JP4581846B2 - Steaming device - Google Patents

Description

The present invention relates to cooking equipment for cooking the food using steam.

As disclosed in Patent Document 1 below, a mesh basket containing ingredients is stored in a steaming pot, and steam is supplied to the steaming pot to cook the ingredients (steamed). Steaming devices that can be used are known.
JP-A-9-266856

In the conventional steaming apparatus, the food is heated by continuously supplying steam into the steaming pot that is sealed and pressurized or depressurized. Therefore, it was not possible to stir the food during such a heating process. It is not preferable from the point of taste to cook by heating without stirring the ingredients. Problems which the present invention is to provide a simple structure to allow stirring of the ingredients during cooking, thereby to provide a cooking equipment that can cook taste excellent boiled and the like.

This invention was made in order to solve the said subject, The invention of Claim 1 is a processing tank in which the liquid foodstuff which consists of ingredients for boiled foods and a liquid is accommodated, In this processing tank Steam supply means for supplying steam to the steam, exhaust steam means for deriving air or steam from the treatment tank using a pressure difference from the atmospheric pressure, decompression means for reducing the pressure in the treatment tank, and in the treatment tank Control means for controlling the respective means based on the output of a pressure sensor for measuring the pressure of the pressure, steaming the food in the treatment tank at a pressure higher than the atmospheric pressure, and the treatment tank from the atmospheric pressure. Of the reduced-pressure steaming that steams the ingredients at low pressure, the selected steaming can be performed, and after the air is excluded from the processing tank, the steam is supplied into the processing tank by the steaming means, and the processing tank Inside the treatment tank while cooking the ingredients while keeping the inside at the desired pressure P1 The operation of returning to the desired pressure P1 after reducing the pressure to the set pressure P2 is performed once or a plurality of times, and the desired pressure P1 and the set pressure P2 can be changed, and the inside of the processing tank up to the set pressure P2 The depressurization of is performed using at least the exhausting means among the exhausting means and the decompressing means during the pressure steaming, while using the decompressing means during the steaming under reduced pressure. The return pressure to the desired pressure P1 is performed by supplying steam into the processing tank using the steaming means, and the set pressure P2 is a pressure at which a saturated steam temperature lower than the food material temperature is obtained, and The steaming apparatus is characterized in that the pressure is such that the temperature difference between the saturated steam temperature and the food material temperature after decompression is within a set range .

  According to the first aspect of the present invention, during the heating of the food by supplying steam into the processing tank, the pressure in the processing tank is temporarily lowered to boil the liquid content of the food, thereby Agitation can be achieved. Therefore, also in boiled food cooking, it can finish in the outstanding taste by stirring the soup. And since it is not necessarily stirred using a machine, a special apparatus is unnecessary.

According to the cooking equipment of the present invention, a simple configuration, to allow the agitation of the food during cooking, thereby it is possible to cook taste excellent boiled and the like.

Next, an embodiment of the present invention will be described.
Cooking equipment of the present invention is used in cooking of containing liquid material to at least a portion the liquid product ingredients (including food), in particular, as boiled such that boil the ingredients together with broth, solids It is suitably used for cooking a liquid food material consisting of a liquid component.

Cooking equipment of the present embodiment, in a state of accommodating the Ekibutsu foodstuff in the processing bath, and supplying steam to the process vessel, it is to heat the liquid product ingredients. At that time, the liquid food material may be heated (pressure steaming) while the inside of the processing tank is made higher than atmospheric pressure by the steam supplied into the processing tank, and conversely, the steam in the processing tank is sucked. The liquid food material may be heated (vacuum steamed) while discharging the outside or condensing the steam in the processing tank to make the inside of the processing tank at a pressure lower than the atmospheric pressure.

  During the heating process of the liquid food material by supplying steam into the processing tank, the liquid content in the liquid food material is boiled by temporarily lowering the pressure in the processing tank for a short time, thereby liquid food material Is agitated. This depressurization is performed by sucking and discharging the steam to the outside of the processing tank in a state where the supply of the steam to the processing tank is temporarily stopped, or condensing the steam in the processing tank instead of or in addition to that. . Moreover, in the case of pressure cooking, it can also carry out by guide | inducing vapor | steam outside a processing tank using differential pressure | voltage with atmospheric pressure.

  Temporary pressure reduction in the treatment tank for stirring the liquid food material is performed up to a pressure at which the liquid content of the liquid food material boils. Specifically, the liquid food material can be boiled by reducing the pressure in the treatment tank to a value equal to or lower than the saturated vapor pressure corresponding to the temperature of the liquid food material. That is, the inside of the treatment tank may be depressurized to a pressure at which a saturated steam temperature lower than the food material temperature is obtained.

  By the way, conventionally, liquid food materials such as boiled food are cooked under atmospheric pressure. When a liquid food material is heated in an open pan under atmospheric pressure, it will eventually boil. This is heated by a heat source having a temperature higher than 100 ° C., so that part or all of the food material is saturated with a saturated steam temperature ( This is because the temperature becomes 100 ° C.) or higher. However, when a food is heated in a saturated steam environment like a steaming device, heat is transferred to the food having a temperature lower than the steam temperature by condensation of surrounding steam. Therefore, normally, the foodstuff in a steaming apparatus always becomes below a saturated steam temperature, and does not boil. However, in the steaming apparatus of the present invention, during the steaming, the processing tank is depressurized temporarily to cause boiling in the liquid food material, thereby stirring the liquid food material.

  It is set as appropriate as to how much time or how much pressure or temperature is temporarily reduced in the processing tank for stirring the liquid food material. At this time, it is essential to reduce the pressure to a pressure or temperature that causes the liquid food material to boil. In addition, when the temperature difference between the saturated steam temperature and the food material temperature after decompression is large, the temperature difference is set so that it does not become too large because there is a risk of violent boiling and spilling. As the holding time under reduced pressure, it is not necessary to hold such a time that the food material temperature falls to the saturated steam temperature after the pressure reduction and does not boil.

  Temporary pressure reduction in the processing tank for stirring the liquid food material is performed one or more times during heating of the liquid food material by supplying steam into the processing tank. After such steaming, the inside of the treatment tank is restored to atmospheric pressure. However, the inside of the processing tank may be decompressed to vacuum-cool the liquid food material, and then the inside of the processing tank may be returned to atmospheric pressure.

  The steaming apparatus of the present embodiment is configured such that a processing tank is provided with steaming means, steaming means, decompression means, decompression means, control means, and the like.

  The treatment tank is a container that contains a liquid food material and can be sealed if necessary. The processing tank contains a container containing a liquid food material to be cooked. This container is typically a container that is opened only upward, and a top is covered with a sheet of moisture-permeable waterproof material that has the property of allowing steam to pass but not allowing water to pass through. You may do. Such accommodation of the container in the treatment tank may be directly placed on a shelf provided in the treatment tank or may be performed via a wagon that can be taken in and out of the treatment tank. In either case, the shelf on which the containers are placed may be meshed so that the vapor spreads all around the containers.

  The steam supply means is means for supplying steam from the boiler into the treatment tank. At this time, in consideration of hygiene, steam from a general boiler (primary boiler) is converted into steam from pure water or soft water in another boiler (secondary boiler). It is preferable to supply the clean steam into the treatment tank.

  The steaming means is a means for deriving the air and steam of the processing tank from the inside of the processing tank to the outside. Typically, it comprises a steaming line composed of piping that communicates the inside and outside of the treatment tank, and a steaming valve that is provided in the middle of this steaming line and adjusts the presence or absence of the communication. Therefore, particularly in a state where the inside of the treatment tank is pressurized by the steam supply by the steam supply means, the discharge of the steam to the outside of the treatment tank by the exhaust steam means can be performed by simply opening the exhaust steam valve and the pressure inside the treatment tank. It can be performed naturally using the pressure difference from the atmospheric pressure.

  The decompression means is means for decompressing the inside of the processing tank by sucking and exhausting air or steam in the processing tank to the outside or condensing the steam in the processing tank. The decompression means typically includes a vacuum pump and / or an ejector that decompresses the inside of the processing tank. Moreover, when using a vacuum pump, by providing a heat exchanger in front of the vacuum pump, it is possible to condense the vapor and increase the pressure reduction capability. The decompression means is preferably one that can adjust its decompression capability.

  The return pressure means is means for returning the pressure in the treatment tank decompressed by the pressure reduction means. Specifically, the outside air can be introduced into the decompressed treatment tank and the pressure inside the treatment tank can be restored to atmospheric pressure. It is desirable to introduce outside air into the treatment tank through a filter in consideration of hygiene.

  The control means is means for controlling the steam supply means, the steaming means, the pressure reducing means, and the pressure-reducing means to heat the liquid food material in the processing tank, and then vacuum-cooling it as desired. For cooking a liquid food material, typically, after a preheating and air exclusion process, a steaming process (heating process) is performed. These controls are performed using a pressure sensor that measures the pressure in the treatment tank. However, since the pressure in the treatment tank has a predetermined relationship with the temperature, it is possible to use a temperature sensor instead of the pressure sensor. In the present embodiment, control is also performed using a temperature sensor that measures the temperature of the liquid food contained in the processing tank. Furthermore, it is also possible to adjust the time for operating each of the means to adjust the inside of the processing tank to a desired pressure or temperature.

  The preheating and air exclusion step is a step of supplying steam into the processing tank by the steam supply means, discharging the air in the processing tank to the outside of the processing tank through the steaming means, and preheating the liquid food material. Further, the steam supply by the steam supply means after the decompression by the decompression means and the air removal by the steaming means after the steam supply by the steam supply means may be performed as many times as desired.

  The steaming step is a step of heating the food by supplying steam into the processing tank from which air has been removed by steaming means. At this time, as described above, the liquid food material may be steamed under pressure while the inside of the processing tank is set to a pressure higher than the atmospheric pressure by the steam supplied into the processing tank. The liquid food material may be steamed under reduced pressure while the pressure is lower than atmospheric pressure. And in this invention, the stirring process of a liquid foodstuff is performed 1 or more times during this cooking process.

In this stirring process, the supply of steam into the processing tank is temporarily stopped, the pressure in the processing tank is reduced for a short time, and the liquid content in the liquid food is boiled, thereby stirring the liquid food. Is to do. In the case of reduced-pressure steaming, a short-time pressure reduction can be performed by evacuating the steam in the treatment tank to the outside by the pressure reducing means. Further, in the case of pressure steaming, the pressure in the treatment tank can be released by releasing the pressure in the treatment tank, and the pressure reduction by the pressure reduction means may be used together if desired. After stirring treatment performs steam supply again to the processing bath, steaming is made of a liquid product ingredients.

  After the completion of the steaming process involving such a stirring process, the inside of the treatment tank is restored to atmospheric pressure, and a series of processes is completed. However, if desired, a vacuum cooling process may be performed in which the inside of the treatment tank is held under reduced pressure by a decompression unit to cool the liquid food material.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic structural diagram showing an embodiment of the steaming apparatus of the present invention. As shown in this figure, the steaming apparatus of the present embodiment includes a processing tank 3 for storing a liquid food material 2 placed in a container 1 opened only upward, and steaming means for supplying steam into the processing tank 3. 4, a steaming means 5 for deriving air and steam from the inside of the treatment tank 3, a decompression means 6 for evacuating and decompressing the inside of the treatment tank 3, and introducing outside air into the treatment tank 3 under reduced pressure The pressure recovery means 7 for returning pressure, the pressure sensor 8 for measuring the pressure in the processing tank 3, and the temperature sensor 9 for measuring the temperature of the food in the processing tank 3 are provided as main parts. The temperature sensor 9 may detect the food temperature without contact, but in the illustrated example, the temperature sensor 9 is inserted into the liquid food 2 to detect the food temperature.

  The processing tank 3 of the present embodiment is provided with a door 11 in a hollow box-shaped processing tank main body 10 so that it can be opened and closed, and has a pressure resistant structure. The door may be any of 11, a hinged door, a sliding door, or a shutter type movable in the vertical direction. By the way, the liquid food material 2 put in the container 1 is put into and out of the treatment tank 3 through the wagon 12 in this embodiment. The wagon 12 has casters 13, 13... At the bottom.

  The steam supply means 4 is means for supplying (steaming) steam into the treatment tank 3. The steam supply means 4 of the present embodiment includes a primary boiler (not shown) and a secondary boiler (reboiler) 14. Using the steam from the primary boiler as a heat source, the soft water is changed to steam by the secondary boiler 14. The clean steam thus generated is supplied into the treatment tank 3.

  Specifically, the secondary boiler 14 is a stainless steel heat exchanger 15 that heats soft water from the water supply pipe 16 and converts it into steam. In order to heat the soft water, steam from the primary boiler is supplied to the secondary boiler 14 via the steam supply pipe 17. Thus, the steam supplied from the primary boiler heats the soft water supplied into the stainless steel pipe of the secondary boiler 14. Thereby, clean steam is generated by the soft water in the secondary boiler 14.

  The clean steam generated in the secondary boiler 14 is supplied into the processing tank 3 via a steam supply line 18 as a steam supply pipe. In the middle of the steam supply line 18, a treatment tank steam supply valve 19 is provided. The processing tank steam supply valve 19 is configured to be capable of adjusting the presence / absence of steaming into the processing tank 3 and the amount of steam when steaming, and is typically composed of a proportional control valve. By adjusting the processing tank steam supply valve 19, the pressure in the processing tank 3 and thus the temperature can be adjusted. However, the pressure adjustment in the processing tank 3 can be performed by controlling not only the processing tank steam supply valve 19 but also the decompression means 6.

  The steaming means 5 is a means for deriving air or steam from the processing tank 3 to the outside. Specifically, it consists of a steaming line 20 as a steam discharge pipe, and air and steam in the processing tank 3 are led out of the processing tank 3 through this steaming line 20. In this embodiment, steam or the like can be discharged from the upper part of the processing tank 3 via the first exhaust valve 21 and the check valve 22, while the second exhaust valve 23 is also connected from the lower part of the processing tank 3. It can be discharged through. Each of these exhaust steam valves 21 and 23 is preferably composed of a valve whose opening degree can be adjusted, such as a proportional control valve, and the degree of communication inside and outside the treatment tank 3 is adjusted by adjusting the opening degree.

  In this embodiment, the decompression means 6 is configured by combining a steam ejector 24, a heat exchanger 25, and a vacuum pump 26. In this case, the steam ejector 24 has a suction port 27 connected to the processing tank 3, and a vacuum pump 26 is connected to the outlet 28 of the steam ejector 24 via a heat exchanger 25 and a check valve 29. . Therefore, by operating the vacuum pump 26 and injecting steam from the inlet 30 to the outlet 28 of the steam ejector 24, the air in the processing tank 3 to which the suction port 27 is connected is sucked and discharged. The inside can be depressurized. At this time, by providing the heat exchanger 25 in front of the vacuum pump 26, the steam can be cooled and condensed, and efficient decompression can be performed.

  In order to achieve this, the steam from the secondary boiler 14 can be supplied to the inlet 30 of the steam ejector 24 via the ejector steam supply valve 31. That is, in the present embodiment, the steam from the secondary boiler 14 is used for both steam supply to the inlet 30 of the steam ejector 24 and steam supply to the treatment tank 3. This switching can be performed by opening and closing the ejector steam supply valve 31 and the processing tank steam supply valve 19. However, only the primary boiler (not shown) can be used to supply the steam of the boiler to the ejector 24 and the processing tank 3. Further, clean steam from the secondary boiler 14 may be supplied to the treatment tank 3, and steam from the primary boiler may be supplied to the ejector 24.

  Further, as described above, the water-sealed vacuum pump 26 is connected to the outlet 28 of the steam ejector 24 via the heat exchanger 25 and the check valve 29. Water is supplied to the vacuum pump 26 through a sealed water supply valve 32, and the waste water from the vacuum pump 26 is discharged to a drain port (not shown). In addition, cooling water is also supplied to the heat exchanger 25 through the heat exchange water supply valve 33 and drained to the drain outlet. A sealed water supply valve 32 for supplying water to the vacuum pump 26 is opened in conjunction with the vacuum pump 26.

  By the way, it is preferable that the decompression means can adjust its decompression capability. For that purpose, the opening degree of the ejector steam supply valve 31 may be adjusted to control the capability of the steam ejector 24. Or you may control the rotation speed of the vacuum pump 26 using an inverter. Moreover, the opening degree of the heat exchange water supply valve 33 may be adjusted to adjust the amount of water supplied to the heat exchanger 25, or the water supply temperature thereof may be adjusted.

  The return pressure means 7 is a means for introducing outside air into the processing tank 3 so that the vacuum state in the processing tank 3 can be released. In this embodiment, the processing tank 3 can communicate with the outside air via the outside air introduction valve 34 and the filter 35. Therefore, when the outside air introduction valve 34 is opened, the inside of the processing tank 3 is opened to the atmospheric pressure, and outside air can be introduced into the processing tank 3 through the filter 35 and the inside of the processing tank 3 can be restored. Depending on how the outside air introduction valve 34 is opened, the pressure in the processing tank 3 can be gradually increased.

  Further, the steaming device is provided with a control means 36 for controlling the steam supply means 4, the exhaust steam means 5, the decompression means 6, the decompression means 7, and the like. The control means 36 controls the means 4 to 7 based on a detection signal from the pressure sensor 8 for detecting the pressure in the processing tank and the temperature sensor 9 for detecting the food temperature, in addition to the time to be grasped. It is a controller to control. Specifically, the treatment tank steam supply valve 19, the exhaust steam valves 21 and 23, the vacuum pump 26, the ejector steam supply valve 31, the sealed water supply valve 32, the heat exchange water supply valve 33, the outside air introduction valve 34, and the pressure sensor 8. The temperature sensor 9 is connected to the controller 36. And this controller 36 steams the liquid foodstuff 2 in the processing tank 3 so that it may mention later based on a predetermined | prescribed procedure (program).

  FIG. 2 is a diagram illustrating an example of a pressure change in the treatment tank 3 during the operation of the steaming apparatus according to the present embodiment. The steaming apparatus of a present Example is used suitably for heat cooking, such as simmered goods which consist of ingredients and soup. Specifically, in the metal container 1 opened upward, after putting together the solid content to be ingredients and the liquid content to be boiled juice, the container 1 is accommodated in the treatment tank 3, Cook boiled food. For this purpose, a steaming step is usually performed after the preheating and air exclusion step.

  In the preheating and air exclusion process, only the exhaust steam valves 21 and 23 are opened, the processing tank steam supply valve 19 is also opened, steam is supplied into the processing tank 3, and the processing tank steaming is performed after a predetermined time has elapsed. The valve 19 is closed, and the air in the processing tank 3 is discharged out of the processing tank 3 via the exhaust line 20. At this time, the inside of the treatment tank 3 may be decompressed by the decompression means 6 in advance, and then the steam may be supplied by the steam supply means 4 into the treatment tank 3 under the decompression.

  The steaming process of the present embodiment involves supplying steam into the processing tank 3 by the steam supply means 4 and pressurizing the processing tank 3 thereby. In other words, steam is supplied into the processing tank 3 so that the inside of the processing tank 3 has a pressure higher than the atmospheric pressure, and the liquid food material 2 is steamed under pressure. Specifically, with the ejector steam supply valve 31, the outside air introduction valve 34, and the exhaust steam valves 21 and 23 being closed, the processing tank steaming valve 19 is opened to supply steam into the processing tank 3. At this time, as described above, the steam supplied into the treatment tank 3 is clean steam generated from soft water in the secondary boiler 14. Therefore, safe and reliable cooking can be realized. Moreover, uniform cooking is performed in a short time by spreading clean steam around the entire periphery of the container 1.

  In the steaming step, the pressure in the processing tank 3 and the temperature are adjusted by adjusting the opening of the processing tank supply valve 19 and adjusting the amount of steam supplied into the processing tank 3. Specifically, the controller 36 adjusts the opening degree of the treatment tank steam supply valve 19 based on the output of the pressure sensor 8. By adjusting the pressure in the processing tank 3 in this way, the saturated steam temperature in the processing tank 3 is adjusted. In this embodiment, as shown in FIG. 2, after the pressure in the processing tank 3 is increased to the desired pressure P1, the pressure is maintained at the desired pressure P1 for a desired time.

  In the present embodiment, the liquid food material 2 is steamed under pressure by making the desired pressure P1 higher than the atmospheric pressure, but the liquid food material 2 may be steamed under reduced pressure by setting it lower than the atmospheric pressure. it can. In this case, steam may be supplied into the treatment tank 3 by the steam supply means 4 while the decompression means 6 is operated to decompress the inside of the treatment tank 3.

  During the steaming process, as shown in FIG. 2, at least one stirring process is performed in which the liquid food material 2 is stirred by temporarily reducing the pressure in the processing tank 3 to the set pressure P <b> 2 and boiling the liquid food material 2. Times are done. During the stirring process, the treatment tank steam supply valve 19 is temporarily closed, and the supply of steam into the treatment tank 3 is temporarily stopped. In this state, the inside of the processing tank 3 is reduced to a set pressure for a short time. The decompression during the pressure cooking may be performed by opening the exhaust steam valves 21 and 23 to release the pressure in the treatment tank 3. Moreover, what is necessary is just to depressurize the inside of the processing tank 3 by operating the pressure-reduction means 6 during vacuum cooking. Specifically, the vacuum pump 26 may be operated with the ejector feed valve 31, the sealed water feed valve 32, and the heat exchange feed valve 33 open.

  The pressure in the treatment tank 3 for the stirring treatment is reduced to a pressure at which a saturated steam temperature lower than the food material temperature is obtained. Therefore, in this embodiment, first, the food temperature is detected by the temperature sensor 9, and the pressure is reduced to below the saturated vapor pressure corresponding to the food temperature. Thereby, the liquid part (boiled juice) of the liquid foodstuff 2 in the processing tank 3 can be boiled, and, thereby, the liquid foodstuff 2 whole can be stirred. For example, the pressure is reduced to a pressure corresponding to 100 ° C. during cooking at 120 ° C., but it goes without saying that these temperatures can be changed as appropriate.

  Thus, according to the present Example, the foodstuff 2 in cooking can be stirred, without using a special apparatus like a stirring apparatus. By the way, air may be introduced from the outside into the container 1 in which the liquid food material 2 is placed to stir. In this case, the introduction of air into the container 1 may be forcibly blown using a pump or the like, but when the inside of the processing tank 3 is under reduced pressure, based on the pressure difference between the inside and outside of the processing tank 3, It is possible to send air naturally.

  In this case, an air introduction line (not shown) composed of a pipe line provided with an on-off valve (not shown) in the middle may be provided so as to communicate between the inside and outside of the treatment tank 3. One end of the air introduction line is opened under atmospheric pressure via a filter (not shown), and the other end is opened in the container 1. Thereby, air through the filter is introduced into the container 1 due to the pressure difference between the inside and outside of the processing tank 3 by opening the on-off valve under the reduced pressure in the processing tank 3 by the pressure reducing means 6. The introduction of air into the container 1 through the air introduction line is preferably performed from the bottom of the container 1. Thereby, the liquid foodstuff 2 can be stirred because the bubble rises in the liquid foodstuff 2. However, in consideration of heat transfer failure when air is introduced, it is desirable to stir only by reducing the pressure in the treatment tank 3 without introducing air.

  After the completion of the steaming process involving such a stirring process, the processing tank steam supply valve 19 is closed, the pressure in the processing tank 3 is restored to atmospheric pressure, and all the processes are completed. In the case of pressure steaming, this return pressure can be achieved by opening the exhaust steam valves 21 and 23, and in the case of vacuum steaming, the outside air introduction valve 34 can be opened.

Cooking equipment of the present invention may be appropriately modified without limited to the configuration of the embodiment. For example, in the case of pressure steaming, the stirring process during the steaming process uses not only the pressure release in the processing tank 3 by the steaming means 5 but also the pressure reduction in the processing tank 3 by the pressure reducing means 6 if desired. be able to. Moreover, it is possible to prevent spillage by slowing down the pressure reduction rate in the treatment tank 3.

It is a schematic structure figure showing one example of the steaming device of the present invention. It is a figure which shows an example of the pressure change in a processing tank in the driving | operation of the cooking apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Liquid food material 3 Processing tank 4 Steaming means 5 Dehumidifying means 6 Depressurizing means 7 Restoring means 8 Pressure sensor 9 Temperature sensor 36 Control means (controller)

Claims (1)

A processing tank in which liquid ingredients composed of ingredients for boiled food and liquid are stored ;
Steam supply means for supplying steam into the treatment tank;
A steaming means for deriving air or steam from the inside of the treatment tank using a pressure difference from the atmospheric pressure;
Decompression means for decompressing the inside of the treatment tank;
Control means for controlling each means based on the output of a pressure sensor for measuring the pressure in the treatment tank,
Among the pressure steaming that steams the ingredients with the inside of the treatment tank at a pressure higher than the atmospheric pressure and the vacuum steaming that steams the ingredients with the pressure inside the treatment tank at a pressure lower than the atmospheric pressure, the selected steaming can be performed,
After the air is removed from the inside of the processing tank, steam is supplied into the processing tank by the steam supply means, and the inside of the processing tank is kept at the desired pressure P1 while cooking the food. Performing the operation of returning to the desired pressure P1 after depressurization until one or more times,
The desired pressure P1 and the set pressure P2 can be changed,
The pressure in the treatment tank up to the set pressure P2 is such that at least the steaming means is used among the steaming means and the pressure reducing means during the pressure steaming, while the pressure reducing means is used during the steaming under reduced pressure. Using
The return pressure from the set pressure P2 to the desired pressure P1 is performed by supplying steam into the processing tank using the steaming means,
The set pressure P2 is a pressure at which a saturated steam temperature lower than the food material temperature is obtained, and is a pressure in which the temperature difference between the decompressed saturated steam temperature and the food material temperature is within a set range. apparatus.

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