JP2022070420A - Microwave aging method and microwave aging device - Google Patents

Abstract

To provide a microwave aging method and a microwave aging device which enable aging foods sufficiently while keeping them from excessive drying even in the case of drying and aging easy-to-dry foods and foods with low water contents by radiating microwave.MEANS FOR SOLVING THE PROBLEM: A microwave aging method has a dry aging process in which the surface of food M is dried and aged by radiating microwave on food M while blowing air in an aging chamber 40. In the dry aging process, the microwave radiating amount, the temperature in the aging chamber 40 and/or the air blowing amount are adjusted so that the internal temperature of the food M becomes higher than the surface temperature. And, at the same time, a breathable and moisture-permeable sheet S is put over the food M so that the water-evaporation is suppressed from the food M.SELECTED DRAWING: Figure 1

Description

The present invention relates to a microwave aging method and a microwave aging apparatus for aging food by irradiating it with microwaves.

In recent years, so-called aged meat, in which the umami taste of beef is increased by aging beef for a certain period of time, has become widely known, and the demand for it is increasing. When beef is aged, dry aging in which the beef is directly blown to a dry state and aging in a vacuum package is known, and wet aging in which the beef is aged in a vacuum package.
For example, the inventor discloses a technique for performing dry aging in a short aging period by irradiating the food stored in the aging chamber with microwaves while directly applying cold air (for example, Patent Document 1).

International Publication No. 2019/093365

In dry aging, the food can be aged while preventing the food from spoiling by blowing the wind on the food to dry the food and lowering the water content of the food. However, when the food to be aged is not a relatively large mass like meat, but a relatively small fillet like fish and shellfish and easy to dry, or when the water content is low like dried tea leaves. Has a problem that aging is difficult to proceed and a sufficiently aged food cannot be obtained. In particular, as in Patent Document 1, in the case of dry aging while irradiating with microwaves, the temperature inside the food can be raised by the microwaves, so that the water inside the food tends to evaporate easily, which is the above problem. Is particularly sought after.

INDUSTRIAL APPLICABILITY According to the present invention, even when a food that is easily dried or a food having a low water content is subjected to microwave irradiation for dry aging, it is possible to sufficiently ripen the food by suppressing excessive drying of the food. It is an object of the present invention to provide a microwave aging method and a microwave aging apparatus.

In order to achieve the above-mentioned problems, the present inventor has conducted extensive research to suppress the evaporation of water in foods even when dry aging of foods that are relatively easy to dry or foods that originally have a low water content. We have created a microwave aging method that can sufficiently ripen foods, and have completed the present invention.
That is, the present invention relates to the following microwave aging methods (1) to (6).
(1) A microwave aging method comprising a dry aging step of aging while drying the surface of the food by blowing air while irradiating the food housed in the aging chamber with microwaves, wherein the dry aging method is performed. In the process, in order to adjust the microwave irradiation amount, the temperature of the aging chamber, and / or the air volume so that the internal temperature is higher than the surface temperature of the food, and to suppress the water evaporation of the food. , A microwave aging method comprising covering the food with a breathable and breathable sheet.
(2) The microwave aging method according to (1) above, wherein the sheet has a notch, and the water evaporation amount of the food is adjusted by changing the size and / or the amount of the notch.
(3) A microwave aging method comprising a dry aging step of aging while drying the surface of the food by blowing air while irradiating the food housed in the aging chamber with microwaves, wherein the dry aging method is performed. In the process, in order to adjust the microwave irradiation amount, the temperature of the aging chamber, and / or the air volume so that the internal temperature is higher than the surface temperature of the food, and to suppress the water evaporation of the food. , (1) The air volume is less than 0.5 m / sec, and / or (2) the microwave irradiation amount so that the temperature difference between the surface temperature and the internal temperature of the food is within 8 ° C. A microwave aging method comprising controlling the temperature of the aging chamber and / or the air volume.
(4) The microwave aging method according to any one of (1) to (3) above, wherein the food is dried tea leaves, fish fillets, or fish eggs.
(5) The microwave aging method according to any one of (1) to (4) above, wherein the dry aging step further includes a step of spraying water on the surface of the food.
(6) In the dry aging step, when the internal temperature of the food can be directly measured in contact with the food, the irradiation amount of the microwave and the irradiation amount of the microwave in the aging chamber are based on the measured internal temperature of the food. If the temperature and / or the air volume is adjusted and the internal temperature of the food cannot be directly measured in contact with the food, the temperature of the water placed in the container housed in the aging chamber together with the food is measured. The microwave aging method according to any one of (1) to (5) above, wherein the irradiation amount of the microwave, the temperature of the aging chamber, and / or the air volume are controlled based on the measured temperature.

The present invention also relates to the microwave aging apparatus according to (7) below.
(7) A aging chamber for storing food, a microwave oscillating unit for oscillating microwaves irradiated in the aging chamber, a cooler for cooling the air in the aging chamber, and air cooled by the cooler. A fan that blows air into the aging chamber, a control unit that controls the microwave irradiation amount, the temperature of the aging chamber, and / or the air volume of the fan by the microwave oscillating unit, and a control unit that controls the air volume of the fan, and the food is operated by the user. It has an operation unit capable of selecting a dry aging mode for dry aging, and the control unit is for suppressing water evaporation of the food when the dry aging mode is selected by the operation unit. , (1) Make the air volume of the fan less than 0.5 m / sec, and / or (2) Irradiate the microwave so that the temperature difference between the surface temperature and the internal temperature of the food is within 8 ° C. A microwave aging device comprising controlling the amount, the temperature of the aging chamber, and / or the air volume.

According to the present invention, even when a food that is easily dried or a food having a low water content is irradiated with microwaves for dry aging, it is possible to suppress excessive drying of the food and sufficiently ripen the food. A microwave aging method and a microwave aging apparatus can be provided.

It is a block diagram of the microwave aging apparatus which concerns on this embodiment. It is a figure which shows the structure of the internal temperature sensor which concerns on this embodiment. It is a figure for demonstrating the dry aging method which concerns on this embodiment. It is a figure which shows the measurement result of the amino acid content in the dry aging test of the raw tea leaf. It is a figure which shows the result of the sensory evaluation in the dry aging test of Sujiko. It is a figure which shows the measurement result of the free amino acid in the dry aging test of red sea bream. It is a figure which shows the measurement result of the total free amino acid and the nucleic acid component in the dry aging test of red sea bream.

The microwave aging device 1 according to the present embodiment cools the surface of the food M to which microorganisms adhere by irradiating the food M with cold air while blowing cold air to suppress spoilage, and also suppresses spoilage of the food by the microwave. The internal temperature can be raised and aging can be promoted. In this embodiment, dry aging (dry aging) using such a microwave aging device 1 will be described. In particular, in the microwave aging method according to the present embodiment, in order to suppress excessive drying of food M in dry aging, (1) breathability and moisture permeability of cooking sheets and aging sheets used in wet aging. Dry aging is performed by covering the food M with the sheet S having the above, (2) the dry aging is performed with the air volume of the fan 43 being less than 0.5 m / sec, and (3) the temperature difference between the surface temperature and the internal temperature of the food M. We propose three methods of performing dry aging by controlling the microwave irradiation amount, the temperature of the aging chamber, and the air volume so that the temperature is within 8 ° C. By these methods, not only food M that is hard to dry like beef chunks but food M that is easy to dry with small fillets such as fish and shellfish and food M with low water content such as dried tea leaves can be used for dry aging. It is possible to suppress the evaporation of water in the food M and sufficiently mature the food M. It should be noted that the above three methods are methods aimed at sufficiently aging even foods that are easily dried or foods M having a low water content by dry aging, and any one method may be used or 2 The above methods may be combined. In the following, first, the microwave aging apparatus 1 according to the present embodiment will be described.

(Microwave aging device)
FIG. 1 is a configuration diagram of a microwave aging device 1 according to the present embodiment. The microwave aging device 1 according to the present embodiment is a device capable of dry aging and wet aging, and includes meat (including processed meat foods such as ham), seafood, dairy products such as cheese, and beans such as coffee beans. , Vegetables, fruits, noodles, breads, liquors such as wine, and various foods M such as fermented foods (including fermented seasonings such as miso and soy sauce) can be aged. However, as described above, the microwave aging method according to the present embodiment is particularly useful for dry aging of food M, which is easy to dry with small fillets such as fish and shellfish, and food M, which has a low water content such as dried tea leaves. ..

As shown in FIG. 1, the microwave aging device 1 includes a cooler 10, a refrigerant flow path 20, a microwave oscillating unit 30, an aging chamber 40, a heat insulating unit 50, an internal temperature sensor 60, a control unit 70, and a UV lamp 80. And an operation unit 90 is provided.

As shown in FIG. 1, the cooler 10 is connected to the refrigerant flow path 20 and cools the refrigerant circulating in the refrigerant flow path 20. As the cooler 10, for example, a known device having a compressor, a condenser, or the like and capable of cooling the refrigerant by heat exchange with the outside can be used.

The refrigerant flow path 20 is connected to the cooler 10, and the refrigerant for cooling the air in the internal space of the aging chamber 40 circulates. The refrigerant flow path 20 is in direct contact with the wall portion 41 of the aging chamber 40, and the refrigerant circulating in the refrigerant flow path 20 exchanges heat with the wall portion 41 of the aging chamber 40 to exchange heat with the wall portion 41 of the aging chamber 40. The portion 41 is cooled, and the air in the aging chamber 40 in contact with the wall portion 41 is cooled. Then, the refrigerant warmed by heat exchange returns to the cooler 10 again and is cooled by the cooler 10. The refrigerant is not particularly limited, and for example, HFC (hydrofluorocarbon), HC (hydrocarbon), or the like can be used.

The microwave oscillating unit 30 oscillates a microwave for irradiating the food M. In the present embodiment, a solid-state semiconductor oscillator using a semiconductor element is used as the microwave oscillator 30. Compared to magnetrons, semiconductor oscillators can obtain higher frequencies and output stability, and can precisely control output values and frequencies in units of several microseconds. The microwave oscillated by the microwave oscillating unit 30 is irradiated into the aging chamber 40 from the irradiation port 42 of the aging chamber 40 via the cable 31.

The food M for aging is placed in the aging room 40. The microwave oscillated by the microwave oscillating unit 30 is irradiated into the aging chamber 40 from the irradiation port 42 via the cable 31, and uniformly heats the food M placed in the aging chamber 40. In the present embodiment, a small patch antenna (planar antenna) having a high gain is attached to the irradiation port 42, whereby the microwave oscillated by the microwave oscillating unit 30 is irradiated into the aging chamber 40. To. Further, the refrigerant flow path 20 is in direct contact with the wall portion 41 of the aging chamber 40 without a gap, the refrigerant flowing through the refrigerant flow path 20 cools the wall portion 41 of the aging chamber 40, and the wall portion 41 is a wall. By cooling the air in the aging chamber 40 that comes into contact with the portion 41, the food M can be cooled from the surface. This makes it possible to raise the internal temperature of the food M to be higher than the surface temperature of the food M.

Further, as shown in FIG. 1, the aging chamber 40 includes a fan 43 and a door (not shown). The fan 43 can blow air at an air volume suitable for general aging of food M (for example, 0.5 to 10.0 m / sec). Further, in the present embodiment, the fan 43 can blow air at an air volume of less than 0.5 m / sec. By convection of the air in the aging chamber 40, the fan 43 can apply the cold air cooled by the refrigerant to the food M, whereby the surface of the food M can be efficiently cooled. In addition, the door has a choke structure to prevent microwaves from leaking to the outside, and can be opened and closed from the outside. The choke structure can be a known structure. The user can open and close the door to put the food M to be aged in and out of the aging room 40. Further, reflectors for reflecting microwaves are installed on all the inner surfaces (inner walls) of the wall portion 41 of the aging chamber 40. In the aging chamber 40, shelves of any shape made of a microwave permeable material such as Teflon (registered trademark) or polypropylene may be installed. When a metal material such as stainless steel is used, a grid-like shelf having an interval of 20 mm or more or a punching metal-shaped shelf having an opening having a diameter of 20 mm or more may be installed.

The heat insulating portion 50 is a member for suppressing heat exchange with the outside air before the refrigerant flowing through the refrigerant flow path 20 reaches the aging chamber 40. As shown in FIG. 1, the heat insulating portion 50 is in direct contact with the refrigerant flow path 20 without a gap, and sandwiches the refrigerant flow path 20 together with the wall portion 41 of the aging chamber 40. The material of the heat insulating portion 50 is not particularly limited, and for example, styrofoam or urethane can be used.

The internal temperature sensor 60 measures the internal temperature of the food M. Here, FIG. 2 is a diagram showing the configuration of the internal temperature sensor 60 according to the present embodiment. As shown in FIG. 2, the internal temperature sensor 60 has a sheath portion 61, a sleeve portion 62, a lead wire portion 63, and an internal connector 64. Further, as shown in FIG. 1, the internal temperature sensor 60 is connected to the receiver 68 outside the aging chamber 40 via the internal connector 64, the internal adapter 65, the external adapter 66, and the external connector 67. , The temperature is measured by the receiver 68.

Further, in the present embodiment, the microwave aging device 1 has an external temperature sensor (not shown) for measuring the surface temperature of the food M. As the external temperature sensor, for example, a radiation type temperature sensor that measures the intensity of infrared rays or visible light by non-contact can be used, and a configuration that does not have an external temperature sensor is also possible.

The internal temperature of the food M measured by the internal temperature sensor 60 and the surface temperature of the food M measured by the external temperature sensor are output to the control unit 70. Then, as will be described later, the control unit 70 controls the temperature and the air volume based on the internal temperature of the food M measured by the internal temperature sensor 60 and / or the external temperature of the food M measured by the external temperature sensor. Control is done.

The control unit 70 incorporates a program that controls the temperature so that the surface temperature and the internal temperature of the food M to be aged become predetermined temperatures, respectively. Specifically, the control unit 70 is a cooler 10 and a microwave oscillating unit based on the internal temperature of the food M measured by the internal temperature sensor 60 and / or the external temperature of the food M measured by the external temperature sensor. By controlling the operations of the 30 and the fan 43, the temperature of the cold air by the cooler 10, the output of the microwave by the microwave oscillating unit 30, and the air volume of the fan 43 are controlled to control the temperature. For example, the control unit 70 can raise the internal temperature of the food M by increasing the microwave output of the microwave oscillating unit 30, lowers the temperature of the cold air by the cooler 10, or lowers the temperature of the fan. By increasing the air volume of 43, the surface temperature and / or the internal temperature of the food M can be lowered.

Further, the control unit 70 can control the oscillation of microwaves by the microwave oscillation unit 30. In particular, in the present embodiment, the microwave oscillator 30 is a semiconductor oscillator, and the microwave oscillation can be controlled with high accuracy. Then, the control unit 70 irradiates the microwave by controlling the oscillation of the microwave by the microwave oscillation unit 30.

When the food M is aged by irradiating the food M with microwaves in this way, the microwave heats the inside of the food by dielectric heating, so that the inside of the food M can be heated in addition to the surface of the food M. Normally, warming the inside of food M can promote the aging of food M, but warming the surface of food M promotes the growth of bacteria adhering to the surface of food M. On the other hand, in the microwave aging apparatus 1 according to the present embodiment, the surface of the food M is cooled by the operation of the cooling mechanism, that is, the cooler 10 and the fan 43, so that the bacteria adhering to the surface of the food M are grown. Proliferation can be suppressed.

In particular, in the microwave aging device 1 according to the present embodiment, the food M is heated by the heating mechanism (microwave oscillating unit 30) and the food M by the cooling mechanism (cooler 10 and fan 43) under the control of the control unit 70. By simultaneously cooling the surface of the food M, the operation of the heating mechanism and the cooling mechanism is controlled so that the surface temperature of the food M becomes lower than the internal temperature. Specifically, the control unit 70 controls the temperature of the cold air by the cooler 10, the output of the microwave oscillation unit 30, and the air volume by the fan 43 so that the surface temperature of the food M is lower than the internal temperature. It is not necessary to continuously irradiate the food M with microwaves during the aging period, and the microwaves are irradiated for at least 1 hour (preferably 3 hours or more, more preferably 5 hours or more). It can be configured.

Further, in the present embodiment, the microwave aging device 1 is provided with an operation unit 90 for the user to operate, and the user operates the operation unit 90 to control the temperature suitable for dry aging of the food M and to control the temperature. The microwave aging device 1 can execute the dry aging mode for controlling the air volume. Further, in the microwave aging apparatus 1 according to the present embodiment, in addition to the normal dry aging mode in which a meat mass such as beef is dry-aged, such as food M having a small fillet such as fish and shellfish and easy to dry, and dried tea leaves. A specific dry aging mode for appropriately dry-aging food M having a low water content can be selected by the operation unit 90. When the specific dry aging mode is selected, food M and water that are easy to dry can be selected. It is also possible to perform temperature control and air volume control suitable for food M having a low content. The temperature control and air volume control in the normal dry aging mode and the specific dry aging mode will be described later.

The UV lamp 80 is a device that generates ultraviolet rays. In the present embodiment, by installing the UV lamp directly in the aging chamber 40, the surface of the food M placed in the aging chamber 40 is irradiated with the ultraviolet rays generated by the UV lamp 80 during the aging of the food M. can do. As described above, by directly irradiating the surface of the food M with ultraviolet rays during aging, the growth of bacteria existing on the surface of the food M can be further suppressed. The control unit 70 can also control the operation of the UV lamp 80. For example, the control unit 70 controls the UV lamp 80 to irradiate ultraviolet rays for a certain period of time (for example, several hours) from the timing when aging is started or the timing when the door of the aging chamber 40 is closed (after opening). be able to.

(Dry aging)
Next, the dry aging of the food M according to the present embodiment will be described. The dry aging is a method of aging the food M while suppressing spoilage by aging the food M while drying it by directly blowing wind on the food M without wrapping the food M in a vacuum pack or the like. In the normal dry aging mode in which a meat mass or the like is aged, the meat M is arranged so as to be directly exposed to the wind in order to suppress spoilage, and the air volume suitable for general aging (for example, 0.5 to 10.0 m). Aging is performed at (/ sec). Further, in the present embodiment, in the normal dry aging mode, the temperature of the cold air by the cooler 10 and the microwave by the microwave oscillating unit 30 are set so that the difference between the surface temperature and the internal temperature of the food M exceeds 8 ° C. By controlling the output of the food M and the air volume of the fan 43, the ripening of the inside of the food M is promoted while suppressing the growth of bacteria adhering to the surface of the food M.

On the other hand, when dry aging is performed in a normal dry aging mode for food M such as fish and shellfish, which has a small fillet and is easy to dry, or food M, which has a low water content such as dried tea leaves, the food M dries immediately. There was a problem that it was not possible to obtain a sufficient aging period. Therefore, in the present embodiment, for the food M that is easy to dry and the food M having a low water content, in order to suppress the water evaporation of the food M and obtain a sufficient aging period, the following (1) to (3) Dry aging is performed by the microwave aging method. The microwave aging method (1) below can be performed in both the normal dry aging mode and the specific dry aging mode described above, and the microwave aging methods (2) and (3) can be performed in the specific dry aging mode. It is done by mode.

(1) Method of Covering Food M with Sheet S and Performing Microwave Aging FIG. 3 is a diagram for explaining an example of the microwave aging method according to the present embodiment. In the present embodiment, as shown in FIG. 3, the food M is housed in a container C such as a colander or a bat, and the upper surface of the container C containing the food M is covered with a sheet S. By covering the food M with the sheet S in this way, it is possible to prevent the food M from being directly exposed to the cold air, so that the water vapor generated by the irradiation of the food M with the microwave can be diffused to the outside of the container C. It can be suppressed and the humidity inside the container C can be maintained in a high state, effectively preventing the water in the food M from excessively evaporating and drying the food M beyond the range suitable for aging. can do. Although the figure shown in FIG. 3 illustrates a configuration in which the sheet S is covered so as not to come into contact with the food M, the sheet S may be covered with the food M so as to be in contact with the food M and the sheet S. good. Further, as shown in FIG. 3, the configuration is not limited to covering only one side of the food M with the sheet S, and the entire food M may be wrapped with the sheet S.

Further, the sheet S is made of a material that is resistant to microwaves and has breathability and moisture permeability. When the sheet S has air permeability, the air cooled by the cooler 10 can pass through the sheet S to cool the surface of the food M, and when the sheet S has moisture permeability, the air from the food M can be cooled. It is possible to prevent the evaporated water vapor from condensing on the sheet S and dropping onto the food M. As such a sheet S, a commercially available cooking sheet or an aging sheet can be used. Further, tissue paper, kitchen paper and the like can also be used as long as they have the above characteristics. The sheet S is provided with a notch N, and the water evaporation of the food M can be adjusted according to the size of the notch N and / or the amount of the notch N. For example, in a food M such as dried tea leaves having a low water content, the water evaporation amount of the food M can be reduced by reducing the size of the cut N or reducing the amount of the cut N. Further, in the food M which may be gradually dried such as fish and shellfish, the water evaporation amount of the food M can be increased by making the cut N relatively large or by increasing the amount of the cut N relatively. can.

(2) Method of performing microwave aging with the air volume of the fan 43 set to less than 0.5 m / sec Further, the microwave aging device 1 according to the present embodiment is the moisture content of the food M when the specific dry aging mode is selected. By controlling the operation of the fan 43 by the control unit 70 in order to suppress evaporation and obtain a sufficient aging period, the air volume of the fan 43, which is 0.5 to 10.0 m / sec in the normal dry aging mode, is 0. It can be controlled to less than .5 m / sec. As a result, it is possible to prevent the food M from becoming too dry due to the cold air blown from the fan 43, and to promote the aging of the food M.

(3) A method of performing microwave aging with the difference between the external temperature and the internal temperature of the food M being within 8 ° C. Further, the microwave aging device 1 according to the present embodiment is used when the specific dry aging mode is selected. The control unit 70 adjusts the microwave irradiation amount, the temperature of the aging chamber 40, and the air volume of the fan 43 so that the difference between the surface temperature and the internal temperature of the food M is within 8 ° C. By setting the difference between the surface temperature and the internal temperature of the food M to be within 8 ° C., it is possible to suppress the drying of the food M and secure a sufficient aging period.

(4) Others For food M, which has a low water content from the beginning and is difficult to mature, such as dried tea leaves, before performing dry aging by the microwave aging methods described in (1) to (3) above, food M It is also possible to promote the aging of the food M by spraying water on the surface of the food M with a mist or the like to moisten the food M. Further, even in the case of food M such as fish and shellfish, which is easy to dry, it is possible to maintain the water content suitable for aging by spraying water on the food M by spraying or the like during the dry aging process. As described above, by spraying water on the food M by spraying or the like to maintain the water content suitable for aging, a sufficient aging period can be secured and the food M can be sufficiently aged. For example, in the case of dried tea leaves, the first spraying of water will dry them in about 4 days and the aging will not proceed, but by additionally spraying water during the dry aging, it will be possible to mature for 20 days. Instead of spraying water on the food M by spraying or the like, steam (not superheated steam) may be sprayed on the food M. Further, the microwave aging device 1 may be provided with a mechanism for automatically spraying water or steam on the food M.

Further, in the microwave aging apparatus 1 of the present embodiment, in the dry aging of meat lumps of beef or the like, the sheath portion 61 of the internal temperature sensor 60 is directly inserted into the food M to measure the internal temperature of the food M and measure the food. Temperature control and air volume control are performed based on the internal temperature of M. However, the food M to be aged may not be able to directly measure the internal temperature of the food M by inserting the sheath portion 61 of the internal temperature sensor 60, such as tea leaves and fish eggs. In the present embodiment, as shown in FIG. 3, for such a food M, water W is measured by putting water W in a container such as a beaker B and measuring the temperature of the water W with an internal temperature sensor 60. The temperature of the food M can be regarded as the internal temperature of the food M, and the temperature can be controlled and the air volume can be controlled. Further, in the configuration shown in FIG. 3, the food M may be aged by irradiating the food M with a microwave having a constant output without performing control based on the temperature measured by the internal temperature sensor 60. In this case, with the internal temperature sensor 60 inserted in the beaker B containing the water W, the beaker B is connected to the irradiation port 42 via the shelf 44 under the shelf 44 having a mesh having a predetermined pitch width (for example, within 2 cm). It is preferable to set it to stand still on the opposite side). As a result, the microwave emitted from the irradiation port 42 to the beaker B can be attenuated, the internal temperature sensor 60 can be protected, and the absorption of the microwave by the water W can be suppressed, which is sufficient for food M. It is possible to irradiate various microwaves.

Next, a test example of dry aging according to this embodiment will be described.

(Dry aging of dried tea leaves)
A dry aging test was conducted using commercially available dried tea leaves for black tea (summer picked dried tea leaves from Nepal) as a raw material. Specifically, 60 g of dried black tea leaves are spread on a polypropylene bat, 12 g of distilled water is sprayed on the bat, and then the upper surface of the bat is covered with a cooking sheet containing several cuts as shown in FIG. I set it in the aging room 40. Further, a beaker containing 50 ml of distilled water was allowed to stand in the aging chamber 40 for temperature control, and the temperature of the distilled water W in the beaker was measured by the internal temperature sensor 60. Then, the control unit 70 continuously irradiates microwaves for 9 days while cooling the room temperature to 0 ° C., so that the temperature of the distilled water W in the beaker becomes 5 ° C. The temperature and the microwave output by the microwave oscillating unit 30 were controlled. Further, during microwave irradiation, the fan 43 was blown at a maximum wind speed of 1 m / sec to circulate the air in the aging chamber 40. Then, the weight of the dried tea leaves was measured once a day, and dry aging was performed until the day when the weight did not change (9th day). As a comparative example, the same dried tea leaves were placed in a bag with a zipper and refrigerated at 0 ° C. for 9 days without irradiation with microwaves.

Dried black tea leaves aged for 9 days by the above dry aging method (Example 1) and dried black tea leaves aged for 9 days at a surface temperature and an internal temperature of 0 ° C. without irradiation with microwaves (comparison). For Example 1), a sensory test was conducted by two outside experts (food analysts). Specifically, for each dried tea leaf, hot black tea (1.5 g of tea leaves is extracted with 120 ml of hot water for 3 minutes) and iced black tea (4 g of tea leaves are extracted with 400 ml of water for about 6 hours) are brewed and tasted. Therefore, a sensory test was conducted.

As a result of the sensory test, it was evaluated that the difference between the dried tea leaves of Example 1 and the dried tea leaves of Comparative Example 1 is difficult to understand for hot black tea. On the other hand, regarding the iced black tea, it was evaluated that the black tea with dried tea leaves of Example 1 was clearly more delicious. In such an evaluation, in the iced black tea brewed with the dried tea leaves of Example 1, the ripening of the dried tea leaves was promoted and the components were changed, so that the astringency was improved (the astringency was in the mouth). It disappears quickly without any delay), and it is presumed that the original fruitiness and sweetness of honey are emphasized and made easier to understand because the dislike is no longer left.

(Dry aging of raw tea leaves)
Next, a dry aging test was conducted using raw tea leaves of Yame tea as a raw material. Specifically, 250 g of raw tea leaves were spread on a polypropylene colander and set in the aging room 40. Further, the beaker B containing 50 ml of distilled water was allowed to stand still in the aging chamber 40 for temperature control, and the distilled water W in the beaker B was measured by the internal temperature sensor 60. Then, the control unit 70 continuously irradiates the microwave for 13 days while cooling the temperature inside the refrigerator to 0 ° C., so that the temperature of the beaker B becomes 5 ° C., the temperature of the cold air and the microwave by the cooler 10. The microwave output by the oscillating unit 30 was controlled. Further, during microwave irradiation, the fan 43 was blown at a maximum wind speed of 1 m / sec to circulate the air in the aging chamber 40. Then, the weight of the raw tea leaves was measured once a day, and dry aging was performed until the day when the weight did not change (13th day). As a comparative example, 170 g of the same raw tea leaves were spread on a polypropylene colander and dried at 30 ° C. for 2 days without irradiation with microwaves.

The dried tea leaves (Example 2) in which the raw tea leaves of Yamecha were aged for 13 days by the above dry aging and the dried tea leaves in which the raw tea leaves of Yamecha were dried at 30 ° C. for 2 days without irradiation with microwaves (Example 2). The amino acid content was measured with respect to Comparative Example 2). FIG. 4 shows the measurement results of the amino acid content. In FIG. 4, the gray bar indicates the amino acid content of the dried tea leaves of Example 2, and the white bar indicates the amino acid content of the dried tea leaves of Comparative Example 2. The analysis was carried out by the Japan Food Research Laboratories, and free amino acids were measured by the automatic amino acid analysis method. As shown in FIG. 4, the total amino acid content of the dried tea leaves of Comparative Example 2 is high, whereas only glutamic acid and aspartic acid having two carboxyl groups in the molecule and the raw tea leaves of Example 2 are comparative examples. It was found that it increased with respect to the dried tea leaves of 2. From this, it was found that the umami component glutamic acid was selectively increased by aging the raw tea leaves at a low temperature as in Example 2.

Further, in the above dry aging test, dried tea leaves obtained by aging Yaotome's raw tea leaves for 13 days (Example 2) and dried tea leaves obtained by drying Yaotome's raw tea leaves at 30 ° C. for 2 days without irradiation with microwaves (Example 2). For Comparative Example 2), a sensory test was conducted by one outside expert (food analyst). Specifically, for each dried tea leaf, normal temperature (1 g of tea leaf is extracted with 100 ml of water for 3 hours), boiling water (1 g of tea leaf is extracted with 65 ml of boiling water for 1 minute), 70 ° C. (2nd roast, 1 g of tea leaf is extracted with 65 ml of boiling water). Each was extracted by 1 minute extraction), and the sensory test was performed by tasting the extracted tea. As a result, although the green odor remained in the aged or dried tea leaves, fruitiness was observed only in the tea leaves of Example 2 in the second decoction of the tea extracted at 70 ° C. Although the raw tea leaves could not be processed to the level of commercially available tea, it was confirmed that the microwave aging method according to the present embodiment reduced the astringency and increased the umami.

(Dry aging of Sujiko)
A dry aging test was conducted using commercially available Sujiko as a raw material. Specifically, about 800 g of Sujiko was placed in a polypropylene vat, the upper surface of the vat was covered with a cooking sheet having several cuts, and the vat was set in the aging chamber 40. In the aging chamber 40, a beaker B containing 50 ml of distilled water was allowed to stand still for temperature control, and while cooling the chamber temperature to -2 ° C, microwaves were continuously irradiated to adjust the internal temperature of the streak. Aging was carried out at 6 ° C. for 6 days. Further, during microwave irradiation, the fan 43 was blown at a maximum wind speed of 1 m / sec to circulate the air in the aging chamber 40. In addition, sampling was performed on the third day in the middle, and Sujiko aged for 3 days (Example 3) and Sujiko aged for 6 days (Example 4) were obtained. Then, the Sujiko of Examples 3 and 4 and the Sujiko (Comparative Example 3) that had been frozen and stored without being irradiated with microwaves were stored in a freezer (-30 ° C) and then transferred to a refrigerator (5 ° C) 24. After allowing to stand for a while and thawing, each sujiko was prepared into salmon roe by a chef at a Japanese restaurant using lukewarm water at about 40 ° C. and subjected to a sensory test.

The sensory test was conducted by a panel of 10 people with abundant eating experience at the Institute of Delicious Science. Further, in this sensory test, the salmon roe derived from Sujiko of Comparative Example 3 stored frozen without irradiation with microwaves was used as a control, and the “umami” and “specific to salmon roe” of the salmon roe derived from Sujiko of Examples 3 and 4. We compared and evaluated "taste intensity". In addition, each panel was asked to freely comment on each salmon roe.

FIG. 5 shows the salmon roe of Examples 3 and 4 which were aged for 3 days and 6 days after being irradiated with microwaves, using the evaluation of salmon roe derived from the salmon roe of Comparative Example 3 which was frozen and stored without being irradiated with microwaves as a control. It is a figure which shows the result of the sensory test of the "umami" of the origin salmon roe and "the intensity of the taste peculiar to salmon roe". Further, in FIG. 5, regarding "umami" and "taste intensity peculiar to salmon roe", the evaluation in Comparative Example 3 was set as 3 reference points, and 5 points when "strong" with respect to Comparative Example 3. The evaluation value of each panel is evaluated on a scale of 4 for "slightly strong", 3 for "same as Comparative Example 3," 2 for "slightly weak", and 1 for "weak". The average value was calculated. As shown in FIG. 5, regarding the salmon roe-derived salmon roe of Example 3 aged for 3 days by the dry aging according to the present embodiment, the “umami” and “taste intensity peculiar to salmon roe” are higher than those of Comparative Example 3. There were many people who felt strongly. In addition, as a comment on the salmon roe derived from Sujiko in Example 3 which was continuously irradiated with microwaves for 3 days, the impression that "the color and taste are the best and the range of utilization seems to be wide (the moist feeling is suitable for rice balls)" was obtained. Was done. The salmon roe-derived salmon roe of Example 4 that was aged for 6 days by irradiating with microwaves had an excessively long aging period, and the "umami" and "taste intensity peculiar to salmon roe" were higher than those of Comparative Example 3. Also declined.

(Dry aging of red sea bream)
A dry aging test was conducted using commercially available red sea bream (raw fish) as a raw material. Specifically, one red sea bream (raw fish) is cut into three pieces, one half of the body is stored frozen as it is, the other half (about 500 g of sea bream fillet) is put in the aging room 40, and a thermocouple is inserted. bottom. The temperature of the cold air by the cooler 10 and the output of the microwave by the microwave oscillator 30 were controlled so that the temperature in the aging chamber 40 was 0 ° C. and the internal temperature of the sea bream was 8 ° C. Further, during microwave irradiation, the fan 43 was blown at a maximum wind speed of 0.3 m / sec to circulate the air in the aging chamber 40. Then, the fillet of red sea bream was aged for 3 days by continuously irradiating with microwaves.

The contents of glutamic acid and free amino acids, and the contents of glutamic acid and free amino acids in the sea bream fillet aged for 3 days by the above dry aging (Example 5) and the sea bream fillet frozen and stored without irradiation with microwaves (Comparative Example 4). , Inosine and the content of the nucleic acid components of inosinic acid were measured. Glutamic acid is an amino acid related to umami, and inosinic acid is a nucleic acid component related to umami of fish, both of which are indicators of umami of fish. This analysis was carried out by the Institute of Meat Science and Technology, free amino acids were measured by automatic amino acid analysis, and inosinic acid was measured by high performance liquid chromatography. FIG. 6 and Table 1 below show the measurement results of free amino acids and the analysis results of nucleic acid components. In addition, FIG. 7 shows the measurement results of glutamic acid, total free amino acids, inosine, and inosinic acid.

As shown in FIG. 7, the content of glutamic acid and inosinic acid was increased in the bream fillet of Example 5 irradiated with microwaves as compared with the bream fillet of Comparative Example 4 not irradiated with microwaves. Specifically, in the microwave aging method (Example 5) according to the present embodiment, the content of glutamic acid is 63 after 3 days of dry aging as compared with the frozen storage without irradiation with microwaves (Comparative Example 4). %, And the content of inosinic acid increased by 7%. Also, in fish, glutamic acid generally increases as the aging period progresses, whereas inosinic acid tends to decrease, but by shortening the aging period with microwaves, glutamic acid can be obtained without decreasing inosinic acid. It was found that it is possible to provide aged fish containing a large amount.

In this test example, about 500 g of sea bream fillet was placed in the aging chamber 40 as it was for aging, but it is also effective to put the sea bream fillet in a bat and cover the sea bream fillet with an aging sheet for aging. Is. In this case, since the evaporation of water from the fillet of sea bream is suppressed, the optimum aging period is as long as 7 days, and the aging can be carried out for a longer period of time.

(Dry aging of southern bluefin tuna)
A dry aging test was conducted using southern bluefin tuna fillets as a raw material. Specifically, the fillet of southern bluefin tuna was put in a polypropylene vat, the upper surface of the vat was covered with a cooking sheet having several cuts, and the vat was set in the aging chamber 40. Further, while the room temperature was cooled to 0 ° C., microwaves were continuously irradiated to set the internal temperature of the southern bluefin tuna to 8 ° C., and the tuna was aged for 7 days. Further, during the microwave irradiation, the fan 43 was blown at a maximum wind speed of 1 m / sec to circulate the air in the aging chamber 40.

The contents of glutamic acid and inosinic acid in the fillet of southern bluefin tuna aged for 7 days by the above dry aging (Example 6) and the fillet of southern bluefin tuna stored frozen without irradiation with microwaves (Comparative Example 5). Was measured. As a result, it was found that glutamic acid increased 1.3 times and inosinic acid increased 1.1 times in the fillet of southern bluefin tuna of Example 6 as compared with the fillet of southern bluefin tuna of Comparative Example 5.

As described above, the microwave aging method according to the present embodiment is a dry aging step in which the surface of the food M is dried and aged by blowing air while irradiating the food M with microwaves (1). Covering the food M with the sheet S, (2) setting the air volume of the fan 43 to less than 0.5 m / sec, and (3) keeping the difference between the external temperature and the internal temperature of the food M within 8 ° C. By either method, the water evaporation of food M due to microwave irradiation can be suppressed, the water content of food M can be maintained in a range suitable for aging for a long time, and foods such as dried tea leaves having a low water content can be maintained. Even in the food M such as M and the food M such as fish and shellfish that are easily dried, a sufficient aging period can be obtained, and the food M can be sufficiently aged.

Further, in food M such as dried tea leaves, since the water content is low, aging does not easily proceed in dry aging. Can be promoted. Further, for foods such as tea leaves and fish eggs in which the internal temperature sensor 60 cannot be inserted into the food M to measure the internal temperature of the food M, water W is added to the beaker B housed in the aging chamber 40 as in the food M. By putting it in, measuring the temperature of water W in the beaker B with the internal temperature sensor 60, and estimating the measured temperature of water W as the internal temperature of food M, it is also appropriate for food M such as tea leaves and fish eggs. The temperature can be controlled and aging can be performed appropriately.

1 ... Microwave aging device 10 ... Cooler 20 ... Refrigerant flow path 30 ... Microwave oscillator 31 ... Cable 40 ... Aging chamber 41 ... Wall 42 ... Irradiation port 43 ... Fan 50 ... Insulation 60 ... Internal temperature sensor 70 ... Control unit 80 ... UV lamp 90 ... Operation unit

Claims (7)

A microwave aging method comprising a dry aging step of aging while drying the surface of the food by blowing air while irradiating the food housed in the aging chamber with microwaves.
In the dry aging step, the microwave irradiation amount, the temperature of the aging chamber, and / or the air volume are adjusted so that the internal temperature is higher than the surface temperature of the food, and the water evaporation of the food is performed. A microwave aging method comprising covering the food with a breathable and breathable sheet in order to suppress it. The sheet has a notch and
The microwave aging method according to claim 1, wherein the amount of water evaporation of the food is adjusted by changing the size and / or amount of the cut. A microwave aging method comprising a dry aging step of aging while drying the surface of the food by blowing air while irradiating the food housed in the aging chamber with microwaves.
In the dry aging step, the irradiation amount of the microwave, the temperature of the aging chamber, and / or the air volume are adjusted so that the internal temperature is higher than the surface temperature of the food.
In order to suppress the evaporation of water from the food
(1) The air volume is set to less than 0.5 m / sec, and / or
(2) The microwave irradiation amount, the temperature of the aging chamber, and / or the air volume are controlled so that the temperature difference between the surface temperature and the internal temperature of the food is within 8 ° C. , Microwave aging method. The microwave aging method according to any one of claims 1 to 3, wherein the food is dried tea leaves, fish fillets, or fish eggs. The microwave aging method according to any one of claims 1 to 4, further comprising a step of spraying water on the surface of the food in the dry aging step. In the dry aging step,
When the internal temperature of the food can be directly measured in contact with the food, the microwave irradiation amount, the temperature in the aging chamber, and / or the air volume are measured based on the measured internal temperature of the food. Adjust and
When it is not possible to directly measure the internal temperature of the food in contact with the food, the temperature of the water placed in the container housed in the aging chamber together with the food is measured, and the microwave of the microwave is measured based on the measured temperature. The microwave aging method according to any one of claims 1 to 5, wherein the irradiation amount, the temperature of the aging chamber, and / or the air volume are controlled. An aging room for storing food and
A microwave oscillating unit that oscillates microwaves irradiated in the aging chamber,
A cooler that cools the air in the aging chamber,
A fan that blows the air cooled by the cooler into the aging chamber,
A control unit that controls the microwave irradiation amount, the temperature of the aging chamber, and / or the air volume of the fan by the microwave oscillation unit.
It has an operation unit that is operated by the user and can select a dry aging mode for dry aging of food.
The control unit is used to suppress water evaporation of the food when the dry aging mode is selected by the operation unit.
(1) The air volume of the fan is set to less than 0.5 m / sec, and / or
(2) The microwave irradiation amount, the temperature of the aging chamber, and / or the air volume are controlled so that the temperature difference between the surface temperature and the internal temperature of the food is within 8 ° C. , Microwave aging device.

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