CN115943989A - Integrated circulating freeze thawing device and application thereof in freeze thawing of fresh food - Google Patents

Abstract

The invention relates to an integrated circulating freeze thawing device and application thereof in freeze thawing of fresh food, belonging to the technical field of food freezing processing. Comprises a freezing chamber, a thawing chamber, a lifting component, a temperature acquisition device, a controller and an argon/krypton/xenon mixed gas combined injection component; the freezing chamber and the thawing chamber are vertically distributed and are connected by the lifting component and the hose, the lifting component consists of a lifting device and a sample tray, the sample tray is connected with the lifting device by a sample tray frame, and the lifting device is used for moving the sample tray to a required position in the cavity; the controller is connected with the inner cavity through the temperature acquisition device, and the controller is also connected with the combined injection assembly. According to the invention, the mixed gas composed of liquid nitrogen and argon/krypton/xenon mixed gas is used for freezing food materials, the electrostatic field and the far infrared technology are used for unfreezing, the precise temperature control is matched, the use is convenient and fast, and the effect is better.

Description

Integrated circulating freeze thawing device and application thereof in freeze thawing of fresh food

Technical Field

The invention relates to an integrated circulating freeze thawing device and application thereof in freeze thawing of fresh food, belonging to the technical field of food freezing processing.

Background

Freezing is one of the most common techniques for preserving food products with the aim of maintaining their original nutritional and organoleptic properties. During freezing, water molecules form ice crystals, the original combination state of food components and water is changed, and the characteristics of the food are usually changed remarkably. Thawing is the reverse process of freezing, and solid ice is reconverted to liquid water. However, the frozen food cannot be restored to its original state because the damage of the frozen food to the water binding state is irreversible. The cell and tissue structure of frozen and thawed food is changed, and the change of hardness, viscosity, gel structure and the like is often accompanied. Studies have shown that some foods have improved processing characteristics after freeze-thaw cycling.

Van willow and the like (patent number: 202110761738. X) disclose a method for processing pumpkin pulp by ultrasonic combined circulating freeze thawing, compared with a seed pumpkin pulp product directly subjected to far infrared drying without circulating freeze thawing, the method improves the far infrared drying efficiency of the seed pumpkin, shortens the drying time by 25 to 40 percent, has high product appearance integrity rate, is closer to the color of fresh seed pumpkin pulp, has small wrinkle shrinkage rate, moderate hardness and brittleness, and has the content of free phenols and the content of monomer phenols which are obviously higher than those of the conventional far infrared drying. Researches by Wanlan and the like of agricultural science institute in Hubei province show that starch can generate an ordered network structure after being subjected to freeze-thaw cycle treatment, network gaps become larger along with the increase of cycle times, and the network structure forms and destroys the characteristic change of a corresponding gel part. The water-separating rate of the starch gel is in a descending trend along with the increase of the number of freeze-thaw cycles. The water precipitation rate of the rice starch is obviously reduced after 2 times of freeze-thaw cycle treatment, which shows that the network structure of the gel starch is strengthened to form a water cage structure with certain strength, and is beneficial to reducing the gelatinization temperature of the rice during cooking. In addition, due to the effects of expansion with heat and contraction with cold, the brown rice bran layer structure is improved through circulating freeze thawing treatment, and the structure components of the brown rice surface layer are changed, so that the water absorption of the brown rice during soaking is improved, and the gelatinization temperature of the brown rice during cooking is reduced. Courage and the like (patent number: 201711277795.0) disclose a rapid processing method of circulating freeze-thaw nutritional healthy palatable brown rice, which effectively solves the problems that the existing brown rice is not easy to cook and has poor taste and the like. Wujinxuan et al (patent No. 202221014889.5) disclose a folium mori repeated freeze-thawing device, and the folium mori after the freeze-thawing operation is used for preparing folium mori tea, which not only can increase the dissolution amount of DNJ in the folium mori tea, but also keeps the emerald green appearance of the folium mori tea. The above studies and patents show the beneficial effects of freeze-thaw operations. However, the traditional freezing method has the disadvantages of slow speed, low efficiency, large ice crystals formed by freezing, serious damage to the quality of the food and the like. The traditional unfreezing technology comprises air unfreezing, vacuum unfreezing, immersion unfreezing and the like, and has the defects of low efficiency, high cost, inconvenience in use and the like. At slower thawing rates, the quality attributes of the frozen food product are significantly reduced and microbial growth is also significantly accelerated. In addition, the separate freezing and thawing operation is difficult to realize, which is not favorable for the freezing and thawing cycle.

The quick freezing can effectively reduce the damage of freezing to food, and the product temperature can rapidly cross the maximum ice crystal generation zone, thereby preventing the migration of water molecules and finally forming uniform and fine ice crystals, so the quick freezing is advocated in the field of freezing at home and abroad. The lowest temperature of the liquid nitrogen can reach-198 ℃, the quick freezing of the food can be realized, the quality of the frozen product is improved, and the liquid nitrogen is widely applied to the quick freezing of the food. However, there are still many problems with liquid nitrogen used for quick freezing of raw and fresh food materials. For example, there is a phenomenon of frost cracking for some fruits due to an excessively high freezing speed; the low-efficiency unfreezing mode causes the phenomena of ice crystal growth, recrystallization and the like in the unfreezing process of the fresh food; the activity of enzyme and microorganism of the fresh food is enhanced after freezing and thawing, the quality of the product is rapidly reduced, and the like; the larger freezing and thawing equipment occupies a large volume and is inconvenient to use. On the basis of quick freezing, in recent years, in order to obtain better freezing and thawing effects, more and more research has been focused on assisting the freezing and thawing operation using physical field techniques such as ultrasonic waves, microwaves, far infrared rays, high voltage, electric fields, magnetic fields, radio frequencies, and the like. The effective physical field auxiliary or cooperative application can accelerate the freezing and thawing process, further improve the product quality of the quick-frozen food and improve the thawed quality of the frozen product. In addition, there have been some studies focused on some new liquefied gases to achieve quick freezing of food products.

Zhang 24924et al (patent No. 202210166852.2) disclose a static magnetic field assisted liquefied CO2 pulse freezing device and a pressurized high-efficiency freezing method. The quick freezing device adopts liquefied CO2 as a freezing medium, is provided with static magnetic field generating equipment to assist in freezing, and can reduce the size of ice crystals. The freezing method comprises the steps of evacuation, precooling, CO2 pressurization, magnetic field assisted quick freezing and deep freezing. However, the freezing equipment of the invention adopts liquefied carbon dioxide as a refrigerating medium, the lowest temperature can only reach-78.3 ℃, and the quick-freezing effect is difficult to achieve when the size of the frozen product is larger. The liquefied CO2 is sprayed out through the combined fluid nozzle, the flow is small, and the effect of freezing the materials on a large scale is difficult to achieve. In addition, the freezing equipment of the invention only has one freezing chamber, which can not realize the independent pre-freezing pretreatment operation of fresh food materials and has no unfreezing function. The ejected CO2 can only be discharged into the surrounding environment, and has no recycling function.

With regard to food thawing, many studies show that both infrared and electric fields can have certain effects in the thawing process. Chen et al comparatively studied the thawing efficacy of infrared and microwave technology on frozen green pepper, carrot and cantaloupe, and the results showed that the infrared effect can accelerate the thawing process of frozen fresh food. Bissoyi and other researches show that the infrared irradiation has more advantages on cell thawing and the cell thawing survival rate is higher. A method for preparing parched chestnut by using far infrared ray for thawing is disclosed (patent No. 200510088882.2), which utilizes far infrared ray to thaw frozen chestnut at 170-230 deg.C for 30-60 minutes to inhibit the generation of microorganism and eliminate peculiar smell during thawing process. Korean blue (patent number: 201721374827.4) discloses a far infrared low-temperature thawing device, which comprises a box body, a temperature and humidity sensor, a humidifying device, a far infrared generating tube and the like, wherein the far infrared generating tube is a carbon black wire infrared quartz light wave heating tube. Highly, 30889, 25035, (patent No. 202121798112.8) discloses a quick thawing cabinet based on a low-frequency and high-voltage electric field, the electric field has protection and penetration effects on frozen products, the surface and the interior are simultaneously thawed, the thawing speed and quality are improved, and no residual frozen area exists. Sulaijin et al (patent number: 202011227858.3) disclose a method for quickly thawing aquatic products based on electric field synergy, which comprises the steps of low-temperature low-voltage electrostatic field thawing treatment, low-temperature high-voltage electrostatic field thawing treatment, high-temperature high-voltage electrostatic field thawing treatment and high-temperature low-voltage electrostatic field thawing treatment until the aquatic products are completely thawed.

The above studies and patents show the beneficial effects of far infrared and electrostatic fields in assisting thawing, however, the patent disclosure related to the combined effect of far infrared and electrostatic fields is not shown, and the invention creation of the integrated freezing and thawing machine integrating the freezing and thawing functions is not related.

Argon and krypton are low-cost inert gases, and some researches and patents report the beneficial effect of using argon or krypton to keep fresh of fresh foods. Bihongtao (patent number: 201910175956.8) discloses a method for preserving cordyceps sinensis by atmosphere packaging with argon gas, wherein the atmosphere packaging is carried out by using mixed gas containing argon gas, so that the weight loss rate of the cordyceps sinensis can be remarkably inhibited from decreasing, the content of soluble protein can be slowed down from decreasing, the water activity can be delayed from increasing, and the activity of polyphenol oxidase can be delayed from increasing. Dan Wu et al (2021) adopt nano zinc oxide to jointly pressurize argon gas to treat fresh-cut oranges, and experimental results show that the argon gas joint treatment obviously prolongs the fresh-keeping period of the fresh-cut oranges. Chengxiag et al (patent number: 201810945715.2) disclose a fresh-keeping method for rapid moisture structuring of fresh-cut fruits and vegetables, comprising peeling and cutting raw materials of fruits and vegetables, charging argon, krypton, nitrogen or carbon dioxide mixed gas, and then subjecting the raw materials to high-pressure treatment to rapidly structure the moisture on the surfaces and tissues of the fresh-cut fruits and vegetables and reduce the activity of water molecules. Zhang 24924i et al (patent number: 201710028514.1) disclose a method for prolonging the shelf life of refrigerated storage by combining the shelling and conditioning antibacterial activity fresh-keeping with the modified atmosphere fresh-keeping, and the invention provides a modified atmosphere fresh-keeping technology suitable for shrimp meat based on inert gas, and argon or krypton is used for replacing conventional nitrogen.

However, the above-disclosed studies and patents all use argon or krypton for the preservation of fresh foods. The method and the equipment for using the argon/krypton/xenon mixed gas for freezing and thawing the fresh food are not reported.

Disclosure of Invention

In order to solve the problems, the invention provides an integrated circulating freezing and thawing device, which comprises a freezing chamber, a thawing chamber, a lifting assembly, a temperature acquisition device, a controller and an argon/krypton/xenon mixed gas combined injection assembly, wherein the freezing chamber is provided with a freezing chamber and a thawing chamber;

the freezing chamber and the thawing chamber are vertically distributed.

The controller is connected with the temperature acquisition device, and the temperature acquisition device can monitor the temperature in the device and feed back information to the controller;

the controller controls the movement of a lifting device, and the lifting assembly is arranged between the thawing chamber and the freezing chamber and can move freely; the lifting assembly consists of a lifting device and a sample tray, and the sample tray is connected with the lifting device through a sample tray frame; elevating gear drives the sample tray and removes to the freezer or unfreeze the room, still be equipped with the hose between freezer and the unfreeze room for the freezer transmits remaining mist to the unfreeze room.

The controller is also connected with the combined injection assembly, and when the freezing operation is carried out, the controller controls the combined injection assembly to inject the mixed gas to the freezing chamber.

The combined injection assembly is connected with the freezing chamber, the argon/krypton/xenon mixed gas combined injection assembly comprises an argon/krypton/xenon mixed gas injection device, a liquid nitrogen injection device, an argon/krypton/xenon mixed gas dynamic proportion adjusting device, an air compressor, a pressure relief valve and a vacuum pump, the dynamic proportion and the pressure of the mixed gas can be controlled according to conditions, and the freezing effect can be controlled more accurately; the argon/krypton/xenon mixed gas injection device is also connected with the thawing chamber;

the thawing chamber comprises a far infrared generating device, an electrostatic field device and a temperature control device.

In one embodiment of the invention, the sample tray is a net structure, the material is polytetrafluoroethylene, and the height of the tray is 5cm; the sample tray frame is made of polytetrafluoroethylene, and the polytetrafluoroethylene material can reduce the interference of the sample tray and the sample tray frame on an electrostatic field and far infrared rays when the electrostatic field and the magnetic field act on a sample.

In one embodiment of the invention, the temperature acquisition device comprises a first temperature sensor and a second temperature sensor, wherein the first temperature sensor is suspended and used for sensing the temperature in the cavity of the freezing chamber or the thawing chamber; the second temperature sensor is composed of a 12-channel food plug-in temperature sensor and a 2.5mm silver-plated waterproof shielding wire, the temperature error is +/-0.15 ℃, and the second temperature sensor is connected with the sample tray and used for sensing the sample temperature in the center of the sample tray.

In one embodiment of the invention, the argon/krypton/xenon mixed gas injection device and the liquid nitrogen injection device are respectively provided with a nozzle, a flow control valve and a gas inlet heat preservation pipe, and the opening and the closing of the nozzles are controlled by an electromagnetic valve, the two nozzles inject mixed gas consisting of argon/krypton/xenon mixed gas and liquid nitrogen into the freezing chamber through the two gas inlet heat preservation pipes, and the flow control valve controls the flow; the freezing chamber is provided with a rear fan and is used for stirring the gas in the whole cavity so as to ensure that the temperature is uniformly distributed; the freezing chamber is also provided with a rear-mounted heat preservation pipe which is connected with the external environment.

In one embodiment of the invention, the far infrared generating device comprises 4 infrared tubes, the maximum power is 700W multiplied by 4, the infrared heating working mode is intermittent, and the infrared tubes are paved on two sides of the inner wall of the thawing chamber; the electrostatic field device is a bur electrode plate, the maximum 50kV voltage is generated by discharging electricity outwards from each point corona electrode, the distance between the bur plate and the upper and lower sample supports is 10cm, and the electrostatic field acting on the food materials is 0-5 kV/cm; the outer layers of the far infrared generating device and the electrostatic field device are both provided with an electrostatic shielding device and a protection device, so that the far infrared generating device and the electrostatic field device can work simultaneously and do not interfere with each other.

In one embodiment of the invention, the temperature control device comprises a heating plate and a refrigeration compressor, and the temperature control device is also connected with the controller, so that the accurate temperature control of 0-45 ℃ in the thawing cavity can be realized.

The invention also provides an application of the integrated circulating freeze-thawing device, which comprises the following steps:

the method comprises the following steps: pretreating food materials under micro-pressure: firstly, cleaning, peeling, cutting, blanching and color protecting food materials, then moving the sample tray into the unfreezing chamber, placing a sample on the sample tray, vacuumizing the whole unfreezing chamber by using a vacuum pump, introducing argon/krypton/xenon mixed gas with the relative pressure of 0-0.03 MPa into the unfreezing chamber by using the argon/krypton/xenon injection device to realize the argon/krypton/xenon micro-pressurization treatment of fresh food materials before freezing, and forming a cage-shaped gas hydrate by using pressurized inert gas argon/krypton/xenon mixed gas and fresh food water molecules; the formation of gas hydrate in the fresh food can reduce the activity of water molecules in tissues and the activity of enzyme molecules to inhibit the metabolic activity of the fresh food, thereby achieving the protection effect in the freezing and thawing process;

step two: dynamically quick-freezing food materials by mixed gas: firstly, the food materials on the sample tray are moved to the freezing chamber by the lifting assembly, the controller starts the combined injection assembly, so that mixed gas consisting of argon/krypton/xenon mixed gas and liquid nitrogen enters the freezing chamber at a preset flow rate V1 until a temperature value fed back by the second temperature sensor reaches a preset temperature T1 in the controller, and a first-stage cooling process is completed; secondly, the input quantity of the liquid nitrogen and argon/krypton/xenon mixed gas of the combined injection assembly is increased by the controller, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor reaches the preset temperature T2 in the controller, and the quick freezing process of the maximum ice crystal generation zone of the crossing sample is finished; finally, the controller reduces the input quantity of the liquid nitrogen and argon/krypton/xenon mixed gas valve of the combined injection assembly, and reduces the flow rate of the mixed gas input into the heat-preservation hose to V3, and when the temperature value fed back by the second temperature sensor meets the preset material freezing temperature value in the controller, the input of the liquid nitrogen and argon/krypton/xenon mixed gas is closed, and all the materials in the freezing chamber are frozen;

step three: argon/krypton/xenon protected thawed food material: and the food materials on the sample tray are moved to the thawing chamber by the lifting assembly, the controller controls to input argon/krypton/xenon mixed gas for precooling, and the thawing treatment of the food materials is accelerated by adopting a method of quickly heating the far infrared irradiation surface and combining an electrostatic field.

Step four: and the residual mixed gas in the freezing chamber enters the unfreezing chamber through a hose and is used for precooling food materials during next pretreatment.

Step five: freezing and thawing other food materials: and circularly performing the operations from the first step to the fourth step.

The invention has the beneficial effects that:

1. the integrated circulating freeze-thawing device provided by the invention has the functions of pretreatment and freezing as well as high-efficiency thawing, can realize integrated operation on pre-freezing pretreatment and freeze-thawing circulation of fresh food materials, can finish pretreatment, freezing and thawing of raw materials in the same equipment, is convenient and efficient to operate, and can also be used for rapid freeze-thawing pretreatment before food drying and other processing scenes.

2. The method adopts the mixed gas consisting of the liquid nitrogen and the argon/krypton/xenon mixed gas to freeze the food materials, thereby realizing the controllable quick freezing of the fresh food materials, reducing the size of ice crystals and avoiding the frost cracking of fruits; the whole freezing and thawing process of the fresh food materials is protected by the argon/krypton/xenon mixed gas, and the water migration, the enzyme activity and the microorganism activity are limited, so that the quality of the frozen fresh food materials after thawing is effectively improved.

3. The mixed gas generated by the freezing chamber can be conveyed to the thawing chamber by a hose for cyclic utilization, and the argon/krypton/xenon mixed gas is controlled and input by matching with the controller to pre-cool and protect the food.

4. The temperature control device is provided with the controller, the temperature acquisition device, the temperature control device and the lifting assembly, so that a user can adjust operation according to temperature feedback, direct contact of hands is avoided when different steps are carried out, and the operation is convenient and fast.

5. The invention uses the combination of electrostatic field and far infrared technology to accelerate the food thawing.

6. The sample tray is of a net structure, so that mixed gas, electrostatic field discharge and far infrared generation can be better received, and temperature is uniformly distributed.

7. The invention is provided with the shielding and protecting device of the electrostatic field device and the far infrared generating device, so that the electrostatic field and the far infrared rays are not interfered with each other, and the synergistic effect is good.

8. The invention divides the freezing process into three stages, and has a thorough freezing effect.

9. The thawing chamber is also provided with a temperature control device, so that the precise temperature control of the thawing chamber can be realized.

Drawings

Fig. 1 is a schematic structural diagram of an integrated circulating freeze-thawing apparatus according to an embodiment of the present invention.

In the figure, 1: thawing chamber, 2: freezing chamber, 3: far infrared generating device, 4: lifting component, 5: electrostatic field device, 6: sample tray, 7: rear fan, 8: air compressor, 9: liquid nitrogen injection device, 10: controller, 11: argon/krypton/xenon mixed gas injection device, 12: vacuum pump, 13: first temperature sensor, 14: a second temperature sensor.

Detailed Description

Example 1

As shown in fig. 1, the invention provides an integrated circulating freeze-thawing device, which comprises a freezing chamber 2, a thawing chamber 1, a lifting assembly 4, a temperature acquisition device, a controller 10 and an argon/krypton/xenon mixed gas combined injection assembly;

the freezing chamber 2 is positioned at the lower layer of the thawing chamber 1, and an openable partition plate is arranged between the freezing chamber 2 and the thawing chamber 1; the lifting assembly 4 is arranged between the thawing chamber 1 and the freezing chamber 2 and can move freely.

The lifting assembly 4 consists of a lifting device and a sample tray 6, the sample tray 6 is of a net structure and is made of polytetrafluoroethylene, and the height of the tray is 5cm; sample tray 6 is connected by sample tray frame elevating gear, elevating gear drive sample tray 6 and remove to freezer 2 or unfreeze room 1, still be equipped with the hose between freezer 2 and the unfreezing room 1 for 2 surplus mist of freezer transmission are to unfreezing room 1.

The thawing chamber 1 comprises a far infrared generating device 3, an electrostatic field device 5 and a temperature control device.

The far infrared generating device 3 is 4 far infrared tubes laid on the inner walls of the two sides of the thawing chamber 1, the maximum power is 700W multiplied by 4, and the infrared heating working mode is intermittent.

The electrostatic field device 5 is a prickle electrode plate arranged in the middle area of the thawing chamber 1, the maximum 50kV voltage is generated by discharging each point of the corona electrode outwards, the distance between the prickle plate and the upper and lower sample supports is 10cm, and the electrostatic field acting on the fresh food samples is 0-5 kV/cm.

The outer layers of the far infrared generating device 3 and the electrostatic field device 5 are both provided with an electrostatic shielding device and a protection device, so that far infrared rays are not interfered by the electrostatic field, and the far infrared rays and the electrostatic field can work simultaneously; on the other hand, the generated electrostatic field acts on the sample directionally, and efficient thawing is realized.

The thawing chamber 1 is also internally provided with a temperature control device connected with the controller 10, and the temperature control device comprises a built-in heating plate and a refrigeration compressor, so that the accurate temperature control of 0-45 ℃ in the thawing cavity can be realized.

The controller 10 is connected with the temperature acquisition device, the temperature acquisition device comprises a first temperature sensor 13 and a second temperature sensor 14, and the first temperature sensor 13 is suspended and used for sensing the temperature in the cavity of the freezing chamber 2 or the thawing chamber 1; the second temperature sensor 14 consists of a 12-channel food plug-in temperature sensor and a 2.5mm silver-plated waterproof shielding wire, the temperature error is +/-0.15 ℃, and the second temperature sensor 14 is connected with the sample tray 6 and used for sensing the sample temperature in the center of the sample tray.

The controller 10 controls the movement of the lifting device, and the lifting device is moved to the thawing chamber 1 or the freezing chamber 2 through the controller 10 according to the user's needs.

The controller 10 is also connected to a combined injection assembly, and the controller 10 controls the argon/krypton/xenon mixed gas combined injection assembly to inject the mixed gas into the freezing chamber 2 when a freezing operation is performed.

The argon/krypton/xenon mixed gas combined injection assembly is connected with the freezing chamber 2.

The argon/krypton/xenon mixed gas combined injection assembly comprises an argon/krypton/xenon mixed gas injection device 11, a liquid nitrogen injection device 9, an air compressor 8 and a vacuum pump 12.

The argon/krypton/xenon mixed gas injection device 11 is also connected with the thawing chamber 1; the argon/krypton/xenon mixed gas injection device 11 comprises an argon/krypton/xenon mixed gas steel cylinder, a nozzle, a flow control valve and a gas inlet insulating pipe, wherein the argon/krypton/xenon mixed gas steel cylinder is controlled by a solenoid valve, and the argon/krypton/xenon mixed gas injection device 11 is further connected with the thawing chamber 1.

The freezing chamber 2 is provided with a rear fan 7 which is used for stirring the gas in the whole cavity to ensure that the temperature is uniformly distributed; the freezing chamber 2 is also provided with a rear-mounted heat preservation pipe which is connected with the external environment.

The liquid nitrogen injection device 9 comprises a liquid nitrogen dewar tank controlled by an electromagnetic valve, a nozzle, a flow control valve and an air inlet heat preservation pipe.

Example 2

The device in embodiment 1 is applied to a freeze-thawing process of fresh food materials, and the specific method is as follows:

the method comprises the following steps: pretreating food materials: firstly, cleaning, peeling, cutting, blanching and color protecting food materials, then moving the sample tray 6 into the thawing chamber 1, wherein mixed gas transmitted from the freezing chamber 2 through a hose after the last use can be used for quickly cooling and precooling fresh food, and the temperature is controlled to be maintained at 0-4 ℃ by a temperature control device;

placing a fresh food sample in the sample tray 6, evacuating the whole thawing chamber 1 by a vacuum pump 12, introducing argon/krypton/xenon mixed gas with the relative pressure of 0-0.03 MPa into the thawing chamber 1 by the argon/krypton/xenon mixed gas injection device 11 to realize the argon/krypton/xenon micro-pressurization treatment of fresh food materials before freezing, and forming a cage-shaped gas hydrate by the pressurized inert gas argon/krypton/xenon mixed gas and fresh food water molecules; the formation of gas hydrate in the fresh food can reduce the activity of water molecules in tissues and the activity of enzyme molecules to inhibit the metabolic activity of the fresh food, thereby achieving the protection effect in the freezing and thawing process.

Step two: freezing food materials: firstly, the food materials on the sample tray 6 are moved to the freezing chamber 2 by the lifting component 4, the controller 10 starts the combined injection component, so that mixed gas consisting of argon/krypton/xenon mixed gas and liquid nitrogen enters the freezing chamber at a preset flow velocity V1 until a temperature value fed back by the second temperature sensor 14 reaches a preset temperature T1 in the controller 10, and a first-stage cooling process is completed;

secondly, the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas of the argon/krypton/xenon mixed gas combined injection assembly is increased by the controller 10, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor 14 reaches the preset temperature T2 in the controller 10, and the second-stage rapid freezing process of crossing the maximum ice crystal generation zone of the sample is completed;

finally, the controller reduces the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas valve of the argon/krypton/xenon mixed gas combined injection assembly, reduces the flow rate of the mixed gas input into the heat preservation hose to V3, and closes the input of the liquid nitrogen and the argon/krypton/xenon mixed gas when the temperature value fed back by the second temperature sensor meets the material freezing temperature value preset in the controller 10, so that all the materials in the freezing chamber 2 are frozen.

Step three: food material unfreezing: the food materials on the sample tray 6 are moved to the thawing chamber 1 by the lifting assembly 4, the controller 10 controls the input of argon/krypton/xenon mixed gas for precooling, and the thawing of the food materials is accelerated by adopting a method of fast heating of a far infrared irradiation surface and combining an electrostatic field, wherein the used far infrared power is 0-700W/root, the infrared working time is 30-80s, and the intermittent time is 30-60s; the intensity of the used electrostatic field is 0-50kV, the intensity of the electric field acting on the sample is 0-5kV/cm, and the unfreezing treatment of the food materials is accelerated.

Step four: and the residual mixed gas in the freezing chamber 2 enters the thawing chamber 1 again through a hose and is used for precooling food materials during next pretreatment.

Step five: freezing and thawing other food materials: and circularly performing the operations from the first step to the fourth step.

Example 3

The device in example 1 is applied to the freeze-thaw process of Hami melons, and the specific method is as follows:

the method comprises the following steps: pretreating Hami melons: firstly, cleaning, peeling and cutting food materials, placing Hami melons on a sample tray 6, then moving the sample tray 6 into the thawing chamber 1, enabling mixed gas transmitted from the freezing chamber 2 through a hose after the last use to be used for rapid cooling and precooling of the Hami melons, and controlling the temperature to be maintained at 4 ℃ by a temperature control device;

placing Hami melon samples in the sample tray 6, evacuating the whole thawing chamber 1 by a vacuum pump 12, introducing argon/krypton/xenon mixed gas with relative pressure of 0.03MPa into the thawing chamber 1 by the argon/krypton/xenon mixed gas injection device 11, and keeping for 20min under the conditions of temperature of 4 ℃, relative humidity of 85% and relative pressure of 0.03MPa of argon/krypton/xenon mixed gas.

Step two: freezing food materials: firstly, the Hami melons on the sample tray 6 are moved to the freezing chamber 2 by the lifting assembly 4, the controller 10 starts the combined injection assembly, so that mixed gas consisting of argon/krypton/xenon mixed gas and liquid nitrogen enters the freezing chamber at a preset flow rate V1 until a temperature value fed back by the second temperature sensor 14 reaches a preset temperature T1 in the controller 10, and a first-stage temperature reduction process is completed;

secondly, the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas of the argon/krypton/xenon mixed gas combined injection assembly is increased by the controller 10, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor 14 reaches the preset temperature T2 in the controller 10, and the second-stage rapid freezing process of crossing the maximum ice crystal generation zone of the sample is completed;

finally, the controller reduces the input amount of the liquid nitrogen and argon/krypton/xenon mixed gas valve of the argon/krypton/xenon mixed gas combined injection assembly, and reduces the flow rate of the mixed gas input into the heat preservation hose to V3, and when the temperature value fed back by the second temperature sensor meets the preset material freezing temperature value in the controller 10, the liquid nitrogen and argon/krypton/xenon mixed gas input is closed, and all the materials in the freezing chamber 2 are frozen.

Step three: food material unfreezing: the food materials on the sample tray 6 are moved to the thawing chamber 1 by the lifting assembly 4, the controller 10 controls the input of argon/krypton/xenon mixed gas for precooling, and the thawing of the food materials is accelerated by adopting a method of fast heating of a far infrared irradiation surface and combining an electrostatic field, wherein the used far infrared power is 300W multiplied by 4, the infrared working time is 70s, and the intermittent time is 60s; the intensity of the used electrostatic field is 50kV/cm, and the intensity of the electric field acting on the Hami melon is 5kV/cm; the far infrared surface irradiation and the electrostatic field treatment can simultaneously act on the inside and the outside of the Hami melon sample, and the unfreezing process is accelerated.

Step four: and the residual mixed gas in the freezing chamber 2 enters the thawing chamber 1 again through a hose and is used for precooling food materials during next pretreatment.

Example 4

The apparatus of example 1 was applied to the freeze-thaw process of broccoli, and the specific method was as follows:

the method comprises the following steps: pretreating Hami melons: firstly, cleaning, cutting and blanching food materials (selecting fresh broccoli without mechanical damage and diseases and insect pests, cleaning, cutting inflorescences with uniform sizes, then blanching in hot water of 95 ℃ for 1min, then cooling in cold water, fishing out and draining water), placing the broccoli in a sample tray 6, then moving the sample tray 6 to the thawing chamber 1, wherein mixed gas transmitted from the freezing chamber 2 through a hose after the previous use can be used for quickly cooling and precooling the broccoli, and the temperature is controlled by a temperature control device to be maintained at 4 ℃;

placing a broccoli sample in the sample tray 6, evacuating the whole thawing chamber 1 by a vacuum pump 12, introducing argon/krypton/xenon mixed gas with the relative pressure of 0.02MPa into the thawing chamber 1 by the argon/krypton/xenon mixed gas injection device 11, and keeping the temperature at 4 ℃, the relative humidity at 90% and the relative pressure of the argon/krypton/xenon mixed gas at 0.02MPa for 20min.

Step two: freezing food materials: firstly, the broccoli on the sample tray 6 is moved to the freezing chamber 2 by the lifting assembly 4, the controller 10 starts the combined injection assembly, so that the mixed gas composed of the argon/krypton/xenon mixed gas and the liquid nitrogen enters the freezing chamber at a preset flow rate V1 until the temperature value fed back by the second temperature sensor 14 reaches a preset temperature T1 in the controller 10, and the first-stage temperature reduction process is completed;

secondly, the controller 10 increases the input amount of liquid nitrogen and the input amount of the argon/krypton/xenon mixed gas combined injection assembly, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor 14 reaches the preset temperature T2 in the controller 10, and the second-stage quick freezing process of passing through the maximum ice crystal generation zone of the sample is completed;

finally, the controller reduces the input amount of the liquid nitrogen and argon/krypton/xenon mixed gas valve of the argon/krypton/xenon mixed gas combined injection assembly, and reduces the flow rate of the mixed gas input into the heat preservation hose to V3, and when the temperature value fed back by the second temperature sensor meets the preset material freezing temperature value in the controller 10, the liquid nitrogen and argon/krypton/xenon mixed gas input is closed, and all the materials in the freezing chamber 2 are frozen.

Step three: food material unfreezing: the food materials on the sample tray 6 are moved to the thawing chamber 1 by the lifting assembly 4, the controller 10 controls the input of argon/krypton/xenon mixed gas for precooling, and the thawing of the food materials is accelerated by adopting a method of fast heating of a far infrared irradiation surface and combining an electrostatic field, wherein the used far infrared power is 250 Wx 4, the infrared working time is 60s, and the intermittent time is 60s; the intensity of the used electrostatic field is 30kV, and the intensity of the electric field acting on the sample is 3kV/cm; the far infrared surface irradiation and the electrostatic field treatment can simultaneously act on the inside and the outside of the broccoli sample, and the unfreezing process is accelerated.

Step four: and the residual mixed gas in the freezing chamber 2 enters the thawing chamber 1 again through a hose and is used for precooling food materials during next pretreatment.

Example 5

The device in example 1 is applied to the freeze-thaw process of yellow peaches, and the specific method is as follows:

the method comprises the following steps: pre-treating yellow peaches: screening and cleaning raw materials: selecting yellow peaches with uniform size, moderate maturity and no mechanical injury, and cleaning; peeling: peeling and denucleating the cleaned yellow peaches by using a peeling machine; cutting: the yellow peaches after being cleaned and denucleated are cut into blocks; color protection: the yellow peaches after being cut into blocks are soaked in a color protection liquid for 2 hours, and the color protection liquid consists of 0.1 to 0.5 percent (w/v) of sodium erythorbate, 0.1 to 0.5 percent (w/v) of citric acid and 0.5 to 1 percent (w/v) of sodium chloride. Then fishing out and draining off water.

Placing the yellow peaches on a sample tray 6, then moving the sample tray 6 into the thawing chamber 1, wherein mixed gas transmitted from the freezing chamber 2 through a hose after the previous use can be used for rapid cooling and precooling of the yellow peaches, and the temperature is maintained at 4 ℃ under the regulation and control of a temperature control device;

placing the yellow peach sample in the sample tray 6, evacuating the whole thawing chamber 1 by a vacuum pump 12, introducing an argon/krypton/xenon mixed gas with a relative pressure of 0.03MPa into the thawing chamber 1 by the argon/krypton/xenon mixed gas injection device 11, and keeping the temperature at 4 ℃, the relative humidity at 80% and the relative pressure of the argon/krypton/xenon mixed gas at 0.03MPa for 20min.

Step two: freezing food materials: firstly, the yellow peaches on the sample tray 6 are moved to the freezing chamber 2 by the lifting assembly 4, the controller 10 starts the combined injection assembly, so that the mixed gas consisting of the argon/krypton/xenon mixed gas and the liquid nitrogen enters the freezing chamber at a preset flow rate V1 until the temperature value fed back by the second temperature sensor 14 reaches a preset temperature T1 in the controller 10, and the first-stage temperature reduction process is completed;

secondly, the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas of the argon/krypton/xenon mixed gas combined injection assembly is increased by the controller 10, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor 14 reaches the preset temperature T2 in the controller 10, and the second-stage rapid freezing process of crossing the maximum ice crystal generation zone of the sample is completed;

finally, the controller reduces the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas valve of the argon/krypton/xenon mixed gas combined injection assembly, reduces the flow rate of the mixed gas input into the heat preservation hose to V3, and closes the input of the liquid nitrogen and the argon/krypton/xenon mixed gas when the temperature value fed back by the second temperature sensor meets the material freezing temperature value preset in the controller 10, so that all the materials in the freezing chamber 2 are frozen.

Step three: food material unfreezing: the food materials on the sample tray 6 are moved to the unfreezing chamber 1 by the lifting assembly 4, the controller 10 controls the input argon/krypton/xenon mixed gas to be precooled, the far infrared irradiation surface is adopted for rapid heating, and the unfreezing of the food materials is accelerated by combining the method of an electrostatic field, wherein the used far infrared power is 300W multiplied by 4, the infrared working time is 70s, and the intermittent time is 60s; the intensity of the used electrostatic field is 50kV, and the intensity of the electric field acting on the sample is 5kV/cm; the far infrared surface irradiation and the electrostatic field treatment can simultaneously act on the inside and the outside of the yellow peach sample, and the unfreezing process is accelerated.

Step four: and the residual mixed gas in the freezing chamber 2 enters the thawing chamber 1 again through a hose and is used for precooling food materials during next pretreatment.

Example 6

The device of example 1 was applied to a beef freeze-thaw process, the specific method being as follows:

the method comprises the following steps: pretreating beef: taking fresh beef legs, removing irregular parts and redundant fat and connective tissues, and then cutting into square blocks with uniform size, wherein the weight of each block is about 125 g;

the temperature is 4 ℃, the controller starts mixed gas tail gas to flow into the unfreezing chamber to realize rapid precooling of the materials, the controller opens the vacuum pump to evacuate for 1min and then closes the vacuum pump, and opens the argon/krypton/xenon mixed gas valve to enable the cavity to be filled with the argon/krypton/xenon mixed gas and to be pressurized to 0.02Mpa; the temperature is kept for 20min at 4 ℃, the relative humidity is 85 percent, and the relative pressure of the argon/krypton/xenon mixed gas is 0.02 MPa.

Step two: freezing food materials: firstly, the beef on the sample tray 6 is moved to the freezing chamber 2 by the lifting assembly 4, the controller 10 starts the argon/krypton/xenon mixed gas combined injection assembly, so that the mixed gas consisting of the argon/krypton/xenon mixed gas and the liquid nitrogen enters the freezing chamber at a preset flow rate V1 until the temperature value fed back by the second temperature sensor 14 reaches a preset temperature T1 in the controller 10, and the first-stage temperature reduction process is completed;

secondly, the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas of the argon/krypton/xenon mixed gas combined injection assembly is increased by the controller 10, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor 14 reaches the preset temperature T2 in the controller 10, and the second-stage rapid freezing process of crossing the maximum ice crystal generation zone of the sample is completed;

finally, the controller reduces the input amount of the liquid nitrogen and argon/krypton/xenon mixed gas valve of the argon/krypton/xenon mixed gas combined injection assembly, and reduces the flow rate of the mixed gas input into the heat preservation hose to V3, and when the temperature value fed back by the second temperature sensor meets the preset material freezing temperature value in the controller 10, the liquid nitrogen and argon/krypton/xenon mixed gas input is closed, and all the materials in the freezing chamber 2 are frozen.

Step three: food material unfreezing: the food materials on the sample tray 6 are moved to the thawing chamber 1 by the lifting assembly 4, the controller 10 controls the input of argon/krypton/xenon mixed gas for precooling, the food materials are rapidly thawed by adopting a method of rapidly heating the far infrared irradiation surface and combining with an electrostatic field, the far infrared irradiation surface is rapidly heated and combined with the electrostatic field under the protection of the argon/krypton/xenon mixed gas, the far infrared power is 300W multiplied by 4, the infrared working time is 80s, and the intermittent time is 50s; the intensity of the used electrostatic field is 30kV, and the intensity of the electric field acting on the sample is 3kV/cm; the far infrared surface irradiation and the electrostatic field treatment can simultaneously act on the inside and the outside of the beef sample, the thawing process is accelerated, the temperature of a thawing chamber is adjusted to 4 ℃, and when the central temperature of the sample is reduced to 0 ℃, the thawing is finished.

Step four: and the residual mixed gas in the freezing chamber 2 enters the thawing chamber 1 again through a hose and is used for precooling food materials during next pretreatment.

Example 7

The device of example 1 was applied to the freeze-thaw process of fish meat in the following specific method:

the method comprises the following steps: selecting a single fresh hairtail with the weight of about 1kg as a test material. Removing head, tail and viscera, and cutting into sections with uniform width in the middle, wherein each section is 10cm in length;

the temperature is 4 ℃, the controller starts mixed gas tail gas to flow into the unfreezing chamber to realize rapid precooling of the materials, the controller opens the vacuum pump to evacuate for 1min and then closes the vacuum pump, and opens the argon/krypton/xenon mixed gas valve to enable the cavity to be filled with the argon/krypton/xenon mixed gas and to be pressurized to 0.02Mpa; the temperature is kept for 20min at 4 ℃, the relative humidity is 85 percent, and the relative pressure of the argon/krypton/xenon mixed gas is 0.02 MPa.

Step two: freezing food materials: firstly, the fish meat on the sample tray 6 is moved to the freezing chamber 2 by the lifting assembly 4, the controller 10 starts the argon/krypton/xenon mixed gas combined injection assembly, so that mixed gas consisting of the argon/krypton/xenon mixed gas and liquid nitrogen enters the freezing chamber at a preset flow rate V1 until a temperature value fed back by the second temperature sensor 14 reaches a preset temperature T1 in the controller 10, and a first-stage temperature reduction process is completed;

secondly, the controller 10 increases the input amount of liquid nitrogen and the input amount of the argon/krypton/xenon mixed gas combined injection assembly, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor 14 reaches the preset temperature T2 in the controller 10, and the second-stage quick freezing process of passing through the maximum ice crystal generation zone of the sample is completed;

finally, the controller reduces the input quantity of the liquid nitrogen and the argon/krypton/xenon mixed gas valve of the argon/krypton/xenon mixed gas combined injection assembly, reduces the flow rate of the mixed gas input into the heat preservation hose to V3, and closes the input of the liquid nitrogen and the argon/krypton/xenon mixed gas when the temperature value fed back by the second temperature sensor meets the material freezing temperature value preset in the controller 10, so that all the materials in the freezing chamber 2 are frozen.

Step three: food material unfreezing: the food materials on the sample tray 6 are moved to the thawing chamber 1 by the lifting assembly 4, the controller 10 controls the input of argon/krypton/xenon mixed gas for precooling, the food materials are rapidly thawed by adopting a method of rapidly heating the far infrared irradiation surface and combining with an electrostatic field, the far infrared irradiation surface is rapidly heated and combined with the electrostatic field under the protection of the argon/krypton/xenon mixed gas, the far infrared power is 300W multiplied by 4, the infrared working time is 60s, and the intermittent time is 60s; the intensity of the used electrostatic field is 30kV, and the intensity of the electric field acting on the sample is 3kV/cm; the far infrared surface irradiation and the electrostatic field treatment can simultaneously act on the inside and the outside of the beef sample, the thawing process is accelerated, the temperature of a thawing chamber is adjusted to 4 ℃, and when the central temperature of the sample is reduced to 0 ℃, the thawing is finished.

Step four: and the residual mixed gas in the freezing chamber 2 enters the thawing chamber 1 again through a hose and is used for precooling food materials during next pretreatment.

Comparative example

Two additional control groups of the foodstuffs used in examples 3, 4, 5, 6 and 7 were set up and compared with the method of the invention:

control group (1): quickly freezing by adopting a forced air quick-freezing cabinet at the temperature of-40 ℃, and naturally thawing by adopting a cold air cabinet at the temperature of 4 ℃;

control group (2): quick-freezing with liquefied nitrogen, and naturally thawing in a cold air cabinet at 4 deg.C;

the sample treatment method and the freeze/thaw temperature range were the same as in examples 3, 4, 5, 6, and 7.

Referring to table 1, the freeze-thaw integrated machine of the invention can significantly reduce the freezing time (0 to-5 ℃) and the freezing time (4 to-18 ℃) of five fresh foods, and has significant difference. Wherein the freezing time (0 to-5 ℃) is the time for the product to pass through the maximum ice crystal generation zone when being frozen, and the shorter time leads to the generation of finer ice crystals, thereby being beneficial to maintaining the quality of the frozen fresh food. The freeze thawing integrated machine can obviously shorten the thawing time (-18-0 ℃) of five fresh foods, and has obvious difference. Fresh food juice loss after freezing and thawing by the freezing and thawing integrated machine is less, and hardness is better maintained.

TABLE 1 influence of different freezing and thawing modes on the freezing and thawing characteristics of five fresh foods

The difference of the lower case letters behind the same number represents obvious difference (P < 0.05)

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. An integrated circulating freeze thawing device is characterized by comprising a freezing chamber, a thawing chamber, a lifting assembly, a temperature acquisition device, a controller and an argon/krypton/xenon mixed gas combined injection assembly;

the freezing chamber and the thawing chamber are vertically distributed and connected by a hose;

the lifting assembly is arranged between the thawing chamber and the freezing chamber and can move freely, the lifting assembly consists of a lifting device and a sample tray, and the sample tray is connected with the lifting device through a sample tray frame;

the controller is connected with the temperature acquisition device and the combined injection assembly;

the combined injection assembly is connected with the freezing chamber, and the argon/krypton/xenon mixed gas combined injection assembly comprises an argon/krypton/xenon mixed gas injection device, a liquid nitrogen injection device, an argon/krypton/xenon mixed gas dynamic proportion adjusting device, an air compressor, a pressure relief valve and a vacuum pump; the argon/krypton/xenon mixed gas injection device is also connected with the thawing chamber;

the thawing chamber comprises a far infrared generating device, an electrostatic field device and a temperature control device.

2. The integrated circulating freezing and thawing apparatus according to claim 1, wherein said sample tray is a net structure made of PTFE.

3. The integrated circulating freeze thawing apparatus of claim 1, wherein the sample tray rack material is polytetrafluoroethylene.

4. The integrated circulating freeze-thawing apparatus according to claim 1, wherein the temperature acquisition device is connected with the lifting assembly, the temperature acquisition device comprises a first temperature sensor and a second temperature sensor, the first temperature sensor is suspended, the second temperature sensor is connected with the sample tray, and the second temperature sensor comprises a 12-way food insertion type temperature sensor and a 2.5mm silver-plated waterproof shielding wire.

5. The integrated circulating freeze-thawing apparatus according to claim 1, wherein the argon/krypton/xenon mixed gas injection device and the liquid nitrogen injection device are provided with a nozzle, a flow control valve and an air inlet insulating pipe.

6. The integrated circulating freeze-thawing apparatus according to claim 1, wherein the freezing chamber is provided with a rear fan and a rear heat preservation pipe, and the rear heat preservation pipe is connected with the external environment.

7. The integrated circulating freeze-thawing apparatus according to claim 1, wherein the far infrared generator comprises 4 far infrared tubes, which are laid on two sides of the inner wall of the thawing chamber, and the electrostatic field device is a barbed electrode plate.

8. The integrated circulating freeze-thawing apparatus according to claim 1, wherein the far infrared generator and the electrostatic field device are provided with shielding and protecting devices.

9. The integrated circulating freeze thawing apparatus of claim 1, wherein said temperature control means comprises a heating plate and a refrigeration compressor, said temperature control means also being connected to said controller.

10. The use of an integrated circulating freeze thawing apparatus according to claim 1 in high quality freeze thawing of fresh food, comprising the steps of:

the method comprises the following steps: pretreating food materials under micro-pressure: firstly, cleaning, peeling, cutting, blanching and protecting color of food materials, then moving the sample tray into the thawing chamber, placing a sample on the sample tray, vacuumizing the whole thawing chamber by using a vacuum pump, and introducing argon/krypton/xenon mixed gas with the relative pressure of 0-0.03 MPa into the thawing chamber by using the mixed gas injection device to realize the argon/krypton/xenon micro-pressurization treatment of fresh food materials before freezing;

step two: dynamically quick-freezing food materials by mixed gas: firstly, the food materials on the sample tray are moved to the freezing chamber by the lifting assembly, the controller starts the combined injection assembly, so that mixed gas consisting of argon/krypton/xenon mixed gas and liquid nitrogen enters the freezing chamber at a preset flow rate V1 until a temperature value fed back by the second temperature sensor reaches a preset temperature T1 in the controller, and a first-stage cooling process is completed; secondly, the input quantity of the liquid nitrogen and argon/krypton/xenon mixed gas of the combined injection assembly is increased by the controller, the speed of the input mixed gas is increased to V2, the temperature value fed back by the second temperature sensor reaches the preset temperature T2 in the controller, and the quick freezing process of the maximum ice crystal generation zone of the crossing sample is finished; finally, the controller reduces the input quantity of the liquid nitrogen and argon/krypton/xenon mixed gas valve of the combined injection assembly, reduces the flow speed of the mixed gas input into the heat-preservation hose to V3, and closes the input of the liquid nitrogen and argon/krypton/xenon mixed gas when the temperature value fed back by the second temperature sensor meets the preset material freezing temperature value in the controller, so that all the materials in the freezing chamber are frozen;

step three: argon/krypton/xenon protected thawed food material: the food materials on the sample tray are moved to the unfreezing chamber by the lifting assembly, the controller controls input of argon/krypton/xenon mixed gas to carry out precooling and protection, and the food materials are quickly unfrozen by adopting a method of quickly heating a far infrared irradiation surface and combining an electrostatic field.

Step four: and the residual mixed gas in the freezing chamber enters the unfreezing chamber through a hose and is used for precooling food materials during next pretreatment.

Step five: freezing and thawing other food materials: and circularly performing the operations from the first step to the fourth step.

Images