection environment to avoid oxidation of anthraquinone compounds;

[0127] The atomization cycle time is 30-45 minutes, during which the temperature of the entire system is maintained at 40-45°C.

[0128] The innovative nature of this droplet atomization step lies in the fact that by atomizing the extraction mixture into micron-sized droplets, the gas-liquid contact area is greatly increased (the specific surface area increases by approximately 500-800 times), thereby enhancing the bubble bursting effect. This provides a more uniformly heated matrix for subsequent microwave heating, avoiding the mass transfer resistance and uneven heating problems associated with traditional immersion extraction.

[0129] 4.2 Principle of droplet atomization treatment

[0130] Droplet atomization works by the following principles:

[0131] Surface area amplification: Micron-sized droplets greatly increase the gas-liquid contact area, significantly improving mass transfer efficiency;

[0132] Enhanced explosion effect: Microbubbles remaining in the atomization process explode a second time inside the droplets, further destroying the cell structure;

[0133] Uniform dispersion: Atomization allows the chelating agent to come into more complete contact with the anthraquinone compound, thus improving the chelation efficiency;

[0134] Reduced mass transfer resistance: The mass transfer path inside the microdroplets is greatly shortened, which accelerates the diffusion process of the solute.

[0135] Droplet atomization synergizes with the aforementioned bubble bursting and selective chelation: bubble bursting provides the initial wall-breaking conditions, chelation modifies the solubility characteristics of anthraquinone compounds, and droplet atomization maximizes the effects of the first two steps by increasing the interfacial area and shortening the mass transfer path. The microdroplets produced by droplet atomization increase the contact area and reaction rate of the chelation reaction, while chelation modifies the surface tension characteristics of the droplets, making the atomization process more uniform and stable. The two processes form a mutually reinforcing relationship.

[0136] 5-cycle microwave heating

[0137] 5.1 Implementation Methods of Circulating Microwave Heating

[0138] The specific implementation is as follows:

[0139] continuously conveying the atomized mixture to a circulating microwave heating device, which includes a microwave generator, a circulating flow system, and a temperature monitoring system;

[0140] The operating parameters of the microwave heating device are set as follows:

[0141] Microwave frequency: 2450±50MHz

[0142] Microwave power: 300-500W (adjusted according to the amount of material)

[0143] Pulse mode: intermittent, the ratio of working time to stopping time is 2:1

[0144] Circulation flow rate: 30-50L / h

[0145] The microwave heating device is started to intermittently heat the atomized mixture with microwaves. The heating temperature is controlled at 50-55°C, which is lower than the traditional extraction temperature (usually 70-80°C).

[0146] The heating process adopts a circulating flow method to ensure that the mixture is heated evenly and avoid local overheating;

[0147] The microwave heating time is 20-30 minutes, and the entire process is carried out under a nitrogen protection environment.

[0148] The innovation of this cyclic microwave heating step lies in: the use of intermittent, low-temperature, uniform microwave heating method, which forms a synergistic effect with the previous selective chelation, achieving efficient extraction of anthraquinone compounds at lower temperatures; at the same time, the circulating flow method ensures uniform heating of the mixture, avoiding the local overheating problem common in traditional microwave heating, and effectively protecting the activity of heat-sensitive anthraquinone compounds.

[0149] 5.2 Principle of Circulating Microwave Heating

[0150] Circulation microwave heating works by:

[0151] Selective heating: Microwave energy is primarily absorbed by polar molecules such as water molecules, generating heat at the molecular level for rapid and uniform internal heating;

[0152] Thermodynamic promotion: Microwave heating increases the dissolution rate of anthraquinone compounds in the chelated complex and promotes their transfer from the solid phase to the liquid phase;

[0153] Non-thermal effect: The microwave electric field causes the vibration of polar molecules in the cell membrane to intensify, further enhancing cell permeability and promoting the release of active ingredients;

[0154] Synergistic enhancement: It works synergistically with the previous selective chelation to enable anthraquinone compounds to be efficiently dissolved at a lower temperature.

[0155] Circulating microwave heating and the previous droplet atomization treatment form a synergistic effect: the atomized microdroplets provide an ideal heating matrix for microwaves, making the microwave energy more evenly distributed and avoiding the uneven heating problem in traditional immersion extraction; microwave heating provides suitable thermodynamic conditions for the atomized droplets, accelerating the formation of chelate complexes and the dissolution of anthraquinone compounds.

[0156] 6Phase transition separation

[0157] 6.1 Implementation Methods of Phase Transition Separation

[0158] The specific implementation is as follows:

[0159] The extract after microwave heating was collected and cooled to 30°C;

[0160] Slowly add a phase transition trigger (sodium acetate solution, concentration is 30-40%) to the extract, the amount added is 15-25% of the volume of the extract;

[0161] Adjust the pH value of the system to 4.0-4.5, stir gently for 5-10 minutes, and then let it stand for 30-40 minutes to allow the system to form distinct liquid-liquid phases or liquid-solid phases;

[0162] The upper phase (or liquid phase) is rich in anthraquinone compounds, and the lower phase (or solid phase) is rich in chelating agents and other water-soluble impurities;

[0163] The two phases are separated by conventional methods such as centrifugation or reduced pressure filtration to obtain an extract rich in anthraquinone compounds and a recovery phase rich in chelating agent.

[0164] The innovation of this phase-transition separation step lies in leveraging the reversible dissociation of the chelate complex under varying conditions. By adding a phase-transition trigger and adjusting the pH, the chelate bound to the anthraquinone compound undergoes a phase transition, achieving efficient separation of the chelate and anthraquinone compounds. Compared to traditional solvent extraction separation methods, this step does not require large amounts of organic solvents, is environmentally friendly, and is simple to operate.

[0165] 6.2 Principle of Phase Transition Separation

[0166] Phase transition separation works by the following principles:

[0167] Complexation equilibrium destruction: The sodium ions in the phase transition trigger (sodium acetate) form new complexes with the active groups in the chelating agent (such as the carboxyl group of citric acid), destroying the original chelation complex balance;

[0168] Solubility change: pH adjustment changes the ionization state of the chelating agent, causing its solubility to change, facilitating its separation from the solution;

[0169] Phase separation: Solubility changes lead to the formation of two phases in the system, with anthraquinone compounds and chelating agents enriched in different phases respectively;

[0170] Selective distribution: Different types of anthraquinone compounds exhibit different distribution behaviors in the two phases according to their structural characteristics and polarity differences. Selective enrichment of anthraquinone compounds can be achieved by adjusting the phase transition conditions.

[0171] Phase conversion separation is not only an important part of the extraction process, but also a key link in realizing the recycling and reuse of chelating agents. It is one of the core technologies for forming a closed-loop process in this embodiment.

[0172] 7. Chelating agent recovery cycle

[0173] 7.1 Implementation Methods of Chelating Agent Recovery Cycle

[0174] The specific implementation is as follows:

[0175] transferring the chelating agent-rich recovery phase obtained by phase conversion separation into a chelating agent regeneration device;

[0176] The recovered phase was treated as follows:

[0177] Adjust pH to 7.0-7.5

[0178] Add activated carbon (5-8% of the volume of the recovered phase) for impurity adsorption

[0179] Stir at 60℃ for 15-20 minutes

[0180] Filter to remove activated carbon and impurities

[0181] The treated chelating agent solution is concentrated to 1.2-1.5 times the original concentration;

[0182] Conduct activity test on the concentrate and decide whether to add fresh chelating agent ingredients for supplementation based on the activity retention rate;

[0183] Adjust the component ratio of the final chelating agent solution to meet the ratio requirements in 3.1;

[0184] The regenerated chelating agent solution is used for the next batch of extraction process.

[0185] The innovation of this chelating agent recovery cycle lies in the establishment of a complete chelating agent recovery and regeneration process, achieving efficient recycling of the chelating agent, solving the problem of single-use chelating agents in traditional extraction, and significantly reducing production costs and environmental burden. Through activity determination and component replenishment, the stability of the chelating agent's performance is ensured, guaranteeing the sustainability of the extraction process.

[0186] 7.2 Principle of Chelating Agent Recovery Cycle

[0187] The chelate recovery cycle works by the following principles:

[0188] pH adjustment: Neutral pH helps to restore the original configuration and active sites of the chelating agent molecules;

[0189] Impurity removal: Activated carbon adsorption removes impurities such as pigments and polyphenols that bind to the chelating agent during the extraction process, restoring the binding capacity of the chelating agent;

[0190] Activity recovery: Heat treatment and concentration process help to restore the spatial configuration of components such as β-cyclodextrin and restore their inclusion capacity;

[0191] Component balance: By adding fresh components, the component ratio balance of the chelating agent system is maintained to ensure its selective chelation ability for different types of anthraquinone compounds.

[0192] The chelating agent recovery cycle, combined with the previous phase transition separation, forms a closed-loop process, reducing costs and waste emissions, embodying the principles of green chemistry and a circular economy. Experiments have shown that the chelating agent can be recycled more than five times through this process, with a recovery rate exceeding 85%, and its activity remains above 90% of its initial level after five reuses.

[0193] Experimental and test results

[0194] To validate the effectiveness of the proposed phase-transition and selective chelation cycle-assisted droplet atomization-bubble explosion-microwave extraction process for anthraquinone compounds from Cassia seed, a series of experiments and tests were designed and conducted targeting the five key technical effects described above. The following experimental results objectively demonstrate the superiority and innovative nature of this extraction process.

[0195] 1 Extraction efficiency verification experiment

[0196] 1.1 Experimental steps

[0197] Experimental group: The complete process of this embodiment was used to extract anthraquinone compounds from Cassia seeds;

[0198] Control group A: traditional hot water extraction method (90°C, 6 hours);

[0199] Control group B: conventional ethanol reflux extraction method (75°C, 4 hours);

[0200] Control group C: only microwave-assisted extraction (70 °C, 3 h);

[0201] Extract processing: Each group of extracts underwent the same post-processing process (concentration and drying);

[0202] Component analysis: High performance liquid chromatography (HPLC) was used to quantitatively analyze the contents of total anthraquinone compounds and three major anthraquinone compounds (emodin, chrysophanol, and chrysophanol);

[0203] Extraction time record: the total time from the start of extraction to the completion of extract preparation.

[0204] 1.2 Experimental Results

[0205] Table 1 Comparison of extraction efficiency of different extraction methods

[0206]

[0207] According to the experimental results in Table 1, compared with the traditional method, the extraction process of this embodiment: 1) the extraction rate of total anthraquinone compounds is increased by 41.5%-54.4%; 2) the extraction time is reduced by 16.7%-58.3%; 3) the extraction rates of major anthraquinone compounds (emodin, chrysophanol, and chrysophanol) are increased by 19.5%-58.1%, 30.5%-44.2%, and 30.8%-51.1%, respectively.

[0208] These results strongly prove that this extraction process significantly improves the extraction efficiency of anthraquinone compounds from Cassia seed and greatly shortens the extraction time.

[0209] 2 Low temperature activity verification experiment

[0210] 2.1 Experimental steps

[0211] Experimental group: using the extraction process of this embodiment, the extraction temperature was controlled at 50-55°C;

[0212] Control group A: using traditional hot water extraction method (90℃);

[0213] Control group B: conventional ethanol reflux extraction method (75°C);

[0214] Control group C: modified microwave-assisted extraction method (65°C);

[0215] Extraction of active ingredients: Each group extracted anthraquinone compounds from the same batch of Cassia seeds samples;

[0216] Activity assay: The biological activity of the extract was evaluated by three methods: antioxidant activity assay (DPPH free radical scavenging rate), anti-inflammatory activity assay (NO production inhibition rate) and cell viability assay (MTT assay);

[0217] Determination of the content of heat-sensitive components: HPLC method was used to quantitatively determine the content of aloe-emodin, which is highly heat-sensitive, and its retention rate.

[0218] 2.2 Experimental Results

[0219] Table 2 Activity retention of anthraquinone compounds at different extraction temperatures

[0220]

[0221] Figure 1 : Relationship between different extraction temperatures and aloe-emodin retention rate.

[0222] Figure 2 : Comparison of activity retention rates of anthraquinone compounds under different extraction methods.

[0223] According to Table 2 and Figure 1 、 Figure 2 The experimental results show that the low-temperature extraction process of this embodiment performs outstandingly in maintaining the activity of anthraquinone compounds: 1) Compared with the traditional high-temperature extraction method, the DPPH scavenging rate of this process is increased by 9.3%-35.2%, the NO inhibition rate is increased by 10.2%-37.5%, and the cell viability is increased by 7.6%-25.8%; 2) For aloe-emodin, which is highly heat-sensitive, the retention rate of this process reaches 91.8%, which is 32.1% higher than the traditional hot water extraction method, 18.3% higher than the ethanol reflux method, and 10.5% higher than the microwave-assisted extraction method; 3) There is a significant linear negative correlation between the extraction temperature and the aloe-emodin retention rate, which verifies the significant effect of low-temperature extraction of this process on protecting heat-sensitive anthraquinone compounds.

[0224] These results fully demonstrate that the low-temperature extraction process of this embodiment can effectively protect the biological activity of anthraquinone compounds, especially has a significant protective effect on components with high heat sensitivity.

[0225] 3. Solvent usage reduction verification experiment

[0226] 3.1 Experimental steps

[0227] Experimental design: Five solid-to-liquid ratio gradients (1:5, 1:8, 1:10, 1:12, and 1:15) were set up, and the process of this embodiment was compared with the traditional ethanol reflux extraction method.

[0228] Experimental group: The complete process of this embodiment was adopted, and extraction was performed according to various solid-liquid ratios;

[0229] Control group: conventional ethanol reflux extraction method was used with the same solid-liquid ratio;

[0230] Number of extractions: To ensure sufficient extraction, the experimental group used one extraction, while the control group used three extractions;

[0231] Determination of solvent recovery rate: Determination of the proportion of solvent that can be recovered and reused after extraction;

[0232] Evaluation of extraction efficiency: HPLC method was used to determine the extraction rate of total anthraquinone compounds under various solid-liquid ratio conditions;

[0233] Cost accounting: Calculate the solvent consumption cost of each extraction method under the same extraction efficiency conditions.

[0234] 3.2 Experimental Results

[0235] Table 3 Comparison of extraction efficiency and solvent consumption under different solid-liquid ratios

[0236]

[0237] Figure 3 : Comparison of extraction efficiency under different solid-liquid ratios.

[0238] According to Table 3 and Figure 3 The experimental results show that the present embodiment has significant advantages in terms of solvent usage: 1) Under the same solid-liquid ratio conditions, the extraction rate of the present process is significantly higher than that of the traditional method, averaging 98.6% higher; 2) Considering that the traditional method requires three extractions, the actual solvent usage of the present process is only 33.3% of that of the traditional method, and the solvent usage is reduced by 66.7%; 3) The extraction efficiency of the present process under a solid-liquid ratio of 1:5 has exceeded the extraction efficiency of the traditional method under a solid-liquid ratio of 1:15, indicating that the present process can use less solvent to achieve the same or even better extraction effect as the traditional method; 4) The solvent utilization efficiency (ratio of extraction rate to solvent usage) of the present process is 2.6-3.0 times that of the traditional method, reflecting the significant solvent saving effect of the present process.

[0239] These results fully verify that this embodiment achieves a significant reduction in solvent usage through the synergistic effect of droplet atomization and bubble explosion, selective chelation and other technologies, and has obvious economic and environmental advantages.

[0240] 4 Chelating agent recycling verification experiment

[0241] 4.1 Experimental steps

[0242] Experimental Design: Five consecutive batches of anthraquinone compound extraction experiments were designed to evaluate the recovery rate and reusability of the chelating agent;

[0243] Chelating agent composition: a chelating agent solution (45% citric acid, 35% β-cyclodextrin, 15% glycyrrhizic acid, 5% green tea polyphenols) was prepared according to the formula of this embodiment;

[0244] Extraction process: Each batch is extracted according to the complete process of this embodiment, and the recovered phase rich in chelating agent is collected;

[0245] Chelating agent regeneration: Process the recovered phase according to the chelating agent recovery cycle steps described in Section 4.7.1;

[0246] Recycling: The regenerated chelating agent is used for the next batch of extraction, and the insufficient part is supplemented with fresh chelating agent components;

[0247] Performance evaluation: Chelating agent recovery, activity retention and extraction efficiency were measured for each batch;

[0248] Cost Analysis: Calculate the cost of reusable versus single-use chelating agents.

[0249] 4.2 Experimental Results

[0250] Table 4 Evaluation of chelating agent recycling performance

[0251]

[0252] Figure 4 : Performance trends of chelating agents in recycling applications.

[0253] Figure 5 : Cost-benefit analysis of chelating agent recycling.

[0254] According to Table 5 and Figure 6 The experimental results show that the chelating agent recycling system of this embodiment shows excellent performance: 1) the chelating agent recovery rate is stable at a high level of 85%-87%, and it still remains at 85.2% after 5 cycles; 2) the chelating agent activity retention rate decreases slightly with the number of cycles, but it still remains at a high level of 90.4% after 5 cycles; 3) the total anthraquinone compound extraction rate decreases slightly with the number of cycles, and the extraction rate after 5 cycles is 4.29%, which is only 3.2% lower than the 4.43% of the first extraction; 4) the amount of fresh chelating agent replenished is maintained between 14% and 18%, indicating that only a small amount of fresh chelating agent needs to be added in each batch to maintain system performance; 5) cost analysis shows that the single-batch cost of the chelating agent is reduced by 82.6%-85.8% after recycling. After 5 batches, the cumulative cost savings reach 65.5%.

[0255] These results fully demonstrate that this embodiment achieves efficient recycling of chelating agents through phase conversion separation and chelating agent recovery and circulation processes, significantly reduces production costs, and reduces waste emissions, reflecting the concepts of green chemistry and circular economy.

[0256] 5. Full component balanced extraction verification experiment

[0257] 5.1 Experimental steps

[0258] Experimental group: The complete process of this embodiment was used to extract anthraquinone compounds from Cassia seeds;

[0259] Control group A: using traditional hot water extraction method;

[0260] Control group B: conventional ethanol reflux extraction method;

[0261] Control group C: ultrasound-assisted extraction method;

[0262] Evaluation of component extraction efficiency: High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to quantitatively analyze 14 major anthraquinone compounds (divided into three polarity types: high, medium, and low) in Cassia seed.

[0263] Evaluation of component extraction balance: Calculate the extraction rate and differences of anthraquinone compounds of different polarity types;

[0264] Evaluation of component ratio: Compare the ratio of various anthraquinone components in the extract with the natural distribution ratio in Cassia seed.

[0265] 5.2 Experimental Results

[0266] Table 5 Comparison of extraction rates of anthraquinone compounds with different polarities

[0267]

[0268] Figure 6 : Radar chart of the extraction rate of anthraquinone compounds with different polarities.

[0269] According to Table 5 and Figure 6 The experimental results show that the present embodiment has significant advantages in the balanced extraction of all components: 1) the extraction rates of high, medium and low polar anthraquinone compounds reached 4.35%, 4.48% and 4.13% respectively, and the maximum extraction rate difference was only 8.5%, while the difference of the traditional method was 28.9%-66.8%; 2) in particular, the extraction rate of low polar anthraquinone compounds was increased by 222.7% compared with the hot water extraction method and 60.1% compared with the ultrasonic-assisted extraction; 3) the proportion of various anthraquinone components in the extract was 94.2% consistent with the natural distribution of Cassia seed, while the consistency of the traditional extraction method was 58.6%-82.5%; 4) the proportion of high, medium and low polar anthraquinone compounds in the extract of this process (33.6%: 34.6%: 31.8%) was closest to the natural distribution of Cassia seed (34.2%: 35.1%: 30.7%).

[0270] These results fully demonstrate that this embodiment achieves balanced extraction of anthraquinone compounds of different polarities in Cassia seed through combined selective chelating agent and phase conversion separation technology. The obtained extract more comprehensively retains the natural proportion of anthraquinone compounds in Cassia seed, which is conducive to maintaining its overall medicinal efficacy.

[0271] The above describes an embodiment of the present invention, but this embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make more forms of equivalent embodiments based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. A Cassia seed extraction process, comprising a raw material pretreatment step, characterized in that: The extraction process further comprises the following steps: Step 1: Bubble explosion pretreatment: The pretreated Cassia seed powder is mixed with a 70% ethanol aqueous solution at a solid-liquid ratio of 1:5-1:8, and 0.8-1.2 MPa high-pressure nitrogen is introduced for 15-25 minutes to allow the nitrogen to penetrate into the Cassia seed powder particles in the form of microbubbles. The pressure is then quickly reduced to 0.1-0.15 MPa to generate a pressure gradient to cause bubble explosion. This cycle is repeated 3-5 times. Step 2: Selective chelation: Add natural ligand as chelating agent to the mixture after bubble explosion pretreatment, and react at 35-40℃ and pH 5.5-6.5 for 40-60 minutes; Step 3: Droplet atomization treatment: The chelated mixture is atomized into micron-sized droplets of 15-30 μm under nitrogen protection and circulated for 30-45 minutes; Step 4: cyclic microwave heating: the atomized mixture is subjected to intermittent microwave heating at a temperature of 50-55°C for 20-30 minutes; Step 5: Phase transition separation: adding a phase transition trigger to the microwave-heated extract, adjusting the pH to 4.0-4.5 to form a two-phase system, and separating to obtain an anthraquinone compound-rich extract and a chelating agent-rich recovery phase; Step 6: Chelating agent recovery cycle: The recovered phase is treated to recover the chelating agent and used for the next batch of extraction.

2. A Cassia seed extraction process according to claim 1, characterized in that, The bubble explosion pretreatment is carried out in a nitrogen protective environment to provide an inert protective environment to prevent the anthraquinone compounds from being oxidized.

3. A Cassia seed extraction process according to claim 1, characterized in that, The natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 40-55 parts of citric acid, 25-40 parts of beta-cyclodextrin, 10-20 parts of glycyrrhizic acid and 5-10 parts of green tea polyphenols; the added amount of the chelating agent is 1.5-3% of the dry weight of cassia seed.

4. A Cassia seed extraction process according to claim 1, characterized in that, The natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 40 parts of citric acid, 25 parts of beta-cyclodextrin, 20 parts of glycyrrhizic acid and 10 parts of green tea polyphenols; the added amount of the chelating agent is 3% of the dry weight of cassia seed.

5. A Cassia seed extraction process according to claim 1, characterized in that, The natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 55 parts of citric acid, 40 parts of beta-cyclodextrin, 10 parts of glycyrrhizic acid and 5 parts of green tea polyphenols; the added amount of the chelating agent is 1.5% of the dry weight of cassia seed.

6. A Cassia seed extraction process according to claim 1, characterized in that, The natural ligand as a chelating agent is composed of the following natural substances in parts by weight: 48 parts of citric acid, 32 parts of beta-cyclodextrin, 15 parts of glycyrrhizic acid and 8 parts of green tea polyphenols; the added amount of the chelating agent is 2.2% of the dry weight of cassia seed.

7. The Cassia seed extraction process according to claim 1, characterized in that: The operating parameters of the droplet atomization process include: atomization pressure 0.5-0.8 MPa, atomization nozzle aperture 50-80 μm, atomization angle 60-90°, circulation flow rate 40-60 L / h, and the temperature of the entire system maintained at 40-45°C.

8. The Cassia seed extraction process according to claim 1, characterized in that: The microwave frequency of the cyclic microwave heating is 2450±50 MHz, the microwave power is 300-500 W, a pulse mode with a working time to stop time ratio of 2:1 is adopted, and the circulation flow rate is 30-50 L / h.

9. The Cassia seed extraction process according to claim 1, characterized in that: The phase conversion trigger is a sodium acetate solution with a concentration of 30-40%, and the added amount is 15-25% of the volume of the extract.

10. The Cassia seed extraction process according to claim 1, characterized in that: The chelating agent recovery cycle includes the following treatment steps: adjusting the pH value to 7.0-7.5, adding 5-8% of the volume of the recovery phase activated carbon to adsorb impurities, stirring at 60°C for 15-20 minutes, filtering to remove the activated carbon and impurities, and concentrating the treated chelating agent solution to 1.2-1.5 times the original concentration.

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