Methods for reducing matrix-bound nicotine-derived nitrosamine ketone in tobacco plant material

Abstract

A method of reducing the amount of matrix-bound NNK in cured tobacco plant material is provided comprising reducing the amount of lignin in the cured tobacco plant material. A further method of reducing the formation of matrix-bound NNK during the curing of tobacco plant material is described comprising reducing the amount of lignin therein prior to curing.

1 . A method of reducing the amount of matrix-bound NNK in cured tobacco plant material comprising separating lignified tissue from non-lignified tissue, wherein the amount of lignin is reduced mechanically. 
     
     
         2 . The method according to  claim 1 , comprising the steps of:
 (a) providing cured tobacco plant material;   (b) separating lignified from non-lignified tissue in the cured tobacco plant material; and   (c) obtaining cured tobacco plant material in which the amount of lignin is reduced and the amount of matrix-bound NNK is reduced as compared to the cured tobacco plant material provided in step (a).   
     
     
         3 . The method according to  claim 2 , wherein following step (a) there is a further step of measuring the amount of at least matrix-bound NNK, and optionally, wherein following step (b) there is a further step of measuring the amount of at least matrix-bound NNK. 
     
     
         4 . The method according to  claim 3 , wherein said method comprises the further step (d) of comparing the level of at least matrix-bound NNK measured following step (a) with the level of matrix-bound NNK measured following step (b), wherein a reduction in the amount of matrix-bound NNK in the tobacco material obtained in step (b) as compared to the tobacco material provided in step (a) is indicative that the amount of matrix-bound NNK in the tobacco material is reduced. 
     
     
         5 . A method of reducing the formation of matrix-bound NNK during curing of tobacco plant material comprising reducing the amount of lignin therein prior to curing, comprising the steps of:
 (a) providing uncured tobacco plant material;   (b) mechanically separating lignified from non-lignified tissue in the uncured tobacco plant material prior to curing;   (c) curing the tobacco plant material provided in step (b); and   (d) obtaining cured tobacco plant material in which the amount of matrix-bound NNK is reduced as compared to a control in which the amount of lignin has not been reduced.   
     
     
         6 . The method according to  claim 5 , wherein following step (a) there is a further step of measuring the amount of at least matrix-bound NNK, and optionally, wherein following step (b) there is a further step of measuring the amount of at least matrix-bound NNK and optionally, wherein following step (c) there is a further step of measuring the amount of at least matrix-bound NNK, preferably,
 wherein following step (c) or step (d) said method comprises the further step of comparing the level of at least matrix-bound NNK measured following step (a) with the level of at least matrix-bound NNK measured following step (b) and/or step (c), wherein a reduction in the amount of matrix-bound NNK in the tobacco material obtained in step (b) or step (c) as compared to the tobacco material provided in step (a) is indicative that the amount of matrix-bound NNK in the tobacco material is reduced.   
     
     
         7 . The method according to  claim 1 , wherein the tobacco plant material is treated to expand non-lignified plant tissue, preferably, wherein the amount of lignin is reduced by separating the expanded and non-expanded plant tissue based on their different densities and/or their different strengths and/or their different particle sizes and/or
 wherein the amount of lignin is reduced by removing at least the vascular bundle or xylem or lignified sclerenchymatic tissue or a combination of two or more thereof from the plant material; and/or   wherein the plant material provided in step (a) comprises or consists or consists essentially of plant midribs or plant stems or plant stalks or a combination of two or more thereof.   
     
     
         8 . Tobacco plant material obtained or obtainable by the method according to  claim 1 . 
     
     
         9 . A method for manufacturing a tobacco product having reduced levels of matrix-bound NNK, comprising:
 mechanically separating lignified tissue from non-lignified tissue in tobacco to reduce lignin as compared to control tobacco plant material,   forming the tobacco product from the non-lignified tissue,   wherein said levels of matrix-bound NNK are reduced as compared to the control.   
     
     
         10 . A method for producing reconstituted tobacco comprising the steps of:
 (a) performing the method according to  claim 1 ;   (b) manufacturing the tobacco material obtained in step (a) into reconstituted tobacco; and   (c) optionally incorporating the reconstituted tobacco into a tobacco product.   
     
     
         11 . Reconstituted tobacco obtained or obtainable by the method of  claim 10 . 
     
     
         12 . A method for preparing tobacco for use as a tobacco cut filler comprising the steps of:
 (a) performing the method according to  claim 1 ; and   (b) rolling and cutting the tobacco material for use as a tobacco cut filler.   
     
     
         13 . Cured tobacco plant material containing a reduced level of lignin as compared to control tobacco plant material in which the amount of lignin has not been reduced, wherein the amount of lignin in the cured tobacco plant material has been reduced by mechanically separating lignified tissue from non-lignified tissue, and wherein the amount of matrix-bound NNK is about 3500 ng/g or less, preferably,
 wherein the amount of free NNK is less than about 330 ng/g, optionally wherein the NNN content is less than about 1700 ng/g and optionally wherein the nicotine content is less than about 2610 μg/g; and/or   wherein the cured tobacco plant material comprises, consists of consists essentially of plant cortex—such as outer plant cortex; and/or   wherein vascular bundle or xylem or lignified sclerenchymatic tissue or a combination thereof is substantially absent from the cured plant tissue.   
     
     
         14 . A tobacco product or a reconstituted tobacco product comprising, consisting or consisting essentially of the tobacco plant material according to  claim 8 . 
     
     
         15 . A method for blending tobacco in which at least two different types of tobacco are blended so as to form a tobacco blend comprising the steps of:
 (a) providing a first cured tobacco plant material and reducing the amount of lignin therein by mechanically separating lignified tissue from non-lignified tissue;   (b) measuring the total and/or matrix-bound NNK content of the first cured tobacco plant material and selecting cured tobacco plant material in which the total and/or matrix-bound NNK content is reduced as compared to the first cured tobacco plant material provided in step (a);   (c) providing a second cured tobacco plant material which has a higher total and/or matrix-bound NNK content than the total and/or matrix-bound NNK of the first cured tobacco plant material obtained in step (b), and optionally measuring the total and/or matrix-bound NNK content in the second cured tobacco plant material;   (d) blending together the first and second cured tobacco plant materials from steps (b) and (c) and optionally measuring the total and/or matrix-bound NNK content in the blended tobacco plant material; and   (e) obtaining a blended tobacco plant material in which the total and/or matrix-bound NNK content of the blended tobacco plant material is lower than the second cured tobacco plant material provided in step (c),   optionally wherein steps (a) and (b) are performed after step (c).   
     
     
         16 . A tobacco product or a reconstituted tobacco product comprising, consisting or consisting essentially of the tobacco plant material according to  claim 13 .