An in vitro digestion biomimetic degradation test device and control method

Abstract

The present invention discloses an in vitro digestion bionic degradation test device and control method, which combines an in vitro digestion bionic device with a gas metering method, involving a reaction module, a gastric wall-mimicking software drive module, a temperature control module, a condensation module, a gas component analysis module, a gas metering module and a data processing module. In view of the influence of water vapor, pressure and temperature changes accompanying the gas generation process on the metering accuracy, a condensation device is used to eliminate water vapor interference, and a compensation algorithm is used to correct the metering error caused by pressure and temperature changes, thereby realizing real-time and continuous monitoring of the degradation situation during in vitro digestion. The present invention simulates the cooperative extrusion characteristics of rumen peristalsis through the coordinated action of the actuator and the bottom air bag, realizes the full mixing and uniform distribution of gas and liquid in the flexible reactor, ensures the stability of gas production metering within the set metering time period, and thus realizes online precise measurement and real-time data processing and analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of in vitro simulated digestion, and in particular to an in vitro digestion bionic system and a degradation test method thereof. Background Art

[0002] Traditional in vitro degradation testing devices and methods generally use rigid reactors and mechanical stirring during measurement. Mechanical stirring is prone to excessive shear force, and the measurement process does not consider errors caused by multiple factors. For example, Chinese patent CN218491747U discloses a multi-channel rumen liquid in vitro fermentation gas production measurement device, which achieves multi-channel gas production measurement. However, when switching between multiple channels, the gases in each channel easily interfere with each other, and error factors such as water vapor, pressure, temperature, and headspace exhaust gas treatment are not considered.

[0003] Chinese invention patent CN117720994B discloses an in vitro bionic digestion device and proposes the first in vitro bionic reactor for rumen-reticulum interaction. This device uses a soft robot to drive bionic rumen kneading, achieving a high degree of simulation of the ruminant digestion process through bionic structures and multimodal drive control. Chinese invention patent CN117736840B also discloses an in vitro bionic digestion device, control, and degradation testing method. This device integrates real-time monitoring, uses a soft robot to drive the rumen-reticulum interaction, and integrates bionic motion with gas dynamic detection technology to establish a parametric degradation testing method. Existing research lacks a systematic design for the precise measurement of gas production during fermentation and its associated algorithms, making it difficult to effectively reflect the actual overall digestibility of feed by ruminants. Summary of the Invention

[0004] Based on this, it is necessary to address the above problems and propose a technical solution that integrates simulated degradation fermentation and precise gas production measurement. Through an innovative gas measurement system and high-precision dynamic data analysis method, a quantitative evaluation between fermentation gas production rate and feed digestibility is achieved, which makes up for the shortcomings of existing technologies in gas production measurement and digestibility evaluation.

[0005] An in vitro digestion biomimetic degradation testing device comprises: a reaction module, a stomach-wall-mimicking software driver module, a temperature control module, a condensation module, a gas component analysis module, a gas metering module, and a data processing module. The stomach-wall-mimicking software driver module is used to drive the flexible reactor in the reaction module. The temperature control module is installed outside the reaction module and is used to heat the flexible reactor in the reaction module. The condensation module is installed on the exhaust pipe in the reaction module, allowing the gas after dehydration to enter the gas component analysis module and the gas metering module. The gas component analysis module and the gas metering module are connected to the exhaust pipe in the reaction module via a connecting pipe and are located after the condensation module. The gas component analysis module and the gas metering module transmit the measured data to the data processing module to automatically calculate the gas output.

[0006] The reaction module comprises a flexible reactor, an end cover, a feed port and an exhaust port; and the reaction module comprises one or more flexible reactors.

[0007] The gastric wall-mimicking soft drive module includes upper and lower parallel-drive actuators, a bottom airbag, and a connection unit. The flexible reactor is biomimetic driven by periodic inflation and deflation of the bottom airbag and the upper and lower parallel-drive actuators. The connection unit fixes the upper and lower parallel-drive actuators and the bottom airbag on a bracket and closely adheres to the outer wall of the flexible reactor.

[0008] Furthermore, the upper and lower parallel-drive actuators are vertically fixed to the bracket, the bottom airbag is horizontally fixed to the bottom of the bracket, and the reaction module is adapted to be a disposable or reusable component of a flexible reactor and is made of a flexible material;

[0009] The flexible material has the following characteristics: biocompatibility, corrosion resistance, and the ability to maintain stable physical and chemical properties in a simulated rumen digestive environment of ruminants.

[0010] Furthermore, the materials for preparing the flexible reactor, the upper and lower parallel-drive actuators and the bottom airbag include but are not limited to general rubber, silicone and other materials.

[0011] The bottom airbag is composed of an airbag and an air nozzle;

[0012] The bottom airbag is concave and has a deformable curved surface when not inflated. Once inflated, the curved surface becomes nearly flat. The pressure gradient generated by inflation and the deformation of the curved surface enable uniform upward propulsion of materials, adapting to the periodic deformation requirements of the flexible reactor and providing continuous and uniform pressure support.

[0013] A mesh cover is provided on the outside of the flexible reactor to limit its deformation range and prevent structural damage or efficiency reduction due to excessive expansion.

[0014] The gastric wall-mimicking soft body driving module includes one or more upper and lower parallel-driven actuators, which are arranged longitudinally around the flexible reactor, and the bottom airbag is located at the bottom of the flexible reactor; the upper and lower parallel-driven actuators can be divided into upper actuators and lower actuators;

[0015] During the extrusion mixing process, the actuators work in conjunction with the bottom airbag to achieve thorough mixing and uniform distribution of gas and liquid within the flexible reactor. Furthermore, the co-extrusion characteristics, which mimic rumen peristalsis, prevent localized gas accumulation and ensure stable gas production metering.

[0016] Furthermore, the lengths of the upper actuator and the lower actuator can be the same or different. When they are the same, the driving and squeezing effects of the upper and lower actuators on the liquid inside the flexible reactor are similar. As an important improvement, the present application adaptively adjusts the lengths of the upper actuator and the lower actuator according to different materials and the mixing state of the liquid in the flexible reactor, and can provide better mixing effects according to different usage scenario requirements. Specifically, it can be divided into a longer or shorter upper actuator. When the upper actuator is longer, the downward pressure effect on the liquid in the flexible reactor is stronger, and the liquid inside the flexible reactor can be quickly pressed down. It is suitable for liquids with higher viscosity and can promote their mixing. In addition, due to its strong squeezing effect, the intermittent time and detection cycle can be flexibly set according to actual reaction requirements; when the upper actuator is shorter, it can promote the falling of liquid to a certain extent; it is suitable for liquids with lower viscosity. Due to its own strong fluidity, the upper actuator assists the liquid in falling.

[0017] The upper and lower actuators each consist of an array of airbags, each composed of multiple independent airbag units arranged in sequence. The upper and lower actuators are connected end-to-end. The lower actuator and the bottom airbags work together to extrude the material, lifting it and initially mixing it. After release, gravity and the upper actuator's extrusion force help the material return to its original position and further evenly distribute it, achieving asynchronous extrusion of the soft reactor, effectively improving mixing efficiency and uniformity.

[0018] The upper and lower parallel-drive actuators are evenly distributed and fixed on the ring bracket of the ring bracket;

[0019] Furthermore, the upper and lower parallel drive actuators are driven by air pressure, and the bending deformation of the upper and lower parallel drive actuators is controlled to different degrees by dynamically adjusting the air pressure value.

[0020] Furthermore, the working pressure of the upper and lower parallel-driven actuators is tailored to the degree of extrusion required for the reaction, ensuring the accuracy and reliability of the operation and the effective extrusion of the flexible reactor;

[0021] Furthermore, the upper and lower parallel-drive actuators are divided into two parts through different air paths, controlling the upper actuator and the lower actuator respectively, or the entire upper and lower parallel-drive actuators are controlled through one air path;

[0022] Furthermore, when the upper and lower actuators are driven in parallel through two air circuits, the upper and lower actuators can be driven separately with different air pressures, which is suitable for mixing liquids with high viscosity.

[0023] Furthermore, when the upper and lower actuators are controlled by one air circuit, the upper and lower actuators move simultaneously, which is suitable for mixing liquids with low viscosity;

[0024] Furthermore, by simulating the cooperative extrusion characteristics of rumen peristalsis, the bottom airbag and the upper and lower parallel-driven actuators work together to achieve sufficient mixing and uniform distribution of gas and liquid in the flexible reactor, avoiding local accumulation of gas, ensuring the stability of gas production metering and significantly reducing metering errors.

[0025] The constant temperature control unit is used to control the temperature required during the reaction process of the flexible reactor;

[0026] Each reactor has an end cap with a feed port and an exhaust port. The reactor exhaust port is connected to the air inlet of a condensation module via a pipeline. The condensation module can use a Peltier refrigeration device, etc. The condensation device is connected to the exhaust port of the flexible reactor via an air pipe to condense and separate water vapor in the gas.

[0027] The gas component analysis unit is connected to the exhaust port of the condensing device through an air pipe and is used to analyze the gas components in the gas;

[0028] Furthermore, the gas volume measuring unit is connected to the exhaust port of the gas component analysis unit via an air pipe for measuring the gas volume;

[0029] Furthermore, the data collected by the gas component analysis unit and the gas volume measurement unit are transmitted to the data acquisition system, and the data processing system can calculate the data according to the embedded method.

[0030] The gas composition analysis unit monitors CH4 (methane) and CO2 (carbon dioxide) concentrations online in real time. The detected gas flows from the detection unit's outlet to a flow metering unit, where its cumulative volume is measured. Finally, the gas flows from the flow metering unit's exhaust port into a gas collection bag for subsequent collection and analysis.

[0031] The gas metering unit includes a gas flow meter, a pressure and temperature detection device,

[0032] Furthermore, the pressure and temperature detection device in the gas metering unit is used to detect the pressure and temperature of the gas in real time, which facilitates the subsequent accurate measurement and standardized compensation conversion of the gas.

[0033] The data processing module is used to calculate and process data. According to experimental requirements, the gas concentration and volume calculated in each set metering time period are iteratively calculated to obtain the final gas production in real time.

[0034] An in vitro digestion bionic system also includes a corresponding material digestion and degradation control method:

[0035] During the cooperation process between the bottom airbag and the upper and lower parallel-drive actuators, there are four driving states in total. Referring to the peristalsis process of the rumen of ruminants, dynamic conversion from state 1 to state 4 is realized: State 1: the bottom airbag and the upper and lower actuators are not inflated, and the upper and lower actuators remain upright. At this time, the flexible reactor is in a stable and intermittent state, ready for subsequent peristaltic movements; State 2: the bottom airbag is inflated and expanded, and the lower actuator is inflated synchronously to cooperate in squeezing the bottom of the flexible reactor, and the upper actuator remains upright to ensure the stability of the reactor; State 3: the bottom airbag and the lower actuator are deflated, and the upper actuator is inflated. Through pressure distribution adjustment and deformation, the upper area of the flexible reactor is pushed to complete uniform extrusion, thereby realizing stirring and mixing of the material; State 4: the stomach wall-imitation soft drive module stops moving and enters a long period of static state, providing a recovery and preparation stage for the next cycle.

[0036] The dynamic control logic of the driving state is:

[0037] After completing the stabilization preparation, state 1 directly enters state 2; the transition from state 2 to state 3 and from state 3 to state 4 refers to the peristalsis process of the rumen of ruminants. The static time in the peristalsis cycle usually accounts for 60%-80%.

[0038] The inflation and deflation of the actuator are controlled by precision valves, combined with real-time feedback from pressure sensors, to ensure the accuracy and dynamic adaptability of drive state switching, thereby improving the mixing uniformity and peristaltic simulation effect of materials in the flexible reactor.

[0039] After the three driving states are completed, the state 4 intermittent time is entered. The bottom airbag is in normal state, the upper actuator is in normal state, and the lower actuator is in normal state. In state 4, the exhaust port is opened to collect the gas after the reaction. There will be multiple intermittent times in the entire reaction process. By detecting and collecting the cumulative gas volume of multiple stages, the average gas concentration in each stage is calculated to obtain the gas production volume, which is used to evaluate the degradation characteristics of the material.

[0040] The specific control method is as follows: the bottom airbag and the upper and lower parallel actuators sequentially advance from state 1 to state 2 and then to state 3. After reaching the preset pause time, they enter state 3 for the final time, where the upper actuator deflates, followed by a longer pause (state 4) to prepare for the next cycle. The following parameters are also set during the reaction process: the compression strength of the upper and lower parallel actuators can be set to control the pneumatic systems of different upper and lower parallel actuators or the bottom airbags. By applying different air pressures to achieve different degrees of bending and elastic deformation, the maintenance time and switching interval of the above four states are controlled; and the duration of the fermentation cycle is selected based on the real-time gas production.

[0041] When gas metering is performed in each set metering time period, in order to eliminate the influence of water vapor, temperature and pressure on the detection accuracy under different environments, this scheme first removes moisture from the gas by physical condensation, and then the gas passes through the gas component analysis module to obtain the actual methane concentration. Then the gas passes through the gas metering module to measure the volume, and the upper and lower parallel drive actuators and the bottom airbag squeeze the flexible reactor to achieve full mixing and uniform distribution of gas and liquid in the flexible reactor, avoid local accumulation of gas, ensure the stability of gas production metering and significantly reduce metering errors. Finally, the metering errors caused by temperature and pressure factors are calibrated in real time and the detection data are converted to standard conditions online. Relying on the device of the present invention and the proposed degradation test method, the online measurement of gas volume is better realized, and the data is automatically measured and processed, while the accuracy of the data is improved and the consistency and comparability of test data in different environments are guaranteed. Beneficial effects

[0042] An in vitro digestion bionic degradation test device adopts a flexible reaction device and a soft driving module that imitates the stomach wall. Through the cooperation of upper and lower parallel drive actuators and the bottom airbag with the flexible reactor, the gas and liquid in the flexible reactor are fully mixed and evenly distributed, ensuring the stability of gas production metering and significantly reducing metering errors. At the same time, the soft driving force avoids excessive shear force during the stirring process and reduces damage to the microorganisms in the reactor.

[0043] The device and control method of the present invention can monitor the degradation status of the in vitro digestion process in real time, continuously and accurately, realize the online precise measurement of gas and real-time processing and analysis of data, improve the accuracy and data reliability of multiple batches of in vitro digestion simulation experiments, and provide a new solution for the in vitro determination of gas production such as methane and carbon dioxide, carbon metabolism analysis of the digestion process, and ruminant nutrition research.

[0044] The in vitro digestion bionic degradation test device avoids the influence of moisture on metering accuracy. The gas metering method is combined with the device to collect real-time pressure and temperature for standardized compensation of gas volume, and can analyze gas production in real time, unifying the consistency and effectiveness of the generated gas volume and the degradation and digestion of the material after the reaction, and realizing the quantitative evaluation between the fermentation gas production rate and the feed digestibility, making up for the shortcomings of existing technologies in gas production measurement and digestibility evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A comparison diagram of the in vitro bionic digestion steps of the present invention (a is a traditional in vitro digestion simulation step, b is an in vitro digestion simulation step of the present invention);

[0046] Figure 2 This is a schematic diagram of the reaction and stomach wall imitation software driving module of the present invention;

[0047] Figure 3 This is a schematic diagram of the in vitro bionic digestion device of the present invention;

[0048] Figure 4 Schematic diagram of the upper and lower parallel-drive actuators in the stomach wall-mimicking software drive module of the present invention (a is a cross-sectional diagram of two air path controls, b is a diagram of one air path control);

[0049] Figure 5 This is a flowchart of the in vitro biomimetic digestion method of the present invention;

[0050] Figure 6 This is a gas production metering diagram of the in vitro biomimetic digestion of the present invention.

[0051] Description of reference numerals:

[0052] 1 bracket, 2 flexible reactor, 31 feed port, 32 exhaust port, 3 end cover, 4 upper and lower parallel drive actuators, 41 upper actuator, 42 lower actuator, 43 gas path, 44 actuator end, 45 restriction layer, 46 gas inlet, 47 airbag, 48 solid airbag, 5 bottom airbag, 51 reactor base. DETAILED DESCRIPTION

[0053] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0054] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0055] like Figure 1 As shown, the traditional in vitro digestion simulation system uses a rigid reactor and mechanical stirring when conducting in vitro digestion tests, and manually measures the gas production offline through gas chromatography or pressure methods. The manual measurement and calculation process has large human errors, and it is impossible to monitor the metering data in real time. The present invention uses a flexible reactor with a higher degree of bionic restoration. The upper and lower parallel-driven actuators and the bottom airbag cooperate with the flexible reactor to perform bionic peristalsis, thereby achieving full mixing and uniform distribution of gas and liquid in the flexible reactor. In terms of gas metering, it includes gas pretreatment, in-situ online monitoring of components, real-time metering of gas production and data visualization functions. Different from traditional technologies, the present invention realizes automatic real-time monitoring, error calibration and real-time data processing, simplifies the operating steps and improves the metering accuracy.

[0056] like Figure 2 As shown, the present invention discloses an in vitro digestion bionic system and a degradation test method thereof, which includes a reaction module, a stomach wall-mimicking software driving module, a temperature control module, a condensation module, a gas component analysis module, a gas metering module and a data processing module.

[0057] The reaction module contains at least one or more flexible reactors, such as Figure 3 As shown, the bracket 1 can fix the upper and lower parallel drive actuators 4 on the bracket 1 in various ways, including but not limited to bolts, adhesives and other connection methods. The stomach wall imitation soft drive module is used to drive the flexible reactor in the reaction module. The temperature control module adopts a water bath or gas bath heating method and is installed on the outside of the reaction module to heat the flexible reactor in the reaction module. When using a gas bath for heating, the reaction module is placed in a closed environment and heated by heat exchange of the gas. When using a water bath for heating, the reaction module is heated by a water bath jacket. The condensation module is installed on the exhaust pipe in the reaction module to remove the moisture contained in the gas before entering the gas component analysis module and the gas metering module. The gas component analysis module and the gas metering module are connected to the exhaust pipe in the reaction module through a connecting pipe and are installed behind the condensation module. Finally, the gas component analysis module and the gas metering module transmit the data to the data processing module to automatically calculate the gas production.

[0058] Each flexible reactor has an end cap with a feed port 31 and an exhaust port 32. The exhaust port of the flexible reactor is connected via a pipeline to the inlet of a condensation module. The condensation module uses a condenser tube or Peltier refrigeration device to condense and separate water vapor from the gas. The condensed gas is then transported from the outlet of the condensation module to a gas composition analysis unit.

[0059] The end cover 3 is an internal thread structure, which is connected to the external thread of the feed port 31, and is used to fasten the end cover 3 and the flexible reactor 2 to ensure the sealing effect.

[0060] In the gas composition analysis unit, gas concentration sensors monitor CH4 and CO2 concentrations online in real time. The detected gas flows from the outlet of the detection unit to the flow metering unit. Before measuring the gas concentration, the gas passes through pressure and temperature sensors to measure the temperature and pressure at the corresponding moment for subsequent calibration.

[0061] The flow metering unit measures the cumulative volume of gas based on the displacement principle. Finally, the gas enters the gas collection bag from the exhaust port of the flow metering unit for subsequent collection and analysis.

[0062] The gas measurement method adopts the drainage method, but is not limited to the drainage method. The pressure method can also be used for gas measurement in this method.

[0063] The gastric wall-mimicking soft body driving module includes upper and lower parallel-driving actuators, a bottom airbag, and a connecting unit;

[0064] The gastric wall-mimicking soft body driving module includes one or more upper and lower parallel-driven actuators arranged around the middle axis of the flexible reactor. The upper and lower parallel-driven actuators can be divided into an upper actuator 41 and a lower actuator 42.

[0065] The upper and lower actuators each consist of an array of airbags, each composed of multiple independent airbags (47 units) arranged in sequence. The upper and lower actuators are connected end-to-end. After the lower actuator and the bottom airbags complete the extrusion action in coordination, the upper actuator then performs the extrusion, achieving asynchronous extrusion of the soft reactor, effectively improving mixing efficiency and evenly distributing the contents.

[0066] like Figure 4 As shown, there are multiple airbags 47 in the array airbag, and the airbags 47 can be of various shapes and sizes, such as square, round, etc.; a restriction layer 45 is provided on one side of the airbag 47, and the bottom plate is inserted with non-stretchable materials, such as TPU, nylon cloth, etc.; the upper and lower actuators are fixed on the reactor base 51.

[0067] One or more airbags at the end of the array of airbags are filled with solid objects (solid airbags 48), which increase the contact area between the upper and lower actuators and the wall of the flexible reactor, thereby enhancing the squeezing action and weakening the clamping action.

[0068] Furthermore, the upper and lower parallel-drive actuators are evenly distributed and fixed on the bracket;

[0069] Furthermore, the upper and lower parallel-driven actuators are driven by air pressure, and the bending deformation of the upper and lower parallel-driven actuators is controlled to different degrees by dynamically adjusting the air pressure value;

[0070] The upper and lower actuators are controlled separately through separate air paths, or through a single, interconnected air path. Their shape and size are tailored to the desired extrusion effect and the flexible reactor's capacity, ensuring effective control of the flexible reactor. During the extrusion and mixing process, the bottom airbag 5 works in tandem with the upper and lower parallel-driven actuators to ensure thorough mixing of the gas and liquid within the flexible reactor.

[0071] Different air paths can control the upper actuator 41 and the lower actuator 42 separately or together to adapt to application scenarios with different liquid viscosities.

[0072] The upper and lower actuators can be of the same length, or the upper actuator 41 can be longer or shorter than the lower actuator 42; different lengths can achieve different liquid mixing effects. When the upper and lower actuators are the same, the driving and squeezing effects of the liquid inside the flexible reactor are similar. When they are different, the upper actuator can be longer or shorter. When the upper actuator is longer, the downward pressure effect on the liquid in the flexible reactor is stronger, and the liquid inside the flexible reactor can be quickly pressed down. When the upper actuator is shorter, it can promote the liquid to fall to a certain extent.

[0073] The upper and lower parallel actuators 4 are provided with frictional features on their contact surfaces with the object. These features may feature any one of a grid, herringbone, or stripe pattern, or a combination thereof. This frictional feature increases friction between the upper and lower parallel actuators and the flexible reactor 2, preventing problems such as deformation and insufficient extrusion caused by sliding and arching during operation.

[0074] During installation, the bottom airbag 5 is located at the bottom of the flexible reactor 2. When no gas is filled in, the airbag is a concave structure, which plays a certain supporting role on the bottom of the flexible reactor 2. An air pipe joint is installed on the reactor base 51. One end of the air pipe joint is located on the outside of the reactor base 51. The air inlet 46 is connected to the pneumatic system. The other end of the air pipe joint passes through the reactor base 51 and extends into the airbag 47. When the pneumatic system inflates it, the air pressure in the airbag 47 increases, causing the middle concave part to push upward, corresponding to the upward movement of the liquid in the flexible reactor.

[0075] The bottom airbag 5 and upper and lower parallel actuators 4 are driven by air pressure. Precisely adjusting the air pressure allows precise control of the extrusion force on the flexible reactor 2. The operating air pressure of the actuators is tailored to the required extrusion strength, ensuring precise and reliable operation. Multiple upper and lower parallel actuators are evenly distributed and fixed to the bracket 1. They are connected in series via air circuit 43 for simultaneous control, achieving simultaneous inward extrusion.

[0076] The flexible reactor 2 can be made of polyethylene (PE) film, low-density polyethylene (LDPE) film, ultra-low-density polyethylene (LLDPE) film, polypropylene (PP) film, polyvinyl chloride (PVC) film, polyethylene terephthalate (PET) film, polystyrene (PS) film, ethylene / vinyl acetate (EVA) film, polyamide (PA) film and the like.

[0077] like Figure 5 As shown, a control method for an in vitro digestion bionic system:

[0078] During the cooperation process between the bottom airbag and the upper and lower parallel-drive actuators, there are four driving states in total. Referring to the peristalsis process of the rumen of ruminants, dynamic conversion from state 1 to state 4 is realized: State 1: the bottom airbag and the upper and lower actuators are not inflated, and the upper and lower actuators remain upright. At this time, the flexible reactor is in a stable and intermittent state, ready for subsequent peristaltic movements; State 2: the bottom airbag is inflated and expanded, and the lower actuator is inflated synchronously to cooperate in squeezing the bottom of the flexible reactor, and the upper actuator remains upright to ensure the stability of the reactor; State 3: the bottom airbag and the lower actuator are deflated, and the upper actuator is inflated. Through pressure distribution adjustment and deformation, the upper area of the flexible reactor is pushed to complete uniform extrusion, thereby realizing stirring and mixing of the material; State 4: the stomach wall-imitation soft drive module stops moving and enters a long period of static state, providing a recovery and preparation stage for the next cycle.

[0079] The dynamic control logic of the driving state is:

[0080] After completing the stabilization preparation, state 1 directly enters state 2; the transition from state 2 to state 3 and from state 3 to state 4 refers to the peristalsis process of the rumen of ruminants. The static time in the peristalsis cycle usually accounts for 60%-80%.

[0081] The inflation and deflation of the actuator are controlled by precision valves, combined with real-time feedback from pressure sensors, to ensure the accuracy and dynamic adaptability of drive state switching, thereby improving the mixing uniformity and peristaltic simulation effect of materials in the flexible reactor.

[0082] After the three driving states are completed, the state 4 intermittent time is entered. The bottom airbag is in normal state, the upper actuator is in normal state, and the lower actuator is in normal state. In state 4, the exhaust port is opened to collect the gas after the reaction. There will be multiple intermittent times in the entire reaction process. By detecting and collecting the cumulative gas volume of multiple stages, the average gas concentration in each stage is calculated to obtain the gas production volume, which is used to evaluate the degradation characteristics of the material.

[0083] The specific control method is as follows: the bottom airbag and the upper and lower parallel actuators sequentially advance from state 1 to state 2 and then to state 3. After reaching the preset pause time, they enter state 3 for the final time, where the upper actuator deflates, followed by a longer pause (state 4) to prepare for the next cycle. The following parameters are also set during the reaction process: the compression strength of the upper and lower parallel actuators can be set to control the pneumatic systems of different upper and lower parallel actuators or the bottom airbags. By applying different air pressures to achieve different degrees of bending and elastic deformation, the maintenance time and switching interval of the above four states are controlled; and the duration of the fermentation cycle is selected based on the real-time gas production.

[0084] When gas metering is performed in each set metering time period, in order to eliminate the influence of water vapor, temperature and pressure on the detection accuracy under different environments, this scheme first removes moisture from the gas by physical condensation, and then the gas passes through the gas component analysis module to obtain the actual methane concentration. Then the gas passes through the gas metering module to measure the volume, and the upper and lower parallel drive actuators and the bottom airbag squeeze the flexible reactor to achieve full mixing and uniform distribution of gas and liquid in the flexible reactor, avoid local accumulation of gas, ensure the stability of gas production metering and significantly reduce metering errors. Finally, the metering errors caused by temperature and pressure factors are calibrated in real time and the detection data are converted to standard conditions online. Relying on the device of the present invention and the proposed degradation test method, the online measurement of gas volume is better realized, and the data is automatically measured and processed, while the accuracy of the data is improved and the consistency and comparability of test data in different environments are guaranteed.

[0085] Table 1 Control method table

[0086]

[0087] in:

[0088] After state 2, the liquid in the flexible reactor 2 is squeezed to the upper region of the flexible reactor 2;

[0089] After state 3, the liquid in the flexible reactor 2 returns to the bottom area of the flexible reactor 2;

[0090] The entire process consists of switching between state 1, state 2, state 3 and state 4. The number of cycles and the interval time can be set according to actual conditions to ensure mixing efficiency while creating a comfortable and balanced environment for microorganisms.

[0091] In this example, a degradability test method for in vitro digestion simulation is provided. The process mainly includes the following steps:

[0092] S1: Instrument and material preparation

[0093] Prepare a carbon dioxide gas cylinder, a deoxidizing copper column, a constant temperature incubator, a liquid separator, a stirring device, gauze, a funnel, a glass incubator, an analytical balance, a stoppered glass bottle, a thermos flask, and a gas metering device.

[0094] S2: Preparation of artificial rumen buffer solution

[0095] The artificial rumen buffer solution is prepared as shown in Table 1. The artificial saliva preparation method proposed in this invention comprises macronutrients, trace elements, a buffer solution, a reducing solution, and functional additives. This improves rumen fermentation efficiency by supplementing trace elements and enhancing pH stability. Mix the following ingredients in the following proportions: 400 mL of distilled water + 0.1 mL of trace element solution + 200 mL of buffer solution + 200 mL of macronutrient solution + 1 mL of resazurin solution. Place the mixture in a stoppered glass bottle. Add CO2 until the solution is saturated. Preheat the bottle to 39°C in a thermostat until ready for use. Before use, add 40 mL of reducing agent solution until the solution turns from blue to nearly colorless.

[0096] Table 2 Artificial rumen buffer formula

[0097]

[0098] S3: Collection of rumen fluid

[0099] Rumen fluid was collected from three healthy, rumen-cannulated cows and immediately placed in a thermos to keep warm to prevent changes in the microbial community.

[0100] S4: Preparation of samples to be tested

[0101] Weigh 0.4 g of the sample (feed) to be tested, place it in a 200 mL glass culture container, and preheat it in a 39°C constant temperature incubator for 30-60 minutes.

[0102] S5: Preparation of culture medium

[0103] The artificial rumen buffer solution and rumen fluid were mixed in a ratio of 2:1 to prepare a culture medium.

[0104] S6: Sample loading and incubation

[0105] Load the sample and culture medium into the flexible reactor. Add 60 mL of culture medium to the preheated flexible reactor, purging it with an inert gas such as N2 to maintain an anaerobic environment. The reactor is then quickly sealed and placed in a thermostat at 39°C for in vitro culture for 72 hours. Set the extrusion interval between the upper and lower parallel actuators 4 and the bottom airbag 5.

[0106] S7: Biogas metering

[0107] During the culture process, the exhaust port 32 is always open, and the metering time period and the interval between the upper and lower parallel actuators 4 and the bottom airbag 5 squeezing the outer wall of the flexible reactor 2 are set according to the experimental requirements. The biogas generated is discharged from the flexible reactor through the cooperative squeezing action of the upper and lower parallel actuators 4 and the bottom airbag 5, and the water vapor in the gas is eliminated by the condensation device. The dried gas is then passed through the gas concentration metering device to measure the gas concentration C within the set metering time period. i , and then the gas volume metering device records the amount of gas discharged this time V i .

[0108] S8: Data Calculation

[0109] There are four driving states in the coordinated control process of the bottom airbag 5 and the upper and lower parallel-drive actuators 4. State 1 is the bottom airbag inflation, the upper actuator is normal, and the lower actuator is normal; State 2 is the bottom airbag inflation, the upper actuator is normal, and the lower actuator is inflated; State 3 is the bottom airbag deflation, the upper actuator is inflated, and the lower actuator is normal. After the three driving states are completed, state 4 (interval time) is entered. Data is measured in real time in each state. After the gas passes through the condensation module to remove water vapor, the dry gas enters the gas component analysis module to obtain the average C within the set metering time period. i The value is then obtained through the gas metering module to obtain V i Value, the volume of methane gas V in the biogas at time i CH4i calculate:

[0110] ,

[0111] Where,

[0112] V CH4i is the volume of methane gas discharged from biogas during the i-th time; C i V is the concentration of methane gas in the biogas discharged during the i-th time; i is the volume of biogas discharged during the i-th time;

[0113] After the condensed dry gas passes through the pressure and temperature sensors to record real-time data, the data processing module performs subsequent error calibration and standard condition conversion;

[0114] Compensation conversion under standard conditions: In order to achieve temperature, pressure compensation and water vapor compensation, the detected values will be converted into dry gas values under standard conditions, using the following formula for calculation:

[0115] ,

[0116] Where,

[0117] is the volume of methane gas discharged from the biogas under standard conditions during the i-th time period; To take temperature and volume into account; is the volume of methane gas discharged from biogas during the i-th time;

[0118] Temperature and pressure compensation algorithm: The ideal gas law is used to calculate the temperature and pressure factors ( ) can be calculated according to the following formula:

[0119] ,

[0120] Where,

[0121] T S and P S : Standard temperature and standard pressure;

[0122] T gas and P gas : Indicates the temperature and pressure of the gas in the gas metering device when the flexible reactor produces gas; t and p: Indicates the temperature and pressure of the surrounding environment at that time, which can be obtained from the built-in temperature and pressure sensors, and the data will be automatically updated every time the gas metering device finishes measuring;

[0123] Calculate the proportional coefficient of error caused by factors such as temperature and pressure The actual gas production can be obtained by multiplying the gas production measurement result by the proportional coefficient.

[0124] In the data processing module, the cumulative methane gas volume V of each set metering time period is analyzed and calculated. Ai :

[0125] ,

[0126] Where V Ai V is the cumulative volume of methane produced during time i; Ai-1 V is the cumulative volume of methane produced during time i-1; CH4i is the volume of methane gas discharged from the biogas during the i-th time.

[0127] The flexible reactor of the device of the present invention achieves sufficient mixing and uniform distribution of gas and liquid in the flexible reactor due to the coordinated control of the upper and lower parallel-driven actuators and the bottom airbag, avoids local accumulation of gas, ensures the stability of gas production metering and significantly reduces metering errors, and can directly calculate the actual methane production in each set metering time period in real time, and can discharge all the gas in the headspace of the flexible reactor to achieve accurate measurement of the headspace gas concentration and volume, comprehensively collect all the discharged gas in the gas collection bag, and accurately measure the methane concentration and related gas volume in the headspace and exhaust, and can accurately determine the cumulative methane production.

[0128] The single cumulative methane production is calculated as follows:

[0129] ,

[0130] Where,

[0131] is the cumulative methane production (mL); is the headspace volume in the reaction bottle (mL); The total volume of gas in the gas bag (or the total volume of gas produced recorded by other gas measuring devices) at the end of fermentation (mL); is the methane concentration at the end of fermentation (L / L, %); The proportional coefficient of error caused by factors such as temperature and pressure; For the above The calculated cumulative methane volume, This is the value measured by the methane concentration sensor;

[0132] The methane concentration and volume of each set metering time period are summarized in the data processing module, and the methane production of each set metering time period is calculated. The cumulative methane volume produced is finally obtained as:

[0133]

[0134] Where,

[0135] is the final cumulative methane production (mL), is the concentration of methane gas in the biogas discharged within i time, is the cumulative volume of methane produced during time i, Consider the factors of temperature and volume within i time.

[0136] The device of the present invention cooperates with the degradation test method to remove water vapor in the produced gas through a condensation device during the metering process, eliminating the influence of water vapor. At the same time, through each extrusion and discharge cycle, the gas and liquid in the flexible reactor are fully mixed and evenly distributed, avoiding local accumulation of gas, ensuring the stability of gas production metering and significantly reducing metering errors, and achieving accurate metering of the gas production volume in each set metering time period, thereby improving the accuracy and rationality of gas production metering during the entire in vitro digestion process. At the same time, in each set metering time period, real-time pressure and temperature are collected for standardized compensation of gas volume, unifying the consistency and effectiveness of gas volume generated under different environmental conditions, achieving quantitative evaluation between fermentation gas production rate and feed digestibility, and making up for the shortcomings of existing technologies in gas production measurement and digestibility evaluation.

[0137] Each experiment was repeated at least 3 times and at least 3 blank control groups were set up.

[0138] A material was subjected to an in vitro digestion biomimetic degradation test using the device and control method proposed in this invention. The gas production calculation results are as follows: Figure 6 As shown, the methane production tends to be stable after 48 hours as time goes by, and the degradation is basically completed. The device proposed in the present invention and the corresponding degradation and digestion method accurately carry out the digestion and degradation evaluation.

[0139] It should be noted that the present invention proposes an in vitro digestion simulation degradation test method. The reaction module is only used to provide a degradation environment container and is not limited to a flexible reactor. A rigid reactor combined with a traditional stirring method is also applicable to the degradation test method proposed in the present invention. The temperature control module is used to maintain a suitable ambient temperature and is not limited to water bath temperature control. A gas bath heating method is also applicable to this method. The gas metering module includes but is not limited to the drainage method used in the present invention, and can also use a pressure method for measurement.

[0140] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0141] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. An in vitro digestion biomimetic degradation test device, characterized in that: include: Reaction module, stomach wall simulation software drive module, temperature control module, condensation module, gas component analysis module, gas metering module and data processing module; The reaction module is located inside the temperature control module, the stomach wall-mimicking software driving module is connected to the middle and bottom of the reaction module, one end of the condensation module is connected to the upper part of the reaction module, and the other end is connected to the gas component analysis module and the gas metering module in sequence, and the gas component analysis module and the gas metering module transmit the measurement data to the data processing module to automatically calculate the gas production; The bionic driving module of the gastric wall-mimicking soft body includes upper and lower parallel-drive actuators, a bottom airbag, and a connection unit; the bionic driving of the flexible reactor is achieved through periodic inflation and deflation of the bottom airbag and the upper and lower parallel-drive actuators; The stomach wall-mimicking soft body driving module includes one or more upper and lower parallel-driving actuators arranged around the middle of the flexible reactor, and the bottom airbag is located at the bottom of the flexible reactor; The upper and lower parallel-drive actuators include an upper actuator and a lower actuator that are independent of each other. During the extrusion and mixing process, the above actuators work in conjunction with the bottom airbag; The upper actuator and the lower actuator are each composed of a section of array airbags, each section of the array airbag is composed of multiple independent airbag units arranged in sequence, the upper and lower actuators are connected in a tail-to-tail manner, and one or more airbags at the end of the array airbag are filled into a solid; the lengths of the upper actuator and the lower actuator can be the same or different.

2. The device according to claim 1, characterized in that The reaction module comprises a flexible reactor, an end cover, a feed port and an exhaust port; and the reaction module comprises one or more flexible reactors.

3. The device according to claim 1, characterized in that The flexible reactor is a disposable or reusable component and is made of flexible materials.

4. The device according to claim 1, characterized in that The bottom airbag is concave and has a deformable arc surface when not inflated. After inflation, the arc surface is almost flat. The pressure gradient generated by inflation and the deformation of the arc surface can achieve uniform upward propulsion of the material, adapt to the periodic deformation requirements of the flexible reactor, and provide continuous and uniform pressure support.

5. The device according to claim 1, characterized in that The connecting unit is used to fix the upper and lower parallel-drive actuators and the bottom airbag on the bracket, and is used to massage the outer wall of the flexible reactor and transmit external force to promote the mixing and uniform distribution of the internal materials; A mesh cover is provided on the outside of the flexible reactor to limit its deformation range and prevent structural damage or efficiency reduction due to excessive expansion.

6. A control method for the device according to any one of claims 1 to 5, characterized in that: During the cooperation between the bottom airbag and the upper and lower parallel-drive actuators, there are four driving states. With reference to the rumen peristalsis process of ruminants, dynamic conversion from state 1 to state 4 is achieved: State 1: The bottom airbag and the upper and lower actuators are not inflated, and the upper and lower actuators remain upright. At this time, the flexible reactor is in a stable and intermittent state, ready for subsequent peristaltic motion; State 2: The bottom airbag is inflated and expanded, and the lower actuator is inflated synchronously, cooperatively squeezing the bottom of the flexible reactor, while the upper actuator remains upright to ensure the stability of the reactor; State 3: The bottom airbag and the lower actuator are deflated, and the upper actuator is inflated. Through pressure distribution adjustment and deformation, the upper area of the flexible reactor is pushed to complete uniform extrusion, achieving stirring and mixing of the materials; State 4: The gastric wall-simulating software driver module stops moving and enters a long period of rest, providing a recovery and preparation phase for the next cycle; The dynamic control logic of the driving state is: After state 1 completes stable preparation, it directly enters state 2; The transition from state 2 to state 3 and from state 3 to state 4 refers to the rumen peristalsis process of ruminants, and the static time accounts for 60%-80% of the peristalsis cycle; The inflation and deflation of the actuator are controlled by precision valves, combined with real-time feedback from pressure sensors, to ensure the accuracy and dynamic adaptability of drive state switching, thereby improving the mixing uniformity and peristaltic simulation effect of materials in the flexible reactor.

7. The method according to claim 6, characterized in that After the gas passes through the condensation module to remove water vapor, the dry gas enters the gas component analysis module to obtain the average C i The value is then obtained through the gas metering module to obtain V i Value, the volume of methane gas V in the biogas at time i CH4i calculate: ， Where, V CH4i is the volume of methane gas discharged from biogas during the i-th time; C i is the concentration of methane gas in the biogas discharged during the i-th time; V i is the volume of biogas discharged during the i-th time; After the condensed dry gas passes through the pressure and temperature sensors to record real-time data, the data processing module performs subsequent error calibration and standard condition conversion; Compensation conversion under standard conditions: In order to achieve temperature, pressure compensation and water vapor compensation, the measured values are converted into dry gas values under standard conditions and calculated using the following formula: ， Where, is the volume of methane gas discharged from the biogas under standard conditions during the i-th time period; To take temperature and volume into account; is the volume of methane gas discharged from biogas during the i-th time; Temperature and pressure compensation algorithm: The ideal gas law is used to calculate the temperature and pressure factors ( ) can be calculated according to the following formula: ， Where, T S and P S : Standard temperature and standard pressure; T gas and P gas : Indicates the temperature and pressure of the gas in the gas metering device when the flexible reactor produces gas; t and p: Indicates the temperature and pressure of the surrounding environment at that time, which can be obtained from the built-in temperature and pressure sensors, and the data will be automatically updated every time the gas metering device finishes measuring; Calculate the proportionality coefficient of the error caused by temperature and pressure factors The actual gas production is calculated by multiplying the gas production measurement result by the proportional coefficient. In the data processing module, the cumulative methane gas volume V of each set metering time period is analyzed and calculated. Ai : ， Where, V Ai V is the cumulative volume of methane produced during time i; Ai-1 V is the cumulative volume of methane produced during time i-1; CH4i is the volume of methane gas discharged from the biogas during the i-th time.

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