JPWO2019239994A1 - Frozen sushi set - Google Patents

Abstract

The frozen sushi pack (500) is thawed by dielectric heating treatment with a high frequency electric field of HF wave or VHF wave. The frozen sushi pack (500) includes a container (530) and a plurality of sushi (510.520) arranged in the container (530). Sushi (510.520) has a rice sushi portion (512.522) and a material portion (511.521). The plurality of sushi in the container (530) are at least two types having different heights (that is, the relatively tall first sushi (510) and the relatively short second sushi (520). )).

Description

The present invention relates to a frozen sushi set thawed by dielectric heating with a high frequency electric field of HF or VHF waves.

In recent years, innovations in freezing technology such as freezing and refrigeration management and freshness preservation technology have brought about innovations in food distribution. This technological innovation and the transition to a global society have led to a great deal of interest in food diversification and food. Along with this, the demand for high-quality food has increased, and eating out, conveyor belt sushi, etc. that sell freshness have been introduced.

In order to meet the high interest and demand of consumers for food, it is desired to develop the thawing technology along with the progress of freezing and refrigerating technology.

For example, Patent Document 1 discloses a high-frequency heating device used for thawing frozen sushi. This high-frequency heating device uses microwaves and places frozen sushi according to the distribution of microwaves to reduce uneven heating. In addition, frozen sushi is placed on the turntable, and the rotation of the turntable reduces the variation in heating between multiple sushi.

Further, the frozen sushi disclosed in Patent Document 2 is devised to reduce uneven heating by arranging the sushi according to the distribution of microwaves when heated in a microwave oven.

Further, in Patent Document 3, a container (magnetic shield material) containing water is arranged above the sushi container, and the temperature of sushi at the time of thawing is adjusted by utilizing the fact that water is heated earlier than ice. A method of thawing frozen sushi to be adjusted is disclosed.

Japanese Unexamined Patent Publication No. 10-210960 Japanese Unexamined Patent Publication No. 10-290673 Japanese Unexamined Patent Publication No. 10-56995

Advances in freezing and refrigerating technology have made it possible to store food for long periods of time, but the final taste of food is often determined by the final thawing technology. However, the current thawing technology has problems such as overheating and deterioration of texture. In addition, some foods are not suitable for thawing, and the food options are relatively narrow, which does not fully satisfy the appetite of consumers. As described above, the thawing technology lags behind the progress of freezing and refrigerating technology, and the current situation is that satisfactory technology is not widely used.

In particular, when a sushi set composed of frozen sushi of a plurality of types of ingredients is thawed by dielectric heating, there is a problem that the temperature rise becomes uneven depending on the type of ingredients and the sushi cannot be thawed uniformly. For example, squid, scallops, and other ingredients with a high water content are difficult to warm, while salmon roe, toro, and mackerel, which have a low water content, tend to warm up. Therefore, although the squid is still frozen, there are problems such as burning of Toro.

Therefore, the present invention provides a frozen sushi set that can maintain a good texture and quality when thawed by dielectric heating and thawing.

The frozen sushi set according to one aspect of the present invention is thawed by dielectric heating treatment with a high frequency electric field of HF wave or VHF wave. This frozen sushi set includes a container and a plurality of sushi arranged in the container. In this frozen sushi set, the sushi has a sushi portion and a material portion arranged on the sushi portion. Further, the plurality of sushi pieces are composed of at least two types of sushi having different heights.

In the frozen sushi set according to one aspect of the present invention, the plurality of sushi pieces are a first group having a height higher than a predetermined value and a second group having a height equal to or lower than the predetermined value. The sushi classified into the first group and the sushi classified into the second group may be alternately arranged in the container.

In the frozen sushi set according to one aspect of the present invention, the plurality of sushi pieces are a first group having a height higher than a predetermined value and a second group having a height equal to or lower than the predetermined value. The sushi classified into the first group may be arranged in the central portion of the container.

In the frozen sushi set according to one aspect of the present invention, the plurality of sushi pieces are a first group having a height higher than a predetermined value and a second group having a height equal to or lower than the predetermined value. The sushi classified into the second group may be arranged at the corner of the container.

In the frozen sushi set according to one aspect of the present invention, the height dm of the sushi having the lowest height among the plurality of sushi is 60% or more of the height dmax of the sushi having the highest height. You may.

In the frozen sushi set according to one aspect of the present invention, the height of each of the plurality of sushi is d, the water ratio of each of the plurality of sushi is B, and in each sushi, with respect to the height d. Assuming that the ratio of the water content ratio B is C, the minimum value Cmin of the ratio C may be 60% or more of the maximum value Cmax of the ratio C.

In the frozen sushi set according to one aspect of the present invention, the height of each of the plurality of sushi is d, the mass density of each of the plurality of sushi is G, and in each sushi, with respect to the height d. Assuming that the ratio of the mass density G is H, the minimum value Hmin of the ratio H may be 60% or more of the maximum value Hmax of the ratio H.

In the frozen sushi set according to one aspect of the present invention, the plurality of sushi pieces are a first group having a height higher than a predetermined value and a second group having a height equal to or lower than the predetermined value. The water content per unit volume of the material portion of the sushi classified into the first group is the water content per unit volume of the material portion of the sushi classified into the second group. May be more than.

As described above, according to the frozen food according to one aspect of the present invention, it is possible to suppress the occurrence of uneven heating and overheating when thawed by dielectric heating treatment of HF wave or VHF wave by a high frequency electric field. The sushi set obtained by performing such a thawing treatment from the frozen sushi set according to one aspect of the present invention has a good texture and quality. Therefore, it is considered that it is possible to provide a sushi set with a higher degree of consumer satisfaction.

It is a schematic diagram which shows the appearance structure of the high frequency heating apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus shown in FIG. It is a figure which shows the circuit structure in the high frequency heating apparatus shown in FIG. It is a graph which shows the relationship between the height ratio of the thawed material (heated object) with respect to the distance between electrodes, and the energy ratio in each part of thawed material. (A) and (b) are schematic views showing the relationship between the height H of the object to be heated A and the distance D between the electrodes. It is a graph which shows the ratio of the voltage between electrodes when the height H of the object A to be thawed varies variously. It is a graph which shows the ratio of the voltage between electrodes when the height H of the object A to be thawed varies variously. It is a table which shows the evaluation result when the thawing process was performed by changing the distance D between electrodes in various objects A to be thawed. It is a schematic diagram which shows each space formed when the object A to be thawed is placed in the heating chamber of a high frequency heating apparatus. It is a schematic diagram which showed each space shown in FIG. 9 as an electric equivalent circuit by a capacitor. It is a graph which shows the change of the total current / thawed material current with respect to electrode area / thawed material bottom area (n) when high frequency voltage is applied to the high frequency heating apparatus shown in FIG. It is a graph which shows the change of the total current / thawed material current with respect to electrode area / thawed material bottom area (n) when high frequency voltage is applied to the high frequency heating apparatus shown in FIG. It is a table which shows the wiring loss ratio at the time of thawing processing of each food material in the high frequency heating apparatus with different electrode areas. It is a table which shows the total current / thawed product current when each food material is thawed in the high frequency heating device which has a different electrode area. It is a schematic diagram which shows the internal structure of the high frequency heating apparatus which concerns on 2nd Embodiment. It is a figure which shows the circuit structure in the high frequency heating apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the frozen food (frozen sushi) which concerns on 3rd Embodiment. It is a figure which shows the temperature rise by thawing of a VHF wave or an HF wave in an electric field when the water content of the upper layer part is larger than the water content of a lower layer part. It is a figure which shows the temperature rise by thawing of a VHF wave or an HF wave in an electric field when the water content of an upper layer part is smaller than the water content of a lower layer part. It is a figure which shows the water content (moisture ratio%) contained in the ingredient of various sushi which constitutes a sushi pack. It is a schematic diagram which shows another example of the frozen food which concerns on 3rd Embodiment. It is a schematic diagram which shows each process of the food manufacturing method which concerns on 4th Embodiment. It is a figure which shows the temperature change (freezing curve) at the time of rapid freezing and the time of slow freezing. It is a side schematic diagram which shows an example of the frozen sushi pack which concerns on 5th Embodiment. It is a side schematic diagram which shows another example of the frozen sushi pack which concerns on 5th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 5th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 5th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 5th and 6th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 5th and 6th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 5th and 6th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 5th Embodiment. It is a figure which shows the relationship between the total water content (g) contained in the material of each sushi which constitutes a frozen sushi pack, and the product of thawing time and thawing power (time × W). It is a side schematic diagram which shows the frozen sushi pack which concerns on the modification of 5th Embodiment. It is a side schematic diagram which shows the frozen sushi pack which concerns on the modification of 5th Embodiment. It is a side schematic diagram which shows the frozen sushi pack which concerns on the modification of 5th Embodiment. It is a schematic diagram for demonstrating the temperature unevenness which occurs due to the difference in the height of the object to be heated at the time of thawing. It is a side schematic diagram which shows an example of the frozen sushi pack which concerns on 6th Embodiment. It is a top view which shows the frozen sushi pack shown in FIG. 37. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 6th Embodiment. It is a schematic diagram which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 6th Embodiment. It is a schematic diagram for demonstrating the temperature unevenness which occurs inside the object to be heated at the time of thawing. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 6th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 6th Embodiment. It is a top view which shows the example of the arrangement of sushi in the frozen sushi pack which concerns on 6th Embodiment. It is a schematic diagram which shows the state of thawing the object to be heated of height d using the electrode of the distance D between electrodes. It is a circuit diagram which shows the electric equivalent circuit of the structure shown in FIG. 45. It is a graph which shows the relationship between the maximum height (cm) of sushi and an energy ratio. It is a schematic diagram which shows the relationship between the maximum height (dmax) and the minimum height (dmin) of sushi. It is a graph which shows the relationship between the height (cm) of sushi and the energy ratio.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of them will not be repeated.

[First Embodiment]
(Outline configuration of high frequency heating device)
In the present embodiment, as an example of the dielectric heating device of the present invention, the high frequency heating device 100 will be described as an example. The high-frequency heating device 100 is suitable for use in a small space where a large machine cannot enter, such as a retail store such as a convenience store, a kitchen such as a restaurant, and a kitchen at home.

First, the schematic configuration of the high-frequency heating device 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 shows the appearance of the high frequency heating device 100. FIG. 2 shows the internal configuration of the high frequency heating device 100.

As shown in FIG. 1, the high-frequency heating device 100 is mainly composed of a main body 101 and a reading unit 4 connected to the main body 101. In the present embodiment, the reading unit 4 has a function as a discriminating unit for discriminating the type, size, etc. of the object to be heated (object to be defrosted) A to be heated (or thawed) by using the high-frequency heating device 100. ing. The reading unit 4 is realized by, for example, a barcode reading device. The object to be heated A is, for example, a product (frozen food, refrigerated food) sold at convenience stores, supermarkets, and the like. A barcode B that can be read by the reading unit 4 is attached to the object A to be heated.

The high-frequency heating device 100 of the present embodiment applies a high-frequency electric field to the object to be heated A to perform thawing treatment, heat treatment, and the like of the object to be heated. The high frequency heating device 100 includes a heating chamber (thawing chamber) 9. The heating chamber 9 is formed of a metal housing.

As shown in FIG. 2, the heating chamber 9 is provided with an upper electrode 1a, a lower electrode 1b, a movable part (position changing mechanism) 8, a top plate 10, a bottom plate 11, a radiant heat sensor 21, and the like. .. The upper electrode 1a and the lower electrode 1b form an electrode plate of the high frequency heating device 100. The upper electrode 1a and the lower electrode 1b are arranged so as to be parallel to each other. The upper electrode 1a, the lower electrode 1b, the top plate 10, and the bottom plate 11 are all flat plates. The top plate 10 is arranged below the upper electrode 1a. The bottom plate 11 is arranged above the lower electrode 1b.

The upper electrode 1a is adhered and fixed to the upper surface of the top plate 10. Further, the upper electrode 1a is connected to the movable portion 8. The upper electrode 1a is supported upward in the heating chamber 9 by the movable portion 8.

The movable portion 8 includes parts such as a gear and a motor. These parts are connected to the control circuit 6 by wiring, and the upper electrode 1a and the top plate 10 can be moved in the vertical direction. As a result, the position of the upper electrode 1a can be changed according to the size of the object A to be heated during the heat treatment. That is, the distance between the upper electrode 1a and the lower electrode 1b can be changed. As described above, the movable portion 8 functions as a position changing mechanism (also referred to as a height changing mechanism) for changing the position (height) of the electrode plate (in the present embodiment, the upper electrode 1a).

The upper electrode 1a and the lower electrode 1b are connected to the voltage application unit 20 (specifically, the matching circuit 3) via wiring. As a result, a high-frequency electric field is applied between the upper electrode 1a and the lower electrode 1b.

The bottom plate 11 is fixed to the side wall of the heating chamber 9. Then, the lower electrode 1b is adhered and fixed to the lower surface of the bottom plate 11. As described above, in the present embodiment, the positions of the bottom plate 11 and the lower electrode 1b are fixed in the heating chamber 9.

When the object to be heated A is heated or thawed using the high-frequency heating device 100, the object to be heated A is placed on the bottom plate 11. Then, a high-frequency electric field is applied between the upper electrode 1a and the lower electrode 1b to perform dielectric heating and thawing due to the dielectric loss of the object A to be heated.

In the present embodiment, the height of the upper electrode 1a can be changed by moving the movable portion 8 connected to the upper electrode 1a up and down. Therefore, the distance between the upper electrode 1a and the lower electrode 1b can be changed according to the size of the object A to be heated placed on the bottom plate 11.

When the size of the object to be heated A is relatively small, the upper electrode 1a can be positioned downward so that the object A to be heated and the upper electrode 1a are close to each other, so that the object A to be heated can be efficiently placed. Can be heated. On the other hand, when the size of the object to be heated A is relatively large, the upper electrode 1a can be positioned upward so that the object to be heated A and the upper electrode 1a do not come into contact with each other. As a result, a relatively large object A to be heated can be efficiently heated.

The radiant heat sensor 21 is arranged on the side wall in the heating chamber 9. Specifically, it is arranged near the place where the object to be heated A is placed on the bottom plate 11 and outside the installation area of the upper electrode 1a and the lower electrode 1b. The radiant heat sensor 21 detects the surface temperature of the object A to be heated. The radiant heat sensor 21 is connected to the control circuit 6 in the voltage application unit 20. The detection result of the radiant heat sensor 21 is transmitted to the control circuit 6. In the present embodiment, the heated state (thawed state) of the object to be heated A can be identified by the radiant heat sensor 21.

Further, as shown in FIG. 2, the high-frequency heating device 100 has a voltage application unit 20, a control circuit (control unit) 6, a reading unit 4, an operation unit (input unit) 7, and a memory 5 outside the heating chamber 9. And so on. The voltage application unit 20 applies a high frequency voltage between the upper electrode 1a and the lower electrode 1b. The voltage application unit 20 has a high-frequency power supply 2, a matching circuit 3, and the like as main constituent members. The detailed configuration of the voltage application unit 20 will be described later.

The control circuit 6 is connected to each component in the high-frequency heating device 100 and controls these components. For example, the control circuit 6 is connected to the movable portion 8 and controls the operation of the movable portion 8.

Further, the control circuit 6 is connected to the high frequency power supply 2 and the matching circuit 3 via wiring in addition to the movable portion 8. The control circuit 6 can efficiently heat the object to be heated A by controlling the output of the high-frequency power supply 2 and the impedance of the matching circuit 3.

Further, the control circuit 6 is also connected to the reading unit 4 and the memory (storage unit) 5 via wiring. The control circuit 6 collates the information of the object to be heated A read by the reading unit 4 with the data stored in the memory 5 and sets the optimum control conditions for the object A to be heated. A can be heated efficiently.

The memory 5 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The memory 5 stores the operation program and setting data of the high-frequency heating device 100. Further, the memory 5 is connected to the control circuit 6 and temporarily stores the calculation result by the control circuit 6. Further, in the present embodiment, the memory 5 stores data of the type of the object to be heated A and the optimum control conditions for each.

The memory 5 stores, for example, the distance between the electrodes and the capacities of the variable capacitors 3a and 3b as control information determined based on the identification information of the object to be heated A obtained by the reading unit 4. Control information other than these may be stored in the memory 5. Other control information includes, for example, the output power of the high-frequency power supply 2, the driving time (heating time) of the high-frequency power supply 2, and the like.

The voltage application unit 20 and the memory 5 are arranged in the main body 101. On the other hand, the reading unit 4 is provided on the outside of the main body 101. The reading unit 4 is connected to the main body unit 101 (specifically, the control circuit 6) via wiring.

The reading unit 4 is a means capable of identifying what the heated object A looks like (for example, the type, size, weight, water content, etc. of the heated object A). The reading unit 4 is realized by, for example, a barcode reading device, an RF tag reading device, an image recognition device, or the like.

The operation unit 7 is arranged, for example, on the front side of the main body 101 (see FIG. 1). The operation unit 7 is provided with an operation button capable of inputting the type, size, weight, water content, heating time (thawing time), output power at the time of heating, and the like of the object A to be heated. By providing such an operation unit 7, in addition to the method of reading the barcode B of the object A to be heated by the reading unit 4, the user manually determines the type of the object A to be heated, the heating time (thawing time), and the like. And the output power at the time of heating can be set.

As described above, the high-frequency heating device 100 according to the present embodiment includes a reading unit 4 that reads the type, size, etc. of the object A to be heated, and control information when the object A to be heated and the object A to be heated are heated. It is provided with a memory 5 that stores the above-mentioned items in association with each other, and a control circuit 6 that changes the heating time, output power, and the like based on the control information corresponding to the object to be heated A determined by the reading unit 4.

Further, the high-frequency heating device 100 according to the present embodiment may include a weight sensor for measuring the weight of the object to be heated A as a configuration other than the above. The weight sensor is connected to the control circuit 6 in the voltage application unit 20, and information regarding the weight of the object A to be heated by the weight sensor is transmitted to the control circuit 6. According to this configuration, the control circuit 6 takes into consideration the weight information transmitted from the weight sensor in addition to the information regarding the type of the object to be heated A transmitted from the reading unit 4 and the operating unit 7, and the heating time. (Thaw time) and output power (output wattage) can be changed.

In the present embodiment, a configuration in which two electrodes (that is, an upper electrode 1a and a lower electrode 1b) arranged opposite to each other are arranged in the heating chamber 9 has been described as an example. However, in another aspect of the present invention, the two electrodes arranged facing each other may be arranged outside the heating chamber, respectively. Further, any one of the two electrodes (for example, the upper electrode and the lower electrode) may be a part of the housing of the heating chamber made of metal.

(Structure of voltage application part)
Subsequently, the configuration of the voltage application unit 20 that applies a voltage to each electrode in the heating chamber 9 will be described with reference to FIGS. 2 and 3. FIG. 3 is a circuit diagram showing a circuit configuration between the electrodes 1a and 1b and the high frequency power supply 2.

The voltage application unit 20 applies a high frequency voltage between the upper electrode 1a and the lower electrode 1b. The voltage application unit 20 has a high-frequency power supply 2, a matching circuit 3, and the like as main constituent members.

The high frequency power supply 2 transmits a voltage signal having a frequency in the band from HF to VHF. Here, the HF band refers to a frequency band within the range of 3 MHz or more and 30 MHz or less. The VHF band refers to a frequency band within the range of 30 MHz or more and 300 MHz or less. The voltage signal transmitted from the high frequency power supply 2 is amplified to a desired power by an amplifier (not shown). The amplified voltage signal is transmitted to the matching circuit 3.

As shown in FIG. 3, the matching circuit 3 includes variable capacitors (variable reactance elements) 3a and 3b, a coil 3c, and the like. As a result, the matching circuit 3 cancels out the reactance of the capacitor composed of the upper electrode 1a and the lower electrode 1b. Further, the matching circuit 3 can match the input impedance to the matching circuit 3 with the output impedance to the amplifier by adjusting the values of the variable capacitors 3a and 3b. As a result, a high-frequency electric field can be efficiently applied to the object A to be heated.

A coil 12 is arranged between the variable capacitor 3b of the matching circuit 3 and the upper electrode 1a. The coil 12 functions together with the matching circuit 3 as an inductor for impedance matching in the circuit of the high-frequency heating device 100.

The voltage signal subjected to impedance matching in the matching circuit 3 is supplied to a capacitor formed by the upper electrode 1a and the lower electrode 1b. As a result, a high-frequency electric field is generated between the upper electrode 1a and the lower electrode 1b. Then, the object to be heated A placed between the upper electrode 1a and the lower electrode 1b is dielectrically heated.

(Regarding the control of the distance between the upper electrode 1a and the lower electrode 1b)
Subsequently, the distance control between the upper electrode 1a and the lower electrode 1b will be described with reference to the drawings.

The high-frequency heating device 100 according to the present embodiment is suitable for thawing food in a retail store such as a home or a convenience store. In the high-frequency heating device 100, the distance D between the upper electrode 1a and the lower electrode 1b is set in consideration of the size, quantity, shape, etc. of the object A to be heated, which is assumed when used in a home or a retail store. It is set to be within the range of 3.0 cm or more and 27 cm or less. As a result, the user can easily and safely use the high frequency heating device 100.

Here, the relationship between the height H of the object to be heated A and the distance D between the electrodes will be described. FIG. 4 shows the relationship between the ratio of the height H of the object to be thawed (object to be heated) A to the distance D between the electrodes and the energy ratio in each part of the thawed material.

As shown in FIG. 5A, when the height H of the object to be thawed A is smaller than the distance D between the electrodes (that is, the gap (space) between the object to be thawed A and the upper electrode 1a is large). , The difference in energy applied to the parts having different heights in the object A to be thawed becomes smaller (see the frame part of the broken line shown in FIG. 4). On the other hand, as shown in FIG. 5B, the height H of the object to be thawed A is larger than the distance D between the electrodes (that is, the gap (space) between the object to be thawed A and the upper electrode 1a is small. ), The difference in energy applied to the parts having different heights in the object A to be thawed becomes large (see the frame part of the alternate long and short dash line shown in FIG. 4).

For example, the ratio of the height H of the object to be thawed (object to be heated) A to the distance D between the electrodes is 0.8 or less (that is, the height H of the object to be heated A is within 80% of the distance D between the electrodes). The energy ratio in each part of the object A to be thawed can be set to 0.4 or less (see FIG. 4). That is, the heating unevenness of the object A to be thawed can be suppressed to be relatively small.

However, if the gap (space) between the object to be thawed A and the upper electrode 1a becomes too large, heating for a longer time is required unless the voltage between the electrodes is made larger. FIG. 6 shows electrodes when the objects A to be thawed having different heights H (ratio to the distance D between electrodes) are thawed in the same time as the objects A to be thawed having a height of 80% of the distance D between electrodes. Shows the ratio of the voltages applied in between. In FIG. 6, the voltage between the electrodes applied when thawing the object A to be thawed having a height of 80% of the distance D between the electrodes is set to 1 (reference). Further, FIG. 7 shows an electrode when the object A to be thawed having a height H = 2 to 16 cm when the distance D between the electrodes is 20 cm is thawed in the same time as the object A to be thawed having a height H = 16 cm. The ratio of the voltage applied between them is shown. Here, if the ratio of the voltage between the electrodes exceeds about 2.2, there is a possibility that the possibility of discharge increases, the necessity of boosting design of the matching circuit, and the accompanying significant size expansion of the apparatus main body. Therefore, it is desirable that the ratio of the voltage between the electrodes is 2.2 or less.

Based on the above, sashimi fillets, sushi, chunks of meat, and cakes can be easily thawed between electrodes as the defrosted material A, which is more likely to be thawed at home or retail stores such as convenience stores. The distance D was examined. The result is shown in FIG. The evaluation criteria in FIG. 8 are as follows.
◎: Optimal. Good quality and fastest time.
◯: Good quality and stable defrosting are possible. The time is early.
Δ: Thawing is possible, but the thermal efficiency is poor and it takes some time.
▲: It can be decompressed somehow, but the result is unstable. It is very inefficient and takes a lot of time.

With reference to FIG. 6, in order to keep the ratio of the voltage between the electrodes within 2.2, it is desirable that the height H of the object to be thawed A is 15% or more of the distance D between the electrodes. At this time, it is assumed that the object to be thawed is a grip. Here, assuming that the average height of the grip is 4 cm, the inter-electrode distance D satisfying the condition of 15% or more of the inter-electrode distance D is 27 cm or less. As a result, when the grip sushi is thawed using the high-frequency heating device 100, uneven heating of the object to be thawed A (grip sushi) can be suppressed.

In order to reduce the ratio of the voltage between the electrodes, it is more desirable that the height H of the object to be thawed A is 20% or more of the distance D between the electrodes. That is, the distance D between the electrodes is more preferably 20 cm or less.

Further, in order to adapt the fish fillet (height 3.5 cm) having a lower height H by thawing, the distance D between the electrodes is preferably 23 cm or less, and more preferably 17 cm or less (FIG. 8). reference).

Further, in order to adapt the tuna fence for sashimi (height 2 cm) having a lower height H by thawing, the distance D between the electrodes is preferably 13 cm or less, and more preferably 10 cm or less (Fig.). 8).

If the distance between the object to be thawed and each electrode is less than 0.5 cm, the electrodes and the object to be thawed are too close to each other, and discharge is likely to occur. In many cases, the actual object to be thawed is not strictly a rectangular parallelepiped, and tuna fences and the like may be deformed due to rigor mortis during thawing. This deformation also raises the possibility that the object to be thawed may come into contact with the electrodes. Therefore, it is desirable to secure a space of 0.5 cm between the upper and lower electrodes, for a total of 1.0 cm, as a packaging material, an insulator, and a clearance component of the object to be thawed.

Considering the clearance with each electrode as described above, the lower limit of the distance D between the electrodes is 3.0 cm based on the fillet for sashimi (height 2 cm) such as a tuna fence with a low height H. .. When the distance D between the electrodes is 3.0 cm or more, it is possible to secure a clearance with the electrodes suitable for the object to be thawed having a low height H.

Further, in the case of an object to be thawed having a height higher than that of the tuna fence, for example, the lower limit value of the distance D between electrodes can be set as follows. In the case of an object to be thawed having a height of about 4 cm such as a sushi pack, the distance D between the electrodes is set to 5 cm or more. In the case of an object to be thawed having a height of about 6 cm such as lump meat, the distance D between electrodes is 7.5 cm or more. In the case of an object to be thawed having a height of about 8 cm such as cakes, the distance D between the electrodes is set to 10 cm or more.

Many frozen foods, such as sushi and cakes (for example, Mont Blanc, shortcake), have some height differences. In order to prevent uneven heating temperature during thawing caused by the difference in height of the object to be thawed, it is preferable to set the distance D between the electrodes so that it is within 80% of the maximum height of the object to be thawed.

As described above, the upper electrode 1a is connected to the movable portion 8 and can move in the vertical direction according to a command from the control circuit 6. That is, it is possible to change the distance D between the electrodes. Therefore, the distance D between the electrodes can be changed to an optimum value according to the height of the object A to be thawed.

The height of the object to be thawed A can be measured, for example, by installing a height detection sensor in the heating chamber 9. Alternatively, the barcode B of the object to be heated A may include information on the height of the object to be heated A. In this case, the reading unit 4 can acquire information on the height of the object A to be heated by reading the barcode B of the object A to be heated. The control circuit 6 moves the upper electrode 1a in the vertical direction based on the information regarding the height of the object to be heated A obtained via the height detection sensor or the reading unit 4, and for example, the above-mentioned object A to be defrosted. Depending on the type and height H, the distance D between the electrodes can be set to an optimum distance within a range of about 3.0 cm or more and about 27 cm or less. Here, about 3.0 cm means a range of up to about 3.0 cm ± 1.0 cm with 3.0 cm as the median value. Further, about 27 cm means a range of up to about 27 cm ± 1.0 cm with 27 cm as the median.

As a result, it is possible to make it more difficult for uneven heating to occur with respect to many types of objects to be thawed. Further, by setting the distance D between the electrodes to the range of about 3.0 cm or more and about 27 cm or less, the high frequency heating device 100 can be miniaturized.

(About the area of the upper electrode 1a and the lower electrode 1b)
Subsequently, the area of the surface (the surface facing the object to be thawed A) of the plate-shaped upper electrode 1a and the lower electrode 1b will be described. Here, an example in which the upper electrode 1a and the lower electrode 1b are formed of plate-shaped electrodes having the same shape and the same area will be described. However, in another aspect of the present invention, at least one of the upper electrode 1a and the lower electrode 1b may be divided into a plurality of electrodes. In this case, the area of the electrode means the total area of the areas of each surface (the surface facing the object to be thawed) of the plate-shaped electrode divided into a plurality of parts.

Generally, when the area of the electrode is small, it becomes difficult to thaw an object to be thawed having a size greatly exceeding the electrode size. On the other hand, if the area of the electrode is widened, the amount of current increases and the wiring loss increases. Therefore, a cooling mechanism such as a fan provided in the heating chamber needs to have a higher capacity. However, increasing the size of the exhaust heat fan for cooling leads to an increase in the size of the device, and it becomes difficult to reduce the high-frequency heating device to the dimensions used in the kitchen of a store or at home.

The relationship between the dimensions in the heating chamber 9 and the dimensions of the electrodes and the dimensions of the object to be thawed A will be described below with reference to FIGS. 9 and 10. FIG. 9 schematically shows each space formed when the object A to be thawed is placed on the lower electrode 1b in the heating chamber 9.

As shown in FIG. 9, when the object to be thawed A is placed on the lower electrode 1b, a space B in which the object to be defrosted does not exist is formed between the upper electrode 1a and the lower electrode 1b. The upper electrode 1a and the lower electrode 1b to which a high voltage is applied are arranged in a metal housing (that is, in the ground). Then, a region of space C is formed above the upper electrode 1a.

When a high frequency voltage is applied to each electrode, the space A + the object to be thawed A, the space B, and the space C form a capacitor. A high-frequency current that does not contribute to giving energy to the object A to be thawed flows in the space B and the space C. When the height D2 of the space C is reduced, the high frequency current flowing in the space C increases. In addition, the electric field strength between the upper electrode 1a and the housing becomes large, which may cause a discharge. On the other hand, if the height D2 of the space C is increased, the high frequency current is reduced, but the unused space is increased and the entire device is enlarged.

In FIG. 10, when the heights of space B and space C are equal (that is, D1 = D2 = D) and the electrode area is n times the bottom area of the object A to be thawed, each space is used as an electrical equivalent circuit to form a capacitor. It is a figure when it is represented by.

Here, the capacitances Ca, Cb, and Cc of each space are as follows.
Ca = 2.5ε ₀ · S / D
Cb = ε ₀・ (n-1) ・ S / D
Cc = ε ₀・ n ・ S / D

The total current / thawed product current is expressed as follows, where 1 is the voltage applied to each capacitor. Here, the total current is the total current value flowing in the circuit, and the thawed product current is the current value flowing in the space A + the thawed material A.
{(2n-1) /2.5+1}

In the above equation, when the value of n is changed and the total current / thawed product current with respect to the electrode area / thawed material bottom area (n) is graphed, it becomes as shown in FIGS. 11 and 12. FIG. 11 shows n = 1 to 8, and FIG. 12 shows n = 1 to 28.

Considering the demand for thawing of various foodstuffs that are expected to be cooked in the kitchen of homes and restaurants, and the equipment design considering the amount of exhaust heat and the required exhaust heat fan size, the wiring loss ratio is kept within 15. Is desirable.

Here, examples of foodstuffs for which relatively high thawing demand is expected include frozen cakes, sashimi fillets (for example, tuna fences), chunks of meat, sushi packs (small), and sushi packs (large). The wiring loss when processing was calculated. Calculation In each area of the base of each of these ingredients was assumed to be about ^{50cm 2, 100cm 2, 150cm 2} , 200cm 2, 300cm 2. The result is shown in FIG.

By setting the electrode area to 300 cm ² or more and 1200 cm ² or less, it is possible to make a small defroster that can easily and easily thaw frozen foods such as sushi at retail stores and the like. Further, referring to the result shown in FIG. 13, by ^{setting the electrode area to 600 cm 2} or less, a relatively wide variety of foodstuffs (that is, tuna fences, lump meat, etc.) can be used without the need for detailed settings for each foodstuff. It can be seen that the wiring loss ratio can be maintained at a good value for the ingredients and cooked ingredients such as sushi packs. Regarding cake, the wiring loss ratio is relatively high when the electrode area is 600 cm ^2. When thawing a food material having a relatively small area as described above, the wiring loss ratio can be kept low by thawing a plurality of foods (for example, two) at the same time.

Further, FIG. 14 shows the total current when the same foodstuff (that is, frozen cake, sashimi fillet (for example, tuna fence), lump meat, sushi pack (small), sushi pack (large)) is thawed. / The result of calculating the thawed current (current ratio of total current to heated current) is shown. Similar to FIG. 13, the refrigeration cakes, fillets for sashimi (e.g., tuna fence), mass meat, sushi pack (small), and the bottom area of sushi pack (large) is about 50 cm ^2, respectively, 100 cm ^2, 150 cm ^2, It was assumed to be 200 cm ² and 300 cm ^2.

The total current / thawed product current when the thawing process is performed in the high frequency heating device 100 is preferably 5.5 or less. As a result, it is possible to suppress an increase in wiring loss. Further, referring to FIG. 14, the electrode area of the high frequency heating device 100 is set to 300 cm ² or more and 600 cm ² or less so as to suppress an increase in wiring loss and to cope with thawing processing of a wider variety of foodstuffs. Is preferable.

(Summary of the first embodiment)
Although one embodiment of the present invention has been described above, the prior art and its problems which are the premise of the present invention will be described here.

Conventionally, microwave ovens have been widely used as thawing machines for thawing frozen foods in relatively small facilities such as homes, in-store kitchens, and convenience stores. A microwave oven is a microwave oven that raises the temperature by giving energy to the vibrator of water molecules by electromagnetic waves of 2.45 GHz.

In addition to the microwave oven, as a defrosting method by internal heating, there is also a method called microwave heating by transmitting from an amplifier using a semiconductor element. Further, as another thawing method, there is a method of raising the temperature of the object to be heated by heat transfer from the outside such as an atmosphere. Specifically, the frozen food is left in a refrigerator, room temperature, running water, or the like.

In addition, larger facilities such as prepared food and bento manufacturing plants and central kitchens of restaurant chains use industrial defrosters using HF or VHF waves. Such industrial thawing machines thaw large amounts of foodstuffs such as frozen shirasu blocks and chunks of meat.

Reasons for using HF wave or VHF wave include the following three advantages over microwaves.
a) The difference between the loss factors of water and ice is small, and the melted water is heated more strongly, so thermal runaway is less likely to occur.
b) When the frequency is low, the power halving depth is deep, and the energy penetrates deep into the thawed product.
c) As the thawed material melts and the ice becomes water, high-frequency voltage is not applied (that is, it becomes difficult to heat), and it is easy to make a half-thawed state of -5 ° C to -1 ° C without causing thermal runaway.

In recent years, remarkable progress and changes have been seen in the technological, infrastructure, and social conditions surrounding food distribution.

For example, in terms of technology, freshness maintenance technologies such as ikejime of fish at sea and in harbors, advanced freezing technology for maintaining freshness such as CAS (Cell Alive System) and proton freezing, have been greatly developed. In terms of infrastructure such as logistics, low-temperature transportation services such as cool flights and refrigeration equipment are fully equipped, and an environment for maintaining and delivering frozen and refrigerated foodstuffs is in place. Due to such enhancement of infrastructure, the service industry that delivers high value-added products directly to individuals with freshness, such as direct delivery from production areas and backorders, is growing rapidly.

In addition, as a change in the society surrounding food, the following major changes have occurred in the dietary habits and interest in food in the world as a whole.
a) Due to economic development, the improvement of freshness preservation technology mentioned above, and the enhancement of infrastructure, the consumption and price of meat and fish have increased worldwide. Sushi, sashimi, etc., which were once spooky raw food, have established a solid position as sophisticated high-class food.
b) In addition to the improvement of technology and the enhancement of infrastructure, the rationalization and efficiency of distribution have progressed, and the required standards for freshness of foodstuffs have increased. "Direct delivery from the production area" and "morning picking", which were once valid phrases, are no longer commonplace, and fresh fish picked in the morning are offered to consumers at restaurants such as rotating sushi in the daytime.

c) While selling freshness, food loss has become a management and ethical issue, and various measures have been developed to extend the expiration date. For example, preservation processing technology such as smoke, food preservation technology using food additives such as preservatives and antioxidants, container packaging technology represented by canning and vacuum packing, and the like can be mentioned.
d) The quality of frozen foods has improved, making it convenient and delicious. With a cooking device such as a microwave oven, you can easily taste the freshly made food, forming a large market.
e) Due to changes in values and concerns about safety, support for natural foods such as additive-free foods and organic foods has increased. The ready-to-eat and restaurant industries are required to devise ways to maintain freshness and taste at the same time by enabling long-term storage with advanced refrigeration technology and packaging technology instead of food additives.

As mentioned above, various situations surrounding food distribution have undergone major changes. Along with this, various improvements have been made to the processing technology of frozen foods. On the other hand, the current thawing technology has problems such as overheating and deterioration of texture. In particular, there are many inadequate points in the thawing technique to a normal temperature or an appropriate temperature in a short time performed in a relatively small facility such as a kitchen in a home or a store. For example, foods that are eaten in the normal temperature range of several degrees Celsius to 20 degrees Celsius, such as sushi, namagashi, cakes with fresh cream, etc. It is difficult to thaw easily. For example, there are the following problems.

Microwaves in microwave ovens are less likely to be absorbed by ice than water due to differences in loss factors. Therefore, the following can be mentioned as disadvantages at the time of decompression.
1) It takes time. This is to reduce the output and heat in the so-called "thawing mode" in order to prevent magnetron damage due to microwave reflection.
2) Uneven thawing is likely to occur. For example, in the case of lump meat, about 2 cm from the surface layer is strongly heated, but electromagnetic waves do not penetrate inside the lump, so that a large temperature difference occurs inside and outside the thawed product.
3) Local heating is likely to occur. As described above, as soon as the surface of the thawed material is strongly heated and becomes water, it suddenly begins to absorb microwaves, causing a phenomenon called thermal runaway.

Further, in the thawing by leaving at room temperature, the temperature becomes uniform according to the atmosphere if left unattended. However, it also has the following disadvantages.
1) Depending on the amount and shape of the ingredients, it may take several hours or more to thaw. In store kitchens, it is often thawed from the night before use.
2) Thawing for a long time causes denaturation of food such as deterioration of taste due to oxidation and umami outflow due to drip (the cell membrane of food is damaged due to the long passage time of the maximum ice crystal formation zone).
3) Long-term thawing has a risk of breeding bacteria and molds that cause food poisoning on the surface of the thawed product, which increases a hygienic risk especially for raw food.

Further, although thawing with running water can be thawed in a relatively short time, it has the following two disadvantages.
1) Since the required time varies depending on the conditions such as room temperature, manpower is required for time management and frequent status confirmation.
2) Conditions suitable for thawing under running water (that is, occupied space such as a large-capacity sink, packaging form such as a vacuum pack, water supply facility construction, etc.) are required. In addition to this, thick ingredients such as chunks of meat require some time to thaw.

As described above, the defroster using the HF wave or the VHF wave has an advantage in defrosting as compared with the microwave oven using the microwave. Therefore, it is widely used as an industrial defroster in a large facility. However, since the HF wave or VHF wave has a deep electric power half depth, it is suitable for thawing foodstuffs having a relatively large size of several kg, and is not suitable for thawing final processed foods purchased by general consumers. In addition, the current HF wave or VHF wave thawing machine mainly targets foodstuffs composed of a single material as thawing objects, and if the object to be heated is composed of various substances, dielectric loss will occur. Higher ingredients are heated more strongly. Therefore, when processed foods such as bento boxes in which different ingredients are piled up little by little are thawed, uneven heating occurs.

As described above, the conventional defroster using HF wave or VHF wave is not suitable for defrosting in a small facility such as a store kitchen where a small amount of required amount is defrosted, and is not miniaturized. Therefore, in in-store kitchens such as homes and convenience stores, defrosters using HF waves or VHF waves are not as widespread as microwave ovens.

For example, in a high-frequency heating device that uses a dielectric heating method using a high-frequency electric field of HF waves or VHF waves, the optimum output, reactance component of the matching circuit, and drive time differ depending on the object to be thawed (heated). It is required to control each of them comprehensively. However, the food cooking apparatus (microwave oven) disclosed in Patent Document 1 controls only the driving time. When this method is applied to a high-frequency heating device such as the present embodiment, high-quality thawing cannot be performed, and overheating, insufficient heating, and uneven heating may occur.

Further, in Patent Document (Japanese Unexamined Patent Publication No. 2004-349116), a method of uniformly heating and thawing an object to be heated having an indefinite shape having various heights and shapes in a dielectric heating device using HF waves or VHF waves. Has been proposed. In this method, the object to be heated is covered with an inclusion having a relative permittivity equal to or higher than the relative permittivity of the object to be heated to fill the voids, thereby preventing local intensive heating. However, when it is used frequently and repeatedly, such as in a store kitchen or convenience store, it is difficult to put in and take out the object to be heated, and it may get caught during work and damage the object to be heated or inclusions. It causes problems in sex, life, and maintenance.

As mentioned above, there has been a strong social demand in recent years to easily eat final processed foods such as sushi and namagashi while suppressing the use of additives, and the cryopreservation technology for that purpose has greatly evolved. There is. On the other hand, the thawing technology lags behind the progress of freezing and refrigerating technology, and the current situation is that satisfactory technology is not widely used. In particular, in small-scale facilities such as home kitchens and store kitchens just before the mouth of consumers, versatility that allows only the required number of people to be thawed at an appropriate temperature in a relatively short time with high quality. There is still no expensive defroster.

Therefore, in one aspect of the present invention, in view of the above problems, a defroster (high frequency heating device) that is easy to use like a microwave oven is provided.

The high-frequency heating device 100 according to one aspect of the present invention includes a voltage application unit 20 (high-frequency power supply 2 and matching circuit) that applies a high-frequency voltage between the upper electrode 1a, the lower electrode 1b, and the upper electrode 1a and the lower electrode 1b. 3) and a movable portion 8 connected to the upper electrode 1a are provided. Since the movable portion 8 is provided, the distance between the upper electrode 1a and the lower electrode 1b can be changed.

In the high frequency heating device 100 according to the present embodiment, the distance D between the two electrodes (upper electrode 1a and lower electrode 1b) is within the range of 3.0 cm or more and 27 cm or less. Further, the areas of the flat plate-shaped upper electrode 1a and the lower electrode 1b are each 600 cm ² or less. As a result, the device can be sized to be suitable for use in a small facility such as a home or a store, and a highly versatile high-frequency heating device can be obtained.

For example, the high-frequency heating device 100 according to the present embodiment can be used in a small space where a large machine cannot enter, such as a convenience store, a store kitchen, and a kitchen at home. Further, since the high-frequency heating device 100 can be as large and heavy as a microwave oven, even one person can transport, move, install, and the like. Further, unlike the device described in Patent Document (Japanese Unexamined Patent Publication No. 2004-349116), detailed setting of physical conditions is not required, so that the device can be used easily and conveniently without deteriorating durability and convenience. can do.

Further, according to the configuration of the high-frequency heating device 100, the current ratio between the total current and the current of the object to be heated at the time of heating the object to be heated can be set to 5.5 or less, and the wiring loss can be suppressed.

Further, the upper electrode 1a can be moved by the movable portion 8 to set the distance D between the electrodes to an optimum value within the above range according to the height of the object to be heated. As a result, it is possible to suppress the occurrence of overheating, insufficient heating, uneven heating, etc., and realize high-quality thawing.

Further, the high-frequency heating device 100 stores the reading unit 4 that reads the type, size, etc. of the object A to be heated and the control information when the object A to be heated and the object A to be heated are associated with each other. It includes a memory 5 and a control circuit 6 that changes the heating time, output power, and the like based on the control information corresponding to the object A to be heated determined by the reading unit 4.

According to this configuration, suitable heating settings can be made for more food types and foodstuffs. For example, at convenience stores where there are dozens of types of bento boxes alone, each product can be accurately identified and a suitable heating program can be selected. Further, if the weight, shape, size, etc. of the object to be heated are predetermined standard products, the optimum thawing conditions can be set by reading the barcode without manually inputting.

Further, by discriminating the type of the object to be heated, it is possible to heat (thaw) to the optimum finish temperature suitable for the characteristics of the object to be heated. For example, when the object to be heated is raw meat for heating, the finished temperature can be set to around 0 ° C. from half-thawing. When the object to be heated is frozen sushi, the finished temperature can be about 20 ° C. When the object to be heated is a cake containing fresh cream, the finished temperature can be about 5 ° C. Further, since the radiant heat sensor 21 is provided in the heating chamber 9, it is possible to set up a heating program according to the state of the object to be heated before heating. For example, if the temperature of the object to be heated before heating is high, the heating time may be shortened.

When the high-frequency heating device 100 is provided with a weight sensor, the heating time (thawing time), output power (output wattage), and the like can be changed in consideration of the weight information transmitted from the weight sensor. it can.

In this way, the high-frequency heating device 100 specifies the type of the object to be heated by using the reading unit 4 and the operation unit 7, and the state of the object to be heated by using various sensors such as the radiant heat sensor 21 and the weight sensor. Can be grasped. Therefore, the control circuit 6 enables fine control of the thawing process according to the type and state of the object to be heated. Then, the finished condition of the object to be heated can be optimized. Further, by providing various sensors such as a radiant heat sensor 21 and a weight sensor, a part or all of the control can be automated.

Further, according to the high-frequency heating device 100 according to one aspect of the present invention, in a small-scale restaurant where demand cannot be predicted, frozen foods can be thawed in a short time each time according to an order. Therefore, food loss and opportunity loss can be reduced. In addition, since high-quality thawing can be performed in a short time, it is possible to suppress the growth of food poisoning-causing bacteria during thawing as compared with neglected thawing. Therefore, it can contribute to food safety.

[Second Embodiment]
Subsequently, a second embodiment of the present invention will be described. FIG. 15 shows the internal configuration of the high frequency heating device 200 according to the second embodiment.

The high frequency heating device 200 includes a heating chamber (thawing chamber) 9. Further, as shown in FIG. 15, the high-frequency heating device 200 has a voltage application unit 20, a control circuit (control unit) 6, a reading unit 4, an operation unit (input unit) 7, and a memory 5 outside the heating chamber 9. And so on. As can be seen by comparing FIG. 15 and FIG. 1, the high-frequency heating device 200 is different from the high-frequency heating device 100 according to the first embodiment in that the movable portion 8 is not provided. Further, the configuration in the matching circuit 203 is different from that of the first embodiment. For other configurations, the same configuration as that of the high frequency heating device 100 can be applied. Therefore, detailed description of each component will be omitted.

FIG. 16 is a circuit diagram showing a circuit configuration between the electrodes 1a and 1b and the high frequency power supply 2. The voltage application unit 20 applies a voltage to each electrode in the heating chamber 9.

The voltage application unit 20 applies a high frequency voltage between the upper electrode 1a and the lower electrode 1b. The voltage application unit 20 has a high frequency power supply 2, a matching circuit 203, and the like as main constituent members. The same configuration as in the first embodiment can be applied to the high frequency power supply 2.

The matching circuit 203 includes variable capacitors (variable reactance elements) 3a and 3b, a variable coil (variable reactance element) 203c, and the like. The same configuration as in the first embodiment can be applied to the variable capacitors 3a and 3b.

The variable coil 203c has a plurality of coils connected in a switchable manner. As a result, the variable coil 203c can be switched to a plurality of inductance values.

With this configuration, the matching circuit 203 cancels out the reactance of the capacitor composed of the upper electrode 1a and the lower electrode 1b. Further, the matching circuit 203 can match the input impedance to the matching circuit 203 with the output impedance to the amplifier by adjusting the values of the variable capacitors 3a and 3b and the variable coil 203c. As a result, a high-frequency electric field can be efficiently applied to the object to be heated (object to be thawed) A.

Similar to the first embodiment, the coil 12 is arranged between the variable capacitor 3b of the matching circuit 203 and the upper electrode 1a.

(Regarding the control of the capacitance of the variable capacitors 3a and 3b)
The memory 5 of the high-frequency heating device 200 according to the present embodiment stores the capacitances of the variable reactance elements (variable capacitors 3a and 3b) in the matching circuit 203 as control information when heating the object to be heated A. Then, the control circuit 6 controls the capacitances of the variable capacitors 3a and 3b in the matching circuit 203 based on the control information regarding the capacitances of the variable reactance elements (variable capacitors 3a and 3b) stored in the memory 5.

The high-frequency heating device 200 can efficiently apply a high-frequency electric field to the object to be heated by adjusting the variable reactance elements (variable capacitors 3a and 3b and the variable coil 203c) of the matching circuit 203, and has a high frequency with little temperature unevenness. High quality food can be thawed with high efficiency.

(About the distance between the upper electrode 1a and the lower electrode 1b)
Subsequently, the distance between the electrodes of the upper electrode 1a and the lower electrode 1b will be described. The high-frequency heating device 200 according to the present embodiment is suitable for thawing food in a retail store such as a home or a convenience store. In the high-frequency heating device 200, the distance D between the upper electrode 1a and the lower electrode 1b is set in consideration of the size, quantity, shape, etc. of the object A to be heated, which is assumed when used in a home or a retail store. It is set to be within the range of 3.0 cm or more and 27 cm or less. As a result, the high-frequency heating device 200 can be downsized.

The high-frequency heating device 200 according to the present embodiment is not provided with the movable portion 8. Therefore, the distance D between the upper electrode 1a and the lower electrode 1b is set to any distance within the range of 3.0 cm or more and 27 cm or less. At this time, in consideration of the use of the high-frequency heating device 200, it is preferable to set the distance D between the electrodes based on the height H of the more frequently used foodstuff.

For example, the ratio of the height H of the object to be thawed (object to be heated) A to the distance D between the electrodes is 0.8 or less (that is, the height H of the object to be heated A is within 80% of the distance D between the electrodes). As described above, it is preferable to set the distance D between the electrodes. As a result, the energy ratio in each part of the object A to be thawed can be set to 0.4 or less (see FIG. 4). That is, the heating unevenness of the object A to be thawed can be suppressed to be relatively small.

The high-frequency heating device 200 according to the present embodiment can also be used as a dielectric heating device of a thawing processing system for thawing a frozen sushi set by dielectric heating treatment using a high-frequency electric field of HF wave or VHF wave. In this case, the high-frequency heating device 200 includes a communication interface 230 as a receiving unit that receives an instruction to thaw the frozen sushi set (see FIG. 15).

This thawing processing system includes a high frequency heating device 200 and a server 240 as main components. The high frequency heating device 200 can be connected to the server 240 via the Internet, a router, or the like.

The communication interface 230 in the high frequency heating device 200 is realized by an antenna or a connector. It receives various signals, various data, various commands, etc. transmitted from the server 240. In this decompression processing system, for example, when a user having an information terminal capable of communicating with the server 240 orders a sushi pack by performing a predetermined operation, the order information is transmitted to the server 240. Then, the server 240 selects the corresponding frozen sushi pack from various frozen sushi packs stored in the freezer of the sushi manufacturer or the like. The selected frozen sushi pack is thawed using a high-frequency heating device 200 and provided to the user.

In the above description, an example in which the receiving unit is provided inside the high frequency heating device 200 is given, but in another aspect of the present invention, the receiving unit is a receiving device different from the high frequency heating device 200. It can also be realized. Further, a similar thawing processing system can be configured by using the high frequency heating device 100 instead of the high frequency heating device 200.

Using the above thawing processing system, when a purchaser orders a sushi pack at a store or on the Internet, a person on the selling side (for example, a clerk) puts a frozen sushi set into a dielectric heating device (for example, a high frequency heating device 200). ), And the thawed frozen sushi set can be provided to the purchaser. Such a sushi set providing and selling system is also an example of the present invention.

Frozen sushi is difficult to thaw well in a microwave oven, so if you sell sushi at a retail store, you need to store it in a refrigerator, which has a relatively short expiration date, and you have to discard the unsold sushi. Did not get.

Therefore, by providing a dielectric heating device suitable for thawing food in a retail store, it is possible to freeze and store the food, and it is possible to thaw the food at a high quality when and as much as necessary. Therefore, sushi whose expiration date has expired is not wasted, and sushi can be easily sold at convenience stores, for example.

[Third Embodiment]
Subsequently, a third embodiment of the present invention will be described. In the third embodiment, the frozen food suitable for thawing using the above-mentioned high-frequency heating device 100 or 200 will be described. The frozen food (specifically, frozen sushi 300) described in this embodiment is a frozen food according to one aspect of the present invention.

FIG. 17 shows the appearance of the frozen sushi 300 according to the present embodiment. Frozen sushi 300 is thawed by dielectric heating treatment with a high frequency electric field of HF wave or VHF wave, and becomes edible. The dielectric heating treatment of HF wave or VHF wave by a high frequency electric field can be performed by using the above high frequency heating device 100 or 200.

The frozen sushi 300 is composed of a material portion (upper layer portion) 301 located above and a rice sushi portion (lower layer portion) 302 located below. When the material portion 301 is thawed using a high-frequency heating device 100 or the like, the material portion 301 is located on the upper side, and the rice portion 302 is located on the lower side. The rice sushi portion 302 is placed on the bottom plate 11 and thawed.

In the frozen sushi 300, the water content of the upper layer portion 301 is larger than the water content of the lower layer sushi portion 302. The amount of water here means the amount of water (weight) per unit volume.

In thawing of VHF waves or HF waves in an electric field by a dielectric heating device used in a thawing process, those having a small amount of water are more likely to be heated than those having a large amount of water. This will be described with reference to FIGS. 18 and 19.

FIG. 18 is a diagram showing a temperature rise due to a defrosting treatment of a VHF wave or an HF wave in an electric field in the case of an object to be heated in which the water content of the upper layer portion is larger than the water content of the lower layer portion. As shown in FIG. 18, the upper layer portion having a large amount of water has a characteristic that the temperature rise is slower than that of the lower layer portion.

FIG. 19 is a diagram showing a temperature rise due to a defrosting process of a VHF wave or an HF wave in an electric field in the case of an object to be heated in which the water content of the upper layer portion is smaller than that of the lower layer portion. As shown in FIG. 19, the upper layer portion having a small amount of water has a characteristic that the temperature rises faster than the lower layer portion.

In this way, in the thawing process by dielectric heating of VHF waves or HF waves in an electric field, the smaller the amount of water, the easier it is to heat. It is possible to generate a temperature difference.

In general, it is said that sushi is more delicious when it is warmer than sushi rice, and by intentionally creating a temperature difference between the upper and lower layers, it is possible to provide sushi that feels more delicious.

FIG. 20 shows the water content of the main sushi ingredients in% by weight. As shown in FIG. 20, the rice sushi rice has a water content of about 60%. In order to create an ideal temperature difference between the upper and lower layers, it is possible to provide a sushi pack that can be felt more delicious by selecting a material that has a higher water content than rice sushi rice.

In the example shown in FIG. 20, the water content of tuna (toro), salmon (toro), salmon roe, and shimesaba is less than 60%, which is the water content of sushi rice. It is not possible to create an ideal temperature difference between the upper and lower layers. When producing a frozen sushi pack 300a consisting of a plurality of sushi platters using such ingredients, these are adjusted by adjusting the moisture content of the sushi rice to be used so that the moisture content is lower than that of the ingredients. It can also be used for sushi with a small amount of water. Alternatively, when selecting the material for the frozen sushi pack 300a, it is possible not to select the material having a water content of 60% or less.

In the present embodiment, frozen sushi 300 has been described as an example of frozen food, but it can also be applied to other frozen foods composed of an upper layer portion and a lower layer portion. FIG. 21 shows frozen chirashizushi 300b, frozen seafood bowl 300c, frozen mousse cake 300d, and frozen cheesecake 300e as other examples of frozen foods. Each of these foods is composed of an upper layer 301 (material, mousse, cheese, etc.) and a lower layer 302 (vinegared rice, rice, sponge, etc.) having a lower water content than the upper layer.

As described above, the frozen food according to the present embodiment is composed of an upper layer portion 301 and a lower layer portion 302 having a smaller water content than the upper layer portion. As a result, when the dielectric heating treatment is performed by the high-frequency heating device 100 or the like, the temperature rise of the lower layer portion 302 can be relatively accelerated, and the overheating of the upper layer portion 301 can be prevented, and between the upper layer and the lower layer. A temperature difference can be intentionally created.

Further, in a frozen food having a two-layer structure of an upper layer portion and a lower layer portion, the water content per unit volume of the lower layer portion is 65% or more and 95% or less of the water content per unit volume of the upper layer portion. Is preferable. The water content here is calculated as a ratio by weight.

By adjusting the water content of the upper layer portion and the lower layer portion as described above, the temperature difference between the upper layer portion and the lower layer portion can be made an optimum value.

[Fourth Embodiment]
Subsequently, a fourth embodiment of the present invention will be described. In the fourth embodiment, the method for producing a food product according to one aspect of the present invention will be described. FIG. 22 shows each step of the food manufacturing method according to the present embodiment.

As shown in FIG. 22, the method for producing food according to the present embodiment is mainly carried out in three steps of a cooking step, a freezing step, and a thawing step. Hereinafter, each step will be described.

The cooking process is the process of cooking food. In this cooking process, each ingredient used for processed foods such as lunch boxes and sushi packs is cooked in the same process as the conventional cooking process to produce processed foods. The description of the conventional cooking process will be omitted here.

In the freezing process, the processed food cooked in the cooking process is frozen. In the freezing step, the processed food is rapidly frozen so that the temperature of the processed food reaches −20 ° C. within 120 minutes from the start of the freezing process. As a method of quick freezing, conventionally known methods such as an air blast method (air freezing), a liquid method (liquid freezing), a contact method (contact freezing), and a liquefied gas method can be applied.

As shown in FIG. 23, in the process of temperature decrease during freezing, there is a temperature zone called the maximum ice crystal formation temperature zone in which the temperature does not easily decrease, and if it takes a long time to pass through this temperature zone during freezing treatment, It is known that the quality of food deteriorates.

Therefore, by freezing the food so that it reaches −20 ° C. within 120 minutes from the start of the freezing treatment, deterioration of the quality of the food can be prevented. In particular, in the case of foods using white rice or wheat flour, if the food is frozen for a long time, the starch aging phenomenon occurs, and the taste and texture are significantly deteriorated. Therefore, when freezing foods containing a large amount of starch such as white rice and wheat flour, it is more preferable to quickly freeze the food from room temperature of about 20 ° C. to −20 ° C., for example.

In the thawing step, the frozen processed food is thawed by dielectric heating treatment with a high frequency electric field of HF wave or VHF wave. This thawing step can be carried out, for example, by using the high frequency heating device 100 or 200 described in the first or second embodiment described above. Specifically, the processed food (object to be thawed) is sandwiched between the upper electrode 1a and the lower electrode 1b, and the processed food is dielectrically heated by applying a high frequency electric field of HF wave or VHF wave between the electrodes. Then, in the thawing step, the temperature of the processed food after thawing is controlled within the range of + 5 ° C. or higher and + 60 ° C. or lower.

Similar to the freezing process, in the process of temperature rise during the thawing process, there is a temperature zone called the maximum ice crystal formation temperature zone where the temperature does not rise easily, and if it takes a long time to pass through this temperature zone during thawing. , It is known that the quality of food deteriorates.

Therefore, by rapidly thawing the processed food frozen by the above-mentioned high-frequency heating device, it is possible to prevent the quality of the food from deteriorating. In particular, in the case of foods using white rice or wheat flour, if the food is thawed over a long period of time, the starch aging phenomenon occurs, and the taste and texture are significantly deteriorated. Therefore, when freezing foods containing a large amount of starch such as white rice and wheat flour, rapid thawing is preferable.

As a rapid thawing method, microwave oven heating is generally used, but this method may cause overheating and uneven heating, and frozen food cannot be thawed with high quality. On the other hand, in the defrosting of VHF waves or HF waves in an electric field by the above-mentioned high-frequency heating device, overheating and uneven heating can be suppressed, and higher quality defrosting can be performed.

As described above, after the food is rapidly frozen, it is thawed by dielectric heating with a VHF wave or HF wave electric field, and the finished temperature is set between + 5 ° C. and + 60 ° C., thereby suppressing deterioration due to overheating and specially. It is possible to obtain a food having a good taste and texture without using a simple container or sheet.

The foods produced by the production method according to the present embodiment include, for example, the frozen foods described in the third embodiment described above (for example, frozen sushi 300, frozen sushi pack 300a, frozen chirashizushi 300b, frozen seafood). Examples thereof include foods obtained by thawing a bowl 300c, a frozen sushi cake 300d, and a frozen cheese cake 300e) in the above thawing step.

That is, the food produced by the production method according to the present embodiment is composed of an upper layer portion 301 and a lower layer portion 302 having different water content per unit volume, and the water content per unit volume of the upper layer portion 301. However, it is preferable that the amount of water in the lower layer portion 302 is larger than the amount of water per unit volume. By producing such a food by the above-mentioned production method, it is possible to obtain a food having a good taste and texture by suppressing overheating and uneven heating of the food in the thawing step.

Further, in the food produced by the production method according to the present embodiment, the water content per unit volume of the lower layer portion 302 is 65% or more and 95% or less of the water content per unit volume of the upper layer portion 301. Is preferable. As a result, overheating and uneven heating of food in the thawing step can be more reliably suppressed.

Here, an example of the dielectric heating device used in the above thawing step will be described. As described above, the thawing step can be carried out by using a high frequency heating device 100 or 200, which is an example of the dielectric heating device according to the present invention.

The high-frequency heating devices 100 and 200 include at least two electrodes (that is, an upper electrode 1a and a lower electrode 1b) arranged to face each other, and a high-frequency power source 2 that supplies a high-frequency electric field by an HF wave or a VHF wave to these electrodes. , And a matching circuit 3 and the like.

With this configuration, a high-frequency electric field can be efficiently applied to frozen processed foods, and high-quality foods with little temperature unevenness can be thawed with high efficiency.

Further, the dielectric heating device used in the thawing step may further include a position changing mechanism for changing the position of the electrode. The position changing mechanism is, for example, a movable portion 8 provided in the high frequency heating device 100.

By providing the movable portion 8, the position of the upper electrode 1a can be changed according to the size of the processed food (object to be heated) during dielectric heating. By appropriately setting the distance between the processed food and the upper electrode 1a, energy can be efficiently applied to the frozen processed food, and the thawing time can be shortened.

[Fifth Embodiment]
Subsequently, a fifth embodiment of the present invention will be described. In the fifth embodiment, the frozen sushi set according to one aspect of the present invention will be described. Here, as an example of a frozen sushi set, a frozen sushi pack (assorted sushi) composed of a plurality of sushi will be described as an example. This frozen sushi pack is suitable for thawing by dielectric heating with a high frequency electric field of HF or VHF waves. Good texture and quality can be maintained by thawing the frozen sushi pack according to the present embodiment by dielectric heating treatment using a high frequency electric field of HF wave or VHF wave.

FIG. 24 shows an example of the frozen sushi pack 400 of the present embodiment. The frozen sushi pack 400 is mainly composed of a container 430 and a plurality of sushi 410s and 420s. The container 430 has a tray 431 and an upper lid 432. The individual sushi 410 and 420 have a sushi portion 412 or 422 and a material portion 411 or 421 arranged on the sushi portion.

The rice sushi portion 412 or 422 is composed of vinegared rice. However, in another example, the rice portion may be cooked rice such as white rice or millet rice. The material portion 411 or 421 is composed of, for example, seafood. However, the material portion is not limited to seafood, and may be ingredients such as vegetables, mushrooms, algae, and meat. In addition, processed ingredients such as seafood tempura, grilled egg, mackerel, ribs, and hamburger may be used.

The plurality of sushi 410s and 420s are arranged side by side on the tray 431 of the container 430. In the plurality of sushi 410 and 420, the water content (weight) per unit volume is, for example, 60% (weight%) as a boundary, and the material portion has a water content less than this reference value. It is classified into a group and a second group in which the material portion has a water content equal to or higher than this reference value.

In the present embodiment, the sushi classified into the first group (that is, the sushi having a material having a relatively low water content) is referred to as the first sushi 410. Examples of such first sushi 410 material (first material) include tuna (toro), salmon roe (toro), salmon (toro), and the like (see FIG. 20). Further, the material of the sushi 410 of the first group may be a processed ingredient such as shimesaba.

Further, the sushi classified into the second group (that is, the sushi having a material having a relatively large water content) is referred to as the second sushi 420. Examples of such a second sushi 420 material (second material) include tuna (red meat), salmon, shrimp (boiled), sea bream, and scallop (raw) (see FIG. 20). In addition, the material of the second group of sushi 420 may be processed ingredients such as omelet and squid tempura. The water content of squid tempura is about 69%.

The classification of sushi into the first group and the second group is not limited to the type of material, but is determined by the amount of water contained in the material. That is, even if the material is of the same type, if the water content differs depending on the part or the like, it is classified into a different group.

Further, in the present embodiment, 60%, which is the normal water content of the rice sushi portion, is adopted as the reference value of the water content, but the reference value is not limited to this. The reference value of the water content can be any value within the range of 55% (weight%) or more and 65% (weight%) or less.

In the example shown in FIG. 24, one frozen sushi pack 400 contains three (three pieces) first sushi 410 and two (two pieces) second sushi 420. As described above, in the frozen sushi pack 400, it is preferable that the number of the first sushi 410 classified into the first group is larger than the number of the second sushi 420 classified into the second group. .. Thereby, the total weight (for example, the number of grams) of the first sushi 410 classified in the first group can be made larger than the total weight of the second sushi 420 classified in the second group. ..

When this frozen sushi pack 400 is heated (thawed) by dielectric heating treatment with a high frequency electric field of HF wave or VHF wave, the first sushi 410 having a small water content is easier to warm, and is compared with the second sushi 420. Decompresses faster. Therefore, by making the total weight of the first group composed of the first sushi 410 having a small water content larger than the total weight of the second group composed of the second sushi 420 having a large water content. , The difference in how each sushi with different water content is warmed can be reduced. Therefore, it is possible to suppress the occurrence of uneven heating during the thawing process. Further, by increasing the number of the first sushi 410 having a small water content, the temperature inside the frozen sushi pack 400 tends to rise, and as a result, the frozen sushi pack 400 can be thawed in a shorter time.

When thawing the frozen sushi pack 400, it is preferable to adopt a thawing method according to the thawing step of the food manufacturing method described in the fourth embodiment described above. In this thawing method, it is preferable to use the high frequency heating device 100 or 200 described in the first and second embodiments described above.

Further, when producing the frozen sushi pack 400, it is preferable to adopt a method according to the cooking step and the freezing step of the food manufacturing method described in the fourth embodiment described above. In particular, in the freezing step, it is preferable to quickly freeze the sushi pack so that the temperature of the sushi pack reaches −20 ° C. within 120 minutes from the start of the freezing process.

This makes it possible to store the frozen sushi pack 400 for a long period of time without additives. In addition, for retailers selling sushi packs, it is possible to secure a large amount of inventory and reduce opportunity loss and food loss. Moreover, since each sushi pack can be thawed, the cooking method can be simplified. In addition, even if ectoparasites adhere to the sushi pack during the cooking process, by freezing these ectoparasites together, the growth of ectoparasites is suppressed and the outbreak of ectoparasite-derived diseases is suppressed. be able to.

Subsequently, another example of the sushi pack according to the present embodiment will be described. FIG. 25 shows an example of the frozen sushi pack 400a of the present embodiment. The frozen sushi pack 400a is mainly composed of a container 430 and a plurality of sushi 410s and 420s. The container 430 has a tray 431 and an upper lid 432. The individual sushi 410 and 420 have a sushi portion 412 or 422 and a material portion 411 or 421 arranged on the sushi portion.

Similar to the frozen sushi pack 400, the plurality of sushi contained in the frozen sushi pack 400a consists of a first group composed of a first sushi 410 having a small water content and a second sushi 420 having a large water content. It is classified into a second group to be composed. The total weight of the first group composed of the first sushi 410 is larger than the total weight of the second group composed of the second sushi 420.

In order to realize this, in the frozen sushi pack 400a, the amount of the material portion 411 per piece of the first sushi 410 belonging to the first group is one of the second sushi 420 belonging to the second group. It is larger than the amount of the hit material portion 421. The amount of the material portion here means, for example, the mass (number of grams) of the material. However, in another example, the amount of the material portion may be determined by ^{the volume of the material (cm 3).} Alternatively, the height of the material portion 411 per piece of the first sushi 410 belonging to the first group is higher than the height of the material portion 421 per piece of the second sushi 420 belonging to the second group. It may be increased.

As described above, when the dielectric heating treatment is performed, the first sushi 410 having a small water content is more likely to be warmed than the second sushi 420 having a large water content. Therefore, by making a difference in the amount of material between the first sushi 410 and the second sushi 420, the thawing time required for each sushi is made uniform, the operation is simplified, and the quality is improved by preventing uneven baking. You can aim for improvement. As a result, it is possible to further reduce uneven heating during thawing when one sushi pack is composed of a plurality of types of sushi having different thawing times due to different water ratios.

FIG. 25 shows an example in which two (2 pieces) first sushi 410 and two (2 pieces) second sushi are contained in one frozen sushi pack 400a. .. However, the number of each sushi 410 and 420 is not limited to this. The number of the first sushi 410 and the number of the second sushi 420 may be the same or different. However, the total weight of the first sushi 410 belonging to the first group is larger than the total weight of the second sushi 420 belonging to the second group.

Subsequently, how to arrange the sushi 410 and 420 in the frozen sushi packs 400 and 400a will be described with reference to the drawings.

FIG. 26 shows a rectangular frozen sushi pack 400a in which the first sushi 410 and the second sushi 420 having different water content in the material portion are arranged on the tray 431, two each in a total of four pieces. .. In the example shown in FIG. 26, the first sushi 410 having a small water content and the second sushi 420 having a large water content are alternately arranged.

In this way, by arranging sushi with different water content next to each other, the first sushi 410 heat, which has a material portion with a small water content warmed by thawing, is adjacent to the material portion with a large water content that does not easily rise in temperature. The second sushi 420 having the above can be heated to make the finished temperature uniform.

FIG. 27 shows a frozen sushi pack 400a in which a total of 8 pieces of 1st sushi 410 and 2nd sushi 420, 4 pieces each, are arranged in 3 rows on a substantially square tray 431.

FIG. 28 shows a rectangular frozen sushi pack 400a in which a total of 8 pieces of 1st sushi 410 and 2nd sushi 420, 4 pieces each, are arranged in two rows on a tray 431. In the example shown in FIG. 28, the first sushi 410 having a small water content and the second sushi 420 having a large water content are alternately arranged. The first row is arranged alternately in the order of the second sushi 420 and the first sushi 410 from the left side of the tray 431, and the second row is the first sushi 410 and the second sushi from the left side of the tray 431. They are arranged alternately in the order of 420. In the example shown in FIG. 28, each sushi is in contact with sushi having different water content on at least two sides.

That is, the sushi constituting the frozen sushi pack 400a includes a first material having a small amount of water per unit volume and a second material having a large amount of water per unit volume. Then, for example, as shown in FIG. 28, when the front-back and left-right directions of the frozen sushi pack 400a in the horizontal plane direction are defined, the first sushi 410 having the first material has the second material. The sushi 420 is arranged adjacent to the first sushi 410, and the second sushi is arranged at at least two of the four adjacent positions of front, rear, left, and right with respect to the first sushi 410.

In this way, by arranging sushi with different water content next to each other, the first sushi 410 heat, which has a material portion with a small water content warmed by thawing, is adjacent to the material portion with a large water content that does not easily rise in temperature. The second sushi 420 having the above can be heated to make the finished temperature uniform. In addition, by devising the composition and arrangement of sushi by paying attention to the water content of each material, the composition of the sushi pack can be determined without depending on the type of material, and the appetite of consumers can be satisfied. It becomes.

FIG. 29 shows a frozen sushi pack 400a in which a total of 8 pieces of 1st sushi 410 and 2nd sushi 420, 4 pieces each, are arranged in two rows on a rectangular tray 431. In the example shown in FIG. 29, the second sushi 420 having the material portion having a large water content is arranged on the end side of the tray 431, and the first sushi 410 having the material portion having a small water content is placed in the central portion of the tray 431. It is placed in.

In this way, by arranging the first sushi 410 having a small water content and being easier to warm in the center of the tray 431, the heat of the first sushi 410 can be transferred to the adjacent second sushi 420. .. As a result, the output of the thawing machine can be efficiently converted into thawing heat.

FIG. 30 shows a frozen sushi pack 400a containing a total of 16 pieces of sushi, 4 pieces of the first sushi 410 and 12 pieces of the second sushi 420. In the example shown in FIG. 30, the second sushi 420 having the material portion having a large water content is arranged at the four ends of the rectangular tray 431, and the first sushi 410 having the material portion having a small water content is placed in the tray. It is located in the center of 431.

FIG. 31 shows a frozen sushi pack 400a containing a total of 12 pieces of sushi, 4 pieces of the first sushi 410 and 8 pieces of the second sushi 420. In the example shown in FIG. 31, the second sushi 420 having a material portion having a large water content is arranged on the outer peripheral side (that is, the end side) of the circular tray 431, and the first material portion having a material portion having a small water content is arranged. Sushi 410 is placed in the center of tray 431.

(Example)
In the following examples, in the frozen sushi pack 400 composed of the first sushi 410 having a water content of 50% and the second sushi 420 having a water content of 80%, each group Dielectric heating treatment was performed by variously changing the number ratio of sushi, and the finish condition at the end of heating was evaluated. The total number of sushi contained in the frozen sushi pack 400 was 3, 4, 5, 6, 7, 8, 9, 10, 15, and 20.

The results are shown in Tables 1 to 3 below. The criteria for judging the evaluation results shown in each table are as follows.
〇: Optimal, good quality, and quick thawing time.
Δ: Thawing is possible, but the thermal efficiency is poor and it takes some time. Other ingenuity (arrangement, etc.) is required.
×: It can be decompressed somehow, but the result is unstable.
The table below also shows the experimental results for frozen sushi packs consisting only of sushi that belong to the same group. All of these results were also good (○).

From the above results, it is said that the number of the first sushi 410 classified into the first group is in the range of 25% or more and 75% or less of the total number of sushi contained in the frozen sushi pack 400. It was found that the finish was good at the end of thawing.

(How to thaw a frozen sushi pack)
Subsequently, a method of thawing the frozen sushi pack 400 according to the present embodiment will be described. This thawing method can also be applied to frozen sushi packs 400a, 400b, 400c and the like other than frozen sushi pack 400.

The frozen sushi pack 400 can be thawed by a method according to the thawing step of the food manufacturing method described in the fourth embodiment described above. When thawing the frozen sushi pack 400, the frozen sushi pack 400 is thawed by a dielectric heating treatment using a high frequency electric field of HF wave or VHF wave. This thawing method can be carried out, for example, by using the high frequency heating device 100 or 200 described in the first or second embodiment described above as a thawing machine. Specifically, the frozen sushi pack 400 (object to be thawed) is sandwiched between the upper electrode 1a and the lower electrode 1b, and a high-frequency electric field of HF wave or VHF wave is applied between the electrodes to dielectrically heat the frozen sushi pack 400. To do.

When thawing the frozen sushi pack 400, it is preferable to select a rapid thawing method in which thawing is completed in the shortest possible time.

As a rapid thawing method, microwave oven heating is generally used, but this method may cause overheating and uneven heating, and frozen food cannot be thawed with high quality. On the other hand, in the defrosting of VHF waves or HF waves in an electric field by the above-mentioned high-frequency heating device, overheating, uneven heating, drip and the like can be suppressed, and higher quality defrosting can be performed.

Here, an example of the dielectric heating device used for the thawing process of the frozen sushi pack 400 will be described. As described above, the thawing process can be carried out using a high frequency heating device 100 or 200, which is an example of the dielectric heating device according to the present invention.

The high frequency heating devices 100 and 200 include at least two electrodes arranged to face each other (that is, an upper electrode 1a and a lower electrode 1b), and a high frequency power supply 2 that supplies a high frequency electric field by an HF wave or a VHF wave to these electrodes. And a matching circuit 3 and the like are provided.

With this configuration, a high-frequency electric field can be efficiently applied to the frozen sushi pack 400, and high-quality sushi with less temperature unevenness can be obtained in a short time.

Further, the dielectric heating device used for the thawing process may further include a position changing mechanism for changing the position of the electrode. The position changing mechanism is, for example, a movable portion 8 provided in the high frequency heating device 100.

By providing the movable portion 8, the position of the upper electrode 1a can be changed according to the size of the frozen sushi pack 400 during dielectric heating. By appropriately setting the distance between the processed food and the upper electrode 1a, energy can be efficiently applied to the frozen processed food, and the thawing time can be shortened.

The total water content of the plurality of sushi ingredients contained in the frozen sushi pack 400 is the product of the thawing time required to thaw the sushi pack to the desired state and the output power (output wattage) of the thawing machine. Is proportional to. Therefore, it is preferable that the thawing time during the thawing process and the output power of the thawing machine are determined based on the total water content of the sushi material contained in the frozen sushi pack 400.

FIG. 32 shows the total amount of water (g) contained in each sushi material constituting the sushi pack, the thawing time (minutes) required for thawing the sushi pack, the thawing power (W), and thawing. The product of time and thawing power (time x W) is shown. As shown in this figure, the product of thawing time and thawing output is roughly proportional to the total water content of the material contained in the sushi pack.

Therefore, refer to the graph shown in FIG. 32 according to the specifications (for example, set thawing time (minutes) and thawing power (W)) of the thawing machine (for example, high-frequency heating device 100 or 200) used for thawing. Then, it is preferable to determine the composition of the plurality of sushi contained in the frozen sushi pack 400 (for example, the total water content (g) contained in the material of each sushi).

As an example, when a value such as "100W, 5 minutes" is preset in the setting button of the defroster, it is included in each sushi material constituting the sushi pack 400 with reference to the graph of FIG. 32. It is preferable to adjust the water content of the material so that the total water content (g) is about 50 g. By performing a simple operation using the setting button of the defroster, the finish of the sushi after the defrosting can be improved.

Alternatively, a guideline for the thawing time can be determined from the total water content of the material in the frozen sushi pack 400 and the thawing output. In this case, by setting a thawing time suitable for the material, it is possible to reduce overheating and insufficient thawing of the material.

(Other variants)
Hereinafter, other examples of sushi constituting the frozen sushi pack 400 will be described.

The sushi 410 and 420 constituting the frozen sushi pack 400 may contain seaweed as a food ingredient in addition to the sushi portions 411 and 421 and the sushi portions 412 and 422. Further, the first sushi 410 and the second sushi 420 described above have a configuration in which the material portion is arranged on the rice portion, but the arrangement positions of the rice portion and the material portion are not limited to this.

For example, in the case of sushi composed of sushi rice, sushi rice and seaweed, the sushi rice sushi may be located inside the sushi rice sushi and the seaweed may be placed outside the sushi rice. .. Alternatively, the rice sushi portion and the seaweed may be arranged inside the sushi rice portion.

In addition, it is also possible to appropriately change the mixing ratio of the rice sushi portion and the material portion according to the needs of the consumer. Further, the frozen sushi pack according to the present embodiment may be combined with soup to form one frozen food. In this case, for example, the frozen sushi pack is placed above and the soup is placed below. For example, the electrode of the defroster used at the time of thawing, such as the high frequency heating device 100 or 200, is composed of an upper electrode and a lower electrode.

33 to 35 show an example of a frozen sushi pack in which a plurality of containers are stacked one above the other.

The frozen sushi pack 400d shown in FIG. 33 is composed of two containers 430a and 430b stacked one above the other. A plurality of sushi 410s and 420s are arranged in each of the containers 430a and 430b. Similar to the frozen sushi pack 400, the plurality of sushi contained in the frozen sushi pack 400d consists of a first group composed of a first sushi 410 having a small water content and a second sushi 420 having a large water content. It is classified into a second group to be composed.

In the example shown in FIG. 33, in the upper container 430a, the second sushi 420 and the first sushi 410 are alternately arranged in this order from the left side of the tray. In the lower container 430b, each sushi is arranged alternately in the order of the first sushi 410 and the second sushi 420 from the left side of the tray.

By arranging the sushi with different water ratios in the vertical direction in this way, the heat application becomes the same at the top and bottom, and it becomes easy to make the finished temperature uniform. As a result, the composition of the sushi pack can be determined without depending on the type of material, and it becomes easy to satisfy the taste of the consumer.

The frozen sushi pack 400e shown in FIG. 34 is composed of two containers 430a and 430b stacked one above the other. A plurality of sushi 410s and 420s are arranged in the containers 430a and 430b. Similar to the frozen sushi pack 400, the plurality of sushi contained in the frozen sushi pack 400e consists of a first group composed of a first sushi 410 having a small water content and a second sushi 420 having a large water content. It is classified into a second group to be composed.

More specifically, in the upper container 430a, first sushi 410s having a small water content are arranged side by side. Second sushi 420s having a large water content are arranged side by side in the lower container 430b.

In this way, the two containers 430a and 430b in which the sushi with different water ratios are arranged are arranged so as to be stacked in the vertical direction, so that the heat application is equal in the upper and lower parts and the finished temperature is uniform. It becomes easier to make. As a result, the composition of the sushi pack can be determined without depending on the type of material, and it becomes easy to satisfy the taste of the consumer.

The frozen sushi pack 400f shown in FIG. 35 is composed of three containers 430a, 430b, and 430c stacked one above the other. A plurality of sushi 410s and 420s are arranged in each of the containers 430a, 430b, and 430c. Similar to the frozen sushi pack 400, the plurality of sushi contained in the frozen sushi pack 400f consists of a first group composed of a first sushi 410 having a small water content and a second sushi 420 having a large water content. It is classified into a second group to be composed.

More specifically, the second sushi 420 having a large water content is arranged side by side in the uppermost container 430a and the lowermost container 430c. In the middle container 430b, the first sushi 410s having a small water content are arranged side by side.

In this way, the three containers 430a, 430b, and 430c in which the sushi having different water ratios are arranged are arranged vertically in the same order as described above, so that heat is applied vertically. It becomes the same, and it becomes easy to make the finished temperature uniform. As a result, the composition of the sushi pack can be determined without depending on the type of material, and it becomes easy to satisfy the taste of the consumer.

(Summary of the fifth embodiment)
The frozen sushi pack 400 according to the present embodiment is composed of two or more types of sushi (that is, sushi 410 and 420) having different water ratios. The water content (weight) per unit volume of the plurality of sushi 410 and 420 is less than this standard value with the reference value between 55% (weight%) and 65% or less as a boundary. It is classified into a first group having a sushi and a second group in which the material portion has a water content equal to or higher than this reference value. The total weight (for example, the number of grams) of the first sushi 410 classified into the first group is larger than the total weight of the second sushi 420 classified into the second group.

In this way, by making the amount of the material of the first sushi 410, which has a low water content and is easy to heat, larger than the amount of the material of the second sushi 420, which has a high water content and is easy to heat, until the whole sushi is warmed up. It is possible to extend the time of sushi and make the temperature rise of each material uniform.

Further, in the frozen sushi pack 400 according to the present embodiment, the arrangement of each sushi is devised in consideration of the influence of heat propagation between individual sushi. Thereby, for example, the heat generated in the first sushi 410 can be transferred to the adjacent second sushi 420, so that the output of the thawing machine can be efficiently converted into the thawing heat. Therefore, for example, as in the method of Patent Document (Japanese Unexamined Patent Publication No. 10-56995), the optimum amount of sushi material is simply adjusted without using a container containing water at the top of the sushi container. Temperature sushi can be served.

That is, according to the frozen sushi pack 400 according to the present embodiment, it is possible to obtain sushi having a good texture and quality when thawed by dielectric heating thawing without changing the container or adding an operation. Can be done.

Further, according to the frozen sushi pack 400 according to the present embodiment, it is possible to reduce temperature unevenness during thawing without requiring a complicated mechanism or control on the thawing machine side. Further, since the temperature at the time of thawing can be controlled to some extent by the configuration of the frozen sushi pack 400, the thawing time can be unified, the operation of the thawing machine can be simplified, and the control sequence can be simplified.

By devising the composition and arrangement of sushi by paying attention to the water content of each material, the composition of the sushi pack can be determined without depending on the type of material. Therefore, it is possible to compose a sushi pack using a wide variety of ingredients, and it is possible to satisfy the appetite of consumers. In addition, since the temperature of the sushi rice and the ingredients can be adjusted, the texture can also be controlled, and the choice of texture can be increased according to the taste of the consumer.

[Sixth Embodiment]
Subsequently, the sixth embodiment of the present invention will be described. In the sixth embodiment, the frozen sushi set according to one aspect of the present invention will be described. Here, as an example of a frozen sushi set, a frozen sushi pack (assorted sushi) composed of a plurality of sushi will be described as an example. This frozen sushi pack is thawed by dielectric heating treatment with a high frequency electric field of HF wave or VHF wave.

In the present embodiment, attention is paid to the height of each sushi constituting the frozen sushi pack, and the arrangement of sushi in the container is appropriately adjusted based on the height of each sushi. In addition, the ratio of water content and the ratio of mass density between each sushi are adjusted based on the ratio of the height between the sushi. As a result, the frozen sushi pack according to the present embodiment becomes a sushi pack having a good texture and quality by the thawing treatment by dielectric heating.

(About the height and temperature unevenness of the object to be heated)
In explaining the configuration of the frozen sushi pack according to the present embodiment, first, the temperature unevenness caused by the difference in the height of the object to be heated (that is, sushi), which is a premise thereof, will be described.

As shown in FIG. 36, objects A to be heated having heights d1 and d2 (d1> d2) having substantially the same dielectric constant are arranged between the flat plate electrodes (1a and 1b) arranged in parallel at a distance L. When a voltage V is applied between the flat electrode, the voltages applied to both objects A to be heated are V1 and V2. At this time, since the electrolytic strengths in both objects A to be heated are voltage / height, they are (V1 / d1) and (V2 / d2), respectively, and the relationship of (V1 / d1)> (V2 / d2). Holds. In dielectric heating, the larger the electric field strength, the easier it is to heat, so the object A to be heated with a height d1 tends to be heated more easily. That is, temperature unevenness is likely to occur between objects to be heated having heights d1 and d2.

Similarly, when the object A to be heated is sushi, the higher the height of the sushi, the faster the heating is performed when the dielectric heating is performed between the parallel flat plate-shaped upper electrodes 1a and the lower electrodes 1b. That is, when sushi with different heights is thawed by dielectric heating at the same time, the temperature of tall sushi rises faster, resulting in temperature unevenness between each sushi.

(Composition of frozen sushi pack 500)
FIG. 37 shows an example of the frozen sushi pack 500 of this embodiment. The frozen sushi pack 500 is mainly composed of a container 530 and a plurality of sushi 510 and 520. The container 530 has a tray 531 and an upper lid 532. The individual sushi 510 and 520 have a sushi portion 512 or 522 and a material portion 511 or 521 arranged on the sushi portion.

The rice sushi portion 512 or 522 is composed of vinegared rice. However, in another example, the rice portion may be cooked rice such as white rice or millet rice. The material portion 511 or 521 is composed of, for example, seafood. However, the material portion is not limited to seafood, and may be ingredients such as vegetables, mushrooms, algae, and meat. In addition, processed ingredients such as seafood tempura, grilled egg, mackerel, ribs, and hamburger may be used.

The plurality of sushi 510 and 520 are arranged side by side on the tray 531 of the container 530. The plurality of sushi 510 and 520 have a first group having a height higher than the predetermined reference value and a second group having a height equal to or lower than the predetermined reference value, with the predetermined reference value as a boundary. It is classified into the group of. As described above, the plurality of sushi 510 and 520 constituting the frozen sushi pack 500 according to the present embodiment are composed of at least two types having different heights.

The height of each sushi is calculated by the vertical distance from the surface of the tray 531 of the container 530 to the upper surface of the sushi. The height of each sushi is the sum of the height of the rice sushi and the height of the sushi. Therefore, even if the rice sushi rice has the same height, the height of the sushi can be different due to the difference in the height of the sushi rice. In addition, even if the sushi has the same material, there may be a difference in height between the sushi due to the difference in the size of each material.

In the present embodiment, the sushi classified into the first group (that is, relatively tall sushi) is referred to as the first sushi 510. Further, the sushi classified into the second group (that is, relatively short sushi) is referred to as the second sushi 520.

The classification of sushi into the first group and the second group is performed with a predetermined reference value as a boundary. The predetermined reference value can be determined based on any selection criteria. For example, the average value of the heights of all the sushi constituting the frozen sushi pack 500 can be set as a predetermined reference value. Alternatively, the ratio to the distance between the two plate electrodes (for example, the upper electrode 1a and the lower electrode 1b) of the defroster used during the thawing process (for example, an arbitrary value of 50% to 70% of the distance D between the electrodes, etc.) Specifically, 60% of the distance D between the electrodes) can be set as a predetermined reference value. Alternatively, the predetermined reference value can be about 80% (any value between 75% and 85%) of the height dmax of the tallest sushi.

In the frozen sushi pack 500 according to the present embodiment, the arrangement of the sushi 510 and 520 having different heights is determined according to the height difference. When the tall groups (that is, the first group) and the short groups (that is, the second group) are arranged together, the tall groups of sushi are separated from each other. Alternatively, heat conduction does not occur between low-height groups of sushi. Therefore, the temperature of the sushi in the frozen sushi pack as a whole is uneven.

In the frozen sushi pack 500 according to the present embodiment, as shown in FIG. 38, the first sushi 510 having a high height and the second sushi 520 having a low height are alternately arranged when viewed from above. Since each sushi is adjacent to sushi with different heights on the long side, heat conduction that contributes to temperature equalization between sushi is promoted, and temperature unevenness during thawing is reduced.

An example of alternately arranging the first sushi 510 and the second sushi 520 includes an arrangement such as the frozen sushi pack 500a shown in FIG. 28. In the example shown in FIG. 28, the first sushi 510 and the second sushi 520 are arranged in a staggered pattern. In such an arrangement, in addition to the long side surface of each sushi, the short side surface is adjacent to the sushi having different heights, so that the contact area between the sushi with different temperatures can be further increased. Therefore, heat conduction that contributes to temperature equalization between each sushi is further promoted, and temperature unevenness is reduced. In addition, the overall appearance of the sushi is improved.

Further, an example in which the first sushi 510 and the second sushi 520 are alternately arranged includes an arrangement such as the frozen sushi pack 500b shown in FIG. 39. In the example shown in FIG. 39, when the frozen sushi pack 500b is viewed from above, each sushi is arranged diagonally with respect to the shape of the tray 531 and the first sushi 510 and the second sushi 520 are arranged alternately. To do. Placing each sushi diagonally has the effect of reminiscent of the image of high-class assorted sushi. Moreover, since each sushi is adjacent to sushi having different heights on the long side, heat conduction that contributes to temperature equalization between the sushi is promoted, and temperature unevenness is reduced.

Further, an example in which the first sushi 510 and the second sushi 520 are alternately arranged includes an arrangement such as the frozen sushi pack 500c shown in FIG. 40. In the example shown in FIG. 40, two containers 530a and 530b are arranged one above the other in two stages. The arrangement of each sushi arranged on the trays 531a and 531b of the containers 530a and 530b is a staggered arrangement as shown in FIG. 28. When any one of the two trays 531a and 531b is rotated 180 degrees, the figure on the right side of FIG. 40 is obtained. When these are stacked in two layers as shown in the figure on the left, the tall first sushi 510 and the short second sushi 520 overlap vertically, and the total height of the two overlapping sushi pieces is in any place. The same applies to. Therefore, temperature unevenness between each sushi during thawing is reduced.

(About temperature unevenness in the object to be heated)
Subsequently, the temperature unevenness that may occur inside the object to be heated during dielectric heating will be described with reference to FIG. 41. When a heated object A having a height d is arranged between the plate electrodes arranged in parallel at a distance L and a voltage V is applied between the plate electrodes, the voltage applied to the heated object A is V ″, and the heated object A The voltage at the height d in the region where there is no air and only air is V', and V "<V'. At this time, in the vicinity of the corners of the upper surface of the object to be heated, in addition to the vertical electric field due to the voltage between the electrodes, a horizontal electric field is generated due to the horizontal potential difference (V'-V "), so that the electric fields are concentrated. As a result, it is more likely to be heated than other parts of the object to be heated. That is, it is likely to cause temperature unevenness when placed in the object to be heated.

When multiple sushi pieces in a frozen sushi pack are viewed as one lump, both ends of the sushi are easily heated. Therefore, when multiple sushi pieces are lined up, the sushi placed at both ends is easily heated. .. Further, in the case of the arrangement as shown in FIG. 37, the first sushi 510 having a high height is arranged at the right end, and the sushi that is easily heated is arranged in a place that is easily heated. Therefore, the temperature of the sushi on the right end is promoted as compared with other sushi, and the temperature unevenness of the sushi as a whole is promoted.

(Composition of frozen sushi pack 550)
An example of arranging sushi with different height differences with the intention of reducing the occurrence of such temperature unevenness will be described below. As described above, when the tall sushi is placed at the end of the whole sushi, it becomes extremely easy to be heated, and the temperature unevenness of the whole sushi in the sushi pack tends to occur.

Therefore, it is preferable that the first sushi 510 classified into the first group is arranged in the central portion on the tray 531. Further, the second sushi 520 classified into the second group is preferably arranged on the outer peripheral portion (end portion) on the tray 531.

Examples of such an arrangement include an arrangement such as the frozen sushi pack 550 shown in FIG. 29. In this arrangement example, each sushi is arranged so that the side surface on the long side side of the second sushi 520 having a rectangular parallelepiped shape is located at the end. As a result, the area of the side surface of the second sushi 520 located on the end side of the tray 531 becomes larger than the area of the side surface of the first sushi 510 also located on the end side of the tray 531. That is, when viewed as a whole sushi set, the second sushi 520, which is difficult to heat, constitutes more ends.

When the number of sushi is larger than that of the frozen sushi pack 550 and the proportion of the second sushi 520 having a lower height is large, an arrangement like the frozen sushi pack 550a shown in FIG. 30 is also possible. In this way, by arranging the second sushi 520 having a low height on the outer peripheral portion where it is easily heated, it is possible to reduce the temperature unevenness of the sushi as a whole.

When the proportion of the second sushi 520 is small, the second sushi 520 is arranged at the corners (specifically, the four corners) on the tray 531 as in the frozen sushi pack 550a shown in FIG. 42. It is better to do it. When thawing a frozen sushi pack, the outer peripheral portion of the container is likely to be heated, but among them, the electric field strength at the four corners of the tray is particularly large, and the frozen sushi pack tends to be easily heated. Therefore, by arranging the few second sushi 520s at the four corners, the temperature unevenness of the sushi as a whole can be reduced.

In addition, examples of arranging the second sushi 520 at the corners on the tray 531 also include arrangements such as the frozen sushi packs 550b and 550c shown in FIGS. 43 and 44. In the example shown in FIG. 43, each sushi is arranged diagonally with respect to the shape of the tray 531 when viewed from the upper surface, and the second sushi 520 having a low height is arranged at the upper right and the lower left in the figure. The frozen sushi pack 550c shown in FIG. 44 is an example in which each sushi is arranged diagonally with respect to the shape of the tray 531 when the number of the first sushi 510 and the number of the second sushi 520 are the same. Placing each sushi diagonally has the effect of reminiscent of the image of high-class assorted sushi. In addition, since the sushi that is low in height and difficult to heat is placed in the area where it is easy to heat, the temperature unevenness of the sushi as a whole is reduced.

When the sushi is arranged in close contact with each other, even if the arrangement of the sushi is devised, the portion that does not correspond to the outer peripheral portion (for example, in FIG. 43, the central portion of the 6 pieces of the tall first sushi 510). (Sushi located in) is difficult to heat, which causes temperature unevenness of the sushi as a whole. Therefore, by arranging the sushi at intervals, it is possible to make the electric field concentration occur on the outer circumference of each sushi. This reduces the temperature unevenness of the sushi as a whole.

(How to adjust the height of sushi)
Subsequently, a method of adjusting the height of a plurality of sushi constituting the frozen sushi packs 500 and 550 will be described. In the frozen sushi packs 500 and 550 according to the present embodiment, the height dm of the sushi having the lowest height among the plurality of sushi constituting the sushi pack is 60% or more of the height dmax of the sushi having the highest height. Is preferable (see FIG. 48).

Regarding the regulation of the height of sushi, a verification experiment conducted by the inventors of the present application will be described.

In the verification experiments by the inventors, a 5 cm high container 530 contained a gunkanmaki (dmax = 4 cm) as the tallest sushi, and a squid sushi (dmin = 2.5 cm) as the lowest sushi. ), A frozen sushi pack 500 composed of a total of 9 pieces of sushi 510 and 520 was subjected to dielectric heating treatment using a thawing machine with an electrode-to-electrode distance D = 5 cm. As a result, it was confirmed that all sushi can be thawed without uneven heating.

At this time, the height of the squid grip (dmin = 2.5 cm) is about 60% (62.5%) with respect to the height of the warship winding (dmax = 4 cm).

Here, the energy ratio per unit area of sushi at the time of the verification experiment is obtained. As shown in FIG. 45, the distance between the electrodes at the time of the verification experiment is D, and the height of the object to be heated A (that is, sushi) is d. Further, as an electric equivalent circuit having this configuration, as shown in FIG. 46, the capacitance in the space region is C1, and the capacitance in the sushi portion is C2.

First, assuming that the voltage between the electrodes is 1, and the voltage applied to the object to be heated A having a height d is V (d), V (d) is expressed by the following equation.
V (d) = C1 / (C1 + C2)
= {Ε ₀ · S / (D−d)} / [ε ₀ · S · {1 / (D−d) + ε _r / d}]
= D / {d + ε _r · (D−d)}
S: Area of sushi seen from above
ε _r : Relative permittivity (ice: 4)

From this, the electric field strength E (d) inside the object to be heated A is represented by the following formula (A).
E (d) = V (d) / d
= 1 / {d + ε _r · (D−d)} ・ ・ ・ (A)
The energy per unit region inside the electric field strength E (d) is generally expressed by the following equation.
P (d) = K ・ ε _r・ tan δ ・ f ・ E (d) ²
K: Constant 0.556 × 10 ^-10
tan δ: Dissipation factor
f: frequency

When calculating the energy inside sushi _{, assuming that ε r} , tan δ, and f are constant,
P (d) = K'・ E (d) ² ... (B)
It can be expressed as.

Next, using the formulas (A) and (B), the ratio of the energy per unit region of the sushi of the height d2 to the energy per unit region of the sushi of the height d1 at the distance D between the electrodes is calculated. It is defined as the following equation.
% P (D, d1, d2) = P (d2) / P (d1) · 100
= [{D1 + ε _r · (D−d1)}
_{/ {D2 + ε r · (} D-d2)} ] ^2-100
・ ・ ・ ・ (C)

Substituting the distance between the electrodes D = 5 cm, the height of the tallest sushi d1 = dmax = 4 cm, and the height of the shortest sushi d2 = dm = 2.4 cm (60% of 4 cm) into equation (C). , The energy ratio is about 40%, as shown below.
% P (5,4,2.4) = 39.1
That is, if the energy ratio per unit area inside the sushi is 40% or more, it is possible to realize thawing of a frozen sushi pack that avoids uneven heating.

FIG. 47 is a graph in which D = 5 cm, d1 = dmax = 0.5 to 4 cm, and d2 = dmin = 0.6 · dmax (60% of dmax) are substituted into the formula (C).

For example, in a frozen sushi pack 500 (the container is not shown) composed of sushi having different heights as shown in FIG. 48, the maximum sushi height dmax is 4 cm or less (for example, for a distance D = 5 cm between electrodes). If the minimum sushi height dmin is 60% or more of the maximum sushi height dmax (for example, 60% of 3 cm is 1.8 cm), the energy rate per unit area inside the sushi is 40% or more. It becomes. As a result, a frozen sushi pack that avoids uneven heating during thawing can be realized.

Considering the shape of the tray 531 of the container 530 and the space distance between the upper lid 532 and the material portion, the height of sushi can be practically less than 80% of the distance between the electrodes. That is, assuming that the distance D between the electrodes is 5 cm, the maximum height that the container 530 of the frozen sushi pack 500 can take is 5 cm. Of the sushi arranged in such a container 530, the height of the tallest sushi is usually 4 cm or less.

Assuming that the maximum sushi height exceeds 4 cm and the minimum sushi height is 60% of the maximum sushi height and applied to the formula (C), the energy ratio per unit area inside the sushi is 40% or less. However, considering the shape of the tray of the container and the space distance between the upper lid and the material portion, the height of the sushi is practically 4 cm or less, that is, less than 80% of the distance D between the electrodes. In this case, since the energy ratio does not fall below 40%, practically, the lower limit of the height difference between the sushi may be 60%.

As described above, among the plurality of sushi constituents of the sushi pack, the height dm of the sushi with the lowest height is 60% or more of the height dmax of the sushi with the highest height. It is possible to avoid heating unevenness due to the height difference. Therefore, in the frozen sushi packs 500 and 550 according to the present embodiment, the degree of freedom in arranging the sushi having different heights constituting the sushi pack is increased. Further, by applying various arrangement examples of each sushi described in the present embodiment while satisfying the condition of dm in ≧ 0.6 · dmax, it is possible to further reduce the heating unevenness at the time of thawing.

(About the relationship between the height of sushi and the water content)
Next, the relationship between the height of each sushi constituting the frozen sushi packs 500 and 550 and the water content of each sushi will be described.

As described above, the ease of heating each sushi constituting the frozen sushi pack at the time of thawing is affected not only by the height of the sushi but also by the amount of water contained in the sushi. That is, even when the height difference of each sushi is large, if the difference in the water content of each sushi is small, theoretically, uneven heating during thawing is unlikely to occur.

Therefore, for example, the water content of the sushi rice with a high height is increased, and the water content of the rice sushi with a low height is reduced. That is, the amount of water per unit volume of the material portion 511 of the first sushi 510 classified in the first group is the amount of water per unit volume of the material portion 521 of the second sushi 520 classified in the second group. It is preferable to increase the amount of water. Alternatively, the water content of the rice may be changed in consideration of the water content depending on the type of material. By doing so, it is possible to reduce uneven heating during thawing of the frozen sushi pack.

Here, let d be the height of each of the plurality of sushi constituting the frozen sushi pack 500, and let B be the water content ratio (water content per unit volume) of each of the plurality of sushi. At this time, if the ratio of the water content ratio B to the height d is C (that is, B / d) in each sushi, the minimum value Cmin of the ratio C is 60% or more of the maximum value Cmax of the ratio C. It is preferable to have.

Here, if the height of high-height sushi is dH, the water content is BH, the height of low-height sushi is dL, and the water content is BL, the frozen sushi pack that avoids uneven heating can be thawed. In order to realize this, it is preferable to satisfy the following formula (D).
[{P (dL) / BL} / {P (dH) / BH}] · 100
=% P (D, dH, dL) · (BH / BL) ≧ 40 ... (D)

However, when making a frozen sushi pack that can be thawed well, it is complicated to actually refer to the formula (D). Therefore, instead of% P (D, dH, dL) shown by the solid line in FIG. 49, the sushi height and the energy ratio inside the sushi are approximated by a proportional straight line passing through the origin, as shown by% P'shown by a broken line. As a result, it is simplified to the following formula (E).
% P'・ (BH / BL) = (dL / dH) ・ (BH / BL) ・ 100 ・ ・ ・ (E)

Under the same conditions of water content BL and BH of each sushi,
BH / BL = 1
And (dL / dH) ・ 100 ≧ 60
Is. Therefore, the following equation (F) is derived.
% P'・ (BH / BL) = (dL / dH) ・ (BH / BL) ・ 100
= (DL / BL) / (dH / BH) ・ 100 ≧ 60 ・ ・ ・ (F)

here,
(DL / BL) = Cmin, (dH / BH) = Cmax
Substituting with, the following equation (G) is obtained.
Cmin / Cmax ≧ 60 ・ ・ ・ (G)
By adjusting the sushi height and the water content so as to satisfy this formula (G), the degree of freedom of arrangement is increased from the viewpoint of avoiding heating unevenness caused by the height difference of sushi.

(Relationship between sushi height and mass density)
Next, the relationship between the height of each sushi constituting the frozen sushi packs 500 and 550 and the mass density of each sushi will be described.

As described above, the ease of heating each sushi constituting the frozen sushi pack at the time of thawing is affected not only by the height of the sushi but also by the amount of water contained in the sushi. However, it can be difficult to measure the actual water content of each sushi. Therefore, it is also possible to use the mass density that correlates with the water content as an index of the ease of heating when thawing each sushi.

Here, let d be the height of each of the plurality of sushi constituting the frozen sushi pack 500, and let ^{G be the mass density of each of the plurality of sushi (mass per unit volume (g / cm 3} )). At this time, in each sushi, assuming that the ratio of the mass density G to the height d is H (that is, G / d), the minimum value Hmin of the ratio H is 60% or more of the maximum value Hmax of the ratio H. Is preferable.

Specifically, assuming that the height of high-height sushi is dH and the mass density is GH, the height of low-height sushi is dL, and the mass density is GL, the frozen sushi pack is thawed to avoid uneven heating. Is preferably satisfied by the following formula (H).
% P'・ (GH / GL) = (dL / dH) ・ (GH / GL) ・ 100
= (DL / GL) / (dH / GH) ・ 100 ≧ 60 ・ ・ ・ (H)

here,
(DL / GL) = Hmin, (dH / GH) = Hmax
Substituting with, the following equation (I) is obtained.
Hmin / Hmax ≧ 60 ・ ・ ・ (I)
^{By adjusting the sushi height and mass density (g / cm 3} ) so as to satisfy this formula (I), the degree of freedom of arrangement is increased from the viewpoint of avoiding heating unevenness due to the height difference of sushi. ..

(How to thaw a frozen sushi pack)
Subsequently, a method of thawing the frozen sushi pack 500 according to the present embodiment will be described. This thawing method can also be applied to frozen sushi packs 500a and 550 other than frozen sushi pack 500.

The frozen sushi pack 500 can be thawed by a method similar to the thawing step of the food manufacturing method described in the fourth embodiment above, similarly to the frozen sushi pack 400 according to the fifth embodiment. When thawing the frozen sushi pack 500, the frozen sushi pack 500 is thawed by a dielectric heating treatment using a high frequency electric field of HF wave or VHF wave. This thawing method can be carried out, for example, by using the high frequency heating device 100 or 200 described in the first or second embodiment described above as a thawing machine. Specifically, the frozen sushi pack 500 (object to be thawed) is sandwiched between the upper electrode 1a and the lower electrode 1b, and a high-frequency electric field of HF wave or VHF wave is applied between the electrodes to dielectrically heat the frozen sushi pack 500. To do.

When thawing the frozen sushi pack 400, it is preferable to select a rapid thawing method in which thawing is completed in the shortest possible time. As a rapid thawing method, microwave oven heating is generally used, but this method may cause overheating and uneven heating, and frozen food cannot be thawed with high quality. On the other hand, in the defrosting of VHF waves or HF waves in an electric field by the above-mentioned high-frequency heating device, overheating, uneven heating, drip and the like can be suppressed, and higher quality defrosting can be performed.

Here, an example of the dielectric heating device used for the thawing process of the frozen sushi pack 500 will be described. As described above, the thawing process can be carried out using a high frequency heating device 100 or 200, which is an example of the dielectric heating device according to the present invention.

The high-frequency heating devices 100 and 200 include at least two electrodes (that is, an upper electrode 1a and a lower electrode 1b) arranged to face each other, and a high-frequency power source 2 that supplies a high-frequency electric field by an HF wave or a VHF wave to these electrodes. , And a matching circuit 3 and the like.

With this configuration, a high-frequency electric field can be efficiently applied to the frozen sushi pack 500, and high-quality sushi with less temperature unevenness can be obtained in a short time.

Further, the dielectric heating device used for the thawing process may further include a position changing mechanism for changing the position of the electrode. The position changing mechanism is, for example, a movable portion 8 provided in the high frequency heating device 100.

By providing the movable portion 8, the position of the upper electrode 1a can be changed according to the size of the frozen sushi pack 500 during dielectric heating. By appropriately setting the distance between the processed food and the upper electrode 1a, energy can be efficiently applied to the frozen processed food, and the thawing time can be shortened.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims. In addition, a configuration obtained by combining the configurations of different embodiments described in the present specification with each other is also included in the scope of the present invention.

1a: Upper electrode (electrode plate)
1b: Lower electrode (electrode plate)
2: High frequency power supply 3: Matching circuit 3a: Variable capacitor (variable reactance element)
3b: Variable capacitor (variable reactance element)
4: Reading unit (discriminating unit)
5: Memory (storage unit)
6: Control circuit (control unit)
7: Operation unit (input unit)
8: Movable part (position change mechanism)
100: High frequency heating device (dielectric heating device)
200: High frequency heating device (dielectric heating device)
300: Frozen sushi (frozen food)
301: Neta part (upper layer part)
302: Rice sushi rice (lower layer)
400: Frozen sushi pack (frozen sushi set)
410: First sushi 411: Neta section 412: Shari section 420: Second sushi 421: Neta section 422: Shari section 430: Container 431: Tray 500: Frozen sushi pack (frozen sushi set)
510: First sushi 511: Neta part 512: Shari part 520: Second sushi 521: Neta part 522: Shari part 530: Container 531: Tray

Claims (8)

A frozen sushi set that is thawed by dielectric heating with a high-frequency electric field of HF or VHF waves.
Including a container and a plurality of sushi arranged in the container,
The sushi has a sushi portion and a material portion arranged on the sushi portion.
The plurality of sushi is composed of at least two types of sushi having different heights.
Frozen sushi set. The plurality of sushi
The first group whose height is higher than the predetermined value and
It is classified into a second group whose height is equal to or less than the predetermined value.
In the container, the sushi classified into the first group and the sushi classified into the second group are alternately arranged.
The frozen sushi set according to claim 1. The plurality of sushi
The first group whose height is higher than the predetermined value and
It is classified into a second group whose height is equal to or less than the predetermined value.
The sushi classified into the first group is located in the center of the container.
The frozen sushi set according to claim 1 or 2. The plurality of sushi
The first group whose height is higher than the predetermined value and
It is classified into a second group whose height is equal to or less than the predetermined value.
The sushi classified into the second group is arranged at the corner of the container.
The frozen sushi set according to any one of claims 1 to 3. The method according to any one of claims 1 to 4, wherein the height dm of the sushi having the lowest height among the plurality of sushi is 60% or more of the height dmax of the sushi having the highest height. Frozen sushi set. Let d be the height of each of the plurality of sushi.
Let B be the water content of each of the plurality of sushi.
In each sushi, assuming that the ratio of the water ratio B to the height d is C,
The frozen sushi set according to any one of claims 1 to 5, wherein the minimum value Cmin of the ratio C is 60% or more of the maximum value Cmax of the ratio C. Let d be the height of each of the plurality of sushi.
Let G be the mass density of each of the plurality of sushi.
In each sushi, let H be the ratio of mass density G to height d.
The frozen sushi set according to any one of claims 1 to 6, wherein the minimum value Hmin of the ratio H is 60% or more of the maximum value Hmax of the ratio H. The plurality of sushi
The first group whose height is higher than the predetermined value and
It is classified into a second group whose height is equal to or less than the predetermined value.
The water content per unit volume of the material portion of the sushi classified in the first group is larger than the water content per unit volume of the material portion of the sushi classified in the second group. The frozen sushi set according to any one of claims 1 to 7.

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