Thermal treatment process for tobacco materials

Abstract

A method of preparing a tobacco material for use in a smoking article is provided, including (i) mixing a tobacco material, water, and an additive selected from the group consisting of lysine, glycine, histidine, alanine, methionine, glutamic acid, aspartic acid, proline, phenylalanine, valine, arginine, di- and trivalent cations, asparaginase, saccharides, phenolic compounds, reducing agents, compounds having a free thiol group, oxidizing agents, oxidation catalysts, plant extracts, and combinations thereof; (ii) heating the mixture; and (iii) incorporating the heat-treated mixture into a smoking article as a smokable material. A smoking article in the form of a cigarette is also provided that includes a tobacco material pre-treated to inhibit reaction of asparagine to form acrylamide in mainstream smoke. Upon smoking, the smoking article is characterized by an acrylamide content of mainstream smoke that is reduced relative to an untreated control smoking article.

1 - 26 . (canceled) 
     
     
         27 . A method of preparing a tobacco product with reduced acrylamide content, comprising:
 (i) mixing a tobacco material, water, and asparaginase to form a moist tobacco mixture;   (ii) heating the moist tobacco mixture to form a heat-treated tobacco mixture, wherein the pH of the moist tobacco mixture during the heating step is less than about 10; and   (iii) incorporating the heat-treated tobacco mixture into a smoking article or into a smokeless tobacco product.   
     
     
         28 . The method of  claim 27 , wherein the asparaginase is present in an amount of between about 100 ppm to about 10 weight percent, based on the dry weight of the tobacco mixture. 
     
     
         29 . The method of  claim 27 , wherein the asparaginase is present in an amount of between about 100 ppm to about 1,000 ppm, based on the dry weight of the tobacco mixture. 
     
     
         30 . The method of  claim 27 , wherein the asparaginase is in the form of an aqueous dispersion containing less than 10 weight percent total organic solids. 
     
     
         31 . The method of  claim 27 , wherein the number of asparaginase units (ASNU) per gram of asparaginase composition is in the range of 3000 to 4000. 
     
     
         32 . The method of  claim 27 , wherein the heat-treated tobacco mixture comprises less than about 2000 ppb of acrylamide. 
     
     
         33 . The method of  claim 32 , wherein the heat-treated tobacco mixture comprises less than about 1500 ppb of acrylamide. 
     
     
         34 . The method of  claim 33 , wherein the heat-treated tobacco mixture comprises less than about 1000 ppb of acrylamide. 
     
     
         35 . The method of  claim 27 , wherein the temperature of the heating step is greater than about 60° C. 
     
     
         36 . The method of  claim 35 , wherein the temperature of the heating step is greater than about 100° C. 
     
     
         37 . The method of  claim 27 , wherein the heat-treated tobacco mixture has a moisture content of no more than about 10 weight percent. 
     
     
         38 . The method of  claim 27 , wherein the heat-treated tobacco mixture includes one or more further components selected from flavorants, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants, and preservatives. 
     
     
         39 . The method of  claim 27 , wherein the tobacco material is in a shredded or particulate form or in the form of an extract. 
     
     
         40 . The method of  claim 27 , wherein the heat-treated tobacco mixture is incorporated into a cigarette. 
     
     
         41 . The method of  claim 40 , wherein the cigarette comprises a rod of smokable material circumscribed by a wrapping material and a filter attached to the rod at one end thereof, wherein the smokable material comprises the heat-treated tobacco mixture. 
     
     
         42 . The method of  claim 41 , wherein the cigarette, upon smoking, is characterized by an acrylamide content of mainstream smoke that is reduced relative to an untreated control smoking article. 
     
     
         43 . The method of  claim 42 , wherein the amount of acrylamide reduction by weight in mainstream smoke is at least about 10 percent as compared to an untreated control smoking article. 
     
     
         44 . The method of  claim 43 , wherein the amount of acrylamide reduction in mainstream smoke is at least about 30 percent as compared to an untreated control smoking article. 
     
     
         45 . The method of  claim 44 , wherein the amount of acrylamide reduction in mainstream smoke is at least about 50 percent as compared to an untreated control smoking article. 
     
     
         46 . The method of  claim 45 , wherein the amount of acrylamide reduction in mainstream smoke is at least about 60 percent as compared to an untreated control smoking article. 
     
     
         47 . A smoking article in the form of a cigarette prepared according to the method of  claim 27 . 
     
     
         48 . A smokeless tobacco product prepared according to the method of  claim 27 . 
     
     
         49 . A tobacco product comprising a tobacco material pre-treated to inhibit reaction of asparagine to form acrylamide, wherein the pre-treatment comprises heating the tobacco material at a pH of less than about 10 in the presence of water and asparaginase. 
     
     
         50 . The tobacco product of  claim 49 , wherein the tobacco product is in the form of a cigarette comprising a rod of smokable material circumscribed by a wrapping material and a filter attached to the rod at one end thereof, wherein the smokable material comprises the pre-treated tobacco material. 
     
     
         51 . The tobacco product of  claim 50 , wherein the cigarette, upon smoking, is characterized by an acrylamide content of mainstream smoke that is reduced relative to an untreated control smoking article. 
     
     
         52 . The tobacco product of  claim 51 , wherein the amount of acrylamide reduction by weight in mainstream smoke is at least about 10 percent as compared to an untreated control smoking article. 
     
     
         53 . The tobacco product of  claim 52 , wherein the amount of acrylamide reduction in mainstream smoke is at least about 30 percent as compared to an untreated control smoking article. 
     
     
         54 . The tobacco product of  claim 53 , wherein the amount of acrylamide reduction in mainstream smoke is at least about 50 percent as compared to an untreated control smoking article. 
     
     
         55 . The tobacco product of  claim 54 , wherein the amount of acrylamide reduction in mainstream smoke is at least about 60 percent as compared to an untreated control smoking article. 
     
     
         56 . The tobacco product of  claim 49 , wherein the tobacco product is in the form of a smokeless tobacco product. 
     
     
         57 . The method of  claim 49 , wherein the pre-treated tobacco material comprises less than about 2000 ppb of acrylamide. 
     
     
         58 . The method of  claim 57 , wherein the pre-treated tobacco material comprises less than about 1500 ppb of acrylamide. 
     
     
         59 . The method of  claim 58 , wherein the pre-treated tobacco material comprises less than about 1000 ppb of acrylamide.