JP3898270B2

JP3898270B2 - Cereal freshness preservation method

Info

Publication number: JP3898270B2
Application number: JP07712197A
Authority: JP
Inventors: 清尾崎; 良夫佐藤; 泰道佐藤
Original assignee: Nippon Soda Co Ltd
Current assignee: Nippon Soda Co Ltd
Priority date: 1997-03-28
Filing date: 1997-03-28
Publication date: 2007-03-28
Anticipated expiration: 2017-03-28
Also published as: JPH10273177A

Description

【０００１】
【発明の属する技術分野】
本発明は、精米直後の米等の穀類を脱酸素剤と共に用いる、包装された穀類の鮮度保持方法に関する。
【０００２】
【従来の技術】
従来、ガスバリアー性の穀類等の保存袋内の一隅に脱酸素剤を封入してなる保存袋（実開昭５９−１４３９７１号、実開昭６０−５０１７１号）や、穀類等の保存袋をガスバリアー性の外袋と酸素透過性の内袋から構成し、外袋と内袋との間に脱酸素剤を入れ、脱酸素剤を保存袋に残したまま穀類等の収納物を保存袋から取り出し得るようにした保存袋（特開昭６３−６７２７５号公報）や、穀類等の保存袋をガスバリアー性の内袋と比較的丈夫で日光遮断性のクラフト紙等からなる外袋から構成し、内袋の中に脱酸素剤と酸素検知剤を収納して、外袋に設けられた窓部から酸素検知剤を目視により確認できるようにした保存袋（特開昭６１−２０３３７８号公報）が知られている。
【０００３】
また、ポテトチップスや米、麦等の食品を、その内部を脱気すると共に、酸素を吸収しかつ炭酸ガス発生機能を有する薬剤を充填した、プラスチックフィルム製の密封袋体に収納し、発生する炭酸ガスにより密封袋体の外的変形を抑制することが知られている（特開平４−２０１８７８号公報）。
【０００４】
そしてまた、ポリエチレンに鱗片状の無機物添加剤を加え、ポリエチレンの分子間の隙間に鱗片状の無機物添加剤が入り込み、その隙間が狭くなった材料で成形された袋体に穀物を入れ、それを真空包装機にかけるか、又は袋体に脱酸素剤を入れて、包装することにより、包装した後に形崩れしない程度の真空度が保持される包装方法が知られている（特開平３−１６２２６８号公報）。
【０００５】
さらに、穀類を、脱酸素剤組成物をガーレー式透気度（ＪＩＳＰ８１１７）２００〜１０００００秒／空気１００ｍｌの通気性包材に密封してなる脱酸素剤とともに実質的に非通気性の包材または気密容器に密封し、酸素濃度０．１％以下で５〜２０℃に保持し、穀類に付着した害虫卵を死滅させ開封後のふ化を防止する穀類の害虫防除方法が知られている（特公昭６４−７７３９号公報）。
【０００６】
他方、近年の米の流通経路の変化に伴い、米は５ｋｇ、１０ｋｇ等の単位で、予め通気性をもたせるために小孔が多数穿設された樹脂製材料で軟包装（フレキシブルパック）した状態で市販されることが多くなってきているが、これらの軟包装米は、小孔が多数穿設されているため脱酸素剤は用いられていなかった。
【０００７】
【発明が解決すべき課題】
最近、本当においしい米を食べたいという消費者嗜好の高まりから、特定品種かつ特定産地、場合によっては特定生産者の良質米の精米直後の米を、５ｋｇ、１０ｋｇ等の単位で軟包装し、産地や生産者から消費者のもとへ直送・宅配する販売方法も増えてきつつある。しかし、かかる包装米を開封・炊飯するまでの間に、良質米の品質が少なからず劣化し、香味等において通常の店頭販売のものと変わらなくなり、産地直送のメリットが生かされないという問題があった。
【０００８】
本発明者らは、これら精米直後の良質米の鮮度保持の観点から、脱酸素剤の適用について検討したところ、開封後及び炊飯時における精米時の良質米の香りが消失したり、精米直後の米粒の食味に比較して不味くなったり、包材からの異臭が包装精米に付加されたりして、通常の脱酸素剤による穀類の酸化防止、殺虫・殺菌等を目的とする場合に比べて、精米等の品質に関する解決しなければならない諸問題があることがわかった。加えて、精米等を包装した枕状の軟包装袋の貯留・搬送、例えばパレットに１０〜１５段積み上げての貯留・搬送に際して、積み上げた米包装袋が崩れて転倒したり、積み上げられた米包装袋の一番下のものが破袋するという実用上大きな問題があることがわかった。
【０００９】
本発明の課題は、上記精米等の品質に関する問題や貯留・搬送に際しての実用上の問題を同時に全て解決する、脱酸素剤を用いた包装形態の精米直後の米等の穀類の優れた鮮度保持方法を提供することにある。
【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、軟包装袋の包材の種類・性能、脱酸素剤の使用条件、精米等の充填時における軟包装袋の包装方法等について鋭意研究したところ、特定の包材、脱酸素剤の特定の使用条件、充填時における軟包装袋の特定の包装方法等、特定の組み合わせを採用した場合、初めて精米直後の米等の穀類の優れた鮮度保持が可能となることを見出し、本発明を完成するに至った。
【００１２】
すなわち、本発明は、穀類を、脱酸素剤と共に、酸素透過度３０ｃｃ／ｍ² ／２４ｈｒ以下で、透湿度１０ｇ／ｍ² ／２４ｈｒ以下の厚み４０μｍ以上の複層バリアフィルムからなる軟包装袋に、減圧下に包装し、開封部を密封した後、軟包装袋に小孔をあけ、該軟包装袋内の気圧を大気圧とした後、再度該小孔を閉塞する工程からなる整形包装を行い、２４〜９６時間で脱酸素状態とすることを特徴とする精米直後の米等の穀類の鮮度保持方法に関する。
【００１３】
同じく、本発明は、穀類を、脱酸素剤と共に、酸素透過度３０ｃｃ／ｍ²／２４ｈｒ以下で、透湿度１０ｇ／ｍ²／２４ｈｒ以下の厚み４０μｍ以上の複層バリアフィルムからなる軟包装袋に、剛性の整形ホルダーを用いて、軟包装袋に米を充填後、可及的に空気を排除してシールする工程からなる整形包装を行い、２４〜９６時間で脱酸素状態とすることを特徴とする精米直後の米等の穀類の鮮度保持方法に関する。
【００１４】
さらに、本発明は、上記穀類の鮮度保持方法において、上記脱酸素剤が、透気度３０００〜１２０００秒の通気性包材に収納された鉄系脱酸素剤を用いる鮮度保持方法や、上記脱酸素剤が、０．０５〜５重量％の活性炭等の吸着剤を含むものを用いる鮮度保持方法や、上記複層バリアフィルムが、厚み４０〜１５０μｍで、少なくともポリプロピレンフィルム層及び／又はアルミ箔層を含み、酸化臭のないものを用いる穀類の鮮度保持方法に関する。
【００１５】
【発明の実施の形態】
本発明において、穀類としては、米、大麦（裸麦を含む）、小麦、ライ麦、えんばく、とうもろこし、ひえ、あわ、もろこし、きびなどの禾穀類の他に大豆を主体とする豆類、及びそばを例示することができる。また、本発明においては、乾茸、茶等の酸化により品質の劣化する固体状の食品素材についても、便宜上穀類と称する。
【００１６】
本発明の鮮度保持方法が、特に適しているのは、精米直後の米、より望ましくは米粒食味値７０以上の良質米であり、本包装により精米時の鮮度が開封後及び炊飯時までそのまま保たれることが確認された。なお、米粒食味値とは、食味分析計により測定され、標準米の食味値を７０とする、米の食味を表す指標である。
【００１７】
本発明において、脱酸素剤とは、空気と接触して酸素を吸収する組成物を通気性小袋や小容器等の包材に収納したものであり、かかる組成物としては、例えば、鉄、炭化鉄などの鉄粉、亜硫酸塩、第一鉄塩などの還元性の無機塩、ヒドロキノン、カテコール、ピロガロール、没食子酸などのポリフェノール類、グルコースなどの還元性糖類、アスコルビン酸、エリソルビン酸などの還元性多価アルコール類等の還元剤を主たる有効成分とするものを例示することができるが、その中でも、鉄粉と電解質、例えば鉄粉とハロゲン化金属を含有する鉄系脱酸素組成物が好ましい。
【００１８】
脱酸素剤は、穀類等の整形包装後の軟包装袋内が２４〜９６時間、望ましくは２４〜４８時間で脱酸素状態となるように、脱酸素剤による発熱を抑制した状態で用いることが必要である。２４時間未満で脱酸素状態にする場合、脱酸素反応により発生する発熱によって、精米等の穀類の品質が低下することになる。また、脱酸素状態になるのに９６時間を超えるような条件で脱酸素剤を用いる場合は、脱酸素状態になるまでの間に精米等の穀類の品質が劣化する恐れがある。
【００１９】
脱酸素剤として、脱酸素組成物の他に、活性炭、ゼオライト等の吸着剤を０．０５〜５重量％含有するものを用いることができる。脱酸素剤として、例えば０．０５〜５重量％の活性炭を含むものを用いると、穀類の好ましくない臭気の他に、複層バリアフィルムに由来する酸化臭をも脱臭することができる。
【００２０】
脱酸素組成物は、透気度３０００〜１２０００秒の通気性包材に収納するのが好ましい。透気度３０００〜１２０００秒の通気性包材に、例えば鉄系脱酸素組成物を収納した脱酸素剤を、精米２〜１０ｋｇを充填後整形包装した軟包装袋に適用すると、軟包装袋内は２４〜９６時間で脱酸素状態になる。
【００２１】
ここで、透気度とは、通気性包材のガーレー式透気度を意味し、透気度３０００〜１２０００秒の通気性包材としては、具体的に、有孔（ポリエチレンテレフタレート／ポリエチレン）／耐水耐油紙／有孔ポリエチレン等からなる樹脂フィルムを例示することができる。
【００２２】
本発明において、軟包装袋の包材である複層バリアフィルムとしては、酸素透過度３０ｃｃ／ｍ²／２４ｈｒ以下、好ましくは２０ｃｃ／ｍ²／２４ｈｒ以下で、透湿度１０ｇ／ｍ²／２４ｈｒ以下、好ましくは５ｇ／ｍ²／２４ｈｒ以下の厚み４０μｍ以上、好ましくは４０〜１５０μｍのものを用いることができる。酸素透過度が３０ｃｃ／ｍ２／２４ｈｒを越えると、軟包装袋の中に酸素が浸透し、脱酸素状態を保持しづらくなり、また、酸素透過度が２０ｃｃ／ｍ²／２４ｈｒ以下のものでは、脱酸素状態を確実に達成することができる。また、透湿度が１０ｇ／ｍ²／２４ｈｒを越えると、軟包装袋の中に水分が湿気として浸入し穀類の鮮度をおとす原因となったり、逆に精米等の水分が逸散し精米等が乾燥して炊飯米の粘りがなくなる等の問題が生じることになるが、透湿度が１０ｇ／ｍ²／２４ｈｒ以下のものでは、その恐れがほとんどない。そして、複層バリアフィルムの厚みが、４０μｍ未満であると包材としての強度不足の恐れがあり、流通過程において軟包装袋が破損したりピンホールが生じる恐れがあり、１５０μｍを越えると、強度の面では十分であるが、硬くて扱いにくい上に材料費がかさむことになる。
【００２３】
本発明における複層バリアフィルムの材質としては、二軸延伸ポリプロピレン（ＯＰ）、ポリ塩化ビニリデンコート二軸延伸ポリプロピレン（ＫＯＰ）、アルミ箔やアルミ蒸着などのアルミ（Ａｌ）、延伸ナイロン（ＯＮ）、ポリ塩化ビニリデンコート延伸ナイロン（ＫＯＮ）、ナイロン（ＮＹ）、未延伸ポリプロピレン（ＣＰＰ）、ポリエチレンテレフタレート（ＰＥＴ）、ポリ塩化ビニリデンコートポリエチレンテレフタレート（ＫＰＥＴ）、ポリエチレン（ＰＥ）、ポリ塩化ビニリデンコートポリエチレン（ＫＰＥ）、直鎖状低密度ポリエチレン（ＬＬＤＰＥ）などを挙げることができ、積層構造として具体的には、ＯＮ／ＰＥ、ＫＰＥＴ／ＰＥ、ＫＯＮ／ＰＥ、ＫＯＰ／ＰＥ、ＫＯＰ／ＮＹ／ＰＥ／ＬＬＤＰＥ、ＰＥＴ／ＰＥ／紙／ＰＥ、ＯＮ／ＰＥ／紙／ＰＥ、ＫＰＥＴ／ＰＥ／紙／ＰＥ、ＫＯＮ／ＰＥ／紙／ＰＥ、ＫＯＰ／ＰＥ／紙／ＰＥ、紙／ＰＥ／ＯＮ／ＰＥ、紙／ＰＥ／ＫＰＥＴ／ＰＥ、紙／ＰＥ／ＫコートＯＮ／ＰＥ、紙／ＰＥ／ＫＯＰ／ＰＥ、紙／ＰＥ／塩化ビニリデン／ＰＥ、ＰＥＴ／ＰＥ／Ａｌ／ＰＥ、ＯＮ／ＰＥ／Ａｌ／ＰＥ、ＯＰ／ＰＥ／Ａｌ／ＰＥ、ＯＰ／ＮＹ／ＰＥ／ＬＬＤＰＥ等の複層バリアフィルムを例示することができるが、ＰＥＴ／ＰＥ／Ａｌ／ＰＥ、ＫＯＰ／ＮＹ／ＰＥ／ＬＬＤＰＥ、ＯＰ／ＮＹ／ＰＥ／ＬＬＤＰＥ等の複層バリアフィルムが望ましい。
【００２４】
本発明における複層バリアフィルムとして要求される特性としては、上記の他に、良好なシール性や酸化臭がないことが挙げられる。収納する穀類が精米直後の良質米のように、香味等において特に新鮮度が要求される場合には、複層バリアフィルムとして酸化臭のないものが用いることが望ましいが、ここでいう酸化臭とは、ラミ臭又はポリ臭とも呼ばれるもので、複層バリアフィルムの製造過程において、ラミネート加工時に溶融したプラスチックの熱劣化により生じるもので、フィルムポリマーの酸化物に起因する異臭をいう。
【００２５】
本発明において、軟包装袋とは、フレキシブルパックとも呼ばれ、あらかじめ形状を固定したコンテナと異なり、複層バリアフィルムからなる包装材料にて形成された袋に穀類を収納した包装袋を意味する。
【００２６】
本発明において、整形包装とは、米粒と米粒との隙間等穀類間の空気は残すが、その他の袋内の余分な空気をできるだけ追い出し、軟包装袋内に穀類がほぼ満たされた状態とする包装をいい、これを例えば１０〜１５段積み上げたときに崩れることがないような包装方法をいう。
この整形包装は、脱酸素剤を適用すると、包装袋内に存在する空気の２０％を占める酸素が吸収されることから、その分を見込んで従来行われている含気包装とは異なる。含気包装では、包装直後、例えば１０〜１５段積み上げようとしても不安定となり、崩れたり転倒することがあるばかりか、無理に積み上げた場合には下の方の包装袋が破袋することが多い。
また、包装時に脱気工程を有する脱気減圧包装とも異なる。あらかじめ脱気したものは脱酸素後の脱気が著しく、カチカチになり、破袋、シール不良の原因となることが多い。
【００２７】
本発明における整形包装の一例として、軟包装袋に精米等の穀類を減圧下、少なくとも１気圧未満の状態で充填・包装し、開封部を密封した後、軟包装袋に小孔を１個以上穿け、該小孔から空気を自然に流入させ、軟包装袋内の気圧を大気圧とした後、再度該小孔をシール等により閉塞する工程からなる包装方法を例示することができる。
【００２８】
また、上記のような減圧包装装置を用いない場合、充填後の軟包装袋の形状とほぼ等しい、例えば縦と横と高さの寸法を有する、長方形の上部が開口した木製、プラスチック製、金属製の剛性の整形ホルダーを予め作製しておき、この整形ホルダー内にて軟包装袋に米を充填後、可及的に空気を排除して開封部を密閉する工程からなる包装方法を例示することができる。
【００２９】
【実施例】
以下に、実施例を掲げて本発明をさらに具体的に説明するが、本発明の技術的範囲はこれら実施例に限定されるものではない。
（実施例１）
透気度８０００秒の通気性包材に収納された、主成分として還元鉄粉を脱酸素組成物とする脱酸素剤（空気容量２５００ｃｃ対応品）と共に、精米直後の秋田こまち（米粒食味値８０）５ｋｇを精米直後に、ＯＰ／ＮＹ／ＰＥ／ＬＬＤＰＥからなる複合バリアフィルム（酸素透過度２５ｃｃ／ｍ²／２４ｈｒ、透湿度２ｇ／ｍ²／２４ｈｒ、厚み１００μｍ）で製袋した軟包装袋に充填し、脱気密封した。密封後、軟包装袋に小孔を１個穿け、該軟包装袋内の気圧を大気圧とした（この時、包装袋内の空気容量は２１００ｃｃであった）後、再度該小孔をシールにより閉塞する整形包装を行った。この整形包装後の軟包装袋をパレット上に１５段積み上げて貯留搬送したが、その間積み上げた軟包装袋の崩れ・転倒等はなく、また、破袋するものも見られなかった。
【００３０】
上記精米が充填された軟包装袋は約４８時間で脱酸素状態になり、３ヶ月保存後開封し手に取ったところ、見た目では緩く固まっていた米粒がさらさらと一粒毎に分離し、精米時の良質米の香りがした。開封直後及び開封２日後にこの精米を炊飯したところ、両者とも精米直後の炊飯米と同様な優良米の香りと呈味があった。
【００３１】
（比較例１）
実施例１において、負圧下に開封部を密封後、軟包装袋に小孔を穿つことなく減圧包装をしたままのものを用いる他は実施例１と同様に行った。この軟質包装袋をパレット上に１５段積み上げて貯留搬送したが、その間積み上げた軟包装袋の崩れ・転倒等はなく、また、破袋するものも見られなかったが、３ヶ月保存後に開封し手に取ったところ、米粒同士が岩おこし状に堅く固まり、精米時の良質米の香りは維持されているものの、外観及び触感において商品価値を喪失したものになっていた。
【００３２】
（比較例２）
脱酸素剤による空気中の酸素の吸着を予め見込んで、整形包装することなく、含気包装すること以外は実施例１と同様に行った。この軟質包装袋をパレット上に１５段積み上げようとしたが、６〜７段積み上げたところで不安定となり、崩れてしまうことが多く、また、崩れないように両側にホルダーを設けて１５段積み上げたところ一番下の軟質包装袋が破袋した。
【００３３】
（比較例３）
軟質包装袋内が１５時間及び１２０時間で脱酸素状態になるように、脱酸素剤の用量が調節されたものを用いた他は実施例１と同様に行った。３ヶ月保存後開封したところ、両者とも精米時の良質米の香りが消え、炊飯米も精米直後の良質米の香り及び呈味が失われていた。
【００３４】
（実施例２）
整形包装として、縦と横と高さの寸法がそれぞれ８×２８×４０ｃｍの長方形の上部が開口したプラスチック製の剛性整形ホルダーをもちい、この整形ホルダー内にて軟包装袋に良質米５ｋｇを充填後、可及的に空気を排除して開封部を密閉する以外は、実施例１と同様に行った。
【００３５】
上記精米が充填された軟包装袋は約５０時間で脱酸素状態になり、３ヶ月保存後開封したところ、実施例１の場合に比べて少し劣るものの、精米時の良質米の香りがした。開封直後及び開封２日後にこの精米を炊飯したところ、実施例１の場合に比べて少し劣るものの、両者とも精米直後の炊飯米と同様な優良米の香りと呈味があった。
【００３６】
【発明の効果】
本発明によると、殺虫、酸化防止等の従来の脱酸素剤を用いた効果の他に、精米等の充填された軟質包装袋の開封後及び炊飯時において、包材からの異臭の付加がなく、精米等が乾燥しておらず、精米時の良質米の香りのみならず、精米時の米粒の食味の保持が約６ヶ月間は可能となる。また、精米等を包装した枕状の軟包装袋の貯留・搬送の際に、例えばパレットに１０〜１５段積み上げての貯留・搬送に際して、積み上げた米袋が崩れて転倒したり、積み上げられた包装袋の一番下のものが破袋することがなく、産地直送形態の、貯留・搬送にも優れた包装形態の精米直後の米等の穀類の実用的な鮮度保持が可能となる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for maintaining the freshness of packaged cereals using cereals such as rice immediately after milling together with an oxygen scavenger.
[0002]
[Prior art]
Conventionally, a storage bag in which an oxygen scavenger is sealed in a corner of a storage bag for gas-barrier cereals (Japanese Utility Model Publication Nos. 59-143971 and 60-50171), and a storage bag for cereals, etc. Consists of gas barrier outer bag and oxygen permeable inner bag, put oxygen scavenger between outer bag and inner bag, and store stored items such as grains while leaving oxygen scavenger in storage bag A storage bag (Japanese Patent Laid-Open No. 63-67275) that can be taken out from the inside, and a storage bag for cereals, etc., are composed of a gas barrier inner bag and a relatively strong, sun-blocking kraft paper A storage bag containing an oxygen scavenger and an oxygen detector in an inner bag so that the oxygen detector can be visually confirmed from a window provided in the outer bag (Japanese Patent Laid-Open No. 61-203378). )It has been known.
[0003]
In addition, food such as potato chips, rice, and wheat is stored in a sealed bag made of plastic film that is degassed and filled with a chemical that absorbs oxygen and has a function of generating carbon dioxide. It is known that carbon dioxide gas suppresses external deformation of the sealed bag (Japanese Patent Laid-Open No. 4-201878).
[0004]
In addition, a flaky inorganic additive is added to polyethylene, the flaky inorganic additive enters the gaps between the polyethylene molecules, and the grains are put into a bag formed of a material with the gaps narrowed. A packaging method is known in which a vacuum degree is maintained so as not to be deformed after packaging by placing it in a vacuum packaging machine or by putting an oxygen scavenger in the bag and packaging (Japanese Patent Laid-Open No. Hei 3-162268). Issue gazette).
[0005]
Furthermore, a substantially non-breathable packaging material together with an oxygen scavenger formed by sealing cereals in a breathable packaging material having an oxygen scavenger composition with a Gurley air permeability (JISP 8117) of 200-100,000 seconds / 100 ml of air, or A method for controlling pests of cereals is known which is sealed in an airtight container and kept at 5 to 20 ° C. with an oxygen concentration of 0.1% or less to kill the pest eggs attached to cereals and prevent hatching after opening (special No. 64-7739).
[0006]
On the other hand, with recent changes in the rice distribution channel, the rice is in a unit of 5 kg, 10 kg, etc., in a soft package (flexible pack) with a resin material with a large number of small holes drilled in advance to give air permeability However, since these soft-wrapped rice has many small holes, no oxygen scavenger has been used.
[0007]
[Problems to be Solved by the Invention]
Recently, due to the increasing consumer preference to eat really delicious rice, soft wrapping of rice of specific varieties and specific production areas, in some cases right after milling of high quality rice of specific producers in units of 5 kg, 10 kg, etc. There are also an increasing number of sales methods for direct delivery and delivery from consumers to consumers. However, there was a problem that the quality of high-quality rice deteriorated a little before opening the packaged rice and cooked rice, and the flavor and the like were not different from those of ordinary over-the-counter sales, and the merit of direct delivery from the production area was not utilized .
[0008]
The present inventors examined the application of oxygen scavengers from the viewpoint of maintaining the freshness of good quality rice immediately after rice polishing, and the scent of good quality rice during rice polishing after opening and during rice cooking disappeared, Compared to the case where it becomes tasteless compared to the taste of rice grains, or the bad smell from the packaging material is added to the packaged polished rice, for the purpose of antioxidant, insecticidal, sterilization, etc. of grains with ordinary oxygen scavengers, It was found that there are various problems that need to be solved regarding the quality of polished rice. In addition, when storing and transporting pillow-shaped soft packaging bags packed with milled rice, for example, when storing and transporting 10 to 15 tiers of pallets, the stacked rice packaging bags collapse and fall, or the stacked rice It turned out that there was a big problem in practice that the bottom of the packaging bag broke.
[0009]
The object of the present invention is to solve all the above-mentioned problems related to quality such as rice milling and practical problems at the time of storage and transport, and to maintain excellent freshness of grains such as rice immediately after milling in a packaging form using an oxygen scavenger. It is to provide a method.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, we conducted intensive research on the type and performance of soft packaging bag packaging materials, the conditions for using oxygen scavengers, the packaging method of soft packaging bags during filling of milled rice, etc. It has been found that it is possible to maintain excellent freshness of cereals such as rice immediately after milling for the first time when adopting specific combinations such as specific use conditions of oxygen scavenger, specific packaging method of soft packaging bag at filling The present invention has been completed.
[0012]
That is, the present invention, the cereals, together with a deoxygenating agent, with the following oxygen permeability 30cc / m ² / 24hr, the flexible packaging bag comprising a moisture permeability 10g / m ² / 24hr or less than the thickness 40μm of the multilayer barrier film After packaging under reduced pressure, sealing the opening, making a small hole in the flexible packaging bag, setting the atmospheric pressure in the flexible packaging bag to atmospheric pressure, and then closing the small hole again, It is related with the freshness maintenance method of cereals, such as rice immediately after milling, characterized by performing and making it a deoxygenation state for 24 to 96 hours.
[0013]
Also, the present invention, the cereals, together with a deoxygenating agent, with the following oxygen permeability 30cc / m ² / 24hr, the flexible packaging bag comprising a moisture permeability 10g / m ² / 24hr or less than the thickness 40μm of the multilayer barrier film Using a rigid shaping holder, after filling rice in a soft packaging bag, shaping the packaging consisting of a step of sealing out by removing air as much as possible, and deoxidizing in 24 to 96 hours It relates to a method for maintaining the freshness of cereals such as rice immediately after milling.
[0014]
Furthermore, the present invention provides a freshness maintaining method using an iron-based oxygen absorber stored in a breathable packaging material having an air permeability of 3000 to 12000 seconds, and A freshness maintaining method using an oxygen agent containing an adsorbent such as 0.05 to 5% by weight of activated carbon, and the multilayer barrier film has a thickness of 40 to 150 μm and at least a polypropylene film layer and / or an aluminum foil layer It is related with the freshness maintenance method of cereals using what does not have an oxidation smell.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, cereals include rice, barley (including bare barley), wheat, rye, corn, corn, mackerel, horse mackerel, maize, bean mainly composed of soybeans, and buckwheat. It can be illustrated. In the present invention, a solid food material whose quality deteriorates due to oxidation of dried rice cake, tea or the like is also referred to as cereal for convenience.
[0016]
The method for maintaining freshness of the present invention is particularly suitable for rice immediately after milling, more preferably high-quality rice with a grain taste value of 70 or more, and this packaging keeps the freshness of the milled rice as it is after opening and until cooking. It was confirmed that it would sag. The rice grain taste value is an index representing the taste of rice, which is measured by a taste analyzer and the taste value of standard rice is 70.
[0017]
In the present invention, the oxygen scavenger is a composition in which a composition that absorbs oxygen by contact with air is stored in a packaging material such as a breathable sachet or a small container. Examples of such a composition include iron, carbonization, and the like. Reducing properties such as iron powders such as iron, reducing inorganic salts such as sulfites and ferrous salts, polyphenols such as hydroquinone, catechol, pyrogallol and gallic acid, reducing sugars such as glucose, ascorbic acid and erythorbic acid Examples include those containing a reducing agent such as polyhydric alcohol as the main active ingredient, among which iron-based deoxygenated compositions containing iron powder and an electrolyte, such as iron powder and metal halide, are preferred.
[0018]
The oxygen scavenger should be used in a state in which heat generation by the oxygen scavenger is suppressed so that the inside of the soft wrapping bag after shaping and packaging such as cereals will be in the oxygen scavenging state for 24 to 96 hours, preferably 24 to 48 hours. is necessary. When the deoxygenated state is obtained in less than 24 hours, the quality of cereals such as milled rice is degraded by the heat generated by the deoxygenation reaction. Moreover, when using a deoxidation agent on the conditions over 96 hours to be in a deoxygenation state, there exists a possibility that the quality of cereals, such as a rice mill, may deteriorate before it becomes a deoxygenation state.
[0019]
As the oxygen scavenger, in addition to the oxygen scavenging composition, those containing 0.05 to 5% by weight of an adsorbent such as activated carbon and zeolite can be used. If what contains 0.05-5 weight% activated carbon as an oxygen scavenger is used, in addition to the unpleasant odor of cereals, the oxidization odor derived from a multilayer barrier film can also be deodorized.
[0020]
It is preferable to store the deoxygenated composition in a breathable packaging material having an air permeability of 3000 to 12000 seconds. When an oxygen scavenger containing, for example, an iron-based oxygen scavenging composition is applied to a breathable packaging material having an air permeability of 3000 to 12000 seconds to a soft packaging bag that is shaped and packaged after filling 2 to 10 kg of polished rice, Becomes deoxygenated in 24-96 hours.
[0021]
Here, the air permeability means the Gurley-type air permeability of the air-permeable packaging material. Specifically, as the air-permeable packaging material having an air permeability of 3000 to 12000 seconds, a porous material (polyethylene terephthalate / polyethylene) is used. Examples thereof include a resin film made of / water / oil resistant paper / porous polyethylene.
[0022]
In the present invention, the multilayer barrier film is a packaging material of the flexible packaging bag, the oxygen permeability of 30cc / m ² / 24hr or less, preferably below 20cc / m ² / 24hr, moisture permeability 10g / m ² / 24hr or less , preferably 5g / m ² / 24hr or less in thickness 40μm or more, preferably can be used for 40 to 150. When the oxygen permeability is more than 30cc / m2 / 24hr, oxygen penetrates into the flexible packaging bag, it difficult to hold the deoxygenated state, also, those oxygen permeability of less than 20cc / m ² / 24hr is A deoxygenated state can be reliably achieved. Further, when the moisture permeability exceeds 10g / m ² / 24hr, or moisture in the flexible packaging bag causing lowering the freshness of intruding cereals as humidity, moisture milled rice such conversely to escape rice etc. Although dried so that the problems such as stickiness of the cooked rice is eliminated occurs, moisture permeability are the following 10g / m ² / 24hr is almost no such fear. And if the thickness of the multilayer barrier film is less than 40 μm, there is a risk of insufficient strength as a packaging material, and there is a risk that soft packaging bags may be damaged or pinholes may occur in the distribution process. However, it is hard and difficult to handle, and the material cost is high.
[0023]
As the material of the multilayer barrier film in the present invention, biaxially stretched polypropylene (OP), polyvinylidene chloride coated biaxially stretched polypropylene (KOP), aluminum (Al) such as aluminum foil and aluminum vapor deposition, stretched nylon (ON), Polyvinylidene chloride coated stretched nylon (KON), nylon (NY), unstretched polypropylene (CPP), polyethylene terephthalate (PET), polyvinylidene chloride coated polyethylene terephthalate (KPET), polyethylene (PE), polyvinylidene chloride coated polyethylene (KPE) ), Linear low density polyethylene (LLDPE) and the like. Specific examples of the laminated structure include ON / PE, KPET / PE, KON / PE, KOP / PE, KOP / NY / PE / LLDPE, PET / PE / paper / E, ON / PE / paper / PE, KPET / PE / paper / PE, KON / PE / paper / PE, KOP / PE / paper / PE, paper / PE / ON / PE, paper / PE / KPET / PE, Paper / PE / K Coat ON / PE, Paper / PE / KOP / PE, Paper / PE / Vinylidene Chloride / PE, PET / PE / Al / PE, ON / PE / Al / PE, OP / PE / Al / PE And multilayer barrier films such as OP / NY / PE / LLDPE, and multilayer barrier films such as PET / PE / Al / PE, KOP / NY / PE / LLDPE, OP / NY / PE / LLDPE, etc. Film is desirable.
[0024]
In addition to the above, the properties required for the multilayer barrier film in the present invention include good sealing properties and no oxidation odor. When the stored cereals are required to be particularly fresh in flavor, such as good quality rice immediately after milling, it is desirable to use a non-oxidizing odor as the multilayer barrier film, Is also called a lamellar odor or a poly odor, and is caused by thermal deterioration of a plastic melted at the time of laminating in the production process of a multilayer barrier film, and refers to a strange odor caused by an oxide of a film polymer.
[0025]
In the present invention, the soft packaging bag is also called a flexible pack, and means a packaging bag in which grains are stored in a bag formed of a packaging material made of a multilayer barrier film, unlike a container whose shape is fixed in advance.
[0026]
In the present invention, shaped packaging means that air between grains such as the gap between rice grains remains, but excess air in other bags is expelled as much as possible so that the soft packaging bags are almost filled with grains. Packing means a packaging method that does not collapse when, for example, 10 to 15 layers are stacked.
When the oxygen scavenger is applied to this shaped package, oxygen that occupies 20% of the air present in the package bag is absorbed. Therefore, this shaped package is different from the conventional aerated package. In aerated packaging, immediately after packaging, for example, 10 to 15 stacks may become unstable and may collapse or fall, and if stacked, the lower packaging bag may break. Many.
Moreover, it differs from the deaeration pressure reduction packaging which has a deaeration process at the time of packaging. Degassed in advance is significantly deaerated after deoxygenation, and becomes ticked, often causing broken bags and poor seals.
[0027]
As an example of shaped packaging in the present invention, a soft packaging bag is filled and packaged with grains such as milled rice under reduced pressure at a pressure of less than 1 atm. After sealing the opening, one or more small holes are formed in the flexible packaging bag. An example of the packaging method includes a step of making a hole, allowing air to naturally flow from the small hole, and setting the atmospheric pressure in the flexible packaging bag to atmospheric pressure, and then closing the small hole again with a seal or the like.
[0028]
In addition, when not using the vacuum packaging device as described above, the shape of the soft packaging bag after filling is substantially the same as the shape of the flexible packaging bag, for example, a wooden, plastic, metal with a rectangular top opening that has vertical, horizontal, and height dimensions. An example of a packaging method comprising a step of preparing a rigid shaping holder made in advance, filling the flexible packaging bag with rice in this shaping holder, and sealing the unsealed portion by eliminating air as much as possible be able to.
[0029]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the technical scope of the present invention is not limited to these examples.
Example 1
Akita Komachi (rice grain taste value 80) immediately after milling together with an oxygen scavenger (air capacity 2500 cc compatible product) containing reduced iron powder as a main component in a deoxygenating composition housed in a breathable packaging material with an air permeability of 8000 seconds ) immediately rice to 5kg, OP / NY / PE / LLDPE a composite barrier film (oxygen permeability 25cc / m ² / 24hr, moisture permeability 2g / m ² / 24hr, the soft packaging bag bag making the thickness 100 [mu] m) Filled and degassed and sealed. After sealing, a small hole is made in the flexible packaging bag, the atmospheric pressure in the flexible packaging bag is set to atmospheric pressure (the air capacity in the packaging bag was 2100 cc at this time), and the small hole is sealed again. The plastic packaging was closed by The shaped and packed soft packaging bags were stacked and transported in 15 layers on the pallet, but the stacked soft packaging bags were not collapsed or overturned during that time, and there were no broken bags.
[0030]
The soft wrapping bag filled with the above polished rice was deoxygenated in about 48 hours, opened for 3 months after storage and picked up by hand. The smell of good quality rice from time. When this rice was cooked immediately after opening and 2 days after opening, both had the same aroma and taste of good rice as the rice just after polishing.
[0031]
(Comparative Example 1)
In Example 1, the same procedure as in Example 1 was performed, except that the unsealed portion was sealed under a negative pressure, and then the soft packaging bag was used without being punctured without a small hole. The soft packaging bags were stacked and transported in 15 layers on the pallet, but the stacked soft packaging bags did not collapse or fall during that time, and there were no broken bags, but they were opened after storage for 3 months. When picked up, the rice grains were hardened in a rock shape, and the scent of good quality rice during milling was maintained, but the commercial value was lost in appearance and touch.
[0032]
(Comparative Example 2)
In the same manner as in Example 1, except that oxygen adsorption in the air by the oxygen scavenger was anticipated in advance, and air packaging was performed without shaping packaging. I tried to stack 15 layers of this soft packaging bag on a pallet, but when it was stacked 6 to 7 stages, it became unstable and often collapsed, and it was stacked with holders on both sides to prevent it from collapsing. However, the bottom soft packaging bag broke.
[0033]
(Comparative Example 3)
The same procedure as in Example 1 was performed except that the oxygen-adsorbing agent was adjusted so that the inside of the flexible packaging bag was deoxygenated in 15 hours and 120 hours. When opened for 3 months, both of them lost the scent of good quality rice during milling, and the cooked rice had lost the scent and taste of good quality rice immediately after milling.
[0034]
(Example 2)
For plastic packaging, use a plastic rigid plastic holder with a rectangular top with vertical, horizontal and height dimensions of 8 x 28 x 40 cm, and fill the flexible packaging bag with 5 kg of good quality rice. Then, it carried out like Example 1 except excluding air as much as possible and sealing an opening part.
[0035]
The soft packaging bag filled with the above polished rice was deoxygenated in about 50 hours and opened after being stored for 3 months. As a result, although it was slightly inferior to the case of Example 1, there was a scent of good quality rice during polishing. When this rice was cooked immediately after opening and 2 days after opening, although both were slightly inferior to the case of Example 1, both had the same fragrance and taste of good rice as the rice just after polishing.
[0036]
【The invention's effect】
According to the present invention, in addition to the effects of using conventional oxygen scavengers such as insecticide and antioxidant, there is no addition of off-flavors from the packaging material after opening a soft packaging bag filled with polished rice or during cooking. The polished rice is not dried, and not only the scent of good quality rice at the time of polishing but also the preservation of the taste of the rice grain at the time of polishing can be maintained for about 6 months. In addition, when storing and transporting pillow-shaped soft packaging bags packed with polished rice, etc., for example, when storing and transporting 10 to 15 tiers on a pallet, the stacked rice bags collapse and fall or are stacked The bottom of the bag does not break, and it is possible to maintain the practical freshness of cereals such as rice immediately after milling in a packaging form that is excellent in storage and transport in the form of direct delivery.

Claims

Cereals, together with a deoxygenating agent, with the following oxygen permeability 30cc ^/ m 2 ^/ 24hr, the flexible packaging bag comprising a moisture permeability ^10g / m 2 / 24hr or less double layer over the thickness 40μm of the barrier film, packaged under vacuum Then, after sealing the opening, a small hole is made in the flexible packaging bag, and after the atmospheric pressure in the flexible packaging bag is set to atmospheric pressure, the packaging is performed again by closing the small hole for 24 to 96 hours. A method for maintaining the freshness of cereals, characterized in that it is in a deoxygenated state.

Cereals, with oxygen scavenger, oxygen permeability 30cc / m ^２2 / 24 hr or less, water vapor transmission rate 10 g / m ^２2 Shaped packaging consisting of a process of sealing a flexible packaging bag composed of a multilayer barrier film with a thickness of 40 μm or less of 24 hours or less, using a rigid shaping holder, and excluding air as much as possible after sealing. A method for maintaining the freshness of cereals, characterized in that it is deoxygenated in 24 to 96 hours.

The method for maintaining freshness of cereals according to claim 1 or 2, wherein the oxygen scavenger is an iron oxygen scavenger housed in a breathable packaging material having an air permeability of 3000 to 12000 seconds.

The method for maintaining cereal freshness according to any one of claims 1 to 3, wherein the oxygen scavenger contains 0.05 to 5 wt% of an adsorbent.

The method for maintaining freshness of cereals according to any one of claims 1 to 4, wherein the multilayer barrier film has a thickness of 40 to 150 µm, includes at least a polypropylene film layer and / or an aluminum foil layer, and has no oxidation odor.

The method for maintaining freshness according to any one of claims 1 to 5, wherein the cereal is rice immediately after milling.