Pseudosciaena crocea preservation method through blue light-chlorine dioxide combined treatment

Abstract

The invention belongs to the technical field of aquatic product preservation, and provides a large yellow croaker preservation method by blue light-chlorine dioxide (ClO2) combined treatment. The method comprises the following steps: (1) preparing a solution containing chlorine dioxide by using pure water, freezing into ice blocks, and crushing to obtain ClO2 crushed ice; (2) putting the back-opened pseudosciaena crocea into a foam box filled with ClO2 crushed ice, and completely covering the surface of the pseudosciaena crocea body with the ClO2 crushed ice; (3) transferring the foam box into a refrigerator with LED blue light at 0-4 DEG C for storage, and irradiating the back-opened pseudosciaena crocea in the foam box with the LED blue light; the ClO2 crushed ice covering the surfaces of the fish bodies is regularly replaced in the storage period. According to the method, the storage period of the pseudosciaena crocea is effectively prolonged and the eating quality of the pseudosciaena crocea is improved by utilizing a blue light-ClO2 combined treatment method.

Description

Technical Field

[0001] The present invention relates to the technical field of aquatic product preservation, and particularly to a preservation method for large yellow croaker by combined treatment of blue light and chlorine dioxide. Background Art

[0002] Large yellow croaker is an important economically cultured fish in the eastern coastal areas of China (such as Zhejiang and Fujian), and is widely popular due to its delicious taste and rich nutrition. However, due to the high content of moisture, protein and unsaturated fatty acids in fish meat, fresh large yellow croaker is extremely perishable, and is easily affected by endogenous enzymes and microorganisms after fishing, resulting in protein decomposition, rising pH and TVB-N values, and then generating peculiar smells, spoilage, and even causing foodborne diseases.

[0003] At present, the preservation methods of aquatic products mainly rely on low-temperature storage, combined with modified atmosphere packaging, irradiation, ultra-high pressure, addition of preservatives, etc., but the antibacterial effect is limited, and it is easy to affect the flavor of aquatic products and the problem of preservative residues. Therefore, it is necessary to develop efficient preservation technologies to extend the shelf life of large yellow croaker and ensure its quality and safety.

[0004] Chlorine dioxide (ClO2) is an A1-level highly efficient sterilant certified by the World Health Organization and the United States Department of Agriculture, which can kill pathogens such as bacteria and viruses, and is widely used in fields such as drinking water disinfection and food processing. Its mechanism of action includes destroying cell membranes, oxidizing substances inside cells (such as NADH), and damaging DNA structures, resulting in cell death. However, ClO2 gas is unstable and difficult to prepare and transport. Although ClO2 is approved as a safe disinfectant, when using a relatively high concentration of ClO2 alone, it is also necessary to consider its residue problem in fresh products and ready-to-eat foods.

[0005] Blue light sterilization technology utilizes blue light in the range of 400 - 480 nm, which causes endogenous porphyrin compounds in bacteria to produce reactive oxygen species (ROS) after absorbing blue light, and then destroys DNA, proteins and lipids, resulting in bacterial death. Blue light sterilization has broad-spectrum properties, can effectively inactivate drug-resistant bacteria (such as MRSA, Pseudomonas aeruginosa, Candida albicans, etc.), and causes less harm to mammalian cells, and is widely used in the fields of medical disinfection and food preservation. However, the effect of using blue light sterilization technology alone is affected by the characteristics of food matrix (such as protein content) and the formation of bacterial biofilms, and the penetration of blue light is limited, and its bactericidal effect is mainly aimed at surface microorganisms of foods. For some low-moisture foods that may also have internal microbial contamination, single blue light sterilization may not achieve the desired effect.

[0006] Therefore, it is particularly important to develop a combined technology that can not only make up for the limitations of single technologies, but also effectively extend the shelf life of large yellow croaker and maintain its quality. Summary of the Invention

[0007] To overcome the above-mentioned defects existing in the prior art, the present invention combines blue light treatment with chlorine dioxide treatment to provide a method for preserving large yellow croaker.

[0008] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions: The present invention provides a method for preserving large yellow croaker by combining blue light - chlorine dioxide (ClO2) treatment, including the following steps: (1) Prepare a chlorine dioxide-containing solution with pure water, freeze it into ice cubes and then crush them to obtain ClO2 crushed ice; (2) Put the gutted large yellow croaker into a foam box filled with ClO2 crushed ice so that the fish body surface is completely covered by the ClO2 crushed ice; (3) Transfer the foam box to a refrigerator at 0 - 4°C equipped with LED blue light for storage, and irradiate the gutted large yellow croaker in the foam box with LED blue light; during storage, regularly replace the ClO2 crushed ice covering the fish body surface.

[0009] Preferably, in step (1), the ClO2 concentration in the ClO2 crushed ice is 10 mg / L, and the size of the ClO2 crushed ice is 0.80 ± 0.20 cm 3 .

[0010] Preferably, in step (2), the preparation steps of the gutted large yellow croaker include: anatomize the fresh large yellow croaker, remove internal organs, fish head, fish tail, fish bones and other parts, leaving only the fish back muscle and the fish belly part; the weight of the fresh large yellow croaker is 480 ± 30 g per tail, and the average length of the fresh large yellow croaker is 28 ± 3 cm per tail.

[0011] Preferably, in step (2), the ice layer thickness of the ClO2 crushed ice covering the fish body surface is 3 - 4 cm.

[0012] Preferably, in step (3), the wavelength of the LED blue light is 405 nm.

[0013] Preferably, in step (3), the distance between the light source and the fish body is 20 cm.

[0014] Preferably, in step (3), the regular replacement is once every 20 hours.

[0015] Due to the adoption of the above scheme, the beneficial effects of the present invention are: Blue light - chlorine dioxide combined treatment can significantly extend the storage time of large yellow croaker, effectively avoiding the rapid oxidative degradation of proteins and the growth of microorganisms during the storage of large yellow croaker, inhibiting the activity of proteases, maintaining relatively low TVB - N values, pH values, and total colony counts, and being able to better maintain the integrity of the muscle tissue of large yellow croaker. The synergistic treatment technology of blue light and chlorine dioxide has opened up a new path for the medium - and long - term storage and preservation of aquatic products such as large yellow croaker, providing a more practical innovative solution for the field of aquatic product preservation. Brief Description of the Drawings

[0016] Figure 1 It is a graph showing the change in the total number of colonies of large yellow croaker samples during storage in each example and comparative example.

[0017] Figure 2 It is a graph showing the change in pH value of large yellow croaker samples during storage in each example and comparative example.

[0018] Figure 3 It is a graph showing the change in the content of volatile basic nitrogen (TVB - N) of large yellow croaker samples during storage in each example and comparative example.

[0019] Figure 4 It is a graph showing the change in thiobarbituric acid value (TBARS) of large yellow croaker samples during storage in each example and comparative example.

[0020] Figure 5 It is a graph showing the change in hardness of large yellow croaker samples during storage in each example and comparative example.

[0021] Figure 6 It is a graph showing the change in elasticity of large yellow croaker samples during storage in each example and comparative example.

[0022] Figure 7 It is a graph showing the change in chewiness of large yellow croaker samples during storage in each example and comparative example.

[0023] Figure 8 It is a graph showing the change in the optical microscope structure of large yellow croaker samples during storage in each example and comparative example.

[0024] Figure 9 It is a graph showing the change in the SEM microstructure of large yellow croaker samples during storage in each example and comparative example. Detailed Embodiments

[0025] The technical solutions provided by the present invention will be described in detail below in conjunction with examples, but they should not be construed as limiting the scope of protection of the present invention.

[0026] The fresh large yellow croakers in the present invention are all purchased from Minwei Food Co., Ltd., Ningde City, Fujian Province. After being caught at night by a sea - fishing boat, they are transported to Fuzhou by cold chain. The average weight is 480 ± 30 g per fish, and the average length is 28 ± 3 cm per fish.

[0027] The chlorine dioxide (ClO2) effervescent tablets in the present invention are purchased from Shandong Reneng Biotechnology Co., Ltd., and the product number is 20200407.

[0028] Example 1: A preservation method for large yellow croaker by combined treatment of blue light and chlorine dioxide is as follows: (1) Raw material pretreatment: After thawing the fresh large yellow croaker transported by cold chain, it is anatomically processed with a sterile knife to remove the internal organs, head, tail, fish bones and other parts of the large yellow croaker, leaving the back muscle and belly of the fish to obtain the split-back large yellow croaker.

[0029] (2) Preparation of ClO2 crushed ice: The ClO2 effervescent tablets are dissolved in pure water to prepare a solution with a ClO2 concentration of 10 mg / L, and frozen at -20 °C for 12 hours to form ice cubes, which are then crushed into pieces with a size of 0.80 ± 0.20 cm 3 to obtain ClO2 crushed ice.

[0030] (3) Put the split-back large yellow croaker into a foam box filled with ClO2 crushed ice, so that the surface of the fish body is completely covered by a ClO2 crushed ice layer with a thickness of 3 - 4 cm.

[0031] (4) Transfer the foam box to a 0 - 4 °C refrigerator equipped with LED blue light for storage, and irradiate the split-back large yellow croaker in the foam box with LED blue light with a wavelength of 405 nm. The distance between the light source and the fish body is 20 cm, and the blue light intensity at this distance is 0.538 mW / cm 2 ; During storage, the ClO2 crushed ice layer covering the surface of the fish body is replaced every 20 hours.

[0032] Example 2: A preservation method for large yellow croaker is as follows: (1) Raw material pretreatment: After thawing the fresh large yellow croaker transported by cold chain, it is anatomically processed with a sterile knife to remove the internal organs, head, tail, fish bones and other parts of the large yellow croaker, leaving the back muscle and belly of the fish to obtain the split-back large yellow croaker.

[0033] (2) Preparation of pure water crushed ice: Freeze pure water at -20 °C for 12 hours and then crush it into pieces with a size of 0.80 ± 0.20 cm 3 to obtain pure water crushed ice.

[0034] (3) Put the split-back large yellow croaker into a foam box filled with pure water crushed ice, so that the surface of the fish body is completely covered by a pure water crushed ice layer with a thickness of 3 - 4 cm.

[0035] (4) Transfer the foam box to a refrigerator at 0 - 4 °C equipped with LED blue light for storage, and irradiate the gutted large yellow croaker in the foam box with LED blue light at a wavelength of 405 nm. The distance between the light source and the fish body is 20 cm, and the blue light intensity at this distance is 0.538 mW / cm 2 ; During storage, replace the pure water crushed ice layer covering the fish body surface every 20 hours.

[0036] Example 3: A method for preserving large yellow croaker, the steps are as follows: (1) Raw material pretreatment: After thawing the fresh large yellow croaker transported by cold chain, use a sterile knife for dissection to remove the internal organs, head, tail, fish bones and other parts of the large yellow croaker, leaving the dorsal muscle and belly of the fish to obtain gutted large yellow croaker.

[0037] (2) Preparation of ClO2 crushed ice: Dissolve ClO2 effervescent tablets in pure water to prepare a solution with a ClO2 concentration of 10 mg / L, freeze it at -20 °C for 12 hours to make ice cubes, and then crush them into pieces with a size of 0.80 ± 0.20 cm 3 to obtain ClO2 crushed ice.

[0038] (3) Put the gutted large yellow croaker into a foam box filled with ClO2 crushed ice, so that the fish body surface is completely covered by a ClO2 crushed ice layer with a thickness of 3 - 4 cm.

[0039] (4) Transfer the foam box to a refrigerator at 0 - 4 °C for storage; during storage, replace the ClO2 crushed ice layer covering the fish body surface every 20 hours.

[0040] Comparative Example 1: A method for preserving large yellow croaker, the steps are as follows: (1) Raw material pretreatment: After thawing the fresh large yellow croaker transported by cold chain, use a sterile knife for dissection to remove the internal organs, head, tail, fish bones and other parts of the large yellow croaker, leaving the dorsal muscle and belly of the fish to obtain gutted large yellow croaker.

[0041] (2) Preparation of pure water crushed ice: Freeze pure water at -20 °C for 12 hours to make ice cubes, and then crush them into pieces with a size of 0.80 ± 0.20 cm 3 to obtain pure water crushed ice.

[0042] (3) Put the gutted large yellow croaker into a foam box filled with pure water crushed ice, so that the fish body surface is completely covered by a pure water crushed ice layer with a thickness of 3 - 4 cm.

[0043] (4) Transfer the foam box to a refrigerator at 0 - 4 °C for storage; during storage, replace the pure water crushed ice layer covering the fish body surface every 20 hours.

[0044] For the large yellow croaker samples in Examples 1 - 3 and Comparative Example 1, the total viable count (TVC), pH value, thiobarbituric acid value (TBARS), volatile basic nitrogen content (TVB - N) were measured every 2 days during storage. The changes in hardness, elasticity, and chewiness of the opened - back large yellow croaker were measured every 4 days during storage. The residual amount of ClO2 in the fish meat and the fish meat fiber structure were measured for different large yellow croaker samples on the 0th day and the 18th day.

[0045] 1. Determination of total viable count (TVC) Put 3 g of large yellow croaker fish meat sample into a sterile homogenization bag and add 27 mL of sterile 1% BPW buffer. Use a sterile homogenizer to beat the homogenization bag at a speed of 8.5 times per second for 5 minutes to obtain a bacterial suspension with a concentration of 10 -1 . Continuously dilute the bacterial suspension with a concentration of 10 -1 with sterile 1% BPW buffer. Pipette 1 mL of the bacterial suspension with a concentration of 10 -1 and place it in a test tube containing 9 mL of sterile 1% BPW buffer. After homogenization, a bacterial suspension with a concentration of 10 -2 is prepared. Pipette 1 mL of the bacterial suspension with a concentration of 10 -2 and place it in a test tube containing 9 mL of sterile 1% BPW buffer. After homogenization, a bacterial suspension with a concentration of 10 -3 is prepared, and so on. Use a pipette to respectively pipette 0.1 mL of the bacterial suspension of each concentration gradient onto TSA plate count agar, and use a sterile spreader to evenly spread the bacterial suspension. Incubate the spread TSA plates in a 30 °C biochemical incubator for 48 hours, and select the petri dishes with 25 - 250 colonies for counting and statistics.

[0046] As Figure 1 , compared with Comparative Example 1, the number of colonies of the sample treated with blue light - ClO2 combination (Example 1) decreased by 2.5 log CFU / g on the 18th day of storage. Compared with the single blue light treatment (Example 2) and the single ClO2 treatment (Example 3), the blue light - ClO2 combination treatment (Example 1) showed a better antibacterial effect, with the antibacterial effect increased by 0.5 log CFU / g, indicating that the combination of blue light and chlorine dioxide treatment can more effectively reduce the growth rate of microorganisms in large yellow croaker fish meat during storage. This may be because ClO2 can diffuse into the interior of the food and completely destroy the basic structure of bacteria, while the photocatalytic effect of blue light can promote the decomposition of ClO2 to generate strongly oxidizing free radicals, further enhancing the bactericidal effect. The combination of this dual mechanism not only makes up for the limitation of the insufficient penetration of the single blue light technology but also can synergistically attack microorganisms from multiple targets, producing a synergistic effect, thus enhancing the bactericidal effect.

[0047] 2. pH value determination Weigh 5 g of large yellow croaker fish meat, stir it evenly, put it into 45 mL of distilled water, oscillate for 5 minutes, filter out the fish connective tissue, and then measure it with a pH meter.

[0048] As Figure 2 , after the fish body dies, it will successively enter the rigor mortis stage and the autolysis stage. On the 2nd day of storage, the pH value of Comparative Example 1 dropped to 6.59 ± 0.07, while the pH value of the examples remained above 6.7. This phenomenon may be due to the fact that the ClO2 and blue light treatments inhibit the catabolism of glycogen and ATP by microorganisms, reducing the accumulation of acidic products. During the autolysis stage of the fish meat, the pH values of the samples in Examples 1-3 increased more slowly than those in the comparative example. The pH values of Comparative Example 1, Example 1, Example 2, and Example 3 on the 18th day of storage were 7.33, 7.23, 7.12, and 7.20, respectively. This is because the ClO2 and blue light treatments inhibit the activity of microbial proteases, reduce the generation of alkaline substances such as trimethylamine, and at the same time reduce the degree of autolysis of muscle tissue, resulting in a slower pH increase rate. Therefore, the ClO2 and blue light treatments can delay the rigor mortis and autolysis processes of the fish body and play a certain role in preserving the quality of the fish meat.

[0049] 3. Total volatile basic nitrogen (TVB-N) Determine according to the microdiffusion method in the second method of GB 5009.5—2016 "National Food Safety Standard Determination of Total Volatile Basic Nitrogen in Foods". It is required that the TVB-N content of freshwater fish and shrimp during storage should be ≤ 30 mg / 100 g.

[0050] As Figure 3 shown, the TVB-N value of Comparative Example 1 reached 39.9 mg / 100 g on the 18th day of storage, far exceeding the acceptable range (30 mg / 100 g) stipulated by Commission Regulation (EC) No. 1022 / 2008 of the European Commission, while the TVB-N values of Examples 1-3 on the 18th day were 26.6 mg / 100 g, 26.6 mg / 100 g, and 26.25 mg / 100 g, respectively, all of which did not exceed the acceptable range. Compared with the single blue light treatment (Example 2) and the single ClO2 treatment (Example 3), the blue light-ClO2 combined treatment (Example 1) showed a more excellent effect in inhibiting the increase of TVB-N value, and the overall trend of its TVB-N value increase was relatively slow. This may be because of the synergistic effect of blue light and ClO2, which realizes the dual regulation of microorganisms and endogenous enzymes, thus achieving a more comprehensive and efficient preservation effect.

[0051] 4. Determination of TBARS value Chop 5 g of large yellow croaker muscle, then mix it with 25 mL of 20% trichloroacetic acid and 20 mL of distilled water, centrifuge at 8000 rpm for 10 min, and dilute the filtrate to 50 mL with ultrapure water. Heat the mixture of 10 mL of the diluted solution and 10 mL of thiobarbituric acid solution in a boiling water bath at 95 - 100 °C for 15 minutes to form a pink color, and then cool it with running tap water for 5 minutes. Measure the absorbance of the cooled supernatant at 532 nm using a spectrophotometer. Calculate the TBARS value according to the following formula, where A is the absorbance value of the measured sample solution. TBARS (mg / 100 g) = A × 7.8

[0052] The TBARS value is an important reference index for evaluating the degree of lipid oxidation. The larger the TBARS value, the higher the degree of lipid oxidation. As Figure 4 shown, on the 18th day of storage, the TBARS values of Examples 1 - 3 are lower than that of Comparative Example 1, indicating that the application of ClO2 and blue light treatment can slow down the fat oxidation degree of large yellow croaker, effectively extend the storage time of large yellow croaker, and improve its fresh-keeping effect.

[0053] 5. Analysis of residual amount of chlorine dioxide (ClO2) Referring to the method of GB 5009.224 - 201, determine the residual amount of ClO2 in large yellow croaker fish meat under 2 ClO2 treatment groups (Example 1 and Example 3) on the 18th day of storage. Weigh 5.00 ± 0.10 g of minced fish meat sample and place it in a 50 mL centrifuge tube. Add 20 mL of phosphate buffer solution to the sample, oscillate and extract for 3 min and then filter. Extract the residue with 20 mL of the same buffer solution again, combine the two filtrates, and conduct a blank control experiment synchronously. Transfer the combined filtrate to a 50 mL centrifuge tube, centrifuge at 10000 r / min for 10 min at 4 °C, discard the upper layer of grease, dissolve the precipitate with phosphate buffer solution, and detect it by spectrophotometry. Take 50 mL of the filtrate and place it in a 50 mL stoppered colorimetric tube, add 1.0 mL of malonic acid solution and mix, add 1.5 mL of phosphate buffer solution and 1.0 mL of DPD color reagent and mix evenly. Immediately, within 2 minutes, measure the absorbance at 552 nm using a 1 cm colorimetric cell, and calculate the concentration of ClO2 according to the standard curve. Calculate the residual amount of ClO2 in the sample according to the following formula: X is the residual amount of ClO2 in the sample, with the unit of mg / kg; C is the concentration of ClO2 in the sample solution, with the unit of mg / L; C0 is the concentration of ClO2 in the reagent blank, with the unit of mg / L; V is the final volume of the sample solution for volume fixation, with the unit of mL; m is the mass of the sample represented by the final sample solution, with the unit of g; 1.9 is the conversion coefficient between ClO2 and available chlorine.

[0054] As shown in Table 1, the residual amount of ClO2 in the large yellow croaker fish treated with ClO2 alone (Example 3) was 4.76 ± 0.11 mg / kg; the residual amount of ClO2 in the large yellow croaker fish treated with blue light-ClO2 combination (Example 1) was 1.88 ± 0.06 mg / kg, both of which did not exceed the detection limit (5 mg / kg) specified in GB 5009.224-2016 and were within the safe range. At the same time, the ClO2 residual amount in Example 1 was significantly lower than that in Example 3. This indicates that after the treatment with ClO2 alone, ClO2 could not be fully decomposed or volatilized and thus remained in the fish meat. While the blue light-ClO2 combination treatment can effectively play a bactericidal role, it can also partially degrade the residual ClO2 in the fish meat. This not only reflects the advantage of the blue light combined with ClO2 treatment in controlling the residual amount but also meets the requirement of low residue of chemical agents for food safety.

[0055] Table 1 Residual amount of ClO2 in large yellow croaker fish meat (Note: "±" is the standard error of three parallels, and different letters in the data of different treatment groups represent significant differences (P < 0.05)) 6. Texture After deboning the back muscle of the fish, take 2 cm × 2 cm × 2 cm fish meat with fish skin and analyze it using a full-touch texture analyzer. Conditions of the full-touch texture analyzer: the diameter of the disc-shaped probe is 25 mm; the pre-test speed is 2 mm / s; the post-test speed is 5 mm / s; the in-test speed is 60 mm / min; the measurement interval time is 5 s; the compression ratio is 30%; the minimum test force is 0.15 N; the time interval between two compressions is 5 s; the range of the force sensor element is 100 g.

[0056] The texture characteristics of large yellow croaker are closely related to its freshness. As Figure 5 、 Figure 6 、 Figure 7 shown, the hardness ( Figure 5 ), elasticity ( Figure 6 ), chewiness ( Figure 7)Both showed a trend of first increasing and then decreasing. The reason may be that after farmed large yellow croaker dies, it first enters the rigor mortis stage. In the later stage of storage, due to the degradation of endogenous proteases and spoilage microorganisms, the protein molecular structure changes, and it enters the autolysis stage, resulting in a decrease in the hardness, elasticity, and chewiness indices. Compared with Examples 1-3, in Comparative Example 1, due to the relatively rapid growth of microorganisms, the protein structure of the fish meat was severely damaged, and the texture characteristics decreased the fastest. Compared with the single blue light treatment (Example 2) and the single ClO2 treatment (Example 3), the blue light-ClO2 combined treatment (Example 1) effectively maintained the elasticity and chewiness of the large yellow croaker fish meat while increasing the hardness of the large yellow croaker, and better maintained the texture characteristics. This is because compared with the single blue light / ClO2 treatment technology, the blue light-ClO2 combined treatment more effectively inhibits microbial reproduction, endogenous enzyme activity, and cell metabolism through synergistic effects, thereby delaying protein hydrolysis and better maintaining the hardness, elasticity, and chewiness of the fish meat.

[0057] 7. Microscopic Structure Analysis of Fish Muscle Fibers Fish samples (10 mm × 10 mm × 10 mm) cut perpendicular to the muscle fibers were fixed with 4% paraformaldehyde for 24 h. Then, at 4 °C, an automatic ethanol dehydrator (Beino, China) was used to dehydrate the samples with ethanol solutions of gradient concentrations (70%-100%, v / v). Then the tissue was immersed in xylene to keep it transparent. The samples were soaked in paraffin to ensure the fixation of the fish tissue. Then the samples were embedded in paraffin in an embedding station (Beino, China) for easy sectioning. Sections were obtained using a microtome and were stained with hematoxylin and eosin, and then observed under an optical microscope (E100, Nikon, Japan) at a magnification of 100×.

[0058] As Figure 8As shown in the figure. On the 0th day, there was no significant difference in the fish muscle tissues between the examples and the control group, and the distribution of muscle fibers was uniform and the shape was regular. After 18 days of storage, in the fish muscle tissue of the control group 1, there were phenomena such as large pores in the muscle fiber bundles, blurred muscle bundles, and incomplete muscle tissues. The reason for the degradation of muscle fibers may be the action of spoilage bacteria and endogenous enzymes. In the fish muscle tissues treated with single blue light / ClO2 (Examples 2 and 3), there were partial fractures, but the formed gaps were finer compared to the control group, which reduced the damage to the continuity of the muscle tissue to a certain extent. In the fish muscle tissue treated with blue light-ClO2 combination (Example 1), although there were tearing phenomena, from the overall structure, it maintained a higher muscle tissue integrity compared to the single technology treatment, and maintained the original structural form of the fish muscle to the greatest extent. This may be due to the strong inhibitory effect of the blue light combined with ClO2 treatment on the growth of spoilage microorganisms. By inhibiting the reproduction of microorganisms, it reduced the erosion of muscle tissues by microbial metabolites. At the same time, this treatment method also effectively regulated the activity of endogenous enzymes in large yellow croaker, reduced the decomposition of muscle proteins by endogenous enzymes, and thus significantly delayed the degradation process of muscle tissues.

[0059] 8. SEM analysis of fish muscle fibers The fish muscle samples were cut into cubes with dimensions of 5 mm×5 mm×2 mm along the muscle fiber direction, fixed with 2.5% glutaraldehyde for 24 h, then rinsed with phosphate buffer for 0.5 h, and then dehydrated with a gradient series of ethanol solutions (50% - 100%, v / v). The samples were placed in a fume hood to remove ethanol, and then vacuum freeze-dried for 20 h. The dried samples were mounted on bronze stubs and coated with gold sputtering. Subsequently, the longitudinal sections of the muscle fibers of the samples were observed with a scanning electron microscope at a magnification of 100 times and an acceleration voltage of 5 kV.

[0060] As Figure 9 shown, at the initial stage of storage, there were no significant differences in the large yellow croaker samples of each group, and all showed typical fresh muscle characteristics such as dense and complete muscle fiber structures, smooth surfaces, and neat sarcomere arrangements. After 18 days of storage, in the fish muscle tissue of the control group 1, there were serious muscle bundle injuries, rough muscle fiber surfaces, and enlarged pores between muscle fiber bundles. This may be due to the action of endogenous enzymes and spoilage bacteria, resulting in the degradation of the fish muscle tissue. The fish muscle tissue treated with single blue light (Example 2) was smoother than the control group, but there were injuries on the muscle fiber surfaces. The fish muscle tissue treated with single ClO2 (Example 3) was more complete than the control group, but the surface muscle fibers were no longer smooth. Compared with the single treatment technology, the muscle fibers treated with blue light-ClO2 combination (Example 1) showed a smoother and more complete state, and the pores between muscle fibers were smaller. This may be because the combined treatment more effectively reduced the activity of endogenous enzymes in the fish muscle, inhibited the degradation of the fish muscle by spoilage bacteria, and maintained the fish muscle fiber structure better.

[0061] The above are only the preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. Application of combined treatment of blue light and chlorine dioxide in the preservation of large yellow croaker.

2. A preservation method for large yellow croaker using combined treatment of blue light and chlorine dioxide, characterized in that, It includes the following steps: (1) Prepare a chlorine dioxide-containing solution with pure water, freeze it into ice cubes and then crush them to obtain chlorine dioxide crushed ice; (2) Put the gutted large yellow croaker into a foam box filled with chlorine dioxide crushed ice, so that the fish body surface is completely covered by the chlorine dioxide crushed ice; (3) Transfer the foam box to a refrigerator at 0-4°C equipped with LED blue light for storage, and irradiate the gutted large yellow croaker in the foam box with LED blue light; during storage, regularly replace the chlorine dioxide crushed ice covering the fish body surface.

3. The method for preserving large yellow croaker according to claim 1, characterized in that: In step (1), the chlorine dioxide content in the chlorine dioxide crushed ice is 10 mg / L, and the size of the chlorine dioxide crushed ice is 0.80 ± 0.20 cm 3 .

4. The preservation method of large yellow croaker according to claim 1, wherein: In step (2), the fish body surface is completely covered by a chlorine dioxide crushed ice layer with a thickness of 3-4 cm.

5. The method according to claim 1, characterized in that: In step (3), the wavelength of the LED blue light is 405 nm.

6. The method according to claim 1, characterized in that: In step (3), the distance between the light source and the fish body is 20 cm.

7. The method according to claim 1, characterized in that: In step (3), the regular replacement is carried out once every 20 hours.

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