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US 7,404,406 B2Granted
Tobacco processing
AssigneeR. J. Reynolds Tobacco Company
InventorDavid McCray Peele
Life of this patent
Estimating the term…
Abstract
Tobaccos are cured in a manner so as to provide tobaccos having extremely low tobacco specific nitrosamine (TSNA) contents. Harvested Virginia tobacco is subjected to flue-curing so as to provide flue-cured tobacco. During the curing processing steps, contact of the tobacco with nitric oxide gases, such as those produced as combustion products of propane burning heating units, is avoided. Tobacco in curing barns is not subjected to direct-fire curing techniques, but rather, heat for tobacco curing can be provided by heat exchange or electrical heating methods.
Claims44
A method for preparing cured Virginia tobacco having a TSNA content below 2 ppm, based on the dry weight of the cured tobacco, comprising the steps of:
- providing a barn having an air circulation device and a heat exchange unit;
- putting harvested green Virginia tobacco in the barn;
- producing heated air and exhaust gases through the act of burning a propane or diesel fuel in the heat exchange unit;
- preventing substantially all of the exhaust gases, produced through the act of burning a propane or diesel fuel in the heat exchange unit, from contacting the harvested tobacco and from causing a chemical reaction therewith;
- circulating the heated air with the aid of the air circulation device, produced through the act of burning a propane or diesel fuel in the heat exchange unit, through the barn for at least about 120 hours in the absence of substantially all of the exhaust gases to produce cured tobacco while substantially preventing formation of TSNA in the cured tobacco that would otherwise be formed as a result of the chemical reaction;
- making a determination that the TSNA content of the cured tobacco is below 2 ppm;
- and
- correlating the determination of the TSNA content of the cured tobacco being below 2 ppm with the preparation of the cured tobacco in a barn having a heat exchange unit wherein the heat exchange unit suppresses the exposure of the tobacco to nitric oxide gases.
5 more elements
A method for preparing cured Virginia tobacco having a TSNA content below 2 ppm, based on the dry weight of the cured tobacco, comprising the steps of:
- providing a barn having an air circulation device and a heat exchange unit;
- putting harvested green Virginia tobacco in the barn;
- producing heated air and exhaust gases through the act of burning a propane or diesel fuel in the heat exchange unit wherein the exhaust gases comprise nitric oxide gases;
- preventing substantially all of the exhaust gases, produced through the act of burning a propane or diesel fuel in the heat exchange unit, from contacting the harvested tobacco and from causing a chemical reaction therewith;
- circulating the heated air with the aid of the air circulation device, produced through the act of burning a propane or diesel fuel, in the heat exchange unit, through the barn for at least about 120 hours in the absence of substantially all of the exhaust gases to produce cured tobacco while substantially preventing formation of TSNA in the cured tobacco that would otherwise be formed as a result of the chemical reaction;
- making a determination that the TSNA content of the cured tobacco is below 2 ppm;
- and
- correlating the determination of the TSNA content of the cured tobacco being below 2 ppm with the preparation of cured tobacco that is not contacted by the nitric oxide gases produced during curing.
5 more elements
A method for preparing cured Virginia tobacco having a TSNA content below 2 ppm, based on the dry weight of the cured tobacco, comprising the steps of:
- providing a barn having an air circulation device and a heat exchange unit;
- putting harvested green Virginia tobacco in the barn;
- producing heated air and exhaust gases through the act of burning a propane or diesel fuel in the heat exchange unit wherein the exhaust gases comprise nitric oxide gases;
- preventing substantially all of the exhaust gases, produced through the act of burning a propane or diesel fuel in the heat exchange unit, from contacting the harvested tobacco and from causing a chemical reaction therewith;
- circulating the heated air with the aid of the air circulation device, produced through the act of burning a propane or diesel fuel, in the heat exchange unit, through the barn for at least about 120 hours in the absence of substantially all of the exhaust gases to produce cured tobacco while substantially preventing formation of TSNA in the cured tobacco that would otherwise be formed as a result of the chemical reaction;
- making a determination that the TSNA content of the cured tobacco is below 2 ppm;
- and
- correlating the determination of the TSNA content of the cured tobacco being below 2 ppm with the preparation of cured tobacco that does not react with the nitric oxide gases during curing.
5 more elements
A method for preparing a tobacco product from cured Virginia tobacco having a TSNA content below 2 ppm, based on the dry weight of the cured tobacco, comprising the steps of:
- providing a barn having an air circulation device and a heat exchange unit;
- putting harvested green Virginia tobacco in the barn;
- producing heated air and exhaust gases through the act of burning a propane or diesel fuel in the heat exchange unit wherein the exhaust gases comprise nitric oxide gases;
- preventing substantially all of the exhaust gases, produced through the act of burning a propane or diesel fuel in the heat exchange unit, from contacting the harvested tobacco and from causing a chemical reaction therewith;
- circulating the heated air with the aid of the air circulation device, produced through the act of burning a propane or diesel fuel, in the heat exchange unit, through the barn for at least about 120 hours in the absence of substantially all of the exhaust gases to produce cured tobacco while substantially preventing formation of TSNA in the cured tobacco that would otherwise be formed as a result of the chemical reaction;
- determining that the TSNA content of the cured tobacco is below 2 ppm;
- correlating the determination of the TSNA content of the cured tobacco being below 2 ppm with the preparation of cured tobacco that is not contacted by the nitric oxide gases produced during curing;
- and
- incorporating the cured tobacco into a tobacco product;
- wherein the TSNA content of the tobacco in the tobacco product is below 2 ppm.
7 more elements
A method for preparing cured Virginia tobacco comprising the steps of:
- (a) placing harvested green Virginia tobacco in a barn;
- (b) circulating heated air through the tobacco in the barn for at least about 120 hours to produce cured tobacco;
- wherein the air is heated by burning a propane or diesel fuel in a heat exchanger and circulating the air through the heat exchanger and the barn with a fan, such that the tobacco is not exposed to the nitric oxide gases produced by burning a propane or diesel fuel;
- and wherein the step of circulating heated air comprises:
- yellowing the tobacco for about 48 total hours at about 35° C.,
- increasing the temperature about 1° C. per hour to about 49° C.,
- drying the tobacco for an additional about 10 hours at about 49° C.,
- increasing the temperature about 1° C. per hour to about 57° C.,
- drying the tobacco for an additional about 14 hours at about 57° C.,
- increasing the temperature about 1° C. per hour to about 74° C., and
- drying the tobacco until the midribs are dry;
- (c) turning the heat off;
- (d) opening the doors of the barn;
- (e) reordering the cured tobacco by contacting it with ambient air;
- (f) making a determination that the TSNA content of the cured tobacco is significantly reduced compared to tobacco cured with heated air containing nitric oxide gases produced from the burning of a propane or diesel fuel;
- and
- (g) correlating the determination that the significantly reduced TSNA content of the cured tobacco with the preparation of cured tobacco that is not contacted by the nitric oxide gases produced during curing.
14 more elements
In a method for preparing a tobacco product from cured Virginia tobacco comprising the steps of placing harvested green Virginia tobacco in a barn and circulating heated air through the tobacco in the barn for at least about 120 hours to produce cured tobacco;
- wherein the air is heated by burning a propane or diesel fuel in a heat exchanger and circulating the air through the heat exchanger and the barn with a fan, such that the tobacco is not exposed to the nitric oxide gases produced by burning the a propane or diesel fuel;
- wherein the improvement comprises the steps of:
- making a determination that the TSNA content of the cured tobacco is significantly reduced compared to tobacco cured with heated air containing nitric oxide gases from the burning of a propane or diesel fuel;
- correlating the determination that the significantly reduced TSNA content of the cured tobacco with the preparation of cured tobacco that is not contacted by the nitric oxide gases produced during curing;
- and
- incorporating the cured tobacco into a tobacco product;
- wherein the TSNA content of the tobacco in the tobacco product is significantly reduced compared to tobacco cured with heated air containing nitric oxide gases from the burning of a propane or diesel fuel.
4 more elements
In a method for preparing cured Virginia tobacco comprising the steps of:
- providing a barn having an air circulation device and a heat exchange unit;
- putting harvested green Virginia tobacco in the barn;
- producing heated air and exhaust gases through the act of burning a propane or diesel fuel in the heat exchange unit;
- preventing substantially all of the exhaust gases, produced through the act of burning a propane or diesel fuel in the heat exchange unit, from contacting the harvested tobacco and from causing a chemical reaction therewith;
- and
- circulating the heated air with the aid of the air circulation device, produced through the act of burning a propane or diesel fuel, in the heat exchange unit, through the barn for at least about 120 hours in the absence of substantially all of the exhaust gases to produce cured tobacco while substantially preventing formation of TSNA in the cured tobacco that would otherwise be formed as a result of the chemical reaction;
- wherein the improvement comprises:
- making a determination that the TSNA content of the cured tobacco is significantly reduced compared to tobacco cured with heated air containing nitric oxide gases from the burning of a propane or diesel fuel;
- and
- correlating the determination that the significantly reduced TSNA content of the cured tobacco with the preparation of cured tobacco that is not contacted by the nitric oxide gases produced during curing.
7 more elements
Dependencies are inferred from the claim text.