JP3996958B2 - Tobacco treatment method for reducing nitrosamine content and product produced thereby - Google Patents

Description

現在では、緑色の、収穫したてのタバコには亜硝酸塩またはTSNAは事実上、全く含まれていないこと、およびこれらの化合物はタバコの保蔵処理および貯蔵の間に生じることが一般的に同意されている。過去10年間に、タバコの保蔵処理の間のTSNAの形成に関連する事象を決定しようと試みる研究がなされ、重要な数個の要因が同定された。これらには、植物の遺伝子型、収穫時の植物の成熟度、保蔵処理条件および微生物の活動が含まれる。
研究により、例えば、特定の空気保蔵処理される系統に関しては収穫後2-3週間、フルー保蔵処理される品種では収穫後およそ1週間ほどなど、亜硝酸塩およびTSNAは、黄色化の終わりよりも後に始まり、葉が完全に茶色に変わるときに終わる時間の間の空気保蔵処理の際に蓄積することが示された。これは、その間に水分の喪失および細胞間隙への細胞内容の漏出による細胞の完全性の喪失が起こる時間である。それゆえ、空気保蔵処理の間の時間に、細胞が崩壊し、微生物が利用可能な栄養物を作る短い時間帯がある。Weirnikらは、硝酸塩の異化還元の結果、次は亜硝酸塩が実質的に蓄積し、それゆえTSNAの形成を可能にし得ることを示唆した。
Weirnikらに引用されているように、生育および保蔵処理の間のタバコ葉に対する、および保蔵処理されたタバコに対する、微生物フローラの影響についての発表された報告が少しはある。しかし、保蔵処理の間の硝酸塩の生成における微生物の亜硝酸塩還元酵素の関与は仮定されている。黄色期の後に細胞構造が崩れ去り、侵入してくる微生物にとって栄養物が利用しやすくされる時に、有利な条件下、すなわち高い湿度、至適な温度および無酸素で、これらが亜硝酸塩を作り出し得る。水の活性が依然として十分に高く、細胞構造が崩壊した時間に、通常は幾分短い“時間帯”がある。
本発明に従い、収穫された葉を本明細書中で記載する条件下でマイクロ波放射にかけることにより、タバコ中のTSNAの形成は実質的に阻止されるまたは抑えられる。好ましい一態様においては、タバコ葉を黄色化の開始と細胞の完全性の実質的な喪失の間の時点でマイクロ波エネルギーにさらす。最適な結果のためには、組合わさったまたは積み重なった葉とは対称的に、収穫した葉を一枚の葉としてマイクロ波界を通過させるのが好ましい。この方法で葉を処理すると、既知の発癌物質であるNNNおよびNNKを含むタバコ特異的ニトロソアミンの形成を完全にまたは実質的に阻止することが確定されている。
本発明の好ましい態様に従い、ヒトの消費に適し、通常通りに保蔵処理されたタバコよりも少なくとも1つのタバコ特異的ニトロソアミンの含量が低いような、緑色でないかつ/または黄色のタバコ製品を得ることができる。緑色のまたは切りたてのタバコは、上に記したように一般的にはヒトの消費に適していないが、本明細書中で使用されている場合に“緑色でない”とは、タバコが少なくともクロロフィルの大部分を失ったことを意味し、部分的に黄色の葉、完全に黄色の葉およびところどころに茶色に変わり始めた葉が制限無しに含まれる。好ましい態様においては、緑色でないタバコ製品は、TSNA（NNN、NNK、NABおよびNAT）含量が.2μg/g以下、より好ましくは約.15μg/g以下、さらにより好ましくは約.1μg/g以下であり、NNN含量が約.15μg/g以下、より好ましくは約.10μg/g以下、さらにより好ましくは.05μg/g以下であり、NNK含量が約.002μg/g以下、より好ましくは約.001μg/g以下、さらにより好ましくは.0005μg/g以下である。上に記したように、タバコ中のTSNA形成に影響し得る多数の要因を考慮すると、当業者はこれらの数字が絶対的なものではなく、むしろ好ましい範囲であるということを理解するだろう。
本発明は、ヒトの消費に適し、かつ通常通りに保蔵処理されたタバコよりも少なくとも1つのタバコ特異的ニトロソアミンの含量が低いような、乾燥された黄色のタバコを含むタバコ製品をも目指している。好ましい態様においては、黄色のタバコ製品はTSNA（NNN、NNK、NABおよびNAT）含量、NNN含量、およびNNK含量は上の好ましい範囲内である。
他の態様においては、緑色でないまたは黄色のタバコ製品には、ヒトの消費に適し、かつTSNA（NNN、NNK、NABおよびNAT）含量が、その製品が製造される収穫したての緑色のタバコ収穫物中のそのようなTSNAの含量の重量で約25%以内である、緑色でないまたは黄色のタバコが含まれる。緑色でないまたは黄色のタバコ製品が、TSNA含量がその製品が製造される収穫したてのタバコ収穫物中のそのようなTSNA含量に対して、重量で約10%以内であるのはより好ましく、より好ましくは重量で約5%以内であり、最も好ましくは本質的に近い（例えば、重量で数パーセントまでの量以内）。例えば、本発明により、TSNA含量が上に記載した量に関する範囲内にあるタバコ製品を製造することが可能であるのに対し、同じ収穫物から通常通りに保蔵処理されたタバコは、切りたてのタバコ中の何倍もの量のTSNAを生じるだろう。本発明は、切りたての緑色のタバコ中に見出される低量のニトロソアミンに効果的にとどめ得る。緑色でないまたは黄色のタバコ製品に、ヒトの消費に適し、かつNNN、NNK、NABおよびNATから選択される少なくとも1つのTSNAの含量が、その製品が製造される収穫したての緑色のタバコ収穫物中の対応するTSNAまたはTSNAsの含量に対して、重量で約25%以内、好ましくは重量で約10%以内、より好ましくは重量で約5%以内、最も好ましくは本質的に近い（例えば、重量で数パーセントまでの量以内）ような、緑色でないまたは黄色のタバコが含まれるのも好ましい。言い換えれば、切りたての緑色のタバコ中のNNNの量と比較して、本発明のタバコ中の例えばNNNなどの含量は上の範囲内に減少する、あるいは、切りたての緑色のタバコ中のNNN+NNKの量と比較して、本発明のタバコ中のNNN+NNKなどの含量は上の範囲内に減少する、など。これらの比較をする際に、切りたての緑色のタバコを、好ましくは収穫後約24時間以内にTSNA含量に関して解析する。
本発明のさらに別の態様においては、緑色でないまたは黄色のタバコ製品には、ヒトの消費に適し、かつTSNA（NNN、NNK、NABおよびNAT）含量が、本発明の製品として同じタバコ収穫物から作られる同じ種類のタバコ製品中のそのようなTSNA含量よりも、重量で少なくとも約75%、好ましくは重量で少なくとも約90%、より好ましくは重量で少なくとも約95%、最も好ましくは重量で約99%低いような、緑色でないまたは黄色のタバコが含まれるが、それはTSNA含量を減少させるために設計された、マイクロ波放射または他の技術のない時に保蔵処理されたものである。緑色でないまたは黄色のタバコ製品に、ヒトの消費に適し、かつNNN、NNK、NABおよびNATから選択される少なくとも1つのTSNAの含量が、本発明の製品として同じタバコ収穫物から作られる同じ種類のタバコ製品中の対応するTSNAまたはTSNAsの含量よりも、重量で少なくとも約75%、好ましくは重量で少なくとも約90%、より好ましくは重量で少なくとも約95%、最も好ましくは重量で少なくとも99%低いような、緑色でないまたは黄色のタバコが含まれるが、それはマイクロ波放射または他の技術のない時に保蔵処理されたものである、というのも好ましい。これらの態様においては、TSNAの重量%の比較は、例えば、本発明に従い乾燥された黄色タバコを用いて製造された紙巻きタバコなどを利用し、乾燥された黄色のタバコが製造されたのと同じ収穫物由来のタバコから製造されたが、それをマイクロ波放射にかけることのない通常の手段により保蔵処理した紙巻きタバコを利用することによりなされ得る。
タバコ葉をマイクロ波放射にかける過程が好ましく行われるような黄色化の段階は、以下の方法のうちのいかなる1つによっても広く定義され得る。すなわち、(a)緑色が実質的に黄色がかった色にとって代わられたときに、葉の色を調べることによる；(b)クロロフィルの糖への転換の割合を測定することによる；(c)典型的には黄色期の終わりと同時に起こる、亜硝酸塩形成またはニトロソアミン生成のいずれかの開始を観測することによる；あるいは(d)例えば、葉が重量で約40から約70パーセントの水分含量である時などに、葉の水分含量を測定することによる。マイクロ波放射を緑色のタバコに適用する場合には、ニトロソアミン形成の抑制または阻止は観察されない。しかし、マイクロ波エネルギーが黄色化の開始より後で、細胞の完全性の喪失または葉におけるTSNAの実質的な蓄積より前に適用される場合は、観察されたニトロソアミンの量の減少または形成の阻止は、以下に議論するデータにより示される通り、劇的かつ意外である。
収穫されたタバコを黄色期の間にマイクロ波放射にかける至適時間は、品種の違い、環境変化などを含む多数の要因によって変わる。従って、黄色化の開始（例えば葉の緑色の大半の喪失などによって定義される）で始まり、葉が細胞の完全性を実質的に失う時点（茶色に変化する時）までの時間枠内で、当業者はあらゆる特定のタバコの品種に関してマイクロ波処理を行う至適時間を決定し得た。例えば、ある遺伝子型に関しては、有意なTSNAの蓄積が始まる、特定の保蔵処理サイクル中の相対的な時間を同定する、あるいは細胞の完全性の喪失が起こる遷移期を同定するために、本明細書中に記載の手順により試料葉を分析し、亜硝酸塩またはTSNAの含量のいずれかを測定し得た。有意なTSNA蓄積より前に葉をマイクロ波放射にかけることが、本発明の方法の最も好ましい形である一方、本発明の原理は、TSNAの形成の過程にある、あるいは有意な量のTSNAをすでに蓄積したタバコ葉に対しても適用し得る。マイクロ波放射をこの遅い段階に行う場合、TSNAのさらなる形成を効果的に抑え得る。しかし、葉がひとたび完全に保蔵処理されたなら、TSNA量は本質的に安定し、マイクロ波照射の適用は以下に記載する再水化条件下を除き、TSNA含量を減少させることには効果がない。
本発明に従いマイクロ波放射にかける際に、タバコ葉は一般的に水分含量が減少している、すなわち、重量で焼く10%以下でありしばしばおよそ5%である。もし望むならば、紙巻きタバコなどのタバコ製品に製造される前に、茶色の、保蔵処理されたタバコについて、典型的な水分範囲（例えば、バージニアフルーについては約11-15%）にまで戻って葉を再水化し得る。
本発明は、フルーまたは明るい品種、バーリー品種、暗い品種、東洋/トルコの品種などを含むすべての系統に対して適用可能である。本明細書中に示す指針の範囲内で、当業者は本発明の目的および利点を達成するために、マイクロ波の過程を行うための保蔵処理サイクル中の最も効果的な時間を決定し得た。
この過程の好ましい観点には、好ましくは茎を含むタバコ葉をマイクロ波放射にかける前に、マイクロ波単位によるより均一な乾燥を確実にするために、葉を物理的に圧搾してそれから過剰の水分をしぼり出す段階が含まれる。この段階は、マイクロ波空洞に入れる前に、適切に間隔をあけて回転する一対の円筒形のローラーに葉を通すことにより、都合よく行うことができる。そのような圧搾過程は、茎、より少ない程度で主脈およびより大きい葉脈から水分をしぼり出すのを助け、よりよくかつより均一に乾燥された製品へと導くだろう。ローラーは硬ゴム、プラスチックまたはスチールから作られ、あらゆる望みの長さであることが可能であり、好ましくは約八分の一から約四分の一インチ間隔が離れているが、その距離は、好ましくは一枚の葉の厚さに適応するように選択され、変わり得る。ローラーは適切に選択されたモーターにより動かされるベルトまたは鎖であり得る。当業者には明らかであるように、回転するローターの他に、もし望むならば他の種類の圧搾または圧縮手段を用いて同じ結果を達成し得た。
上に記述した葉を圧搾する好ましい態様は、葉柄を切除する必要がなく、そしてマイクロウェーブ処理時間を減少できる為に、行われるべき更に高速での生産を可能にする。この態様は、典型的に混合物の一部として少量のタバコの葉柄を含んでいる、紙巻タバコに使用する予定のタバコの葉に対して、特に利益がある。又、葉柄が、葉から除去されそして廃棄されるような場合の適用には、所望により、圧搾工程を省略することもできる。
もう一つの好ましい態様において、葉を圧搾するか又は葉柄を切除する代わりに、マイクロウェーブ処理に先立ち、葉を水蒸気処理に掛けることができる。圧搾工程と同様に、葉柄を含む全体の葉の水蒸気処理は、葉柄及び太い葉脈中の水分を更に均一に分布し、そのためにマイクロウェーブ処理に於いて全体の葉の更に均質な乾燥が得られることが明らかになった。結果として、この特別な技術を採用した場合、葉柄を含んだ全体の葉を、タバコ産物に使用することができる。詳細は当業者にとって明白かもしれないが、葉を適当な水蒸気処理容器内に、葉が僅かに軟らかくなりそして曲げやすくなるに充分な時間、一般的に約３０秒から約５分の間、置いた場合に、好結果が得られた。
本発明の原理は、又、再浸漬した、褐色の又は既に処理されたタバコに対しても適用できる。このような場合、再浸漬した褐色タバコをマイクロウェーブ放射に当てた場合に、重要なそして予期しないＴＳＮＡｓの量の、特にＮＮＮ及びＮＮＫの、減少が認められるが、この結果は、本発明を、未処理の黄色タバコに、実質的な量のＴＳＮＡｓ又は亜硝酸塩が葉に蓄積する時より前に適用した場合ほど目覚ましくはない。それでもなお、葉を効果的に浸漬するに充分な水の噴霧によるような、処理済の葉への水分の添加、続いて再浸漬した葉をマイクロウェーブ処理することは、以下の実施例で明らかにするようにＴＳＮＡｓの含有量を減少する。
上に記載したように、処理済の又は褐色のタバコを処理する場合、マイクロウェーブ処理だけではニトロソアミンの含有量に、僅かな影響しかない。然しながら、処理済タバコをマイクロウェーブ放射に当てる前に、それを再浸漬することは、ニトロソアミンを減少するマイクロウェーブエネルギーの行為を促進することが測定された。一つの好ましい態様に於いて、通常は少なくとも約１０重量％、最大は吸収能力までの、適当な量の水を、葉に直接加えることにより、処理済タバコ産物を再浸漬する。本明細書に未処理タバコについて記載したと同じ方法により、再浸漬した葉を、マイクロウェーブ放射に暴露することにより、ニトロソアミン含有量は、以下に示すように減少する。葉は、いかなる適当な方法で濡らすことができる。もし処理済タバコが、再構成した“薄板状”タバコのような、葉以外の形態の場合、これも同様に例えば１０−７０重量％の水で再浸漬でき、そして次いでマイクロウェーブ処理できる。適当なマイクロウェーブの条件は、葉の再浸漬の度合いにより選択できるが、しかし典型的には、黄色タバコのマイクロウェーブ処理について上に記載した変数の範囲に含まれる。
本発明によれば、再浸漬した褐色タバコのマイクロウェーブ処理は、個別に又は集合的に測定した、ＴＳＮＡ（ＮＮＮ、ＮＮＫ、ＮＡＢ及びＮＡＴ）含有量を、再浸漬以前の処理済褐色タバコに含まれているＴＳＮＡの量から、好ましくは少なくとも約２５重量％、より好ましくは少なくとも約３５重量％そして更に好ましくは少なくとも約５０重量％、減少することができる。
本明細書において使用される“マイクロウェーブ放射”の用語は、マイクロウェーブ領域として典型的に特徴づけられる周波数及び波長を持つ、マイクロウェーブの形態をとる電磁エネルギーを指す。“マイクロウェーブ”の用語は、遠赤外線領域及び通常の無線周波数帯との間にある電磁波帯の部分を一般的に指す。マイクロウェーブの範囲は、波長約１ミリメートルで周波数約３００，０００ＭＨｚから波長３０センチメートルで約１，０００ＭＨｚより僅かに低い周波数まで広がる。本発明は、典型的にはこの周波数域の低域のマイクロウェーブの、好ましくは高電力の応用を使用する。この好ましい周波数域において、マイクロウェーブによる加熱と赤外線（例えば調理）のような古典的加熱方法の間には基本的な相違がある：より大きな貫入により、マイクロウェーブは一般的に数センチメートルの深さまで急速に加熱するが、一方赤外線による加熱は多分に表面的である。米国に於いて調理用電子レンジのような、市販のマイクロウェーブ器具は、それぞれ約９１５ＭＨｚ及び２４５０ＭＨｚの標準周波数で入手可能である。これらの周波数は、標準の工業用周波帯である。ヨーロッパにおいては、２４５０及び８９６ＭＨｚのマイクロウェーブ周波数が通常使用される。然しながら、正確に計算した条件下では、他の周波数そして波長のマイクロウェーブが、本発明の目的そして利益を達成するのに有用であろう。
マイクロウェーブエネルギーは、所望する適用によって、種々の電力水準で発生することができる。６００−１０００ワットの電力水準の通常の調理用マイクロウェーブ器具（通常約８００ワット）の、マイクロウェーブは、典型的にはマグネトロンで発生されるが、しかし商業用装置は、通常約１キロワットのモジュール発生源の付加により、数百キロワットの電力発生まで可能である。マグネトロンは、適当な高周波数のパルス波又は連続波を、発生することができる。
適用器具（或いはオーブン）は、マイクロウェーブ電力発生器及び加熱される素材間の必要な結合手段である。本発明の目的のためには、タバコ作物の部分を効果的に放射線に当てることが可能なように適合されている限りは、いかなる所望の適用器具も使用できる。適用器具は、電力伝達を最適化するためにマイクロウェーブ発生器と適合していなければならず、そして外部へのエネルギーの漏洩を避けなければならない。必要ならば、波長の数倍より大きい寸法にできる、多モード空間（ｃａｖｉｔｉｅｓ）（マイクロウェーブオーブン）が、大型の試料に対しては有用である。葉の内部の均一な加熱を確実にするために、適用器具に、モード撹拌器（電界分布を連続的に変更する金属製の可動器具）及びベルトコンベヤーのような可動平面を装備できる。最良の結果は、束ねた又は積み重ねた葉ではなく、葉一枚の厚みでマイクロウェーブ放射に暴露することにより得られた。
本発明の好ましい態様において、マイクロウェーブの条件は、約９００ＭＨｚから約２５００ＭＨｚのマイクロウェーブ周波数、更に好ましくは約９１５ＭＨｚ及び約２４５０ＭＨｚ、約６００ワットから３００キロワットまでの電力水準、更に好ましくは調理用適用器具に対しては、約６００ワットから約１０００ワット、そして商業用適用多モード器具に対しては、約２から約７５キロワット、更に好ましくは約５から約５０キロワット、を含む。加熱時間は、一般的に少なくとも約１秒間、更に一般的には約１０秒間から約５分間までの範囲である。約８００−１０００ワットの電力水準に於いて、束ねた又は積み重ねた葉ではなく一枚厚みの葉を処理する場合、加熱時間は好ましくは約１分間から２．５分間である。例えば、２−７５キロワットの範囲の高電力水準を使用する、商業規模の適用器具に対する加熱時間は、再び束ねた又は積み重ねた葉ではなく一枚厚みの葉の場合、約５秒間から約６０秒間までの範囲で、そして一般的には５０キロワットならば１０−３０秒間の範囲と短いであろう。もちろん、当業者は、最適なマイクロウェーブ電界密度は、いかなる適用器具に対しても、空間（ｃａｖｉｔｙ）の容積、使用する電力水準、及び葉の中の水分量に基づいて決定できることを、理解するであろう。一般的に言って、より高い電力水準を使用すれば、その間葉をマイクロウェーブ放射に当てる、必要な時間はより短いであろう。
然しながら、上に記載した条件は、絶対的なものではなくそして本発明の説明を与えるものであり、当業者は、適当なマイクロウェーブ条件を、決定することができるであろう。マイクロウェーブ放射は、焦がすことなく、人間の消費に適当なように、好ましくは葉又はその一部に、葉を効果的に乾燥するに充分な時間適用する。マイクロウェーブ放射を、葉又はその一部に、水分含有量を約２０重量％、更に好ましくは１０重量％以下に減少するに充分な時間及び電力水準で、適用するのが好ましい。
さて図３には、商業規模のマイクロウェーブ適用器具の態様を、部分透視図で示してある。特に、移動トラック車枠２（図示されていないが、前端は図の右側）、内部に一枚壁構造（３００３Ｈ１４アルミニウムから適当に構築できる）の、それぞれの空間の概略寸法が、長さ約４．８メートル（１６’）ｘ幅約２．１メートル（８４”）ｘ高さ約１．２メートル（４８”）の、４個のモジュール式オーブン空間を含むコンベヤー化された、マイクロウェーブオーブン３を含む、マイクロドライ（Ｍｉｃｒｏｄｒｙ）３００ｋＷマイクロウェーブタバコ乾燥システム１、を示す。各々の空間は各々の側に２個ずつの４個の出入り扉が備えてある。扉は、マイクロウェーブエネルギーへの偶発的な暴露を防ぐため二重のインターロックにしてある。
図３には、葉４から葉柄を除去するための複数（例えば１２個）の回転刃自動切除機構５が示してある。切除刃は、約８．６センチメートル（３．４インチ）幅の、人力で供給される葉の中心部に下りている直線の平板であっても良い。運転員の手の挿入を防ぐため、所望により、適当な防護設備を設置できる。図３には葉柄切除機構が示されているが、しかし上に記載したように本発明の他の態様によれば、全ての葉を使用することができる。従って、切除機構の代わりに、装置に水蒸気処理容器又は葉から水分を圧搾する一対のローラーを採用できる。
図３に戻って、葉柄切除操作後、切断された葉６は、ベルトコンベヤー７によって、４個の空間を収容する主マイクロウェーブオーブン３に運搬される。一つの態様においては、システムは約２４メートル（約７８フィート）の長さのオーブンを有する。オーブンの導入部及び内部に於いて、コンベヤー系は、切断された葉柄が、一対のベルトの間を抜けそしてベルトの下に設置されたホッパー（図示されていない）に落ちるように設定された、別の複数の、例えば６本の、変速ポリプロピレン製ベルトで構成できる。ベルトは、次いで切断されたタバコの葉を、マイクロウェーブエネルギーを含むように設計された各々の空間に一個ずつ設置された二個のトラップの一個を通って、そして次いで、上記の本発明の原理に従って各々の葉がマイクロウェーブ処理に掛けられる、選択された空間に、運搬するであろう。マイクロウェーブ処理後、コンベヤーは、葉を空間出口を通り、オーブン出口トラップを通りそして、次にそこで葉を更なる工程に持ち出す適当な容器に運搬される、オーブンの外へ運搬する。
空間及びオーブンから水分を含む空気を除去するために、空気再循環を行う適当な送風機を含む排気系を、システムに含めることができる（図３に於いて、代表的に一個を部材８として標識した水分排気通気孔参照）。又、所望により、オーブンの内部を、葉をコンベヤーで運搬する間、マイクロウェーブ空間の外側のオーブンの内部を、好ましい一定の温度、例えば、約７１−８２℃（１６０−１８０°Ｆ）、に保つように、適当な間隔で設置された循環空気の対流式加熱源により、温度制御できる。図３に示すような現場で使用する移動式システムの場合、必要電力は一対の通常のジーゼル動力発電機９、１０により供給できる。もちろん、マイクロウェーブ乾燥システムは、所望により、通常の電源から電力を得て、固定した場所でも又稼動できる。
図３のオーブン３内の四個の空間のそれぞれは、対応するマイクロドライＩＶ−７５型マイクロウェーブ電源からマイクロウェーブエネルギーを受ける。マイクロウェーブエネルギーは、分割器を経由し、各々の空間の頂部に設置された二個の引き込み口からそれぞれの空間に入る。モード撹拌器が、マイクロウェーブエネルギーの分布を補助する為に各々の空間の引き込み口の下に設置されている。各々のマイクロウェーブ電源装置は、７５ｋＷのマグネトロンを稼動するに必要な構成部品を収容する、完全にそれだけで完備した小室（ｃａｂｉｎｅｔ）である。マイクロウェーブ電源の制御は小室に設置されている。装置は、工業的環境で、無人連続運転できるように設計されている。各々のマイクロウェーブ電力発生器は、各々の空間の傍に、又は離れた所に設置しても良い。然しながら、約１５ｍ（５０’）の距離で、伝達線の損失は約２％であろう。各々の電力発生器は、工業用運転のために、調節可能なマイクロウェーブエネルギーを供給する。出力電力は、ＦＣＣの割当てた９１５ＭＨｚの周波数で、０から約７５ｋＷまで調節でき、そして制御盤の制御つまみによる手動調節、又はプロセス制御器からの４−２０ミリアンペアの制御信号による遠隔制御による、ソリッドステート制御回路により、制御される。回路上は電力出力を０から制御するが、しかし周波数幅は、約５ｋＷ以下の水準で幅広くなる。各々の空間の電力発生器は、基本的には自動及び手動運転のために設計された回路機能により操作され保護される、工業用マグネトロンを作動する直流電力供給である。発生器の電気的な機能は小室の扉に設置された、制御盤の計器で監視される。測定は、陽極電流、陽極電圧、出力電力、フィラメント電流、電磁電流及びリフレクト（ｒｅｆｌｅｃｔｅｄ）電力である。電気−機械的インターロック機能の作動は、制御盤上の規定されたランプにより監視される。各々のマイクロウェーブ電力発生器用の小室は、構成部品への最大の接近が可能なように、幅一杯の扉を有する。作り付けの電磁波防御遮蔽容器内に、マグネトロン及び関連するマイクロウェーブ構成部品が、収容されている。扉によって、マグネトロン及び電磁石の設置ができる。システムは、小室の内部に設置された、高リフレクト電力条件時にマグネトロンを保護する隔離物として機能する、循環器と水の積荷を含んでいる。マイクロウェーブ電力発生器は、熱を発生する構成部品を冷却するために、強制空気及び水の両者を使用する。マグネトロン及び電磁石は、閉回路の脱ミネラル水系による水冷却である。別個の水源及び熱交換器を、この回路の水の冷却に使用できる。別個の水源は、又小室内の空気熱交換器にも水を流し、小室内の空気を冷却する。高圧遠心送風機が、マグネトロン出力窓及び陰極構造物の冷却を行う。水及び小室温度は、制御電力鎖内でインターロックされている。本明細書のシステムのマイクロウェーブ発生器の典型的な参考資料は、以下の通りである：
入力電力 ９５ＫＶＡ、４４０−４８０ＶＡＣ、３相、６０Ｈｚ
出力電力 ９１５±１０ＭＨｚで７５ｋＷ
マグネトロン管 ＣＴＬ、ＣＷＭ ７５ Ｉ
典型的なマグネトロン作動の参考資料は以下の通りである：
ＡＣフィラメント電圧 １１．４Ｖ
フィラメント電流 ８５Ａ
ＤＣ陽極電圧 １７ＫＶ
陽極電流 ５．０Ａ
ＤＣ電磁石電流 ４．３Ａ
効率 ８０％
更に、典型的なマイクロウェーブ発生器は、炭素鋼の容器を採用できそして小室頂部の適当な場所に出力結合部（ＷＲ９７５ウェーブガイド）を有している。
処理量試験に於いて、一般的に上に記載したように設計されたマイクロウェーブタバコ乾燥システムは、葉の水分含有量の８０％以上を除去することに効果的であった。特に一つの計測された試料に於いて、８５％の仮定した初期水分含有率及び１５％の固形物含有率の葉約６．８ｋｇ（１５ポンド）を、葉一枚の厚みで、時間当り約８２ｋｇ（１８０ポンド）の速度で、マイクロウェーブ空間を通した。葉の重量を、空間出口の後で測定した。最終重量は約２．１ｋｇ（４．６ポンド）、或いは初期重量の３１％であった。従って、初期の仮定した水含有量に基づけば、葉の中に水は約１．０７ｋｇ（２．３５ポンド）残っており、これは初期の水含有量の１８．５％に相当する。
図２で開示したように、本発明による黄色タバコのマイクロウェーブ処理は、好ましくは乾燥した黄金色のタバコ産物になる。本明細書に提示するデータは、そのようないぶさない形で乾燥したタバコが、標準的に処理されたタバコと違い、劇的に減少した発ガン性のニトロソアミン、特にＮＮＮ及びＮＮＫを、含有していることを立証する。
集中した形態（即ち、可視光線域で太陽光又は電気の光への一般的な暴露から識別できるように集中した）の、上に記載したマイクロウェーブ領域より高い周波数及び短い波長を持つ電磁波の放射を、そのようなエネルギー形態で、マイクロウェーブ態様について上に記載したような、収穫後の概略同じ時間枠内で、タバコを処理することにより、本発明の基本的な目的−タバコ産物のＴＳＮＡｓの減少又は実質的な除去、を達成することに、使用できることがわかった。言い換えると、マイクロウェーブ処理について、上に記載したと同様の一般的でそして好ましい技術及び原理は、そのような別のエネルギー源を使用する場合にも、適用できる；例えば、タバコを収穫後の概略同じ時間枠にそのような放射線で処理し、放射に先立ち、葉を葉柄除去でき、ローラー間で圧搾し又は水蒸気処理し、等である。
然しながら、そのような別のエネルギー源は、ＴＳＮＡｓを、有意にそして好ましく減少し、又は実質的に除去し、又は形成を阻害することには決着がついたが、今日まで試験された他のどの態様も、葉を乾燥することにおいて、詳細に記載したマイクロウェーブ技術のように、効果的でない。従って、そのような別のエネルギー源を使用する場合、照射したタバコの葉を、処理過程を完了する為に、照射工程を、引き続いてのオーブン乾燥又は回転乾燥工程と組合わせた、更なる工程に掛けることが好ましいかもしれない。
特に、通常の電磁波帯内のマイクロウェーブ領域より高い周波数を持つ、いかなる電磁波放射源、及びエレクトロンビームのような加速粒子ビームは、タバコが未処理でそして減少されるべき量のＴＳＮＡｓ又は阻止されるべきその形成、を有する、影響を受けやすい状態にある場合に、ＴＳＮＡｓを有意に減少し、実質的に除去し及び／又は形成を阻害する効果をもたらすと信じられている。マイクロウェーブが１０¹¹Ｈｚそして３ｘ１０^-3メートルの波長を持つ電磁波放射の形態を含むと一般的に定義されている、電磁波帯内のスケール上で、そのようなエネルギー源は、限定的ではなく、約１０¹²から１０¹⁴Ｈｚの周波数そして３ｘ１０^-4から３ｘ１０¹⁶メートルの波長を持つ遠赤外線及び赤外線放射、約１０¹⁶から１０¹⁸Ｈｚの周波数そして３ｘ１０^-8から３ｘ１０^-10の波長を持つ紫外線放射、軟Ｘ−線又はレーザー、陰極線（真空管の陰極から表面に垂直に発する負に荷電した電子の流れ）、Ｘ−線及び１０²¹Ｈｚ以上の周波数そして対応する波長を持つことにより特徴づけられるガンマ線放射、を含む。
当業者にとって明白であるように、エネルギー源により出される放射線の線量が大であれば、所望の結果を達成する為に、葉をそれに当てる必要時間は少ない。典型的には、そのような高周波数の放射線源を使用する場合、一分間以下の、好ましくは３０秒間以下の、更に好ましくは約１０秒間以下の放射線適用時間が必要である。他の方法で定義すれば、少なくとも約１秒間の放射線適用時間が好ましい。然しながら、以下の実施例に示すように、所望により、暴露速度は、放射線量を過剰に出すことにより制御できる。例えば、１メガラドの放射線を瞬間的に（以下の実施例１７で明らかにされる電子ビーム加速器によるように）、又はあらかじめ決定した暴露速度で（以下の実施例１９で明らかにされる、１メガラド（１０キログレイ）の放射線が時間当り約０．８メガラドの暴露速度で出された、密封容器ガンマ線放射試験により例示されるように）出すことができる。高周波数の放射線源を使用する場合、未処理の試料と比較して、少なくともＴＳＮＡｓの５０％減少を達成する放射線量を、使用するのが好ましい。特定の放射線量及び暴露速度は、特定の設備及び適用する放射線源の型によるであろうが、当業者には明白であるように、タバコ試料を約０．１から約１０メガラド、更に好ましくは約０．５から約５メガラド、そして更に好ましくは約０．７５から約１．５メガラドの放射線に当てるのが一般的に好ましい。
以下の実施例に例示するように、試験は種々のタバコ試料に対し、これら追加の放射線源の具体例として加速電子ビーム、ＣＯ₂レーザー、及びガンマ線放射を使用して行われた。各々の事例に於いて。未処理の照射を受けたタバコ試料は、有意に減少された及び／又は実質的に除去された含有量のＴＳＮＡを含むことを明らかにした。
更に本発明のもう一つの態様に於いて、空気再循環式対流オーブンでの、まだ影響を受けやすい状態にあるタバコの処理も又葉の品質は低下したが、ＴＳＮＡを減少することを示した。ＴＳＮＡ含有量の低下に効果的でなくそしてタバコの品質を低下させる、通常の高温乾燥オーブンと異なり、約３８℃から約２６０℃（約１００°から約５００°Ｆ）の温度で、低い温度で１時間から高い温度で約５分間の範囲での空気再循環式対流オーブンでの加熱も又、本明細書で定義した影響を受けやすい状態のタバコの中のＴＳＮＡｓの含有量を効果的に減少し又は形成を阻止した。更にもっと好ましくは、空気再循環対流加熱及びマイクロウェーブ放射を組合わせたオーブンは、葉の品質を改良しながら加熱時間を短縮できる。例えば、対流式オーブンを単独で使用する場合、葉身が乾燥した時点で葉脈及び葉柄は完全に乾燥していなく従って葉身部分は乾燥しすぎそして粉をまぶしたようになる。マイクロウェーブ処理を再循環対流式オーブン加熱と組合わせることは、更に均一に乾燥した産物が得られ葉の品質を改良できる。
他のもう一つの側面に於いて、本発明は、ＴＳＮＡｓを有意に減少し又は実質的に除去したタバコ産物を、消費のために提供することにより、喫煙し、噛み、又は他の方法でタバコを摂取する人間又は動物自体内の、タバコ特有のニトロソアミン含有量を、減少し又は実質的に除去する方法に関する。
未処理のタバコをマイクロウェーブ又は他の放射線エネルギーに当てることは、驚異的に低いニトロソアミン含有量を持つタバコを提供するのに効果的であることを、本明細書で明らかにする。これらの技術は、特に葉柄を廃棄しそして水分圧搾又は上に記載した水蒸気処理を採用しない場合、タバコの葉の三分の一から半分の長さの葉柄を、剥ぎ取りそして処分することにより促進できる。この方法で葉柄を除去した場合、得られたマイクロウェーブ処理済のタバコの葉は、葉柄の所望しない部分が既に除去されているので葉柄除去機の使用を必要としない。結果として、タバコ廃棄物を１０％から３０％減少し、葉柄除去に伴うタバコ産物の典型的な損失を排除する。本発明の改良されたタバコは、紙巻タバコ、葉巻、噛みタバコ、タバコチューインガム、タバコトローチ、タバコポーチ、嗅ぎタバコ、又はタバコ香料及び食品添加物を含む、いかなるタバコ産物中の、標準的方法で処理されたタバコの全て又は一部と、入れ替えることができる。喫煙用の目的に、本発明は、標準的ニコチン含有量で、良好な喫煙特性を維持しそして充分な風味を提供しながら、より少ない不快な匂いを提供する。噛みタバコ、嗅ぎタバコ、ポーチ及び食品添加の目的には、本発明のタバコは、豊かな気持ちの良い香りを持つ。
本発明は、次に以下の実施例を引用することにより例示されるが、これらは本発明の範囲を、いかなる方法によっても制限しようとするものではない。
実施例１
ヴァージニアフルー（ｆｌｕｅ）タバコを採収し、そして葉を煙道処理（ｆｌｕｅ ｃｕｒｉｎｇ）を始めるために、保存小屋に約３８−４３℃（約１００−１１０°Ｆ）で置いた。試料１−３は収穫後約２４−３６時間に、葉が黄色に変色した後小屋から採取した。試料１は、主葉脈を取り、そして約４００−５００℃の対流空気オーブンで高温乾燥し、それにより葉身が褐色化した、葉身試料であった。試料２は、ゴールドスター（Ｇｏｌｄｓｔａｒ）モデルＭＡ−１５７２Ｍマイクロウェーブオーブン（２４５０ＭＨｚ）に入れ、高電力設定（１０００ワット）で回転しながら約２．５分間加熱した、黄色葉であった。試料３は、未処理の対照として使用した、黄色葉であった。試料４及び５は、保存小屋に約８２℃（約１８０°Ｆ）の高温で残され、試料４は、ラックの外側で乾燥され、試料５は、ラックの内側で乾燥された。試料６は、標準的煙道処理法を受けた、処理された褐色葉である。
分析は、各々の試料につきＮＮＮ、ＮＡＴ、ＮＡＢ及びＮＮＫ含有量を測定する為に行った。本実施例及び以下の実施例に於いて、“ＴＳＮＡ”は、これら４種のタバコ特有のニトロソアミンの合計を表す。試料の調整及び抽出はＴＳＮＡｓの分析の典型的方法（例えば、バートン（Ｂｕｒｔｏｎ）等、“タバコ葉組織内のタバコ成分の分布．１．タバコ特有のニトロソアミン、硝酸塩、亜硝酸塩及びアルカロイド”、Ｊ．Ａｇｒｉｃ．Ｆｏｏｄ Ｃｈｅｍ．，Ｖｏｌｕｍｅ４０，Ｎｏ．６，１９９２参照）に従い、そして個々のＴＳＮＡｓは、ヒューレットパッカード（Ｈｅｗｌｅｔｔ−Ｐａｃｋａｒｄ）モデル５８９０Ａガスクロマトグラフに結合したサーメディックス（Ｔｈｅｒｍｅｄｉｃｓ）Ｉｎｃ．ＴＥＡモデル５４３熱エネルギー分析器で定量した。結果を、以下の表１に示す。以下の各々の表の全てのデータは、試料グラム当りのニトロソアミンのマイクログラム（即ち、パーツパーミリオン又はμｇ／ｇ）で示す：

実施例２
ヴァージニアフルータバコを、採収した。試料７は、対照として使用する、新しく切り取った、緑色葉であった。一方試料８は、２．５キロワットで２４５０ＭＨｚで作動する、ケンタッキー州ルイビルのマイクロドライ（ＭｉｃｒｏＤｒｙ）社製の多モードマイクロウェーブ適用器具で、マイクロウェーブ放射を当てた、新しく切り取った緑色葉であった。試料９-１２は、標準的な煙道処理をした褐色タバコから得られた。試料９は、成型した紙巻タバコからのタバコであった；試料１０は、紙巻タバコを製造する為の、ばらの、切断したタバコであった。試料１１及び１２は、各々を試料８と同様なマイクロウェーブ条件に当てた以外は、それぞれ試料９（紙巻タバコ）及び試料１０（ばら）と同じであった。ＴＳＮＡ含有量は、実施例１と同様の方法で分析した。結果を、以下の表２に示す：

実施例３
表３に示す以下の銘柄の紙巻タバコを、ケンタッキー州レキシントンの種々の小売店から無作為に購入し、そして実施例１に記載の方法を使用してＴＳＮＡを分析した：

実施例４
ヴァージニアフルータバコを収穫し、そして葉を煙道処理を始めるために、保存小屋に約３８−４３℃（約１００−１１０°Ｆ）で置いた。収穫後約２４−３６時間後に、葉が黄色に変色した後小屋から出し、ゴールドスターモデルＭＡ−１５７２Ｍマイクロウェーブオーブン（２４５０ＭＨｚ）で、高電力設定（１０００ワット）で回転しながら約２．５分間マイクロウェーブ処理した。葉は、この方法で効果的に乾燥され、褐色に変色しなかったが、しかし代わりにその鮮黄色を保っていた。葉を、切断しそして紙巻タバコを調製した。試料２９−３３は、赤フルフレーバーと標識したバッチから採取し、一方試料３４−３８は、青ライトと標識したバッチから採取した。試料３９−４２は、健康食品店から購入したナチュラルアメリカンスピリットと言う銘柄の紙巻タバコである。試料２９−４２は実施例１記載の方法を使用してＴＳＮＡ含有量を分析し、そして結果を以下の表４に示す：

本明細書中の表中のＳＴＤは、示した試料の平均に対する標準偏差である。
実施例５
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。葉が黄色に変色した後、収穫後処理約２４−３６時間、乾燥室から取り出し、そして前述のＭｉｃｒｏＤｒｙ ｍｕｌｔｉｍｏｄｅ ａｐｐｌｉｃａｔｏｒにおいて出力レベル約６キロワットで約２０及び約３０秒間マイクロ波を照射したものをそれぞれサンプル４３−４４とした。マイクロ波処理後のサンプル４３及び４４は乾燥した黄金色の葉だった。サンプル４５−５１は通常の熱風乾燥工程を経た乾燥した茶色の葉から調製した。サンプル４５は対照；約４００−５００°Fに予熱した対流オーブンで約１及び約３分間加熱したものをそれぞれサンプル４６及び４７とした；そしてＷａｖｅｇｕｉｄｅ ａｐｐｌｉｃａｔｏｒ Ｍｏｄｅｌ ＷＲ−９７５、ＭｉｃｒｏＤｒｙ製大型マルチモードオーブン（出力設定０−７５ＫＷ）において５０キロワットで約１０及び４０秒間マイクロ波（９１５ＭＨｚ）を照射したものをそれぞれサンプル４８及び４９とした。熱風乾燥した葉から調製した刻み（再構成したシート状）タバコをサンプル５０及び５１とした。サンプル５０には導波管マイクロ波オーブンで５０キロワットで約１．５分間マイクロ波を照射し、一方サンプル５１は約４００−５００°Fに予熱した対流オーブンで約３分間加熱した。実施例１に記載した方法を用いてこれらのサンプルについてＴＳＮＡ含有量を測定した、そして結果を以下の表５に示す：

実施例６
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。サンプル５２−５５は、約２４−３６時間後に乾燥室から取り出した黄変タバコから調製した紙巻きタバコであり、そしてＧｏｌｄｓｔａｒ マイクロ波オーブン、Ｍｏｄｅｌ ＭＡ−１５７２Ｍ（２４５０ＭＨｚ）、において高出力設定（１０００ワット）で約２分間マイクロ波を照射したものであった。比較のため、通常の熱風乾燥工程を経た葉から調製した紙巻きタバコで、マイクロ波処理を行わなかったものをサンプル６１及び６２とした。乾燥した葉をサンプル５６；濃黄色で完全には乾燥していないものをサンプル５７；乾燥した葉身をサンプル５８とし、そして乾燥中肋をサンプル５９及び６０とした。実施例１と同様にＴＳＮＡ含有量を測定した、そして結果を以下の表６に示す：

実施例７
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫した。未乾燥で刻んだばかりの緑色タバコをサンプル６３及び６６としたが、しかしＴＳＮＡ測定を行うまでに１週間以上時間が経過したために幾分空気乾燥した。残りの葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。葉が黄色に変色した後、収穫後処理約２４−３６時間、乾燥室から取り出し、そして前述のＷａｖｅｇｕｉｄｅ ｍｕｌｔｉｍｏｄｅ ａｐｐｌｉｃａｔｏｒにおいて２５キロワットで約４０秒間マイクロ波を照射したものをサンプル６８とした。
サンプル６４／６５（葉）及び６７／７０（再構成されたシート状、又は「刻み」タバコ）は、乾燥タバコを水で戻しそしてマイクロ波照射を行った際の本発明の効果を例示する。サンプル６４及び６５は、通常の熱風乾燥工程を経た葉のサンプルであったが；約５−１０秒間流水で処理をすることにより水で戻したものをサンプル６４とした。葉は有意に水分を吸収した。サンプル６４及び６５にはそれぞれその後Ｗａｖｅｇｕｉｄｅ ｍｕｌｔｉｍｏｄｅ ａｐｐｌｉｃａｔｏｒによって２５キロワットで約４０秒間マイクロ波処理を行った。乾燥した葉から調製し、再構成したシート状タバコをサンプル６７及び７０とした。サンプル６７は有意な量を吸収させるために水を加えることにより水で戻し、そしてサンプル６４に記載の条件でマイクロ波を照射した。サンプル７０にはマイクロ波を照射しなかった。乾燥した葉の別のサンプルをサンプル６９、７１及び７２とし、対照として使用した。実施例１と同様にＴＳＮＡ含有量を測定した、そして結果を以下の表７に示す：

実施例８
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。葉が黄色に変色した後、収穫後処理約２４−３６時間、乾燥室から取り出し、そしてＧｏｌｄｓｔａｒ Ｍｏｄｅｌ ＭＡ−１５７２Ｍにおいて高出力設定で約２分間マイクロ波処理をしたものをサンプル７３とした。サンプル７４−７６は通常の方法で熱風乾燥した。サンプル７４は乾燥したものの対照。実施例７（サンプル６４）と同様に水で戻し、そしてＭｉｃｒｏＤｒｙ ａｐｐｌｉｃａｔｏｒ（２４５０ＭＨｚ）において出力レベル約６キロワットで約２０秒間（サンプル７５）及び約４０秒間（サンプル７６）マイクロ波を照射したものをそれぞれサンプル７５及び７６とした。サンプル７７−７９は熱風乾燥した葉から調製した再構成シート状タバコだった。サンプル７７は対照とし、サンプル７８及び７９は実施例７（サンプル６７）と同様に水で戻した。サンプル７８及び７９は、ＭｉｃｒｏＤｒｙ ａｐｐｌｉｃａｔｏｒでそれぞれ約３０秒間マイクロ波処理をした；サンプル７８はオーブンの底に置いたままにしたが、サンプル７９はシート状サンプルをスチロホーム容器の上に置いて数インチ高い位置にした、これによりさらに均一な加熱が可能となった。実施例１と同様にＴＳＮＡ含有量を測定した、そして結果を以下の表８に示す：

実施例９
サンプル８０−８１は小売店で購入したＲｅｄｍａｎ噛みタバコであった。対照をサンプル８０とし、そしてＧｏｌｄｓｔａｒ Ｍｏｄｅｌ ＭＡ−１５７２Ｍにおいて高出力設定で約１−２分間マイクロ波処理をしたものをサンプル８１とした。サンプル８２−８３は小売店で購入したＳｋｏａｌ嗅ぎタバコであった。対照をサンプル８２とし、サンプル８１と同じ方法でマイクロ波処理をしたものをサンプル８３とした。ＴＳＮＡ含有量を測定した、そして結果を以下の表９に示す：

実施例１０
本発明に従って黄変タバコをマイクロ波処理した後においてもＴＳＮＡが蓄積するかどうかを検討するために、実施例４において検討された紙巻きタバコの追加サンプル（−Ａと称する）、サンプル２９、３５及び３９（対照）について、最初にＴＳＮＡ含有量を測定してから７ヶ月よりさらに経過した後に実施例４に記載のとおりＴＳＮＡ含有量を再測定した。結果を以下の表１０に示す：

実施例１１
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。葉が黄色に変色した後、収穫後処理約２４−３６時間、乾燥室から取り出しそしてＧｏｌｄｓｔａｒ Ｍｏｄｅｌ ＭＡ−１５７２Ｍ マイクロ波オーブンにおいて高出力設定で約２から２．５分間マイクロ波を照射した。それぞれの葉は黄金色でそして効果的に乾燥していた。いくつかのサンプル、「粉砕」と称する、をその後粉末状にすり砕いた、それは例えばガム、薬用ドロップ又は食品添加物として有用であろう。葉にマイクロ波処理を行った時点から６ヶ月よりさらに経過した後に、以下のサンプルのＴＳＮＡ含有量を実施例１に記載の方法を用いて測定した。結果を以下の表１１に示す：

実施例１２
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。サンプル１０４及び１０５は、通常の熱風乾燥工程を経ておりマイクロ波処理を行わなかった葉のサンプルであった。乾燥した中肋をサンプル１０４とし、そして乾燥した葉身をサンプル１０５とした。葉が黄色に変色した後、収穫後処理約２４−３６時間、乾燥室から取り出した黄変タバコをサンプル１０６とした。乾燥室から取り出した後、葉にＧｏｌｄｓｔａｒ Ｍｏｄｅｌ ＭＡ−１５７２Ｍ マイクロ波オーブンにおいて高出力設定で約２から２．５分間マイクロ波を照射した。それぞれの葉は黄金色でそして効果的に乾燥していた。乾燥した葉のいくらかをタバコ抽出物を調製する慣用法でさらに処理し、これを分析用にサンプル１０７とした。サンプル１０４−１０７のＴＳＮＡ含有量を実施例１に記載の方法を用いて測定した。結果を以下の表１２に示す：

実施例１３
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。サンプル１０８及び１０９は、通常の熱風乾燥工程を経た葉のサンプルであった。乾燥した葉身をサンプル１０８、そして乾燥した中肋をサンプル１０９とした。サンプル１１０及び１１１は、葉が黄色に変色した後、収穫後処理約２４−３６時間、乾燥室から取り出した黄変タバコであった。乾燥室から取り出した後、サンプル１１０及び１１１を空気循環型対流オーブン、Ｓｈａｒｐ Ｃａｒｏｕｓｅｌ Ｃｏｎｖｅｃｔｉｏｎ／Ｍｉｃｒｏｗａｖｅ Ｍｏｄｅｌ Ｎｏ．Ｒ−９Ｈ８４Ｂで加熱した。約３００°Fで５−１０分間の間迅速に加熱したものをサンプル１１０とした。約１００°Fから始めて１０分間より長い時間をかけて約１５０°Fまで段階的に上昇させ、合計加熱時間２０分間で低温でさらにゆるやかに加熱したものをサンプル１１１とした。サンプル１０８−１１１のＴＳＮＡ含有量を実施例１に記載の方法を用いて測定した。結果を以下の表１３に示す：

対流オーブンによる加熱がＴＳＮＡレベルを減少させることが示されたが、タバコの質は本発明の好ましい実施例に従ったマイクロ波処理により得られるものの質よりも劣っていた。さらに、加熱時間もマイクロ波処理又は他の形態の高周波照射を使用する際よりも必然的に長くなる。詳細には、対流加熱では色を望ましい黄金色に固定することが不可能であったし、そして葉身は乾燥しすぎ、そして従って砕けやすい傾向があった一方で葉脈及び中肋は完全には乾燥されなかった。対照的に、本発明の最も好ましい態様に一致して、マイクロ波処理された葉は効果的に乾燥しそして処理後も黄金色を保持しており、そしてさらなる処理、特に紙巻きタバコ用、のためにしなやかでそして柔軟なままの状態であった。対流オーブン処理サンプルでは、乾燥された葉身は粉末及び細かなタバコ小片に砕けやすかった。
実施例１４
Ｋｅｎｔｕｃｋｙ産バーレータバコを収穫し、そして葉が黄色に変色した後、収穫後処理約２４−３６時間、その葉を以下のとおり処理した。サンプル１１２−１１７は、以下のとおり処理したこの回の原料からの葉のサンプルであった。実施例１２のサンプル１０６とほとんど同じ条件でマイクロ波処理をしたものをサンプル１１２とした。葉は黄金色でそして効果的に乾燥していた。サンプル１１３、及び１１４及び１１７は、実施例１３に記載したものと同じ空気循環型対流オーブンで加熱したものであった。サンプル１１０とほとんど同じ条件で加熱したものをサンプル１１３とし、サンプル１１１とほとんど同じ条件で加熱したものをサンプル１１４とし、そして約３５０°Fで約２０分間加熱したものをサンプル１１７とした。サンプル１１３、１１４及び１１７の質は、実施例１３に記載したサンプル１１０及び１１１の質と類似していた。実施例１３に記載のＳｈａｒｐ Ｃａｒｏｕｓｅｌ Ｃｏｎｖｅｃｔｉｏｎ／Ｍｉｃｒｏｗａｖｅ オーブンで、マイクロ波（３０％）／対流（３００℃）機能を組み合わせて使用し、葉が黄金色に効果的に乾燥するまで加熱したものをサンプル１１５及び１１６とした。サンプル１１２−１１７のＴＳＮＡ含有量を実施例１に記載の方法を用いて測定した。結果を以下の表１４に示す：

実施例１５
Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコを収穫し、そしてその葉を熱風乾燥工程を始めるために約１００−１１０°Fの乾燥室に入れた。サンプル１１８−１２０は、葉が黄変し始めた後乾燥室から取り出し、そしてその直後に対流型台所用電子レンジで約２から２．５分間葉が焼ける又は焦げることなく黄金色に効果的に乾燥するまでマイクロ波を照射した葉のサンプルであった。サンプル１２１−１２３は、収穫しそしてまず黄変した後に以下のとおりそれぞれ処理したＫｅｎｔｕｃｋｙ産バーレータバコのサンプルであった。タバコ産業で慣用される対流蒸気回転乾燥機に温度約２００°Fで葉が茶色になりそしていくぶん乾燥するまで入れておいたものをサンプル１２１とした。既引用のＧｏｌｄｓｔａｒ マイクロ波オーブンで高出力で約２分間マイクロ波処理し、水で戻しそして葉をわずかに茶色くするために、これにより香が強まるとされている、回転乾燥機にいれたものをサンプル１２２とした。１分間マイクロ波処理をしたこと及び回転乾燥機に入れる前に水で戻さなかったことを除いてサンプル１２２と同様に処理したものをサンプル１２３とした。ＴＳＮＡ含有量を実施例１と同様に測定した、そして結果を以下の表１５に示す：

実施例１６
Ｎｏｒｔｈ Ｃａｒｏｌｉｎａ産バーレータバコを収穫し、そして葉が黄色に変色し始めた後、収穫後処理約２−３日、その葉を以下のとおり処理した。前述と同型のＧｏｌｄｓｔａｒ マイクロ波オーブンで高出力設定で約２分間マイクロ波を照射した葉のサンプルをサンプル１１８とした。マイクロ波処理後葉は黄金色でそして効果的に乾燥していた。ＴＳＮＡ含有量を実施例１に記載の方法を用いて測定した。結果を以下の表１６に示す：

実施例１７
本実施例は、黄変タバコサンプルにおいてＴＳＮＡの含有量を減少させる、又は実質的にその合成を阻害するために電子ビーム照射を使用することの効果を例示する。Ｎｏｒｔｈ Ｃａｒｏｌｉｎａ産バーレータバコを収穫した。サンプル１１９−１２２は、葉が効果的に乾燥しそして茶色になるまで通常の方法で屋外につるしておくことにより空気乾燥した葉のサンプルであった。対照のため無処理としたものをサンプル１１９とした。Ｒａｄｉａｔｉｏｎ Ｄｙｎａｍｉｃｓ，Ｉｎｃ．ｏｆ Ｅｄｇｅｗｏｏｄ，Ｎ．Ｙ．製 Ｄｙｎａｍｉｔｒｏｎ Ｅｌｅｃｔｒｏｎ Ｂｅａｍ Ａｃｃｅｌｅｒａｔｏｒを使用してコンベアーベルト上で暴露強度１ ｍｅｇｅｒａｄで電子ビーム照射を行ったサンプルをサンプル１２０及び１２１とした。Ｇｏｌｄｓｔａｒ マイクロ波オーブンで高出力設定で約２分間マイクロ波を照射したものをサンプル１２２とした。黄変し始めた後のバーレータバコの葉の先端を採取してサンプル１２３とした。サンプル１２３と同じ植物体から採取した葉柄部分をサンプル１２４とし、そしてこれはまだいくぶん緑色だった。黄変段階のバーレーサンプルの葉全体をサンプル１２５及び１２６とした。サンプル１２３−１２６のそれぞれに前述のＤｙｎａｍｉｔｒｏｎを使用して、サンプル１２０及び１２１と同様の方法及び同様の暴露強度で前述と同様に電子ビーム照射を行った。上記サンプルについて実施例１において述べた方法に従ってＴＳＮＡ含有量を測定した、そして結果を以下の表１７に示す：

上記データは電子ビーム照射が検討した黄変タバコにおいてタバコ特異的ニトロソアミンの形成を実質量阻害するために効果的であることを示しているが、収穫後処理の同様な段階での葉に本出願の他の実施例において記載される様にマイクロ波照射を行った際のようには葉は効果的に乾燥していなかった。従って、電子ビーム照射法の商業的応用には乾燥工程を促進するために照射済の葉を対流乾燥オーブン内を通過させるなどの追加的な乾燥段階が必要であろう。
実施例１８
本実施例は、本発明の低ＴＳＮＡ目標を達成するためにレーザーから発せられる高エネルギービームもまた効果的であることを例示する。Ｌｕｘａｒ Ｃｏｒｐ．製ＣＯ₂レーザー、Ｍｏｄｅｌ ＬＸ−２０ＳＰを、収穫後処理約２−３日の黄変Ｖｉｒｇｉｎｉａ産ｆｌｕｅタバコ葉への照射に使用した。１秒あたりのパターン数でのアプリケーション速度を決定するｓｕｐｅｒｐｕｌｓｅ Ｅ プログラムでＮｏｖａＳｃａｎ ｈａｎｄｐｉｅｃｅを使用した。１秒あたり１０パターンを照射するＥ１０設定を使用した。葉の８個のサブサンプル、Ｔ−１からＴ−８、に以下の方法に従って照射した：

２ワットにおいて、約１２０ｍＪのエネルギーが各走査又は通過において照射され、一方４ワットにおいては、約２４０ｍＪがそのような各走査において照射された。
サブサンプルＴ−１からＴ−４を混合及び一緒に組み合わせて葉のサンプル１２７とし、実施例１に記載と同様の方法でＴＳＮＡ含有量を評価した。サブサンプルＴ−５からＴ−８を同様に混合及び一緒に組み合わせて葉のサンプル１２８とし、同様にＴＳＮＡ含有量を評価した。結果を以下の表１８に示す：

実施例１７に記載のサンプルついてと同様にＣＯ₂レーザー照射サンプルは、ＴＳＮＡ含有量は低いが、マイクロ波処理サンプルの様には効果的に乾燥されておらず、そして従って乾燥工程を促進するために追加的な乾燥工程を用いることが可能であった。さらに、ＣＯ₂レーザー照射後ＴＳＮＡ測定の前に、８個のサブサンプルのうち６個がいくぶん茶色に変色した、ＴＳＮＡ含有量に明らかな影響は無かった。
実施例１９
本実施例は、黄変タバコにおいて有意量のＴＳＮＡ形成を阻害することにガンマ放射線もまた効果的であることを例示する。収穫後処理約２−３日で、葉が黄色に変色し始めた直後のＶｉｒｇｉｎｉａ産ｆｌｕｅタバコを採取した。サンプル１２９−１３２をそれぞれ黄変葉の葉身部分から採取し、そして遮蔽容器内で１０ ｋＧｒｅｙ（１ ｍｅｇａｒａｄ）のガンマ線、暴露強度１時間あたり８ｋＧｒｅｙ（．８ ｍｅｇａｒａｄ）で合計暴露時間約７５分間、を照射した。続いて照射済サンプルについて前述と同様の方法でＴＳＮＡ含有量を評価した、そして結果を以下の表１９に示す：

本請求の発明の意図及び範囲から解離することなく多くの変更及び改変を好ましい態様において行うことも可能であることは当業者に明白である。従って、前述の記載は例示することのみを意図しそして制限する目的では考慮されるべきではない。 Field of Invention
The present invention relates to a method for treating tobacco to reduce or prevent the formation of harmful nitrosamines normally present in tobacco. The invention also relates to tobacco products with a low nitrosamine content.
Cross references to related applications
This application is a continuation-in-part of application serial number 08 / 671,718 filed June 28, 1996, and is now a part of the continuation-in-part of application serial number 08 / 725,691 filed September 23, 1996, which is now abandoned. A continuation-in-part of application serial number 08 / 739,942 filed on Oct. 30, 1996, which is now abandoned, and a continuation-in-part of application serial number 08 / 757,104 filed December 2, 1996, This is a continuation-in-part of application serial number 08 / 879,905 filed on June 20, 1997. This application and the applications listed above claim priority to provisional application serial number 60 / 023,205 filed August 5, 1996, except for application serial number 08 / 671,718 filed June 28, 1996.
Background of the Invention
Another person has described the use of microwave energy to dry crops. The use of microwave energy to store tobacco is disclosed in US Pat. No. 4,430,806 to Hopkins. In US Pat. No. 4,898,189, Wochnowski teaches the use of microwaves to treat green tobacco for the purpose of controlling moisture content in preparation for storage or shipment. US Pat. No. 3,699,976 describes that microwave energy can mitigate tobacco insect attack. In addition, a method (US Pat. No. 4,821,747) using an impregnation of an inert organic liquid into tobacco for the purpose of extracting the swollen organic material by means of washing with running water is disclosed. Was exposed to microwave energy. In another embodiment, microwave energy is disclosed as a technique for drying sucked tobacco-containing material (US Pat. No. 4,874,000). In US Pat. No. 3,773,055, Stungis discloses the use of microwaves to dry and expand cigarettes made from wet tobacco.
Prior attempts to reduce tar and harmful carcinogenic nitrosamines included first using filters on smoking tobacco. In addition, attempts have been made to use additives to prevent the effects of harmful carcinogens in tobacco. These efforts did not reduce the tumor prevalence associated with tobacco use. Freshly picked green tobacco is known to be substantially free of nitrosamine carcinogens. See Wiernik et al., “Effect of Air-Curing on the Chemical Composition of Tobacco,” Recent Advances in Tobacco Science, Vol. 21, pp. 39, Symposium Proceedings 49th Meeting Tobacco Chemists' Research Conference, Sept. 24-27, 1995. Lexington, Kentucky (hereinafter "Wiernik et al.") And the like. However, the stored tobacco contains the harmful carcinogens N'-nitrosonornicotine (NNN) and 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK), It is known to contain a large number of nitrosamines. It is widely accepted that such nitrosamines are formed during the storage process after harvest as further described herein. Unfortunately, freshly picked green tobacco is not suitable for smoking or other consumption.
In 1993 and 1994, as summarized in “Reduction of Nitrite-Nitrogen and Tobacco N'-Specific Nitrosamines In Air-Cured Tobacco By Elevating Drying Temperatures”, Agronomy & Phytopathology Joint Meeting, CORESTA, Oxford 1995 In addition, Burton et al. At the University of Kentucky conducted an experiment focusing on tobacco-specific nitrosamines (TSNA). Burton et al., At various stages of the air storage process, including End of Yellowing (EOY), EOY + 3, EOY + 5, etc., dried harvested tobacco leaves for 24 hours at 71 ° C resulting in nitrosamine levels. Reported some decrease. Reference is also made to lyophilization and microwave radiation of a sample without details or results. Applicants have confirmed that the microwave action was considered a failure of the actual action underlying this gist performed by Burton et al. At the University of Kentucky. An aspect of Burton et al's 1993-94 study is reported on pages 54-57 of Wiernik et al. Under the title "Modified Air-Curing". According to an article by Wiernik et al., When tobacco leaf samples taken at various stages of the air storage process were subjected to rapid drying at 70 ° C for 24 hours, excess water was removed and microbial growth was reduced. It is hypothesized that accumulation of nitrite and tobacco-specific nitrosamines (TSNA) will be avoided. In Table II on page 56, Wiernik et al. Include some of Burton's summary data on leaflet and main vein nitrite and TSNA content in KY160 and KY171 samples. Data from freeze-drying and rapid drying tests are included, but there is no mention of microwave-radiated samples. The article includes the following conclusions:
From this study, it may be possible to reduce leaf and main nitrite levels and TSNA accumulation by adding heat (70 ° C) to dark tobacco after loss of cellular integrity in the leaves It can be concluded. Rapid drying of tobacco leaves at this stage of the storage process attenuates the microbial activity that occurs during the slow storage process at ambient temperatures. However, it must be added that such treatment reduces the quality of tobacco leaves.
56 pages of the book. The article by Weirnik et al. Also discusses the traditional storage process of Polish Skroniowski tobacco as an example of a two-stage storage process. The article states that tobacco is first stored in air and if the leaves are yellow or brownish, the tobacco is heated to 65 ° C for 2 days to store the stem. Analysis of tobacco produced by this method showed that both nitrite and TSNA values were low, ie, less than 10 micrograms per gram and 0.6-2.1 micrograms per gram, respectively. Weirnik et al. Theorized that these results could be explained as a result of rapid heating that did not allow the microorganisms to grow further. However, Weirnik et al. Also noted that low nitrite and TSNA values of 15 micrograms per gram of nitrite and 0.2 micrograms per gram of TSNA were obtained for cigarettes subjected to air storage treatment in Poland. .
Summary of the Invention
One object of the present invention is to substantially eliminate or reduce the content of nitrosamines in tobacco intended for consumption by smoking or other means.
Another object of the invention is to reduce the carcinogenic potential of tobacco products, including cigarettes, cigars, chewing tobacco, snuff and gums containing tobacco and lozenges.
Yet another object of the present invention is to provide N′-nitrosonornicotine (NNN), 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK) in such tobacco products. ), Substantially eliminating or significantly reducing the amount of tobacco-specific nitrosamines, including N′-nitrosoanatabine (NAT) and N′-nitrosoanabasin (NAB).
Another object of the present invention is to treat unstored tobacco at an appropriate time after harvest so as to suppress the storage process without adversely affecting the suitability of tobacco for human consumption. .
Another object of the present invention is to reduce the content of tobacco-specific nitrosamines in fully stored tobacco.
Yet another object of the present invention is to provide a tobacco product suitable for human consumption that contains a substantially reduced amount of tobacco-specific nitrosamine, thereby reducing the carcinogenic potential of the tobacco product. To reduce the content of tobacco-specific nitrosamines, especially NNN and NNK, and their metabolites in humans who smoke, consume tobacco or ingest tobacco in some other form. Preferably, the tobacco product is a cigarette, cigar, chewing tobacco or a gum or lozenge containing tobacco.
These and other objects and advantages in accordance with the present invention can be achieved by a process that reduces or prevents the formation of nitrosamines in harvested tobacco plants, including:
To reduce or substantially reduce the amount of at least one nitrosamine so that at least a portion of the plant is not preserved and the amount of nitrosamine can be reduced or reduced. Subjecting said part to microwave radiation for a sufficient amount of time
Is included.
In this process of the present invention, the step of subjecting to microwave radiation is performed on tobacco leaves or portions thereof after the yellowing of the leaves has started and before the tobacco-specific nitrosamines have substantially accumulated in the leaves. Preferably it is done. In this process of the present invention, the step of subjecting to microwave radiation is preferably performed before substantial loss of leaf cell integrity.
In another preferred embodiment of this process, the tobacco is flue tobacco and the step of subjecting to microwave radiation is performed within about 24 to about 72 hours after harvesting, and even more preferably within about 24 to about 36 hours after harvesting. Is called.
In yet another aspect of this process, the harvested tobacco is maintained at the ambient temperature conditions in a controlled environment prior to the step of subjecting to microwave radiation.
A preferred aspect of this process is that, prior to subjecting the tobacco leaf, preferably containing the stem, to microwave radiation, the leaf is physically squeezed and then excessed to ensure more uniform drying by microwave units. A step of squeezing out moisture is included. This step can be conveniently performed by passing the leaves through a pair of cylindrical rollers that rotate appropriately spaced before entering the microwave cavity.
In yet another preferred embodiment of the present invention, the microwave radiation has a frequency of about 900 to about 2500 MHz and for this plant for a predetermined amount of power for at least 1 second, preferably about 10 seconds to about 5 minutes. Added. The amount of power used generally determines the length of time the cigarette is subjected to microwave radiation, ranging from about 600 to about 1000 watts when using a conventional kitchen microwave oven, for industrial multimode applicators. Can be up to hundreds or more of a kilowatt. The preferred amount of power using an applicator designed to treat individual leaves ranges from about 2 to about 75 kilowatts, more preferably from about 5 to about 50 kilowatts, which is a relatively rapid treatment Make it executable.
It is also preferred according to the present invention to apply microwave radiation to the leaves and parts thereof for a time suitable for effective drying of the leaves without darkening so that it is suitable for human consumption.
The present invention relates to tobacco-specific compounds such as N′-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N′-nitrosoanatabine and N′-nitrosoanabasin. Attempts are also being made to subject tobacco leaves to microleaf radiation in order to prevent the normal accumulation of at least one nitrosamine.
The invention, in its broadest form, also encompasses tobacco products comprising non-green tobacco that are suitable for human consumption and have a lower content of at least one tobacco-specific nitrosamine than normally stored tobacco.
In a preferred embodiment, the non-green tobacco product has a TSNA (NNN, NNK, NAB and NAT) content of 0.2 μg / g or less, more preferably about 0.15 μg / g or less, and even more preferably about 1 μg / g or less. The NNN content is about .15 μg / g or less, more preferably about .10 μg / g or less, even more preferably about .05 μg / g or less, and the NNK content is about .002 μg / g or less, more preferably about .001 μg. / g or less, even more preferably about .0005 μg / g or less.
The present invention is also directed to tobacco products comprising dry yellow tobacco that are suitable for human consumption and have a lower content of at least one tobacco-specific nitrosamine than tobacco stored as normal. In a preferred embodiment, the yellow tobacco product has a TSNA (NNN, NNK, NAB and NAT) content, NNN content, and NNK content within the above preferred ranges.
In other embodiments, the non-green or yellow tobacco product is suitable for human consumption and has a TSNA (NNN, NNK, NAB and NAT) content of freshly harvested green tobacco crop from which the product is manufactured Non-green or yellow tobacco that is within about 25% by weight of the content of such TSNA in it is included. More preferably, the non-green or yellow tobacco product has a TSNA content of no more than about 10% by weight relative to such TSNA content in the freshly harvested tobacco crop from which the product is produced. Preferably it is within about 5% by weight, and most preferably is essentially close (eg, within an amount of up to a few percent by weight). A non-green or yellow tobacco product is suitable for human consumption and has a content of at least one TSNA selected from NNN, NNK, NAB and NAT in the freshly harvested tobacco crop from which the product is produced Less than about 25% by weight, preferably less than about 10% by weight, more preferably less than about 5% by weight, most preferably essentially close to the corresponding TSNA or TSNAs content (e.g., number by weight It is also preferred to include non-green or yellow tobacco, such as up to a percentage.
In yet another aspect of the invention, non-green or yellow tobacco products are suitable for human consumption and have a TSNA (NNN, NNK, NAB and NAT) content from the same tobacco harvest as the products of the invention. At least about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight, and most preferably about 99% by weight, than such TSNA content in the same type of tobacco product Non-green or yellow tobacco, such as low, is stored in the absence of microwave radiation or other techniques designed to reduce TSNA content. A non-green or yellow tobacco product, suitable for human consumption and having a content of at least one TSNA selected from NNN, NNK, NAB and NAT of the same type produced from the same tobacco crop as the product of the invention Appear to be at least about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight, and most preferably at least 99% by weight below the content of the corresponding TSNA or TSNAs in the tobacco product Preferably, non-green or yellow tobacco is included, but it has been stored in the absence of microwave radiation or other techniques.
A preferred form of the invention has a reduced content of at least one tobacco-specific nitrosamine, while the tobacco has not been stored and the formation of at least one tobacco-specific nitrosamine can be prevented while It relates to tobacco products containing tobacco, such as produced by a process involving subjecting tobacco to microwave radiation.
In another aspect, the invention provides:
Rehydrating the stored brown tobacco, and
Subjecting rehydrated tobacco to microwave radiation for a predetermined amount of time with a predetermined amount of energy
A method for reducing the content of at least one tobacco-specific nitrosamine in stored brown tobacco, comprising:
Similarly, within the scope of the present invention,
Rehydrating the stored brown tobacco, and
Subjecting rehydrated tobacco to microwave radiation for a predetermined amount of time with a predetermined amount of energy
Tobacco products comprising stored brown tea with reduced content of at least one tobacco-specific nitrosamine produced by a process comprising:
In yet another aspect, the present invention provides:
The harvested tobacco leaves are not preserved and the amount of tobacco-specific nitrosamines can be reduced or the formation of tobacco-specific nitrosamines can be suppressed, so that Subjecting the leaves to microwave radiation for a time sufficient to reduce the amount in the leaves or substantially reduce formation; and
Creating a tobacco product containing microwave-radiated leaves, wherein the tobacco product is selected from cigarettes, cigars, chewing tobacco, snuff and gums including tobacco and lozenges
Relating to a method for producing a tobacco product.
Using the form of electromagnetic radiation with higher frequencies and shorter wavelengths than the microwave domains discussed above and discussed in more detail below, the fundamental aspect of the present invention is the microwave embodiment. Treating tobacco in such an energy form during the same post-harvest time frame discussed and considered above can achieve reducing or substantially eliminating TSNA in tobacco products That was also discovered. Therefore, the present invention
Reduce or substantially reduce the amount of at least one nitrosamine so that a portion of the harvested tobacco plant is not preserved and the amount of nitrosamine can be reduced or reduced. Subjecting said part to radiation for a sufficient amount of time
including,
It also relates to methods for reducing the content or suppressing the formation of nitrosamines in the plant.
In the process of the present invention, the step of subjecting radiation having a higher frequency than the microwave domain to the tobacco after the onset of leaf yellowing and prior to substantial accumulation of tobacco-specific nitrosamines in the leaf. It is preferable to be performed on the leaf or a part thereof as in the microwave embodiment. In the process of the present invention, it is also preferred that the step of subjecting to radiation is performed before substantial loss of leaf cell integrity. Preferred energy sources that are capable of causing such radiation are further described below, far infrared and infrared radiation, UV (ultraviolet radiation), X-rays or lasers susceptible to magnetisation, electron beams, X-rays and Includes accelerated particle beams such as gamma radiation.
[Brief description of the drawings]
FIG. 1 is a photograph illustrating “yellow” Virginia flue tobacco aged 24 to 72 hours after harvest.
FIG. 2 is a photograph illustrating a “yellow” Virginia flue tobacco radiated with low nitrosamine microwaves in accordance with the present invention.
FIG. 3 is a partial side view of a mobile, industrial scale microwave applicator that can be used to perform microwave processing in accordance with the present invention.
Detailed Description of the Invention
The storage conditions during any given storage process include differences in varieties, differences in leaves harvested from various stem positions, differences in the storage sheds used, and the environment during individual seasons or across different seasons. It has been said that cigarette storage treatment is actually a technology rather than a science because it must be adjusted to take into account changes in the environment, especially weather fluctuations in the case of air storage treatment. For example, the fruit preservation process is somewhat empirical and is best performed by someone who has gained experience with this technology for a considerable period of time. For example, Peele et al., “Chemical and Biochemical Chaneges During The Flue Curing of Tobacco,” Recent Advances In Tobacco Science, Vol. 21, pp. 81, Symposium Proceedings 49th Meeting Chemists' Research Conference, September 24-27, 1995, Lexington. , Kentucky (hereinafter referred to as “Peele et al.”). Thus, those skilled in the art of tobacco storage understand that the external parameters of the present invention, in its broadest form, can vary to some extent depending on the precise set of factors above for any given harvest. will do.
In a preferred embodiment, the present invention is based on the discovery that there are certain times during the storage cycle of tobacco such that tobacco can be processed in a way that would completely prevent the formation of TSNA. . Of course, the exact time period during which TSNA formation can be effectively removed or substantially reduced is the type of tobacco, the method of storage, and many others, including those mentioned above. It depends on the variable. In accordance with this preferred embodiment of the present invention, this time period is past the time when the leaf is cut or past the “green” stage and prior to the time when TSNA and / or nitrite substantially accumulates in the leaf. Corresponds to a post-harvest time frame, which is typically in the yellow phase when the leaf is undergoing a yellowing process or before the leaf begins to turn brown, and cell integrity is substantially It corresponds to a period before being lost. Unless otherwise apparent from the context, the terms “substantial” and “significant” as used herein are generally predominant or predominant on a relative scale. Say that. During this time frame, as discussed further below, by exposing the tobacco to microwave radiation for a predetermined length of time with a predetermined amount of energy, the leaves substantially prevent TSNA formation, or It is possible to reduce the content of any already formed TSNA. This microwave treatment substantially reduces the natural formation of TSNA and provides dried, bright yellow leaves suitable for human consumption. Application of microwave energy to the leaves according to the present invention effectively suppresses the original TSNA formation cycle, if TSNA has already begun to substantially accumulate, typically around the end of the yellow season. Thus preventing further substantial formation of TSNA. If yellow or yellowing tobacco is processed in this manner at the most suitable point in the storage cycle, the resulting tobacco product is essentially close to that of freshly harvested green tobacco, On the other hand, it maintains its aroma and taste.
In another aspect, the present invention provides a method for rehydrating stored tobacco and subjecting the rehydrated stored tobacco to microwave radiation as further described below. It relates to the treatment of (brown) tobacco to effectively reduce the TSNA content of stored tobacco.
The present invention is also applicable to the processing of harvested tobacco intended for human consumption. Much research has been done on tobacco, especially with respect to tobacco-specific nitrosamines. Freshly harvested tobacco leaves are called “green” tobacco and contain no known carcinogens, but green tobacco is not suitable for human consumption. The process of storing green tobacco depends on the type of tobacco harvested. For example, virginia flu (bright) tobacco is typically fluted, whereas burley and certain dark lines are typically air-cured. Compared to 1 to 2+ months of air storage processing, the tobacco storage processing typically takes place between 5 and 7 days. According to Peele et al., The preservative treatment is generally in three stages: yellowing at about 36-72 hours (35-40 ° C) (eg, certain Virginia flue lines are at about 24 hours, etc.) Some report that it begins earlier than 36 hours.), Divided into 48 hours of leaf drying (40-57 ° C) and 48 hours of main vein (stem) drying (57-75 ° C). Yes. Many major chemical and biochemical changes begin during the yellowing phase and continue throughout the early stages of leaf drying.
In a typical fruit preservation process, the yellowing stage takes place in a barn. During this period, green leaves gradually lose color with the corresponding appearance of yellow carotenoid pigments due to the degradation of chlorophyll. According to a review by Peele et al., The yellowing phase of the flue-cured tobacco is achieved by closing the outdoor air vent in the storage room and maintaining the temperature at approximately 35-37 ° C. This process utilizes a controlled environment, maintains relative humidity in the shed at approximately 85%, limits water loss from the leaves, and leaves the metabolic processes that began in the field to the leaves. The operator continually monitors the storage process, primarily by observing the loss of chlorophyll and green color from the leaves and the development of a fresh orange leaf color from the target lemon.
For one particular varieties of Virginia flue tobacco tested as described herein, freshly harvested green tobacco is about 24-48 hours at about 100-110 ° F. Keep it in the storage room until it turns almost yellow (see Figure 1). Yellow tobacco has a reduced moisture content, ie, about 90 weight percent when green, and about 70-40 weight percent when yellow. At this stage, yellow tobacco contains essentially no known carcinogens and the TSNA content is essentially the same as freshly cut green tobacco. The Virginia flue tobacco typically stays in the yellow stage for about 6-7 days, after which time the leaves turn from yellow to brown. Brown Virginia flue tobacco typically has a moisture content of about 11 to about 15 weight percent. The conversion of tobacco from yellow to brown results in the formation and substantial accumulation of nitrosamines, increasing the microbial content. The exact mechanism by which tobacco-specific nitrosamines are formed is not clear, but is believed to be enhanced by microbial activity involving microbial nitrate reductase during nitrite formation during the preservation process.
Tobacco-specific nitrosamines are amines, NO₂, N₂O_ThreeAnd N₂O_FourIt is thought that it is formed when it reacts with molecular species having a nitroso group derived from nitrous acid under acidic conditions. Weirnik et al. Discuss the hypothesized TSNA formation on pages 43-45 and give a brief overview below.
Tobacco leaves contain a large amount of amines in the form of amino acids, proteins and alkaloids. The quaternary amine nicotine (shown as (1) in the figure below) is the major alkaloid in tobacco, but the other nicotine-type alkaloids are the secondary amines nornicotine (2) and anatabine (3 ) And anabasine (4). Tobacco generally also contains 5% nitrate and very little nitrite.
The nitrosation of nornicotine (2), anatabine (3) and anabasine (4) is performed by the corresponding nitrosamines, namely N'-nitrosonornicotine (NNN, 5), N'-nitrosoanatabine (NAT, 6) and N ' -Produces nitrosoanabasin (NAB, 7). Nitrosation of nicotine (1) in aqueous solution is performed by 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone (NNK, 8) (NNN, 5) and 4- (N -Nitrosomethylamino) -4- (3-pyridyl) -1-butanol (NNA, 9) is given. TSNA, which is generally not so common, includes NNAL (4-N-nitrosomethylamino-1- (3-pyridyl) -1-butanol, 10), isoNNAL (4-N-nitrosomethylamino-4- (3- Pyridyl) -1-butanol, 11) and isoNNAC (4- (N-nitrosomethylamino) -4- (3-pyridyl) -butanoic acid, 12). The formation of these TSNAs from the corresponding tobacco alkaloids is illustrated below (reproduced from page 44 of Weirnik et al. Above) using the 1-12 designation above.

It is now generally agreed that green, freshly harvested tobacco contains virtually no nitrite or TSNA, and that these compounds occur during tobacco storage and storage. ing. In the past decade, studies have attempted to determine events related to TSNA formation during tobacco storage and several important factors have been identified. These include plant genotype, plant maturity at harvest, storage conditions and microbial activity.
Studies have shown that nitrite and TSNA are after the end of yellowing, for example, 2-3 weeks after harvesting for certain air-carrying strains, and about 1 week after harvesting for varieties that are stored in full. It was shown to accumulate during the air storage process for the time starting and ending when the leaves turn completely brown. This is the time during which loss of water and loss of cell integrity due to leakage of cell contents into the cell gap occurs. Therefore, there is a short period of time during the air storage process when cells break down and microorganisms make available nutrients. Weirnik et al. Suggested that as a result of the catabolism of nitrate, in turn, nitrite accumulates substantially, thus allowing the formation of TSNA.
As quoted by Weirnik et al., There are few published reports on the effects of microbial flora on tobacco leaves during the growing and storage process and on stored tobacco. However, the involvement of microbial nitrite reductase in the formation of nitrate during storage is postulated. When the cell structure collapses after the yellow phase and nutrients are made accessible to invading microorganisms, these produce nitrite under favorable conditions, i.e. high humidity, optimal temperature and anoxia. obtain. There is usually a somewhat shorter “time zone” at which time the water activity is still high enough and the cellular structure has collapsed.
In accordance with the present invention, the formation of TSNA in tobacco is substantially prevented or suppressed by subjecting the harvested leaves to microwave radiation under the conditions described herein. In a preferred embodiment, tobacco leaves are exposed to microwave energy at a time between the onset of yellowing and the substantial loss of cell integrity. For optimal results, it is preferable to pass the harvested leaves through the microwave field as a single leaf, as opposed to combined or stacked leaves. Treatment of leaves in this manner has been determined to completely or substantially prevent the formation of tobacco-specific nitrosamines including the known carcinogens NNN and NNK.
According to a preferred embodiment of the present invention, it is possible to obtain a non-green and / or yellow tobacco product suitable for human consumption and having a lower content of at least one tobacco-specific nitrosamine than normally stored tobacco. it can. Green or fresh tobacco is generally not suitable for human consumption as noted above, but “non-green” as used herein means that tobacco is at least This means that you have lost most of the chlorophyll, including partially yellow leaves, completely yellow leaves and leaves that began to turn brown in some places without restriction. In a preferred embodiment, the non-green tobacco product has a TSNA (NNN, NNK, NAB and NAT) content of no more than 0.2 μg / g, more preferably no more than about .15 μg / g, even more preferably no more than about 0.1 μg / g. The NNN content is about .15 μg / g or less, more preferably about .10 μg / g or less, even more preferably 0.05 μg / g or less, and the NNK content is about 0.002 μg / g or less, more preferably about .001 μg. / g or less, even more preferably .0005 μg / g or less. As noted above, given the numerous factors that can affect TSNA formation in tobacco, those skilled in the art will appreciate that these numbers are not absolute, but rather are in the preferred range.
The present invention is also directed to tobacco products comprising dried yellow tobacco that are suitable for human consumption and have a lower content of at least one tobacco-specific nitrosamine than tobacco that has been routinely stored. . In a preferred embodiment, the yellow tobacco product has a TSNA (NNN, NNK, NAB and NAT) content, NNN content, and NNK content within the above preferred ranges.
In other embodiments, the non-green or yellow tobacco product is suitable for human consumption and has a TSNA (NNN, NNK, NAB and NAT) content of freshly harvested green tobacco harvested from which the product is manufactured. Non-green or yellow tobacco that is within about 25% by weight of the content of such TSNA in the product is included. More preferably, the non-green or yellow tobacco product has a TSNA content of no more than about 10% by weight relative to such TSNA content in the freshly harvested tobacco crop from which the product is produced. Preferably it is within about 5% by weight, and most preferably is essentially close (eg, within an amount of up to a few percent by weight). For example, according to the present invention, it is possible to produce tobacco products whose TSNA content is within the ranges described above, while tobacco stored normally from the same crop is freshly cut. Will produce many times the amount of TSNA in tobacco. The present invention can effectively stay in the low amount of nitrosamines found in freshly cut green tobacco. A freshly harvested green tobacco crop that is suitable for human consumption and has at least one TSNA content selected from NNN, NNK, NAB and NAT for non-green or yellow tobacco products from which the product is manufactured Within about 25% by weight, preferably within about 10% by weight, more preferably within about 5% by weight, and most preferably essentially close to the content of the corresponding TSNA or TSNAs in (e.g., by weight It is also preferred that non-green or yellow tobacco is included, such as up to a few percent). In other words, compared to the amount of NNN in freshly cut green tobacco, the content of eg NNN in the tobacco of the present invention is reduced within the above range, or in freshly cut green tobacco Compared with the amount of NNN + NNK, the content of NNN + NNK, etc. in the tobacco of the present invention decreases within the above range, etc. In making these comparisons, fresh green tobacco is analyzed for TSNA content, preferably within about 24 hours after harvest.
In yet another aspect of the present invention, non-green or yellow tobacco products are suitable for human consumption and have a TSNA (NNN, NNK, NAB and NAT) content from the same tobacco harvest as the products of the present invention. More than about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight, and most preferably about 99% by weight than such TSNA content in the same type of tobacco product made. Non-green or yellow tobacco, such as% low, is stored in the absence of microwave radiation or other techniques designed to reduce TSNA content. A non-green or yellow tobacco product, suitable for human consumption and having a content of at least one TSNA selected from NNN, NNK, NAB and NAT of the same type produced from the same tobacco crop as the product of the invention Appear to be at least about 75% by weight, preferably at least about 90% by weight, more preferably at least about 95% by weight, and most preferably at least 99% by weight below the content of the corresponding TSNA or TSNAs in the tobacco product Preferably, non-green or yellow tobacco is included, but it has been stored in the absence of microwave radiation or other techniques. In these embodiments, the percent weight comparison of TSNA is the same as when dried yellow tobacco was produced using, for example, cigarettes made using dried yellow tobacco according to the present invention. It can be made by using cigarettes made from harvested tobacco, but stored by conventional means without subjecting it to microwave radiation.
The stage of yellowing such that the process of subjecting tobacco leaves to microwave radiation is preferably performed can be broadly defined by any one of the following methods. (A) by examining the leaf color when green is replaced by a substantially yellowish color; (b) by measuring the rate of conversion of chlorophyll to sugar; (c) typical By observing the onset of either nitrite formation or nitrosamine formation, which occurs simultaneously with the end of the yellow period; or (d) when, for example, the leaves are about 40 to about 70 percent moisture by weight For example, by measuring the moisture content of the leaves. When microwave radiation is applied to green tobacco, no inhibition or inhibition of nitrosamine formation is observed. However, when microwave energy is applied after the onset of yellowing and before loss of cellular integrity or substantial accumulation of TSNA in the leaves, the amount of observed nitrosamines is reduced or prevented from forming Is dramatic and surprising, as shown by the data discussed below.
The optimal time for the harvested tobacco to be subjected to microwave radiation during the yellow season depends on a number of factors, including variety and environmental changes. Thus, within the time frame starting with the onset of yellowing (defined for example by the loss of most of the green color of the leaf) and until the point at which the leaf substantially loses cell integrity (when it turns brown) One skilled in the art could determine the optimal time for microwave treatment for any particular tobacco variety. For example, for certain genotypes, the present specification may be used to identify the relative time during a specific storage cycle, where significant TSNA accumulation begins, or to identify transitional phases where loss of cellular integrity occurs. Sample leaves were analyzed by the procedure described in the book and either nitrite or TSNA content could be measured. While subjecting the leaves to microwave radiation prior to significant TSNA accumulation is the most preferred form of the method of the present invention, the principles of the present invention are in the process of TSNA formation or a significant amount of TSNA is applied. It can also be applied to already accumulated tobacco leaves. If microwave radiation is performed at this late stage, further formation of TSNA can be effectively suppressed. However, once the leaves have been fully preserved, the amount of TSNA is essentially stable and the application of microwave irradiation is effective in reducing TSNA content except under the rehydration conditions described below. Absent.
When subjected to microwave radiation in accordance with the present invention, tobacco leaves generally have a reduced moisture content, ie, less than 10% baked by weight and often around 5%. If desired, return to the typical moisture range (eg, about 11-15% for Virginia Flue) for brown, stored tobacco before being made into tobacco products such as cigarettes Leaves can be rehydrated.
The present invention is applicable to all lines including fruity or bright varieties, Barley varieties, dark varieties, Oriental / Turkish varieties, and the like. Within the scope of the guidance provided herein, one of ordinary skill in the art could determine the most effective time during the storage cycle to perform the microwave process in order to achieve the objects and advantages of the present invention. .
A preferred aspect of this process is that, prior to subjecting the tobacco leaf, preferably containing the stem, to microwave radiation, the leaf is physically squeezed and then excessed to ensure more uniform drying by microwave units. A step of squeezing out moisture is included. This step can be conveniently performed by passing the leaves through a pair of cylindrical rollers that rotate appropriately spaced before entering the microwave cavity. Such a squeezing process will help squeeze out moisture from the stem, to a lesser extent the main and larger veins, leading to a better and more uniformly dried product. The rollers are made of hard rubber, plastic or steel and can be of any desired length, preferably about 1/8 to about 1/4 inch apart, the distance being It is preferably selected and can vary to accommodate the thickness of a single leaf. The roller can be a belt or chain that is driven by a suitably selected motor. As will be apparent to those skilled in the art, in addition to the rotating rotor, other types of compression or compression means could be used to achieve the same results, if desired.
The preferred embodiment of squeezing the leaves described above does not require the petiole to be excised, and allows microwave production times to be reduced, thus allowing faster production to be performed. This embodiment is particularly beneficial for tobacco leaves intended for use in cigarettes that typically contain a small amount of tobacco petal as part of the mixture. Also, for applications where the petiole is removed from the leaf and discarded, the squeezing step can be omitted if desired.
In another preferred embodiment, instead of squeezing the leaves or excising the petiole, the leaves can be subjected to a steam treatment prior to the microwave treatment. Similar to the squeezing process, steam treatment of the entire leaf, including the petiole, distributes the moisture in the petiole and the thick vein more evenly, which results in a more uniform drying of the whole leaf in the microwave treatment. It became clear. As a result, when this special technique is employed, the entire leaf including the petiole can be used for tobacco products. Details may be apparent to those skilled in the art, but the leaves are placed in a suitable steaming vessel for a time sufficient to make the leaves slightly soft and pliable, typically between about 30 seconds and about 5 minutes. In this case, good results were obtained.
The principles of the invention can also be applied to resoaked, brown or already treated tobacco. In such a case, a significant and unexpected decrease in the amount of TSNAs, especially NNN and NNK, is observed when resoaked brown tobacco is exposed to microwave radiation, but this result shows that the present invention Untreated yellow tobacco is not as striking as when a substantial amount of TSNAs or nitrite is applied before the leaf accumulates. Nevertheless, the addition of moisture to the treated leaves, such as by spraying with sufficient water to effectively soak the leaves, followed by microwave treatment of the resoaked leaves is evident in the following examples. To reduce the TSNAs content.
As described above, when treating treated or brown tobacco, microwave treatment alone has only a minor effect on the nitrosamine content. However, before the treated tobacco was exposed to microwave radiation, it was determined that re-immersing it promotes the action of microwave energy to reduce nitrosamines. In one preferred embodiment, the treated tobacco product is re-soaked by adding an appropriate amount of water, usually at least about 10% by weight, up to a maximum of absorption capacity, directly to the leaves. By exposing the resoaked leaves to microwave radiation in the same manner as described for untreated tobacco herein, the nitrosamine content is reduced as shown below. The leaves can be wetted by any suitable method. If the treated tobacco is in a form other than leaf, such as reconstituted “lamellar” tobacco, it can likewise be re-soaked with, for example, 10-70 wt% water and then microwave treated. Appropriate microwave conditions can be selected depending on the degree of leaf re-soaking, but typically fall within the range of variables described above for microwave processing of yellow tobacco.
According to the present invention, microwave treatment of resoaked brown tobacco includes TSNA (NNN, NNK, NAB and NAT) content, measured individually or collectively, in the treated brown tobacco prior to resoaking. The amount of TSNA being reduced can preferably be reduced by at least about 25% by weight, more preferably at least about 35% by weight and even more preferably at least about 50% by weight.
As used herein, the term “microwave radiation” refers to electromagnetic energy in the form of microwaves having a frequency and wavelength typically characterized as the microwave region. The term “microwave” generally refers to the portion of the electromagnetic wave band that lies between the far infrared region and the normal radio frequency band. The range of microwaves extends from a frequency of about 300,000 MHz at a wavelength of about 1 millimeter to a frequency slightly below about 1,000 MHz at a wavelength of 30 centimeters. The present invention typically uses low frequency microwaves in this frequency range, preferably high power applications. In this preferred frequency range, there is a fundamental difference between microwave heating and classical heating methods such as infrared (eg cooking): Due to the greater penetration, microwaves are typically several centimeters deep While heating rapidly, infrared heating is probably superficial. Commercial microwave appliances such as cooking microwaves in the United States are available at standard frequencies of about 915 MHz and 2450 MHz, respectively. These frequencies are standard industrial frequency bands. In Europe, microwave frequencies of 2450 and 896 MHz are commonly used. However, under precisely calculated conditions, microwaves of other frequencies and wavelengths may be useful in achieving the objects and benefits of the present invention.
Microwave energy can be generated at various power levels depending on the desired application. In a conventional cooking microwave appliance (usually about 800 watts) with a power level of 600-1000 watts, the microwave is typically generated by a magnetron, but commercial equipment is usually about 1 kilowatt module. By adding a source, it is possible to generate electricity of several hundred kilowatts. The magnetron can generate a suitable high frequency pulse wave or continuous wave.
The application tool (or oven) is the necessary coupling means between the microwave power generator and the material to be heated. For the purposes of the present invention, any desired application device can be used, so long as it is adapted to effectively expose a portion of the tobacco crop to radiation. The applicator must be compatible with the microwave generator to optimize power transfer and avoid leakage of energy to the outside. Multimode cavities (microwave ovens), which can be sized larger than several times the wavelength if necessary, are useful for large samples. In order to ensure uniform heating inside the leaves, the application tool can be equipped with a moving plane such as a mode stirrer (a metal moving tool that continuously changes the electric field distribution) and a belt conveyor. The best results were obtained by exposure to microwave radiation with a single leaf thickness rather than bundled or stacked leaves.
In a preferred embodiment of the invention, the microwave conditions are from about 900 MHz to about 2500 MHz microwave frequency, more preferably about 915 MHz and about 2450 MHz, power levels from about 600 watts to 300 kilowatts, more preferably cooking appliances. For about 600 watts to about 1000 watts, and for commercial application multimode devices, about 2 to about 75 kilowatts, more preferably about 5 to about 50 kilowatts. The heating time is generally in the range of at least about 1 second, more typically from about 10 seconds to about 5 minutes. When processing single-thick leaves rather than bundled or stacked leaves at a power level of about 800-1000 watts, the heating time is preferably about 1 to 2.5 minutes. For example, the heating time for commercial scale applicators using high power levels in the range of 2-75 kilowatts is about 5 seconds to about 60 seconds for single-thick leaves rather than re-bunched or stacked leaves. Up to, and generally 50 kilowatts would be as short as 10-30 seconds. Of course, those skilled in the art will appreciate that the optimum microwave field density can be determined for any application device based on the volume of space, the power level used, and the amount of moisture in the leaves. Will. Generally speaking, if a higher power level is used, the time required to expose the mesenchyme to microwave radiation will be shorter.
However, the conditions described above are not absolute and provide an explanation of the invention, and those skilled in the art will be able to determine appropriate microwave conditions. The microwave radiation is applied to the leaves, or a part thereof, for a time sufficient to effectively dry the leaves, so as to be suitable for human consumption, without burning. The microwave radiation is preferably applied to the leaf or part thereof for a time and power level sufficient to reduce the moisture content to about 20% by weight, more preferably below 10% by weight.
FIG. 3 shows a partial perspective view of an embodiment of a commercial scale microwave applicator. In particular, the approximate dimensions of each space of the moving truck car frame 2 (not shown, but the front end is the right side of the figure) and the single-wall structure (which can be suitably constructed from 3003H14 aluminum) inside is approximately 4. Conveyed microwave oven 3 comprising 4 modular oven spaces 8 meters (16 ') wide x about 2.1 meters (84 ") x high about 1.2 meters (48") 1 shows a Microdry 300 kW microwave tobacco drying system 1. Each space has four doors, two on each side. The door is double interlocked to prevent accidental exposure to microwave energy.
FIG. 3 shows a plurality of (for example, twelve) rotary blade automatic cutting mechanisms 5 for removing the petiole from the leaves 4. The cutting blade may be a straight slab that is about 8.6 centimeters (3.4 inches) wide and descends into the center of a manually fed leaf. Appropriate protective equipment can be installed if desired to prevent operator hand insertion. FIG. 3 shows a petiotomy mechanism, but as described above, according to other aspects of the invention, all leaves can be used. Therefore, instead of the excision mechanism, a pair of rollers that squeeze moisture from the steam treatment vessel or the leaf can be employed in the apparatus.
Returning to FIG. 3, after the petiotomy operation, the cut leaves 6 are conveyed by the belt conveyor 7 to the main microwave oven 3 that accommodates four spaces. In one embodiment, the system has an oven that is about 24 meters (about 78 feet) long. At the introduction and interior of the oven, the conveyor system was set up so that the cut petals pass between a pair of belts and fall into a hopper (not shown) placed under the belts, Another plurality of, for example, six, variable speed polypropylene belts may be used. The belt then passes the cut tobacco leaves through one of two traps, one in each space designed to contain microwave energy, and then the principle of the invention described above Will carry each leaf to a selected space where it is subjected to microwave processing. After microwave processing, the conveyor transports the leaves out of the oven, through the space outlet, through the oven outlet trap, and then into the appropriate container where the leaves are taken for further processing.
An exhaust system including a suitable blower for air recirculation may be included in the system to remove air containing moisture from the space and oven (in FIG. 3, one is typically labeled as member 8). Moisture exhaust vents). Also, if desired, the interior of the oven outside the microwave space can be brought to a preferred constant temperature, for example, about 71-82 ° C. (160-180 ° F.), while the leaves are conveyed by conveyor. The temperature can be controlled by a convection heating source of circulating air installed at appropriate intervals so as to maintain. In the case of a mobile system used in the field as shown in FIG. 3, the required power can be supplied by a pair of ordinary diesel power generators 9, 10. Of course, the microwave drying system can also be operated in a fixed location with power from a normal power source if desired.
Each of the four spaces in the oven 3 of FIG. 3 receives microwave energy from a corresponding microwave dry IV-75 type microwave power source. Microwave energy enters each space via two splitters installed at the top of each space via a splitter. A mode stirrer is installed under each space inlet to assist in the distribution of microwave energy. Each microwave power supply is a complete cabinet that contains the components necessary to run a 75 kW magnetron. The control of the microwave power source is installed in the small room. The device is designed for unattended continuous operation in an industrial environment. Each microwave power generator may be located beside each space or at a remote location. However, at a distance of about 15 m (50 '), the transmission line loss would be about 2%. Each power generator provides adjustable microwave energy for industrial operation. The output power can be adjusted from 0 to about 75 kW at FCC's assigned 915 MHz frequency, and can be adjusted manually by the control knob on the control panel or remotely controlled by a 4-20 mA control signal from the process controller. It is controlled by a state control circuit. On the circuit, the power output is controlled from 0, but the frequency width is wide at a level of about 5 kW or less. Each space power generator is a DC power supply that operates an industrial magnetron, which is basically operated and protected by circuit functions designed for automatic and manual operation. The electrical function of the generator is monitored by a control panel instrument installed at the door of the compartment. Measurements are anode current, anode voltage, output power, filament current, electromagnetic current, and reflected power. The operation of the electro-mechanical interlock function is monitored by a defined lamp on the control panel. The chamber for each microwave power generator has a full width door to allow maximum access to the components. The magnetron and associated microwave components are housed in a built-in electromagnetic shielding shield. A magnetron and an electromagnet can be installed by the door. The system includes a circulatory and water load installed inside the chamber that acts as an isolator that protects the magnetron during high reflect power conditions. Microwave power generators use both forced air and water to cool components that generate heat. The magnetron and electromagnet are water cooled by a closed circuit demineralized water system. A separate water source and heat exchanger can be used to cool the water in this circuit. A separate water source also allows water to flow through the air heat exchanger in the compartment and cools the air in the compartment. A high pressure centrifugal blower cools the magnetron output window and the cathode structure. Water and chamber temperature are interlocked within the control power chain. Typical references for the microwave generator of the system herein are as follows:
Input power 95KVA, 440-480VAC, 3-phase, 60Hz
Output power 75kW at 915 ± 10MHz
Magnetron tube CTL, CWM 75 I
References for typical magnetron operation are as follows:
AC filament voltage 11.4V
Filament current 85A
DC anode voltage 17KV
Anode current 5.0A
DC electromagnet current 4.3A
80% efficiency
Furthermore, a typical microwave generator can employ a carbon steel container and has an output coupling (WR975 waveguide) at a suitable location at the top of the chamber.
In throughput tests, the microwave tobacco drying system, generally designed as described above, was effective in removing more than 80% of the leaf moisture content. In particular, in one measured sample, about 6.8 kg (15 pounds) of leaves with an assumed initial moisture content of 85% and a solids content of 15%, about one pound of leaf per hour, It passed through the microwave space at a rate of 82 kg (180 lbs). Leaf weight was measured after the space exit. The final weight was about 2.1 kg (4.6 pounds), or 31% of the initial weight. Thus, based on the initial assumed water content, approximately 1.07 kg (2.35 pounds) of water remains in the leaves, which corresponds to 18.5% of the initial water content.
As disclosed in FIG. 2, the microwave treatment of yellow tobacco according to the present invention preferably results in a dry golden tobacco product. The data presented herein show that tobacco dry in such dry form contains dramatically reduced carcinogenic nitrosamines, especially NNN and NNK, unlike standard processed tobacco. Prove that
Emission of electromagnetic waves in a concentrated form (ie, concentrated in the visible light range so that it can be distinguished from general exposure to sunlight or electrical light) with higher frequencies and shorter wavelengths than the microwave region described above By treating tobacco in such an energy form and in approximately the same time frame after harvest, as described above for the microwave embodiment, of the present invention-of TSNAs of tobacco products It has been found that it can be used to achieve reduction or substantial elimination. In other words, the general and preferred techniques and principles similar to those described above for microwave processing can also be applied when using such other energy sources; Treated with such radiation in the same time frame, leaves can be petiole removed prior to radiation, squeezed or steamed between rollers, and so on.
However, such other energy sources have been determined to significantly and preferably reduce or substantially eliminate or inhibit the formation of TSNAs, but any of the other tested to date The embodiment is also not as effective in drying leaves as the microwave technology described in detail. Thus, when using such another energy source, a further process combining the irradiation step with a subsequent oven drying or rotary drying step to complete the process of irradiating the irradiated tobacco leaves. It may be preferable to multiply it.
In particular, any electromagnetic radiation source with a higher frequency than the microwave region in the normal electromagnetic band, and accelerated particle beams such as electron beams, are the amount of TSNAs or tobacco that are untreated and to be reduced. It is believed to have the effect of significantly reducing, substantially removing and / or inhibiting formation of TSNAs when in an susceptible state with its formation. 10 microwaves¹¹Hz and 3x10^-3On a scale within the electromagnetic band, which is generally defined to include forms of electromagnetic radiation having a wavelength of meters, such energy sources are not limited and are approximately 10¹²To 10¹⁴Hz frequency and 3x10^-FourTo 3x10¹⁶Far infrared and infrared radiation with a wavelength of meters, about 10¹⁶To 10¹⁸Hz frequency and 3x10^-8To 3x10^-TenUV radiation, soft X-rays or lasers with a wavelength of^{twenty one}Including gamma radiation characterized by having a frequency above Hz and a corresponding wavelength.
As will be apparent to those skilled in the art, the greater the dose of radiation emitted by the energy source, the less time is required to apply the leaf to it to achieve the desired result. Typically, when using such high frequency radiation sources, radiation application times of no more than 1 minute, preferably no more than 30 seconds, more preferably no more than about 10 seconds are required. If defined otherwise, a radiation application time of at least about 1 second is preferred. However, as shown in the examples below, if desired, the rate of exposure can be controlled by overdosing the radiation dose. For example, 1 megarad of radiation instantaneously (as by an electron beam accelerator as revealed in Example 17 below) or at a predetermined exposure rate (as revealed in Example 19 below) (As exemplified by a sealed container gamma radiation test) where (10 kilogrey) of radiation was emitted at an exposure rate of about 0.8 megarad per hour. When using a high frequency radiation source, it is preferred to use a radiation dose that achieves at least a 50% reduction in TSNAs compared to an untreated sample. The specific radiation dose and exposure rate will depend on the specific equipment and type of radiation source applied, but as will be apparent to those skilled in the art, the tobacco sample is about 0.1 to about 10 megarads, more preferably It is generally preferred to apply radiation from about 0.5 to about 5 megarads, and more preferably from about 0.75 to about 1.5 megarads.
As illustrated in the examples below, the test was performed on various tobacco samples as examples of these additional radiation sources, such as an accelerated electron beam, CO₂This was done using laser and gamma radiation. In each case. Untreated irradiated tobacco samples were found to contain significantly reduced and / or substantially eliminated content of TSNA.
In yet another embodiment of the present invention, treatment of tobacco that is still susceptible in an air recirculating convection oven has also been shown to reduce TSNA, although leaf quality is also reduced. . Unlike conventional high temperature drying ovens, which are not effective in reducing TSNA content and reduce tobacco quality, at temperatures from about 38 ° C. to about 260 ° C. (about 100 ° to about 500 ° F.), at low temperatures Heating in an air recirculating convection oven at temperatures ranging from 1 hour to about 5 minutes also effectively reduces the content of TSNAs in susceptible tobacco as defined herein. Or prevented formation. Even more preferably, an oven that combines air recirculation convection heating and microwave radiation can reduce heating time while improving leaf quality. For example, when the convection oven is used alone, the leaf veins and petiole are not completely dry when the leaf blades are dry, so the leaf blade portion becomes too dry and dusted. Combining microwave treatment with recirculating convection oven heating can yield a more evenly dried product and improve leaf quality.
In another aspect, the present invention provides smoking, chewing, or otherwise smoking by providing tobacco products for consumption that have significantly reduced or substantially eliminated TSNAs. Relates to a method for reducing or substantially eliminating tobacco-specific nitrosamine content in the human or animal itself.
It is shown herein that subjecting untreated tobacco to microwave or other radiation energy is effective in providing tobacco with a surprisingly low nitrosamine content. These technologies are facilitated by stripping and disposing of one-third to one-half the length of tobacco leaves, especially when discarding the petiole and not employing moisture pressing or the steam treatment described above. it can. When the petiole is removed by this method, the obtained microwave-treated tobacco leaves do not require the use of a petiole remover since the unwanted portions of the petiole have already been removed. As a result, tobacco waste is reduced by 10% to 30%, eliminating the typical loss of tobacco products associated with petiole removal. The improved tobacco of the present invention is processed in a standard manner in any tobacco product, including cigarettes, cigars, chewing tobacco, tobacco chewing gum, tobacco troches, tobacco pouches, snuff, or tobacco flavors and food additives. It can be replaced with all or part of the smoked tobacco. For smoking purposes, the present invention provides a less unpleasant odor at standard nicotine content while maintaining good smoking characteristics and providing sufficient flavor. For the purposes of chewing tobacco, snuff, pouch and food addition, the tobacco of the present invention has a rich and pleasant aroma.
The invention will now be illustrated by reference to the following examples, which are not intended to limit the scope of the invention in any way.
Example 1
Virginia flue tobacco was harvested and the leaves were placed in a storage shed at about 38-43 ° C. (about 100-110 ° F.) to begin flue curing. Sample 1-3 was collected from the shed about 24-36 hours after harvesting after the leaves turned yellow. Sample 1 was a leaf blade sample that had a main vein and was hot dried in a convection air oven at about 400-500 ° C., which caused the leaf blade to brown. Sample 2 was a yellow leaf placed in a Goldstar model MA-1572M microwave oven (2450 MHz) and heated for about 2.5 minutes while rotating at a high power setting (1000 watts). Sample 3 was a yellow leaf used as an untreated control. Samples 4 and 5 were left in the storage shed at a high temperature of about 82 ° C. (about 180 ° F.), Sample 4 was dried outside the rack, and Sample 5 was dried inside the rack. Sample 6 is a treated brown leaf that has undergone standard flue processing.
Analysis was performed to determine the NNN, NAT, NAB and NNK content for each sample. In this and the following examples, “TSNA” represents the total of these four tobacco-specific nitrosamines. Sample preparation and extraction are typical methods for the analysis of TSNAs (eg, Burton et al., “Distribution of tobacco components in tobacco leaf tissue. 1. Tobacco-specific nitrosamines, nitrates, nitrites and alkaloids”, J. Am. Agric. Food Chem., Volume 40, No. 6, 1992), and individual TSNAs were linked to a Hewlett-Packard model 5890A gas chromatograph, Thermedics Inc. Quantified with a TEA model 543 thermal energy analyzer. The results are shown in Table 1 below. All data in each of the following tables is given in micrograms of nitrosamine per gram of sample (ie parts per million or μg / g):

Example 2
Virginia flue tobacco was collected. Sample 7 was a freshly cut, green leaf used as a control. Sample 8, on the other hand, was a multi-mode microwave applicator from MicroDry, Louisville, KY, operating at 2450 MHz at 2.5 kilowatts, and was a freshly cut green leaf irradiated with microwave radiation. . Samples 9-12 were obtained from brown tobacco with a standard flue treatment. Sample 9 was tobacco from molded cigarettes; Sample 10 was loose, cut tobacco for making cigarettes. Samples 11 and 12 were the same as Sample 9 (cigarette) and Sample 10 (rose), respectively, except that each was subjected to the same microwave conditions as Sample 8. The TSNA content was analyzed by the same method as in Example 1. The results are shown in Table 2 below:

Example 3
The following brands of cigarettes shown in Table 3 were randomly purchased from various retailers in Lexington, Kentucky and analyzed for TSNA using the method described in Example 1:

Example 4
Virginia flue tobacco was harvested and the leaves were placed in a storage shed at about 38-43 ° C (about 100-110 ° F) to begin flue processing. About 24-36 hours after harvesting, leaves turn yellow and leaves the shed, about 2.5 minutes while rotating at a high power setting (1000 watts) in a Goldstar model MA-1572M microwave oven (2450 MHz) Microwave processed. The leaves were effectively dried in this way and did not turn brown, but instead kept their bright yellow color. The leaves were cut and cigarettes were prepared. Samples 29-33 were taken from the batch labeled red full flavor, while samples 34-38 were taken from the batch labeled blue light. Samples 39-42 are cigarettes of the brand called Natural American Spirit purchased from a health food store. Samples 29-42 were analyzed for TSNA content using the method described in Example 1 and the results are shown in Table 4 below:

The STD in the tables herein is the standard deviation relative to the average of the samples shown.
Example 5
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. After the leaves turned yellow, the samples were taken from the drying room for about 24-36 hours after harvesting, and irradiated with microwaves for about 20 and about 30 seconds at an output level of about 6 kilowatts in the aforementioned MicroDry multimode applicator. 43-44. Samples 43 and 44 after microwave treatment were dry golden leaves. Samples 45-51 were prepared from dried brown leaves that had undergone a normal hot air drying process. Sample 45 was a control; samples 46 and 47 were heated in a convection oven preheated to about 400-500 ° F. for about 1 and about 3 minutes, respectively; and Waveguide applicator Model WR-975, a large multimode oven from MicroDry ( Samples 48 and 49 were irradiated with microwaves (915 MHz) at 50 kilowatts for about 10 and 40 seconds at an output setting of 0-75 KW, respectively. Samples 50 and 51 were chopped (reconstituted sheet) tobacco prepared from hot-air dried leaves. Sample 50 was irradiated with microwave at 50 kilowatts for about 1.5 minutes in a waveguide microwave oven, while sample 51 was heated in a convection oven preheated to about 400-500 ° F. for about 3 minutes. The TSNA content was measured for these samples using the method described in Example 1 and the results are shown in Table 5 below:

Example 6
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. Samples 52-55 are cigarettes prepared from yellowed tobacco removed from the drying chamber after approximately 24-36 hours and are configured for high power (1000 Watts) in a Goldstar microwave oven, Model MA-1572M (2450 MHz). And irradiated with microwaves for about 2 minutes. For comparison, samples 61 and 62 were cigarettes prepared from leaves that had undergone a normal hot-air drying process and not subjected to microwave treatment. Dried leaves were sample 56; dark yellow and not completely dried sample 57; dried leaf blades were sample 58 and dry midribs were samples 59 and 60. TSNA content was measured as in Example 1 and the results are shown in Table 6 below:

Example 7
Virginia full tobacco was harvested. Samples 63 and 66 were green and freshly chopped green tobacco. However, since more than one week had passed before the TSNA measurement was performed, the samples were air-dried somewhat. The remaining leaves were placed in a drying chamber at about 100-110 ° F. to begin the hot air drying process. After the leaves turned yellow, the sample 68 was taken out of the drying room for about 24-36 hours after harvesting, and irradiated with microwaves at 25 kilowatts for about 40 seconds in the aforementioned Waveguide multimode applicator.
Samples 64/65 (leaves) and 67/70 (reconstituted sheet or “chopped” tobacco) illustrate the effect of the present invention when dry tobacco is reconstituted with water and subjected to microwave irradiation. Samples 64 and 65 were leaf samples that had undergone a normal hot air drying process; sample 64 was treated with running water for about 5-10 seconds and returned with water. The leaves absorbed water significantly. Samples 64 and 65 were each then microwaved for about 40 seconds at 25 kilowatts with a Waveguide multimode applicator. Samples 67 and 70 were prepared as reconstituted sheet tobacco prepared from dried leaves. Sample 67 was reconstituted with water by adding water to absorb a significant amount and irradiated with microwaves under the conditions described in sample 64. Sample 70 was not irradiated with microwaves. Another sample of dried leaves was sample 69, 71 and 72 and was used as a control. TSNA content was measured as in Example 1 and the results are shown in Table 7 below:

Example 8
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. After the leaves turned yellow, samples 73 were taken from the drying room for about 24-36 hours post-harvest processing and microwaved in Goldstar Model MA-1572M for about 2 minutes at high power setting. Samples 74-76 were dried with hot air in the usual manner. Sample 74 is a dry control. Example 7 (Sample 64) was reconstituted with water and microwaved for about 20 seconds (Sample 75) and about 40 seconds (Sample 76) at a power level of about 6 kilowatts in a MicroDry applicator (2450 MHz), respectively. Samples 75 and 76 were used. Samples 77-79 were reconstituted sheet tobacco prepared from hot air dried leaves. Sample 77 was the control, and samples 78 and 79 were reconstituted with water as in Example 7 (Sample 67). Samples 78 and 79 were each microwaved for about 30 seconds with a MicroDry applicator; sample 78 was left on the bottom of the oven, but sample 79 was several inches tall with the sheet sample placed on a styrohome container In position, this allowed more uniform heating. TSNA content was measured as in Example 1 and the results are shown in Table 8 below:

Example 9
Samples 80-81 were Redman chewing tobacco purchased at a retail store. The control was sample 80, and sample 81 was microwave treated in Goldstar Model MA-1572M at high power setting for about 1-2 minutes. Samples 82-83 were Skoal snuff purchased at a retail store. The control was sample 82, and the sample 83 was subjected to microwave treatment in the same manner as sample 81. TSNA content was measured and the results are shown in Table 9 below:

Example 10
To examine whether TSNA accumulates even after microwave treatment of yellowed tobacco according to the present invention, an additional sample of cigarettes examined in Example 4 (referred to as -A), samples 29, 35, and For 39 (control), the TSNA content was re-measured as described in Example 4 after 7 months had passed since the TSNA content was first measured. The results are shown in Table 10 below:

Example 11
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. After the leaves turned yellow, the post-harvest treatments were removed from the drying room for about 24-36 hours and irradiated with microwaves in a Goldstar Model MA-1572M microwave oven at high power setting for about 2 to 2.5 minutes. Each leaf was golden and effectively dried. Several samples, termed “milled”, were then ground into powders, which would be useful, for example, as gums, medicinal drops or food additives. After 6 months from the time when the leaves were microwaved, the TSNA content of the following samples was measured using the method described in Example 1. The results are shown in Table 11 below:

Example 12
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. Samples 104 and 105 were leaf samples that had undergone a normal hot air drying process and were not subjected to microwave treatment. The dried middle rib was designated as sample 104 and the dried leaf blade was designated as sample 105. After the leaves turned yellow, the yellowed tobacco taken out of the drying room for about 24-36 hours after harvesting was used as sample 106. After removal from the drying chamber, the leaves were irradiated with microwaves in a Goldstar Model MA-1572M microwave oven at a high power setting for about 2 to 2.5 minutes. Each leaf was golden and effectively dried. Some of the dried leaves were further processed by conventional methods of preparing tobacco extracts and this was used as sample 107 for analysis. The TSNA content of Samples 104-107 was measured using the method described in Example 1. The results are shown in Table 12 below:

Example 13
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. Samples 108 and 109 were leaf samples that had undergone a normal hot air drying process. The dried leaf blade was designated as sample 108, and the dried middle rib was designated as sample 109. Samples 110 and 111 were yellowed tobacco removed from the drying room for about 24-36 hours post-harvest treatment after the leaves turned yellow. After removal from the drying chamber, samples 110 and 111 were placed in an air circulating convection oven, Sharp Carousel Convection / Microwave Model No. Heated with R-9H84B. Sample 110 was rapidly heated at about 300 ° F. for 5-10 minutes. Sample 111 was obtained by starting from about 100 ° F., gradually increasing to about 150 ° F. over a period longer than 10 minutes, and further gradually heating at a low temperature for a total heating time of 20 minutes. The TSNA content of Sample 108-111 was measured using the method described in Example 1. The results are shown in Table 13 below:

Although convection oven heating has been shown to reduce TSNA levels, tobacco quality was inferior to that obtained by microwave treatment according to the preferred embodiment of the present invention. Furthermore, the heating time is necessarily longer than when using microwave treatment or other forms of high frequency irradiation. Specifically, convection heating was unable to fix the color to the desired golden color and the leaf blades were too dry and therefore tended to be friable while the veins and midribs were completely Not dried. In contrast, in accordance with the most preferred embodiment of the present invention, the microwave treated leaves are effectively dried and retain the golden color after treatment and for further processing, especially for cigarettes. It remained supple and flexible. In the convection oven treated sample, the dried leaf blades were easily broken into powder and small tobacco pieces.
Example 14
After Kentoky burley tobacco was harvested and the leaves turned yellow, the leaves were treated as follows for about 24-36 hours post-harvest treatment. Samples 112-117 were leaf samples from this round of raw material treated as follows. Sample 112 was subjected to microwave treatment under almost the same conditions as sample 106 in Example 12. The leaves were golden and effectively dry. Samples 113 and 114 and 117 were heated in the same air circulation convection oven as described in Example 13. Sample 113 was heated under almost the same conditions as sample 110, sample 114 was heated under almost the same conditions as sample 111, and sample 117 was heated at about 350 ° F. for about 20 minutes. The quality of samples 113, 114 and 117 was similar to the quality of samples 110 and 111 described in Example 13. Sample 115 using the Sharp Carousel Convection / Microwave oven described in Example 13 using a combination of microwave (30%) / convection (300 ° C.) functions and heating until the leaves are effectively dried to a golden color. And 116. The TSNA content of Samples 112-117 was measured using the method described in Example 1. The results are shown in Table 14 below:

Example 15
Virginia flue tobacco was harvested and the leaves were placed in a drying room at about 100-110 ° F. to begin the hot air drying process. Samples 118-120 were removed from the drying chamber after the leaves began to turn yellow, and immediately afterwards in the convection kitchen microwave oven for about 2 to 2.5 minutes, effectively with a golden color without burning or burning the leaves. It was a leaf sample that was irradiated with microwaves until dry. Samples 121-123 were Kentoky burley tobacco samples that were harvested and first yellowed and then treated as follows. Sample 121 was placed in a convection steam rotary dryer commonly used in the tobacco industry until the leaves turned brown at a temperature of about 200 ° F. and somewhat dried. Microwaved in the cited Goldstar microwave oven at high power for about 2 minutes, put back in water and slightly browned leaves, which are said to intensify the aroma, and put in a tumble dryer Sample 122 was obtained. Sample 123 was treated in the same manner as sample 122 except that it was microwaved for 1 minute and not returned to water before being placed in the tumble dryer. TSNA content was measured as in Example 1 and the results are shown in Table 15 below:

Example 16
After North Carolina burley tobacco was harvested and the leaves began to turn yellow, the post-harvest treatment, about 2-3 days, treated the leaves as follows. A sample of a leaf that was irradiated with microwaves for about 2 minutes at a high output setting in a Goldstar microwave oven of the same type as described above was designated as sample 118. After microwave treatment the leaves were golden and effectively dried. The TSNA content was measured using the method described in Example 1. The results are shown in Table 16 below:

Example 17
This example illustrates the effect of using electron beam irradiation to reduce TSNA content or substantially inhibit its synthesis in a yellowed tobacco sample. Harvest burley tobacco from North Carolina. Samples 119-122 were air-dried leaf samples by hanging outdoors in the normal manner until the leaf was effectively dried and brown. Sample 119 was not treated for control. Radiation Dynamics, Inc. of Edgewood, N.E. Y. Samples 120 and 121 were obtained by performing electron beam irradiation on a conveyer belt with an exposure intensity of 1 megaderad using a Dynamitron Electron Beam Accelerator manufactured by Panasonic. Sample 122 was irradiated with microwaves for about 2 minutes at a high power setting in a Goldstar microwave oven. The tip of the leaf of the burley tobacco after starting to turn yellow was collected as a sample 123. A petiole portion taken from the same plant as sample 123 was taken as sample 124, which was still somewhat green. Samples 125 and 126 were the entire leaves of the Burley sample at the yellowing stage. Using the above-mentioned Dynamitron for each of the samples 123 to 126, electron beam irradiation was performed in the same manner as described above with the same method and the same exposure intensity as those of the samples 120 and 121. The sample was measured for TSNA content according to the method described in Example 1 and the results are shown in Table 17 below:

The above data show that electron beam irradiation is effective in inhibiting the formation of a substantial amount of tobacco-specific nitrosamines in yellowed tobacco studied, but the application was applied to the leaves at the same stage of post-harvest treatment. Leaves were not effectively dried as when microwave irradiation was performed as described in other examples. Thus, commercial applications of electron beam irradiation methods may require additional drying steps such as passing irradiated leaves through a convection drying oven to facilitate the drying process.
Example 18
This example illustrates that a high energy beam emitted from a laser to achieve the low TSNA goal of the present invention is also effective. Luxar Corp. CO made₂A laser, Model LX-20SP, was used to irradiate yellowed Virginia full tobacco leaves about 2-3 days post-harvest treatment. NovaScan handpiece was used with the superpulse E program which determines the application speed in patterns per second. An E10 setting was used that irradiates 10 patterns per second. Eight subsamples of leaves, T-1 to T-8, were irradiated according to the following method:

At 2 Watts, about 120 mJ of energy was irradiated in each scan or pass, while at 4 Watts, about 240 mJ was irradiated in each such scan.
Subsamples T-1 to T-4 were mixed and combined to give leaf sample 127, and TSNA content was evaluated in the same manner as described in Example 1. Subsamples T-5 to T-8 were similarly mixed and combined together to form leaf sample 128, and TSNA content was similarly evaluated. The results are shown in Table 18 below:

CO as in the sample described in Example 17₂Laser-irradiated samples have a low TSNA content but are not as effectively dried as microwave treated samples, and therefore additional drying steps could be used to accelerate the drying process. It was. In addition, CO₂There was no apparent effect on TSNA content, 6 of 8 subsamples turned somewhat brown after laser irradiation and before TSNA measurement.
Example 19
This example illustrates that gamma radiation is also effective in inhibiting significant amounts of TSNA formation in yellowed tobacco. In about 2-3 days after the harvest, Virginia full tobacco was collected immediately after the leaves began to turn yellow. Samples 129-132 were each taken from the leaf blade portion of the yellowed leaves and in a shielded container with 10 kGrey (1 megarad) gamma radiation, 8 kGrey (0.8 megagard) exposure intensity per hour for a total exposure time of about 75 minutes, Was irradiated. The irradiated samples were subsequently evaluated for TSNA content in the same manner as described above, and the results are shown in Table 19 below:

It will be apparent to those skilled in the art that many changes and modifications can be made in the preferred embodiment without departing from the spirit and scope of the claimed invention. Accordingly, the foregoing description is intended to be illustrative only and should not be considered for the purpose of limitation.

Claims (41)

(I) (a) removing the shaft from the tobacco leaf, (b) squeezing the tobacco leaf to remove excess moisture, or (c) subjecting the tobacco leaf to steam treatment, and ( ii) While the harvested tobacco plant is not cured and is placed in a state where the amount of nitrosamines can be reduced or the formation of nitrosamines can be prevented, Subjecting the harvested tobacco plant to microwave radiation for a time sufficient to reduce the amount or substantially inhibit its formation, said subjecting the microwave radiation to initiation of leaf yellowing After and before the substantial accumulation of tobacco-specific nitrosamines in the leaves occurs, the leaves are placed in a single layer thickness without being stacked or stacked. It is carried out on the tobacco leaf,
A method for reducing or inhibiting the amount of nitrosamines in harvested tobacco plants. 2. The method of claim 1, wherein step (i) is step (b) or (c) and the tobacco leaf comprises an axis. Enough to substantially inhibit the formation of at least one nitrosamine while the harvested tobacco plant is yellow without being treated to be cured and capable of preventing the formation of nitrosamine Laying tobacco plants on radiation that has a higher frequency than the microwave region of the normal electromagnetic spectrum for a long time,
A method for substantially inhibiting the formation of nitrosamines in harvested tobacco plants. 4. The method of claim 3, wherein the exposure to radiation is performed on the tobacco leaf before substantial accumulation of tobacco-specific nitrosamines in the tobacco leaf occurs. 4. The method of claim 3, wherein the radiation is applied before plant cell integrity is substantially compromised. 4. The method of claim 3, wherein the tobacco is a flue tobacco and subjecting to the radiation occurs within about 24 hours to about 72 hours after harvest. 4. The method of claim 3, wherein the radiation is applied to the plant at a predetermined intensity level for at least about 1 second. 4. The method of claim 3, wherein said radiation is used to inhibit normal accumulation of at least one tobacco-specific nitrosamine in the leaf. The at least one tobacco-specific nitrosamine is N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrosoanatabine and N'-nitroso 9. The method of claim 8, wherein the method is selected from the group consisting of anabasine. 5. The method according to claim 4, wherein the irradiation is performed on tobacco leaves arranged in a single layer thickness without stacking or stacking the leaves. Prior to being subjected to the radiation, (a) removing the shaft from the tobacco leaf, (b) squeezing the tobacco leaf to remove excess moisture, or (c) steaming the tobacco leaf. The method according to claim 10, further comprising the step of: providing. 4. The method of claim 3, further comprising drying the tobacco plant after performing the step of radiation emission. 4. The method according to claim 3, wherein the radiation is generated by a laser beam. 4. The method according to claim 3, wherein the radiation is an electron beam generated by an electron accelerator. 4. A method according to claim 3, wherein the radiation is gamma radiation. While the tobacco leaf is not cured and is placed in a state where the amount of tobacco-specific nitrosamines can be reduced or the formation of tobacco-specific nitrosamines can be prevented, at least one in the leaves Subjecting the tobacco leaves to radiation having a frequency higher than the microwave region of the normal electromagnetic spectrum for a time sufficient to reduce or substantially inhibit the formation of two tobacco-specific nitrosamines; And said tobacco product comprising a microwave irradiated leaf and selected from the group consisting of cigarette, cigar, chewing tobacco, snuff and tobacco-containing gum, and lozenge Forming,
A method for producing a tobacco product, comprising: 17. The method of claim 16, wherein the leaves are subjected to the radiation after the onset of leaf yellowing and before substantial accumulation of tobacco-specific nitrosamines in the leaves occurs. 18. A tobacco product produced by the method of any one of claims 1 to 17, comprising a cured non-green Burley tobacco or a yellow Burley tobacco suitable for human consumption, wherein the tobacco product is expanded. Substantially free of the organic liquid used to extract the organic material and N′-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N The tobacco product, wherein the total content of '-nitrosoanatabine and N'-nitrosoanavacin is 0.05 µg / g or less. 19. A tobacco product according to claim 18, wherein the tobacco suitable for human consumption is a cured yellow tobacco. 19. A tobacco product according to claim 18, selected from the group consisting of cigarettes, cigars, chewing tobacco, snuff and tobacco-containing gums, and bits. 18. A tobacco product made by the method of any one of claims 1 to 17, comprising a cured non-green Burley tobacco or yellow Burley tobacco suitable for human consumption, comprising: And the sum of N′-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N′-nitrosoanatabine and N′-nitrosoanabasin The said tobacco product whose content is 0.05 microgram / g or less. 24. The tobacco product of claim 21, wherein the tobacco suitable for human consumption is a cured yellow tobacco. 23. The tobacco product of claim 21, selected from the group consisting of cigarettes, cigars, chewing tobacco, snuff and tobacco-containing gums, and bits. 18. A tobacco product made by the method of any one of claims 1 to 17, comprising a cured non-green Burley tobacco or yellow Burley tobacco suitable for human consumption, wherein the tobacco product is expanded. Is substantially free of organic liquid used to extract the organic material, and the content of 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone is 0.002 μg / g or less The tobacco product. 25. The tobacco product of claim 24, wherein the content of 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone is 0.001 μg / g or less. 25. The tobacco product of claim 24, wherein the tobacco suitable for human consumption is a cured yellow tobacco. 18. A tobacco product made by the method of any one of claims 1 to 17, comprising a cured non-green Burley tobacco or yellow Burley tobacco suitable for human consumption, comprising: And the tobacco product has a 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone content of 0.002 μg / g or less. 28. The tobacco product of claim 27, wherein the content of 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone is 0.001 μg / g or less. 28. The tobacco product of claim 27, wherein the tobacco suitable for human consumption is a cured yellow tobacco. 18. A tobacco product made by the method of any one of claims 1 to 17, comprising a cured non-green US Burley tobacco suitable for human consumption or a yellow US Burley tobacco. Substantially free of organic liquid used to extract the swollen organic material, and N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone The tobacco product, wherein the combined content of N'-nitrosoanatabine and N'-nitrosoanavacine is less than 0.2 μg / g. 32. The tobacco product of claim 30, wherein the total content is about 0.15 μg / g or less. 32. The tobacco product of claim 31, wherein the total content is about 0.1 μg / g or less. 33. The tobacco product of claim 32, wherein the total content is about 0.05 μg / g or less. 32. The tobacco product of claim 30, wherein the tobacco suitable for human consumption is a cured yellow tobacco. 32. The tobacco product of claim 30, selected from the group consisting of cigarettes, cigars, chewing tobacco, snuff and tobacco-containing gums, and bits. 18. A tobacco product made by the method of any one of claims 1 to 17, comprising a cured non-green US Burley tobacco or yellow US Burley tobacco suitable for human consumption, Leaf shape, and N'-nitrosonornicotine, 4- (N-nitrosomethylamino) -1- (3-pyridyl) -1-butanone, N'-nitrosoanatabine and N'-nitrosoanabasin Said tobacco product having a total content of less than 0.2 μg / g. 38. The tobacco product of claim 36, wherein the total content is about 0.15 μg / g or less. 38. The tobacco product of claim 37, wherein the total content is about 0.1 μg / g or less. 40. The tobacco product of claim 38, wherein the total content is about 0.05 μg / g or less. 38. The tobacco product of claim 36, wherein the tobacco suitable for human consumption is a cured yellow tobacco. 38. The tobacco product of claim 36, selected from the group consisting of cigarettes, cigars, chewing tobacco, snuff and tobacco-containing gums, and bits.

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