JP2006212037A - Method for heating food and food heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for heating a food causing little breakage of tissues in the inner part of the food and facilitating high grade cooking and to provide a food heater. <P>SOLUTION: The method for heating a food comprises a heating step to expose a food 90 to an atmosphere containing superheated steam 100 and heat the food 90 by the condensation heat generated by the contact of the surface of the food 90 with the superheated steam 100, and a step to remove water from the surface of the food 90. The method prevents the decrease of water content in the inner part of the food 90 in the thermal denaturation of the food component. The food heater further performs the heating method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a food heating method and a food heater, and more particularly to a food heating method and a food heater that can prevent high-quality cooking and easily destroy the tissue inside the food.

  The amount of water in the food is 50 to 50% for most foods, such as about 73% for beef, about 70% for fish, about 80% for squid, and about 79% for potatoes. This amount of water plays a large role in the formation of the tissue inside the food.

  Examples of conventional methods for heating food in business or home cooking include hot air heating in a hot air oven system using electricity or gas as a heat source, radiant heating in a radiant grill system, or electromagnetic wave heating in a microwave using a microwave. Etc. are used. However, in these heating methods, there is a problem that the heating of food progresses and moisture evaporates from the inside of the food, destroying the structure inside the food.

  In addition, as a method for heating food in cooking, there is a method using steam heating in which food is heated using steam that is not superheated steam. However, this heating method has a problem that the surface and the inside of the food are both sticky due to moisture, and high-quality cooking cannot be performed.

  Therefore, in recent years, food is put in a packaging bag such as a resin film before heating the food, the inside of the packaging bag is evacuated, the opening of the packaging bag is sealed, and the whole packaging bag is heated in hot water. Thus, a vacuum cooking method for cooking without evaporating moisture inside the food has been put into practical use.

  However, in this vacuum cooking method, it is necessary to put food in the packaging bag before heating the food and to make the inside of the packaging bag vacuum, which is very troublesome.

Patent Document 1 discloses a food processing method in which superheated steam is applied to food so that air is not mixed under normal pressure (for example, claims 1 to 5 of Patent Document 1). reference.). However, even in this method, there is a problem that the heating of the food progresses and moisture evaporates from the inside of the food, thereby destroying the tissue inside the food.
JP 2001-46005 A

  An object of the present invention is to provide a method for heating a food and a food heater that can easily make high-quality cooking because the structure inside the food is not easily destroyed.

  The present invention includes a process of heating the food by condensation heat generated by exposing the food to an atmosphere containing superheated steam and contacting the superheated steam on the surface of the food, and a process of removing moisture from the surface of the food. A method for heating a food, wherein the amount of water in the food is not reduced when the ingredients of the food are heat-denatured.

  Here, in the food heating method of the present invention, it is preferable that the time of heat denaturation of the components of the food is time of protein denaturation contained in the food.

  Moreover, in the heating method of the foodstuff of this invention, it is preferable that the temperature of superheated steam is 100 degreeC or more.

  Moreover, in the heating method of the foodstuff of this invention, it is preferable that superheated steam accounts for 50 volume% or more of atmosphere.

In the method for heating a food according to the present invention, the amount of superheated steam supplied to the atmosphere is preferably 0.1 cm ³ / min or more in terms of water content per liter of the atmosphere volume.

  Moreover, in the heating method of the foodstuff of this invention, it is preferable that superheated steam is supplied more to the center part of atmosphere compared with the edge part of atmosphere.

  Moreover, in the heating method of the foodstuff of this invention, it is preferable that the flow rate of the superheated steam which contacts the surface of foodstuff is 2 m / sec or more.

  In the food heating method of the present invention, it is preferable to heat the food with a heater after stopping the supply of superheated steam.

  Furthermore, the present invention is a food heater for carrying out the food heating method according to any one of the above, and includes a container for storing the food and a steam supply device connected to the container. It is a heater.

  INDUSTRIAL APPLICABILITY In the present invention, it is possible to provide a food heating method and a food heater that can prevent high-quality cooking from easily destroying the tissue inside the food.

  Hereinafter, embodiments of the present invention will be described. In the drawings of the present specification, the same reference numerals represent the same or corresponding parts.

  In FIG. 1, the expansion conceptual diagram for demonstrating a preferable example of the heating method of the foodstuff of this invention is shown. As shown in FIG. 1, in the present invention, when the food 90 is exposed to an atmosphere containing the superheated steam 100, the superheated steam 100 comes into contact with the surface of the food 90, and the superheated steam 100 changes to condensed water 101. Condensation heat generated is transmitted to the food 90 and heated, and convection heat generated by the convection of the superheated steam 100 in the atmosphere and radiant heat radiated from the high temperature superheated steam 100 are transmitted to the food 90 and heated. The In addition, superheated steam means the high temperature water vapor | steam which added heat further to saturated water vapor | steam and was 100 degreeC or more.

  On the other hand, in the conventional hot air heating, as shown in the enlarged conceptual diagram of FIG. 2, only the convection heat generated by the convection of the heated air 102 as hot air is transferred to the food 90.

  Therefore, as shown in the comparison diagram of FIG. 3, the food heating method of the present invention has a faster rise in the internal temperature of the food with respect to the heating time than the conventional hot air heating, and the food heating method is faster than the conventional hot air heating. Can be promoted.

  In FIG. 4, the figure which compared the amount of moisture change with respect to the heating time of the heating method of the foodstuff by the superheated steam of this invention, the heating method of the foodstuff by the conventional hot air heating, and the heating method of the foodstuff by steam heating is shown. In the method for heating food with superheated steam according to the present invention, the food is heated by the transmission of heat (condensation heat, convection heat, radiant heat) described above, and the condensed water of superheated steam soaks into the food. The amount of moisture on the surface and inside increases. Then, when a certain heating time has elapsed, this time, a recovery process is started in which moisture evaporates from the surface of the food and the amount of moisture decreases. And if heating time passes further, it will enter into the drying process in which the moisture content on the surface of a foodstuff decreases rather than the foodstuff before heating. The food heating method of the present invention that has undergone such a process enables high-quality cooking in which the surface of the food is crisp and the inside of the food is juicy.

  On the other hand, in hot air heating, the amount of moisture on the surface and inside of the food decreases from the start of heating the food, and both the surface and inside of the food are too dry. In addition, in steam heating, the amount of moisture on the surface and inside of the food increases from the start of heating the food, and the surface and inside of the food both stick.

  Here, the method for heating a food according to the present invention is characterized in that the amount of water in the food is not reduced when the ingredients of the food are heat-denatured. Ingredients other than water of food are proteins, carbohydrates, fats and oils, etc., and these are heated and undergo complicated changes such as denaturation by heat and oxidation reaction by oxygen. When this change occurs, the reduction of moisture, which accounts for the majority of food ingredients and plays a major role in the formation of tissues inside the food, will significantly destroy the tissues inside the food and dry the food inside. There is a problem that high-quality cooking is not possible. Therefore, such a problem is solved by not reducing the water content inside the food during the heat modification of the ingredients of the food.

  In the present specification, “at the time of heat denaturation of the food component” means not only when the protein of the food is denatured but also from a state where the food component is present to another state such as when fats and oils are oxidized. It also includes the case of changing to In particular, when the amount of water inside the food does not decrease when the protein contained in the food is denatured, the tissue inside the food is less likely to be destroyed. Preferably there is.

  FIG. 5 (A) shows a scanning electron microscope (SEM) photograph of the protein contained in the food before heating. The food is heated using the heating method according to the present invention and the conventional heating method using hot air heating. Then, in the heating method according to the present invention, the amount of water inside the food does not decrease when the protein is denatured, so that the tissue structure inside the food is maintained as shown in the SEM photograph of FIG. On the other hand, in the conventional heating method using hot air heating, the amount of water in the food is reduced when the protein is denatured. Therefore, as shown in the SEM photograph of FIG. As a result, the tissue structure inside the food is destroyed.

  In FIG. 6, the typical block diagram of a preferable example of the heater of the foodstuff used for this invention is shown. This heater includes a heating chamber 20 as a container for containing food, and a steam supply device 50 connected to the heating chamber 20.

  The heating chamber 20 has a rectangular parallelepiped shape, and one surface thereof is opened entirely. The open surface is in contact with a door (not shown). It is preferable that the inner surface of the heating chamber 20 and the inner surface of the door are formed of a stainless steel plate so as to withstand even when the inside of the heating chamber 20 becomes a high pressure. Moreover, it is preferable that a heat insulating material is installed around the heating chamber 20 and inside the door. In this case, the internal temperature of the heating chamber 20 is not easily affected by the outside of the heating chamber 20. A stainless steel plate tray 21 is installed on the floor of the heating chamber 20, and a stainless steel plate rack 22 for placing food is placed on the tray 21.

  Further, a stainless steel airflow control plate 23 is installed from the upper part of the heating chamber 20 so as to hang down near the floor of the heating chamber 20. Note that a gap between the end of the air flow control plate 23 on the floor surface side of the heating chamber 20 and the side wall of the heating chamber 20 serves as a gas suction port 24, and guides a gas containing superheated steam to the external circulation path 30.

  In FIG. 7, the typical expanded sectional view of a preferable example of the steam supply apparatus 50 used for this invention is shown. The steam supply device 50 includes a cylindrical pot 51, a steam generating heater 56 installed so as to be in close contact with the outer surface of the pot 51, a water supply pipe 63 that supplies water into the pot 51, a drain pipe 52, A heat transfer unit 60. A steam suction ejector 34 is formed on the top of the pot 51, and the steam suction ejector 34 includes a pipe 33 and a nozzle 35.

  The bottom of the pot 51 is formed in a funnel shape, and a drain pipe 52 hangs down from the bottom. The lower end portion of the drain pipe 52 is connected to a drain channel 53 shown in FIG. 6 arranged in a slightly inclined shape with respect to the horizontal. As shown in FIG. 6, the end of the drainage pipe 53 opens toward the tray 21 through the side wall of the heating chamber 20. A drain valve 54 and a water level sensor 55 are installed between the drain pipe 52 and the drain pipe 53. Further, the heat transfer unit 60 is installed inside the pot 51 so as to be almost the same height as the steam generating heater 56.

  The heat transfer unit 60 includes a ring 61 that is in close contact with the inner surface of the side wall of the pot 51, and a plurality of fins 62 that are radially installed inside the ring 61. The ring 61 and the fin 62 are integrated by a technique such as extrusion, welding, or brazing. The ring 61 and the fin 62 have a predetermined length in the axial direction of the pot 51.

  The pot 51, the heat transfer unit 60, and the water supply pipe 63 are preferably formed of a metal that is a good heat conductor. As the metal, copper, aluminum or the like having good thermal conductivity is suitable. However, in the case of copper or copper alloy, since patina is generated, it is possible to use stainless steel that does not worry about patina, although the thermal conductivity is slightly inferior.

  In such a steam supply device 50, first, water in the water tank 71 is pumped to the water supply pipe 63 from the water tank 71 shown in FIG. The pump 73 includes a pump casing 74, an impeller 75 housed in the pump casing 74, and a motor 76 that transmits power to the impeller 75. The motor 76 is electromagnetically coupled to the impeller 75 when the water tank 71 is set at a predetermined position.

  The water pumped to the water supply pipe 63 overflows like a fountain from the tip of the water supply pipe 63 and is supplied into the pot 51 as shown in FIG. When the water level sensor 55 detects that the water level has reached the middle of the length of the heat transfer unit 60, the supply of water is once stopped.

  Thus, after a predetermined amount of water is supplied into the pot 51, energization of the steam generating heater 56 is started. The steam generating heater 56 heats the water in the pot 51 through the wall surface of the pot 51. When the wall surface of the pot 51 is heated, the heat is transferred to the heat transfer unit 60 and is transferred from the heat transfer unit 60 to water. Since the installation location of the steam generating heater 56 and the installation location of the heat transfer unit 60 are substantially at the height, heat is transferred straight from the steam generation heater 56 to the heat transfer unit 60, and the heat transfer efficiency is improved.

  Simultaneously with energization to the steam generating heater 56, energization to the blower 25 and the steam heater 41 shown in FIG. 6 is also started. The blower 25 sucks the gas inside the heating chamber 20 from the gas suction port 24 and sends the gas to the external circulation path 30. Since the gas is sent out by the centrifugal fan 26, the gas flow rate is faster than that of the propeller fan. Further, when the centrifugal fan 26 is rotated at a high speed by a DC motor, the flow rate of the gas becomes extremely fast.

  Then, the water in the pot 51 boils and water vapor is generated. The water vapor is quickly sucked up by the steam suction ejector 34 and is ejected from the nozzle 35 to the rear-stage ejector 37.

  In the rear-stage ejector 37, the gas flowing from the bypass path 38 joins the water vapor ejected from the nozzle 35 of the steam suction ejector 34. The gas containing water vapor that has passed through the rear-stage ejector 37 enters the subcavity 40 at a high speed.

  The steam that has entered the subcavity 40 is heated by the steam heater 41 to become superheated steam. The superheated steam expands as the temperature rises, and is ejected vigorously from the air outlet 43 and supplied to the atmosphere inside the heating chamber 20.

  Here, the temperature of the superheated steam inside the heating chamber 20 is preferably 100 ° C. or higher, and more preferably 150 ° C. or higher. When the temperature of the superheated steam is 100 ° C. or higher, the water becomes completely gaseous, so that the amount of water vapor in the atmosphere inside the heating chamber 20 can be greatly increased, and the amount of condensed water adhering to the food surface can be reduced. Can be increased. In addition, when the temperature of the superheated steam is 150 ° C. or more, particularly high-quality cooking tends to be possible in cooking such as baking cooking.

Further, the amount of superheated steam supplied to the atmosphere inside the heating chamber 20 is set to 0. 0 in terms of the amount of moisture per liter of the volume (volume) of the atmosphere inside the heating chamber 20 from the viewpoint of not reducing the moisture content inside the food. It is preferably 1 cm ³ / min or more, and more preferably 0.3 cm ³ / min or more. Here, the supply amount of superheated steam is calculated by measuring the amount of water that decreases from the water tank 71 per minute and converting this to the volume per liter of the heating chamber 20.

  Further, it is preferable that a larger amount of superheated steam is supplied to the central portion than the end portion of the atmosphere inside the heating chamber 20. In this case, the amount of condensed water adhering to the surface of the food tends to increase, and the food can be efficiently heated.

  When the gas containing superheated steam is supplied into the heating chamber 20, the temperature inside the heating chamber 20 rises rapidly. When a temperature sensor (not shown) detects that the temperature inside the heating chamber 20 has reached the cookable region, the user is informed that cooking has become possible by means of display or sound. Then, the user opens the door and installs the food 90 inside the heating chamber 20.

  Then, the superheated steam blown down from the air outlet 43 comes into contact with the surface of the food 90, and the food 90 is heated by the condensation heat, convection heat and radiant heat of the superheated steam being transmitted to the food 90 as described above.

Here, the superheated steam preferably occupies 50% by volume or more of the atmosphere inside the heating chamber 20, and more preferably 90% by volume or more. When the superheated steam occupies 50% by volume or more of the atmosphere inside the heating chamber 20, the amount of condensed water adhering to the food 90 is increased and the heating rate of the food 90 is increased. Since the movement time of moisture until time is shortened, the tissue inside the food 90 tends to be more difficult to be destroyed. In addition, since the oxygen concentration in the atmosphere also decreases, it tends to be able to suppress the denaturation of food components that are easily oxidized. In particular, when the superheated steam occupies 90% by volume or more of the atmosphere inside the heating chamber 20, these tendencies are further increased. Note that the ratio of superheated steam occupying the atmosphere inside the heating chamber 20 can be calculated from, for example, an oxygen concentration measured by installing an oxygen concentration meter inside the heating chamber 20. That is, when the atmosphere inside the heating chamber 20 is composed of air and superheated steam, the oxygen concentration in the air is about 20%, so the atmosphere inside the heating chamber 20 is

The ratio of the air in the atmosphere is about four times the oxygen concentration measured by the oximeter, and components other than air become superheated steam. Therefore, the ratio of superheated steam in the atmosphere inside the heating chamber 20 is expressed by the following formula.
Percentage of superheated steam (%) = 100 (%) − 4 × (oxygen concentration (%) measured by oxygen analyzer)
Further, the flow rate of the superheated steam contacting the surface of the food 90 is preferably 2 m / second or more, and more preferably 5 m / second or more. When the flow rate of the superheated steam is less than 2 m / sec, the amount of condensed water adhering to the food 90 tends to decrease and the heat transfer efficiency tends to deteriorate. Moreover, when the flow rate of superheated steam is 5 m / sec or more, the amount of condensed water attached to the food 90 increases, and in particular, heat transfer efficiency is improved, and oil on the surface of the food 90 is efficiently removed. Tend to be able to. Note that the flow rate of superheated steam that contacts the surface of the food 90 is measured, for example, by installing a propeller-type anemometer in the vicinity of the food 90.

  After the superheated steam collides with the food 90, the direction of the superheated steam is turned upward to the heating chamber 20. Since superheated steam is lighter than air, it turns in this way in a natural way, which causes convection inside the heating chamber 20. By this convection, while maintaining the temperature inside the heating chamber 20, the food 90 can be made to collide with the superheated steam just heated in the subcavity 40, and heat can be given to the food 90 in a large amount and quickly. .

  If the steam generator 50 continues to generate saturated water vapor, the water level in the pot 51 decreases. When the water level sensor 55 detects that the water level has dropped to a predetermined level, the control device restarts the operation of the pump 73. The pump 73 pushes up the water in the water tank 71 and replenishes the evaporated water. Then, when the water level sensor 55 detects that the water inside the pot 51 has reached a predetermined level, the control device stops the operation of the pump 73. In this way, the pump 73 can perform a water supply operation intermittently during the cooking period.

  In the above, a heater (not shown) can be installed inside or outside the heating chamber 20, and after the supply of superheated steam to the heating chamber 20 is stopped, the food 90 can be heated by the heater. it can. In this case, because the surface of the food 90 can be burnt, such as burnt eyes, the commercial value of the processed food tends to be advantageous.

Example 1
Using the food heater shown in FIG. 6, superheated steam at 230 ° C. is supplied to the inside of the heating chamber 20 at a rate of 11.5 cm ³ / min in terms of water content per liter of the volume of the atmosphere inside the heating chamber 20. Further, 90% by volume of the atmosphere inside the heating chamber 20 was occupied by superheated steam. Here, when the ham is installed on the rack 22 as the food 90 in the central portion of the heating chamber 20, the superheated steam is supplied more to the central portion of the heating chamber 20 than in the vicinity of the side wall of the heating chamber 20, and the ham surface. The flow rate of the superheated steam in contact was 3 m / sec. Then, the ham was heated and the mass change of the surface and the inside of the ham heated for a predetermined time was measured, and the temperature of the surface and the inside of the ham were measured. The longest heating time was the time when the internal temperature of the ham reached 85 ° C. FIG. 8 shows the relationship between the temperature change and mass change on the surface and inside of the ham during this heating and the elapsed time.

  As shown in FIG. 8, in Example 1, the elapsed time until the internal temperature of the ham reached 85 ° C. was as short as about 22 minutes. This is considered to be because the ham was efficiently heated by the condensation heat, the convection heat, and the radiant heat by the superheated steam in Example 1.

  As shown in FIG. 8, in Example 1, the mass of the ham surface decreased during heating, but the mass inside the ham did not decrease compared to before heating. This is thought to be because the amount of water in the ham was not reduced by the superheated steam.

  In Example 1, the change in the mass of the food surface and the inside was measured before and after heating by stacking three hams of the same shape vertically, with the upper and lower hams on the surface and the middle ham inside. Was measured by comparing. The temperature change of the food surface and inside was measured by inserting a thermocouple with the center of the upper ham out of the three hams stacked in the same manner as above and the center of the middle ham inside. It was.

(Comparative Example 1)
Without using the food heater shown in FIG. 6, the ham was heated by hot air heating at 230 ° C., and the change in the mass of the surface and the inside of the ham heated for a predetermined time was measured, and the temperature of the surface and the inside of the ham was measured. did. The longest heating time was the time when the internal temperature of the ham reached 85 ° C. FIG. 8 shows the relationship between the temperature change and mass change on the surface and inside of the ham during this heating and the elapsed time.

  As shown in FIG. 8, in Comparative Example 1, it took about 28 minutes for the internal temperature of the ham to reach 85 ° C. This is considered to be because in Comparative Example 1, the ham could not be efficiently heated because it was heating only by the convection heat of the hot air.

  Moreover, as shown in FIG. 8, in the comparative example 1, both the surface and internal mass of ham decreased during heating compared with before heating. This is probably because the ham was heated by hot air containing almost no moisture.

(Example 2)
Heating with superheated steam was performed in the same manner as in Example 1 except that 250 ° C superheated steam was supplied into the heating chamber 20 shown in Fig. 6 and the frozen bread was heated instead of ham. And while measuring the mass change of the surface and the inside of the frozen bread which heated for the predetermined time, the surface and the internal temperature of the frozen bread were measured. FIG. 9 shows the relationship between the temperature change and mass change on the surface and inside of the bread during this heating and the elapsed time.

  As shown in FIG. 9, in Example 2, it was confirmed that the mass inside the bread was increased for 6 minutes from the start of heating. From the situation of Example 2, this increase is considered to be an increase in moisture. In addition, when the temperature change inside the bread shown in FIG. 9 is seen, the temperature suddenly rises in 3 to 6 minutes from the start of heating. Therefore, it is considered that the heat denaturation of the ingredients inside the bread is taking place during this time. Therefore, in Example 2, it is considered that the amount of water inside the bread is not reduced during the heat denaturation of the ingredients inside the bread.

(Comparative Example 2)
Without using the food heater shown in FIG. 6, the frozen bread was heated by hot air heating at 250 ° C., and the mass change of the surface and the inside of the frozen bread that was heated for a predetermined time was measured. The temperature was measured. FIG. 9 shows the relationship between the temperature change and mass change on the surface and inside of the frozen bread during this heating and the elapsed time.

  As shown in FIG. 9, in Comparative Example 2, the amount of water inside the bread continued to decrease immediately after the start of heating. Therefore, it is considered that the increase in the amount of water inside the bread of Example 2 shown in FIG. 9 described above is not the water generated when the frozen bread is heated, but the condensed water of superheated steam.

(Example 3)
Fish was cooked under the same conditions as in Example 1 using the food heater shown in FIG. The photograph of the fish after baking cooking is shown in FIG. In FIG. 10, the fish placed on the left plate is the fish that has been baked and cooked in the third embodiment. As shown in FIG. 10, the fish after baking cooked according to Example 3 had a baked color on the entire surface, had no local charring, and had a plump interior.

(Comparative Example 3)
A grilled fish was cooked using a conventional grill cooker without using the food heater shown in FIG. The photograph of the fish after baking cooking is shown in FIG. In FIG. 10, the fish placed on the right plate is the fish that has been baked and cooked in Comparative Example 3. As shown in FIG. 10, the fish after grilled cooking had a conspicuous spot on the surface compared to the fish of Example 3 on the left side dish, and the inside was not finished smoothly.

Example 4
The squid was baked and cooked under the same conditions as in Example 1 using the food heater shown in FIG. A photograph of the squid after baking is shown in FIG. As shown to FIG. 11 (A), the squid after baking cooking was finished plumply, without contracting.

(Comparative Example 4)
Without using the food heater shown in FIG. 6, the grilled squid was cooked using a conventional grill cooker. A photograph of the squid after baking is shown in FIG. As shown in FIG. 11 (B), the squid after grilled cooking contracted compared to the squid of Example 4 shown in FIG. 11 (A), and did not finish plumply.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  In the present invention, it is possible to provide a food heating method and a food heater capable of facilitating high-quality cooking because the tissue inside the food is not easily destroyed. Therefore, the present invention provides meat storage, fish meat, and seafood. It is suitably used for grilling (baking) foods such as potatoes and vegetables, oven cooking, warm cooking, cooking with steam or steaming. The present invention is also suitably used for boiled egg cooking or fried egg cooking.

It is an expansion conceptual diagram for demonstrating a preferable example of the heating method of the foodstuff of this invention. It is an expansion conceptual diagram for demonstrating an example of the heating method of the foodstuff by the conventional hot air heating. It is a comparison figure of the change of the food internal temperature with respect to the heating time of the heating method of the foodstuff by the superheated steam of this invention, and the heating method of the foodstuff by the conventional hot air heating. It is a comparison figure of the moisture change amount with respect to the heating time of the heating method of the foodstuff by the superheated steam of this invention, the heating method of the foodstuff by the conventional hot air heating, and the heating method of the foodstuff by steam heating. (A) is a SEM photograph of the protein contained in the food before heating, (B) is a SEM photograph of the protein contained in the food after heating by the heating method of the present invention, and (C) is a conventional hot-air heating. It is a SEM photograph of the protein contained in the foodstuff after heating by. It is a typical block diagram of a preferable example of the heater of the foodstuff used for this invention. It is a typical expanded sectional view of a preferable example of the steam supply apparatus used for this invention. In Example 1 and Comparative Example 1, it is the figure which showed the relationship between the temperature change and mass change in the surface of ham, and the inside, and elapsed time. In Example 2 and Comparative Example 2, it is the figure which showed the relationship between the temperature change and mass change, and elapsed time in the surface and the inside of a bread when heating frozen bread. In Example 3 and Comparative Example 3, it is the photograph of the fish after baking. (A) is a photograph of the squid after baking in Example 4, and (B) is a photograph of the squid after baking in Comparative Example 4.

Explanation of symbols

20 heating chamber, 21 saucer, 22 rack, 23 airflow control plate, 24 gas suction port, 25 air blower, 26 centrifugal fan, 30 external circulation path, 33 pipe, 34 steam suction ejector, 35 nozzle, 37 rear ejector, 38 bypass Path, 40 subcavity, 41 steam heater, 43 fumarole, 50 steam supply device, 51 pot, 52
Drainage pipe, 53 Drainage channel, 54 Drainage valve, 55 Water level sensor, 56 Steam generating heater, 60 Heat transfer unit, 61 Ring, 62 Fin, 63 Water supply pipe, 71 Water tank, 73 Pump, 74 Pump casing, 75 Impeller, 76 Motor, 90
Food, 100 superheated steam, 101 condensed water.

Claims (9)

  A process of heating the food by condensation heat generated by exposing the food to an atmosphere containing superheated steam and contacting the surface of the food with superheated steam, and a process of removing moisture from the surface of the food A method for heating food, wherein the amount of water inside the food is not reduced when the ingredients of the food are heat-denatured.   The method for heating a food according to claim 1, wherein the time when the ingredients of the food are heat-denatured is when the protein contained in the food is denatured.   The method for heating food according to claim 1 or 2, wherein the temperature of the superheated steam is 100 ° C or higher.   The method for heating food according to any one of claims 1 to 3, wherein the superheated steam occupies 50% by volume or more of the atmosphere. The supply amount of the superheated steam to the atmosphere is 0.1 cm ³ / min or more in terms of water amount per liter of volume of the atmosphere, The food according to any one of claims 1 to 4, Heating method.   The method for heating a food according to any one of claims 1 to 5, wherein the superheated steam is supplied more to a central portion of the atmosphere than to an end portion of the atmosphere.   The method for heating a food product according to any one of claims 1 to 6, wherein a flow rate of the superheated steam contacting the surface of the food product is 2 m / sec or more.   The method for heating food according to any one of claims 1 to 7, wherein the food is heated by a heater after the supply of the superheated steam is stopped. A food heater for carrying out the method for heating food according to any one of claims 1 to 8, comprising a container for containing food and a steam supply device connected to the container. Characteristic food heater.

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