JP2002272436A - Freezing method and thawing method, and refrigeration apparatus and thawing apparatus - Google Patents

Abstract

(57) [Summary] [Problem] To be able to refine ice crystals and homogenize the state of freezing, suppress the mechanical destruction of cell tissues, and suppress the chemical change of cell colloids, and to enhance the taste of fresh foods and the like. Provided are a refrigeration method, a thawing method, a refrigeration apparatus, and a thawing apparatus capable of preventing a decrease in quality such as nutrition. SOLUTION: A frozen protection substance made of a dielectric material is coated or added to the surface or inside of a frozen body such as fresh food, and the frozen body is irradiated with an electromagnetic wave, and is absorbed by the frozen body by the electromagnetic wave irradiation. Cool with more energy than is done. In particular, as the electromagnetic wave, a specific frequency is used in which the relative dielectric loss factor of the cryoprotectant solution and the coagulated material is substantially the same, or the coagulated material exceeds the relative dielectric loss factor of the solution. In addition, defrosting is performed using the electromagnetic wave having the unique frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to seafood, livestock products,
The present invention relates to a freezing method, a thawing method, a refrigeration apparatus, and a thawing apparatus for fresh foods such as vegetables and fruits, processed foods such as confectionery, cell tissues such as organs and blood.

[0002]

2. Description of the Related Art Cryopreservation is an extremely effective method for preventing spoilage in preserving fresh foods, processed foods, cell tissues and the like for a long period of time, but has been pointed out as a problem of deteriorating quality. ing. For example, prior literature (Kato Shunro: "Theory and application of food freezing", p312-p40.68
7, 1993, Korin Publishing) states that changes in meat quality caused by the frozen state of meat and seafood include growth or volume expansion due to the formation of ice crystals in the meat, compressing the intercellular structures and cell membranes. Tissues that cause mechanical destruction, and the concentration and composition of water changes (freeze-concentration) due to the freezing-out of water (bound water) that has bound to cellular tissues, and the surface of cytoplasm such as proteins and membrane surfaces It is described that some of the nearby colloidal substances (cellular colloids) have a colloidal structure in which a chemical change occurs.

[0003] When such a change in meat quality occurs, the water that has been frozen and precipitated when the frozen food is thawed cannot be absorbed by the meat quality (sponge), and a sap outflow (so-called drip) occurs. It leads to quality deterioration. Since drip contains nutrients such as taste components and water-soluble vitamins, there is a problem in that spilling of the drip impairs taste or causes loss of nutrition.

[0004] Therefore, after freezing fresh foods, the taste,
In order to maintain nutrition, mechanical destruction of the cell tissue,
It is necessary to suppress the chemical change of cell aggregates, and it is particularly important to reduce the size of ice crystals and to suppress freeze concentration.

As these measures, quick freezing, that is,
A method of shortening the time required to pass through the maximum ice crystal formation zone (the temperature range in which ice crystals of -1 to -5 ° C grow most, although it varies depending on the object to be frozen) (hereinafter referred to as the effective freezing period). There is. About 60-80% of the water in the food is free water (water that does not bind to cellular tissues), most of which freeze within the effective freezing period. By shortening the effective freezing period, ice crystals can be miniaturized, and cell destruction can be prevented. As a means for the quick freezing, for example, a large refrigeration facility or a low-temperature liquid gas such as liquid nitrogen is used.

JP-A-8-252082 discloses a rapid cooling process of relatively rapidly cooling from room temperature to a temperature near the freezing point.
A method is disclosed in which a slow cooling process of cooling at a slow cooling rate of 0.5 ° C./hour is performed and the product is not frozen and stored in a temperature range below the freezing point. Further, as the unfrozen state, there are shown a case where the whole body to be frozen is kept in a supercooled state (a liquid state below the freezing point) and a case where only the inside of the cell is kept in an unfrozen state. A refrigeration method that rapidly freezes at a temperature equal to or lower than the temperature at which the supercooled state breaks (breaking point) is also disclosed. Further, the publication discloses that a supercooled state can be stabilized by irradiating a microwave of 500 MHz to 5 GHz band or the like in the process of the slow cooling process.

Further, Ichikawa et al.'S reference (cell Vo23 (4), p1
3.5562-p13.566, 1991) also shows another effect of microwaves. By irradiating rat hepatocytes with microwaves and freezing them, the ice crystals in the cells can be refined, and the cell tissue It is disclosed that ice crystal growth in the inside can be suppressed.

Further, as a measure for suppressing cell destruction, for example, a method of adding an antifreezing agent to a frozen body has been studied. For example, JP-A-6-133687 discloses that by containing maltose or dextrin and maltotetraose in taro and storing them in a frozen state, cell destruction and aging of starch can be suppressed, and sponge formation can be prevented. ing.

Japanese Patent Application Laid-Open No. Hei 5-130829 discloses a method for covering a frozen object with a sheet for preservation to prevent destruction of cell tissues and maintain freshness for a long period of time.

[0010]

However, the above-mentioned conventional method is effective for freezing fresh food and the like and preventing its decay for a long period of time. There was such a problem.

In a large freezing apparatus or a rapid freezing method using a low-temperature liquid gas, for example, a large frozen object such as tuna requires several minutes to several hours to complete freezing. The difference in the state of freezing progress inside increases. As described above, when the freezing progress state varies, the water moves from a low freezing rate (the ratio of the frozen water) to a high freezing rate, and the freeze concentration proceeds. In addition, if the size of the ice crystals varies, the small ice crystals are taken in by the large ice crystals during the freezing storage and tend to be enlarged, which causes destruction of the cell tissue. Further, if the surface freezes first, the internal pressure changes due to the expansion pressure of the ice, and there is another problem that the surface is cracked. Furthermore, in a low temperature zone of -60 ° C or lower, the growth rate of ice crystals is slow but the generation rate is large, and a large amount of fine ice crystals are generated, so that bound water which is difficult to freeze near the surface of the frozen object is forcibly precipitated. On the contrary, there was also a problem of lowering the quality. In addition, the method using a low-temperature liquid gas has a problem that running costs are increased.

In the slow cooling process and the microwave irradiation, the supercooled state is easily maintained, but it is difficult to control because it is easily destroyed by disturbance such as vibration. In the slow cooling treatment, if the treatment is performed in an unfrozen state in the cells, the ice crystals outside the cells become large, and there is a risk that destruction of cell tissues and freeze-concentration proceed to promote colloidal changes. Furthermore, the processing at a cooling rate of 0.01 to 0.5 ° C./hour has a problem that it takes too much time to complete freezing.

[0013] In microwave irradiation, water is easily heated by dielectric heat, and a strong electric field cannot be irradiated. Therefore, its effect is limited. Furthermore, once the supercooled state is destroyed and the microwave is irradiated in the solid-liquid coexistence state, the liquid phase part is preferentially dielectric-heated. There is also a problem that the size is further increased and freeze concentration is promoted.

In addition, when an antifreezing agent is added to a frozen body, it is necessary to devise selection and combination of the antifreezing agent, and it has been difficult to maintain the taste and nutrition at a high level.

[0015] Also, simply covering with a storage sheet,
Although improvement was observed, taste and nutrition could not be maintained at a high level.

The present invention has been made to solve the above-mentioned problems, and suppresses the mechanical destruction of cell tissues and the chemical change of cell colloids, and provides a high quality of fresh foods such as taste and nutrition. It is an object of the present invention to provide a refrigeration method, a thawing method, a refrigeration apparatus, and a thawing apparatus capable of preventing a decrease.

[0017]

According to a first refrigeration method according to the present invention, a cryoprotective substance made of a dielectric material is coated on or added to the surface of an object to be frozen, and electromagnetic waves are applied to the object to be frozen. Irradiation is performed to cool the object to be frozen by cooling with energy larger than energy absorbed by the object to be frozen by the electromagnetic wave irradiation.

In a second refrigeration method according to the present invention, the electromagnetic wave according to the first invention has a frequency at which the relative dielectric loss factor of the solid of the aqueous solution containing the cryoprotectant exceeds the relative dielectric loss factor of the aqueous solution. It is like that.

In a third refrigeration method according to the present invention, the electromagnetic wave of the first invention has a frequency in a range of 10 MHz to 300 MHz.

In a fourth refrigeration method according to the present invention, the means for irradiating electromagnetic waves of the first invention is an antenna.

According to a fifth refrigeration method according to the present invention, the electromagnetic wave irradiating means of the first invention is provided by a TEM cell (Transv.
(erse Electromagnetic) cell.

A sixth refrigeration method according to the present invention is characterized in that the relative dielectric loss factor of the cryoprotective substance or the aqueous solution containing the cryoprotective substance at the cryopreservation temperature of the body to be frozen is the same as that of the refrigeration body. It has a frequency band higher than the relative dielectric loss factor at the freezing point of the body.

In a seventh refrigeration method according to the present invention, the lyoprotectant of the first invention may comprise at least a saccharide, a glycoprotein, a glycolipid, a polyhydric alcohol, a polymer of a polyhydric alcohol, a lipid. Is included.

According to an eighth refrigeration method of the present invention, the cryoprotectant of the seventh invention is characterized in that at least glucose, fructose, sucrose, trehalose, maltose, lactose, fructooligosaccharide, glycoprotein, glycolipid, ethylene Any of glycol, glycerin, glyceride,
Alternatively, it contains any of these polymers.

In a ninth refrigeration method according to the present invention, the coating of the first invention is performed on a sheet on which a cryoprotective substance is applied or interposed.

According to a tenth refrigeration method of the present invention, the electromagnetic wave irradiation of the first invention is performed before the frozen object reaches the freezing point and until the lower limit of the maximum ice crystal formation zone is exceeded. It is.

A first defrosting method according to the present invention defrosts a frozen body using electromagnetic waves having the frequency of the second or third invention.

A first refrigeration apparatus according to the present invention comprises: means for generating an electromagnetic wave according to any of the second to fifth inventions; means for irradiating the object to be frozen with the electromagnetic wave and heating; Means for cooling the object to be frozen by irradiating the object with cooling energy higher than the energy for heating the object to be frozen.

A first thawing apparatus according to the present invention includes the means for generating electromagnetic waves according to any one of the second to fifth aspects, and means for irradiating the frozen body with the electromagnetic waves and heating the same. It is.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, the present invention will be described.
Embodiments will be described with reference to mathematical expressions and drawings. By electromagnetic wave irradiation
The energy P to heat the dielectric_h[W / m^Three]
This can be expressed by the following equation. P_h= (1 / 1.8) × f × v^Two× ε_r"× 10^-Ten (1) ε_r"= Ε_r'× tan δ (2) where f [Hz] is a frequency and v [V / m] is a large electric field.
Size, ε_r"Is the relative dielectric loss factor, ε_r'Is the relative permittivity, ε₀Is a vacuum
Tanδ is the dielectric loss angle. Accordingly
From the above equation (1), the dielectric heating energy P_hIs
Specific dielectric loss factor of material ε _r"Is proportional to
Dielectric material that the dielectric material stores as a capacitor per half cycle
Energy p_i[W] is p_i= Π × v^Two× ε_r'× ε₀ (3) expressed by the dielectric energy p_iPart of the water before freezing
Minimize molecular clusters to suppress ice crystal growth
The effect increases as the electric field increases.
Good.

The inventors have studied the frequency dependence of the relative dielectric loss factors of water and ice in detail based on the above formula. And, a document by Hippel et al. (ARVon Hippel: Dielectric Mate)
rialsand Application, MIT Press 1954), Ellison et al. (Ellison WJ, J Moreau: J. Mol. Liq. Vol.68, No.2 /
3, p171-279, 1996), Manabe et al. (Takeshi Manabe, H. LIEB)
E, G. Hufford: IEICE Technical Report, vol.87, No.367, p1-6,1
988), and Hufford et al. (G Hufford: Int. J. of I
nfrared and Millimeter Waves, Vol.12, No.7, p.677-68
In view of the data of 2,1991), the dielectric constant of water and ice shown in Figure 1 epsilon _r ', and the relative dielectric loss factor epsilon _r "and give the relation between the frequency. Then, dielectric loss factor on water and ice The characteristic curves of frequency and frequency are shown in frequency bands approaching each other (10 kHz to 150 MHz).
Hz).

Accordingly, the object to be frozen is irradiated with an electromagnetic wave including a frequency band in which the relative dielectric loss factor-frequency characteristic curve is closer to the other frequency band, and the energy is larger than the energy for heating the object to be frozen by the electromagnetic wave irradiation. Cooling not only has the effect of suppressing ice growth like microwaves, but also prevents dielectric heating concentrated on the liquid phase portion of the frozen object, so the surface and inside of the frozen object and the entire frozen object Over time, and can be frozen without promoting freeze concentration. As a result, the amount of drip can be reduced, and freezing with less deterioration in quality can be performed.

Embodiment 2. 0.001N saline solution, 10% sucrose aqueous solution, 30% PEG600 (polyethylene glycol, high molecular weight polymer 600) aqueous solution, and Econa oil (trade name, manufactured by Kao Corporation, in vivo (Based mainly on diacylglyceride, a kind of glyceride), at a frequency of 40.68 MHz or 13.56 MHz at a specific dielectric loss factor (ε _r ) of liquid and solid.
2 and 5, the relative dielectric loss factor greatly changes depending on the temperature, and the relative dielectric loss factor of the 0.001N saline solution in FIG. 3 and 4 (measured at a frequency of 40.68 MHz).
For 0% sucrose aqueous solution and 30% PEG600 aqueous solution, the relative dielectric loss factor below the freezing point (solid) is higher than the freezing point (liquid).
Turned out to be bigger. The econa oil in FIG. 5 (measured at a frequency of 13.56 MHz) did not reach the freezing point (about -25 ° C.), but the relative dielectric constant decreased to a normal freezing temperature level (−10 ° C. to −20 ° C.). It was found that the loss ratio was high.

Furthermore, in the 1-10% sucrose solution, the relative dielectric loss factor of the liquid and solid (ε _r ") and was measured the relation between the frequency, as shown in FIG. 6, the liquid epsilon _r" Is 5
It becomes minimum around 0 MHz, and the higher the concentration of the aqueous solution, the higher the ε
_r "was found to be small. Further, in a 10% aqueous sucrose solution, the relationship between the relative dielectric loss factor ratio of a solid and a liquid (near the freezing point) and frequency was examined. As shown in FIG. From 10 MHz to 100 MHz, it was found that there is a peculiar frequency region where the relative dielectric loss of water and the relative dielectric loss of ice are reversed, where the temperature of the solid is −10 ° C. and the temperature of the liquid is 0 ° C. is there.

As shown in FIGS. 8 to 10, a 5% trehalose aqueous solution, a 10% glucose aqueous solution, and a 30% P
Similarly, in the EG600 aqueous solution, a peak exists around 10 MHz to several hundred MHz. In addition, although the frequency bands are different from each other, it has been found that there is a peculiar frequency region where the relative dielectric loss factor of the solid is larger than that of the liquid.

The substance having a unique dielectric property as described above has, in itself or an aqueous solution thereof, a frequency band in which the relative dielectric loss factor at the freezing storage temperature is higher than the relative dielectric loss factor at the freezing point of the frozen object. . The freezing point of a frozen body such as fresh food is usually about -2 to 0C, and the cryopreservation temperature is usually about -10 to -20C for home use.

Therefore, a substance having a specific dielectric property in which the relative permittivity of the solid (ice) of the cryoprotectant or the aqueous solution containing the cryoprotectant exceeds the relative permittivity of the aqueous solution is defined as the cryoprotectant. Applying or adding to the surface of the frozen body and irradiating it with electromagnetic waves in this peculiar frequency band not only makes it possible to miniaturize the ice crystals, but also makes the freezing progress uniform, so that freeze concentration is suppressed. Drip amount can be reduced, and taste and nutrition can be maintained at a high level.

In addition, even if the frozen point is low, such as econa oil, the relative dielectric loss factor at the frozen storage temperature of the frozen object is higher than the relative dielectric loss factor at the freezing point of the frozen object. Since it has a unique dielectric property having, as a cryoprotectant, it is applied to the surface of the object to be frozen or added to the inside of the body to be frozen and irradiated with electromagnetic waves in this unique frequency band, similarly, freeze concentration is suppressed. To reduce the amount of drip and maintain a high level of taste and nutrition.

In this embodiment, sucrose, trehalose, glucose, PEG, econa oil and the like are used as cryoprotective substances. Or a polysaccharide obtained by polymerizing these. Further, polyhydric alcohols such as glycerin may be used. In addition, lipids containing glyceride as a main component other than econa oil may be used.

As a method for applying the above-mentioned cryoprotectant to the surface of the object to be frozen, there are methods such as brushing, spraying and showering. Further, the cryoprotectant may be dispersed inside the body to be frozen or may be immersed in the cryoprotectant solution for impregnation. It may be poured into the frozen object, or may be mixed and dispersed in the frozen object in advance.

In this embodiment, when the surface of the object to be frozen is covered with the above-mentioned cryoprotective substance, the surface side where freezing proceeds before the inside of the object to be frozen can be preferentially subjected to dielectric heating. The progress of freezing (freezing rate) between the surface and the inside can be made uniform. When the above-mentioned cryoprotective substance is added to the inside of the frozen body, for example, if the inside of the frozen body is sufficiently impregnated with an aqueous solution containing the cryoprotective substance, a difference in the freezing rate can be similarly reduced in the entire frozen body. .

In the present embodiment, when the cryoprotectant capable of exhibiting the above-mentioned action is already contained in the object to be frozen, electromagnetic wave irradiation may be performed by using the cryoprotectant without adding or coating.

Embodiment 3 FIG. 11 is an explanatory diagram showing a method of freezing fresh food or the like according to Embodiment 3 of the present invention in relation to temperature and time. In this freezing method, first, the object to be frozen is cooled, and irradiation of electromagnetic waves is started when the temperature of the surface of the object to be frozen reaches a refrigeration temperature (normally, about 5 ° C. to a freezing point). At this time, the temperature of the object to be cooled is reduced by cooling the object to be cooled with energy larger than the energy heated by absorbing the electromagnetic wave. When the maximum ice crystal formation zone upper limit (freezing point) is reached, the freezing of the surface of the object to be frozen and the center of the object to be frozen proceed at approximately the same temperature. When the temperature inside the frozen object exceeds the lower limit of the maximum ice crystal formation zone, the free water not bound to the cell tissue is almost frozen, and the bound water in the cell tissue remains in an unfrozen state. Furthermore, while irradiating the electromagnetic waves, the temperature of the object to be frozen is further lowered, and the object is frozen to a predetermined frozen storage temperature. The above cryopreservation temperature is -10 for home use.
It is about -20 ° C, and may be -60 ° C or less for business use.

In the present embodiment, the electromagnetic wave irradiation period is set from the time when the temperature of the surface of the object to be frozen reaches the refrigeration temperature (about 5 ° C. to 10 ° C.) and before the bound water is frozen. The irradiation may be performed by appropriately selecting the periods A, B, and C separately and appropriately. Period A: Refrigeration temperature to the upper limit of the maximum ice crystal formation zone (until free water reaches the freezing point from an unfrozen state). Period B: Upper limit to lower limit of the maximum ice crystal formation zone (free water is freezing, free water is almost completely frozen, but bound water is almost unfrozen). Period C: Maximum ice crystal formation band lower limit to freezing storage temperature (from the state where free water is almost completely frozen, freezing of bound water proceeds,
Until the required freezing temperature is reached).

Embodiment 4 FIG. 12 is an explanatory diagram showing a method of freezing fresh food or the like according to Embodiment 4 of the present invention in a relationship between temperature and time, and shows an example in a case where a supercooled state occurs. The freezing process is almost the same as in the third embodiment, except that the periods A, B, and C are as follows. Period A: From the refrigeration temperature to the breaking point in the supercooled state. Period B: from the breaking point in the supercooled state to the upper and lower limits of the maximum ice crystal formation zone. Period C: Maximum ice crystal formation band lower limit to freezing storage temperature (from the state where free water is almost completely frozen, freezing of bound water proceeds,
Until the required freezing temperature is reached).

The range of the maximum ice crystal formation zone shown in the present embodiment and the above-described third embodiment varies in accordance with the type of the object to be frozen, but is basically the same. Further, the frequency and the irradiation period of the electromagnetic wave may be appropriately changed depending on the type of the object to be frozen or the cryoprotectant.

Embodiment 5 FIG. 13 is a diagram illustrating a method for freezing fresh food or the like according to Embodiment 5 of the present invention, and shows an example of a configuration in which a fish is used as the frozen object 7 and the surface of the frozen object 7 is covered with a sheet. In the present embodiment, sheet 1
6 has a two-layer structure of a resin film sheet 21 and a porous film sheet 22 with a cryoprotective substance 15 interposed therebetween, and also freezes between the frozen object 7 and the porous film sheet 22. The protective substance 15 is interposed. As described above, the frozen object 7 is covered with the sheet 16 with the cryoprotective substance 15 interposed therebetween, and the frozen object 7 is irradiated with the electromagnetic wave, and cooled with energy larger than the energy for heating the frozen object 7 by the electromagnetic wave irradiation. Then, by freezing the body 7 to be frozen, the progress of freezing (freezing rate) between the surface and the inside of the body to be frozen can be made uniform. Also,
The frozen object surface can be easily covered with the cryoprotectant 15.

Although the two-layer sheet shown in the present embodiment is not particularly limited, if a porous sheet 22 is used on the side in contact with the body 7 to be frozen, for example, the movement of moisture can be smoothly performed. . As the sheet, an insulating film such as polyethylene or polyvinylidene chloride may be used. In order to make the film porous, a film such as a foamed polyethylene sheet may be used. If the sheet 16 is brought into close contact with the body 7 to be frozen, it is not necessary to provide the cryoprotective substance 15 between the sheet 16 and the body 7 to be frozen. The cryoprotective substance 15 may be applied to one sheet 16 in advance, and the frozen object 7 may be covered as it is. Further, as the cryoprotective substance 15, the substance described in the second embodiment may be used.

Embodiment 6 FIG. Further, a method of thawing a high-quality frozen object will be described. In this embodiment, the frozen body is irradiated with the electromagnetic wave having the frequency shown in the first or second embodiment in place of a normal thawing method such as natural leaving in an atmosphere of 0 ° C. or more and microwave (microwave) heating. And thawed. In the above-mentioned frequency band, the difference between the relative permittivity of the liquid (water, solution) and the relative permittivity of the solid (ice) is small, or the relative permittivity of the solid is larger than the relative permittivity of the liquid. So you can equalize the progress of thawing,
Destruction of cell tissue can be suppressed, and the amount of drip can be reduced. Therefore, it is possible to prevent the deterioration of the quality of the taste and nutrition of fresh foods and the like, and to thaw it.

In the present embodiment, the method of freezing is not particularly limited. However, if the frozen body 7 frozen by the freezing method shown in the first to fifth embodiments is used, the taste of fresh food and the like can be further enhanced. , Prevent deterioration of nutrition and other quality,
Can be thawed.

Embodiment 7 FIG. FIG. 14 is a configuration diagram showing a refrigerating apparatus capable of realizing a method for refrigerating fresh food or the like according to Embodiment 7 of the present invention, wherein 1 is a high-frequency induction heater, and 2 is a high-frequency power source composed of a triode, a transistor, and the like. 3 is inductance, 4 is variable capacitance,
5 is an applied electrode, 6 is a matching device, 7 is a frozen object, 8 is a refrigerator, 9 is a heat exchanger for cooling, 11 is an electromagnetic wave shielding shield,
12 is a heat insulating shield, 13 is a freezer interior, 37 is an insulating stand, 42 is a temperature detecting unit, 25 is a cold air inlet, 26 is a cold air outlet, and 28 is a power meter.

In this refrigerating apparatus for fresh food or the like, the high-frequency dielectric heater 1 is configured by connecting a high-frequency generation power supply 2, a matching device 6, and an application electrode 5 with conductors. For example, the matching unit 6 includes the inductance 3 and the variable capacitance 4 so that the resonance state can be maintained even if the impedance of the frozen object 7 changes. The atmosphere temperature in the freezer interior 13 is maintained at a low temperature by circulating the air cooled by the cooling heat exchanger 9 of the refrigerator 8, and the object to be frozen 7 is placed on the insulating stand 37, and for example, two When sandwiched between the application electrodes 5 formed of parallel plates, the object to be frozen 7 can be frozen while being irradiated with electromagnetic waves.

When the fluctuation of the impedance of the frozen object 7 is small, the variable capacitance 4 need not be used.
Any capacitance may be used.

The switching from the irradiation period A to the irradiation period B and from the irradiation period B to the irradiation period C described in the third or fourth embodiment can be performed, for example, by the temperature detector 42 and the surface temperature of the frozen object and the power meter 28. To SWR (standing wave ratio)
Can be read and judged. At the switching point, the frozen body 7
Since the dielectric properties of the SWR greatly change and the SWR drops sharply, the point can be determined by monitoring this and switching the irradiation period.

In particular, when the irradiation period is not controlled,
The temperature detector 42 and the power meter 28 may be omitted.

In this embodiment, a parallel plate electrode is shown as the application electrode 5, but the electrode shape is a non-parallel plate type,
The shape may be a lattice shape, a coil shape, a cylindrical shape, a roller shape, or the like. Further, it may be a mobile type. It is more preferable that the flexible member be capable of reducing the influence of the air layer between the electrode plates.

In this embodiment, the electromagnetic wave shielding shield 11 is provided in order to prevent the possibility of causing radio interference due to the change of the oscillation frequency, but it may be omitted when unnecessary.

In this embodiment, for example, 0.3 to 3 MHz
An example is shown in which high-frequency dielectric heating is performed using any one of a medium wave of z, a short wave of 3 to 30 MHz, and an ultrashort wave of 30 to 300 MHz.

Further, in the refrigerating apparatus for fresh food or the like according to the present embodiment, at least the high-frequency dielectric heater 1
And the application electrode 5, it is possible to irradiate the above-mentioned electromagnetic wave to the frozen body, and it is possible to make a thawing apparatus for fresh foods and the like.

Embodiment 8 FIG. FIG. 15 is a configuration diagram showing a refrigerating apparatus for fresh food or the like according to an eighth embodiment of the present invention, in which 1 is a high-frequency dielectric heater, 6 is a matching device,
7 is a frozen object, 8 is a refrigerator, 9 is a heat exchanger for cooling, 10
Is a compressor, 11 is an electromagnetic wave shielding shield, 12 is an adiabatic shield, 13 is inside a freezer, 31 is a high-frequency oscillator, 32 is a high-frequency amplifier, 33 is an antenna, 34 is an electromagnetic wave, 37
Is an insulating table, and 42 is a temperature detecting unit.

In this refrigerating apparatus, for example, 40.6
A high frequency of 8 MHz is generated by the high frequency oscillator 31, amplified by the high frequency amplifier 32, and the electromagnetic wave is radiated from the antenna 33 to the inside of the freezer 13 into the air. Is possible. Therefore, even inside the freezer 13 in which large frozen objects such as tuna and meat are stacked, it is possible to freeze while uniformly irradiating the electromagnetic waves 34.

The length of the antenna 33 is generally 1/4.
Since it is necessary to have a wavelength longer than the wavelength, for example, 1.5 m for a wavelength of 6 m of an electromagnetic wave of 50 MHz, which requires a space,
It is preferable to use one that can be miniaturized such as a helical antenna system. It may be a biconical antenna, a logarithmic spiral antenna, a logarithmic periodic antenna, a dipole antenna, a loop antenna, a parabolic antenna, a long conducting wire antenna, or the like. Further, a microstrip array system, particularly a so-called ceramic antenna in which an antenna is laminated on a high dielectric ceramic in a plane, is suitable for miniaturization and flattening.

Embodiment 9 FIG. FIG. 16 is a configuration diagram showing a refrigerating apparatus for fresh food or the like according to a ninth embodiment of the present invention. In the figure, 6 is a matching box, 7 is a frozen object, 8 is a refrigerator, and 9 is heat exchange for cooling. 12. Insulation shield, 12;
56 is a freezer, 15 is a freeze protection substance, 16 is an insulating sheet, 25 is a cool air inlet, 26 is a cool air outlet, 27 is a ventilation hole, 31 is a high frequency oscillator, 32 is a high frequency amplifier, 34
Is an electromagnetic wave, 36 is a TEM cell, 37 is an insulating base, 38 is an outer rectangular conductor, 39 is a center conductor plate, and 41 is a coaxial termination load.

In this refrigerating apparatus, since the TEM cell 36 composed of, for example, the outer rectangular conductor 38, the center conductor plate 39, the coaxial terminal load 41, and the matching unit 6 is provided, the high-frequency electric signal is converted into a strong electric field electromagnetic wave. Thus, the object to be frozen 7 can be irradiated, and an electromagnetic wave of a strong electric field can be generated without leaking to the outside, so that the electromagnetic wave shield 11 can be omitted.
Therefore, the device configuration can be simplified.

The matching device 6 in the TEM cell 36 can be omitted as appropriate.

A normal TEM cell has a length of less than に wavelength so as not to generate a standing wave, but it is more preferable to design the TEM cell to have a length of about ４ wavelength to generate a standing wave.

Further, in the apparatus for refrigerating fresh food and the like in the present embodiment, if at least the high-frequency oscillator 31 and the TEM cell 36 are provided, the frozen body can be irradiated with the electromagnetic wave and a device for thawing fresh food and the like can be obtained. .

Further, the electromagnetic waves used in the first to ninth embodiments may be composed of only the specific frequency component, or may be broad including at least the specific frequency component.

[0069]

EXAMPLE Using the apparatus for freezing fresh food or the like described in the seventh embodiment, the object to be frozen is frozen and thawed by the method for freezing a fresh food or the like described in the first to fifth embodiments and the quality is reduced. The frozen body was thawed by the method for thawing fresh food or the like shown in the sixth embodiment using the apparatus for thawing fresh food or the like shown in the seventh or ninth embodiment and the fresh food or the like shown in the sixth embodiment to evaluate the quality. The evaluated examples are shown below.

Embodiment 1 Using the refrigeration apparatus of the seventh embodiment, a tuna cut was used as the body 7 to be frozen, and the temperature of the surface and the center of the body to be frozen was measured. FIG. 17 is a refrigeration curve obtained according to Example 1 of the present invention. Tuna fillets of about 300 g and thickness of about 3 cm were used, and a polyethylene sheet 16 further containing a 10% aqueous sucrose solution.
Cover the tuna fillet with an oscillation frequency of 40.68 MHz
While controlling the inductance 3 and the capacitance 4 so that the SWR becomes 3 or less, the amplifier output is about 15 W (electric field is about 2000 V / m), and the surface temperature of the object to be frozen is about 5 ° C. The electromagnetic wave irradiation was started from the time when the temperature dropped to, and after the irradiation period B, cooling was performed while adjusting the amplifier output according to the load fluctuation. When the surface temperature of the object to be frozen exceeded (−15 ° C.), the irradiation of the electromagnetic wave was terminated, and the object to be frozen was frozen to a temperature of about −20 ° C.

Embodiment 2 FIG. The electromagnetic wave irradiation was performed only during the period A (in a state where free water is not frozen; until the maximum ice crystal formation band is reached) described in the third embodiment. Except for the electromagnetic wave irradiation period, other conditions are the same as those in the first embodiment.

Embodiment 3 FIG. The electromagnetic wave irradiation was performed only during the period B (freezing of free water is in progress; the maximum ice crystal formation band) described in the third embodiment. Except for the electromagnetic wave irradiation period, other conditions are the same as those in the first embodiment.

Embodiment 4 FIG. The electromagnetic wave irradiation was performed only during the period C (from the state where free water is frozen to the state where the bound water is almost unfrozen) described in the third embodiment. Except for the electromagnetic wave irradiation period, other conditions are the same as those in the first embodiment.

Embodiment 5 FIG. Electromagnetic wave irradiation was performed only in the periods A and C described in the third embodiment. Except for the electromagnetic wave irradiation period, other conditions are the same as those in the first embodiment.

Embodiment 6 FIG. Other conditions were the same as in Example 1 above, except that the tuna fillet was covered with a polyethylene sheet containing no cryoprotectant.

Comparative Example 1. Tuna cuts were covered with a polyethylene sheet containing a 10% aqueous sucrose solution and frozen without irradiation with electromagnetic waves. Other conditions are the same as those in the first embodiment except that the electromagnetic wave irradiation is not performed.

Comparative Example 2 The tuna fillet was covered with a polyethylene sheet containing no cryoprotectant, and frozen without irradiation with electromagnetic waves. Other conditions are the same as in the first embodiment.

In Examples 1 to 6 and Comparative Examples 1 and 2, after the thawing, the amount of drip of the tuna fillet,
The texture was evaluated. The amount of drip was measured after 24 hours from the start of freezing and after natural thawing in a dark place at about 10 ° C. The results are as shown in Table 1. In all of Examples 1 to 6, the trip amount was smaller than in Comparative Examples 1 and 2 in which the electromagnetic wave was not irradiated, and good results were obtained. Further, Example 1 in which the fillet of the tuna was covered with a polyethylene sheet containing a 10% aqueous sucrose solution and irradiated with electromagnetic waves during all of the periods A to C described above had the least amount of drip, and good results were obtained. Also, it can be seen that the drip amount of Example 1 covered with the polyethylene sheet to which 10% sucrose was added was smaller than that of Example 6 covered with the polyethylene sheet without addition.

[0079]

[Table 1]

Embodiment 7 FIG. In the same manner as in Example 1, the electromagnetic wave irradiation was performed at an oscillation frequency of 13.56 MHz. Except for the electromagnetic wave frequency, other conditions are the same as those in the first embodiment.

Embodiment 8 FIG. Electromagnetic wave irradiation was performed at an oscillation frequency of 27.12 MHz in the same manner as in Example 1 above. Except for the electromagnetic wave frequency, other conditions are the same as those in the seventh embodiment.

Embodiment 9 FIG. In the same manner as in Example 1 above, irradiation with electromagnetic waves was performed at an oscillation frequency of 100 MHz. Except for the electromagnetic wave frequency, other conditions are the same as those in the seventh embodiment.

Embodiment 10 FIG. As in Example 1 above,
The oscillation frequency was 300 MHz, and the electromagnetic wave irradiation was performed. Except for the electromagnetic wave frequency, other conditions are the same as those in the seventh embodiment.

Comparative Example 3 Electromagnetic wave irradiation was performed using a magnetron having an oscillation frequency of 2.45 GHz. Except for the electromagnetic wave frequency and the electromagnetic wave generating means, other conditions are the same as those in the seventh embodiment. FIG. 18 shows a freezing curve of Comparative Example 3. When the amplifier output is about 15 W (electric field is about 30 V / m), electromagnetic wave irradiation is started when the surface temperature of the frozen object drops to about 5 ° C. After the irradiation period B, the amplifier output is adjusted according to the load fluctuation While cooling. When the surface temperature of the frozen object exceeds (−15 ° C.), the electromagnetic wave irradiation is terminated,
The object to be frozen was frozen to a center temperature of about −20 ° C.

Comparative Example 4 In the same manner as in Comparative Example 3, irradiation with electromagnetic waves was performed at an oscillation frequency of 2.45 GHz and an amplifier output of about 15 W (electric field of about 30 V / m). Electromagnetic wave irradiation was started when the temperature of the frozen object dropped to about 5 ° C., and the irradiation period ended only with A.

In the freezing methods of Examples 7 to 10 and Comparative Examples 3 and 4, after thawing, the amount of drip, shape loss and texture of the tuna cut were evaluated. The amount of drip was measured by thawing naturally in a dark place at about 10 ° C. after 24 hours from the start of freezing. The results are as shown in Table 2. Electromagnetic wave frequency 4
Although the amount of drip is increased as compared with Example 1 in which the frequency is 0.68 MHz, it is understood that the effect of reducing the amount of drip is smaller than that of the microwave irradiation of Comparative Examples 3 and 4.

[0087]

[Table 2]

Further, from the refrigeration curve of Example 1 shown in FIG. 17 and the refrigeration curve of Comparative Example 3 shown in FIG. 18, the upper and lower limits of the maximum ice crystal formation zone between the surface and the inside of the object to be frozen were determined. Time difference, that is, the shift of the effective freezing period in the figure 2
1a and 21b were compared. Further, the freezing rate when the surface temperature of the frozen object 7 reached the lower limit of the maximum ice crystal formation zone (D in the figure) was estimated and compared. Table 3 shows the results. Comparative Example 3
In Example 1, as compared with the case where microwave irradiation of
20b becomes shorter, and the difference in the freezing rate between the surface and the center is small, that is, the freezing progress state is uniform.

[0089]

[Table 3]

Embodiment 11 FIG. Tuna fillet (weight about 30
0 g, thickness of about 3 cm) was placed in the refrigeration apparatus of Embodiment 7 without covering with a sheet, and the transmission frequency was 40.68M.
Hz, inductance 3 and capacitance 4
Is adjusted so that the SWR becomes 3 or less, and the output of the amplifier is about 15 W (electric field is about 2000 V / m).
Then, the electromagnetic wave irradiation was started when the surface temperature of the frozen object dropped to about 5 ° C. After the irradiation period B, cooling was performed while adjusting the amplifier output according to the load fluctuation. When the surface temperature of the object to be frozen exceeded (−15 ° C.), the irradiation of the electromagnetic wave was terminated, and the object to be frozen was frozen to a temperature of about −20 ° C.

Embodiment 12 FIG. In the same manner as in Example 11, irradiation with electromagnetic waves was performed at an oscillation frequency of 13.56 MHz. Except for the electromagnetic wave frequency, other conditions are the same as those in the first embodiment.
Same as 1.

Embodiment 13 FIG. Electromagnetic wave irradiation was performed at an oscillation frequency of 27.12 MHz in the same manner as in Example 11 above. Except for the electromagnetic wave frequency, other conditions are the same as those in the first embodiment.
Same as 1.

Embodiment 14 FIG. Electromagnetic wave irradiation was performed at an oscillation frequency of 100 MHz in the same manner as in Example 11 above.
Except for the electromagnetic wave frequency, other conditions are the same as those in the eleventh embodiment.

Embodiment 15 FIG. Electromagnetic wave irradiation was performed at an oscillation frequency of 300 MHz in the same manner as in Example 11 above.
Except for the electromagnetic wave frequency, other conditions are the same as those in the eleventh embodiment.

Comparative Example 5 Electromagnetic wave irradiation was performed using a magnetron having an oscillation frequency of 2.45 GHz. Except for the electromagnetic wave frequency and the electromagnetic wave generation means, other conditions are the same as those in the eleventh embodiment. Approximately 15 W of amplifier output (approx.
(V / m), the electromagnetic wave irradiation is started when the surface temperature of the frozen object drops to about 5 ° C. After the irradiation period B, cooling is performed while adjusting the amplifier output according to the load fluctuation. When the surface temperature of the object to be frozen exceeded (−15 ° C.), the irradiation of the electromagnetic wave was terminated, and the object to be frozen was frozen to a temperature of about −20 ° C.

Comparative Example 6 In the same manner as in Comparative Example 5, irradiation with electromagnetic waves was performed at an oscillation frequency of 2.45 GHz and an amplifier output of about 15 W (electric field of about 30 V / m). Electromagnetic wave irradiation was started when the temperature of the frozen object dropped to about 5 ° C., and the irradiation period ended only with A.

Comparative Example 7 Frozen without irradiation with electromagnetic waves. Other than excluding no electromagnetic radiation, the other conditions are:
This is the same as Embodiment 11 described above.

Examples 11 to 15 and Comparative Example 7
After thawing, the amount of drip, shape loss and texture of the tuna fillet were evaluated. The amount of drip was measured by thawing naturally in a dark place at about 10 ° C. after 24 hours from the start of freezing. The results are as shown in Table 4, and in each of Examples 11 to 15, better results were obtained than Comparative Examples 5 and 6 irradiated with microwaves and Comparative Example 7 not irradiated with electromagnetic waves.
However, the amount of drip is greater than that of Example 1 in which the same is covered with a polyethylene sheet to which 10% sucrose has been added, and the amount of drip is increased, and it is more preferable to use both the electromagnetic wave irradiation and the cryoprotectant. I understand.

[0099]

[Table 4]

Embodiment 16 FIG. Approximately 200 g as frozen body
(20 g to 40 g per piece) of taro, impregnated with aqueous solutions of various cryoprotectants, at a frequency of 40.68 MH
Those frozen while irradiating them with the electromagnetic wave of z at an amplifier output of about 10 W were thawed in the same manner as in Example 1 to evaluate the state and texture. In addition, those not irradiated with electromagnetic waves and those not using a cryoprotectant were also evaluated. Table 5 shows the results. It has been found that when a cryoprotectant is used, irradiation with electromagnetic waves has a remarkable effect. In addition, it was found that those using a cryoprotectant were effective even without irradiation with electromagnetic waves.

[0101]

[Table 5]

Embodiment 16 FIG. Approximately 300 g of tuna fillets were frozen in the same manner as in Example 1 and stored for 24 hours, after which a frequency of 40.68 MHz and an amplifier output of approximately 200 W were used.
Then, electromagnetic wave heating was performed until the surface temperature of the object to be frozen reached about -20 ° C to 0 ° C, and then it was naturally thawed in a dark place at about 10 ° C.

Embodiment 17 FIG. Approximately 300 g of tuna fillets were frozen in the same manner as in Example 1 and stored for 24 hours, after which a frequency of 13.56 MHz and an amplifier output of approximately 500 W were used.
Then, electromagnetic wave heating was performed until the surface temperature of the object to be frozen reached about -20 ° C to 0 ° C, and then it was naturally thawed in a dark place at about 10 ° C.

Embodiment 18 FIG. Approximately 300 g of tuna fillets were frozen in the same manner as in Example 1 and stored for 24 hours, after which a frequency of 27.12 MHz and an amplifier output of approximately 500 W were used.
Then, electromagnetic wave heating was performed until the surface temperature of the object to be frozen reached about -20 ° C to 0 ° C, and then it was naturally thawed in a dark place at about 10 ° C.

Embodiment 19 FIG. Approximately 300 g of tuna fillets were frozen in the same manner as in Example 1 and stored for 24 hours. Then, at a frequency of 100 MHz and an amplifier output of approximately 500 W,
Electromagnetic wave heating was performed until the surface temperature of the object to be frozen reached about −20 ° C. to 0 ° C., and then it was naturally thawed in a dark place at about 10 ° C.

Embodiment 20 FIG. Approximately 300 g of tuna fillet was frozen in the same manner as in Example 1 and stored for 24 hours. Then, at a frequency of 300 MHz and an amplifier output of approximately 500 W,
Electromagnetic wave heating was performed until the surface temperature of the object to be frozen reached about −20 ° C. to 0 ° C., and then it was naturally thawed in a dark place at about 10 ° C.

Comparative Example 8 Approximately 300 g of tuna fillets were frozen in the same manner as in Example 1 and stored for 24 hours, after which a frequency of 2.45 GHz and an amplifier output of approximately 500 W were used.
Then, the surface of the object to be frozen was heated by electromagnetic waves until the surface temperature reached about -20 ° C to 0 ° C, and then naturally thawed in the refrigerator.

Comparative Example 9 Approximately 300 g of tuna fillets were frozen in the same manner as in Example 1 above, stored for 24 hours, and then naturally thawed in a dark place at approximately 10 ° C.

The drip amount, shape loss and texture of the tuna cuts defrosted in Examples 16 to 20 and Comparative Example 8 were evaluated. Table 6 shows the results. It was found that there was a remarkable effect when thawing by irradiating an electromagnetic wave having a frequency of 40.68 MHz. 13.56 MHz, 27.12 MH
When microwaves are irradiated with electromagnetic waves having a frequency of z, 100 MHz, or 300 MHz and thawed, microwaves (2.45 GHz) can be used.
z) The amount of drip is reduced by heating. There is not much difference from natural thawing, but it has the effect of thawing faster than natural thawing.

[0110]

[Table 6]

In Examples 1 to 16, tuna fillets and taro were used as the frozen object, but a more remarkable difference can be expected if the frozen object is large. The body to be frozen may be a cell tissue body such as pork or vegetables, or a body using sugars such as fresh cream or fresh confectionery such as anko. Especially PE
Cryoprotective substances such as G and glycerin are suitable for cryopreservation of medical uses such as sperm, blood and organs.

The appropriate frequency of the radiated electromagnetic wave is
Since the temperature fluctuates slightly depending on the temperature of the object to be frozen or impurities such as salt and oil contained in the object to be frozen, it is desirable to select an optimum frequency according to the object to be frozen.

[0113]

Since the present invention is configured as described above, it has the following effects. A cryoprotective substance consisting of a dielectric material is coated on the surface of the frozen object, or added to the inside, and the frozen object is irradiated with electromagnetic waves,
Since the object to be frozen is cooled by energy larger than the energy absorbed by the object to be frozen by the electromagnetic wave irradiation, and the object to be frozen is frozen, freeze concentration can be suppressed and the amount of drip can be reduced. Can hold.

Further, since the electromagnetic wave is provided with a frequency at which the relative dielectric loss factor of the solid of the aqueous solution containing the cryoprotectant is higher than the relative dielectric loss factor of the aqueous solution, the cryoprotective material is applied to the surface of the frozen object. If coated or added to the inside, and irradiating the electromagnetic wave of the specific frequency band, not only can the ice crystal be miniaturized, but also the freezing progress can be uniform,
Freeze concentration can be suppressed, drip amount can be reduced, and taste and nutrition can be maintained at a higher level.

Since the electromagnetic wave has a frequency in the range of 10 MHz to 300 MHz, the electromagnetic wave not only has an effect of suppressing ice growth like a microwave but also has an effect on the liquid phase portion of the object to be frozen. Because there is no biased dielectric heating,
The state of freezing progress can be made uniform over the surface and inside of the frozen object and over the entire frozen object, and freezing can be performed without promoting freeze concentration.

Further, since the electromagnetic wave irradiating means is an antenna, it is possible to irradiate the electromagnetic wave over a wide range, and even if the frozen objects are large or stacked, the frozen objects can be uniformly heated. it can.

Further, since the means for irradiating the electromagnetic wave is a TEM cell, it is possible to safely perform dielectric heating without leaking the electromagnetic wave of a strong electric field to the outside.

The cryoprotectant or an aqueous solution containing the cryoprotectant may be used in a frequency band in which the relative dielectric loss factor at the frozen storage temperature of the frozen object is higher than the relative dielectric loss factor at the freezing point of the frozen object. As a result, the progress of freezing can be made uniform, freezing and concentration can be suppressed, and the amount of drip can be reduced.

Further, since the cryoprotectant contains any one of saccharides, glycoproteins, glycolipids, polyhydric alcohols, polymers of polyhydric alcohols, and lipids, it can be easily added to foods and the like. Alternatively, it can be coated.

[0120] Cryoprotective substances include glucose, fructose, sucrose, trehalose, maltose, lactose,
Since it contains any of fructooligosaccharides, glycoproteins, glycolipids, ethylene glycol, glycerin, and glycerides, or any of these polymers, it can be easily added to or coated on foods and the like.

Further, since the coating is performed with a sheet coated with or interposed with a cryoprotectant, the surface of the frozen object can be easily covered with the cryoprotectant.

In addition, since the irradiation of the electromagnetic wave is performed before the frozen object reaches the freezing point and until it passes the lower limit of the maximum ice crystal formation zone, the freeze concentration can be suppressed to a higher degree, and the drip amount can be reduced. .

Further, the relative permittivity of the aqueous solution containing the cryoprotectant substantially matches the relative permittivity of the solid of the aqueous solution, or the relative permittivity of the solid is lower than the relative permittivity of the aqueous solution. Higher frequency, or 10MHz to 300MHz
Since the frozen body is thawed using any frequency in the range, the freeze concentration can be suppressed to a higher degree, and the thaw can be thawed with a reduced drip amount.

Further, the relative permittivity of the aqueous solution containing the cryoprotectant substantially matches the relative permittivity of the solid of the aqueous solution, or the relative permittivity of the solid is lower than the relative permittivity of the aqueous solution. Higher frequency, or 10MHz to 300MHz
A means for generating an electromagnetic wave of any frequency in the range of, or an electromagnetic wave generating means such as an antenna or a TEM cell; a means for irradiating the object to be frozen such as fresh food with a heating means; Means for cooling the body to be frozen by cooling with energy larger than the energy absorbed by the frozen body, so that ice crystal growth can be suppressed and freezing can be performed, reducing the amount of drip and reducing shape loss. It is possible to maintain the freshness of the object to be frozen.

Further, the relative permittivity of the aqueous solution containing the cryoprotectant substantially matches the relative permittivity of the solid of the aqueous solution, or the relative permittivity of the solid is lower than the relative permittivity of the aqueous solution. Higher frequency, or 10MHz to 300MHz
Means for generating an electromagnetic wave of any frequency in the range of, or an electromagnetic wave generating means such as an antenna or a TEM cell, and a means for irradiating the electromagnetic wave to a frozen body such as fresh food and heating the same, so that the drip amount Lowers the shape and prevents thawing.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a relative dielectric constant of water and ice and a relationship between a relative dielectric loss factor and a frequency according to the first embodiment of the present invention.

FIG. 2 illustrates a second embodiment of the present invention.
It is a characteristic view which shows the relationship between the relative dielectric loss factor in 40.68 MHz of 1N salt solution, and temperature.

FIG. 3 is a characteristic diagram illustrating the relationship between the relative dielectric loss factor and the temperature at 40.68 MHz of a 10% aqueous sucrose solution for explaining Embodiment 2 of the present invention.

FIG. 4 is a characteristic diagram illustrating the relationship between the relative dielectric loss factor and the temperature at 40.68 MHz of a 30% aqueous polyethylene glycol solution for explaining Embodiment 2 of the present invention.

FIG. 5 is a characteristic diagram illustrating the relationship between the relative dielectric loss factor and the temperature at 13.56 MHz of econa oil for explaining Embodiment 2 of the present invention.

FIG. 6 is a characteristic diagram illustrating a relationship between a specific dielectric loss factor (ε _r ) of a liquid and a solid of a sucrose aqueous solution having different concentrations and a frequency, which explains Embodiment 2 of the present invention.

7 is a characteristic diagram showing the relationship between the ratio and the frequency of the "epsilon _r of the solid for" epsilon _r of the liquid (freezing point) sucrose solution for explaining the second embodiment of the present invention.

8 is a characteristic diagram showing the relationship between the ratio and the frequency of the "epsilon _r of the solid for" epsilon _r of the liquid (freezing point) with a 5% aqueous trehalose solution for explaining the second embodiment of the present invention.

9 is a characteristic diagram showing the relationship between the ratio and the frequency of the "epsilon _r of the solid for" epsilon _r of the liquid (freezing point) with a 10% glucose solution for explaining the second embodiment of the present invention.

FIG. 10 is a view illustrating 30% of Embodiment 2 of the present invention;
In PEG600 solution is a characteristic diagram showing the relationship between the ratio and the frequency of the liquid "solid epsilon _r for" epsilon _r of (freezing point).

FIG. 11 is an explanatory diagram showing a method of freezing fresh food and the like according to Embodiment 3 of the present invention in relation to temperature and time.

FIG. 12 is an explanatory diagram showing a method of freezing fresh food and the like according to a fourth embodiment of the present invention in terms of a relationship between temperature and time.

FIG. 13 is a diagram showing a method for freezing fresh food and the like according to Embodiment 5 of the present invention.

FIG. 14 is a configuration diagram showing an apparatus for freezing fresh food or the like according to Embodiment 7 of the present invention.

FIG. 15 is a configuration diagram showing an apparatus for freezing fresh food or the like according to Embodiment 8 of the present invention.

FIG. 16 is a configuration diagram showing an apparatus for freezing fresh food or the like according to Embodiment 9 of the present invention.

FIG. 17 is a graph showing the relationship between the freezing curve and the freezing rate and time according to the first embodiment of the present invention.

FIG. 18 is a graph showing the relationship between the freezing curve and the freezing rate and time according to Comparative Example 1 of the present invention.

[Explanation of symbols]

1 high frequency induction heater, 2 high frequency generation power supply, 3 inductance, 4 capacitance, 5 applied electrode, 6
Matching device, 7 body to be frozen, 8 refrigerator, 9 heat exchanger for cooling, 10 compressor, 11 electromagnetic wave shielding shield, 12
Insulation shield, 13 Inside of freezer, 15 Freezing protection substance, 16 sheets, 21 Resin film sheet, 22
Porous film sheet, 31 high frequency oscillator, 32 high frequency amplifier, 33 antenna, 34 electromagnetic wave, 36
TEM cell, 37 insulation base, 38 outer rectangular conductor, 39
Center conductor plate, 40 coaxial connector, 41 coaxial termination load

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norio Mitsuda 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Koji Kajiyama 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F term (reference) in Mitsubishi Electric Corporation 3L045 AA00 BA03 BA05 CA03 DA02 EA01 KA09 PA01 PA04 PA06 4B022 LA06 LB01 LJ02 LJ04 LN10 LQ07 LT02

Claims (13)

[Claims] 1. A cryoprotectant made of a dielectric material is coated on or added to the surface of an object to be frozen, and the object to be frozen is irradiated with electromagnetic waves. A refrigeration method comprising cooling the object to be frozen by cooling with an energy greater than the energy to be frozen. 2. The refrigeration method according to claim 1, wherein the electromagnetic wave has a frequency at which the relative dielectric loss factor of the solid of the aqueous solution containing the cryoprotectant exceeds the relative dielectric loss factor of the aqueous solution. 3. The electromagnetic wave according to claim 1, wherein the electromagnetic wave has a frequency in a range of 10 MHz to 300 MHz.
The refrigeration method according to 1. 4. The refrigeration method according to claim 1, wherein the electromagnetic wave irradiation means is an antenna. 5. The refrigeration method according to claim 1, wherein the electromagnetic wave irradiation means is a TEM cell. 6. The cryoprotectant or the aqueous solution containing the cryoprotectant may be used in a frequency band in which the relative dielectric loss factor at the frozen storage temperature of the frozen object is higher than the relative dielectric loss factor at the freezing point of the frozen object. The refrigeration method according to claim 1, comprising: 7. The cryoprotectant according to claim 1, wherein the cryoprotectant contains at least one of saccharides, glycoproteins, glycolipids, polyhydric alcohols, polymers of polyhydric alcohols, and lipids. Freezing method. 8. The cryoprotectant is at least one of glucose, fructose, sucrose, trehalose, maltose, lactose, fructooligosaccharide, glycoprotein, glycolipid, ethylene glycol, glycerin, and glyceride;
Alternatively, the refrigeration method according to claim 7, comprising any one of these polymers. 9. The refrigeration method according to claim 1, wherein the coating is performed with a sheet on which a cryoprotectant is applied or interposed. 10. The refrigeration method according to claim 1, wherein the irradiation of the electromagnetic wave is performed before the object to be frozen reaches the freezing point and until the lower limit of the maximum ice crystal formation zone is exceeded. 11. A thawing method characterized by thawing a frozen body using the electromagnetic wave of the frequency according to claim 2 or 3. 12. A means for generating an electromagnetic wave having a frequency according to claim 2 or 3, or an electromagnetic wave generating means according to claim 4 or 5, a means for irradiating the object to be frozen with said electromagnetic wave and heating said object. Means for cooling the object to be cooled by cooling with energy larger than the energy absorbed by the object to be frozen by heating. 13. A means for generating an electromagnetic wave having the frequency according to claim 2 or 3, or a means for generating an electromagnetic wave according to claim 4 or 5, and a means for irradiating the refrigerator with the electromagnetic wave and heating it. A thawing device characterized by the following.