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 - 15 . (canceled) 
     
     
         16 . A method of reducing an amount of matrix-bound NNK in cured tobacco plant material, comprising the steps of:
 (a) providing cured tobacco plant material;   (b) treating the cured plant material to reduce particle size;   (c) mechanically separating lignified tissue from non-lignified tissue in the treated cured tobacco plant material by size; and   (d) obtaining the mechanically separated treated cured tobacco plant material in which an 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).   
     
     
         17 . The method according to  claim 16 , wherein following step (a) there is a further step of measuring the amount of at least matrix-bound NNK. 
     
     
         18 . The method of  claim 16  wherein further comprises a first step of measuring the amount of at least matrix-bound NNK following step (a) and further comprises a second step of measuring the amount of at least matrix-bound NNK following step (b). 
     
     
         19 . The method of  claim 16  wherein mechanically separating lignified tissue from non-lignified tissue in step (c) comprises obtaining particles having an average size greater than about 0.5 millimetres. 
     
     
         20 . A method of reducing formation of matrix-bound NNK during curing of tobacco plant material comprising reducing an amount of lignin therein prior to curing, the method comprising the steps of:
 (a) providing uncured tobacco plant material;   (b) treating the uncured plant material to reduce particle size;   (c) mechanically separating lignified tissue from non-lignified tissue in the treated uncured tobacco plant material by size;   (d) curing the mechanically separated lignified tissue obtained from step (c)and   (e) obtaining the cured tobacco plant material from step (d) 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.   
     
     
         21 . The method according to  claim 20 , further comprising a first step of measuring the amount of at least matrix-bound NNK following step (a), and optionally, further comprise a second step of measuring the amount of at least matrix-bound NNK following step (b), and optionally, further comprising a third step of measuring the amount of at least matrix-bound NNK following step (c). 
     
     
         22 . The method of  claim 21 , wherein following step (c) or step (d) said method comprises the further step of comparing the level of at least matrix-bound NNK measured foin the first step with the level of at least matrix-bound NNK measured in the second and/or third steps, wherein a reduction in the amount of matrix-bound NNK in the tobacco material measured in second or third steps as compared to the amount of matrix-bound NNK measured in the first step is indicative that the amount of matrix-bound NNK in the tobacco material is reduced. 
     
     
         23 . The method according to  claim 20 , wherein the tobacco plant material is treated to expand non-lignified plant tissue, and/or 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 tobacco plant material; and/or   wherein the tobacco plant material provided in step (a) comprises plant midribs or plant stems or plant stalks or a combination of two or more thereof.   
     
     
         24 . The method of  claim 20 , wherein the amount of matrix-bound NNK in the cured tobacco plant material obtained in step (e) is about 3500 ng/g or less. 
     
     
         25 . A method for producing reconstituted tobacco comprising the steps of:
 (i) performing the method according to  claim 16 ;   (ii) manufacturing the tobacco material obtained in step (i) into reconstituted tobacco; and   (iii) incorporating the reconstituted tobacco into a tobacco product.   
     
     
         26 . A method for preparing tobacco for use as a tobacco cut filler comprising the steps of:
 (i) performing the method according to  claim 16 ; and   (ii) rolling and cutting the tobacco material for use as a tobacco cut filler.   
     
     
         27 . A method for blending tobacco in which at least two different types of tobacco are blended so as to form a tobacco blend, the method comprising the steps of:
 (i) providing a first cured tobacco plant material and reducing the amount of lignin therein by mechanically separating lignified tissue from non-lignified tissue according to the method of  claim 16 ;   (ii) 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 (i), and optionally measuring the total and/or matrix-bound NNK content in the second cured tobacco plant material;   (iii) blending together the first and second cured tobacco plant materials from steps (i) and (ii) and optionally measuring the total and/or matrix-bound NNK content in the blended tobacco plant material; and   (iv) 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 (ii),   optionally wherein step (i) is performed after step (ii).