CN116569955A

CN116569955A - Thawing method for frozen food

Info

Publication number: CN116569955A
Application number: CN202310626086.8A
Authority: CN
Inventors: 杨哪; 姚黄兵; 周宇益; 徐学明; 潘思邈; 张孝; 黄文哲; 巫宇航; 韦利稳; 陈思蕊
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2023-04-03
Filing date: 2023-05-30
Publication date: 2023-08-11
Also published as: CN116616333A; CN116530557A; CN116530556A

Abstract

The invention discloses a thawing method of frozen food. The thawing method comprises m thawing stages, each thawing stage comprises n thawing periods, each thawing period comprises the step of sequentially applying oscillating current to x parts of frozen food, wherein the heat generated by the oscillating current in the frozen food is the same as or slightly greater than the energy required by ice crystals in the frozen food to be converted into liquid water, so that the frozen food is thawed, the thawing end temperature of the inner area of the frozen food is not more than 15 ℃, and m, n is more than or equal to 1, x is more than or equal to 1, m, n and x are integers. According to the method provided by the invention, the specific oscillating current is applied to the frozen food in stages, so that ice crystals in the frozen food are gradually melted, the frozen food is thawed, and the thawed food has higher quality.

Description

Thawing method for frozen food

Technical Field

The invention particularly relates to a thawing method for frozen food, and belongs to the technical field of food thawing.

Background

As the population grows, there is an increasing global demand for food. The freezing treatment can prolong the quality guarantee period of the food by inhibiting the growth of microorganisms and the activity of enzymes in the food without adopting an exogenous preservative. In addition, the food materials can be frozen and preserved according to seasonality and regional food materials, so that the time and space obstruction can be broken, and the global circulation of the food materials can be realized. However, frozen foods require thawing before eating or reprocessing, and improper processing can lead to bacterial growth, compromising the flavor and nutritional value of the food.

At present, common thawing methods comprise natural thawing and cold water dipping thawing, and the traditional method does not need special equipment, but has long time consumption and is easy to cause the problems of microorganism breeding and the like. In recent years, the emerging thawing technologies include microwave thawing, superheated steam and oven thermal thawing, ultrasonic thawing and radio frequency thawing, which have high thawing speed, but for foods in different forms and different states, uneven thawing, protein molecule denaturation or degradation are easily caused.

Specific oscillating current is adopted for irregular frozen food, the specific oscillating current comprises frequency, intensity and period, water molecules, macromolecular substances, ions and the like in the frozen food can be caused to generate oscillating friction and cause internal ice crystal ablation, and the critical energy can convert the internal ice crystal of the frozen food into liquid water, so that the food can be uniformly thawed. Compared with constant thawing or simultaneous thawing treatment by stages of oscillating current, each region periodically generates specific oscillating current signals by stages, which is beneficial to inhibiting secondary crystallization of ice crystals during thawing, reducing damage to cell tissues and juice phenomenon, improving thawing quality of products, maintaining surface color and luster, and preventing phenomena of overhigh short-time aggregation energy and local overheating of the surface during thawing. The periodic thawing in stages can periodically apply specific oscillating current signals to frozen foods with different thicknesses and shapes, and the scanning type cyclic application treatment promotes the specific area to uniformly receive energy, improves the pretreatment efficiency of the frozen foods and reduces the loss. The specific oscillating current staged periodic thawing treatment mode is adopted, and a safe and environment-friendly new method is provided for rapid adjustment of frozen foods.

Disclosure of Invention

The main object of the present invention is to provide a method for thawing frozen food, which overcomes the drawbacks of the prior art.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention comprises the following steps:

the invention provides a thawing method of frozen food, which comprises m thawing stages, wherein each thawing stage comprises n thawing periods, each thawing period comprises the step of sequentially applying oscillating current to x parts of the frozen food, wherein the heat generated by the oscillating current in the frozen food is the same as or slightly greater than the energy required by the ice crystals in the frozen food to be converted into liquid water, so that the frozen food is thawed, and the thawing end point temperature of the inner area of the frozen food is not more than 15 ℃, wherein m, n, x is more than or equal to 1, m, n and x are integers.

Compared with the prior art, the invention has the advantages that:

according to the thawing method of frozen food, specific oscillating current is applied to each part in a staged and periodic manner, and different parts of frozen food can intermittently receive energy under the scanning treatment flow, namely, the rapid application of a horse race lamp is facilitated, and uniform ablation of ice crystals in the frozen food is facilitated;

Compared with the constant thawing of oscillating current, the thawing method of frozen food provided by the invention can further prevent the phenomena of overhigh short-time aggregation energy and local overheating of the surface, and the juice loss of the frozen food is less;

compared with the method of thawing simultaneously in stages, the frozen food thawing method provided by the invention has better ice crystal ablating linearity degree of the frozen food, so that the temperature difference of the area of the inner section of the frozen food at the end point of thawing is smaller, and the quality of the thawed food is higher.

Drawings

FIG. 1 is a schematic view of a non-thermal thawing apparatus according to embodiment 1 of the present invention;

FIG. 2 is a schematic diagram showing the structure of an oscillating current emitting device comprising a plurality of electrodes in embodiment 2 of the present invention;

fig. 3 is a schematic view showing the structure of a non-thermal thawing apparatus for thawing frozen foods according to embodiment 3 of the present invention;

FIG. 4 is a schematic diagram showing the structure of an oscillating current emitting device comprising a plurality of electrodes in embodiment 3 of the present invention;

fig. 5 is a schematic view showing the structure of a non-thermal thawing apparatus for thawing frozen foods according to example 4 of the present invention;

FIG. 6 is a schematic diagram showing the structure of an oscillating current emitting device comprising a plurality of electrodes in embodiment 4 of the present invention;

Fig. 7 is a schematic structural view of an oscillating current emitting element comprising a plurality of electrodes in embodiment 5 of the present invention;

fig. 8 is a schematic structural view of an oscillating current emitting element comprising a plurality of electrodes in embodiment 6 of the present invention;

fig. 9 is a schematic structural view of an oscillating current emitting element comprising a plurality of electrodes in embodiment 7 of the present invention;

fig. 10 is a schematic structural view of an oscillating current emitting element comprising a plurality of electrodes in embodiment 8 of the present invention.

Detailed Description

In view of the shortcomings in the prior art, the inventor of the present invention has long studied and practiced in a large number of ways to propose the technical scheme of the present invention. The technical scheme, the implementation process, the principle and the like are further explained as follows.

Noun interpretation in the present invention:

frozen food: a food product frozen at a temperature below-18 ℃.

Non-thermal thawing: the food is not heated and thawed by heat transfer, and the inside of the food is thawed under the condition of no external heat source.

Further, each of the thawing periods includes: y oscillating currents are applied to one or more portions of the frozen food product at a time, y being greater than or equal to 1, y being an integer.

Further, the oscillating current is periodically applied to one portion of the frozen food product at a time during each thawing cycle, and the period of application of the oscillating current is 0-10min.

Further, the thickness of the x portions of the frozen food product is the same or different, and the current intensity of the oscillating current applied to the x portions of the frozen food product is positively correlated with the thickness of each portion of the frozen food product.

Further, the thickness of the frozen food is within 15cm, the current intensity of each oscillating current is 3-2000mA, the current frequency is 1Hz-100kHz, and the current intensity is an effective value.

Further, the current waveform of the oscillating current is a square wave or a sawtooth wave.

Further, the thickness of the selected portion of the frozen food product corresponds to a current intensity of the oscillating current applied to the selected portion of 0.5-15cm:3-2000mA.

Further, when the thickness of the selected portion of the frozen food is 0.5-8cm, the current intensity of the oscillating current applied to the selected portion is 3-400mA; when the thickness of the selected portion of the frozen food product is 8-15cm, the current intensity of the oscillating current applied to the selected portion is 400-2000mA.

Further, the thawing method comprises the following steps: the gradient of the oscillating current applied to the same portion of the frozen food in the m thawing phases is reduced, and the holding time of the oscillating current applied to the same portion of the frozen food in the m thawing phases is kept the same, or the gradient of the oscillating current applied to the same portion of the frozen food in the m thawing phases is kept the same, and the holding time gradient of the oscillating current applied to the same portion of the frozen food in the m thawing phases is reduced.

Further, the time of each thawing period is 0.1-10min, and the holding time of the oscillating current applied to x portions of the frozen food product is the same for each thawing period.

Further, for the same closed loop, the current intensity of the oscillating current applied in the mth thawing stage is 20-80% of the current intensity of the oscillating current applied in the mth-1 thawing stage, or for the same closed loop, the holding time of the oscillating current applied in the mth thawing stage is 20-80% of the holding time of the oscillating current applied in the mth-1 thawing stage, and (m-1) is not less than 1.

Specifically, when the conductive frozen food is contacted with two conductive modules electrically connected with a control power supply, current can pass through the food and release energy, so that self-heating phenomenon of the food is caused, and the thawing effect is achieved.

Specifically, compared with constant thawing of oscillation current or simultaneous thawing of phases, specific oscillation current is applied to each part in phases and periodicity, under the scanning treatment process, different parts of frozen food can intermittently receive energy, namely the rapid application of a horse race lamp type is realized, and uniform ablation of ice crystals in the frozen food is facilitated; compared with constant thawing of oscillating current, the invention can further prevent the phenomena of overhigh short-time aggregation energy and local overheating of the surface, and the juice loss of frozen food is less; compared with the staged simultaneous thawing, the frozen food of the invention has better ice crystal ablation linearity, so the temperature difference of the area of the inner section of the frozen food at the thawing end point is smaller.

In a more specific embodiment, the thawing method specifically includes: and applying the oscillating current into the closed loop by the control power supply in sequence, wherein the group of conductive modules comprises two conductive modules which are respectively and electrically connected with two different terminals of the control power supply.

Further, the thawing treatment specifically includes: and sequentially applying a plurality of oscillating currents into a plurality of closed loops by the control power supply, wherein each part of the frozen food corresponds to at least one closed loop.

Further, each conductive module includes one or more conductive structures, and a plurality of conductive structures included in each conductive module are connected in series and/or in parallel.

Further, a plurality of conductive structures included in each conductive module are arranged at intervals, and a distance between two adjacent conductive structures is 1-30mm.

Further, the thawing method further comprises the following steps: the current intensity of the oscillating current applied to each portion of frozen food product is kept constant during each thawing cycle.

Further, the thawing method specifically includes: monitoring the oscillating current in the closed loop corresponding to the selected part by using ohm law and adopting an oscillating voltage, and adjusting the current intensity applied to the corresponding closed loop according to the duty ratio of the oscillating voltage in the closed loop so as to keep the current intensity of the oscillating current in the closed loop constant, wherein the effective value of the oscillating voltage is 20-300V, and the duty ratio is 1-99%; the thickness of the frozen food product is positively correlated with the self-impedance, that is, the greater the thickness, the greater the impedance corresponding to the portion.

Further, the thawing method specifically includes: after each thawing phase is completed, the impedance in the closed loop is measured and the current intensity of the oscillating current in the closed loop is adjusted according to the impedance.

Further, the thawing end temperature of the inner region of the frozen food is-4-15 ℃.

Further, the frozen food includes frozen aquatic products, frozen meat products or frozen flour products, the frozen meat products include frozen livestock products or frozen poultry products, and the like.

Aiming at a plurality of defects in the prior art, the inventor of the present invention can put forward the technical proposal of the invention through long-term research and a large number of practices. The technical scheme, implementation process and principle and the like will be further explained with reference to the attached drawings and specific embodiments. It should be understood, however, that within the scope of the present invention, the above-described technical features of the present invention and technical features specifically described in the following (embodiments) may be combined with each other to constitute new or preferred technical solutions. And are limited to a space, and are not described in detail herein.

Example 1

Referring to fig. 1, a non-thermal thawing apparatus may be provided in or as a part of an electric appliance having a thawing function, which may be a refrigerator, a microwave oven, a thawing box, an electric oven, etc., and specifically, may be a small-sized home electric appliance, a large-sized industrial electric appliance, etc. The non-thermal thawing device may be disposed in a thawing space (thawing layer) of an electric appliance having a thawing function, and a circuit connection structure between the non-thermal thawing device and the electric appliance having a thawing function is known to those skilled in the art, and is not particularly limited herein.

The non-thermal thawing device comprises two oscillating current emitting assemblies 10 and a control power supply 20, wherein the two oscillating current emitting assemblies 10 are opposite and are arranged at intervals, a containing space for containing frozen food 30 is formed between the two oscillating current emitting assemblies 10, the control power supply 20 is electrically connected with the two oscillating current emitting assemblies 10, and provides oscillating current with current intensity of 3-2000mA, current frequency of 1Hz-100kHz and current waveform of square wave for the two oscillating current emitting assemblies 10, and the oscillating current generates heat in frozen food which is positioned in the containing space and is contacted with the two oscillating current emitting assemblies 10, and the energy required by the ice crystal in the frozen food is the same as or slightly larger than the energy required by the ice crystal in the frozen food to be converted into liquid water, so that the frozen food is thawed, and the thawing end point temperature of the frozen food is not more than 15 ℃, namely the non-thermal thawing of the frozen food is realized.

Specifically, the two oscillating current emitting assemblies 10 are electrically connected to two terminals of the control power supply 20, respectively, and when the two oscillating current emitting assemblies 10 are electrically connected, one or more closed loops are formed between the two oscillating current emitting assemblies 10 and the control power supply 20, the control power supply 20 can apply a voltage to each closed loop to form the aforementioned oscillating current in each closed loop, and the control power supply can monitor and analyze the thawing state (based on ohm's law) of frozen food between a group of conductive modules (i.e., corresponding to a closed loop) through the applied voltage signal and the current outputted in real time, and adjust the voltage applied to the closed loop according to the impedance in each closed loop.

In this embodiment, the two oscillating-current emitting assemblies 10 may have the same structure, and taking one of the oscillating-current emitting assemblies as an example, the oscillating-current emitting assembly 10 includes one or more conductive modules, the plurality of conductive modules are electrically connected to the control power supply 20, two conductive modules electrically connected to different terminals of the control power supply 20 may cooperate to form a closed loop, and specifically, the control power supply 20 may individually control each or more conductive modules, so that each conductive module may apply an oscillating current with an effective current intensity of 3-2000mA, a current frequency of 1Hz-100kHz, and a current waveform of square wave.

In this embodiment, the working ends of the plurality of conductive modules are matched to form the outline shape of the working surface and can be adjusted to adapt to various forms of unfreezed foods, wherein the working ends of the conductive modules are the ends of the conductive modules facing the accommodating space and contacting the frozen foods.

In this embodiment, the plurality of conductive modules included in each oscillating current emitting assembly 10 may be arranged in series and/or parallel.

In this embodiment, each conductive module may include one or more conductive structures 12, where each conductive module includes a plurality of conductive structures 12 connected in series and/or parallel, and a space between two adjacent conductive structures 12 in each conductive module is 1-30mm.

In this embodiment, the conductive structure 12 may be a conductive contact or a pole head, etc., the conductive structure 12 may also be referred to as an electrode, the shape of a radial cross section of the conductive structure 12 may be a circle, a triangle, a rounded rectangle, a trapezoid, etc., the conductive structure 12 shown in fig. 1 is a spherical structure, and the conductive structure 12 shown in fig. 2 is a rounded cuboid or a cylinder.

In this embodiment, the conductive structure 12 may be made of any one metal or an alloy of two or more metals such as titanium, iron, copper, and aluminum.

Specifically, the oscillating current emission assembly 10 may further include a supporting body 11, where the conductive module may be fixedly disposed on the supporting body 11, but the conductive module itself is of a retractable structure, and the conductive module itself includes a third driving mechanism, where the third driving mechanism is in driving connection with the movable portion of the conductive module and drives the movable portion of the conductive module to move along the axial direction of the conductive module itself, so that working ends of the conductive modules cooperate to form multiple working surfaces with multiple contour shapes; the third driving mechanism can be a linear driving motor or an air cylinder;

or, the conductive modules are movably arranged on the supporting body 11, and the supporting body 11 is also provided with a first driving mechanism which is in transmission connection with the conductive modules and drives the conductive modules to move integrally along the axial direction of the conductive modules, so that the working ends of the conductive modules are matched to form a plurality of working surfaces with various shapes, and the first driving mechanism can be a linear driving motor or a cylinder and the like;

Or, the conductive module is movably disposed on the supporting body 11, and an elastic body is further disposed between the conductive module and the supporting body 11, and the conductive module and the supporting body 11 are respectively connected with the elastic body, so that when the conductive module contacts with frozen food to generate pressure, the elastic body can be deformed in a restorable manner, thereby enabling the conductive module to move along the axial direction thereof under the action of the resultant force of the pressure and the elastic force of the elastic body, so that the working ends of the plurality of conductive modules are matched to form a plurality of working surfaces with various shapes, and the elastic body can be a food-grade silica gel elastic member, a rubber elastic member, a plastic elastic member or a metal elastic member (such as a spring) and the like.

It will be appreciated that the mating connection relationship of the conductive module to the support may be equivalent to the mating connection relationship of some or all of the conductive structures 12 to the support.

In this embodiment, the supporting body 11 may be a conductive or non-conductive member, when the supporting body 11 is a conductive member, the conductive module may be integrally disposed with the supporting body 11, and illustratively, the material of the supporting body 11 may be any one metal of titanium, iron, copper, aluminum or an alloy formed by two or more metals, or may be a non-metal, and the supporting body 11 may be a flat plate structure or a plate structure with protrusions, depressions or folds on the surface, where it is noted that, when the conductive module is integrally disposed with the supporting body, the conductive module and the supporting body may be a conductive metal plate/conductive structure 12 plate.

In this embodiment, the control power supply 20 includes an ac power supply and a control circuit board, the control circuit board is electrically connected with the ac power supply, the control circuit board is used for regulating and controlling the frequency, current waveform, oscillating voltage of the current output by the ac power supply, and monitoring the thawing state of frozen food in the closed loop, so that the control power supply outputs the oscillating current, it should be noted that the control circuit board may include PLC control, etc., numerical control programs adopted by the control circuit board are all commercially available, and the circuit structure in the control power supply and the manner of achieving constant current output by amplitude modulation control duty ratio are all implemented by means or techniques known to those skilled in the art, and are not limited in this regard.

In this embodiment, at least one of the supporting bodies is further in transmission connection with a second driving mechanism, and can be driven by the second driving mechanism to move to approach or separate from the other supporting body opposite to the second driving mechanism, so that the height of the accommodating space between the two oscillating current emitting assemblies 10 can be adjusted, and the second driving mechanism can be a linear driving mechanism such as a linear driving motor or a cylinder.

It should be noted that, in the present embodiment, only the case of providing two oscillating current transmitting assemblies 10 is shown, of course, four or more oscillating current transmitting assemblies 10 may be provided, for example, when four oscillating current transmitting assemblies 10 are provided, two of the oscillating current transmitting assemblies 10 are disposed opposite to each other along the first direction, the other two oscillating current transmitting assemblies 10 are disposed opposite to each other along the second direction, a receiving space is formed between the four oscillating current transmitting assemblies 10, and the first direction and the second direction are disposed to intersect.

Example 2 Single stage thawing thick cut steak (one polar plate + multiple fixed electrodes + support + Co-constant flow)

The thawing method of the frozen thick cut steak in this example was carried out by the non-thermal thawing apparatus in example 1, in which the thick cut steak was frozen at-15℃and the thick cut steak was uniform in thickness.

Referring to fig. 1 and 2, the non-thermal thawing apparatus according to the present embodiment includes two oscillating current emitting assemblies disposed opposite to each other, wherein the number of electrodes included in one oscillating current emitting assembly is 100, each 5 electrodes are connected to one output (i.e., each 5 electrodes is used as a conductive module, and the same applies to the other electrode), so that the oscillating current emitting assembly includes 20 output leads, the other oscillating current emitting assembly is a unipolar plate (which can be understood as a metal plate with the electrodes and the support body integrally disposed, and the same applies to the other electrode), and includes one output lead as a common terminal, and the 21 output leads of the two oscillating current emitting assemblies are connected to a control power source together, i.e., the control power source simultaneously controls the current intensity, frequency and duration of the oscillating current outputted by 20 paths, and forms up to 20 closed loops at different portions of the thick-cut steak.

The electrode in this embodiment is made of 316 stainless steel, the structure at the top of the electrode is hemispherical and has a diameter of 5mm, the height of the electrode is 20mm, the minimum distance between two adjacent electrodes is 8mm, and all electrodes and output leads are fixed by a support body.

A method for thawing thick cut steaks specifically comprises the following steps:

1) 350g of frozen thick cut steak is taken, the length of the thick cut steak is measured to be 15cm at maximum, the maximum width is 6cm, and the thickness is 3.5cm.

2) The thick cut steak is arranged between the oscillating current emission components, and the two oscillating current emission components are arranged on the upper side and the lower side of the frozen thick cut steak, so that the two oscillating current emission components are respectively in electrical contact with a plurality of areas/parts of the thick cut steak.

3) The thick cut steak is thawed by controlling the power supply to apply a plurality of oscillating currents to the thick cut steak through the two oscillating current transmitting assemblies.

Specifically, the thawing process is set as a stage, the duration is 12min, during thawing, a detection signal (for example, detection oscillation voltage and the like) with an effective value of 200V and a duty ratio of 1% is output first, at this time, an average current effective value of 8mA of 20 paths of output is obtained, after program analysis, the current intensity effective value of each path of output is always kept at 50mA, the current frequency is 2000Hz and the current waveform is oscillation current of square wave by controlling the duty ratio of iterative amplitude modulation output of a power supply, and accordingly, the average current intensity of each electrode output is 10mA.

After thawing, dividing the thick cut steak into 4 blocks, measuring the temperatures of different parts of the thick cut steak by adopting a handheld thermal imager, and checking whether the surface and the section of the thick cut steak have local overheating or are not completely thawing or are locally cured; the results show that the average temperature of the thawed thick cut steak in the embodiment is 0.5 ℃, the highest point temperature is 3.3 ℃, the lowest point temperature is-2.6 ℃, the regional temperature difference is 5.9 ℃, the phenomenon of local overheating or curing does not occur, and the weight loss rate is 4.32%.

Comparative example 1 thawed thick cut steak

The method of thawing the thick cut steak in comparative example 1, and the form, size, etc. of the thick cut steak were substantially the same as those of example 2, and were also carried out using the non-thermal thawing apparatus as in example 1, except that:

in the thawing process, the control power supply controls the current intensity applied by each output circuit to be 3000mA all the time, the average current intensity output by each electrode is 600mA, and the maximum current intensity of each oscillation current applied within the thickness of 8cm is not more than 400mA beyond the technical index of the invention.

After thawing, observing thawing conditions of the thick cut steak: dividing the thick cut steak into 4 pieces, measuring the temperature conditions of different parts of the thick cut steak by adopting a handheld thermal imager, and checking whether the surface and the section of the thick cut steak have local overheating or are not completely unfrozen or are locally cured; the results show that the surface temperature of the thawed thick cut steak in the comparative example 1 reaches 23+/-0.8 ℃, the temperature of the other most parts is 18+/-1.6 ℃, the temperature difference of the area is 12.6 ℃, the surface is cured, namely the surface is whitened due to a large amount of thermal denaturation of protein, and the overall weight loss rate is 15.57%.

Example 3 multistage thawing of irregular Ridge meat (Single plate + multiple Movable electrodes + support + Co-constant flow)

Referring to fig. 3 and 4, the present embodiment is implemented by the non-thermal thawing apparatus of embodiment 1, in which the frozen meat is frozen at-18 ℃.

The non-thermal thawing device used in the present embodiment includes two oscillating current emitting assemblies, wherein one of the oscillating current emitting assemblies includes 80 electrodes, and each 10 electrodes are connected to one output (i.e., each 10 electrodes is used as a conductive module, and the following is the same), so that the oscillating current emitting assembly includes 8 output leads; the other oscillating current emitting component is a monopole board and comprises 1 output lead as a common end, 9 output leads of the two oscillating current emitting components are connected with a control power supply together, namely the control power supply simultaneously controls the current intensity, the frequency and the duration of 8 paths of output oscillating current, and at most 8 closed loops can be formed in different areas/parts of frozen pork in a ridge.

The electrode in this embodiment is made of 304 stainless steel, the structure at the top of the electrode is hemispherical and has a diameter of 5mm, the height of the electrode is 32mm, the minimum distance between adjacent electrodes is 8mm, all electrodes and output leads are fixed by a support body, the movable electrode contains springs, and the maximum telescopic distance of the movable electrode is 12mm.

A method for thawing a meat fillet, comprising:

1) Taking 250g of frozen pork fillet, wherein the length of the pork fillet is 23cm at maximum, the maximum width is 5cm, and the thickness is 2.3-3.5 cm;

2) The frozen pork fillet is arranged between the oscillating current emission components, and the two oscillating current emission components are arranged on the upper side and the lower side of the frozen pork fillet, so that a plurality of electrodes and monopole plates contained in the two oscillating current emission components are respectively in electrical contact with a plurality of areas/parts of the frozen pork fillet; it should be noted that, although the thickness of the meat is not uniform, the electrodes are flexible, so that the meat can be effectively contacted with the monopole plate and the plurality of electrodes and with different areas/portions of the meat;

3) The method comprises the steps that a plurality of oscillating currents are applied to the meat fillet in stages through two oscillating current emitting assemblies by controlling a power supply, so that the meat fillet is thawed, the specific thawing process is divided into three stages according to set time, and the total time is 8min, wherein the three stages are as follows: the early thawing period is 2min, the middle thawing period is 4min, and the final thawing period is 2min.

Pre-thawing period: firstly outputting a detection signal with an effective value of 150V and a duty ratio of 1%, obtaining an average current effective value of 6mA of 8 paths of output at the moment, and after program analysis, enabling each path of output to respectively apply oscillating current with current intensity of 400mA, current frequency of 3000Hz and current waveform of square wave by controlling the duty ratio of iterative amplitude modulation output of a power supply, namely, enabling the average current intensity of the oscillating current provided by each electrode to be 40mA for 2min;

Mid-thawing: the duty ratio of the power supply iterative amplitude modulation output is controlled to enable each output to apply oscillating current with current intensity of 200mA, current frequency of 2000Hz and current waveform of square wave, and the average current intensity of the oscillating current provided by each electrode is 20mA for 4min;

end of thawing: the duty ratio of the power supply iterative amplitude modulation output is controlled to enable each output to apply oscillating current with current intensity of 80mA, current frequency of 1000Hz and current waveform of square wave, and the average current intensity of the oscillating current provided by each electrode is 8mA for 2min.

After the thawing condition of the pork fillet is finished, the pork fillet is divided into 4 blocks, the temperature of different areas of the pork fillet is detected by adopting a handheld thermal imager, and whether the surface and the section of the pork fillet are locally overheated, not completely thawed or locally cured is detected; the results show that the average temperature of the thawed pork fillet in the embodiment is-1.3 ℃, the highest point temperature is 0.4 ℃, the lowest point temperature is-3.4 ℃, the regional temperature difference is 3.8 ℃, the surface overheating phenomenon does not occur, and the weight loss rate is only 3.85%.

Example 4 Multi-stage thawing of irregular salmon (Single plate + multiple Movable electrodes + support + heteroconstant flow)

Referring to fig. 5 and 6, the present embodiment is implemented by the non-thermal freezing apparatus of embodiment 1, in which the frozen salmon is frozen at-20 ℃.

The non-thermal thawing device adopted in the embodiment comprises two oscillation current emission components which are oppositely arranged, wherein the number of electrodes contained in one oscillation current emission component is 45, and each 15 electrodes are connected to form one output path, so that the oscillation current emission component comprises 3 output leads; the other oscillating current transmitting assembly is a unipolar plate and comprises 1 output lead as a common end, 4 output leads of the two opposite oscillating current transmitting assemblies are connected into a control power supply together, namely the control power supply simultaneously controls the current intensity, the frequency and the duration of the oscillating current output by 3 paths, and at most 3 closed loops can be formed in different areas of the frozen salmon.

The electrode in this embodiment is made of aluminum alloy, the structure at the top of the electrode is hemispherical and has a diameter of 3mm, the height of the electrode is 38mm, the minimum distance between adjacent electrodes is 10mm, all electrodes and output leads are fixed through a support body, the movable electrode contains springs, and the maximum telescopic distance of the movable electrode is 30mm.

A method for thawing salmon, comprising the following steps:

1) Taking 150g of frozen salmon, wherein the maximum length of the frozen salmon is 13cm, the maximum width is 6cm, and the thickness is 1.0-4.0 cm;

2) The frozen salmon is placed between two oscillating current emitting assemblies, and the two oscillating current emitting assemblies are arranged on the upper side and the lower side of the salmon, so that the two oscillating current emitting assemblies are respectively contacted with a plurality of areas/parts of the salmon; the 15 electrodes output in the 1 st path are electrically contacted with the region/part with the salmon thickness of 1.0-2.0cm, the 15 electrodes output in the 2 nd path are electrically contacted with the region/part with the salmon thickness of 2.0-3.0cm, and the 15 electrodes output in the 3 rd path are electrically contacted with the region/part with the salmon thickness of 3.0-4.0 cm.

3) The salmon is thawed by applying a plurality of oscillating currents to the salmon in stages through the two oscillating current transmitting assemblies by controlling the power supply, the specific thawing process is divided into four stages according to the setting time, the total time is 8min, and the four stages are set as follows: 1min before thawing, 2min after thawing, 3min after thawing, and 2min after thawing.

In the early stage of thawing, firstly outputting a detection signal with an effective value of 300V and a duty ratio of 1%, obtaining 3 paths of average current effective values of 8mA, 10mA and 13mA respectively at the moment, and after program analysis, controlling the duty ratio of iterative amplitude modulation output of a power supply to enable the current intensity applied by the 1 st path of output to be 300mA, the current frequency to be 1000Hz and the current waveform to be oscillation current of square waves, wherein the average current intensity provided by each electrode is 20mA; the 2 nd output is made to apply oscillation current with current intensity of 450mA, current frequency of 1000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 30mA; the 3 rd output is made to output oscillation current with the current intensity of 750mA, the current frequency of 1000Hz and the current waveform of square wave, and the average current intensity provided by each electrode is 50mA for 1min;

thawing for 2 periods, wherein the duty ratio of the power supply iterative amplitude modulation output is controlled to enable the current intensity applied by the 1 st output to be 120mA, the current frequency to be 2000Hz and the current waveform to be the oscillating current of square waves, and the average current intensity provided by each electrode is 8mA; the 2 nd output is made to apply oscillating current with current intensity of 300mA, current frequency of 2000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 20mA; the 3 rd output is made to output oscillation current with the applied current intensity of 600mA, the current frequency of 2000Hz and the current waveform of square waves, and the average current intensity provided by each electrode is 40mA for 2min;

Thawing for 3 periods, wherein the duty ratio of the power supply iterative amplitude modulation output is controlled to enable the current intensity applied by the 1 st output to be 90mA, the current frequency to be 3000Hz and the current waveform to be the oscillating current of square waves, and the average current intensity provided by each electrode is 6mA; the 2 nd output is made to apply oscillation current with current intensity of 225mA, current frequency of 3000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 15mA; the current intensity of the 3 rd output is 450mA, the current frequency is 3000Hz, the current waveform is oscillation current of square wave, the average current intensity provided by each electrode is 30mA, at the moment, the monopole board is used as a public end to bear the total oscillation current of the 3 outputs of 765mA, and the duration is 3min;

at the end of thawing, the duty ratio of the iterative amplitude modulation output of the power supply is controlled to enable the current intensity applied by the 1 st output to be 75mA, the current frequency to be 1000Hz and the current waveform to be the oscillating current of square waves, and the average current intensity provided by each electrode is 5mA; the 2 nd output is made to apply oscillating current with current intensity of 150mA, current frequency of 1000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 10mA; the 3 rd output was made to output an oscillating current with a current intensity of 300mA, a current frequency of 1000Hz and a current waveform of square wave, and the average current intensity supplied by each electrode was 20mA for 1min.

After the process is finished, the thawing condition of salmon is observed, the salmon is divided into 4 blocks, the temperature of different areas of the salmon is detected by adopting a handheld thermal imager for temperature measurement, and whether the surface and the section of the salmon have local overheating, incomplete thawing or local curing is detected; the results show that the average temperature of the salmon after thawing in the embodiment is-0.7 ℃, the highest point temperature is 1.1 ℃, the lowest point temperature is-0.9 ℃, the regional temperature difference is 2.0 ℃, the phenomenon of surface overheating does not occur, and the weight loss rate is only 2.29%.

Example 5 Multi-stage scanning thawing of irregular breasts (Single plate + multiple moving electrodes + ticker)

This example was performed with the non-thermal thawing apparatus of example 1, in which frozen chicken breasts were frozen at-19.5 ℃.

Referring to fig. 7, the non-thermal thawing apparatus according to the present embodiment includes two oscillating current emitting devices disposed opposite to each other, wherein one of the oscillating current emitting devices includes 120 electrodes, and each 12 electrodes are connected to one output, so that the oscillating current emitting device includes 10 output leads; the other oscillating current emitting component is a unipolar plate and comprises 1 output lead as a common end, and 11 output leads of the two opposite oscillating current emitting components are connected into a control power supply together, namely the control power supply simultaneously controls the oscillating current of 10 paths of output, the frequency and the duration, and the oscillating current of at most 10 closed loops can be formed in different areas of the frozen chicken breast.

The electrode in this embodiment is made of 316 stainless steel, the structure at the top of the electrode is hemispherical and has a diameter of 4mm, the height of the electrode is 6mm, the minimum distance between adjacent electrodes is 9mm, all electrodes are arranged on the support body at intervals, the movable electrode contains springs, and the maximum telescopic distance of the movable electrode is 100mm.

A method for thawing chicken breasts, which comprises the following steps:

1) Taking 660g frozen chicken breasts, wherein the length of the chicken breasts is 20cm at maximum, the maximum width is 15cm, and the thickness is 1.0-11.0 cm;

2) Placing the frozen chicken breast in a containing space between two oscillating current emitting assemblies, wherein the two oscillating current emitting assemblies are arranged on the upper side and the lower side of the frozen chicken breast, so that a plurality of electrodes and unipolar plates contained in the two oscillating current emitting assemblies are respectively in electrical contact with a plurality of areas/parts of the frozen chicken breast; it should be noted that although the thickness of the frozen chicken breast is not uniform, the electrode can be attached to the surface of the chicken breast due to the movable electrode, so that the electrode and the single-pole plate can be in effective electrical contact with different areas/parts of the chicken breast; the correspondence between the 10 output and the different contact areas/parts of the chicken breast is shown in table 1, and the thickness of the contact area/part of the 12 output electrodes of the 1 st output and the chicken breast is 1.0-2.0cm, the thickness of the contact area/part of the 12 output electrodes of the 2 nd output and the chicken breast is 2.0-3.0cm, the thickness of the contact area/part of the 12 output electrodes of the 3 rd output and the chicken breast is 3.0-4.0cm, and the thickness of the contact area/part of the 12 output electrodes of the 10 th output and the chicken breast is 10.0-11.0cm according to the thickness of the chicken breast and the like.

Table 1 shows the correspondence between 10 outputs and different contact areas/portions of chicken breasts

3) The power supply is controlled to sequentially apply oscillating currents to different areas/parts of the chicken breast in a staged manner through the two oscillating current emitting assemblies, so that the chicken breast is thawed, the specific thawing process is divided into three stages according to the set time, the total time is 10min, and the three stages are set as follows: 3min before thawing, 5min in middle thawing and 2min in end thawing.

In the early stage of thawing, firstly outputting a detection signal with an effective value of 180V and a duty ratio of l%, obtaining an average current effective value of 10 paths of outputs which are respectively 4mA, 5mA, 6mA, 7mA, 8mA, 9mA, 10mA, 11mA, 12mA and 13mA at the moment, after program analysis, keeping the oscillating current constant by controlling the duty ratio of the iterative amplitude modulation output of a power supply, and opening only one path of output each time for providing the oscillating current, keeping the other 9 paths of output in a closed state for a period of time, closing the output, then opening the other path of output oscillating current, keeping the other 9 paths of output in the closed state, enabling the 9 paths of output to be sequentially and circularly opened for 10 seconds, forming an output form of the horse race lamp, namely always keeping one path of output in an open state, keeping the cyclic processing process for 3min, and sequentially opening and closing each path of output oscillating current within the 3min of the early stage of thawing, wherein the configuration parameters of the 10 paths of output are shown in the following table 2;

Table 2 shows 10 configuration parameters of the output at the early stage of thawing

The working mode of 10 paths of output in the thawing period is as described above, each path of output is started each time and the other paths of output are closed simultaneously in a horse race lamp mode, the circulation processing process is kept for 5min, the time for completing one circulation is 10s, and therefore each path of output oscillating current is sequentially started and closed for 30 times within the time of 5min in the thawing period; the parameters of the 10 outputs at this time are shown in the following table 3:

table 3 shows 10 configuration parameters of the output in the middle of thawing

The working mode of the 10 outputs at the end of thawing is as described above, each output is turned on by adopting a horse race lamp mode, and the other outputs are turned off at the same time, the circulation processing process is kept for 2min, and the time for completing one circulation is 5s, so that each output oscillating current is turned on and off for 24 times in sequence within the 2min time at the end of thawing, and the configuration parameters of the 10 outputs are shown in table 4:

table 4 shows 10 configuration parameters of the output in the middle of thawing

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After the process is finished, the thawing condition of the chicken breast is observed, the chicken breast is divided into 4 blocks, the temperature conditions of different areas are detected by adopting a handheld thermal imager for temperature measurement, and whether the surface and the section of the chicken breast are locally overheated, not completely thawed or locally cured is observed; the results show that the average temperature of the thawed chicken breast is-1.3 ℃, the highest point temperature is-0.5 ℃, the lowest point temperature is-1.5 ℃, the regional temperature difference is 1.0 ℃, the phenomenon of surface overheating does not occur, and the weight loss rate is only 0.92%.

EXAMPLE 6 multistage thawing of Buddha (irregular sample, movable electrode+support)

This example was carried out with the non-thermal thawing apparatus of example 1, in which frozen balsalazide was frozen at-20 ℃.

Referring to fig. 8, the non-thermal thawing apparatus in this embodiment includes two oscillating current emitting components disposed opposite to each other, each of the oscillating current emitting components includes 90 electrodes, and each of the 3 electrodes is connected to one output, so that a single oscillating current emitting component includes 30 output leads, and is connected to a control power supply together with the 30 output leads of the other oscillating current emitting component, that is, the control power supply controls the magnitude, frequency and duration of the oscillating current outputted by 30 lines, and can form currents of at most 30 closed loops in different areas/portions of frozen balsalads.

The electrode in this embodiment is made of 316 stainless steel, the structure at the top of the electrode is hemispherical and has a diameter of 4mm, the height of the electrode is 30mm, the minimum distance between adjacent electrodes is 12mm, all electrodes and output leads are fixed through a supporting body, the movable electrode contains springs, and the maximum telescopic distance of the movable electrode is 12mm.

A method for thawing ba-sars, comprising the following steps:

1) Taking 400g of frozen ba-sars, wherein the length of the fish body of the ba-sars is 28cm at maximum, the width of the fish body of the ba-sars is 11cm at maximum, and the thickness of the fish body is 1.8-3.0 cm;

2) The frozen balsa is arranged in the accommodating space between the oscillating current emission components, and the two oscillating current emission components are arranged on the upper side and the lower side of the frozen balsa, so that a plurality of electrodes contained in the two oscillating current emission components are respectively contacted with a plurality of areas/parts of the frozen balsa, and the electrodes can stretch and retract to move in spite of uneven thickness of the frozen balsa, so that the arranged electrodes can be in effective electrical contact with different areas/parts of the balsa.

3) The method comprises the steps of applying a plurality of oscillating currents to the balsa fish in stages through two oscillating current transmitting assemblies by controlling a power supply, so that the balsa fish is thawed, the specific thawing process is divided into three stages for 10min according to the setting time, and the three stages are as follows: the early thawing period is 3min, the middle thawing period is 5min, and the final thawing period is 2min.

In the early stage of thawing, firstly outputting a detection signal with an effective value of 230V and a duty ratio of 1%, obtaining 30 paths of average current effective values of 7mA with different outputs at the moment, and after program analysis, controlling the duty ratio of iterative amplitude modulation output of a power supply to enable each path of output to apply oscillating current with current intensity of 150mA, current frequency of 1000Hz and current waveform of square wave respectively, wherein the average current intensity provided by each electrode is 50mA for 3min;

In the thawing medium period, each output path respectively applies oscillating current with current intensity of 90mA, current frequency of 1000Hz and current waveform of square wave by controlling the duty ratio of iterative amplitude modulation output of a power supply, and the average current intensity provided by each electrode is 30mA for 5min;

at the end of thawing, the duty ratio of the power supply iterative amplitude modulation output is controlled to enable each output to apply oscillating current with current intensity of 30mA, current frequency of 1000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 10mA for 2min.

After the process is finished, the thawing condition of the bazaar is observed, the bazaar is divided into 4 blocks, the temperature conditions of different areas are detected by adopting a handheld thermal imager for temperature measurement, and whether the partial overheat, incomplete thawing or partial curing phenomenon exists on the surface and the section of the bazaar is observed; the results show that the average temperature of the defrosted balsa fish in the embodiment is-2.1 ℃, the highest point temperature is 0.2 ℃, the lowest point temperature is-2.8 ℃, the regional temperature difference is 3.0 ℃, the surface overheating phenomenon does not occur, and the weight loss rate is only 3.45%.

Comparative example 2 defrosted ba-sars

The method of thawing the balsa in comparative example 2 and the form, size, etc. of the frozen balsa were substantially the same as in example 6, and also carried out using a non-thermal thawing apparatus as in example 6, except that:

In the defrosting process, the control power supply controls the current intensity of each output to be 150mA for 10min, but the defrosting is not performed in stages, and in the comparative example 2, the positions of a plurality of electrodes are fixed in the same plane, 15 closed loops are formed in the local area of the frozen balsa, so that 15 oscillating currents are applied.

After the thawing is finished, observing the thawing condition of the bazaar, dividing the bazaar into 4 blocks, detecting the temperature conditions of different areas by using a handheld thermal imager for temperature measurement, and observing whether the surface and the section of the bazaar are locally overheated or not, and curing; the results show that in comparative example 2, the thickness of the body of the balsa is irregular due to unadjustable polar heads, the local temperature after thawing reaches 10+/-0.8 ℃, the temperature of the other most areas is-15+/-1.6 ℃, ice crystals remain in the body of the balsa and cannot be cut by a knife, the current intensity of oscillating current applied in the balsa in the thawing process is kept unchanged, each electrode has long contact time with the balsa due to the fact that the emitted current intensity is continuously too high in the late thawing period, and therefore the surface at the position of 3.0cm of the thickness of the balsa is slightly cured, namely the surface is whitened, the protein is denatured, and the part of 1.8cm is still not thawed due to the fact that the electrode is not contacted with the polar heads, and the whole weight loss rate is 11.85%.

Example 7 multistage thawing of sheep (irregular sample, movable electrode+support)

This example was performed with the non-thermal thawing apparatus of example 1, in which frozen sheep were frozen at-20 ℃.

Referring to fig. 9, the non-thermal thawing apparatus in this embodiment includes two oscillating current emitting devices disposed opposite to each other, wherein each oscillating current emitting device includes 60 electrodes, and each 20 electrodes are connected to one output, so that the oscillating current emitting device includes 3 output leads, and is connected to a control power supply together with the 3 output leads of the other oscillating current emitting device, that is, the control power supply controls the oscillating current size, frequency and duration of the 3 output leads, and can form at most 3 oscillating currents in different areas/portions of the frozen mutton chop.

The electrode in this embodiment is made of 316 stainless steel, the structure at the top of the electrode is hemispherical and has a diameter of 5mm, the height of the electrode is 48mm, the minimum distance between adjacent electrodes is 12mm, all electrodes and output leads are fixed through a supporting body, the movable electrode contains springs, and the maximum telescopic distance of the movable electrode is 30mm.

A method for thawing mutton chops, which comprises the following steps:

1) Taking 250g frozen mutton chop, wherein the length of the mutton chop is 20cm at maximum, the width of the mutton chop is 8cm at maximum, and the thickness of the mutton chop is 3.5-6.5cm;

2) The frozen mutton chop is arranged in a containing space between the oscillating current emission components, and the two oscillating current emission components are arranged on the upper side and the lower side of the frozen mutton chop, so that a plurality of electrodes contained in the two oscillating current emission components are respectively contacted with a plurality of areas of the frozen mutton chop; although the thickness of the frozen mutton chop is uneven, the electrode can stretch and retract, so that the arranged electrode can be in effective electrical contact with different areas/parts of the mutton chop; wherein, the thickness of the sheep chop contacted with the 20 pairs of electrodes output in the 1 st path is 3.5-4.5cm, the thickness of the sheep chop contacted with the 20 pairs of electrodes output in the 2 nd path is 4.5-5.5cm, and the thickness of the sheep chop contacted with the 20 pairs of electrodes output in the 3 rd path is 5.5-6.5cm.

3) The power supply is controlled to apply a plurality of oscillating currents to the mutton chop in stages through the two oscillating current emitting assemblies, so that the mutton chop is thawed, the specific thawing process is divided into three stages for 12min according to the set time, and the three stages are as follows: 3min before thawing, 6min in middle thawing and 3min in end thawing.

In the early stage of thawing, a detection signal with an effective value of 280V and a duty ratio of 1% is output firstly, at this time, 3 paths of current effective values of 10mA,12mA and 15mA which are different in output are obtained, after program analysis, the current intensity applied by the 1 st path of output is 1000mA, the current frequency is 2000Hz, the current waveform is oscillation current of square wave, and the average current intensity provided by each electrode is 50mA; the 2 nd output is made to apply oscillating current with current intensity of 1400mA, current frequency of 2000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 70mA; the 3 rd output is enabled to output oscillation current with the applied current intensity of 1800mA, the current frequency of 2000Hz and the current waveform of square waves, the average current intensity provided by each electrode is 90mA, and the duration is 3min;

In the thawing medium period, the duty ratio of the power supply iterative amplitude modulation output is controlled to enable the current intensity applied by the 1 st output to be 800mA, the current frequency to be 1000Hz and the current waveform to be the oscillating current of square waves, and the average current intensity provided by each electrode is 40mA; the 2 nd output is made to apply oscillating current with current intensity of 1200mA, current frequency of 1000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 60mA; the 3 rd output is enabled to output oscillation current with the applied current intensity of 1600mA, the current frequency of 1000Hz and the current waveform of square waves, and the average current intensity provided by each electrode is 80mA for 6min;

at the end of thawing, the duty ratio of the iterative amplitude modulation output of the power supply is controlled to enable the current intensity applied by the 1 st output to be 600mA, the current frequency to be 1000Hz and the current waveform to be the oscillating current of square waves, and the average current intensity provided by each electrode is 30mA; the 2 nd output is made to apply oscillating current with current intensity of 800mA, current frequency of 1000Hz and current waveform of square wave, and the average current intensity provided by each electrode is 40mA; the 3 rd output is enabled to output oscillation current with the applied current intensity of 1200mA, the current frequency of 1000Hz and the current waveform of square waves, and the average current intensity provided by each electrode is 60mA for 3min;

After the completion, the thawing condition of the mutton chop is observed, the mutton chop is divided into 4 pieces, the temperature conditions of different areas are detected by adopting a handheld thermal imager for temperature measurement, and whether the local overheating, incomplete thawing or local curing phenomena exist on the surface and the section of the mutton chop or not is observed; the results show that the average temperature of the thawed sheep chops in the embodiment is-1.2 ℃, the highest point temperature is-0.4 ℃, the lowest point temperature is-2.5 ℃, the regional temperature difference is 2.1 ℃, the phenomenon of surface overheating does not occur, and the weight loss rate is only 2.43%.

Example 8 multistage scanning thawing of 25kg frozen chicken coops (irregular sample, moving electrode+ticker)

This example was performed using the non-thermal thawing apparatus of example 1, in which frozen chicken nuggets were frozen at-20.0 ℃.

Referring to fig. 10, the non-thermal thawing apparatus in this embodiment includes two oppositely disposed oscillating current emitting components, each of which includes 220 electrodes, and each of which is connected to one output of 10 electrodes, so that the oscillating current emitting component includes 22 output leads and is connected to a control power supply together with the 22 output leads of the other oscillating current emitting component, that is, the control power supply controls the magnitude, frequency and duration of the oscillating current outputted by 22 paths at the same time, and can form at most 22 oscillating currents in different frozen chicken giblets; the electrode is made of 316 stainless steel, the top of the electrode of the oscillating current emission component is hemispherical and has a diameter of 10mm, the height of the electrode is 6mm, the minimum distance between adjacent electrodes is 12mm, all electrodes and wires are fixed through a supporting body, the movable electrode contains a spring, and the maximum telescopic distance of the movable electrode is 30mm.

A method for thawing chicken offal, comprising the following steps:

1) Taking 25kg of frozen chicken giblets, tearing the packaging bag, and measuring the maximum length of the whole frozen chicken giblets to be 52cm, the maximum width to be 25cm and the thickness to be 12.0-15.0cm;

2) The whole frozen chicken giblets are arranged in the accommodating space between the oscillating current emitting assemblies, and the two oscillating current emitting assemblies are arranged on the upper side and the lower side of the frozen chicken giblets, so that a plurality of electrodes contained in the two oscillating current emitting assemblies are respectively in electrical contact with a plurality of areas/parts of the whole frozen chicken giblets, and the electrodes in the whole frozen chicken giblets can be in telescopic movement although the thickness of the whole frozen chicken giblets is slightly uneven, so that the arranged electrodes can be in effective contact with different areas of the whole frozen chicken giblets; wherein the thickness of the whole chicken giblets contacted with 70 pairs of electrodes of outputs 1, 2, 3, 4, 5, 6 and 7 is 12.0-13.0cm, the thickness of the whole chicken giblets contacted with 80 pairs of electrodes of outputs 8, 9, 10, 11, 12, 13, 14 and 15 is 13.0-14.0cm, the thickness of the whole chicken giblets contacted with 70 pairs of electrodes of outputs 16, 17, 18, 19, 20, 21 and 22 is 14.0-15.0cm, and the configuration parameters of the outputs 22 are shown in table 5:

table 5 shows configuration parameters for 22-way output

3) The method comprises the steps that a plurality of oscillating currents are applied to frozen chicken giblets in stages through two oscillating current emitting assemblies by controlling a power supply, so that the frozen chicken giblets are thawed, the specific thawing process is divided into three stages for 15min in total according to set time, and the three stages are set as follows: the early thawing period is 4min, the middle thawing period is 8min, and the final thawing period is 3min.

In the early stage of thawing, firstly, a detection signal with an effective value of 240V and a duty ratio of 1% is output, at this time, an average current effective value of 22 paths of output is 10mA, after program analysis, the oscillating current is kept constant by controlling the duty ratio of iterative amplitude modulation output of a power supply, and only one path of output is started each time for providing the oscillating current, the other 21 paths of output are kept in a closed state, and the path of output is closed after a period of time; then, starting the other path of output oscillating current, and simultaneously keeping the other 21 paths of output in a closed state, and sequentially circulating to form an output form of the horse race lamp, namely keeping the output on state of one path all the time, wherein the circulating treatment process keeps 4min, and the parameters of the 22 paths of output are shown in a table 6;

table 6 shows configuration parameters of 22-way output at the early stage of thawing

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The time for completing one cycle is 24s, so that each output oscillating current is turned on and off for 10 times in turn within 4min of the earlier thawing period.

In the middle period of thawing, the power supply is controlled to operate in the same way, each output is turned on in a horse race lamp mode, and other outputs are turned off at the same time, the cyclic treatment process is kept for 8min, and parameters of 22 outputs are shown in table 7:

table 7 shows 22 configuration parameters of the output at the mid-thawing period

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The time for completing one cycle is 24s, so that each output oscillating current is turned on and off for 20 times in sequence within 8min in the middle of thawing.

At the end of thawing, the power supply is controlled to operate in the same way, each output is turned on in the form of a horse race lamp, and the other outputs are turned off at the same time, the cyclic processing process is kept for 3min, and parameters of 22 outputs are shown in table 8:

table 8 shows configuration parameters for 22 outputs at the end of thawing

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The time for completing one cycle is 10s, so that each output oscillating current is sequentially turned on and off for 18 times within 3min at the end of thawing.

After the process is finished, the thawing condition of the frozen chicken offal is observed, the whole chicken offal is broken off, a part is selected to be cut after single dispersion, the temperature conditions of different areas are detected by adopting a handheld thermal imager for temperature measurement, and whether the local overheating, incomplete thawing or local curing phenomena exist on the surface and the section of the chicken offal or not is observed; the results show that the average temperature of the chicken giblets after thawing in the embodiment is-0.3 ℃, the highest point temperature is 0.2 ℃, the lowest point temperature is-0.7 ℃, the regional temperature difference is 0.9 ℃, the surface overheating phenomenon does not occur, and the weight loss rate is only 0.94%.

It should be noted that, in embodiments 2 to 8 of the present invention, the non-thermal thawing apparatus in embodiment 1 is directly performed in the thawing space in the electric appliance having the thawing function, and of course, may be directly performed in other open spaces.

The non-thermal thawing device provided by the invention has a simple structure, can be suitable for thawing treatment of frozen foods in different forms, and can simultaneously thaw a plurality of different parts of the frozen foods in the thawing process of the frozen foods, so that the thawing process is more uniform and efficient; according to the thawing method of frozen food, specific oscillating current is applied to each part of the frozen food in a staged and periodic manner, and different parts of the frozen food can intermittently receive energy under the scanning treatment flow, namely, the rapid application of a horse race lamp is facilitated, so that the uniform ablation of ice crystals in the frozen food is facilitated; compared with constant thawing of oscillating current, the invention can further prevent the phenomena of overhigh short-time aggregation energy and local overheating of the surface, and the juice loss of frozen food is less; compared with the staged simultaneous thawing, the frozen food has better ice crystal ablation linearity, so the temperature difference of the area of the inner section of the frozen food at the thawing end point is smaller, and the quality of the thawed food is higher.

The thawing method of frozen food provided by the invention is a non-thermal thawing technology for thawing by utilizing multi-part applied micro-current, and the micro-current is applied to irregular food materials to achieve the balance point of destroying ice crystal energy, so that uniform non-thermal thawing can be realized, and the thawing method can be popularized to civil and industrial ends.

It should be noted that the foregoing embodiments are merely exemplary of the present invention, and various process conditions are typical examples, but the inventors have proved through numerous experiments that other process conditions listed above are applicable and achieve the technical effects claimed in the present invention.

It should be understood that the above embodiments are merely for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and implement the same according to the present invention without limiting the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.

Claims

1. A method for thawing frozen food, characterized by: the thawing method comprises m thawing stages, each thawing stage comprises n thawing periods, each thawing period comprises the step of sequentially applying oscillating current to x parts of frozen food, wherein the heat generated by the oscillating current in the frozen food is the same as or slightly greater than the energy required by ice crystals in the frozen food to be converted into liquid water, so that the frozen food is thawed, the thawing end temperature of the inner area of the frozen food is not more than 15 ℃, and m, n, x is more than or equal to 1, m, n and x are integers.

2. The thawing method as defined in claim 1, wherein each of the thawing cycles includes: applying y oscillating currents to one or more parts of the frozen food each time, wherein y is more than or equal to 1, and y is an integer;

preferably, the oscillating current is applied periodically to one portion of the frozen food product at a time during each thawing cycle, the period of application of the oscillating current being between 0.1 and 10 minutes.

3. The thawing method according to claim 1 or 2, characterized in that: the thickness of the x portions of the frozen food product is the same or different, and the current intensity of the oscillating current applied to the x portions of the frozen food product is positively correlated to the thickness of each portion of the frozen food product.

4. A defrosting method as claimed in claim 3, characterized in that: the frozen food has a thickness of 15cm or less; preferably, the current intensity of each oscillating current is 3-2000mA, the current frequency is 1Hz-100kHz, and the current intensity is an effective value; and/or the current waveform of the oscillating current is a square wave or a sawtooth wave.

5. The thawing method as defined in claim 4, wherein: the thickness of a selected portion of the frozen food product corresponds to a current intensity of an oscillating current applied to the selected portion of 0.5-15cm:3-2000mA;

Preferably, when the thickness of the selected portion of the frozen food product is 0.5-8cm, the current intensity of the oscillating current applied to the selected portion is 3-400mA;

when the thickness of the selected portion of the frozen food product is 8-15cm, the current intensity of the oscillating current applied to the selected portion is 400-2000mA.

6. The thawing method according to claim 1 or 2, characterized by comprising: decreasing the gradient of the oscillating current applied to the same portion of the frozen food in the m thawing phases, while maintaining the same holding time of the oscillating current applied to the same portion of the frozen food in the m thawing phases, or maintaining the same gradient of the oscillating current applied to the same portion of the frozen food in the m thawing phases, while decreasing the gradient of the holding time of the oscillating current applied to the same portion of the frozen food in the m thawing phases;

preferably, the time of each thawing stage is 0.1-10min;

preferably, for the same closed loop, the current intensity of the oscillating current applied in the mth thawing stage is 20-80% of the current intensity of the oscillating current applied in the mth-1 thawing stage, or, for the same closed loop, the holding time of the oscillating current applied in the mth thawing stage is 20-80% of the holding time of the oscillating current applied in the mth-1 thawing stage, and (m-1) > 1.

7. The thawing method as defined in claim 1, characterized in that it comprises in particular: at least one group of conductive modules electrically connected with a control power supply are electrically contacted with frozen food, at least one closed loop is formed between each group of conductive modules and a part of the frozen food, and the oscillating current is sequentially applied into the closed loop by the control power supply, wherein the group of conductive modules comprises two conductive modules which are respectively electrically connected with two different terminals of the control power supply;

preferably, the thawing treatment specifically includes: contacting a plurality of groups of conductive modules electrically connected with a control power supply with x parts of frozen food, forming a plurality of closed loops between the plurality of groups of conductive modules and the plurality of parts of frozen food, and sequentially applying a plurality of oscillating currents into the plurality of closed loops by the control power supply, wherein each part of frozen food at least corresponds to one closed loop;

preferably, each conductive module comprises one or more conductive structures, and a plurality of conductive structures contained in each conductive module are connected in series and/or in parallel;

Preferably, a plurality of conductive structures included in each conductive module are arranged at intervals, and a distance between two adjacent conductive structures is 1-30mm.

8. The thawing method as defined in claim 7, further comprising: the current intensity of the oscillating current applied to the selected portion of the frozen food product is maintained constant during the defrost cycle.

9. The thawing method as defined in claim 8, characterized in that it comprises in particular: and monitoring the oscillating current in the closed loop corresponding to the selected part by using ohm law through an oscillating voltage, and adjusting the current intensity applied to the corresponding closed loop according to the duty ratio of the oscillating voltage in the closed loop so as to keep the current intensity of the oscillating current in the closed loop constant, wherein the effective value of the oscillating voltage is 20-300V, and the duty ratio is 1-99%.

10. The thawing method as defined in claim 1, wherein: the thawing end temperature of the inner region of the frozen food is-4-15 ℃; preferably, the frozen food product comprises a frozen seafood product, a frozen meat product or a frozen flour product.