Method for thawing frozen sushi and thawing appliance set

Abstract

This appliance for thawing frozen sushi is characterized in that the appliance has a tray on which frozen sushi can be set with the frozen rice facing downwards, steam, water vapor, or vapor can be brought into contact with the bottom of the rice from a hole provided in the tray when thawing the frozen sushi, and the periphery of the tray is opened to outside air when thawing the frozen sushi.

Description

Technical Field

[0001] The present disclosure relates to at least one of an apparatus for thawing frozen sushi, food with the apparatus, a thawing device for frozen sushi, or a method for thawing frozen sushi.

Background Art

[0002] Frozen sushi (hereinafter also simply referred to as "frozen sushi") mainly comprises two parts: cooked rice and sushi ingredients (hereinafter also referred to as "sushi topping" or simply "topping"). For example, frozen Edomae sushi generally has a form in which frozen sushi topping is placed on top of frozen cooked rice. Here, it is known that when the frozen cooked rice is thawed by a slow method such as natural thawing, a phenomenon called "Hakurou Phenomenon" occurs. Hakurou Phenomenon refers to a phenomenon in which moisture disappears from the rice and it becomes lumpy like wax, and the cooked rice with Hakurou Phenomenon has a significantly reduced taste. It is considered that the Hakurou Phenomenon occurs due to the combined action of starch aggregation when the cooked rice is thawed and starch aging when the cooked rice is left at a low temperature.

[0003] In order to eliminate such a Hakurou Phenomenon, there is known a method for thawing frozen sushi in which the frozen sushi is heated using electromagnetic waves so that the temperature of the cooked rice part of the frozen sushi composed of the cooked rice part and the ingredient part is 60 to 95°C and the temperature of the ingredient part is -2 to 20°C, and then this heating is stopped (Claims 1 and 2 of Patent Document 1).

[0004] In addition, Patent Document 2 discloses a technique of individually packaging cooked rice (the part referred to as "rice balls" in Patent Document 2, also called "rice ball") and sushi ingredients in order to individually thaw them. In Patent Document 2, the cooked rice is thawed by a microwave oven, and the sushi ingredients are thawed by running water (paragraph

[0033] of Patent Document 2). Furthermore, Patent Document 3 discloses a technique related to a double container for storing frozen nigiri sushi that enables the frozen nigiri sushi to be heated by pouring hot water, and a frozen nigiri sushi storage using the same (paragraph

[0001] of Patent Document 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when using a microwave oven as in Patent Documents 1 and 2, there is a problem that frozen sushi cannot be thawed without a microwave oven and a power source. In addition, when thawing frozen sushi using a microwave oven, since the whole sushi is generally irradiated with microwaves, it is difficult to individually control the temperature of the cooked rice and the sushi ingredients.

[0007] In addition, in Patent Document 2, since the cooked rice and the sushi ingredients are individually packaged and thawed, the packaging cost increases and the labor for thawing increases. In particular, thawing the sushi ingredients with running water not only takes time and labor but also requires a large amount of water, increasing the environmental burden. Furthermore, in the method of Patent Document 2, it is necessary to place the sushi ingredients on top of the cooked rice after thawing, which not only increases the labor but also requires the sushi provider or eater to have the skill of making sushi.

[0008] On the other hand, in the thawing method by pouring hot water described in Patent Document 3, it takes time to thaw the frozen sushi, or there is a risk that the thawing of the frozen sushi will be insufficient. In particular, in a thawing method such as that of Patent Document 3, which has no heat source and the hot water temperature decreases over time, it can be said that there is a high risk that it takes time to thaw the frozen sushi or the thawing of the frozen sushi will be insufficient. Furthermore, in Patent Document 3, since hot water needs to be prepared for soaking and draining of the hot water is required after thawing, not only does the labor increase, but equipment for preparing and discarding the hot water is also required.

[0009] For thawing of frozen sushi, it is desirable to heat and thaw the rice rapidly and sufficiently, while it is desirable to heat and thaw the sushi ingredients slowly. For example, if the sushi ingredients are heated rapidly, the sushi ingredients that are supposed to be raw will be overheated, and the sushi ingredients will be boiled or burned, and the original taste, flavor or texture of the sushi ingredients cannot be reproduced. Thus, when thawing frozen sushi, it is an issue to adopt a thawing method that is contrary for the rice and the sushi ingredients, in other words, a thawing method that does not impair the texture of each of the rice and the sushi ingredients. Furthermore, as a method of thawing, it is an issue to develop a technique that can thaw frozen sushi simply or rapidly.

[0010] Therefore, an object of the present disclosure is to solve at least one of the above-described problems.

Means for Solving the Problems

[0011] To achieve the above object, in one embodiment, the present disclosure provides an apparatus for thawing frozen sushi, the apparatus having a tray on which the frozen sushi can be placed with the frozen rice on the bottom surface, and when thawing the frozen sushi, it is possible to apply steam, water vapor or hot water vapor from holes provided in the tray to the bottom surface, and when thawing the frozen sushi, the periphery of the tray is open to the outside air.

[0012] According to the above-described appliance, by using steam or the like for thawing frozen sushi, an effect can be achieved in that the texture of the rice and the sushi ingredients are not impaired, and the frozen sushi can be thawed simply or quickly.

[0013] Furthermore, as one embodiment, the present disclosure provides an appliance, characterized in that a guide indicating a position where the frozen sushi is to be placed is provided on the tray.

[0014] According to the above-described appliance, an effect can be achieved in that the installation position of the frozen sushi is guided, making it easy to place the frozen sushi on the tray.

[0015] Furthermore, as one embodiment, the present disclosure provides an appliance, characterized in that uneven portions are provided on a portion of the tray where the frozen sushi is placed. Furthermore, as one embodiment, the present disclosure provides an appliance, characterized in that a mesh portion through which steam, water vapor, or hot steam can pass is provided on a portion of the tray where the frozen sushi is placed.

[0016] According to these above-described appliances, an effect can be achieved in that it is possible to prevent the thawed rice from adhering to the tray 11, or it is considered that it becomes easier to apply steam or the like relatively uniformly to the rice of the frozen sushi SS.

[0017] Furthermore, as one embodiment, the present disclosure provides a food product with an appliance, characterized in that it includes the appliance disclosed by the present disclosure and the frozen sushi installed on the tray of the appliance.

[0018] Furthermore, as one embodiment, the present disclosure provides a thawing device for frozen sushi, characterized in that it includes the appliance disclosed by the present disclosure and a device for generating steam, water vapor, or hot steam. Furthermore, as one embodiment, the present disclosure provides a thawing device for frozen sushi, wherein the steam, water vapor, or hot steam generating device includes a reaction container for reacting a heating material with water to generate the steam, water vapor, or hot steam.

[0019] Furthermore, the present disclosure provides a method for thawing frozen sushi, the method including applying steam, water vapor, or hot steam onto the lower surface of the frozen sushi placed on a tray of an instrument for thawing the frozen sushi, with the frozen sushi having the frozen rice on the lower surface and the periphery of the tray being open to the outside air through holes provided in the tray.

[0020] According to the above method, by using steam or the like for thawing frozen sushi, an effect can be achieved, for example, that the texture of the rice and the sushi ingredients is not impaired, and the frozen sushi can be thawed simply or quickly.

Brief Description of the Drawings

[0021]

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Embodiments for Carrying Out the Invention

[0022] The present disclosure is an apparatus for thawing frozen sushi, the apparatus having a tray on which the frozen sushi can be placed with the frozen rice on the lower surface, and when thawing the frozen sushi, steam, water vapor or hot steam can be applied to the lower surface through through-holes (hereinafter simply referred to as holes) provided in the tray, and when thawing the frozen sushi, the periphery of the tray is open to the outside air.

[0023] As described above, when thawing frozen sushi, while there is a desire to rapidly heat and thaw the rice, there is also a desire to thaw the sushi ingredients placed on top of the rice slowly or at a temperature lower than the thawing temperature of the rice. The difficulty in developing a thawing method that can thaw frozen sushi well, that is, a method that enables the production of sushi with excellent taste and texture, lies in the fact that for frozen sushi having a form in which frozen sushi ingredients are placed on (in contact with) frozen rice, the frozen rice at the bottom needs to be thawed by rapid heating (or thawing at a high temperature), and the sushi ingredients at the top need to be thawed slowly (or thawed at a low temperature). In the prior art, it was impossible or difficult to achieve this contradictory thawing method at once. However, the inventors have conducted intensive studies to achieve this contradictory thawing method.

[0024] In the process of the above studies, the inventors have found that instead of using the conventional method of using a microwave oven (electromagnetic wave), by using steam, water vapor or steam (hereinafter, "steam, water vapor or steam" may also be collectively referred to as "steam, etc."), and applying (exposing) steam, etc. from the lower surface of the frozen sushi, that is, the lower surface of the frozen rice, in other words, the surface opposite to the surface on which the sushi ingredients are placed, a certain amount of heat is applied to the frozen rice to rapidly thaw it. At the same time, by opening the surroundings of the frozen sushi to the outside air during thawing, the heat generated by thawing the frozen rice can easily escape to the surroundings, thereby delaying the thawing of the sushi ingredients and achieving the above contradictory thawing method. In this thawing method, steam, etc. serves as a heat source for the frozen sushi. Since there are gaps between the rice grains in the frozen rice, the thawing of the frozen rice is carried out as the steam, etc. passes through these gaps, and at the same time, the heat of thawing also escapes to the surroundings through these gaps. Therefore, by opening the surroundings during the thawing of the frozen sushi, the effect of easily escaping the steam heat is achieved, making it easier to thaw without damaging the sushi ingredients.

[0025] In order to implement the above-described opposite thawing methods, the apparatus for thawing frozen sushi in the present disclosure has a tray on which the frozen rice of the frozen sushi can be placed with the frozen rice on the lower surface. When thawing the frozen sushi, it is possible to apply steam, water vapor, or hot steam from the holes provided in the tray to the lower surface, and when thawing the frozen sushi, the periphery of the tray is opened to the outside air.

[0026] Hereinafter, an apparatus for thawing frozen sushi, a food with the apparatus, a thawing device for frozen sushi, or a thawing method for frozen sushi according to an embodiment of the present disclosure will be described. FIG. 1 is a perspective view showing an apparatus for thawing frozen sushi and a thawing device including the apparatus according to an embodiment of the present disclosure.

[0027] The thawing device 1 for frozen sushi in the present embodiment includes an apparatus 2 for thawing frozen sushi (hereinafter also referred to as the "thawing apparatus 2") and a steam, water vapor, or hot steam generating apparatus 3 (hereinafter, the "steam, water vapor, or hot steam generating apparatus 3" is also referred to as the "steam generating apparatus 3"). Here, the "apparatus" is a concept including not only dish-shaped or plate-shaped members but also container-shaped members.

[0028] In the present embodiment, the thawing apparatus 2 is disposed above the steam generating apparatus 3. However, the positional relationship between the thawing apparatus 2 and the steam generating apparatus 3 is not limited as long as the steam or the like generated from the steam generating apparatus 3 can pass through the hole 111 from the lower part to the upper part of the hole 111. For example, a configuration may be adopted in which the steam or the like generated from the steam generating apparatus 3 installed at an arbitrary location is guided to the lower part of the hole 111 by a pipe.

[0029] The thawing device 2 has a tray 11. Frozen sushi SS is placed on the tray 11. Specifically, it is possible to place the frozen sushi SS with the frozen rice on the bottom surface on the tray 11. As for the types of the frozen sushi SS, nigiri sushi, warship sushi (the one with nori wrapped on the outside; warship roll) are preferable, but not limited thereto. Also, the shape and size of the rice and the shape and size of the topping are not limited, but it is preferable that at least a part of the rice portion is in contact with the tray 11 when the frozen sushi SS is placed on the tray 11. Further, the frozen sushi SS is preferably one that has been rapidly frozen.

[0030] The tray 11 is provided with holes 111. Specifically, the holes 111 are provided at the locations on the tray 11 where the frozen sushi SS is placed. The holes 111 enable steam or the like generated from the steam or the like generating device 3 to pass from at least the lower part to the upper part of the holes 111. The steam or the like that has passed through the holes 111 from the lower part to the upper part hits the bottom surface of the frozen rice of the frozen sushi SS placed on the tray 11. That is, when thawing the frozen sushi SS, the thawing device 2 can direct steam or the like onto the bottom surface of the frozen rice of the frozen sushi SS from the holes 111 provided in the tray 11.

[0031] In addition, the periphery of the tray 11 is open to the outside air. More specifically, at least when thawing the frozen sushi SS, the periphery of the tray 11 is open to the outside air. Here, "the periphery of the tray 11 is open to the outside air" means that the heat of steam or the like, which is a heating source, is configured not to accumulate in the vicinity of the area on the tray 11 where the frozen sushi SS is placed. For example, "the periphery of the tray 11 is open to the outside air" may include that the steam or the like generated from the steam generating device 3 described later and passing through the holes 111 is configured not to stay in the area on the tray 11 where the frozen sushi SS is placed. However, even with the above description, a configuration in which steam or the like condensed (or dew-condensed) into water droplets adheres to the surface of the tray 11 is not excluded from the content of the present disclosure. As will be described later, the fact that the periphery of the tray 11 is open to the outside air has an advantage in preventing unfavorable phenomena such as "boiling" or "burning" of the sushi type.

[0032] On the other hand, as described above, as long as the heat of steam or the like is configured not to accumulate, other configurations, for example, a configuration having a lid formed on the upper part of the tray 11 may be adopted. Examples of other configurations include, for example, a configuration having a lid capable of heat exchange or heat recovery, a configuration having a lid made of a material that allows steam or the like to pass through but does not allow other substances (such as the frozen sushi SS and water 15 described later) to pass through, a configuration having a lid provided with a vent hole, and the like. In addition, regardless of the presence or absence of a lid or the presence or absence of openness to the outside air, a configuration in which the thawing device 1 or the thawing tool 2 is provided with a cooling system (which may be a mechanical heat exchange system or simply a system in which a coolant is placed) can also be adopted. In the example of FIG. 1, there is an advantage that large-scale equipment is not required, while in the example of providing a cooling system, there is an advantage that heat control can be facilitated.

[0033] Specifically, the tray 11 in the present embodiment has at least its upper surface open to the outside air. Since the steam or the like that has passed through the hole 111 is considered to move further upward of the tray 11, by opening the upper surface of the tray 11 to the outside air, it is possible to prevent the steam or the like from staying in the installation portion of the frozen sushi SS. Further, by opening at least a part of the side surface of the tray 11 to the outside air, it may be possible to prevent the steam or the like from staying in the installation portion of the frozen sushi SS. Further, it is preferable that the tray 11 is configured such that at least a part of the side surface of the rice of the frozen sushi SS is open to the outside air. By configuring in this way, it is possible to prevent the steam or the like from staying in the frozen sushi SS or in the surrounding space close to the frozen sushi SS.

[0034] The steam generating device 3 in the present embodiment includes an outer box 12 and a reaction vessel 14. Preferably, the steam generating device 3 (in one embodiment, the outer box 12 of the steam generating device 3) is connected to the thawing device 2 (in one embodiment, the tray 11 of the thawing device 2) and defines a sealed space between the tray 11 except for the hole 111. Note that the outer box 12 and the reaction vessel 14 may be integrally configured or may be individual members. For example, a configuration in which a part of the outer box 12 functions as the reaction vessel 14 can also be adopted.

[0035] Here, the "sealed space except for the hole 111" in the present disclosure refers to a space sealed to such an extent that most of the steam or the like generated in the steam generating device 3 can pass through the hole 111. In other words, the "sealed space except for the hole 111" in the present disclosure includes, but is not limited to, a space that does not allow any steam or the like to pass through except for the hole 111. By sealing the space with the steam generating device 3 and the thawing device 2, most of the thermal energy of the steam or the like can be used for thawing the frozen sushi.

[0036] Also, it is not necessarily required that the space between the steam generating device 3 (or the outer case 12 of the steam generating device 3) and the tray 11 be sealed. For example, (1) when the amount of steam or the like generated from the steam generating device 3 is sufficient, or (2) when the steam or the like generated from the steam generating device 3 has a directional flow toward the hole 111, it is not necessary to seal the space between the steam generating device 3 and the thawing device 2.

[0037] The reaction vessel 14 in the present embodiment is a vessel for reacting the heat generating material 13 with water 15. The heat generating material 13 generates heat by reacting with water 15 and gives thermal energy to water 15. The reaction vessel 14 is configured to be able to install the heat generating material 13 and pour water 15. The water 15 given thermal energy by the heat generating material 13 boils (vaporizes) into steam, moves upward from the reaction vessel 14, and passes through the hole 111. The steam (or the hot steam condensed from the steam) that has passed through the hole 111 hits the lower surface of the frozen rice of the frozen sushi SS and thaws the frozen sushi SS.

[0038] At least a part of the water 15 that has once vaporized into steam can become fine water droplet-like hot steam by condensing before reaching the frozen sushi SS. Also, when the calorific value of the heat generating material 13 is not so large, it is conceivable that the water 15 does not reach boiling and only hot steam instead of steam is generated from the reaction vessel 14. However, even hot steam can sufficiently hold the thermal energy for thawing the frozen sushi SS. Furthermore, it can be said that even hot steam can sufficiently pass through the hole 111. Therefore, in the present disclosure, what the steam generating device 3 generates or what passes through the hole 111 in the present disclosure may be not only steam but also hot steam.

[0039] Furthermore, when another potable liquid is used instead of water 15, what the steam generating device 3 generates may be steam instead of water vapor.

[0040] In this embodiment, when the thawing device 2 is arranged above the steam or other generating device 3, the reaction vessel 14 is configured to be located below at least a part of the hole 111. By positioning the reaction vessel 14 below the hole 111, steam or the like generated from the reaction vessel 14 will naturally flow towards the hole 111. Therefore, in this embodiment, it is easier to thaw the frozen sushi.

[0041] The steam or other generating device 3 is not limited to the configuration disclosed above. For example, as the steam or other generating device 3, a device that generates steam or the like by heating water using an electric heating wire, gas heating, or other means can also be adopted. One exemplary advantage when using the heating element 13 is that large-scale equipment is not required. On the other hand, exemplary advantages when adopting a device using an electric heating wire or the like include that there are no disposable members (or few disposable members), repeated use is easy, or a large number of frozen sushi can be thawed at once.

[0042] The heating element 13 and the water 15 may be sold separately from the frozen sushi thawing device 1, or may be prepared by the user of the frozen sushi thawing device 1. Also, the thawing device 2 and the steam or other generating device 3 may be sold separately. The thawing device 2 and the steam or other generating device 3 may both be disposable, or at least one of them may be reusable. Further, the frozen sushi SS may be sold separately from the frozen sushi thawing device 1, or may be sold as a food with utensils together with at least a part of the frozen sushi thawing device 1 (for example, the thawing device 2).

[0043] According to the frozen sushi SS thawing device 1 or the thawing device 2 of this embodiment described above, steam or the like passing through the hole 111 provided in the tray 11 will hit the lower surface of the rice of the frozen sushi SS. With such a configuration, the frozen sushi SS thawing device 1 or the thawing device 2 of this embodiment enables the thawing of the frozen sushi SS by steam or the like.

[0044] Since the steam or the like that has passed through the holes 111 is at a high temperature, the rice of the frozen sushi SS is rapidly and sufficiently heated. Therefore, the thawing device 1 or the thawing utensil 2 for the frozen sushi SS of the present embodiment can eliminate the whitening phenomenon of the frozen sushi SS.

[0045] Here, what the steam or the like that has passed through the holes 111 hits is the lower surface of the rice of the frozen sushi SS. However, in the present embodiment, not only the lower surface portion of the rice of the frozen sushi SS is thawed, but the entire frozen sushi SS is thawed. The reason why the entire frozen sushi SS is thawed despite applying steam or the like to the lower surface of the rice of the frozen sushi SS is considered to be as follows.

[0046] The rice portion of the frozen sushi SS is an aggregate of cooked and frozen rice grains, and there are sufficient gaps between the grains for steam or the like to pass through. Therefore, it is considered that the steam or the like that hits the lower surface of the frozen rice of the frozen sushi SS rapidly and sufficiently heats not only the lower surface of the rice but also the entire rice of the frozen sushi SS, and thaws the entire rice.

[0047] However, the above description does not prevent the coexistence of other heat transfer methods in addition to the content described above, such as heat conduction from already warmed rice grains to other rice grains.

[0048] Furthermore, the steam or the like that has reached the sushi ingredients of the frozen sushi SS through the gaps between the grains has transferred thermal energy to the already frozen rice. Therefore, it is considered that the steam or the like that has reached the sushi ingredients of the frozen sushi SS has lower thermal energy compared to the time when the steam or the like was generated. The steam or the like having relatively low thermal energy heats the sushi ingredients slowly and at a low temperature. By such slow and low-temperature heating, the prevention of boiling or burning of the sushi ingredients is realized.

[0049] Furthermore, in the present embodiment, when thawing the frozen sushi, the periphery of the tray 11 is open to the outside air. As a result, when thawing the frozen sushi, steam or the like does not stay around the tray 11, and the steam or the like is discharged to the outside air. Therefore, in the present embodiment, it is possible to prevent the remaining steam or the like having still high thermal energy from applying excessive heat to the sushi seed portion. Thereby, further prevention of overcooking or burning of the sushi seed is achieved.

[0050] As described above, the thawing device 1 or the thawing utensil 2 for the frozen sushi SS of the present embodiment realizes individual temperature control between the cooked rice and the sushi seed by applying steam or the like to the lower surface of the cooked rice of the frozen sushi SS from the holes 111 provided in the tray 11. Thereby, the thawing device 1 or the thawing utensil 2 for the frozen sushi SS of the present embodiment can eliminate the whitening of the cooked rice and prevent overcooking or burning of the sushi seed. Further, since the thawing device 1 or the thawing utensil 2 for the frozen sushi SS of the present embodiment thaws the frozen sushi SS using high-temperature steam or the like, it can thaw the frozen sushi SS relatively quickly, for example, in about 15 minutes, compared to the thawing method described in Patent Document 3.

[0051] In addition, when thawing the frozen sushi SS using the thawing device 1 or the thawing utensil 2 for the frozen sushi SS of the present embodiment, equipment such as a microwave oven is not required. Furthermore, the thawing device 1 or the thawing utensil 2 for the frozen sushi SS of the present embodiment does not need to thaw the cooked rice and the sushi seed individually, and there is no need to place the sushi seed on the cooked rice after thawing.

[0052] At present, as sushi is consumed worldwide, regardless of the eating place, the presence or absence of cooking facilities, or the presence or absence of the skill of the eater (or sushi provider) in making sushi, it is required to realize a technology for thawing frozen sushi with minimal effort and cost. In particular, when attempting to provide frozen sushi in an environment where open flames are prohibited and facilities are limited, such as on an airplane or a ship, regardless of the eating place, the presence or absence of cooking facilities, or the presence or absence of the skill of the eater (or sushi provider) in making sushi, it is strongly required to thaw the frozen sushi with minimal effort and cost. The thawing device 1 or thawing utensil 2 for the frozen sushi SS of the present embodiment provides a technology for thawing frozen sushi extremely simply with minimal effort and cost, regardless of the eating place, the presence or absence of cooking facilities, or the presence or absence of the skill of the eater (or sushi provider) in making sushi.

[0053] Furthermore, the thawing device 1 or thawing utensil 2 for the frozen sushi SS of the present embodiment thaws the frozen sushi SS using steam or the like. In other thawing methods, such as the method of placing frozen sushi on a hot plate, the drying of the frozen sushi progresses with heating, and the original taste, flavor, or texture of the sushi is lost. In the present embodiment, by using steam or the like, the humidity around the frozen sushi SS is maintained, so there is an advantage that drying of the frozen sushi during thawing can be prevented.

[0054] In addition to the above, as shown in FIGS. 3 and 4, the tray 11 may be provided with a guide 300 indicating the position where the frozen sushi SS should be installed. Since the position where the frozen sushi SS is installed is above the hole 111, the position of the guide 300 is around the hole 111.

[0055] The guide 300 is provided to indicate the position where the frozen sushi SS should be installed. The specific shape of the guide 300 may be designed in consideration of the thawing function and the handling property after thawing. Since the shape of the guide 300 is considered to affect the flow of steam or the like, in one example, the flow of steam or the like (and thus the thawing condition by steam or the like) may be considered when determining the shape of the guide 300. Also, depending on the shape of the guide 300, it may be considered that it becomes difficult for the diner to grasp the sushi with their hand or chopsticks. Therefore, in one example, the ease of grasping the sushi by the diner may be considered when determining the shape of the guide 300. However, the above description does not limit the shape of the guide 300 in any way.

[0056] FIG. 3 is a top view of the tray 11 in an example where the guide 300 is provided on a part of the tray 11. FIG. 4 is a cross-sectional view taken along line A-A in FIG. 3. However, in FIG. 4, for the sake of convenience of explanation, some expressions are simplified, and the dimensions of each member in FIG. 4 are not necessarily accurate. Also, in FIG. 4, the frozen sushi SS is illustrated by an imaginary line (note that the points to note regarding FIG. 4 also apply to FIGS. 5 and 6 described later).

[0057] The guide 300 may be formed, as in the examples of FIGS. 3 and 4, by a physical or mechanical structure, for example, by providing a convex portion on the tray 11. When the guide 300 is formed by providing a convex portion on the tray 11, it is preferable that the tray 11 including the guide 300 is configured such that at least a part of the side surface of the rice of the frozen sushi SS is open to the outside air. By configuring in this way, it is possible to prevent steam or the like from staying in the interior of the frozen sushi SS or in a space extremely close to the frozen sushi SS.

[0058] In addition to or instead of providing a convex portion on the tray 11, the guide 300 may guide the installation position by visually representing the installation position of the frozen sushi SS. For example, as the guide 300, a line representing the installation position of the frozen sushi may be adopted.

[0059] Further, the guide 300 may represent and guide the types of frozen sushi SS to be installed (for example, the types of sushi varieties). The types of frozen sushi SS to be installed may be represented, for example, by character information or by image information (such as photos or illustrations for each type of sushi variety). According to the guide 300 described above, when installing the frozen sushi SS on the tray 11, an appropriate type of frozen sushi SS can be installed, or the frozen sushi SS can be installed at an appropriate position.

[0060] The guide 300 may be provided only for some of the frozen sushi SS, as in the example of FIG. 3. In contrast, the guide 300 may be provided for all of the frozen sushi SS installed on the tray 11.

[0061] As yet another example, as shown in FIG. 5, the portion of the tray 11 where the frozen sushi SS is installed may be provided with uneven portions 500. The uneven portions 500 may be formed, for example, by embossing. Further, as shown in FIG. 6, a mesh portion 600 through which steam or the like can pass may be provided on the portion of the tray 11 where the frozen sushi SS is installed. The present disclosure also includes an example in which the tray 11 includes both the uneven portions 500 and the mesh portion 600.

[0062] The specific shape of the uneven portions 500 may be arbitrarily selected. In one example, the shape of the uneven portions 500 is an uneven repeating shape smaller than the size of the rice grains of the rice in the frozen sushi SS.

[0063] Also, the mesh size (mesh pitch), aperture ratio, wire diameter, thickness, and other parameters of the mesh portion 600 may be arbitrarily selected. In one example, the mesh portion 600 has a mesh smaller than the size of the rice grains of the rice in the frozen sushi SS. In another example, the aperture ratio of the mesh of the mesh portion 600 may be about 70% (73.7%). In yet another example, the mesh pitch may be about 1 mm. In yet another example, the thickness of the mesh may be about 0.5 mm.

[0064] By providing the uneven portion 500 or the mesh portion 600, the contact area between the tray 11 and the lower surface of the rice of the frozen sushi SS is reduced. In other words, by providing the uneven portion 500 or the mesh portion 600, a gap is formed between a part of the lower surface of the tray 11 and the lower surface of the rice of the frozen sushi SS. Thereby, it is possible to prevent the thawed rice from adhering to the tray 11, or it is considered that it becomes easier to apply steam or the like to the rice of the frozen sushi SS relatively uniformly.

[0065] The reason why the mesh portion 600 exhibits the above-described effects is considered to be that the frozen sushi SS (at least a part thereof) does not directly contact the tray 11 and that steam or the like (at least a part thereof) is not directly injected onto the frozen sushi SS. In view of the above, the "mesh portion" referred to in the present disclosure is not limited to a simple net-like member, but includes members that exhibit the above-described functions and effects, such as a sheet-like nonwoven fabric.

[0066] The uneven portion 500 or the mesh portion 600 may be provided over the entire upper surface of the tray 11 (the surface on which the frozen sushi SS is placed). On the other hand, the uneven portion 500 or the mesh portion 600 may be provided only on a part of the tray 11. Further, the uneven portion 500 or the mesh portion 600 is provided to prevent the rice of the frozen sushi SS from adhering to the tray 11 or to make it easier to apply steam or the like relatively uniformly to the rice of the frozen sushi SS. Therefore, in one example, the uneven portion 500 or the mesh portion 600 is provided around at least one hole 111.

[0067] Hereinafter, the thawing method of the frozen sushi according to the present embodiment will be further described. The thawing method of the frozen sushi according to the present embodiment includes a step of applying steam or the like from the hole 111 to the frozen sushi SS placed on the tray 11. Here, the frozen sushi SS is placed on the tray 11 with the frozen rice on the lower surface. Further, when thawing the frozen sushi SS, the periphery of the tray 11 is open to the outside air.

[0068] Further, the thawing method of the frozen sushi according to the present embodiment may include a step of placing the frozen sushi SS on the tray 11 with the frozen rice on the lower surface. The thawing method of the frozen sushi according to the present embodiment may include a step of generating steam or the like. The step of generating steam or the like may include, for example, a step of generating steam or the like using the steam or the like generating device 3. More specifically, the step of generating steam or the like may include a step of reacting the heating material 13 with water 15 inside a predetermined place, for example, the reaction vessel 14.

[0069] The thawing method of the frozen sushi according to the present embodiment may include a step of connecting the thawing device 2 and the steam or the like generating device 3. The step of connecting the thawing device 2 and the steam or the like generating device 3 may include a step of defining a sealed space between the thawing device 2 and the steam or the like generating device 3.

[0070] The thawing method of the frozen sushi according to the present embodiment described above can achieve individual temperature control between the rice and the sushi ingredients of the frozen sushi SS without requiring equipment such as a microwave oven, eliminate the white waxing of the rice, and prevent the boiling or baking of the sushi ingredients. In addition, the thawing method of the frozen sushi according to the present embodiment provides a technique for thawing frozen sushi with a minimum amount of labor and cost regardless of the eating place, the presence or absence of cooking equipment, or the presence or absence of the technique of making sushi by the eater (or the provider of sushi). Furthermore, the thawing method of the frozen sushi according to the present embodiment can prevent the drying of the frozen sushi during thawing.

[0071] Hereinafter, the details of this embodiment will be further described. For example, in FIG. 1, ten portions of frozen sushi SS are placed on a tray 11. In the example of FIG. 1, holes 111 are provided at the locations on the tray 11 where each portion of frozen sushi is placed. In the example of FIG. 1, the number of holes 111 for an individual portion of frozen sushi, that is, the number of holes 111 per portion of frozen sushi, is three. Here, the number of holes 111 for an individual portion of frozen sushi is not limited to three, and may be any number. However, from the viewpoint of uniformly heating the frozen sushi, preferably, the number of holes 111 for an individual portion of frozen sushi is two or more, and more preferably three or more. Also, in the example of FIG. 1, since the number of portions of frozen sushi SS is ten, in the tray 11, three holes 111 are formed in a set at each of the ten locations where each of the ten portions of frozen sushi SS is placed.

[0072] Also, the shape of an individual hole 111 may be, for example, circular. Further, the size of an individual hole 111 may be, for example, between a diameter of 2 mm and 5 mm. When there are a plurality of holes 111 used for one portion of frozen sushi, the longest distance among the distances between the holes may be, for example, between 16 mm and 22 mm.

[0073] The shape and size of the holes 111 and the distances between the holes, etc. (hereinafter referred to as "the shape, etc. of the holes 111") may be determined according to the size, type, freezing temperature, etc. of the frozen sushi SS (hereinafter referred to as "the size, etc. of the frozen sushi SS"). Since the temperature and amount of steam, etc. required for thawing the frozen sushi SS vary depending on the size, etc. of the frozen sushi SS, it is possible to adjust the temperature and amount of steam, etc. passing through the holes 111 by changing the shape, etc. of the holes 111. Also, the shape, etc. of the holes 111 may be determined according to the position of the holes 111 on the tray 11, the positional relationship between the holes 111 and the steam, etc. generating device 3 (more specifically, the source of steam, etc. (in the example of FIG. 1, the reaction vessel 14)), the temperature and amount of steam, etc. generated by the steam, etc. generating device 3, etc. (hereinafter referred to as "the position, etc. of the holes 111 on the tray 11"). Since the temperature and amount of steam, etc. passing through an individual hole 111 vary depending on the position, etc. of the holes 111 on the tray 11, it is possible to adjust the temperature and amount of steam, etc. passing through the holes 111 by changing the shape, etc. of the holes 111.

[0074] Figure 2 is a top view of the tray 11. The tray 11 in Figure 2 has dimensions of 225 mm × 225 mm on the outer periphery. Also, the material of the tray 11 is a heat-resistant material obtained by compounding talc with polypropylene. Furthermore, the tray 11 has an outer edge portion 112 and a sushi placement portion 113.

[0075] By the upper edge of the outer box 12 coming into contact with the lower surface of the outer edge portion 112 (the surface opposite to the surface (upper surface) shown in Figure 2), the thawing device 2 and the steam generating device 3 are connected, and the tray 11 is disposed above the opening of the outer box 12.

[0076] The sushi placement portion 113 is a flat portion formed in a state recessed from the outer edge portion 112 and has dimensions of 150 mm × 150 mm. In the sushi placement portion 113, the above-described holes 111 are formed at the locations (10 locations in this example) where the frozen sushi SS is placed.

[0077] The outer box 12 in Figure 1 is a paper box having outer dimensions of 195 mm × 195 mm × height 70 mm, and its upper part is open (an opening is formed). The tray 11 is connected onto the outer box 12 by a part of the lower surface of the outer edge portion 112 of the tray 11 coming into contact with the upper edge (the peripheral portion of the opening) of the outer box 12.

[0078] The heating material 13 in the present embodiment uses aluminum powder and calcium oxide powder as main raw materials, and when water 15 comes into contact, it adopts a material that causes a primary reaction of the following chemical formula (1) and a secondary reaction of chemical formula (2). CaO + H2O → Ca(OH)2 ··· (1) 2Al + 3Ca(OH)2 → 3CaO·Al2O3 + 3H2 ··· (2) Note that the heating material 13 is not particularly limited to the above-described one adopted in the present embodiment, and any material can be adopted as long as it undergoes an exothermic reaction when in contact with water 15 to generate high-temperature steam or the like.

[0079] In this embodiment, the reaction vessel 14 is composed of a heat-resistant tray with dimensions of 160 mm × 120 mm × 40 mm in height. However, the reaction vessel 14 is not particularly limited thereto, and any material can be adopted as long as it can withstand the heat generation of the heat-generating material 13 and has a material and size that prevent water 15 from leaking or spilling. Further, a reference line indicating an appropriate amount of water may be provided in the reaction vessel 14.

[0080] Figures 7A to 7I show the results of an experiment in which ten types of sushi were thawed under different conditions using the thawing device 1 shown in Figure 1. The conditions relate to the shape of the holes 111, the amount of the heat-generating agent, and the presence or absence of the mesh portion 600. Specifically, the state of the sushi after adding water that releases steam when reacting with water and waiting for 15 minutes is recorded.

[0081] As described above, one embodiment of the present disclosure has been described. However, the present disclosure is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope that can achieve the object of the present disclosure are included in the present disclosure. It should be noted that the advantages of the above-described embodiment are merely examples, and the scope of the present disclosure includes configurations that exhibit other advantages in addition to the above advantages, as well as configurations that exhibit only some of the above advantages.

Explanation of Reference Numerals

[0082] 1 ··· Thawing device for frozen sushi, 2 ··· Instrument for thawing frozen sushi (thawing instrument), 3 ··· Instrument for generating steam, water vapor, or hot steam (steam generating instrument), 11 ··· Tray, 12 ··· Outer box, 13 ··· Heat-generating material, 14 ··· Reaction vessel, 15 ··· Water, 111 ··· Hole, 112 ··· Outer edge portion, 113 ··· Sushi installation portion, 300 ··· Guide, 500 ··· Concavo-convex portion, 600 ··· Mesh portion, SS ··· Frozen sushi

Claims

1. An apparatus for thawing frozen nigiri sushi or gunkan-maki, comprising: a tray on which the nigiri sushi or the gunkan-maki can be placed; the tray is provided with a plurality of holes; the tray has uneven portions with a repeating shape of unevenness smaller than the size of rice grains in the area where the nigiri sushi or the gunkan-maki is placed; the apparatus is capable of thawing the nigiri sushi or the gunkan-maki by applying steam, water vapor or hot steam to the lower surface through the holes when the nigiri sushi or the gunkan-maki is placed on the tray with the rice on the lower surface.

2. The apparatus according to claim 1, wherein holes are provided in the area of the tray where the nigiri sushi or the gunkan-maki is placed.

3. An apparatus for thawing frozen nigiri sushi or gunkan-maki, comprising: a tray on which the nigiri sushi or the gunkan-maki can be placed; the tray is provided with a plurality of holes; the tray has a mesh portion in the area where the nigiri sushi or the gunkan-maki is placed, through which steam, water vapor or hot steam can pass; the apparatus is capable of thawing the nigiri sushi or the gunkan-maki by applying steam, water vapor or hot steam to the lower surface through the holes when the nigiri sushi or the gunkan-maki is placed on the tray with the rice on the lower surface.

4. The apparatus according to any one of claims 1 to 3, wherein the tray is provided with a guide indicating the position where the nigiri sushi or the gunkan-maki is placed.

5. The apparatus according to claim 1 or 2, wherein the tray is provided with a guide indicating the position where the nigiri sushi or the gunkan-maki is placed, and holes are provided inside the guide.

6. The apparatus according to any one of claims 1 to 3, and frozen nigiri sushi or gunkan-maki installed on the tray, An apparatus-equipped food product comprising the same.

7. An apparatus for thawing frozen nigiri sushi or gunkan-maki, comprising: a tray on which the nigiri sushi or the gunkan-maki can be placed; the tray is provided with a plurality of holes; the apparatus is capable of thawing the nigiri sushi or the gunkan-maki by applying steam, water vapor or hot steam to the lower surface through the holes when the nigiri sushi or the gunkan-maki is placed on the tray with the rice on the lower surface, and an apparatus for generating steam, water vapor or hot steam, A thawing device comprising the same.

8. The apparatus for generating steam, water vapor or hot steam is a reaction vessel for reacting a heating material with water to generate the steam, water vapor or hot steam The thawing device according to claim 7, comprising

9. A method for thawing frozen nigiri sushi or gunkanmaki, In an instrument having a tray on which the nigiri sushi or the gunkanmaki can be placed and provided with a plurality of holes in the tray, the nigiri sushi or the gunkanmaki is placed on the tray with the rice on the lower surface, and steam, water vapor or steam is generated by a steam, water vapor or steam generating device, and the steam, water vapor or steam is applied to the lower surface through the holes to thaw the nigiri sushi or the gunkanmaki.

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