Method for prolonging shelf life of chilled chicken

Abstract

The invention relates to the technical field of food preservation, in particular to a method for prolonging the shelf life of chilled fresh chicken, and the method for prolonging the shelf life of chilled fresh chicken comprises the following steps: 1) preparing a plasma activation solution; (2) soaking the chilled fresh chicken by using the plasma activation solution in the step (1); and (3) draining the iced fresh chicken in the step (2), and packaging and storing the iced fresh chicken. According to the method, the chilled chicken is soaked in the plasma activation solution, during the storage period, growth and reproduction of microorganisms on the surface of the chilled chicken are remarkably inhibited, the lipid oxidation phenomenon is relieved, the storage quality of the chilled chicken is maintained, the shelf life is prolonged, a new thought is provided for fresh keeping of the chilled chicken, and the method has wide application prospects. Meanwhile, the method is simple, convenient, low in cost, green, environment-friendly and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of food preservation, and in particular to a method for extending the shelf life of chilled chicken. Background Art

[0002] In my country, chicken is the second most consumed meat after pork. In 2024, broiler chicken consumption reached 14.83 million tons, accounting for 14.72% of global consumption; total chicken production reached 15 million tons, accounting for 14.5% of global chicken production.

[0003] Chilled chicken refers to chicken carcasses that have been slaughtered and then chilled in ice water and air-chilled to a temperature of 0-4°C within an hour. The carcass temperature is then maintained within this temperature range during processing, distribution, and retail. Compared to hot-fresh and frozen chicken, chilled chicken, with its tenderness and high nutritional value, has become an essential choice for consumers, and its share of national meat consumption is gradually increasing. Due to the impact of avian influenza, the market share of chilled chicken has been growing. However, chilled broiler chicken products generally suffer from a significant quality decline during post-refrigeration storage. Due to the high protein content and water activity of chilled chicken, it is a natural breeding ground for microbial growth and reproduction. During production, processing, and distribution, it is highly susceptible to microbial contamination, leading to spoilage, shortening its shelf life and posing a health hazard. Research shows that the shelf life of chilled chicken stored at 0-4°C is only about three days. Beyond this expiration date, the chicken may become sour, sticky, develop bacterial plaque, deteriorate in appearance, and develop an off-flavor.

[0004] Currently, there are a variety of antibacterial and preservation methods for chilled chicken, but many shortcomings remain. Sodium hypochlorite is a powerful, efficient, broad-spectrum, and easy-to-use bacteriostatic agent. In my country, sodium hypochlorite is commonly used in the pre-chilling and sterilization process of broiler chickens. However, sodium hypochlorite may react with organic matter to form carcinogens, causing public health problems in the food industry. Therefore, the European Union prohibits the use of sodium hypochlorite in direct contact with food. If livestock products are to be exported to the EU and Islamic countries, chlorine-free chemical bacteriostatic agents must be used. Therefore, the food industry is in great need of new antibacterial agents such as plasma activated water (PAW), which can reduce the contamination of spoilage microorganisms in food while maintaining the nutritional quality of the product.

[0005] Plasma-activated water (PAW) is typically produced by performing atmospheric pressure cold plasma discharge in distilled water or on the surface of water using a plasma device. When plasma comes into contact with water, the interfacial reaction between the plasma and water can produce a series of primary and secondary active products, thereby forming reactive oxygen species and reactive nitrogen species in the plasma-activated water. Furthermore, the interaction between water and plasma also affects the physicochemical properties of PAW. After low-temperature plasma treatment, the pH value of the aqueous solution decreases, the conductivity increases, the intensity of the ultraviolet absorption peak increases, the nitrite content increases, and the redox potential (ORP) increases. However, plasma-activated water is currently rarely used in the preservation of chilled chicken, and the adjustable intensity range is not suitable. There are no reports on its application in the preservation and anti-corrosion of chilled broiler products. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems of the short shelf life of existing chilled chicken and the EU's ban on direct contact of sodium hypochlorite with food, thereby providing a method for extending the shelf life of chilled chicken. The method uses a plasma-activated solution to soak the chilled chicken. During storage, the growth and reproduction of microorganisms on the surface of the chilled chicken is significantly inhibited, lipid oxidation is slowed down, and the storage quality of the chilled chicken is maintained. The method provides a new idea for preserving chilled chicken and has broad application prospects. At the same time, the method is simple, convenient, low-cost, environmentally friendly, and suitable for industrial production.

[0007] In order to achieve the above object, the present invention provides a method for extending the shelf life of chilled chicken, the method comprising:

[0008] 1) preparing a plasma activation solution;

[0009] 2) soaking the chilled chicken in the plasma activation solution described in step 1);

[0010] 3) Draining the chilled chicken in step 2) and packaging for storage.

[0011] Preferably, in step 1), the plasma activated solution is obtained by treating a plasma activated solution preparation solution with a plasma activated solution preparation device for 15-30 minutes.

[0012] Preferably, the plasma activated solution preparation equipment comprises:

[0013] A reaction chamber, which is a hollow cavity closed at both ends and used for reacting the plasma activation solution preparation liquid with the plasma;

[0014] A solution inlet is provided at the upper left of the reaction chamber and is connected to the reaction chamber through a pipeline for inputting a plasma activation solution preparation solution;

[0015] Two plasma jet devices, which are arranged in parallel above the reaction chamber and connected to the reaction chamber through a pipeline, and are used to generate and process plasma;

[0016] A solution outlet is provided directly below the reaction chamber and connected to the reaction chamber via a pipeline for outputting the treated plasma-activated solution;

[0017] A switch is provided outside the reaction chamber and is used to operate and control the entire device.

[0018] Preferably, the plasma activation solution preparation solution consists of water and / or citric acid solution.

[0019] Preferably, the concentration of the citric acid solution is 0.05-1.0 wt %.

[0020] Preferably, the operating conditions of the plasma activated solution preparation equipment include: using air as the working carrier, a flow rate of 30-40 L / min, an equipment operating voltage of 220 V, a frequency of 50 Hz, and a discharge distance of 6 mm.

[0021] Preferably, in step 2), the material-liquid ratio of the plasma activated solution to the chilled chicken is 1:1.5-2.

[0022] Preferably, in step 2), the soaking treatment time is 10-20 minutes.

[0023] Preferably, in step 3), the packaging and storage conditions include: sealing the drained chilled chicken in a sterile bag and storing it at a temperature of 0-4°C.

[0024] In the above technical scheme, the method for extending the shelf life of chilled chicken of the present invention comprises the following steps: plasma-treating a plasma-activated solution preparation liquid by a plasma-activated solution preparation device to obtain a plasma-activated solution, wherein reactive oxygen species and reactive nitrogen species are formed in the plasma-activated solution. The plasma-activated solution is used to soak the chilled chicken, which can significantly inhibit the growth and reproduction of microorganisms on the surface of the chilled chicken, slow down lipid oxidation, and is beneficial to maintaining the storage quality of the chilled chicken and extending the shelf life of the chilled chicken.

[0025] At the same time, the method for extending the shelf life of chilled chicken of the present invention has simple steps, low cost and is green and environmentally friendly, provides a new idea for preserving chilled chicken, and has broad application prospects.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 Schematic diagram and actual picture of the plasma activated solution preparation equipment of Preparation Example 1 of the present invention;

[0029] Figure 2 This is the change in the total bacterial count on the surface of chilled chicken during storage in detection example 1 of the present invention;

[0030] Figure 3 This is the change of coliform bacteria on the surface of chilled chicken during storage in detection example 1 of the present invention;

[0031] Figure 4 This is the change of lipid peroxidation products (TBARS) of chilled chicken during storage in detection example 2 of the present invention;

[0032] Figure 5 This is the change in nitrite content on the surface of chilled chicken during storage in detection example 3 of the present invention. DETAILED DESCRIPTION

[0033] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0034] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0035] The present invention provides a method for extending the shelf life of chilled chicken, the method comprising:

[0036] 1) preparing a plasma activation solution;

[0037] 2) soaking the chilled chicken in the plasma activation solution described in step 1);

[0038] 3) Draining the chilled chicken in step 2) and packaging for storage.

[0039] The present invention discloses a method for extending the shelf life of chilled chicken. The method comprises the following steps: plasma-treating a plasma-activated solution preparation solution using plasma-activated solution preparation equipment to obtain a plasma-activated solution. Active oxygen species and active nitrogen species are formed in the plasma-activated solution. The plasma-activated solution is used to soak the chilled chicken, thereby significantly inhibiting the growth and reproduction of microorganisms on the surface of the chilled chicken and slowing down lipid oxidation, thereby facilitating the maintenance of the storage quality of the chilled chicken and extending the shelf life of the chilled chicken.

[0040] At the same time, the method for extending the shelf life of chilled chicken of the present invention has simple steps, low cost and is green and environmentally friendly, provides a new idea for preserving chilled chicken, and has broad application prospects.

[0041] In a preferred embodiment of the present invention, in step 1), the plasma activated solution is obtained by treating a plasma activated solution preparation solution with a plasma activated solution preparation device for 15-30 minutes.

[0042] In a preferred embodiment of the present invention, the plasma activated solution preparation equipment comprises:

[0043] A reaction chamber, which is a hollow cavity closed at both ends and used for reacting the plasma activation solution preparation liquid with the plasma;

[0044] A solution inlet is provided at the upper left of the reaction chamber and is connected to the reaction chamber through a pipeline for inputting a plasma activation solution preparation solution;

[0045] Two plasma jet devices, which are arranged in parallel above the reaction chamber and connected to the reaction chamber through a pipeline, and are used to generate and process plasma;

[0046] A solution outlet is provided directly below the reaction chamber and connected to the reaction chamber via a pipeline for outputting the treated plasma-activated solution;

[0047] A switch is provided outside the reaction chamber and is used to operate and control the entire device.

[0048] In a preferred embodiment of the present invention, the plasma activation solution preparation solution consists of water and / or citric acid solution.

[0049] In a preferred embodiment of the present invention, the concentration of the citric acid solution is 0.05-1.0 wt%, for example, it can be 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.8 wt% or 1.0 wt%.

[0050] In a preferred embodiment of the present invention, the operating conditions of the plasma activated solution preparation equipment include: using air as the working carrier, a flow rate of 30-40 L / min, an equipment operating voltage of 220 V, a frequency of 50 Hz, and a discharge distance of 6 mm.

[0051] In a preferred embodiment of the present invention, in step 2), the material-liquid ratio of the plasma activated solution to the chilled chicken is 1:1.5-2.

[0052] In a preferred embodiment of the present invention, in step 2), the soaking treatment time is 10-20 minutes.

[0053] In a preferred embodiment of the present invention, in step 3), the packaging and storage conditions include: sealing the drained chilled chicken in a sterile bag and storing it at a temperature of 0-4°C.

[0054] The present invention will be described in detail below by way of examples. In the following examples, the drugs and pharmaceuticals are all conventional commercial products.

[0055] Preparation Example 1

[0056] Preparation of plasma activation solution:

[0057] Prepare 3 L of pure water and treat the pure water with a plasma activated solution preparation device for 20 minutes to prepare a plasma activated solution;

[0058] Among them, the operating conditions of the plasma activated solution preparation equipment are: air as the working carrier, a flow rate of 35L / min, an operating voltage of 220V, a frequency of 50Hz, and a discharge distance of 6mm.

[0059] Preparation Example 2

[0060] Prepare 3 L of a 0.2 wt% citric acid solution, and treat the solution for 20 minutes using a plasma activated solution preparation device to prepare a plasma activated solution.

[0061] Among them, the operating conditions of the plasma activated solution preparation equipment are: air as the working carrier, a flow rate of 35L / min, an operating voltage of 220V, a frequency of 50Hz, and a discharge distance of 6mm.

[0062] Example 1

[0063] S1. After the plasma activated solution in Example 1 is cooled to room temperature (15-35° C.), the chilled chicken is immersed in the plasma activated solution at a material-to-liquid ratio of 1:1.5 for 15 minutes.

[0064] S2. Drain the surface moisture of the chilled chicken processed in S1 in a laminar flow hood, seal it in a sterile bag, and refrigerate it at 4°C. This is recorded as PAW.

[0065] Example 2

[0066] The method described in Example 1 was followed, except that the plasma activated solution in Preparation Example 1 in step S1 was replaced with an equal amount of the plasma activated solution in Preparation Example 2, which was denoted as PACA.

[0067] Comparative Example 1

[0068] The method described in Example 1 was followed, except that the plasma activation solution in Preparation Example 1 in step S1 was replaced with an equal amount of 50 ppm sodium hypochlorite solution, denoted as NaClO.

[0069] Test Example 1

[0070] This test example is used to illustrate the effects of different treatment groups on the total bacterial count on the surface of chilled chicken. The experimental method is as follows:

[0071] The chilled chicken samples treated with different antibacterial agents in Example 1, Example 2 and Comparative Example 1 were stored at 4° C. for 8 days, and the microorganisms of the samples were detected every 4 days. The specific operation was as follows:

[0072] Add 0.9% saline to the sterile bag, with a mass ratio of saline to meat of 1:1. Place the sterile bag in a constant temperature oscillator and oscillate for 10 minutes at a speed of 300 r / min. Dilute the mixture 10 times according to the gradient. Select the appropriate gradient and add 1 mL of the dilution dropwise to the total bacterial count and coliform group test plate. Incubate in a constant temperature incubator at 37°C for 48 hours. Figure 2-Figure 3 .

[0073] Depend on Figure 2 It can be seen from the data that with the extension of storage time, the total colony count and coliform count on the surface of chilled chicken increased significantly (p<0.05). Under the same storage conditions, the total colony count on the surface of chilled chicken samples in the NaClO group, PAW group, and PACA group increased from 4.11, 3.34, and 2.98 lg CFU / g on the 0th day to 6.94, 6.19, and 4.27 lg CFU / g on the 8th day, respectively; compared with the NaClO group, the PAW group and the PACA group can significantly inhibit the growth of the total microbial colony count of chilled chicken. It can be seen that treating chilled chicken with the plasma-activated water prepared in Preparation Example 1 and the plasma-activated citric acid solution prepared in Preparation Example 2 of the present invention can extend its shelf life, among which the plasma-activated citric acid solution has the best antibacterial effect.

[0074] Depend on Figure 3The results of the study revealed changes in coliform bacteria. Under the same storage conditions, the surface coliform counts of chilled chicken samples in the NaClO, PAW, and PACA groups increased from 2.82, 2.75, and 2.26 lg CFU / g on day 0 to 5.06, 4.62, and 3.14 lg CFU / g on day 8, respectively. On day 0, PAW treatment had no significant effect on the initial coliform counts in the samples (p>0.05). However, with extended storage, the inhibitory effects of the PAW and PACA groups on surface coliform counts in chilled chicken significantly increased.

[0075] It is shown that the method for extending the shelf life of chilled chicken of the present invention can effectively inhibit the activity of total bacterial colonies and Escherichia coli during storage of chilled chicken, thereby extending the shelf life of chilled chicken.

[0076] Test Example 2

[0077] This test example is used to illustrate the effects of different treatment groups on TBARS in chilled chicken. The experimental method is as follows:

[0078] The determination was carried out according to the second method of spectrophotometry in accordance with the national standard GB 5009.181-2016 "National Food Safety Standard Determination of Malondialdehyde in Food". The results are shown in Figure 4 .

[0079] Depend on Figure 4 It can be seen that as the storage days increase, the malondialdehyde content of the chilled chicken samples in the different treatment groups increases significantly (P<0.05). The malondialdehyde content of the chilled chicken samples in the NaClO group, PAW group, and PACA group increases from 0.15, 0.14, and 0.14 mg / kg on day 0 to 0.86, 0.55, and 0.41 mg / kg on day 8, respectively. On day 0, there was no significant difference in the malondialdehyde content of the chilled chicken samples in the different treatment groups, but on days 4 and 8, the malondialdehyde content of the chilled chicken samples in the PAW group and PACA group was significantly lower than that in the NaClO group. This shows that compared with the NaClO group, the PAW group and the PACA group can significantly inhibit the increase in the malondialdehyde content of chilled chicken during storage, that is, the method of the present invention inhibits the generation of lipid peroxidation substances during storage of chilled chicken.

[0080] Test Example 3

[0081] This test example is used to illustrate the effects of different treatment groups on nitrite on the surface of chilled chicken. The experimental method is as follows:

[0082] The determination was carried out according to the second method of spectrophotometry in accordance with the national standard GB 5009.33-2016 "Determination of nitrite and nitrate in food". The results are shown in Figure 5 .

[0083] Depend on Figure 5As shown in the results of a study, plasma-activated water contains high levels of nitrite. While nitrite has a certain antibacterial effect, excessive nitrite levels can also pose food safety concerns. Therefore, the effect of plasma-activated water on the surface nitrite content of chicken was determined. The results showed that treatment with PAW and PACA significantly increased the surface nitrite content of chilled chicken (p < 0.05).

[0084] Under the same storage conditions, the nitrite content on the surface of chicken samples in the NaClO group gradually increased with the extension of storage time, but remained at a low level, only increasing from 3.69 mg / kg on day 0 to 4.19 mg / kg on day 8. The nitrite content on the surface of chicken samples in the PAW and PACA groups gradually decreased, from 18.5 and 21.43 mg / kg on day 0 to 6.73 and 10.05 mg / kg, respectively. The reason for this phenomenon may be that nitrite is gradually reduced to nitric oxide during storage, thus reducing the nitrite content.

[0085] While there are no regulations in China regarding nitrite content in fresh meat, international laws and regulations stipulate a detection limit of 30 mg / kg for nitrite in meat products. Nitrite levels in chilled chicken samples treated with plasma-activated solution decreased with storage time, remaining within a safe range.

[0086] In summary, the method for extending the shelf life of chilled chicken of the present invention comprises the following steps: plasma-treating a plasma-activated solution preparation liquid by a plasma-activated solution preparation device to obtain a plasma-activated solution, wherein reactive oxygen species and reactive nitrogen species are formed in the plasma-activated solution. The plasma-activated solution is used to soak the chilled chicken, which can significantly inhibit the growth and reproduction of microorganisms on the surface of the chilled chicken, slow down lipid oxidation, and is beneficial to maintaining the storage quality of the chilled chicken and extending the shelf life of the chilled chicken.

[0087] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0088] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0089] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for extending the shelf life of chilled chicken, characterized in that: The method comprises: 1) preparing a plasma activation solution; 2) soaking the chilled chicken in the plasma activation solution described in step 1); 3) Draining the chilled chicken in step 2) and packaging for storage.

2. The method according to claim 1, characterized in that In step 1), the plasma activated solution is obtained by treating a plasma activated solution preparation solution with a plasma activated solution preparation device for 15-30 minutes.

3. The preparation method according to claim 2, characterized in that The plasma activated solution preparation equipment comprises: A reaction chamber, which is a hollow cavity closed at both ends and used for reacting the plasma activation solution preparation liquid with the plasma; A solution inlet is provided at the upper left of the reaction chamber and is connected to the reaction chamber through a pipeline for inputting a plasma activation solution preparation solution; Two plasma jet devices, which are arranged in parallel above the reaction chamber and connected to the reaction chamber through a pipeline, and are used to generate and process plasma; A solution outlet is provided directly below the reaction chamber and connected to the reaction chamber via a pipeline for outputting the treated plasma-activated solution; A switch is provided outside the reaction chamber and is used to operate and control the entire device.

4. The method according to claim 2 or 3, characterized in that The plasma activation solution preparation solution consists of water and / or citric acid solution.

5. The method according to claim 4, characterized in that The concentration of the citric acid solution is 0.05-1.0 wt %.

6. The method according to any one of claims 2 to 5, characterized in that The operating conditions of the plasma activated solution preparation equipment include: using air as the working carrier, a flow rate of 30-40 L / min, an equipment operating voltage of 220 V, a frequency of 50 Hz, and a discharge distance of 6 mm.

7. The method according to any one of claims 1 to 6, characterized in that In step 2), the material-liquid ratio of the plasma activated solution to the chilled chicken is 1:1.5-2.

8. The method according to any one of claims 1 to 7, characterized in that In step 2), the soaking treatment time is 10-20 minutes.

9. The method according to any one of claims 1 to 8, characterized in that In step 3), the packaging and storage conditions include: sealing the drained chilled chicken in a sterile bag and storing it at a temperature of 0-4°C.

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