Oxidation indication label for detecting processed meat products as well as preparation method and application of oxidation indication label

Abstract

The invention discloses an oxidation indication label for detecting processed meat products and preparation and application of the oxidation indication label, the oxidation indication label is made of a nanofiber membrane, and the nanofiber membrane is prepared from a spinning solution through electrostatic spinning; the spinning solution comprises a film-forming substrate, anthocyanin and hydroxylamine salt. The invention also provides a preparation method and application of the detection kit for processing meat products. According to the method, the decay front end of the processed meat product is accurately monitored, and the oxidation level of the processed meat product is divided by capturing and developing aldehydes in the oxidation stage of the processed meat product; the invention has the advantages of obvious discoloration, high stability, simple preparation method, low cost, safety, high efficiency and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of nano indicating label in food field.More specifically, the present application relates to an oxidation indicating label for detecting processed meat product and a detection method. BACKGROUND

[0002] Processed meat refers to any meat that is salted, dried, fermented, smoked or otherwise treated to enhance flavor or extend shelf life. Processed meat products such as ham, sausage, dried fish and bacon have high salt content, low water activity and slow microbial growth. Therefore, the shelf life of such processed meat products is mainly affected by the degree of lipid and protein oxidation. Studies have shown that unsaturated fatty acids in meat are unstable and easily oxidized and degraded when exposed to oxygen or heat, forming various volatile aldehydes. At the same time, proteins are easily oxidized during processing and storage, leading to the decomposition of amino acid residues and the formation of aldehydes. These aldehyde substances bring unique aroma and flavor to meat products and improve the overall sensory quality of meat products. However, excessive aldehyde substances can mask the unique flavor of processed meat products and cause the appearance of undesirable odors. Therefore, it is very important to quickly, sensitively and real-time monitor the degree of oxidation of processed meat products during production and flow. In recent years, visual indicating labels have good application prospects in the detection of food freshness. However, the detection mechanism of such indicating labels is designed based on the pH change caused by physical, chemical and biological changes in meat, and is not suitable for monitoring the degree of oxidation of processed meat products. In order to ensure the safety of processed meat products, it is urgent to develop an oxidation indicating label that can be used for real-time monitoring of the degree of oxidation of processed meat products, with low cost and high sensitivity. SUMMARY

[0003] An object of the present application is to solve at least the above problems and to provide at least the advantages to be described later.

[0004] Another object of the present application is to provide an oxidation indicating label for detecting processed meat product, which can accurately monitor the front end of spoilage of processed meat product, and divide the oxidation level of processed meat product by capturing and developing aldehyde substances in the oxidation stage of processed meat product; It has the advantages of obvious color change, high stability, simple preparation method, low cost, high safety and efficiency, etc.

[0005] In order to achieve the objects and other advantages according to the present application, an oxidation indicating label for processed meat detection is provided, which is made of a nanofiber membrane prepared by electrospinning of a spinning solution; the spinning solution comprises a film-forming base, anthocyanin and hydroxylamine salt. The oxidation indicating label according to the present application uses a low-cost and high-performance film-forming base such as polyvinyl alcohol (PVA), uses anthocyanin (BA) as a color developing agent, and uses hydroxylamine sulfate (HAS) as an aldehyde recognizing agent. The HAS in the oxidation indicating label can react with aldehydes released by oxidation of the processed meat to form aldehyde oxime and sulfuric acid, resulting in a decrease in the pH value in the storage environment. With the change of the pH value, the structure of BA in the oxidation indicating label changes, so that the oxidation indicating label shows a significant color change. The inventors have found that after the oxidation indicating label is placed, the release of sulfuric acid in the environment is positively correlated with the content of hexanal, and within the range of 50-1000 ppm, with the increase of the aldehyde concentration, the color of the oxidation indicating label gradually deepens, for example, from white to light pink and then to rose pink.

[0006] Preferably, the film-forming base is one of polyvinyl alcohol, gelatin, polylactic acid, polycaprolactone, poly-lactic-glycolic acid copolymer, polyvinylpyrrolidone or polyethylene oxide; the film-forming base requires high biocompatibility and can be prepared into a film-forming material with electrospun fibers having a diameter of 500-2000 nm.

[0007] The anthocyanin is blueberry anthocyanin or grape seed anthocyanin;

[0008] The hydroxylamine salt is one of hydroxylamine sulfate, hydroxylamine phosphate, hydroxylamine nitrate or hydroxylamine perchlorate. The oxidation indicating label according to the present application adds hydroxylamine salt to the electrospinning solution, so that it can react with aldehyde substances produced in the oxidation process of the processed meat, in addition to producing aldehyde oxime, there will also be acidic products, which can cause the pH value in the storage environment to decrease. With the change of the pH value, the structure of BA in the oxidation indicating label changes, so that the oxidation indicating label shows a significant color change.

[0009] Preferably, the film-forming base is polyvinyl alcohol PVA; the anthocyanin is blueberry anthocyanin BA; and the hydroxylamine salt is hydroxylamine sulfate HAS. Considering the material cost, processing difficulty and storage and stability of the hydroxylamine salt, the present application preferably uses polyvinyl alcohol PVA, blueberry anthocyanin BA and hydroxylamine sulfate HAS to prepare a PVA-BA-HAS membrane, and further prepare a PVA-BA-HAS oxidation indicating label.

[0010] Preferably, the weight ratio of the film-forming base, anthocyanin and hydroxylamine salt in the spinning solution is (15-20):(0.2-0.5):1.

[0011] Preferably, the weight ratio of the film-forming matrix, anthocyanin and hydroxylamine salt in the spinning solution is 18:0.2:1.

[0012] The application also provides a preparation method of the oxidation indicating label for detecting processed meat products, comprising the following steps:

[0013] A polyvinyl alcohol-anthocyanin-hydroxylamine sulfate (PVA-BA-HAS) spinning solution with a concentration of 7-15% (W / V) is prepared;

[0014] The polyvinyl alcohol-anthocyanin-hydroxylamine sulfate (PVA-BA-HAS) spinning solution is taken, a metal needle is installed, and the spinning solution is placed in a push pump of an electrospinning machine; electrospinning is performed to prepare a film;

[0015] Preferably, the electrospinning parameters are as follows: voltage 20 kV; feeding speed 0.5 mL·h -1 ; receiving distance 10 cm; temperature 25℃; humidity 58% rh.

[0016] Preferably, the preparation method further comprises: placing the prepared electrospinning film in a constant temperature oven at 30℃ to dry to constant weight; then, the electrospinning film is cut into pieces to prepare the oxidation indicating label. The oxidation indicating label is, for example, a circular piece, a square piece or a hollow circular piece, and can also be a piece of hollow butterfly shape.

[0017] The application also provides application of the oxidation indicating label for detecting processed meat products in detection of processed meat products. The oxidation indicating label is used for detecting the oxidation degree of processed meat products.

[0018] Preferably, the processed meat product is heated in a constant temperature oven at 60±1℃ for 0h, 12h, 24h, 48h, 60h and 72h to obtain processed meat products with different oxidation degrees; the processed meat products with different oxidation degrees are placed in a sealed space together with the oxidation indicating label, and the color change of the oxidation indicating label is observed, recorded and analyzed.

[0019] Preferably, the color of the oxidation indicating label changes from light to dark, which indicates that the oxidation degree of the processed meat product changes from low to high.

[0020] The application at least comprises the following beneficial effects: the oxidation indicating label for processing meat product of the application breaks through to recognize and detect aldehydes at the front end of processing meat product corruption, and through the capture and color development of aldehyde substances in the oxidation process of the processing meat product, the oxidation degree of the processing meat product is accurately monitored, the food safety monitoring is applied to the more front end of processing, transportation and storage of the processing meat product, which is more beneficial to the quality monitoring of the processing meat product, and further improves the food safety of the processing meat product.

[0021] Other advantages, objects, and features of the application will be apparent from the following specification, and will be appreciated by those skilled in the art. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The scanning electron microscope images of the oxidation indicating label for processing meat product detection and each label in each comparative example according to the application are provided for the implementation of the application;

[0023] Figure 2 The average fiber diameter distribution graph of the label according to the application and the comparative example is provided;

[0024] Figure 3 The infrared spectrum graph of the oxidation indicating label for processing meat product detection and each label in each comparative example according to the application is provided for the implementation of the application;

[0025] Figure 4 The XRD spectrum graph of the oxidation indicating label for processing meat product detection and each label in each comparative example according to the application is provided for the implementation of the application;

[0026] Figure 5 The X-ray photoelectron spectrogram of the oxidation indicating label for processing meat product detection and each label in each comparative example according to the application is provided for the implementation of the application;

[0027] Figure 6 The thermogravimetric (TG) curve graph and the thermal weight differential (DTG) curve graph of the oxidation indicating label for processing meat product detection and each label in each comparative example according to the application are provided for the implementation of the application;

[0028] Figure 7 The contact angle diagram of the oxidation indicating label for processing meat product detection and each label in each comparative example according to the application is provided for the implementation of the application;

[0029] Figure 8Cell culture pictures and cell proliferation rate columnar diagrams of each label in the oxidation indicating label for processed meat detection and each pair of the present application;

[0030] Figure 9 Stability photos of each label in the oxidation indicating label for processed meat detection and each pair of the present application;

[0031] Figure 10 Colorimetric response diagrams of each label in the oxidation indicating label for processed meat detection and each pair of the present application in humidity, sealed air and different concentrations of gaseous hexanal;

[0032] Figure 11 Color change photos of the oxidation degree detection of processed meat by the oxidation indicating label for processed meat detection of the present application;

[0033] Figure 12 Columnar diagram of label ΔE value when the oxidation degree of processed meat is detected by the oxidation indicating label for processed meat detection of the present application. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement the present application according to the description.

[0035] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0036] The present application provides an oxidation indicating label for processed meat detection, which uses low-cost and excellent performance polyvinyl alcohol (PVA) as a film-forming matrix, blueberry anthocyanin (BA) as a color developing agent, and hydroxylamine sulfate (HAS) as an aldehyde recognition agent. A PVA-BA-HAS film is prepared by electrospinning technology. After drying the PVA-BA-HAS film, it can be cut into a PVA-BA-HAS indicating label.

[0037] In one embodiment, the oxidation indicating label for processed meat detection of the present application uses polyvinylpyrrolidone PVP as a film-forming matrix, grape seed anthocyanin as a color developing agent, and hydroxylamine sulfate HAS as an aldehyde recognition agent. A PVP-BA-HAS film is prepared by electrospinning technology. After drying the PVP-BA-HAS film, it can be cut into a PVP-BA-HAS indicating label.

[0038] The application provides a preparation method of the oxidation indicating label for detecting processed meat products, wherein anthocyanins and hydroxylamine sulfate are added into a PVA solution, an electrospinning solution is prepared, and then a PVA-BA-HAS film is prepared by using an electrospinning instrument, so as to prepare the oxidation indicating label.

[0039] Example 1

[0040] The preparation method of the oxidation indicating label for detecting processed meat products comprises the following steps:

[0041] 10 g of PVA is dissolved in 100 mL of distilled water, stirred in a 75℃ water bath for 8 h, and a 10% (W / V) PVA solution is obtained.

[0042] 20 mg of BA is dispersed in 20 mL of deionized water, ultrasonically treated for 30 min, then 100 mg of HAS is added and ultrasonically treated for 10 min, then 18 mL of 10% PVA solution is added, magnetically stirred for 1 h, and ultrasonically degassed, and finally a 9% (W / V) PVA-BA-HAS spinning solution is obtained.

[0043] 5 mL of the spinning solution is taken by using a syringe, a metal needle is installed, and the needle is placed into a push pump of an electrospinning machine. The electrospinning parameters are set as follows: voltage 20 kV; feeding speed 0.5 mL·h -1 ; receiving distance 10 cm; temperature 25℃; humidity 58% rh, and a PVA-BA-HAS oxidation indicating label is prepared.

[0044] Comparative Example 1

[0045] 10 g of PVA is dissolved in 100 mL of distilled water, stirred in a 75℃ water bath for 8 h, and a 10% (W / V) PVA solution is obtained.

[0046] 20 mg of BA is dispersed in 20 mL of deionized water, ultrasonically treated for 30 min, then 18 mL of 10%

[0047] PVA solution is added, magnetically stirred for 1 h, and ultrasonically degassed, and finally a 9% (W / V) PVA-BA spinning solution is obtained.

[0048] 5 mL of the spinning solution is taken by using a syringe, a metal needle is installed, and the needle is placed into a push pump of an electrospinning machine. The electrospinning parameters are set as follows: voltage 20 kV; feeding speed 0.5 mL·h -1 ; receiving distance 10 cm; temperature 25℃; humidity 58% rh, and a PVA-BA indicating label is prepared.

[0049] Comparative Example 2

[0050] Take 10g PVA dissolved in 100mL distilled water, stirring in 75℃ water bath for 8h, to obtain 10%(W / V) PVA solution.

[0051] 5mL of the spinning solution was taken by a syringe, a metal needle was installed, and it was put into the electrostatic spinning machine push pump. The electrostatic spinning parameters were set as: voltage 20kV; feeding speed 0.5mL·h -1 ; receiving distance 10cm; temperature 25℃; humidity 58%rh, to prepare PVA film.

[0052] The application also provides a detection method for the oxidation degree of the processed meat product based on the oxidation indicating label for processing meat product detection, which specifically comprises: according to the Schall oven test, the processed meat product such as Cantonese sausage is placed in a 60±1℃ constant temperature box for 0h, 12h, 24h, 48h and 72h, to obtain Cantonese sausages with different oxidation degrees, the PVA-BA-HAS oxidation indicating label is cut into a hollow butterfly shape and fixed above a culture dish, the color change of the label is recorded and analyzed. The color of the oxidation indicating label gradually deepens with the delay of the oxidation time, which indicates that the oxidation degree of the processed meat product deepens in turn.

[0053] The application carries out characterization and verification test on the PVA-BA-HAS oxidation indicating label prepared in Example 1.

[0054] 1. Characterization of the PVA-BA-HAS oxidation indicating label

[0055] 1) Scanning electron microscope (SEM)

[0056] The PVA-BA-HAS film prepared in Example 1, the PVA film prepared in Comparative Example 1 and the PVA-BA film prepared in Comparative Example 2 are respectively fixed on a glass slide, dried and then fixed on a sample stage, and the surface morphology thereof is observed by using SEM, and the results are shown in Figures 1-2 . Among them, the SEM electron microscope parameter settings are: EHT=10kV, MAG=5-10kX, vacuum degree <6×10 -4 Pa.

[0057] As shown in Figure 1 , the microstructure of the oxidation label is evaluated by SEM. The PVA film has a smooth, uniform and continuous structure Figure 1 A), and the average fiber diameter is 98.68±37.24nm Figure 2 A). Compared with the PVA film, the fiber morphology of the PVA-BA film shows higher transparency Figure 1 B). At the same time, the addition of BA leads to a significant increase in the average fiber diameter, reaching 126.21±24.14nm Figure 2B). Since BA can increase the viscosity of the spinning solution, and the increase in viscosity can enhance chain entanglement, thus increasing the tensile strength of the fiber during the spinning process, resulting in an increase in fiber diameter. In Figure 2 B, a slight fiber crosslinking was observed due to the formation of intermolecular hydrogen bonds between the -H groups in BA and the hydroxyl groups in PVA. With the addition of HAS, the average diameter and viscosity of the PVA-BA-HAS spinning solution decreased Figure 1 C, Figure 2 C), which is attributed to the hygroscopic nature of HAS. The decrease in viscosity hinders the ductility of the fiber, resulting in a decrease in fiber diameter. It is worth noting that PVA-BA fibers exhibit a beading phenomenon in terms of surface morphology, while this feature was not observed in PVA-BA-HAS fibers Figure 2 C). This is due to the formation of a well-organized hydrogen bond network, thus enhancing the interfacial activity and surface tension.

[0058] 2) Fourier Transform Infrared Spectroscopy (FTIR)

[0059] The surface groups of the PVA-BA-HAS oxidation indicator label prepared in Example 1, the PVA film prepared in Comparative Example 1, and the PVA-BA film prepared in Comparative Example 2 were analyzed by Fourier Transform Infrared Spectroscopy (FTIR), and the resulting infrared spectra are shown in Figure 3 . Among them, the spectral resolution is 2 cm -1 , and the wave number range of 500-4000 cm -1 is scanned 32 times.

[0060] As shown in Figure 3 , in the spectrum of the PVA film, the wide bands at 3286 cm -1 and 2913 cm -1 correspond to O-H stretching vibration and C-H bending, respectively. The peaks at 1414 cm -1 and 1083 cm -1 are C-H bending vibration and C-O stretching vibration, and the peak at 839 cm -1 is the surface bending vibration of C=C. Compared with the PVA film, no additional peaks were observed in the spectrum of the PVA-BA film. It is worth noting that after the introduction of BA, the peak intensity at 3286 cm -1 and 1083 cm -1 increased, which may be related to the formation of adjacent substitutions or any kind of bond within the anthocyanin structure. An outstanding absorption peak (1548 cm -1 ) was observed in the spectrum of the PVA-BA-HAS film, which is related to the bending vibration of N-H, indicating the successful introduction of amino groups.

[0061] 3) X-ray diffraction (XRD)

[0062] The PVA-BA-HAS film prepared in Example 1 was cut into a circle with a diameter of 2 cm and fixed on a sample holder, and the crystal structure of the PVA-BA-HAS oxidation indicator label was analyzed by XRD. The PVA film and PVA-BA film prepared in Comparative Example 1 were also cut into a circle with a diameter of 2 cm and fixed on a sample holder, and the crystal structure thereof was analyzed by XRD, and the results are shown in Figure 4 . Among them, the XRD parameters are set as follows: scanning range 2θ = 5-85°, scanning voltage 20 kV, scanning current 5 mA, Kα Scanning rate 4° min -1 , step width 0.02°.

[0063] As shown in Figure 4 , the PVA film was observed to have a clear diffraction peak at 18.64°, which is attributed to the semi-crystalline property of PVA, caused by the rich hydrogen bonds in the intermolecular stacking of polymer chains. After adding BA, the diffraction peak intensity of the PVA-BA film was slightly reduced. This phenomenon is due to the interaction between the cationic nature of the pyran ring in BA and the many hydroxyl groups (-OH) in PVA, resulting in a decrease in crystallinity. With the addition of HAS, the hydrogen bond interaction between PVA, BA and HAS molecules is enhanced, resulting in a decrease in the intensity of the crystalline region (2θ = 19.61°).

[0064] 4) X-ray photoelectron spectroscopy (XPS)

[0065] The PVA-BA-HAS oxidation indicator label prepared in Example 1 and the PVA-BA label prepared in Comparative Example 1 were fixed on a sample holder, and a monochromatic X-ray source Al Kα was used as an excitation source with an excitation voltage of 1487 eV to measure the binding energy of C1s at 284 eV for calibration. The elemental composition, content and chemical bond state of the PVA-BA-HAS oxidation indicator label and the PVA-BA label were determined by XPS, and the results are shown in Figure 5 .

[0066] As shown in Figure 5 , in the C1s spectrum of the PVA-BA label, Figure 5 A), the peaks at 281.02 and 282.15 eV correspond to C-C and C-O bonds. The O1s spectrum of the PVA-BA label shows that there are characteristic peaks at 529.15 eV and 533.47 eV, corresponding to O 2 - and C-O bonds, Figure 5 B), respectively. With the addition of HAS, the binding energy of C-C bond increased to 281.80 eV in the C1s spectrum, and that of C-O bond increased to 284.61 eV Figure 5C). This shift is attributed to the electron-withdrawing effect of the S element in HAS, which causes a redistribution of the electron density around the C atoms in PVA and BA. In the O 1s spectrum, a peak at 534.48 eV is observed, which is related to the O-H bond Figure 5 D). This peak is mainly attributed to the reaction between the hydroxylamine group in HAS and the oxygen atoms in the PVA-BA tag, which is consistent with the results of the FTIR analysis Figure 3 ). The N 1s spectrum of the PVA-BA-HAS oxidation indicator tag is shown in Fig. Figure 5 E, where the peak at 401.20 eV is related to the -NH2 bond. The above peak is related to the addition of HAS in the PVA-BA-HAS oxidation indicator tag, as confirmed by the S 2p spectrum Figure 5 F). These results indicate that the PVA-BA-HAS oxidation indicator tag has been successfully synthesized.

[0067] 5) Thermogravimetric analysis

[0068] 10 ± 0.1 mg of the PVA-BA-HAS oxidation indicator tag prepared in Example 1, the PVA film prepared in Comparative Example 1 and the PVA-BA film prepared in Comparative Example 2 were weighed into crucibles, respectively, and the thermal stability was analyzed using a TGA instrument, where the N2flow rate was 50 mL·min -1 , and the test temperature of the thermogravimetric analyzer was 0-600 °C, with a heating rate of 10 °C·min -1 . The results are shown in Fig. Figure 6 . Figure 6 , where a represents the PVA film, b represents the PVA-BA film, and c represents the PVA-BA-HAS oxidation indicator tag.

[0069] As shown in Fig. Figure 6 A, the first stage represents the evaporation of water in the PVA film. Here, the PVA film and the PVA-BA film lost about 13% of their weight at 257.24 °C, while the PVA-BA-HAS oxidation indicator tag lost 13% at 194.15 °C. In the second stage, the thermal decomposition of the PVA film and the PVA-BA film mainly occurred between 250 and 320 °C, resulting in a mass loss of about 70%, which is due to the intramolecular and intermolecular dehydration reactions of the hydroxyl groups in the PVA molecular structure. At the same time, the thermal decomposition rate increased significantly at 302.87 °C Figure 6curve a and curve b) in B. With the addition of HAS, the decomposition temperature of PVA-BA-HAS oxidation indicating label (curve c) was observed to increase in the range of 254 to 455 °C (second stage), resulting in a mass loss of about 74%. The DTG curve indicated that the maximum thermal decomposition rate of PVA-BA-HAS oxidation indicating label occurred at 438.62 °C. This phenomenon was attributed to the fact that HAS promoted the formation of a more compact and stable network structure between PVA molecular chains, thus enhancing the thermal stability. The third stage was the last stage of thermal decomposition, and the thermal decomposition temperatures of 345.35 °C, 429.45 °C and 475.49 °C were observed, which was related to the by-products formed during the thermal degradation of PVA film. Compared with PVA film and PVA-BA film, PVA-BA-HAS oxidation indicating label showed excellent thermal stability. This was mainly attributed to the hydrophilicity of HAS, which could maintain hydration in a high temperature environment and delay the thermal decomposition of the oxidation label.

[0070] 2. Stability test of the PVA-BA-HAS oxidation indicating label

[0071] The contact angle experiment was used to evaluate the hydrophilic and hydrophobic properties of the films, and the results are shown in Figure 7 . Generally, when the contact angle is more than 65°, the film surface is considered to be hydrophobic. As shown in Figure 7 A, the contact angle of PVA film was 88±1°, which indicated that its hydrophilic property was moderate. As shown in Figure 7 B, the contact angle of PVA-BA film increased slightly (90±1°) due to the addition of BA. This was attributed to the additional -OH groups provided by BA, which promoted the formation of hydrogen bonds and reduced the adhesion of water molecules on the film surface. As shown in Figure 7 C, with the addition of HAS, the contact angle of PVA-BA-HAS oxidation indicating label decreased by 10°, which was attributed to the high hydrophilicity of HAS. However, there was no significant difference in the hydrophobicity of the surface of the oxidation label, which indicated that the label could maintain its form to ensure stable detection in a highly humid and closed environment.

[0072] 3. Biocompatibility test of the PVA-BA-HAS oxidation indicating label

[0073] The cytotoxicity of the oxidation label was evaluated by L929 cells, and the results are shown in Figure 8The specific steps include: the experimental group: L929 cells were cultured in T25 culture flask added with DEME medium. The medium was removed and the cells were washed with PBS, and the prepared PVA-BA-HAS oxidation indicating label was cultured with L929 cells for 24 h, and finally 10 μL CCK-8 solution was added in each well and continuously cultured for 4 h. The blank group: L929 cells were cultured in T25 culture flask added with DEME medium. The medium was removed and the cells were washed with PBS, and the L929 cells were cultured for 24 h, and finally 10 μL CCK-8 solution was added in each well and continuously cultured for 4 h. Among them, Figure 8 A shows the image of the blank L929 cell group without adding the PVA-BA-HAS oxidation indicating label; Figure 8 B shows the image of the L929 cell group added with the PVA-BA-HAS oxidation indicating label; Figure 8 C shows the column chart of the cell proliferation rate of the blank group and the experimental group.

[0074] Compared with the blank group ( Figure 8 A), the L929 cells cultured with the PVA-BA-HAS oxidation indicating label showed high cell density, and no obvious cell adhesion or separation, apoptosis or necrosis ( Figure 8 B) occurred. In addition, as shown in Figure 8 C, the cell proliferation rate of the experimental group was similar to that of the blank group ( Figure 8 C), indicating that the PVA-BA-HAS oxidation indicating label had no cytotoxic effect. The P value obtained by statistical analysis was 0.1718 x 10-20, which was significantly lower than the traditional threshold value 0.05. These results showed that the PVA-BA-HAS oxidation indicating label had biocompatibility and could be used for food packaging.

[0075] 4. Anti-interference analysis of oxidation indicating label

[0076] The PVA-BA-HAS oxidation indicating label prepared in Example 1 was cut into a hollow butterfly shape with a diameter of 4 x 4 cm and fixed on the top of a culture dish, which was exposed to water and closed air, and the color change of the label image was monitored, with a time range of 0-10 min. The results are shown in Figure 9 As shown in Figure 9 , no color change of the PVA-BA-HAS oxidation indicating label was observed during storage. At the same time, the anti-interference of the PVA-BA-HAS oxidation label was evaluated under the conditions of humidity and closed air, respectively. The results showed that the oxidation indicating label showed excellent stability and would not change color.

[0077] 5. Sensitivity analysis of oxidation indicating label

[0078] The PVA-BA-HAS oxidative indicator tag prepared in Example 1 and the PVA-BA tag prepared in Comparative Example 2 were cut into hollow butterfly shapes with a diameter of 4 x 4 cm, fixed on the top wall of a culture dish at room temperature, and exposed to gaseous hexanal with different concentrations (50 ppm, 100 ppm, 350 ppm, 500 ppm, and 1000 ppm). The color change of the tag image was monitored in the time range of 0-10 min, and the results are shown in Figure 10 .

[0079] wherein the concentration of hexanal is calculated according to the following formula:

[0080]

[0081] wherein C represents the concentration of hexanal (ppm), p represents the density of hexanal (g mL-1), V S represents the volume of hexanal (μL), T represents the test temperature in kelvin, V represents the volume of the container (L), and M S represents the molecular weight of hexanal (g mol -1 ).

[0082] The color information of the oxidative indicator tag was recorded at room temperature using a smart phone, and the change in the ΔΕ value of the oxidative indicator tag was measured using a CM-5 colorimeter. The ΔΕ value is calculated according to the following formula:

[0083]

[0084] wherein L, a, and b represent the initial test values of the oxidative indicator tag, and L*, a*, and b* represent the test values of the oxidative indicator tag after discoloration.

[0085] Figure 10 (A) shows the color response of the PVA-BA film in humidity, sealed air, and gaseous hexanal solutions with different concentrations; Figure 10 (B) shows the colorimetric response of the PVA-BA-HAS oxidative indicator tag in humidity, sealed air, and gaseous hexanal solutions with different concentrations. Since hexanal is ubiquitous in processed meat products and has been proven to be an indicator of lipid oxidation, hexanal was selected as a representative aldehyde. As shown in Figure 10 (A), the absence of a coupling agent (HAS) prevents any interaction from occurring, and no color change is observed in the PVA-BA film during storage. In solutions containing different concentrations of hexanal, the PVA-BA film does not change color. As shown in Figure 10 (B), the PVA-BA-HAS oxidative tag described in the present application shows a clear transition from light pink to rose pink, which can be directly detected by the naked eye or a digital camera.

[0086] Example 2

[0087] The method for detecting the degree of oxidation of processed meat products using the oxidation indicator label of the present invention includes: according to the Schall oven test, six groups of equal amounts of sausages were placed in an oven at 60±1℃ for 0h, 12h, 24h, 48h, 60h, and 72h respectively to obtain sausages with different degrees of oxidation. The PVA-BA-HAS oxidation indicator label prepared in Example 1 was then placed in a petri dish along with the six groups of sausages. The color change of the PVA-BA-HAS oxidation indicator label was observed and recorded, and its ΔE value was calculated. The results are shown in […]. Figure 11 and Figure 12 .

[0088] like Figure 11 As shown, the PVA-BA-HAS oxidation indicator label exhibits different colors at different stages of sausage oxidation. In the initial stage of sausage oxidation (first 12 hours), the color of the PVA-BA-HAS oxidation indicator label changes from white to light pink, with a ΔE value of 0.53 ± 0.12. Figure 12 As oxidation time increased, during the moderate oxidation stage of the sausage, the ΔE value of the PVA-BA-HAS oxidation indicator label increased to 25.51 ± 0.67. Figure 12 The color changed from light pink to bright pink. After 72 hours of storage, the sausages showed signs of oxidative deterioration; the color of the PVA-BA-HAS oxidation indicator label changed from bright pink to rose pink, and the ΔE value increased to 30.12 ± 0.81. Figure 12 ).

[0089] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An oxidation indicator label for detecting processed meat products, characterized in that, The oxidation indicator label is made of a nanofiber membrane, which is obtained by electrospinning a spinning solution; the spinning solution includes a film-forming matrix, anthocyanins, and hydroxylamine salts.

2. The oxidation indicator label for detecting processed meat products as described in claim 1, characterized in that, The film-forming matrix is ​​one of polyvinyl alcohol, gelatin, polylactic acid, polycaprolactone, polylactic acid-glycolic acid copolymer, polyvinylpyrrolidone, or polyethylene oxide; The anthocyanins are blueberry anthocyanins or grape seed anthocyanins; The hydroxylamine salt is one of hydroxylamine sulfate, hydroxylamine phosphate, hydroxylamine nitrate, or hydroxylamine perchlorate.

3. The oxidation indicator label for detecting processed meat products as described in claim 2, characterized in that, The film-forming matrix is ​​polyvinyl alcohol; the anthocyanin is blueberry anthocyanin; and the hydroxylamine salt is hydroxylamine sulfate.

4. The oxidation indicator label for detecting processed meat products as described in claim 3, characterized in that, The weight ratio of the film-forming matrix, anthocyanin and hydroxylamine salt in the spinning solution is (15-20):(0.2-0.5):

1.

5. The oxidation indicator label for detecting processed meat products as described in claim 4, characterized in that, The weight ratio of the film-forming matrix, anthocyanin and hydroxylamine salt in the spinning solution is 18:0.2:

1.

6. The method for preparing an oxidation indicator label for detecting processed meat products as described in any one of claims 1-5, characterized in that, Includes the following steps: Prepare a polyvinyl alcohol-anthocyanin-hydroxylamine sulfate (PVA-BA-HAS) spinning solution with a concentration of 7-15% (W / V); The polyvinyl alcohol-anthocyanin-hydroxylamine sulfate (PVA-BA-HAS) spinning solution is taken out, a metal needle is installed, and it is placed into the feed pump of the electrospinning machine; electrospinning and film formation are then performed. The electrospinning parameters were: voltage 20kV; feed rate 0.5mL·h. -1 ; Receiving distance 10cm; Temperature 25℃; Humidity 58% RH.

7. The preparation method according to claim 6, characterized in that, Also includes: The prepared electrospun film was placed in a 30°C constant temperature oven and dried to constant weight; then, the electrospun film was cut into sheets to obtain oxidation indicator labels.

8. The application of the oxidation indicator label for processing meat product testing as described in any one of claims 1-5 in the testing of processed meat products, characterized in that, The oxidation indicator label is used to detect the degree of oxidation in processed meat products.

9. The application as described in claim 8, characterized in that, The detection steps include: placing the processed meat products in a constant temperature chamber at 60±1℃ and heating for 0h, 12h, 24h, 48h, 60h and 72h to obtain processed meat products with different degrees of oxidation; placing the processed meat products with different degrees of oxidation together with the oxidation indicator label in a sealed space; and observing, recording and analyzing the color change of the oxidation indicator label.

10. The application as described in claim 9, characterized in that, The color of the oxidation indicator label changes from light to dark, indicating that the degree of oxidation of the processed meat product changes from low to high.

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