JP2005168546A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker capable of cooking delicious rice by making water content sufficient at the time of the completion of a water immersion process. <P>SOLUTION: In the rice cooker having a cooking out process and then a steaming process after the water immersion process, the water content of the rice is made high before starting the water immersion process by a water preimmersion process with steam before the water immersion process. Thus the water content of the rice before the completion of the water immersion process becomes sufficient, so that the delicious rice can be cooked. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rice cooker using steam.

  In the conventional general rice cooker, as shown in FIG. 7, the rice cooking method which cooks rice in three processes, a water immersion process (A), a cooking process (B), and a steaming process (C) based on the temperature of a pan bottom. Is used. In the water immersion process (A), water is absorbed up to the inside of the rice.

  When rice with sufficient moisture is heated for a certain period of time, the rice is gelatinized and becomes rice. The process of applying heat for a certain period of time changes from the cooking process (B) in FIG. 7 to the steaming process (C). Therefore, it is necessary for rice to absorb about 30% or more of water. Therefore, it is important to absorb water sufficiently from the surface of the rice grain to the inside so that the rice grain can be gelatinized and cooked smoothly.

  Here, the change of the moisture content of the rice in a water immersion process is shown in FIG. The moisture content of rice is affected by the temperature of the water to be submerged and the time of inundation. In general, the higher the water temperature for immersing rice, the faster water is absorbed.

  However, when the water is immersed above 60 ° C., which is the gelatinization temperature of rice, the surface of the rice is gelatinized to prevent water absorption inside. Therefore, in the current rice cooker, in order to shorten the cooking time as much as possible, for the purpose of speeding up the water absorption, the rice is kept at a maximum temperature (for example, 55 ° C. to 58 ° C.) within a range where the rice does not become a lake. Inundation process is set.

  As shown in FIG. 8, water immersion at 55 ° C. water temperature is faster than water at 20 ° C., but water absorption into rice is faster, but even when immersed for 30 minutes or more, the water content becomes constant around 30%. No more water is absorbed. Therefore, the water immersion process is carried out at 55 ° C. to 58 ° C. for about 20 minutes, and after this, the rice is absorbed through the steaming process, and the water content reaches 63% at the end of the rice cooking.

As a rice cooker that promotes water absorption into the rice during the water immersion process, for example, there is a rice cooker equipped with steam generating means. By supplying steam from the upper part of the pot during the inundation process and increasing the amount of heat, the temperature of the water at the beginning of cooking is increased to a temperature where gelatinization does not occur in a short time, and the rise time of the water temperature is shortened, The water absorption speed of rice is increased (for example, see Patent Document 1).
JP 2003-144308 A

  However, as in the conventional rice cooker above, even if the temperature of water at the initial stage of rice cooking is raised to a temperature at which gelatinization does not occur in a short time, and even if the water absorption rate of rice is increased, water absorption into the rice during the water immersion process is not It was not enough.

  This invention solves such a conventional subject, and it aims at providing the rice cooker which can cook delicious rice by the water absorption to the rice at the time of a water immersion process being fully performed.

  In order to achieve the above object, the present invention provides a rice cooker having a cooking process and then a steaming process after the water immersion process and a preliminary water immersion process using steam before the water immersion process.

  By providing a pre-soak process with steam, when steam is supplied, the steam is rapidly cooled and condensed on the rice surface, and water droplets adhere to the rice surface. This is because the temperature of rice before flooding is about the same as room temperature, which is lower than steam. Furthermore, since the rice before being soaked is heated by steam and easily absorbs water, it absorbs water droplets on the surface of the rice and increases the moisture content of the rice.

  As a result, since the moisture content of the rice is increased before the start of the flooding process, the moisture content of the rice becomes sufficient at the end of the flooding process, and delicious rice can be cooked.

  After the soaking process, the rice cooker having the cooking process and then the steaming process is provided with a preliminary soaking process using steam before the soaking process, and the water content of the rice is increased before the soaking process is completed. Sometimes the water content of the rice is sufficient and you can cook delicious rice.

  In the embodiment of the present invention, after the soaking process, the rice cooker having the cooking process and then the steaming process is provided with a preliminary soaking process using steam before the soaking process, and the water content of the rice before the soaking process is increased. By increasing the water content of the rice at the end of the flooding process, it is possible to cook delicious rice.

  Further, when steam is supplied intermittently, the surface of the rice does not become too hot, and gelatinization before the water immersion process is prevented, so that water absorption can be prevented from being hindered by gelatinization.

  In addition, if the amount of water supplied automatically after the pre-flooding process is controlled according to the amount of rice, an appropriate amount of water can be supplied according to the amount of rice. Hardness unevenness can be eliminated.

  In addition, if the pan is equipped with a rice storage container made of a vapor permeable material, and steam is supplied with the rice stored in the rice storage container, the steam fills the bottom of the rice cooker pan, Since steam can be supplied to the entire rice, steam can be supplied to the entire rice without any unevenness.

  If steam is supplied from above and below in the pot, steam can be supplied from above and below in the pot of the rice cooker, steam can be supplied to the whole rice, and it reaches the bottom from above the pot. Since there is no need to send steam at such a high flow rate, a minimum amount of steam is required.

  Embodiments will be described below with reference to the accompanying drawings.

(Example 1)
A first embodiment of the present invention will be described with reference to FIG. 1 shown in FIG. 1 shows a rice cooker main body, and is equipped with a detachable pan 2. Further, a lid 3 that covers the upper surface of the pan 2 is provided so as to be freely opened and closed. Moreover, a pan heating means 4 for heating the pan 2, for example, a pan temperature detecting means 5 for detecting the temperature of the heating coil and the bottom of the pan 2, for example, a thermistor, is disposed inside the rice cooker body 1. The rice cooker body 1 includes a tank 6, and the steam generation means 8 is constituted by the tank 6 and the water heating means 7 that heats the water in the tank 6. The tank 6 may be configured to be detachable.

  Further, a steam heating means 10 for heating the steam in the steam supply path 9 is arranged outside a part of the steam supply path 9 in order to heat the generated steam. The steam heating means 10 may be provided inside a part of the steam supply path 9. Moreover, the control means 11 is provided in the inside of the rice cooker main body 1, The control means 11 controls the pot heating means 4 and the water heating means 7 based on the output of the pot temperature detection means 5, and further heated. The steam heating means 10 is controlled based on the steam temperature.

  Note that the steam generated by the steam generating means 8 may not be heated. This is because even the unheated steam can achieve the purpose of heating the rice before the water immersion process and allowing the rice to absorb water.

  Further, a steam hole 12 is provided in the opening of the lid 3 in order to release excess steam in the pan 2. In addition, a rice storage container 13 made of a detachable vapor-permeable material, for example, a non-container, is placed in the pan 2 at a foot height so that a slight space is formed with the bottom of the pan 2.

  The rice storage container 13 is not limited to a non-container container, and may be any hole that is smaller than rice grains and allows passage of steam, or has a space, and has a plate-like hole through which several rice grains do not pass. It may be what you did. Further, the material may be made of ceramic, plastic having heat resistance of 100 ° C. or higher, and metal, and the metal may be processed with fluorine coating for preventing rust.

  The operation of the above configuration will be described with reference to the flowchart of FIG. The rice before the water immersion process is put in the rice storage container 13 and the rice storage container 13 is installed in a predetermined position in the pan 2 (step 1). Next, when predetermined water is put into a tank 6 provided in the rice cooker body 1 and a user selects a rice cooker switch (not shown), first, steam at 100 ° C. is generated by the steam generating means 8, Further, steam heated to a predetermined temperature, for example, 110 ° C. by the steam heating means 10 is supplied into the pan 2 through the steam supply path 9 (step 2).

  In addition, the supply of steam at the time of this preliminary water immersion step may be intermittently supplied to the rice before the water immersion. By doing so, even if the surface of the rice instantaneously exceeds 100 ° C, the surface of the rice does not become too hot before the water immersion process, and gelatinization is performed to prevent gelatinization before the water immersion process. Can prevent the water absorption from being hindered. The tank 6 may be detachable.

  The steam heating means 10 is controlled by the control means 11, and when heated steam exceeding a predetermined temperature, for example, 130 ° C. is supplied to the rice, the rice surface becomes too hot and gelatinized, The gelatinization prevents water absorption. For this reason, the heating of the steam is controlled to be equal to or lower than this temperature.

  Moreover, the vapor | steam at the time of this preliminary | backup water immersion process is supplied with the flow velocity of the grade which has the momentum which reaches the bottom part from the upper direction of the pan 2. As shown in FIG. Since the bottom of the pan 2 has a space by the rice storage container 13, the heated steam flows upward from the lower part of the rice in the rice storage container 13 through the gap between the rice grains, and touches the rice surface evenly. And the control means 11 detects having reached | attained predetermined time, for example, 5 minutes, after supplying steam in the pan 2 (step 3), and stops injection | throwing-in of the heated steam (step 4).

  Next, the user throws into the pan 2 an amount of water suitable for the amount of rice put in the rice storage container 13 (step 5). After detecting the opening and closing of the lid 3 at this time, the pot heating means 4 is activated and rice cooking is started (step 6). Note that the water in the tank 6 may be automatically supplied through the steam supply path 9 instead of being supplied by the user. This is because the rice can be automatically immersed in water after the preliminary soaking process, so that the transition to the soaking process can be performed quickly.

  As shown in FIG. 7, the rice cooking process proceeds with a water immersion process (A), a cooking process (B), and a steaming process (C). A normal rice cooking process starts by immersing the rice, raises the water temperature to a temperature at which the rice below 60 ° C. does not gelatinize, and holds the temperature for a certain period of time. FIG. 7 shows changes in the moisture content of rice during the water immersion process. In the soaking process of the normal rice cooking method, the water content increases with the water soaking time, and it takes about 15 minutes or more to reach the maximum water content of about 30%. Therefore, in the water immersion process of a normal rice cooking method, the temperature of less than 60 ° C. is maintained for 15 to 20 minutes at a temperature at which gelatin does not gelatinize.

  However, when the preliminary water immersion process is provided before the water immersion process, as shown in FIG. 3, a maximum water content of 50% higher than that of a normal rice cooking method can be obtained in a short time.

  In a normal rice cooking method, water absorption and gelatinization proceed simultaneously during the cooking process after the water immersion process, and the water content increases to about 63%, which is slightly more than twice that of the immersion process by the end of the rice cooking process. If sufficient moisture content is obtained by the start of the cooking process, gelatinization will be promoted by heating, resulting in delicious rice, but if the moisture content at the start of the cooking process is less than about 30%, It becomes inadequate and it becomes rice with the core remaining.

  In the rice cooker with a pre-flooding process with steam before the water immersion process, the rice water content before the start of the water immersion process is increased by the rice cooker having the cooking process and then the steaming process after the water immersion process. Immediately after the start of the inundation process, a moisture content close to the end of normal rice cooking was obtained, and sufficient water absorption was ensured at the start of the cooking process. You can cook.

  In addition, you may supply the vapor | steam heated also at the time of a cooking process or a steaming process. By increasing the amount of heat at the time of cooking, gelatinization can be promoted and the cooking time can be shortened. In addition, a menu button for supplying steam before eating may be provided in order to prevent the rice being kept warm from drying.

(Example 2)
A second embodiment of the present invention will be described with reference to FIG. In FIG. 4, at least two weight sensors 14 are installed so as to come into contact with the insulating portion 15 of the pan 2 when the detachable pan 2 is installed in the rice cooker body 1. The tank 6 into which water is divided is divided into two parts. A pump 16 is provided on one side of the tank 6 to serve as a water supply mechanism, and a water heating means 7 is provided on the other side of the tank 6 to provide steam generation means 8. It is said. The water sent by the pump 16 is configured to be supplied to the pot 2 from the steam supply path 9 connected via the on-off valve 17. The tank 6 may be configured to be detachable. Further, the control means 11 controls the steam generation means 8, the steam heating means 10, the pump 16, and the on-off valve 17 based on the detection of the weight sensor 14.

  The operation of the above configuration will be described with reference to the flowchart of FIG. After putting the rice in the rice storage container 13, the rice is placed in a predetermined position in the pan 2 (step 1). When the pot 2 is installed in the rice cooker body 1, the weight sensor 14 comes into contact with the insulating portion 15 of the pot 2, and the weight sensor 14 detects the total weight of the pot 2, the rice container 13, and the stored rice. The control means 11 calculates by subtracting the weights of the pan 2 and the rice storage container 13 which are invariable values from the total weight detected by the weight sensor 14, and detects the weight of only the rice (step 2).

  Moreover, a user puts predetermined water in the tank 6 provided in the rice cooker main body 1, and a user selects the rice cooking switch (not shown). Note that either the order of adding rice or the order of adding water may be first. After the rice cooking switch is selected, steam is generated from the steam generating means 8, and the steam is heated to a predetermined temperature by the steam heating means 10 and supplied into the pan 2 (step 3). Since the temperature of the rice in the pan 2 until the heated steam is supplied is about the same as the room temperature and is lower than the heated steam, the heated steam is rapidly cooled on the surface of the rice at the start of the preliminary submersion process. To condense. As a result, water droplets adhere to the rice surface and the weight of the rice increases. This weight increase phenomenon continues until the rice surface reaches 100 ° C.

  Thereafter, the control means 11 detects these changes occurring in the weight of the rice during the preliminary soaking process by the weight sensor, and stops the steam generation when the weight increase stops, that is, when the set weight change amount is reached (step 4). (Step 5).

  Then, after the steam generation is stopped, the on-off valve 17 is closed to seal the steam generation path (step 6), and the water in the tank 6 is pumped up by the pump 16 and sent into the pan 2 (step 7). At this time, the control means 11 calculates the amount of water suitable for the rice weight based on the rice weight detected before the start of the pre-soaking process, and sets the total amount of the water amount and the rice weight. Then, water is fed into the pan 2 until the total weight of the rice weight and the water amount reaches the set weight (step 8). When the set weight is reached, the operation of the pump 6 is stopped and rice cooking is started (step 9).

  In this way, when the water is supplied to the pump before the preliminary water immersion process so that the water can be automatically supplied after the preliminary water immersion process, instead of supplying the water after the preliminary water immersion process, the completion after the preliminary water immersion process is completed. There is no need to wait and supply water. Therefore, the operability of cooking rice is improved. Moreover, since this structure enables automatic water supply of the optimal amount of water according to the weight of the rice by the weight sensor, it is possible to eliminate unevenness in the hardness of the cooked rice due to water addition / reduction compared to manual charging.

  Note that the means for controlling the amount of water to be automatically supplied after completion of the preliminary water immersion process according to the amount of rice is not limited to the weight sensor.

  In addition, when water is supplied, since water is sent through the steam supply path 9 after the heated steam has passed, the water temperature rises to warm water due to the residual heat, so that the rice is immersed in the warm water. And water absorption is promoted. As a result, a higher water content can be obtained by immersing the rice in warm water than water after the preliminary water immersion process.

  Further, it is not necessary to attach the water heating means 7 for heating the water of the pump 6, and the equipment configuration is not complicated.

  In addition, when the water heating means 7 which heats the water of the pump 6 is provided, it is possible to adjust the temperature of the water of the pump 6 and supply water at the time of water immersion in a normal rice cooking menu. In addition, the weight sensor 14 detects that there is no rice in the pan 2, and water or hot water is supplied into the pan 2 with the pump 6, or steam is supplied, so that the rice stuck to the pan 2 can be easily removed. The ladle 2 can be easily cleaned.

(Example 3)
A third embodiment of the present invention will be described with reference to FIG. In FIG. 6, the steam branch pipe 18 branched from the steam supply path 9 is configured to supply heated steam to the bottom of the pan 2. With such a configuration, the heated steam that can be supplied into the pan 2 is from two directions from above and from the bottom, and particularly when the amount of cooked rice of 5 go or more is large, the heated steam supplied to the rice Can be eliminated. In addition, in the steam supply heated only from above, a flow rate or a flow rate is necessary so that the steam heated up to the bottom of the pan 2 is distributed. Even with the amount of steam, the steam heated up to the bottom of the pan 2 can be supplied, and the apparatus and the tank 6 can be downsized. The tank 6 and the steam branch pipe 18 may be detachable.

  As described above, after the soaking process, the rice cooker having the cooking process and then the steaming process is provided with a preliminary soaking process using steam before the soaking process, and the moisture content of the rice is increased before the soaking process is started. Thus, the moisture content of the rice becomes sufficient at the end of the water immersion process, and delicious rice can be cooked, so that it can be used for, for example, a commercial rice cooker.

Sectional drawing of the rice cooker which shows Example 1 of this invention Flow chart of the rice cooking process showing Example 1 The graph which shows the change of the moisture content of the rice in the water immersion process of this invention Sectional drawing of the rice cooker which shows the same Example 2 Flow chart of the rice cooking process showing Example 2 Sectional drawing of the rice cooker which shows the same Example 3 The graph which shows the rice cooking process of the conventional rice cooker Graph showing change in moisture content of rice in conventional water immersion process

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rice cooker body 2 Pan 3 Lid 4 Pan heating means 5 Pan temperature detection means 6 Tank 7 Water heating means 8 Steam heating means 9 Steam supply path 10 Steam heating means 11 Control means 12 Steam hole 13 Rice storage container 14 Weight sensor 15 Insulation Part 16 Pump 17 On-off valve 18 Steam branch pipe

Claims (5)

A rice cooker having a cooking process and then a steaming process after the water immersion process, and a preliminary water immersion process using steam before the water immersion process. The rice cooker according to claim 1, wherein steam is supplied intermittently. The rice cooker according to claim 1, wherein the amount of water to be automatically supplied after the preliminary water immersion process is controlled according to the amount of rice. 2. The rice cooker according to claim 1, wherein the pan is provided with a rice storage container made of a vapor-permeable material, and steam is supplied in a state where the rice is stored in the rice storage container. The rice cooker according to claim 1, wherein steam is supplied from above and below the pan.

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