JP4269682B2

JP4269682B2 - Raw chestnut with skin for heat processing, peeled chestnut manufacturing method, chestnut skin releasing method, and chestnut skin cutting device

Info

Publication number: JP4269682B2
Application number: JP2002572828A
Authority: JP
Inventors: 川本　　裕巳; 山崎　　勝也; 中村　　秀男; 健司伊藤
Original assignee: Kracie Foods Ltd
Current assignee: Kracie Foods Ltd
Priority date: 2001-03-15
Filing date: 2001-03-15
Publication date: 2009-05-27
Anticipated expiration: 2021-03-15
Also published as: JPWO2002074108A1; WO2002074108A1

Description

【０００１】
技術分野
本発明は、皮を剥いた天津甘栗などの、そのまま食することができる加熱加工栗の、長期保存中の変色を防止することができる加熱加工用皮付き生栗、皮付き生栗から栗皮を完全に剥皮し、剥皮後の保存中の変色を防止することができる剥き栗の製法、皮付き生栗果肉から栗皮を完全に簡単に剥皮することができる栗の皮遊離方法、及び栗の皮を栗果肉から完全に遊離するための栗皮切り込み装置に関する。
【０００２】
背景技術
従来より、焼き栗は、日本栗の焼き栗のみならず、中国栗を焼いた天津甘栗、西洋栗の焼き栗等、皮を剥きながら手軽に食べられる食品として広く親しまれている。また最近では天津甘栗を食べやすくするために、予め皮を剥いて耐熱性の袋に密封し、消費者がこの袋を開いてそのままつまんで食べることができるような商品が多数発売され、特許等も提案されている。例えば、登録実用新案第３０５１６１２号公報には、皮付きの原料天津栗を石焼釜で焼いた後、一晩冷却し、鬼皮、渋皮を除去し、凍結後加圧蒸煮して冷却し、その後栗を窒素ガスとともに耐熱性袋に充填密封して加熱殺菌する、袋入り皮むき天津甘栗が記載されている。
しかしながら、上記の方法で得られる袋入り皮むき天津甘栗は、長期保存中に栗果肉の色調が初期の黄色〜茶色系の色調から緑色〜黒色の色調に変色もしくは褐変し、外観を損ねて商品価値が低下するという問題がある。
【０００３】
また、皮むき袋入り天津甘栗は、原料となる皮付き生栗の品種、貯蔵条件、収穫時期などによって風味や変色の程度がばらつき、安定した品質が得られにくいという問題がある。
そこで、例えば特許登録第２５１６１４９号公報には、周年供給できる調理グリの製造法が開示されている。
この方法は、皮付きの生栗を一定期間冷蔵することによって甘さを増加させた後、凍結・冷凍貯蔵に移し、任意の時期に取り出して加圧湿熱によって調理することにより、調理栗の甘さを約３倍に増加させることができるものである。
しかしながら、この方法で得られる調理栗は、甘さを増加させることはできるものの、皮付きのまま冷凍してそのまま加圧湿熱調理するので、得られる調理栗は、渋皮や鬼皮が強固に栗果肉に密着し、剥皮しにくくなるとともに、皮付きのまま湿熱調理することによって皮部分の変色物質が栗果肉中に移行もしくは残留し、調理栗の保存中の変色が促進されるという問題がある。
更には、この方法では湿熱処理が必須であるので、水分や糖分を多く含む栗となってしまい、各種の栗調理品への利用がしにくいという問題もある。
【０００４】
また、栗の種類のうち、天津栗は、湿熱ではなく、焼いてから皮を剥くということと、欧州栗、日本栗に比べて品種の特性上、比較的皮が剥きやすいが、それでも完全に鬼皮、渋皮を取り除きにくいという問題があり、皮むき天津甘栗としたときに皮が残存して風味や外観を悪くするという問題がある。
そこで、栗の剥皮効率を改善する方法としては、例えば特開平１０−８４９２８号公報に記載の剥皮方法がある。この方法は、栗の座部に切り込みを入れてから酵素剤を含む水溶液に浸漬して酵素を果肉と渋皮との密着部分に作用させて軟弱化させ、水分の存在下で加熱加圧し、冷水中に放出して鬼皮と渋皮を除去する方法である。
しかしながら、この方法では、酵素の作用を確実に栗皮全周に行き渡らせるために、複数もしくは広範囲の切り込みが必要であるため、栗果肉が割れやすかったり、外観が悪くなるという問題がある。また、この方法で得られる剥き栗は、酵素剤特有の風味が加わったり、煮栗や蒸し栗様の水っぽい食感となり、焼き栗のような香ばしさを付与することができない。
【０００５】
また、栗の皮に切り目を入れる作業は、人手で行うと、栗の鬼皮が硬いために作業者の作業負担が重く、また切り目の入れ方が安定せず果肉部分に深く切り目が入りすぎて傷として残り、外観品質が低下する。そこで、自動化して安定的に切り目を入れることが量産化の点で望まれるが、そのような方法としては、例えば特公平３−４１９１号公報に記載の方法がある。
この方法は、無端状に連結し、開口部が下向けになるよう配置されたカップ群を走行させながらこのカップ内に収容された栗に下方から複数の回転刃を多段的に接触させ、回転刃の回転運動と走行コンベアの前進運動によって栗がランダムに回転し、栗表面の全面に切り込みを入れる方法である。
しかしながら、この方法では、栗の大きさのばらつきや、カップに収容された栗の方向によって回転刃の切り込み深さが異なり、またカップ内で栗が浮き上がって、切り込みが入らなかったり、逆に過剰に切り込みが入ったりする場合もあるので、切り込み状態にばらつきが生じ、これが調理栗の外観の低下につながったり、剥皮不良につながるという問題がある。
【０００６】
本発明は、このような事情に鑑みなされたものであって、その目的の第一は、そのまま食したり、各種の加工調理栗として用いることもでき、調理後長期保存した時に褐変が生じず、栗本来の色調と風味を有する調理栗を、栗の品種や収穫時期等にかかわらず安定して得ることができる加熱加工栗用の皮付き生栗を提供するにある。
また、目的の第二は、皮付き生栗から栗皮を完全に剥皮し、剥皮後の保存中の変色を防止することができる剥き栗の製法を提供するにある。
また、目的の第三は、皮付き生栗果肉から栗皮を完全に簡単に剥皮することができる栗の皮遊離方法を提供するにある。
また、目的の第四は、栗の皮を栗果肉から完全に遊離するための栗皮切り込み装置であって、栗の大きさ、形状、固定方向にかかわらず、栗皮に確実にかつ一定の深さで、所定の数の切り込みを安定して入れることができる栗皮切り込み装置を提供するにある。
【０００７】
発明の開示
本発明は、加熱加工に用いるための皮付き生栗であって、１〜３℃で６ヶ月以内、もしくは５〜１０℃で４ヶ月以内の保管により、該皮付き生栗の栗果肉中の糖度が１０〜２３°に設定されてなることを特徴とする加熱加工用皮付き生栗である。
また、本発明は、皮付き生栗を乾熱加熱後、栗表面温度を４０℃以上に保持した状態で剥皮することを特徴とする剥き栗の製法である。
また、本発明は、皮付き生栗が、１〜３℃で６ヶ月以内、もしくは５〜１０℃で４ヶ月以内の保管により、該皮付き生栗の栗果肉中の糖度が１０〜２３°に設定されてなる皮付き生栗であることを特徴とする剥き栗の製法である。
また、本発明は、乾熱加熱が、１５０〜２５０℃で１５分以内に行われることを特徴とする剥き栗の製法である。
また、本発明は、剥皮した後、引き続き−２０〜−４０℃雰囲気下で６時間以内に中心品温０℃以下となるよう凍結することを特徴とする剥き栗の製法である。
また、本発明は、皮付き生栗の栗皮に切り込みを刻設した後、該切り込み入り皮付き生栗を乾熱加熱し、栗皮を栗果肉から遊離させることを特徴とする栗の皮遊離方法である。
また、本発明は、皮付き生栗の栗皮に切り込みを刻設するに際して、切り込み深さが０．４〜０．７ｍｍ、切り込み長さが栗の最長径の５％以上の長さに設定されていることを特徴とする栗の皮遊離方法である。
また、本発明は皮付き生栗の栗皮に切り目を刻設するための栗皮切り込み装置であって、皮付き生栗の一部を露出するための栗受け孔が設けられた栗受けケースに皮付き生栗を載置する載置手段と、該載置手段により皮付き生栗を載置した栗受けケースを搬送するための搬送手段と、該搬送手段により搬送された栗受けケース内に載置された皮付き生栗を押圧するための押圧手段と、該押圧手段によって押圧され該栗受け孔から露出した皮付き生栗に当接して栗皮に切り込みを刻設するための切断手段と、該切断手段により切り込みを刻設された皮付き生栗を排出するための排出手段とを備えてなる栗皮切り込み装置である。
また、本発明は、押圧手段が、栗受けケース内に載置された皮付き生栗を個別に押圧する手段である栗皮切り込み装置である。
また、本発明は、押圧手段が、エアシリンダー駆動手段によって降下、上昇するエアシリンダーとコイルバネ抑え板とコイルバネと栗抑え板とからなり、該コイルバネと栗抑え板とが、栗受け孔内の皮付生栗を個別に押圧しうるよう、栗受け孔の数と位置に対応して個別に設けられてなる栗皮切り込み装置である。
また、本発明は、切断手段が、切断刃と該切断刃を把持するための切断刃ガイドとからなり、切断刃先端が栗皮の切り込み深さと略同一となるよう該切断刃ガイドから露出して把持されてなる栗皮切り込み装置である。
また、本発明は、皮付き生栗の栗皮に上記の栗皮切り込み装置を用いて切り込みを刻設した後、該切り込み入り皮付き生栗を乾熱加熱し、栗皮を栗果肉から遊離させることを特徴とする栗の皮遊離方法である。
【０００８】
すなわち、本発明者らは、従来の、剥皮した栗を包装容器に収容、密封し、レトルト殺菌などの加熱殺菌をする方法において、レトルト殺菌等の加熱加工を行うと、長期保存中に栗の色が変色し、外観を悪くするとともに、風味的にも好ましくないことから、加熱加工後の品質低下を防止する方法について検討を行った結果、まず原料となる皮付き生栗の保管条件によって変色が生じるのではないかと考え、原料の皮付き生栗の保管条件について検討を行った。
その結果、１〜３℃で６ヶ月以内、もしくは５〜１０℃で４ヶ月以内の保管により、該皮付き生栗の栗果肉中の糖度が１０〜２３°に設定されてなる皮付き生栗を、原料として用いるようにすると、栗の収穫時期や品種に係わらず、加熱処理後の長期保存中にも変色のない加熱加工栗を得ることができることを見出した。
【０００９】
更には、皮付きの生栗を完全に剥皮する方法として、皮付きの生栗を乾熱加熱した後の放置によって、一部遊離しかけていた鬼皮、渋皮が栗果肉に再度密着し、剥離しにくくなるのではないかと考え、皮付きの生栗を乾熱加熱後した後の放置条件について検討を行った結果、乾熱加熱を行った後、栗表面温度を４０℃以上に保持した高温状態のままで剥皮すると、鬼皮、渋皮が完全に栗果肉から遊離し、また、加熱処理後長期保存した調理栗の変色が防止されることを見出した。
【００１０】
そして、乾熱加熱を１５０〜２５０℃で１５分以内の高温短時間で行うと、更に鬼皮、渋皮が栗果肉から遊離し、剥皮がしやすくなること、また、加熱処理後長期保存した調理栗の変色が防止されることを見出した。
【００１１】
また、剥き栗を上記のように処理しても、長期保存中にはある程度変色の進行が認められることから、剥き栗の保管条件について検討を行った結果、乾熱加熱して剥皮した剥き栗を、引き続き−２０〜−４０℃雰囲気下で６時間以内に中心品温０℃以下となるよう急速凍結すると、加熱処理後長期保存した調理栗の変色が更に防止されることを見出した。
【００１２】
更には、皮付きの生栗の剥皮を完全に行うために、栗皮の果肉からの遊離方法について検討を行った結果、皮付き生栗の栗皮に切り込みを刻設した後、乾熱処理すると、切り込み部分から栗皮の遊離が栗全周に渡って広がり、栗皮を栗果肉から完全に遊離させることができ、その後軽く手で剥くなどの簡単な短時間処理によって確実に剥皮を行うことができることを見出した。
【００１３】
また、上記切り込みを入れる際に、確実に一定の深さで所定の数の切り込みを刻設できる装置について検討を行った結果、皮付き生栗を、皮付き生栗の一部を露出するための栗受け孔のある栗受けケースに入れて、この皮付き生栗を上方から押圧して、皮付き生栗の一部を栗受け孔から露出させ、この露出部分に対して、切断刃等で切断すると確実に切り込みが行えることを見出し、本発明に到達した。
特に、切断刃等で切断するに際して、切断刃の先端を切り込み深さと略同一となるよう露出して切断刃ガイドで把持した切断刃を用いると、一定の深さまでしか切断刃が栗露出部分に入らないので、より確実に切り込みが行えることを見出し、本発明に到達した。
また、上記皮付き生栗の押圧を、各皮付き生栗ごとに個別に行いうる押圧手段とすることにより、各皮付き生栗の大きさや、栗受け孔への入り方向にかかわらず、確実に各皮付き生栗を押圧できることを見出し、本発明に到達した。
【００１４】
発明を実施するための最良の形態
次に、本発明を詳しく説明する。
【００１５】
まず、原料となる皮付き生栗は、特に品種や大きさを限定するものではなく、一般に用いられているものから適宜選択して用いればよい。通常皮付き生栗は、イガから取り出されており、外層から順に鬼皮、渋皮、栗果肉からなる。
この発明は、特に天津甘栗のような、喫食者が皮をむいて食する焼き栗か、予め焼いた栗の皮をむいて耐熱性袋等に密封殺菌した調理栗に特に好適に用いられる。
【００１６】
次に、本発明の加熱加工に用いるための皮付き生栗は、栗果肉中の糖度が１０〜２３°のものを用いる。好ましくは、栗果肉中の総フェノール量が１〜２５ｍｇ％である。
すなわち、この条件よりも多いと、加熱加工後、保存した時に変色が生じる。逆にこの条件よりも少ないと、色調が白っぽくなり、また風味、食感が不良となる。
総フェノール量と糖度は、必ずしも相関しているものではない。
なお、総フェノール量、糖度はいずれも皮（鬼皮、渋皮）を取り除いた栗果肉全体の平均含有量を示す。
この条件の範囲となる皮付き生栗の保管条件は、１〜３℃保管では６ヶ月以内、５〜１０℃では４ヶ月以内とする。更には、皮付き生栗を包装して保管する場合には、通水性、通気性の良い包装体を用いることが望ましい。通水性、通気性の良い包装体としては、例えば、綿、麻、不織布等の通水性繊維や、通水性のない素材を通水しやすいように間隙を有する織物に加工したものや、孔を複数個設けたものが挙げられる。
中でも麻製の包装体は、多少の保管条件の変動、期間の変動によっても比較的長期間所期の品質（総フェノール量、糖度）が得られる点で好適である。
【００１７】
次に、本発明の剥き栗は、例えば、次のようにして得られる。
まず、好ましくは上記総フェノール量、糖度の皮付き生栗を用いる。そして皮付き生栗を水洗し、浮き栗（腐った栗や虫喰い栗）や異物を除いた後、乾熱加熱する。乾熱加熱は、石焼釜での石焼、砂煎り、炭焼き、遠赤外線加熱等の方法が挙げられる。
この場合の乾熱加熱条件は、高温短時間で行われることが望ましく、具体的には、１５０〜２５０℃で１５分以内、更に好ましくは５〜１５分行われることが、鬼皮、渋皮が栗果肉から遊離し、剥皮がしやすくなること、また、加熱加工後長期保存した調理栗の変色が防止される点で好適である。
【００１８】
また、その他の乾熱加熱方法としては、熱風ロースト等のような、流体加熱する方法が、鬼皮、渋皮を短時間で完全に取り除くことができ、かつ急速に乾熱加熱されるので、剥皮後、調理栗として保存した時に、変色、風味の劣化がなく特に好適である。すなわち、この方法では、後述するような、予め栗表面に切り目を施して砂煎りするなどの工程が不要で、流体加熱するだけで、鬼皮、渋皮が栗果肉から遊離し、また、栗表面に亀裂が生じ、栗果肉から鬼皮、渋皮を剥離し易くなる。従って、短時間で大量に処理することができ、また、焼き栗の香ばしさも付与することができる。
具体的には、ジェットゾーンシステム（連続式）、ジェットロースト（バッチ式）（共に、荒川製作所製）などの、熱風乾燥やコーヒー豆の焙煎などに用いられる熱風が対流する装置を用いると好適である。
【００１９】
また、流体加熱による乾熱加熱の処理条件としては、装置仕様、処理量によって適宜設定すればよく、熱風の温度は、栗の表面温度が１００〜１１０℃程度になるように、１１０〜１４０℃とすることが望ましい。
例えば、栗に対して上下方向から熱風があたるような熱風乾燥装置（例えば、ジェットゾーンシステム（流動層式）、荒川製作所製）の場合、１２０〜１２５℃の熱風で栗の表面が１０８〜１０９℃となるようにするのが、栗の皮を栗果肉から良好に遊離し、且つ栗の形状を保持する点で最も好適である。また、栗に対して一方向からのみ熱風があたるような熱風乾燥装置（例えば、ジェットゾーンＳＲ−ＢＩＩＩ（バッチ式）、荒川製作所製）の場合には、１３０〜１４０℃の熱風で、栗の表面１０５〜１１０℃程度にすることが好適である。
また、風速は、１２０〜１３０℃、１０〜２０分間加熱する場合、４０〜６０ｍ／ｓが好ましい。
このようにして得られた栗は、この後、人手もしくは機械によって簡単に渋皮ごと剥離することができる。
【００２０】
次に、上記のようにして得られた乾熱加熱処理栗は、乾熱加熱処理に引き続き剥皮処理することが望ましく、具体的には表面温度を４０℃以上、好ましくは６０〜８０℃に保持した状態で剥皮することが、鬼皮、渋皮が欠損することなく完全に栗果肉から遊離し、また、加熱加工後長期保存した調理栗の変色が防止される点で好適である。
【００２１】
また、剥き栗を上記のような方法で得ても、長期保存中にはある程度変色の進行が認められることから、乾熱加熱して剥皮した剥き栗を、引き続き−２０〜−４０℃雰囲気下で６時間以内に中心品温０℃以下となるよう急速凍結すると、剥き栗もしくは剥き栗を加熱加工した調理栗の変色の防止効果が更に高まり、好適である。
急速凍結は、冷凍庫のようなバッチ式、コンベア式の急速冷凍硬化トンネルのような連続式があり、中でも連続式のＩＱＦ方式が短時間で急速凍結できる点で好適である。
【００２２】
次に、皮付きの生栗の剥皮を完全に行うために、皮付き生栗の栗皮に切り込みを刻設した後、乾熱加熱し、栗皮を栗果肉から遊離させる栗の皮遊離方法を行うことが好適である。すなわち、皮付き生栗の栗皮に切り込みを刻設した後、乾熱加熱すると、切り込み部分から栗皮の遊離が栗全周に渡って広がり、栗皮を栗果肉から完全に遊離させることができ、その後軽く手で剥くなどの簡単な短時間処理によって確実に剥皮を行うことができる。
上記切り込みの深さは、０．４〜０．７ｍｍに設定されていることが、栗の皮を確実に遊離させる点、並びに最終の調理栗の外観を損なわず、栗果肉の割れが少ない点で好適である。
また、切り込み長さは、皮付き栗表面の最長径に対し５％以上に設定されていることが、栗の皮遊離を確実に行う点で好適である。
好ましくは、２０％〜３０％に設定されていると、最終の栗調理品表面に切り込み痕が残らず、栗果肉の調理中の破損を防止する点で好適である。
【００２３】
また、上記切り込みを入れる際に、確実に一定の深さで所定の数の切り込みを刻設できるよう、次のような栗皮切り込み装置を用いると更に好適である。
【００２４】
以下、本発明の栗皮切り込み装置の一例について第１図、第２図、第３図、第４図に基づき説明する。
栗皮切り込み装置は、第１図に示すように、載置手段（１）と搬送手段（２）と押圧手段（３）と切断手段（４）と排出手段（５）とを備えている。
【００２５】
栗皮切り込み装置を機構別に詳述する。
＜載置手段＞
載置手段（１）は、装置の上方に位置した、上方に開口部、下方に図示しないストッパーを設けた開口部を有する断面濾斗状の、皮付き生栗（６）を投入する栗供給ホッパー（１１）と、該栗供給ホッパー（１１）の下方の開口部と略同一の位置にあり、栗供給ホッパー（１１）より落下してくる皮付き生栗（６）を載置する栗受けケース（１２）とからなり、該栗受けケース（１２）には、皮付き生栗の一部を露出するための栗受け孔（１３）が複数設けられている。即ち、第２図に示すように、栗受け孔（１３）は貫通孔であり、その径は皮付き生栗（６）の下面の一部を露出し保持しうるよう、皮付き生栗（６）の最短径よりも小さい径に設定されている。また、第２図に示すように、栗受けケース（１２）の厚みRは、皮付き生栗（６）の径よりも小さく設定され、皮付き生栗（６）の下面が栗受け孔（１３）から露出すると共に、上面も栗受けケース（１２）から露出していることが、連続駆動で押圧する場合や、確実に押圧できる点で望ましい。そして第１図に示すように、栗受けケース（１２）の長手方向は搬送方向Ｐの垂直方向に、次に述べる搬送手段（２）により複数配列支持されている。
【００２６】
＜搬送手段＞
第１図に戻り、搬送手段（２）は、上記栗受けケース（１２）を間歇駆動もしくは連続駆動して搬送方向Ｐの下流側へ搬送するためのもので、例えばチェーンコンベアなどの無端帯（２１）と、該無端帯（２１）を駆動する駆動手段（図示せず）とからなる。そして、間歇駆動の場合には、上記栗受けケース（１２）は、該搬送手段（２）により、栗供給ホッパー（１１）の下方の開口部と略同一の位置、及び下記に述べる押圧手段（３）の栗抑え板（３４）と略同一の位置に間歇駆動して、停止する機構となっている。
【００２７】
＜押圧手段＞
押圧手段（３）は、搬送手段（２）によって搬送されてきた栗受けケース（１２）に載置された皮付き生栗（６）を上方から押圧するためのものであって、エアシリンダー駆動手段（例えばアクチュエーター、図示せず）によって降下、上昇するエアシリンダー（３１）と、第２図に示すように、コイルバネ抑え板（３２）とコイルバネ（３３）と栗抑え板（３４）とからなる。コイルバネ（３３）と栗抑え板（３４）は、栗受け孔（１３）に各々対応して個別に設けられており、栗受け孔（１３）内の皮付き生栗（６）が各々異なる載置状態であっても、各々の載置状態に応じて個別に押圧しうるようになっている。そして、上記栗受けケース（１２）が搬送手段（２）によって所定位置に到達すると、間歇駆動の場合等、必要に応じて位置信号等（図示せず）を検知し、あるいは連続駆動の場合は、連続的にてエアシリンダー（３１）がエアシリンダー駆動手段（例えばアクチュエーター、図示せず）によって降下し、コイルバネ抑え板（３２）を所定位置まで押圧してコイルバネ（３３）を介して栗押抑え板（３４）が降下し、皮付き生栗（６）の上面が押圧される機構となっている。
【００２８】
＜切断手段＞
切断手段（４）は、上記押圧手段（３）と同期して作動し、該押圧手段（３）の押圧方向Ｑ下方に設けられ、該押圧手段（３）によって押圧された皮付き生栗（６）の栗受け孔（１３）から露出した部分に当接して栗皮に切り込みを刻設するものであって、切断刃（４１）と該切断刃（４１）を把持する切断刃ガイド（４２）と切断刃駆動手段（４３）とからなり、該切断刃駆動手段（４３）は、切断刃駆動部（４４）と切断刃駆動軸（４５）とからなる。該切断刃（４１）は、第３図に示すように切断刃先端が栗皮の切り込み深さと略同一となるように切断刃ガイド（４２）から露出して把持されている。
【００２９】
＜排出手段＞
排出手段（５）は、上記切断手段（４）の搬送方向Ｐの下流側に設けられ、該切断手段（４）により切り込みを刻設された皮付き生栗（７）を装置外に排出するものであって、栗受けケース（１２）が上記無端帯（２１）によって間歇駆動もしくは連続駆動しながら進行し、無端帯（２１）の搬送方向Ｐの最下流付近で反転することにより、栗受けケース（１２）に載置された切り込みを刻設された皮付き生栗（７）を落下させる、排出シュート（５１）からなる。
【００３０】
なお、上記装置において、切断手段（４）として用いる切断刃（４１）の形状は特に限定されないが、確実に切り込みを入れられる点と、皮付き生栗（６）と切断刃（４１）が適度な圧力で当接し、皮付き生栗（６）と切断刃（４１）とに過剰な負荷や損傷を与えない点で、回転刃を使用することが望ましい。その場合、回転刃の直径は５０〜１００ｍｍが連続的に同じ程度の切り目を刻設できる点で好適である。
【００３１】
また、栗抑え板（３４）等の押圧手段（３）による押圧は、皮付き生栗（６）１個あたりに対して４〜９ｋｇの荷重とすることが、皮付き生栗（６）を安定的に固定でき、皮付き生栗（６）や切断刃（４１）を損傷することなく切り込みを入れられる点で好適である。
【００３２】
また、栗抑え板（３４）は、第３図に示すように皮付き生栗（６）の外周に対応して湾曲していることが、皮付き生栗（６）を確実に押圧しうる点で好適である。
【００３３】
次に、上記装置を用いて生栗の栗皮に切り目を刻設するための方法を工程順に詳述する。
第１図において、（６）は本発明で原料として用いる皮付き生栗であり、切り込みを刻設した後、切り込み入り皮付き生栗（７）となる。
まず、皮付き生栗（６）は、栗供給ホッパー（１１）に適当量投入され、栗供給ホッパー（１１）の下方の図示しないストッパーが開口することにより、栗供給ホッパー（１１）と同じ位置の下方に間歇停止もしくは連続的に到達するよう位置決めされた栗受けケース（１２）内に落下する。栗受けケース（１２）には、栗受け孔（１３）が複数設けられており、栗供給ホッパー（１１）から落下した皮付き生栗（６）が、各栗受け孔（１３）に個別に載置される。
【００３４】
次いで栗受けケース（１２）に載置された皮付き生栗（６）は、無端帯（２１）と無端帯（２１）を駆動する図示しない駆動手段によって栗受けケース（１２）の長手方向と垂直方向の搬送方向Ｐに間歇的もしくは連続的に搬送される。
【００３５】
次に、無端帯（２１）と無端帯（２１）を駆動する図示しない駆動手段により搬送されてきた栗受けケース（１２）に載置された皮付き生栗（６）は、栗受けケース（１２）が搬送手段（２）によって所定位置に到達すると、間歇駆動の場合は、位置信号等（図示せず）を検知し、あるいは連続駆動の場合は連続的に、エアシリンダー（３１）がエアシリンダー駆動手段（例えばアクチュエーター、図示せず）によって降下し、コイルバネ抑え板（３２）を所定位置まで押圧してコイルバネ（３３）を介して栗抑え板（３４）が降下することにより、皮付き生栗（６）の上面が押圧され、皮付き生栗（６）がどのような位置で載置されていても栗受け孔（１３）から確実に皮付き生栗（６）の下面の一部が露出するようになる。
【００３６】
次に、上記栗抑え板（３４）によって栗受け孔（１３）から皮付き生栗（６）が押圧され一部が露出するのと同期して、切断刃駆動部（４４）が駆動し、切断刃駆動軸（４５）を介して連結された切断刃（４１）が回転して、皮付き生栗（６）の露出部に切り込みを刻設する。
【００３７】
次に、切り込みを刻設された切り込み入り皮付き生栗（７）は更に搬送方向Ｐの下流側に設けられた排出シュート（５１）から排出され、図示しない籠等に回収される。
【００３８】
以上詳述したように上記栗皮切り込み装置は、栗が落下しない程度の直径の貫通孔のある栗受け孔を有する栗受けケースに皮付き生栗を入れて、この皮付き生栗を上方から押圧して、皮付き生栗の一部を栗受け孔から確実に露出させ、この皮付き生栗の露出部分に対して、切断刃等で切断するので、切断刃が栗露出部分に一定の深さまでしか入らないので、確実に一定深さの切り込みが行われるようになる。
特に、切断刃等で切断するに際して、切断刃の先端を切り込み深さと略同一となるよう露出して切断刃ガイドで把持した切断刃を用いると、一定の深さまでしか切断刃が栗露出部分に入らないので、より確実に一定深さの切り込みが行われるようになる。
【００３９】
（実施例）
次に、実施例を挙げて具体的に説明する。
《参考例１〜３、比較例１〜２》
中国河北省の皮付き天津生栗（１６０粒／ｋｇ）を麻袋に収容し、０℃の冷蔵庫で保管した。そして、下記フェノール量、糖度になったものを用いて、石焼き釜で焼成（２５０℃、５分）し、剥皮（栗表面温度６０℃）し、中心品温−１０℃となるように冷凍（−３０℃の雰囲気下、６０分）し、中心品温３℃となるように水に浸漬して解凍し、水切りしたもの6粒を密封容器（レトルトパウチ）に窒素置換しながら充填密封し、レトルト殺菌（熱水レトルト、１２１℃３０分）したものを３０℃３ヶ月保存し、栗果肉表面の変色を目視にて確認した。結果を表１に示す。
【００４０】
【表１】

【００４１】
《実施例４〜６、比較例３》
参考例１のフェノール量、糖度になった皮付き天津生栗を用いて、石焼き釜で焼成（２５０℃、５分）し、下記条件で剥皮し、剥皮時の状態を目視にて確認した。次いで、参考例１と同様の条件で、冷凍し、水に浸漬し解凍し、水切りしたもの６粒を密封容器（レトルトパウチ）に窒素置換しながら充填密封し、レトルト殺菌したものを３０℃３ヶ月保存し、栗果肉表面の変色を目視にて確認した。結果を表２に示す。
【００４２】
【表２】

【００４３】
《実施例７〜９、比較例４〜５》
参考例１のフェノール量、糖度になった皮付き天津生栗を用いて、下記条件で石焼き釜で焼成し、剥皮（栗表面温度６０℃）し、剥皮時の状態を目視にて確認した。次いで、参考例１と同様の条件で、冷凍し、水に浸漬し解凍し、水切りしたもの６粒を密封容器（レトルトパウチ）に窒素置換しながら充填密封し、レトルト殺菌したものを３０℃３ヶ月保存し、栗果肉表面の変色を目視にて確認した。結果を表３に示す。
【００４４】
【表３】

【００４５】
《実施例１０〜１２、比較例６〜７》
参考例１のフェノール量、糖度になった皮付き天津生栗を用いて、石焼き釜で焼成（２５０℃、５分）し、剥皮（栗表面温度６０℃）し、下記条件で冷凍し、参考例１と同様の条件で、水に浸漬し解凍し、水切りしたもの６粒を密封容器（レトルトパウチ）に窒素置換しながら充填密封し、レトルト殺菌したものを３０℃３ヶ月保存し、栗果肉表面の変色を目視にて確認した。結果を表４に示す。
【００４６】
【表４】

【００４７】
《実施例１３〜１５、比較例８〜９》
参考例１のフェノール量、糖度になった皮付き天津生栗を用いて、下記条件で切れ目を入れ、石焼き釜で焼成（２５０℃、5分）し、剥皮（栗表面温度６０℃）し、剥皮時の状態を目視にて確認した。次いで、参考例１と同様の条件で、冷凍し、水に浸漬し解凍し、水切りしたもの６粒を密封容器（レトルトパウチ）に窒素置換しながら充填密封し、レトルト殺菌し、栗果肉表面の状態を目視にて確認した。結果を表５に示す。
【００４８】
【表５】

【００４９】
《実施例１６、比較例１０》
参考例１のフェノール量、糖度になった皮付き天津生栗を用いて、第１図に示す栗皮切り込み装置を用いて、切れ目深さ０．６ｍｍを基準に切れ目を入れ（比較例は手で切れ目を入れた）、石焼き釜で焼成（２５０℃、5分）し、剥皮（栗表面温度６０℃）し、剥皮時の状態を目視にて確認した。次いで、参考例１と同様の条件で、冷凍し、水に浸漬し解凍し、水切りしたもの６粒をて密封容器（レトルトパウチ）に窒素置換しながら充填密封し、レトルト殺菌し、栗果肉表面の状態を目視にて確認した。結果を表６に示す。
【００５０】
【表６】

【００５１】
産業上の利用可能性
以上のように、本発明の加熱加工用皮付き生栗は、１〜３℃で６ヶ月以内、もしくは５〜１０℃で４ヶ月以内の保管により、該皮付き生栗の栗果肉中の糖度が１０〜２３°に設定されてなる皮付き生栗を、原料として用いているので、栗の収穫時期、保存状態や品種に係わらず、加熱処理後の長期保存中にも変色のない加熱加工栗を得ることができる。
更に、本発明の剥き栗の製法は、皮付きの生栗を乾熱加熱した後、栗表面温度を４０℃以上に保持した高温状態のままで剥皮するので、鬼皮、渋皮が完全に栗果肉から遊離し、また、加熱処理後長期保存した調理栗の変色が防止される。
更に、本発明の剥き栗の製法では、乾熱加熱を１５０〜２５０℃で１５分以内の高温短時間で行うので、更に鬼皮、渋皮が栗果肉から遊離し、剥皮がしやすくなり、また、加熱処理後長期保存した調理栗の変色が防止される。
【００５２】
また、本発明の剥き栗の製法では、乾熱加熱して剥皮した剥き栗を、引き続き−２０〜−４０℃雰囲気下で６時間以内に中心品温０℃以下となるよう急速凍結するので、変色の防止効果が更に高まる。
更に、本発明の栗の皮遊離方法では、皮付き生栗の栗皮に特定深さの切り込みを刻設した後、乾熱加熱するので、切り込み部分から栗皮の遊離が栗全周に渡って広がり、栗皮を栗果肉から完全に遊離させることができ、その後軽く手で剥くなどの簡単な短時間処理によって確実に剥皮を行うことができ、栗表面に損傷のない剥き栗を得ることができる。
また、本発明の栗皮切り込み装置は、皮付き生栗を、栗が落下しない程度の直径の貫通孔のある栗受け孔を有する栗受けケースに入れて、この皮付き生栗を上方から押圧して、皮付き生栗の一部を栗受け孔から確実に露出させ、この皮付き生栗の露出部分に対して、切断刃等で切断するので、切断刃が栗露出部分に一定の深さまでしか入らないので、確実に一定深さの切り込みが行われるようになる。
特に、切断刃等で切断するに際して、切断刃の先端を切り込み深さと略同一となるよう露出して切断刃ガイドで把持した切断刃を用いると、一定の深さまでしか切断刃が栗露出部分に入らないので、より確実に一定深さの切り込みが行われるようになる。
【図面の簡単な説明】
第１図は、本発明にかかる栗皮切り込み装置の全体を示す斜視図であり、第２図は、本発明にかかる栗皮切り込み装置の押圧手段を示す側面図であり、第３図は、本発明にかかる栗皮切り込み装置の別の態様の押圧手段を示す側面図であり、第４図は、本発明にかかる栗皮切り込み装置の切断手段を示す正面図（ａ）及び側面図（ｂ）である。[0001]
Technical field
  The present invention relates to a raw chestnut with a skin for heat processing, which can prevent discoloration during long-term storage of a heat-processed chestnut that can be eaten as it is, such as a peeled Tianjin sweet chestnut, and a chestnut skin from a raw chestnut with skin A method of making peeled chestnuts that can completely peel and prevent discoloration during storage after peeling, chestnut skin release method that can peel chestnuts completely from skinned raw chestnut flesh, and chestnuts This invention relates to a chestnut skin cutting device for completely releasing the skin of chestnut from the chestnut flesh.
[0002]
Background art
  Traditionally, grilled chestnuts are widely used as foods that can be easily eaten while peeling, such as grilled chestnuts of Japanese chestnuts, Tianjin sweet chestnuts baked with Chinese chestnuts, and grilled chestnuts of Western chestnuts. Recently, in order to make Tianjin sweet chestnuts easy to eat, many products have been released that can be peeled and sealed in a heat-resistant bag, and consumers can open the bag and eat it as is. Has also been proposed. For example, in registered utility model No. 3051612, the raw material Tianjin chestnut with skin is baked in a stone pot, cooled overnight, demon skin and astringent skin are removed, frozen and steamed under pressure, cooled, A chestnut-filled Tianjin sweet chestnut is described in which chestnuts are filled and sealed in a heat-resistant bag together with nitrogen gas and heat sterilized.
  However, the bag peeled Tianjin sweet chestnut obtained by the above method is a product whose chestnut flesh color changes from the initial yellow-brown color to green-black color or browns during long-term storage, impairing the appearance There is a problem that the value decreases.
[0003]
  In addition, Tianjin sweet chestnuts with peel bags have a problem that the degree of flavor and discoloration varies depending on the raw chestnut varieties used as raw materials, storage conditions, harvest time, etc., and stable quality is difficult to obtain.
  Thus, for example, Japanese Patent No. 2516149 discloses a method for producing cooked grits that can be supplied year-round.
  This method increases the sweetness by refrigeration of raw chestnuts with skin for a certain period of time, then transfers them to freezing / frozen storage, takes them out at any time, and cooks them with pressurized moist heat. The thickness can be increased about three times.
  However, although the cooked chestnuts obtained by this method can increase sweetness, they are frozen with the skin and cooked under pressure and heat, so the resulting cooked chestnuts have strong astringent skin and demon skin. There is a problem that it adheres to the flesh and is difficult to peel, and the discoloration substance of the skin part migrates or remains in the chestnut flesh by cooking with heat and moisture, promoting discoloration during storage of cooked chestnuts .
  Furthermore, since wet heat treatment is indispensable in this method, it becomes a chestnut containing a lot of moisture and sugar, and there is also a problem that it is difficult to use for various chestnut cooked products.
[0004]
  Of the types of chestnuts, Tianjin chestnuts are not moist heat, but they are peeled after baking, and compared to European chestnuts and Japanese chestnuts, they are relatively easy to peel. There is a problem that it is difficult to remove the demon skin and astringent skin, and there is a problem that the skin remains when the peeled Tianjin sweet chestnut is used, which deteriorates the flavor and appearance.
  Therefore, as a method for improving chestnut skinning efficiency, for example, there is a skinning method described in JP-A-10-84928. In this method, a chestnut seat is cut and then immersed in an aqueous solution containing an enzyme agent to cause the enzyme to act on the contact portion between the pulp and astringent skin to soften, heat and pressurize in the presence of moisture, It is a method of releasing inside and removing demon skin and astringent skin.
  However, in this method, in order to surely spread the action of the enzyme over the entire circumference of the chestnut skin, a plurality or a wide range of cuts are necessary, so that there is a problem that the chestnut meat is easily broken or the appearance is deteriorated. Further, the peeled chestnut obtained by this method has a flavor peculiar to an enzyme agent, has a watery texture like boiled chestnut or steamed chestnut, and cannot give a fragrance like grilled chestnut.
[0005]
  In addition, if the cuts are cut into the chestnuts manually, the chestnut skins are hard and the work burden on the workers is heavy, and the cuts are not stable and the cuts are too deep. As a result, the appearance quality deteriorates. Thus, it is desirable to automate and stably cut in terms of mass production. As such a method, for example, there is a method described in Japanese Patent Publication No. 3-4191.
  In this method, a plurality of rotary blades are contacted in multiple stages from below to chestnuts accommodated in the cup while traveling a group of cups that are endlessly connected and have openings facing downward, and rotated. This is a method in which the chestnut rotates randomly by the rotational movement of the blade and the forward movement of the traveling conveyor, and a cut is made on the entire surface of the chestnut.
  However, with this method, the cutting depth of the rotating blades differs depending on the size of the chestnuts and the direction of the chestnuts contained in the cup. In some cases, cuts may be made in the cuts, so that there is a variation in the cut state, which leads to a deterioration in the appearance of the cooked chestnuts and leads to defective peeling.
[0006]
  The present invention has been made in view of such circumstances, the first of its purpose is to eat as it is, can be used as various processed cooking chestnuts, browning does not occur when stored for a long time after cooking, It is to provide a raw chestnut with a skin for heat-processed chestnut that can stably obtain a cooked chestnut having the original color and flavor of the chestnut regardless of the variety of the chestnut and the harvest time.
  The second purpose is to provide a method for producing a peeled chestnut that can completely peel the chestnut from the raw chestnut with skin and prevent discoloration during storage after the peeling.
  A third object of the present invention is to provide a chestnut skin releasing method capable of completely peeling off chestnut skin from raw chestnut pulp with skin.
  The fourth purpose is a chestnut skin cutting device for completely releasing chestnut skin from the chestnut flesh, regardless of the chestnut size, shape and fixing direction. It is an object of the present invention to provide a chestnut skin incising device that can stably insert a predetermined number of incisions at a depth.
[0007]
Disclosure of the invention
  The present invention is a raw chestnut with skin for use in heat processing,By storage within 1-3 months at 1-3 ° C, or within 4 months at 5-10 ° C,In the chestnut pulp of the raw chestnut with skinSugarDegree is 10-23 °Will be set toThis is a raw chestnut with a skin for heat processing.
  Moreover, this invention is a manufacturing method of the peeling chestnut characterized by peeling in the state which hold | maintained the chestnut surface temperature to 40 degreeC or more after dry-heated the raw chestnut with a skin.
  In the present invention,By storing it at 1-3 ° C for 6 months or at 5-10 ° C for 4 months,In chestnut pulpSugarDegree is 10-23 °Raw chestnuts with skin that is set toIt is a manufacturing method of the striped chestnut characterized by being.
  Moreover, this invention is a manufacturing method of a stripped chestnut characterized by dry-heat heating being performed within 150 minutes at 150-250 degreeC.
  In addition, the present invention is a method for producing a peeled chestnut characterized in that after peeling, it is frozen in an atmosphere of -20 to -40 ° C within 6 hours so that the core product temperature becomes 0 ° C or lower.
  Further, the present invention provides a chestnut skin characterized by incising a cut in the chestnut of the raw chestnut with skin and then heating the raw chestnut with the cut with dry heat to release the chestnut from the chestnut flesh. The release method.
  Further, in the present invention, when the cut is cut in the chestnut of the raw chestnut with skin, the cut depth is set to 0.4 to 0.7 mm, and the cut length is set to 5% or more of the longest diameter of the chestnut. It is a chestnut skin release method characterized by being made.
  The present invention also relates to a chestnut skin-cutting device for engraving cuts in a chestnut skinned with raw chestnut, wherein the chestnut receiving case is provided with a chestnut receiving hole for exposing part of the skinned raw chestnut. A placing means for placing the raw chestnut with skin on the body, a transport means for transporting the chestnut receiving case on which the raw chestnut with skin is placed by the placing means, and inside the chestnut receiving case transported by the transport means A pressing means for pressing the raw chestnut with skin placed on the skin, and a cutting for making a cut in the chestnut skin in contact with the raw chestnut with skin that is pressed by the pressing means and exposed from the chestnut receiving hole A chestnut skin cutting device comprising: means and a discharging means for discharging the raw chestnut with skin cut by the cutting means.
  Moreover, this invention is a chestnut skin cutting device which is a means by which a pressing means presses the raw chestnut with a skin mounted in the chestnut receiving case individually.
  In the present invention, the pressing means includes an air cylinder, a coil spring restraining plate, a coil spring, and a chestnut restraining plate that are lowered and raised by the air cylinder driving means, and the coil spring and the chestnut restraining plate are disposed in the skin inside the chestnut receiving hole. It is a chestnut skin cutting device provided individually corresponding to the number and position of chestnut receiving holes so that the accompanying chestnuts can be pressed individually.
  In the present invention, the cutting means comprises a cutting blade and a cutting blade guide for gripping the cutting blade, and the cutting blade tip is exposed from the cutting blade guide so as to be substantially the same as the cut depth of the chestnut skin. This is a chestnut skin cutting device that is gripped in this way.
  In addition, the present invention is to cut the cut chestnut skin using the above-described chestnut cutting device, and then dry-heat the raw cut chestnut to release the chestnut from the chestnut flesh. It is a chestnut skin release method characterized by letting.
[0008]
  That is, the present inventors accommodated and sealed the peeled chestnuts in a packaging container, and in the method of heat sterilization such as retort sterilization, when heat processing such as retort sterilization is performed, chestnuts are stored during long-term storage. As the color changes, the appearance deteriorates, and the flavor is not preferable, the method of preventing the deterioration of quality after heat processing was examined. As a result, the color changed depending on the storage conditions of the raw raw chestnut as a raw material. The storage conditions of raw chestnuts with skin were studied.
  as a result,By storing it at 1-3 ° C for 6 months or at 5-10 ° C for 4 months,In chestnut pulpSugarDegree is 10-23 °Will be set toIt has been found that when raw chestnut with skin is used as a raw material, a heat-processed chestnut having no discoloration can be obtained during long-term storage after heat treatment, regardless of the chestnut harvest time and variety.
[0009]
  Furthermore, as a method to completely peel the raw chestnut with skin, by leaving the raw chestnut with skin dry and heated, the demon skin and astringent skin that had been partially released again adhered to the chestnut flesh and peeled off. As a result of examining the standing conditions after dry-heated raw chestnuts with dry heat, the chestnut surface temperature was maintained at 40 ° C or higher after dry-heat heating. It was found that if the skin is peeled in the state, the demon skin and astringent skin are completely released from the chestnut flesh, and discoloration of the cooked chestnut stored for a long time after the heat treatment is prevented.
[0010]
  And if dry heating is performed at 150-250 ° C. for a short time within 15 minutes, demon skin and astringent skin will be released from chestnut flesh, making it easier to peel, and cooking stored for a long time after heat treatment We found that discoloration of chestnut was prevented.
[0011]
  In addition, even if the peeled chestnut is processed as described above, the color change is observed to some extent during long-term storage. As a result of examining the storage conditions of the peeled chestnut, the peeled chestnut peeled off by heating with dry heat Was then rapidly frozen in an atmosphere of −20 to −40 ° C. within 6 hours so that the core product temperature would be 0 ° C. or less, and it was found that discoloration of cooked chestnuts stored for a long time after heat treatment was further prevented.
[0012]
  Furthermore, in order to completely peel the raw chestnut with skin, as a result of examining the release method of chestnut skin from the flesh, after incising the chestnut skinned raw chestnut, The release of chestnuts from the cuts spreads all around the chestnut, allowing the chestnuts to be completely released from the chestnut flesh, and then peeling off by simple short-time treatment such as lightly peeling by hand. I found.
[0013]
  In addition, as a result of examining a device that can engrave a predetermined number of incisions with a certain depth when making the above incisions, in order to expose the raw chestnuts with skin and part of the raw chestnuts with skin The chestnut receiving case with a chestnut-receiving hole is pressed from above, and a portion of the raw chestnut with skin is exposed from the chestnut-receiving hole. As a result, the inventors have found that the cutting can be surely performed by cutting with, and have reached the present invention.
  In particular, when cutting with a cutting blade or the like, if a cutting blade that is exposed so that the tip of the cutting blade is substantially the same as the cutting depth and is gripped by the cutting blade guide is used, the cutting blade can only be exposed to chestnuts to a certain depth. Since it does not enter, it has been found that cutting can be performed more reliably, and the present invention has been achieved.
  In addition, by pressing the raw chestnuts with the skin as a pressing means that can be performed individually for each raw chestnut with skin, it is ensured regardless of the size of each skinned raw chestnut and the direction of entering the chestnut receiving hole. It was found that the raw chestnuts with skin can be pressed to reach the present invention.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
  Next, the present invention will be described in detail.
[0015]
  First, the raw chestnut with a skin as a raw material is not particularly limited in variety and size, and may be appropriately selected from those generally used. Normally, raw chestnuts are extracted from iga and are composed of demon skin, astringent skin, and chestnut flesh in order from the outer layer.
  The present invention is particularly preferably used for grilled chestnuts such as Tianjin sweet chestnuts that are peeled and eaten by the occupant or cooked chestnuts that have been peeled and sterilized in a heat-resistant bag.
[0016]
  Next, raw chestnuts for use in the heat processing of the present inventionSugarA degree of 10 to 23 ° is used.Preferably, the total amount of phenol in chestnut pulp is 1 to 25 mg%.
  That is, if the amount is higher than this condition, discoloration occurs when stored after heat processing. On the other hand, if it is less than this condition, the color tone becomes whitish, and the flavor and texture become poor.
  Total phenol content and sugar content are not necessarily correlated.No.
  The total phenol content and sugar content indicate the average content of the whole chestnut meat from which the skin (demon skin and astringent skin) has been removed.
  The storage conditions for raw chestnuts that fall within this range are:1~ 3 ℃ storageIs 6Within 5 months at 5-10 ° CIs 4Within monthsTheFurthermore, when packaging raw chestnuts with skin, it is desirable to use a package with good water permeability and air permeability. As a package with good water permeability and air permeability, for example, water permeable fibers such as cotton, hemp, non-woven fabric, etc. A plurality of them are listed.
  Among them, the hemp package is preferable in that the desired quality (total phenol content, sugar content) can be obtained for a relatively long period of time even if the storage conditions vary slightly.
[0017]
  Next, the peeled chestnut of the present invention is obtained as follows, for example.
  First, preferably the raw chestnut with the above total phenol amount and sugar content is used. The fresh chestnuts with skin are washed with water, and after removing floating chestnuts (rotted chestnuts and insect-eating chestnuts) and foreign substances, dry heat is applied. Examples of the dry heat heating include stone burning in a stone pot, sand roasting, charcoal burning, and far infrared heating.
  The dry heat heating conditions in this case are desirably performed at a high temperature and in a short time. Specifically, it is performed at 150 to 250 ° C. for 15 minutes or less, more preferably 5 to 15 minutes. It is preferable in that it is released from the pulp and is easy to peel, and the discoloration of the cooked chestnut stored for a long time after heat processing is prevented.
[0018]
  As another dry heat heating method, a fluid heating method such as hot air roast can completely remove the demon skin and astringent skin in a short time and is rapidly heated by dry heat. Later, when stored as cooked chestnuts, there is no discoloration or deterioration of flavor, which is particularly suitable. In other words, this method does not require a process such as cutting and sanding the chestnut surface in advance as described later, and the demon skin and astringent skin are released from the chestnut flesh only by fluid heating. Cracks occur, making it easier to peel off the demon skin and astringent skin from the chestnut flesh. Therefore, it can be processed in a large amount in a short time, and the fragrance of grilled chestnuts can be imparted.
  Specifically, it is preferable to use a device that convects hot air used for hot air drying or roasting coffee beans, such as a jet zone system (continuous type) or jet roast (batch type) (both manufactured by Arakawa Seisakusho). It is.
[0019]
  Moreover, what is necessary is just to set suitably as processing conditions of the dry heat heating by fluid heating according to an apparatus specification and a processing amount, and the temperature of a hot air is 110-140 degreeC so that the surface temperature of a chestnut may be about 100-110 degreeC. Is desirable.
  For example, in the case of a hot air drying apparatus (for example, a jet zone system (fluidized bed type), manufactured by Arakawa Seisakusho Co., Ltd.) in which hot air is applied to the chestnut from above and below, the surface of the chestnut is 108 to 109 with hot air of 120 to 125 ° C. It is most preferable that the temperature is set to 0 ° C. in that the chestnut skin is satisfactorily released from the chestnut flesh and the shape of the chestnut is maintained. In addition, in the case of a hot air drying apparatus (for example, jet zone SR-BIII (batch type), manufactured by Arakawa Seisakusho) where hot air is applied only from one direction to chestnut, the hot air of 130 to 140 ° C. The surface is preferably about 105 to 110 ° C.
  The wind speed is preferably 40 to 60 m / s when heated at 120 to 130 ° C. for 10 to 20 minutes.
  The chestnut thus obtained can then be peeled off together with the astringent skin easily by hand or by machine.
[0020]
  Next, it is desirable that the dry heat-treated chestnut obtained as described above is peeled off following the dry heat heat treatment. Specifically, the surface temperature is maintained at 40 ° C. or higher, preferably 60 to 80 ° C. Peeling in such a state is preferable in that the demon skin and astringent skin are completely free from chestnut flesh, and discoloration of cooked chestnuts stored for a long time after heat processing is prevented.
[0021]
  Further, even if the peeled chestnut is obtained by the above-described method, the progress of discoloration is recognized to some extent during long-term storage. Therefore, the peeled chestnut peeled by heating with dry heat is continuously kept in an atmosphere at -20 to -40 ° C. In the case of rapid freezing so that the core product temperature becomes 0 ° C. or less within 6 hours, the effect of preventing discoloration of peeled chestnuts or cooked chestnuts obtained by heating processed peeled chestnuts is further enhanced.
  The quick freezing includes a batch type such as a freezer and a continuous type such as a conveyor type quick freezing and hardening tunnel, and the continuous IQF method is particularly preferable in that it can be quickly frozen in a short time.
[0022]
  Next, in order to completely peel the raw chestnut with skin, a chestnut skin releasing method in which cuts are cut in the chestnut skin with raw skin and then heated with dry heat to release the chestnut from the chestnut flesh. Is preferably performed. That is, after engraving the chestnut of the raw chestnut with skin, when heated with dry heat, the release of the chestnut from the cut portion spreads over the entire chestnut, and the chestnut can be completely released from the chestnut flesh, After that, it can be reliably peeled by a simple short-time treatment such as lightly peeling by hand.
  The depth of the incision is set to 0.4 to 0.7 mm so that the chestnut skin is surely released, and the appearance of the final cooked chestnut is not impaired, and the crack of the chestnut flesh is small It is suitable.
  In addition, it is preferable that the cut length is set to 5% or more with respect to the longest diameter of the chestnut surface with skin in order to surely release the chestnut skin.
  Preferably, when it is set to 20% to 30%, no cut marks are left on the surface of the final chestnut cooked product, which is preferable in terms of preventing breakage during cooking of chestnut pulp.
[0023]
  Further, it is more preferable to use a chestnut cutting device as described below so that a predetermined number of cuts can be engraved with a certain depth when the above cuts are made.
[0024]
  Hereinafter, an example of the chestnut skin cutting device of the present invention will be described with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.
  As shown in FIG. 1, the chestnut skin cutting device includes a placing means (1), a conveying means (2), a pressing means (3), a cutting means (4), and a discharging means (5).
[0025]
  The chestnut cutting device will be described in detail by mechanism.
<Mounting means>
  Chestnut supply for placing the raw chestnut with skin (6) having a funnel-shaped cross section having an opening on the upper side and an opening provided with a stopper (not shown) located on the upper side, the mounting means (1) Chestnut holder on which the peeled raw chestnut (6) falling from the chestnut supply hopper (11) is placed at substantially the same position as the hopper (11) and the opening below the chestnut supply hopper (11) The chestnut receiving case (12) is provided with a plurality of chestnut receiving holes (13) for exposing a part of the raw chestnut with skin. That is, as shown in FIG. 2, the chestnut receiving hole (13) is a through-hole, and the diameter of the chestnut raw chestnut (6) is such that a part of the bottom surface of the skinned raw chestnut (6) can be exposed and held. The diameter is set smaller than the shortest diameter of 6). Moreover, as shown in FIG. 2, the thickness R of the chestnut receiving case (12) is set to be smaller than the diameter of the raw chestnut with skin (6). It is desirable that it is exposed from 13) and the upper surface is also exposed from the chestnut receiving case (12) in the case of pressing by continuous driving or in that it can be surely pressed. As shown in FIG. 1, the chestnut receiving case (12) is supported in a plurality in the longitudinal direction in the direction perpendicular to the transport direction P by the transport means (2) described below.
[0026]
<Conveying means>
  Returning to FIG. 1, the conveying means (2) is for intermittently driving or continuously driving the chestnut receiving case (12) to convey it downstream in the conveying direction P. For example, an endless belt such as a chain conveyor ( 21) and driving means (not shown) for driving the endless belt (21). In the case of intermittent driving, the chestnut receiving case (12) is moved by the conveying means (2) to approximately the same position as the opening below the chestnut supply hopper (11) and the pressing means (described below). This is a mechanism that intermittently drives and stops at substantially the same position as the chestnut restraining plate (34) of 3).
[0027]
<Pressing means>
  The pressing means (3) is for pressing the peeled raw chestnut (6) placed on the chestnut receiving case (12) conveyed by the conveying means (2) from above, and is driven by an air cylinder. The air cylinder (31) is lowered and raised by means (for example, an actuator, not shown), and as shown in FIG. 2, a coil spring restraining plate (32), a coil spring (33), and a chestnut restraining plate (34). . The coil spring (33) and the chestnut restraining plate (34) are individually provided in correspondence with the chestnut receiving holes (13), and the raw chestnuts with skin (6) in the chestnut receiving holes (13) are different from each other. Even in the mounted state, it can be pressed individually according to each mounted state. When the chestnut receiving case (12) reaches a predetermined position by the conveying means (2), a position signal or the like (not shown) is detected as necessary, such as in the case of intermittent driving, or in the case of continuous driving. The air cylinder (31) is continuously lowered by the air cylinder driving means (for example, an actuator, not shown), and the coil spring restraining plate (32) is pressed to a predetermined position to restrain the chestnut via the coil spring (33). The plate (34) descends, and the upper surface of the peeled raw chestnut (6) is pressed.
[0028]
<Cutting means>
  The cutting means (4) operates in synchronism with the pressing means (3), is provided below the pressing direction Q of the pressing means (3), and is a raw chestnut with skin pressed by the pressing means (3) ( 6) The chestnut skin is cut in contact with a portion exposed from the chestnut receiving hole (13) of 6), and includes a cutting blade (41) and a cutting blade guide (42) for holding the cutting blade (41). ) And a cutting blade driving means (43). The cutting blade driving means (43) includes a cutting blade driving portion (44) and a cutting blade driving shaft (45). As shown in FIG. 3, the cutting blade (41) is held by being exposed from the cutting blade guide (42) so that the tip of the cutting blade is substantially the same as the cut depth of the chestnut.
[0029]
<Discharge means>
  The discharge means (5) is provided downstream of the cutting means (4) in the conveying direction P, and discharges the raw chestnut with skin (7) cut by the cutting means (4) to the outside of the apparatus. The chestnut receiving case (12) advances while being intermittently driven or continuously driven by the endless belt (21), and reverses in the vicinity of the most downstream in the transport direction P of the endless belt (21). It consists of a discharge chute (51) for dropping a peeled raw chestnut (7) engraved with a cut placed on the case (12).
[0030]
  In addition, in the said apparatus, although the shape of the cutting blade (41) used as a cutting | disconnection means (4) is not specifically limited, The point which can be cut reliably and the raw chestnut with a skin (6) and the cutting blade (41) are moderate. It is desirable to use a rotary blade in that it makes contact with an appropriate pressure and does not give an excessive load or damage to the peeled raw chestnut (6) and the cutting blade (41). In that case, the diameter of the rotary blade is preferably 50 to 100 mm in that a cut having the same degree can be continuously engraved.
[0031]
  In addition, the pressing by the pressing means (3) such as the chestnut restraining plate (34) may be applied with a load of 4 to 9 kg per skinned raw chestnut (6). It is suitable in that it can be fixed stably and can be cut without damaging the raw chestnut with skin (6) or the cutting blade (41).
[0032]
  Further, as shown in FIG. 3, the chestnut restraining plate (34) is curved so as to correspond to the outer periphery of the skinned raw chestnut (6), so that the skinned raw chestnut (6) can be surely pressed. This is preferable in terms of points.
[0033]
  Next, a method for engraving cuts in the raw chestnut skin using the above apparatus will be described in detail in the order of steps.
  In FIG. 1, (6) is a raw chestnut with a skin used as a raw material in the present invention, and after making a cut, it becomes a raw chestnut with a cut (7).
  First, an appropriate amount of the raw chestnut with skin (6) is put into the chestnut supply hopper (11), and a stopper (not shown) below the chestnut supply hopper (11) opens, so that the same position as the chestnut supply hopper (11) is opened. Of the chestnut receiving case (12) positioned to stop intermittently or reach continuously. The chestnut receiving case (12) is provided with a plurality of chestnut receiving holes (13), and the raw chestnuts (6) dropped from the chestnut supply hopper (11) are individually provided in each chestnut receiving hole (13). Placed.
[0034]
  Next, the raw chestnut with skin (6) placed on the chestnut receiving case (12) is moved in the longitudinal direction of the chestnut receiving case (12) by a driving means (not shown) for driving the endless belt (21) and the endless belt (21). It is conveyed intermittently or continuously in the vertical conveyance direction P.
[0035]
  Next, the raw chestnut with skin (6) placed on the chestnut receiving case (12) conveyed by the driving means (not shown) for driving the endless belt (21) and the endless belt (21) 12) When the transport means (2) reaches a predetermined position, a position signal or the like (not shown) is detected in the case of intermittent driving, or continuously in the case of continuous driving. It is lowered by a cylinder driving means (for example, an actuator, not shown), presses the coil spring restraining plate (32) to a predetermined position, and the chestnut restraining plate (34) descends via the coil spring (33). The upper surface of the chestnut (6) is pressed and a part of the lower surface of the raw chestnut with skin (6) is surely placed from the chestnut receiving hole (13) regardless of the position of the raw chestnut with skin (6). Will be exposed.
[0036]
  Next, the cutting blade drive unit (44) is driven in synchronism with the chestnut restraining plate (34) being pressed from the chestnut receiving hole (13) and the exposed raw chestnut (6) being partially exposed, The cutting blade (41) connected via the cutting blade drive shaft (45) rotates to cut in the exposed portion of the raw chestnut with skin (6).
[0037]
  Next, the raw chestnuts with cuts (7) provided with cuts are discharged from a discharge chute (51) provided on the downstream side in the transport direction P, and collected by a bag not shown.
[0038]
  As described above in detail, the chestnut skin cutting device puts a raw chestnut with a skin into a chestnut receiving case having a chestnut receiving hole with a through-hole with a diameter that does not drop the chestnut, Press to ensure that a portion of the raw chestnut with skin is exposed from the chestnut-receiving hole, and the exposed portion of the raw chestnut with skin is cut with a cutting blade or the like. Since only the depth is entered, the cutting of a certain depth is surely performed.
  In particular, when cutting with a cutting blade or the like, if a cutting blade that is exposed so that the tip of the cutting blade is substantially the same as the cutting depth and is gripped by the cutting blade guide is used, the cutting blade can only be exposed to chestnuts to a certain depth. Since it does not enter, a certain depth of cut is more reliably performed.
[0039]
(Example)
  Next, an example is given and it demonstrates concretely.
《referenceExamples 1-3, Comparative Examples 1-2 >>
  Tianjin fresh chestnuts with skin from Hebei Province (160 tablets / kg) were stored in a hemp bag and stored in a refrigerator at 0 ° C. And using the following phenol amount and sugar content, calcined in a stone pot (250 ° C, 5 minutes), peeled (chestnut surface temperature 60 ° C), frozen to a core product temperature of -10 ° C (In an atmosphere of -30 ° C for 60 minutes), soak and thaw in water so that the core product temperature is 3 ° C, and then drain and drain the 6 capsules in a sealed container (retort pouch) while filling and sealing. What was sterilized by retort (hot water retort, 121 ° C., 30 minutes) was stored at 30 ° C. for 3 months, and the discoloration of the chestnut flesh surface was visually confirmed. The results are shown in Table 1.
[0040]
[Table 1]

[0041]
<< Examples 4 to 6, Comparative Example 3 >>
referenceUsing the peeled Tianjin fresh chestnut with the amount of phenol and sugar content of Example 1, it was baked in a stone-baked kettle (250 ° C., 5 minutes), peeled under the following conditions, and the state at the time of peeling was confirmed visually. ThenreferenceUnder the same conditions as in Example 1, frozen, soaked in water, thawed, drained, filled 6 capsules in a sealed container (retort pouch) with nitrogen replacement, retort sterilized and stored at 30 ° C for 3 months The discoloration of the chestnut flesh surface was confirmed visually. The results are shown in Table 2.
[0042]
[Table 2]

[0043]
<< Examples 7-9, Comparative Examples 4-5 >>
referenceUsing the peeled Tianjin chestnut with the phenol amount and sugar content of Example 1, it was baked in a stone-baked kettle under the following conditions, peeled (chestnut surface temperature 60 ° C.), and the state at the time of peeling was confirmed visually. ThenreferenceUnder the same conditions as in Example 1, frozen, soaked in water, thawed, drained, filled 6 capsules in a sealed container (retort pouch) with nitrogen replacement, retort sterilized and stored at 30 ° C for 3 months The discoloration of the chestnut flesh surface was confirmed visually. The results are shown in Table 3.
[0044]
[Table 3]

[0045]
<< Examples 10 to 12, Comparative Examples 6 to 7 >>
referenceUsing the peeled Tianjin fresh chestnut with the amount of phenol and sugar content of Example 1, calcined in a stone-baked pot (250 ° C, 5 minutes), peeled (chestnut surface temperature 60 ° C), frozen under the following conditions,referenceUnder the same conditions as in Example 1, 6 capsules immersed in water, thawed and drained were filled and sealed in a sealed container (retort pouch) with nitrogen replacement, sterilized by retort, stored at 30 ° C for 3 months, and chestnut meat The discoloration of the surface was confirmed visually. The results are shown in Table 4.
[0046]
[Table 4]

[0047]
<< Examples 13-15, Comparative Examples 8-9 >>
referenceUsing the peeled Tianjin raw chestnut with the amount of phenol and sugar content of Example 1, cut under the following conditions, baked in a stone-baked pot (250 ° C, 5 minutes), peeled (chestnut surface temperature 60 ° C), The state at the time of peeling was confirmed visually. ThenreferenceFrozen, soaked in water, thawed and drained under the same conditions as in Example 1, filled and sealed in a sealed container (retort pouch) with nitrogen replacement, sterilized by retort, and visually observed on the surface of chestnut flesh Confirmed. The results are shown in Table 5.
[0048]
[Table 5]

[0049]
<< Example 16, Comparative Example 10 >>
referenceUsing the chestnut skinned chestnut with the amount of phenol and sugar content of Example 1 and using the chestnut skin cutting device shown in FIG. The cut was cut), fired in a stone-fired pot (250 ° C., 5 minutes), peeled (chestnut surface temperature 60 ° C.), and the state at the time of peeling was confirmed visually. ThenreferenceUnder the same conditions as in Example 1, frozen, immersed in water, thawed, drained 6 grains, sealed in a sealed container (retort pouch) filled with nitrogen, sterilized by retort, and the chestnut meat surface condition It was confirmed visually. The results are shown in Table 6.
[0050]
[Table 6]

[0051]
Industrial applicability
  As described above, the raw chestnut with heat processing skin of the present invention isBy storing it at 1-3 ° C for 6 months or at 5-10 ° C for 4 months,In chestnut pulpSugarDegree is 10-23 °Will be set toSince raw chestnut with skin is used as a raw material, a heat-processed chestnut that does not change color during long-term storage after heat treatment can be obtained regardless of the chestnut harvest time, storage state, and variety.
  Furthermore, the method for producing the peeled chestnut of the present invention is that the raw chestnut with skin is dry-heated and then peeled off in a high temperature state where the chestnut surface temperature is maintained at 40 ° C. or higher. Discoloration of cooked chestnuts released from the pulp and stored for a long time after heat treatment is prevented.
  Furthermore, in the method for producing peeled chestnuts of the present invention, dry heat heating is performed at 150 to 250 ° C. for a short time at a high temperature within 15 minutes, so that the demon skin and astringent skin are further released from the chestnut flesh, making it easier to peel. Discoloration of cooked chestnuts stored for a long time after heat treatment is prevented.
[0052]
  Moreover, in the manufacturing method of the peeled chestnut of the present invention, the peeled chestnut peeled by dry heat is rapidly frozen so that the core product temperature is 0 ° C. or lower within 6 hours in an atmosphere of −20 to −40 ° C. The effect of preventing discoloration is further enhanced.
  Furthermore, in the chestnut skin releasing method of the present invention, a cut of a specific depth is engraved into the chestnut skin of the raw chestnut with skin, and then dry-heated, so that the release of chestnut skin spreads over the entire chestnut from the cut portion. , Chestnut skin can be completely released from chestnut flesh, and then it can be peeled reliably by simple short-time treatment such as lightly peeling by hand, and peeled chestnuts that are undamaged on the chestnut surface can be obtained .
  Moreover, the chestnut skin cutting device of the present invention puts the raw chestnut with a skin into a chestnut receiving case having a chestnut receiving hole with a through-hole having a diameter that does not drop the chestnut, and presses the raw chestnut with skin from above. Then, a part of the raw chestnut with skin is surely exposed from the chestnut receiving hole, and the exposed part of the raw chestnut with skin is cut with a cutting blade or the like. Since it only enters, it will surely make a certain depth of cut.
  In particular, when cutting with a cutting blade or the like, if a cutting blade that is exposed so that the tip of the cutting blade is substantially the same as the cutting depth and is gripped by the cutting blade guide is used, the cutting blade can only be exposed to chestnuts to a certain depth. Since it does not enter, a certain depth of cut is more reliably performed.
[Brief description of the drawings]
  FIG. 1 is a perspective view showing the whole chestnut skin cutting device according to the present invention, FIG. 2 is a side view showing the pressing means of the chestnut skin cutting device according to the present invention, and FIG. FIG. 4 is a side view showing a pressing means of another embodiment of the chestnut cutting device according to the present invention, and FIG. 4 is a front view (a) and a side view (b) showing the cutting means of the chestnut cutting device according to the present invention. ).

Claims

A chestnut skin-cutting device for engraving cuts in the chestnuts of raw chestnuts with skin, and the chestnuts with skins provided in chestnut-receiving cases provided with chestnut receiving holes for exposing part of the raw chestnuts with skin Placed in the chestnut receiving case transported by the transporting means, the transporting means for transporting the chestnut receiving case on which the raw chestnut with skin is placed by the mounting means A pressing means for pressing the raw chestnut with skin, a cutting means for abutting the raw chestnut pressed by the pressing means and exposed from the chestnut receiving hole, and for cutting a cut in the chestnut skin, and the cutting A chestnut skin cutting device comprising: a discharging means for discharging the raw chestnut with skin cut by means.

Pressing means, chestnuts receives chestnut starting inclusive apparatus according to claim 1, wherein the placed unpeeled raw chestnuts into the case is a means for pressing separately.

The pressing means comprises an air cylinder, a coil spring restraining plate, a coil spring, and a chestnut restraining plate that are lowered and raised by the air cylinder driving means, and the coil spring and chestnut restraining plate individually separate the raw chestnuts in the chestnut receiving hole. The chestnut skin cutting device according to claim 1 , wherein the chestnut skin cutting device is individually provided in correspondence with the number and position of chestnut receiving holes so as to be pressed.

The cutting means comprises a cutting blade and a cutting blade guide for gripping the cutting blade, and the cutting blade tip is exposed and gripped from the cutting blade guide such that the cutting blade tip is substantially the same as the cut depth of the chestnut skin. Item 1. A chestnut skin cutting device according to item 1 .

After slicing the incision into the chestnut of the raw chestnut with skin using the chestnut skin incising device according to claim 1 , the raw chestnut with incision is dry-heated to release the chestnut from the chestnut flesh. A characteristic chestnut skin release method.