JP2004033092A - Method for ameliorating harsh taste of vegetable estrogen derivative, natto or natto food using the method and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for ameliorating the harsh taste of a vegetable estrogen derivative, comprising a new structure enabling resolving or reducing especially the harsh taste derived from the vegetable estrogen derivative with respect to use as a medicinal action reinforcement material on the protein food material of the vegetable estrogen derivative, to provide Natto(fermented soybeans) or Natto food using the method and to provide a method for producing the Natto or the Natto food. <P>SOLUTION: This method for ameliorating the harsh taste of the vegetable estrogen derivative comprises fermentation-treating the vegetable estrogen derivative-containing protein food material in a condition of being mixed with a proper quantity of calcium to be used together. As a result, the harsh taste caused by the remaining vegetable estrogen derivative is resolved or reduced by masking with the calcium. <P>COPYRIGHT: (C)2004,JPO

Description

【００１１】
こうした社会的要請に呼応して、植物性エストロゲン誘導体、特に「大豆イソフラボン」に着目し、そのイソフラボン含量が高い大豆の胚軸（胚芽）が、豆乳などの大豆を原料とする各種食品の製造において、その副産物として、大豆の脱皮を行う時、大豆胚軸を主体とし、これに少量の、−般に１５％程度の破砕された大豆の種子の子葉部の細砕粒が混ざった大量の細粒マスが発生しているにも拘わらず、長年の間、邪魔者扱いされて廃棄物として経費を掛けて処分するか、あるいは、それらの一部が、抽出、精製等の製造コストが嵩むことを前提にして有機溶剤によって処理し、大豆サポニン分を抽出して特定の分野に限定された高価な商品としてしか利用されていなかったものを、大豆を発酵させた納豆のように、納豆菌や麹薗、テンペ菌（クモノスカビ）によって発酵させ、大豆そのものではなく、大豆胚軸だけによる発酵生産物（乾燥物や乾燥・粉砕物も含まれている。）を作り上げ、発酵製品としてそのまま市販したり、各種食品製造の素材として添加、利用する外、錠剤に成形し、あるいは糖衣錠等のコーティング剤としても利用したり、その乾燥物をほぐして粒状マスとするか、あるいは、粉砕して粉状として保存や運搬、取扱い等の便を良くし、家畜の飼料等としての利用も可能とするようにした発明が、既に特公平７−６１２４１号「大豆胚軸の発酵生産物並びにその製造方法」として提案されている。
【００１２】
この発明のものは、大豆の胚軸マスだけを納豆菌や麹菌、テンペ菌によって発酵させ、既存の大豆食品である納豆やテンペのような性状のものとなし、身体に良い生理作用をもたらすことが知られる大豆胚軸含有の大豆サポニン（イソフラボン）の薬理作用を直接利用可能となるようにした、言わば納豆における大豆の代わりに大豆胚軸マスだけを使って発酵させた発酵生産物にするとしたものであって、この大豆サポニン（つまりイソフラボン）は煮たり焼いたりしてもその苦味（えぐ味）が無くならいため、従来まではそのままで食用としての利用ができなかったものを、納豆菌、麹菌、テンペ菌の発酵作用によって「大豆胚軸の強い苦味は殆どなくなり、渋味は完全に除去される」（同公報第３頁第５欄第２０〜２１行に記載）として、各種食用に供しようとするものである。
【００１３】
ところが、追試によれば、大豆胚軸マスを納豆菌等によって発酵させただけのものでは、依然として苦味（えぐ味）は残り、そのまま発酵生産物とした性状のものについては言うに及ばず、各種食品、例えば通常の納豆に添加したものとしても、とても食用に耐え得るものとするには程遠く、したがって、上記公報に開示されたとおりの発酵生産物は、到底実用上での利用を期待することが困難なものであると結論せざるを得ないものであることが確認された。
【００１４】
この結論は、同公報第３頁第５欄第２１〜２７行に記載の「多量に含有する有用な大豆サポニンは殆ど分解されることなく高濃度に残存し而も蛋白質、炭水化物の分解により消化性と味覚の改善され、更には、アミラーゼ、プロテアーゼなど消化などに関与する各種酵素が含有されたそのまゝ食用に適し或いは各種の食品製造の素材として広い分野に利用し得る発酵生産物が得られ、上記の要望を満足することができた。」にあるとおり、発酵過程において殆どの大豆サポニンは分解されずに残るとしている事実からして当然の帰結であって、大豆サポニン成分がそのまま残置する以上、それら残存大豆サポニン（植物性エストロゲン誘導体）由来の苦味（えぐ味）感が除去または軽減化される筈もなく、追試によって当該発明による発酵生産物に依然として苦味（えぐ味）が残るという確認を待つまでもなく、当該公報記載箇所の存在からだけでも、上記した結論は明確に裏付けらているとすることができ、そして、この結論を覆すに足る科学的な解明記載箇所やデータ等は同公報に一切示されていない。
【００１５】
この発明は、同じく大豆胚軸および胚軸マスを含む植物性エストロゲン誘導体の食品としての有効利用につき、その原材料である大豆を素材とする食品の代表格であって、世界にも類を見ない機能性食品としての評価が高い納豆の製造、販売を長年に渡って生業とする者の一人として、極めて強い関心を抱くことになったことから、逸早く植物性エストロゲン誘導体の納豆への添加、利用についての開発、研究に着手する中、上記した先行技術に提案のある利用は、理論上からも、また追試による確認結果からしても不可能であるとの結論に達し、それ以外の有効利用のための解決手段を官民共同研究の形で模索を続け、長年に渡る試行錯誤と幾多の試作実験とを繰り返してきた結果、茲にきて、遂に大豆胚軸および／または胚軸マスに含まれる植物性エストロゲン誘導体を食用に十分耐え得るだけのものに食味感を改善し、単独にでも、あるいは納豆に代表されるタンパク質食品素材に添加、利用することが可能であり、それがまた、広く大豆胚軸および／または胚軸マス以外の植物、例えばその他のマメ科（クズ、葛根、グワーオクルア等）が含む植物性エストロゲン誘導体、あるいはそれらから抽出した成分としての植物性エストロゲン誘導体と、納豆をはじめとするタンパク質食品素材との組み合せにおいても有効となることを確認し得ることとなった新規な構成からなる植物性エストロゲン誘導体のえぐ味改善方法、ならびにそれを利用した納豆または納豆食品、およびその製造方法を完成したものであり、以下では、具体的な実施例と共に、その構成の詳細を説示していくことにする。
【００１６】
【発明の構成】
この発明の基本をなす植物性エストロゲン誘導体のえぐ味改善方法は、基本的に、植物性エストロゲン誘導体を含有するタンパク質食品素材を、適量のカルシウム分が併用、添加された状態で発酵処理することにより、当該発酵処理によっても殆ど分解しない状態で残存することとなる植物性エストロゲン誘導体に起因して発生するえぐ味感を、カルシウム分によってタンパク質分解酵素の活性化を図り、タンパク質食品素材内のアミノ酸含量を高めてマスキングして解消または軽減化するようにした構成を要旨とする植物性エストロゲン誘導体のえぐ味改善方法である。
【００１７】
この発明には、上記のとおりの構成を基本とする植物性エストロゲン誘導体のえぐ味改善方法と同様の技術的思想からなり、それ自体には植物性エストロゲン誘導体を含有しないか、不足するかするタンパク質食品素材の、植物性エストロゲン誘導体配合による薬理作用を補強、増強する際にも有効となるようにした次のとおりの構成を要旨とする植物性エストロゲン誘導体のえぐ味改善方法が包含されている。　　　　　　　　　　　　　　　　　　　　　　　　　　　　　即ち、タンパク質食品素材に薬理作用補強物質として植物性エストロゲン誘導体またはその含有物質を配合する際に、適量のカルシウム分を併用、添加して発酵処理し、カルシウム分によってタンパク質分解酵素の活性化を図り、タンパク質食品素材内のアミノ酸含量を高めてマスキングし、タンパク質食品素材によって形成される食品から、当該発酵処理によっても殆ど分解しない状態で残存することとなる植物性エストロゲン誘導体由来によるえぐ味感を解消または軽減化するようにした構成を要旨とする植物性エストロゲン誘導体のえぐ味改善方法である。
【００１８】
植物性エストロゲン誘導体またはその含有物質には、植物性エストロゲン誘導体、即ちイソフラボン成分を含有する大豆胚軸および／または胚軸マスに代表されるマメ科（クズ、葛根、グワーオクルア等）植物をそのままか、適宜乾燥、あるいは乾燥、粉砕したものが含まれる外、それら植物等から抽出、精製した成分としての植物性エストロゲン誘導体が包含されており、それらは、単独でか、あるいは適宜選択、組み合わせた植物性エストロゲン誘導体またはその含有物質としてタンパク質食品素材（味噌、しょう油、納豆等）に、その適量がタンパク質食品素材の発酵処理前の加水、加熱処理等と同時に処理されるようにする適宜段階に配合するのを基本としているが、植物等から抽出、精製した成分としての植物性エストロゲン誘導体、即ちイソフラボン製剤を採用するような場合であれば、タンパク質食品素材の発酵処理前でありさえすれば、特にその配合段階が制限されることはない。
【００１９】
この植物性エストロゲン誘導体の適量に対し、カルシウム分の添加割合は、その添加対象とする植物性エストロゲン誘導体の種類によってもえぐ味（苦味）感が微妙に異なってしまうことから、それら植物性エストロゲン誘導体全般に渡って必ずしも共通した範囲としての値を明確化することが難しいが、植物性エストロゲン誘導体１ｇに対し、カルシウム分は１ないし１０ｇの範囲を目安とするようにし、食味や外観、経済性等を考慮し、納豆に適用できる範囲としては通常１．２５前後の割合が最適（但し、人の食味感に大いに左右される。）のようである。
【００２０】
なお、カルシウム分としては、食品添加物として認められている炭酸カルシウムが、貝殻カルシウム、珊瑚カルシウム、卵殻カルシウム、骨カルシウムの四種類があることから、一応それらに限定され、上記添加割合を適用する際、カルシウムの分子量が４０であるのに対し、炭酸カルシウムのそれが１００であることを勘案し、貝殻カルシウム他の添加分量が決定されるようにしなければならない。
【００２１】
上記の条件を整えてカルシウム分の所定量を添加した植物性エストロゲン誘導体を配合してなるタンパク質食品素材は、目的とする発酵食品が味噌、しょう油、納豆等といった大豆食品の種類に応じた発酵手段によって発酵されることにより、添加されたカルシウム分によってタンパク質分解酵素の活性作用が高められ、その作用によってタンパク質食品素材、例えば納豆中のアミノ酸含量が高まる結果、植物性エストロゲン誘導体由来によるえぐ味成分（苦味成分）がマスキングされてしまい、食用とする際に不快感として敬遠されるえぐ味（苦味）は、実用に供するに何等支障を来さない範囲まで確実に除去または大巾に軽減化されてしまうことが確認されたものである。
【００２２】
【関連する発明１】
この発明の基本をなす上記したとおりの構成からなる植物性エストロゲン誘導体のえぐ味改善方法を利用して得られる次のとおりの構成の納豆が、この発明には包含されており、その構成は、含水処理に続いて加熱処理を施してなる大豆と植物性エストロゲン誘導体またはその含有物質とに適量のカルシウム分を添加した上、種菌を接種して発酵、熟成するようにし、添加した植物性エストロゲン誘導体由来のえぐ味を改善したものとして得るようにしたことを要旨とする納豆である。
【００２３】
そして、上記構成によって示される納豆は、より具体的には、含水処理に続いて加熱処理を施してなる大豆と胚軸および／または胚軸マスとに適量のカルシウム分を添加した上、種菌を接種して発酵、熟成するようにし、添加した胚軸および／または胚軸マスが含有する植物性エストロゲン誘導体由来のえぐ味を改善したものとして得るようにした構成からなる納豆ということができる。
【００２４】
こうして得られる納豆は、所謂通常の糸引き納豆として供される外、場合によってはそのまま納豆に塩をまぶすか、あるいは、納豆を一旦洗浄してぬめりを取ってから塩をまぶし、むしろやざるの上で干したり、その他公知の機械的手段によって乾燥する等して、昔から各地で製造されてきた、所謂干し納豆とすることもでき、また、それら干し納豆を粉砕して粉末納豆となし、そのままか、その他食品添加用のものとすること等も当然可能とするものである。
【００２５】
【関連する発明２】
さらに、この発明には、上記したとおりの構成からなる納豆に関連し、その納豆を製造する方法も包含していて、次のとおりの構成からなるものである。　即ち、大豆と適量の胚軸および／または胚軸マスとを十分給水して膨潤化するようにした含水処理、その後、水切り処理を行い、膨潤化させた大豆と、同じく膨潤化してなる適量の胚軸および／または胚軸マスとに適量のカルシウム分を添加した上、水蒸気加熱か加水加熱かの何れかの手段によって所要時間煮込むようにする加熱処理、加熱処理したものを放冷または強制冷却して発酵に適した温度と含水率とに調整してから、種菌を接種して所要時間発酵、熟成するようにする発酵処理、以上の処理を継続、実施することにより、添加した胚軸および／または胚軸マスが含有する植物性エストロゲン誘導体由来のえぐ味感を、カルシウム分によってタンパク質分解酵素の活性化を図り、大豆および胚軸および／または胚軸マス内のアミノ酸含量を高めてマスキングし、納豆食品から胚軸および／または胚軸マスが含有する植物性エストロゲン誘導体由来のえぐ味感を解消または軽減化するようにした構成を要旨とする納豆の製造方法がそれである。
【００２６】
この納豆の製造方法は、従前からの伝統的な納豆（糸引き納豆）の製造方法、つまり、水洗いした大豆を３倍程度の水に２０時間程度浸漬し、大豆が吸水して２倍強の重量になるようにする浸漬工程、浸漬工程を終えた大豆をざるにあけ、水を切りをした上で、鍋にそれら大豆と水とを入れて約３時間程度、大豆が水面から出てしまって不均一な煮込み状態にならないよう水加減に注意して煮るか、あるいは、加熱水蒸気で約３ないし４時間程度の間に渡って蒸し煮する加熱処理工程、加熱処理されて蒸し上がった大豆は、一旦放冷または強制冷却して発酵に適した温度と含水率とに調整してから、溜まった水滴に大豆が触れて通気性を疎外されないよう、予め底にガーゼを３、４重にして敷いた容器の中に種菌と共に入れてしまう仕込み工程、その後、容器の中で４０度程度の温度を維持するようにし、概ね１日間程度を経過させて発酵してから、約１週間程度が目安として冷蔵庫に入れて熟成させ、旨みを増すようにする発酵、熟成工程を基本とするだけのものであり、それらの過程の中で、適量の植物性エストロゲン誘導体と、それに対する所定割合のカルシウム分とが、所定の段階にまごうことなく配合または添加されるようにしなければならない。
【００２７】
したがって、糸引き納豆とは別の、例えば浜松の浜納豆や京都の大徳寺納豆、一休寺納豆、あるいは奈良の浄福寺納豆のような塩辛納豆（納豆菌ではなく麹菌で発酵させた塩味の乾燥納豆）に分類される納豆の製造であれば、当然、上記糸引き納豆のための製造方法とは違い、それら塩辛納豆としての伝統的な製造方法によるものとなることは言うまでもないことである。
【００２８】
なお、この製造法における含水処理および加熱処理は、大豆に適量の胚軸および／または胚軸マスを配合してなるものについて実施する外、含水処理および加熱処理の中、少なくとも含水処理については、大豆と胚軸および／または胚軸マスとを個別に実施する（但し、加熱処理についても個別の実施とするときは、大豆と胚軸および／または胚軸マスとの何れか一方に適量のカルシウム分を添加しておくようにする）ようにし、その後の発酵処理に入る前の段階に、それら処理を終えた大豆に、同じくそれら処理を終えてなる適量の胚軸および／または胚軸マスを配合するようにして実施することができ、この発明の納豆の製造方法では、何れによるものも包含されている。　　　　　　　　　　　　　　　　　　以下、上記までの構成がより明確なものとなるようにするために、具体的な事例を取り上げて説明を加えていくことにする。
【００２９】
【実施例】
先ず、大豆１．２ｋｇに胚軸２４０ｇを加え、井水に２０時間浸漬させた上で、それらをよく水切りしてからセイロに入れ、加熱水蒸気で約４時間程度の間に渡って蒸煮し、それら蒸煮大豆１００ｇ、蒸煮胚軸２０ｇ当たりに対し、１ｇとなる割合でカルシウム剤を添加して均一に混合してから、納豆菌を噴霧後、従前どおり、略４０°Ｃに維持するようにした発酵室にて約２４時間を掛けて発酵させ、約５０ｇずつ納豆パックに小分けしてなるこの発明の納豆を試作した。なお、カルシウム剤としては、シジミ貝殻カルシウムを添加している。
【００３０】
上記のとおり工程を経て試作した納豆パック入り納豆（約５０ｇ）を、各納豆１パック当たり２倍量、即ち１００ｇの蒸留水を加え、室温下で略３０分間、ガラス棒を用いて撹拌することによって納豆表面のエキス成分を抽出し、遠心分離（１，２０００ｒｐｎ×５ｍｉｎ）によって得られた上清を納豆抽出液とした上、以下するとおりの遊離アミノ酸の定量およびプロテアーゼ活性の測定を行ってみた。
【００３１】
遊離アミノ酸の定量は、納豆抽出液を３０倍希釈した溶液を試料として全自動アミノ酸分析装置（ＪＥＯＬ，ＪＬＣ３００）を用いてを行い、また、プロテアーゼ活性の測定方法は、図２に示したとおりであって、１０倍に希釈した納豆抽出液を酵素液とし、２％ミルクカゼンを基質として加えてから、４０°Ｃで５分間、１０分間、２０分間および４０分間の区分毎に夫々反応させた後、各区分毎の試料に、夫々０．１Ｍトリクロロ酢酸を加えて撹拌後、遠心分離によって得られた上清を０．４５μｍのフィルター濾過し、濾液１ｍｌに０．４Ｍ炭酸ナトリウム溶液５ｍｌおよびフェノール試薬１ｍｌ加え、充分撹拌して４０°Ｃで２０分間放置した後、６６０ｎｍで吸光度を測定した。
【００３２】
先ず、カルシウム剤添加によるところの発酵に与える影響を調べるために、これら納豆抽出液のｐＨを測定したところ、夫々６．８０および６．９０であった。このことから、カルシウム剤を添加しても殆どｐＨには影響を与えないことが分かった。次に、遊離アミノ酸含量を比較したところ、カルシウム剤を添加することにより、表２のデータが示すとおり、遊離アミノ酸含量が２５％増加することが分かった。
【００３３】
【表２】

【００３４】
一方、表２のデータが示しているとおり、カルシウム剤添加によって遊離アミノ酸含量が異なったことから、プロテアーゼ活性にも違いがあるのではないかとの推測から、納豆抽出液のプロテアーゼ活性の比較を行ったところ、その結果、図３のグラフに示すとおり、対照区分に比べてカルシウム剤添加区分の活性が同様に高という事実が判明した。
【００３５】
以上の測定結果から、先行する技術のように、単に胚軸および／または胚軸マスを発酵処理しただけでは、それらが多量に含有する有用なイソフラボン、即ち植物性エストロゲン誘導体は、その発酵処理によっても殆ど分解されることなく高濃度に残存する結果、植物性エストロゲン誘導体由来のえぐ味（苦味）が当然の如くに除去も軽減化もされずに残ってしまうのに対し、発酵処理の際に、胚軸および／または胚軸マスのような多量に有用な植物性エストロゲン誘導体を含有するタンパク質食品素材に所定割合でカルシウム分を添加したものとしておくことにより、発酵過程のタンパク質発酵食品素材中の遊離アミノ酸含量を確実に増加させることができ、その遊離アミノ酸含量の増加により、発酵処理によっても殆ど分解されることなかった植物性エストロゲン誘導体に起因するえぐ味（苦味）感がマスキングされてしまい、人の食味として災いするえぐ味（苦味）が除去または大巾に軽減化されてしまうという、かって知られることのなかった新たな事実を確認することができた。
【００３６】
【作用効果】
以上のとおり、この発明による植物性エストロゲン誘導体のえぐ味改善方法は、それ自体植物性エストロゲン誘導体を含有するタンパク質食品素材、およびそれ自体には植物性エストロゲン誘導体を含有しないか、不足するかするタンパク質食品素材の、植物性エストロゲン誘導体による薬理作用を補強、増強目的で、タンパク質食品素材に植物性エストロゲン誘導体またはその含有物質を配合したものの、発酵処理によっても殆ど分解されることなく高濃度に残存することとなる植物性エストロゲン誘導体由来のえぐ味（苦味）を、これまで全く知られていなかった、植物性エストロゲン誘導体に対して所定割合でカルシウム分を添加したものとして発酵処理することにより、その過程でタンパク質発酵食品素材中の遊離アミノ酸含量を増加させ、その遊離アミノ酸含量の増加によって植物性エストロゲン誘導体由来のえぐ味（苦味）感をマスキングしてしまうという手段で略確実に解消または軽減化することができるようにするという極めて大きな特徴を発揮するものとなる。
【００３７】
また、それを利用した納豆または納豆食品、およびその製造方法では、人体に不可欠の必須アミノ酸群を多く含み、それが生理活動を活発化してすると同時に、脳細胞の活性化を促すといわれ、世界からはソイ・ビーン・チーズとまで称される程に栄養豊かで、整腸作用やある種の腸内有害細菌やウィルスに対する対抗性、さらには制ガン作用についての臨床データまであって、それ自体でも十分に秀れた滋養強壮食と言える納豆に、更年期障害をはじめ、骨粗鬆症やガンや心臓病、その他様々な病気の予防やその軽減化にも有効性があるとして注目が集まる植物性エストロゲン誘導体（フィトエストロゲン＝植物由来の女性ホルモン様物質）、特に大豆胚軸や胚軸マスに多く含まれているイソフラボンを配合し、薬理作用を補強した高機能性食品として提供するに際し、発酵化しても殆ど分解されずにそのまま残存する植物性エストロゲン誘導体由来のえぐ味（苦味）を略確実に解消または軽減化してなる高機能性食品としての納豆を実現することができるという秀れた効果が得られるものとなる。
【００３８】
叙述の如く、この発明の植物性エストロゲン誘導体のえぐ味改善方法、ならびにそれを利用した納豆または納豆食品、およびその製造方法は、その新規な構成によって普く所期の目的を達成可能にするものであり、人々の関心が強く健康管理に向けられ、それに便乗した大量の情報が交錯する中でも、極めて安全で信頼性の高い有効な食品群として評価されている大豆食品、特に薬理作用に注目が集まる植物性エストロゲン誘導体を多く含有するとして知られるその胚軸や胚軸マスそのもの、あるいはそれを配合したタンパク質発酵食品の摂取を、極めて違和感のないものとして食用にすることができるようにしたことから、一般消費者からは固よりのこと、特に納豆業界に従事する人々からは、新たな商品を得て業界の活性化に寄与するものになるとして高い評価がなされることとなり、広く普及、拡大していくことになるものと予想される。
【図面の簡単な説明】
図面は、この発明を代表する幾つかの具体的な実施例を示したものである。
【図１】代表的な大豆イソフラボンの分子構造を示したものである。
【図２】プロテアーゼ活性の測定方法を示す概念図である。
【図３】カルシウム剤添加によるプロテアーゼ活性の増加を表したグラフである。[0001]
[Object of the invention]
The present invention relates to the use of phytoestrogen derivatives, which are attracting attention as naturally occurring estrogen (female hormone) -like substances, that is, isoflavones, as pharmacological action-enhancing substances for protein food materials. Novel composition that makes it possible to eliminate or reduce the astringency derived from phytoestrogenic derivatives even when blending and using hypocotyl and / or hypocotyl trout of soybean with various protein food materials And a natto or natto food using the same, and a method for producing the same.
[0002]
[Prior art]
Japan, which has become one of the longest living countries in the world, has continued to maintain a fairly stable standard of living even during the long economic recession following dramatic recovery and development. One of the concerns of the people, despite the issues of ensuring and expanding their living base in the future, is one of the concerns of everyday health care, especially the environment and abundant food groups that are affected in everyday life. There are matters related to the effects on the human body from such as, while paying attention to national projects related to smoke emission from garbage incinerators and vehicles, emission control, food additives and pesticide regulations, quality labeling obligations, etc. Individuals are willing to cooperate, such as separating garbage, stopping cars from idling, and switching to hybrid cars. On the other hand, they are closely monitoring the variety of foods they consume on a daily basis.
[0003]
Due to the rising awareness of consumers, the collection of information related to health foods in particular is extremely active, and the food industry is steadfast and a large amount of information continues to flow from various media without stopping day and night. From the flooding information, consumers need to be able to recover and sustain their normal mind and body, all of which are necessary and indispensable. These phenomena seemed to remind people of the illusion that they might end up, and these phenomena instead resulted in anxiety and suspicion for consumers, and as a result, many people's food choices The trend is to avoid chemical foods and synthetic foods as much as possible without being misled by flooding information, and to turn to natural foods that use as little additives and pesticides as possible. In the industry, there is a tendency to actively respond to such demands, and even natural foods, which have been regarded as having sufficient nutritional value so far, are factors that excel in bioactive functions etc. There has been a movement to create new functional foods by adding.
[0004]
Among the natural foods in Japan, natto, a soybean food, is one of the foods that has always attracted attention as one of the world's top foods. According to recent statistics, about 4.5 billion, equivalent to 37 per year per capita per year. This natto can be said to be a national diet correctly, and is a fermented food made by applying natto bacteria to soybeans called "meat of the field". It is also known that the content of vitamin B group (B1, B2, B6, B12, pantothenic acid, nicotinic acid, etc.) is high, and especially B2 reaches 5 times that of soybean, which means that Bacillus natto grows It is thought that when the vitamins are synthesized.
[0005]
One example of comparing the health status of countries around the world is the determination based on the amount of calcium intake, and according to the data, Japanese are the lowest in developed countries. However, comparing the fracture rate of the femoral neck, which is most susceptible to osteoporosis, between Japanese and Europeans, American women who take twice as much calcium as Japanese women have three times the fracture rate. In addition to the results that are high, there are also data that Japanese people have less menopausal symptoms and lower mortality from breast cancer and prostate cancer than European and American people, The human diet, especially the diet incorporating natto, has an exquisite balance of nutrient balance: first, the starch quality of rice (rice) is 75%, natto protein is 35%, and fat is 20%. It has been pointed out that the amino acid composition is also a very good combination of complementing each other, and one or two (Indonesia They have been eating fermented soybean natto (similar to soy bean cheese in Europe and the United States) that has only soybean fermented product "Tempe" and Nepal's soybean fermented product "Kinema" with koji mold. The ideal dietary habit, especially natto, is based on the report that the digestion and absorption of 65% in the case of boiled beans is greatly improved by the action of natto to about 90%. Some people are trying to find out how much soy foods are consumed.
[0006]
In recent years, natto, which has such an excellent effect, has also been screened in order to remove small debris and equalize the size of crushed soybeans in the production process of split natto in order to respond to consumers' high-class taste. Treatment began to take place, during which time most of the hypocotyls and hypocotyl trout (a large by-product of the hypocotyl mixed with the cotyledon of crushed soybean seeds and crushed seed coat granules) passed through the sieve Since it is later discarded, the high-class natto such as the recent discount natto contains almost no hypocotyl or hypocotyl trout.
[0007]
However, in the last 15 to 16 years, a soy-containing substance called isoflavone, a phytoestrogen derivative (phytoestrogen = plant-derived female hormone-like substance) contained in soybean, has been welcomed until then. “Aku”, which was not a substance, is the source of so-called “egumi”, which has attracted attention as an effective material for women's diseases such as osteoporosis, menopause, and breast cancer. It has been reported that it is effective in preventing and alleviating heart disease and various other diseases in addition to menopause, osteoporosis and cancer.
[0008]
Strictly speaking, this phytoestrogen derivative is a substance that has an action similar to that of estrogen, which is produced by the action of intestinal bacteria from precursors contained in vegetables (soy, yam, parsley, celery, fennel, guarokulua, etc.). There is isoflavone as a typical one of them. It is a component contained in leguminous plants (soybean, kudzu, kakkon, guaua oclua, etc.), and acts similarly to estrogen (a kind of female hormone) produced in the body. Estrogens, which are also called phytoestrogens, as described above, exhibit an estrogenic effect by binding to estrogen-receptors in the body, and this plant estrogen derivative (isoflavone) However, unlike synthetic estrogens, there is much estrogen secretion in the human body Has the effect of suppressing it and increasing it when there is little. It has an effect similar to that of female hormones (estrogens) on female diseases, and its action is very mild, one-thousandth of female hormones. In addition to the extremely safe pharmacological action expected below, it also has physiological actions such as carcinogenesis suppression, antioxidation and antibacterial properties.
[0009]
This phytoestrogen derivative, particularly “soy isoflavone”, has the molecular structure shown in FIG. 1 in the form of Daidzin (Genizin), Genistin (Genistin), Glycitin (Glycitin), and malonyl glycosides, acetyl glycosides and aglycones thereof. As a general term, twelve types have been confirmed at present, and as shown in Table 1 below, the content of isoflavones is particularly high in the hypocotyl (germ) of soybean. Or, effective use of phytoestrogen derivatives containing hypocotyl trout as foods, that is, use as an active substance as it is, or use as an active substance that enhances or adds pharmacological action in combination with various foods is greatly expected. I have.
[0010]
[Table 1]

[0011]
In response to these social demands, we focused on phytoestrogenic derivatives, especially "soy isoflavones," and the soybean hypocotyl (germ) with a high isoflavone content was used in the production of various foods using soybeans such as soymilk. As a by-product, when soybeans are molted, a large amount of fine particles mainly composed of soybean hypocotyls and mixed with a small amount, generally about 15%, of finely ground particles of crushed soybean seed cotyledons. Despite the occurrence of trout, for many years they are treated as disturbers and disposed of at a cost as waste, or some of them increase the production cost of extraction, purification, etc. It was treated with an organic solvent on the premise that the soybean saponin component was extracted and used only as an expensive product limited to a specific field.However, like natto fermented soybean, natto bacteria and koji Sono, Ten Fermented by fungi (Lucyer), fermentation products (including dried and dried / crushed products) are produced using only the soybean hypocotyl, not the soybean itself. In addition to being used as a raw material, it is used as a tablet, or it is also used as a coating agent for sugar-coated tablets, etc., or the dried product is loosened to a granular mass, or pulverized to be stored and transported as a powder, An invention that improves convenience of handling and the like and enables use as feed for livestock and the like has already been proposed as Japanese Patent Publication No. 7-61241, "A fermented product of soybean hypocotyl and a method for producing the same". .
[0012]
The present invention ferments only the hypocotyl mass of soybean with natto, koji mold, and tempeh fungus, does not have the properties of existing soybean foods such as natto and tempeh, and has a good physiological effect on the body. To make the pharmacological action of soybean saponin (isoflavones) containing soybean hypocotyl known directly available, so to speak, a fermented product fermented using only soybean hypocotyl mass instead of soybean in natto This soybean saponin (i.e., isoflavones) has not lost its bitterness (egg taste) even when boiled or baked. "The strong bitterness of the soybean hypocotyl is almost eliminated and the astringency is completely eliminated" by the fermentation of Tempeh bacteria (described in the same publication, page 3, column 5, lines 20 to 21). It is intended to be subjected to various types of food.
[0013]
However, according to the supplementary tests, it was found that fermentation of soybean hypocotyl trout by natto bacteria or the like still leaves bitterness (egg taste), not to mention fermented products as they are. Even if it is added to food, for example, normal natto, it is far from being very edible, so that the fermented product as disclosed in the above publication is expected to be used in practical use at all. Has been concluded to be difficult.
[0014]
The conclusion is that the useful soybean saponin contained in a large amount remains at a high concentration without being substantially decomposed and is digested by the decomposition of proteins and carbohydrates as described in p. 3, column 5, lines 21 to 27. A fermentation product having improved properties and taste, and further containing various enzymes such as amylase and protease that are involved in digestion, etc., is obtained as it is, which is suitable for edible use or can be used in various fields as a material for producing various foods. As a result, most of the soybean saponins remained in the fermentation process without being decomposed, which was a natural consequence, and the soybean saponin component was left as it was. As a result, the bitterness due to the residual soybean saponin (phytoestrogen derivative) cannot be eliminated or reduced. Without waiting for the confirmation that the substance still has bitterness (egg taste), the above conclusion can be clearly supported by the existence of this publication alone, and overturns this conclusion. No sufficient scientific elucidation, description, data, etc. are given in the publication.
[0015]
The present invention relates to the effective use of phytoestrogen derivatives including soybean hypocotyl and hypocotyl trout as food, and is a representative of soybean-based food as its raw material, and is unique in the world. As one of the people who has been producing and selling natto, which has a high reputation as a functional food, for many years, has become very interested in it, so we quickly added and used phytoestrogen derivatives to natto. During the development and research on, we concluded that the use proposed in the prior art described above was impossible from a theoretical point of view and from the results of additional tests, and that other effective use Has been sought for solutions to this problem in the form of public-private joint research, and after many years of trial-and-error and numerous trial production experiments, it has finally been included in soybean hypocotyls and / or hypocotyl masses. It is possible to improve the taste of phytoestrogen derivatives to those that can withstand edible foods, and to use them alone or in protein food materials such as natto. Plants other than soybean hypocotyls and / or hypocotyl trout, such as phytoestrogenic derivatives contained in other legumes (e.g., kuzu, kakkon, guao krua), or phytoestrogen derivatives as components extracted therefrom; A method for improving the savory taste of a phytoestrogenic derivative having a novel structure, which has been confirmed to be effective even in combination with a protein food material, and natto or natto food using the same, and production thereof The method has been completed, and the details of its configuration will be described below along with specific examples. To Kukoto.
[0016]
Configuration of the Invention
The method for improving the astringency of phytoestrogen derivatives, which is the basis of the present invention, is basically a fermentation treatment of a protein food material containing phytoestrogens derivatives, in which an appropriate amount of calcium is added and added. The astringency caused by the phytoestrogen derivative, which hardly decomposes even after the fermentation treatment, is used to activate the proteolytic enzymes by the calcium content, and to improve the amino acid content in the protein food material. This is a method for improving the astringency of a phytoestrogen derivative, which has a constitution in which elimination or reduction is achieved by masking by increasing the amount of phytoestrogen.
[0017]
The present invention comprises the same technical idea as the method for improving the astringency of phytoestrogen derivatives based on the above-mentioned constitution, and contains no or deficient phytoestrogens themselves. A method for improving the astringency of a botanical estrogen derivative, which has the following constitution, which is also effective in reinforcing and enhancing the pharmacological action of a food material by blending the botanical estrogen derivative, is included. That is, when a phytoestrogen derivative or a substance containing the same is added to a protein food material as a pharmacological action-enhancing substance, an appropriate amount of calcium is used in combination, added and fermented, and the proteolytic enzyme is activated by the calcium. Masks the protein food material by increasing the amino acid content, and eliminates the astringent taste derived from phytoestrogenic derivatives that remain in the food formed by the protein food material in a state that is hardly degraded by the fermentation treatment Alternatively, the present invention is a method for improving the astringency of a phytoestrogen derivative, which has a constitution that is reduced.
[0018]
As the phytoestrogen derivative or a substance containing the same, a phytoestrogen derivative, that is, a leguminous plant (e.g., kudzu, kakkon, guaua krua) represented by soybean hypocotyl and / or hypocotyl trout containing an isoflavone component, In addition to those which are appropriately dried, or dried and pulverized, they include phytoestrogen derivatives as components extracted and purified from these plants and the like. An appropriate amount of estrogen derivative or its containing substance is added to protein food materials (miso, soy sauce, natto, etc.) at an appropriate stage so that an appropriate amount of the estrogen derivative is processed at the same time as adding water before fermentation, heating, etc. Phytoestrogen induction as a component extracted and purified from plants, etc. , I.e. in the case that employs the isoflavone formulation, so long a pre-fermentation of the protein food material, not particularly that the compounding stage is limited.
[0019]
The proportion of calcium added to the appropriate amount of the phytoestrogen derivative depends on the type of phytoestrogen derivative to which the phytoestrogen derivative is added. Although it is difficult to clarify the value as a common range over the entirety, the calcium content should be in the range of 1 to 10 g per 1 g of the phytoestrogen derivative, and the taste, appearance, economy, etc. In consideration of the above, the ratio which can be applied to natto is usually about 1.25 (however, it greatly depends on the taste of human beings).
[0020]
In addition, as the calcium content, calcium carbonate recognized as a food additive, shell calcium, coral calcium, eggshell calcium, there are four types of bone calcium, for the time being limited to them, apply the above addition ratio At this time, considering that the molecular weight of calcium is 40 and that of calcium carbonate is 100, it is necessary to determine the added amount of shell calcium and the like.
[0021]
Under the above conditions, a protein food material comprising a phytoestrogen derivative to which a predetermined amount of calcium has been added is used as a fermentation means according to the type of soybean food such as miso, soy sauce, natto, etc. By the fermentation, the added calcium content enhances the activity of proteolytic enzymes, and the action increases the amino acid content in protein food materials, for example, natto. The bitterness (bitterness component) is masked, and the savory taste (bitterness) that is avoided as an unpleasant sensation when edible is reliably removed or greatly reduced to the extent that it does not hinder practical use. It has been confirmed that it will.
[0022]
[Related invention 1]
Natto having the following constitution obtained by using the method for improving the astringency of phytoestrogen derivatives having the constitution as described above, which forms the basis of the present invention, is included in the present invention, and the constitution is as follows: After adding an appropriate amount of calcium to the soybean and the phytoestrogen derivative or a substance containing the soybean that have been subjected to a heat treatment following the hydration treatment, inoculate a seed fungus, ferment and mature, and add the added phytoestrogens derivative. It is a natto whose gist is to improve its taste.
[0023]
The natto represented by the above configuration is more specifically added with an appropriate amount of calcium to the soybean and the hypocotyl and / or the hypocotyl mass obtained by subjecting the soybean and the hypocotyl and / or the hypocotyl trout to a heat treatment following the water-containing treatment. It can be said that the fermented soybean has a configuration in which inoculation is performed, fermentation and ripening are performed, and an improved astringency derived from a phytoestrogen derivative contained in the added hypocotyl and / or hypocotyl trout is obtained.
[0024]
The natto obtained in this way is not provided as so-called ordinary thread-drawn natto, but in some cases, natto may be coated with salt, or natto may be washed once, slicked and then coated with salt. Dried on, or dried by other known mechanical means, etc., can be so-called dried natto, which has been manufactured in various places from long ago, and also crushed dried natto into powdered natto, Naturally, it can be used as it is or for other food additives.
[0025]
[Related invention 2]
Furthermore, the present invention relates to a natto having the above-described configuration, and also includes a method for producing the natto, and has the following configuration. That is, the soybean and a proper amount of hypocotyl and / or hypocotyl trout are sufficiently supplied with water so as to be swelled, and then subjected to drainage treatment to obtain a swelled soybean and an appropriate amount of swelling. Heat treatment in which an appropriate amount of calcium is added to the hypocotyl and / or hypocotyl mass, and then simmered for a required time by either steam heating or hydrothermal heating, and the heat-treated material is left to cool or forcedly cooled. After adjusting to a temperature and a water content suitable for fermentation, fermentation for inoculating the inoculum for a required time, fermentation to ripen, and continuing the above processing, by adding the hypocotyl and And / or by activating a proteolytic enzyme by a calcium content in the astringent taste derived from the phytoestrogen derivative contained in the hypocotyl trout, soybeans and the amino acids in the hypocotyl and / or hypocotyl trout A method for producing natto, which is characterized in that the amount is increased and masked to eliminate or reduce the astringency derived from the phytoestrogen derivative contained in the hypocotyl and / or hypocotyl from natto food. is there.
[0026]
This method of producing natto is a traditional method of producing natto (natto natto), i.e., soaking washed soybeans for about 20 hours in about three times the amount of water, soybeans absorb water, and slightly more than twice the amount of water. Soaking the soybeans after the immersion process and the immersion process to reduce the weight, draining the water, adding those soybeans and water to the pot, and soybeans come out of the water surface for about 3 hours. Boiled so that it does not become unevenly boiled or not, or boil for about 3 to 4 hours with heated steam, heat-treated soybeans Once cooled or forcibly cooled to adjust the temperature and moisture content suitable for fermentation, soak the soybeans in the accumulated water droplets and apply gauze to the bottom three or four times in advance so that the air permeability is not alienated. The brewer who puts the seed bacteria in the container After that, keep the temperature of about 40 degrees in the container, ferment it after about 1 day, then put it in a refrigerator for about 1 week as a guide to ripen it to increase the flavor. Fermentation and maturation processes, and in those processes, an appropriate amount of a phytoestrogen derivative and a predetermined proportion of calcium are mixed or added without confusion at a predetermined stage. Must be done.
[0027]
Therefore, salty natto, such as Hamamatsu natto in Hamamatsu or Daitokuji natto, Ikkyuji natto in Kyoto, or Jofukuji natto in Nara, is different from thread-drawn natto. It goes without saying that, in the case of the production of natto classified as (natto), unlike the production method for the above-described natto, the traditional production method for salted natto is used.
[0028]
In addition, the water-containing treatment and the heat treatment in this production method are performed on a mixture of soybean and an appropriate amount of hypocotyl and / or hypocotyl mass. The soybean and the hypocotyl and / or the hypocotyl mass are individually performed (however, when the heat treatment is also performed separately, an appropriate amount of calcium is added to either the soybean and the hypocotyl and / or the hypocotyl mass. Before the fermentation process), before adding soybeans to the soybeans that have been subjected to the treatment, an appropriate amount of hypocotyls and / or hypocotyl masses that have also been subjected to the treatments. The method of producing natto of the present invention encompasses any of the methods. Hereinafter, in order to make the configuration described above clearer, specific examples will be taken up and added.
[0029]
【Example】
First, 240 g of hypocotyls were added to 1.2 kg of soybeans, immersed in well water for 20 hours, then drained well, put in a seiro, and steamed with heated steam for about 4 hours. A calcium agent was added at a rate of 1 g per 100 g of the steamed soybean and 20 g of the steamed hypocotyl, and the mixture was uniformly mixed. After spraying Natto, the temperature was maintained at about 40 ° C. as before. Fermentation was carried out in a fermentation room for about 24 hours, and a natto of the present invention, which was subdivided into natto packs of about 50 g each, was prototyped. As a calcium agent, squid shell calcium was added.
[0030]
The natto (approximately 50 g) in the natto pack prepared through the above-described process is added with twice the amount of distilled water per pack of natto, that is, 100 g of distilled water, and stirred at room temperature for about 30 minutes using a glass rod. The extract component on the surface of natto was extracted by centrifugation, and the supernatant obtained by centrifugation (1,2000 rpm × 5 min) was used as a natto extract, and the amount of free amino acids and the protease activity were measured as described below. .
[0031]
The amount of free amino acids was determined using a 30-fold diluted solution of natto extract as a sample and using a fully automatic amino acid analyzer (JEOL, JLC300). The method for measuring protease activity was as shown in FIG. Then, the natto extract diluted 10 times was used as the enzyme solution, and 2% milk kazen was added as a substrate. After reacting at 40 ° C for 5 minutes, 10 minutes, 20 minutes and 40 minutes, respectively. After adding 0.1 M trichloroacetic acid to each sample and stirring, the supernatant obtained by centrifugation was filtered through a 0.45 μm filter, and 5 ml of 0.4 M sodium carbonate solution and 1 ml of phenol reagent were added to 1 ml of the filtrate. After 1 ml was added, the mixture was sufficiently stirred and left at 40 ° C. for 20 minutes, and the absorbance was measured at 660 nm.
[0032]
First, in order to examine the effect of the addition of the calcium agent on fermentation, the pH of these natto extracts was measured to be 6.80 and 6.90, respectively. This indicates that the addition of the calcium agent hardly affects the pH. Next, when the free amino acid content was compared, it was found that the addition of the calcium agent increased the free amino acid content by 25% as shown in the data of Table 2.
[0033]
[Table 2]

[0034]
On the other hand, as shown in the data of Table 2, since the free amino acid content was different due to the addition of the calcium agent, it was presumed that there was a difference in the protease activity. As a result, as shown in the graph of FIG. 3, the fact that the activity of the calcium agent-added section was similarly higher than that of the control section was found.
[0035]
From the above measurement results, simply fermenting the hypocotyl and / or hypocotyl trout, as in the prior art, would result in useful isoflavones, i.e., phytoestrogenic derivatives, which are contained in large amounts, by fermentation. Remains at a high concentration without being substantially decomposed, so that the astringent taste (bitterness) derived from the phytoestrogen derivative remains without being removed or reduced as a matter of course. By adding a predetermined percentage of calcium to a protein food material containing a large amount of useful phytoestrogen derivatives such as hypocotyl and / or hypocotyl trout, the protein fermented food material in the fermentation process The free amino acid content can be reliably increased, and due to the increase in the free amino acid content, almost no decomposition occurs even by fermentation treatment. It is known that the taste of bitterness (bitterness) caused by phytoestrogen derivatives is masked, and the taste of bitterness (bitterness) that is harmful to humans is removed or greatly reduced. I was able to confirm new facts that did not exist.
[0036]
[Effects]
As described above, the method for improving the astringency of a phytoestrogen derivative according to the present invention is directed to a protein food material containing a phytoestrogen derivative per se, and a protein containing no or lacking a phytoestrogens derivative per se. For the purpose of reinforcing and enhancing the pharmacological action of phytoestrogen derivatives of food materials, phytoestrogen derivatives or their containing substances are blended with protein food materials for the purpose of enhancement, but remain in high concentration without being substantially decomposed even by fermentation treatment. The fermentation treatment of the astringent taste (bitterness) derived from the different phytoestrogen derivatives as a substance to which a certain amount of calcium was added to the phytoestrogens derivatives, which had never been known before, was used. Increases the free amino acid content in protein fermented food ingredients It has an extremely large characteristic that it can be almost certainly eliminated or reduced by means of masking the astringent (bitter) sensation derived from the phytoestrogen derivative by increasing its free amino acid content. It will be.
[0037]
In addition, natto or natto food using the same and its manufacturing method contain a large amount of essential amino acids essential for the human body, which is said to activate physiological activities and promote brain cell activation at the same time. Is so nutritious as to be called Soi Bean Cheese, and it has clinical data on intestinal action, resistance to certain intestinal harmful bacteria and viruses, and even anticancer action. But natto, which can be said to be an excellent nutritional tonic diet, is a phytoestrogen derivative that has attracted attention as being effective in preventing and alleviating various diseases, including menopause, osteoporosis, cancer and heart disease. (Phytoestrogens = plant-derived female hormone-like substance), especially isoflavones, which are often contained in soybean hypocotyls and hypocotyl trout, to enhance pharmacological action To provide natto as a highly functional food, which is almost completely eliminated or reduced in the garnish derived from a phytoestrogen derivative which is hardly decomposed even when fermented and provided as a food. The excellent effect that can be obtained is obtained.
[0038]
As described above, the method for improving the astringency of the phytoestrogen derivative of the present invention, and the natto or natto food using the same, and the method for producing the same can achieve the intended purpose by its novel constitution. In spite of the interest of people in health care and the large amount of information that has been piggybacked on it, attention has been paid to soy foods, which have been evaluated as an extremely safe, reliable and effective food group, especially pharmacological effects. Because the hypocotyl and hypocotyl trout itself, which is known to contain a large amount of phytoestrogenic derivatives, or the ingestion of protein-fermented foods that contain it, can be made edible as extremely uncomfortable. , From the general consumer, especially from those engaged in the natto industry, get new products and contribute to the vitalization of the industry High evaluation will be is made as would, widespread, is expected to be able to expand.
[Brief description of the drawings]
The drawings show some specific embodiments representative of the present invention.
FIG. 1 shows the molecular structure of a typical soy isoflavone.
FIG. 2 is a conceptual diagram showing a method for measuring protease activity.
FIG. 3 is a graph showing an increase in protease activity due to the addition of a calcium agent.

Claims (12)

By fermenting a protein food material containing a phytoestrogen derivative with an appropriate amount of calcium in combination and added, the phytoestrogen derivative will remain in a state where it is hardly decomposed by the fermentation process. Vegetable characteristics characterized by the fact that the astringent taste generated due to calcium is activated by proteolytic enzymes, the amino acid content in the protein food material is increased, and masking is eliminated or reduced. A method for improving the astringency of estrogen derivatives. When compounding a phytoestrogen derivative or a substance containing it as a pharmacological action enhancing substance in a protein food material, an appropriate amount of calcium is used together, added and fermented to activate proteinases by the calcium content. Masks by increasing the amino acid content in the food material, and eliminates or reduces the astringency derived from phytoestrogenic derivatives, which remain from the food formed by the protein food material in a state that is hardly decomposed even by the fermentation treatment A method for improving the savory taste of a phytoestrogenic derivative, wherein After adding an appropriate amount of calcium to soybean and a phytoestrogen derivative or a substance containing the same, which are subjected to a heat treatment following the hydration treatment, inoculate a seed fungus, ferment and ripen, and add the added phytoestrogen derivative. Natto, characterized by being obtained as an improved taste of its origin. After adding an appropriate amount of calcium to the soybean and the hypocotyl and / or the hypocotyl mass obtained by subjecting the soybean and the hypocotyl and / or the hypocotyl trout which have been subjected to a heat treatment to a treatment subsequent to the water-containing treatment, the inoculated fungus is fermented and matured, and the added hypocotyl and / or Alternatively, natto characterized by being obtained as an improved astringency derived from a phytoestrogen derivative contained in the hypocotyl trout. A natto food product obtained by drying the natto according to claim 3 or 4. A natto food product obtained by drying and pulverizing the natto according to any one of claims 3 and 4. A water-containing treatment in which soybean and an appropriate amount of hypocotyl and / or hypocotyl trout are sufficiently supplied to cause swelling, and then a draining treatment is performed to obtain a swollen soybean. And / or after adding an appropriate amount of calcium to the hypocotyl mass and heating the mixture for a required period of time by steam heating or water heating, allowing the heated mixture to cool or forcibly cool. After adjusting to a temperature and a water content suitable for fermentation, fermentation for inoculation with a seed fungus for a required time, fermentation to ripen, and continuing and carrying out the above-mentioned treatments, the added hypocotyl and / or The astringency derived from the phytoestrogen derivative contained in the hypocotyl trout is stimulated by calcium to activate the proteolytic enzymes, and the amino acid content in soybean and hypocotyl and / or hypocotyl trout is reduced. The production of natto according to claim 3 or 4, wherein the natto food is masked so as to eliminate or reduce the astringency of the hypocotyl and / or the phytoestrogen derivative contained in the hypocotyl trout from the natto food. Method. The method for producing natto according to claim 7, wherein the water-containing treatment and the heat treatment are performed on a mixture of soybean and an appropriate amount of hypocotyl and / or hypocotyl mass. Among the water-containing treatment and the heat treatment, at least the water-containing treatment is performed separately on the soybean and the hypocotyl and / or the hypocotyl mass (however, when the heat treatment is also performed separately, the soybean and the hypocotyl and / or Alternatively, an appropriate amount of calcium is added to either one of the hypocotyl masses), and before the fermentation process is started, soybeans that have been treated are also subjected to the same treatment. The method for producing natto according to claim 7, wherein an appropriate amount of hypocotyl and / or hypocotyl mass is added. 3. The method for improving the astringency of plant-derived estrogens according to claim 1 or 2, wherein the amount of calcium added is 1 to 10 g per 1 g of the phytoestrogen derivative. The natto or natto food according to any one of claims 3 to 6, wherein the calcium content to be added is 1 to 10 g per 1 g of the phytoestrogen derivative to be added. The method for producing natto according to any one of claims 7 to 9, wherein the calcium content to be added is 1 to 10 g per 1 g of the phytoestrogen derivative to be added.

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