Heating unit, method for manufacturing food, and food

Abstract

The present invention provides a heating unit and a food manufacturing method that can suppress the occurrence of temperature differences inside food when heating food by applying electricity. [Solution] According to the present invention, a heating unit is provided, comprising a cylindrical body, a first planar electrode, a second planar electrode, and a conductive thin film, wherein the cylindrical body is configured to be filled with conductive food, the first planar electrode and the second planar electrode are configured to be positioned on both sides of the food filled in the cylindrical body so as to seal the food, and the conductive thin film is provided in a strip shape along the circumferential direction at a position between the first planar electrode and the second planar electrode on the inner circumferential surface of the cylindrical body, and the heating unit is configured to heat the food by supplying an electric current to the food from the first planar electrode and the second planar electrode.

Description

Technical Field

[0001] The present invention relates to a heating unit, a method for manufacturing food, and food.

Background Art

[0002] Patent Document 1 discloses a technique of passing electric current through a meat material (ham log) filled in an artificial casing while sandwiching it with a pair of electrodes with a predetermined pressure from both outer sides in the longitudinal direction. By using electric current heating, it is said that food can be heated in a short time and uniformly.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <> When an electrically conductive food such as a meat material is placed between a pair of electrodes and heated by passing an electric current, the outside of the food radiates heat more easily than the inside. When a temperature difference occurs inside the food due to heat radiation from the outside of the food, the conductivity of the hot part increases and it becomes easier to be heated, while the conductivity of the cold part relatively decreases and it becomes difficult to be heated. As a result, the temperature difference between the outside and the inside of the food may accelerate and spread. For homogeneous processing, it is important to heat the food as uniformly as possible so that no temperature difference occurs inside the food when passing an electric current through it.

[0005] The present invention has been made in view of such circumstances, and provides a heating unit, a method for manufacturing food, and food capable of suppressing the occurrence of a temperature difference inside the food when passing an electric current through the food.

Means for Solving the Problems

[0006] The present invention provides the following: [1] A heating unit comprising a cylindrical body, a first planar electrode, a second planar electrode, and a conductive thin film, wherein the cylindrical body is configured to be filled with conductive food, the first planar electrode and the second planar electrode are configured to be positioned on both sides of the food filled in the cylindrical body so as to seal the food, and the conductive thin film is provided in a strip shape along the circumferential direction on the inner circumferential surface of the cylindrical body at a position between the first planar electrode and the second planar electrode, and the heating unit is configured to heat the food by supplying an electric current to the food from the first planar electrode and the second planar electrode. A heating unit according to [2][1], wherein the conductive thin film has a longitudinal width of the cylindrical body that is 20-70% of the distance between the first planar electrode and the second planar electrode. A heating unit according to [3][1] or [2], wherein the conductive thin film is arranged in a plurality in the longitudinal direction of the cylindrical body. A heating unit according to any one of items [4][1] to [3], wherein the first planar electrode and the second planar electrode are configured to be movable along the longitudinal direction of the cylindrical body while sliding on the inner circumferential surface of the cylindrical body, and are configured to pass through the position where the conductive thin film is arranged. A method for manufacturing food using a heating unit described in any one of items [5][1] to [4], comprising a clamping step and a heating step, wherein in the clamping step, conductive food made of a protein-containing material is placed in the heating space inside the cylindrical body, and the food is clamped between the first planar electrode and the second planar electrode, and in the heating step, the first planar electrode and the second planar electrode move to positions on both sides of the conductive thin film in the longitudinal direction of the cylindrical body, respectively, while the food is still clamped, and the food clamped in the clamping step is heated by applying an electric current to a predetermined heating temperature. Food manufactured by the food manufacturing method described in [6][5]. [Effects of the Invention]

[0007] According to the heating device of the present invention, when food is filled inside a cylindrical body and heated by applying an electric current using a first planar electrode and a second planar electrode, a conductive thin film is placed on the inner circumferential surface of the cylindrical body that is in contact with the outside of the food. Since the conductive thin film has a lower electrical resistance than the food, current flows more easily through the conductive thin film between the first planar electrode and the second planar electrode, and the heating of the food is promoted along this path. As a result, the heat dissipation from the outside of the food is compensated for, and the generation of temperature differences inside the food is suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of a processing apparatus 1 according to one embodiment of the present invention. [Figure 2] This is a schematic longitudinal cross-sectional view passing through the center of the processing apparatus 1 in Figure 1. [Figure 3] Figure 3A is a perspective view showing an example of the arrangement of the conductive thin film 25 in the heating unit 2, and Figure 3B is a longitudinal cross-sectional view showing an example of the arrangement of the conductive thin film 25 in the heating unit 2. [Figure 4] Figure 4A shows the initial position of the first planar electrode 21A and the second planar electrode 21B. Figure 4B shows the state in which the food 50 is pressurized by the first planar electrode 21A and the second planar electrode 21B. Figure 4C shows the state in which the food 50 is electrically heated by the first planar electrode 21A and the second planar electrode 21B. Figure 4D shows the state in which the food 50 has been moved to the cooling space 10B by the first planar electrode 21A and the second planar electrode 21B. Figure 4E shows the state in which the food 50 has been transported to the discharge position by the first planar electrode 21A and the second planar electrode 21B. [Figure 5] Figure 5A shows an example in which a single conductive thin film 25 is provided at a position equidistant from both the first planar electrode 21A and the second planar electrode 21B. Figure 5B shows an example in which one conductive thin film 25 is provided near the first planar electrode 21A and one near the second planar electrode 21B. Figure 5C shows an example in which a conductive thin film 25 is provided at three locations: the center between the first planar electrode 21A and the second planar electrode 21B, near the first planar electrode 21A, and near the second planar electrode 21B. [Figure 6]Figure 6A shows the arrangement for the electrical heating test in Example 1, Figure 6B shows the arrangement for the electrical heating test in Example 2, and Figure 6C shows the arrangement for the electrical heating test in Example 3. [Figure 7] Figure 7 shows the setup for the electrical heating test in Example 4. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature constitutes an independent invention.

[0010] <Overview of Heating Unit 2> As shown in Figures 1 and 2, the processing apparatus 1 comprises a heating unit 2 and a cooling unit 3. The heating unit 2 comprises a first cylindrical body 20 and a first planar electrode 21A and a second planar electrode 21B. The first cylindrical body 20 is configured to be filled with conductive food 50. The first planar electrode 21A and the second planar electrode 21B are each configured to slide along the longitudinal direction of the first cylindrical body 20 on the inner circumferential surface of the first cylindrical body 20. In this invention, for convenience, the direction in which the first planar electrode 21A and the second planar electrode 21B slide is referred to as the longitudinal direction of the first cylindrical body 20 (which may also be called the axial direction). The first planar electrode 21A and the second planar electrode 21B are configured to be positioned on both sides of the food 50 filled in the first cylindrical body 20 so as to seal the food 50. In the heating unit 2, the food 50 is heated by supplying current to the food 50 from the first planar electrode 21A and the second planar electrode 21B.

[0011] As shown in Figures 3A and 3B, the heating unit 2 further includes a conductive thin film 25. The conductive thin film 25 is provided in a strip shape along the circumferential direction of the first cylindrical body 20, at a position between the first planar electrode 21A and the second planar electrode 21B on the inner circumferential surface of the first cylindrical body 20. Since the conductive thin film 25 is positioned in contact with the food 50, it is preferable to use a metal that is appropriate under the Food Sanitation Law, such as iron, aluminum, platinum, and titanium. Here, an aluminum or titanium thin film (about 0.1 mm thick) is used as the conductive thin film 25. The aluminum thin film has the advantages of being inexpensive and easy to install and having excellent conductivity (resistivity: about 2.7 μΩ·cm). The titanium thin film has the advantages of excellent durability and strength. The conductivity of titanium is about 42 μΩ·cm, which is about 1 / 16th the conductivity of the aluminum thin film. Therefore, for example, in situations other than those requiring durability and strength, where a less stringent compensation for heat dissipation is desired than with an aluminum thin film, it is advisable to use a titanium thin film.

[0012] In the processing apparatus 1, considering that the position of the conductive thin film 25 is moved by sliding the first planar electrode 21A and the second planar electrode 21B, it is preferable that the conductive thin film 25 be positioned in a recessed position on the inner surface of the first cylindrical body 20 so that it lies on the same plane as the inner surface of the first cylindrical body 20. In this embodiment, since this configuration is adopted, the first planar electrode 21A and the second planar electrode 21B are able to move along the longitudinal direction of the first cylindrical body 20 while sliding on the inner surface of the first cylindrical body 20. The first planar electrode 21A and the second planar electrode 21B can also pass over the position of the conductive thin film 25 without any obstruction. However, the method of installing the conductive thin film 25 is not limited to this, and when using an ultra-thin aluminum tape or an ultra-thin titanium sheet (for example, with a thickness of 0.1 mm or less) as the conductive thin film 25, it is also possible to attach it directly to the inner surface of the first cylindrical body 20 without creating a recess.

[0013] By providing the conductive thin film 25, when a current is passed with the food 50 sandwiched between the first planar electrode 21A and the second planar electrode 21B, the current easily flows along the inner peripheral surface of the first cylindrical body 20. As a result, the vicinity of the conductive thin film 25 in the food 50 is easily heated by energization heating. Therefore, even when the outside of the food 50 dissipates heat, the outside (near the surface) of the food 50 is easily maintained at approximately the same temperature as the inside of the food 50.

[0014] It is preferable that the width in the longitudinal direction of the first cylindrical body 20 (when there are a plurality of conductive thin films 25, the total width thereof) W of the conductive thin film 25 is 20 to 70% of the distance L between the first planar electrode 21A and the second planar electrode 21B. Specifically, W / L is, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70%, and may be within the range between any two of the values exemplified herein. For example, when the distance between the first planar electrode 21A and the second planar electrode 21B is 150 mm, the width in the longitudinal direction of the first cylindrical body 20 is preferably 30 to 105 mm. The reason is to prevent the current from flowing excessively along the inner peripheral surface of the first cylindrical body 20 and to prevent the outside of the food 50 from being excessively heated.

[0015] However, although the food 50 located between the first planar electrode 21A and the second planar electrode 21B and the conductive thin film 25 is heated by energization, the part of the food 50 in contact with the conductive thin film 25 is hardly energized. Therefore, when a wide conductive thin film 25 is arranged, the part of the food 50 in contact with the conductive thin film 25 may not be sufficiently heated. For this reason, it is preferable that a plurality of conductive thin films 25 are arranged along the longitudinal direction of the first cylindrical body 20. The number of the conductive thin films 25 is, for example, 1 to 20, and preferably 2 to 10. Specifically, this number is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and may be within the range between any two of the values exemplified herein (e.g., 3 to 8, 4 to 7, etc.).

[0016] If Wa is the average width of each conductive thin film 25, then Wa / L is, for example, 1 to 20%, and preferably 3 to 10%. Specifically, Wa / L is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20%, and may be in the range between any two of the values ​​exemplified here. The value of Wa is, for example, 1 to 30 mm, and preferably 5 to 15 mm. Specifically, this value is, for example, 1, 3, 5, 10, 15, 20, 25, 30 mm, and may be in the range between any two of the values ​​exemplified here. When multiple conductive thin films 25 are arranged with an appropriate distance between them between the positions of the first planar electrode 21A and the second planar electrode 21B during heat treatment, it can be expected that the outside of the food 50 will be heated more uniformly in the longitudinal direction of the first cylindrical body 20. If Sa is the average value of the spacing between adjacent conductive thin films 25, then Sa / Wa is, for example, 0.5 to 10, and preferably 1.0 to 5.0. Specifically, Sa / Wa is, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10, and may also be in the range between any two of the values ​​exemplified here.

[0017] Furthermore, if Ss is the standard deviation of the spacing between adjacent conductive thin films 25, the coefficient of variation determined by Ss / Sa is preferably 50% or less, and more preferably 30% or less. The value of Ss / Sa is, for example, 0 to 50%, specifically, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50%, and may be in the range between any two of the values ​​exemplified here.

[0018] The first cylindrical body 20 of the heating unit 2 is preferably made of a material with a low coefficient of thermal expansion, high pressure resistance at high temperatures, low thermal conductivity, and excellent electrical insulation properties. By making the first cylindrical body 20 from such a material, it is possible to withstand the saturated water vapor pressure generated by energizing and heating the food 50, and it is also possible to prevent leakage of electricity that may occur during the energizing and heating of the food 50. The first cylindrical body 20 may be made of a super engineering plastic with heat resistance such as PEEK (PolyEtherEtherKetone), for example. Also, in order to achieve greater safety, as shown in FIG. 2, it is preferable to adopt a double structure in which the outside of the first cylindrical body 20 is covered with a metal outer cover 20A.

[0019] Further, a vacuum hole 20B is formed in the heating unit 2, and the heating unit 2 may be provided with a vacuum driving unit (not shown) such as a vacuum pump. The vacuum hole 20B can be formed, for example, on the side surface of the first cylindrical body 20. Here, the vacuum hole 20B is formed through the first cylindrical body 20 and the outer cover 20A. The heating unit 2 is configured such that the inside of the heating space 10A can be vacuum-treated from the outside of the heating unit 2 through the vacuum hole 20B by a vacuum driving unit or the like.

[0020] The vacuum hole 20B can be provided at any location as long as the food 50 before energizing and heating can be vacuum-treated. The vacuum driving unit can use any component as long as it can perform the vacuum treatment as described above.

[0021] <Cooling unit 3> The cooling unit 3 includes a second cylindrical body 30 that is continuous with the first cylindrical body 20 of the heating unit 2. Food 50 heated in the heating unit 2 is sent to the cooling unit 3 while being held between the first planar electrode 21A and the second planar electrode 21B. The cooling unit 3 has the function of cooling the food 50. As shown in Figure 2, the cooling unit 3 is connected to the heating unit 2 in the vertical direction. The internal space 10 formed by the first cylindrical body 20 and the second cylindrical body 30 is continuous through the heating unit 2 and the cooling unit 3, becoming the heating space 10A in the heating unit 2 and the cooling space 10B in the cooling unit 3.

[0022] The second cylindrical body 30 of the cooling unit 3 is preferably made of a material with high thermal conductivity in order to efficiently cool the food 50. The second cylindrical body 30 is preferably made of a metal such as SUS304. Furthermore, the cooling unit 3 is preferably equipped with a jacket portion 31 through which a refrigerant (e.g., chilled water) can circulate. The jacket portion 31 makes it possible to cool the food 50 in the cooling space 10B more efficiently.

[0023] <First planar electrode 21A and second planar electrode 21B> The first planar electrode 21A and the second planar electrode 21B are configured to electrically heat the food 50 sandwiched between them by utilizing the voltage applied from a power supply unit (not shown). Since the first planar electrode 21A and the second planar electrode 21B come into contact with the food 50, it is preferable to use metals that are appropriate under the Food Sanitation Law, such as iron, aluminum, platinum, and titanium. In this case, stainless steel or titanium is used as the material for the first planar electrode 21A and the second planar electrode 21B.

[0024] Highly conductive objects to be heated can be heated rapidly and uniformly by using electric heating. Typically, the food 50 to be subjected to electric heating is highly conductive because it is mixed with an aqueous solution containing an electrolyte. The power supply unit preferably includes an electronic circuit capable of supplying alternating current to the electrodes and measuring the impedance of the food 50 sandwiched between the electrodes. The power supply unit is preferably configured to supply alternating current of up to 10 kHz according to commands from, for example, a voltage control unit.

[0025] Furthermore, the first planar electrode 21A and the second planar electrode 21B are configured to move along their longitudinal direction within the internal space 10 formed by the first cylindrical body 20 and the second cylindrical body 30 while the food 50 is held between them. Specifically, the first planar electrode 21A and the second planar electrode 21B are configured to move from the heating space 10A to the cooling space 10B or to the outside of the internal space 10. The first planar electrode 21A and the second planar electrode 21B may be moved by, for example, an air cylinder.

[0026] The first planar electrode 21A and the second planar electrode 21B are each provided with sealing members 22A and 22B on their outer circumferences. The sealing members 22A and 22B make it easier to seal the food 50 filled in the first cylindrical body 20 with the first planar electrode 21A and the second planar electrode 21B. Since the first planar electrode 21A and the second planar electrode 21B can form a sealed state as needed, it becomes possible to properly vacuum the food 50 using the vacuum hole 20B and to prevent moisture contained in the food 50 from escaping during electric heating.

[0027] It is preferable that the first planar electrode 21A and the second planar electrode 21B each have fine irregularities on the contact surface with the food 50. For example, fine embossing is preferable. With such a configuration, the food 50 can be clamped more securely.

[0028] <First temperature sensor 40A and second temperature sensor 40B> The processing apparatus 1 further includes a first temperature sensor 40A and a second temperature sensor 40B. The first temperature sensor 40A is configured to detect the surface temperature of the food 50 when it is placed in the heating space 10A. The second temperature sensor 40B is configured to detect the surface temperature of the food 50 when it is placed in the cooling space 10B. The first temperature sensor 40A and the second temperature sensor 40B can, for example, employ ungrounded sheathed thermocouples.

[0029] <Operation of processing device 1: Method for manufacturing food 50> <Initial state> Next, the operation of the processing apparatus 1 will be explained using Figures 4A to 4E. As shown in Figure 4A, the initial state is when the first planar electrode 21A is located above the first cylindrical body 20 and the second planar electrode 21B is located in the internal space 10. In the initial state, food 50 is filled between the first planar electrode 21A and the second planar electrode 21B inside the first cylindrical body 20.

[0030] <Pinching process> Next, as shown in Figure 4B, the food 50 is sandwiched between the first planar electrode 21A and the second planar electrode 21B. Here, we show an example where only the first planar electrode 21A moves downward while the second planar electrode 21B remains fixed, but both the first planar electrode 21A and the second planar electrode 21B may be moved as needed.

[0031] When the first planar electrode 21A and the second planar electrode 21B begin to come into contact with the food 50, the first planar electrode 21A and the second planar electrode 21B are moved based on pressure data obtained from a pressure sensor or the like so that the pressure applied to the protein-containing material becomes a predetermined surface pressure, thereby compacting the food 50. Specifically, the predetermined surface pressure is 0.5 MPa or less, preferably 0.3 MPa or less. The predetermined surface pressure is, for example, 0.1 to 0.5 MPa, specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5 MPa, and may be within the range of any two of the values ​​exemplified here. When the pressure applied to the food 50 reaches the predetermined surface pressure, the movement of the first planar electrode 21A and the second planar electrode 21B stops. At this time, vacuum treatment may be performed as appropriate if necessary.

[0032] <Heating process> Next, as shown in Figure 4C, the first planar electrode 21A and the second planar electrode 21B move to both sides of the location where the conductive thin film 25 is placed on the inner circumference of the first cylindrical body 20, and perform an electric heating treatment on the food 50. The electric heating treatment is preferably performed using alternating current of a predetermined frequency. The predetermined frequency can be the commercial frequency of 50 Hz or 60 Hz. Alternatively, the predetermined frequency may be the frequency at which the impedance of the food 50 is minimized, or the frequency at which maximum heat generation can be expected, including dielectric loss. The electric heating is performed based on the temperature data obtained from the first temperature sensor 40A until the temperature of the food 50 reaches the predetermined heating temperature.

[0033] Furthermore, the predetermined heating temperature is preferably above the glass transition temperature (Tg) of the protein. Proteins begin to plasticize at temperatures above their glass transition temperature (Tg), causing adjacent proteins to fuse together. This thermal fusion of proteins can further increase the strength of the protein-containing material and alter its texture. The glass transition temperature (Tg) varies depending on the material and moisture content, but for protein materials used in the food industry, it is typically 80°C or higher, and generally 110°C or higher. Also, since protein hydrolysis and thermal decomposition progress as the temperature approaches 200°C, it is preferable that the temperature be below 200°C. Therefore, the predetermined heating temperature is 80 to 200°C, preferably 110 to 200°C. Specifically, the predetermined heating temperature can be, for example, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200°C, and may be within the range of any two of the values ​​exemplified here.

[0034] <Cooling process> When the electric heating stops, as shown in Figure 4D, the first planar electrode 21A and the second planar electrode 21B move to the cooling unit 3 while still holding the food 50. In the cooling unit 3, the food 50 is cooled to a predetermined cooling temperature. The predetermined cooling temperature is 100°C or lower. The predetermined cooling temperature is, for example, 10 to 100°C, preferably 70 to 100°C. Specifically, the predetermined cooling temperature is, for example, 10, 20, 30, 40, 50, 60, 70, 75, 80, 85, 90, 95, 100°C, and may be within the range of any two of the values ​​exemplified here.

[0035] <Discharge process> When the temperature data acquired from the second temperature sensor 40B reaches a predetermined cooling temperature, as shown in Figure 4E, the first planar electrode 21A and the second planar electrode 21B move further down the cooling unit 3 while still holding the food 50, and move to the outside of the processing device 1. In this state, the food 50, which has completed a series of processes, can be recovered. The recovered food 50 is cut into the desired size as appropriate and packaged.

[0036] As described above, in the processing apparatus 1 of this embodiment, during the electrical heating treatment of the food 50, the presence of the conductive thin film 25 on the inner circumferential surface of the first cylindrical body 20 creates a state in which the outside (surface) of the food 50 is easily heated by electrical conduction, thus making it less likely for a temperature difference to occur between the outside (surface) and the inside of the food 50. In particular, even when the diameter of the food 50 is increased, it is possible to heat it uniformly by electrical heating while preventing the occurrence of temperature differences in the radial direction.

[0037] <50 conductive food products> The conductive food 50 handled in the processing apparatus 1 and food 50 manufacturing method according to one embodiment of the present invention is, for example, any food material containing protein (protein-containing material). Specifically, a protein-containing material refers to a material in which the protein content is 1% by mass or more, preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more. The protein content in the protein-containing material is, for example, 1 to 100% by mass, specifically, for example, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100% by mass, and may be within the range of any two of the values ​​exemplified here.

[0038] In a method for producing food 50 according to one embodiment of the present invention, a protein-containing material is produced by adding an aqueous solution containing electrolytes such as salts to a dried protein-containing material of any shape and mixing the two solutions. In this specification, the protein-containing material before adding the aqueous solution containing electrolytes and mixing the two solutions is referred to as the dried protein-containing material. Next, the protein-containing material is heated by applying an electric current. This allows the dried protein-containing material to be reshaped and its quality to be transformed into a material with a moist and flexible texture. Therefore, the effects of the present invention are more effectively realized by using a material with poor processing properties such as water solubility and binding ability as the dried protein-containing material.

[0039] The water content of the dried protein-containing material is 50% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less. The water content of the dried protein-containing material may be substantially 0. The water content of the dried protein-containing material is, for example, 0 to 50% by mass, specifically, for example, 0, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50% by mass, and may be within the range of any two of the values ​​exemplified here.

[0040] <Other Embodiments> Although an example has been described in which the first planar electrode 21A and the second planar electrode 21B move inside the first cylindrical body 20, the present invention can also be applied to electrically heated devices and the like in which electrodes are provided at the bottom and top of the cylindrical body, respectively. In the embodiments described above, thin films made of aluminum or titanium were used as the conductive thin film 25, but conductive films other than metals (such as organic conductive films) may be used if they are appropriate from the standpoint of the Food Sanitation Law, etc. • In the above embodiment, an example was shown in which seven strip-shaped conductive thin films 25 are arranged at approximately equal intervals, but the arrangement of the conductive thin films 25 can be changed as appropriate. For example, as shown in Figure 5A, a configuration may be adopted in which a single conductive thin film 25 is provided at a position equidistant from each of the first planar electrode 21A and the second planar electrode 21B. Alternatively, as shown in Figure 5B, a configuration may be adopted in which one conductive thin film 25 is provided near the first planar electrode 21A and one near the second planar electrode 21B. Furthermore, as shown in Figure 5C, a configuration may be adopted in which the conductive thin films 25 are provided at three locations: the center between the first planar electrode 21A and the second planar electrode 21B, near the first planar electrode 21A, and near the second planar electrode 21B. The width of the conductive thin film 25 can also be changed as appropriate, and if multiple conductive thin films 25 are arranged, their widths may be different. [Examples]

[0041] <Electrified heating test> A cylindrical container made of polypropylene was filled with a cylindrical object to be heated, with a diameter of 80 mm and a height of 170 mm. This object was then heated by applying an electric current while sandwiched between a first planar electrode 21A and a second planar electrode 21B. The first and second planar electrodes 21A and 21B were stainless steel electrodes. The object to be heated was dried gluten diluted with 50 mmol / L salt water to a concentration of 50 wt%. The electric current heating conditions were 130 V and a frequency of 60 Hz. (Example 1) In Example 1, as shown in Figure 6A, seven aluminum foil tapes (3M AL-50BT) with a width of 10 mm and a thickness of 0.08 mm were used as the conductive thin film 25. The distance between the first planar electrode 21A and the uppermost conductive thin film 25, and the distance between the second planar electrode 21B and the lowermost conductive thin film 25, were both 15 mm. Each conductive thin film 25 was arranged at equal intervals of 10 mm. (Example 2) In Example 2, as shown in Figure 6B, five aluminum foil tapes (3M aluminum foil conductive tape (AL-50BT)) with a width of 10 mm and a thickness of 0.08 mm were used as the conductive thin film 25. The distance between the first planar electrode 21A and the uppermost conductive thin film 25, and the distance between the second planar electrode 21B and the lowermost conductive thin film 25, were both 15 mm. One conductive thin film 25 was placed in the center (75 mm point) at an equidistant distance from the first planar electrode 21A and the second planar electrode 21B, and one conductive thin film 25 was placed above and below it at 10 mm intervals. (Example 3) In Example 3, as shown in Figure 6C, four aluminum foil tapes (3M aluminum foil conductive tape (AL-50BT)) with a width of 10 mm and a thickness of 0.08 mm were used as the conductive thin film 25. The distance between the first planar electrode 21A and the uppermost conductive thin film 25 was 15 mm, and one conductive thin film 25 was placed below it with a gap of 10 mm. The distance between the second planar electrode 21B and the lowermost conductive thin film 25 was 15 mm, and one conductive thin film 25 was placed above it with a gap of 10 mm. (Comparative Example 1) In Comparative Example 1, aluminum foil tape was not used.

[0042] The object to be heated was heated by electric current until its core temperature (detected at position P1 in the figure) reached 130°C. Table 1 shows the detected side temperature (detected at position P2 in the figure) when the core temperature of the object to be heated reached 130°C in each example and comparative example. An ungrounded sheathed thermocouple (manufactured by Toho Electronics Co., Ltd.: S1K10X150-A2X5C) was used for the measurement. [Table 1]

[0043] In Comparative Example 1, where no aluminum foil tape was placed, the temperature difference between the center temperature and the side temperature was 55°C. In contrast, in Example 1, the temperature difference was 2°C, in Example 2, it was 10°C, and in Example 3, it was 6°C, confirming that the temperature difference was suppressed compared to Comparative Example 1.

[0044] The same electrical heating test was performed using a conductive thin film 25 made of titanium. (Example 4) In Example 4, as shown in Figure 7A, four titanium plates (XMRISE titanium plate sheet foil) with a width of 10 mm and a thickness of 0.1 mm were used as the conductive thin film 25. One conductive thin film 25 was placed 10 mm from the first planar electrode 21A, and another conductive thin film 25 was placed with a gap of 10 mm between them. Similarly, on the lower side, one conductive thin film 25 was placed 10 mm from the second planar electrode 21B, and another conductive thin film 25 was placed with a gap of 10 mm between them.

[0045] The object to be heated was heated by electric current until its core temperature (detected at position P1 in the figure) reached 130°C. Table 2 shows the detected side temperature (detected at position P2 in the figure) when the core temperature of the object to be heated reached 130°C in each example and comparative example. An ungrounded sheathed thermocouple (manufactured by Toho Electronics Co., Ltd.: S1K10X150-A2X5C) was used for the measurement. [Table 2]

[0046] In Example 4, which used a titanium plate, the temperature difference was 6°C, confirming that the temperature difference was suppressed, similar to Examples 1-4 which used aluminum foil tape. [Industrial applicability]

[0047] As an example of the dried protein-containing materials mentioned above, alternative meat materials can be cited. In recent years, with the increase in the world population and the rise in demand for protein due to increased meat consumption, the development of materials made from agricultural protein as meat substitutes has become more active.

[0048] These alternative meat materials often use defatted soybeans as a raw material. Generally, defatted soybeans lose processing properties such as water solubility and binding properties due to heat treatment and processing with organic solvents during the defatting process. Therefore, materials that have lost their processing properties are converted into expanded and dried materials using extrusion processing, and these materials that are available on the market can be rehydrated, softened, and flavored.

[0049] However, alternative meat materials still suffer from problems such as inferior texture compared to meat, difficulty in manufacturing them in various sizes (especially large shapes), and the time and effort required for cooking and processing. By manufacturing food 50 using processing equipment 1, such alternative meat materials can be transformed into food 50 with a unified moist texture.

[0050] The dried protein-containing material may be a substitute meat material, or other dried foods such as jerky or dried squid. These can also be transformed into food 50 with an integrated moist texture using the food manufacturing method of food 50 using processing device 1. [Explanation of Symbols]

[0051] 1: Processing equipment 2: Heating unit 3: Cooling unit 10: Interior space 10A: Heating space 10B: Cooling space 20: First cylindrical body 20A: Outer cover 20B: Vacuum hole 21A: First planar electrode 21B: Second planar electrode 22A: Sealing material 22B: Sealing material 25: Conductive thin film 30: Second cylindrical body 31: Jacket section 40A: First temperature sensor 40B: Second temperature sensor 50:Food

Claims

1. A heating unit comprising a cylindrical body, a first planar electrode, a second planar electrode, and a conductive thin film, The cylindrical body is configured to be filled with conductive food, The first planar electrode and the second planar electrode are configured to be positioned on both sides of the food filled in the cylindrical body so as to seal the food, The conductive thin film is provided in a strip shape along the circumferential direction at a position between the first planar electrode and the second planar electrode on the inner circumferential surface of the cylindrical body, A heating unit configured to heat food by supplying an electric current to the food from the first planar electrode and the second planar electrode.

2. A heating unit according to claim 1, The conductive thin film is a heating unit in which the longitudinal width of the cylindrical body is 20 to 70% of the distance between the first planar electrode and the second planar electrode.

3. A heating unit according to claim 1 or claim 2, The conductive thin film is arranged in multiple locations along the longitudinal direction of the cylindrical body, forming a heating unit.

4. A heating unit according to claim 1 or claim 2, A heating unit wherein the first planar electrode and the second planar electrode are configured to be movable along the longitudinal direction of the cylindrical body while sliding on the inner circumferential surface of the cylindrical body, and are configured to pass through the position where the conductive thin film is arranged.

5. A method for producing food using the heating unit described in claim 1 or claim 2, comprising a clamping step and a heating step, In the clamping step, a conductive food made of a protein-containing material is placed in the heating space inside the cylindrical body, and the food is clamped between the first planar electrode and the second planar electrode. In the heating step, the first planar electrode and the second planar electrode move to positions on both sides of the conductive thin film in the longitudinal direction of the cylindrical body, respectively, while the food is still clamped, and the food clamped in the clamping step is heated by applying an electric current to a predetermined heating temperature.

6. A food product manufactured by the food manufacturing method described in claim 5.

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