JP3900038B2 - Cooked rice incubator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooked rice warmer that prevents yellowing of cooked rice, generation of a warm odor, and deterioration of taste properties, and eliminates the decay of cooked rice by bacteria.
[0002]
[Prior art]
Conventionally, in the warming of cooked rice in an induction heating type jar rice cooker, the temperature of the cooked rice is detected by a temperature detector in contact with the bottom of the inner pot, and a control unit is preset based on this detected value. Electric power is supplied to the heating coil so that the temperature is kept at a predetermined temperature, for example, 72 ° C., and the stainless steel layer of the clad material made of stainless steel and aluminum is heated by electromagnetic induction. In addition, the control unit electronically controls the input of the heat retaining heater on the inner pot side and the lid heater 10 mounted on the lid, so that the heating heat amount according to the amount of cooked rice is given, and the cooked rice temperature is set to 72 ° C., which is the temperature setting temperature. I try to keep it.
[0003]
In general, when the temperature of the cooked rice is increased, lipids, proteins and carbohydrates in the cooked rice cause an oxidation reaction with oxygen in the air, or a decomposition or polymerization reaction of these substances. Generation of warm odor and deterioration of taste properties occur. On the other hand, when the temperature is kept low, the rice rots due to bacteria. In order to solve these problems, various techniques have been developed so far.
[0004]
As one of the solutions to the above problem, a rice cooker as shown in FIG. 5 is known. This cooked rice warmer is equipped with an inner pot 30 for heating cooking by adding a predetermined amount of rice and water, and is heated by heating means 32. A temperature detecting means 33 is provided in contact with the bottom of the inner pot 30. The lid 34 of the inner pot 30 is provided with a pressure reducing device 35 that depressurizes the air in the inner pot 30 and a gas separation membrane 36 that allows only oxygen in the air to pass before the pressure reducing device 35.
[0005]
In this configuration, the temperature of the cooked rice is reduced by using the gas separation membrane 35 that exhausts the air in the inner pot 30 to reduce the absolute amount of oxygen in the inner pot 30 or passes only oxygen. In this method, only the oxygen in the inner pot 30 is discharged to reduce the absolute concentration of oxygen while lowering the oxygen concentration, thereby preventing yellowing of cooked rice and the generation of a warming odor.
[0006]
[Problems to be solved by the invention]
However, the conventional configuration is a configuration in which the air in the inner hook 30 is discharged by the decompression device 35, which requires a high degree of hermeticity in the inner hook 30, and the configuration is complicated. Maintaining hermeticity is extremely difficult and has become a kind of pressure vessel, and thus has a problem that it is difficult to configure for general household use.
[0007]
In addition, when the temperature is kept for several hours, the airtightness is lost, the air flows in, the oxygen concentration in the inner pot 30 increases, and the cooked rice deteriorates due to the temperature keeping. In addition, a large amount of water is present in the inner pot 30 after cooking, and the inner pot 30 is saturated water vapor. When this air is discharged, the large amount of water is reduced by the decompression device 35 or the gas separation membrane 36. The problem is that the capacity of the gas separation membrane 36 and the like is reduced, the moisture condensed on the gas separation membrane 36 and the like flows back into the inner pot 30, and the water accumulated in the piping and the gas separation membrane 36 and the like. There was a problem of corruption.
[0008]
The present invention solves the above-mentioned conventional problems, and prevents yellowing of cooked rice, generation of a warming odor, deterioration of taste physical properties, eliminates spoilage of cooked rice, and obtains cooked cooked rice even when kept warm. The purpose is to provide a cooked rice cooker.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the cooked rice warmer of the present invention is configured to send nitrogen-enriched air to the inner pot for storing cooked rice when the cooked rice is kept warm.
[0010]
This disperses the unpleasant warming odor generated in the inner pot, prevents yellowing of the cooked rice, the generation of warming odor, and the deterioration of the physical properties of the food. Obtainable.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is a solid electrolyte having oxygen ion conductivity, a pair of electrodes formed on different surfaces of the solid electrolyte, a voltage supply device connected between the pair of electrodes, A heater for heating a solid electrolyte, a heater power source for supplying a voltage to the heater, a porous and breathable heat insulating material provided around the solid electrolyte and the heater, and a pair of electrodes formed on each other A nitrogen supply means that removes oxygen contained in the atmosphere and generates nitrogen-enriched gas, which is composed of a sealing material that separates different spaces in an airtight manner, an inner pot that contains cooked rice, and an upper part of the inner pot A lid that can be opened and closed; heating means for heating the cooked rice in the inner pot; temperature detecting means for detecting the temperature of the inner pot; gas transport means for transporting the nitrogen-enriched gas to the inner pot; The temperature detecting means Based on the detected value, by heating the cooked rice to a predetermined temperature by the heating means, and a rice cooker comprising a control means for controlling the nitrogen supply amount by the nitrogen supply means and the gas transport means. Disperses the unpleasant warming odor generated in the inner pot, prevents yellowing of the cooked rice, the generation of warming odor, and the deterioration of the taste and physical properties. Can do.
[0012]
In addition, the oxygen pumping action of the solid electrolyte efficiently removes only the oxygen contained in the external air, and the lipids, proteins and carbohydrates in the cooked rice oxidize with the oxygen in the air, and these substances decompose or polymerize. It is possible to reduce the yellowing of cooked rice and the generation of a warm odor.
[0013]
In addition, the oxygen pumping action of the solid electrolyte efficiently removes only oxygen contained in the outside air, supplies nitrogen-enriched gas, and reduces the oxygen concentration in the inner pot. It can delay the decay of cooked rice.
[0014]
In addition, the nitrogen-enriched air separated from one electrode (cathode) and the oxygen released from the other electrode (anode) are separated without mixing, so nitrogen-rich gas can be supplied efficiently. Can do.
[0015]
In addition, the gas flows in and out sufficiently, and oxygen exchange is performed between the outside and the pair of electrodes without delay, so that a nitrogen-enriched gas can be supplied efficiently.
[0016]
The invention described in claim 2 is a cooker incubator according to claim 1, wherein a valve is provided between the nitrogen supply means and the inner pot, and the nitrogen supply means and the inner pot are isolated by the valve during rice cooking. As a result, water vapor and rice balls generated by rice cooking do not adhere to the nitrogen supply means and the like, so that the nitrogen supply capability can be maintained for a long time.
[0017]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0018]
FIG. 1 shows a jar rice cooker, and 1 is an inner pot equipped in a main body 2, and a predetermined amount of rice and water 3 are added to perform cooking. A temperature detecting means 4 for detecting the temperature of the inner hook 1 is provided at the bottom of the inner hook 1 so as to contact the inner hook 1, and a heating means 5 comprising an electromagnetic induction heating coil for heating the inner hook 1 is provided. It has been. Reference numeral 6 denotes a control means, which is also provided with a high frequency power source for supplying power to the heating means 5. Further, a heating means 7 serving as a heat retaining heater is provided on the upper side of the side of the inner pot 1, a heating means 10 serving as a lid heater is provided on a heat radiating plate 9 below the lid 8, and a lid temperature detecting means 11 for detecting the temperature of the inner pot 1. Is provided.
[0019]
Further, the lid 8 is provided with a nitrogen supply means 15 for removing oxygen contained in the atmosphere and supplying a nitrogen-enriched gas, and a gas transport means 16 comprising a pump, a fan, etc. for carrying the gas. The air is guided to the nitrogen supply means 15 through the opening by driving the gas transport means 16, and is separated into nitrogen and oxygen by the nitrogen supply means 15, and the oxygen is again returned to the outside through the nitrogen supply means 15 from the opening. Released.
[0020]
On the other hand, the separated nitrogen is again mixed with the atmosphere to become a nitrogen-enriched gas, and is led into the inner pot 1 by the suction action of the gas transport means 16. As a result, the inside of the inner pot 1 is replaced with a nitrogen-enriched gas, and the gas containing high-concentration oxygen present in the inner pot 1 is discharged to the atmosphere by the gas transport means 16. The opening that discharges the gas in the inner pot 1 to the atmosphere also serves as a steam vent during rice cooking.
[0021]
A check valve 17 is provided so that a gas containing high-concentration oxygen does not flow back from the inner pot 1 to the nitrogen supply means 15, and a valve 18 is provided between the nitrogen supply means 15 and the inner pot 1. Thus, the nitrogen supply means 15 and the inner pot 1 can be isolated. Therefore, since water vapor and rice balls generated by rice cooking do not adhere to the nitrogen supply means 15 and the gas transport means 16 and the like, the nitrogen supply capability can be maintained for a long time, and water condensed on the piping and the nitrogen supply means 15 etc. Since it does not accumulate, it is unlikely to rot and the cooked rice warmer can be kept clean for a long time. Moreover, since the back flow of the gas with a high oxygen concentration is prevented, the oxygen concentration in the inner pot 1 can be efficiently kept low all the time.
[0022]
An operation panel 12 is provided on the top of the lid 8, and a lid opening / closing detection means 19 is provided at a place where the main body 2 and the lid 8 are in contact with each other. The open / close detection means 19 is configured as a reed switch, and the control means 6 detects the open / closed state of the lid 8 based on information from the open / close detection means 19. In this figure, connections such as power lines and signal lines are omitted.
[0023]
In this jar rice cooker, the temperature of the cooked rice is detected by the temperature detection means 4 in contact with the bottom of the inner pot 1. This information is sent to the control means 6, and the heating means 5 is supplied with electric power to generate a magnetic force so that the temperature of the cooked rice becomes 72 ° C., which is the heat retention set temperature, and is composed of a clad material made of stainless steel and aluminum. The stainless steel layer of the inner pot 1 is heated by electromagnetic induction to keep the cooked rice warm. Further, the control means 6 electronically controls the input of the heat retaining heater 7 and the lid heater 10 to give a heating heat amount corresponding to the amount of cooked rice, and keep the cooked rice temperature at the heat retaining set temperature 72 ° C.
[0024]
Further, the control means 6 controls the nitrogen supply means 15 and the gas transport means 16 to continuously supply the nitrogen-enriched gas or to disperse the warming odor in the inner pot 1 by intermittent supply that repeats the supply at regular intervals. Even if the lid 8 is sealed for a long time, it is possible to provide a delicious cooked rice by suppressing yellowing of the cooked rice and deterioration of physical properties during eating.
[0025]
As shown in FIG. 2, the nitrogen supply means 15 includes an oxygen pump composed of a solid electrolyte 20 having oxygen ion conductivity, a pair of electrodes 21 and 22 formed on different surfaces of the solid electrolyte 20, and a solid state. A heater 24 for heating the electrolyte 20 is provided. A voltage supply device 23 for supplying voltage is connected between the pair of electrodes 21 and 22, and a heater power source 25 is connected to the heater 24. Further, in order to efficiently heat the solid electrolyte 20 with the heater 24, a heat insulating material 26 is provided around the periphery. Since the heater 24 is embedded in the heat insulating material 26 and formed integrally, the nitrogen supply means 15 can be reduced in size.
[0026]
Further, since the heat insulating material 26 is porous and has air permeability, the gas can flow in and out sufficiently, and oxygen can be exchanged between the outside and the pair of electrodes 21 and 22 without delay, and the nitrogen-rich material can be efficiently enriched. Gas can be supplied.
[0027]
Further, the solid electrolyte 20 is airtightly fixed to the heat insulating material 26 and the metal casing through the sealing material 27, and the nitrogen-enriched air separated by one electrode 21 (cathode) and the other electrode 22 ( Oxygen released from the anode) is separated without mixing, and a nitrogen-enriched gas can be supplied efficiently.
[0028]
The solid electrolyte 20 is a disk made of lanthanum gallium oxide having oxygen ion conductivity and having a diameter of about 20 mm and a thickness of 1 mm. A paste made of perovskite oxide is printed on both sides as a pair of electrodes 21 and 22 and dried. Thereafter, a current collector was further laminated thereon, and a sealing material 27 made of metal foil and a lead wire were attached and fired in an electric furnace. For the solid electrolyte 20, stabilized zirconia, stabilized ceria and the like having other oxygen ion conductivity can also be used. In order to improve the oxygen ion conductivity of the lanthanum gallium oxide used in the examples, lanthanum site Further, a dissimilar metal such as a transition metal or an alkaline earth metal may be substituted for a part of the gallium site.
[0029]
FIG. 3 shows voltage-current characteristics of the oxygen pump configured as described above.
[0030]
The atmosphere taken in from the outside reaches one electrode 21 (cathode) through the porous heat insulating material 26, and oxygen contained in the atmosphere is adsorbed on the cathode 21. When a voltage is applied between the pair of electrodes 21 and 22 by the voltage supply device 23, the adsorbed oxygen receives electrons and is solid from a three-phase interface formed between the cathode 21, the solid electrolyte 20, and the gas phase. It is taken into the electrolyte 20 and becomes oxygen ions and moves through the solid electrolyte 20. Oxygen ions that have reached the other electrode 22 (anode) emit electrons at the three-phase interface formed between the anode 22, the solid electrolyte 20, and the gas phase, become oxygen again, and are discharged to the atmosphere. The nitrogen-enriched gas from which oxygen has been removed is supplied to the inner pot 1 by the gas transport means 16 and is replaced with a gas containing high-concentration oxygen. A gas containing high-concentration oxygen is discharged to the outside.
[0031]
As a result, the inner pot 1 has a low oxygen concentration, and it is suppressed that lipids, proteins and carbohydrates in the cooked rice are oxidized with oxygen in the air, and these substances are not decomposed or polymerized. The occurrence of yellowing and warming odor can be reduced. Moreover, the activity of bacteria can be suppressed and the decay of cooked rice can be delayed.
[0032]
The jar rice cooker comprised as mentioned above was investigated about the heat retention state of cooked rice. The oxygen concentration of the gas in the inner pot 1 immediately after cooking was almost 0%, but the inside was cooled and the saturated vapor pressure was lowered, and air flowed in from the outside, and the oxygen concentration gradually increased.
[0033]
Therefore, 10-20 W of electric power is supplied to the heater 24 of the nitrogen supply means 15 using the heater power supply 25, and the operating temperature of the oxygen pump composed of the solid electrolyte 20 and the pair of electrodes 21, 22 is 600-700 ° C. It heated so that it might become. A predetermined voltage was supplied between the pair of electrodes 21 and 22 by the voltage supply device 23, and the gas transport means 16 was further operated to take in air from the outside. The nitrogen supply amount can be changed by controlling the voltage supply device 23 and the gas transport means 16.
[0034]
FIG. 4 is a view showing the relationship between the heat retention time and the oxygen concentration in the inner pot 1 when the air in the inner pot 1 is replaced with a nitrogen-enriched gas by the nitrogen supply means 15. Oxygen separated by the oxygen pump is discharged to the outside at 10 to 30 cc per minute, and the separated nitrogen is mixed with air again to become a nitrogen-enriched gas, and continuously into the inner pot 1 at 40 to 120 cc per minute. Supplied. The air in the inner pot 1 was gradually replaced with nitrogen-enriched gas, and the oxygen concentration in the inner pot 1 became 2 to 4% in 20 to 60 minutes. Therefore, the nitrogen supply amount was reduced and held as it was. After a while, the oxygen concentration in the inner pot 1 increased due to the inflow of external air. However, the oxygen concentration in the inner pot 1 can be quickly reduced by increasing the nitrogen supply amount again at a certain low concentration stage. did it. Further, at this time, it was found that the inside of the inner pot 1 is almost at atmospheric pressure, and the airtight structure is simple.
[0035]
Immediately after cooking, sensory evaluation was performed when the oxygen concentration in the inner pot 1 was maintained at 2 to 4%. When kept in the atmosphere as in the past, the rice was slightly oxidized, and the evaluation of the warming odor and taste was low, whereas when kept at a low oxygen concentration, the warming odor was low and the taste It was good too.
[0036]
Furthermore, when the sensory evaluation of the cooked rice that had been kept warm for 12 hours and 24 hours in this state, both had a little warming odor, had a freshly cooked odor, little yellowing, sticky taste evaluation, and elasticity The overall evaluation was high. On the other hand, the cooked rice that had been kept warm for 12 hours and 24 hours in the atmosphere as in the past had a strong warming odor, yellowing occurred, the taste was poor, and the overall evaluation was low.
[0037]
Next, the heat insulation state of the cooked rice when the lid 8 was opened and closed was examined. Immediately after the lid 8 was opened, the oxygen concentration in the inner pot 1 became equal to the oxygen concentration in the atmosphere and became 20.8%. When the lid 8 was closed, the open / close detection means 19 detected the closure of the lid 8, and the nitrogen supply means 15 and the gas transport means 16 were activated. The air in the inner pot 1 was gradually replaced with nitrogen-enriched gas, and the oxygen concentration in the inner pot 1 became 2 to 4% in 20 to 60 minutes. Therefore, the nitrogen supply amount was reduced and held as it was. After a while, the oxygen concentration in the inner pot 1 increased due to the inflow of external air. However, the oxygen concentration in the inner pot 1 can be quickly reduced by increasing the nitrogen supply amount again at a certain low concentration stage. did it.
[0038]
The sensory evaluation of the cooked rice when the lid 8 was opened and closed also showed comprehensively good results such as a warm odor, yellowing of cooked rice, and physical properties of the taste. Moreover, it turned out that delicious cooked rice with little heat retention odor can be provided by changing supply_amount | feed_rate of nitrogen-enriched gas according to the quantity of cooked rice to heat retention.
[0039]
【The invention's effect】
As described above, according to the cooked rice incubator of the present invention, by sending nitrogen-enriched air into the inner pot, the unpleasant warming odor generated in the inner pot is scattered, and the yellowness or taste of the cooked rice is reduced. Can suppress the deterioration of physical properties of food, and can provide delicious cooked rice even if it is kept warm [Brief description of the drawings]
1 is a schematic cross-sectional view of a rice cooker according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a nitrogen supply unit of the rice cooker. FIG. 3 is a voltage-current characteristic diagram of the nitrogen supply unit. ] Characteristic diagram showing the relationship between the incubation time and oxygen concentration of the rice cooker [Fig. 5] Cross-sectional view of a conventional rice cooker [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner pot 4,11 Temperature detection means 5, 7, 10 Heating means 6 Control means 8 Cover 15 Nitrogen supply means 16 Gas transport means 17 Check valve 18 Valve 19 Opening / closing detection means 20 Solid electrolyte 21, 22 Electrode 23 Voltage supply device 24 heater 25 heater power supply 26 heat insulating material 27 sealing material

Claims (2)

A solid electrolyte having oxygen ion conductivity; a pair of electrodes formed on different surfaces of the solid electrolyte; a voltage supply device connected between the pair of electrodes; a heater for heating the solid electrolyte; A heater power supply for supplying a voltage to the heater, a porous electrolyte and an air-permeable heat insulating material provided around the solid electrolyte and the heater, and a sealing material for airtightly separating different spaces in which a pair of electrodes are formed A nitrogen supply means that removes oxygen contained in the atmosphere and generates a nitrogen-enriched gas, an inner pot that contains cooked rice, a lid that can be opened and closed above the inner pot, The heating means for heating the cooked rice in the inner pot, the temperature detecting means for detecting the temperature of the inner pot, the gas transport means for transporting the nitrogen-enriched gas to the inner pot, and the detected value of the temperature detecting means And Cooked rice warmer comprising a control means for controlling the nitrogen supply amount by the nitrogen supply means and the gas transport means while heating the rice to a predetermined temperature by means.   The cooked rice warmer according to claim 1, wherein a valve is provided between the nitrogen supply means and the inner pot, and the nitrogen supply means and the inner pot are isolated by the valve during rice cooking.

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