Equipment and method for integrally preparing perilla leaf extract

Abstract

The invention relates to equipment and a method for integrally preparing a perilla leaf extract, and belongs to the technical field of perilla leaf processing. The device and the method for preparing the perilla leaf extract through integration of infrared-vacuum freeze-drying-ultrasonic-assisted deep eutectic solvent extraction have the advantages of integration and automatic extraction, and bioactive components of the perilla leaf extract are reserved to the maximum extent. The method comprises the following steps: carrying out enzyme deactivation treatment on perilla leaves by utilizing infrared pretreatment, exciting conversion of active substances, drying the perilla leaves by adopting a low-temperature vacuum freeze-drying technology, increasing the content of bioactive substances in the perilla leaf extract, crushing the perilla leaves by adopting a vibrating screen, and extracting the perilla leaf powder by adopting an ultrasonic-assisted eutectic solvent, so that the content of the bioactive substances in the perilla leaf extract is increased. And an automatic drying-crushing-extracting process can be realized.

Description

Technical Field

[0001] This invention relates to an integrated equipment and method for preparing perilla leaf extract, which is used for processing perilla leaves and belongs to the field of food processing technology. Background Technology The "Huangdi Neijing Taisu" proposes the concept of "medicine and food sharing the same origin," stating that "when eaten on an empty stomach, it is food; when eaten by a patient, it is medicine." Perilla (Perilla frutescens) is an annual herb belonging to the Lamiaceae family. It is a medicinal and edible herb. Perilla leaves, seeds, and stems have been included in the 2010 edition of the Pharmacopoeia of the People's Republic of China. Perilla leaves contain a variety of components, mainly including volatile oils, anthocyanins, flavonoids, phenolic acids, triterpenoids, amino acids, and sugars, which have anti-inflammatory, anti-allergic, antibacterial, and anti-tumor effects.

[0002] There are many ways to dry perilla leaves. Traditional methods include sun-drying and shade-drying, but these require a large area, are easily limited by climate and season, and are susceptible to bacterial and mold contamination during the drying process, failing to guarantee the hygiene and quality of the food. Hot air drying, also known as "convection drying," has low operating costs and requires less investment, making it one of the most widely used methods in the dried goods industry. However, prolonged high-temperature drying can lead to a decline in product quality. Mid- and short-wave infrared drying is a newer drying method. Its main principle is that during mid- and short-wave infrared radiation heating, when the infrared emission wavelength matches the absorption wavelength of water, the infrared radiation is quickly absorbed by water molecules, converting into thermal motion of the water molecules. Simultaneously, the water molecules accelerate, causing the material to lose moisture. Mid- and short-wave infrared drying is characterized by its short wavelength, strong penetration, and rapid heating. However, current research on mid- and short-wave infrared drying is limited. Vacuum freeze drying, or freeze drying for short, has advantages such as low drying temperature, good product puffing and rehydration properties, effective sterilization in an oxygen-deficient environment, and reduced product oxidation. However, vacuum freeze drying requires a long time. Combining infrared drying pretreatment with vacuum drying can reduce the loss of active substances in perilla leaves and reduce the energy consumption when using vacuum freeze drying alone.

[0003] Extraction of active ingredients from perilla leaves includes hot water extraction, enzymatic extraction, ultrasound-assisted extraction, and microwave-assisted extraction. Hot water extraction suffers from long extraction times and low efficiency. While enzymatic extraction can improve extraction rates by disrupting plant cell wall structures, the process is time-consuming and enzyme preparations are expensive, limiting its large-scale application. Microwave and ultrasound-assisted extraction technologies have shown significant improvements in extraction efficiency and time, and related research is increasing, but challenges remain, such as solvent residue and the easy degradation of heat-sensitive components. Ultrasound-assisted low-eutectic solvent extraction (DES) is a green and efficient novel extraction method. Using a low-eutectic solvent as the extraction medium and combining it with the cavitation effect of ultrasound, it offers significant advantages, including being environmentally friendly, highly designable, having good solubility for target components, low operating temperature, and high extraction efficiency. This technology is particularly suitable for raw materials containing heat-sensitive and easily oxidized active ingredients. The synergistic effect of DES and ultrasound can achieve high-quality, high-yield extraction of active ingredients from perilla leaves, demonstrating significant technical advantages and application prospects.

[0004] However, there are no reports on equipment for preparing perilla leaf extract using an integrated infrared-vacuum freeze-drying-ultrasound-assisted low eutectic solvent extraction device. Summary of the Invention

[0005] To address the problems of fragmented processes, destruction of active ingredients, and organic solvent contamination in traditional perilla leaf extraction processes, this invention creatively integrates infrared pretreatment, vacuum freeze-drying, and ultrasound-assisted eutectic solvent extraction technologies into a single integrated equipment. Through a fully automated, closed process, continuous, low-temperature, and efficient preparation of perilla leaves from raw materials to highly active extracts is achieved. This not only significantly improves the extraction rate and purity of key active ingredients such as polyphenols, rosmarinic acid, and perillaldehyde, but also, by combining the synergistic pretreatment mechanism of infrared-freeze-drying with the efficient dissolution characteristics of eutectic solvents, extracts with high antioxidant activity are obtained. This lays a solid technological foundation for developing high-quality, highly stable functional raw materials from perilla leaves.

[0006] This invention utilizes infrared pretreatment to inactivate enzymes in perilla leaves and simultaneously stimulate the transformation of active substances. It also employs low-temperature vacuum freeze-drying technology to dry the perilla leaves, thereby increasing the content of bioactive substances in the perilla leaf extract. Furthermore, it utilizes a vibrating screen to crush the perilla leaves and ultrasound-assisted extraction of perilla leaf powder using a low-eutectic solvent, thus achieving an automated drying-crushing-extraction process.

[0007] The first objective of this invention is to provide an integrated apparatus for preparing perilla leaf extract, comprising a main body, wherein the interior of the main body is divided into an upper layer and a lower layer by a high-vacuum insert valve; The upper layer is provided with a material trough for holding materials and a propeller extending downward into the material trough. The bottom of the material trough is provided with a first material outlet, and a sealing gate valve is installed at the first material outlet. The inner wall of the upper layer of the main body is also equipped with infrared lamps arranged around the material trough. The lower layer is provided with a vibrating screen frame, and the vibrating screen frame is equipped with a vibrating screen mesh. The bottom layer of the vibrating screen mesh is provided with a second material outlet, and the second material outlet is connected to a magnetic sealing joint. An electric push rod and a vibrating motor are connected below the vibrating screen frame. A condensation trap is also installed at the bottom of the vibrating screen frame, and a water outlet is provided at the bottom of the condensation trap. The second material outlet is connected in sequence to the powder conveying and metering system and the flat plate sealed filter via a sealed pipe; the powder conveying and metering system includes a perilla powder silo, a material weighing trough, and a weighing sensor connected in sequence; the material weighing trough is flexibly connected to the high-precision weighing sensor, and its bottom outlet is directly connected to the feed inlet of the extraction vessel via an air-operated ball valve; the air-operated ball valve is connected to the air compressor of the pulse backflushing system via a two-position five-way solenoid valve; The lower layer is also equipped with a vacuum system, and the condenser is connected to the refrigeration system through pipes.

[0008] Furthermore, the second material outlet is connected to the perilla powder silo via a sealed pipe; a rotary valve is provided on the sealed pipe, a set of filters is provided on the top of the perilla powder silo, and the vacuum perilla powder silo is connected to an oil-free vacuum pump via a vacuum pipe; at the same time, a compressed air pipe is also connected to the clean side of the filter, a pulse solenoid valve is provided on the compressed air pipe, and the compressed air pipe is connected to an air compressor to form a pulse backflushing system; The flat-plate sealed filter includes a filter plate assembly, a hydraulic closure system, and an inflatable diaphragm pressing plate located in the filter plate assembly; the feed inlet of the flat-plate sealed filter is connected to the bottom outlet of the ultrasonic extraction vessel; the liquid outlet of the flat-plate sealed filter is connected to the extract storage tank; the residue outlet of the flat-plate sealed filter is connected to the residue collection box; the flat-plate sealed filter is also equipped with a compressed gas interface, which is connected to an air compressor through a pipeline to provide pressing power to the inflatable diaphragm.

[0009] Furthermore, the connection between the main body and the stirring motor is a fixed connection, and the propellers are symmetrically distributed along the vertical center line of the stirring motor; a controller is provided on the front surface of the main body, the controller is electrically connected to the stirring motor, and the controller controls the rotation of the stirring motor.

[0010] Furthermore, the infrared lamps are symmetrically distributed on the four inner walls of the main body, and the controller is electrically connected to the infrared lamps, controlling the irradiation time and irradiation power of the infrared lamps.

[0011] Furthermore, the material trough is provided with evenly spaced round holes around its perimeter, so that the infrared light emitted by the infrared lamps can be evenly irradiated onto the material.

[0012] Furthermore, the sealed gate valve is electrically connected to the controller, which controls the opening and closing of the sealed gate valve.

[0013] Furthermore, a high-vacuum gate valve is provided in the middle of the main body. The high-vacuum gate valve is equipped with a sealing ring. The valve body is made of 304 stainless steel, the valve plate is made of stainless steel, and elastic sealing rings are inlaid on both sides of the gate. The sealing rings are made of perfluoroether rubber. The high-vacuum gate valve is electrically connected to the controller, and the controller controls the high-vacuum gate valve to start or close the valve.

[0014] Furthermore, the vibrating screen frame is equipped with a dust cover, which has a porous structure with a circular hole in the middle having a radius larger than that of the material outlet. The vibrating screen mesh has three layers, with the mesh size decreasing from top to bottom. A strip support frame is installed on the outside of the vibrating screen frame, which is connected to the vibrating motor. An electric push rod is also connected to the bottom of the vibrating screen frame. Both the vibrating motor and the electric push rod are electrically connected to the controller, which controls their switching.

[0015] Furthermore, the lower layer of the main body is a vacuum-sealed environment. The vacuum system and refrigeration system are located behind the supercritical carbon dioxide extraction device on the outside of the main body. The vacuum system is connected to the side of the lower layer through pipes. The hatch connection adopts a standard CF flange interface. The standard CF flange interface is clamped with a clamp. The condenser trap in the lower layer is equipped with a condenser coil. The condenser coil is sealed to the bulkhead by welding and connected to the refrigeration system. The lower material outlet is equipped with an automatic switch valve and connected to a magnetic sealing joint. The magnetic sealing joint is equipped with a ring magnet and a sealing ring. One end of the magnetic sealing joint is connected to a food-grade hose. The food-grade hose is connected to a stainless steel fixed pipeline. The stainless steel fixed pipeline is connected to the perilla powder silo via a rotary valve. Valves are installed on the pipelines before and after the rotary valve. The weighing sensor and the control component of the pneumatic ball valve, a two-position five-way solenoid valve, are electrically connected to the controller. This controls the powder to enter the material weighing tank from the perilla powder silo for weighing. After the weighing reaches the target, the pneumatic ball valve is opened, allowing the powder to fall vertically into the extraction vessel by gravity. This achieves rapid and sealed feeding of perilla leaf powder into the extraction vessel. The paddle agitator, ultrasonic generator, high-precision constant temperature water bath, and flat sealed filter in the extraction vessel are electrically connected to the controller, which controls their switching and parameter settings.

[0016] The second objective is to provide a method for preparing perilla leaf extract using an integrated apparatus, comprising the following steps: Step 1: Take fresh, unrotten perilla leaves, wash and drain them; open the sealing cover on top of the extraction tank, spread the washed fresh perilla leaves evenly in the material tank, and then replace the sealing cover to ensure the cavity is sealed; start the stirring motor, drive the propeller to turn the perilla leaves over so that they are heated evenly, and start the infrared lamp and the ring infrared lamp at the same time to perform infrared pretreatment on the perilla leaves, effectively removing some moisture and activating the active ingredients; Step Two: After infrared treatment, the system automatically enters the cooling stage. Once the material temperature drops to room temperature, the sealed gate valve and the high-vacuum gate valve open sequentially, and the perilla leaves fall into the lower vibrating screen frame along the material outlet; subsequently, the valves close, and a sealed freeze-drying environment is formed in the lower layer; the refrigeration system and vacuum system start up, rapidly reducing the chamber temperature and establishing high-vacuum conditions, and the moisture in the perilla leaves sublimates directly under the frozen state and is captured by the condenser trap; Step 3: After the freeze-drying process is completed, the system enters standby mode. At this time, the vibration motor is started, and the freeze-dried perilla leaves are crushed by collision on the screen through high-frequency vibration; the powder that reaches the predetermined particle size falls through the screen into the bottom collection area, and the coarse material that does not meet the requirements continues to be crushed; after the crushing is completed, the electric push rod pushes the vibrating screen frame to tilt towards the material outlet side, so that the powder is concentrated near the outlet. Step 4: The magnetic sealing joint at the material outlet automatically engages and locks, forming a sealed conveying channel; the material outlet and rotary valve are opened in sequence, the vacuum pump is started, and under the action of negative pressure airflow, the perilla powder is safely conveyed through the sealed pipeline to the powder silo of the eutectic solvent extraction system; Step 5: After the conveying is completed, close the valve. The eutectic solvent in the DES storage tank is accurately conveyed to the extraction vessel through the flow meter. At the same time, the material weighing tank at the bottom of the powder silo completes the quantitative weighing of the perilla powder through the high-precision weighing sensor. The air-operated ball valve is opened to send the powder into the extraction vessel. During the extraction process, the ultrasonic auxiliary system and the stirrer run synchronously to enhance the mass transfer effect. Step 6: After extraction, the mixture enters a flat plate sealed filter to achieve solid-liquid separation. The crude perilla extract enters the extract storage tank through the liquid outlet, while the residue is discharged into the collection box through the residue outlet. Finally, the crude extract is purified using D101 macroporous resin to obtain perilla leaf extract.

[0017] The beneficial effects of this invention are: This invention organically integrates infrared pretreatment, vacuum freeze-drying, and ultrasound-assisted low-eutectic solvent extraction technologies to form a highly efficient continuous process and equipment. This design avoids material transfer losses and contamination risks associated with traditional multi-step separation operations, achieving integrated preparation from raw materials to extracts. This significantly improves production efficiency and automation levels, laying a solid foundation for large-scale production.

[0018] This integrated method significantly improves the quality of perilla leaf extract. The combination of infrared and freeze-drying technologies rapidly reduces moisture while perfectly preserving the heat-sensitive and volatile active ingredients in perilla leaves under low-temperature, anaerobic conditions, preventing their degradation and oxidation. Ultrasonic-assisted low-eutectic solvent extraction technology further ensures high quality, high yield, and high efficiency of the extract.

[0019] The integrated design of infrared-freeze-ultrasound-assisted low-eutectic solvent extraction creates a highly efficient synergistic effect, improving extraction efficiency and economic benefits. The entire system can be precisely programmed and controlled via a central controller, allowing for precise control of key parameters such as infrared power, freeze-drying temperature and vacuum level, ultrasonic power, ultrasonic time, extraction temperature, and material-to-liquid ratio. This ensures good process reproducibility and stable product quality. The integrated design enables continuous material transfer and processing within a closed system, reducing material exposure and transfer losses in intermediate stages, as well as energy losses from repeated heating and cooling, thus improving production efficiency and economic benefits.

[0020] This method has significant advantages in energy conservation, emission reduction, and environmental protection. Infrared pretreatment significantly shortens the subsequent energy-intensive freeze-drying cycle, reduces overall operating costs, and is a highly efficient and green production process. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the method of the present invention.

[0022] Figure 2 This is a schematic diagram of the overall internal structure of the integrated equipment in one embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of another overall internal structure of the integrated equipment in one embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the overall external structure of the integrated equipment in one embodiment of the present invention.

[0025] Figure 5 This is a cross-sectional schematic diagram of an integrated device according to one embodiment of the present invention.

[0026] In the diagram, 1. Main body; 2. Stirring motor; 4. Propeller; 7. Infrared lamp; 8. Material trough; 9. First material outlet; 10. Sealed gate valve; 11. High vacuum gate valve; 12. Dust cover; 13. Vibrating screen frame; 14. Vibrating screen mesh; 15. Electric push rod; 16. Vibrating motor; 17. Second material outlet; 18. Magnetic sealing joint; 19. Sealed pipe; 20. Refrigeration system; 21. Vacuum system; 22. Condensate trap; 23. Water outlet; 24. Rotary valve; 25. 26. Pulse solenoid valve; 27. Filter; 28. Perilla powder silo; 29. ​​Material weighing tank; 30. Oil-free vacuum pump; 31. Weighing sensor; 32. Air-operated ball valve; 33. Two-position five-way solenoid valve; 37. Air compressor; 39. Extraction vessel; 40. Paddle agitator; 42. Ultrasonic generator; 44. High-precision constant temperature water bath; 45. Flat plate sealed filter; 46. Extraction liquid storage tank; 47. Liquid outlet; 48. Residue collection box; 49. Residue outlet; 50. Controller. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] In this invention, the terms "first" and "second" are used only to distinguish similar components / parts in different positions or with different characteristics, and have no other limiting meaning; "upper" refers to the direction in which each component is away from the ground, and "lower" refers to the direction in which each component is away from the ground.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] The present invention provides an integrated equipment for preparing perilla leaf extract, comprising a main body 1, wherein the interior of the main body 1 is divided into an upper layer and a lower layer by a high vacuum gate valve 11; The upper layer is provided with a material trough 8 for holding materials and a propeller 4 extending downward into the material trough 8. The bottom of the material trough 8 is provided with a first material outlet 9. A sealing gate valve 10 is installed at the first material outlet 9. The inner wall of the upper layer of the main body 1 is also provided with infrared lamp tubes 7 arranged around the material trough 8. The lower layer is provided with a vibrating screen frame 13, and a vibrating screen mesh 14 is installed inside the vibrating screen frame 13. A second material outlet 17 is provided at the bottom of the vibrating screen mesh 14, and the second material outlet 17 is connected to a magnetic sealing joint 18. An electric push rod 15 and a vibration motor 16 are connected below the vibrating screen frame 13. A condensation trap 22 is also installed at the bottom of the vibrating screen frame 13, and a water outlet 23 is provided at the bottom of the condensation trap 22. The second material outlet 17 is connected in sequence to the powder conveying and metering system and the flat plate sealed filter 45 via a sealed pipe 19; the powder conveying and metering system includes a perilla powder silo 27, a material weighing trough 29, and a weighing sensor 31 connected in sequence; the material weighing trough 29 is flexibly connected to the high-precision weighing sensor 31, and its bottom outlet is directly connected to the feed inlet of the extraction vessel 39 via an air-operated ball valve 32; the air-operated ball valve 32 is connected to the air compressor 37 of the pulse backflushing system via a two-position five-way solenoid valve 33; The lower layer is also equipped with a vacuum system 21, and the condenser 22 is connected to the refrigeration system 20 through a pipe.

[0032] In some embodiments, the second material outlet 17 is connected to the perilla powder silo 27 via a sealed pipe 19; a rotary valve 24 is provided on the sealed pipe 19, a set of filters 26 is provided on the top of the perilla powder silo 27, and the vacuum perilla powder silo 27 is connected to an oil-free vacuum pump 30 via a vacuum pipe; at the same time, a compressed air pipe is also connected to the clean side of the filter 26, a pulse solenoid valve 25 is provided on the compressed air pipe, and the compressed air pipe is connected to an air compressor 37 to form a pulse backflushing system; The flat-plate sealed filter 45 includes a filter plate assembly, a hydraulic closure system, and an inflatable diaphragm pressing plate located in the filter plate assembly; the feed inlet of the flat-plate sealed filter 45 is connected to the bottom outlet of the extraction vessel 39; the liquid outlet 47 of the flat-plate sealed filter 45 is connected to the extract storage tank 46; the residue outlet 49 of the flat-plate sealed filter 45 is connected to the residue collection box 48; the flat-plate sealed filter 45 is also equipped with a compressed gas interface, which is connected to an air compressor 37 through a pipeline to provide pressing power to the inflatable diaphragm.

[0033] Furthermore, the connection between the main body 1 and the stirring motor 2 is a fixed connection, and the propellers 4 are symmetrically distributed along the vertical center line of the stirring motor 2; a controller 50 is provided on the front surface of the main body 1, the controller 50 is electrically connected to the stirring motor 2, and the controller 50 controls the rotation of the stirring motor 2.

[0034] Furthermore, the infrared lamps 7 are symmetrically distributed on the four inner walls of the main body 1, and the controller 50 is electrically connected to the infrared lamps 7. The controller 50 controls the irradiation time and irradiation power of the infrared lamps 7.

[0035] Furthermore, the material trough 8 is provided with evenly spaced round holes around its perimeter, so that the infrared light emitted by the infrared lamp tube 7 can evenly illuminate the material.

[0036] Furthermore, the sealed gate valve 10 is electrically connected to the controller 50, and the controller 50 controls the opening and closing of the sealed gate valve 10.

[0037] Furthermore, a high-vacuum gate valve 11 is provided in the middle of the main body 1. The high-vacuum gate valve 11 is equipped with a sealing ring. The valve body is made of 304 stainless steel, the valve plate is made of stainless steel, and elastic sealing rings are inlaid on both sides of the gate plate. The sealing rings are made of perfluoroether rubber. The high-vacuum gate valve 11 is electrically connected to the controller 50. The controller 50 controls the high-vacuum gate valve 11 to start or close the valve.

[0038] Furthermore, the vibrating screen frame 13 is equipped with a dust cover 12, which has a porous structure with a circular hole in the middle having a radius larger than the material outlet radius. The vibrating screen mesh 14 has three layers, with the mesh size decreasing from top to bottom. A strip support frame is installed on the outside of the vibrating screen frame 13, and the strip support frame is connected to the vibrating motor 16. An electric push rod 15 is also connected to the bottom of the vibrating screen frame 13. Both the vibrating motor 16 and the electric push rod 15 are electrically connected to the controller 50, and the controller 50 controls their switching.

[0039] Furthermore, the lower layer of the main body 1 is a vacuum-sealed environment. The vacuum system 21 and the refrigeration system 20 are located behind the supercritical carbon dioxide extraction device on the outside of the main body 1. The vacuum system 21 is connected to the side of the lower layer through a pipe. The hatch connection adopts a standard CF flange interface, which is clamped with a clamp. The condenser trap 22 in the lower layer is equipped with a condenser coil. The condenser coil is sealed to the bulkhead by welding and connected to the refrigeration system 20. An automatic switch valve is installed below the material outlet of the lower layer and connected to a magnetic sealing joint 18. The magnetic sealing joint 18 is equipped with a ring magnet and a sealing ring. One end of the magnetic sealing joint 18 is connected to a food-grade hose. The food-grade hose is connected to a stainless steel fixed pipeline. The stainless steel fixed pipeline is connected to the perilla powder silo 27 via a rotary valve 24. Valves are installed on both the pipelines before and after the rotary valve 24. The two-position five-way solenoid valve 33, the control component of the weighing sensor 31 and the pneumatic ball valve 32, is electrically connected to the controller 50. It controls the powder to enter the material weighing tank 29 from the perilla powder silo 27 for weighing. After the weighing reaches the standard, the pneumatic ball valve 32 is opened, allowing the powder to fall vertically into the extraction vessel 39 by gravity, thereby realizing the rapid and sealed feeding of perilla leaf powder into the extraction vessel 39. The paddle agitator 40, ultrasonic generator 42, high-precision constant temperature water bath 44, and flat plate sealed filter 45 in the extraction vessel 39 are electrically connected to the controller 50. The controller 50 controls their switching and parameter settings.

[0040] Working principle of the invention: When preparing perilla leaf extract, the user first opens the sealing cap 5 and evenly places fresh perilla leaves into the material tank 8. The sealing cap 5 is then reset to ensure the cavity is sealed. The stirring motor 2 is started, driving the propeller 4 to evenly agitate the material. Infrared processing parameters are set, and the infrared lamps 7 and 6 are activated to uniformly pre-treat the perilla leaves, removing some moisture and activating the active ingredients. After infrared treatment, the system automatically enters the cooling stage, waiting for the material temperature to drop to room temperature. The sealing gate valve 10 and high-vacuum gate valve 11 are opened sequentially, and the material enters the vibrating screen frame 13 along the first material outlet 9. Then, the sealing gate valve 10 and high-vacuum gate valve 11 are closed, forming a sealed freeze-drying environment in the lower layer of the device. The refrigeration system 20 and vacuum system 21 are activated, rapidly reducing the cavity temperature and establishing a high-vacuum environment. Moisture in the perilla leaves sublimates directly under freezing conditions and is captured by the condenser trap 22. After the freeze-drying process is completed, the system enters standby mode. The vibrating motor 16 is started, and the high-frequency vibration causes the freeze-dried perilla leaves to collide and break on the screen. Powder that reaches the predetermined particle size passes through the vibrating screen 14 and falls into the collection area at the bottom of the vibrating screen frame 13; coarse material that does not meet the requirements continues to be crushed. After crushing, the electric push rod 15 is precisely started, pushing the vibrating screen frame 13 to tilt towards the second material outlet 17, ensuring that the powder in the collection area is fully concentrated near the second material outlet 17. Subsequently, the magnetic sealing joint 18 at the second material outlet 17 automatically completes docking and locking, forming a sealed conveying channel. The second material outlet 17 and the rotary valve 24 are opened in sequence, and the oil-free vacuum pump 30 is started. Under the action of negative pressure airflow, the perilla powder is safely and efficiently transported through the sealed pipeline to the perilla powder silo 27 of the eutectic solvent extraction device.

[0041] After material conveying is completed, the conveying system valves are closed. The eutectic solvent extraction system is started: the eutectic solvent in the DES storage tank 34 is conveyed to the extraction vessel 39 via the flow meter 35. Simultaneously, the material weighing tank 29 at the bottom of the perilla powder silo 27 completes the quantitative weighing of the perilla powder through the weighing sensor 31. Then, the air-operated ball valve 32 is opened, and the perilla powder enters the extraction vessel 39. During the extraction process, the ultrasonic generator 42 and the paddle agitator 40 equipped in the extraction vessel 39 are started to enhance the mass transfer process. After extraction, the mixture enters the flat plate sealed filter 45, and solid-liquid separation is carried out by the inflatable diaphragm press plate under the action of compressed air. The crude perilla extract enters the extract storage tank 46 through the liquid outlet 47, and the residue is discharged into the residue collection box 48 through the residue outlet 49. Finally, the crude extract is purified using D101 macroporous resin to obtain perilla leaf extract. This completes the process of preparing perilla leaf extract using the above-described apparatus.

[0042] Example 1 This embodiment provides a method for preparing perilla leaf extract, including the following steps: Step 1: Take fresh, unrotten perilla leaves, wash and drain them; open the sealing lid on top of the extraction tank, evenly spread the washed fresh perilla leaves in the material tank, then replace the sealing lid to ensure the chamber is sealed. Start the stirring motor to drive the propeller to agitate the perilla leaves, ensuring they are heated evenly. Set the infrared pretreatment temperature to 50℃ and the pretreatment time to 120 seconds; simultaneously start the infrared lamps and the ring infrared lamp to perform infrared pretreatment on the perilla leaves, effectively removing some moisture and activating the active ingredients.

[0043] Step Two: After infrared treatment, the system automatically enters the cooling stage. Once the material temperature drops to room temperature, the sealed gate valve and the high-vacuum gate valve open sequentially, allowing the perilla leaves to fall into the lower vibrating screen frame along the material outlet. The valves then close, creating a sealed freeze-drying environment in the lower layer. The vacuum freeze-drying conditions are set as follows: vacuum degree 50 Pa, cold trap temperature -60 ℃, freezing temperature -40 ℃. The refrigeration and vacuum systems are activated, rapidly reducing the chamber temperature and establishing high vacuum conditions. The moisture in the perilla leaves sublimates directly under freezing conditions and is captured by the condenser.

[0044] Step 3: After the freeze-drying process is completed, the system enters standby mode. At this time, the vibration motor is started, and the freeze-dried perilla leaves are crushed by collision on the screen through high-frequency vibration. Powder that reaches the predetermined particle size falls through the screen into the bottom collection area, while coarse material that does not meet the requirements continues to be crushed. After crushing is completed, the electric push rod pushes the vibrating screen frame to tilt towards the material outlet side, so that the powder is concentrated near the outlet.

[0045] Step 4: The magnetic sealing joint at the material outlet automatically engages and locks, forming a sealed conveying channel. The material outlet and rotary valve are then opened sequentially, and the vacuum pump is started. Under negative pressure airflow, the perilla powder is safely conveyed through the sealed pipeline to the powder hopper of the eutectic solvent extraction system.

[0046] Step 5: After the transfer is completed, close the valve. The eutectic solvent in the DES storage tank is precisely delivered to the extraction vessel via a flow meter. Simultaneously, the material weighing tank at the bottom of the powder silo uses a high-precision weighing sensor to quantitatively weigh the perilla powder. The air-operated ball valve is then opened to feed the powder into the extraction vessel. The extraction conditions are: ultrasonic power 295W, ultrasonic time 29 minutes, extraction temperature 51℃, and a material-to-liquid ratio of 1:20 (g / mL). During the extraction process, the ultrasonic-assisted system operates synchronously with the stirrer to enhance mass transfer.

[0047] Step Six: After extraction, the mixture enters a flat-plate sealed filter to achieve solid-liquid separation. The crude perilla extract flows into the extract storage tank through the liquid outlet, while the residue is discharged into the collection tank through the residue outlet. Finally, the crude extract is purified using D101 macroporous resin to obtain perilla leaf extract.

[0048] Determination of polyphenol content in perilla leaf extract: The polyphenol content in perilla leaf extract was determined using the Folin-Ciocalteu method. 1.00 mL of perilla leaf extract was accurately pipetted into a 25 mL graduated test tube, diluted to 10 mL with distilled water, and 0.5 mL of Folin-Ciocalteu reagent was added. After mixing, 10 mL of 7.5% sodium carbonate solution was added, mixed again, and the tube was placed in a 25°C water bath in the dark for 60 min. Then, distilled water was added to bring the volume to 25 mL. A blank control was used, and the absorbance was measured at 750 nm. A standard curve was constructed using different concentrations of gallic acid. The total phenol content was expressed as gallic acid equivalent (GAE) mg / perilla leaf dry weight (g).

[0049] Determination of rosmarinic acid content in perilla leaf extract: The ferrous sulfate colorimetric method was used for determination. Rosmarinic acid was used as the standard substance, with the concentration of rosmarinic acid on the x-axis and the absorbance value A on the y-axis, to obtain the standard curve equation: y = 0.0003x + 0.0001 (R² = 0.9994), which was used to calculate the rosmarinic acid content.

[0050] Antioxidant activity assay of perilla leaf extract: Using VC as a positive control, the absorbance values ​​AC of the control group and AS of the sample group were measured at a wavelength of 517 nm. The DPPH free radical scavenging rate was calculated using the following formula: DPPH free radical scavenging rate (%) = (AC - AS) / AC × 100%.

[0051] GC-MS component analysis of perilla leaf extract: The perilla leaf extract was dissolved in petroleum ether, and its components were detected by gas chromatography-mass spectrometry (GC-MS).

[0052] GC analysis conditions: The chromatographic column was a Shimadzu SH-Rtx-5 MS quartz capillary column, weakly polar, 30 m × 0.25 mm × 0.25 μm (length × inner diameter × film thickness); temperature program: initial temperature 60℃, hold for 1 min, increase to 180℃ at 3℃·min⁻¹, hold for 1 min, then increase to 260℃ at 10℃·min⁻¹; injection temperature 260℃; carrier gas helium flow rate 1.20 mL·min⁻¹; column inlet pressure: 87 kPa (constant pressure mode); injection volume 0.2 μL; split ratio 20:1; detector was a flame ionization detector (FID) at 270℃.

[0053] MS analysis conditions: ionization mode EI, electron energy 70 eV, multiplier tube voltage 1.1 kV; ion source temperature 200℃; interface temperature 270℃; quadrupole temperature 150℃; nucleus-to-mass ratio scan range 26–500 m·z⁻¹; acquisition mode full scan.

[0054] The software's built-in spectral library search program and the NIST20-1 mass spectrometry database were used to compare the mass spectrometry fragmentation maps and standard spectra of each component. The chemical components were identified by combining mass spectrometry fragmentation patterns and manual spectral analysis. The relative content of each chemical component was determined by peak area normalization. This study only explored the components with a relative mass content greater than 0.5%.

[0055] Example 2: Optimization of Infrared Preprocessing Conditions This embodiment aims to determine the optimal process conditions for the infrared pretreatment unit in the integrated device of the present invention.

[0056] Step 1: Same as Step 1 in Example 1; Step 2: Using a two-factor, multi-level experimental design, place the samples of each experimental group in the infrared preprocessing unit of the device of this invention and process them according to the parameters in the table below.

[0057] Table 1. Experimental Grouping of Infrared Pretreatment

[0058] Steps 3-6: Same as steps 3-6 in Example 1; Step 7: Collect the final extracts from each group, determine their perillaldehyde and rosmarinic acid contents, and determine their antioxidant activity (expressed as IC50) using the DPPH method. 50 (Value representation).

[0059] Experimental results: Table 2 shows the contents of perillaldehyde and rosmarinic acid, and the antioxidant activity of DPPH in the perilla leaf extract measured in Example 2.

[0060] Table 2. Extraction yield, total phenol content, rosmarinic acid and perillaldehyde content, and DPPH antioxidant activity of perilla leaf extract.

[0061]

[0062] The results show that infrared pretreatment conditions significantly affect the extraction efficiency. Using the device of this invention to extract perilla leaf extract, when the pretreatment conditions were 50℃ for 120 seconds (P50-T120), the total phenolic content (46.32 mg GAE / g) and rosmarinic acid content (23.58 mg / g) of the obtained perilla leaf extract were significantly increased. The content of the key volatile component perillaldehyde reached the highest level of 13.76 mg / g, and the antioxidant activity was also the strongest (IC50). 50The concentration was 58.42 μg / mL, indicating the best overall quality. This superior performance is attributed to the synergistic mechanism of infrared pretreatment: its thermal effect not only rapidly removes moisture but also potentially alters the cell wall structure, increasing cell wall permeability. This structural change significantly enhances the sublimation efficiency of subsequent vacuum freeze-drying and creates favorable conditions for the penetration of eutectic solvents. This mechanism was validated in comparative examples—Comparative Example 2 (hot air + DES) suffered from component degradation due to high temperature, and Comparative Example 3 (freeze-drying + ethanol) had significantly lower active ingredient content than this invention due to insufficient solvent efficiency. This fully demonstrates that the combination of infrared-freeze-drying and ultrasonic-DES extraction produces a synergistic effect that is not simply additive. Therefore, P50-T120 was determined to be the optimal process parameters.

[0063] Example 3: Optimization of Ultrasonic-Assisted Extraction Conditions for Low-Euclidean Solvents This embodiment aims to determine the optimal process conditions for the ultrasonic-assisted eutectic solvent extraction unit in the integrated device of the present invention.

[0064] Steps 1-4: Same as Steps 1-4 in Example 1; Step 5: After the transfer is completed, close the valve. The eutectic solvent in the DES storage tank is precisely delivered to the extraction vessel via a flow meter. Simultaneously, the material weighing tank at the bottom of the powder silo uses a high-precision weighing sensor to quantitatively weigh the perilla powder. The air-operated ball valve is opened to send the powder into the extraction vessel. The ultrasonic power is fixed at 295W, the ultrasonic time at 29 minutes, and the extraction temperature at 51℃. The material-to-liquid ratio (g / mL) was tested at 1:5, 1:10, 1:15, 1:20, and 1:25.

[0065] Step 5: Same as Step 6 in Example 1; Step 7: Collect the final extracts from each group, determine the contents of perillaldehyde and rosmarinic acid, and determine the antioxidant activity (expressed as IC50 value) using the DPPH method.

[0066] Experimental results showed that as the material-to-liquid ratio increased from 1:5 to 1:20, the extraction rates of total phenol content, rosmarinic acid, and perillaldehyde all increased, reaching a peak at 1:20. The total phenol content was expected to reach 45.94 mg GAE / g, the rosmarinic acid content approximately 23.36 mg / g, and the perillaldehyde content approximately 13.41 mg / g. DPPH free radical scavenging ability was the strongest (IC50). 50The concentration was approximately 58.07 μg / mL, indicating that the solvent fully wetted the material under these conditions, resulting in high mass transfer efficiency and facilitating the dissolution of active ingredients. Increasing the material-to-liquid ratio to 1:25 did not significantly improve any indicators and even slightly decreased them. This may be because excessive solvent diluted the concentration of active ingredients per unit volume, weakened the ultrasonic cavitation effect, and reduced energy efficiency. Therefore, a material-to-liquid ratio of 1:20 was determined to be the optimal process condition for the ultrasonic-assisted eutectic solvent extraction stage. At this ratio, extraction efficiency is ensured while also considering economy and process feasibility, resulting in the best overall extraction effect.

[0067] Comparative Example 1: Hot air drying-solvent extraction of perilla leaf extract The steps are the same as in Example 1, Step 1; Step 2: The perilla leaves were dried with hot air at 55 ℃ to constant weight. The dried sample was then pulverized, passed through a 60-mesh sieve, sealed, and stored at 4 ℃ for later use.

[0068] Step 3: Weigh an appropriate amount of the dried perilla leaf powder and place it in a round-bottom flask. Add 10 times the amount of 70% ethanol solution. Extract twice by reflux at 80 °C, 1.5 hours each time, and combine the two extracts.

[0069] Step 4: The combined extracts were purified using D101 macroporous resin to obtain perilla leaf extract. The contents of perillaldehyde and rosmarinic acid were determined, and the antioxidant activity (expressed as IC50) was measured using the DPPH method. 50 (Value representation).

[0070] The results showed that the overall quality of the perilla leaf extract prepared by the traditional hot air drying-solvent reflux extraction method was significantly lower than that of the extract prepared by the integrated equipment of this invention. Firstly, the total phenolic content of the hot air-solvent extract (24.87 mg GAE / g) was significantly lower than that of the extract of this invention (46.32 mg GAE / g), indicating poor selectivity and the introduction of a large amount of inactive impurities. Secondly, the key active components suffered significant losses, with the contents of the heat-sensitive component rosmarinic acid (10.56 mg / g) and the volatile component perillaldehyde (5.33 mg / g) both significantly lower than those of the extract of this invention (23.58 mg / g; 13.76 mg / g), demonstrating that the prolonged high-temperature treatment in the traditional process led to significant degradation and volatilization of these components. Simultaneously, the antioxidant activity of the perilla leaf extract obtained by hot air drying-solvent extraction was significantly weakened, and its DPPH free radical scavenging capacity (IC50) was significantly reduced. 50 The concentration of 112.49 μg / mL is significantly lower than that of the extract of this invention (IC). 50 : 58.42 μg / mL).

[0071] Comparative Example 2: Hot air drying-low eutectic solvent extraction of perilla leaf extract The steps are the same as in Example 1, Step 1; Step 2: The perilla leaves were dried with hot air at 55℃ to constant weight. The dried sample was then pulverized, passed through a 60-mesh sieve, sealed, and stored at 4℃ for later use.

[0072] Step 3: Take the hot-air dried perilla leaf powder and extract it using a low-eutectic solvent. The extraction conditions are: DES solvent (choline chloride: 1,3-butanediol = 1:2 (molar ratio), water content 50%), extraction temperature 51℃, solid-liquid ratio 1:20 (g / mL). Centrifuge the obtained extract, collect the supernatant, and purify the crude extract using D101 macroporous resin to obtain perilla leaf extract. Determine the contents of perillaldehyde and rosmarinic acid, and determine the antioxidant activity (expressed as IC50) using the DPPH method. 50 (Value representation).

[0073] The results showed that the overall quality of the perilla leaf extract obtained by hot air drying-low eutectic solvent extraction was lower than that of the extract prepared by the integrated process of this invention. The total phenolic content (41.25 mg GAE / g) and rosmarinic acid content (19.84 mg / g) of the obtained perilla leaf extract decreased by approximately 10.94% and 15.86%, respectively, while the loss of the volatile component perillaldehyde was particularly severe, with its content (9.27 mg / g) decreasing by 32.63%. Furthermore, its DPPH free radical scavenging activity (IC50) was significantly reduced. 50 The concentration of 68.93 μg / mL in the perilla extract was also lower than that of the perilla extract prepared under optimal conditions using an integrated device (IC50). 50 : 58.42 μg / mL).

[0074] Comparative Example 3: Vacuum freeze-drying-solvent extraction of perilla leaf extract The steps are the same as in Example 1, Step 1; Step 2: Vacuum freeze-dry the above-mentioned perilla leaves to constant weight. The vacuum freeze-drying conditions are set as follows: vacuum degree 50 Pa, cold trap temperature -60 ℃, freezing temperature -40 ℃. Step 3: Weigh an appropriate amount of the dried perilla leaf powder and place it in a round-bottom flask. Add 10 times the amount of 70% ethanol solution. Extract twice by reflux at 80 °C, 1.5 hours each time, and combine the two extracts.

[0075] Step 4: The combined extracts were purified using D101 macroporous resin to obtain perilla leaf extract. The contents of perillaldehyde and rosmarinic acid were determined, and the antioxidant activity (expressed as IC50) was measured using the DPPH method. 50 (Value representation).

[0076] The results showed that the extract obtained by vacuum freeze-drying-solvent extraction was superior to the traditional hot air drying method in terms of retention of active ingredients, but still inferior to the integrated process of the device of this invention. The total phenol content (36.44 mg GAE / g), rosmarinic acid content (20.52 mg / g), and perillaldehyde content (11.35 mg / g) of the obtained extract were only 78.67%, 87.02%, and 82.49% of the product of this invention (46.32 mg GAE / g; 23.58 mg / g; 13.76 mg / g), respectively; correspondingly, its DPPH free radical scavenging activity (IC50) was also significantly lower. 50 The concentration of 66.8 μg / mL is also weaker than that of the present invention (IC). 50 : 58.42 μg / mL).

[0077] The above results fully demonstrate that traditional processes, due to their inability to avoid high-temperature, long-term, and aerobic operating environments, severely restrict the content of active ingredients and the overall quality of the final product. In contrast, this invention employs integrated equipment, combining infrared pretreatment, vacuum freeze-drying, and ultrasound-assisted eutectic solvent extraction technologies to successfully achieve low-temperature, high-efficiency, and highly selective extraction. While ensuring a high yield, it maximizes the preservation of heat-sensitive and volatile active ingredients, ultimately yielding perilla leaf extract with higher purity of active ingredients, stronger biological activity, and superior quality.

[0078] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. An integrated apparatus for preparing perilla leaf extract, characterized in that, Includes a main body (1), the interior of which is divided into an upper layer and a lower layer by a high-vacuum gate valve (11); The upper layer is provided with a material tank (8) for holding materials and a propeller (4) extending downward into the material tank (8). The bottom of the material tank (8) is provided with a first material outlet (9). A sealing gate valve (10) is installed at the first material outlet (9). The inner wall of the upper layer of the main body (1) is also provided with infrared lamp tubes (7) arranged around the material tank (8). The lower layer is provided with a vibrating screen frame (13), and the vibrating screen frame (13) is equipped with a vibrating screen mesh (14). The bottom layer of the vibrating screen mesh (14) is provided with a second material outlet (17), and the second material outlet (17) is connected to a magnetic sealing joint (18). An electric push rod (15) and a vibration motor (16) are connected below the vibrating screen frame (13). A condensation trap (22) is also installed at the bottom of the vibrating screen frame (13), and a water outlet (23) is provided at the bottom of the condensation trap (22). The second material outlet (17) is connected in sequence to the powder conveying and metering system and the flat plate sealed filter (45) through a sealed pipe (19); the powder conveying and metering system includes a perilla powder silo (27), a material weighing trough (29) and a weighing sensor (31) connected in sequence; the material weighing trough (29) is flexibly connected to the high-precision weighing sensor (31), and its bottom outlet is directly connected to the feed port of the extraction vessel (39) through an air-operated ball valve (32); the air-operated ball valve (32) is connected to the air compressor (37) of the pulse backflushing system through a two-position five-way solenoid valve (33); The lower layer is also equipped with a vacuum system (21), and the condenser (22) is connected to the refrigeration system (20) through a pipe.

2. The equipment according to claim 1, characterized in that, The second material outlet (17) is connected to the perilla powder silo (27) through a sealed pipe (19); a rotary valve (24) is provided on the sealed pipe (19); a set of filters (26) is provided on the top of the perilla powder silo (27); the vacuum perilla powder silo (27) is connected to the oil-free vacuum pump (30) through a vacuum pipe; at the same time, a compressed air pipe is also connected to the clean side of the filter (26); a pulse solenoid valve (25) is provided on the compressed air pipe; the compressed air pipe is connected to the air compressor (37) to form a pulse backflushing system; The flat-plate sealed filter (45) includes a filter plate assembly, a hydraulic closure system, and an inflatable diaphragm pressing plate located in the filter plate assembly; the feed inlet of the flat-plate sealed filter (45) is connected to the bottom outlet of the ultrasonic extraction vessel; the liquid outlet (47) of the flat-plate sealed filter (45) is connected to the extract storage tank (46); the residue outlet (49) of the flat-plate sealed filter (45) is connected to the residue collection box (48); the flat-plate sealed filter (45) is also equipped with a compressed gas interface, which is connected to an air compressor (37) through a pipeline to provide pressing power to the inflatable diaphragm.

3. The equipment according to claim 2, characterized in that, The connection between the main body (1) and the stirring motor (2) is a fixed connection, and the propeller (4) is symmetrically distributed along the vertical center line of the stirring motor (2); the front surface of the main body (1) is provided with a controller (50), which is electrically connected to the stirring motor (2), and the controller (50) controls the rotation of the stirring motor (2).

4. The equipment according to claim 3, characterized in that, The infrared lamps (7) are symmetrically distributed on the four walls inside the main body. The controller (50) is electrically connected to the infrared lamps (7) and controls the irradiation time and irradiation power of the infrared lamps (7).

5. The equipment according to claim 4, characterized in that, The material trough (8) is provided with round holes around its perimeter, so that the infrared light emitted by the infrared lamp tube (7) can be evenly irradiated onto the material.

6. The equipment according to claim 5, characterized in that, The sealed gate valve (10) is electrically connected to the controller (50), and the controller (50) controls the opening and closing of the sealed gate valve (10).

7. The equipment according to claim 6, characterized in that, The main body (1) is provided with a high vacuum gate valve (11) in the middle. The high vacuum gate valve (11) is equipped with a sealing ring. The valve body is made of 304 stainless steel, the valve plate is made of stainless steel, and elastic sealing rings are inlaid on both sides of the gate. The sealing rings are made of perfluoroether rubber. The high vacuum gate valve (11) is electrically connected to the controller (50). The controller (50) controls the high vacuum gate valve (11) to start or close the valve.

8. The equipment according to claim 7, characterized in that, The vibrating screen frame (13) is equipped with a dust cover (12). The dust cover (12) has a porous structure with a circular hole in the middle with a radius larger than that of the material outlet (9). The vibrating screen mesh (14) has three layers, and the mesh size of each layer decreases from top to bottom. The vibrating screen frame (13) is equipped with a strip support frame on the outside. The strip support frame is connected to the vibrating motor (16). The bottom of the vibrating screen frame (13) is also connected to an electric push rod (15). The vibrating motor (16) and the electric push rod (15) are both electrically connected to the controller (50). The controller (50) controls the switching of the two.

9. The equipment according to claim 8, characterized in that, The lower layer of the main body (1) is a vacuum-sealed environment. The vacuum system (21) and the refrigeration system (20) are located behind the supercritical carbon dioxide extraction device (21) on the outside of the main body (1). The vacuum system is connected to the side of the lower layer through a pipe. The hatch connection adopts a standard CF flange interface. The standard CF flange interface is clamped with a clamp. The condenser coil is installed in the condenser trap (22) of the lower layer. The condenser coil is sealed to the cabin wall by welding and connected to the refrigeration system (20). An automatic switch valve is installed below the material outlet (17) of the lower layer and connected to a magnetic sealing joint (18). The magnetic sealing joint (18) is equipped with a ring magnet and a sealing ring. One end of the magnetic sealing joint (18) is connected to a food-grade hose. The food-grade hose is connected to a stainless steel fixed pipeline. The stainless steel fixed pipeline is connected to the perilla powder silo (27) via a rotary valve (24). Valves are provided on the pipelines before and after the rotary valve (24). The two-position five-way solenoid valve (33) of the control component of the weighing sensor (31) and the air-operated ball valve (32) is electrically connected to the controller (50) to control the powder to enter the material weighing tank (29) from the perilla powder silo (27) for weighing. After the weighing reaches the standard, the air-operated ball valve (32) is opened so that the powder falls vertically into the extraction vessel (39) by gravity, thereby realizing the feeding of perilla leaf powder into the extraction vessel (39). The paddle agitator (40), ultrasonic generator (42), high-precision constant temperature water bath (44), and flat plate sealed filter (45) in the extraction vessel (39) are electrically connected to the controller (50), and the controller (50) controls their switches and parameter settings.

10. A method for preparing perilla leaf extract, characterized in that, Using the integrated equipment according to claim 9 includes the following steps: Step 1: Take fresh, unrotten perilla leaves, wash and drain them; open the sealing cover on top of the extraction tank, spread the washed fresh perilla leaves evenly in the material tank, and then replace the sealing cover to ensure the cavity is sealed; start the stirring motor, drive the propeller to turn the perilla leaves over so that they are heated evenly, and start the infrared lamp and the ring infrared lamp at the same time to perform infrared pretreatment on the perilla leaves, effectively removing some moisture and activating the active ingredients; Step 2: After the infrared processing is completed, the system automatically enters the cooling stage. Once the material temperature drops to room temperature, the sealed gate valve and the high-vacuum gate valve open in sequence, and the perilla leaves fall into the lower vibrating screen frame along the material outlet; then the valve closes, and a sealed freeze-drying environment is formed in the lower layer; the refrigeration system and the vacuum system are started, which quickly reduce the cavity temperature and establish high vacuum conditions, and the moisture in the perilla leaves sublimates directly in the frozen state and is captured by the condenser trap. Step 3: After the freeze-drying process is completed, the system enters standby mode. At this time, the vibration motor is started, and the freeze-dried perilla leaves are crushed by collision on the screen through high-frequency vibration; the powder that reaches the predetermined particle size falls through the screen into the bottom collection area, and the coarse material that does not meet the requirements continues to be crushed; after the crushing is completed, the electric push rod pushes the vibrating screen frame to tilt towards the material outlet side, so that the powder is concentrated near the outlet. Step 4: The magnetic sealing joint at the material outlet automatically engages and locks, forming a sealed conveying channel; the material outlet and rotary valve are opened in sequence, the vacuum pump is started, and under the action of negative pressure airflow, the perilla powder is safely conveyed through the sealed pipeline to the powder silo of the eutectic solvent extraction system; Step 5: After the conveying is completed, close the valve. The eutectic solvent in the DES storage tank is accurately conveyed to the extraction vessel through the flow meter. At the same time, the material weighing tank at the bottom of the powder silo completes the quantitative weighing of the perilla powder through the high-precision weighing sensor. The air-operated ball valve is opened to send the powder into the extraction vessel. During the extraction process, the ultrasonic auxiliary system and the stirrer run synchronously to enhance the mass transfer effect. Step 6: After extraction, the mixture enters a flat plate sealed filter to achieve solid-liquid separation. The crude perilla extract enters the extract storage tank through the liquid outlet, while the residue is discharged into the collection box through the residue outlet. Finally, the crude extract is purified using D101 macroporous resin to obtain perilla leaf extract.

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