JP4596979B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker, and more particularly to a rice cooker equipped with a brown rice rice cooking menu that can cook brown rice deliciously in a short time.

  Most of the staple rice is white rice. The reason for this is that white rice has a shining color similar to silver, commonly known as “Ginshari”, has good taste and aroma, and has good digestion and absorption characteristics. However, this white rice is obtained by removing the pericarp, seed coat, paste layer, germ, etc. covering the surface of brown rice at the time of milling, the protein contained in this pericarp, seed coat, paste layer, germ, etc. Most of nutrients such as lipids, vitamin B1, dietary fiber, and minerals are removed, and the nutritional balance is significantly reduced.

  In recent years, a variety of foods are available and the eating habits of individuals who eat them are diversifying. On the other hand, as health consciousness has increased remarkably, it has been reconsidered to eat without removing the nutrients contained in brown rice in line with this trend. Is coming to be. However, since the surface of this brown rice is covered with germs, pericarp that protects endosperm, and seed coat, it is significantly less water-absorbing than white rice, and when cooked in the same way as white rice, it is hard and can withstand food. It is not a thing, but can be finally eaten by cooking over time using a pressure cooker or a pressure rice cooker (for example, refer to the following patent document 1).

  FIG. 10 is a temperature change curve diagram showing the brown rice cooking process of the rice cooker described in Patent Document 1 below.

  This rice cooker has a water absorption step I for absorbing a predetermined amount of water in the brown rice in the pan, and a so-called medium-puff step II for heating the cooked rice consisting of the absorbed brown rice and water to a boil, Brown rice is cooked through a rice cooking process consisting of a boiling maintenance process III for maintaining the cooked rice in a boiling state and a steaming process IV for steaming the cooked rice after the boiling maintenance process.

In the water absorption process I, the cooked rice composed of brown rice and water is heated through a plurality of preheating processes 1 to 3, and water is absorbed into the brown rice over a predetermined time. This preheating time is longer than the rice porridge cooking process, and it is about 30 minutes only in each preheating process 1-3. Thereafter, the water absorption time is further increased because the water is absorbed even in the middle patch process.
JP-A-8-457 (FIG. 6, FIG. 9, paragraph [0021]) JP 11-313623 A (Claims (Claim 1), paragraph [0013])

  By the way, the brown rice using the rice cooker described in the above-mentioned Patent Document 1 gradually increases the water absorption temperature to a predetermined value through three stages of preheating, that is, preheating 1 to preheating 3, in the water absorption process I, and is relatively long. It takes about 30 minutes to make brown rice absorb water, and it is cooked over a long period of time in the subsequent steps of the soup and boiling maintenance process. For this reason, when this rice cooking time is totaled, it usually takes about 90 minutes with this type of rice cooker. Also, since brown rice has poor water absorption efficiency, it is difficult to adjust the amount of water, and if the amount of water and the water absorption time are not selected to be the optimum value in relation to the amount of cooked rice, the taste of the cooked brown rice will not be uniform. Uneven taste will occur.

  The reason why the water absorption efficiency is poor is that the surface of brown rice is covered with a peel, a seed coat, a paste powder layer, etc., and this peel prevents the water from entering the rice core. Therefore, if the pericarp and seed coat can be broken, water penetrates into the inside from the torn part and the cooking is promoted, and the endosperm, pericarp and seed coat are softened and swollen to cook a soft cooked rice such as white rice. be able to. Therefore, as a method for breaking such pericarp and seed coat, for example, a method of irradiating brown rice with infrared rays having a specific wavelength is known (for example, see Patent Document 2). However, this method requires a device that irradiates brown rice with a special infrared ray, and such a device cannot be mounted on a rice cooker used in a general household. At the present time, brown rice that has broken such pericarp and seed coat is not widespread and is not easily available to general users.

  Then, this invention was made | formed in order to solve the subject of such a prior art, and the objective of this invention is the rice cooker provided with the brown rice rice cooking menu which can cook brown rice deliciously in a short time. It is to provide.

In order to achieve the above object, a rice cooker according to claim 1 of the present application is a heating means for heating a pot into which a rice to be cooked is put, an opening in which the pot is accommodated, and a rice to be cooked in the pot. A rice cooker body having a lid, a lid that closes the opening of the rice cooker body, a pressure valve that is attached to the lid and adjusts the internal pressure in the pan, and a pressure valve opening mechanism that controls the pressure valve A selection means for selecting various rice cooking menus, a rising heating process for heating the cooked food in the pan until boiling according to the rice cooking menu selected by the selection means, and the rising heating process. In a rice cooker equipped with a control device that performs a predetermined rice cooking process including a boiling maintenance process for maintaining the cooked rice in a boiling state,
Wherein the control device, when the brown rice cooking menu from the cooking menu is selected by the selection unit starts the cooking process from the start-up heating step, Oite the boiling maintain step, the pressure valve opening mechanism The pressure valve is controlled to open and close multiple times, and the pressure valve is controlled to open and close a plurality of times, and the depressurization from the pressurized state by the steam in the pan to the vicinity of atmospheric pressure and the pressure increase from the vicinity of the atmospheric pressure by steam are repeated alternately. It is characterized by making it.

  The invention according to claim 2 of the present application is the rice cooker according to claim 1, wherein the opening / closing control of the pressure valve by the control device is an initial stage of transition from the start-up heating process to the boiling maintenance process. It is characterized by being concentrated on.

  Moreover, invention of Claim 3 of this application is a rice cooker of Claim 1, The opening / closing control of the said pressure valve by the said control apparatus is changed according to the quantity of the to-be-cooked rice in the said pan. It is characterized by that.

  Further, the invention according to claim 4 of the present application is the rice cooker according to any one of claims 1 to 3, wherein the opening / closing control of the pressure valve by the control device includes opening in several seconds and closing in several seconds. It is performed by repeating.

  Moreover, invention of Claim 5 of this application is the rice cooker of Claim 1, When the said control apparatus is a pressurization state, the pressure in the said pan is 1.05-2.0 atmospheres. It is characterized by controlling to become.

  Moreover, invention of Claim 6 of this application is the rice cooker of Claim 2, The said control apparatus is the pressurization state after the said initial stage in the internal pressure in the pressurization state in the said pan of the said initial stage. It is characterized by controlling so as to be higher than the internal pressure at.

  By providing the above configuration, the present invention has the following excellent effects. That is, according to the invention of claim 1, during the brown rice rice cooking menu, when the inside of the pan is depressurized from the pressurized state to the atmospheric pressure, it becomes a bumping and boiling state, and the cooked rice is vigorously stirred. Due to this vigorous stirring, the brown rice grains rub against each other and collide with each other, the skin and seed coat covering the surface of the brown rice grains are damaged and broken, and hot water penetrates into the core of the brown rice from the damaged and broken parts. So that you can cook delicious brown rice with elasticity and sweetness. Also, during this brown rice cooking menu, the rice to be cooked is agitated vigorously, and the skin and seed coat covering the surface of the brown rice grain are damaged and absorbed, and water is absorbed from this part. The time required can be reduced, and the cooking time can be shortened as a whole.

  According to the invention of claim 2, since the control device concentrates on opening and closing of the pressure valve in the initial stage of shifting from the start-up superheating process to the boiling maintenance process, damage / destruction of brown rice grain peels, seed coats, etc. Since it is performed at the initial stage of rice cooking, the penetration of hot water into brown rice becomes faster.

  According to the invention of claim 3, by changing the open / close control of the pressure valve according to the amount of the cooked rice, for example, when there are many cooked rice in the pan, the number of times of the open / close control of the pressure valve is increased, On the other hand, when there are few items to be cooked, it is possible to perform optimal pressure valve opening / closing control depending on the amount of rice to be cooked by reducing the number of times of pressure valve opening / closing control, and the efficiency according to the amount of rice cooked Can realize a good rice cooking process.

  According to the invention of claim 4, since the opening and closing of the pressure valve is repeated opening and closing in units of several seconds and closing in units of several seconds, the bumping phenomenon in the pan is repeated violently, and stirring of the cooked rice is efficiently and effectively performed. Done.

  According to invention of Claim 5, by maintaining the pressurization pressure by the vapor | steam in a pot at 1.05-2.0 atmospheres, ensuring the safety at the time of a boiling maintenance process, to-be-cooked rice in a pot. Stir efficiently. If the pressure in the pan is increased to a high pressure, that is, close to 2.0 atm, the bumping state when the pressure valve is opened becomes more intense, and if this bumping state is intense, the skin covering the surface of the brown rice grain, Since damage and destruction of the seed coat and the like can be performed satisfactorily, it is preferable to increase the pressure to 2.0 atm in the pressure valve control performed in the initial stage of the boiling maintenance process. In addition, when damaging or destroying the pericarp, seed coat, etc. of brown rice grains, it is preferable to increase the pressure in the pan to about 2.0 atmospheres. By maintaining the pressure state, the rice can be cooked more deliciously.

  According to invention of Claim 6, the pan accompanying the opening and closing of the pressure valve of an initial stage is made by making the internal pressure in the pressurization state in the initial stage pan which shifted to the boiling maintenance process higher than the internal pressure in the pressurization state after that. Since the pressure difference in the inside becomes large and the bumping phenomenon in the pot becomes intense, the pericarp and seed coat of brown rice grains can be damaged and destroyed efficiently in a short time.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment shown below exemplifies a rice cooker for embodying the technical idea of the present invention, and is not intended to specify the present invention for this rice cooker. Other embodiments within the scope are equally applicable.

  1 is a front view of a rice cooker according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view in which an outer case of the rice cooker in FIG. 1 is omitted, and FIG. 3 is an enlarged sectional view of a pressure valve release mechanism portion in FIG. 4 is a block diagram constituting the control device, FIG. 5 is a characteristic diagram showing temperature / pressure changes in the white rice / standard rice cooking course, FIG. 6 is a characteristic diagram showing temperature / pressure changes in the brown rice rice cooking course, FIG. 7, FIG. 8 and 9 are flowcharts of the rice cooking process for executing the rice cooking menu.

As shown in FIG. 1 and FIG. 2, the rice cooker 1 has a pan 7 into which the rice to be cooked is put, an opening in which the pan 7 is accommodated in the upper portion, and the pot 7 inside to heat the cooked rice. A rice cooker main body (hereinafter referred to as a main body) 2 having heating means 5 for heating, and a lid body 10 having a locking mechanism pivotally supported on one side of the main body 2 to cover the opening and lock in a closed state; A pressure valve 13 that is attached to the lid 10 and adjusts the internal pressure in the pan 7, a pressure valve opening mechanism 18 that controls the pressure valve, a display operation unit 30 that displays and selects various rice cooking menus, A water absorption step of controlling the heating means 5 and the pressure valve opening mechanism 18 in accordance with the selected rice cooking menu, heating the cooked rice in the pan to a predetermined temperature, and allowing the cooked rice to absorb a predetermined amount of moisture over a predetermined time. , Heating up the heated cooked rice until boiling Step comprises boiling maintained step of maintaining the object to be rice was in boiling state, and a control unit 24 for executing step steaming cook by steam to be rice product after the boiling step of maintaining sequentially a.

  Here, first, the structure and control device of the rice cooker will be described first.

As shown in FIGS. 1 and 2, the main body 2 includes a box-shaped outer case 3 with a bottom and an inner case 4 that is accommodated in the outer case and in which the pan 7 is accommodated. A gap is formed between the inner case 4 and a control circuit board or the like (not shown) constituting the control device 24 is disposed in the gap. The inner case 4 is provided with a heating means 5 at the bottom 4a and side 4b, and a pan bottom temperature sensor 6 comprising a thermistor for detecting the pan bottom temperature at the bottom 4a. As the heating means 5, an electromagnetic induction coil wound in a donut shape is used.

  As shown in FIG. 1, the main body 2 is provided with a display operation unit 30 including a display panel for displaying various rice cooking menus on the front surface 3 a and operation buttons for selecting the rice cooking menu.

  As shown in FIG. 2, the pan 7 is a relatively deep bottom container into which a predetermined amount of cooked rice made of water and rice is put, and is made of a clad material of aluminum and stainless steel.

  As shown in FIG. 2, the lid 10 includes an inner lid 11 that closes the opening of the pan 7, an outer lid 12 that closes the entire opening of the main body 2, and the like. One end of the lid 10 is pivotally supported by one end of the main body 2, and the other end is locked to the other end of the main body by a locking mechanism.

  In the upper part of the inner lid 11, a pressure valve 13 and a pressure valve opening mechanism 18 for opening the pressure valve are provided. As shown in FIG. 3, the pressure valve 13 includes a valve seat 15 in which a valve hole 14 having a predetermined diameter is formed, a metal ball 16 placed on the valve seat 15 so as to close the valve hole 14, The cover 17 is configured to restrict the movement of the ball 16 and hold the ball 16 on the valve seat 15. The pressure valve opening mechanism 18 is attached to a cylinder 19a around which an electromagnetic coil is wound, a plunger 19b that slides in the cylinder 19a by excitation of the electromagnetic coil to move the ball 16, and a tip of the plunger. It consists of a spring and an operating rod 20.

  The pressure valve opening mechanism 18 is controlled by the control device 24. That is, when the electromagnetic coil is excited based on a command from the control device 24, the plunger 19b jumps out of the cylinder 19a and collides with the ball 16, and pushes the ball 16 in the lateral direction. By this extrusion, the ball 16 is moved from above the valve hole 14 to forcibly open the valve hole 14. Further, in this open state, when the excitation to the electromagnetic coil is stopped, the plunger 19b is pulled back into the cylinder 19a by a spring force, and this pull back eliminates the force that the plunger 19b pushes the ball 16 in the lateral direction. The ball 16 returns to the valve hole 14 and the valve hole 14 is closed by the ball 16.

  The outer lid 12 is provided with a steam port 21 that communicates the space between the inner lid 11 and the outer lid 12 and the atmosphere. Further, the inner lid 11 is provided with a safety valve 22 for releasing the steam in the pan to the outside through the steam port 21 when the pressure in the pan rises to an abnormal pressure of a predetermined value or more. In addition, a steam temperature sensor 23 (see FIG. 3) is attached to the inner lid 7.

  Next, the configuration of the control device 24 will be described with reference to FIG. The control device 24 includes a device main body 25 that controls the rice cooking process provided in the rice cooker 1. The apparatus main body 25 is connected to a plurality of operation buttons including a menu key, a start key, a reservation key, the heating means 5, the display panel, the pressure valve release mechanism 18, and various sensors. Further, in the apparatus main body 25, a CPU for performing various processes, a ROM and a RAM for storing various data, a rice cooking menu detection means for detecting a selected rice cooking menu, and a pressure valve 13 are provided. Controls a valve opening / closing timer in which an opening / closing time is set, a counter for counting the number of times the pressure valve 13 is opened, a heating control means for controlling the heating temperature and heating time of the rice cooker 1, and a display screen displayed on the display panel Display panel control means, and pressure valve opening mechanism driving means for controlling the opening / closing timing of the pressure valve 13 by driving the pressure valve opening mechanism 18.

  And the control apparatus 24 performs various control in the rice cooking process based on the input signal input with a some operation button by providing said structure.

  The rice cooker 1 has at least two rice cooking menus: a white rice / standard rice cooking menu and a brown rice rice cooking menu.

As shown in FIG. 5, the white rice / standard rice cooking menu includes a water absorption process I _{0 in} which a predetermined amount of water is absorbed by the white rice grains below the gelatinization temperature, and a cooked rice consisting of water and white rice grains after the water absorption process. Performed by a rising heating process I ₁ for raising the temperature to the boiling temperature, a boiling maintaining process I ₂ for maintaining the cooked rice in a boiling state for a predetermined time, and a steaming process I ₃ for steaming the cooked rice after the boiling maintenance is completed. Is done. The steaming process is divided into the first steaming process 1, the additional cooking process performed after the completion of the steaming process 1, and the second steaming process 2 (steaming process for finishing) performed after the additional cooking process. Is called.

In addition, as shown in FIG. 6, the brown rice cooking menu has a rising heating step I ₁ for heating and heating the cooked rice consisting of brown rice and water to a boiling temperature, and maintaining the cooked rice in a boiling state for a predetermined time. boiling sustain step I ₂ of is performed by steaming step I ₃ cook by steam to be rice product after the boiling maintained terminated. The steaming process is divided into the first steaming process 1, the additional cooking process performed after the completion of the steaming process 1, and the second steaming process 2 (steaming process for finishing) performed after the additional cooking process. Is called.

In the boiling-preserving process I _2, the temperature in the pot increases, and the pressure of Nabenai predetermined value, for example, when a predetermined time has elapsed reaches 1.2 atm, a pressure valve opening mechanism 18 by the controller 24 The pressure valve 13 is opened by actuating, and the pressure in the boiling pan is reduced to near atmospheric pressure all at once. This opening is continued for several seconds, and then the pressure valve is closed again to increase the pressure in the pan from the atmospheric pressure, and the pressure valve 13 is repeatedly opened and closed several times, for example, 10 times or more, and the inside of the pan is bumped and boiled. And stir the cooked rice violently.

  By opening and closing the pressure valve, the brown rice grains are vigorously stirred and stirred in the pan. By this agitation, the brown rice grains are rubbed against each other, and the pericarp and seed coat covering the surface of the brown rice grains by colliding with each other are damaged and broken. Since the brown rice grains in which the pericarp and seed coat are damaged and broken are easily penetrated by hot water from this portion, water absorption into the core portion of the brown rice is promoted. After that, similarly to the standard rice cooking process, the cooked brown rice is performed through the boiling maintenance process and the steaming process.

According to this brown rice rice cooking menu, the water absorption process I ₀ in the white rice / standard rice cooking menu is omitted, and water absorption and rice cooking are performed simultaneously in the boiling maintenance process I ₂ , so the rice cooking time required for the rice cooking process is about 90 minutes from the conventional about 90 minutes. It was confirmed by experiment that it can be shortened to about a minute. Moreover, water adjustment became easy, and delicious brown rice cooked with elasticity and sweetness was made.

  Next, the rice cooking process of these rice cooking menus will be described with reference to the drawings. First, with reference to FIG.2, FIG7 and FIG.8, the rice cooking process which performs a white rice and a standard rice cooking menu is demonstrated.

  First, at the start of rice cooking, the pan 7 into which a predetermined amount of water and white rice has been charged by the user is accommodated in the inner case 4 and the lid 10 is closed (S101). Next, a rice cooking menu is selected by the display operation unit 30 (S102). Here, when the standard rice cooking menu is selected (S103), a high frequency current is applied to the heating means 5 attached to the outer bottom wall and the outer wall of the inner case 4, and an eddy current is generated in the pan 7, which is the pan. Is heated and heating of the cooked rice is started (S104a).

Then, by operating the pressure valve opening mechanism 18 moved the ball 16, is forced to open position the pressure valve 13 (S105a), the water absorption step _{I 0} is executed by the control unit 24 (S 106 a). When the water absorption step _{I 0} is started, water timer (not shown) starts counting the water time T1 (S107a), and then the pan bottom temperature K1 is measured by the pan bottom temperature sensor 6 (S108a). The measurement of the pan bottom temperature K1 is performed until it reaches a predetermined temperature. When it is confirmed that the pan bottom temperature has reached a predetermined value, for example, 55 ° C. (S109a), the heating amount of the heating means 5 is controlled by the control device 24. The water absorption time is measured while keeping the cooked rice at a predetermined temperature (S110a). This water step I ₀ is continued preset water time T1, for example, 10 minutes.

Set water time T1 (10 min) has elapsed (S111a), the process proceeds to start-up heating step _{I 1} (S112a). In the start-up heating step I ₁ , the heating means 5 is fully heated (full power heating) so as to be in a boiling state in a short time, and the pressure valve opening mechanism 18 is operated by the control device 24 to pull back the plunger 19 a. Then, the pressure valve 13 is closed by the ball 16. That is, the ball 16 rolls onto the valve hole 14 due to its own weight, closes the valve hole 14, and closes the pressure valve 14 (S113a). In this state, the pressure in the pan 7 is increased until the pressure rises to a pressure value at which the ball 16 can be pushed up through the valve hole 14. Therefore, the pressure of the steam in the pan at this time can be appropriately determined by setting the weight of the ball 16 and the size of the valve hole 14.

In the start-up heating step _{I 1,} the steam temperature K2 is measured by the steam temperature sensor 23 (S114a). And this steam temperature K2 is a predetermined temperature, for example 75 and ℃ reaches (S115a), the rice product is the temperature at which the boiling phenomenon, rising heating step I ₁ is completed. The vapor pressure at this time is controlled by the pressure valve 13 and becomes a predetermined pressure equal to or higher than atmospheric pressure, for example, about 1.2 atmospheric pressure. Then, as shown in FIG. 8, the boiling maintained Step _{I 2} is started (S116).

After shifting to the boiling hold step I _2, the pressure in the pot 7 is a predetermined pressure above atmospheric pressure, for example, about 1.2 atm, so that the rice was boiled with saturated temperature corresponding to this pressure.

Also, when entering the boiling hold step I _2, forced opening operation of the pressure valve 13 is performed by moving the ball 16 actuates the pressure valve opening mechanism 18 by immediately controller 24 (S117). During this opening operation, heating of the heating means 5 is stopped (S118), and the forced opening operation of the pressure valve 13 is continued for a predetermined time, for example, 4 seconds (S119). The forced opening operation of the pressure valve 13 reduces the pressure in the pan 7 to near atmospheric pressure.

In this way the boiling maintain process I _2, lowering the pressure in the pot 7 from a given boiling pressure (about 1.2 atm) to stretch near atmospheric pressure, the pan 7 becomes violent bumping state. In this bumping state, bubbles are generated in the pan, and the cooked rice is stirred by the bubbles. As a result, the cooked rice is heated uniformly and cooked.

  The predetermined time for forcibly opening the pressure valve 13 is set to such a time that the pressure in the pan 7 returns to substantially atmospheric pressure (ie, about 4 seconds) by the first forcible opening operation of the pressure valve 13. Yes. By setting the time for forcibly opening the pressure valve 13 to atmospheric pressure in this way, the maximum agitation energy can be obtained. Further, after the pressure valve 13 is forcibly opened for the predetermined time (4 seconds), the pressure valve opening mechanism 18 is operated to close the pressure valve again (S120), and the pressure valve 13 is heated again for a predetermined time, for example, 28 seconds. (S121, S122). In addition, this heating time (28 seconds) is time required for the pressure in the pan 7 to recover to the aforementioned predetermined pressure (about 1.2 atmospheres). This time is obtained experimentally in advance.

The forced opening of the pressure valve 13 by the pressure valve opening mechanism is repeated a plurality of times, for example, six times (S133). In addition, if time passes in the boiling process shown to (S121) and (S122), the residual water amount in the pan 7 will decrease, a pressure fluctuation range will become small, and a bumping phenomenon will become weak. Therefore, forced opening of the pressure valve 13 is the focus in the early stages of boiling maintained Step I ₂ effectively.

  When the operation of opening the pressure valve 13 a plurality of times is finished, the forced opening of the pressure valve 13 by the pressure valve opening mechanism 18 is stopped, and the pressure valve 13 is closed (S134). And the heating by the heating means 5 is continued (S135), and the pan bottom temperature K3 is measured (S136). Then, when the pan bottom temperature K3 reaches a predetermined temperature, for example, 130 ° C. (S137), it is determined that the water in the pan 7 has dried up and the forced dry-up has ended, so the heating action by the heating means 5 is stopped (S138). .

Subsequently, start the steaming step _{I 3,} first steaming is shifted to step 1, steaming starts counting the time T2 (S139). When the predetermined steaming time T2 elapses for a predetermined time, for example, 4 minutes (S140), the pressure valve opening mechanism 18 forcibly opens the pressure valve 13 (S141), and the process proceeds to the additional cooking step. If it enters into this additional cooking process, while reheating with the heating means 5, the water adhering to the surface of rice will be evaporated, and the additional cooking (reheating) time T3 will be measured (S142). And when predetermined | prescribed additional cooking time T3, for example, 3 minutes , (S143) passes, the heating operation by the heating means 5 will be stopped, it will transfer to the steaming process 2, and the steaming time T4 will be timed (S144). When the steaming time T4 elapses for a predetermined time, for example, 5 minutes (S145), the rice cooking is finished (S146), the process proceeds to the heat retaining process (S147), and the standard rice cooking process is finished.

  Next, with reference to FIG.2, FIG7 and FIG.9, the rice cooking process which performs a brown rice rice cooking menu is demonstrated.

At the start of cooking, the user first stores the pan 2 containing a predetermined amount of water and brown rice in the case 4 and closes the lid 10 (S101). Next, a rice cooking course is selected by the display operation unit 30 (S102). Here, when brown rice rice menu is selected (S103), together with the cooking object is heated (S104b) by the heating means 4 performs full power heating by Immediately rising heating step _{I 1} is started (S112b ). When the start-up heating step I ₁ is started, the pressure valve 13 is closed by the ball 16 by operating the pressure valve opening mechanism 18 by the control device 24 and pulling back the plunger 19a. That is, the ball 16 rolls onto the valve hole 14 due to its own weight, closes the valve hole 14, and closes the pressure valve 14 (S113b). In this state, the pressure in the pan 7 is increased until the pressure rises to a pressure at which the ball 16 can be pushed up through the valve hole 14. Therefore, the pressure in the pan at this time can be determined as appropriate by setting the weight of the ball 16 and the size of the valve hole 14.

Further, in the start-up heating step _{I 1,} the steam temperature K2 is measured by the steam temperature sensor 23 (S114b). And this steam temperature K2 is a predetermined temperature, for example KA (refer to FIG. 6) ° C. is reached, (S115b), the rice product is the temperature at which the boiling phenomenon, rising heating step I ₁ is completed. The pressure in the pan at this time is controlled by the pressure valve 13 and becomes a predetermined pressure equal to or higher than atmospheric pressure, for example, about 1.2 atm. Then, the boiling maintained Step _{I 2} is started (S151).

After shifting to the boiling hold step I _2, as shown in FIG. 9, the predetermined pressure steam pressure above atmospheric pressure within the pot 7, i.e. is about 1.2 atm, the rice was saturated temperature corresponding to the steam pressure It begins to boil at.

Also, when entering the boiling hold step I _2, forced opening operation of the pressure valve 13 is performed by moving the ball 16 actuates the pressure valve opening mechanism 18 by immediately controller 24 (S152). At the same time, the timing by the valve opening / closing timer is started (S153), and during the opening operation, heating of the heating means 5 is stopped (S154), and the forced opening operation of the pressure valve 13 is performed for a predetermined time, For example, it continues for 4 seconds (S155). This opening time is monitored by a valve opening / closing timer. By this forced opening operation, the pressure in the pan 7 is reduced to near atmospheric pressure.

Thus, lowering the pressure in the pot 7 from a given boiling pressure (about 1.2 atm) to stretch near atmospheric pressure at the boiling maintained Step I _2, in the pot 7 becomes violent bumping state. In this bumping state, bubbles are generated in the pan, and the cooked rice is stirred by the bubbles. Due to this vigorous stirring, the brown rice grains are rubbed against each other and collide with each other, the peel and seed coat covering the surface of the brown rice grains are damaged and broken, and hot water penetrates into the core of the brown rice from the damaged and broken parts. Water is absorbed. Moreover, there is also an effect that the cooked rice is uniformly heated and cooked by stirring in the bumping state.

The predetermined time for forcibly opening the pressure valve 13 is set to such a time that the pressure in the pan 7 returns to substantially atmospheric pressure (ie, about 4 seconds) by the first forcible opening operation of the pressure valve 13. Yes. By setting the time for forcibly opening the pressure valve 13 in this way, the maximum agitation energy can be obtained. In addition, after the pressure valve 13 is forcibly opened for the predetermined time (4 seconds), the pressure valve opening mechanism 18 is operated to close the pressure valve again (S156), and the pressure valve 13 is heated again for a predetermined time, for example, 28 seconds. (S157, S158). This heating time (28 seconds) is a time required for the steam pressure in the pan 7 to recover to the above-mentioned predetermined pressure (about 1.2 atm). Also, this time is determined in advance by experiments.

The forcible opening of the pressure valve 13 by the pressure valve opening mechanism is counted by a counter, and the counter is incremented every time the timer counts a predetermined time (4 seconds) (S159). Then, the series of processes (S152) to (S159) are performed until the count of the counter reaches a predetermined number of times, for example, 12 (S160). In addition, when time passes in the reboiling process shown to (S157) and (S158), the amount of residual water in the pan 7 will decrease, a pressure fluctuation range will become small, and a bumping phenomenon will become weak. Therefore, forced opening of the pressure valve 13 is the focus in the early stages of boiling maintained Step I ₂ effectively. Moreover, the upper limit (12 times in this embodiment) of the counter number when this brown rice cooking menu is selected is larger than that in the case of the white rice / standard rice cooking menu. This is to make sure the skin and seed coats covering the surface of the brown rice grain are scratched. And at the time of rice cooking menu selection, no water absorption step I ₀ of rice-standard cooking menu, because the water to brown rice is carried out after the scratches are formed on the pericarp and testa by bumping boiling maintained Step I ₂ is rice, It is longer than the standard rice menu.

  When the operation of opening the pressure valve 13 a plurality of times is finished, the forced opening of the pressure valve 13 by the pressure valve opening mechanism 18 is stopped. And the heating by the heating means 5 is continued (S161), and the pan bottom temperature K3 is measured (S162). Then, when the pan bottom temperature K3 reaches a predetermined temperature, for example, KB (see FIG. 6) ° C. (S163), it is determined that the water in the pan 7 has dried up and the forced dry-up has been completed. Stop (S164).

Its description will in the subsequent steaming step I ₃ is the same as in the case of white rice-standard cooking menu will be omitted.

  In this embodiment, the internal pressure in the pressurized state in the pan was set to 1.2 atm. However, the internal pressure may be increased to near 2.0 atm, or the pan in the initial stage that shifted to the boiling maintenance step. The internal pressure in the pressurized state may be 2.0 atmospheres, and the internal pressure in the subsequent pressurized state may be 1.2 atmospheres. As a result, the pressure difference in the pan increases with the opening and closing of the pressure valve in the initial stage of the boiling maintenance process, the bumping phenomenon in the pan becomes intense, and damage and destruction of the brown rice grain skin and seed coat are efficiently performed in a short time. It can be carried out. Moreover, in the said Example, although the opening / closing frequency | count of the pressure valve was set to 12, it is preferable to change according to the amount of rice cooking. For example, when the amount of cooked rice is large, the number of times of opening and closing the pressure valve is large, and when the amount is small, the number of cooked rice can be cooked more efficiently by reducing the number of times.

  As shown above, according to the brown rice rice cooking menu in the rice cooker of the present invention, the water absorption process in the white rice / standard rice cooking menu is eliminated, the rice cooking process can be shortened as a whole, the rice cooking time is shortened, and water adjustment is easy. You can cook delicious brown rice.

FIG. 1 is a front view of a rice cooker according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view in which the outer case of the rice cooker in FIG. 1 is omitted. 3 is an enlarged cross-sectional view of the pressure valve release mechanism portion of FIG. FIG. 4 is a block diagram constituting the control device, FIG. 5 is a characteristic diagram showing changes in temperature and pressure in white rice / standard rice cooking course, FIG. 6 is a characteristic diagram showing temperature and pressure changes in the brown rice cooking course, FIG. 7 is a flowchart of the rice cooking process for executing the rice cooking menu. FIG. 8 is a flowchart of the rice cooking process for executing the rice cooking menu. FIG. 9 is a flowchart of the rice cooking process for executing the rice cooking menu. FIG. 10 is a temperature change curve diagram showing a brown rice cooking process of a conventional rice cooker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rice cooker 2 Main body 3 Box-shaped outer case 3a Front wall 4 Inner case 5 Heating means 6 Pan bottom temperature sensor 7 Pan 10 Lid body 11 Inner lid 12 Outer lid 13 Pressure valve 14 Valve hole 15 Valve seat 16 Ball 17 Cover 18 Pressure valve Opening mechanism 19a Cylinder 19b Plunger 20 Operating rod 21 Steam port 22 Safety valve 24 Control device 25 (Control device) Main body 30 Display operation section

Claims (6)

A pan into which the cooked rice is put, an opening in which the pan is accommodated, and a rice cooker body having heating means for heating the cooked rice in the pan, and a lid for closing the opening of the cooker body, A pressure valve attached to the lid for adjusting the internal pressure in the pan, a pressure valve opening mechanism for controlling the pressure valve, selection means for selecting various rice cooking menus, and a rice cooking menu selected by the selection means In accordance with the above, the predetermined cooking step including the rising heating step of heating the cooked rice in the pan until boiling and the boiling maintaining step of maintaining the cooked rice in a boiling state following the rising heating step is performed. In a rice cooker equipped with a control device,
Wherein the control device, when the brown rice cooking menu from the cooking menu is selected by the selection unit starts the cooking process from the start-up heating step, Oite the boiling maintain step, the pressure valve opening mechanism The pressure valve is controlled to open and close multiple times, and the pressure valve is controlled to open and close a plurality of times, and the depressurization from the pressurized state by the steam in the pan to the vicinity of atmospheric pressure and the pressure increase from the vicinity of the atmospheric pressure by steam are repeated alternately. Rice cooker, characterized by 2. The rice cooker according to claim 1, wherein the opening / closing control of the pressure valve by the controller is concentrated in an initial stage of transition from the start-up heating process to the boiling maintenance process. 2. The rice cooker according to claim 1, wherein the opening / closing control of the pressure valve by the control device is changed according to the amount of cooked rice in the pan. The rice cooker according to any one of claims 1 to 3, wherein the opening / closing control of the pressure valve by the control device is performed by repeatedly opening and closing in units of seconds and closing in units of seconds. The said control apparatus is controlled so that the pressure in the said pan may be 1.05-2.0 atmospheres when it is in a pressurization state, The rice cooker of Claim 1 characterized by the above-mentioned. The said control apparatus controls the internal pressure in the pressurization state in the said pan in the said initial stage so that it may become higher than the internal pressure in the pressurization state after the said initial stage.

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