JP2008131863A - Method and apparatus for retaining quality of food and drug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus rapidly deadening contaminating harmful insects and their eggs or germs at a normal temperature and a normal pressure without deteriorating the quality of food and drugs. <P>SOLUTION: This apparatus comprises using a high frequency vibration machine which supplies high frequency power having frequency of 1-300 MHz, and an electrode which can apply high frequency power of strong electric field strength to an object to be treated by having a structure of arranging at least one pair of a high pressure electrode and an earth electrode at intervals without putting an object to be treated between, or avoiding the electrodes to face each other even putting an object to be treated between. Thus, the apparatus can deaden harmful insects and their eggs or germs contaminating food and drugs in an extremely short time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a food and pharmaceutical quality maintaining method and apparatus for killing insects, insect eggs and bacteria mixed in foods and pharmaceuticals by high-frequency power in a short time.

Pests or bacteria that grow and propagate in food products, spices and other agricultural products, and medicines such as Chinese medicines are generated in large quantities if environmental conditions such as storage temperature are satisfied, which lowers the product value or causes defective products. These pests are mixed during harvesting or distribution of agricultural products or pharmaceutical raw materials, and grow or propagate. It is indispensable to kill these pests and bacteria, but the means are limited because the target exists in food and medicine. Known insecticidal and sterilizing methods in foods and pharmaceuticals include a method using heating, a method using chemicals, a method using light and radiation, and a method using low temperature.

The conventional methods have the following problems.

In the method using heating, it is necessary to keep the temperature of the entire object to be treated, in which the pests and the like are mixed, at least 70 ° C. or higher in order to increase the temperature of the target pests and eggs. When heated for a long time in order to enhance the killing effect, it is known that the nutritional value decreases, the medicinal effect changes, the color changes, the flavor deteriorates, etc. in foods and pharmaceuticals.

In the chemical method, fumigation treatment with a chemical agent such as methyl bromide is generally performed. In addition, sterilization and insecticidal treatment with gas such as ethylene oxide is also performed. However, problems such as the risk of scattering and residual drugs and the effects on the human body are pointed out, and it is expected that it will become difficult to use in the future.

Ultraviolet rays having sterilizing power are also effective as an insecticidal method, but the insecticidal and sterilizing effect of the shadowed part cannot be obtained with light rays, and the eggs existing at the center of the object to be treated cannot be killed. In addition, there are dangers of handling and by-products in the method of extermination by radiation, and its use in Japan is limited.

A method of performing freezing / freezing processing has also been proposed, but the processing time is long and the required energy is large. In addition, some insect pests have cold resistance and may not be effective. There is almost no effect on bacteria.

A method using high-frequency heating has been proposed as an insecticidal and sterilizing method for foods and pharmaceuticals by heating. Heating by high frequency is P = ωε ′ where P is the heat generation amount per unit volume of the object to be heated, ω is the angular velocity, ε ′ is the dielectric constant, ε ″ is the dielectric loss factor, tan δ is the dielectric loss tangent, and E is the electric field strength. tanδE ²
= Ωε ”E ²
Can be expressed as On the other hand, in order to prevent thermal denaturation that occurs during the killing and sterilization of foods and pharmaceuticals, it is necessary to quickly raise the temperature of the object to be heated and to quickly lower the temperature after the treatment. When placing an object to be processed in a high frequency electric field, it is necessary that the dielectric loss factor and the electric field strength be large in order to increase the amount of heat generation. It is also effective that the frequency is high, but it is reported that the pest can be selectively heated because the dielectric loss rate of the pest is larger than that of the grain particularly in the frequency range of 10 MHz to 70 MHz.
Japanese Journal of Agricultural Machinery 49 (5): 443-450, 1987

As an electrode structure used in a conventional high-frequency heating apparatus, an apparatus having a structure in which a workpiece is sandwiched between upper and lower electrodes has been proposed. When the electrode and the object to be processed are not in direct contact, the above-described equation relating to heat generation is established. In the structure in which the object to be processed is sandwiched between the opposing electrode plates, the high-voltage side electrode and the ground-side electrode are opposed to each other over a wide area, so that the inter-electrode impedance for high frequency is low. Assuming that the power supplied from the high-frequency oscillator is constant, if the impedance between the electrodes as the load is low, a large amount of high-frequency current flows between the electrodes, but the voltage between the electrodes is relatively low. Since the calorific value is proportional to the square of the electric field intensity at the place where the object to be heated exists, it cannot be heated efficiently if the voltage between the electrodes is low. Increasing the distance between the electrodes while keeping the supplied power constant increases the impedance between the electrodes and increases the voltage between the electrodes, but the distance between the electrodes and the object to be heated increases, resulting in the electric field strength at the place where the object to be processed exists. However, the heat generation amount cannot be increased. When the object to be processed is densely packed between the electrodes facing each other, since the object to be processed is a dielectric, the impedance is lowered, and the voltage between the electrodes cannot be increased. For these reasons, it is difficult to heat foods and pharmaceuticals in a short time using electrodes that have been used in the past, and it is necessary to lengthen the heating time in order to obtain a sufficient killing effect. Has been difficult to put to practical use because it has deteriorated due to heat denaturation and the processing speed of the apparatus cannot be increased.
JP 2003-259727 A

The present invention is an apparatus that applies high-frequency power to foods and pharmaceuticals, and a high-frequency oscillator that generates high-frequency power, and a pest or a pest egg or bacterium in an object to be processed that exists near or passes through an electrode. And an electrode for applying high-frequency power having a high electric field strength. In the first aspect of the present invention, one or more pairs of the high-voltage side electrode and the ground-side electrode are alternately arranged on only one side without sandwiching the workpiece in the vicinity of the workpiece to be passed. Is done. In the invention of claim 2, the structure of the electrode for applying the high-frequency power is such that the high-voltage side electrode is spaced on one side of the workpiece and the ground-side electrode is spaced on the opposite side in the vicinity of the workpiece to be passed. It is characterized in that one or more pairs are arranged in a space and are not facing each other. In any of the electrodes of the present invention, the electrode area on the surface where the high-voltage side electrode and the ground-side electrode face each other is much smaller than the conventional opposing electrodes, so the impedance to the high frequency between the electrodes is high, and the high-frequency current that does not contribute to heating is small . Therefore, the voltage between the electrodes can be increased even with the output of the same oscillator. By placing the high-frequency side electrode and the ground-side electrode close to the limit where no discharge occurs, and bringing the electrodes and the object to be processed close to the limit where they do not contact, a large electric field strength can be given to the object to be processed. The place where the electric field strength is high is a portion between the adjacent high-voltage side electrode and the ground-side electrode, and an object to be processed adjacent thereto. Particularly, the thickness of the workpiece to be heated rapidly is about several millimeters, and reaches a temperature at which the pests and their eggs are killed in a few seconds. Since the object to be heated spreads thinly, when it is away from the electrode, it efficiently dissipates heat by radiation and heat conduction, and the temperature rapidly decreases. Therefore, foods and pharmaceuticals are rarely subjected to heat denaturation, and pests and bacteria are killed in a short time.

In an apparatus for heat sterilization or heat insecticidal treatment, it is indispensable to hold at a certain temperature or more for a certain time. When the method and apparatus according to the present invention is used, the place where the electric field strength is high is limited to the portion between the adjacent high-voltage side electrode and the ground-side electrode and the portion where the object to be processed is present. No uniform high frequency power is applied to the heated object over time. That is, as the object to be heated moves in the vicinity of the electrode, strong high-frequency power is intermittently applied only several times as many times as the number of electrodes. The temperature of the object to be processed that moves in the vicinity of the electrode rises at a stretch in places where high-frequency power is applied, and decreases due to heat dissipation in places where high-frequency power is not applied. Therefore, the temperature of the object to be processed does not continue to rise excessively while passing through the inside of the apparatus, quality deterioration due to the temperature of the object to be processed is suppressed, and it can be heated to a temperature higher than that required for sterilization or insecticide. Become.

In the electrode according to the second aspect of the invention, the high-voltage side electrode and the ground-side electrode are on opposite sides of the object to be processed, and a portion having a large electric field strength crosses the object to be processed. Even when the thickness is large or the particle size is large, the whole can be heat-treated.

By treating foods and pharmaceuticals using the method and apparatus according to the present invention, it becomes possible to heat-treat pests, pest eggs or bacteria in the processed material in a very short time, The adverse effect of temperature on quality can be suppressed, and quality can be maintained for a long time while maintaining flavor and safety.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment according to a method and an apparatus for maintaining quality of food and medicine according to the present invention will be described with reference to the drawings. 1 to 7 show an embodiment of the invention according to the present invention.

FIG. 1 is a configuration diagram of a quality maintenance device. The powder or fine granular material 7 supplied to the supply hopper 4 is supplied onto the conveyor 6, and after passing through the vicinity of the high-frequency electrode 2 after being limited to a certain thickness or number by the thickness adjuster 3. The high frequency electrode 2 is supplied with high frequency power generated by the high frequency oscillator 1 through a conductor 10 having a coaxial structure. The high-frequency oscillator 1 can oscillate a frequency suitable for insecticidal and sterilizing between 1 MHz and 300 MHz. The object to be treated is moved in the vicinity of the high-frequency electrode 2 by taking a sufficient time necessary for killing the pests or the eggs of the pests or killing the harmful bacteria, and then collected in the collection hopper 5 after the treatment is completed. Is done. The conveyor 7 may be horizontal or inclined. The position where the electrodes are arranged may be on the lower side of the conveyor.

FIG. 2 is an explanatory view of a high-frequency electrode according to the apparatus of claim 1, and FIG. 6 is an enlarged view showing an object to be processed and pests therein. The ground-side electrode 7 and the high-voltage side electrode 8 have a structure in which they are alternately arranged on the same plane at intervals. The distance between the ground-side electrode 7 and the high-voltage side electrode 8 can be narrowed regardless of the size of the object 9 to be processed, and the portion with high power density is concentrated in the vicinity between the electrodes, so that the electric field strength can be increased. It becomes possible to effectively kill the pests 12, the eggs of the pests, or the bacteria present in the vicinity.

3 and 4 are structural views of the high-frequency electrode according to the apparatus of claim 1. The material of the electrode is a conductor such as copper, aluminum, or brass, and the shape is flat or cylindrical, and other similar shapes may be used.

FIG. 5 is an explanatory view of a high-frequency electrode according to the apparatus of claim 2. The ground side electrode 7 and the high voltage side electrode 8 are arranged in a plover shape with the workpiece 9 interposed therebetween. This is effective when the thickness of the workpiece is large.

The conveyor 6 of the apparatus used in the present invention does not necessarily have the conveyor 6, but the object 9 is freely dropped by gravity on a radio wave transmitting plate having an inclination, and FIG. 2 or FIG. If the high-frequency electrode shown by 5 is arranged, high-frequency power is applied while the object 9 is falling, and the object to be processed such as food and medicine is killed and sterilized.

FIG. 7 schematically shows a difference in temperature change of an object to be processed between the case where the conventional heat treatment is performed and the case where the heat treatment according to the present method is performed. In Example 1 of the conventional method, since the rate of temperature increase is slow, it takes time to reach the temperature range necessary for insecticidal or sterilization, and the temperature rise continues and reaches the heat denaturing range. Further, when the applied power is reduced while avoiding heat denaturation as in Example 2 of the conventional method, the heating time in the temperature range necessary for insecticidal or sterilizing is insufficient. On the other hand, in this method, as the object to be heated moves in the vicinity of the electrode, strong high frequency power is intermittently applied, and the temperature of the object to be processed rises rapidly at a place where the high frequency power is applied, and decreases by heat dissipation at a place where the object is not applied. Repeat that. Accordingly, the object to be processed quickly reaches a desired temperature and does not continue to rise excessively while passing through the inside of the apparatus, and quality deterioration due to the temperature of the object to be processed is suppressed.

The result of processing brown rice with the quality maintaining apparatus shown in FIG. 1 is shown below.
Brown rice was used as an object to be treated, and adult larvae bred in advance were mixed in the brown rice. The conveyor speed was adjusted so that the time required for the brown rice containing adults to pass through the vicinity of the high-frequency electrode was 1 to 3 seconds, and the thickness of the object to be processed was about 5 mm with a thickness adjuster. The frequency of the oscillator was set to 40.68 MHz, and the voltage between the electrodes was set to 3 KV to 4 KV. The electrodes are formed by arranging round bars, which are conductors having a diameter of 4 mm, on the same plane as shown in FIGS. 2 and 3 at intervals of 10 mm. When brown rice was treated under these conditions, all of the beetles in the brown rice after the treatment were dead. Brown rice itself is also heated by high-frequency power, but the surface temperature is 50 ° C. or less and the heating time is extremely short, so no influence on the quality was observed.

Next, the result of processing eggs that are said to have high resistance to heat insecticide and frozen insecticide, which are generally used, is shown. The brown rice in which the eggs of B. elegans were laid in advance was used as the object to be treated. The conveyor speed was adjusted so that the time required for the object to pass through the vicinity of the electrode was 8 seconds to 10 seconds, and the thickness of the object to be processed was about 5 mm with a thickness adjuster. The frequency of the oscillator was set to 40.68 MHz, and the voltage between the electrodes was set to 3 KV to 4 KV. The electrodes have the shape shown in FIG. 2 and FIG. 4 and are formed by arranging flat plates, which are conductors having a thickness of 2 mm and a width of 10 mm, on the same plane at intervals of 10 mm. Brown rice was treated under these conditions, and as a result of maintaining the temperature and humidity suitable for growth for one month necessary for normal eggs to become adults, no adults occurred. From this result, it was speculated that the eggs were killed in brown rice or were damaged to such an extent that they could not become adults. Brown rice itself is also heated by high-frequency power, but the surface temperature is 70 ° C or less, and the heating time is very short, so no effect on quality was observed.

By using this device to process foods such as cereals and spices and pharmaceuticals such as Chinese medicine, it is possible to kill insects, their eggs, or bacteria mixed in them in a short time. Quality can be maintained. This device, for example, can be used in combination with a foreign matter inspection device or a sorter for cereals or pharmaceuticals to prevent foreign matter from being mixed and at the same time to prevent the generation of pests and maintain good quality.

1 is an overall configuration diagram of a quality maintenance method and apparatus according to an embodiment of the present invention. It is a conceptual diagram explaining the arrangement | positioning of the high frequency electrode of the quality maintenance method and apparatus which concerns on embodiment of this invention, and connection with a high frequency oscillator. It is a three-dimensional conceptual diagram when a conductive round bar is used as an electrode in the high-frequency electrode of the quality maintaining device according to the embodiment of the present invention. It is a three-dimensional conceptual diagram at the time of using an electroconductive flat plate for an electrode in the high frequency electrode of the quality maintenance apparatus which concerns on embodiment of this invention. It is a conceptual diagram explaining another example of arrangement | positioning of the high frequency electrode of the quality maintenance apparatus which concerns on embodiment of this invention. It is an enlarged view explaining the high frequency electrode, to-be-processed object, and a pest of the quality maintenance method and apparatus which concern on embodiment of this invention. It is a schematic diagram explaining the difference of the temperature change of the to-be-processed object when processed using the quality maintenance method which concerns on embodiment of this invention, and processed using the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High frequency oscillator 2 High frequency electrode 3 Thickness adjuster 4 Supply hopper 5 Collection hopper
6 Conveyor 7 Ground side electrode 8 High voltage side electrode 9 Object 10 Conductor 11 Electric field 12 Pest

Claims (5)

A device that applies high-frequency power to foods and pharmaceuticals for the purpose of maintaining quality and kills pests, insect eggs, or bacteria, and a high-frequency oscillator that generates high-frequency power in the frequency range of 1 MHz to 300 MHz; It is equipped with electrodes that apply power to processed objects such as foods and pharmaceuticals, and the electrode structure has alternating high-voltage side electrodes and ground-side electrodes only on one side with no object to be processed in the vicinity of the object to be processed. One or more pairs are arranged at intervals, and the quality maintaining device for foods and medicines. A device that applies high-frequency power to foods and pharmaceuticals for the purpose of maintaining quality and kills pests, insect eggs, or bacteria, and a high-frequency oscillator that generates high-frequency power in the frequency range of 1 MHz to 300 MHz; It is equipped with an electrode that applies power to the object to be processed such as food, medicine, etc., and its structure has a gap between the high-voltage side electrode on one side of the object to be processed and the ground side electrode on the opposite side in the vicinity of the object to be processed A quality maintaining device for foods and pharmaceuticals, wherein one or more pairs are arranged with no gap and are not facing each other. In a heat treatment method for killing pests, pest eggs, or bacteria mixed in foods and pharmaceuticals, an oscillator that generates high-frequency power in the range of 1 to 300 MHz and one or more pairs in the vicinity of the object to be processed pass Pests and eggs of pests can be quickly applied while suppressing heat denaturation of foods, pharmaceuticals, etc., by applying high-frequency power to the objects to be processed that pass through the vicinity of the electrodes using the arranged electrodes. Or the quality maintenance method of the foodstuffs and pharmaceuticals characterized by killing bacteria. 4. The quality maintaining method according to claim 3, wherein an electrode for applying a high frequency has the structure according to claim 1. 4. The quality maintaining method according to claim 3, wherein an electrode for applying a high frequency has the structure according to claim 2.

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