Fresh processing technology of poria cocos
Patent Information
- Application Number
- CN202611276208.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-21
- Publication Date
- 2026-10-09
AI Technical Summary
[0005]本发明提供了一种茯苓趁鲜加工工艺，通过非热灭酶与射频脉冲压差干燥的协同作用，在维持茯苓刚性骨架的前提下实现微孔化快速脱水，解决传统工艺中多糖热降解严重、干燥耗时长及组织致密复水性差的技术问题
[0024]本发明通过介质阻挡放电低温等离子体非热灭酶与射频-脉冲压差耦合真空干燥的协同，将保留细胞壁刚性骨架作为后续闪蒸破壁的力学基质，不仅阻断酶促褐变途径并避免传统高温灭酶引起的多糖热降解与淀粉糊化，更利用压降瞬间水分的剧烈闪蒸在茯苓内部构建均匀连通的三维微孔结构，该微孔结构又作为水分气相迁移的通道降低射频解析的毛细管阻力，从而将整体干燥时间缩短，最终提高所得茯苓多糖保留率，以及提高复水膨胀比，实现茯苓趁鲜加工的高效能、高保真与优异品质。
Smart Images
Figure CN122874498A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of traditional Chinese medicine processing technology, and in particular to a processing method for fresh Poria cocos. Background Technology
[0002] Poria cocos is an important medicinal and edible fungus with diuretic, spleen-strengthening, and mind-calming effects. Traditional processing of Poria cocos is cumbersome, requiring "sweating," repeated soaking, slicing, and air-drying or sun-drying. This process is not only time-consuming and prone to mold growth, but repeated soaking also leads to the significant loss of water-soluble active ingredients such as polysaccharides. In recent years, the industry has begun to promote a "fresh processing" technique for Poria cocos, where fresh Poria cocos is directly peeled, sliced, enzyme-inactivated, and dried after harvesting.
[0003] However, existing processing techniques for fresh poria cocos still have the following significant drawbacks: First, fresh poria cocos is highly susceptible to enzymatic browning after being cut. Traditionally, high-temperature steam or boiling water is used to inactivate the enzymes, which leads to the collapse of the cell walls on the surface of the poria cocos, severe gelatinization of starch, and thermal degradation of active ingredients such as poria cocos polysaccharides. Second, existing drying processes mostly use hot air drying. Because the poria cocos tissue shrinks and becomes dense after heat inactivation of enzymes, the resistance to the migration of internal water to the outside is extremely high, which easily produces a "dry outside and wet inside" crusting effect, resulting in extremely long drying time and easy reddish-brown discoloration in the center. Finally, the dense keratinized structure results in extremely low porosity of the final product, making it difficult for water to penetrate during clinical decoction, and the extraction rate and rehydration of effective ingredients are both poor.
[0004] Therefore, there is an urgent need for a new processing technology for fresh Poria cocos that can avoid heat damage, increase porosity, and preserve authenticity efficiently. Summary of the Invention
[0005] This invention provides a fresh processing technology for Poria cocos, which achieves rapid dehydration through microporousization by combining non-thermal enzyme inactivation with radio frequency pulse pressure difference drying, while maintaining the rigid framework of Poria cocos. This solves the technical problems of severe polysaccharide thermal degradation, long drying time, and poor tissue density and rehydration in traditional processes.
[0006] This invention provides a fresh processing method for Poria cocos, which includes sequentially washing, peeling, slicing, enzyme inactivation, and drying the fresh Poria cocos, specifically including the following steps:
[0007] (1) Wash the fresh Poria cocos with water jet to remove mud and bacteria from the surface of the fresh Poria cocos.
[0008] (2) The fresh Poria cocos after cleaning was subjected to targeted radiation thermal shock using mid-wave infrared light, which caused the bonding layer between the outer skin and the inner sclerotium of the fresh Poria cocos to denature and break due to heat. The outer skin was then removed by mechanical friction.
[0009] (3) Cut the peeled fresh Poria cocos into Poria cocos cubes;
[0010] (4) The poria cocos diced is transported to a dielectric barrier discharge low-temperature plasma treatment chamber, where active oxygen and high-energy electrons excited by a high-voltage electric field are used to perform non-thermal enzyme inactivation treatment on the poria cocos diced.
[0011] (5) The enzyme-inactivated Poria cocos cubes are subjected to radio frequency and pulse pressure difference coupled vacuum drying, which is carried out in sequence through radio frequency vacuum preheating stage, pulse pressure difference flash evaporation pore-forming stage and radio frequency constant temperature low pressure desorption stage until the moisture content of the Poria cocos cubes reaches the preset value.
[0012] Further, in step (1), the fresh Poria cocos is cleaned by ultrasonic-coupled micro-nano bubble water jet; wherein the frequency of the ultrasonic wave is 28~40kHz, and the micro-nano bubble particle size in the micro-nano bubble water jet is 50~200nm.
[0013] Furthermore, in step (2), the emission peak of the mid-wave infrared radiation is 2.2~3.0 μm, and the radiation intensity is 4.5~5.5 kW / m. 2 .
[0014] Furthermore, in step (2), the irradiation time of the targeted radiation thermal shock is 15~22s, so that the local temperature of the outer skin of fresh Poria cocos rises to above 85℃, while the temperature of the internal sclerotium remains below 35℃.
[0015] Furthermore, in step (3), the peeled fresh Poria cocos is cut into cubic blocks with a side length of 5mm to 10mm.
[0016] Furthermore, in step (4), the operating conditions of the dielectric barrier discharge cryogenic plasma treatment chamber include:
[0017] A mixture of argon and oxygen with a volume ratio of 93:7 is introduced as the working gas;
[0018] The applied high-frequency AC voltage is 35~45kV, and the discharge frequency is 8~10kHz;
[0019] The processing temperature is 15~35℃, and the processing time is 80~100s.
[0020] Furthermore, in the radio frequency vacuum preheating stage of step (5), the radio frequency generator is turned on under an absolute pressure of 20~30kPa in the drying chamber, and the water molecules inside the Poria cocos are heated by friction through radio frequency polarization until the center temperature of the Poria cocos rises to 58~62℃; wherein, the working frequency of the radio frequency generator is 27.12MHz.
[0021] Furthermore, in the pulse pressure difference flash evaporation pore-forming stage of step (5), when the center temperature of Poria cocos reaches 58~62℃, the radio frequency field is cut off and the vacuum pressure relief valve is opened within 1.5s, so that the absolute pressure in the drying chamber drops sharply to 2~3kPa, so that the superheated water inside Poria cocos will flash evaporate, thereby forming a uniform three-dimensional microporous structure.
[0022] Furthermore, in the radio frequency isothermal low-pressure desorption stage of step (5), the absolute pressure inside the drying chamber is maintained at 2~3kPa and the radio frequency field is restarted, the plate voltage is controlled at 1~2kV, and the temperature of Poria cocos is maintained at 45~50℃ for desorption and drying until the moisture content is ≤9%.
[0023] The beneficial effects of this invention are as follows:
[0024] This invention utilizes the synergy of dielectric barrier discharge low-temperature plasma non-thermal enzyme inactivation and radio frequency-pulse pressure difference coupled vacuum drying. It preserves the rigid framework of the cell wall as the mechanical matrix for subsequent flash evaporation and cell wall disruption. This not only blocks the enzymatic browning pathway and avoids the thermal degradation of polysaccharides and starch gelatinization caused by traditional high-temperature enzyme inactivation, but also utilizes the intense flash evaporation of water during the pressure drop to construct a uniform and interconnected three-dimensional microporous structure inside Poria cocos. This microporous structure also serves as a channel for water vapor-phase migration, reducing the capillary resistance of radio frequency desorption, thereby shortening the overall drying time. Ultimately, this improves the polysaccharide retention rate of the obtained Poria cocos and increases the rehydration expansion ratio, achieving high efficiency, high fidelity, and excellent quality in fresh Poria cocos processing. Attached Figure Description
[0025] Figure 1 This is a schematic flowchart of the fresh processing method for Poria cocos according to the present invention.
[0026] Figure 2 This is a temperature-pressure-time curve of the radio frequency-pulse differential pressure coupling vacuum drying stage in Embodiment 1 of the present invention.
[0027] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0028] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0029] Example 1
[0030] This embodiment provides a process for processing Poria cocos while it is still fresh, such as... Figure 1 As shown, it includes the following steps:
[0031] (1) Fresh Poria cocos was washed with water jet.
[0032] Freshly harvested Poria cocos with a moisture content of 55% was placed in a washing tank and cleaned using ultrasonic-coupled micro-nano bubble water jets. The ultrasonic frequency was set to 35kHz, and the micro-nano bubble particles in the water jets were concentrated at a size of approximately 100nm. The micro-jet generated by the asymmetric collapse of ultrasonic cavitation bubbles at the micropores on the irregular surface of the Poria cocos precisely removed attached mud and bacteria without damaging the integrity of the fresh Poria cocos's outer skin.
[0033] (2) Mid-wave infrared transient thermal shock peeling
[0034] The cleaned fresh Poria cocos was transported to an infrared tunnel for targeted radiative thermal shock. Mid-wave infrared radiation with an emission peak of 2.6 μm was selected, and the radiation intensity was set to 5.0 kW / m². 2 The irradiation time is 18 seconds.
[0035] The dark brown outer skin and the 1-1.5 mm thick cork layer of Poria cocos exhibit strong characteristic absorption of infrared radiation in this wavelength range. The local temperature rapidly rises to 88℃ within 18 seconds, while the temperature of the internal white sclerotium remains around 30℃. This significant thermal stress gradient causes the gelatinous layer at the junction of the epidermis and the internal sclerotium to denature and rupture instantaneously. Subsequently, the fresh Poria cocos enters a roller brush machine, where the outer skin is easily removed through mechanical friction, reducing the peeling loss rate to 2.5%.
[0036] (3) Cut while fresh
[0037] Using a three-dimensional dicing machine, the peeled fresh Poria cocos flesh is diced into cubic blocks with a side length of 8mm.
[0038] (4) DBD low-temperature plasma targeted non-thermal inactivation enzyme
[0039] The poria cocos cubes were transported in a single layer with a thickness of 8 mm into a dielectric barrier discharge (DBD) cryogenic plasma treatment chamber. An argon-oxygen mixture with a volume ratio of 93:7 was introduced as the working gas, and the flow rate of the mixed gas was controlled at 2.0 L / min. A high-frequency AC voltage of 40 kV was applied, the discharge frequency was 9 kHz, the treatment environment temperature was maintained at 25 °C, and the treatment was continued for 90 seconds.
[0040] The plasma excited by the high-voltage electric field is rich in reactive oxygen species (ROS) and high-energy electrons. It can penetrate the surface of Poria cocos and target the active sites of polyphenol oxidase (PPO) and peroxidase (POD), causing irreversible unfolding of the protein spatial conformation and achieving cold inactivation of the enzymes. This step, while blocking the enzymatic browning pathway, maintains the integrity of the Poria cocos cell wall skeleton and the crystal structure of the internal linear polysaccharides, without producing obvious starch gelatinization, thus providing the structural basis and mechanical matrix conditions for subsequent differential pore formation.
[0041] (5) Radio frequency and pulsed differential pressure coupled vacuum drying
[0042] The enzyme-inactivated Poria cocos pieces were placed in the gap between the radio frequency electrodes (the electrode spacing was set to 120 mm). Figure 2 As shown, the coupled drying process is carried out in three stages, specifically:
[0043] Radio frequency vacuum preheating stage: Under an absolute pressure of 25 kPa inside the drying chamber, the radio frequency generator (operating frequency of 27.12 MHz, electrode voltage of 3 kV) is turned on. The high-frequency alternating electric field is used to polarize the water molecules inside the Poria cocos cube and generate heat through high-frequency friction, achieving synchronous heating of the material inside and out without gradient, until the center temperature of the Poria cocos cube reaches 60℃.
[0044] Pulse pressure difference flash evaporation pore-forming stage: When the center temperature reaches 60℃, the radio frequency field is instantly cut off, and the vacuum pressure relief valve is quickly opened within 1.0s, causing the absolute pressure in the drying chamber to drop sharply to 2.5kPa. At the moment of pressure drop, the superheated water inside the Poria cocos diced undergoes violent flash evaporation. Because the non-thermal enzyme inactivation in step (4) maintains the necessary rigidity of the Poria cocos cell wall, when the pressure difference between the internal vapor pressure and the external vacuum pressure is greater than the critical yield stress of the cell wall, the expanding water vapor breaks through the cell wall matrix outward, forming a three-dimensional microporous structure with certain connectivity and uniform distribution inside the Poria cocos diced.
[0045] Radiofrequency isothermal low-pressure desorption stage: Maintain the absolute pressure inside the drying chamber at 2.5 kPa, restart the radiofrequency field and reduce the electrode voltage to 1.5 kV, maintaining the temperature of Poria cocos cubes at 48℃ for isothermal low-pressure desorption drying. The microporous structure formed by the aforementioned flash evaporation creates an effective channel for moisture vapor phase migration, avoiding increased capillary resistance and end-corner arcing in the later stages of radiofrequency drying. Continue processing until the moisture content of Poria cocos cubes drops to 8%, at which point drying is complete.
[0046] Example 2
[0047] The process steps in this embodiment are basically the same as those in Embodiment 1, except that lower limit values are used for the relevant process parameters, specifically:
[0048] In step (1), the ultrasonic frequency is 28 kHz and the micro-nano bubble particle size is 50 nm.
[0049] In step (2), the mid-wave infrared emission peak is 2.2 μm, and the radiation intensity is 4.5 kW / m. 2 The irradiation time is 22 seconds, which raises the local temperature of the outer skin to 85°C, while the temperature of the internal sclerotia remains below 35°C (e.g., 32°C).
[0050] In step (3), the Poria cocos cubes are cut into cubic blocks with a side length of 5mm.
[0051] In step (4), the paving thickness is 5 mm, the mixed gas flow rate is 1.5 L / min, the applied high-frequency AC voltage is 35 kV, the discharge frequency is 8 kHz, the processing ambient temperature is 20 ℃, and the processing time is 100 s.
[0052] In step (5), the electrode spacing is 100 mm; the absolute pressure during the preheating stage is 30 kPa, and the center temperature is heated to 58°C; during the flash evaporation stage, the vacuum relief valve is opened within 1.5 s (or 1.2 s) to make the absolute pressure drop sharply to 3 kPa; during the desorption stage, the electrode voltage is maintained at 1 kV, and the temperature is 45°C for drying until the moisture content reaches 9%.
[0053] Example 3
[0054] The process steps in this embodiment are basically the same as those in Embodiment 1, except that upper limits are used for the relevant process parameters, specifically:
[0055] In step (1), the ultrasonic frequency is 40kHz and the micro-nano bubble particle size is 200nm.
[0056] In step (2), the mid-wave infrared emission peak is 3.0 μm, and the radiation intensity is 5.5 kW / m. 2 The irradiation time is 15 seconds, which raises the local temperature of the outer skin to above 85℃ (e.g., 89℃), while the internal sclerotium temperature is kept below 35℃.
[0057] In step (3), the Poria cocos cubes are cut into cubic blocks with a side length of 10mm.
[0058] In step (4), the paving thickness is 10 mm, the mixed gas flow rate is 2.5 L / min, the applied high-frequency AC voltage is 45 kV, the discharge frequency is 10 kHz, the processing ambient temperature is 35 ℃, and the processing time is 80 s.
[0059] In step (5), the electrode spacing is 140 mm; the absolute pressure during the preheating stage is 20 kPa, and the center temperature is heated to 62 °C; during the flash evaporation stage, the absolute pressure drops sharply to 2 kPa within 1.5 s; during the desorption stage, the electrode voltage is maintained at 2 kV, and the temperature is 50 °C for drying until the moisture content reaches 7%.
[0060] To verify the technical effect of the present invention, namely the synergistic effect between each step, parallel tests were conducted on the same batch of fresh Poria cocos (cut into 8mm cubic blocks), setting up Example 1 to Example 3 groups and three comparative groups.
[0061] Comparative Example 1 (Test of the effect of conventional heat-induced enzyme inactivation): Step (4) in Example 1 of this invention was replaced with “100°C hot steam boiling for 5 minutes to inactivate enzyme”, and the remaining steps (including parameters such as water washing, cutting and radio frequency pulse differential drying) were exactly the same as in Example 1.
[0062] Comparative Example 2 (Single Drying Mode Effect Test): The complete steps (1) to (4) of Example 1 were used, but in step (5) the drying process was replaced with the conventional "60°C constant temperature hot air drying".
[0063] Comparative Example 3 (Traditional High-End Freeze-Drying Comparison): Traditional high-temperature steam scalding was used to inactivate enzymes, and the drying step was replaced with vacuum freeze-drying (pre-freezing at -40℃, followed by gradual temperature increase and vacuum desorption).
[0064] The core indicator detection data are shown in Table 1:
[0065] Table 1. Comparison of Measured Performance Parameters of Various Embodiments and Comparative Examples of the Present Invention
[0066] Grouping Total drying time (h) Poria cocos polysaccharide retention rate (%) Microporosity (%) Rehydration expansion ratio Appearance and color (L* value) Central browning rate (%) Example 1 3.5 94.2 48.5 3.85 91.2 (Pure White) 0 Example 2 4.1 92.8 45.2 3.72 90.5 (Pure White) 0 Example 3 3.2 93.6 47.1 3.78 90.8 (Pure White) 0 Comparative Example 1 4.8 82.5 15.2 1.95 83.4 (Slightly yellow) 4 Comparative Example 2 14.5 88.3 8.5 1.62 87.5 (Surface is whitish) 12 (Reddish center) Comparative Example 3 36.0 84.1 51.0 3.90 89.1 (Pure White) 0
[0067] Test method description:
[0068] The retention rate of Poria cocos polysaccharides was determined using the phenol-sulfuric acid method (referencing the General Chapter of Part IV of the Chinese Pharmacopoeia), and the content was compared with the polysaccharide content of fresh product on a dry basis. Microporosity was determined using mercury intrusion porosimetry (MIP) to detect the pore size distribution and cumulative porosity of the samples. The rehydration swelling ratio was determined by placing a constant-weight sample in a 100℃ boiling water bath for 30 min, and the volume expansion factor after water absorption was calculated using a formula. Appearance and color (L* value) were measured using a spectrophotometer under a D65 light source (lightness index; the closer L* is to 100, the higher the whiteness).
[0069] Based on the above experimental data, as shown in Table 1, regardless of whether the preferred parameters (Example 1) or the lower limit (Example 2) and upper limit (Example 3) of the process parameters are used, the process of the present invention can control the drying time within 4.1 hours, the retention rate of Poria cocos polysaccharides is stable at over 92.8%, and the browning is effectively inhibited, proving that the entire parameter range of this application can achieve consistent technical effects.
[0070] Comparative Example 1 used traditional high-temperature steam inactivation of enzymes, resulting in severe gelatinization of the outer starch layer of Poria cocos and collapse of the cell walls to form a dense cuticle. Even with subsequent strong radio frequency-pulse pressure differential operation, the internal water could not effectively break through the tough gelatinized layer, resulting in hindered "flash evaporation puffing" and a microporosity of only 15.2%, with a significantly reduced rehydration expansion ratio. In contrast, Example 1 achieved a microporosity of 48.5%, demonstrating that the non-thermal enzyme inactivation in step (4) of this invention maintained the integrity of the skeleton, and formed a synergistic mechanism with the pressure differential flash evaporation and pore-forming process in step (5).
[0071] Comparative Example 2 lacked the pulse flash pore-forming step, and the simple hot air drying caused the Poria cocos tissue to shrink, preventing timely migration of internal moisture and creating a "dry outside, moist inside" shell effect. This not only resulted in a drying time of 14.5 hours, but also caused a 12% non-enzymatic browning rate in the central part due to high moisture retention. In contrast, Example 1 of the present invention completed the dehydration process in a shorter time (3.5 hours), effectively maintaining the initial quality of the sample.
[0072] Compared to freeze-drying technology with higher physical quality evaluation in the industry (Comparative Example 3), this invention reduces the processes of water washing and sweating and hot steam boiling, which improves the retention rate of Poria cocos polysaccharides. At the same time, the radio frequency-pulse coupled drying of this invention significantly shortens the dehydration time from 36 hours of freeze-drying to less than 3.5 hours, which has good application value in fresh processing at industrial production sites.
[0073] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.
[0074] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A processing method for fresh Poria cocos, comprising sequentially washing, peeling, slicing, inactivating enzymes, and drying the fresh Poria cocos, characterized in that, Specifically, the following steps are included: (1) Wash the fresh Poria cocos with water jet to remove mud and bacteria from the surface of the fresh Poria cocos. (2) The fresh Poria cocos after cleaning was subjected to targeted radiation thermal shock using mid-wave infrared light, which caused the bonding layer between the outer skin and the inner sclerotium of the fresh Poria cocos to denature and break due to heat. The outer skin was then removed by mechanical friction. (3) Cut the peeled fresh Poria cocos into Poria cocos cubes; (4) The poria cocos diced is transported to a dielectric barrier discharge low-temperature plasma treatment chamber, where active oxygen and high-energy electrons excited by a high-voltage electric field are used to perform non-thermal enzyme inactivation treatment on the poria cocos diced. (5) The enzyme-inactivated Poria cocos cubes are subjected to radio frequency and pulse pressure difference coupled vacuum drying, which is carried out in sequence through radio frequency vacuum preheating stage, pulse pressure difference flash evaporation pore-forming stage and radio frequency constant temperature low pressure desorption stage until the moisture content of the Poria cocos cubes reaches the preset value.
2. The fresh processing method for Poria cocos according to claim 1, characterized in that, In step (1), fresh Poria cocos is cleaned using ultrasonic-coupled micro-nano bubble water jet; wherein the frequency of the ultrasonic wave is 28~40kHz, and the micro-nano bubble particle size in the micro-nano bubble water jet is 50~200nm.
3. The fresh processing method for Poria cocos according to claim 1, characterized in that, In step (2), the emission peak of the mid-wave infrared radiation is 2.2~3.0 μm, and the radiation intensity is 4.5~5.5 kW / m. 2 .
4. The fresh processing method for Poria cocos according to claim 3, characterized in that, In step (2), the irradiation time of the targeted radiation thermal shock is 15~22s, which raises the local temperature of the outer skin of fresh Poria cocos to above 85℃, while the temperature of the internal sclerotium remains below 35℃.
5. The fresh processing method for Poria cocos according to claim 1, characterized in that, In step (3), the peeled fresh Poria cocos is cut into cubic blocks with a side length of 5mm to 10mm.
6. The fresh processing method for Poria cocos according to claim 1, characterized in that, In step (4), the operating conditions of the dielectric barrier discharge cryogenic plasma treatment chamber include: A mixture of argon and oxygen with a volume ratio of 93:7 is introduced as the working gas; The applied high-frequency AC voltage is 35~45kV, and the discharge frequency is 8~10kHz; The processing temperature is 15~35℃, and the processing time is 80~100s.
7. The fresh processing method for Poria cocos according to claim 1, characterized in that, In the radio frequency vacuum preheating stage of step (5), the radio frequency generator is turned on under an absolute pressure of 20~30kPa in the drying chamber. The water molecules inside the Poria cocos are heated by friction through radio frequency polarization until the center temperature of the Poria cocos rises to 58~62℃. The working frequency of the radio frequency generator is 27.12MHz.
8. The fresh processing method for Poria cocos according to claim 7, characterized in that, In the pulse pressure difference flash evaporation pore-forming stage of step (5), when the center temperature of Poria cocos reaches 58~62℃, the radio frequency field is cut off and the vacuum pressure relief valve is opened within 1.5s, so that the absolute pressure in the drying chamber drops sharply to 2~3kPa, so that the superheated water inside Poria cocos will flash evaporate, thereby forming a uniform three-dimensional microporous structure.
9. The fresh processing method for Poria cocos according to claim 8, characterized in that, In the radio frequency isothermal low-pressure desorption stage of step (5), the absolute pressure in the drying chamber is maintained at 2~3kPa and the radio frequency field is restarted. The plate voltage is controlled at 1~2kV, and the temperature of Poria cocos is maintained at 45~50℃ for desorption and drying until the moisture content is ≤9%.