A device and method for preserving perishable packaged food based on low-temperature plasma

Abstract

The present invention belongs to the field of food preservation, and discloses a perishable packaged food preservation device based on low-temperature plasma, including: a packaging box, a cabinet, a plasma generator, a shell, a conveyor and a rack, wherein: the plasma generator includes: parallel electrodes, a discharge medium, a discharge area, an electrode lead, a transformer and a pulse power supply; the conveyor includes a conveyor belt and a hub, the hub is fixed at both ends of the cabinet, and the motor drives the hub to rotate; the transformer includes a high-voltage outlet terminal and a heat dissipation pipe; the heat dissipation pipe is located on the outside of the transformer, and the high-voltage outlet terminal is connected to the parallel electrodes through the electrode lead; the packaging box is located at the rear of the cabinet, the rack is located in front of the cabinet, the transformer is located on one side of the cabinet, and a shell is installed above the cabinet. The sterilization process of the present invention is carried out at normal temperature and pressure, and the plasma has little effect on the quality of food, which can effectively extend the shelf life of perishable food. The present invention also discloses a perishable packaged food preservation method based on low-temperature plasma.

Description

Technical Field

[0001] The invention relates to the field of food preservation, and in particular to a device and method for preserving perishable packaged food based on low-temperature plasma. Technical Background

[0002] Perishable packaged foods mainly include fruits and vegetables and aquatic products. Fruits and vegetables are rich in vitamins, minerals and vitamins, but their production is highly seasonal and regional, making them very easy to spoil; aquatic products are rich in amino acids and unsaturated fatty acids and have a relatively low fat content, making them popular among people. However, aquatic products have high water and protein content, making them very easy to spoil under the action of microorganisms and endogenous enzymes, resulting in high losses in manpower and financial resources. The purpose of this type of food packaging is to protect the quality of food during circulation and storage, and to prevent it from spoiling, being damaged or being contaminated by the outside world. Sterilization is performed after the bag is sealed so that the food is no longer in contact with the external environment, reducing the risk of contamination.

[0003] At present, the main preservation technologies for perishable foods include refrigeration, preservatives, and irradiation. Refrigeration preservation is not enough to completely inhibit microorganisms because its storage temperature is not high enough; preservatives have residual problems, which pose potential safety risks and may cause certain harm to the human body; the dose of irradiation is difficult to control, which will cause a certain degree of radioactive pollution. In addition, ultraviolet rays will cause the denaturation of certain proteins in food and even cause harm to the body. Low-temperature plasma technology, a simple, easy and low-energy technology, can be used to generate plasma in sealed perishable packaging food materials to inactivate microorganisms, with high efficiency and short action time. In addition, this method is easy to expand to continuous food industry processing operation units, and can prevent the contamination of packaging materials, more effectively extend the shelf life of perishable foods, and also has a strong reduction effect on fungi and can degrade pesticide residues, making packaged foods more green and safe.

[0004] At present, patent CN210382453U (see Suzhou Fengyuanbao Agricultural Technology Co., Ltd.'s Chinese utility model patent application "A continuous fruit and vegetable preservation plasma treatment equipment", published on April 24, 2020) discloses a continuous fruit and vegetable preservation plasma treatment equipment, but the equipment will cause mechanical damage to the fruits and vegetables during the process of falling from the first roller row to the second roller row. Patent CN110946178A (see Dalian University of Technology's Chinese invention patent application "An atmospheric pressure low-temperature plasma fruit preservation device", published on April 3, 2020, publication number CN110946178A) discloses an atmospheric pressure low-temperature plasma fruit preservation device, but the equipment adjusts the height of the base to achieve the transportation of fruits and vegetables with the help of the gravity of the fruits and vegetables, which is a cumbersome process and has poor results. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a perishable packaged food preservation device based on low-temperature plasma.

[0006] The invention also provides a method for preserving perishable packaged food based on low-temperature plasma.

[0007] The present invention is implemented by the following technical solutions:

[0008] A perishable packaged food preservation device based on low-temperature plasma, comprising: a packaging box, a cabinet, a plasma generator, a shell, a conveying device and a storage rack, wherein:

[0009] The plasma generator comprises: parallel electrodes, a discharge medium, a discharge zone, electrode lead wires, a transformer and a pulse power supply, wherein: the electrode lead wires are connected to the parallel electrodes, the discharge medium is fixed inside the parallel electrodes, the discharge zone is between the discharge mediums, and there is a conveyor belt inside the discharge zone;

[0010] The conveyor device includes a conveyor belt and a wheel hub, the wheel hubs are fixed at both ends of the cabinet, and the motor drives the wheel hubs to rotate, thereby driving the circular motion of the conveyor belt; the conveyor device is located in the middle of the parallel electrodes and is fixed on the cabinet;

[0011] The transformer includes a high-voltage outlet terminal and a heat dissipation pipe; the heat dissipation pipe is located outside the transformer, and the high-voltage outlet terminal is connected to parallel electrodes through electrode lead wires;

[0012] The packaging box is located at the rear of the cabinet, the storage rack is located at the front of the cabinet, the transformer is located at one side of the cabinet, and a shell is installed above the cabinet.

[0013] Preferably, the plasma generator adopts a dielectric barrier discharge plasma exciter, parallel electrodes are installed on both sides of the cabinet, and the transformer and the pulse power supply are connected through electrode lead wires.

[0014] Preferably, the parallel electrode material comprises copper, stainless steel or aluminum alloy.

[0015] Preferably, the parallel electrodes are 150 mm long, 30 mm wide and 20 mm thick.

[0016] Preferably, the pulse power supply adopts a microsecond pulse power supply with an output voltage of 0-50 kV, a pulse width of 1-20 μs, and a frequency of 20-50 kHz.

[0017] Preferably, the discharge region is located between two parallel electrodes, and the discharge region is a rectangular cavity with a length of 150 mm and a width of 400 mm.

[0018] Preferably, the discharge medium is quartz glass or epoxy resin with a thickness of 3 mm.

[0019] Preferably, the dimensions of the cabinet are 1500 mm×60 mm×500 mm, and the dimensions of the shell are 1000 mm×60 mm×400 mm.

[0020] Preferably, a pulley is installed under the cabinet.

[0021] A method for preserving perishable packaged food based on low-temperature plasma, comprising:

[0022] S1. Start the transport device to transport the perishable packaged food on the conveyor belt via the conveyor device;

[0023] S2, starting the plasma generator so that the plasma excitation device generates plasma to the air in the perishable packaged food and the air between the parallel electrodes;

[0024] S3. After plasma treatment, perishable packaged food is transported to the tray and enters the next process.

[0025] The advantages and beneficial effects of the present invention include:

[0026] (1) The present invention uses a conveyor belt to transport packaged food through two parallel electrodes of a plasma generator. The air in the packaging material and the air between the two parallel electrodes are excited to produce plasma active components, which sterilize the food to achieve the effect of preserving freshness. At the same time, the packaging material is sterilized to prevent secondary contamination of the food. The sterilization process is carried out at normal temperature and pressure. The plasma has little effect on the quality of the food, effectively extending the shelf life of perishable foods.

[0027] (2) The perishable food preservation device of the present invention is mainly used for preserving perishable packaged food. While sterilizing the perishable food, the packaging material is also sterilized, thereby avoiding contamination of the food by the packaging material and secondary contamination of the external environment.

[0028] (3) The perishable food preservation device of the present invention adopts low-temperature plasma for treatment. The treatment process is carried out at room temperature and pressure, which has little impact on food quality and maintains its green and original ecology. The plasma can also degrade residual drugs on the surface of food and extend the shelf life of the food.

[0029] (4) The perishable food preservation device of the present invention adopts a conveyor belt and a wheel hub transmission device, and the transportation process is stable, safe and efficient, which realizes the continuous large-scale sterilization and preservation treatment of perishable packaged food in the production line. In addition, a pulley is installed at the bottom of the device, and the device is flexible and convenient to move, providing convenient conditions for industrial production.

[0030] (5) The perishable food preservation device of the present invention adopts a pulsed plasma exciter. The pulsed power supply can provide a higher power density, generate atmospheric pressure plasma with high reaction efficiency, and the reaction system is close to room temperature, avoiding the adverse effects of overheating. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is one of the structural schematic diagrams of a perishable packaged food preservation device based on low-temperature plasma in one embodiment.

[0032] Figure 2 This is the second structural schematic diagram of a perishable packaged food preservation device based on low-temperature plasma in an embodiment.

[0033] Figure 3 FIG. 1 is a schematic diagram of a plasma generator in one embodiment.

[0034] Figure 4 This is a graph showing the change in the total number of bacterial colonies during storage of packaged, boiled, ready-to-eat prawns after being treated by a fresh-keeping device in an embodiment.

[0035] Figure 5 This is a graph showing the change in the decay rate of packaged strawberries during storage after being treated by a fresh-keeping device in an embodiment. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0037] Example 1

[0038] like Figure 1 , 2 As shown, a perishable packaged food preservation device based on low-temperature plasma includes: a packaging box 1, a cabinet 9, a plasma generator, a shell 8, a conveying device and a shelf 10, wherein:

[0039] Plasma generators such as Figure 3 The figure includes: parallel electrodes 11, discharge medium 12, discharge area 13, electrode lead wires 14, transformer 6 and pulse power supply, wherein: the electrode lead wires 14 are connected to the parallel electrodes 11, the discharge medium 12 is fixed on the inner side of the parallel electrodes 11, the discharge area 13 is between the discharge medium 12, and the conveyor belt 2 is arranged in the discharge area 13.

[0040] The conveying device includes a conveyor belt 2 and a hub 3. The hubs are fixed at both ends of the cabinet. The motor drives the hubs to rotate, thereby driving the circular motion of the conveyor belt, so as to transport the perishable packaged food from the packaging box 1 to the storage rack 10, thereby transmitting the perishable packaged food. The conveying device is located in the middle of the parallel electrodes and is fixed on the cabinet.

[0041] The transformer 6 comprises a high voltage outlet terminal 5 and a heat dissipation pipe 7. The heat dissipation pipe is located outside the transformer, and the high voltage outlet terminal is connected to parallel electrodes through electrode lead wires.

[0042] The packaging box is located at the rear of the cabinet, the storage rack 10 is located at the front of the cabinet, the transformer is located at one side of the cabinet, and a housing is installed above the cabinet. A pulley 4 is installed below the cabinet 9.

[0043] In a preferred embodiment, the plasma generator adopts a dielectric barrier discharge plasma exciter, parallel electrodes are installed on both sides of the cabinet, and the transformer and the pulse power supply are connected through electrode lead wires. The parallel electrode material includes copper, stainless steel or aluminum alloy. The parallel electrode is 150 mm long, 30 mm wide and 20 mm thick.

[0044] The pulse power supply uses a microsecond pulse power supply with an output voltage of 0-50kV, a pulse width of 1-20μs, and a frequency of 20-50kHz. A good preservation effect can be achieved after processing for 4-5 minutes.

[0045] The discharge medium of the plasma generator is located inside the parallel electrodes. The discharge zone is located between the two parallel electrodes and is a rectangular cavity with a length of 150 mm and a width of 400 mm.

[0046] The conveyor belt is 3-4cm wide and made of rubber.

[0047] The discharge medium is quartz glass or epoxy resin, 3 mm thick, and is located on the inner side of the parallel electrodes.

[0048] The dimensions of the cabinet are 1500mm×60mm×500mm, and the dimensions of the shell are 1000mm×60mm×400mm.

[0049] A method for preserving perishable packaged food based on low-temperature plasma, comprising:

[0050] S1. Start the transport device to transport the perishable packaged food on the conveyor belt via the conveyor device;

[0051] S2, starting the plasma generator so that the plasma excitation device generates plasma to the air in the perishable packaged food and the air between the parallel electrodes;

[0052] S3. After plasma treatment, perishable packaged food is transported to the tray and enters the next process.

[0053] Example 2

[0054] This embodiment takes the preservation of boiled and ready-to-eat shrimps in vacuum packaging as an example. Specifically:

[0055] A method for preserving perishable packaged food based on low-temperature plasma, comprising:

[0056] Step 1): starting the transport device to transport the vacuum-packed cooked instant shrimps on a conveyor belt via the conveyor device;

[0057] Step 2): starting a plasma generator to generate plasma to the air in the packaging material and the air between the parallel electrodes;

[0058] Step 3): The vacuum-packed cooked instant shrimps are transported to a tray after being treated with plasma and enter the next secondary packaging process.

[0059] Start the transport device and the plasma generator. When the conveyor belt transports the packaged shrimps through the parallel electrodes, the parallel electrodes excite the air in the packaging material and the air between the two parallel electrodes to produce plasma active components, which sterilize the shrimps to achieve the effect of preservation. At the same time, the packaging materials are sterilized to prevent secondary contamination of the shrimps. A certain amount of packaged shrimps were selected as the control group, and the same amount of packaged shrimps from the same batch were selected as the experimental group. The packaged shrimps in the experimental group were treated at 30kV for 5 minutes, and the control group was not treated in any way. The two groups of packaged shrimps were stored at room temperature. The total number of colonies of the shrimps was measured after storage for 0, 15, 30, 45, 60, 75, and 90 days. The results are as follows Figure 4 As shown, it can be proved that low-temperature plasma has significant sterilization effect and can effectively extend the shelf life of cooked ready-to-eat shrimps.

[0060] Example 3

[0061] This embodiment is described by taking bagged strawberries as an example. Specifically:

[0062] A method for preserving perishable packaged food based on low-temperature plasma, comprising:

[0063] Step 1): starting the transport device to transport the bagged strawberries on the conveyor belt via the conveyor device;

[0064] Step 2): starting a plasma generator to generate plasma to the air in the packaging material and the air between the parallel electrodes;

[0065] Step 3): After being treated with plasma, the bagged strawberries are transported to the tray and enter the next secondary packaging process.

[0066] Start the transport device and the plasma generator. When the conveyor belt transports the bagged strawberries passing between the parallel electrodes, the air in the packaging material and the air between the two parallel electrodes are excited to produce plasma active components, which sterilize the strawberries to achieve the effect of preserving freshness. At the same time, the packaging materials are sterilized to prevent secondary contamination of the strawberries. A certain amount of packaged strawberries are selected as the control group, and the same amount of packaged strawberries from the same batch are selected as the experimental group. The packaged strawberries in the experimental group are treated at 30kV for 5 minutes, and the control group is not treated in any way. The two groups of packaged strawberries are stored at room temperature. The rot rate of strawberries is measured after 0, 1, 3, 5, and 7 days of storage, respectively. The results are as follows: Figure 5 As shown, it can be proved that low-temperature plasma has significant sterilization effect and can effectively extend the shelf life of packaged strawberries.

[0067] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A perishable packaged food preservation device based on low-temperature plasma, using a perishable packaged food preservation method based on low-temperature plasma, characterized in that: The perishable packaged food preservation device based on low-temperature plasma comprises: a packaging box, a cabinet, a plasma generator, a shell, a conveying device and a storage rack, wherein: The plasma generator comprises: parallel electrodes, a discharge medium, a discharge zone, electrode lead wires, a transformer and a pulse power supply, wherein: the electrode lead wires are connected to the parallel electrodes, the discharge medium is fixed inside the parallel electrodes, the discharge zone is between the discharge mediums, and there is a conveyor belt inside the discharge zone; The conveyor device includes a conveyor belt and a wheel hub, the wheel hub is fixed at both ends of the cabinet, and the motor drives the wheel hub to rotate, thereby driving the circular motion of the conveyor belt; the conveyor device is located in the middle of the parallel electrodes and is fixed on the cabinet; The transformer includes a high-voltage outlet terminal and a heat dissipation pipe; the heat dissipation pipe is located outside the transformer, and the high-voltage outlet terminal is connected to parallel electrodes through electrode lead wires; The packaging box is located at the rear of the cabinet, the shelf is located at the front of the cabinet, the transformer is located at one side of the cabinet, a housing is installed above the cabinet, and a pulley is installed below the cabinet; The plasma generator uses a dielectric barrier discharge plasma exciter, parallel electrodes are installed on both sides of the cabinet, and the transformer and pulse power supply are connected through electrode lead wires; The pulse power supply adopts a microsecond pulse power supply with an output voltage of 0-50kV, a pulse width of 1-20μs, and a frequency of 20-50kHz; Low-temperature plasma-based methods for preserving perishable packaged foods include: S1. Start the transport device to transport the perishable packaged food on the conveyor belt via the conveyor device; S2, starting the plasma generator so that the plasma excitation device generates plasma to the air in the perishable packaged food and the air between the parallel electrodes; S3, the perishable packaged food is transported to the tray after being treated by plasma and enters the next process; The packaged food is transported by a conveyor belt through the two parallel electrodes of the plasma generator. The air in the packaging material and the air between the two parallel electrodes are excited to produce plasma active components, which sterilize the food to achieve the effect of preserving freshness. At the same time, the packaging material is sterilized to prevent secondary contamination of the food. The sterilization process is carried out at normal temperature and pressure.

2. The perishable packaged food preservation device according to claim 1, characterized in that: Parallel electrode materials include copper, stainless steel or aluminum alloy.

3. The perishable packaged food preservation device according to claim 1, characterized in that: The parallel electrodes are 150 mm long, 30 mm wide and 20 mm thick.

4. The perishable packaged food preservation device according to claim 1, characterized in that: The discharge area is located between two parallel electrodes and is a rectangular cavity with a length of 150 mm and a width of 400 mm.

5. The perishable packaged food preservation device according to claim 1, characterized in that: The discharge medium is quartz glass or epoxy resin, 3mm thick.

6. The perishable packaged food preservation device according to claim 1, characterized in that: The dimensions of the cabinet are 1500mm×60mm×500mm, and the dimensions of the shell are 1000mm×60mm×400mm.

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