Method of producing expanded tobacco stems

Abstract

A method of producing expanded tobacco stems for tobacco cut filler comprises the steps of: providing rolled tobacco stems having a rolled thickness of 0.1 to 0.5 mm; conditioning the rolled stems to increase the moisture content; cutting the conditioned tobacco stems; impregnating the cut tobacco stems with liquid carbon dioxide; heating the impregnated stems to bring about expansion; and re-conditioning the stems after heating to increase the moisture content. The rolled tobacco stems may be combined with tobacco lamina prior to the treatment steps.

1 . A method of producing expanded tobacco stems for tobacco cut filler, the method comprising the steps of:
 providing rolled tobacco stems having a rolled thickness of 0.1 to 0.5 mm;   conditioning the rolled stems;   cutting the conditioned tobacco stems;   impregnating the cut tobacco stems with liquid carbon dioxide;   heating the impregnated stems to bring about expansion; and   re-conditioning the stems after heating.   
     
     
         2 . A method according to  claim 1  wherein the rolled tobacco stems are combined with tobacco lamina prior to the conditioning step such that the subsequent steps are carried out on the combined tobacco stems and lamina. 
     
     
         3 . A method according to  claim 1  wherein during the conditioning step the moisture content of the tobacco stems is increased to at least 12% oven volatiles (o.v.). 
     
     
         4 . A method according to  claim 1  wherein during the re-conditioning step the moisture content of the tobacco stems is increased to at least 10% o.v. 
     
     
         5 . A method according to  claim 1  wherein each of the conditioning and re-conditioning steps comprises contacting the tobacco with steam, water or a mixture of steam and water. 
     
     
         6 . A method according to  claim 1  wherein the impregnation of the tobacco stems with liquid carbon dioxide is carried out under a vacuum. 
     
     
         7 . A method according to  claim 1  wherein during the heating step the tobacco stems are heated in a stream of hot gas at a temperature of between 150° C. and 400° C. 
     
     
         8 . A method according to  claim 1  wherein the tobacco stems are expanded such that the filling power of the stems is increased by at least 20%. 
     
     
         9 . A method according to  claim 1  wherein the cutting step comprises cutting the rolled stems to a cut width of between 0.3 to 1.3 mm. 
     
     
         10 . A method according to  claim 1  further comprising the step of applying a casing solution to the rolled, conditioned stems prior to the cutting step. 
     
     
         11 . A method according to  claim 9  comprising applying an aqueous casing solution comprising a humectant. 
     
     
         12 . A method according to  claim 1  further comprising the additional steps of:
 removing the stems from the tobacco leaf; 
 cutting the stems to an average length of between 15 mm and 80 mm; 
 conditioning the stems to increase the moisture content; and 
 rolling the stems to a thickness of between 0.1 mm and 0.5 mm, 
 
       wherein the additional steps are carried out prior to the steps of  claim 1 . 
     
     
         13 . A method according to  claim 12  wherein the conditioning of the stems increases the moisture content to 35% o.v. or less. 
     
     
         14 . A method of producing cut filler comprising expanded tobacco stems, the method comprising:
 producing expanded tobacco stems using a method according to any preceding claim; and   blending the expanded tobacco stems with at least one type of tobacco lamina, expanded tobacco or reconstituted tobacco to produce cut filler.   
     
     
         15 . A method according to  claim 2  wherein during the conditioning step the moisture content of the tobacco stems is increased to at least 12% o.v. 
     
     
         16 . A method according to  claim 15  wherein during the re-conditioning step the moisture content of the tobacco stems is increased to at least 10% o.v. 
     
     
         17 . A method according to  claim 1  wherein during the conditioning step the moisture content of the tobacco stems is increased to at least 12% o.v. and wherein during the re-conditioning step the moisture content of the tobacco stems is increased to at least 10% o.v. 
     
     
         18 . A method according to  claim 2  wherein each of the conditioning and re-conditioning steps comprises contacting the tobacco with steam, water or a mixture of steam and water. 
     
     
         19 . A method according to  claim 2  wherein the impregnation of the tobacco stems with liquid carbon dioxide is carried out under a vacuum. 
     
     
         20 . A method according to  claim 2  wherein during the heating step the tobacco stems are heated in a stream of hot gas at a temperature of between 150° C. and 400° C.