Meat product freshness detection method and device

Abstract

The invention provides a meat product freshness detection method and device. The method comprises the following steps: placing a hydrogel fluorescent electrode in a detection area of a to-be-detected meat product; irradiating the hydrogel fluorescent electrode with light with a preset wavelength, and obtaining temperature and humidity in the detection area of the to-be-detected meat product; acquiring the intensity of an optical signal reflected by the hydrogel fluorescent electrode; obtaining the freshness of the to-be-detected meat product based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of the to-be-detected meat product; wherein the hydrogel fluorescent electrode comprises halloysite and a nitrogen-doped graphene quantum dot composite nanomaterial, and the hydrogel fluorescent electrode has different absorption intensities for light with a preset wavelength in volatile basic nitrogen with different concentrations under the irradiation of the light with the preset wavelength. The in-situ, nondestructive and real-time detection of the freshness of the meat product can be realized, and the detection efficiency and the detection accuracy of the freshness of the meat product are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural and livestock product quality detection, and in particular to a meat product freshness detection method and device. Background Art

[0002] Meat freshness refers to its ability to maintain its original quality during processing, storage, transportation, and sales. Accurately testing meat freshness is crucial for ensuring food safety, protecting consumer health, improving product quality and market competitiveness, optimizing supply chain management, and promoting industry standardization and technological advancement.

[0003] Traditional physical and chemical analysis can be used to determine the freshness of meat products. These methods typically require specific instruments and equipment to test indicators such as pH and total volatile basic nitrogen (TVB-N) content, and then determine the freshness of the meat based on these indicators. While these methods provide a more objective measure of meat freshness, they require high operator skill, are complex and tedious, and are therefore inefficient for meat freshness testing.

[0004] In addition, traditional physical and chemical analysis methods usually need to be carried out in laboratories and cannot conduct real-time detection of the freshness of meat products during transportation, storage and sales.

[0005] Therefore, how to improve the detection efficiency of meat product freshness and realize real-time non-destructive detection of meat product freshness is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0006] The present invention provides a meat product freshness detection method and device, which are used to solve the defects of the existing technology that the detection efficiency of meat product freshness is low and it is difficult to realize real-time non-destructive detection of meat product freshness, thereby improving the detection efficiency of meat product freshness and realizing real-time non-destructive detection of meat product freshness.

[0007] The present invention provides a method for detecting the freshness of meat products, comprising the following steps.

[0008] placing the hydrogel fluorescent electrode in the detection area of ​​the meat product to be tested; irradiating the hydrogel fluorescent electrode with light of a preset wavelength and obtaining the temperature and humidity within the detection area of ​​the meat product to be tested; Obtaining the intensity of the light signal reflected by the hydrogel fluorescent electrode; Obtaining the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of ​​the meat product to be tested; The hydrogel fluorescent electrode comprises a composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots. When irradiated with light of the preset wavelength, the hydrogel fluorescent electrode has different absorption intensities for light of the preset wavelength in different concentrations of volatile basic nitrogen.

[0009] According to a meat product freshness detection method provided by the present invention, the composite nanomaterial is prepared based on the following steps: acidifying the halloysite powder to obtain acidified halloysite powder; mixing the acidified halloysite powder with a solution containing nitrogen-doped graphene quantum dots; The mixed solution of the acidified halloysite powder and the nitrogen-doped graphene quantum dots is subjected to vacuum freeze-drying treatment to obtain the composite nanomaterial.

[0010] According to a meat product freshness detection method provided by the present invention, the mass ratio of the acidified halloysite powder to the solution containing nitrogen-doped graphene quantum dots is 1:8.

[0011] According to a meat product freshness detection method provided by the present invention, the hydrogel fluorescent electrode is prepared based on the following steps: mixing the composite nanomaterial with a polyvinyl alcohol colloidal solution; A mixed solution of the composite nanomaterial and the polyvinyl alcohol colloid solution is poured into a mold and subjected to repeated freeze-thaw treatment to obtain the hydrogel fluorescent electrode.

[0012] According to a meat product freshness detection method provided by the present invention, the polyvinyl alcohol colloid solution is prepared based on the following steps: Adding polyvinyl alcohol particles to deionized water to prepare a polyvinyl alcohol solution; After the polyvinyl alcohol solution is allowed to stand at room temperature for a first preset time, the polyvinyl alcohol solution is stirred at a preset temperature for a second preset time; The polyvinyl alcohol solution is cooled to room temperature to obtain the polyvinyl alcohol colloid solution.

[0013] According to a meat product freshness detection method provided by the present invention, the preset wavelength has a value range of 360 nm to 380 nm.

[0014] According to a meat product freshness detection method provided by the present invention, obtaining the intensity of the light signal reflected by the hydrogel fluorescent electrode includes: The intensity of the light signal of a specific wavelength reflected by the hydrogel fluorescent electrode is obtained.

[0015] According to a meat product freshness detection method provided by the present invention, the freshness of the meat product to be detected is obtained based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of ​​the meat product to be detected, including: Obtaining the volatile basic nitrogen concentration of the environment where the hydrogel fluorescent electrode is located based on the intensity of the light signal reflected by the hydrogel fluorescent electrode; The freshness of the meat product to be tested is obtained based on the volatile basic nitrogen concentration of the environment where the hydrogel fluorescent electrode is located and the temperature and humidity in the detection area of ​​the meat product to be tested.

[0016] The present invention also provides a meat product freshness detection device for implementing any of the meat product freshness detection methods described above, comprising an excitation light source module, a hydrogel fluorescent electrode, a fluorescence detection module, a temperature and humidity detection module, and a processor; the hydrogel fluorescent electrode comprises a composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots, and the hydrogel fluorescent electrode, under irradiation with light of the preset wavelength, has different absorption intensities for light of the preset wavelength in different concentrations of volatile basic nitrogen; The excitation light source module is used to emit light of the preset wavelength to illuminate the hydrogel fluorescent electrode; The fluorescence detection module is used to collect the light signal reflected by the hydrogel fluorescent electrode, and convert the collected light signal into a voltage value and then send it to the processor; The temperature and humidity detection module is used to collect the temperature and humidity in the detection area of ​​the meat product to be tested, and send the collected temperature and humidity in the detection area of ​​the meat product to be tested to the processor; The processor is used to obtain the intensity of the light signal reflected by the hydrogel fluorescent electrode based on the received voltage value, and then obtain the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of ​​the meat product to be tested.

[0017] A meat product freshness detection device according to the present invention further includes: a filter; The filter is arranged between the hydrogel fluorescent electrodes and is used for filtering the light signal reflected by the hydrogel fluorescent electrodes.

[0018] The meat product freshness detection method and device provided by the present invention utilize the specific response characteristics of the hydrogel fluorescent electrode to volatile basic nitrogen. After placing the hydrogel fluorescent electrode in the detection area of ​​the meat product to be tested, the hydrogel fluorescent electrode is irradiated with light of a preset wavelength, and the intensity of the light signal reflected by the hydrogel fluorescent electrode is detected. Combined with the ambient temperature and humidity in the detection area of ​​the meat product to be tested, the freshness of the meat product to be tested can be detected in situ, non-destructively and in real time, which significantly improves the detection efficiency and accuracy of the freshness of the meat product. The detection process does not require complex instruments and professional operators, and can be directly applied to various scenarios such as meat product transportation, warehousing and sales, breaking through the time and space limitations of laboratory testing. Through multi-parameter coupling analysis, the accuracy of the meat product freshness detection results is significantly improved, and a lightweight freshness detection solution that can be integrated into smart packaging can be provided for the entire meat product industry chain. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is one of the flow charts of the meat product freshness detection method provided by the present invention.

[0021] Figure 2 This is one of the structural schematic diagrams of the meat product freshness detection device provided by the present invention.

[0022] Figure 3 It is a schematic diagram of the principle of the meat product freshness detection method provided by the present invention.

[0023] Figure 4 It is a fluorescence spectrum diagram of the test mixed solution in the meat product freshness detection method provided by the present invention in an environment of ammonia with different concentrations.

[0024] Figure 5 This is a fluorescence intensity calibration diagram of a test mixed solution in the meat product freshness detection method provided by the present invention.

[0025] Figure 6 It is a schematic diagram of the selectivity of the hydrogel fluorescent electrode in the meat product freshness detection method provided by the present invention.

[0026] Figure 7 It is a schematic diagram of the stability of the hydrogel fluorescent electrode in the meat product freshness detection method provided by the present invention.

[0027] Figure 8 It is a schematic diagram of the repeatability of the hydrogel fluorescent electrode in the meat product freshness detection method provided by the present invention.

[0028] Figure 9 This is a physical picture of the purple high-power light-emitting diode in the meat product freshness detection device provided by the present invention.

[0029] Figure 10 A physical diagram of the timing cycle submodule in the meat product freshness detection device provided by the present invention.

[0030] Figure 11 It is a schematic diagram of the principle of the timing cycle submodule in the meat product freshness detection device provided by the present invention.

[0031] Figure 12 A physical picture of the processor in the meat product freshness detection device provided by the present invention.

[0032] Figure 13 It is a schematic diagram of the principle of the processor in the meat product freshness detection device provided by the present invention.

[0033] Figure 14 It is a schematic diagram of the principle of the fluorescence detection module in the meat product freshness detection device provided by the present invention.

[0034] Figure 15 It is a schematic diagram of the principle of the temperature and humidity detection module in the meat product freshness detection device provided by the present invention.

[0035] Figure 16 This is the second structural diagram of the meat product freshness detection device provided by the present invention.

[0036] Figure 17 This is a program flow chart of the meat product freshness detection device provided by the present invention.

[0037] Figure 18 It is a fitting curve of the intensity of the light signal reflected by the hydrogel fluorescent electrode detected by the fluorescence detection module of the meat product freshness detection device provided by the present invention under different storage conditions and the content of volatile basic nitrogen generated by the meat product to be tested. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0039] In the description of the invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0040] In the description of this application, the terms "first", "second", etc. are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of the same type, and do not limit the number of objects. For example, the first object can be one or more. In addition, in the description of this application, "and / or" represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0041] It should be noted that the meat products in the present invention may include but are not limited to fresh pork, fresh beef, fresh mutton, fresh chicken and fresh duck.

[0042] Sensory evaluation is a technique used in related technologies to determine the freshness of meat products. This method uses the five senses to subjectively assess the color, smell, texture, and appearance of meat products to determine their freshness. While simple and easy to use, it can quickly determine the freshness of meat products without the need for complex equipment. However, sensory evaluation is susceptible to subjective evaluators, making it difficult to objectively and accurately determine the freshness of meat products.

[0043] In related technologies, the freshness of meat products can also be determined through traditional physical and chemical analysis methods. Traditional physical and chemical analysis methods generally require specific instruments and equipment to test indicators such as the pH value and total volatile basic nitrogen (TVB-N) content of meat products, and then determine the freshness of meat products based on these indicators.

[0044] Total Volatile Basic Nitrogen (TVB-N) is a key indicator for evaluating the quality and freshness of meat products. TVB-N is composed of ammonia and other nitrogen compounds and is typically produced by the degradation of amino acids and proteins during storage and processing. TVB-N provides valuable data for evaluating the freshness and quality of meat products.

[0045] The freshness of the meat product detected based on the physicochemical analysis method is relatively objective, but the technical requirements for the operator are relatively high, the experimental steps are complex, the operation is cumbersome, a large amount of time cost and labor cost need to be invested, and the efficiency of the meat product freshness detection is relatively low.

[0046] In the traditional physicochemical analysis method, sampling and processing of the meat product are usually required, which can damage the integrity of the meat product, and is not suitable for commercial meat products that need to maintain integrity. Moreover, the sampling and processing of the meat product can cause damage to the meat product.

[0047] The traditional physicochemical analysis method usually needs to be carried out in a laboratory, and cannot be used for real-time detection of the freshness of the meat product during transportation, storage and sales of the meat product.

[0048] Therefore, the traditional meat product freshness detection method cannot objectively, accurately and efficiently detect the freshness of the meat product in real time and non-destructively. How to more objectively, accurately and efficiently detect the freshness of the meat product in real time and non-destructively is a technical problem to be solved in the field.

[0049] To this end, the present application provides a meat product freshness detection method and device. The meat product freshness detection method and device provided by the present application researches a nano-composite material having specific response to volatile basic nitrogen generated in the spoilage process of the meat product, creates a portable meat product freshness detection device, uses the specific response of the volatile basic nitrogen to the hydrogel fluorescent electrode including the nano-composite material to cause the change of the fluorescence intensity of the hydrogel fluorescent electrode, processes the detection result by the processor, displays the detection result on the display device, synchronously displays and stores the data by the mobile phone app and the upper computer, and realizes the real-time and non-destructive detection of the freshness of the meat product.

[0050] The meat product freshness detection method and device provided by the present application will be described below. Figures 1-18 The meat product freshness detection method and device provided by the present application will be described below.

[0051] Figure 1 is one of the flowcharts of the meat product freshness detection method provided by the present application, as Figure 1 shown, the method comprises the following steps: step 101, placing a hydrogel fluorescent electrode in a detection area of a meat product to be detected.

[0052] The hydrogel fluorescent electrode comprises a composite nano-material of halloysite and nitrogen-doped graphene quantum dots, and the absorption intensity of the hydrogel fluorescent electrode to the preset wavelength of light is different in different concentrations of volatile basic nitrogen under the irradiation of the preset wavelength of light.

[0053] It should be noted that the meat product freshness detection method provided by the present invention can be implemented using a meat product freshness detection device. Figure 2 This is one of the structural diagrams of the meat product freshness detection device provided by the present invention. Figure 2 As shown, the meat product freshness detection device 201 may include but is not limited to a hydrogel fluorescent electrode 202 , an excitation light source module 203 , a fluorescence detection module 204 , a temperature and humidity detection module 205 and a processor 206 .

[0054] Specifically, the meat product to be tested is the detection object of the meat product freshness detection method provided by the present invention. Based on the meat product freshness detection method provided by the present invention, the meat product to be tested can be subjected to real-time non-destructive detection.

[0055] It should be noted that the meat product to be tested in the embodiment of the present invention can be fresh pork, fresh beef, fresh mutton or fresh poultry, etc. The meat product to be tested in the embodiment of the present invention can be determined based on actual needs. The meat product to be tested in the embodiment of the present invention is not specifically limited.

[0056] It should be noted that during the spoilage process of fresh meat products, protein decomposition will produce volatile basic nitrogen (such as ammonia, trimethylamine and dimethylamine, etc.). The concentration of the above volatile basic nitrogen will increase significantly with the degree of spoilage of fresh meat products.

[0057] The hydrogel fluorescent electrode 202 in the embodiment of the present invention, when irradiated with light of a predetermined wavelength, exhibits varying absorption intensities for light of the predetermined wavelength in different concentrations of volatile basic nitrogen. Therefore, the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 in different concentrations of volatile basic nitrogen under irradiation with the predetermined wavelength also varies. The composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots in the embodiment of the present invention is a composite nanomaterial originally prepared by the present invention.

[0058] Figure 3 Schematic diagram of the principle of the meat product freshness detection method provided by the present invention. Figure 3 As shown, in the embodiment of the present invention, when it is necessary to detect the freshness of the meat product to be tested, the hydrogel fluorescent electrode 202 can be placed in the detection area of ​​the meat product to be tested, and the hydrogel fluorescent electrode 202 can be irradiated with light of a preset wavelength. Then, based on the intensity of the light signal reflected by the hydrogel fluorescent electrode 202, the content of volatile basic nitrogen generated by the meat product to be tested can be obtained, and then, based on the content of volatile basic nitrogen generated by the meat product to be tested, the freshness of the meat product to be tested can be obtained.

[0059] It should be noted that in embodiments of the present invention, a spherical area with a predetermined radius, centered at the meat product to be tested, can be determined as the detection area for the meat product to be tested. The predetermined radius can be determined based on prior knowledge and / or actual circumstances. For example, the predetermined radius can range from 3 to 20 cm. The specific value of the predetermined radius is not limited in embodiments of the present invention.

[0060] It should be noted that, when it is necessary to detect the freshness of the meat product to be tested, a temperature and humidity sensor can also be placed in the detection area of ​​the meat product to be tested, so as to use the above-mentioned temperature and humidity sensor to obtain the temperature and humidity in the detection area of ​​the meat product to be tested.

[0061] Optionally, in an embodiment of the present invention, when it is necessary to detect the freshness of the meat product to be tested, the hydrogel fluorescent electrode 202, the temperature and humidity sensor and the meat product to be tested can be placed in a closed environment, and it is ensured that the hydrogel fluorescent electrode 202 and the temperature and humidity sensor are within the detection area of ​​the meat product to be tested, thereby further improving the accuracy of freshness detection of the meat product to be tested.

[0062] Step 102: Irradiate the hydrogel fluorescent electrode 202 with light of a preset wavelength, and obtain the temperature and humidity in the detection area of ​​the meat product to be tested.

[0063] Specifically, after the hydrogel fluorescent electrode 202 is placed within the detection area of ​​the meat product to be tested, the hydrogel fluorescent electrode 202 can be illuminated by light of a preset wavelength emitted by the excitation light source module 203. After the light of the preset wavelength is irradiated onto the hydrogel fluorescent electrode 202, the hydrogel fluorescent electrode 202 will reflect the light of the preset wavelength.

[0064] After the temperature and humidity sensor is placed in the detection area of ​​the meat product to be tested, the temperature and humidity sensor can collect the temperature and humidity in the detection area of ​​the meat product to be tested, and send the collected temperature and humidity in the detection area of ​​the meat product to be tested to the processor 206.

[0065] It should be noted that the preset wavelength in the embodiment of the present invention may be determined based on prior knowledge and / or actual conditions. The specific value of the preset wavelength is not limited in the embodiment of the present invention.

[0066] As an optional embodiment, the preset wavelength range includes 360 nm to 380 nm.

[0067] Preferably, the preset wavelength in the embodiment of the present invention may be 370 nm.

[0068] Step 103 : Obtain the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 .

[0069] Specifically, in an embodiment of the present invention, after irradiating the hydrogel fluorescent electrode 202 in the detection area of ​​the meat product to be tested with light of a preset wavelength, the fluorescence detection module 204 can be used to obtain the intensity of the light signal reflected by the hydrogel fluorescent electrode 202, and the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 can be sent to the processor 206.

[0070] As an optional embodiment, obtaining the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 includes: obtaining the intensity of the light signal of a specific wavelength reflected by the hydrogel fluorescent electrode 202 .

[0071] Specifically, in an embodiment of the present invention, after the hydrogel fluorescent electrode 202 in the detection area of ​​the meat product to be tested is irradiated with light of a preset wavelength, the intensity of the light signal of a specific wavelength in the light signal reflected by the hydrogel fluorescent electrode 202 can be collected through the filter and the fluorescence detection module 204, and the intensity of the light signal of the specific wavelength reflected by the hydrogel fluorescent electrode 202 can be sent for processing.

[0072] It should be noted that the specific wavelength may be determined based on prior knowledge and / or actual conditions. In the embodiment of the present invention, the specific wavelength may be 440 nm.

[0073] Step 104 : obtaining the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 and the temperature and humidity in the detection area of ​​the meat product to be tested.

[0074] As an optional embodiment, the freshness of the meat product to be tested is obtained based on the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 and the temperature and humidity in the detection area of ​​the meat product to be tested, including: obtaining the content of volatile basic nitrogen generated by the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode 202.

[0075] The freshness of the meat product to be tested is obtained based on the content of volatile basic nitrogen generated by the meat product to be tested and the temperature and humidity in the testing area of ​​the meat product to be tested.

[0076] Specifically, after the processor 206 obtains the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 sent by the fluorescence detection module 204, it can obtain the content of volatile basic nitrogen generated by the meat product to be tested through numerical calculation, mathematical statistics or deep learning technology. Then, the processor 206 can obtain the freshness of the meat product to be tested based on the content of volatile basic nitrogen generated by the meat product to be tested and the temperature and humidity in the detection area of ​​the meat product to be tested sent by the temperature and humidity sensor through numerical calculation, mathematical statistics, conditional judgment or deep learning technology.

[0077] For example, in the case that the volatile basic nitrogen content generated by the to-be-tested meat product is not more than 15 mg / 100 g, and the temperature and humidity in the detection area of the to-be-tested meat product is in the preset interval, the freshness of the to-be-tested meat product is determined to be 1 (fresh); in the case that the volatile basic nitrogen content generated by the to-be-tested meat product is not more than 15 mg / 100 g, and the temperature and humidity in the detection area of the to-be-tested meat product is not in the preset interval, the freshness of the to-be-tested meat product is determined to be 2 (fresh); in the case that the volatile basic nitrogen content generated by the to-be-tested meat product is greater than 15 mg / 100 g but not more than 25 mg / 100 g, and the temperature and humidity in the detection area of the to-be-tested meat product is in the preset interval, the freshness of the to-be-tested meat product is determined to be 3 (less fresh); in the case that the volatile basic nitrogen content generated by the to-be-tested meat product is greater than 15 mg / 100 g but not more than 25 mg / 100 g, and the temperature and humidity in the detection area of the to-be-tested meat product is not in the preset interval, the freshness of the to-be-tested meat product is determined to be 4 (less fresh); in the case that the volatile basic nitrogen content generated by the to-be-tested meat product is greater than 25 mg / 100 g, and the temperature and humidity in the detection area of the to-be-tested meat product is in the preset interval, the freshness of the to-be-tested meat product is determined to be 5 (spoiled); in the case that the volatile basic nitrogen content generated by the to-be-tested meat product is greater than 25 mg / 100 g, and the temperature and humidity in the detection area of the to-be-tested meat product is not in the preset interval, the freshness of the to-be-tested meat product is determined to be 6 (spoiled). The smaller the value of the freshness of the meat product is, the fresher the meat product is.

[0078] The embodiment of the present application utilizes the specific response characteristics of the hydrogel fluorescent electrode to volatile basic nitrogen, and after the hydrogel fluorescent electrode is placed in the detection area of the to-be-tested meat product, the hydrogel electrode is irradiated with light of a preset wavelength, the intensity of the light signal reflected by the hydrogel fluorescent electrode is detected, and the environmental temperature and humidity in the detection area of the to-be-tested meat product are combined, so that the freshness of the to-be-tested meat product is in-situ, non-destructive and real-time detected, the detection efficiency and accuracy of the freshness of the meat product are significantly improved, the detection process does not require complex instruments and professional operators, and can be directly applied to various scenes such as meat product transportation, storage and sales, breaking through the time and space limitations of laboratory detection, and significantly improving the accuracy of the detection result of the freshness of the meat product through multi-parameter coupling analysis, so as to provide a lightweight freshness detection solution integrated in intelligent packaging for the whole industry chain of meat products.

[0079] As an optional embodiment, the composite nanomaterial is prepared based on the following steps: acidizing halloysite powder to obtain acidized halloysite powder.

[0080] Specifically, halloysite (NHTs) powder is placed in a 1.0 mol / L hydrochloric acid standard solution for repeated acidification and washing (2-3 times, each acidification time is 2-3 hours) to obtain acidified halloysite powder.

[0081] The acidified halloysite powder is mixed with a solution containing nitrogen-doped graphene quantum dots.

[0082] It should be noted that the nitrogen-doped graphene quantum dots (N-GQDs) in the embodiments of the present invention are synthesized based on a hydrothermal method.

[0083] The specific steps for synthesizing nitrogen-doped graphene quantum dots include dissolving 0.945 g of citric acid monohydrate and 0.45 g of urea in 10 mL of deionized water and stirring to form a precursor solution. The precursor solution is poured into a 100 mL stainless steel autoclave lined with polytetrafluoroethylene and heat-treated at 180°C for 12 hours. The resulting yellow-brown mixture is then dialyzed (molecular weight cutoff 1000 Da) for 36 hours, with the water changed every 12 hours, to obtain a pale yellow solution. Finally, the pale yellow solution is freeze-dried to obtain nitrogen-doped graphene quantum dot powder.

[0084] Acidified halloysite powder is added to an aqueous solution containing nitrogen-doped graphene quantum dots, and the mixture is evenly mixed to obtain a mixed solution of the acidified halloysite powder and the nitrogen-doped graphene quantum dots.

[0085] As an optional embodiment, the mass ratio of the acidified halloysite powder to the solution containing nitrogen-doped graphene quantum dots is 1:8.

[0086] Accordingly, 5 mg of acidified halloysite powder was added to a solution containing nitrogen-doped graphene quantum dots with a concentration of 40 mg / L of nitrogen-doped graphene quantum dots, and the mixture was evenly mixed to obtain a mixed solution of acidified halloysite powder and nitrogen-doped graphene quantum dots.

[0087] The mixed solution of the acidified halloysite powder and the nitrogen-doped graphene quantum dots is subjected to vacuum freeze-drying to obtain a composite nanomaterial.

[0088] Specifically, after obtaining a mixed solution of acidified halloysite powder and nitrogen-doped graphene quantum dots, the mixed solution can be subjected to vacuum freeze-drying treatment using a vacuum freeze dryer to obtain a composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots.

[0089] As an optional embodiment, the hydrogel fluorescent electrode 202 is prepared based on the following steps: mixing the composite nanomaterial with a polyvinyl alcohol colloidal solution.

[0090] As an optional embodiment, the polyvinyl alcohol colloidal solution is prepared based on the following steps: The polyvinyl alcohol particles are added to deionized water to prepare a polyvinyl alcohol solution.

[0091] After the polyvinyl alcohol solution is allowed to stand at room temperature for a first preset time, the polyvinyl alcohol solution is stirred at a preset temperature for a second preset time.

[0092] The polyvinyl alcohol solution was cooled to room temperature to obtain a polyvinyl alcohol colloid solution.

[0093] Specifically, the polyvinyl alcohol colloidal solution in the embodiment of the present invention is obtained by the following steps: adding polyvinyl alcohol (PVA) particles to deionized water to prepare a polyvinyl alcohol solution with a mass fraction of 17.5%.

[0094] After the polyvinyl alcohol solution was allowed to stand at room temperature for 1 hour, it was magnetically stirred at 95° C. for 2 hours. After the magnetic stirring was completed, the polyvinyl alcohol solution was cooled to room temperature (25° C.) to obtain a polyvinyl alcohol colloidal solution.

[0095] After obtaining the polyvinyl alcohol colloidal solution and the composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots, the polyvinyl alcohol colloidal solution and the composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots can be added to the polyvinyl alcohol colloidal solution and mixed to obtain a mixed solution of the above composite nanomaterial and the polyvinyl alcohol colloidal solution.

[0096] The mixed solution of the composite nanomaterial and the polyvinyl alcohol colloidal solution is poured into a mold and subjected to repeated freeze-thaw treatment to obtain the hydrogel fluorescent electrode 202 .

[0097] Specifically, after obtaining the mixed solution of the above-mentioned composite nanomaterial and polyvinyl alcohol colloidal solution, the mixed solution of the above-mentioned composite nanomaterial and polyvinyl alcohol colloidal solution can be introduced into a mold, frozen at -18°C for 12 hours, and then thawed at room temperature for 2 hours. The freeze-thaw treatment is repeated three times to obtain the hydrogel fluorescent electrode 202.

[0098] In order to illustrate the performance of the hydrogel fluorescent electrode 202 in the embodiment of the present invention, the performance of the hydrogel fluorescent electrode 202 in the embodiment of the present invention is verified through several practical applications below.

[0099] Experiment 1 is an experiment to verify the response of the above-mentioned composite nanomaterials to ammonia.

[0100] A composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots was added to a phosphate buffered saline (PBS) solution to produce a test solution containing the composite nanomaterial at a concentration of 0.045 mg / ml. The pH of the test solution was 7. After the test solution was allowed to stand at room temperature for 10 minutes, the initial fluorescence emission spectrum of the test solution was recorded. The test solution was then excited with light at a wavelength of 370 nm, and the fluorescence emission spectrum of the test solution under excitation at 370 nm was recorded.

[0101] Based on the initial fluorescence emission spectrum of the test mixed solution and the fluorescence emission spectrum of the test mixed solution under the excitation of 370 nm light, a calibration curve of the fluorescence intensity and ammonia concentration of the test mixed solution at an emission wavelength of 440 nm was drawn.

[0102] Figure 4 It is a fluorescence spectrum diagram of the test mixed solution in the meat product freshness detection method provided by the present invention in an environment of ammonia with different concentrations. Figure 5 This is a fluorescence intensity calibration diagram of a test mixed solution in the meat product freshness detection method provided by the present invention.

[0103] like Figure 4 As shown, with the increase of ammonia concentration, the fluorescence intensity of the test mixed solution containing the composite nanomaterials at the emission wavelength of 440 nm decreased significantly.

[0104] Figure 5 F0 represents the initial fluorescence intensity of the test mixed solution, and F represents the fluorescence intensity of the test mixed solution after adding ammonia. The ratio of F0 to F (F0 / F) has a good linear relationship with the concentration of ammonia (R 2 =0.96).

[0105] The limit of detection (LOD) of the fluorescent probe in the test mixed solution was 3.62 ppm, calculated using the formula 3σ / s (where σ is the standard deviation of the blank probe sample measurement and s is the slope of the linear calibration curve).

[0106] Experiment 2 is an experiment to verify the selectivity, stability and repeatability of the above-mentioned composite nanomaterials.

[0107] In order to verify the selectivity, stability and repeatability of the above-mentioned composite nanomaterials, some potential influencing substances, such as CO2, NO, NO2, H2S, ethanol, acetic acid, MMA, DMA and TMA, were studied in the embodiments of the present invention to determine their effects on the fluorescence intensity of the hydrogel fluorescent electrode 202.

[0108] The hydrogel fluorescent electrode 202 was placed in different environments (CO2, NO, NO2, H2S, NH3, ethanol, acetic acid, monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA)) to obtain the fluorescence intensity of the hydrogel fluorescent electrode 202 in different environments.

[0109] Figure 6 Schematic diagram of the selectivity of the hydrogel fluorescent electrode in the meat product freshness detection method provided by the present invention. Figure 6 As shown, hydrogel fluorescent electrode 202 showed the strongest response to NH₃, and also showed good responses to DMA and TMA. The fluorescence change of hydrogel fluorescent electrode 202 in the DMA environment was 15%, in the TMA environment was 13%, and in the NH₃ environment was 35%. Since these three substances are factors affecting the freshness of meat products, the effects of other substances on the fluorescence change rate of hydrogel fluorescent electrode 202 can be ignored.

[0110] The experimental results show that the selectivity of the hydrogel fluorescent electrode 202 for NH 3 is higher than that for other substances. Therefore, the hydrogel fluorescent electrode 202 has higher sensitivity and stronger selectivity for detecting NH 3.

[0111] The fluorescence intensity of the hydrogel fluorescent electrode 202 was continuously monitored at room temperature. Starting from day 0, the fluorescence intensity of the hydrogel fluorescent electrode 202 was measured every two days until day 12. The measured data was recorded and processed. The stability of the hydrogel fluorescent electrode 202 was studied by observing the changes in the fluorescence intensity of the hydrogel fluorescent electrode 202.

[0112] Figure 7 Schematic diagram of the stability of the hydrogel fluorescent electrode in the meat product freshness detection method provided by the present invention. Figure 7 The results show that the fluorescence intensity of the hydrogel fluorescent electrode 202 did not change significantly within 12 days, and had good stability.

[0113] The repeatability of the hydrogel fluorescent electrode 202 can be verified by repeatedly placing the hydrogel fluorescent electrode 202 in an ammonia environment and an environment without ammonia and detecting the change in fluorescence intensity of the hydrogel fluorescent electrode 202 before and after being placed in the ammonia environment.

[0114] Figure 8 Schematic diagram of the repeatability of the hydrogel fluorescent electrode in the meat product freshness detection method provided by the present invention. Figure 8As shown, the fluorescence intensity of the hydrogel fluorescent electrode 202 in the fifth repeated test is 88.1% of the fluorescence intensity of the hydrogel fluorescent electrode 202 in the first repeated test, thus proving that the hydrogel fluorescent electrode 202 has good repeatability and can be reused.

[0115] Based on the contents of the above embodiments, the meat product freshness detection device 201 includes: an excitation light source module 203, a hydrogel fluorescent electrode 202, a fluorescence detection module 204, a temperature and humidity detection module 205 and a processor 206; the hydrogel fluorescent electrode 202 includes a composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots. When the hydrogel fluorescent electrode 202 is irradiated with light of a preset wavelength, the absorption intensity of the preset wavelength of light in different concentrations of volatile basic nitrogen is different.

[0116] The excitation light source module 203 is used to emit light of a preset wavelength to illuminate the hydrogel fluorescent electrode 202 .

[0117] The fluorescence detection module 204 is used to collect the light signal reflected by the hydrogel fluorescent electrode 202 , and convert the collected light signal into a voltage value and send it to the processor 206 .

[0118] The temperature and humidity detection module 205 is used to collect the temperature and humidity in the detection area of ​​the meat product to be tested, and send the collected temperature and humidity in the detection area of ​​the meat product to be tested to the processor 206.

[0119] The processor 206 is used to obtain the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 based on the received voltage value, and then obtain the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 and the temperature and humidity in the detection area of ​​the meat product to be tested.

[0120] Specifically, when the freshness of the meat product to be tested needs to be detected, the hydrogel fluorescent electrode 202 and the temperature and humidity sensor are placed in the detection area of ​​the meat product to be tested, and the hydrogel fluorescent electrode 202 is irradiated with light of a preset wavelength emitted by the excitation light source module 203.

[0121] After the light of the preset wavelength is irradiated onto the hydrogel fluorescent electrode 202 , the hydrogel fluorescent electrode 202 reflects the light of the preset wavelength.

[0122] The fluorescence detection module 204 can collect the light signal reflected by the hydrogel fluorescent electrode 202 and convert the collected light signal into an electrical signal through the photovoltaic effect. After amplification by the operational amplifier circuit, the analog-to-digital converter (ADC) collects the voltage value of the above electrical signal, and then sends the above voltage value to the processor 206, so that the processor 206 can calculate the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 based on the received voltage value.

[0123] The excitation light source module 203 in the embodiment of the present invention includes a purple high-power light emitting diode, which can emit light with a wavelength of 370 nm.

[0124] Figure 9 This is a physical picture of the purple high-power light emitting diode in the meat product freshness detection device provided by the present invention. Figure 9 shown.

[0125] Optionally, the excitation light source module 203 in the embodiment of the present invention may further include a timing cycle submodule, which includes a timing cycle unit, a 5V constant voltage unit, a 5V to 3.3V constant voltage constant current module and a 5V lithium battery. Figure 10 The physical picture of the timing cycle submodule in the meat product freshness detection device provided by the present invention. The physical picture of the timing cycle submodule in the excitation light source module 203 is as follows: Figure 10 shown.

[0126] The wavelength range of the purple high-power LED can match the peak wavelength of nitrogen-doped graphene quantum dots. The normal operating voltage of the purple high-power LED is 3.2-3.6V and the operating current is 700mA.

[0127] The driving circuit of the excitation light source module 203 is controlled by a constant voltage and constant current driving module, which can achieve a continuously adjustable output voltage of 1.25-36V and a maximum output current of 5A.

[0128] The timing cycle submodule in the excitation light source module 203 can set the light off time, light on time and the number of cycles by adjusting the buttons on the timing cycle unit. The timing cycle submodule can be controlled by the processor 206.

[0129] Figure 11 The schematic diagram of the principle of the timing cycle submodule in the meat product freshness detection device provided by the present invention is as follows. Figure 11 shown.

[0130] Optionally, the processor 206 in the embodiment of the present invention may be a single-chip processor 206 .

[0131] Preferably, the processor 206 in the embodiment of the present invention can be a STC89C52RC type processor 206. This type of processor 206 not only has powerful data processing and computing capabilities, but also has low power consumption and cost advantages, and can meet the requirements of the meat product freshness detection device 201 provided by the present invention.

[0132] The processor 206 in the embodiment of the present invention mainly includes a main control chip, a download socket, a temperature and humidity sensor (DHT22), a BH1750 light intensity sensor, a 0.96-inch OLED LCD screen, a power circuit, a 485 circuit, a key control, a buzzer alarm and a wireless communication module.

[0133] Figure 12 The physical image of the processor in the meat product freshness detection device provided by the present invention. The physical image of the processor 206 in the meat product freshness detection device 201 is as follows: Figure 12 shown.

[0134] Figure 13 The schematic diagram of the principle of the processor in the meat product freshness detection device provided by the present invention is as follows. Figure 13 shown.

[0135] Fluorescence detection module 204 is a key component of meat product freshness detection device 201. Its performance plays a crucial role in the accuracy, sensitivity, and stability of meat product freshness detection device 201. Fluorescence detection module 204 converts light signals into electrical signals, and its basic principle relies on the photoelectric effect.

[0136] Optionally, in this embodiment of the present invention, a digital light intensity sensor model BH1750 is selected as the primary fluorescence detection module 204. The digital light intensity sensor comprises a photodiode, an operational amplifier, an ADC acquisition module, and a crystal oscillator. The photodiode utilizes the photovoltaic effect to convert the input light signal into an electrical signal, which is then collected by the ADC acquisition module. Subsequently, after processing by a logic circuit, the voltage signal is converted into a 16-bit binary number and stored in an internal register. The intensity of the input light signal is proportional to the photocurrent; the higher the intensity of the input light signal, the higher the current and corresponding voltage.

[0137] Figure 14 The schematic diagram of the principle of the fluorescence detection module in the meat product freshness detection device provided by the present invention is as follows. Figure 14 shown.

[0138] Optionally, the DHT22 digital temperature and humidity sensor is selected as the temperature and humidity detection module 205 in the embodiment of the present application. The DHT22 digital temperature and humidity sensor described above includes a calibrated temperature and humidity sensor, which can output a digital signal. The DHT22 digital temperature and humidity sensor mainly consists of a resistance type humidity sensing element and a negative temperature coefficient (NTC) temperature sensor. This design makes the DHT22 digital temperature and humidity sensor have a wider measurement range and higher measurement accuracy, which can provide reliable data support for temperature and humidity monitoring in the detection area of the meat product to be detected.

[0139] Figure 15 is a principle diagram of the temperature and humidity detection module in the meat product freshness detection device provided by the present application. The operation principle of the temperature and humidity detection module 205 in the meat product freshness detection device 201 is as shown in Figure 15

[0140] As an optional embodiment, the meat product freshness detection device 201 further comprises a filter.

[0141] The filter is arranged between the hydrogel fluorescent electrode 202 and the hydrogel fluorescent electrode 202, and is used for filtering the light signal reflected by the hydrogel fluorescent electrode 202.

[0142] Specifically, the hydrogel fluorescent electrode 202 and the temperature and humidity sensor are placed in the detection area of the meat product to be detected, and after the preset wavelength light emitted by the excitation light source module 203 irradiates the hydrogel fluorescent electrode 202, the fluorescence detection module 204 can collect the light signal reflected by the hydrogel fluorescent electrode 202 through the filter.

[0143] It should be noted that the filter described above can filter out waves of other wavelengths except for a specific wavelength. The specific wavelength can be determined based on prior knowledge and / or actual situation. The specific wavelength can be 440nm.

[0144] Figure 16 is a second structural diagram of the meat product freshness detection device provided by the present application. As shown in Figure 16 The meat product freshness detection device in the embodiment of the present application can further include an alarm, a display device and a communication module.

[0145] Figure 17 is a program flow chart of the meat product freshness detection device provided by the present application. As shown in Figure 17 ​As shown, after the meat product freshness detection device 201 is turned on, it will first initialize the display interface of the peripherals and display device, and check whether the current display mode is normal. If the current display mode is normal, the meat product freshness detection device 201 will start to detect the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 and the temperature and humidity in the detection area of ​​the meat product to be tested, and transmit the collected data to the processor 206 and the cloud platform in real time. The processor 206 can obtain the freshness of the meat product to be tested based on the received data, and determine whether the freshness of the meat product to be tested is lower than the preset freshness threshold. If it is determined that the freshness of the meat product to be tested is lower than the preset freshness threshold, the buzzer is controlled to alarm. If the display mode is abnormal, press any key and the meat product freshness detection device 201 will enter the setting function interface.

[0146] In order to verify the feasibility of the meat product freshness detection device 201 provided by the present invention, the meat product freshness detection device 201 provided by the present invention was used to detect the freshness of the meat product under refrigeration conditions (4°C) and room temperature conditions (25°C).

[0147] A meat product freshness detection device 201 is stored together with a meat product to be tested in an acrylic box, and a meat product freshness detection device 201 is stored together with another meat product to be tested in another acrylic box. The above two acrylic boxes are stored in a refrigerator (4°C) and room temperature (25°C) respectively.

[0148] Under 4°C storage conditions, the fluorescence detection module 204 in the meat product freshness detection device 201 detects the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 once a day. Under 25°C storage conditions, the sensor detects the intensity of the light signal reflected by the hydrogel fluorescent electrode 202 every 6 hours.

[0149] Figure 18 It is a fitting curve of the intensity of the light signal reflected by the hydrogel fluorescent electrode detected by the fluorescence detection module of the meat product freshness detection device provided by the present invention under different storage conditions and the content of volatile basic nitrogen generated by the meat product to be tested.

[0150] like Figure 18 As shown, with the passage of time, the colors of the meat products to be tested in the two acrylic boxes gradually changed from bright red to dark red, and the intensities of the light signals reflected by the hydrogel fluorescent electrodes 202 in the freshness detection devices 201 for the meat products to be tested in the two acrylic boxes gradually decreased. This is because the quality of the meat products to be tested in the two acrylic boxes deteriorated and produced a large amount of ammonia-containing substances, which caused the fluorescence intensity of the hydrogel fluorescent electrodes 202 to change through static quenching.

[0151] In order to further illustrate the practicality of the meat product freshness detection device 201 provided by the present invention, the meat product freshness detection device 201 provided by the present invention is described below through two examples.

[0152] Example 1 is an application of the meat product freshness detection device 201 provided by the present invention to monitor the freshness changes of meat products in real time during the cold chain transportation of meat products.

[0153] In Example 1, the meat product to be tested is obtained after being weighed, the meat product to be tested and the meat product freshness detection device 201 are placed in a closed space, and the meat product freshness detection device 201 is started.

[0154] Meat product freshness detection device 201 starts working, displaying the freshness of the meat product in real time on the display device. It also displays the freshness of the meat product in real time on the mobile phone app and the host computer, and stores the data so that transport personnel can view the data in real time. Transport personnel can adjust storage and transportation strategies based on the test results of meat product freshness detection device 201.

[0155] Example 1 demonstrates that the meat product freshness detection device 201 provided by the present invention can accurately, in real time, and non-destructively detect the freshness of a meat product. Furthermore, the meat product freshness detection device 201 provided by the present invention can reduce the cost of real-time testing of meat products during storage and transportation, making meat product freshness detection more efficient and convenient.

[0156] Example 2 is an application of the meat product freshness detection device 201 provided by the present invention to monitor the freshness changes of household stored meat products in real time.

[0157] In Example 2, a meat product purchased by a household is identified as the meat product to be tested. The meat product to be tested is stored in a refrigerator together with the meat product freshness detection device 201, and the meat product freshness detection device 201 is activated. The meat product freshness detection device 201 begins operation, displays the freshness of the meat product to be tested on the household user's mobile phone app in real time, and stores the freshness of the meat product to be tested. If the freshness of the meat product to be tested falls below a preset freshness threshold, the meat product freshness detection device 201 will alarm the household user to remind him that the meat product is not recommended for consumption.

[0158] Example 2 illustrates that the meat product freshness detection device 201 provided by the present invention can display the freshness of the purchased meat products to home users in real time, so that home users can see the freshness of the purchased meat products at a glance, which helps to reduce the waste of meat products and ensure the healthy diet of home users.

[0159] The meat product freshness detection device in an embodiment of the present invention includes an excitation light source module, a hydrogel fluorescent electrode, a fluorescence detection module, a temperature and humidity detection module, and a processor. Utilizing the specific response characteristics of the hydrogel fluorescent electrode to volatile basic nitrogen, the hydrogel fluorescent electrode is placed within a detection area of ​​the meat product to be tested. The hydrogel fluorescent electrode is then illuminated with light of a preset wavelength emitted by the excitation light source module. The intensity of the light signal reflected by the hydrogel fluorescent electrode is detected by the fluorescence detection module. Combined with the ambient temperature and humidity within the detection area of ​​the meat product to be tested, as collected by the temperature and humidity detection module, the device can more accurately and efficiently obtain the freshness of the meat product to be tested. This enables in-situ, non-destructive, and real-time detection of the freshness of the meat product to be tested, significantly improving the efficiency and accuracy of meat product freshness detection. The detection process does not require complex instruments and professional operators and can be directly applied to various scenarios such as meat product transportation, warehousing, and sales. This breaks through the temporal and spatial limitations of laboratory testing. Through multi-parameter coupling analysis, the accuracy of meat product freshness detection results is significantly improved. This solution can provide a lightweight freshness detection solution that can be integrated into smart packaging for the entire meat product industry chain.

[0160] The meat product freshness detection device 201 provided by the present invention studies and synthesizes a hydrogel fluorescent electrode 202 that specifically responds to volatile basic nitrogen generated during the spoilage process of meat products, prepares a portable meat product freshness detection device 201, combines the hydrogel fluorescent electrode 202 with a sensing device, and performs functional testing and practical application of the sensor. This provides users with a portable meat product freshness detection device 201 that can realize real-time and non-destructive detection of the freshness of meat products.

[0161] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for detecting the freshness of meat products, characterized in that: include: placing the hydrogel fluorescent electrode in the detection area of ​​the meat product to be tested; irradiating the hydrogel fluorescent electrode with light of a preset wavelength and obtaining the temperature and humidity within the detection area of ​​the meat product to be tested; Obtaining the intensity of the light signal reflected by the hydrogel fluorescent electrode; Obtaining the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of ​​the meat product to be tested; The hydrogel fluorescent electrode comprises a composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots. When irradiated with light of the preset wavelength, the hydrogel fluorescent electrode has different absorption intensities for light of the preset wavelength in different concentrations of volatile basic nitrogen.

2. The meat product freshness detection method according to claim 1, characterized in that: The composite nanomaterial is prepared based on the following steps: acidifying the halloysite powder to obtain acidified halloysite powder; mixing the acidified halloysite powder with a solution containing nitrogen-doped graphene quantum dots; The mixed solution of the acidified halloysite powder and the nitrogen-doped graphene quantum dots is subjected to vacuum freeze-drying treatment to obtain the composite nanomaterial.

3. The meat product freshness detection method according to claim 2, characterized in that: The mass ratio of the acidified halloysite powder to the solution containing nitrogen-doped graphene quantum dots is 1:

8.

4. The method for detecting the freshness of meat products according to claim 2, wherein: The hydrogel fluorescent electrode is prepared based on the following steps: mixing the composite nanomaterial with a polyvinyl alcohol colloidal solution; A mixed solution of the composite nanomaterial and the polyvinyl alcohol colloid solution is poured into a mold and subjected to repeated freeze-thaw treatment to obtain the hydrogel fluorescent electrode.

5. The method for detecting the freshness of meat products according to claim 4, characterized in that: The polyvinyl alcohol colloid solution is prepared based on the following steps: Adding polyvinyl alcohol particles to deionized water to prepare a polyvinyl alcohol solution; After the polyvinyl alcohol solution is allowed to stand at room temperature for a first preset time, the polyvinyl alcohol solution is stirred at a preset temperature for a second preset time; The polyvinyl alcohol solution is cooled to room temperature to obtain the polyvinyl alcohol colloid solution.

6. The method for detecting the freshness of meat products according to claim 1, wherein: The preset wavelength ranges from 360 nm to 380 nm.

7. The method for detecting the freshness of meat products according to claim 6, characterized in that: The obtaining the intensity of the light signal reflected by the hydrogel fluorescent electrode comprises: The intensity of the light signal of a specific wavelength reflected by the hydrogel fluorescent electrode is obtained.

8. The method for detecting the freshness of meat products according to any one of claims 1 to 7, characterized in that: The method of obtaining the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of ​​the meat product to be tested includes: Obtaining the volatile basic nitrogen concentration of the environment where the hydrogel fluorescent electrode is located based on the intensity of the light signal reflected by the hydrogel fluorescent electrode; The freshness of the meat product to be tested is obtained based on the volatile basic nitrogen concentration of the environment where the hydrogel fluorescent electrode is located and the temperature and humidity in the detection area of ​​the meat product to be tested.

9. A meat product freshness detection device for implementing the meat product freshness detection method according to any one of claims 1 to 8, characterized in that: include: An excitation light source module, a hydrogel fluorescent electrode, a fluorescence detection module, a temperature and humidity detection module, and a processor; the hydrogel fluorescent electrode comprises a composite nanomaterial of halloysite and nitrogen-doped graphene quantum dots, and the hydrogel fluorescent electrode, under irradiation with light of a preset wavelength, has different absorption intensities for light of the preset wavelength in different concentrations of volatile basic nitrogen; The excitation light source module is used to emit light of the preset wavelength to illuminate the hydrogel fluorescent electrode; The fluorescence detection module is used to collect the light signal reflected by the hydrogel fluorescent electrode, and convert the collected light signal into a voltage value and then send it to the processor; The temperature and humidity detection module is used to collect the temperature and humidity in the detection area of ​​the meat product to be tested, and send the collected temperature and humidity in the detection area of ​​the meat product to be tested to the processor; The processor is used to obtain the intensity of the light signal reflected by the hydrogel fluorescent electrode based on the received voltage value, and then obtain the freshness of the meat product to be tested based on the intensity of the light signal reflected by the hydrogel fluorescent electrode and the temperature and humidity in the detection area of ​​the meat product to be tested.

10. The meat product freshness detection device according to claim 9, characterized in that: Also includes: optical filters; The filter is arranged between the hydrogel fluorescent electrodes and is used for filtering the light signal reflected by the hydrogel fluorescent electrodes.

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