Method of manufacturing reconstituted tobacco material and apparatus

Abstract

A reconstituted tobacco material is manufactured by extracting a natural tobacco material with an extracting solvent to obtain an extraction residue and a tobacco extracted liquid containing desired components and undesired components including tobacco-specific nitrosamines, subjecting the tobacco extracted liquid to a fractionating treatment by means of a reverse osmosis membrane to obtain a membrane impermeable fraction containing the desired components and depleted in the undesired components and a membrane permeable fraction depleted in the desired components and enriched in the undesired components, controlling the tobacco extracted liquid during the fractionating treatment to have a temperature suitable for the fractionating treatment, removing precipitates, which are precipitated in the tobacco extracted liquid during the fractionating treatment, from the tobacco extracted liquid, preparing a reconstituted tobacco web containing the extraction residue, and adding the membrane impermeable fraction to the reconstituted tobacco web.

What is claimed is:  
     
         1 . A method of manufacturing a reconstituted tobacco material, comprising:
 (a) extracting a natural tobacco material with an extracting solvent to obtain an extraction residue and a tobacco extracted liquid containing desired components and undesired components including tobacco-specific nitrosamines;   (b) subjecting the tobacco extracted liquid to a fractionating treatment by means of a reverse osmosis membrane to obtain a membrane impermeable fraction containing the desired components and depleted in the undesired components and a membrane permeable fraction depleted in the desired components and enriched in the undesired components;   (c) controlling the tobacco extracted liquid during the fractionating treatment to have a temperature suitable for the fractionating treatment;   (d) removing precipitates, which are precipitated in the tobacco extracted liquid during the fractionating treatment, from the tobacco extracted liquid;   (e) preparing a reconstituted tobacco web containing the extraction residue; and   (f) adding the membrane impermeable fraction to the reconstituted tobacco web.   
     
     
         2 . The method according to  claim 1 , wherein in tobacco extracted liquid is controlled to have a temperature within a range of 40 to 80° C. in the step (c). 
     
     
         3 . The method according to  claim 1 , wherein the step (b) comprises:
 repeatedly performing the fractionating treatment to obtain a concentrated membrane impermeable fraction, and   repeating a cycle of consisting of addition of process water to the concentrated membrane impermeable fraction and the fractionating treatment of the membrane impermeable fraction supplied with the process water.   
     
     
         4 . The method according to  claim 3 , wherein the cycle is repeated until a membrane impermeable fraction, from which the tobacco-specific nitrosamines contained in the tobacco extracted liquid obtained in the step (a) is removed by 60 wt % or more of its initial amount, is obtained. 
     
     
         5 . The method according to  claim 1 , wherein the step (c) is performed by using a filter having a pore size of 3 μm or less. 
     
     
         6 . The method according to  claim 3 , wherein the process water is obtained by removing bicarbonate ions from hard water containing bicarbonate ions. 
     
     
         7 . A fractionating apparatus for separating desired components from tobacco-specific nitrosamine-including undesired components in a tobacco extracted liquid, comprising:
 a process vessel which contains the tobacco extracted liquid;   a fractionating device comprising a reverse osmosis membrane by which the tobacco extracted liquid is fractionated into a membrane impermeable fraction containing the desired components and depleted in the undesired components and a membrane permeable fraction depleted in the desired components and enriched in the undesired components;   a pump which feeds the tobacco extracted liquid to the fractionating device under pressure;   a filter for removing precipitates such as protein which are precipitated in the tobacco extracted liquid during the fractionating treatment; and   a temperature controlling device which controls the tobacco extracted liquid to have a temperature suitable for the fractionating treatment during the fractionating treatment.   
     
     
         8 . The apparatus according to  claim 7 , wherein the temperature controlling device controls the tobacco extracted liquid to have a temperature within a range of 40 to 80° C. 
     
     
         9 . The apparatus according to  claim 7 , wherein the temperature controlling device is constituted of a heat exchanger. 
     
     
         10 . The apparatus according to  claim 7 , further comprising:
 an ultrafiltration device which comprises ultrafiltration membrane for removing bicarbonate ions from hard water containing bicarbonate ions, and is configured to provide bicarbonate ion-removed water as process water.