Deposition of vaporized flavorant on tobacco

Abstract

Tobacco is treated by introducing a tobacco flavorant vapor such as menthol vapor into a conduit .[.an.]. .Iadd.and .Iaddend.pneumatically conveying the vapor through the conduit. .[.The air in the conduit being maintained at a temperature of from about 75° to 150° F and above the vaporizing temperature of the flavorant..]. Tobacco is injected into the conduit at a point downstream from the vapor injection. The flavorant vapor is uniformly deposited on the tobacco as it is carried down the conduit. A predetermined level of flavorant is maintained in the conduit through which the tobacco and flavorant vapor are pneumatically conveyed. .Iadd.The air in the conduit is maintained at a temperature of from about 75° to 150° F, which temperature is sufficient to prevent condensation of the vaporized flavorant in the conduit prior to adsorption of the flavorant on the tobacco. .Iaddend.

I claim: 
     
       1. A method of treating tobacco comprising: a. introducing by vapor injection a tobacco flavorant in heated vapor form in the absence of a volatile or semi-volatile carrier fluid, into a conduit having a heated air stream maintained at a temperature within the range of from about 75° to 150° F, the temperature of said air stream being .[.above the vaporizing temperature of the flavorant.]. .Iadd.maintained at a level sufficient to prevent condensation of said vaporized flavorant in said conduit prior to adsorption of said flavorant on the tobacco.Iaddend., the vaporized flavorant being a material selected from the group consisting of menthol, anethol, benzyl.[.;.]. benzoate, cinnamaldehyde, coumarin, eugenol, heliotropin, menthone, methyl salicylate, propylene glycol, gamma-undecalactone and vanillin, a proportion of from .[.15.]. .Iadd.5 .Iaddend.to 30 milligrams per cubic foot of heated air to form a uniform concentration of said vaporized flavorant in said air stream;   b. injecting tobacco into said conduit and into said mixture of said heated air and vaporized flavorant at a point downstream from said vapor injection at the outlet side of a negative pressure producing means;   c. keeping said tobacco and vaporized flavorant in said conduit in contact for a period of time of .[.from.]. between 3 and 15 seconds to permit uniform adsorption of said flavorant whereby a flavorant level .[.of at least about 0.2 percent.]. on said tobacco is obtained; and finally separating the flavored tobacco from said conduit.   
     
     
       2. The invention in accordance with claim 1 wherein the vapor is menthol vapor and the concentration of menthol vapor in said conduit at said tobacco injection point is from .[.about 5.]. .Iadd.15 .Iaddend.to 30 milligrams per cubic foot .Iadd.of heated air and said flavorant level of menthol obtained on said tobacco is at least 0.2 percent by weight of tobacco.Iaddend.. 
     
     
       3. The invention in accordance with claim 1 including the steps of separating the .[.menthol-treated.]. .Iadd.flavorant-treated .Iaddend.tobacco from said air stream, thereafter, recycling said separated air stream to said conduit. 
     
     
       4. A method of treating tobacco comprising: a. introducing by vapor injection menthol in heated vapor form in the absence of a volatile or semi-volatile carrier fluid into a conduit having a heated air stream maintained at a temperature within the range of from .[˜]. 75° to 150° F, the temperature of said air stream being .[.above the vaporizing temperature of said menthol.]. .Iadd.maintained at a level sufficient to prevent condensation of said vaporized flavorant in said conduit prior to adsorption of said menthol on the tobacco.Iaddend., a vaporized menthol being in the proportion of from between 15 to 30 milligrams per cubic foot of heated air to form a uniform concentration of said menthol in said air stream;   b. injecting tobacco into said conduit and into said mixture of said heated air and vaporized menthol at a point downstream from said vapor injection at the outlet side of a negative pressure producing means;   c. keeping said tobacco and vaporized menthol in said conduit in contact for a period of time of .[.from.]. between 3 and 15 seconds to permit uniform adsorption of said menthol at a menthol level of at least .[˜]. 0.2 percent on said tobacco; and finally separating the flavored tobacco from said conduit.   
     
     
       5. The invention in accordance with claim 4 including the steps of separating the menthol-treated tobacco from said air stream and thereafter recycling said air stream to said conduit. 
     
     
       6. The method in accordance with claim 4 in which the temperature of .[.the pneumatic.]. .Iadd.said heated air .Iaddend.stream is between 100° and 115° F.