JP2004305267A

JP2004305267A - Rice cooker

Info

Publication number: JP2004305267A
Application number: JP2003099100A
Authority: JP
Inventors: Saori Kako; さおり加古; Yumiko Hirata; 由美子平田; Yoshikazu Horiuchi; 美和堀内; Emi Takakuwa; 恵美高桑; Nobuko Ichiki; 暢子市来
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-04-02
Filing date: 2003-04-02
Publication date: 2004-11-04
Anticipated expiration: 2023-04-02
Also published as: JP4023357B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker capable of automatically boiling up rice always deliciously by determining the preparation state of a user before the start of boiling based on the time of immersion of rice in water and the temperature of a pot and selecting/conducting an optimum water absorbing process according to the determination. <P>SOLUTION: A heating control means of the rice cooker inputs the output from a preliminary immersing time measuring means, whose measurement is started by an outer lid opening time clocking means, and automatically controls a heating means so that the water absorption rate of rice reaches the saturation state when the water absorbing process terminates, being not more than 30%, and the water temperature is 40-60°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は主に家庭用に使用する炊飯器に関するものである。
【０００２】
【従来の技術】
一般に、おいしい飯を得るためには米に充分な水を含ませた後炊飯すればよいことが知られている。炊飯の際の吸水工程は、米の糊化温度（６０〜７０℃）以下の温度で米に水を吸わせる工程であり、予熱工程とも言うことができる。米は、精白米の状態では含水率が１５％前後であるが、飽和状態まで吸水すると含水率約３０％となる。一般的に、浸水温度が高いほど飽和状態に到達する時間は短く、水温５℃で２時間以上、水温２０℃で約１時間、水温６０℃で約２０分である。飽和状態に吸水した米を炊飯すると、米粒の中心まで水分と熱が行き渡り、芯のない良好な食味のごはんが炊きあがる。
【０００３】
現在のマイコンにより制御を行なう炊飯器では、この原理を応用して４０〜５０℃の高温で２０分間の吸水工程を入れ、短時間で吸水させたのち炊き上げるようになっており、鍋内を米の糊化温度より低い温度で一定時間吸水させた後に炊飯加熱を行なうのである（例えば、特許文献１参照）。
【０００４】
また、炊飯量に応じて浸水時間を調整しているものもある（例えば、特許文献２参照）。
【０００５】
また、複数の浸水時間を記憶しておき、状況に応じて使用者が選択できるようにしているものもある（例えば、特許文献３参照）。
【０００６】
【特許文献１】
特公昭５９−２４８１５号公報
【特許文献２】
特公昭６３−４６６８４号公報
【特許文献３】
特開平３−３０７３１号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、使用者の使い方としては、炊飯開始までにあらかじめ浸水させている場合が少なからずある。飽和状態まで浸水させた米をさらに高温浸水させた場合、米の表面の組織が崩れ、べちゃついたごはんになり、食味が劣ってしまう。つまり、使用者が食味を良くしようとした操作が逆に食味を落とす結果になる場合があるのである。このような時には使用者が炊飯器を操作して吸水工程のない、あるいは短縮されたコースを選べば解決されるのだが、その判断は使用者に任され、機器側から自動で最適に炊き上げることはできなかった。
【０００８】
また、飽和までの浸水時間は水温によって異なるが、使用者が日常の炊飯において水温とその最適浸水時間を判断することは困難であり、誰もが常に最適条件で最もおいしく炊き上げるということは難しかった。
【０００９】
本発明は上記のような問題を解決するためになされたもので、使用者の炊飯前の準備状態を浸水時間と鍋温度から判断し、それに応じた最適な吸水工程を実行することで、使用者に負担をかけることなく、自動で常に良好な食味のごはんが得られる炊飯器を提供することを目的とするものである。
【００１０】
【課題を解決するための手段】
上記課題を解決するために本発明は、本体と、本体の内部に収納され米と水を入れる鍋と、鍋を加熱する加熱手段と、本体の外蓋開閉検知手段による外蓋の開閉検知または、外蓋開放時間計測手段による外蓋の一定時間以上の開放時間を計測してから炊飯開始操作が行なわれるまでの時間を予備浸漬時間として測定する予備浸漬時間測定手段と、鍋温度検知手段および予備浸漬時間測定手段からの出力を入力として加熱手段を制御する加熱制御手段を備え、米と水を入れた鍋が本体内部に収納されてから使用者が炊飯を開始する時点までの時間を計測し、さらには鍋温度検出手段による鍋温度から米の吸水状態を算出、加熱制御手段はその状態から所定の最適な吸水状態になるように吸水工程を加減するものである。
【００１１】
なお、この所定の最適な吸水状態については、鋭意研究の結果独自に見出した事象に基づいている。即ち、米の吸水状態とごはんの炊きあがりの食味に関する相関についてである。米の吸水において、飽和吸水率に達するまでの時間は水温が高いほど短いが、飽和吸水状態が長く続くと米の表面が崩れたり米が糊化し始めたりするため、炊飯した場合に食味が劣ってしまう。
【００１２】
また、ごはんのおいしさの要因である甘味となる還元糖は、浸漬水温が高く、時間が長いほど多く生成されるが、この状態が長く続くと同様に、米の表面が崩れたり米が糊化し始めたりするため、炊飯した場合の食味が劣るのである。これらの事象より、米の浸漬温度と時間の関係は、炊き上がりのごはんの触感と甘味、つまりおいしさと相関しているといえる。すなわち、良食味のごはんに炊きあげるための米の吸水状態の至適範囲が存在し、それは米の浸漬温度と時間の条件に置きかえることができるのである。
【００１３】
本発明では使用者が炊飯の準備、つまり米と水の入った鍋を炊飯器にセットした時点から炊飯開始する時点までの時間と温度を計測し、加熱制御手段はその結果から米の吸水状態を算出、炊飯開始時から米の吸水状態の至適範囲に達するように吸水工程の時間と温度を加減し、米が最適な吸水状態になるように調整したのち炊き上げることで、自動で常に良食味のごはんを得られる炊飯器を提供するものである。
【００１４】
【発明の実施の形態】
請求項１記載の発明は、本体と、前記本体の内部に収納され米と水を入れる鍋と、前記鍋を加熱する加熱手段と、前記本体の外蓋の開放時間を計測する外蓋開放時間計測手段と、前記外蓋開放時間計測手段が一定時間以上の外蓋の開放を計測してから炊飯開始操作が行なわれるまでの時間を予備浸漬時間として測定する予備浸漬時間測定手段と、前記予備浸漬時間測定手段からの出力を入力として前記加熱手段を制御する加熱制御手段を備え、前記加熱制御手段は前記鍋内の米に水を吸水させる吸水工程終了時の米の吸水状態を所定の条件にすべく少なくとも前記吸水工程の時間を加減して、最適な吸水工程を実行するものである。
【００１５】
請求項２記載の発明は、本体と、前記本体の内部に収納され米と水を入れる鍋と、前記鍋を加熱する加熱手段と、前記鍋の温度を測定する鍋温度検知手段と、前記本体の外蓋の開閉を検知する外蓋開閉検知手段と、前記外蓋開閉検知手段が外蓋閉を検知してから炊飯開始操作が行なわれるまでの時間を予備浸漬時間として測定する予備浸漬時間測定手段と、前記鍋温度検知手段からの前記予備浸漬時間の測定中の鍋温度および前記予備浸漬時間測定手段からの予備浸漬時間を入力として前記加熱手段を制御する加熱制御手段を備え、前記加熱制御手段は前記鍋内の米に水を吸水させる吸水工程終了時の米の吸水状態を所定の条件にすべく少なくとも前記吸水工程の時間を加減して最適な吸水工程を実行し、使用者に負担をかけることなく、自動で常に物性の良好なごはんを得ることができるものである。
【００１６】
請求項３記載の発明は、上記請求項１または請求項２の発明において、吸水工程終了時の米の吸水状態を所定の条件にすべく前記吸水工程の温度を加減するものであり、使用者の炊飯前の準備状態を浸水時間と鍋温度から判断し、それに応じて吸水工程の温度を調整することで、使用者に負担をかけることなく、良好な食味のごはんを得ることができる。
【００１７】
請求項４記載の発明は、上記請求項１から３の発明において、炊飯開始時に米の吸水状態が所定の条件を満たしている場合にも、所定温度にて吸水工程を実施するものであり、予備浸漬時の水温のばらつきの影響をなくし、自動で常に安定した食味のごはんを得ることができる。
【００１８】
請求項５の発明は、請求項１〜４の発明において、加熱制御手段が吸水工程において、時間と温度の組み合わせによる複数の工程パターンを持ち、鍋温度検知手段と予備浸漬時間測定手段からの出力より判断し、前記吸水工程終了時の米の吸水状態が所定の一定条件になる最適なひとつのパターンを選択するものであり、使用者に負担をかけることなく自動で常に良好な食味のごはんを得ることができる。
【００１９】
【実施例】
以下、本発明の実施例について図面を参照しながら説明する。
【００２０】
（実施例１）
以下、本発明の第１の実施例について図１、図２で説明する。本体１の内部には着脱自由に収納され米と水を入れる鍋２と、鍋２の底側面部に対向するように配置され、前記鍋２を加熱する加熱手段３を収納して備える。前記本体１の上面開口部には、開閉自在に外蓋５を備える。また、鍋２の底面中央に外接して鍋温度検知手段である鍋センサー４を配置する。
【００２１】
外蓋５の略中央にはマグネット６と、前記マグネット６を回動自在にする傾斜面７と、前記傾斜面７の下端部に前記マグネット６が移動した際に感知するリードスイッチ８を備える。つまり、前記外蓋５の閉鎖時には前記マグネット６は自重で前記傾斜面７を回動して最下端に移動し、前記リードスイッチ８をＯＮする。また前記外蓋５が開放されると、前記マグネット６は前記傾斜面７の最上端に自重で回動し、前記リードスイッチ８から離されてリードスイッチ８がＯＦＦする。
【００２２】
９は前記マグネット６の移動により外蓋５の開放が検知されるとその外蓋開放時間を計測する外蓋開放計時間測手段で有り、前記外蓋開放時間が予め定められた一定時間Ｔｏ以上の時間を計測すると予備浸漬時間測定手段１０で予備浸漬時間を測定開始する。１１は前記予備浸漬時間測定手段１０で予備浸漬時間を測定開始し炊飯開始操作が行われるまでの時間を予備浸漬時間として、この出力により前記加熱手段３を制御する加熱制御手段である。
【００２３】
次に実施例１の動作について図２の第１の実施例の動作プログラムのフローチャートを中心に説明する。
【００２４】
まず、鍋２に米と水を準備してステップ２１で外蓋５を開放するとステップ２２に進み、前記マグネット６が前記傾斜面７の最上端に自重で回動し、前記リードスイッチ８から離されてリードスイッチ８がＯＦＦして外蓋開放時間計測手段９で外蓋開放時間ｔｏの計測が開始される。次に外蓋が閉鎖されるとステップ２３で前記外蓋開放時間ｔｏの測定が完了し、ステップ２４に進む。ステップ２４では前記外蓋開放時間ｔｏが予め定められた一定時間であるＴｏより長い、つまりｔｏ≧Ｔｏかどうかをを判定する。ここではＴｏ＝３秒とし、炊飯準備のための長時間の外蓋の開放か、又は確認のための外蓋の開放（１〜２秒）かを判定する。ｔｏ≧Ｔｏの場合は、つまり本体１内に鍋２が収納されたと判定して、ステップ２５に進み予備浸水時間測定手段１０で予備浸水時間を測定開始する。また、ステップ２４で外蓋開放時間ｔｏが予め定められた一定時間であるＴｏより短い（ｔｏ＜Ｔｏ）と、鍋２のセットが無かった判定して、外蓋５開放の次のタイミングを待つこととなる。
【００２５】
ここで、予備浸水時間の測定開始を鍋２の有無又は鍋２の内容物の有無に係らず、外蓋開放時間ｔｏの時間の長さで判定している為、外蓋５を閉鎖するステップ２３の前で鍋２がセットできていないと、再度外蓋５の開放となり、ステップ２６に進む。ここでも前回のステップ２２と同様にステップ２７で外蓋開放時間ｔｏの測定を開始する。そしてステップ２８で外蓋５が閉鎖されると前記外蓋開放時間ｔｏの測定が完了し、ステップ２９に進む。ステップ２９ではステップ２４と同様に、予め定められた一定時間であるＴｏより長いと本体１内に鍋２が収納されたと判定して、ステップ２５に進み予備浸水時間測定手段１０で前回の予備浸漬時間測定をリセットして新たに予備浸水時間を測定開始する。また、ステップ２９で外蓋開放時間ｔｏが予め定められた一定時間であるＴｏより短いと、鍋２又は鍋２の内容物の確認と判定して、次のステップに進むこととなる。
【００２６】
この後も外蓋５の開放が発生すれば、同様に処理される。
【００２７】
次にステップ３０で本体１に備えた炊飯開始スイッチ（図示せず）をＯＮして炊飯開始となり、ステップ３１で予備浸水時間を測定終了する。
【００２８】
そして、次にステップ３２で前記予備浸水時間を基に吸水工程条件を判定して加熱制御手段１１により加熱手段３を制御して吸水工程を開始する。
【００２９】
次に吸水工程の条件について、図３、図４を用いて説明する。
【００３０】
図３は、精白米の浸漬の水温および時間における吸水率を示したものである。生米の飽和吸水率は３０％前後であるが、水温５℃では２時間以上、２０℃では約１時間、３０℃では約４０分、６０℃では約２０分で飽和状態に達する。また、水温が高いほど飽和吸水率は高くなっているが、これは水温が高い状態が長時間続くと米粒の表面の組織の吸水による膨張が促進されるためである。それよりも高温の６０℃になると、米粒表面の糊化が始まる。糊化とは、安定した構造をもつ生米のベータデンプンに水分と約６０℃以上の熱を加えるとデンプンの結晶構造が崩れ、その間に水の分子が侵入して目の粗い網目構造のアルファデンプンに変化することである。つまり、糊化が始まると吸水率がさらに高くなるのである。ここで、それぞれの浸水温度において飽和状態に吸水した米を炊飯すると、飽和吸水率が高くなるほど、かつ飽和状態に達してからの時間が長いほど粒の表面が崩れ、べちゃべちゃのごはんに炊き上がり、食味が劣る結果となった。
【００３１】
しかし、飽和吸水率が３０％以下の場合は、長時間浸水しても粒の崩れは比較的少なく、食味の劣化は少なかった。以上より、吸水率が３０％を超える場合には、組織の崩壊や糊化など、デンプンの吸水以外の現象が起こっていると考えられる。これらの結果から、粒の中まで火が通り、べたつきが少ない良食味のごはんに炊き上げるためには、吸水率が飽和状態まで達していて、かつ３０％以下の吸水率であることが必要なのである。
【００３２】
また、図４は精白米の浸漬の水温および時間における還元糖量を示したものである。米のデンプンは加水分解されてグルコースなどの還元糖となり、これがごはんの甘み成分となる。つまり、還元糖の多いごはんほど甘く食味が優れているということができる。デンプンの還元糖への分解は、アミラーゼ等の米自身に含まれている酵素の働きを介して起こるため、これら酵素の至適活性温度である４０℃から６０℃で吸水させた場合にもっとも米の甘みが引き出せるのである。
【００３３】
以上２つの結果より、粒がしっかりとして甘味のある良食味のごはんを炊き上げるための浸漬工程の条件は、炊き上げ直前に米の吸水率が飽和状態まで達しており、かつ吸水率３０％以下、かつ水温が４０〜６０℃であることだといえる。よって前記予備浸漬時間測定手段１０により測定された予備浸漬時間により、その不足分について吸水工程で吸水させることとなる。
【００３４】
以上の様に本実施例によれば、外蓋５の開放時間で本体１の鍋２のセットを判定して予備浸漬時間を測定可能とし、例えば、図５に示すように、予備浸漬時間が３０分、吸水工程開始時の鍋底温度が２０℃であった場合、加熱制御手段７は浸漬工程が３０分必要であると判断し、また予備浸漬時間が３０分間、鍋底温度が５℃であった場合には、浸漬工程が９０分間必要であると判断し、加熱手段３がこれを実行した後炊き上げ工程に移行するのである。続く炊き上げ工程では高火力で炊飯し、鍋温度検知手段４が炊き上がり温度を検知した時点で鍋内を均一になじませるむらし工程に移行し、むらし工程では所定時間を経過すると炊飯が終了する。以上一連の操作により、米の吸水不足により芯のあるごはんになったり、浸水しすぎによりべちゃついたごはんになったりすることを防ぎ、使用者に負担をかけることなく、自動で常に物性の良好なごはんを得ることができるのである。
【００３５】
なお、本実施例では外蓋５の開放から閉鎖外蓋開放時間を計測して、定められた一定時間であるＴｏと比較して本体１への鍋２のセット有無を判定して説明したが、外蓋５の開放時間を順次計測し、外蓋５の閉鎖前であっても定められた一定時間であるＴｏを超えた時、本体１への鍋２のセット有りと判定する構成で有っても同様な効果が得られるものである。
【００３６】
（実施例２）
次に、本発明の第２の実施例について説明する。
【００３７】
図６、７図において、１２は外蓋５の閉鎖時にはマグネット６が自重で傾斜面７を回動して最下端に移動し、リードスイッチ８のＯＮを検出し、外蓋５の開放時にはマグネット６が傾斜面７の最上端に自重で回動し、リードスイッチ８から離されてリードスイッチ８のＯＦＦを検出する外蓋開閉検知手段である。その他の本体の構成は実施例１と同じであるため、説明は省略する。
【００３８】
次に実施例２の動作について図７の第２の実施例の動作プログラムのフローチャートを中心に説明する。
【００３９】
まず、鍋２に米と水を準備してステップ４１で外蓋５を開放するとステップ４２に進み、前記マグネット６が前記傾斜面７の最上端に自重で回動し、前記リードスイッチ８から離されてリードスイッチ８がＯＦＦして外蓋開閉検知手段１２で外蓋開閉を検知すると、つまり本体１内に鍋２が収納されたと判定して、予備浸水時間測定手段１０で予備浸水時間を測定開始する。
【００４０】
ここで、予備浸水時間の測定開始を鍋２の有無又は鍋２の内容物の有無に係らず、外蓋開閉で判定している為、外蓋５を閉鎖するステップ４１の前で鍋２が本体１にセットできていないと、再度外蓋５の開放となり、ステップ４３に進む。そして本体１内に鍋２が収納されたと判定して、ステップ４２に進み予備浸水時間測定手段１０で前回の予備浸漬時間測定をリセットして新たに予備浸水時間を測定開始する。この後も外蓋５の開放が発生すれば、同様に処理される。
【００４１】
次にステップ４４で本体１に備えた炊飯開始スイッチ（図示せず）をＯＮして炊飯開始となり、ステップ４５で予備浸水時間を測定終了する。そして、次にステップ４６で前記予備浸水時間及び前記予備浸水時間中の鍋温度検出手段４の温度を基に吸水工程条件を判定して加熱制御手段１１により加熱手段３を制御して吸水工程を開始する。次に吸水工程については実施例１と同様でありその説明を省略する。
【００４２】
以上説明から明らかなように、実施例２によれば例えば、外蓋５の開放により本体１に鍋２をセットしたと判定して予備浸漬時間を測定するとともに、前記予備浸漬時間の測定中の鍋温度を測定可能とし、図５に示すように、予備浸漬時間が３０分、鍋底温度が２０℃であった場合、加熱制御手段７は浸漬工程が３０分必要であると判断し、また予備浸漬時間が３０分間、鍋底温度が５℃であった場合には、浸漬工程が９０分間必要であると判断し、加熱手段３がこれを実行した後炊き上げ工程に移行するのである。続く炊き上げ工程では高火力で炊飯し、鍋温度検知手段４が炊き上がり温度を検知した時点で鍋内を均一になじませるむらし工程に移行し、むらし工程では所定時間を経過すると炊飯が終了する。以上一連の操作により、米の吸水不足により芯のあるごはんになったり、浸水しすぎによりべちゃついたごはんになったりすることを防ぎ、使用者に負担をかけることなく、自動で常に物性の良好なごはんを得ることができるのである。
【００４３】
なお、本実施例では外蓋５の閉鎖時に本体１への鍋２のセットが完了したとして予備浸漬時間測定を開始して説明したが、外蓋５の開放時であっても同様な効果を得る事は言うまでも無い。
【００４４】
また、実施例１及び２において、外蓋５の開放時間を検知するマグネット６、傾斜面７、リードスイッチ８は、炊飯時に発生するおねばをフロートであるマグネット６でキャッチし、おねばが噴出する圧力でマグネット５を移動させる際にリードスイッチ８で検知する構成と兼ねて説明したが、適宜設計変更できる。
【００４５】
（実施例３）
実施例３における本体の構成、および使用者が鍋２を本体１にセットするまでの手段は実施例１と同じであるため、説明は省略する。
【００４６】
まず、使用者が米と水を入れた鍋２を本体１にセットし、外蓋５を閉じると外蓋開放時間測定手段９が外蓋５の閉を検知し、予備浸漬時間測定手段１０が予備浸漬時間の測定を開始する。同時に、鍋温度測定手段４が鍋内の予備浸漬温度として鍋底温度の測定を開始する。
【００４７】
次に使用者が炊飯を開始した時点で予備浸漬時間測定手段１０および鍋温度測定手段４は測定を終了し、予備浸漬時間を算出し、鍋温度測定手段は予備浸漬温度を算出する。加熱制御手段１１には予め、前述の実験データより時間と水温と吸水率に関する推定式を持たせておき、予備浸漬時間と予備浸漬温度から炊飯開始時の米の吸水率を推定する。炊飯開始と同時に始まる吸水工程では、制御手段は推定された吸水率と予備浸漬時間と鍋底温度から判断して、米の吸水率が飽和状態まで達し、かつ吸水率３０％以下、かつ水温が４０〜６０℃になるように加熱手段３を制御し、この状態に達した時点で吸水工程を終了する。
【００４８】
例えば、図８に示すように、予備浸漬時間が３０分、鍋底温度が２０℃であった場合、加熱制御手段は浸漬工程が鍋底温度５０℃で１０分間必要であると判断し、また予備浸漬時間が３０分、鍋底温度が５℃であった場合には、浸漬工程が鍋底温度５０℃で２０分間必要であると判断し、加熱手段がこれを実行した後炊き上げ工程に移行するのである。続く炊き上げ工程では高火力で炊飯し、鍋温度検知手段４が炊き上がり温度を検知した時点で鍋内を均一になじませるむらし工程に移行し、むらし工程では所定時間を経過すると炊飯が終了する。以上一連の操作により、使用者に負担をかけることなく、米の吸水不足により芯のあるごはんになったり、浸水しすぎによりべちゃついたごはんになったりすることを防ぎ、かつ米に含まれる酵素を活性化し、甘味に優れたごはんを得ることができるのである。
【００４９】
（実施例４）
実施例４における本体の構成は実施例１および２と同じであるため、説明は省略する。実施例１および２における炊飯動作と同様に、加熱制御手段１１が予備浸漬時間と予備浸漬温度から炊飯開始時の米の吸水率を推定するが、炊飯開始時の米の吸水率がすでに所定の条件に達していると判断された場合にも、加熱制御手段１１は一定時間、水温が４０〜６０℃になるように加熱手段３を制御する。図９に示す例では、予備浸漬時間が６０分、鍋底温度が２０℃であった場合、および予備浸漬時間が１２０分、鍋底温度が５℃であった場合には、いずれも米の吸水状態は飽和に達していると判断するが、どちらの場合においても加熱制御手段１１は浸漬工程を鍋底温度５０℃で５分間実行するように加熱手段３を制御する。その後炊き上げ工程とむらし工程に移行し、ごはんを炊き上げるのである。この操作により、予備浸水時の水温のばらつきの影響をなくし、予備浸漬の状態に関わらず、常に安定した食味のごはんを得ることができるのである。
【００５０】
（実施例５）
実施例５における本体の構成は実施例１および２と同じであるため、説明は省略する。実施例３における炊飯動作と同様に、加熱制御手段１１が予備浸漬時間と予備浸漬温度から炊飯開始時の米の吸水率を推定するが、予め加熱制御手段１１に、特に物性と甘味のバランスがとれた良好な食味のごはんが得られる吸水時間と温度の組合せの複数の工程パターンを持たせておき、炊飯開始時の吸水条件に最も適した吸水工程パターンをその中から選択して実行することにより、自動で常に触感と甘味のバランスの取れた良好な食味のごはんを得ることができるのである。
【００５１】
なお、以上の実施例１から５は、マイコンにより制御されるその他の方式の炊飯器においても実施可能であることは言うまでも無い。
【００５２】
また、本実施例における精白米の浸漬の水温および時間における吸水率および還元糖量とその結果から導き出せる所定の吸水条件は、精白米品種にコシヒカリを用いた一例であり、米の品種や状態によって適宜調整することができる。
【００５３】
【発明の効果】
以上のように、請求項１記載の発明によれば、使用者の炊飯前の鍋セットを外蓋開放時間から判定し、外蓋開放時間に応じて予備浸漬時間を測定して炊飯開始後に最適な時間の吸水工程を実行することで、芯のないごはんに炊き上げる一方、ごはんの崩れやべちゃつきを防ぎ、自動で常に、物性の良好なごはんを得ることができる。
【００５４】
請求項２記載の発明によれば、使用者の炊飯前の鍋セットを外蓋の開閉で判定し、外蓋の開閉に応じて予備浸漬時間を測定するとともに、予備浸漬時間測定中の鍋温度を検知し、予備浸漬時間と鍋温度から判断し、それに応じた最適な時間の吸水工程を実行することで、芯のないごはんに炊き上げる一方、ごはんの崩れやべちゃつきを防ぎ、自動で常に、物性の良好なごはんを得ることができる。
【００５５】
また、請求項３記載の発明によれば、使用者の炊飯前の準備状態を浸水時間と鍋温度から判断し、それに応じて吸水工程の温度を調整することで、米の甘味を引き出し、自動で常に、特に甘味に優れた良好な食味のごはんを得ることができる。
【００５６】
また、請求項４記載の発明によれば、炊飯開始時に米の吸水状態が飽和状態に達していても、所定温度の吸水工程を実施することで、予備浸漬時の水温のばらつきの影響をなくし、自動で常に安定した食味のごはんを得ることができる。
【００５７】
また、請求項５記載の発明によれば、加熱制御手段が吸水工程にて時間と温度の組み合わせによる複数の工程パターンを持ち、吸水工程終了時の米の吸水状態が所定の一定条件になる最適なひとつを選択することにより、自動で常に触感と甘味のバランスの取れた良好な食味のごはんを得ることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施例を示す炊飯器のブロック図
【図２】同第１の実施例の動作プログラムのフローチャート
【図３】精白米の浸漬の水温および時間における吸水率を示した図
【図４】精白米の浸漬の水温および時間における還元糖量を示した図
【図５】本発明の第１及び２の実施の形態における炊飯工程を示す図
【図６】本発明の第２の実施例を示す炊飯器のブロック図
【図７】同第２の実施例の動作プログラムのフローチャート
【図８】本発明の第３の実施の形態における炊飯工程を示す図
【図９】本発明の第４の実施の形態における炊飯工程を示す図
【符号の説明】
１本体
２鍋
３加熱手段
４鍋温度検知手段
５外蓋
６マグネット
７傾斜面
８リードスイッチ
９外蓋開放時間計測手
１０予備浸漬時間測定手段
１１加熱制御手段
１２外蓋開閉検知手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rice cooker mainly used for home use.
[0002]
[Prior art]
Generally, it is known that rice can be cooked after sufficient water is added to rice to obtain delicious rice. The water absorption step at the time of cooking rice is a step in which rice absorbs water at a temperature equal to or lower than the gelatinization temperature of rice (60 to 70 ° C.), and can also be referred to as a preheating step. Rice has a water content of about 15% in the state of polished rice, but when absorbed to a saturated state, the water content becomes about 30%. In general, the higher the immersion temperature, the shorter the time to reach the saturated state is 2 hours or more at a water temperature of 5 ° C., about 1 hour at a water temperature of 20 ° C., and about 20 minutes at a water temperature of 60 ° C. When rice that has absorbed water in a saturated state is cooked, moisture and heat spread to the center of the rice grains, and rice with a good taste without a core is cooked.
[0003]
In a rice cooker controlled by a current microcomputer, applying this principle, a water absorption process for 20 minutes at a high temperature of 40 to 50 ° C. is performed, and after absorbing water in a short time, the rice is cooked. The rice cooker is heated after absorbing water for a certain time at a temperature lower than the gelatinization temperature of rice (for example, see Patent Document 1).
[0004]
In some cases, the immersion time is adjusted according to the amount of cooked rice (for example, see Patent Document 2).
[0005]
In some cases, a plurality of immersion times are stored so that a user can select one according to the situation (for example, see Patent Document 3).
[0006]
[Patent Document 1]
JP-B-59-24815
[Patent Document 2]
JP-B-63-46884
[Patent Document 3]
JP-A-3-30731
[0007]
[Problems to be solved by the invention]
However, as a usage of the user, there are not a few cases where the water is immersed in advance before the rice cooking is started. If the rice soaked to the saturated state is further soaked at a high temperature, the texture of the rice surface is broken, the rice becomes sticky, and the taste is inferior. That is, an operation performed by the user to improve the taste may result in a decrease in the taste. In such a case, the problem can be solved if the user operates the rice cooker and does not have a water absorption process or chooses a shortened course, but the judgment is left to the user and the device automatically cooks the food automatically and optimally I couldn't do that.
[0008]
In addition, although the immersion time until saturation varies depending on the water temperature, it is difficult for a user to judge the water temperature and the optimal immersion time in daily cooking, and it is difficult for everyone to cook the most delicious food under the optimal conditions at all times. Was.
[0009]
The present invention has been made in order to solve the above-described problems, and determines a user's preparation state before rice cooking from a water immersion time and a pot temperature, and executes an optimal water absorption process according to the water use. It is an object of the present invention to provide a rice cooker capable of automatically and always obtaining good-tasting rice without putting a burden on a person.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a main body, a pot that is stored inside the main body and puts rice and water, a heating unit that heats the pan, and an outer lid opening / closing detection unit that detects an outer lid opening / closing unit. Pre-immersion time measuring means for measuring the time from when the outer lid opening time measuring means measures the opening time of the outer lid for a predetermined time or more to when the rice cooking start operation is performed as a pre-immersion time, and a pan temperature detecting means, Equipped with heating control means that controls the heating means using the output from the pre-immersion time measuring means as input, measures the time from when the pot containing rice and water is stored inside the main unit to when the user starts cooking rice Further, the water absorption state of the rice is calculated from the pot temperature by the pan temperature detection means, and the heating control means adjusts the water absorption process from the state to a predetermined optimum water absorption state.
[0011]
The predetermined optimal water absorption state is based on an event uniquely found as a result of earnest research. That is, the correlation between the water absorption state of rice and the taste of cooked rice. In water absorption of rice, the time to reach the saturated water absorption is shorter as the water temperature is higher, but if the saturated water absorption state continues for a long time, the rice surface will collapse or the rice will begin to gelatinize, so the taste is poor when cooked. Would.
[0012]
In addition, reducing sugar, which is the sweetness of rice, which is a factor of sweetness, is generated more as the temperature of immersion water is higher and the time is longer.However, if this state continues for a long time, the surface of the rice may collapse or the rice may become glued. The taste of rice cooked is inferior because it starts to change. From these events, it can be said that the relationship between rice immersion temperature and time is correlated with the texture and sweetness of cooked rice, that is, the taste. In other words, there is an optimal range of the water absorption state of rice for cooking good-quality rice, which can be replaced by the conditions of rice immersion temperature and time.
[0013]
In the present invention, the user prepares for cooking, that is, measures the time and temperature from the time when the pot containing rice and water is set in the rice cooker to the time when the rice starts to be cooked, and the heating control means determines the water absorption state of the rice from the result. Calculate, adjust the time and temperature of the water absorption process to reach the optimal range of the water absorption state of rice from the start of rice cooking, adjust the rice to the optimal water absorption state, and cook it automatically, always automatically The purpose of the present invention is to provide a rice cooker from which good-quality rice can be obtained.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1, wherein the main body, a pot stored inside the main body to put rice and water, a heating means for heating the pan, and an outer lid opening time for measuring an opening time of the outer lid of the main body. A pre-soaking time measuring means for measuring the time from when the outer cover opening time measuring means measures the opening of the outer cover for a predetermined time or more to when the rice cooking start operation is performed as a pre-soaking time, and Heating control means for controlling the heating means by using an output from the immersion time measuring means as an input, wherein the heating control means determines a water absorption state of the rice at the end of a water absorption step of absorbing water in the rice in the pan under a predetermined condition. At least the time of the water absorption step is adjusted so that the optimum water absorption step is performed.
[0015]
The invention according to claim 2, wherein the main body, a pot stored inside the main body to put rice and water, a heating means for heating the pan, a pot temperature detecting means for measuring the temperature of the pan, the main body Outer lid opening / closing detecting means for detecting the opening / closing of the outer lid, and pre-soaking time measurement for measuring a time from when the outer lid opening / closing detecting means detects the outer lid closing to when the rice cooking start operation is performed as a pre-soaking time. Means, and a heating control means for controlling the heating means with the pot temperature during the measurement of the preliminary immersion time from the pan temperature detection means and the preliminary immersion time from the preliminary immersion time measurement means as inputs, and the heating control The means performs an optimal water absorption step by adjusting at least the time of the water absorption step to adjust the water absorption state of the rice at the end of the water absorption step of causing the rice in the pot to absorb water to a predetermined condition, and bears the burden on the user. Without applying In those which can always obtain good rice properties.
[0016]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the temperature of the water absorption step is adjusted so that the water absorption state of rice at the end of the water absorption step is set to a predetermined condition. By judging the preparation state before cooking rice from the water immersion time and the pot temperature, and adjusting the temperature of the water absorption step accordingly, a good-tasting rice can be obtained without imposing a burden on the user.
[0017]
According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the water absorption step is performed at a predetermined temperature even when the water absorption state of the rice satisfies a predetermined condition at the start of rice cooking, Eliminating the effects of water temperature variations during pre-soaking, it is possible to automatically and always obtain stable-tasting rice.
[0018]
According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the heating control means has a plurality of process patterns based on a combination of time and temperature in the water absorption step, and outputs from the pot temperature detecting means and the preliminary immersion time measuring means. Judgment is made to select one optimal pattern in which the water absorption state of rice at the end of the water absorption step becomes a predetermined constant condition, and automatically provide a rice with good taste automatically without burdening the user. Obtainable.
[0019]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
(Example 1)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. Inside the main body 1, there is provided a pot 2, which is freely detachably accommodated and is for putting rice and water, and a heating means 3 for heating the pot 2, which is arranged to face the bottom side of the pot 2. An outer lid 5 is provided at the top opening of the main body 1 so as to be freely opened and closed. Further, a pan sensor 4 serving as a pan temperature detecting means is arranged at the center of the bottom of the pan 2 so as to circumscribe.
[0021]
At the approximate center of the outer lid 5, there are provided a magnet 6, an inclined surface 7 for allowing the magnet 6 to rotate freely, and a reed switch 8 at the lower end of the inclined surface 7 for sensing when the magnet 6 moves. That is, when the outer lid 5 is closed, the magnet 6 rotates on the inclined surface 7 by its own weight, moves to the lowermost end, and turns on the reed switch 8. When the outer lid 5 is opened, the magnet 6 rotates to the uppermost end of the inclined surface 7 by its own weight, is separated from the reed switch 8, and the reed switch 8 is turned off.
[0022]
Reference numeral 9 denotes an outer cover open time measuring means for measuring the outer cover open time when the opening of the outer cover 5 is detected by the movement of the magnet 6, and the outer cover open time is equal to or longer than a predetermined time To. Is measured, the preliminary immersion time measuring means 10 starts measuring the preliminary immersion time. Reference numeral 11 denotes heating control means for controlling the heating means 3 by the output, with the time from when the preliminary immersion time measuring means 10 starts measuring the preliminary immersion time to when the rice cooking start operation is performed as the preliminary immersion time.
[0023]
Next, the operation of the first embodiment will be described focusing on the flowchart of the operation program of the first embodiment in FIG.
[0024]
First, rice and water are prepared in the pot 2 and when the outer lid 5 is opened in step 21, the process proceeds to step 22, where the magnet 6 rotates to the uppermost end of the inclined surface 7 by its own weight and separates from the reed switch 8. Then, the reed switch 8 is turned off, and the measurement of the outer lid opening time to is started by the outer lid opening time measuring means 9. Next, when the outer lid is closed, the measurement of the outer lid opening time to is completed in step 23, and the process proceeds to step 24. In step 24, it is determined whether the outer lid opening time to is longer than a predetermined fixed time To, that is, whether to ≧ To. Here, To = 3 seconds, and it is determined whether the outer lid is opened for a long time for rice cooking preparation or the outer lid is opened (1-2 seconds) for confirmation. If to ≧ To, that is, it is determined that the pot 2 has been stored in the main body 1, the process proceeds to step 25, and the preliminary flooding time measuring means 10 starts measuring the preliminary flooding time. When the outer lid opening time to is shorter than the predetermined fixed time To (to <To) in step 24, it is determined that the pan 2 has not been set, and the next timing of opening the outer lid 5 is waited. It will be.
[0025]
Here, since the start of the measurement of the pre-immersion time is determined by the length of the outer lid opening time to regardless of the presence or absence of the pan 2 or the contents of the pan 2, the step of closing the outer lid 5 If the pan 2 has not been set before 23, the outer lid 5 is opened again, and the process proceeds to step 26. Here also, the measurement of the outer lid opening time to is started in step 27 as in the previous step 22. When the outer lid 5 is closed in step 28, the measurement of the outer lid opening time to is completed, and the process proceeds to step 29. In step 29, similarly to step 24, if the predetermined time is longer than To, which is a predetermined time, it is determined that the pot 2 has been stored in the main body 1, and the process proceeds to step 25, where the preliminary immersion time measuring means 10 performs the previous preliminary immersion. The time measurement is reset and a new pre-immersion time measurement is started. If the outer lid opening time to is shorter than the predetermined fixed time To in step 29, it is determined that the pot 2 or the contents of the pot 2 is to be confirmed, and the process proceeds to the next step.
[0026]
After that, if the outer lid 5 is opened, the same processing is performed.
[0027]
Next, in step 30, the rice cooker start switch (not shown) provided in the main body 1 is turned on to start rice cooker, and in step 31, the measurement of the pre-immersion time is completed.
[0028]
Then, in step 32, the conditions of the water absorption step are determined based on the preliminary water immersion time, and the heating control means 11 controls the heating means 3 to start the water absorption step.
[0029]
Next, the conditions of the water absorption step will be described with reference to FIGS.
[0030]
FIG. 3 shows the water absorption at the water temperature and time of immersion of the polished rice. The saturated water absorption of raw rice is about 30%, but reaches a saturated state in 2 hours or more at a water temperature of 5 ° C, about 1 hour at 20 ° C, about 40 minutes at 30 ° C, and about 20 minutes at 60 ° C. The higher the water temperature, the higher the saturated water absorption. This is because if the water temperature is high for a long time, the expansion of the tissue of the surface of the rice grain due to water absorption is promoted. At a higher temperature of 60 ° C., gelatinization of the rice grain surface starts. Gelatinization means that when water and heat of about 60 ° C or more are added to raw rice beta starch having a stable structure, the crystalline structure of the starch collapses, during which water molecules penetrate and the alpha of the coarse network structure Is to turn into starch. That is, when gelatinization starts, the water absorption rate further increases. Here, when the rice that has absorbed water in a saturated state at each immersion temperature is cooked, the surface of the grains collapses as the saturated water absorption rate becomes higher and the time after reaching the saturated state becomes longer, and the rice is cooked. After cooking, the taste was inferior.
[0031]
However, when the saturated water absorption was 30% or less, the collapse of the particles was relatively small even when the water was immersed for a long time, and the deterioration of taste was small. From the above, when the water absorption exceeds 30%, it is considered that phenomena other than the water absorption of starch have occurred, such as collapse of the structure and gelatinization. From these results, it is necessary that the water absorption rate reaches a saturated state and the water absorption rate is 30% or less in order to cook a good-tasting rice with a low stickiness and a fire passing through the inside of the grains. is there.
[0032]
FIG. 4 shows the amount of reducing sugar at the water temperature and time of immersion of the polished rice. Rice starch is hydrolyzed into reducing sugars such as glucose, which is a sweet component of rice. In other words, it can be said that rice with a large amount of reducing sugar is sweet and has excellent taste. Degradation of starch into reducing sugars occurs through the action of enzymes contained in the rice itself, such as amylase. Therefore, when water is absorbed at 40 ° C to 60 ° C, which is the optimal activity temperature of these enzymes, rice is most likely to be degraded. Can bring out the sweetness.
[0033]
According to the above two results, the conditions of the immersion step for cooking rice with a firm grain and sweet taste are that the water absorption of rice reaches a saturated state immediately before cooking and the water absorption is 30% or less. It can be said that the water temperature is 40 to 60C. Therefore, based on the preliminary immersion time measured by the preliminary immersion time measuring means 10, the shortage is absorbed in the water absorption step.
[0034]
As described above, according to the present embodiment, the pre-immersion time can be measured by determining the setting of the pot 2 of the main body 1 based on the opening time of the outer lid 5. For example, as shown in FIG. If the pot bottom temperature at the start of the water absorption step is 20 ° C. for 30 minutes, the heating control means 7 determines that the immersion step is required for 30 minutes, and the preliminary immersion time is 30 minutes and the pot bottom temperature is 5 ° C. In this case, it is determined that the immersion step is necessary for 90 minutes, and the heating means 3 executes the immersion step, and then shifts to the cooking step. In the subsequent cooking process, rice is cooked with high heat, and when the pot temperature detecting means 4 detects the cooked temperature, the process shifts to a uniform process in which the inside of the pan is uniformly blended. finish. By the above series of operations, it is possible to prevent the rice from becoming cored due to insufficient water absorption of rice, and from becoming too sticky due to excessive water infiltration, and automatically apply physical properties without burdening the user. You can get good rice.
[0035]
In the present embodiment, the closed outer lid opening time is measured from the opening of the outer lid 5 and compared with To which is a predetermined fixed time, and it is determined whether the pan 2 is set on the main body 1 or not. , The opening time of the outer lid 5 is sequentially measured, and it is determined that the pan 2 is set on the main body 1 when the time exceeds a predetermined fixed time To even before the outer lid 5 is closed. However, the same effect can be obtained.
[0036]
(Example 2)
Next, a second embodiment of the present invention will be described.
[0037]
6 and 7, reference numeral 12 denotes a magnet when the outer lid 5 is closed, the magnet 6 rotates on the inclined surface 7 by its own weight and moves to the lowermost end, and detects that the reed switch 8 is ON. Numeral 6 is an outer lid opening / closing detecting means which turns to the uppermost end of the inclined surface 7 by its own weight, is separated from the reed switch 8 and detects the OFF of the reed switch 8. The other configuration of the main body is the same as that of the first embodiment, and the description is omitted.
[0038]
Next, the operation of the second embodiment will be described with reference to the flowchart of the operation program of the second embodiment in FIG.
[0039]
First, when rice and water are prepared in the pot 2 and the outer lid 5 is opened in step 41, the process proceeds to step 42, where the magnet 6 is rotated by its own weight to the uppermost end of the inclined surface 7 and separated from the reed switch 8. Then, when the reed switch 8 is turned off and the outer lid opening / closing detecting means 12 detects the opening / closing of the outer lid, that is, it is determined that the pot 2 is stored in the main body 1, and the preliminary flooding time measuring means 10 measures the preliminary flooding time. Start.
[0040]
Here, since the start of the measurement of the pre-immersion time is determined by opening and closing the outer lid regardless of the presence or absence of the pan 2 or the content of the pan 2, the pan 2 is closed before the step 41 of closing the outer lid 5. If it is not set on the main body 1, the outer lid 5 is opened again, and the process proceeds to step 43. Then, it is determined that the pot 2 is stored in the main body 1, and the process proceeds to step 42, where the preliminary preliminary immersion time measurement unit 10 resets the previous preliminary immersion time measurement and newly starts the preliminary preliminary immersion time measurement. After that, if the outer lid 5 is opened, the same processing is performed.
[0041]
Next, in step 44, a rice cook start switch (not shown) provided in the main body 1 is turned on to start rice cooking, and in step 45, the measurement of the pre-immersion time is completed. Then, in step 46, the conditions of the water absorption step are determined based on the pre-immersion time and the temperature of the pot temperature detecting means 4 during the pre-immersion time, and the heating control means 11 controls the heating means 3 to execute the water absorption step. Start. Next, the water absorption step is the same as in Example 1, and the description thereof is omitted.
[0042]
As is clear from the above description, according to the second embodiment, for example, it is determined that the pot 2 is set on the main body 1 by opening the outer lid 5, and the preliminary immersion time is measured. The pot temperature can be measured, and as shown in FIG. 5, when the preliminary immersion time is 30 minutes and the pan bottom temperature is 20 ° C., the heating control means 7 determines that the immersion step is required for 30 minutes. If the immersion time is 30 minutes and the pot bottom temperature is 5 ° C., it is determined that the immersion step is necessary for 90 minutes, and the heating means 3 executes this and shifts to the cooking step. In the subsequent cooking process, rice is cooked with high heat, and when the pot temperature detecting means 4 detects the cooked temperature, the process shifts to a uniform process in which the inside of the pan is uniformly blended. finish. By the above series of operations, it is possible to prevent the rice from becoming cored due to insufficient water absorption of rice, and from becoming too sticky due to excessive water infiltration, and automatically apply physical properties without burdening the user. You can get good rice.
[0043]
In the present embodiment, the preliminary immersion time measurement is described assuming that the setting of the pot 2 on the main body 1 is completed when the outer lid 5 is closed, but the same effect is obtained even when the outer lid 5 is opened. Needless to say, I get it.
[0044]
Further, in the first and second embodiments, the magnet 6, which detects the opening time of the outer lid 5, the inclined surface 7, and the reed switch 8 catch the rice generated during the rice cooking with the magnet 6, which is a float, and the rice is ejected. In the above description, the reed switch 8 detects the movement of the magnet 5 when the magnet 5 is moved at a given pressure.
[0045]
(Example 3)
The configuration of the main body according to the third embodiment and the means until the user sets the pan 2 on the main body 1 are the same as those of the first embodiment, and thus description thereof is omitted.
[0046]
First, when the user sets the pot 2 containing rice and water in the main body 1 and closes the outer lid 5, the outer lid opening time measuring means 9 detects the closing of the outer lid 5 and the preliminary immersion time measuring means 10 Start measuring the pre-immersion time. At the same time, the pan temperature measuring means 4 starts measuring the pan bottom temperature as the pre-immersion temperature in the pan.
[0047]
Next, when the user starts cooking rice, the preliminary immersion time measuring means 10 and the pan temperature measuring means 4 end the measurement, calculate the preliminary immersion time, and the pan temperature measuring means calculates the preliminary immersion temperature. The heating control means 11 is preliminarily provided with an estimation formula relating to time, water temperature and water absorption based on the above-mentioned experimental data, and estimates the water absorption of rice at the start of rice cooking from the pre-soaking time and pre-soaking temperature. In the water absorption step which starts simultaneously with the start of rice cooking, the control means judges the water absorption rate of the rice to a saturated state, the water absorption rate is 30% or less, and the water temperature is 40, judging from the estimated water absorption rate, the preliminary immersion time and the pot bottom temperature. The heating means 3 is controlled so as to reach ６０60 ° C., and when this state is reached, the water absorption step is ended.
[0048]
For example, as shown in FIG. 8, when the preliminary immersion time is 30 minutes and the pan bottom temperature is 20 ° C., the heating control means determines that the immersion step is required at the pan bottom temperature of 50 ° C. for 10 minutes, and If the time is 30 minutes and the pan bottom temperature is 5 ° C., it is determined that the immersion step is necessary at the pan bottom temperature of 50 ° C. for 20 minutes, and the heating means executes this, and then proceeds to the cooking step. . In the subsequent cooking process, rice is cooked with high heat, and when the pot temperature detecting means 4 detects the cooked temperature, the process shifts to a uniform process in which the inside of the pan is uniformly blended. finish. By the above series of operations, without putting a burden on the user, it is possible to prevent the rice from becoming a cored rice due to insufficient water absorption and from becoming a sticky rice due to excessive flooding, and contained in rice By activating the enzyme, rice with excellent sweetness can be obtained.
[0049]
(Example 4)
The configuration of the main body according to the fourth embodiment is the same as that of the first and second embodiments, and a description thereof will be omitted. Similar to the rice cooking operation in Examples 1 and 2, the heating control means 11 estimates the water absorption of rice at the start of rice cooking from the pre-immersion time and the pre-immersion temperature. Even when it is determined that the condition has been reached, the heating control means 11 controls the heating means 3 so that the water temperature becomes 40 to 60 ° C. for a certain time. In the example shown in FIG. 9, when the preliminary immersion time was 60 minutes and the pan bottom temperature was 20 ° C., and when the preliminary immersion time was 120 minutes and the pan bottom temperature was 5 ° C., the water absorption state of the rice was all Is determined to have reached saturation, but in either case, the heating control means 11 controls the heating means 3 so as to execute the immersion step at a pot bottom temperature of 50 ° C. for 5 minutes. After that, it shifts to the cooking process and the steaming process, where the rice is cooked. By this operation, it is possible to eliminate the influence of the variation of the water temperature at the time of the preliminary immersion, and to obtain rice with a stable taste regardless of the state of the preliminary immersion.
[0050]
(Example 5)
The configuration of the main body according to the fifth embodiment is the same as that of the first and second embodiments, and a description thereof will be omitted. Similar to the rice cooking operation in the third embodiment, the heating control means 11 estimates the water absorption of rice at the start of rice cooking from the pre-soaking time and the pre-soaking temperature. Having multiple process patterns of the combination of water absorption time and temperature to obtain good-tasting rice, select and execute the water absorption process pattern most suitable for the water absorption conditions at the start of rice cooking As a result, it is possible to automatically and always obtain good-tasting rice with a good balance between touch and sweetness.
[0051]
Needless to say, Embodiments 1 to 5 described above can be implemented in other types of rice cookers controlled by a microcomputer.
[0052]
In addition, the predetermined water absorption conditions that can be derived from the water absorption rate and the amount of reducing sugar at the water temperature and time of immersion of the polished rice in the present example and the result are examples of using Koshihikari as a polished rice variety, and depending on the variety and state of the rice. It can be adjusted appropriately.
[0053]
【The invention's effect】
As described above, according to the first aspect of the present invention, the pan set before cooking by the user is determined from the open time of the outer lid, the pre-immersion time is measured according to the open time of the outer lid, and the optimal time after the start of rice cooking. Executing the water absorption process for a short time makes it possible to cook rice without a core while preventing the rice from collapsing and sticking, and to automatically obtain a rice with good physical properties.
[0054]
According to the invention described in claim 2, the pan set before cooking by the user is determined by opening and closing the outer lid, the pre-immersion time is measured according to the opening and closing of the outer lid, and the pot temperature during the pre-immersion time measurement is measured. By judging from the preliminary immersion time and the pot temperature and executing the water absorption process at the optimal time according to that, while cooking rice without a core, it prevents rice from collapsing and sticking, and automatically You can always get good-quality rice.
[0055]
According to the third aspect of the present invention, the user's preparation state before cooking is judged from the water immersion time and the pot temperature, and the temperature of the water absorption step is adjusted accordingly, thereby extracting the sweetness of the rice and automatically In particular, it is possible to always obtain good-tasting rice with excellent sweetness.
[0056]
According to the fourth aspect of the present invention, even if the water absorption state of the rice has reached a saturated state at the start of rice cooking, the water absorption step at a predetermined temperature is performed to eliminate the influence of the water temperature variation at the time of preliminary immersion. Automatically, you can always get rice with stable taste.
[0057]
According to the fifth aspect of the present invention, the heating control means has a plurality of process patterns based on a combination of time and temperature in the water absorbing step, and the rice water absorbing state at the end of the water absorbing step is a predetermined constant condition. By selecting one, it is possible to automatically obtain a good-tasting rice with a good balance between touch and sweetness.
[Brief description of the drawings]
FIG. 1 is a block diagram of a rice cooker showing a first embodiment of the present invention.
FIG. 2 is a flowchart of an operation program according to the first embodiment;
FIG. 3 is a diagram showing the water absorption rate at the water temperature and time of immersion of milled rice.
FIG. 4 is a diagram showing the amount of reducing sugar at the water temperature and time of immersion of milled rice
FIG. 5 is a diagram showing a rice cooking process in the first and second embodiments of the present invention.
FIG. 6 is a block diagram of a rice cooker according to a second embodiment of the present invention.
FIG. 7 is a flowchart of an operation program according to the second embodiment.
FIG. 8 is a diagram showing a rice cooking process according to a third embodiment of the present invention.
FIG. 9 is a diagram showing a rice cooking process according to a fourth embodiment of the present invention.
[Explanation of symbols]
1 body
2 pots
3 heating means
4 Pot temperature detection means
5 outer lid
6 magnets
7 Slope
8 Reed switch
9 Hands measuring outer lid opening time
10 Pre-immersion time measuring means
11 Heating control means
12 Outer lid open / close detection means

Claims

A main body, a pot stored inside the main body for putting rice and water, heating means for heating the pan, outer lid opening time measuring means for measuring an opening time of the outer lid of the main body, and opening the outer lid Preliminary immersion time measuring means for measuring the time from the opening of the outer lid for a predetermined time or more to the start of the rice cooking operation as a preliminary immersion time, and an output from the preliminary immersion time measuring means. Heating control means for controlling the heating means as an input, the heating control means at least in the water absorption step to set the water absorption state of the rice at the end of the water absorption step of absorbing water in the rice in the pot to a predetermined condition A rice cooker that adjusts time.

A main body, a pot housed inside the main body for putting rice and water, a heating means for heating the pan, a pot temperature detecting means for measuring the temperature of the pan, and detecting opening and closing of an outer lid of the main body. Outer lid opening / closing detecting means, pre-soaking time measuring means for measuring a time from when the outer lid opening / closing detecting means detects the outer lid closing to when the rice cooking start operation is performed as a pre-soaking time, and the pan temperature detecting means And heating control means for controlling the heating means by inputting the pre-soaking time from the pre-soaking time measurement means and the pre-soaking time from the pre-soaking time measuring means, wherein the heating control means controls the rice in the pan. A rice cooker in which at least the time of the water absorption step is adjusted so that the water absorption state of rice at the end of the water absorption step for absorbing water is set to a predetermined condition.

The rice cooker according to claim 1 or 2, wherein the temperature of the water absorption step is adjusted so that the water absorption state of the rice at the end of the water absorption step is set to a predetermined condition.

The rice cooker according to any one of claims 1 to 3, wherein the water absorption step is performed at a predetermined temperature even when the water absorption state of the rice satisfies a predetermined condition at the start of rice cooking.

The heating control means has a plurality of process patterns based on a combination of time and temperature in the water absorption step, and judges from the outputs from the pot temperature detection means and the preliminary immersion time measurement means, and the water absorption state of the rice at the end of the water absorption step. The rice cooker according to any one of claims 1 to 5, wherein one optimal pattern that satisfies predetermined conditions is selected.