A color-changing and visual food corruption detection device and detection method thereof

Abstract

The present invention discloses a color-changing and visual food corruption detection device, comprising a shell, an ultraviolet light source, an ultraviolet filter, a filter rack, a detection material rack and a power module; the ultraviolet light source, the filter rack, the detection material rack and the power module are all arranged in the shell; the ultraviolet filter is placed on the filter rack; a detection window is provided on the shell, and the detection window, the detection material rack, the filter rack and the ultraviolet light source are arranged in sequence, and the light of the ultraviolet light source irradiates the ultraviolet filter and the detection material rack in sequence; the ultraviolet light source is connected to the power module; the device has the advantages of high integration, small size, simple structure, low cost, strong practicality and stable low-temperature performance, and the detection method using the color-changing and visual food corruption detection device has high sensitivity and the detection results are intuitively visible.

Description

Technical Field

[0001] The present invention relates to the technical field of food detection, and more particularly to a color-changing and visualized food corruption detection device and a detection method thereof. Background Art

[0002] With the continuous improvement of living standards, people have higher requirements for the quality of life, and their choices have shifted from singleness to diversification. The consumption of perishable foods such as fresh vegetables, fruits, and dairy products has continued to increase. After food is spoiled, the structure of protein, fat, and carbohydrates contained in it changes, and the original nutritional value is reduced or even lost. In addition, the color, aroma, and taste of the food deteriorate. What is more serious is that due to serious microbial contamination, the chances of pathogenic bacteria and toxin-producing bacteria in spoiled food increase significantly, which can cause food poisoning or other potential hazards after consumption.

[0003] Traditional methods for evaluating food spoilage include sensory evaluation, physical and chemical index testing, and colony count testing. Although sensory evaluation is simple and easy, the evaluation process is easily influenced by subjectivity, has poor repeatability, and poses a greater health risk. Although the other two methods produce objective and accurate diagnostic results, they are relatively time-consuming, require complex equipment, are costly, and difficult to operate. They are particularly unsuitable for applications such as food spoilage detection that require high real-time performance. Summary of the Invention

[0004] The main purpose of the present invention is to overcome the above-mentioned shortcomings and provide a food corruption detection device and a detection method with color-changing visualization based on a fluorescent substance that responds to corrupted gas, which are used to judge the freshness and storage condition of food. It has great application value in applications where high real-time requirements are required for food corruption detection.

[0005] The present invention provides a color-changing and visualized food corruption detection device, comprising a housing, an ultraviolet light source, an ultraviolet filter, a filter rack, a detection material rack and a power module; the ultraviolet light source, the filter rack, the detection material rack and the power module are all arranged in the housing; the ultraviolet filter is placed on the filter rack; a detection window is provided on the housing, and the detection window, the detection material rack, the filter rack and the ultraviolet light source are arranged in sequence, and the light of the ultraviolet light source irradiates the ultraviolet filter and the detection material rack in sequence; the ultraviolet light source is connected to the power module.

[0006] Furthermore, the shell fixes the switch through the switch fixing hole, and the switch is connected to the power module.

[0007] Furthermore, a battery fixing slot is provided in the shell to fix the battery, and the battery is connected to the power module.

[0008] Furthermore, it also includes a light source bracket and a power module bracket, the ultraviolet light source is arranged on the light source bracket, and the power module is arranged on the power module bracket.

[0009] Furthermore, an adhesive fixing groove is provided on the shell.

[0010] Furthermore, a soft magnetic material frame is provided between the shell cover and the side plate of the shell, and soft magnetic material is placed on the soft magnetic material frame.

[0011] The present invention also provides a detection method of the color-changing and visual food corruption detection device, comprising the following steps:

[0012] S1. Preparing the detection material: heating and solidifying the fluorescent substance and the carrier into a gel, and cutting the gel into sheets to obtain the detection material;

[0013] S2. Take the test materials as blank samples and test samples respectively. Seal the test samples and food, and seal the blank samples. Before testing, take out the test samples and blank samples and place them at both ends of the test material rack respectively.

[0014] S3. Place the color-changing and visualized food corruption detection device in a dark environment, turn on the switch, and simultaneously illuminate the blank sample and the test sample with the ultraviolet light source. Collect images and extract the green fluorescence intensity, which is converted into a green fluorescence intensity-time curve.

[0015] Furthermore, in step S1, the fluorescent substance includes nano ZnCeS or zinc oxide quantum dots.

[0016] Furthermore, in step S1, the temperature of heating and curing is 65-75° C., and the time is 20-40 min.

[0017] The technical concept of the present invention is to use a fluorescent substance that responds to corrupted gases, because the fluorescent substance can be excited to fluoresce by ultraviolet rays of a specific wavelength; if the environment contains corrupted gases, the fluorescent substance is quenched and does not emit fluorescence; in many cases, an obvious sign of food spoilage is the production of corrupted gases, such as sulfides, amine compounds, etc.; ultraviolet rays emitted by the ultraviolet light source are emitted into the detection material (sheet gel containing fluorescent substance) on the detection material rack through an ultraviolet filter, so that people can observe the fluorescence changes; the detection of green fluorescence intensity can be qualitatively evaluated by the naked eye, or it can be photographed and then the green fluorescence intensity can be extracted using Photoshop, and a curve of green fluorescence intensity change over time can be drawn to achieve quantitative analysis of the green fluorescence intensity. Therefore, ultraviolet fluorescence detection of the fluorescent substance can very sensitively detect the presence or absence of corrupted gases, thereby indirectly detecting the spoilage condition of the food.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The color-changing and visual food corruption detection device of the present invention has the advantages of high integration, small size, simple structure, low cost, strong practicality, and stable low-temperature performance. The detection method using the color-changing and visual food corruption detection device has high sensitivity and the detection results are intuitively visible. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the detection principle of the color change visualization food spoilage detection method of the present invention;

[0021] Figure 2 This is a schematic diagram of the three-dimensional structure of the color-changing, visual food spoilage detection device of the present invention; wherein 1 is the housing, 2 is the ultraviolet light source, 3 is the filter holder, 4 is the detection material holder, 5 is the power module, 6 is the light source bracket, 7 is the power module bracket, 11 is the detection window, 12 is the switch fixing hole, 13 is the battery fixing slot, 14 is the adhesive fixing slot, 15 is the housing cover, 16 is the side panel, and 17 is the soft magnetic material holder;

[0022] Figure 3 This is the test result of the blank sample in Example 1;

[0023] Figure 4 The test results of the test sample in Example 1 are as follows;

[0024] Figure 5 The green fluorescence intensity-time curve of the detection result in Example 1;

[0025] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby more clearly defining the protection scope of the present invention.

[0027] Example 1

[0028] This embodiment provides a color-changing and visual food corruption detection device. Figure 2As shown, it includes a shell 1, an ultraviolet light source 2, an ultraviolet filter, a filter holder 3, a detection material holder 4, a power module 5, a light source bracket 6 and a power module bracket 7; the shell 1 is made of opaque high-performance nylon; the ultraviolet light source 2, the filter holder 3, the detection material holder 4 and the power module 5 are all arranged in the shell 1; the ultraviolet filter is placed on the filter holder 3; a detection window 11 is provided on the shell 1, and the detection window 11, the detection material holder 4, the filter holder 3 and the ultraviolet light source 2 are arranged in sequence, the ultraviolet light source 2 is arranged on the light source bracket 6, and the power module 5 is arranged on the power module bracket 7.

[0029] When in use, the light from the ultraviolet light source 2 sequentially illuminates the ultraviolet filter of the filter holder 3 and the detection material of the detection material holder 4. Since the fluorescent substance in the detection material can be excited to fluoresce by ultraviolet rays of a specific wavelength, the fluorescence change can be observed with the naked eye.

[0030] Among them, the ultraviolet filter has a transmittance of no less than 80% for ultraviolet rays with a wavelength of around 310 nm; the ultraviolet light source 2 is connected to the power module 5, and the light-emitting element of the ultraviolet light source 2 is a packaged chip LED, which is arranged on an aluminum substrate and connected in parallel, and its bottom is fixed on an aluminum heat sink.

[0031] The housing 1 is provided with a switch fixing hole 12 for fixing the switch, which is connected to the power module 5 .

[0032] The battery is fixed in the bottom of the shell 1 by opening a battery fixing groove 13, and the battery is connected to the power module 5. The battery of this embodiment adopts a lithium battery with good stability, and a manganese-zinc battery or the like can also be adopted; the power module 5 is provided with a control and voltage regulation circuit with a boost function, which can increase the output voltage of the lithium battery to 5.5 V; it has a battery charging function, and the charging interface is a micro-USB interface; it has an overcharge protection function; and it has a manual output voltage adjustment function.

[0033] Specifically, the housing 1 is provided with an adhesive fixing groove 14 for fixing it at a desired location, such as a wall.

[0034] A soft magnetic material frame 17 is provided between the shell cover 15 and the two side plates 16 of the shell 1, which is used to clamp and fix the shell cover 15. The soft magnetic material is placed on the soft magnetic material frame 17. Specifically, the soft magnetic material is 1.5 mm thick and has the same size as the soft magnetic material frame 17. It has adhesive backing and is used to fix the shell cover 15 and the side plates 16 and is easy to separate.

[0035] This embodiment also provides a detection method of the above-mentioned color change and visualization food corruption detection device, comprising the following steps:

[0036] S1. Preparation of test materials:

[0037] The fluorescent material used is zinc oxide quantum dots. The preparation of zinc oxide quantum dots (ZnO QDs) that emit yellow light and have an average diameter of 4.3 nm is as follows:

[0038] Zn(Ac)2·2H2O (0.8716 g) was dissolved in boiling anhydrous ethanol (20 ml), and deionized water (50 μl) was added dropwise. The emission wavelength of the ZnO quantum dots can be adjusted by adjusting the amount of deionized water added. The mixture was then refluxed to 90°C with vigorous stirring, and the reaction mixture was cooled to 0°C. LiOH·H2O (0.2367 g) powder was added to the solution under ultrasound. The solution was sonicated continuously for 3 hours until the ZnO colloidal solution became transparent. Finally, n-hexane (ethanol:n-hexane volume ratio of 1:3) was added to the clear ZnO ethanol solution. The solution was centrifuged at 1500 rpm, the supernatant removed, and the ZnO precipitate was redispersed by adding the same volume of anhydrous ethanol.

[0039] Preparation of ZnO QD-PDMS composite:

[0040] The purified zinc oxide nanoparticle colloid was diluted 5 times with anhydrous ethanol, and 2 ml was taken and mixed with PDMS prepolymer component A (20.0 g, the volume ratio of ZnO ethanol solution to PDMS prepolymer component A = 1:10), and ultrasonically treated at room temperature for 4 hours; PDMS prepolymer group B (2.0 g) was added, in a cross-linked state, and thoroughly mixed with the PDMS A / ZnO mixture; moved into a drying oven, controlled the temperature at 70 ° C, heated and cured for 40 minutes, then taken out of the drying oven, opened the lid, and cut the dried gel-like detection material into 2×20 mm×15 mm pieces and took them out to obtain a detection material containing fluorescent nano-zinc oxide quantum dots.

[0041] S2. Cut two pieces of test material slightly smaller than 2 x 20 x 15 mm; one piece is exposed to the corrosive gas, and the other is not exposed to the corrosive gas. The test material not exposed to the corrosive gas is the blank sample, and the test material exposed to the corrosive gas is the test sample; the blank sample is placed in a sealed bag and sealed; the test sample is attached to the surface of the food and placed in a sealed bag together with the food, and sealed; the blank sample and the test sample are stored under the same conditions; the blank sample and the test sample are tested using a food corruption detection device; during the test, first open the shell cover of the food corruption detection device, remove the test sample and blank sample respectively, insert the blank sample into the left side of the test material rack, and insert the test sample into the right side of the test material rack, and install the shell cover back into the device;

[0042] S3. Place the food corruption detection device in a completely dark environment and turn on the switch. At this time, the ultraviolet light source can illuminate the blank sample and the test sample at the same time. Use a camera to take pictures. Figure 3 、 4As shown in the figure, the green fluorescence intensity of the test sample weakens due to the reaction of the corrosive gas with the fluorescent substance, and appears darker than the blank sample. The green fluorescence intensity values ​​of the blank sample and the test sample in each photo are extracted. The green fluorescence intensity values ​​of the blank sample and the test sample in each photo are processed 5 times, and the green fluorescence intensity of 5 points is taken each time. Then the standard deviation is taken. The green fluorescence intensity is converted into a curve, where the horizontal axis is time and the vertical axis is green fluorescence intensity. From the green fluorescence intensity-time curve of the blank sample and the test sample, as shown in the figure, Figure 5 As shown in FIG, the corrosive gas in the test sample reacts with the fluorescent substance, causing the green fluorescence intensity to weaken. Therefore, the green fluorescence intensity-time curve of the test sample shows a downward trend, while the green fluorescence intensity-time curve of the blank sample shows a flat trend, as shown in FIG. Figure 1 This is a schematic diagram of the detection principle of the color-changing visualized food spoilage detection method of this embodiment. Because the corrupted gas reacts with the zinc oxide quantum dots, the fluorescence of the zinc oxide quantum dots is quenched under ultraviolet irradiation.

[0043] Therefore, the food corruption detection device of the present invention can reflect the influence of the corruption gas generated by the food on the detection material, thereby judging the freshness and storage condition of the food.

[0044] Example 2

[0045] This embodiment is similar to embodiment 1, except that the fluorescent substance used in the preparation of the detection material is nano-ZnCeS. The detection material of this embodiment is prepared as follows:

[0046] S1. Take 0.02 g of fluorescent nano-ZnCeS and 20 g of plastic precursor solution (PDMS) and add them to a clean container; stir the contents of the container evenly, pour them into a mold with a diameter of 20 mm to form a liquid surface with a thickness of 2 mm, and cover the mold with a lid; move the mold into a drying oven, control the temperature to 75°C, heat and cure for 30 minutes, and then take it out; take the mold out of the drying oven, open the lid, cut the test material that has been dried into a gel into 2×20 mm×15 mm pieces and take them out to obtain a test material containing fluorescent nano-ZnCeS.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for detecting food spoilage by color change visualization, characterized in that: A food spoilage detection device with color change visualization is used, and the detection device comprises a housing (1), an ultraviolet light source (2), an ultraviolet filter, a filter rack (3), a detection material rack (4) and a power module (5); the ultraviolet light source (2), the filter rack (3), the detection material rack (4) and the power module (5) are all arranged in the housing (1); the ultraviolet filter is placed on the filter rack (3); a detection window (11) is provided on the housing (1), the detection window (11), the detection material rack (4), the filter rack (3) and the ultraviolet light source (2) are arranged in sequence, and the light of the ultraviolet light source (2) irradiates the ultraviolet filter and the detection material rack (4) in sequence; the ultraviolet light source (2) is connected to the power module (5); The detection method comprises the following steps: S1. Preparation of detection material: heating and solidifying the fluorescent substance and the carrier into a gel, and cutting into sheets to obtain the detection material; The fluorescent material used is zinc oxide quantum dots. The preparation of zinc oxide quantum dots ZnO QD with an average diameter of 4.3 nm is as follows: Zn(Ac)2·2H2O was dissolved in boiling anhydrous ethanol and deionized water was added dropwise; The emission wavelength of ZnO QDs was adjusted by adding deionized water, which was then refluxed to 90 °C under vigorous stirring, and the reaction mixture was cooled to 0 °C; Under ultrasonication, LiOH·H2O powder was added to the stock solution; The stock solution was treated with continuous ultrasound for 3 h until the zinc oxide colloidal solution became transparent; Finally, n-hexane was added to the clarified ZnO ethanol solution with a volume ratio of ethanol to n-hexane of 1:3, and the solution was centrifuged at 1500 rpm. The supernatant was removed, and the same volume of anhydrous ethanol was added to redisperse the ZnO precipitate. Preparation of ZnO QD-PDMS composite: The purified zinc oxide quantum dot colloid was diluted 5-fold with anhydrous ethanol. 2 ml of PDMS prepolymer component A was mixed with the volume ratio of ZnO ethanol solution to PDMS prepolymer component A = 1:10 and ultrasonicated at room temperature for 4 h. PDMS prepolymer component B was added and cross-linked, and mixed thoroughly with the PDMS A / ZnO mixture. The test material was placed in a drying oven and controlled at 70°C. After heating and curing for 40 minutes, the test material was removed from the drying oven, the lid was opened, and the test material, which had dried into a gel-like state, was cut into 2 × 20 mm × 15 mm pieces and taken out to obtain the test material containing fluorescent nano-zinc oxide quantum dots. S2. Take the test materials as blank samples and test samples respectively. Seal the test samples and food, and seal the blank samples. Before testing, take out the test samples and blank samples and place them at both ends of the test material rack respectively. S3. Place the color-changing visualized food corruption detection device in a dark environment, turn on the switch, and simultaneously illuminate the blank sample and the test sample with the ultraviolet light source. Collect images and extract the green fluorescence intensity, which is converted into a green fluorescence intensity-time curve. The corrosive gases are sulfides or amine compounds.

2. The method for detecting food spoilage by color change visualization according to claim 1, characterized in that: The housing (1) fixes a switch via a switch fixing hole (12), and the switch is connected to a power module (5).

3. The method for detecting food spoilage by color change visualization according to claim 1, characterized in that: The housing (1) has a battery fixing slot (13) for fixing the battery, and the battery is connected to the power module (5).

4. The method for detecting food spoilage by color change visualization according to claim 1, characterized in that: It also includes a light source bracket (6) and a power module bracket (7), wherein the ultraviolet light source (2) is arranged on the light source bracket (6), and the power module (5) is arranged on the power module bracket (7).

5. The method for detecting food spoilage by color change visualization according to claim 1, characterized in that: The housing (1) is provided with an adhesive fixing groove (14).

6. The method for detecting food spoilage by color change visualization according to claim 1, characterized in that: A soft magnetic material frame (17) is provided between the shell cover (15) and the side plate (16) of the shell (1), and soft magnetic material is placed on the soft magnetic material frame (17).

7. The method for detecting food spoilage by color change visualization according to claim 6, characterized in that: In step S2, two pieces of test material are cut; one piece is exposed to the corrosive gas, and the other piece is not exposed to the corrosive gas. The test material not exposed to the corrosive gas is the blank sample, and the test material exposed to the corrosive gas is the test sample. The blank sample is placed in a sealed bag and sealed. The test sample is attached to the surface of the food and placed in a sealed bag together with the food and sealed. The blank sample and the test sample are stored under the same conditions. Use food spoilage detection equipment to test blank samples and test samples; During the test, first open the shell cover of the food corruption detection device, take out the test sample and blank sample respectively, insert the blank sample into the left side of the test material rack, and insert the test sample into the right side of the test material rack, and then install the shell cover back into the device.

8. The method for detecting food spoilage by color change visualization according to claim 1, characterized in that: The fluorescent substance used in step S1 is nano ZnCeS; the nano ZnCeS is prepared as follows: Add 0.02g of fluorescent nano-ZnCeS and 20g of plastic precursor solution PDMS into a clean container; Stir the contents of the container evenly, pour into a mold with a diameter of 20 mm to form a liquid surface with a thickness of 2 mm, and cover the mold with a lid; Move the mold into a drying oven, control the temperature at 75°C, heat and cure for 30 minutes, then take it out; The mold was taken out of the drying oven, the lid was opened, and the detection material that had been dried into a gel state was cut into 2×20 mm×15 mm pieces and taken out to obtain the detection material containing fluorescent nano-ZnCeS.

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