JP5288286B2 - Food thawing / refrigerated storage equipment - Google Patents

Description

The present invention relates to a thawing-refrigeration method and apparatus for food, and more particularly, to a frozen food thawed conserved or non-frozen perishable foods concerning that equipment be refrigerated using an electric field.

  Conventionally, refrigeration and frozen storage are known as methods for preserving fresh food. However, there is a problem that the quality of food ingredients such as freshness, appearance, taste, etc. is reduced due to transpiration (drying) of water in refrigerated storage and cell destruction due to freezing of moisture in food or low temperature denaturation of protein in frozen storage. .

  On the other hand, for frozen storage, as shown in Patent Document 1, an ice is formed by repeating an overcooling step and a cooling step for stopping the application of the electric field by forming an electric field in the food storage space in the freezer. A method for preventing cell destruction by preventing an increase in the size of crystal grains of water (free water) is known.

  As for thawing of frozen food and storage after thawing, as shown in Patent Document 2, there is known a method of charging food with weak energy of relatively low voltage of 500 to 1500 V in a freezer.

JP 2007-259709 A Japanese Patent No. 2696310

  However, the technique of Patent Document 1 is a method and apparatus for freezing food using supercooling, and is not related to thawing or storage after thawing, and also to the moisture content, weight, etc. of ingredients. Accordingly, it is necessary to set time, voltage, and frequency value in each process, and the control is complicated.

  Moreover, since the method and apparatus of patent document 2 make the goods shelf and container in a freezer into an electroconductive material, and electrically charge foodstuff itself, when this is applied to a large-sized freezer and a refrigerator, the food used as an electrode Not only is it necessary to increase the size of the shelves and containers and the freezer itself, or it is necessary to prepare a large number of freezers, but this is disadvantageous in that power loss is also large.

In view of the problems in the conventional storage method, the object of the present invention is to defrost / refrigerate food that can maintain stable quality even for several days without requiring skill level such as simple constitution and identification of ingredients. It is to provide a SonSo location.

To this end, the present invention includes a mounting member 2 can be mounted in a state in which electrically insulates the save object W to the first, provided in an electrically insulated state and the placing placement member 2 And a voltage application electrode 5 that is electrically insulated from the storage object W across the storage object W and faces the ground electrode 3 in the vertical direction. A storage device for use in a thawing / refrigeration storage method for forming an electric field by applying a high-frequency AC voltage between the storage object W and the storage object W can be mounted on the upper surface, A pallet 2 that is electrically insulated, a ground electrode 3 that is provided on the bottom surface of the pallet 2 and connected to the ground , and a storage object W sandwiching the storage object W mounted on the top surface of the pallet 2 Electrically insulated and provided to face the ground electrode 3 in the vertical direction; A voltage application electrode 5 connected to the collector 4, the voltage applying electrode 5 was suspended with an electrically insulating state, the pallet 2 of the upper electrode support with a moving configurable to a position opposite to the member 6 It is characterized by comprising.

Second, high voltage of the previous SL-applying electrode is characterized in that it is set to 500～1500V.

Third, before Symbol electrode support member 6, characterized in that it is capable of adjusting the opposing distance with respect to the upper surface of the storage object W.

Fourth, prior Symbol electrode support member 6, characterized in that the frame body provided with wheels 7 to the bottom are used.

Fifth, pre-Symbol pallet 2 and the electrode support member 6, characterized in that it is can be installed by more juxtaposed cold space.

Sixth, the prior SL cold space, cold warehouse 100 other large facilities is of interest, the electrode supporting member 6 in-holding cold warehouse 100 is a storage object W mounted by the hoist 101 to the pallet 2 The positional relationship is controlled .

  According to the present invention, the object to be stored is arranged in an electric field formed between the voltage application electrode and the ground electrode, being electrically insulated from both electrodes, thereby increasing the transmission speed to the target temperature. As a result, the target temperature can be reached quickly. As a result, cell destruction of food materials and low temperature denaturation of proteins can be prevented, and transpiration of water can be suppressed to prevent deterioration of freshness and other qualities.

  In addition, since a high-frequency AC voltage is applied to the voltage application electrode, it is possible to prevent freezing due to active movement of water molecules in the storage object. Thereby, even in the case of fruits and vegetables, the destruction of cells due to freezing can be prevented by maintaining a storage temperature suitable for this. In addition, in fish meat, drip and the like can be prevented by maintaining the storage temperature.

In particular, these actions can constitute a high potential electric field between the electrodes by providing an insulating structure between the storage object and the mounting member and between the mounting member and the ground electrode. It will be even more certain.
In addition, since the electrodes are provided separately from the food shelves and refrigerators, even if the freezing and refrigeration equipment is enlarged, the number of electrodes and pallets can be increased without increasing the size of the food shelves and containers. It is advantageous in terms of equipment cost and energy cost.

It is a figure for demonstrating the principle structure of the preservation | save apparatus used for the thawing | freezing / refrigeration preservation | save method by this invention. It is a circuit diagram for illustrating a configuration of a power supply device used in a save device shown in FIG. It is a graph which shows the generation | occurrence | production state of the frequency of AC voltage applied by the electric power feeder shown in FIG. 2, a temperature change, and supercooling. It is a figure which shows the simulation result regarding the conditions for experimenting the electric field strength with respect to a preservation | save object, and an electric field strength. It is a figure which shows the example of application of the preservation | save apparatus shown in FIG. It is a figure for demonstrating the other application example of the preservation | save apparatus shown in FIG. It is a figure which shows the example which applied the preservation | save apparatus shown in FIG. 1 to the cold storage warehouse. It is a figure which shows the result of the experiment example by the preservation | save method using the preservation | save apparatus by this invention by the water content change of a melon. It is a figure which shows the difference in the ripening degree of a melon in the result shown in FIG. It is a figure which shows the result of the experiment example by the preservation | save method using the preservation | save apparatus by this invention by the moisture content change of a strawberry. It is a figure which shows the result of the experiment example by the preservation | save method using the preservation | save apparatus by this invention by the water content change of taro.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a principle structure of a storage device applied to a thawing / refrigerated storage method according to the present invention.

  In the figure, the storage device 1 is equipped with a pallet 2 on which a storage object W targeted for fresh food such as fruits and vegetables and fish meat can be mounted on the upper surface, and is electrically insulated from the storage object W. The ground-side electrode (ground electrode) 3 provided on the bottom surface of the pallet 2 and connected to the ground portion and the storage object W mounted on the top surface of the pallet 2 are opposed to the ground electrode 3 in the vertical direction. The non-grounded electrode (voltage application electrode) 5 connected to the power feeding device 4 and the voltage application electrode 5 are suspended and supported in an electrically insulated state, and moved to a position facing the upper surface of the pallet 2. And an electrode support member 6 having a possible configuration. Details of each member will be described below.

  The pallet 2 is a wooden member that is usually used for transportation with a flat plate facing up and down and a space between which a fork of a forklift is inserted. A ground electrode 3 made of a conductive plate is integrally formed on the bottom surface of the pallet 2. It has become.

  The ground electrode 3 is connected between the ground electrode 3A using a wire mesh or the like and the ground, and the portion other than the range where the ground electrode 3A is grounded is insulated from the ground by the insulator 3B.

  The storage object W mounted on the top surface of the pallet 2 is mounted between the top surface of the pallet 2 via an insulator W1 and electrically between the ground electrode 3 positioned on the bottom surface of the pallet 2. Insulated.

  The voltage application electrode 5 facing the ground electrode 3 across the storage object W, in other words, above the pallet 2 in the vertical direction, is supported on a movable frame constituting the electrode support member 6. A conductive plate member is used that is suspended and supported by a chain 6C or the like while being insulated by a plate 6A by an insulator 6B.

The electrode support member 6 is a frame having support columns 6A that are fixed to the upper surface and positioned in the vicinity of the four corners of the pallet 2. The support member 6 is provided with rolling members 7 such as casters and moves. It can be done.
Since the electrode supporting member 6 can move, the electrode supporting member 6 can be moved to the position where the pallet 2 is placed and the voltage applying electrode 5 can be opposed to the ground electrode 3.

On the other hand, the structure shown in FIG.
In FIG. 2, an AC power supply 4A2 is connected to the primary coil 4A1 of the transformer 4A, and the secondary coil 4A3 side of the transformer 4A and the primary coil 4A1 are grounded via a short circuit 4B.

  The secondary coil 4A3 side is connected to the primary coil 4C1 of the step-up transformer 4C, and the voltage application electrode 5 shown in FIG. 1 is connected to the secondary coil 4C3 via the resistor 4D via the iron core 4C2. ing. In addition, the code | symbol 4E is the insulation sealing part provided in the one phase of the secondary coil 4C3 of the pressure | voltage rise transformer 4C.

This configuration is a configuration partially described in Japanese Patent No. 2696310, which is the prior application of the present applicant, and the voltage application electrode 5 is boosted to 500 to 1500 V by the boosting transformer 4C. The high voltage is applied to the voltage application electrode 5 through the conductive wire 4F to form a high-voltage alternating (alternating) electric field with the ground electrode 3.
Thereby, the preservation | save object W is located in a high electric potential electric field, and is under the influence of an alternating electric field. For example, even if it exists in a temperature range of -5 degreeC-8 degreeC, a water | moisture content does not freeze and evaporates ( (Drying) can be suppressed.

  In particular, in the present embodiment, an insulating structure is provided between the storage object W and the pallet 2 and between the pallet 2 and the ground electrode 3, so that the storage object W is in a high potential electrostatic field between the electrodes. Can be exposed.

By the way, in the present invention, it is necessary to set a desired frequency in addition to the voltage condition. FIG. 3 shows that water (tap water is put into a 280 ml PET bottle under a cooling atmosphere temperature of −6 to −10 ° C. ) The core temperature change when cooling (weight 250 g, moisture content 99%) is simulated for the case where there is no electric field formation and the case where the frequency f is 100 Hz, 500 Hz and 1000 Hz.
As a result, in this example, in the case of 1000 Hz, it is clear that the temperature change (descent) speed is high, the supercooling temperature is the lowest, and that there is a low temperature peak of supercooling around 65 minutes after the start of cooling. It is.
In other words, the frequency of the applied voltage is a parameter that affects the electric field strength formed between the electrodes, and the electric field strength is considered to greatly influence the rate of temperature change, the peak of supercooling, and the like.

4 (A) and 4 (B) show an apparatus in the case where an electric field is formed on boxed melons stacked on the pallet 2 in seven stages, the arrangement state of the objects, the voltage of each stage, and It is a schematic diagram which shows the simulation value of electric field strength.
In the above simulation, the electric field strength when the food material is charged with a high potential is assumed to be the dielectric constant ε of the food material using the voltage measurement recording (value) and electric field strength simulation software (ε = 50).
In the above data, there is a difference between the simulation value and the actual measurement value. This is because there is no leakage current etc. in the simulation value. by. However, according to the long-term storage results described later, it has been found that if the voltage value is 100 V or higher, the quality storage such as freshness can be stored in each stage of (1) to (7).
In addition to the above, when compared with the result of the simulation with only one stack, there is also a difference in the voltage value in the melon, and the cardboard boxes containing the melon are more easily charged in the seven-stack stack. The non-grounded electrode 5 is preferably as close to the target as possible.

The storage device 1 having the principle structure shown in FIG. 1 is not limited to providing only one pallet 2, and for example, as shown in FIG. 5, the pallets 2 can be mounted on a plurality of shelves. In this configuration, the ground electrode 3 is provided on the pallet 2 side in the space in which each pallet 2 is arranged, and the voltage application electrode 5 is provided at a position facing the ground electrode 3. In FIG. 5B, some members including the wire mesh 3A shown in FIG. 5A are omitted.
In this case, the ground electrodes 3 and the voltage application electrodes 5 are connected in common by a ground circuit 30 and a power supply circuit 40.

  On the other hand, in order to efficiently form the electric field strength between the electrodes, for example, as shown in FIG. 6, a lifting mechanism 10 that can lift and separate the voltage application electrode 5 from the storage object W is used. be able to.

  The lifting mechanism 10 has a pinion gear (not shown) having an output shaft of an electric motor 10A attached to a voltage application electrode (indicated by reference numeral 5 used in FIG. 1 for convenience) as an electrode support member (for convenience in FIG. 1). The structure which can be moved up and down by meshing with the rack provided in the support | pillar part of the (symbol 6 used in No. 6) is used.

  The electric motor 10A can be moved up and down in accordance with the operation of a lift switch provided on an operation panel (not shown), and the position on the upper surface of the storage object W can be determined. Although there is no exact regulation regarding the distance between the upper surface of the storage object W and the voltage application electrode 5, the most efficient position for forming the electric field is determined in advance by experiments and the like. It is desirable to set a position where the electric field intensity can be set to obtain a position where the transpiration of water can be efficiently suppressed. Note that part of the members illustrated in FIG. 6A is omitted in FIG.

Moreover, since the voltage application electrode 5 is provided for one pallet 2, it can be applied to a place where a plurality of pallets 2 are juxtaposed.
FIG. 7 is a diagram showing the configuration in this case, and the example shown in FIG. 7 shows a case where the pallet 2 is applied to the cold storage warehouse 100.

In FIG. 7, a refrigeration device (not shown) is provided inside the cold storage warehouse 100 so that the inside of the warehouse can be maintained at a constant refrigeration temperature.
A plurality of electric hoists 101 are provided on the ceiling in the warehouse, and the pallet 2 can be positioned below the electric hoists 101.

A voltage application electrode 5 is suspended and supported on the electric hoist 101, so that the facing distance from the storage object W mounted on the pallet 2 can be positioned at a desired distance.
The pallet 2 is transported and positioned by the forklift 102 to a position facing the voltage application electrode 5.

  The pallet 2 uses the configuration shown in FIG. 1, and can form an electric field with the voltage application electrode 5 and the ground electrode 3 provided on the bottom surface of the cold storage warehouse 100. . Although not shown, an insulator is disposed between the storage object W and the pallet 2.

  Since the present invention is configured as described above, when the storage object W is mounted between the voltage application electrode 5 and the ground electrode 3 while being insulated from the pallet 2, the voltage application electrode 5 Then, a high frequency voltage of 100 to 1000 Hz is applied from the AC power source 4 at 500 to 1500V.

  When one of the electrodes is grounded, an electric field due to a potential difference is formed, and the inside of the storage object W that is insulated in the electric field is charged to cause polarization inside. As a result, conditions sufficient to align and evaporate the charges inside the storage object W are regulated.

  On the other hand, the application of high-frequency alternating voltage suppresses the propagation of bacteria due to the clustering of electrons.

  The inventors of the present invention experimented on the storage state of the storage object W in the cold storage warehouse using the apparatus and method shown in FIGS. 1 and 4 and obtained the following results.

(Experimental example 1)
In Experimental Example 1, for melon, five pieces are packed in a plurality of cardboard boxes as shown in FIG. 4 (see FIG. 9A), and the cardboard boxes are stacked on the pallet 2 in a state of being stacked in seven stages. It was mounted and the water content change of the melon and the aging state inside the melon were observed under the electric field strength shown in FIG.
For melons with charging (things using electric field formation), 5 pieces are accommodated in 7 corrugated cardboard boxes, respectively, and for those without charging (things without electric field formation), 5 melons are also packed. A box was prepared, and the average value of the measured values was obtained twice.

  FIG. 8 shows the result of obtaining the water content from the degree of weight loss of melon, and FIG. 9 shows the case where an electric field is formed from the state before the experiment shown in (A) (FIG. 9 (B) left), The aging change state inside the melon is compared with the case where an electric field is not used (right of FIG. 9B). As a result, in terms of weight change, the average weight loss of the average weight of 1247 g / piece at the start was 21.86 g / piece (1.76%) when charged and 27.00 g / piece when charged (2) There was a significant difference between the two.

  Thus, in FIGS. 8 and 9, regarding the water content, it can be seen that the decrease in the water content is less when the electric field is formed than when the object to be stored is not charged without forming the electric field. Regarding the ripened state, it was confirmed that the aging change (decrease in freshness) progressed more clearly in the case where the electric field was not formed than in the case where the electric field was formed.

(Experimental example 2)
FIG. 10 shows a space of about 400 mm between upper and lower electrodes made of a metal wire of 5φ divided into six by arranging five lattices in the longitudinal direction in a 450 × 590 (mm) rectangular frame for strawberries. This is the result of conducting experiments in February and March 2007 under the same conditions as in the experimental examples shown in FIGS.
As is apparent from the results of this experiment, it can be seen that in this example, even when the other storage temperature conditions are the same, the transpiration of water is suppressed and the water content is prevented from decreasing.

(Experimental example 3)
FIG. 11 shows the result of an experiment conducted in 2007 using the same apparatus and electric field formation as in Example 2 for taro.
As is clear from the results of this experiment, in this example, it was found that transpiration of water was suppressed even in the same conditions as other storage temperature conditions, and a decrease in freshness due to a decrease in water content was prevented. .

  In the above embodiments, the high-frequency voltage applied to the voltage application electrode is a uniform value, and can be set only by selecting the type of the storage object. In particular, by defining the frequency, work such as weighing for each object to be stored and determination of moisture content becomes unnecessary, and an appropriate storage state can be set without requiring skill of work.

  In the above experiments, at least when melon, strawberry, and taro were stored refrigerated in an alternating electric field at a high voltage, a significant difference was observed in the decrease in the water content that was considered to be directly related to the freshness of the food. Although the exact mechanism of transpiration reduction is not clear, it is clear that the electric field suppresses the transpiration of food by some action. Moreover, it can be easily assumed that these actions are common to all foods containing a large amount of moisture (especially free water).

DESCRIPTION OF SYMBOLS 1 Storage device 2 Palette 3 Ground electrode 4 Power supply device 5 Voltage application electrode 6 Electrode support member 7 Caster 10 Lifting mechanism 100 Cold storage 101 Electric hoist

Claims (6)

A mounting member (2) that can be mounted in a state in which the object to be stored (W) is electrically insulated; a ground electrode (3) that is provided in an electrically insulated state from the mounting member (2); A voltage application electrode (5) that is electrically insulated from the storage object (W) across the storage object (W) and is opposed to the ground electrode (3) in the vertical direction is provided. ), (5) is a storage device used in a thawing / refrigerated storage method for forming an electric field by applying a high-frequency alternating voltage between ,
A pallet (2) on which an object to be stored (W) can be mounted on the upper surface and electrically insulated from the object to be stored (W);
A ground electrode (3) provided on the bottom surface of the pallet (2) and connected to the ground;
The storage object (W) mounted on the upper surface of the pallet (2) is sandwiched between the storage object (W) and is electrically opposed to the ground electrode (3) in the vertical direction. A voltage application electrode (5) connected to the device (4);
An electrode support member (6) having a configuration in which the voltage application electrode (5) is suspended and supported in an electrically insulated state and is movable to a position facing the upper surface of the pallet (2). Defrost / refrigerate storage device. Thawed and refrigerated storage device of claim 1, the high voltage at the previous SL application electrode, characterized in that it is set to 500～1500V. Before Symbol electrode support member (6) is thawed and refrigerated storage device according to claim 1 or 2, characterized in that it is possible to adjust the facing distance with respect to the upper surface of the storage object (W). Before Symbol electrode support member (6) is thawed and refrigerated storage device according to any one of claims 1 to 3, characterized in that the frame body provided with a wheel (7) in the bottom is used. Before SL pallet (2) and the electrode support member (6) is thawed and refrigerated storage device according to any one of claims 1 to 4, characterized in that it is installed by a plurality juxtaposed cold space. The pre SL cold space, cold warehouse (100) other large facilities is of interest, the electrode support member in-holding cold warehouse (100) (6) is mounted on the pallet (2) by the hoist (101) The thawing / refrigeration storage device according to claim 5, wherein the positional relationship with the storage object (W) is controlled.