Commonwealth of Australia Patents, Trade Marks and Design Acts Verification of Translation RWS Group Ltd, of Europa House, Marsham Way, Gerrards Cross, Buckinghamshire, England, state the following: One of its translators is fluent in both the English and German languages and capable of translating documents from one into the other of these languages. The attached document is a true and complete English translation to the best of its knowledge and belief of International PCT Application No. PCT/EP2004/005906 as filed on June 01, 2004. Date: 13 December 2005 Signature: S. ANTHONY Director For and on behalf of RWS Group Ltd 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 5 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, 10 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 15 "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. 20 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. 25 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, 30 such as N'-nitrosonornicotine (NNN), nitrosonornicotine ketone or 4-(methylnitrosoamino)-l-(3-pyridyl)-1 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 35 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, - 2 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 5 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 10 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 15 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 0 C and for from about 0.5 to 6 hours, 20 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 25 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 30 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. 35 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 - 3 Blend cigarette, a tobacco mixture having the features of Claim 1, namely a tobacco mixture of the American Blend type which is characterized in that all, or the majority (i.e. more than 50%), of the Burley tobacco is 5 present as cut reconstituted tobacco sheet which has been obtained using the TSNA adsorption process, is proposed for achieving the object. Advantageous embodiments of the invention ensue from the remaining claims. 10 Preference is given to at least 60% by weight of the Burley tobacco in the reconstituted tobacco sheet consisting of the lamina of the Burley tobacco. Within the context of the present invention, other air-cured 15 dark tobaccos, such as "Maryland" or "Geudertheimer", are also considered to be Burley tobacco. Preference is given to the reconstituted tobacco sheet having been impregnated with odiferous substances, 20 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 25 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 30 offered to the smoker as 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 factory-produced cigarette. 35 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 - 4 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, 5 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. 10 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. 15 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 20 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 25 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 30 examples. Example 1 Filter cigarettes were produced from an American Blend 35 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 - 5 their content of tobacco-specific nitrosamines, were determined. The entire content of 40% by weight of Burley and 5 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 10 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. 15 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 20 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. 25 An independent panel judged the cigarettes according to the invention to be equivalent to the comparison cigarettes in regard to taste and other properties.
- 6 Table I Compar TSNA- Reduc ison reduced tion [%] Burley + Maryland [%] 40 0 Burley + Maryland TSNA-red. [%] 0 40 Virginia [%] 48 48 Oriental [%] 12 12 Strand weight mg 756 762 Draw resistance Pdc daPa 117 113 Open draw resistance Pdo daPa 100 98 Filter ventilation % 17.9 17.1 Hardness [mm impression depth] mmI 1.89 1.94 Nicotine % 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 - 7 Example 2 Filter cigarettes were produced from an American Blend 5 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 10 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 15 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. 20 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 25 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 30 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 35 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 - 8 46% in the case of NNN and with nicotine being reduced by 12%. An independent panel judged the cigarettes according to 5 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 [%] reduced [%] Burley [%] 29 0 11 Burley TSNA-red. [%] 0 29 18 Virginia [%] 63 63 63 Oriental [%] 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 10