Note: Descriptions are shown in the official language in which they were submitted.
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Tobacco mixture and a cigarette comprising it
The invention relates to a tobacco mixture of the
American Blend type having a content of up to 70% by
weight of Virginia tobaccos, up to 40% by weight of
Burley tobaccos, up to 20% by weight of oriental
tobaccos and up to 5% by weight of other tobacco
varieties, with it being possible for up to 60% of
these tobaccos to be present as expanded tobacco, and,
in addition, to a cigarette which comprises this
tobacco mixture.
While the content of Burley tobaccos in these tobacco
mixtures contributes to augmenting the aroma and the
"character" of the cigarette, it has the disadvantage
that the content of nitrosamines is increased, both in
the mainstream smoke and in the side-stream smoke, very
much more than it is by the other tobacco varieties in
an American Blend cigarette.
The object of the invention is to decrease the content
of nitrosamines in tobacco mixtures of the American
Blend type and in the cigarettes which are produced
from these mixtures.
Apart from what are termed the volatile nitrosamines,
such as N-nitrosodimethylamine, which are formed, by
pyrolysis, in nanogram quantities only, when a
cigarette is smoked, the tobacco-specific nitrosamines,
such as N'-nitrosonornicotine (NNN), nitrosonornicotine
ketone or 4-(methylnitrosoamino)-l-(3-pyridyl)-l-
butanone (NNK), N'-nitrosoanatabine (NAT) and N'-
nitrosoanabasine (NAB), which occur in an order of
magnitude of up to 10 pg in the mainstream smoke and in
an about 4- to 10-fold quantity in the side-stream
smoke, are to be regarded as being unwanted.
Since the tobacco-specific nitrosamines, termed TSNAs
below, are predominantly present in the Burley tobacco,
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the invention is based on only removing the
nitrosamines from this fraction of the tobacco mixture,
with this fraction then, while retaining its taste
"character", yielding, together with the other tobacco
components, an American Blend cigarette whose taste is
unchanged.
WO 02/28209 Al discloses a method which can be used to
remove the TSNA, by adsorption, from a solution of
solvent-treated tobacco, with it being possible for the
solution, which has been freed from, or depleted in,
TSNA, either to be used for producing reconstituted
tobacco or to be added, as an aroma component, to the
insoluble tobacco residue or to any optional tobacco
mixture. In detail, the procedure adopted in this
method, which is termed the TSNA adsorption method
below, is as follows: the tobacco, for the most part
ribs or tobacco waste, is extracted, at temperatures of
from 10 to 100 C and for from about 0.5 to 6 hours,
with a solvent which principally consists of water;
after that, the solution which has been separated from
the tobacco material is concentrated and brought into
contact with a TSNA-accepting adsorbing agent, such as
active charcoal or zeolite, in a quantity of from 5 to
50% by weight based on the quantity of extract. After
the adsorbing agent has been separated off, all or part
of the extract, which has been freed from TNSA, is
loaded onto the extracted tobacco material, which is
processed, where appropriate, by means of a paper
production process, e.g. in accordance with
US 4,182,349, or using a casting process, e.g. in
accordance with US 4,674,519, into a sheet of
reconstituted tobacco.
Proceeding from the abovementioned basic concept of
only removing the tobacco-specific nitrosamines from
the Burley fraction in the tobacco mixture, in order,
while retaining its taste "character", to obtain,
together with the other tobacco components, an American
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Blend cigarette. The present invention provides a tobacco mixture of
the American Blend type having a content of up to 70% by weight of
Virginia tobaccos, up to 40% by weight of Burley tobaccos, up to 20%
by weight of oriental tobaccos and up to 5% by weight of other tobacco
varieties characterized in that all, or the majority, of the Burley tobacco
is present as cut reconstituted tobacco sheet which has been obtained
using the TSNA adsorption method.
Preference is given to the reconstituted tobacco sheet having been
impregnated with odiferous substances, flavouring agents and/or
aromatizing substances either during and/or after its production.
The best results are achieved when the reconstituted tobacco sheet has
been produced using a paper producing process, with this sheet then
having been impregnated with the extract, or parts thereof, which has
been obtained by means of the TSNA adsorption method.
The tobacco mixture according to the invention can be offered to the
smoker as a fine-cut tobacco, which he can use for making cigarettes
himself, as pipe tobacco or else as a cigarette-like smoking product
and, in particular, as a factor-produced cigarette.
Surprisingly, it has been found that combining the TSNA adsorption
method, which is exclusively used for the Burley component of the
American Blend mixture, with the production of a reconstituted tobacco
based exclusively on Burley tobacco, in connection with which
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an essentially pure Burley tobacco sheet is
consequently obtained, results in a tobacco mixture
which, on the one hand, corresponds in taste to the
customary American Blend type and, on the other hand,
exhibits a substantially lower content of TSNA in the
mainstream smoke and the side-stream smoke, with a
slight decrease in the nicotine content also occurring
as an advantageous side-effect.
This surprising effect is obtained, in particular, when
the majority, for example more than 60% by weight, of
the Burley tobacco which is used consists of lamina,
that is to say, the content of ribs and/or minor
components is kept low.
Apart from the fact that all the other parameters of
the American Blend tobacco mixture according to the
invention, such as ash content, tobacco pH, acid number
and also strand weight and draw resistance in a
cigarette, are virtually unchanged as compared with an
untreated American Blend tobacco mixture, the
application of the TSNA adsorption method to the
content of up to about 40% by weight of Burley tobacco
in an American Blend tobacco mixture, and the use of a
pure Burley tobacco sheet from which TSNA have been
removed, is very much more economical than treating the
entire tobacco mixture with the TSNA method.
The invention is explained below with the aid of
examples.
Example 1
Filter cigarettes were produced from an American Blend
tobacco mixture composed of 40% by weight of Burley and
Maryland tobaccos, 48% by weight of Virginia tobacco
and 12% by weight of oriental tobacco and their
physical data, their smoke and tobacco contents, and
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their content of tobacco-specific nitrosamines, were
determined.
The entire content of 40% by weight of Burley and
Maryland tobaccos had been prepared, in analogy with
Example 4 in WO 02/28209 Al, by means of the TSNA
adsorption method, using water as solvent and using
active charcoal as adsorbing agent, with the
reconstituted tobacco sheet, which had been obtained by
means of the paper producing process, being processed
into cut tobacco. Filter cigarettes composed of the
same American Blend tobacco mixture in which
conventional Burley and Maryland tobaccos had been used
served for comparison.
The values in Table I below show that the tobacco-
specific nitrosamines were reduced substantially in the
cigarettes according to the invention, with the
reduction amounting to up to 74% in the case of
individual substances such as NAB/tobacco. The content
of nicotine in the smoke/tobacco is also noticeably
reduced whereas the physical data are virtually
unchanged as compared with those of the comparison
cigarettes.
An independent panel judged the cigarettes according to
the invention to be equivalent to the comparison
cigarettes in regard to taste and other properties.
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Table I
Compar TSNA- Reduc-
ison reduced tion
L~]
Burley + Maryland [%] 40 0
Burley + Maryland TSNA-red. [%] 0 40
Virginia [o] 48 48
Oriental [o] 12 12
Strand weight mg 756 762
Draw resistance Pdc daPa 117 113
Open draw resistance Pdo daPa 100 98
Filter ventilation o 17.9 17.1
Hardness [mm impression depth] mml 1.89 1.94
Nicotine o dry weight 1.89 1.46 23
Nitrate % d.b. 1.04 1.18
Chloride % d.b. 0.62 0.71
Reducing substances % dry weight 8.7 8.8 -1
Inv. sugar % dry weight 2.0 1.9 5
Ash % dry weight 15.8 15.3 3
Tobacco pH 5.8 5.8 0
NNN / tobacco Pg/g 6.2 1.8 71
NAT / tobacco Pg/g 2.3 0.8 66
NAB / tobacco Pg/g 0.1 0.0 74
NNK / tobacco Pg/g 1.4 0.4 70
TSNA / tobacco Pg/g 9.9 3.0 70
NNN / smoke ng/cig. 290 85 71
NAT / smoke ng/cig. 145 52 64
NAB / smoke ng/cig. 16 5 68
NNK / smoke ng/cig. 214 63 71
TSNA / smoke ng/cig. 665 205 69
Nicotine / smoke mg/cig. 0.84 0.68 19
Smoke pH 6.64 6.56 1
Condensate mg/cig. 11.2 11.1 1
Draw number 7.7 7.5 3
CO mg/cig. 11.7 12.4 -6
CO / condensate 1.0 1.1 -7
NO pl/cig. 171 179 -5
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Example 2
Filter cigarettes were produced from an American Blend
mixture composed of 29% by weight of Burley tobacco,
63% by weight of Virginia tobacco and 8% by weight of
oriental tobacco. In one experimental series 2a, a
Burley tobacco which had been reduced by means of the
TSNA method, as described in Example 1, was used, as a
cut reconstituted sheet, for the entire 29% by weight
content of Burley tobacco while, in another
experimental series 2b, the majority of the Burley
tobacco, namely with a content of 18% by weight,
consisted of this TSNA-reduced tobacco with the
remainder, namely with a content of 11% by weight,
consisting of conventional Burley tobacco. Once again,
an American Blend mixture of the above composition in
which the entire content of Burley tobacco was
conventional served for comparison.
Table II below lists the compositions of the American
Blend tobacco mixtures containing TSNA-reduced or
partially TSNA-reduced Burley tobaccos, including that
of the comparison mixture, and also their tobacco-
specific nitrosamine values in the tobacco, together
with the respective percentage reductions.
The table shows that there was a marked reduction in
the tobacco-specific nitrosamines, by up to 51% in the
case of the individual substance NNN, and an 18%
reduction in the nicotine in the tobacco, in the case
of the mixture containing Burley tobacco which was
fully treated by the TSNA method. In the case of the
American Blend mixture which contained Burley tobacco
which had only for the most part been treated by the
TSNA method, with the remainder consisting of
conventional Burley tobacco, reduced TSNA values are
obtained, with this reduction being in some cases
correspondingly less, with the reduction amounting to
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46% in the case of NNN and with nicotine being reduced
by 12%.
An independent panel judged the cigarettes according to
the invention to be equivalent to the comparison
cigarettes in regard to taste and other properties.
Table II
Compar- 2a Reduc- 2b Reduc-
ison TSNA- tion TSNA- tion
reduced [o] reduced [o]
Burley [o] 29 0 11
Burley TSNA-red. [ s] 0 29 18
Virginia [o] 63 63 63
Oriental [o] 8 8 8
NNN / tobacco 1.07 0.53 51 0.58 46
NNK / tobacco 0.75 0.51 32 0.55 28
NAB / tobacco 0.08 0.05 32 0.05 32
NAT / tobacco 0.70 0.59 16 0.60 15
TSNA / tobacco 2.58 1.65 36 1.76 32
Nicotine / tobacco 2.09 1.72 18 1.83 12
