JP2004344568A - Rice cooker and rice cooking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To offer a rice cooker which finishes boiling rice without unevenness irrespective of the quantity of the amount of boiled rice and takes visual delicious efficacy by making flat the upper surface of the boiled rice after finishing boiling. <P>SOLUTION: The rice cooker comprises a pot 2, a heating means 4, a pressure valve 14 having an opening/closing mechanism 18 which opens/closes communication with the inside of the pot 2 and the open air so that the air in the pot 2 is approximately constant, a pressure valve opening mechanism 17 for forcibly opening the valve 14, and a control means 20, which controls the heating amount of the heating means 4 and performs the control of the open actuation of the valve 14 by the valve open mechanism 17. The control means 20 boils rice after a water absorbing process for causing rice to absorb water to a water content of 20-30.5%, changes the pressure within the pot by opening the valve by the valve opening mechanism at least once during boiling, and agitates the rice by a bumping phenomenon in a condition that the amount of the remaining water within the pot is much irrespective of the amount of the boiled rice. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pressure-type rice cooker that cooks delicious rice in a short time by cooking rice in a pressurized state.
[0002]
[Prior art]
In rice cooking using a pressure rice cooker, a water absorption step in which water is absorbed into rice in a pot, a rising heating step in which the temperature is heated and heated to a boiling state with full power after water absorption, and a pressurized pot. In general, the rice is cooked through a boiling maintaining step in which rice is cooked while maintaining the boiling state, and a rice shaving step in which the rice is washed after the boiling maintaining step.
[0003]
One of the great features of rice cooked by the pressure rice cooker is that during cooking, especially before boiling or during boiling, the pressure in the pot is increased, and the synergistic effect of heating and pressure allows water to penetrate into rice grains in a short time. It is about shortening rice cooking time and, as a result, cooking soft rice. Such a pressure cooker is disclosed in, for example, Patent Documents 1 and 2.
[0004]
[Patent Document 1]
JP-A-6-22710
[Patent Document 2]
JP 2001-137113 A
[0005]
[Problems to be solved by the invention]
In recent rice cookers, what is called an IH rice cooker, which generates heat by eddy current generated by an induction heating coil that heats a pot containing water and rice and heats it, has a main structure in which the pot itself generates heat. Therefore, rice in the area near the inner wall of the pot was sufficiently heated, but rice in the center from the center to the upper part of the pot, which was far from the inner wall, was insufficiently heated, causing uneven cooking. .
[0006]
Looking at the state of the rice cooked by such a rice cooker, the rice existing around the center of the pot or the center of the upper part (the center of the cooked rice upper surface) is insufficiently heated. It is not swelled as much, and the shape of the top of the rice seen when the lid is opened is not a flat surface, but a dish shape with a lower upper center and a higher upper periphery (near the inner wall of the pot), Lacked a delicious effect.
In addition, the rice in the upper central part, which was not sufficiently heated, had a core remaining and lacked in taste.
[0007]
On the other hand, a hot plate type rice cooker which is a method different from the IH rice cooker and in which a hot plate with a built-in heater which has been commercialized for a long time is closely adhered to the bottom of the pan is to heat the entire bottom of the pan with the heater. However, intensive heating of the bottom of the pot causes uneven cooking in the pot, and the cooked rice upper surface becomes mountain-shaped when cooked, and the whole is not cooked uniformly.
[0008]
Therefore, an object of the present invention is to provide a rice cooker that can cook rice evenly, and can provide a visual delicious effect by making the upper surface of the cooked rice flat. .
In particular, when the amount of cooked rice was large, uneven cooking was likely to occur, and it was difficult for the cooked rice top surface to be flat, but the cooked rice top surface was flattened even if the cooked rice amount was large or small. It aims to provide a rice cooker.
[0009]
[Means for Solving the Problems]
Another invention made in order to solve the above-mentioned problem is a pot for storing cooked rice containing water and rice, heating means for heating the cooked rice in the pan, and a lid closing an opening of the pot. A pressure valve having an opening / closing mechanism for communicating or shutting off the inside of the pot and the outside air so that the pressure in the pot is substantially constant; and a pressure provided on the pressure valve for forcibly opening the pressure valve. A valve opening mechanism and control means for controlling the amount of heating of the heating means and controlling the opening operation of the pressure valve by the pressure valve opening mechanism, the control means keeping the cooked rice below the gelatinization temperature of rice A water absorption step of absorbing water into the rice so that the water content of the rice is 20 to 30.5% while controlling the heating means, a heating step of raising the temperature until the cooked rice is brought to a boiling state, The cooked rice is maintained in a boiling state, and the pressure is released by a pressure valve opening mechanism while the boiling state is maintained. At least 1 KaiHiraki actuates the valve so as to control to sequentially perform a boiling maintained steps so as to change the pressure within the pot.
[0010]
Here, the water content R of rice is defined as follows.
R = (B + C) / (A + B + C)
A: Weight of components other than water contained in natural rice
B: Weight of water contained in natural rice
C: Weight of absorbed water
[0011]
According to this, when rice to be cooked containing water and rice is put in a pot, the lid is closed, and when rice cooking is started, heating control by the heating means is started. After the water absorption time for the rice to absorb water (water absorption step), the temperature of the cooked rice is rapidly raised to a boiling state (start-up heating step). The opening and closing mechanism performs the opening and closing operation so that the pressure in the pan becomes substantially constant in the pressurized state (boiling maintaining step). The control means opens the pressure valve opening mechanism when the inside of the pan is brought into a boiling state, and forcibly opens the opening and closing mechanism of the pressure valve. When the pressure in the pot changes rapidly due to this operation, a vigorous boiling phenomenon (bumping) occurs due to the pressure drop in the pot, and the rice grains are vigorously stirred by the bubbles generated by this boiling phenomenon. Thus, the rice grains in the center of the pot and the rice grains near the inner wall of the pot are mixed.
[0012]
At this time, the water absorption of the rice in the water absorption step is limited so that the water content of the rice at the end of the water absorption step is 30.5% or less to increase the residual water in the pot. Further, by absorbing water so that the water content of the rice is at least 20% or more, rice is prevented from leaving rice with a wick remaining after cooking. The start-up heating step is started such that the water content of rice in the water absorption step is in the range of 20% to 30.5%. Therefore, when boiling starts, a large amount of water is present in the pot, so that rice easily moves in the pot. In this state, the rice is vigorously stirred by opening the pressure valve by the pressure valve opening mechanism and reducing the pressure at a stretch to cause bumping.
As a result of such stirring, the mixture is stirred in the pot, and the heating is entirely averaged. As a result, uneven cooking is eliminated, and the shape of the cooked rice upper surface can be made flat.
[0013]
In the water absorption step, the control means preferably sets the water absorption time and the water temperature based on the correlation between the water temperature, the water absorption time and the water content of rice.
An optimum water temperature and water absorption time can be easily determined in advance so as to obtain a desired water content based on an experimentally obtained correlation.
[0014]
It is preferable that the control means immediately open the pressure valve by the pressure valve opening mechanism so that the pressure in the pot becomes close to the atmospheric pressure immediately after the transition from the start-up heating step to the boiling maintaining step.
Not only does the amount of water absorbed by the rice increase with time, but also as the boiling begins, it becomes steam over time and the water decreases, so the first time immediately after the transition to the boiling maintenance process, which is the time when the amount of water is the largest in the boiling maintenance process, Perform pressure change operation. Further, at this time, the greater the pressure fluctuation difference of the pressure in the pot, the more intense the agitation.
[0015]
The pressure valve opening / closing mechanism maintains the pressure in the pan at 1.10 to 2.20 atm during the boiling maintaining process and when the pressure valve is not forcibly opened by the pressure valve opening mechanism. It is preferable to form it as follows. By setting the pressure in the pot to this range, stirring by bumping can be sufficiently performed. The pressure can be further increased if only the use of bumping is considered, but other factors such as the pressure resistance of the rice cooker also pose a problem, so that the above range is preferable.
[0016]
Preferably, the control means forcibly opens the pressure valve opening mechanism three to six times during the boiling maintaining step. If the remaining water is sufficient, the stirring effect increases as the number of times increases, but the amount of remaining water decreases with time, so even if the number of times increases, the stirring effect weakens in the latter half, so set to about 3 to 6 times Good to do.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment)
Hereinafter, a rice cooker according to an embodiment of the present invention will be described.
FIG. 1 is a flowchart showing the outline of the rice cooking process by the rice cooker according to the embodiment of the present invention (the three rice cooking courses of “brown rice / normal rice cooking course”, “white rice / normal rice cooking course”, and “white rice / sushi rice cooking course”). 2 is a partial cross-sectional view of the rice cooker (shows a partial cross-sectional view of a lid, a pressure valve, and a pressure valve opening mechanism), and FIG. 3 is a partially enlarged cross-sectional view of FIG. 2 (a pressure valve and a pressure). 4 shows a more detailed flowchart of the "white rice / normal rice cooking course" of the flowchart shown in FIG. 1, FIG. 5 is a flowchart following the flowchart shown in FIG. 4, and FIG. 6 is FIG. 3 is a characteristic diagram of the "white rice / standard (normal) rice cooking course" shown in FIG. FIG. 7 is a diagram showing the relationship between the water content of rice at the end of the water absorption step and water supply time and water temperature, FIG. 8 is a diagram showing the shape of the cooked rice top surface, and FIG. 9 is a taste evaluation test by a sensory test It is a figure showing a result.
[0018]
The function of the rice cooker according to the present embodiment will be described based on the flowchart shown in FIG.
Cooking rice basically includes a water absorption step of absorbing water at a gelatinization temperature or lower (for example, 55 degrees), a startup heating step of heating water and rice by full heating (full power), and a boiling maintaining step of maintaining a boiling state. The following steps are sequentially performed: a boiling step 1 performed after the end of boiling maintenance, an additional cooking step performed after the finishing of the boiling step 1, and a drying step 2 performing finishing of the spots.
[0019]
Cooking rice is performed not only for white rice but also for brown rice. In general, brown rice has a low water absorption because bran is not removed. On the other hand, white rice has less bran and good water absorption. Therefore, when cooking brown rice, it is necessary to absorb water more easily than when cooking white rice as a standard (normal) rice.
Therefore, in rice cooking of brown rice, rice is cooked in such a manner that the pressure in the pot is kept as high as possible from the beginning of rice cooking as compared with rice cooking of white rice.
[0020]
On the other hand, in rice cooking of white rice, there are a case where white rice is cooked from white rice (referred to as standard rice for white rice) and a case where rice for sushi and pilaf is cooked (applied rice for white rice). When cooking rice for sushi and pilaf instead of white rice from rice, it is necessary to reduce the amount of water adhering to the periphery of the rice grains after cooking as compared to cooking white rice. For this reason, when cooking rice for sushi and pilaf, rice is cooked from the start-up heating step to the boiling maintenance step by setting the pressure as close to the atmospheric pressure as possible (in a state where water is hardly absorbed) instead of pressurizing the rice. It is necessary to reduce water absorption.
[0021]
As described above, in the rice cooking, the optimal rice cooking conditions are slightly different depending on the content of the rice (white rice or brown rice, white rice, sushi rice, pilaf, etc.). Therefore, as shown in FIG. There is a selectable rice cooking course. In the rice cooker according to the present embodiment, three rice cookers, a brown rice / standard rice cooker course A, a white rice / standard rice cooker course B, and a white rice / applied rice cooker course C, are provided. A course is provided so that the user can select one of the courses.
[0022]
Among the three courses, the “brown rice / standard (normal) rice cooking course A” is preferably a process in which the brown rice absorbs as much water as possible from the start-up heating step to the boiling maintenance step. Is designed to close the pressure valve as much as possible to prolong the pressurized state.
On the other hand, in the “white rice / applied (sushi) rice cooking course C”, since the amount of water absorbed into the white rice needs to be reduced as described above, the pressure valve should be opened as much as possible between the start-up heating step and the boiling maintaining step. I have to.
Therefore, the present invention is implemented in “white rice / standard (normal) rice cooking course B” which is other than the above rice cooking course among the three rice cooking courses.
Therefore, the flow according to the present invention will be described with reference to "white rice / standard (ordinary) rice cooking course B" and "flow of brown rice / standard (normal) rice cooking course A" and "white rice / applied (sushi sushi) rice cooking course C" will be described. Description is omitted.
[0023]
First, the structure of the rice cooker will be described. 2 and 3, (1) is a rice cooker main body, (2) is a pot made of aluminum and stainless steel clad material for storing water and rice, and (3) is a case for storing the pot (2), and an outer wall. Is provided with a heating means (4) using an induction coil together with the outer bottom wall (the outer bottom wall is not shown).
[0024]
(5) is an openable and closable cover for covering the opening (6) of the pan (2), which comprises a removable inner cover (7) provided on the lower side and an outer cover (8) provided above the inner cover (7). Is done.
[0025]
The inner lid (7) has a valve seat (10) having a valve hole (9), and a metal ball (10) placed on the valve seat (10) so as to close the valve hole (9) by its own weight. 11) and a pressure valve (14) comprising a cover (12) for covering the ball (11). The pressure valve (14) moves the ball (11) on or off the valve hole (9) depending on the balance between the pressure in the pan (2) and the weight of the ball (11). ) Opens and closes the valve hole (9) by such movement.
Therefore, the opening / closing mechanism (18) of the pressure valve (14) is formed by the valve hole (9), the valve seat (10), the ball (11), and the cover (12).
[0026]
Also, a safety valve (13) is provided that opens when the pressure in the pot (2) is abnormally pressurized (for example, when the pressure valve (14) fails and does not open during cooking) and releases the pressure in the pot. I have.
[0027]
A plunger (17) is attached to the pressure valve (14) in the outer lid (8). The plunger (17) is controlled by the control means (20). That is, when the plunger (17) is in a normal state in which the output from the control means (20) is not received, the rod (17a) projects from the cylinder (17b) to release the ball (11) on the valve hole (9). Push laterally through hole (9) to forcibly open valve hole (9). When the output of the control means (20) is received by the plunger (17), the rod (17a) is immersed in the cylinder (17b). At this time, the ball (11) returns onto the valve hole (9) by its own weight and closes the valve hole (9).
In this way, the plunger (17) operates as a pressure valve opening mechanism, and the pressure valve and the pressure valve opening mechanism are pressure changing means for forcibly reducing the pressure in the pot pressurized during the rice cooking process. Used as
[0028]
Further, the outer lid (8) has a steam port (15) for communicating the inside of the pot (2) with the atmosphere through a valve hole (9) and releasing the pressure and steam in the pot (2) to the atmosphere. are doing.
[0029]
Further, the rice cooker main body (1) includes a selection means (16) for selecting a rice cooking course.
The control means (20) is composed of hardware including a CPU, a ROM, a RAM, and the like, and software for executing the contents of a flowchart described later, as is well known.
[0030]
Although not shown, a temperature sensor for detecting the temperature of the pot bottom is attached to the pot bottom, and a steam sensor for detecting the steam temperature is attached to an appropriate position on the lid (8). It is configured to be sent to
Although not shown, the control means (20) has a built-in clock functioning as various timers, and monitors various elapsed times required in the rice cooking process.
[0031]
In the rice cooker of this embodiment, when the "white rice / normal rice cooking course" is selected (S101 to S103), as shown in the flowcharts of FIGS. 1, 4, and 5, and the characteristic diagram of FIG. Heating is started by 4) (S104), and at the same time, the water absorption step is executed (S106) while the pressure valve (14) is kept open (S105).
Along with the execution of the water absorption step, a water absorption timer (not shown) starts measuring the water absorption time (T1 = 10 minutes) (S107), and at the same time, measures the pot bottom temperature (K1) by a temperature sensor (not shown) ( S108).
[0032]
At this time, the water absorption time (T1) of 10 minutes and the pot bottom temperature (K1) of 55 ° C. (° C.) are defined as the water absorption time at which the water content of rice at the end of the water absorption step is in the range of 20% to 30.5%. This is a value obtained by experimentally determining the pan bottom temperature (water temperature) in advance.
For example, the water absorption condition for not more than 30.5%, which is the upper limit of the water content of rice, is determined from the following measurement data.
Fig. 7 shows the water content of several rices of different rice types (brands) and oldness when the water temperature (corresponding to the pot bottom temperature) is 55 degrees and the water absorption time is set to 10 minutes or 15 minutes. Is measured data. As shown in this data, regardless of the type and age of the rice, if the water absorption time is 10 minutes, the water content of the rice will be 28% to 30.5%. If the water absorption time is set to 15 minutes, the water content of the rice is increased from 31% to 34%. From this, regardless of the type of rice, if the water absorption time is 10 minutes at a water temperature of 55 ° C., the water content can be reduced to 30.5% or less.
[0033]
The water temperature (pot bottom temperature) and the water absorption time for setting the water content of rice to 20% or more, which is the lower limit, can be determined from the same measurement data.
As described above, in the present embodiment, the water temperature (pot bottom temperature) (K1) is set to 55 degrees, and the water absorption time (T1) is set to 10 minutes.
[0034]
When the water absorption time (T1) reaches 10 minutes (S111), heating is performed with the entire heating amount (S112). At the same time, the rod (17a) of the plunger (17) is pulled into the cylinder (17b), the ball (11) is placed on the valve hole (9) by its own weight, the valve hole (9) is closed, and the pressure in the pot is reduced. (S113) (start-up heating step).
[0035]
Then, the steam temperature (K2) is measured (S114). Then, heating is continued until a steam temperature (K2) of 75 degrees is detected. The measurement temperature of 75 degrees by the steam sensor is the temperature of the steam when it is determined that boiling starts under the pressurized condition by the ball (11) at the position where the steam sensor is currently attached.
When it is detected that the steam temperature has reached 75 degrees (S115), the process proceeds to a boiling maintaining step in which boiling starts in the pot (2) (S116) (boiling maintaining step).
[0036]
Immediately after shifting to the boiling maintaining step, the amount of heating is controlled, and the first opening operation of the pressure valve (14) by the plunger (17) is performed (S117).
Next, the heating is stopped (S118), and it is waited that the forcible opening operation of the pressure valve (14) continues for 4 seconds, so that the pressure in the pot decreases to near the atmospheric pressure. (S119).
As a result, the pressure in the pot is reduced to a value near the atmospheric pressure at once, and a vigorous boiling state (bumping) is generated. The generated bubbles agitate the rice grains.
[0037]
The opening time is set to 4 seconds, and this time is obtained by calculating the time during which the pressure can be returned to the atmospheric pressure and the stirring can be performed with the maximum boiling energy. That is, if it is 2 to 4 seconds, the pressure does not return to the atmospheric pressure, so that some boiling energy remains. The opening time may be extended for 4 seconds or more, but if it is too long, problems such as spillage tend to occur. Therefore, the opening time is preferably about 2 to 6 seconds. In this way, at least the initial stirring (when the amount of residual water is the largest and the stirring effect can be expected the most), the stirring is performed more vigorously by greatly changing the pressure from the pressurized state to the vicinity of the atmospheric pressure.
[0038]
After the initial stirring, the rod (17a) of the plunger (17) is pulled in so that the pressure valve (14) does not open (S120), heating is started (S121), and the elapse of 28 seconds is awaited (S120). S122). 28 seconds is a time until the pressure in the pot is sufficiently recovered and the next stirring can be performed, and the optimum time is experimentally obtained in advance.
[0039]
It is preferable that the pressure in the pot is maintained at 1.10 to 2.20 atm when the pressure valve is not forcibly opened by the plunger. By setting the pressure in the pot to this range, stirring by the bumping phenomenon can be sufficiently performed. The pressure can be further increased if only the use of the bumping phenomenon is considered. However, other factors such as the pressure resistance of the rice cooker also pose a problem, so the above range is preferable.
[0040]
After the elapse of 28 seconds, it is confirmed whether or not the number of opening and closing of the pressure valve is the predetermined number of times (S133). If the number of opening / closing is up to five times, the process returns to S116 to execute the forcible opening operation of the pressure valve again, and the steps from S116 to S122 are repeated. The opening and closing of the pressure valve is repeated until the number of opening and closing of the pressure valve becomes six (S133).
[0041]
In this embodiment, when the pressure valve is opened and closed six times, the opening time of the pressure valve is set to 4 seconds in all cases. Therefore, the opening time may be adjusted according to the number of times. For example, the opening operation time may be lengthened each time the number of times increases, such as the second and third times.
[0042]
The pressure fluctuation in the pot at this time is shown in FIG. That is, in the boiling maintaining step, six severe pressure drops occur in response to the forced opening of the pressure valve performed six times.
[0043]
The number of times the pressure valve (14) is forcibly opened during the boiling maintaining step can be obtained at least once to obtain the effect, but is preferably 3 to 6 times. If the amount of residual water in the pot is sufficient, the stirring effect will increase as the number of opening operations increases more than six times, but the amount of residual water during the boiling maintaining process will decrease with time. At most, in the latter half of the boiling maintaining step, the amount of residual water is small, the movement of rice in the pot is difficult, and the stirring effect is weak even if forced opening operation is performed. Therefore, it is preferable to set the opening operation to be performed about 3 to 6 times at the beginning of the boiling maintaining step.
[0044]
After the sixth pressure change operation, the rod (17a) of the plunger (17) is retracted into the cylinder (17b) to prevent the pressure valve (14) from opening (S134). Then, the control of the heating amount is continued (S135), the boiling maintaining step is continued, and it is detected that the pot bottom temperature (K3) reaches 130 degrees (S136).
The pot bottom temperature of 130 ° C. is a temperature at which it is determined that the water in the boiling pot has withered, a forced dry-up has been performed, and the dry-up has ended.
When the pan bottom temperature (K3) reaches 130 degrees (S137), the heating is stopped (S138), and the process proceeds to the spotting process 1.
[0045]
When the process shifts to the muraling step 1, the timing of the muraling time (T2 = 4 minutes) is started, and the opening of the pressure valve (14) by the plunger (17) is prevented until the lapse of 4 minutes (S139). .
Note that the optimum time experimentally obtained in advance is used for the spotting time and the additional cooking time described later.
[0046]
After 4 minutes (S140), the pressure valve (14) is opened by the plunger (17) (S141), the process proceeds to the additional cooking process, and the reheating time (T3 = 3 minutes) is counted. Is started (S142).
When the reheating time (T3) finishes measuring the time of 3 minutes (S143), the process proceeds to the muraling step 2 and starts measuring the muraling time (T4 = 6 minutes) (S144). When the time measurement for 6 minutes is completed (S145), the rice cooking is finished (S146), and the process proceeds to the warming step (S147).
[0047]
Through the above steps, rice can be cooked in such a manner that the rice is sufficiently stirred in the pot by stirring using the bumping phenomenon, regardless of the amount of cooked rice.
[0048]
(Reference example)
In order to verify the effect of stirring due to the bumping phenomenon when cooking rice in the flow of the above-described embodiment, a comparison was made with a reference example described below, and the results will be described.
[0049]
In the flow of the above-described embodiment, the water content of the rice is limited from 20% to 30.5% in the water absorption step, so that the residual water amount is increased at the end of the water absorption step, and the water amount in the pot at the start of the subsequent boiling maintaining step. The rice is cooked in a state where a large amount of rice is left. However, in the flow of the reference example, the rice is sufficiently absorbed in the water absorption step so that the water content at the end of the water absorption step becomes 31% or more (in the pot). (The amount of water is reduced by the amount of water absorbed by the rice.)
[0050]
Therefore, in the flow of the reference example, specifically, the point that the standby time (S111) in the water absorption step is 15 minutes is different from the standby time (10 minutes) of the flow of the above-described embodiment.
[0051]
FIG. 8 shows the shape of the top surface of the cooked rice. In the figure, the left column (a) is a rice shape based on conventional rice cooking (cooking without pressure change operation), the central column (b) is a rice shape according to the flow of the reference example, and the right column (c) is a rice rice shape according to the present embodiment. The rice is shaped by flow, and the upper row is for cooking 3 cups of rice and the lower row is for cooking 5.5 cups of rice.
In the conventional rice cooking method, the upper surface of the rice is dish-shaped regardless of the amount of rice cooked. In the case of rice cooked in the reference example (referred to as “dance cooked rice 1”), the top surface of the rice is flat when three cups are used, but slightly dish-shaped when 5.5 cups are used. In the cooked rice of the present embodiment (referred to as “dance cook 2”), the cooked rice is flat regardless of the amount of cooked rice.
[0052]
FIG. 9 shows taste evaluation test data obtained by the sensory test.
The taste evaluation test data evaluates six items of gloss, fragrance, taste, stickiness, softness, and preference. Evaluation criteria for each of these items, gloss, fragrance, taste, it is preferable that the score is higher, preference for stickiness and softness, moderate stickiness, softness is desired, generally, It is considered that the stickiness is preferably about 3.8 to 3.9, and the softness is preferably 3.0 to 3.2.
[0053]
The upper data in FIG. 9 shows the taste evaluation (gloss, aroma) of the conventional rice cooker (no agitation) and the rice cooker (dancing rice cooker 2) according to the embodiment of the present invention when water is absorbed at a water temperature (immersion temperature) of 55 degrees in the water absorption step. , Taste, stickiness, softness, and taste). In this case, according to the evaluation criteria described above, the rice cooker according to the embodiment of the present invention was all superior.
[0054]
The middle data in FIG. 9 shows the rice cooked by the reference example (Odori-Nikki 1) (in the case of water absorption at 55 ° C. for 15 minutes (water content at the end of the water absorption step is 31% or more)) and in the embodiment of the present invention. It is the data which compared with the rice cooked by (Round rice cooker 2) (water absorption for 10 minutes at the immersion temperature of 55 degrees C. (water content at the end of the water absorption step is within 20% to 30.5%)). Also in this case, according to the above evaluation criteria, the rice cooked according to the embodiment of the present invention was all excellent evaluation.
[0055]
Further, the lower data in FIG. 9 is data comparing the case where the amount of cooked rice is 1 go (1 cup) and the case of 5 go (5 cups) in the cooked rice (dance cook 2) of the embodiment of the present invention. In this case, according to the evaluation criteria described above, there is no significant difference between 1-cooked rice (1 cup) and 5-cooked rice (5 cups), and there is no effect of the amount of cooked rice in this embodiment. I understand.
[0056]
From the above, it can be seen from the taste evaluation test data that the conventional rice cooker, the rice cooker according to the reference example (dance cooker 1), and the rice cooker according to the embodiment of the present invention (dance cooker 2) are more delicious in this order. It was also found that according to the embodiment of the present invention, regardless of the amount of cooked rice, uneven cooking was eliminated by the stirring effect and delicious rice was obtained.
[0057]
(Modification)
In the embodiment as described above, the heating means (4) is not limited to the IH heating method of heating by the eddy current generated by the induction coil, but may be a method in which a heating plate with a built-in heater is attached to the bottom of the pot or other heating methods. In short, a heating method capable of controlling heating may be used.
[0058]
The pressure valve may be of any type as long as it has an opening / closing function that automatically opens when the pressure is equal to or higher than the set pressure and automatically closes when the pressure is equal to or lower than the set pressure. Further, the pressure valve opening mechanism for forcibly opening the opening / closing mechanism of the pressure valve is a mechanism that works mechanically as long as the valve can be forcibly opened from the state where the pressure valve is closed. Alternatively, a mechanism that operates electromagnetically may be used.
[0059]
【The invention's effect】
As described above, according to the present invention, water absorption is performed such that rice absorbs water so that the water content of the rice becomes 20 to 30.5% while controlling the heating means so as to maintain the cooked rice at a temperature below the gelatinization temperature of the rice. Since the process is performed and the process proceeds to the start-up heating process and the boiling maintenance process, it is possible to keep the water in the pot as much as possible and bring it into a boiling state, and to open the pressure valve to generate bumping phenomenon. The rice is easy to move and can be stirred vigorously.
[0060]
Then, the rice grains at the center side move to the side in the pot without stirring, and the rice grains at the center side are moved to the side in the pot, as a result, sufficient heat is applied to the whole rice grains and uniform heating is performed, The upper surface of the rice becomes flat.
In particular, in the present invention, the bumping phenomenon can be generated in a state where the amount of residual water is large, so that the rice can be stirred even when the amount of cooked rice is large.
[Brief description of the drawings]
FIG. 1 is a main part flowchart showing a rice cooking process by a rice cooker according to one embodiment of the present invention.
FIG. 2 is a partial cross-sectional view including a lid, a pressure valve, and a pressure valve opening mechanism of the rice cooker according to one embodiment of the present invention.
FIG. 3 is a partially enlarged sectional view of a pressure valve and a pressure valve opening mechanism in FIG. 2;
FIG. 4 is a detailed flowchart of the “white rice / normal rice cooking course” in the flowchart shown in FIG. 1;
FIG. 5 is a flowchart following the flowchart shown in FIG. 4;
FIG. 6 is a characteristic diagram of the “white rice / normal rice cooking course” shown in FIG. 1;
FIG. 7 is a diagram showing the water content of rice after the water absorption step.
FIG. 8 is a diagram showing the shape of the cooked rice upper surface.
FIG. 9 is a view showing taste evaluation test data.
[Explanation of symbols]
1 Rice cooker body
2 pots
4 heating means
5 Lid
9 Valve hole
10 Valve seat
11 balls
12 Cover
13 Safety valve
14 Pressure valve
16 Selection means
17 plunger (pressure valve opening mechanism)
18 Opening / closing mechanism
20 control means

Claims (6)

A pot for storing the cooked rice containing water and rice, a heating means for heating the cooked rice in the pot, a lid for closing the opening of the pot, and a pot for keeping the pressure in the pot substantially constant. A pressure valve having an opening / closing mechanism for communicating or shutting off the inside and outside air, a pressure valve opening mechanism attached to the pressure valve for forcibly opening the pressure valve, and controlling a heating amount of the heating means. Control means for controlling the opening operation of the pressure valve by the pressure valve opening mechanism,
The control means controls the heating means so as to maintain the cooked rice at a temperature below the gelatinization temperature of the rice, and absorbs water so that the water content of the rice becomes 20 to 30.5%. During the start-up heating step of raising the temperature until the food is brought to a boiling state, while maintaining the cooked food in a boiling state, the pressure valve is opened at least once by a pressure valve opening mechanism during the boiling to reduce the pressure in the pot. A rice cooker characterized by being controlled so as to sequentially execute a changed boiling maintaining step. 2. The rice cooker according to claim 1, wherein in the water absorption step, the control means sets the water absorption time and the water temperature based on a correlation between the water temperature, the water absorption time and the water content of the rice. In claim 1, the control means opens the pressure valve by the pressure valve opening mechanism immediately after the start-up heating step shifts to the boiling maintaining step, so that the pressure in the pot becomes close to the atmospheric pressure. Rice cooker. In claim 1, the pressure in the pot is maintained at 1.10 to 2.20 atm during the boiling maintaining step and when the pressure valve is not forcibly opened by the pressure valve opening mechanism. A rice cooker characterized by being formed so as to be cooked. The rice cooker according to claim 1, wherein the control means controls the pressure in the pot by changing the pressure in the pot by forcibly opening the pressure valve by a pressure valve opening mechanism three to six times during the boiling maintaining step. . A pot containing the cooked rice containing water and rice, a heating means for heating the cooked rice, a lid closing the opening of the pot, and the pressure in the pot being set to a substantially constant predetermined pressure. A rice cooking method using a rice cooker having a pressure valve having an opening / closing mechanism for communicating or shutting off the inside of the pot and the outside air, and sealing the inside of the pot with a lid to cook rice,
(A) a water absorption step of accommodating cooked rice in a pot, maintaining the temperature at or below the gelatinization temperature of the rice, and absorbing water so that the water content of the rice is 20% to 30.5%;
(B) a rising heating step in which the cooked rice is heated so as to boil;
(C) maintaining the cooked rice in a boiling state and, during the maintaining of the boiling state, opening the pressure valve at least once by a pressure valve opening mechanism to change the pressure in the pot, and a boiling maintaining step. A rice cooking method characterized by performing.

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