A method for stir-frying Chinese medicinal herbs

Abstract

This invention discloses a method for stir-frying Chinese medicinal materials, comprising the following steps: processing and preparation of the medicinal materials to be stir-fried; preheating stage; brittleness stage; shaping stage: stopping heating and switching to cold air to cool the outer shell of the medicinal materials to be stir-fried, thereby locking the shell into a brittle and tough state and preventing the shell and kernel from sticking together again due to residual heat or moisture absorption; in the later stage of the shaping stage, the control system automatically extends the cold air running time or increases the air volume in stages according to a preset program, guiding part of the cold air flow to directionally scour the inner wall of the stir-frying chamber, the stirring paddle and the bottom heating surface, thereby actively and forcibly cooling the equipment body, so that the temperature of the metal surface of the chamber drops below 60°C before batch switching, significantly reducing the influence of thermal inertia, providing a uniform and controllable initial heating environment for the next batch of medicinal materials, and eliminating the risk of local overheating or cracking.

Description

Technical Field

[0001] This invention specifically relates to a method for stir-frying Chinese medicinal herbs. Background Technology

[0002] Among the many Chinese medicinal herbs that require roasting, there is a special category whose medicinal part is only the kernel of the seed or fruit, while the outer layer is covered by a hard, dense, non-medicinal shell or seed coat. Typical examples include Quisqualis indica, Ginkgo biloba, Alpinia oxyphylla, and Amomum tsao-ko. These herbs must have their outer shell removed before clinical use, using only the pure kernel. Traditional processing typically involves "roasting first, then removing the shell": the herbs with shells are placed in a pot and roasted over low or medium heat until the outer shell darkens in color, becomes brittle, and partially cracks. Then, the kernel is separated from the outer shell by manual methods such as tapping, rubbing, and winnowing. Although this method has been used for thousands of years, in the context of modern industrialization, standardization, and intelligent development of Chinese medicine, it has revealed a series of insurmountable technical bottlenecks. First, the outer shell of these medicinal materials is mostly lignified or cellulose-based, which rapidly dehydrates, shrinks, and becomes brittle upon heating. The kernel, rich in protein, starch, or oil, has poor thermal conductivity and its internal temperature rises later. It expands upon heating but contracts upon cooling due to moisture loss and temperature drop. This asynchronous response to thermal expansion and contraction easily leads to a tight adhesion between the kernel and shell during cooling, making clean separation difficult even under external force. Often, strong knocking or repeated rubbing is required, resulting in kernel breakage, loss of active ingredients, and impurity residue.

[0003] Secondly, after completing one batch of processing, the traditional intermittent herbal frying pan accumulates a large amount of heat, with the surface temperature often exceeding 150°C. If the next batch of cold herbs is added directly, it will cause intense initial heating, localized overheating, or even cracking. If the pan is allowed to cool down naturally, the equipment's turnover efficiency will be severely reduced.

[0004] Even more seriously, if the freshly stir-fried medicinal materials are not removed in time or if there is still residual heat in the pot after removal, the residual materials or subsequent batches are prone to "over-stirring with residual heat", which manifests as darkening of color, the production of a burnt smell, and degradation of effective ingredients, seriously affecting the uniformity and safety of the quality of the medicinal materials. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for stir-frying Chinese medicinal herbs to solve the problems existing in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is a method for stir-frying Chinese herbal medicine slices, comprising the following steps: Step S1, Processing and preparation of medicinal materials to be stir-fried: Cleaning and selecting medicinal materials with shells; Step S2, Preheating stage: The medicinal materials to be stir-fried are sent into the stir-frying chamber, and hot air is introduced into the stir-frying chamber to evenly remove the surface and shallow moisture of the medicinal materials. Step S3, embrittlement stage: Increase the temperature of the hot air to dehydrate and embrittle the outer shell of the medicinal material to be roasted while keeping the kernel intact, so that the shell is loose and brittle. Step S4, Shaping Stage: Stop heating and switch to cold air to cool down the outer shell of the medicinal material to be roasted, so as to lock the shell into a brittle and tough state and prevent the shell and kernel from sticking together again due to residual heat or moisture absorption.

[0007] Preferably, in step S2, the temperature of the incoming airflow is between 60 degrees Celsius and 90 degrees Celsius, and the wind speed is between 0.5 m / s and 1.2 m / s; in step S3, the temperature of the incoming airflow is between 110 degrees Celsius and 150 degrees Celsius, and the wind speed is between 0.4 m / s and 0.7 m / s; in step S4, the temperature of the incoming airflow is between 15 degrees Celsius and 25 degrees Celsius, and the wind speed is between 1.5 m / s and 2 m / s.

[0008] Preferably, in step S4, cold air is continuously supplied until the temperature of the medicinal materials to be roasted drops below 40 degrees Celsius.

[0009] Preferably, in steps S2, S3, and S4, the airflow is introduced from the bottom and / or side of the frying chamber to achieve uniform disturbance and heat exchange of the medicinal materials to be fried; when the medicinal materials to be fried are small-particle-size and lightweight, the hot air introduced adopts a lateral air supply method with bottom air supply as the main method; when the medicinal materials to be fried are large-particle-size and heavy, the hot air introduced adopts a bottom air supply method with side air supply as the main method.

[0010] Preferably, in steps S2 and S3, the hot air temperature is increased in stages; in step S2, a full exhaust mode is used, and the proportion of fresh air in the incoming airflow is 100%; during the transition from step S2 to step S3 and during step S3, return air is gradually introduced, so that the proportion of fresh air gradually decreases from 100% to 30% to 40%, and the proportion of return air increases accordingly to 60% to 70%.

[0011] Furthermore, the frying chamber has a fresh air circuit and an exhaust air circuit. A humidity sensor is installed in the exhaust air circuit to monitor the relative humidity of the exhaust airflow in real time. During the transition from step S2 to step S3 and during step S3, the mixing ratio of fresh air and return air treated by dust removal and dehumidification is dynamically adjusted according to the feedback signal of the humidity sensor.

[0012] Furthermore, the fresh air circuit includes a hot air circuit and a cold air circuit. The hot air circuit is used to supply hot air during the preheating and embrittlement stages, and the cold air circuit is used to supply cold air during the shaping stage. The exhaust circuit includes a direct exhaust circuit and a recirculation circuit. The direct exhaust circuit is used to directly exhaust the exhaust airflow during the preheating and shaping stages, and the recirculation circuit is used to exhaust a portion of the reused exhaust airflow during the embrittlement stage.

[0013] Furthermore, a heat exchanger is provided between the circulation loop and the hot air loop. During the brittle stage, the airflow discharged from the frying chamber first flows through the hot side of the heat exchanger to preheat the fresh airflow. After processing, part of it is returned to the hot air loop as return air.

[0014] Preferably, the air volume in the preheating stage and the air volume in the shaping stage are both greater than the air volume in the embrittlement stage.

[0015] Preferably, the medicinal material to be stir-fried can be at least one selected from ginkgo, quisqualis indica, alpinia oxyphylla, tsaoko, torreya, and euphorbia lathyris; after cleaning the medicinal material with shells, its moisture content is controlled to be 8% to 12%.

[0016] The main technical effects of this invention are reflected in the following aspects: This approach employs a three-pronged strategy: physical isolation of hot and cold air paths, active chamber cooling, and closed continuous production. This simultaneously addresses two major industry challenges: excessive heat buildup in materials and interference from equipment heat accumulation. The strategy achieves a dual improvement in process stability and production efficiency through a triple-synergistic mechanism: First, the hot air circuit (used in preheating stage S2 and embrittlement stage S3) and the cold air circuit (used in shaping stage S4) are completely independent in terms of piping structure and airflow path. The cold airflow does not pass through a high-temperature heat exchanger or share an exhaust channel, effectively preventing secondary heating by equipment waste heat. This ensures that the temperature of the cooling airflow entering the roasting chamber is stably maintained at 15–25℃, thereby efficiently and quickly removing sensible heat from the material and precisely locking in the ideal state of "brittle shell and tough kernel," preventing secondary adhesion of the kernel and shell due to slow cooling. Second, in the later stages of the shaping stage, the control system automatically extends the cold air running time or increases the airflow in stages according to a preset program, guiding... Part of the cold airflow is directed to scour the inner wall of the frying chamber, the stirring paddle, and the bottom heating surface, actively and forcibly cooling the equipment body. This reduces the temperature of the metal surface of the chamber to below 60°C before batch switching, significantly reducing the effects of thermal inertia and providing a uniform and controllable initial heating environment for the next batch of medicinal materials, eliminating the risk of local overheating or explosion. Thirdly, the entire frying and cooling process is completed continuously within the same sealed chamber, with the material never exposed to the external environment. This not only avoids dust, moisture, and microbial contamination, meeting GMP cleanliness requirements, but also eliminates the heat loss, energy waste, and process interruption problems caused by the traditional process of "frying, removing from the pot, spreading out to cool, and then adding more material," greatly improving equipment turnover efficiency and batch-to-batch consistency. Through the organic integration of the above three mechanisms, this invention fundamentally breaks through the bottleneck of quality fluctuations caused by the coupling of equipment heat storage and material waste heat in traditional intermittent frying pans, providing reliable technical support for the intelligent, continuous, and standardized production of Chinese herbal medicine slices.

[0017] Traditional roasting uses a single heating temperature, which causes the outer shell to rapidly dehydrate and become brittle, while the kernel remains in a high-temperature and high-humidity state due to delayed heat conduction. Upon cooling, the kernel shrinks and adheres tightly to the already brittle inner shell, forming a difficult-to-separate adhesive interface. This invention uses a low-temperature, high-volume airflow at 60–90℃ during the preheating stage to uniformly remove surface and shallow moisture, preventing a sudden increase in internal vapor pressure. During the brittleness stage, the temperature is raised to 110–150℃ to selectively dehydrate and brittle the lignin in the outer shell, while the kernel maintains its structural integrity due to the slow-release heating in the early stages. During the shaping stage, a dry, cold airflow at 15–25℃ is immediately switched to rapidly cool the material to below 40℃, "freezing" the kernel-shell interface within the optimal window of "shell brittle, kernel not shrunken," thus locking in a mutually beneficial separation state.

[0018] Different particle sizes and densities of shelled medicinal materials exhibit significantly different movement characteristics in airflow: small, lightweight materials (such as Torreya grandis) are easily lifted and aggregated by vertical airflow, while large, heavy materials (such as Amomum tsao-ko) tend to sink to the bottom and experience uneven heating. This invention provides lifting force through bottom main airflow and enhances lateral tumbling with auxiliary side airflow, forming a three-dimensional disturbance field; furthermore, it intelligently switches the dominant airflow direction according to the type of medicinal material—using side airflow as the main force to prevent small, lightweight materials from flying away, and bottom airflow as the main force to enhance suspension for large, heavy materials. This adaptive airflow design significantly improves the uniformity of heat exchange, enhances the consistency of shell embrittlement, and overcomes the bottleneck of traditional drum-type herb roasting machines' "one-size-fits-all" airflow, which is difficult to handle multiple varieties. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the present invention; Figure 2 for Figure 1 Airflow pattern during the intermediate embrittlement stage. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so as to make the technical solution of the present invention easier to understand and master. In the embodiments, it should be understood that the terms "middle," "upper," "lower," "top," "right side," "left end," "above," "back," "center," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, unless otherwise specified in this specific embodiment, the connection or fixing method between components can be achieved by bolt fixing, pin fixing, or pin connection commonly used in the prior art, etc., and therefore will not be described in detail in this embodiment.

[0021] The method for stir-frying Chinese medicinal herbs provided by this invention is mainly applied to the stir-frying and shaping process of shelled Chinese medicinal materials (such as ginkgo, Quisqualis indica, Alpinia oxyphylla, and Amomum villosum kernels) whose medicinal part is the kernel and which need to be shelled. However, it is not limited to this and can also be applied to the drying, embrittlement and cooling processes of other Chinese medicinal materials or natural products with similar structural characteristics (i.e., the outer shell is dense and not medicinal, and the inner kernel is the effective part) or the same heat-sensitive treatment requirements.

[0022] Furthermore, as is common knowledge in this field, the high-efficiency filters (dust removal), dehumidifiers (dehumidification), heat pipe heat exchangers, humidity sensors, PLC control systems, and bottom / side air supply structures mentioned above are all conventional components in existing food / pharmaceutical drying equipment. Their working principles, selection criteria, and integration methods have been fully disclosed in relevant technical manuals and engineering practices. The above content constitutes technical knowledge generally known to those skilled in the art; therefore, its specific principles and internal structures will not be elaborated upon further.

[0023] Example 1 See Figure 1 , one The method for stir-frying Chinese medicinal herbs includes the following steps: Step S1, Processing and preparation of medicinal materials to be stir-fried: Clean the medicinal materials with shells; the medicinal materials to be stir-fried can be at least one selected from ginkgo, quisqualis indica, alpinia oxyphylla, tsaoko, torreya, and euphorbia lathyris; after cleaning the medicinal materials with shells, control their moisture content to be 8% to 12%.

[0024] Step S2, Preheating Stage: The medicinal materials to be stir-fried are sent into the stir-frying chamber, and hot air is introduced into the stir-frying chamber to evenly remove surface and shallow moisture from the medicinal materials; the stir-frying chamber has a fresh air circuit and an exhaust air circuit, and a humidity sensor is installed in the exhaust air circuit to monitor the relative humidity of the exhaust airflow in real time; the temperature of the introduced airflow is between 60 degrees Celsius and 90 degrees Celsius, and the wind speed is between 0.5 meters per second and 1.2 meters per second; Step S3, Embrittling Stage: Increase the temperature of the hot air to dehydrate and embrittle the outer shell of the medicinal material to be roasted while keeping the kernel intact, so that the shell is loose and brittle; the temperature of the airflow is between 110 degrees Celsius and 150 degrees Celsius, and the wind speed is between 0.4 meters per second and 0.7 meters per second. Step S4, Shaping Stage: Stop heating and switch to cold air to cool down the outer shell of the medicinal material to be roasted, so as to lock the shell into a brittle state and prevent the shell and kernel from sticking together again due to residual heat or moisture absorption; the temperature of the airflow is between 15 degrees Celsius and 25 degrees Celsius, and the wind speed is between 1.5 meters per second and 2 meters per second; the cold air is continuously supplied until the temperature of the medicinal material to be roasted drops below 40 degrees Celsius.

[0025] In steps S2, S3, and S4, the airflow is introduced from the bottom and / or side of the frying chamber to achieve uniform disturbance and heat exchange of the medicinal materials to be fried. When the medicinal materials to be fried are small-particle-size and lightweight, the introduced hot air adopts a side-flowing method with bottom-flowing as a supplement; when the medicinal materials to be fried are large-particle-size and heavy, the introduced hot air adopts a bottom-flowing method with side-flowing as a supplement. In steps S2 and S3, the hot air temperature adopts a staged heating method; in step S2, a full exhaust mode is adopted, and the proportion of fresh air in the introduced airflow is 100%; see [link to relevant documentation]. Figure 2 During the transition from step S2 to step S3 and during step S3, return air is gradually introduced, causing the proportion of fresh air to gradually decrease from 100% to 30% to 40%, while the proportion of return air increases accordingly to 60% to 70%. Based on the feedback signal from the humidity sensor, the mixing ratio of fresh air and return air treated with dust removal and dehumidification is dynamically adjusted. The fresh air circuit includes a hot air circuit and a cold air circuit. The hot air circuit supplies hot air for the preheating and embrittlement stages, and the cold air circuit supplies cold air for the shaping stage. The exhaust circuit includes a direct exhaust circuit and a recirculation circuit. The direct exhaust circuit directly discharges the exhaust airflow from the preheating and shaping stages, while the recirculation circuit discharges a portion of the reused exhaust airflow from the embrittlement stage. A heat exchanger is installed between the recirculation circuit and the hot air circuit. During the embrittlement stage, the airflow discharged from the roasting chamber first flows through the hot side of the heat exchanger to preheat the fresh airflow, and a portion of it is then returned to the hot air circuit as return air. The air volume during the preheating stage and the air volume during the shaping stage are both greater than the air volume during the embrittlement stage.

[0026] Example 2 This embodiment uses ginkgo (ginkgo) as a typical example to explain in detail the specific implementation process of the traditional Chinese medicine decoction piece stir-frying method of the present invention and its significant improvements and innovations compared with traditional processes.

[0027] First, in step S1, ginkgo nuts in their shells that meet the standards of the Chinese Pharmacopoeia are selected and cleaned by vibrating sieve, air separation, and manual sorting to remove impurities, shriveled nuts, and damaged nuts. Then, the cleaned ginkgo nuts are placed in a constant temperature and humidity environment for 24 hours to equilibrate, controlling their moisture content to 9.5% (within the preferred range of 8%–12%). This moisture content control is crucial to ensure that the kernels do not burst or burn during the subsequent roasting process, preventing bursting due to excessive moisture causing a sudden increase in steam pressure, or premature carbonization of the shell due to insufficient moisture.

[0028] In step S2, the preheating stage, the ginkgo nuts are placed into the sealed intelligent roasting chamber. The hot air circuit is activated, introducing clean hot air at 75℃, a wind speed of 0.8 m / s, and a relative humidity of 35% for 8 minutes. The airflow is evenly delivered from the bottom of the chamber, supplemented by lateral turbulence, causing the ginkgo nuts to suspend and tumble within the drum, achieving gentle and even removal of surface and shallow moisture. This stage employs a 100% fresh air exhaust mode to ensure timely removal of moisture and prevent humidity accumulation within the chamber. Compared to the traditional "dry-burning" heating method of pan-frying, this stage, through low-temperature, high-volume preheating, effectively alleviates stress concentration caused by the difference in thermal conductivity between the kernel and the shell, fundamentally inhibiting the tendency for kernel and shell to stick together during the subsequent cooling stage.

[0029] The system then proceeds to step S3, the embrittlement stage. It automatically raises the hot air temperature to 130°C, reduces the wind speed to 0.6 m / s, and initiates a phased heating program (increasing the temperature by 10°C every 2 minutes) to prevent uneven shell cracking caused by sudden temperature changes. Simultaneously, a humidity sensor in the exhaust circuit monitors the exhaust air moisture content in real time. When the relative humidity stabilizes at 38%, the PLC control system gradually opens the return air valve, introducing the return air, processed by a high-efficiency filter (F8 grade) and dehumidifier, into the mixing chamber. This smoothly transitions the fresh air ratio from 100% to 35%, with the return air accounting for 65%. At the same time, the high-temperature exhaust airflow passes through the hot side of the heat pipe heat exchanger before being discharged, transferring residual heat to the cold side of the fresh air, raising the fresh air inlet temperature by approximately 25°C and significantly reducing the main heater's energy consumption. Under these conditions, the ginkgo shell lignin is fully dehydrated and embrittled, exhibiting a uniform light yellow color and crumbling easily upon pressure. Meanwhile, the internal kernel, due to delayed and controlled heating, remains intact, plump, and free of scorch marks.

[0030] Finally, in step S4, the shaping stage, heating is immediately stopped, and the process switches to an independent cold air circuit. Dry, cold air at 20℃, relative humidity ≤30%, and a velocity of 1.8 m / s is introduced, with the airflow continuing from both the bottom and sides to ensure that large-diameter ginkgo nuts are fully agitated. The cold air continues for 4 minutes until the infrared thermometer indicates the overall material temperature has dropped below 38℃. This rapid cooling process quickly "freezes" the shells into the ideal state of brittle shells and firm kernels, completely preventing secondary adhesion of the shells and kernels caused by residual heat conduction or environmental moisture absorption. It is worth noting that the cold air stage uses a direct exhaust mode; the exhaust air does not pass through a heat exchanger or reuse system, avoiding accidental heating of the cold air by the high-temperature heat exchanger and ensuring cooling efficiency. The entire roasting process is completed continuously within a single, sealed chamber, eliminating the need for material transfer and preventing external dust and moisture contamination.

[0031] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A method for stir-frying Chinese medicinal herbs, characterized in that: Includes the following steps: Step S1, Processing and preparation of medicinal materials to be stir-fried: Cleaning and selecting medicinal materials with shells; Step S2, Preheating stage: The medicinal materials to be stir-fried are sent into the stir-frying chamber, and hot air is introduced into the stir-frying chamber to evenly remove the surface and shallow moisture of the medicinal materials. Step S3, embrittlement stage: Increase the temperature of the hot air to dehydrate and embrittle the outer shell of the medicinal material to be roasted while keeping the kernel intact, so that the shell is loose and brittle. Step S4, Shaping Stage: Stop heating and switch to cold air to cool down the outer shell of the medicinal material to be fried, so as to lock the shell in a brittle and tough state and prevent the shell and kernel from sticking together again due to residual heat or moisture absorption. In steps S2, S3, and S4, airflow is introduced from the bottom and / or side of the frying chamber to achieve uniform disturbance and heat exchange of the medicinal materials to be fried. When the medicinal materials to be fried are small-particle-size and lightweight, the hot air is supplied mainly by side air supply and supplemented by bottom air supply. When the medicinal materials to be fried are large-particle-size and heavy, the hot air is supplied mainly by bottom air supply and supplemented by side air supply. In steps S2 and S3, the hot air temperature is increased in stages. In step S2, a full exhaust ventilation mode is adopted, and the proportion of fresh air in the incoming airflow is 100%. During the transition from step S2 to step S3 and during step S3, return air is gradually introduced, so that the proportion of fresh air gradually decreases from 100% to 30% to 40%, and the proportion of return air increases accordingly to 60% to 70%. The frying chamber has a fresh air circuit and an exhaust air circuit. A humidity sensor is installed in the exhaust air circuit to monitor the relative humidity of the exhaust airflow in real time. During the transition from step S2 to step S3 and during step S3, the mixing ratio of fresh air and return air treated by dust removal and dehumidification is dynamically adjusted according to the feedback signal of the humidity sensor. The fresh air circuit includes a hot air circuit and a cold air circuit. The hot air circuit is used to supply hot air for the preheating and embrittlement stages, and the cold air circuit is used to supply cold air for the shaping stage. The exhaust circuit includes a direct exhaust circuit and a recirculation circuit. The direct exhaust circuit is used to directly exhaust the exhaust airflow during the preheating and shaping stages, and the recirculation circuit is used to exhaust a portion of the reused exhaust airflow during the embrittlement stage.

2. The method for stir-frying Chinese medicinal herbs as described in claim 1, characterized in that: In step S2, the temperature of the incoming airflow is between 60 degrees Celsius and 90 degrees Celsius, and the wind speed is between 0.5 meters per second and 1.2 meters per second. In step S3, the temperature of the incoming airflow is between 110 degrees Celsius and 150 degrees Celsius, and the wind speed is between 0.4 meters per second and 0.7 meters per second. In step S4, the temperature of the incoming airflow is between 15 and 25 degrees Celsius, and the wind speed is between 1.5 and 2 meters per second.

3. The method for stir-frying Chinese medicinal herbs as described in claim 1 or 2, characterized in that: In step S4, cold air is continuously supplied until the temperature of the medicinal materials to be roasted drops below 40 degrees Celsius.

4. The method for stir-frying Chinese medicinal herbs as described in claim 1, characterized in that: A heat exchanger is installed between the circulation loop and the hot air loop. During the brittle stage, the airflow discharged from the frying chamber first flows through the hot side of the heat exchanger to preheat the fresh airflow, and after processing, part of it is returned to the hot air circuit as return air.

5. The method for stir-frying Chinese medicinal herbs as described in claim 1 or 2, characterized in that: The air volume during the preheating stage and the air volume during the shaping stage are both greater than the air volume during the embrittlement stage.

6. The method for stir-frying Chinese medicinal herbs as described in claim 1 or 2, characterized in that: The medicinal materials to be processed can be at least one selected from ginkgo, quisqualis indica, alpinia oxyphylla, tsaoko, torreya, and euphorbia lathyris; after cleaning the medicinal materials with shells, their moisture content is controlled to be 8% to 12%.

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