U.S. patent application number 10/527286 was filed with the patent office on 2006-06-22 for process for reducing nitrogen containing compounds and lignin in tobacco.
Invention is credited to Kenneth J. JR. Bradley, Brad L. Hayes, John-Paul Mua.
Application Number | 20060130859 10/527286 |
Document ID | / |
Family ID | 31977729 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060130859 |
Kind Code |
A1 |
Mua; John-Paul ; et
al. |
June 22, 2006 |
Process for reducing nitrogen containing compounds and lignin in
tobacco
Abstract
A process for reducing lignin and nitrogenous content in tobacco
lamina and tobacco fiber material, including whole leaf, stems,
scraps, fines and lamina, as well as burley leaf and stem, in an
extraction with a solution containing hydrogen peroxide and an
alkali metal hydroxide. The treated tobacco may then be further
processed for use in cigarettes and other smoking articles.
Inventors: |
Mua; John-Paul;
(Winston-Salem, NC) ; Hayes; Brad L.; (Dublin,
GA) ; Bradley; Kenneth J. JR.; (Macon, GA) |
Correspondence
Address: |
MIDDLETON & REUTLINGER
2500 BROWN & WILLIAMSON TOWER
LOUISVILLE
KY
40202
US
|
Family ID: |
31977729 |
Appl. No.: |
10/527286 |
Filed: |
August 28, 2003 |
PCT Filed: |
August 28, 2003 |
PCT NO: |
PCT/US03/27087 |
371 Date: |
September 9, 2005 |
Current U.S.
Class: |
131/297 ;
131/299; 131/300 |
Current CPC
Class: |
A24B 15/24 20130101;
A24B 15/243 20130101; A24B 15/245 20130101 |
Class at
Publication: |
131/297 ;
131/300; 131/299 |
International
Class: |
A24B 15/24 20060101
A24B015/24 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2002 |
US |
10237837 |
Claims
1. A method of making a tobacco material with reduced levels of
lignin and nitrogenous compounds comprising: (a) contacting a
tobacco material with a first aqueous solvent at a temperature of
about 25.degree. C. to 80.degree. C. for about 0.5 to 2 hours to
provide an aqueous tobacco extract and a tobacco fiber portion; (b)
separating said aqueous tobacco extract from said tobacco fiber
portion; (c) contacting at a temperature from about 25.degree. C.
to 120.degree. C. said tobacco fiber portion with a solution
containing hydrogen peroxide and an alkali metal hydroxide wherein
said solution contains said hydrogen peroxide in a concentration of
from 2.5% to 12.0% (w/w) and said alkali metal hydroxide is from
about 1% to 5% (w/w); and, (d) separating said solution from said
tobacco fiber portion.
2. The method of claim 1, further comprising: (e) contacting said
tobacco fiber portion with a second aqueous solvent.
3. The method of claim 1, wherein said tobacco material is
lamina.
5. The method of claim 1, wherein said alkali metal hydroxide is
sodium hydroxide.
6. The method of claim 5, wherein said sodium hydroxide is from
about 4% to 8 (w/w).
7. The method of claim 5, wherein said alkali metal hydroxide is
potassium hydroxide.
8. The method of claim 7, wherein said potassium hydroxide is from
about 4% to 8% (w/w).
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to tobacco and tobacco
smoking materials and methods of making same. More particularly,
the present invention relates to the materials and methods that
provide tobacco materials with reduced lignin and nitrogenous
content.
[0002] Tobacco material contains various nitrogenous compounds that
can adversely affect its smoke quality. Among these nitrogenous
compounds are proteins, amino acids and certain alkaloids, such as
nicotine, nornicotine, anabasine and anatabine. The smoke quality
of tobacco is adversely affected particularly by heterocyclic and
aromatic amines, and tobacco specific nitrosamines (TSNA), as well
as other compounds formed by pyrolysis or transfer of these
nitrogenous compounds. Tobacco processing sometimes includes steps
in which the nitrogen content of the tobacco is reduced so as to
improve the smokability of the tobacco. However, nitrogenous
compounds are difficult to extract from cured tobacco lamina, stem,
and fiber cell walls.
[0003] Many of the current processes used to reduce nitrogen
content in tobacco material employ enzymatic compounds and
microbial agents to break down the proteins and other
nitrogen-containing compounds within the tobacco. However,
disadvantages arise from the use of such enzymatic compounds and
agents. In particular, enzymes are expensive, pH sensitive and
degrade proteins into amino acids which tend to remain with the
tobacco material. It is also thought that enzymatic compounds leave
residues on tobacco material after processing. Furthermore,
microbial agents used in treating tobacco tend to cause unwanted
reactions that generate undesirable by-products. Moreover, in many
of these tobacco treatments, the tobacco disintegrates or easily
breaks into small pieces.
[0004] Therefore, there is a need to provide a process by which the
nitrogen content of tobacco material may be reduced without leaving
residues or undesirable by-products and the break-down of tobacco
solid materials is reduced.
SUMMARY OF THE INVENTION
[0005] The present invention relates to a method for providing a
tobacco material having a reduced lignin and nitrogenous content.
The tobacco material in the form of flue cured and burley whole
leaf lamina as well as stems, fines, or scraps is contacted with an
aqueous solvent. The resulting liquid extract is separated from a
tobacco fiber portion. The tobacco fiber portion is then contacted
with a solution containing an alkali metal hydroxide, such as
sodium hydroxide and/or potassium hydroxide, and hydrogen peroxide.
This solution is also separated from the tobacco fiber portion. The
tobacco fiber portion may then be washed, refined and further
processed for use in smoking articles, such as cigarettes. The
reduction of lignin and nitrogenous compounds in the tobacco
material provides for improved smokability and a reduction in
nitrogen containing pyrolitic products emitted from smoking
articles which contain the tobacco material.
[0006] It is an object of the present invention to provide a
tobacco product with reduced levels of lignin and nitrogenous
compounds.
[0007] It is another object of the present invention to provide a
method of making a tobacco product with reduced levels of lignin
and nitrogenous compounds.
[0008] It is a further object of the present invention to provide a
method of treating tobacco which minimizes the break-up of tobacco
solid materials.
[0009] More particularly, the present invention is directed to a
method for reducing the lignin and nitrogenous content of tobacco
material, including cured tobacco whole leaf, fines, scraps, stems,
and lamina, as well as burley leaf and stem, comprising the steps
of: contacting tobacco material with a first aqueous solvent, such
as water, at a temperature of about 60.degree. C. to 80.degree. C.
for about 0.5 to 1 hour; separating an aqueous tobacco extract from
a tobacco fiber portion; contacting this washed tobacco fiber
portion with a solution containing from 1% to 5% (weight/weight)
alkali metal hydroxide and from 2.5% to 12% (weight/weight)
hydrogen peroxide at a temperature of about 25.degree. C. to
120.degree. C. for about 0.5 to 4 hours and, separating the
resulting solution from the tobacco fiber portion. The resulting
tobacco product is then dried and used in the manufacture of
cigarette articles. Alternatively, the extract, or a portion
thereof, may be added back to the tobacco product before
drying.
[0010] A better understanding of the present invention will be
realized from the hereafter processes and the Examples following
such description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic of the process steps representative of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] In a preferred method of carrying out the lignin and
nitrogen reduction process of the present invention, tobacco
materials (10) in the form of flue cured and burley stems, scraps,
fines, and/or lamina are contacted with a first aqueous solvent
(12), such as water, at a temperature of about 60.degree. C. to
80.degree. C. for about 0.5 to 1 hour. The contacting of the
tobacco with the water (12) may be conducted in a tank or similar
mixing vessel in which the water and tobacco are heated and
agitated. The resulting aqueous tobacco extract, containing flavor
compounds, is separated from the tobacco fiber portion, preferably
by centrifugation (14). The tobacco/water slurry may be pumped into
a centrifuge from the mixing vessel and centrifugally separated
therein. Once removed from the tobacco fiber or lamina portion, the
aqueous tobacco extract (15) may be reserved for reapplication to
the fiber with or without separate processing. In one embodiment,
the aqueous tobacco extract (15) may be contacted with a solid
phase adsorbent (17), such as Bentonite or a cationic resin, in a
vessel and then separated therefrom by centrifugation (19), or a
similar separation process well known in the art. In another
embodiment, the aqueous tobacco extract (15) may be pumped or
passed through specialty filters, membranes, or column packed
adsorbent/absorbent materials to remove soluble nitrogenous
components, such as nitrates, proteins and nitrosamines (TSBAs),
and polyphenolic compounds, and the like. The nitrogen-reduced
aqueous tobacco extract containing flavor compounds may then be
concentrated (23) by vacuum evaporation, and added back to a
reconstituted tobacco paper (31).
[0013] The lignin and nitrogen content of the tobacco fiber or
lamina portion (16) separated from the aqueous tobacco extract (15)
may be reduced by contacting the tobacco fiber or lamina portion
(16) with a co-solvent solution containing an alkali metal
hydroxide, such as sodium hydroxide and/or potassium hydroxide, and
hydrogen peroxide (18). The tobacco fiber or lamina portion (16)
may be loaded into a tank or similar mixing vessel. In one
embodiment, a co-solvent containing from about 1.0% to 5.0%
(weight/weight) sodium hydroxide and 2.5% to 12.0% hydrogen
peroxide (weight/weight) of tobacco fiber, preferably from 4.0% to
8.0% hydrogen peroxide, is charged to the vessel and contacted with
the washed tobacco fiber portion at a temperature of about
25.degree. C. to 80.degree. C. for 0.5 to 2.0 hours for lamina and
from a temperature of about 70.degree. C. to 120.degree. C. for
about 0.5 to 4.0 hours for tobacco fiber. Afterward, the solution
may be separated from the tobacco fiber or lamina portion by any
means well known in the art (24), such as, for example, by pumping
the slurry to a centrifuge wherein the fiber is centrifugally
separated from the solution. The tobacco fiber or lamina portion
may then be washed with a second aqueous solvent, such as water, as
noted by numeral (26), and further refined (28). The tobacco fiber
or lamina portion may then be processed into sheets (30), to which
may be added the lignin-nitrogen reduced aqueous tobacco extract
(31). When sheets or lamina from the aforementioned process are
compared to only washed sheets or lamina, there is a 35-90%
reduction in Kjeldahl nitrogen and a 23-45% reduction in
lignin.
[0014] Additionally, potassium hydroxide (KOH) may be included in
the solution with which the tobacco fiber portion is contacted. The
tobacco fiber or lamina portion may be contacted with a solution
containing potassium hydroxide and hydrogen peroxide. The solutions
set forth may contain about the same amount of potassium hydroxide
as sodium hydroxide.
[0015] In particular, tobacco sheets and lamina formed from tobacco
material treated with alkali metal hydroxide and hydrogen peroxide
is stronger than tobacco fibers and lamina processed by
conventional methods. Also, this tobacco product exhibits a texture
and a density that are similar to that exhibited by flue cured
tobacco leaf. This tobacco product, when cut, will not crumble as
easily as similar tobacco products formed by conventional methods.
Therefore, less tobacco is wasted in the process of making smoking
articles such as cigarettes. Thus, tobacco treated by the above
described process provides advantages in the cigarette making
process over conventionally treated tobacco.
EXAMPLES
[0016] For a better understanding of the present invention, the
following Examples are incorporated herein to illustrate the
present invention with no intention of being unduly limited
thereby.
Control 1 and Example 1A, 1B
[0017] A 2.8 kg mixture of tobacco materials, including flue-cured
and burley tobacco scraps, stems, laminae and fines having a
nitrogen content of 2.09% was extracted with water at 70.degree. C.
for 30 minutes to 120 minutes as known in the art. Following
centrifugation, the liquid extract was further treated with
adsorbent (e.g. diatomaceous clay, activated charcoal, clyodextrin,
or combinations thereof or absorbent (cellulose acetate) to remove
nitrogenous compounds, and then concentrated by vacuum evaporation.
The resultant washed fiber was further extracted to remove lignin
and nitrogenous compounds, as mentioned below. From the washed
fibers, 350 g portions were then loaded into vessel containing
2.8-4.2 L of an alkaline-peroxide solution, comprising 2.5% (w/w)
sodium hydroxide and 7.5% (w/w) hydrogen peroxide. The
alkaline-peroxide solution containing the tobacco material was then
heated to 70.degree. C. and held for 0.5-1 h while being agitated.
After each period of heating and agitation, the liquid was
separated from the tobacco fiber portion through centrifugation. A
sample of the fibrous solids was then rinsed with water and dried
for 24 h at 35.degree. C. The sample was then tested for lignin
(Kappa number) and Kjeldahl nitrogen content and found to have a
lignin content of 47.145.7% and a Kjeldahl nitrogen content of
0.77-0.80%, exhibiting a reduction of 23.3% to 25.5% (d.w.b) lignin
and a 47.749.9% (d.w.b) Kjeldahl nitrogen from an initial Control 1
content of 61.4% and 1.53% for lignin and Kjeldahl nitrogen,
respectively, as shown in Table I. The fibrous material was then
refined and formed into paper-like sheets on a Fourdrinier type
wire paper making machine. Concentrated extracts as described above
were finally mixed with glycerol and added back to some of the
sheets, as known in the art, before being dried at 90.degree. C.
for 3-5 minutes.
Examples 2A, 2B
[0018] These examples were carried out in a similar manner and with
the same quantities of materials as in Examples 1A, 1B, except that
tobacco materials in alkaline-peroxide solutions were heated to
90.degree. C. and held for 1 h with agitation. Another exception
was that one solution contained 4.2% (w/w) sodium hydroxide and
8.3% (w/w) hydrogen peroxide, while another contained 8.3% hydrogen
peroxide only. The resulting fiber from the alkaline-peroxide
extraction had a 30.5% reduction in lignin and a 62.8% reduction in
Kjeldahl nitrogen, while the peroxide extracted fiber had a 18.6%
and 20.9% reduction in lignin and Kjeldahl nitrogen,
respectively.
Examples 3A, 3B
[0019] These examples were carried out in a similar manner and with
the same quantities of materials as in Examples 1A, 1B, the only
changes being that tobacco materials and solutions were heated to
120.degree. C. and held for 30 minutes. Another change was that one
solution contained 2.5% sodium hydroxide and 7.5% hydrogen
peroxide, while another solution contained 8.3% sodium hydroxide
only. The fibrous materials from the hydroxide treatment gave a
14.5% reduction in lignin and 85.5% reduction in nitrogen, whereas
the alkaline-peroxide treatment gave a 21.8% and 56.2% reduction in
lignin and nitrogen content, respectively.
Control 2 and Examples 4A, 4B
[0020] A 1.9 kg batch of shredded burley stems having a Kjeldahl
nitrogen content of 2.72% was extracted with water at 70.degree. C.
for 30 minutes as known in the art. Following centrifugation, the
liquid extract was either discarded or further treated with an
adsorbent (e.g. diatomaceous clay, activated charcoal, cylodextrin,
or combinations thereof) or absorbent (cellulose acetate), or
passed through a membrane/filters, to remove nitrogenous compounds,
and then concentrated by vacuum evaporation. The resultant washed
fiber, having a 66.4% lignin and 2.25% nitrogen content, was
further extracted to remove lignin and nitrogenous compounds, as
mentioned below. From the washed fibers, 450 g portions were then
loaded into a vessel containing 2.84.2 L of an alkaline-peroxide
solution, comprising either of 5.0% (w/w) potassium hydroxide (KOH)
and 10.0% (w/w) hydrogen peroxide (H.sub.2O.sub.2) or 2.5% (w/w)
KOH and 7.5% (w/w) (H.sub.2O.sub.2). The former alkaline-peroxide
solution containing the tobacco material was then heated to
90.degree. C. and held for 0.5 h, whereas the latter was heated to
120.degree. C. and held for 0.5 h while being agitated. After each
period of heating and agitation, the liquid was separated from the
tobacco fiber portion through centrifugation. Each sample of the
fibrous solids was then rinsed with water and dried for 24 h at
35.degree. C. Each sample was then tested for lignin (Kappa number)
and Kjeldahl nitrogen content. When compared to the washed fiber
Control 2 shown in Table I, the fibrous material treated at
90.degree. C. for 30 minutes had a reduction of 45.2% for lignin
and a >90% for nitrogen, while the material treated at
120.degree. C. had a reduction of 35.8 and >90% for lignin and
Kjeldahl nitrogen, respectively. Concentrated extract as described
above was finally mixed with glycerol and sprayed back on the
shredded fibrous material in a rotating vessel chamber before being
dried at 90.degree. C. for 5-10 minutes.
Control 3 and Examples 5A, 5B
[0021] These examples were carried out in a similar manner and with
the same quantities of materials as in Examples 4A, 4B, except that
shredded flue-cure stem was substituted for shredded burley stem.
The resulting fiber from the alkaline-peroxide (5.0 vs. 10.0%)
extraction at 90.degree. C. for 0.5 h had a reduction of 43.1%
lignin and a >88.8% nitrogen when compared to control 3 values,
shown in Table I. The resulting fiber from the alkaline peroxide
(2.5 vs. 7.5%) extraction at 120.degree. C. for 0.5 h had a
reduction of 38.6% lignin and >88.8% nitrogen when compared to
Control 3 values, shown in Table I.
Control 4 and Examples 6A, 6B
[0022] These examples were carried out in the same manner as in
Example 4 and with the same quantities of materials as in Examples
1A, 1B, the only changes being that a mixture of flue-cure and
burley laminae (17-22 cuts per inch.sup.2) was the staring
material. Other changes included heating vessel contents to
90.degree. C. for 0.5 h, and using alkaline-peroxide solutions
containing either 3.5% NaOH and 6.0% H.sub.2O.sub.2 or 6.0% NaOH
and 11.5% H.sub.2O.sub.2. Resulting fiber from the
alkaline-peroxide (3.5 vs. 6.0%) extraction at 90.degree. C. for
0.5 h had a reduction of 36.6% lignin and 59.7% nitrogen when
compared to Control 4 values, shown in Table I. The resulting fiber
from the alkaline-peroxide (6.0 vs. 11.5%) extraction at 90.degree.
C. fro 0.5 h had a reduction of 43.5% lignin and 69.8% nitrogen
when compared to Control 4 values, shown in Table I.
Control 5 and Examples 7A, 7B
[0023] These examples were carried out in the same manner as in
Examples 4A, 4B, and with the same quantities of materials as in
Examples 1A, 1B, the only changes being that burley lamina (17-22
cuts per inch.sup.2) was the staring material. Another change was
holding extraction vessel contents at 25.degree. C. for 2 h, and
using alkaline-peroxide solution containing 1.25% NaOH and 3.75%
H.sub.2O.sub.2 or heating vessel contents to 70.degree. C. and
holding 0.5 h, and using 2.5% NaOH and 7.5% H.sub.2O.sub.2.
Resulting fiber from the alkaline-peroxide (1.25 vs. 3.75%)
extraction at 25.degree. C. for 2 h had a reduction of 14.5% lignin
and 49.9% nitrogen when compared to Control 5 values, shown in
Table I. The resulting fiber from the alkaline-peroxide (2.5 vs.
7.5%) extraction at 70.degree. C. for 0.5 h had a reduction of
29.2% lignin and 63.5% nitrogen when compared to Control 5 values,
shown in Table I.
Control 6 and Examples 8A, 8B
[0024] These examples were carried out in the same manner and same
quantities as in Examples 7A, 7B, the only changes being that
flue-cure lamina (17-22 cuts per inch.sup.2) was the staring
material. Resulting fiber from the alkaline-peroxide (1.25 vs.
3.75%) extraction at 25.degree. C. for 2 h had a reduction of 16.6%
lignin and 50.4% nitrogen when compared to Control 6 values, shown
in Table I. The resulting fiber from the alkaline-peroxide (2.5 v.
7.5%) extraction at 70.degree. C. for 0.5 h had a reduction of
28.8% lignin and 43.0% nitrogen when compared to Control 6 values,
shown in Table I. TABLE-US-00001 TABLE I Reductions in Kjeldahl
nitrogen and lignin of tobacco extracted with alkaline-peroxide
solutions % (w/w) solution Extraction (dry weight basis) % Kjeldahl
Temp. Temp. Alkali Peroxide nitrogen % Nitrogen % Lignin % Lignin
Starting material (.degree. C.) (min) (NaOH or KOH)
(H.sub.2O.sub.2) (dwb) reduction (Kappa number) reduction Mixed
tobacco materials Control 1 70 30 -- -- 1.53 -- 61.4 -- Aqueously
(ag) extracted material (AE) 1A 70 30 2.5 7.5 0.80 47.7 47.1 23.3
1B 70 120 2.5 7.5 0.77 49.7 45.7 25.5 2A 90 60 -- 8.3 1.21 20.9
50.2 18.6 2B 90 60 4.2 8.3 0.48 62.8 42.7 30.5 3A 120 30 2.5 7.5
0.87 56.2 48.0 21.8 3B 120 30 8.3 -- 0.22 85.6 52.5 14.5 Shredded
Stems Control 2 70 30 -- -- 2.25 -- 66.4 -- Aq. Extracted burley
(RAE) 4A 80 30 5.0 10.0 Bcl* (0.22) 90.2 36.4 45.2 4B 120 30 2.5
7.5 Bcl (0.22) 90.2 42.6 35.8 Control 3 70 30 -- -- 1.98 -- 60.6 --
Aq Extracted flue-cure (FAE) 5A 90 30 5.0 10.0 Bcl (0.22) 88.8 34.5
43.1 58 120 30 2.5 7.5 Bcl (0.22) 88.8 37.2 38.8 Control 4 70 30 --
-- 2.92 -- 61.5 -- Aq Extracted mixed flue-cure/ burley (LAE) 6A 90
30 3.5 6.0 1.18 59.6 39.2 30.6 6B 90 30 6.0 11.5 0.88 69.8 34.7
43.5 Control 5 70 30 -- -- 3.95 -- 62.3 -- Aq Extracted burley
(BLAE) 7A 25 120 1.25 3.75 1.98 49.9 53.3 14.5 7B 70 30 2.6 7.6
1.47 83.5 44.1 29.2 Control 6 70 30 -- -- 2.67 -- 60.4 -- Aq
Extracted flue-cure (FLAE) 8A 25 120 1.25 3.75 1.45 43.8 50.4 16.6
8B 70 30 2.5 7.5 1.13 56.0 43.0 28.8 *BELOW CALIBRATION LIMIT
From the Examples it is seen that a significant reduction of both
lignin and nitrogen is obtained by contacting tobacco with a
mixture of alkali metal hydroxide and hydrogen peroxide from 1% to
5% by weight in a solution and the hydrogen peroxide is from 2.5%
to 12%.
[0025] The foregoing detailed description and Examples are given
primarily for clearness of understanding and no unnecessary
limitations are to be understood therefrom for modifications will
become obvious to those skilled in the art upon reading the
disclosure and may be made without departing from the spirit of the
invention and scope of the appended claims.
* * * * *