JPH0632024Y2 - rice cooker - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Use) The present invention relates to a rice cooker that heats rice, which is rice to be cooked, and water by heating means to cook the rice.

(Prior Art) A conventional rice cooker of this type includes a bowl body having a heating means, a container that can be inserted into and removed from the bowl body, and a lid that opens and closes an upper opening of the bowl body. A predetermined amount of rice and water are contained in the container, the container is contained in the main body of the container, the lid is closed, and the container is heated by the heating means.

When cooking rice under normal pressure, rice is cooked as follows except under conditions of high altitude or low pressure. That is, the water temperature in the container gradually rises in response to the heating by the heating means, and the starch quality of the rice in the container gradually changes from β starch to α starch (hereinafter referred to simply as α conversion). The gelatinization of rice begins at a water temperature of 55-70 ℃ in the container, but the degree of progress of gelatinization is very slight within this temperature, and it becomes active after the water temperature reaches a boiling state of 98 ℃ or more. Then, under such a boiling state, the water in the container is actively absorbed by the rice, and when the cooking temperature is detected, the heating means is temporarily cut off, and the process shifts to the Murashi stroke, and during the Murashi stroke. The heating means is controlled so that the temperature does not decrease, and after the unevenness stroke, the heat retention stroke is started. Normally, rice becomes edible when all is pregelatinized at about 98 ° C for about 20 minutes while water is present.

Such a normal pressure rice cooker has a problem that it cannot cook delicious sticky rice due to the quality of rice. It is said that when rice becomes edible rice, it is generally more sticky to be suitable for the Japanese food culture. To make sticky rice, the amount of amylose contained in the starch granules that form the rice is It is known that less is better. Also lipid content,
Although protein content may be considered as an element, the stickiness is particularly increased when the content of amylopectin and amylose in starch granules forming rice is low. Rice quality and climatic conditions are important as conditions for producing rice with a low amylose content. Especially, in climatic conditions, the temperature during rice ripening is 18 to 24 ° C, preferably 22 to 23 ° C. It is said to be good.
Therefore, the quality of rice varies depending on the production area and the weather conditions even if the variety is the same, and even the sticky variety may become less sticky. Rice with a strong stickiness is not a problem, but rice with a low stickiness makes cooked rice less sticky and harder and less tasty.

Therefore, as a method to give sticky rice stickiness and improve the eating quality, make the heating time until boiling longer than usual,
There is also a method in which even after boiling, the boiling duration is lengthened with a weaker heating amount and heating is slowly performed to soften the outer peripheral portion of the rice grain in a slightly boiling state to make it sticky. However, this is not a delicious rice because it simply softens with the phenomenon of boiling down and gives a little stickiness, and the hardness and tenacity which are the original deliciousness of rice are not removed.

Pressurized rice is another method. According to this method, the cell walls of the starch granules forming rice are more likely to be broken than under normal pressure, and heat and water penetrate into the starch granules more rapidly than the broken cracks to accelerate pregelatinization. As a result, if the steam temperature and boiling duration (equivalent to 20 minutes at 98 ° C or higher) for α-αization at the same level as at normal pressure are secured, the α-α-type of rice will be more complete than at atmospheric pressure, and the cell wall The large breakage softens the starch granules and increases the stickiness. With this rice cooking method, moderate hardness and tenacity can be secured without causing sticking phenomenon even with less tenacious rice. However, a pressure cooker is generally used for this pressure cooked rice, and this pressure cooker usually has a steam temperature of 110 ° C.
In order to adjust the vapor pressure in the container, the heating amount of the heating means or the size of the steam port is changed, and when the container temperature reaches the predetermined temperature, the heating means is turned off. However, pressure cooked rice with a pressure cooker does not stick to low amylose rice, etc., which has sticky characteristics, because it does not consider the detection of steam temperature in the container and the limitation of the heating amount based on steam temperature. Is too strong, and there is a problem that sugar and amino acids turn yellow due to Maillard reaction because rice is exposed to steam at a high temperature of about 110 ° C for a long time. There is a problem that you cannot do it.

(Problems to be solved by the invention) As described above, in the above-mentioned conventional technique, in order to give stickiness to rice, when the heating time until boiling is lengthened by normal pressure cooked rice and the boiling time is also lengthened, hardness and The stickiness is not well balanced and the taste is not good, and when pressure cooked rice is cooked with a pressure cooker, the stickiness of the rice becomes too strong or it turns yellow and the boiling duration of 98 ° C or more is maintained. There was a problem that we could not secure it and could not obtain delicious rice.

Therefore, an object of the present invention is to provide a rice cooker capable of providing stickiness to rice to improve the eating quality and ensuring the boiling duration.

[Structure of the Invention] (Means for Solving the Problem) The present invention is a container body 1 for accommodating a container 7, a lid 17 for sealing an upper opening of the container 7, and a heating means 5 for heating the container 7. A container temperature detecting means 30 for detecting the temperature of the container 7, an air temperature detecting means 31 for detecting the temperature of the air in the container 7, and an air temperature detecting means at the initial boiling stage.
After the detected temperature of 31 reaches a predetermined temperature higher than the steam temperature at normal pressure, the heating amount of the heating means 5 is reduced, and thereafter the input of the heating means 5 is input based on the detected temperature of the container temperature detection means 30. And a rice cooking control means 39 for controlling.

(Operation) According to the present invention, the input of the heating means 5 is controlled based on the temperature detected by the air temperature detecting means 31 in the initial stage of boiling, and then the input of the heating means 5 is changed based on the detected temperature of the container temperature detecting means 30. Controlled.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 4, reference numeral 1 denotes a bowl body, and the bowl body 1 is configured to include an outer case 3 and an inner case 4 connected by an upper frame body 2, and a rice cooking heater serving as a heating means at an inner bottom portion of the inner case 4. 5 is provided and a heat retention heater 6 is provided on the side. Reference numeral 7 denotes a container that is removably housed in the inner case 4, and a cup-shaped heat-sensitive portion 8 is provided in the inner case 4 so as to elastically press the outer bottom portion of the container 7. The container 7 contains rice 9 and water 10 which are rice to be cooked. Inside the heating unit 8, a container temperature sensor 11 for detecting the container temperature is enclosed by a heat conductive mold member 12. Reference numeral 13 denotes a lid pivotally installed so as to open and close the upper opening of the vessel body 1. The lid 13 has a hollow structure and is provided with a steam outlet portion 14, and the hollow portion of the lid 13 has a heat retaining heater. 6 are provided. Reference numeral 15 is a cylindrical stud provided at the center of the lower surface of the lid 13, and the bush 16 is provided on the stud 15.
The inner lid 17 is suspended via the inner lid 17, and the inner lid 17 has a packing 18 on the outer peripheral edge portion so that the upper opening of the container 7 can be elastically closed. The inner lid 17 is elastically pressed against the upper opening of the container 7 via a bush 16 made of an elastic material such as silicon rubber, and is kept sealed by a packing 18. When the temperature becomes too high (air temperature is about 110 ° C), the inner lid 17 is pushed up against the pressing force of the bush 16 by the vapor pressure, and the vapor is discharged from the gap between the inner lid 17 and the container 7. ing. In this case, a stainless steel spring or the like may be used instead of the bush 16. Reference numeral 19 denotes a cup-shaped heat-sensitive portion provided at the lower end of the stud 15 so as to face the inside of the container 7. Inside the heat-sensitive portion 19, an air temperature sensor 20 for detecting the temperature of the air inside the container 7 has heat conductivity. Mold member 21
It is enclosed by. Reference numeral 22 denotes an electronic circuit unit provided at the bottom of the bowl body 1, which controls inputs of the rice cooking heater 5 and the warming heater 6 based on temperature detection information of the container temperature sensor 11 and the air temperature sensor 20. .

FIG. 7 shows an operation panel 23 comprising a display means 23A and an operation means 23B, and the display means 23A has three LEDs 24, 24A, 24B.
There is a course display part consisting of, this course display part is white rice cooked normal (normal pressure rice), white rice cooked stronger (pressurized rice),
The rice porridge is displayed in the order of cooking, and the selected course is lit up. The display means 23A further includes two LEDs 25, 25
It has a mode display part consisting of A, which lights up and displays the mode that is being processed, such as rice cooking and heat retention. Operating means 23B
Has a start switch 26 as a rice cooking starting means, a course switch 27 as a course selecting means, and a cancel switch 28.

1 and 5 are block diagrams showing the electrical configuration,
Reference numeral 29 denotes an A / D converter that constitutes the container temperature detecting means 30 together with the container temperature sensor 11 and the air temperature detecting means 31 together with the air temperature sensor 20 and outputs a signal corresponding to the detected temperature. . Reference numeral 32 is a control means composed mainly of a microcomputer which mainly constitutes the electronic circuit unit 22, and has a CPU 33, a timer circuit 34, a memory 35, an input circuit 36, an output circuit 37 and the like, as is well known. The control means 32 has a plurality of types of heating patterns, and the course determination means 38 determines the selected heating pattern based on the signal of the course switch 27, which is the course selection means, and the boiling from the start of rice cooking according to the set heating pattern. Until the initial stage, the inputs of the heaters 5 and 6 are controlled based on the temperature detected by the air temperature detecting means 31 to reduce the heating amount under a predetermined temperature condition, and then the inputs of the heaters 5 and 6 are detected based on the temperature detected by the container temperature detecting means 30. And rice-cooking control means 39 for controlling. Further, the control means 32 is a heater drive circuit according to the operation signal of the operation means 23B and the temperatures detected by the container temperature detection means 30 and the air temperature detection means 31.
The heaters 5 and 6 are driven and controlled by 40, and the display means 23A is driven and controlled by the display drive circuit 41.

FIG. 6 shows a circuit diagram of the power supply unit and the heater drive unit.
Is a commercial power source, and a rice cooking heater 5, a warming heater 6 and a triac 43 are connected in series between both terminals.
A relay in the series circuit of the heat insulation heater 6 and the triac 43
The normally open relay switch 44A that constitutes 44 is connected in parallel. Reference numeral 45 is a power supply transformer, and a predetermined power supply voltage is supplied to the microcomputer as the control means 32 via the power supply transformer 45 and the constant voltage circuit 46. This control means 32
Inputs temperature signals of the container 7 and the air in the container 7 from two thermistors, which are the temperature sensors 11 and 20. Also control means
32 is the excitation coil 44 of the relay 44 via the relay drive circuit 47
While exciting B, the triac 43 is driven through the triac drive circuit 48 to control the inputs of the rice cooking heater 5 and the heat retention heater 6.

First, to explain the course selection operation, as shown in the flowchart of FIG. 8, the white rice cooking normal course (normal pressure rice) is set in the canceled state, and the start switch 26 is pressed to make the white rice cooking normal course described later. Is executed. Also, each time the course switch 27, which is the course selection means, is pressed, the course determination means 38 causes the white rice to cook a normal course (normal pressure rice), the white rice to strengthen the course (pressurized rice), the porridge rice course, the white rice cooked normal course (normal pressure rice). Are set in sequence and LED24,24A, 2
The 4B lighting display shifts.

The control by the heating pattern of the white rice cooked course (pressurized rice) will be described with reference to the flowchart of FIG. 2 and the graph of FIG. First, 10 for rice heating heater 5
Continuously energize with 0% input (step 1). After that, the rice cooking control means 39 mainly performs the following control based on the detected air temperature T ₁ , and determines whether or not the following three conditions are satisfied.
The first condition is that the air detection temperature T ₁ of the air temperature detection means 31 is a predetermined temperature P higher than the steam temperature at normal pressure (98 ° C. or higher).
₂ (around 105 ° C) or higher (step 2).
The second condition is whether the gradient of the detected air temperature T ₁ (see the solid line curve in FIG. 3) has a rise width within a fixed time t _{2 of} not more than the temperature R ₂ (step 3). The third condition is whether or not the gradient of the container detection temperature T ₂ of the container temperature detection means 30 (see the one-dot chain line in FIG. 3) is such that the rising width within a certain time t ₁ is the temperature R ₁ or less (step 4). ). When these conditions are satisfied, the rice-cooking control means 39 controls the rice-cooking heater 5 to turn off the power for 30 seconds and to turn on the power for 20 seconds (40% input) to reduce the heating amount (step 5). Rice control means 39 thereafter proceeds to a control based on the vessel detected temperature T _2, it is determined whether or not reached in the container detected temperature T ₂ is cooked-up temperature P (120 ° C.) (Step 6). When T ₂ ≧ P is reached, the rice cooking heater 5 is turned off and the process shifts to the unevenness stroke (step 7). This rice cooker heater 5 should be kept boiling for about 15 minutes.
To control. In the above control, the maximum value P ₂ of the air detection temperature T ₁ shown in FIG. 9 is the maximum value P ₁ of the container detection temperature T _2.
Set higher. In addition, in the above control, the heating amount is reduced when the three conditions are satisfied, but in step 2, the detected air temperature T ₁ is the predetermined temperature P ₂ (10
When the temperature reaches about 5 ° C.), the heating amount may be reduced by moving to step 5, or when the conditions of step 3 and step 4 are satisfied without passing through step 1 and step 2. The amount of heating may be decreased by shifting to step 5.

The control by the heating pattern of the white rice cooking ordinary course (normal pressure rice cooking) will be described with reference to the flowchart of FIG. 9 and the graph of FIG. First, for the rice cooker 5
Energize continuously with 100% input (step 1). After that, the rice cooking control means 39 mainly performs the following control based on the detected air temperature T ₁ , and determines whether or not the following three conditions are satisfied. The first condition is the detected air temperature T of the air temperature detecting means 31.
Whether ₁ has reached a predetermined temperature P ₃ (98 to 100 ° C.) or higher (step 2). The second condition is whether or not the gradient of the detected air temperature T ₁ (see the solid curve in FIG. 10) has a rise width within a constant time t ₃ of a temperature R ₃ or less (step 3). The third condition is the gradient of the container detection temperature T ₂ of the container temperature detection means 30 (tenth
The one-dot chain line curve in the figure) indicates whether or not the rise width within a constant time t ₁ is below the temperature R ₁ (step 4). When these conditions are satisfied, the rice cooking control means 39 instructs the rice cooking heater 5 to
30 second power interruption-20 second power conduction interruption control (40% input) to reduce the heating amount (step 5). After this rice cooking control means
39 proceeds to the control based on the vessel detected temperature T _2, it is determined whether or not reached in the container detected temperature T ₂ is cooked-up temperature P (120 ° C.) (Step 6). When T ₂ ≧ P is reached, the rice cooking heater 5 is turned off and the process shifts to the unevenness stroke (step 7). In this purging process, the rice cooking heater 5 is controlled so as to maintain the boiling state for about 15 minutes.

The control by the heating pattern of the rice porridge cooking rice course will be described with reference to the graph of FIG. 11. Steps 1 to 5 shown in the flowchart of FIG. 9 are the same as those of the normal rice cooking course (normal pressure rice cooking). The reduction of the heating amount in step 5 is controlled by 50% input to the rice cooking heater 5, and after a predetermined time, the control is switched to 10% input to the rice cooking heater so that boiling at normal pressure can be continued.

FIG. 12 shows a case where the container detection temperature T ₂ reaches the boiling temperature earlier than the air detection temperature T _{1 in the} strong rice cooking course (pressurized rice cooking). When the three conditions are satisfied similarly to the control of the rice bran strengthening course described with reference to FIG. 3, or when the two conditions of step 3 and step 4 are satisfied,
Alternatively, when the condition of step 2 is satisfied, step 5
Control may be performed so that the heating amount is decreased by shifting to.

As described above, in the above-described embodiment, as shown in the rice cooked and strengthened course (pressurized rice cooking), the input of the rice cooking heater 5 is controlled mainly by the air temperature detected by the air temperature detecting means 31 during the boiling stage during the rice cooking under pressure. And when the predetermined conditions are satisfied,
That is, the heating amount of the rice cooking heater 5 is reduced after the inside of the container 7 reaches a vapor temperature higher than that under normal pressure based on the detected air temperature, and thereafter, based on the detected temperature by the container temperature detecting means 30 under normal pressure conditions. Since the input of the rice-cooking heater 5 is controlled to continue the rice-cooking, the stickiness of the rice becomes too strong due to being exposed to a high temperature condition for a long time during the rice-cooking as in the case of using a conventional pressure cooker. It is possible to prevent yellowing and improve the accuracy of detecting the cooked state and ensuring the boiling duration by performing the control after boiling based on the container detection temperature, and it is possible to prevent overheating. It is possible to prevent the occurrence of a half-cooked state due to charring or insufficient heating, and it is possible to obtain delicious rice with a well-balanced hardness and tenacity. At the end of rice cooking, the pressure is normal, so there is no need to worry about opening the lid under high pressure, which is safe. Further, in a pressure cooker that cooks rice in a pressurized state, the pressure state is maintained for a predetermined time from the beginning of boiling, and the heater is turned off to stop heating after the timer operation or after reaching a predetermined time, After heating is stopped, the heater remains disconnected even if the container temperature changes, and reheating is not performed even when the container temperature falls below 98 ° C. However, in the present invention embodiment, boiling continues based on the container temperature. Since the heater is controlled so that there is no insufficient heating, the boiling duration of 98 ° C or more and about 20 minutes can be secured, and delicious rice can be obtained.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the embodiment of the present invention, it is possible to select either pressure cooked rice or normal pressure cooked rice, but the cooker may be configured as a dedicated cooked rice cooker shown in FIGS. 1 to 3. The basic structure of the rice cooker can be applied to various types, and the mounting structure of the temperature sensor constituting the air temperature detecting means may be appropriately selected so that the air temperature in the container can be detected.

[Advantages of the Invention] The present invention reduces the heating amount of the heating means after the temperature detected by the air temperature detecting means 31 reaches a predetermined temperature higher than the steam temperature at normal pressure in the early stage of boiling, and then the container temperature is increased. By controlling the input of the heating means based on the above, it is possible to provide a rice cooker that can give stickiness to rice to improve the eating quality and ensure the boiling duration.

[Brief description of drawings]

1 to 12 show an embodiment of the present invention, FIG. 1 is a block diagram, FIG. 2 is a flow chart showing control of pressure cooked rice, and FIG. 3 is pressurization heating pattern of rice bran strengthening course FIG. 4 is a cross-sectional view of the rice cooker, FIG. 5 is a block diagram showing the electrical configuration of the rice cooker, FIG. 6 is a circuit diagram of a power supply unit and a heater driving unit, and FIG. 7 is an operation. Front view showing the panel, FIG. 8 is a flow chart showing the operation of the course selecting means, FIG. 9 is a flow chart showing the control of normal pressure rice cooking, and FIG. 10 is a graph showing the control by the normal pressure heating pattern of the white rice cooking normal course. FIG. 11 is a graph showing the control according to the heating pattern of the porridge cooking course, and FIG. 12 is a graph showing another example of the control according to the pressure heating pattern of the rice rice strengthening course. DESCRIPTION OF SYMBOLS 1 ... Bowl body 5 ... Rice cooking heater (heating means) 7 ... Container 17 ... Inner lid (lid) 30 ... Container temperature detecting means 31 ... Air temperature detecting means 39 ... Rice cooking control means

Claims (1)

[Scope of utility model registration request] 1. A container body for accommodating a container, a lid for sealing an upper opening of the container, heating means for heating the container, container temperature detecting means for detecting the temperature of the container, and inside the container. Air temperature detecting means for detecting the temperature of the air,
In the initial stage of boiling, the detected temperature of the air temperature detecting means reaches a predetermined temperature higher than the steam temperature at normal pressure, and then the heating amount of the heating means is decreased, and thereafter, based on the detected temperature of the container temperature detecting means, A rice cooker comprising: rice cooker controlling means for controlling an input of the heating means.