JP2012110686A - Rice cooker and method for determining deterioration level of rice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker capable of determining the deterioration level of rice without boiling water for rice cooking, and to provide a method for determining the deterioration level of rice.SOLUTION: The rice cooker includes: an inner pot for housing rice and water together; a heating part for heating the inner pot arranged outside of the inner pot; a stirring blade for stirring the rice in the inner pot; a turbidity sensor 13 arranged in the inner pot for measuring the turbidity of the water inside the inner pot; a motor control part 31 for causing the stirring blade to stir the rice in the inner pot; and a determination part 20 for determining the deterioration level of the rice in the inner pot after the rice in the inner pot is stirred, based on the turbidity measured by the turbidity sensor 13.

Description

  The present invention relates to a rice cooker having a function of stirring rice and a method for determining the degree of deterioration of rice for determining the degree of deterioration of rice.

  In order to cook rice optimally, it is necessary to have an appropriate washing rice and an appropriate rice cooking sequence according to the condition of the rice.

  What is the ideal rice washing method? One of the commonly used procedures is to “dispose of the water in which rice is first soaked”. This is said to be because the rice bran component remaining on the rice surface is absorbed together with water and re-adsorbed on the rice. However, in reality, it is understood that there is no difference in the amount of residual rice cake between the case where the water poured in the first time is immediately discarded and the rice is washed from the second time and the case of washing from the first water. Yes. In addition, it is often thought that it is better to completely remove rice cake, but most of the nutrition of rice, such as vitamins and minerals, is contained in rice cake. You can taste it. Even in the manufacture of wash-free rice, a method has been developed to leave the rice cake.

  Conventionally, as a rice washing machine, there is one described in Japanese Utility Model Laid-Open No. 5-5022 (Patent Document 1). In this conventional rice washing machine, the turbidity of the rice washing wastewater is detected, and when this turbidity becomes lower than the set value, the rice washing is stopped. For this reason, in the said conventional rice washing machine, rice washing is performed until the turbidity of the rice washing wastewater becomes below a certain value.

  However, the accuracy of current milled rice is high, and most of the milled rice bran has been removed at the time of milling, and the white component of the washed rice is mainly starchy.

  Therefore, since the conventional rice washing machine performs the washing of rice until the turbidity of the washing wastewater becomes a certain value or less, there is a high possibility that the rice will be washed more than necessary.

  In addition, the higher the freshness of rice, the more likely it is that starch will flow out of the rice by washing the rice.

  Therefore, if the rice washing is performed until the turbidity of the rice washing wastewater is not more than a certain value as in the conventional rice washing machine, new rice may be washed excessively and old rice may become insufficient.

  What is the proper washing time for rice? This depends on the degree of rice degradation. As mentioned above, it is better to finish the washing time in about 30 seconds in order to leave the rice cake. However, old rice has a strong old rice odor and is yellowed, so if you leave the rice cake in the washed rice for about 30 seconds, the smell will be strong and it will be a yellow rice with a delicious taste. Therefore, in the case of old rice, it is necessary to wash the rice for a longer time than new rice in order to improve the taste.

  Therefore, in order to cook rice optimally, it is necessary to change the rice washing time according to the degree of rice degradation.

  Conventional rice cookers that can determine the degree of deterioration of rice include those described in Japanese Patent Application Laid-Open No. 7-111940 (Patent Document 2). This conventional rice cooker determines whether the rice during the rice cooking operation is new rice or old rice, and performs control based on this determination. More specifically, in the conventional rice cooker described above, the frequency of the plosive sound of the rice that is generated when boiling the cooked water is different depending on the degree of deterioration of the rice, and the plosive sound is detected with a microphone. Is a new rice, or whether the rice is an old rice.

  However, in the above-described conventional rice cooker, the degree of deterioration of rice during cooking cannot be determined unless the cooked water is boiled and a popping sound of rice is produced.

  Therefore, the conventional rice cooker has a problem that the degree of deterioration of rice cannot be determined unless boiling rice water is boiled.

Japanese Utility Model Publication No. 5-5022 Japanese Patent Laid-Open No. 7-11940

  Then, the subject of this invention is providing the rice cooker which can determine the deterioration degree of rice, and the deterioration degree determination method of rice, without boiling rice cooking water.

In order to solve the above problems, the rice cooker of the present invention is
A turbidity of water in which rice is soaked is measured, and a deterioration degree determination mechanism for determining the degree of deterioration of the rice based on the turbidity is provided.

  According to the above configuration, the deterioration degree determination mechanism measures the turbidity of the water in which the rice is soaked, and determines the deterioration degree of the rice based on this turbidity. Can determine the degree of deterioration of rice.

The rice cooker of one embodiment is
An inner pot that houses rice with water,
A heating unit arranged outside the inner pot and for heating the inner pot;
It is arranged in the inner pot and comprises a stirring body for stirring the rice in the inner pot,
The deterioration degree determination mechanism is
A turbidity sensor that is arranged in the inner pot or in the inner pot periphery, and measures the turbidity of water in the inner pot,
A deterioration degree determination unit that determines the deterioration degree of rice in the inner pot based on the turbidity measured by the turbidity sensor;

  According to the above embodiment, since the degree of deterioration of the rice in the inner pot is determined based on the turbidity measured by the turbidity sensor, even if the water in the inner pot, that is, the rice cooking water is not boiled, The degree of deterioration can be determined.

  Moreover, if the time which stirs rice is changed according to the deterioration degree of the said rice, it can also prevent that the washing rice becomes excessive or becomes insufficient.

  Moreover, since the deterioration degree of rice can be determined without boiling the cooked rice water, appropriate heating control can be performed before and after boiling the cooked water.

In the rice cooker of one embodiment,
The determination of the degree of deterioration of rice by the deterioration degree determination unit is performed within 1 minute after the start of washing of rice by stirring of the stirring body.

  According to the above embodiment, the determination of the deterioration degree of the rice by the deterioration degree determination unit is performed within 1 minute after the start of the rice washing by stirring of the stirring body, so that the accuracy of determining the deterioration degree of rice can be improved. it can.

The rice cooker of one embodiment is
The rice washing time and the rice cooking sequence corresponding to the degree of deterioration of the rice determined by the deterioration determining unit are automatically selected.

  According to the said embodiment, since the rice washing time and rice cooking sequence (for example, rice cooking time) according to the said deterioration degree are selected automatically, the user does not set the rice washing time and rice cooking sequence (for example, rice cooking time). Can cook rice optimally.

The rice cooker of one embodiment is
Excess determination means for determining whether or not the degree of deterioration of rice determined by the deterioration determination unit is greater than a preset value;
When it is determined by the excess determination means that the degree of deterioration of the rice is greater than a preset value, the low temperature from the start of rice cooking to just before the heating of the heating unit starts Low temperature keep period stirring means for stirring the rice with the stirring body in the keep period.

  According to the embodiment, the excess determination means determines whether or not the degree of rice deterioration determined by the deterioration determination unit is greater than a preset value. At this time, if the excess determination means determines that the degree of deterioration of the rice is greater than a preset value, the low temperature from the start of rice cooking until just before the heating of the heating unit starts During the keep period, the low temperature keep period stirring means stirs the rice with a stirring body, so that the amount of solid components eluted from the rice can be increased. As a result, it is possible to prevent the rice obtained from the rice from becoming a hard texture.

The rice cooker of one embodiment is
Water temperature maintaining means for maintaining the temperature of the water in which the rice is soaked at 60 ° C. by heating of the heating unit, according to the degree of deterioration of the rice,
The time becomes longer as the degree of deterioration of the rice increases.

  According to the said embodiment, the said water temperature maintenance means maintains the temperature of the water in which the rice is soaked at 60 degreeC with the heating of a heating part for the time according to the deterioration degree of rice. At this time, the time becomes longer as the degree of deterioration of the rice increases, so that the amount of glucose, which is a sweet component, can be increased in the rice. Moreover, the stickiness of the rice obtained from the said rice can also be increased.

The rice cooker of one embodiment is
A rotation drive device for rotating the stirring body is provided.

  According to the said embodiment, when the said rotational drive device rotationally drives a stirring body, rice is fully stirred and sufficient rice washing can be performed.

In the rice cooker of one embodiment,
The turbidity sensor includes a light source and a light receiving unit that receives light caused by the light source.

  According to the above embodiment, the turbidity sensor has a light source and a light receiving unit that receives light originating from the light source, so the turbidity of water in the inner pot is determined based on the output signal of the light receiving unit. Can be sought.

The method for determining the degree of deterioration of rice of the present invention is as follows:
A turbidity measurement process for measuring the turbidity of water soaked with rice,
A deterioration degree determination step for determining the degree of rice deterioration based on the turbidity measured in the turbidity measurement step.

  According to the said structure, first, the turbidity of the water which soaked rice is measured by the said turbidity measurement process. Next, the deterioration degree of rice is determined based on the turbidity measured in the turbidity measurement process by the deterioration degree determination process. Therefore, the degree of deterioration of rice can be determined without boiling the water, that is, the cooked rice water.

A method for determining the degree of deterioration of rice according to one embodiment, comprising a stirring step of stirring rice immersed in water,
The turbidity measurement step is performed after the rice is stirred in the stirring step.

  According to the embodiment, when the rice soaked in water is first stirred by the stirring step, the water is suspended. Next, the turbidity of water in which rice is soaked is measured by the turbidity measurement step. Next, based on the turbidity of the water, the degree of deterioration of the rice soaked in the water is determined. Therefore, the degree of deterioration of rice can be determined without boiling the water, that is, the cooked rice water.

  Further, if the time for stirring the rice is changed according to the degree of deterioration of the rice, it is possible to prevent the washing rice from becoming excessive or insufficient.

  Moreover, since the deterioration degree of rice can be determined without boiling the cooked rice water, appropriate heating control can be performed before and after boiling the cooked water.

  In addition, since the turbidity measurement step is performed after the rice is stirred in the stirring step, the degree of rice deterioration is determined based on the turbidity of the water suspended in the stirring step. Accuracy can be increased.

In order to solve the above problems, the rice cooker of the present invention is
An inner pot that houses rice with water,
A heating unit arranged outside the inner pot and for heating the inner pot;
An agitator that is disposed in the inner pot and stirs the rice in the inner pot;
A turbidity sensor that is arranged in the inner pot or in the inner pot periphery, and measures the turbidity of water in the inner pot,
A deterioration degree determination unit for determining the deterioration degree of rice in the inner pot based on the turbidity measured by the turbidity sensor.

  According to the above configuration, since the degree of deterioration of the rice in the inner pot is determined based on the turbidity measured by the turbidity sensor, the deterioration of the rice can be achieved without boiling the water in the inner pot, that is, the cooked water. Degree can be determined.

  Moreover, if the time which stirs rice is changed according to the deterioration degree of the said rice, it can also prevent that the washing rice becomes excessive or becomes insufficient.

  Moreover, since the deterioration degree of rice can be determined without boiling the cooked rice water, appropriate heating control can be performed before and after boiling the cooked water.

The rice cooker of one embodiment is
The rice washing time and the rice cooking time corresponding to the degree of deterioration of the rice determined by the deterioration determining unit are automatically selected.

  According to the said embodiment, since the rice washing time and rice cooking time according to the said deterioration degree are selected automatically, even if a user does not set rice washing time and rice cooking time, it can cook rice optimally. it can.

The rice cooker of one embodiment is
A rotation drive device for rotating the stirring body is provided.

  According to the said embodiment, when the said rotational drive device rotationally drives a stirring body, rice is fully stirred and sufficient rice washing can be performed.

In the rice cooker of one embodiment,
The turbidity sensor includes a light source and a light receiving unit that receives light caused by the light source.

  According to the above embodiment, the turbidity sensor has a light source and a light receiving unit that receives light originating from the light source, so the turbidity of water in the inner pot is determined based on the output signal of the light receiving unit. Can be sought.

The method for determining the degree of deterioration of rice of the present invention is as follows:
An agitation process for agitating rice soaked in water;
After the rice is stirred in the stirring step, a turbidity measuring step for measuring the turbidity of the water,
A deterioration degree determination step of determining the deterioration degree of the rice based on the turbidity measured in the turbidity measurement step.

  According to the above configuration, first, when the rice soaked in water is stirred in the stirring step, the water is suspended. Next, the turbidity of water in which rice is soaked is measured by the turbidity measurement step. Next, based on the turbidity of the water, the degree of deterioration of the rice soaked in the water is determined. Therefore, the degree of deterioration of rice can be determined without boiling the water, that is, the cooked rice water.

  Further, if the time for stirring the rice is changed according to the degree of deterioration of the rice, it is possible to prevent the washing rice from becoming excessive or insufficient.

  Moreover, since the deterioration degree of rice can be determined without boiling the cooked rice water, appropriate heating control can be performed before and after boiling the cooked water.

  As chemical changes during the conversion to old rice, (1) increased hydrophobicity due to the increase in disulfide bonds in the protein, (2) gelatinization is suppressed by the binding of fatty acids and starch produced by the degradation of lipids, etc. Are known. These changes predict that the rate of starch spillage when washing old rice will be slower than that of new rice, and using three types of rice with different storage periods at high temperatures, turbidity 1 minute after the start of washing Was measured. As a result, it was found that the longer the storage period, the lower the turbidity. The present invention makes it possible to easily determine the degree of deterioration of rice by utilizing such properties and detecting the turbidity during automatic rice washing.

  According to the rice cooker of the present invention, since the turbidity of the water in which the rice is soaked is measured and the deterioration degree determination mechanism for judging the degree of deterioration of the rice is provided based on this turbidity, the water in which the rice is soaked Even if (cooked water) is not boiled, the degree of deterioration of rice can be determined.

  According to the method for determining the degree of degradation of rice according to the present invention, based on the turbidity measurement step for measuring the turbidity of water in which rice is soaked, and the turbidity measured in this turbidity measurement step, the degree of degradation of rice is determined. Since the deterioration degree determining step for determining is provided, the deterioration degree of the rice can be determined without boiling the water in which the rice is soaked (rice cooked water).

FIG. 1 is a line graph of an experimental example of a method for determining the degree of deterioration of rice according to the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a rice cooker according to a second embodiment of the present invention. FIG. 3 is an enlarged side view of the lower end of the turbidity sensor. FIG. 4 is a schematic cross-sectional view of the lower end portion of the turbidity sensor. FIG. 5 is a control block diagram of the rice cooker. FIG. 6A is a flowchart for explaining the control of the rice cooker. FIG. 6B is a flowchart for explaining the control of the rice cooker. FIG. 7 is a graph showing a change in the temperature of water during cooking of the rice cooker. FIG. 8 is an enlarged side view of a lower end portion of a modified example of the turbidity sensor. FIG. 9 is a schematic cross-sectional view of the lower end portion of the modified example. FIG. 10 is a graph showing another example of the temperature change of water during the rice cooking of the rice cooker. FIG. 11 is a modification of the control block diagram of the rice cooker.

  Hereinafter, the rice cooker of this invention is demonstrated in detail by embodiment of illustration.

[First embodiment]
In the first embodiment, an example of a method for determining the degree of deterioration of rice according to the present invention will be described. An example of a method for determining the degree of degradation of this rice is a stirring step of stirring the measured rice in the state of white rice in water, a turbidity measuring step of measuring the turbidity of the suspension obtained in this stirring step, A deterioration degree determining step for determining the deterioration degree of the rice to be measured based on the turbidity measured in the turbidity measuring step.

  Next, a method for measuring the turbidity will be described. First, a certain amount of rice to be measured and water are put into a predetermined container (not shown) and stirred at a constant load. As a stirring method, there are a method of rotating a stirring blade arranged in the container at a constant rotation number, a method of vibrating the container at a constant frequency by a shaker, and the like. By the stirring in the water, solid components mainly composed of starch flow out from the rice to the water. This solid component is easy to be compatible with water if it is a new rice, and starch begins to flow out immediately, but if it is an old rice, it is highly hydrophobic, so the flow rate of starch is slowed down. The turbidity of the filtrate suspension is measured after a certain time from the start of stirring of the rice to be measured. Since the turbidity of the solution after a certain period of time decreases as the conversion to old rice progresses, the measured turbidity is the same as the reference value, or if it is lower than the reference value, it is determined as old rice, and if it is higher than the reference value, it is determined as new rice be able to. Therefore, the degree of rice degradation can be determined without boiling the water.

  Further, if the time for stirring the rice is changed according to the degree of deterioration of the rice, it is possible to prevent the washing rice from becoming excessive or insufficient.

  Moreover, since the degree of deterioration of rice can be determined without boiling the water, appropriate heating control can be performed before and after boiling the water.

(Experimental data)
FIG. 1 shows data obtained by actually measuring the relationship between the deterioration of rice and the turbidity of the washed rice liquid. Here, the rate of deterioration of the rice greatly depends on the temperature at the time of storage, and the deterioration is very slow at a low temperature of 15 ° C. or lower (there is almost no change in chemical composition), but the old rice with the passage of time at 25 ° C. or higher. It has been found that the values of fatty acids and the like, which are regarded as indicators, increase. Furthermore, brown rice stored at 40 ° C. for 1 month has been shown to have the same degree of deterioration as room temperature storage for 1 year (Reference: An efficient method for evaluating the palatability deterioration during storage in rice (Plant Production Science Vol. 6, 2003)). The above data is obtained using Niigata Koshihikari produced in 2010. More specifically, Niigata Koshihikari brown rice produced in 2010 was stored at 40 ° C. to promote deterioration, and white rice obtained by polishing with a household rice mill after a certain period of time was used as the sample rice. The turbidity of was measured. In addition, 0W-8W of FIG. 1 has shown that the deterioration promotion period is 0 weeks-8 weeks. For example, 2W means that the brown rice obtained from Niigata Koshihikari rice produced in 2010 at 40 ° C. for 2 weeks and then polished with a household rice mill is used as the sample rice.

  450 g of the sample rice and 1 L of tap water are put in a kettle. A stirring blade that can be rotationally driven by a motor is disposed in the pot. The sample rice is stirred by rotationally driving the stirring blade at 400 rpm. And after 0 minutes (immediately after immersion) and 1, 3, 5 and 10 minutes after the stirring blade starts stirring, 1 mL of the rice washing liquid in the kettle is sampled and diluted 30 times with ion-exchanged water. It put into the cell of 2 cm of cell length, and measured turbidity with the commercially available turbidimeter. Such measurement was performed on the sample rice whose deterioration promotion period was 0 weeks, 1 week,... And 8 weeks. As a result, as shown in FIG. 1, it was found that the turbidity of the rice washing liquid after stirring for a certain time decreases as the degree of deterioration increases. Here, NTU is a unit of measurement of turbidity when scattered light is measured using formazine as a standard solution.

  In the first embodiment, the turbidity is measured based on the scattered light. However, the turbidity may be measured based on the transmitted light.

[Second Embodiment]
In FIG. 2, the cross section which cut the rice cooker of 2nd Example of this invention with the vertical surface is shown typically.

  The rice cooker includes a rice cooker main body 1, a lid 2 attached to the rice cooker main body 1 so as to be freely opened and closed, and a bottomed cylindrical inner pot 3 that is stored in the rice cooker main body 1 and contains rice and water. It is equipped with.

  The said rice cooker main body 1 has the outer pot 51 in which the inner pot 3 is accommodated. A heater 4 that directly or indirectly heats the inner pot 3 and a contact-type temperature sensor 5 that detects the temperature of the inner pot 3 are disposed between the outer pot 51 and the inner pot 3. Moreover, the operation panel 40 mentioned later is provided in the side part of the rice cooker main body 1. FIG. The heater 4 is an example of a heating unit.

  The outer pot 51 is formed of a material having heat resistance and electrical insulation. In addition, a through hole is provided in the center of the bottom of the outer pot 51, and a bottomed cylindrical cover 6 is inserted through the through hole.

  The cover 6 covers the shaft portion 7a of the motor 7 and the rotor 8 connected to the shaft portion 7a. A plurality of drive-side magnets 9 are attached to the outer peripheral portion of the rotor 8 at equal intervals in the circumferential direction. In a state where the inner pot 3 is housed in the outer pot 51, the drive side magnet 9 enters the recess 3 a of the inner pot 3. The motor 7 is an example of the rotational drive device of the present invention.

  The inner pot 3 is formed of a high heat conductive member such as aluminum, for example, and the inner surface of the high heat conductive member is coated with a fluororesin in order to prevent adhesion of rice or the like. The high heat conductive member is molded by pressing or casting. On the outer surface of the substantially central portion of the bottom of the inner pot 3, a recess 3a having a substantially circular shape as viewed from below is provided. Moreover, the convex part is formed in the inner surface of the center part of the bottom part of the inner pot 3 with formation of the recessed part 3a. A stirring blade 10 for stirring the rice 15 in the inner pot 3 is rotatably attached to the convex portion. The stirring blade 10 is an example of the stirring body of the present invention.

  The stirring blade 10 holds an annular yoke 50 and a plurality of driven-side magnets 11 attached to the inner peripheral portion of the yoke 50 at equal intervals in the circumferential direction. The driven magnet 11 is magnetically coupled to the driving magnet 9 in a direction perpendicular to the rotation axis of the motor 7. Thus, when the motor 7 rotates the rotor 8, the stirring blade 10 can also be rotated. Further, a drop-off prevention magnet 12 is attached to the upper part of the stirring blade 10 to prevent it from falling off the convex portion.

  A turbidity sensor 13 for measuring the turbidity of the water 14 in the inner pot 3 is disposed in the inner pot 3. The upper end of the turbidity sensor 13 is swingably attached to the lower part of the lid 2 via, for example, a hinge. This prevents the lower end of the turbidity sensor 13 from being caught on the inner surface of the inner pot 3 when the lid 2 is opened. In addition, a plurality of rice 15 (only five are shown in FIG. 2) are immersed in the water 14.

  In FIG. 3, the enlarged view of the lower end part of the said turbidity sensor 13 is shown. FIG. 4 schematically shows a cross section of the lower end portion of the turbidity sensor 13.

  As shown in FIGS. 3 and 4, the turbidity sensor 13 has a structure for measuring turbidity based on the intensity of transmitted light. More specifically, the turbidity sensor 13 includes a cylindrical case 16, a light source 17 disposed in the case 16, and a light receiving element 18 positioned almost directly below the light source 17 in the case 16. Yes. A concave portion 16 a is provided on the side surface of the lower end portion of the case 16. A filter 19 is attached to the side surface of the lower end portion of the case 16 so as to cover the recess 16a. Thereby, the water 14 is put into the recess 16a, but the rice 15 is not put into the recess 16a. Further, at least a portion of the recess 16a facing the light source 17 and the light receiving element 18 is made of a material that can transmit the light emitted from the light source 17.

  FIG. 5 shows a control block diagram of the rice cooker.

  The rice cooker includes a determination unit 20, a control unit 30 having a motor control unit 31 and a heater control unit 32, a rice washing mode selection unit 41, a rice cooking mode selection unit 42, and an operation panel having a liquid crystal display unit (not shown). 40. The determination unit 20 is an example of a deterioration degree determination unit of the present invention. Further, the turbidity sensor 13 and the determination unit 20 constitute an example of a deterioration degree determination mechanism.

  The determination unit 20 receives a signal indicating the turbidity of the water 14 from the turbidity sensor 13. Then, the determination unit 20 determines the degree of deterioration of the rice 15 based on the signal, and sends a signal corresponding to the degree of deterioration of the rice 15 to the motor control unit 31 and the heater control unit 32.

  The motor control unit 31 controls the motor 7 based on a signal from the determination unit 20, a signal from the rice washing mode selection unit 41, and a signal from the rice cooking mode selection unit 42. The rice washing mode selection unit 41 and the rice cooking mode selection unit 42 include, for example, buttons provided on the operation panel 40.

  The heater control unit 32 controls the heater 4 based on the signal from the determination unit 20 and the signal from the rice cooking mode selection unit 42.

  6A and 6B are flowcharts for explaining control of the heater 4 and the motor 7 by the control unit 30. FIG. In the above control, the user puts the desired amount of rice 15 and the amount of water 14 corresponding to the amount of the rice 15 into the inner pot 3, then closes the lid 2, and the rice washing mode selection unit 41. Select to start.

  When the control starts, as shown in FIG. 6A, the motor control unit 31 turns on the motor 7 to rotate the stirring blade 10 and stir the rice 15 in step S101. At this time, the motor control unit 31 controls the motor 7 so that the stirring blade 9 rotates at a constant rotation speed (for example, 400 rpm). The amount of the solid component eluted from the rice 15 can be controlled by rotating the stirring blade 9 at a constant rotational speed.

  Next, in step S102, it is determined whether or not a predetermined time (for example, 60 seconds) has elapsed since the rotation of the stirring blade 10 started. If it is determined in step S102 that a predetermined time has elapsed from the start of rotation of the stirring blade 10, the process proceeds to the next step S103, while a predetermined time has elapsed from the start of rotation of the stirring blade 10. If determined, step S102 is performed again. That is, step S102 is repeated until it is determined that a predetermined time has elapsed from the start of rotation of the stirring blade 10.

  Next, the turbidity of the water 14 during the stirring of the rice 15 is measured by the turbidity sensor 13 in step S103. Here, since the stirring blade 9 is rotating at a constant rotational speed, the dispersion of the solid components in the water 14 can be kept uniform, so that the turbidity of the water 14 can be accurately measured.

  Next, in step S104, it is determined whether or not the turbidity of the water 14 measured by the turbidity sensor 13 exceeds 250 NTU. If it is determined in step S104 that the turbidity of the water 14 measured by the turbidity sensor 13 exceeds 250 NTU, the process proceeds to step S105, while the turbidity of the water 14 measured by the turbidity sensor 13 is If it is determined that it does not exceed 250 NTU, the process proceeds to step S201 shown in FIG. 6B. That is, in step S104, if the rice 15 is a new rice, the process proceeds to step S105. If the rice 15 is an old rice, the process proceeds to step S201. The determination of new rice and old rice is performed by the determination unit 20 and is transmitted to the motor control unit 31 and the heater control unit 32.

  When the process proceeds to step S <b> 105 shown in FIG. 6A, the motor 7 is turned off by the motor control unit 31.

  Next, in step S106, the end of washing is notified. Specifically, a message indicating that the rice washing has been completed is displayed on the liquid crystal display unit of the operation panel 40.

  Next, in step S107, it is determined whether or not the lid 2 has been opened and closed again. This step S107 is repeated until it is determined that the lid 2 is opened and closed again. Step S <b> 107 is a step for determining whether or not the user has thrown away the water 14 in the inner pot 3 and newly put water into the inner pot 3.

  Next, in step S108, it is determined whether or not the rice cooking mode selection unit 42 has been selected. This step S108 is repeated until the rice cooking mode selection unit 42 is selected.

  Next, when the rice cooking sequence for new rice is performed in step S109, the control of the flowcharts of FIGS. 6A and 6B ends.

  When it progresses to step S201 shown to FIG. 6B, it is determined whether predetermined time (for example, 300 seconds) passed since the rotation start of the stirring blade 10. FIG. This step S201 is repeated until it is determined that a predetermined time has elapsed from the start of rotation of the stirring blade 10.

  Next, the motor 7 is turned off by the motor control unit 31 in step S202.

  Next, in step S203, as in step S106, a rice washing end notification is performed.

  Next, in step S204, it is determined whether or not the lid 2 has been opened and closed again. This step S204 is repeated until it is determined that the lid 2 is opened and closed again. The purpose of step S204 is the same as that of step S107.

  Next, in step S205, it is determined whether or not the rice cooking mode selection unit 42 has been selected. This step S108 is repeated until the rice cooking mode selection unit 42 is selected.

  Next, when the rice cooking sequence for used rice is performed in step S206, the control of the flowcharts of FIGS. 6A and 6B ends.

  Thus, the degree of deterioration of the rice 15 can be determined without boiling the water 14.

  Further, since the motor control unit 31 determines that the rice 15 is a new rice, the motor 7 is turned off and the washing is stopped, so that the rice 15 can be prevented from being washed excessively.

  Moreover, since the said motor control part 31 extends the rice washing time according to the judgment that the rice 15 is an old rice, the tastes, such as hardness and stickiness of the rice 15 after rice cooking, improve, and an old rice smell is also reduced. be able to.

  Therefore, proper rice washing according to the state of the rice 15 can be performed by the control of the motor 7 by the motor control unit 31.

  Moreover, since the rice cooking sequence for new rice or the rice cooking sequence for old rice is performed according to the judgment that the said rice 15 is new rice or old rice, the proper rice cooking sequence according to the state of the rice 15 can be performed.

  In FIG. 7, the graph for demonstrating the rice cooking sequence of the said rice cooker is shown.

  The above rice cooking sequence is an example of a rice cooking sequence for old rice, and the temperature of the water 14 is kept at 60 ° C for a preset time, and the temperature of the water 14 is kept at 100 ° C for a preset time. Has a boiling period. Softening the rice 15 by driving the motor 7 during the 60 ° C. keeping period to increase the amount of solid components eluted from the rice 15 or by controlling the heater 4 to extend the boiling period. Can do.

  On the other hand, in the rice cooking sequence for new rice, in order to prevent the rice 15 from becoming too sticky and becoming lumpy, the motor 7 is stopped during the 60 ° C keep period or the boiling time is used for old rice. Or make it shorter than the boiling time of the rice cooking sequence.

  In the second embodiment, the stirring blade 10 and the shaft portion 7a of the motor 7 are magnetically coupled. However, the stirring blade 10 and the shaft portion 7a of the motor 7 may be physically coupled. For example, a direct drive method may be adopted as a method for transmitting the rotational force of the motor 7.

  In the second embodiment, the rice 15 may be washed using a vibration device capable of applying vibration to the water 14 and the rice 15 instead of the stirring blade 10. In addition, you may arrange | position the said vibration apparatus in the inner pot 3 or the inner pot 3 outside.

  In the second embodiment, steps S108 and S205 are performed after steps S107 and S204, but steps S108 and S205 are omitted, and steps S109 and S206 are performed after steps S107 and S204. Also good. That is, if it is determined in steps S107 and S204 that the lid 2 is opened and closed again, steps SS109 and S206 may be executed immediately.

  In the said 2nd Example, although the turbidity sensor 13 which measures the turbidity of the water 14 in the inner pot 3 was arrange | positioned in the inner pot 3, the turbidity of the water in an inner pot was located in the inner pot peripheral part. A turbidity sensor for measuring the degree may be arranged. That is, you may arrange | position a turbidity sensor so that the outer peripheral wall of the inner pot 3 may be opposed. When this turbidity sensor is used, a portion facing the turbidity sensor in the inner pot may be formed of a transparent material.

  In the second embodiment, instead of the turbidity sensor 13 of FIGS. 3 and 4 that measures the turbidity of the water 14 based on the intensity of the transmitted light, the turbidity of the water is measured based on the intensity of the scattered light. The turbidity sensor 113 shown in FIG. 9 may be used.

  As shown in FIGS. 8 and 9, the turbidity sensor 113 has a structure for measuring the turbidity based on the intensity of transmitted light. More specifically, the turbidity sensor 113 includes a cylindrical case 116, a light source 17 disposed in the case 116, and a light receiving element 18 positioned obliquely below the light source 17 in the case 116. Yes. A concave portion 16 a is provided from the side surface to the bottom surface of the lower end portion of the case 116. A filter 119 is attached to the lower end of the case 116 so as to cover the recess 16a. Thereby, the water 14 is put into the recess 16aa, but the rice 15 is not put into the recess 16a. Further, at least a portion of the recess 16a facing the light source 17 and the light receiving element 18 is made of a material that can transmit the light emitted from the light source 17.

  In the second embodiment, the determination of the degree of deterioration of the rice 15 by the determination unit 20 may be performed within 1 minute after the start of rice washing by stirring of the stirring blade 10. In such a determination, the determination accuracy of the degree of deterioration of the rice 15 can be increased.

  In the said 2nd Example, you may make it make the rice cooking time of the rice cooking sequence for used rice differ from the rice cooking time of the rice cooking sequence for new rice.

  The rice cooker of the said 2nd Example may perform the rice cooking sequence which concerns on the graph of FIG. This rice cooking sequence is an example of a rice cooking sequence for old rice, and has a low temperature keeping period, a 60 ° C. keeping period, and a boiling period.

  The time of the low temperature keep period is the time from the start of cooking rice 15 until immediately before the heater 4 is turned on. In other words, the time of the low temperature keeping period keeps the temperature of the water 14 in the inner pot 3 at the same level as the temperature at the start of cooking rice 15 with the heater 4 turned off. Any time. By this low temperature keeping period, the rice 15 is sufficiently absorbed before the start of gelatinization, thereby achieving ideal rice cooking.

  The time of the 60 ° C. keeping period is an arbitrary time for keeping the temperature of the water 14 in the inner pot 3 at 60 ° C. by heating the heater 4. By this 60 ° C. keeping period, a large amount of glucose, which is a sweet component, is produced in the rice 15. Note that the temperature of the water 14 in the inner pot 3 is indirectly detected based on the output signal of the temperature sensor 5.

  The time of the boiling period is an arbitrary time for keeping the temperature of the water 14 in the inner pot 3 at about 100 ° C. by heating the heater 4.

  Also, since old rice is less likely to absorb water than new rice, the heater 4 is controlled to extend the time of the low temperature keep period. In addition, since old rice tends to have a hard and crisp texture, the motor 7 is driven during the low temperature keeping period to increase the amount of solid components eluted from the rice 15 and the heater 4 is controlled to increase the time of the 60 ° C. keeping period. By making it longer, the rice obtained from the rice 15 is brought closer to the sticky rice. By doing so, the taste of old rice can be improved.

  In FIG. 11, the control block diagram of the rice cooker which concerns on the graph of FIG. 10 is shown. In FIG. 11, the same components as those shown in FIG. 5 are given the same reference numerals as those in FIG.

  The rice cooker includes a control unit 130. The control unit 130 includes a motor control unit 31, a heater control unit 32, an excess determination unit 131 as an example of an excess determination unit, a low keep period stirring unit 132 as an example of a low keep period stirring unit, and a water temperature maintenance. It has a water temperature maintaining unit 133 as an example of the means. In FIG. 11, as in FIG. 5, a diagram showing that the output signal from the temperature sensor 5 is input to the control unit 130 is omitted.

  The excess determination unit 131 determines whether or not the degree of deterioration of the rice 15 determined by the determination unit 20 is greater than a preset value. The above values are values stored in advance in a storage unit (not shown).

  When the excess determination unit 131 determines that the degree of deterioration of the rice 15 is greater than a preset value, the low temperature keep period stirring unit 132 drives the motor 7 during the low temperature keep period to Stir with the stirring blade 10. The time for stirring the rice 15 with the stirring blade 10 is a preset time that is equal to or less than the time of the low temperature keep period. The time for stirring the rice 15 with the stirring blade 10 may be determined according to the degree of deterioration of the rice 15 within a range not exceeding the time of the low temperature keeping period.

  The water temperature maintenance unit 133 changes the time of the 60 ° C. keep period based on the degree of deterioration of the rice 15 determined by the determination unit 20. More specifically, if the degree of deterioration of the rice 15 is relatively small, the time of the 60 ° C. keep period is relatively short, while if the degree of deterioration of the rice 15 is relatively large, the time of the 60 ° C. keep period is relatively long. It has become a long time. That is, the time is increased as the degree of deterioration of the rice 15 increases.

  On the other hand, in the rice cooking sequence for new rice, in order to prevent the rice 15 from becoming too sticky and becoming lumpy, the motor 7 is stopped during the low temperature keep period, or the 60 ° C keep period is used for the old rice. Or shorter than in the cooking rice sequence.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the first and second embodiments described above, and various modifications can be made within the scope of the present invention. For example, the present invention can be applied not only to a heater heating type rice cooker but also to an induction heating type rice cooker. Moreover, what combined suitably the description matter of the said 1st, 2nd Example is good also as one Example of this invention.

  The method for determining the degree of deterioration of rice according to the present invention does not include a stirring step of stirring the rice soaked in water, but a turbidity measuring step of measuring the turbidity of water soaked in rice, and this turbidity measuring step. And a deterioration degree determination step for determining the degree of rice deterioration based on the turbidity measured in step (b).

  In addition, the rice cooker of the present invention does not have a mechanism for stirring rice, but measures the turbidity of water in which rice is soaked, and determines the degree of deterioration based on this turbidity. A mechanism may be provided.

  Moreover, the rice cooker of this invention may select automatically at least one of rice washing time and a rice cooking sequence (for example, rice cooking time) according to the deterioration degree of rice.

DESCRIPTION OF SYMBOLS 1 ... Rice cooker main body 2 ... Cover 3 ... Inner pan 4 ... Heater 5 ... Temperature sensor 6 ... Cover 7 ... Motor 8 ... Rotor 9 ... Drive side magnet 10 ... Stirring blade 11 ... Driven side magnet 13 ... Turbidity sensor 14 ... Water 15 ... Rice 16 ... Light source 17 ... Light receiving unit 19,119 ... Filter 130 ... Excess determining unit 132 ... Low keep period stirring unit 133 ... Water temperature maintaining unit

Claims (10)

  A rice cooker comprising a deterioration degree determination mechanism for measuring the turbidity of water soaked with rice and determining the degree of deterioration of the rice based on the turbidity. In the rice cooker according to claim 1,
An inner pot that houses rice with water,
A heating unit arranged outside the inner pot and for heating the inner pot;
It is arranged in the inner pot, and comprises a stirring body for stirring the rice in the inner pot,
The deterioration degree determination mechanism is
A turbidity sensor that is arranged in the inner pot or in the inner pot periphery, and measures the turbidity of water in the inner pot,
A rice cooker comprising: a deterioration degree determination unit that determines the degree of deterioration of rice in the inner pot based on the turbidity measured by the turbidity sensor. In the rice cooker according to claim 2,
The determination of the degree of deterioration of rice by the deterioration degree determination unit is performed within 1 minute after the washing of rice by stirring of the stirring body is started. In the rice cooker according to claim 2 or 3,
A rice cooker that automatically selects a rice washing time and a rice cooking sequence according to the degree of deterioration of the rice determined by the deterioration determining unit. In the rice cooker as described in any one of Claim 2 to 4,
Excess determination means for determining whether or not the degree of deterioration of rice determined by the deterioration determination unit is greater than a preset value;
When it is determined by the excess determination means that the degree of deterioration of the rice is greater than a preset value, the low temperature from the start of rice cooking to just before the heating of the heating unit starts A rice cooker comprising: a low temperature keeping period stirring means for stirring the rice with the stirring body during the keeping period. In the rice cooker according to claim 5,
Water temperature maintaining means for maintaining the temperature of the water in which the rice is soaked at 60 ° C. by heating of the heating unit, according to the degree of deterioration of the rice,
The rice cooker characterized in that the time becomes longer as the degree of deterioration of the rice increases. In the rice cooker as described in any one of Claim 2 to 6,
A rice cooker comprising a rotation drive device that rotationally drives the agitator. In the rice cooker as described in any one of Claim 2-7,
The said turbidity sensor has a light source and a light-receiving part which receives the light resulting from this light source, The rice cooker characterized by the above-mentioned. A turbidity measurement process for measuring the turbidity of water soaked with rice,
A degradation level determination method for rice, comprising: a degradation level determination step for determining a degradation level of the rice based on the turbidity measured in the turbidity measurement step. In the method for determining the degree of deterioration of rice according to claim 9,
It has a stirring process that stirs rice that has been soaked in water,
The method for determining a degree of deterioration of rice, wherein the turbidity measuring step is performed after the rice is stirred in the stirring step.

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