Tobacco – Tobacco treatment
Reexamination Certificate
1998-11-18
2001-10-09
Derrington, James (Department: 1731)
Tobacco
Tobacco treatment
C131S276000, C131S278000, C131S296000
Reexamination Certificate
active
06298858
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to flavor and aroma substances for tobacco materials, and to methods for manufacturing same.
BACKGROUND OF THE INVENTION
Popular smoking articles, such as cigarettes, have a substantially cylindrical rod shaped structure and include a charge of smokable material, such as shreds or strands of tobacco material (i.e., in cut filler form), surrounded by a paper wrapper, thereby forming a tobacco rod. It has become desirable to manufacture a cigarette having a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element includes cellulose acetate tow circumscribed by plug wrap, and is attached to the tobacco rod using a circumscribing tipping material. Many cigarettes include processed tobacco materials and/or tobacco extracts in order to provide certain flavorful characteristics to those cigarettes.
Flavor and aroma are important characteristics of smoking articles. To improve the flavor and aroma in smoking articles, flavorful and aromatic substances, including various natural extracts, have been included in smoking articles.
For example, U.S. Pat. No. 3,424,171 describes a process for the production of a non-tobacco smokable product having a tobacco taste. Tobacco is subjected to a moderate (i.e. below scorching) heat treatment i.e., at from about 175° to 200° C. (350° C. to 400° F.), to drive off aromatic components. These components are trapped on adsorbent charcoal, and removed from the charcoal by solvent extraction. The smokable product disclosed is vegetable matter, treated with the mixture of tobacco aromatic components and the solvent.
Similarly, U.S. Pat. No. 4,150,677 describes a process for the treatment of tobacco which comprises the steps of: (1) contacting tobacco which contains relatively high quantities of desirable flavorants with a stream of non-reactive gas, under conditions whereby the tobacco is heated in a temperature range from about 140° to 180° C.; (2) condensing the volatile constituents of the resulting gaseous stream; and (3) collecting said condensate. The condensate may be used subsequently to flavor a smoking material in order to enhance the organoleptic qualities of its smoke.
U.S. Pat. Nos. 5,038,802 to White et al. and 5,016,654 to Bernasek et al. disclose extraction processes which heat tobacco and then pass an inert atmosphere through the heating chamber to collect volatiles from the tobacco. The volatiles are then fractionated in downstream operations, which include liquid sorbents, cold temperature traps, and filters.
Flavorful and aromatic substances can also be produced from reactions of chemical materials in vitro or by adding chemicals to tobacco and reacting such added chemicals with endogenous compounds within tobacco materials.
For example, U.S. Pat. No. 3,478,015 to Onishi et al. discloses making aromatic materials by heating an amino acid and a sugar in the presence of a polyhydric alcohol. Similarly, U.S. Pat. No. 4,306,577 describes reacting reducing sugars and selected amino acids in the presence of ammonium hydroxide and optionally in the presence of an aldehyde. The flavorful materials produced can be incorporated into tobacco materials.
While these processes have produced flavor substances acceptable for use in many smoking articles, they have either been based on non-tobacco materials, or necessarily required the forming of a tobacco extract prior to the obtaining of the desired compound. Moreover, many of these processes required multiple steps of processing.
SUMMARY OF THE INVENTION
The present invention generally relates to natural tobacco flavoring substances useful in tobacco smoking products, and a method for providing flavorful and aromatic substances in tobacco materials.
The flavoring substances of this invention are prepared in situ by treatment of a tobacco blend w including a first tobacco material having a relatively high nitrogen source content and a relatively low sugar source content with a second tobacco material having a relatively low nitrogen source content and a relatively high sugar source content. The moisture content of the tobacco blend is adjusted to an amount of at least about 15% by weight, preferably at least about 20% by weight, more preferably from about 20% to about 40% by weight. The tobacco blend is then subjected to heat treatment under conditions sufficient to raise the temperature of the tobacco blend above about 250° F., preferably above about 260° F., more preferably above 270° F. As a result of this treatment, flavorful and aromatic substances are generated in the tobacco blend.
The flavorful and aromatic substances produced in the method of this invention are products of the Maillard reactions and comprise a complex mixture of volatile, semi-volatile, and non-volatile aroma/flavor components. The tobacco blend treated according to the invention and containing the flavorful and aromatic substances is typically subjected to a reordering treatment to increase its moisture content to the desired level of 10%-14% and then can be used directly in the manufacture of conventional cigarettes or other smoking articles without the need of any further flavorant additives or treatment.
In accord with the invention, the first and second tobacco materials are chosen such that the first tobacco material has a relatively high nitrogen source content and relatively low sugar source content as compared to the second tobacco material. This is achieved preferably by selection of the appropriate types of natural tobacco materials for the tobacco blend. In general, burley tobacco or another air dried tobacco which has a high nitrogen source content and a low sugar source content is used as the first tobacco material, while flue cured tobacco which has a high sugar source content and low nitrogen source content is suitable for the second tobacco material. Preferably, the tobacco materials in the blend are tobacco laminae or tobacco cut fillers, and can be used directly, after the process of this invention, in manufacturing of smoking articles such as cigarettes.
Typically, the moisture content of the tobacco blend is increased prior to heat treatment by intimately contacting the tobacco materials in the blend with water and allowing the water to be absorbed into the tobacco materials so that the resultant tobacco blend having an increased moisture content is substantially free of unabsorbed water. Optionally, flavorant additives (e.g., amino acids, amino acid analogs or amino acid sources or other nitrogen sources, and/or sugar or sugar sources) may be added, if desired, to the tobacco material prior to heat treatment. However, in preferred embodiments of the invention the tobacco blend is substantially free of exogenous, i.e., added sugar. Most preferably water which is substantially free of any additives is used to increase the moisture content of the tobacco materials in the tobacco blend, and the resultant tobacco blend which is subsequently subjected to heat treatment is substantially free of exogenous materials such as sugar or amino acids, or other chemicals.
The tobacco blend is subjected to the high temperature heat treatment for a time sufficient to alter the organoleptic characteristics (e.g., the flavor and aroma characteristics) of the blended tobacco material. Normally, the tobacco material is heated to a temperature above 250° F. preferably above 260° F. for a period of time sufficient to reduce the moisture content of the blended tobacco materials to below about 8% by weight, preferably about 6% by weight. Heating for a time period sufficient to achieve such reduction of the moisture content ensures that the tobacco blend temperature is sufficiently elevated to effect the desired increase in aroma/flavor compounds. It is preferable that the process of the invention is carried out so that the tobacco material is not exposed to such a high temperature for such a long period of time so as to provide an aroma/flavor which exhibits a burnt or tarry aroma/flavor. Accordingly, the blend is pref
Coleman, III William Monroe
Dominguez Luis Mayan
Dube Michael Francis
Parks Ronald Lewis
Perfetti Thomas Albert
Derrington James
R. J. Reynolds Tobacco Company
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