Tobacco treatment process

A process is provided for treating tobacco material for use in a smoking article comprising the step of applying a flavorful and aromatic casing and top dressing composition comprising a weak ammonium salt and a sugar or sugar derivative to a tobacco material. The present also provides a smoking article including tobacco material wherein the tobacco material is in intimate contact with a casing and top casing composition comprising a weak ammonium salt and a sugar or sugar derivative.

BACKGROUND OF THE INVENTION 
The present invention relates to providing a flavorful and aromatic 
additive. Such additive is applied as a casing or top coating to a tobacco 
material. 
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. 
Cigarettes are employed by the smoker by burning one end thereof. The 
smoker then receives mainstream smoke into his/her mouth by drawing on the 
opposite end (e.g., filter end) of the cigarette. Typically, a person 
using a cigarette draws on or puffs the article about 5 to about 10 times, 
and each puff lasts about 0.5 second to about 2 seconds. Typically, a 
burning cigarette has a useful lifetime of about 1 minute to about 10 
minutes. Various types of tobaccos and other materials can be blended to 
form the cut filler of a cigarette. Generally, various amounts of 
flue-cured, Burley, Maryland and Oriental tobaccos are blended together 
and ultimately form cut filler. A typical blend also can include 
reconstituted tobacco material, volume expanded processed tobacco, cut 
rolled stems, tobacco substitutes, and other such materials. The cut 
filler frequently is treated with volatile additives such as top dressing 
or flavors in the form of an alcoholic solution. See, for example, British 
Pat. No. 910,451 to Davis and U.S. Pat. No. 4,819,668 to Shelar et al. 
In addition to the volatile "top flavor" additives, another category of 
additives having a relatively low degree of volatility is also customarily 
applied to tobacco. This category includes materials such as sugars, 
licorice, cocoa, essential oils, fruit extracts and humectant. These 
materials are known in the art as "casing" materials and they are applied 
to the tobacco by dipping or spraying prior to the cutting or shredding 
operation. 
There has been interest in other additives based on amino acids or sugars. 
For example, U.S. Pat. No. Re. 32,095 to Wu et al. proposes reacting 
sugars with ammonium hydroxide in the presence of a trace amount of an 
amino acid to provide flavorants suitable for use in smoking articles. 
It would be highly desirable to provide flavorful and aromatic casing and 
top dressing compound which compliment the flavor and aroma 
characteristics of smokable materials. 
SUMMARY OF THE INVENTION 
A process for treating tobacco material for use in a smoking article 
comprising the step of applying a flavorful and aromatic casing and top 
dressing composition comprising a weak ammonium salt and a sugar or sugar 
derivative to a tobacco material is provided. The present invention also 
provides a smoking article including tobacco material wherein the tobacco 
material is in intimate contact with a casing and top casing composition 
comprising a weak ammonium salt and a sugar or sugar derivative. Exemplary 
sugars include fructose, glucose, galactose, sucrose, rhamnose, maltose, 
xylose, and mannose. As used herein, the term "weak ammonium salt" relates 
to ammonium salts formed from acids having a low ionization constant and a 
small disassociation constant. The weak acids readily release ammonia 
during heating as compared to strong acids. Suitable weak ammonium salts 
include ammonium phosphate, diammonium phosphate, ammonium bicarbonate, 
ammonium carbonate, ammonium citrate, diammonium citrate, ammonium 
levulinate, ammonium alginate, ammonium monocarboxylic acids and ammonium 
dicarboxylic acids. 
The aromatic and flavorful casing and top dressing composition is applied 
so as to be in intimate contact with the smoking material (e.g., the cut 
filler). The aromatic and flavorful casing and top dressing composition is 
used in an amount sufficient to provide an alteration in flavor and aroma 
of the smoking material of the cigarette upon burning during use. 
The present invention allows the smoker to enjoy good tobacco taste upon 
smoking the smoking article (e.g., a cigarette). In particular, the aroma 
provided by the chemical rearrangement of the flavorful and aromatic 
casing and top dressing composition during the use of the smoking article 
can be such so as to override the odor of the ensuing sidestream smoke, 
and thereby suppress the odor thereof. In particular, the taste of the 
mainstream smoke is complemented or not adversely affected by the 
compounds provided by the rearrangement of the aromatic and flavorful 
precursor. For example, the flavor characteristics provided to the 
mainstream smoke by the aromatic and flavorful compounds are not so 
overpowering so as to deleteriously affect or otherwise provide 
undesirable off-tastes to the mainstream smoke. 
DETAILED DESCRIPTION OF THE INVENTION 
As summarized above, the process of the present invention includes applying 
a flavorful and aromatic casing and top dressing composition comprising a 
weak ammonium salt and a sugar to a smokable material. The weak ammonium 
salts typically have a low ionization constant and a small disassociation 
constant. 
Examples of suitable sugars are fructose, glucose, galactose, sucrose, 
rhamnose, maltose, xylose, and mannose, and other monosaccharides and 
disaccharides, or the sugar derivatives such as .alpha.-dicarbonyl 
compounds and .alpha.-hydroxy carbonyl compounds. As used herein, the term 
"sugar derivative" relates to the fact that sugars undergo degradation via 
a rearrangement mechanism to form .alpha.-dicarbonyl compounds such as 
2,3-pentanedione, 2,3-butanedione, 3,4-hexanedione, 2,3-hexanedione, etc. 
or to form .alpha.-hydroxy carbonyl compounds such as acetol, acetoin, 
2-hydroxy-3-pentanone, 4-hydroxy-3-hexanone, etc. Thus, a sugar derivative 
can be the resulting .alpha.-dicarbonyl compound or .alpha.-hydroxy 
carbonyl compound or can be a compound that forms an .alpha.-dicarbonyl or 
.alpha.-hydroxy carbonyl after degradation. 
The amount of the aromatic and flavorful casing and top coating composition 
employed can vary. The amount in intimate contact with the tobacco 
material (e.g., cut filler) ranges from 0.1 mg to about 25 mg per 
cigarette, and frequently about 0.15 to about 5 mg cigarette. 
The smokable material employed in the manufacture of the smokable rod can 
vary, the most preferably has the form of cut filler. As used herein, the 
term "cut filler" in referring to smokable materials is meant to include 
smokable materials which have a form suitable for use in the manufacture 
of smokable rods for smoking articles such as cigarettes. As such, cut 
filler can include smokable materials which are blended and are in a form 
ready for cigarette manufacture. Smokable materials normally are employed 
in the form of strands or shreds as in common in cigarette manufacture. 
For example, cut filler can be employed in the form of strands or shreds 
cut from sheet-like or "strip" materials. Such strip materials are cut 
into widths ranging from about 1/5 inch to about 1/60 inch, preferably 
from about 1/25 inch to about 1/35 inch. Generally, the resulting strands 
or shreds have lengths which range from about 0.25 inch to about 3 inches. 
Cut filler also can have an extruded form (e.g., extruded strands), or 
other physically processed form. 
The coated tobacco cut filler having the casing and top dressing 
composition in contact therewith may be combined with aerosol forming 
materials, and employed in the manufacture of those smoking articles 
described in U.S. Pat. Nos. 4,708,151 to Shelar; 4,771,795 to White et 
al.; 4,714,082 to Banerjee et al.; 4,756,318 to Clearman et al.; and 
4,793,365 to Sensabaugh et al., the disclosures of which are incorporated 
herein by reference, as well as European Patent Publication Nos. 212,234 
and 277,519. In addition, the coated tobacco cut filler can be 
incorporated into those smoking articles described in commonly assigned 
U.S. Pat. application Ser. No. 07/414,833 filed Sep. 29, 1989 and European 
Patent Publication No. 280,990. 
Upon experiencing the temperatures of a burning smoking article, the 
flavorful and aromatic casing and top casing composition undergoes a 
change in the chemical nature to form a plurality of compounds that as a 
whole provide a characteristic flavor and aroma. Conditions provided 
during the burning of a smoking article most desirably are such that the 
ammonium salt and sugars undergo Maillard reactions or "browning 
reactions". See Maillard, Ana. Chim., Vol. 9, pp. 5 and 258 (1916); Hodge, 
J. Agric Food Chem., Vol. 1, p. 928 (1953); Nursten, Food Chem., Vol. 6, 
p. 263 (1981) and Waller et al., ACS Symp. Ser. (1983). Such reactions 
result in a significant darkening of the mixture. Additionally, flavoring 
agents (e.g., cocoa, licorice, St. John's bread, spices, herbs, and the 
like) can be added to the mixture to further enhance the flavor and 
aromatic characteristics of the resulting composition.

The following examples are provided in order to further illustrate 
preferred aspects of the invention but should not be construed as limiting 
the scope thereof. Unless otherwise noted, all parts and percentages are 
by weight. 
EXAMPLE 1 
Five pounds of Burley tobacco are charged into a tumbling drum, and are 
sprayed with a solution of diammonium phosphate (81 grams), glucose (220 
grams) and water (750 ml). The tobacco is placed into an oven (Sargeant 
Dryer), and heated between 310.degree. to 320.degree. F. for 2.5 min and 2 
min of updraft and downdraft respectively. The moisture of the tobacco is 
adjusted to 12.1 percent with water prior to cigarette making. 
Another five pounds of Burley tobacco is also treated under the same 
conditions as the control sample except that no diammonium phosphate and 
glucose were added. A comparison between the aroma of the test tobacco and 
the control tobacco revealed that the test tobacco possessed strong 
pleasant notes including sweet, roasted, chocolate-like, fruity notes with 
a rounded tobacco aroma. 
Both the control cigarettes and the test cigarettes were smoked by an 
expert panel and the panel agreed that the test cigarettes were preferred, 
the test cigarettes were described as possessing a well rounded, smooth, 
sweet, toasted, cocoa/chocolate-like character. 
EXAMPLE 2 
The procedure of Example 1 is repeated except that 137 grams of diammonium 
citrate is used. The test tobacco also showed aroma characteristics 
superior to the control tobacco. 
EXAMPLE 3 
The procedure of Example 1 is repeated except that 96 grams of ammonium 
bicarbonate is used. The test tobacco also showed aroma characteristics 
superior to the control tobacco.