JP3818779B2

JP3818779B2 - How to make quick-cooked rice

Info

Publication number: JP3818779B2
Application number: JP21503698A
Authority: JP
Inventors: 史泰牧原; 茂久三浦; 貴司荒川
Original assignee: QP Corp
Current assignee: QP Corp
Priority date: 1998-07-30
Filing date: 1998-07-30
Publication date: 2006-09-06
Anticipated expiration: 2018-07-30
Also published as: JP2000041599A

Description

【０００１】
【発明の属する技術分野】
本発明は、早炊き米の製造方法に関する。
【０００２】
【従来の技術】
通常の炊飯米やおこわなどを製する際に行われている水洗いや水浸漬などの前処理が不要で、しかも通常の炊飯や蒸しに要する時間より早い時間で炊く（蒸らしも含む）ことができる加工米として早炊き米が知られており、近年、このように簡便に炊くことができることからその需要が延びている。
従来の早炊き米の製造方法としては、例えば、特開平１−３０４８５６号公報記載のように浸漬処理米を生蒸気で蒸煮処理後、真空冷却により２５℃程度に急速冷却し、次に１〜２日間熟成し、ほぐして単粒化した後、袋詰めする方法、また特開平７−３１５４０号公報記載のように浸漬処理米を定量フィーダー装着の蒸煮装置を用い生蒸気で蒸煮処理し、得られた蒸煮米を一定量袋に入れた後、真空冷却包装装置で急速冷却するとともに密封し、次に１〜２日間熟成した後、ほぐして単粒化する方法などが知られている。
【０００３】
しかしながら、上述の従来の製造方法は、何れも１〜２日間の熟成工程を要し生産効率に問題があった。
さりとて、熟成工程を行わずほぐすことも考えられるが、上述の熟成工程前の米飯の状態は、生蒸気で蒸煮処理するためか米粒表面が湿潤で粘り気を有し、米粒同士が結着し易い状態であった。また定量フィーダーによる強制排出、その後の真空冷却による瞬時の冷却により、粘り気を有した米粒同士がより強固に結着し塊状となっていた。そのため、熟成工程前の米飯をほぐして容易に単粒化することは難しく、ほぐせたとしても得られた早炊き米は、ほぐし工程由来の破米を多く含んだものとなり商品価値を損なう傾向にあった。
さらに、上述の従来法は、冷却を真空状態で行っているためか得られた早炊き米は、炊飯したときの食味が通常の炊飯米と同程度の食味を有しているとは言い難いものであった。
【０００４】
【発明が解決しようとする課題】
そこで、本発明の目的は、商品価値を損なうことなく効率的に早炊き米を製造することができ、しかも炊飯したときの食味が通常の炊飯米と同程度の食味を有する早炊き米の製造方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明者らは、前記の目的を達成すべく鋭意研究を重ねた結果、本発明を完成するに至った。
すなわち、本発明は
（１）浸漬処理米をセラミックボール層を通過させた加熱蒸気により蒸煮処理し、得られた蒸煮処理米を開放下で空気吸引して急速に冷却する早炊き米の製造方法、
（２）上部に米供給口を底部に開閉自在の排出口を有し傾斜させてある略筒状の蒸煮装置の内腔に浸漬処理米を収容し、前記略筒状の蒸煮装置の内腔の全域にわたる所定箇所から加熱蒸気を噴射して蒸煮処理する（１）の早炊き米の製造方法、
（３）蒸煮処理米を空気透過可能な搬送コンベアー上へ移替するとともに前記搬送コンベアーの下方から空気吸引して急速に冷却する（１）乃至（２）の早炊き米の製造方法、
（４）蒸煮処理米の品温を５〜９０秒で０〜４０℃となるように冷却処理する（１）乃至（３）の早炊き米の製造方法、
を提供するものである。
【０００６】
【発明の実施の形態】
以下本発明を詳細に説明する。なお、本発明において％とは、特に規定している場合を除き、すべて重量％である。
本発明において早炊き米とは、通常の炊飯米やおこわなどを製する際に行われている水洗いや水浸漬が不要で、しかも通常の炊飯や蒸しに要する時間より早い時間で炊く（蒸らしも含む）ことができる加工米をいう。なお、蒸煮処理中に加水するような方法により得られた早炊き米は、本発明による早炊き米には含まれない。
【０００７】
本発明において浸漬処理米とは、うるち米、もち米、およびこれらの混合物を水洗いし、その後、水浸漬および水切り処理を行ったものをいう。このようにして得られた本発明の浸漬処理米の水分含量は、通常２８〜４０％程度であり、例えば、水分含量が１５％程度のうるち米用いた場合は、水中に３０分〜３時間程度浸漬すると２８〜３６％程度の水分含量となり、同程度の水分含量のもち米を用いた場合は、水中に１〜１０時間程度浸漬すると３０〜４０％程度の水分含量となる。
なお、水浸漬の際の水温は特に限定するものではないが、好ましくは５０℃以下、さらに好ましくは４０℃以下の水を用いるとよい。５０℃より高い水温の水で浸漬処理を行うと米粒表面の澱粉が溶出するためか、その後の蒸煮処理により得られた処理米が粘り気を有し、その後のほぐし工程で容易に単粒化することが難しく好ましくない。
【０００８】
本発明は、先ず上述の浸漬処理米をセラミックボール層を通過させた加熱蒸気により蒸煮処理する。さらに詳しくは、上部に米供給口を底部に開閉自在の排出口を有し傾斜させてある略筒状の蒸煮装置の内腔に浸漬処理米を収容し、前記略筒状の蒸煮装置の内腔の全域にわたる所定箇所からセラミックボール層を通過させた加熱蒸気を噴射して蒸煮処理する。蒸煮処理条件としては、通常の処理条件でよく、例えば、蒸気圧０．２５〜１．５kg/cm²で２〜１５分間蒸煮処理を行うとよい。これにより、α化度８０％以上、水分含量３０〜４４％程度の蒸煮処理米が得られる。
【０００９】
本発明においてセラミックボール層とは、セラミック製の略球状のボールが側面より見たとき積層させてある状態をいい、本発明においては、少なくとも２層のセラミックボール層を要する。セラミックボール層が１層であると、水蒸気の微粒子に荒いものを含んでいるためか蒸煮処理米の米粒表面が湿潤で粘り気を有し、その後のほぐし工程で容易に単粒化することが難しく好ましくない。本発明で用いるセラミックボールの大きさは、特に限定するものではないが、直径５〜３０mm程度のものを用いるとよい。
【００１０】
また、加熱蒸気とは、工業的に一般に使用されているボイラーなどで製した１００℃以上の蒸気であり、本発明では、セラミックボール層を通過し蒸煮装置の内腔へ噴射するときの噴射直後の温度が１００〜１１０℃、好ましくは１００〜１０５℃と成るような加熱蒸気を用いる。加熱蒸気の温度が１００℃より低いと蒸煮処理米の米粒表面が湿潤で粘り気を有し、その後のほぐし工程で容易に単粒化することが難しく好ましくない。一方、１１０℃より高いと米粒表面が焼けたような状態となり、商品価値を損なうこととなり好ましくない。
【００１１】
本発明において傾斜させてある略筒状の蒸煮装置の内腔とは、傾斜角が３０〜８０°、好ましくは４５〜７０°程度に配設された角筒、円筒などのような形状を有した蒸煮装置の内腔をいう。傾斜角が３０°より小さいと、内腔の排出口から蒸煮処理米が自重により排出されず、そのため別途強制排出装置を設ける必要があり、これにより米粒同士が結着して塊状となり好ましくない。一方、８０°より大きいと蒸煮処理米の自重により米粒同士が結着し塊状となり易く好ましくない。略筒状の内腔の長さは、蒸煮処理時間および処理量により適宜選択すればよく、また、略筒状の内腔の太さは、米粒と加熱蒸煮を噴射する噴射孔との最短距離が３０cm以内となるようにするとよい。３０cmより遠いと加熱蒸気が十分当たらない部分ができ、蒸煮むらを生ずる場合があり好ましくない。
【００１２】
また、略筒状の内腔の全域にわたる所定箇所から加熱蒸気を噴射するとは、内腔の全域にわたり加熱蒸気が均一に噴射できるように噴射孔を設けておき、蒸気噴射することをいい、例えば、内腔の全壁面に、あるいは後述の実施例に示すようにある特定壁面に加熱蒸煮の噴射孔を設けるとよい。これにより、蒸煮むらの無い均一な蒸煮処理米が得られる。
【００１３】
本発明は、次に上述で得られた蒸煮処理米を開放下で空気吸引して急速に冷却する。本発明において蒸煮処理米を開放下で空気吸引して冷却するとは、真空冷却のように閉鎖した状態で行うのでなく、空気が自由に出入りできるような状態で、蒸煮処理米の粒毎の周辺にある空気を吸引する吸引方式によりその空気の流れによって蒸煮処理米を冷却することをいい、好ましくは、蒸煮処理米を、例えば、ネットコンベアーなどのような空気透過可能な搬送コンベアー上へ移替するとともに前記搬送コンベアーの下方から空気吸引して冷却する。なお、搬送コンベアーの上方より空気吸引すると、冷却過程で蒸煮処理米から蒸発した水分が水滴として処理米に落下し、その部分の米粒同士が結着し強固な塊状となり易く好ましくない。
【００１４】
本発明において蒸煮処理米を急速に冷却するとは、蒸煮処理米を約９０秒以内でその品温が０〜４０℃となるように冷却することをいい、詳しくは５〜９０秒でその品温が０〜４０℃となるように、好ましくは５〜６０秒でその品温が０〜３０℃となるように冷却するとよい。このように空気吸引により急速に冷却するには、少なくとも２０m³／分の風量で吸引する必要があり、この冷却により、米粒中の一部の水分が蒸発するため、米粒の水分含量は２８〜４０％程度となる。冷却時間が９０秒より長い、あるいは品温が４０℃より高いと米粒同士が結着し強固な塊状となり、一方、品温が０℃以下となると米粒が凍結し好ましくない。なお、冷却時間を５秒以上としたのは、工業規模での生産が難しいためである。
【００１５】
本発明は得られる早炊き米の品位を損なわない範囲で、前記搬送コンベアーの前に同様な、あるいは別の搬送コンベアーを設けてもよく。また、上述の方法で品温が０〜４０℃となるように冷却した後も、さらに前記品温の範囲で空気吸引、あるいは別の方法で冷却してもよい。
【００１６】
以上の方法により得られた処理米を次にほぐして単粒化し本発明の早炊き米を得る。なお、本発明により得られた早炊き米は、必要に応じポリエチレン製やナイロン製などの袋などに充填・密封してもよく、また。単粒化前、あるいは単粒化後の処理米をさらに常法により乾燥し、例えば、水分含量２０％以下の早炊き米としてもよい。
【００１７】
【作用】
本発明により得られた早炊き米は如何なる理由により、（１）従来行っていた約１日間の熟成工程を行うことなく、かつ商品価値を損なうことなくほぐして容易に単粒化することができるか、また、（２）炊飯したときの食味が通常の炊飯米と同程度の食味を有するのかは定かでないが、前記（１）については、ボイラーなどで製した加熱蒸気中には、飽和蒸気や過熱蒸気以外にボイラーから送気される際に配管の放熱により生じるドレン（凝縮水）の小滴が多数存在していると言われており、ボイラーなどで製した加熱蒸気を直接用いると、前記ドレンの小滴により米粒表面が濡れた状態となり、米粒がα化される過程で米粒中の澱粉が米粒表面の濡れた部分に析出し、米粒表面が粘り気を有するのに対し、本発明は、ボイラーなどで製した加熱蒸気をセラミックボール層を通過させることにより、前記ドレンの小滴が加熱蒸気中より除去され、そのため米粒表面が濡れた状態となり難くほぐし易い蒸煮処理米が得られるためではないかと推察される。また、後述する図３および図４の冷却方式の説明図に示しているとおり、従来の空気吹きつけ方式では、米粒間の空気の流れが妨げられ、冷却過程で冷却むらを生じ米粒同士が結着し易い状態となるのに対し、本発明の空気吸引方式で行うことにより、米粒間にも空気の流れができ、むらなく冷却できることから、ほぐし易い状態となり、さらに、開放下で行うことにより、米粒同士が締まることなく冷却されるためではないかと推察される。
【００１８】
前記（２）については、従来の真空冷却では、急激に真空に近い状態となるように吸引するためか、米粒中の旨味成分をも吸引されるのに対し、本発明は、開放下で行っていることより、このようなことが起こらないためではないかと推察される。
【００１９】
以下、本発明を本発明の一実施例の図面を参照しながらその実施例および試験例でもって更に詳しく説明する。図１は本発明を実施した早炊き米製造装置の説明用正面図、図２は冷却装置の空気吸引部分の概略説明図、図３は本発明の空気吸引方式による冷却方式の説明図、図４は従来の空気吹きつけ方式による冷却方式の説明図である。
【００２０】
【実施例】
実施例１
精米したうるち米を洗浄した後、２５℃程度の水温の清水に１．５時間浸漬し、次に水切りして水分含量約３２％の浸漬処理米を得た。
【００２１】
次に、前記浸漬処理米を蒸煮装置１で蒸煮処理した。つまり、前記浸漬処理米を蒸煮装置１の米供給口２より長さ１３０cm×幅６０cm×厚さ２０cmとしてあり傾斜角６０°の角筒状の内腔３へ連続的に供給した。一方、スパージパイプ４、４より噴射し９〜１０層から成るセラミックボール（直径約２０mm）層５を通過させた加熱蒸気（ａ、ａ、・・）を蒸気室６より内腔３へ噴射孔（７、７、・・）を介して蒸気圧約０．８kg/cm²で噴射し、前記内腔３へ供給した浸漬処理米を８分間蒸煮処理し、切り出し装置８で蒸煮処理米を排出口９より切り出した。なお、スタート時の蒸煮処理は、排出口９に位置するダンパー１０を閉鎖状態で８分間蒸煮処理し、その後はダンパー１０を開放状態のまま蒸煮処理時間が８分間となるように切り出し装置８で蒸煮処理米を切り出しながら１t/hr程度の速度で連続的に蒸煮処理した。また、得られた蒸煮処理米の水分含量は約３６％であり、α化度は約９５％であった。
【００２２】
次に、前記蒸煮処理米を冷却装置１１で冷却した。つまり、前記蒸煮処理米を空気透過可能な搬送コンベアーであるネットコンベアー１２に移替するとともに、ネットコンベアー１２の下部に位置する吸気ダクト１３、１３、１３より風量１２０m³／分程度で吸引する。これによりエアー濾過フィルター１４で濾過された空気を吸引し、この吸引空気によりネットコンベアー１２上の蒸煮処理米を約３０秒で２５℃程度まで冷却し、水分含量を約３２％とする。搬送後のネットコンベアー１２はネット洗浄槽１５で洗浄され、水切りスリット１６で水切りされる。また、吸引空気（ｂ、ｂ、・・）は、図２に示すように、別途水槽１７に溜めた清水１８をポンプ１９で噴射ノズル２０へ移送し、噴射ノズル２０より清水１８を噴射することで噴射室２５の雰囲気を陰圧状態とし得る構造としてある。また、この噴射室２５は前記吸気ダクト１３、１３、１３に連通してあるので、これにより外空気はエアー濾過フィルター１４、ネットコンベアー１２および吸気ダクト１３を経由して吸引空気（ｂ、ｂ、・・）とされる。
【００２３】
次に、前記冷却処理された米をほぐし機２１で単粒化するために、ほぐし用ネットコンベアー２２とその下方に配設された約５mm目のステンレス製の網板２３の間隙に前記冷却処理米を移替するとともに挟持する。ほぐし用ネットコンベアー２２の回転により前記間隙で冷却処理米をすりほぐし、網板２３の網目を通過させることで単粒化した本発明の早炊き米を得る。なお、本実施例では、ほぐし用ネットコンベアー２２と網板２３の最小間隙を約５mmとして上述のほぐしを行った。
【００２４】
得られた早炊き米（原料米：うるち米）５００ｇに同量の清水を加え炊飯器により炊飯米を製した（炊飯時間：約２０分）。一方、上述の途中工程で得られた浸漬処理米５００ｇを用い同様な方法で炊飯米を製した（炊飯時間：約３０分）。その結果、浸漬処理に要する時間を１．５時間とすると、早炊き米を用いたほうが、精米したうるち米から炊飯米を製するより、浸漬処理時間と炊飯時間の約１．７時間程を短縮でき、また、得られた炊飯米は、同様な食味を有していた。
【００２５】
実施例２
精米したもち米を洗浄した後、２５℃程度の水温の清水に４時間浸漬し、次に水切りして水分含量約３６％の浸漬処理米を得た。この浸漬処理米を実施例１と同様な方法で本発明の早炊き米を製造した。なお、蒸煮処理米の水分含量は約４０％、α化度は約９５％であり、また、冷却処理米の水分含量は約３６％であった。
【００２６】
得られた早炊き米（原料米：もち米）６００ｇを５分間せいろ蒸しを行い、清水２００ｇを打ち水し均一とした後、さらに１０分間せいろ蒸しを行いせいろ米を製した（せいろ蒸し時間：約１５分）。一方、上述の途中工程で得られた浸漬処理米６００ｇを２０分間せいろ蒸しを行い、清水２００ｇを打ち水し均一とした後、さらに２０分間せいろ蒸しを行いせいろ米を製した（せいろ蒸し時間：約４０分）。その結果、浸漬処理に要する時間を４時間とすると、早炊き米を用いたほうが、精米したもち米からせいろ米を製するより、浸漬処理時間とせいろ蒸し時間の約４．４時間を短縮でき、また、得られたせいろ米は、同様な食味を有していた。
【００２７】
【試験例】
実施例１において、実施例１のようにセラミックボール層を通過さた加熱蒸気で蒸煮処理を行った場合とそうでない場合、あるいは吸引の風量を種々変えて表１に示す冷却時間とした場合のほぐし機でのほぐし易さ、および得られた早炊き米中の破米の発生状況を目視で観察した。
【００２８】
【表１】

【００２９】
表１より、セラミックボール層を通過させない加熱蒸気で蒸煮処理を行ったもの、あるいは冷却時間が９０秒越えたものは、ほぐし難く、また多くの破米が観察された。
これより、比較的ほぐし易く、破米が少ない早炊き米を得るには、セラミックボール層を通過させた加熱蒸気により蒸煮処理し、得られた蒸煮処理米を開放下で空気吸引して急速に、つまり９０秒以内に冷却する必要があることが理解される。特に、本発明品の内、冷却時間が６０秒以内のものは、ほぐし易く、破米も観察されなかった。
【００３０】
【発明の効果】
以上述べたように、本発明によれば、従来行っていた約１日間の熟成工程を行わなくても商品価値を損なうことなくほぐすことが可能であるため、早炊き米を効率良く製造でき、しかも炊飯したときの食味が通常の炊飯米と同程度の食味を有する早炊き米を提供することができることから、早炊き米の更なる生産性および需要の拡大が期待される。
【００３１】
【図面の簡単な説明】
【図１】早炊き米製造装置の説明用正面図
【図２】冷却装置の空気吸引部分の概略説明図
【図３】本発明の空気吸引方式による冷却方式の説明図
【図４】従来の空気吹きつけ方式による冷却方式の説明図
【符号の説明】
１蒸煮装置
２米供給口
３内腔
４スパージパイプ
５セラミックボール層
６蒸気室
７噴射孔
８切り出し装置
９排出口
１０ダンパー
１１冷却装置
１２ネットコンベアー
１３吸気ダクト
１４エアー濾過フィルター
１５ネット洗浄槽
１６水切りスリット
１７水槽
１８清水
１９ポンプ
２０噴射ノズル
２１ほぐし機
２２ほぐし用ネットコンベアー
２３網板
２４米粒
２５噴射室
ａ加熱蒸気
ｂ吸引空気
ｃ吹きつけ空気[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing quick-cooked rice.
[0002]
[Prior art]
Pre-treatment such as washing with water or water soaking when making regular cooked rice or rice bran is unnecessary, and it can be cooked (including steamed) in an earlier time than normal cooking and steaming. Quick-cooked rice is known as processed rice, and in recent years, the demand has increased because it can be easily cooked in this way.
As a conventional method for producing quick-cooked rice, for example, as described in JP-A-1-304856, after immersion-treated rice is steamed with live steam, it is rapidly cooled to about 25 ° C. by vacuum cooling, and then 1 to Aged for 2 days, loosened into single grains, then packed into bags, and as described in JP-A-7-31540, the soaked rice was steamed with raw steam using a steaming device equipped with a quantitative feeder, and obtained. A method is known in which a certain amount of the cooked rice is put into a bag, rapidly cooled and sealed with a vacuum cooling packaging device, then aged for 1 to 2 days, and then loosened to become a single grain.
[0003]
However, each of the above-described conventional production methods has a problem in production efficiency because it requires a maturing step of 1 to 2 days.
Although it is possible to loosen without performing the ripening step, the state of the cooked rice before the ripening step is steamed with raw steam or the rice grain surface is wet and sticky, and the rice grains are easy to bind. It was in a state. Moreover, the sticky rice grains were more firmly bound and formed into a lump by forced discharge by a quantitative feeder and subsequent instantaneous cooling by vacuum cooling. Therefore, it is difficult to loosen the rice before the ripening process and make it easy to make a single grain, and even if it is loosened, the quick-cooked rice that has been obtained contains a lot of broken rice derived from the loosening process and tends to impair the product value It was in.
Furthermore, in the conventional method described above, the quick-cooked rice obtained because the cooling is performed in a vacuum state is unlikely to have a taste similar to that of ordinary cooked rice when cooked. It was a thing.
[0004]
[Problems to be solved by the invention]
Therefore, the purpose of the present invention is to produce quick-cooked rice that can be efficiently cooked without losing commercial value, and the taste when cooked is comparable to that of ordinary cooked rice It aims to provide a method.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have completed the present invention.
That is, the present invention is (1) a method for producing fast-cooked rice, in which immersion-treated rice is steamed with heated steam that has passed through a ceramic ball layer, and the steamed rice thus obtained is rapidly cooled by air suction under open conditions. ,
(2) The soaked rice is accommodated in the lumen of a substantially cylindrical steaming device that has a rice supply port at the top and a discharge port that can be opened and closed at the bottom and is inclined, and the lumen of the substantially cylindrical steaming device (1) The method for producing quick-cooked rice, which is steamed by spraying heated steam from a predetermined location over the entire area of
(3) The method for producing quick-cooked rice according to (1) to (2), wherein the steamed rice is transferred onto a conveyer capable of transmitting air and rapidly cooled by sucking air from below the conveyer,
(4) The method for producing quick-cooked rice according to (1) to (3), wherein the temperature of the cooked rice is 0 to 40 ° C. in 5 to 90 seconds,
Is to provide.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. In the present invention, “%” means “% by weight” unless otherwise specified.
In the present invention, quick-cooked rice is not required to be washed or soaked when making regular cooked rice or rice bran, and is cooked in a time earlier than the time required for regular cooked rice or steaming (steamed) Processed rice that can be included). In addition, the quick-cooked rice obtained by the method of adding water during the steaming process is not included in the quick-cooked rice according to the present invention.
[0007]
In the present invention, the soaked rice refers to a product obtained by washing water with glutinous rice, glutinous rice, and a mixture thereof, followed by water soaking and draining. The water content of the soaked rice of the present invention thus obtained is usually about 28 to 40%. For example, in the case of using glutinous rice having a water content of about 15%, it is about 30 minutes to 3 hours in water. When immersed, the moisture content is about 28 to 36%. When glutinous rice having the same moisture content is used, the moisture content is about 30 to 40% when immersed in water for about 1 to 10 hours.
In addition, although the water temperature in the case of water immersion is not specifically limited, Preferably it is 50 degrees C or less, It is good to use the water of 40 degrees C or less. If the immersion treatment is performed with water having a water temperature higher than 50 ° C, the starch on the surface of the rice grains will be eluted, or the treated rice obtained by the subsequent steaming treatment will be sticky and easily become single grains in the subsequent loosening process It is difficult and undesirable.
[0008]
In the present invention, first, the above-described soaked rice is steamed with heated steam that has passed through a ceramic ball layer. More specifically, the soaked rice is accommodated in the lumen of a substantially cylindrical steaming device that has a rice supply port at the top and a discharge port that can be opened and closed at the bottom, and the inside of the substantially cylindrical steaming device. Steaming is performed by spraying heated steam that has passed through the ceramic ball layer from a predetermined location over the entire cavity. The steaming treatment conditions may be normal processing conditions. For example, the steaming treatment may be performed at a steam pressure of 0.25 to 1.5 kg / cm ² for ² to 15 minutes. As a result, steamed rice having a degree of gelatinization of 80% or more and a water content of about 30 to 44% is obtained.
[0009]
In the present invention, the ceramic ball layer refers to a state in which ceramic substantially spherical balls are laminated when viewed from the side, and in the present invention, at least two ceramic ball layers are required. If the ceramic ball layer is a single layer, the surface of the grain of steamed rice is moist and sticky because it contains coarse particles of water vapor, and it is difficult to easily make it into a single grain in the subsequent loosening process. It is not preferable. The size of the ceramic balls used in the present invention is not particularly limited, but those having a diameter of about 5 to 30 mm may be used.
[0010]
Further, the heating steam is steam of 100 ° C. or higher made by a boiler that is generally used in industry, and in the present invention, immediately after injection when passing through the ceramic ball layer and spraying into the lumen of the steaming device. The heating steam is used so that the temperature of the water becomes 100 to 110 ° C, preferably 100 to 105 ° C. When the temperature of the heating steam is lower than 100 ° C., the surface of the rice grain of the steamed rice is wet and sticky, and it is not preferable because it is difficult to easily make a single grain in the subsequent loosening step. On the other hand, when the temperature is higher than 110 ° C., the surface of the rice grain is in a burned state, which impairs the commercial value.
[0011]
The lumen of the substantially cylindrical steaming device inclined in the present invention has a shape such as a rectangular tube, a cylinder, etc. with an inclination angle of 30 to 80 °, preferably about 45 to 70 °. Refers to the lumen of the cooking apparatus. When the inclination angle is less than 30 °, the steamed rice is not discharged from the discharge port of the lumen due to its own weight, and therefore, it is necessary to provide a separate forced discharge device. On the other hand, if it is larger than 80 °, the rice grains are bound to each other due to the weight of the steamed rice, and it is not preferable. The length of the substantially cylindrical lumen may be appropriately selected depending on the cooking process time and amount, and the thickness of the substantially cylindrical lumen is the shortest distance between the rice grain and the injection hole for injecting the heating steam. Should be within 30cm. If the distance is more than 30 cm, a portion where the heated steam does not sufficiently hit is formed, which may cause uneven cooking, which is not preferable.
[0012]
Further, to inject the heating steam from a predetermined location over the entire area of the substantially cylindrical lumen means that the injection holes are provided so that the heating steam can be uniformly injected over the entire area of the lumen, and the steam is injected, for example In addition, it is preferable to provide spray holes for heating and steaming on the entire wall surface of the lumen or on a specific wall surface as shown in the examples described later. Thereby, the uniform steamed rice without steaming unevenness is obtained.
[0013]
In the present invention, the steamed rice obtained as described above is rapidly cooled by air suction while being opened. In the present invention, the steaming of the steamed rice under open air cooling is not performed in a closed state like vacuum cooling, but in a state where air can freely enter and exit, the periphery of each steamed rice is peripheries. It is said that the steamed rice is cooled by the flow of air by a suction method for sucking air, and preferably, the steamed rice is transferred to an air permeable transport conveyor such as a net conveyor. At the same time, air is sucked from below the conveyor to cool it. In addition, when air is sucked from above the conveyor, moisture evaporated from the steamed rice during the cooling process falls to the treated rice as water droplets, and the rice grains in the portion are easily bonded together to form a solid lump, which is not preferable.
[0014]
In the present invention, rapidly cooling the steamed rice means cooling the steamed rice so that the product temperature becomes 0 to 40 ° C. within about 90 seconds, and more specifically, the product temperature in 5 to 90 seconds. Is preferably cooled so that the product temperature becomes 0 to 30 ° C. in 5 to 60 seconds. In order to rapidly cool by air suction in this way, it is necessary to suck at an air volume of at least 20 m ³ / min, and this cooling evaporates some of the moisture in the rice grain, so that the moisture content of the rice grain is 28 to It becomes about 40%. When the cooling time is longer than 90 seconds or the product temperature is higher than 40 ° C., the rice grains are bonded to each other to form a strong lump. On the other hand, when the product temperature is 0 ° C. or less, the rice grains are frozen, which is not preferable. The reason why the cooling time is set to 5 seconds or more is that production on an industrial scale is difficult.
[0015]
In the present invention, a similar or another transport conveyor may be provided in front of the transport conveyor as long as the quality of the quick-cooked rice obtained is not impaired. Further, even after the product temperature is cooled to 0 to 40 ° C. by the above-described method, it may be further cooled by air suction or another method within the range of the product temperature.
[0016]
Next, the treated rice obtained by the above method is loosened into single grains to obtain the quick-cooked rice of the present invention. The quick-cooked rice obtained by the present invention may be filled and sealed in bags made of polyethylene or nylon as necessary. The treated rice before or after single graining may be further dried by a conventional method, for example, as quick-cooked rice having a water content of 20% or less.
[0017]
[Action]
For any reason, the quick-cooked rice obtained by the present invention can be easily broken into single grains without (1) performing the conventional aging process for about 1 day and without damaging the commercial value. Or (2) It is not certain whether the taste when cooked rice is comparable to that of ordinary cooked rice, but with regard to (1) above, saturated steam is used in heated steam produced by a boiler or the like. It is said that there are many small droplets of drain (condensate) generated by heat dissipation of the pipe when it is sent from the boiler other than the superheated steam, and when directly using heated steam made by a boiler, The rice grain surface becomes wet due to the small droplets of drain, and the starch in the rice grain is deposited in the wet part of the rice grain surface in the process of pregelatinizing the rice grain, while the rice grain surface is sticky. , Made with boiler By the heating steam to pass through the ceramic balls layer, droplets of the drain are removed from a heated steam, therefore rice grain surface wet and not easily loosened easily steaming rice is inferred whether not to be obtained. In addition, as shown in the explanatory views of the cooling method in FIGS. 3 and 4 to be described later, in the conventional air blowing method, the flow of air between the rice grains is hindered, resulting in uneven cooling during the cooling process, and the rice grains are bound to each other. While it is easy to wear, by using the air suction method of the present invention, air can flow between the rice grains, and it can be cooled evenly. It is guessed that the rice grains are cooled without tightening.
[0018]
With regard to (2), the conventional vacuum cooling is performed so that the umami component in the rice grain is also sucked in order to suck the vacuum so that it is almost in a vacuum state. It is speculated that this may not happen.
[0019]
Hereinafter, the present invention will be described in more detail with reference to the drawings of one embodiment of the present invention and its embodiments and test examples. FIG. 1 is an explanatory front view of a quick-cooked rice production apparatus embodying the present invention, FIG. 2 is a schematic explanatory view of an air suction portion of a cooling device, and FIG. 3 is an explanatory view of a cooling method by an air suction method of the present invention. 4 is an explanatory view of a cooling method by a conventional air blowing method.
[0020]
【Example】
Example 1
After washing polished rice, it was immersed in fresh water having a water temperature of about 25 ° C. for 1.5 hours, and then drained to obtain immersion-treated rice having a water content of about 32%.
[0021]
Next, the immersion-treated rice was steamed with the steaming apparatus 1. That is, the immersion-treated rice was continuously supplied from the rice supply port 2 of the steaming device 1 to a rectangular tube-shaped lumen 3 having a length of 130 cm, a width of 60 cm, and a thickness of 20 cm and an inclination angle of 60 °. On the other hand, the heated steam (a, a,...) Sprayed from the sparge pipes 4 and 4 and passed through the ceramic ball (diameter about 20 mm) layer 5 composed of 9 to 10 layers is ejected from the steam chamber 6 to the lumen 3 ( 7,7, ...) via the injected steam pressure of about 0.8 kg / cm ^2, the immersion treatment rice supplied to the lumen 3 to 8 minutes steaming, the steaming rice with clipping device 8 outlet 9 Cut out more. In addition, the steaming process at the start is performed by the cutting device 8 such that the damper 10 located at the discharge port 9 is steamed for 8 minutes with the damper 10 closed, and then the steaming time is 8 minutes with the damper 10 open. Steaming was performed continuously at a rate of about 1 t / hr while cutting the steamed rice. Moreover, the moisture content of the obtained steamed rice was about 36%, and the pregelatinization degree was about 95%.
[0022]
Next, the steamed rice was cooled with a cooling device 11. That is, the steamed rice is transferred to a net conveyor 12 that is a transport conveyor that allows air to pass through and is sucked from the intake ducts 13, 13, and 13 located below the net conveyor 12 at an air volume of about 120 m ³ / min. Thereby, the air filtered by the air filter 14 is sucked, and the steamed rice on the net conveyor 12 is cooled to about 25 ° C. in about 30 seconds by this sucked air, so that the water content is about 32%. The transported net conveyor 12 is cleaned in a net cleaning tank 15 and drained by a draining slit 16. Further, as shown in FIG. 2, the suction air (b, b,...) Is obtained by transferring fresh water 18 separately stored in the water tank 17 to the injection nozzle 20 by the pump 19 and injecting the fresh water 18 from the injection nozzle 20. Thus, the atmosphere of the injection chamber 25 can be set to a negative pressure state. Further, since the injection chamber 25 communicates with the intake ducts 13, 13, 13, external air is thereby sucked through the air filtration filter 14, the net conveyor 12 and the intake duct 13 (b, b,・・）.
[0023]
Next, in order to make the cooled rice into a single grain by the loosening machine 21, the cooling treatment is carried out in the gap between the loosening net conveyor 22 and a stainless steel net plate 23 of about 5 mm disposed below. Transfer and hold rice. By cooling the net conveyor 22 for loosening, the cooling-treated rice is loosened in the gaps and passed through the mesh of the mesh plate 23 to obtain the quick-cooked rice of the present invention. In the present example, the above-described unraveling was performed with the minimum gap between the unraveling net conveyor 22 and the net plate 23 being about 5 mm.
[0024]
The same amount of fresh water was added to 500 g of the obtained quick-cooked rice (raw rice: glutinous rice), and cooked rice was made with a rice cooker (rice cooking time: about 20 minutes). On the other hand, cooked rice was made in the same manner using 500 g of the immersion-treated rice obtained in the above-mentioned intermediate process (rice cooking time: about 30 minutes). As a result, assuming that the time required for the immersion treatment is 1.5 hours, using rice cooked quickly shortens the immersion treatment time and rice cooking time by about 1.7 hours compared to producing cooked rice from polished rice. The cooked rice thus obtained had a similar taste.
[0025]
Example 2
After the polished glutinous rice was washed, it was immersed in fresh water having a water temperature of about 25 ° C. for 4 hours, and then drained to obtain immersion-treated rice having a water content of about 36%. By using this soaked rice in the same manner as in Example 1, quick-cooked rice of the present invention was produced. The water content of the steamed rice was about 40%, the degree of pregelatinization was about 95%, and the water content of the cooled rice was about 36%.
[0026]
600 g of the obtained quick-cooked rice (raw rice: glutinous rice) was subjected to steaming for 5 minutes, 200 g of fresh water was sprinkled and homogenized, and then steamed for 10 minutes to produce steamed rice (steamed steaming time: approximately 15 minutes). On the other hand, 600 g of the soaked rice obtained in the above-mentioned intermediate process was steamed for 20 minutes, 200 g of fresh water was sprinkled and made uniform, and then steamed for 20 minutes to make steamed rice (steamed steaming time: about 40 minutes). As a result, assuming that the time required for the soaking process is 4 hours, using quick-cooked rice can shorten the soaking time and steaming time by approximately 4.4 hours, rather than making seiiro rice from polished glutinous rice. Moreover, the obtained rice bran had the same taste.
[0027]
[Test example]
In Example 1, when the steaming treatment was performed with the heated steam that passed through the ceramic ball layer as in Example 1 or not, or when the cooling time shown in Table 1 was changed by variously changing the suction air volume The ease of unraveling with the unraveling machine and the occurrence of broken rice in the obtained quick-cooked rice were visually observed.
[0028]
[Table 1]

[0029]
From Table 1, it was difficult to loosen those that had been steamed with heated steam that did not pass through the ceramic ball layer, or those that had a cooling time of more than 90 seconds, and many broken rice were observed.
From this, in order to obtain quick-cooked rice that is relatively easy to loosen and less broken rice, steaming is performed with heated steam that has passed through the ceramic ball layer, and the steamed rice thus obtained is rapidly sucked into the air under open conditions. That is, it is understood that cooling is required within 90 seconds. In particular, among the products of the present invention, those having a cooling time of 60 seconds or less were easy to loosen and no broken rice was observed.
[0030]
【The invention's effect】
As described above, according to the present invention, it is possible to unravel the product value without losing the commercial value without performing the aging process of about 1 day that has been conventionally performed, and thus, it is possible to efficiently produce rice that has been cooked quickly, Moreover, since it is possible to provide quick-cooked rice having a taste similar to that of ordinary cooked rice when cooked, it is expected to further increase the productivity and demand of the cooked rice.
[0031]
[Brief description of the drawings]
FIG. 1 is an explanatory front view of a quick-cooking rice production apparatus. FIG. 2 is a schematic explanatory view of an air suction portion of a cooling apparatus. FIG. 3 is an explanatory view of a cooling system using an air suction system of the present invention. Explanatory diagram of cooling method by air blowing method [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steaming device 2 Rice supply port 3 Lumen 4 Sparge pipe 5 Ceramic ball layer 6 Steam chamber 7 Injection hole 8 Cutting device 9 Outlet 10 Damper 11 Cooling device 12 Net conveyor 13 Intake duct 14 Air filtration filter 15 Net washing tank 16 Draining slit 17 water tank 18 fresh water 19 pump 20 spray nozzle 21 unwinding machine 22 unwinding net conveyor 23 mesh plate 24 rice grain 25 spray chamber a heating steam b suction air c blowing air

Claims

A method for producing fast-cooked rice, wherein the soaked rice is steamed with heated steam that has passed through a ceramic ball layer, and the steamed rice thus obtained is rapidly cooled by air suction under open conditions.

The rice supply port is placed at the top, the bottom is provided with a discharge port that can be freely opened and closed, and the soaked rice is accommodated in the inner cavity of the substantially cylindrical steaming device that is inclined, and covers the entire lumen of the substantially cylindrical steaming device. The method for producing quick-cooked rice according to claim 1, wherein steaming is performed by spraying heated steam from a predetermined location.

The method for producing fast-cooked rice according to claim 1 or 2, wherein the steamed rice is transferred onto a conveyer that is permeable to air and rapidly cooled by sucking air from below the conveyer.

The manufacturing method of the quick-cooked rice of Claims 1 thru | or 3 which cool-process so that the product temperature of steaming process rice may be 0-40 degreeC in 5-90 second.