Bacteria-reducing and quality-guaranteeing method for lightly salted fish
Through the combined treatment method of microwave combined with slightly acidic electrolytic water, the problem of lightly pickled yellow croaker in processing and storage is solved, and efficient sterilization and quality-stopping effects are achieved, fat oxidation is reduced, and food safety and market competitiveness are improved. .
Patent Information
- Application Number
- CN202411349911.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-01-03
AI Technical Summary
Lightly pickled yellow croaker is prone to decay during processing and storage. The existing microwave sterilization methods are unevenly distributed in temperature, resulting in incomplete sterilization, and simple microwave treatment cannot effectively sterilize and maintain quality.
Using a combination of microwave combined with slightly acidic electrolytic water, vacuum packaging is carried out after microwave bacteria reduction and slightly acidic electrolytic water treatment, and placed in a refrigerated environment, combining microwave power, frequency, temperature, pH and effective chlorine of slightly acidic electrolytic water. The concentration and redox potential are optimized.
It significantly reduces the total colony count, maximizes the quality and flavor of lightly cured fish, slows down fat oxidation, improves food safety and market competitiveness, and avoids the safety hazards of chemical cleaning agent residues.
Smart Images
Figure CN119234868A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of aquatic product sterilization and quality preservation, and relates to a method for sterilization and quality preservation of lightly pickled fish, and specifically to a method for sterilization and quality preservation by combining microwave with slightly acidic electrolyzed water. Background Art
[0002] Large yellow croaker (Larimichthys crocea), commonly known as yellow croaker, is rich in nutrition and delicious. It is one of the traditional "four major seafoods" in China and is known as the "national fish". Large yellow croaker processed products mainly include salted large yellow croaker, smoked large yellow croaker and fragrant rice wine large yellow croaker. Among them, lightly pickled large yellow croaker is a salted processed product with the characteristics of low salt (≤6%) and high moisture (40% to 60%), which is deeply loved by consumers. However, microorganisms are very easy to multiply in large numbers during the processing and circulation of lightly pickled large yellow croaker, causing it to spoil during subsequent storage and processing. Therefore, only by using appropriate treatment methods to reduce the bacteria of lightly pickled large yellow croaker can the quality of lightly pickled large yellow croaker be maintained to the maximum extent while ensuring the safety of microorganisms.
[0003] Microwaves (MW) are non-ionizing electromagnetic waves with a frequency between 300 MHz and 300 GHz. They have the ability to destroy microorganisms through magnetic field coupling, electroporation, cell membrane rupture and selective heating, and can therefore be used to sterilize food. However, the uneven actual temperature distribution during microwave sterilization may lead to incomplete sterilization. In addition, due to the high mass transfer efficiency of microwaves, lipids precipitate, and the large amount of polyunsaturated fatty acids contained in fish are more easily oxidized. Therefore, microwaves alone cannot achieve effective sterilization and preservation of lightly pickled large yellow croaker. It is necessary to combine it with other technologies to ensure the safety of the product and maintain its good quality.
[0004] Slightly acidic electrolyzed water (SAEW) is an aqueous solution obtained by electrolyzing a dilute sodium chloride solution under a low-voltage direct current electric field. Its available chlorine concentration (ACC) is 10-30 mg / L, pH=5.0-6.5, and oxidation reduction potential (ORP)>850 mV. It has the characteristics of no residue, no pollution, safety and high efficiency, and is widely used in the field of pre-processing and preservation of aquatic products.
[0005] Therefore, the MW-SAEW combined treatment can improve the sterilization efficiency while having little impact on the quality of lightly pickled large yellow croaker. It can also slow down fat oxidation, extend the shelf life of the product, and enhance market competitiveness. Summary of the invention
[0006] In view of the technical problem that lightly pickled fish including lightly pickled large yellow croaker are easily spoiled during subsequent storage and processing, the present invention aims to provide a method for reducing bacteria and preserving the quality of lightly pickled fish by microwave combined with slightly acidic electrolyzed water, which is simple to operate, low in production cost and green and efficient.
[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:
[0008] The method for preserving lightly pickled fish by microwave combined with slightly acidic electrolyzed water comprises the following steps: subjecting the lightly pickled fish with a central temperature of -2 to 0°C to microwave sterilization treatment and slightly acidic electrolyzed water sterilization treatment, and then vacuum packaging the treated lightly pickled fish, and storing the packaged lightly pickled fish in a cold storage at 0 to 4°C.
[0009] Preferably, the lightly pickled fish is a fish having a salt content of ≤6% and a moisture content of 40-60% after pickling; the lightly pickled fish is selected from lightly pickled large yellow croaker, lightly pickled pomfret, lightly pickled sea bass, lightly pickled whitefish, lightly pickled herring, etc.
[0010] Preferably, in order to preserve the quality, large yellow croaker or pomfret are usually placed in a freezing environment of -18°C after being pickled, so before the sterilization treatment, the lightly pickled fish stored at -18°C is first thawed at 0-4°C to a core temperature of -2-0°C.
[0011] Preferably, after the combined sterilization treatment, microwave sterilization treatment is performed first, and then slightly acidic electrolyzed water sterilization is performed to improve the ease of operation.
[0012] Further preferably, the microwave sterilization treatment conditions are as follows: microwave power: 425-850W, frequency: 2440-2460Hz, temperature: 30-40°C, treatment time: 10-25min. The most preferred treatment conditions are as follows: microwave power: 850W, frequency: 2450Hz, temperature: 35°C, treatment time: 10-20min.
[0013] Further preferably, the conditions for the treatment of slightly acidic electrolyzed water for sterilization are as follows: pH: 6.0-6.5, effective chlorine concentration: 35-55ppm, redox potential: 850-950mv, treatment time: 10-20min. The most preferred treatment conditions are as follows: pH: 6.2, effective chlorine concentration: 45ppm, redox potential: 900mV, treatment time: 10min.
[0014] Further preferably, the method of sterilization treatment with slightly acidic electrolyzed water is selected from immersion or spraying, preferably immersion treatment.
[0015] Compared with the prior art, the remarkable effects are:
[0016] The method for preserving lightly pickled fish by micro-reduction of bacteria provided by the present invention combines acidic electrolyzed water treatment, microwave treatment and vacuum packaging, which reduces the total colony count by 3 orders of magnitude while retaining the quality and flavor of the lightly pickled fish to the maximum extent, reduces the degree of fat oxidation, and increases the safety of subsequent processing and circulation.
[0017] The present invention has the characteristics of simple operation, green and healthy, etc., focuses on the antibacterial properties of acidic electrolyzed water treatment combined with microwaves, purifies pathogenic bacteria and spoilage bacteria more thoroughly, and avoids the safety hazards of residual traditional chemical cleaning agents. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It shows the changes in the number of microorganisms in lightly pickled large yellow croaker under different sterilization treatment conditions;
[0019] Figure 2 The effect of acidic electrolyzed water combined with microwave treatment on fish meat firmness is shown;
[0020] Figure 3 The effects of acidic electrolyzed water combined with microwave treatment on the elasticity of fish meat are shown;
[0021] Figure 4 The effect of acidic electrolyzed water combined with microwave treatment on the degree of fat oxidation (TBA value) is shown. DETAILED DESCRIPTION
[0022] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.
[0023] Taking lightly pickled large yellow croaker as an example, the effects of the sterilization operation under different conditions are compared. The protection scope of the present invention is not limited to the sterilization treatment of lightly pickled large yellow croaker, but is also applicable to other lightly pickled fish species that require sterilization treatment.
[0024] 1. Treatment of lightly pickled yellow croaker under different sterilization conditions
[0025] Example 1
[0026] Select 2500g lightly pickled large yellow croaker (fish weight 250-275g / fish) and thaw at 0-4℃ until the center temperature is -2-0℃. The thawed lightly pickled large yellow croaker is microwaved for 10min, with a microwave power of 850W, a frequency of 2450Hz, and a temperature of 35℃. Then soak it in 15L of slightly acidic electrolyzed water for 10min, and its physicochemical parameters are: pH: 6.2, effective chlorine concentration: 45ppm, and redox potential: 900mV. Put the lightly pickled large yellow croaker after sterilization into a high-temperature cooking bag and vacuum pack it. Finally, store the packaged lightly pickled large yellow croaker in a refrigerator at 0-4℃.
[0027] Example 2
[0028] Select 2500g lightly pickled large yellow croaker (fish weight 250-275g / fish) and thaw at 0-4℃ until the center temperature is -2-0℃. The thawed lightly pickled large yellow croaker is microwaved for 20min, with a microwave power of 850W, a frequency of 2450Hz, and a temperature of 35℃. Then soak it in 15L of slightly acidic electrolyzed water for 10min, and its physicochemical parameters are: pH: 6.2, effective chlorine concentration: 45ppm, and redox potential: 900mV. Put the lightly pickled large yellow croaker after sterilization into a high-temperature cooking bag and vacuum pack it. Finally, store the packaged lightly pickled large yellow croaker in a refrigerator at 0-4℃.
[0029] Comparative Example 1
[0030] 2500g lightly salted large yellow croaker (fish weight 250-275g / fish) was selected and thawed at 0-4°C until the core temperature was -2-0°C. The thawed lightly salted large yellow croaker was directly placed in a high-temperature cooking bag without sterilization treatment and vacuum packed. Finally, the packaged lightly salted large yellow croaker was stored in a refrigerated place at 0-4°C.
[0031] Comparative Example 2
[0032] 2500g lightly salted large yellow croaker (fish weight 250-275g / fish) was selected and thawed at 0-4℃ until the core temperature was -2-0℃. The thawed lightly salted large yellow croaker was soaked in 15L of acidic electrolyzed water for 20min, and its physicochemical parameters were: pH: 6.2, effective chlorine concentration: 45ppm, redox potential: 900mV. The lightly salted large yellow croaker after sterilization was placed in a high-temperature cooking bag and vacuum packed. Finally, the packaged lightly salted large yellow croaker was stored in a refrigerator at 0-4℃.
[0033] Comparative Example 3
[0034] 2500g lightly pickled yellow croaker (fish weight 250-275g / fish) was selected and thawed at 0-4°C to a core temperature of -2-0°C. The thawed lightly pickled yellow croaker was subjected to microwave treatment for only 20 minutes, with a microwave treatment power of 850W, a frequency of 2450Hz, and a temperature of 35°C. The lightly pickled yellow croaker after sterilization was placed in a high-temperature cooking bag and vacuum packed. Finally, the packaged lightly pickled yellow croaker was stored in a refrigerated container at 0-4°C.
[0035] Comparative Example 4
[0036] Select 2500g lightly pickled large yellow croaker (fish weight 250-275g / fish) and thaw at 0-4℃ until the center temperature is -2-0℃. The thawed lightly pickled large yellow croaker is microwaved for 25min, with a microwave power of 850W, a frequency of 2450Hz, and a temperature of 35℃. Then soak it in 15L of slightly acidic electrolyzed water for 10min, and its physicochemical parameters are: pH: 6.2, effective chlorine concentration: 45ppm, and redox potential: 900mV. Put the lightly pickled large yellow croaker after sterilization into a high-temperature cooking bag and vacuum pack it. Finally, store the packaged lightly pickled large yellow croaker in a refrigerated storage at 0-4℃.
[0037] 2. Related indicators detection
[0038] 1. Microbiological determination: The dilution of all samples was carried out according to the method in GB 4789.2-2022 "National Food Safety Standard for Microbiological Examination of Food Colony Count Determination". The inoculation method was the pouring method, and the total colony count medium was plate count agar medium; crystal violet neutral red bile salt glucose agar was used for Enterobacteriaceae culture; iron agar medium was used for H2S-producing bacteria culture, and two parallels were made for each dilution gradient. Enterobacteriaceae were cultured in a 37°C constant temperature incubator for (24±1)h, and the remaining samples were cultured in a 28°C constant temperature incubator. After (48±1)h, the colonies were counted respectively, and the colonies of H2S-producing bacteria in iron agar medium were black.
[0039] 2. Texture measurement: Take the back muscle of large yellow croaker (2cm×2cm×1cm) and carry out texture measurement, including hardness, elasticity, adhesion, chewiness, stickiness and cohesion. Use P / 5 cylindrical probe, test speed 50mm / min, deformation 50%, recovery height 30mm, and each group of samples is measured 6 times independently.
[0040] 3. TBA value determination: The TBA value is expressed as the malondialdehyde content (mg / kg) in the sample. Weigh 5.0g of homogenized fish meat and place it in a 100mL stoppered conical flask, add 50mL of 7.5% TCA solution, seal it with a stopper, shake it on an oscillator for 30 minutes, filter it with double-layer filter paper, and collect the filtrate. Take 1ml of the obtained filtrate and add an equal amount of TBA (0.02mol / L), react in a boiling water bath for 30 minutes, take it out and cool it to room temperature, take an appropriate amount of supernatant solution and measure the absorbance at a wavelength of 532nm. Use 1,1,3,3-tetraethoxypropane as a standard curve and repeat the measurement three times.
[0041] 4. Results Analysis
[0042] Changes in the number of microorganisms in lightly pickled large yellow croaker under different sterilization treatment conditions Figure 1As shown, compared with the untreated group (Comparative Example 1), the simple acidic electrolyzed water immersion treatment group (Comparative Example 2) has a slight bacteria reduction effect, but not as good as the simple microwave treatment group (Comparative Example 3), which has a good bacteria reduction effect, and the slightly acidic electrolyzed water combined with microwave treatment group (Examples 1 and 2) has a significantly improved bacteria reduction effect. The microwave treatment was extended from 10min to 25min, and the total number of colonies and hydrogen sulfide-producing bacteria did not change significantly.
[0043] Figure 2 and Figure 3 The effect of acidic electrolyzed water combined with microwave treatment on hardness and elasticity. The hardness and elasticity of the group treated with microwave for 10 to 20 minutes (Example 1 and Example 2) are significantly higher than those of the group treated with microwave for 25 minutes (Comparative Example 4).
[0044] Figure 4 The effect of acidic electrolyzed water combined with microwave treatment on the degree of fat oxidation (TBA value). Compared with the untreated group (Comparative Example 1), the TBA values of the single treatment groups (Comparative Example 2 and Comparative Example 3) and the slightly acidic electrolyzed water combined with microwave treatment for 10 to 20 minutes (Example 1 and Example 2) were significantly reduced, while the slightly acidic electrolyzed water combined with microwave treatment for 25 minutes (Comparative Example 4) was significantly increased.
[0045] In summary, the products of Examples 1 and 2 of the present invention have good sterilization effects, have little impact on quality, and can reduce the degree of fat oxidation.
[0046] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.
Claims
1. A method for reducing bacteria and preserving quality of lightly pickled fish, characterized in that: The following steps are involved: The lightly pickled fish with a core temperature of -2 to 0°C is subjected to microwave sterilization treatment and slightly acidic electrolyzed water sterilization treatment, and then vacuum-packed, and the packaged lightly pickled fish is stored in a refrigerated storage at 0 to 4°C. The microwave sterilization treatment conditions are as follows: microwave power: 425-850W, frequency: 2440-2460Hz, temperature: 30-40℃, treatment time: 10-25min; The conditions for the bacteria reduction treatment of slightly acidic electrolyzed water are as follows: pH: 6.0-6.5, effective chlorine concentration: 35-55ppm, redox potential: 850-950mv, and treatment time: 10-20min.
2. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, The lightly salted fish is a fish with a salt content of ≤6% and a water content of 40-60% after being salted.
3. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, The lightly cured fish is selected from any one of lightly cured large yellow croaker, lightly cured pomfret, lightly cured sea bass, lightly cured white fish and lightly cured herring.
4. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, The lightly pickled fish is stored in a freezing environment at -18°C. Before the sterilization treatment, the lightly pickled fish is first thawed at 0-4°C to a core temperature of -2-0°C.
5. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, When performing the sterilization treatment, microwave sterilization treatment is first performed, and then slightly acidic electrolyzed water sterilization treatment is performed.
6. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, The microwave sterilization treatment conditions are as follows: microwave power: 850W, frequency: 2450Hz, temperature: 35℃, treatment time: 10-20min.
7. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, The conditions for the bacterial reduction treatment of slightly acidic electrolyzed water are as follows: pH: 6.2, effective chlorine concentration: 45ppm, redox potential: 900mV, and treatment time: 10min.
8. The method for reducing bacteria and preserving quality of lightly salted fish according to claim 1, characterized in that: in, When vacuum packaging is performed, high-temperature cooking bags are used for packaging.