A pretreatment method for detecting food source allergen gluten protein

Abstract

The application discloses a pretreatment method for detecting food source allergen gluten protein, and belongs to the field of food detection pretreatment. Food sample particles are mixed with deionized water wetting liquid and input into a pressure-bearing metal cavity. A variable lead screw is used to apply mechanical shearing force. Carbon dioxide is pumped in synchronously and a supercritical fluid phase state is maintained. Carbon dioxide molecules are caused to penetrate into a covalent cross-linking network and induce matrix microswelling. When the material is pushed to the discharge end, physical swelling stress generated by transient volume expansion of deeply penetrated carbon dioxide is used to realize nondestructive wall breaking of a covalent cross-linking network of a deep-processed food, release food source allergen gluten protein, and at the same time, solid-gas mixed fluid dynamic impact is used to spray an extraction buffer coaxially, a local low-temperature atomization capture environment is constructed, and under the trigger logic of pressure and torque coupling, the release timing of wall breaking energy is precisely controlled, so that food source allergen gluten protein is efficiently physically captured and dissolved in situ on the premise that the spatial structure integrity of an antigen epitope is maintained.

Description

Technical Field

[0001] This invention relates to the field of food pretreatment technology, specifically a pretreatment method for detecting gluten, a food allergen. Background Technology

[0002] In the food industry and hygiene supervision, accurate detection of food allergens is a key link in ensuring consumer safety. Gluten protein, as a complex protein, is widely found in processed grain foods. In order to obtain the protein components in the sample to be tested, it is usually necessary to first destroy the matrix structure of the food sample through a pretreatment process, extract the target protein encapsulated within it, and dissolve it in a specific buffer solution so that subsequent qualitative and quantitative analysis can be performed using techniques such as enzyme-linked immunosorbent assay (ELISA) or immunochromatographic test strips.

[0003] Existing methods for extracting food allergens generally rely on chemical treatment or conventional mechanical grinding. When processing highly processed foods, these methods often struggle to overcome the dense covalent cross-linked network formed by starch and lipids, resulting in the target protein being deeply encapsulated and unable to be fully released. This leads to low pretreatment extraction efficiency. Furthermore, in order to disrupt the dense matrix structure, existing processes often resort to high concentrations of chemical reducing agents or strong acids and bases. This chemical treatment destroys the disulfide bonds and higher-order folding structures between protein molecules, causing structural damage to the gluten protein antigenic epitopes of food allergens. This reduces the accuracy of subsequent immunological testing results and makes it difficult to meet the requirements for high-precision detection. Summary of the Invention

[0004] The first aspect of this invention provides a pretreatment method for detecting gluten, a food allergen, comprising the following steps: Feeding and premixing: The food sample particles are mixed with deionized water wetting liquid to obtain a semi-solid paste material, which is then fed into the pressure-bearing metal cavity; Variable lead extrusion and supercritical fluid injection: The variable lead extrusion screw inside the pressure-bearing metal cavity is driven to rotate, and carbon dioxide is pumped into the pressure-bearing metal cavity through the supercritical fluid supply module to maintain the supercritical fluid phase; the semi-solid paste material is subjected to mechanical shear force in the action area of ​​the variable lead extrusion screw. Microscopic penetration of cross-linked networks: Carbon dioxide in a supercritical fluid phase penetrates into the pores of the covalently cross-linked network of food sample particles; Transient pressure relief phase change cell disruption: When the material pushed by the pressure reaches the discharge end of the pressure-bearing metal cavity, the transient pressure relief module is triggered to discharge the material; the system pressure at the end of the pressure-bearing metal cavity decreases, and the carbon dioxide that has deeply penetrated into the food sample particles undergoes volume expansion phase change, generating expansion stress that causes the polymer skeleton to break, releasing the food allergen gluten protein wrapped in the covalent cross-linked network, which is transformed into a solid-gas mixture fluid composed of gaseous carbon dioxide and micron-sized food fragments and is ejected. Cold field construction and in-situ atomization capture: The coaxial annular atomization capture module, which is set outside the discharge port of the transient pressure relief module, is triggered to spray the extraction buffer. The solid-gas mixture impacts the coaxially sprayed extraction buffer, causing the extraction buffer to break into a micro liquid curtain. The local low temperature zone established by the gas expansion and cooling is used to extract gluten, a food allergen, in-situ, and obtain a liquid mixture containing gluten.

[0005] The variable lead extrusion screw body has a hollow shaft structure. Inside the hollow shaft structure, there is a cooling medium flow channel that extends along the axis and runs through it. During the variable lead extrusion and supercritical fluid injection steps, the temperature control circulation pump continuously introduces water or liquid carbon dioxide into the cooling medium flow channel as a cooling medium. The cooling medium circulates in the cooling medium flow channel, absorbing and carrying away the shear heat generated by mechanical friction in the external screw groove area, preventing the encapsulated food allergen gluten protein from undergoing structural denaturation or losing its antigenic epitope.

[0006] The food sample particles are deep-processed food sample particles. The covalently cross-linked network is a deep-processed food sample covalently cross-linked network composed of starch, lipids and proteins. Relying on the flow-blocking effect provided by the transient pressure relief module and the continuous injection pressure of the supercritical fluid supply module, the fluid pressure inside the pressure-bearing metal cavity is maintained above 7.38 MPa and the fluid temperature is above 31.1 degrees Celsius. Carbon dioxide molecules in the supercritical fluid phase penetrate into the microscopic free volume of the polymer skeleton of the deep-processed food sample covalently cross-linked network, weakening the intermolecular forces between molecular chain segments inside the food sample, causing the dense food sample matrix to swell in microscopic volume, thereby reducing the apparent kinematic viscosity of the semi-solid paste material.

[0007] In the transient pressure relief phase change cell disruption step, after receiving the opening pulse command, the high-frequency actuator of the transient pressure relief module drives the valve core to mechanically displace within a time window of less than ten milliseconds to perform full-open discharge, reducing the system pressure at the end of the pressure-bearing metal cavity to ambient pressure. An instantaneous pressure gradient is established between the discharge end of the pressure-bearing metal cavity and the external atmospheric pressure environment, causing the volume expansion phase change process to occur rapidly. This generates purely mechanical expansion stress from the inside out. The purely mechanical expansion stress overcomes the yield limit of the polymer skeleton, achieving the non-destructive physical release of the gluten protein antigen epitope without disrupting the folding state of the amino acid sequence of the food-source allergen gluten protein, and ejecting it in the form of a high-speed jet.

[0008] The annular nozzle of the coaxial annular atomizing and collecting module has an annular flow equalization cavity inside, which surrounds the central through hole. The central axis of the liquid inlet is tangential to the inner wall of the annular flow equalization cavity, forming a tangential liquid inlet structure. In the cold field construction and in-situ atomization and collecting steps, the extraction buffer enters the annular flow equalization cavity at high speed along the tangential direction to form a physical vortex and complete the physical pressure equalization distribution. After pressure equalization, the extraction buffer is sprayed downward at high speed through the annular liquid outlet gap at the lower end, forming a continuous and closed tubular liquid phase water curtain in the space surrounding the discharge port of the linear discharge channel of the transient pressure relief module, which envelops the sprayed solid-gas mixture fluid.

[0009] In the cold field construction and in-situ atomization and capture steps, the physical mechanism of gas expansion and cooling to establish a local low-temperature zone is as follows: gaseous carbon dioxide undergoes adiabatic expansion to the low-pressure external environment. During the adiabatic expansion process, it does work on the outside and absorbs the heat energy inside the expansion zone system. According to the thermodynamic principle of isenthalpic throttling expansion, a temperature drop is spontaneously generated. The temperature drop zone constructs a confined local low-temperature physical space in the geometric center region of the coaxial annular atomization and capture module. The local low-temperature physical space absorbs the residual mechanical frictional heat in the solid-gas mixture, lowering the overall temperature of the solid-gas mixture and maintaining it below the temperature threshold for thermal denaturation of gluten protein, a food allergen.

[0010] The extraction buffer is an extraction buffer containing surfactants. The physical mechanism of in-situ extraction is as follows: the solid-gas mixture acts as a shear flow field, vertically impacting and wiping the inner surface of the tubular liquid phase water curtain. The relative velocity difference between the gas phase carbon dioxide and the extraction buffer generates aerodynamic shear stress at the gas-liquid interface. The aerodynamic shear stress overcomes the surface tension of the extraction buffer, causing the dimensionless hydrodynamic parameters characterizing the droplet breakage state to exceed the critical limit for the fluid to maintain its original shape. This causes the tubular liquid phase water curtain to undergo aerodynamic breakage and disintegrate into micron-sized droplets. The surfactants contained inside the micron-sized droplets reduce the surface tension of the droplets and adhere to the surface of gluten, a food allergen, which undergoes spatial physical collision. The exposed gluten is completely encapsulated and extracted in situ within the internal buffer system of the micron-sized droplets through in-situ dissolution and conformational fixation.

[0011] During the pretreatment process, a multi-sensor coupled feedback control logic based on pressure and torque is executed synchronously: the system's main control computer synchronously receives the absolute pressure value returned by the high-frequency dynamic pressure sensor and the rotational resistance torque value returned by the dynamic torque sensor; when it is determined that the absolute pressure value reaches the set cell disruption pressure threshold, and at the same time it is determined that the rotational resistance torque value drops to the preset steady-state permeation torque range due to microscopic volume swelling, the system's main control computer synchronously sends two high-level trigger pulse signals through the output interface, which are transmitted to the high-frequency actuator of the transient pressure relief module and the external extractant supply pump without time delay.

[0012] Following the cold field construction and in-situ atomization and collection steps, the process also includes atomization product collection and centrifugal purification steps: a liquid mixture containing gluten, a food allergen, and accompanying high-speed gaseous carbon dioxide enter along the tangential trajectory of the spiral guide groove on the inner wall of the conical collection funnel, generating a centrifugal vortex. This causes the micron-sized droplets formed by the micro-liquid curtain to physically coalesce and converge on the inner wall surface, forming a macroscopic continuous liquid flow. The gaseous carbon dioxide, having lost its kinetic energy, is discharged into the external environment through the exhaust port. The crude extract at the bottom is collected and transferred to a refrigerated centrifuge where a centrifugal force field is applied to obtain the supernatant. The supernatant is then injected into a syringe filter equipped with a microporous membrane for pressure filtration to obtain the purified gluten extract.

[0013] A second aspect of the present invention provides a pretreatment system for detecting gluten, a food allergen, which applies the pretreatment method for detecting gluten, a food allergen, as described in the first aspect of the present invention, and includes: The feeding module is used to mix food sample particles with deionized water wetting solution and pump them in. The micro extrusion chamber module includes a pressure-bearing metal cavity with an external temperature-controlled jacket, and a variable-lead extrusion screw coaxially assembled inside the pressure-bearing metal cavity. The supercritical fluid supply module connects to the inside of the pressure-bearing metal cavity through a high-pressure fluid injection hole on the side wall of the pressure-bearing metal cavity, and is used to pump carbon dioxide into the inside of the pressure-bearing metal cavity; The transient pressure relief module is installed at the discharge end of the pressure-bearing metal cavity. It has an internal linear discharge channel and a high-frequency actuator with a mechanically connected valve core, which is used to generate expansion stress during discharge. The coaxial annular atomizing and collecting module is installed on the outer geometric periphery of the discharge port of the transient pressure relief module. It has a liquid inlet interface that is connected to an external extractant supply pump. It is used to obtain a liquid mixture containing gluten protein, a food allergen, by relying on the impact of the solid-gas mixture with the extraction buffer to form a micro liquid curtain and by utilizing the local low temperature zone established by the gas expansion and cooling.

[0014] This invention provides a pretreatment method for detecting gluten protein, a food allergen. It has the following beneficial effects: 1. This invention introduces a supercritical fluid transient phase transition and variable-lead mechanical shear coupling mechanism, utilizing the internal expansion stress generated when carbon dioxide transitions from a supercritical state to a gaseous state. This achieves efficient physical disruption of the covalently cross-linked network of deeply processed foods and the non-destructive release of gluten, a food allergen, without the need for strong acids, strong bases, or chemical reducing agents to damage protein disulfide bonds. This preserves the natural higher-order folding of the gluten protein amino acid sequence, ensuring the integrity of the antigen epitope structure in subsequent immunological detection and thus improving the accuracy of the detection results.

[0015] 2. This invention utilizes the Joule-Thomson cooling effect generated during the adiabatic expansion of carbon dioxide to construct a local low-temperature physical space in the space outside the transient pressure relief discharge port. This local low-temperature physical space coincides with the path of the high-speed jet solid-gas mixture, allowing the local low-temperature physical space to absorb the residual heat generated by mechanical shear friction. This maintains the extraction environment of gluten protein, a food allergen, below the temperature threshold for antigenic epitope denaturation, effectively avoiding the inactivation of the target protein due to shear heat generation during the extraction process.

[0016] 3. This invention establishes a sensor-coupled feedback control logic triggered by both pressure and torque conditions. It maps the rotational resistance torque, which characterizes the plasticization degree of semi-solid paste materials, with the fluid pressure inside the cavity in real time. It uses the nonlinear decrease in the rotational resistance torque due to microscopic volume swelling to determine the permeation state of supercritical carbon dioxide. Transient pressure relief and atomization capture are triggered only when the rotational resistance torque reaches the steady-state permeation range and the pressure reaches the cell-wall breaking threshold. This achieves precise and uniform release of physical cell-wall breaking energy inside the food sample, improving the reliability of pretreatment operations. Attached Figure Description

[0017] Figure 1 This is a system architecture and workflow diagram of the present invention. Detailed Implementation

[0018] The technical solutions in 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 embodiments of the present invention, and not all embodiments. 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.

[0019] Example: See attached document Figure 1 , Figure 1This is a system architecture and workflow diagram based on the linkage of supercritical fluid transient phase change and thermodynamics according to an embodiment of the present invention. The pretreatment system for detecting gluten protein, a food allergen, mainly consists of a feeding module, a micro extrusion chamber module, a supercritical fluid supply module, a transient pressure relief module, and a coaxial annular atomization and collection module.

[0020] The feeding module includes a precision twin-screw quantitative feeder or a gravity-type powder loss-in-weight weigher. The micro-extrusion chamber module includes a pressure-bearing metal chamber with a temperature-controlled jacket on the outside. A variable lead extrusion screw is coaxially arranged inside the pressure-bearing metal chamber. The supercritical fluid supply module includes a dual-plunger high-pressure horizontal flow pump and a refrigeration circulation loop. The supercritical fluid supply module is connected to the inside of the pressure-bearing metal chamber through a high-pressure resistant one-way valve on the side wall of the pressure-bearing metal chamber. The transient pressure relief module is assembled at the discharge end of the pressure-bearing metal chamber. The transient pressure relief module includes an electromagnetic direct-acting high-pressure ball valve, a pneumatic diaphragm quick-cut-off valve, or a needle-type unloading valve with servo drive. The coaxial annular atomizing and collecting module is fitted around the outer geometric periphery of the discharge port of the transient pressure relief module. The coaxial annular atomizing and collecting module has an independent liquid phase delivery pipeline, which is connected to an external extraction buffer storage tank and a high-pressure plunger pump.

[0021] S100, Feeding and Premixing: The deep-processed food sample particles and deionized water wetting solution are mixed according to a preset solid-liquid ratio and fed into the pressure-bearing metal cavity through the feeding module.

[0022] S200, Variable Lead Extrusion and Supercritical Fluid Injection: The servo motor drives the variable lead extrusion screw to rotate. The supercritical fluid supply module continuously pumps carbon dioxide through the high-pressure resistant one-way valve on the side wall. The fluid in the pressure-bearing metal cavity is kept in a supercritical state by heating through the temperature-controlled jacket and the back pressure established by the end extrusion. The effective volume of the screw groove of the variable lead extrusion screw gradually decreases along the axial advancement direction. The solid-liquid-gas mixture is subjected to progressively enhanced mechanical shear force in the action area of ​​the variable lead extrusion screw, and large-particle food samples are broken down by mechanical shear force.

[0023] Specifically, step S200 also includes the following steps: S210, Sample Grinding and Wetting: High-temperature deep-processed food samples are placed in a mechanical grinding device for grinding. After sieving through a standard sieve, solid powder with uniform particle size is obtained. Deionized water is injected into the solid powder for wetting and premixing. The mixing ratio of deionized water and solid powder is adjusted so that the solid powder absorbs deionized water and forms a hydration layer on the surface. The discrete solid powder is transformed into a semi-solid paste material with physical fluidity. The semi-solid paste material has the initial viscosity conditions suitable for subsequent extrusion and propulsion. The semi-solid paste material is quantitatively pumped into the feed end of the pressure-bearing metal cavity by the feeding module.

[0024] S220, Screw Partition Extrusion: A variable lead extrusion screw is coaxially assembled inside the pressure-bearing metal cavity. The body of the variable lead extrusion screw is a hollow shaft structure. A cooling medium flow channel extending along the axis and penetrating through the hollow shaft structure is opened inside. The cooling medium flow channel is connected to an external temperature control circulation pump. The temperature control circulation pump continuously introduces water or liquid carbon dioxide into the cooling medium flow channel as a cooling medium. The cooling medium circulates in the cooling medium flow channel, absorbing and carrying away the shear heat generated by mechanical friction in the external screw groove area, maintaining the temperature inside the pressure-bearing metal cavity within a preset low-temperature protection range, and preventing the gluten protein inside the high-temperature deep-processed food sample from undergoing structural denaturation or loss of antigenic epitopes due to abnormal heating.

[0025] The outer surface of the variable lead extrusion screw is machined with continuous helical thread ridges. Along the material propulsion direction, i.e., along the axial spatial coordinate of the pressure-bearing metal cavity, the variable lead extrusion screw is geometrically divided into a feeding section, a compression section, and a metering section. In the feeding section, the pitch and effective depth of the screw groove remain constant. The feeding section contains semi-solid paste material and conveys it to the subsequent processing section. In the compression section, the pitch and effective depth of the screw groove decrease non-linearly. The available flow cross-sectional area between the inner wall of the pressure-bearing metal cavity and the outer surface of the screw groove gradually decreases, so that the semi-solid paste material is continuously compacted during the propulsion process. In the metering section, the pitch and effective depth of the screw groove decrease to the system minimum and remain constant, forming a shear slit area at the discharge end.

[0026] Driven by the rotation of the servo motor, the semi-solid paste material is subjected to progressively increasing mechanical shear stress within the screw channel. The local shear rate of the semi-solid paste material at any axial position within the screw channel satisfies the following formula: In the formula, Represents the axial spatial coordinates along the variable lead extrusion screw, in meters (m). Indicates axial position Local shear rate at the location, in units of ; This indicates the characteristic outer diameter of the variable lead extrusion screw, in meters (m). This indicates the rotational angular velocity of the variable lead extrusion screw, expressed in rev / s. Indicates axial position The effective depth of the local screw groove, in meters.

[0027] Under the above structural design, the variable lead extrusion screw gradually reduces the effective depth of the local screw grooves in the compression and metering sections. This leads to a significant increase in the local shear rate. The mechanical shear force associated with the local shear rate causes large-particle food samples to mechanically yield and break apart, thereby greatly increasing the specific surface area of ​​the solid food sample. This exposes the dense polymer skeleton structure composed of cross-linked starch and lipids inside the food sample, providing a physical contact interface for the subsequent deep penetration of supercritical fluids.

[0028] S230. Supercritical State Construction and Maintenance: The supercritical fluid supply module continuously injects carbon dioxide into the pressure-bearing metal cavity through a high-pressure fluid injection hole opened on the side wall of the pressure-bearing metal cavity. The high-pressure fluid injection hole is equipped with a microporous sintered filter element and a spring-loaded one-way valve. The microporous sintered filter element prevents semi-solid paste-like materials from entering the high-pressure fluid injection hole, and the spring-loaded one-way valve prevents high-pressure materials inside the pressure-bearing metal cavity from flowing back to the supercritical fluid supply module. The specific lower-level features of the supercritical fluid supply module include a dual-plunger high-pressure horizontal flow pump equipped with a front-end refrigeration pipeline. The dual-plunger high-pressure horizontal flow pump continuously pressurizes the liquid carbon dioxide to a set pressure threshold and pumps the high-pressure liquid carbon dioxide into the screw groove working area of ​​the pressure-bearing metal cavity. The pressure-bearing metal cavity is fitted with a temperature control jacket. The specific lower-level features of the temperature control jacket include a heat transfer oil circulation jacket or an electromagnetic heating coil attached to and wrapped around the outer wall of the pressure-bearing metal cavity. The temperature control jacket transfers heat to the inside of the pressure-bearing metal cavity, increasing the temperature of the carbon dioxide injected into the pressure-bearing metal cavity.

[0029] The transient pressure relief module at the control end maintains a slightly open throttling state. Relying on the flow restriction provided by the transient pressure relief module and the continuous injection pressure of the dual-plunger high-pressure parallel flow pump, the fluid pressure inside the pressure-bearing metal cavity is stably maintained above 7.38 MPa. Simultaneously, with the continuous heating of the temperature control jacket, the fluid temperature inside the pressure-bearing metal cavity is maintained above 31.1 degrees Celsius. Carbon dioxide under the above critical pressure and critical temperature conditions is transformed into a supercritical fluid phase.

[0030] S240, Fluid Dynamics Synergy and Cross-linking Network Deep Penetration: In the compression and metering sections of the pressure-bearing metal cavity, the variable-lead extrusion screw applies a progressively enhanced high shear stress field to the semi-solid paste material. The mechanical shear force tears the semi-solid paste material, forcing the large starch particles and lipid clusters in the semi-solid paste material to physically break down. Carbon dioxide in the supercritical fluid phase has low kinetic viscosity, high surface diffusion coefficient and high fluid density.

[0031] As the physical interfaces are continuously updated during the mechanical shearing and fragmentation process, carbon dioxide in the supercritical fluid phase, acting as a highly permeable medium, penetrates into the pores of the covalently cross-linked network of processed food composed of starch, lipids, and gluten protein. The supercritical fluid phase carbon dioxide molecules permeate into the microscopic free volume of the covalently cross-linked network polymer backbone, weakening the intermolecular forces between molecular chain segments within the food sample. This causes microscopic volume swelling of the dense food sample matrix, reducing the apparent kinematic viscosity of the semi-solid paste. This provides a fluid energy storage space distributed within the food sample matrix for the subsequent transient phase change cell disruption. This microscopic permeation step establishes the material permeation basis for the pretreatment of gluten protein, a food allergen, and establishes the physical conditions under which cell disruption energy can be uniformly released within the food sample.

[0032] S300, cross-linked network micro-penetration: Food samples dispersed by prior mechanical shearing increase the solid-liquid contact area, and carbon dioxide in a supercritical state penetrates into the pores of the covalently cross-linked network of the deep-processed food sample, which is composed of starch, lipids and proteins.

[0033] S400 Transient Pressure Relief Phase Change Cell Breaking: When the material pushed by the compression reaches the discharge end of the pressure-bearing metal cavity, the control center triggers the transient pressure relief module to execute full-open discharge. The system pressure at the end of the pressure-bearing metal cavity drops to the ambient pressure within a preset time window, causing the carbon dioxide that has penetrated deep into the food sample to undergo a rapid volume expansion phase change, generating microscopic physical expansion stress from the inside out. The expansion stress overcomes the yield limit of the polymer backbone of the cross-linked network of the food sample and causes the polymer backbone to break, releasing the food-derived allergen gluten protein wrapped in the cross-linked network structure.

[0034] Specifically, step S400 also includes the following steps: S410, Pressure Relief Channel and Anti-clogging Valve Body Structure: The transient pressure relief module is fluidly connected to the discharge end of the pressure-bearing metal cavity. To meet the discharge requirements of semi-solid paste materials containing food sample particles and to avoid shear blockage of materials during discharge, the lower part of the transient pressure relief module adopts a straight-through high-pressure slide valve or a full-bore high-pressure ball valve. The transient pressure relief module has a straight discharge channel parallel to the axis of the discharge end of the pressure-bearing metal cavity. The straight discharge channel does not have a reducing or flow-blocking baffle. This ensures that when the straight discharge channel is fully open, the internal fluid flow cross-sectional area is equal to the cross-sectional area of ​​the discharge end of the pressure-bearing metal cavity. The valve core surface of the transient pressure relief module and the inner wall of the straight discharge channel are coated with a polytetrafluoroethylene (PTFE) wear-resistant coating. The PTFE wear-resistant coating reduces the mechanical friction resistance during valve core movement and prevents the adhesion of high-pressure semi-solid paste materials.

[0035] S420, Millisecond-level Electrical Response and Actuator: The valve core of the transient pressure relief module is mechanically connected to a high-frequency actuator. The lower-level features of the high-frequency actuator include a high-power piezoelectric ceramic actuator or a high-speed electromagnetic pilot pneumatic cylinder. The high-frequency actuator is electrically connected to the system main control computer. Under normal extrusion conditions, the high-frequency actuator applies a closing holding force to the valve core, and the valve core is in a slightly open throttling state or a completely closed state, maintaining the supercritical high-pressure conditions inside the pressure-bearing metal cavity.

[0036] S430, Pressure Threshold Monitoring and Action Triggering: A high-frequency dynamic pressure sensor is embedded in the side wall of the pressure-bearing metal cavity. The probe of the high-frequency dynamic pressure sensor directly contacts the material fluid inside the pressure-bearing metal cavity. The high-frequency dynamic pressure sensor collects the absolute pressure value inside the pressure-bearing metal cavity in real time and converts the absolute pressure value into an analog electrical signal, which is then transmitted to the system's main control computer. When the variable lead extrusion screw pushes the semi-solid paste material fully permeated with supercritical carbon dioxide to the discharge end, and the pressure value fed back by the high-frequency dynamic pressure sensor reaches the set cell breaking pressure threshold, the system's main control computer sends an start pulse command to the high-frequency actuator.

[0037] Upon receiving the opening pulse command, the high-frequency actuator drives the valve core to undergo mechanical displacement within a time window of less than 10 milliseconds, instantly bringing the linear discharge channel to a fully open position. This millisecond-level discharge response ensures the establishment of a significant instantaneous pressure gradient on both sides of the discharge end of the pressurized metal cavity, preventing the slow release of pressure and subsequent gradual material outflow. A steep pressure gradient is a physical prerequisite for inducing transient volume expansion and generating physical tearing energy in supercritical fluids. Establishing this steep pressure gradient ensures that the crucial phase-change cell disruption action in the pretreatment method for detecting gluten, a food allergen, is triggered. S440, Phase Change and Expansion Stress Generation: When the transient pressure relief module is in the fully open position, an instantaneous pressure gradient is established between the discharge end of the pressure-bearing metal cavity and the external atmospheric pressure environment. The environmental pressure of carbon dioxide infiltrating into the micropores inside the food sample drops sharply. The pressure drop disrupts the thermodynamic equilibrium conditions of the supercritical phase. The carbon dioxide infiltrating into the food sample changes from the supercritical fluid phase to gaseous carbon dioxide across the phase boundary. Accompanying the phase change process, the gaseous carbon dioxide undergoes violent volume expansion, generating pure physical and mechanical expansion stress from the inside out inside the micropores of the food sample.

[0038] S450, Microscopic Physical Tearing and Matrix Disintegration: The mechanical expansion stress generated by gaseous carbon dioxide directly acts on the covalently cross-linked network of deep-processed food composed of starch and lipids inside the food sample. The mechanical expansion stress rises rapidly within milliseconds. When the mechanical expansion stress exceeds the mechanical yield limit of the polymer skeleton of the covalently cross-linked network of deep-processed food, the polymer skeleton undergoes physical fracture. The physical fracture process of the polymer skeleton disintegrates the originally dense large-particle food sample into dispersed micron-sized food fragments.

[0039] S460. Non-destructive release of gluten protein antigenic epitopes: The physical breaking of the covalent cross-linked network in processed foods removes the spatial encapsulation barrier of the food sample to the target extract. Gluten protein, a food allergen originally encapsulated within the covalent cross-linked network of processed foods, is exposed on the surface of micron-sized food fragments. Because the volume expansion phase transition process only generates purely mechanical expansion stress and does not involve the use of strong acids, strong bases, or chemical reducing agents that disrupt protein disulfide bonds, the purely mechanical expansion stress cannot disrupt the folding state of the gluten protein amino acid sequence. The three-dimensional spatial structure of gluten protein and the antigenic epitopes closely related to subsequent immunological detection are completely preserved, achieving non-destructive physical exposure of gluten protein and meeting the requirements for target substance activity and detection accuracy in the pretreatment method for detecting gluten protein, a food allergen.

[0040] S470, Material Flow Transformation and High-Speed ​​Jet Formation: Accompanied by the microscopic physical tearing and matrix disintegration process, the macroscopic flow state of the material at the discharge end of the pressure-bearing metal cavity changes. The material changes from a two-phase mixture containing semi-solid paste and supercritical carbon dioxide to a solid-gas mixture fluid composed of a large amount of gaseous carbon dioxide and micron-sized food fragments. The gaseous carbon dioxide released by the rapid expansion of volume has extremely high flow velocity and kinetic energy. The gaseous carbon dioxide carries micron-sized food fragments and gluten protein with exposed antigenic epitopes on the surface and is ejected from the linear discharge channel of the transient pressure relief module in the form of a high-speed jet. The high-speed jet solid-gas mixture fluid directly enters the working area of ​​the coaxial annular atomizing capture module, converting the kinetic energy of the gaseous fluid generated by the phase change expansion into the pneumatic crushing energy source for the subsequent liquid phase capture step.

[0041] S500, Cold Field Construction and In-situ Atomization Collection: Simultaneously with the operation of the transient pressure relief module, the coaxial annular atomization collection module is triggered to pressurize and spray extraction buffer containing surfactants outward through the internal flow channel. At the moment of pressure relief, the high-pressure gas expands adiabatically into the low-pressure environment, doing work and absorbing internal energy of the system, establishing a local low-temperature zone to provide thermal protection for heat-sensitive gluten proteins. The solid-gas mixed jet generated after the phase transition acts as the shear flow field driving force, impacting and tearing the coaxially ejected extraction buffer. The extraction buffer is broken into a micro-liquid curtain under the impact of the airflow, performing in-situ dissolution and conformational fixation extraction of the gluten proteins ejected with the flow, forming a liquid mixture containing stable antigenic epitopes of gluten proteins, which serves as the pretreatment solution for subsequent gluten protein detection.

[0042] Specifically, step S500 also includes the following steps: S510, Coaxial Nested Spatial Structure Construction: A coaxial annular atomizing and collecting module is sleeved on the outside of the discharge end of the transient pressure relief module. The lower feature of the coaxial annular atomizing and collecting module includes an annular nozzle body made of stainless steel. The annular nozzle body has a central through hole inside. The end tube of the linear discharge channel of the transient pressure relief module passes into the central through hole. The central axis of the linear discharge channel and the central axis of the annular nozzle body are absolutely coincident in space, establishing a nested spatial structure. The nested spatial structure defines the geometric center region of the solid-gas mixture fluid ejected from the linear discharge channel.

[0043] S520, Internal Flow Equalization Channel and Annular Liquid Curtain Generation: An annular flow equalization cavity surrounding a central through-hole is formed inside the annular nozzle body. An inlet port is located on the outer wall of the annular nozzle body, with its central axis tangential to the inner wall of the annular flow equalization cavity, creating a tangential inlet structure within the annular nozzle body. The inlet port connects to an external independent liquid phase delivery pipeline and the annular flow equalization cavity. An extractant supply pump is installed on the liquid phase delivery pipeline. Specific features of the extractant supply pump include a high-pressure precision plunger pump. The inlet end of the high-pressure precision plunger pump connects to an external storage tank containing an extraction buffer solution containing surfactants. An annular outlet slit is formed on the lower end face of the annular nozzle body, connecting to the annular flow equalization cavity. The flow equalization chamber is connected to the external environment. The annular liquid outlet slit surrounds the end of the linear discharge channel of the transient pressure relief module at a 360-degree angle. The high-pressure precision plunger pump pressurizes the extraction buffer into the inlet interface. The extraction buffer enters the annular flow equalization chamber at high speed along the tangential direction and forms a physical vortex inside the annular flow equalization chamber. The physical vortex eliminates the local pressure difference in various directions of the annular flow equalization chamber and completes the physical pressure equalization distribution of the extraction buffer. The equalized extraction buffer is sprayed downward at high speed along the annular liquid outlet slit, forming a continuous and closed tubular liquid phase water curtain in the outer space of the discharge port of the linear discharge channel. The continuous and closed tubular liquid phase water curtain constitutes a physical barrier to prevent the escape of gluten protein, a food allergen, from the subsequent release into the outer space.

[0044] S530 Electrical Linkage Control Circuit Design: The control terminal of the high-pressure precision plunger pump is electrically connected to the system main control computer. The system main control computer establishes a synchronous linkage control circuit between the high-pressure precision plunger pump and the transient pressure relief module actuator. When the system main control computer detects that the internal pressure of the pressure-bearing metal cavity reaches the wall breaking pressure threshold and sends an opening pulse command to the transient pressure relief module, the system main control computer synchronously sends a full-power operation command to the high-pressure precision plunger pump. The synchronous linkage control circuit eliminates the time difference of mechanical start-up, ensuring that the closed tubular liquid phase water curtain is formed before or synchronously with the high-speed solid-gas mixed jet carrying the food allergen gluten. The tubular liquid phase water curtain completely envelops the high-speed solid-gas mixed jet inside the tubular liquid phase water curtain, establishing a physical barrier and in-situ contact microenvironment boundary for the pretreatment method of detecting the food allergen gluten.

[0045] S540, Adiabatic Expansion and Isoenthalpic Cooling: When the transient pressure relief module is in the fully open position, carbon dioxide in the supercritical fluid phase inside the pressure-bearing metal cavity is affected by the sudden change in environmental pressure and is injected into the normal pressure external environment through the linear discharge channel of the transient pressure relief module. The carbon dioxide gas undergoes adiabatic expansion towards the low-pressure external environment. During the adiabatic expansion process, it does work on the outside and absorbs the heat energy inside the system in the expansion region. The thermodynamic state change of the carbon dioxide gas follows the following Joule-Thomson coefficient formula: In the formula, The Joule-Thomson coefficient for carbon dioxide gas is expressed in K / Pa. Represents the absolute temperature of an expanding fluid system, expressed in Kelvin (K). This represents the pressure of an expanding fluid system, expressed in Pa. It represents the specific enthalpy per unit mass of an expanding fluid system, with units of J / kg; This represents the specific heat capacity at constant pressure of carbon dioxide gas, expressed in J / (kg·K). The specific volume of carbon dioxide gas is expressed in units of 1000 m³ / s. .

[0046] S550, Targeted Cold Field Distribution Structure: Carbon dioxide drops rapidly from a supercritical high-pressure state to an atmospheric pressure state, resulting in a negative pressure change in physical conditions. Since the Joule-Thomson coefficient of carbon dioxide under extrusion conditions is greater than zero, the expansion fluid system spontaneously generates a temperature drop. The temperature drop area is spatially concentrated in front of the discharge port of the transient pressure relief module. The system uses the annular water curtain of the coaxial annular atomizing capture module as the outer boundary to construct a confined local low-temperature physical space in the geometric center region of the coaxial annular atomizing capture module.

[0047] S560, Mechanical Heat Offset and Antigenic Epitope Protection: In the preceding propulsion step, the variable lead extrusion screw continuously applies mechanical shear to the semi-solid paste material. The work done by mechanical shear is converted into mechanical frictional heat, which is transferred along the semi-solid paste material and accumulates inside it. The mechanical frictional heat accumulated inside can cause irreversible thermal denaturation of gluten, a food allergen. The local low-temperature physical space is completely overlapped in three-dimensional space with the injection path of the solid-gas mixture carrying gluten. When the solid-gas mixture is injected into the local low-temperature physical space, the local low-temperature physical space absorbs the residual mechanical frictional heat in the solid-gas mixture, lowering the overall temperature of the solid-gas mixture and maintaining it below the temperature threshold for thermal denaturation of gluten. The thermodynamic cooling compensation offsets the heat accumulation damage caused by mechanical extrusion. From the physical level of temperature control, it ensures that the higher-order folding structure of gluten exposed to the external environment is not damaged by heat, preserving the undamaged biochemical antigenic epitopes for subsequent immunological detection.

[0048] S570, Pneumatic Crushing and Droplet Generation: The solid-gas mixture ejected by the transient pressure relief module has high flow kinetic energy. The solid-gas mixture is ejected downstream at high speed along the central axis of the straight discharge channel. The extraction buffer is ejected from the annular liquid outlet slit of the coaxial annular atomizing and collecting module, forming a tubular liquid phase water curtain. The solid-gas mixture vertically impacts and rubs against the inner surface of the tubular liquid phase water curtain. There is a relative velocity difference between the solid-gas mixture and the extraction buffer. The relative velocity difference generates aerodynamic shear stress at the gas-liquid interface.

[0049] Pneumatic shear stress overcomes the surface tension of the extraction buffer, tearing it apart. The tubular liquid phase water curtain undergoes aerodynamic fragmentation, breaking into micron-sized droplets. The degree of fragmentation due to the interaction between the gas and liquid phases is constrained by the following Weber number formula: In the formula, The dimensionless Weber number represents the evaluation of droplet breakup state; This represents the equivalent density of gaseous carbon dioxide in the solid-gas mixture after the expansion phase change, expressed in units of... ; It represents the relative velocity difference between the gaseous carbon dioxide and the extraction buffer interface, in m / s; The characteristic diameter of the micron-sized droplets generated after the collision and breakup is expressed in meters (m). The surface tension of the extraction buffer is expressed in N / m. When the relative velocity difference causes the Weber number to exceed the critical value for the extraction buffer to maintain the droplet shape, the extraction buffer is continuously refined, forming a dense atomized liquid curtain in the local low-temperature physical space.

[0050] S580, Spatial Collision and In-situ Capture: A solid-gas mixture carries micron-sized food fragments and gluten proteins with exposed antigenic epitopes. The gluten proteins collide with a dense atomized liquid curtain in a localized low-temperature physical space. The micron-sized droplets contain surfactants, which reduce the surface tension of the micron-sized droplets and enhance their wettability on the surface of the gluten proteins. The micron-sized droplets adhere to the surface of the gluten proteins, completely encapsulating the exposed gluten proteins and dissolving them in the internal buffer system of the micron-sized droplets.

[0051] In-situ extraction of gluten protein is performed using an atomized liquid curtain within a localized low-temperature physical space. This in-situ extraction avoids secondary aggregation or spatial conformational folding of gluten protein in a dry external air environment. Micron-sized droplets containing dissolved gluten protein settle under the downward force of gravity and accompanying airflow, accumulating to form a liquid mixture containing stable antigenic epitopes of gluten protein. This liquid mixture serves as a pretreatment product for the detection of gluten protein as a food allergen and proceeds to subsequent separation and collection processes.

[0052] S600, Collection and Centrifugal Purification of Atomized Products: Collect the liquid mixture and perform physical separation of components to obtain purified gluten protein extract.

[0053] Specifically, step S600 also includes the following steps: S610, Conduction and Condensation of Gas-Liquid-Solid Mixtures: A liquid mixture containing the stable antigenic epitope gluten protein settles downwards from the bottom of a coaxial annular atomizing and collecting module. A conical collecting funnel is located directly below the coaxial annular atomizing and collecting module. The inner wall of the conical collecting funnel has a spiral guide groove. The liquid mixture and the accompanying high-speed gaseous carbon dioxide enter the conical collecting funnel along the tangential trajectory of the spiral guide groove. Under the physical guidance of the spiral guide groove, the high-speed gaseous carbon dioxide and the liquid mixture generate a centrifugal vortex. The centrifugal vortex forces the micron-sized droplets in the liquid mixture to impact the inner wall of the conical collecting funnel under centrifugal force. The micron-sized droplets physically coalesce and converge on the inner wall to form a macroscopic continuous liquid flow. The macroscopic continuous liquid flow slides down the inner wall under gravity to the bottom outlet of the conical collecting funnel. The gaseous carbon dioxide, having lost kinetic energy, is discharged into the external environment through the exhaust hole reserved on the top periphery of the conical collecting funnel. The gas-liquid separation structure avoids the splashing of the collected liquid and the phenomenon of a large amount of foaming caused by the high-speed airflow directly impacting the bottom liquid surface.

[0054] S620, Centrifugal Precipitation and Physical Separation of Components: The bottom outlet of the conical collection funnel is connected to the centrifugal collection tube to obtain a crude extract containing dissolved gluten protein and insoluble food matrix residues. The centrifugal collection tube containing the crude extract is transferred to a refrigerated centrifuge. The operating temperature of the refrigerated centrifuge is set between 2 and 8 degrees Celsius. The low-temperature physical environment protects the activity of the higher folding structure of gluten protein. Under the action of the preset centrifugal force field provided by the refrigerated centrifuge, the denser insoluble starch particles, lipid clusters, and cell wall debris in the crude extract settle towards the bottom of the centrifugal collection tube, compacting to form a solid precipitate at the bottom of the centrifugal collection tube. The food allergen gluten protein, which is completely dissolved in the surfactant buffer system, is released and retained in the supernatant.

[0055] S630. Supernatant Collection and Sample Preparation: Extract the supernatant after solid-liquid separation and inject it into a syringe filter equipped with a microporous membrane for pressure filtration. The nominal pore size of the microporous membrane is 0.22 micrometers or 0.45 micrometers. During the pressure filtration process, the microporous membrane traps the tiny suspended particles remaining in the supernatant, obtaining a purified gluten protein extract. The purified gluten protein extract is directly used as the standard sample solution for enzyme-linked immunosorbent assay (ELISA) or immunochromatographic test strip detection equipment, completing the entire pretreatment process for the detection of gluten protein in processed foods.

[0056] S700, Multi-sensor Coupled Feedback Control Logic: Simultaneously executes multi-sensor coupled monitoring based on pressure and torque during the preprocessing stage.

[0057] Specifically, step S700 also includes the following steps: S710 Multi-source sensor hardware layout: A miniature temperature sensor and a high-frequency dynamic pressure sensor are embedded in the sidewall of the internal flow channel of the pressure-bearing metal cavity. The probes of the miniature temperature sensor and the high-frequency dynamic pressure sensor are in direct contact with the solid-liquid-gas three-phase mixture flowing inside the pressure-bearing metal cavity. A dynamic torque sensor is connected in series at the output shaft of the drive servo motor of the variable lead extrusion screw. The input interface of the system main control computer is electrically connected to the miniature temperature sensor, the high-frequency dynamic pressure sensor, and the dynamic torque sensor. The output interface of the system main control computer is electrically connected to the high-frequency actuator of the transient pressure relief module, the extractant supply pump, and the power regulator of the temperature control jacket.

[0058] S720, Physical State Coupling Monitoring and Logic Judgment: When the variable lead extrusion screw mechanically shears and conveys semi-solid paste materials, the system's main control computer synchronously receives absolute temperature values ​​from a micro temperature sensor, absolute pressure values ​​from a high-frequency dynamic pressure sensor, and rotational resistance torque values ​​from a dynamic torque sensor at a millisecond-level sampling period. The logic operation unit inside the system's main control computer executes a closed-loop comparison program. The system's main control computer first compares the absolute temperature value with the set protein thermal denaturation safety temperature threshold. If the absolute temperature value approaches the protein thermal denaturation safety temperature threshold, the system's main control computer controls the temperature control jacket to reduce the heating power and increase the cooling fluid flow rate in the cooling medium circulation channel.

[0059] S730, Pressure and Torque Dual-Condition Trigger Mechanism: For the core transient phase change cell disruption action, the system's main control computer uses pressure and torque dual-condition trigger logic. As supercritical carbon dioxide continuously penetrates into the covalently cross-linked network of the deep-processed food, it causes microscopic volume swelling of the polymer skeleton. This microscopic volume swelling leads to a nonlinear decrease in the macroscopic apparent viscosity of the semi-solid paste material. The decrease in macroscopic apparent viscosity is directly reflected in the reduction and stabilization of the rotational resistance torque value collected by the dynamic torque sensor. The system's main control computer determines that the absolute pressure value has reached the set cell disruption pressure threshold, and at the same time determines that the rotational resistance torque value has decreased to within the preset steady-state penetration torque range. The simultaneous satisfaction of both conditions indicates that the supercritical carbon dioxide has completely penetrated the food sample matrix.

[0060] S740, millisecond-level electrical synchronous execution: At the instant the dual-condition judgment is met, the system's main control computer synchronously sends two high-level trigger pulse signals through the output interface. The first high-level trigger pulse signal is transmitted to the high-frequency actuator of the transient pressure relief module, driving the valve core of the transient pressure relief module to instantly reach the fully open position, executing the transient pressure relief phase change cell breaking action. The second high-level trigger pulse signal is transmitted to the extraction liquid supply pump without time delay, controlling the extraction liquid supply pump to pressurize the extraction buffer at full load, constructing a tubular liquid phase water curtain that envelops the discharge port. Through the underlying physical coupling of multi-sensor data, the precise docking of mechanical shearing, phase change cell breaking and in-situ liquid phase capture in physical space and electrical timing is ensured, completing the highly reliable extraction of gluten protein, a food allergen.

[0061] For the selection of the underlying hardware of the system's main control computer, the configuration of the data acquisition card, and the design of the analog-to-digital conversion circuit, those skilled in the art can use conventional industrial programmable logic controllers and matching analog input / output modules to implement them. These are well-known technologies in the field and will not be elaborated upon here. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pretreatment method for detecting gluten protein, a food allergen, characterized in that, Includes the following steps: Feeding and premixing: The food sample particles are mixed with deionized water wetting liquid to obtain a semi-solid paste material, which is then fed into the pressure-bearing metal cavity; Variable lead extrusion and supercritical fluid injection: The variable lead extrusion screw inside the pressure-bearing metal cavity is driven to rotate, and carbon dioxide is pumped into the pressure-bearing metal cavity through the supercritical fluid supply module to maintain the supercritical fluid phase; the semi-solid paste material is subjected to mechanical shear force in the action area of ​​the variable lead extrusion screw. Microscopic penetration of cross-linked network: Carbon dioxide in a supercritical fluid phase penetrates into the covalently cross-linked network pores of the food sample particles; Transient pressure relief phase change cell disruption: When the material pushed by the pressure reaches the discharge end of the pressure-bearing metal cavity, the transient pressure relief module is triggered to discharge the material; the system pressure at the end of the pressure-bearing metal cavity decreases, and the carbon dioxide that has deeply penetrated into the food sample particles undergoes a volume expansion phase change, generating expansion stress that causes the polymer skeleton to break, releasing the food allergen gluten protein wrapped in the covalent cross-linked network, which is transformed into a solid-gas mixture fluid composed of gaseous carbon dioxide and micron-sized food fragments and is ejected. Cold field construction and in-situ atomization and collection: The coaxial annular atomization and collection module, which is sleeved outside the discharge port of the transient pressure relief module, is triggered to spray the extraction buffer solution; the solid-gas mixture impacts the coaxially sprayed extraction buffer solution, causing the extraction buffer solution to break into a micro liquid curtain. The local low temperature zone established by the gas expansion and cooling is used to extract the food allergen gluten protein in situ, and a liquid mixture containing the food allergen gluten protein is obtained.

2. The pretreatment method for detecting gluten, a food allergen, according to claim 1, is characterized in that, The variable lead extrusion screw has a hollow shaft structure, and a cooling medium flow channel extending along the axis and penetrating inside the hollow shaft structure. In the variable lead extrusion and supercritical fluid injection steps, an external temperature-controlled circulating pump continuously introduces water or liquid carbon dioxide into the cooling medium flow channel as a cooling medium. The cooling medium circulates within the cooling medium flow channel, absorbing and carrying away the shear heat generated by mechanical friction in the external spiral groove area, preventing the encapsulated food allergen gluten protein from undergoing structural denaturation or losing its antigenic epitopes due to abnormal heating.

3. The pretreatment method for detecting gluten, a food allergen, according to claim 1, is characterized in that, In the cross-linked network micro-penetration step, the food sample particles are deep-processed food sample particles, and the covalent cross-linked network is a deep-processed food sample covalent cross-linked network composed of starch, lipids and proteins. Relying on the flow-blocking effect provided by the transient pressure relief module and the continuous injection pressure of the supercritical fluid supply module, the fluid pressure inside the pressure-bearing metal cavity is maintained above 7.38 MPa and the fluid temperature is maintained above 31.1 degrees Celsius. Carbon dioxide molecules in the supercritical fluid phase penetrate into the microscopic free volume of the covalently cross-linked polymer backbone of the deep-processed food sample, weakening the intermolecular forces between molecular chain segments inside the food sample, causing the dense food sample matrix to swell in the microscopic volume, thereby reducing the apparent kinematic viscosity of the semi-solid paste material.

4. The pretreatment method for detecting gluten, a food allergen, according to claim 1, is characterized in that, The transient pressure relief phase change cell disruption step specifically includes the following processes: triggering material discharge and generating expansion stress. After receiving the opening pulse command, the high-frequency actuator of the transient pressure relief module drives the valve core to undergo mechanical displacement within a time window of less than 10 milliseconds, performs full-open discharge, and reduces the system pressure at the end of the pressure-bearing metal cavity to the ambient pressure, thus establishing an instantaneous pressure gradient between the discharge end of the pressure-bearing metal cavity and the external atmospheric pressure environment. The volume expansion phase transition process occurs rapidly, generating purely mechanical expansion stress from the inside out. This purely mechanical expansion stress overcomes the yield limit of the polymer backbone, achieving the non-destructive physical release of the gluten protein antigenic epitope without disrupting the folding state of the amino acid sequence of the food allergen gluten protein, and ejecting it in the form of a high-speed jet.

5. The pretreatment method for detecting gluten, a food allergen, according to claim 1, is characterized in that, The coaxial annular atomizing and collecting module has an annular flow equalization cavity inside the annular nozzle body that surrounds the central through hole. The central axis of the liquid inlet is tangent to the inner wall of the annular flow equalization cavity to form a tangential liquid inlet structure. In the cold field construction and in-situ atomization and collection steps, the extraction buffer enters the annular flow equalization cavity at high speed along the tangential direction to form a physical vortex, completing the physical pressure equalization distribution. After pressure equalization, the extraction buffer is sprayed downward at high speed through the annular liquid outlet gap at the lower end, forming a continuous and closed tubular liquid phase water curtain in the space surrounding the discharge port of the linear discharge channel of the transient pressure relief module, enveloping the sprayed solid-gas mixture fluid.

6. The pretreatment method for detecting gluten protein, a food allergen, according to claim 1, is characterized in that, In the aforementioned steps of constructing the cold field and in-situ atomization and collection, the specific physical mechanism by which gas expansion and cooling establish a local low-temperature zone is as follows: The gaseous carbon dioxide undergoes adiabatic expansion towards the low-pressure external environment. During this expansion, it performs work on the outside and absorbs heat energy from within the expansion region, spontaneously causing a temperature drop based on the Joule-Thomson effect. This temperature drop region is used to construct a confined local low-temperature physical space at the geometric center of the coaxial annular atomizing and collecting module. This local low-temperature physical space absorbs residual mechanical frictional heat from the solid-gas mixture, lowering and maintaining the overall temperature of the solid-gas mixture below the temperature threshold for thermal denaturation of gluten, a food allergen.

7. A pretreatment method for detecting gluten, a food allergen, according to claim 1 or 5, characterized in that, The extraction buffer is an extraction buffer containing surfactants, and the specific physical mechanism of in-situ extraction is as follows: The solid-gas mixture acts as a shear flow force, vertically impacting and grazing the inner surface of the tubular liquid phase water curtain. The relative velocity difference between the gaseous carbon dioxide and the extraction buffer generates aerodynamic shear stress at the gas-liquid interface. This aerodynamic shear stress overcomes the surface tension of the extraction buffer, causing the tubular liquid phase water curtain to aerodynamically break apart into micron-sized droplets. The surfactants contained within these micron-sized droplets reduce their surface tension and adhere to the surface of gluten, a food allergen, which undergoes spatial physical collision. This completely encapsulates the exposed gluten and allows for in-situ dissolution and conformational fixation extraction within the internal buffer system of the micron-sized droplets.

8. The pretreatment method for detecting gluten, a food allergen, according to claim 1, is characterized in that, The method synchronously executes multi-sensor coupled feedback control logic based on pressure and torque during the preprocessing stage: The system's main control computer synchronously receives the absolute pressure value from the high-frequency dynamic pressure sensor and the rotational resistance torque value from the dynamic torque sensor with a sampling period of milliseconds. When it is determined that the absolute pressure value has reached the set cell disruption pressure threshold, and at the same time it is determined that the rotational resistance torque value has decreased to within the preset steady-state permeation torque range due to microscopic volume swelling, the system's main control computer synchronously sends two high-level trigger pulse signals through the output interface, which are transmitted to the high-frequency actuator of the transient pressure relief module and the external extractant supply pump without time delay.

9. The pretreatment method for detecting gluten, a food allergen, according to claim 1, is characterized in that, Following the cold field construction and in-situ atomization and collection steps, the process also includes atomization product collection and centrifugation purification steps: The liquid mixture containing gluten, a food allergen, and the accompanying high-speed gaseous carbon dioxide are obtained and enter along the tangential trajectory of the spiral guide groove on the inner wall of the conical collection funnel, generating centrifugal swirling flow. This causes the micron-sized droplets formed by the micro liquid curtain to physically coalesce and converge on the inner wall to form a macroscopic continuous liquid flow. The gaseous carbon dioxide, which has lost its kinetic energy, is discharged into the external environment through the exhaust port. The crude extract at the bottom is collected and transferred to a refrigerated centrifuge to apply a centrifugal force field, and the supernatant is obtained. The supernatant is then injected into a syringe filter equipped with a microporous membrane for pressure filtration to obtain the purified gluten protein extract.

10. A pretreatment system for detecting gluten, a food allergen, using the pretreatment method for detecting gluten, a food allergen, as described in any one of claims 1 to 9, characterized in that... include: The feeding module is used to mix food sample particles with deionized water wetting solution and pump them in. The micro extrusion chamber module includes a pressure-bearing metal cavity with an external temperature-controlled jacket, and a variable-lead extrusion screw coaxially assembled inside the pressure-bearing metal cavity. The supercritical fluid supply module is connected to the inside of the pressure-bearing metal cavity through a high-pressure fluid injection hole on the side wall of the pressure-bearing metal cavity, and is used to pump carbon dioxide into the inside of the pressure-bearing metal cavity; The transient pressure relief module, assembled at the discharge end of the pressure-bearing metal cavity, has an internal linear discharge channel and a high-frequency actuator with a mechanically connected valve core, used to generate expansion stress during discharge; The coaxial annular atomizing and collecting module is installed on the outer geometric periphery of the discharge port of the transient pressure relief module. It has a liquid inlet interface that is connected to an external extractant supply pump. It is used to obtain a liquid mixture containing gluten protein, a food allergen, by relying on the impact of the solid-gas mixture fluid on the extraction buffer to form a micro liquid curtain and by utilizing the local low temperature zone established by the gas expansion and cooling.

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