MX2010013364A

MX2010013364A - Tobacco treatment.

Info

Publication number: MX2010013364A
Application number: MX2010013364A
Authority: MX
Inventors: Alan Harris; Steve Hemsley
Original assignee: British American Tobacco Co
Priority date: 2008-06-13
Filing date: 2009-05-28
Publication date: 2011-05-30
Also published as: CN102118983B; JP2011522558A; HK1154761A1; AU2009259082A1; CN102118983A; GB0810850D0; KR20110031456A; RU2519905C2; WO2009150444A1; CA2726838A1; CA2726838C; EP2285246A1; BRPI0915087A2; UA101039C2; US20110155152A1; RU2011100109A

Abstract

This invention provides a method for removing undesirable constituents from tobacco which includes extracting tobacco material in an aqueous or organic solvent and filtering the product of the extraction using a horizontal belt filter. The extract and insoluble tobacco residue may be further treated enzymically, chemically or otherwise to remove a complement of undesirable constituents. The extract and insoluble tobacco residue are recombined to form a regenerated tobacco material that is less harmful when combusted than the original material.

Description

TOBACCO TREATMENT DESCRIPTION The present invention relates to the treatment for tobacco and, in particular, to the extraction of selected components of tobacco, for example, in order to reduce certain components of the smoke.

BACKGROUND OF THE INVENTION The tobacco material can be treated and processed to produce a modified mixture which, when burned, generates smoke in which specific components of the smoke have been selectively reduced or eliminated as compared to untreated tobacco. Content ij. Tobacco sugar and nicotine, however, preferably remain essentially unchanged by this process, so that the flavor and smoke properties of the tobacco are maintained. ! ! J In the technical field methods j are known to eliminate or at least reduce the selected components of the tobacco. Such methods may comprise an extraction step in which tobacco material is extracted with an aqueous or organic solvent, a separation step in which the extracted solution is separated from the residue of insoluble tobacco by filtration, 2262. 44 or similar and a treatment step in which the extracted solution is treated to remove specific components. The extracted tobacco extract is then recombined. with the extracted tobacco to ensure that certain components of the tobacco are conserved in the regenerated tobacco material.

U.S. Pat. with the numbers 5,311,886 and 5,601,097 disclose methods for removing tobacco proteins, which involve extracting material i i from tobacco with an aqueous solvent which comprises a surfactant and, optionally, a proteolytic enzyme. The aqueous extract (which comprises components of solubilized tobacco) is separated from the residue of insoluble tobacco and treated to remove any undesirable components, typically including surfactants and polypeptides. The treated tobacco extract is concentrated and recombined in the washed and dried tobacco residue to ensure the retention of certain components, such as flavor components soluble in water and nicotine, in the final product.

U.S. Pat. No. 5,601,097 further describes the sequential extraction of tobacco with a surfactant and a proteolytic enzyme, which may provide a greater reduction in tobacco protein than that observed after only one extraction.; > ' European Patent Publication No. 623 634 extracted, while the fraction comprising the undesirable components is discarded or a part of it is recombined with the extracted tobacco. The regenerated tobacco material thus obtained contains the complete complement of desirable components (such as nicotine), but, is essentially free of undesirable components. nitrates and amines) In the methods described in the Publication of European Patent No. 0 517 407, the tobacco extract is separated from the residue of insoluble tobacco and comes in contact with an extract of additional tobacco that has been obtained by extracting tobacco with a basic solution. The combination of extracts is then applied to the extruded tobacco to form the regenerated product.; ! U.S. Pat. No. 5,243,999 discloses a process in which the tobacco extract is heat treated to cause certain components to crystallize or precipitate out of the solution. The solution extracted alternatively or additionally may come into contact with activated carbon particles-, j to remove additional selected components from the same:. protein thereof, preferably by treating it, with bentonite. The tobacco extract alternatively or additionally can be treated to eliminate: the polyphenols thereof, preferably by treating it; 1 with polyvinylpolypyrrolidone (PVPP).

The process of the invention preferably further comprises the recombination of the extracted tobacco and the treated tobacco extract.

In a second aspect a tobacco product is provided a process of the invention.

In a third aspect of the invention, a smoking article comprising tobacco obtainable by a process of the invention is provided.

BRIEF DESCRIPTION OF THE DIBUJOS! | ! l | Figure 1 illustrates the operating sequence for tobacco extraction and the recycling of the rinse filtrate as the tobacco is transported on a horizontal band filter.

Figure 2 illustrates the operating sequence for the saline rinse of the extracted tobacco using a horizontal band filter. j! j Figure 3 illustrates the sequence of operation for the second saline rinse of the extracted tobacco and the recycling of the rinse filtrate as the tobacco is transported on a horizontal band filter.

Figure 4 illustrates the operating sequence for rinsing fresh tobacco water to remove salt and deactivating the enzyme using a horizontal band filter. j, | Figure 5 illustrates a process for the treatment of tobacco in which the extraction and subsequent rinsing of the tobacco is performed using a plurality of horizontal band filters in series. The tobacco extract and the processed tobacco are then recombined.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES In one embodiment of this invention, the tobacco material to be extracted is tobacco in strips, cut, shredded 1 I or ground. In a preferred embodiment, the tobacco is crushed tobacco. However, other forms of tobacco can be extracted using the methods described herein.

The tobacco material can be mixed with a solvent for extraction to form a mixture. The solvent can be added to the tobacco material nj a ! The ratio between 10: 1 and 50: 1, preferably between 20: 1 and 40: 1 and more preferably between 25: 1 and 30: 1 per weight. In an especially preferred modality, solven! t?; e? it is added to the tobacco material in a ratio of 27: 1 by weight. I i The solvent may be an organic solution, but preferably it is an aqueous solution or it is water. Right at the beginning of the extraction process, the solvent is usually water, but it can also contain alcohols such as ethanol?; Or methanol, or it may contain a surfactant. Other solvents may be used, depending on the specific components to be extracted from the tobacco. ? The mixture can be first formed in a tobacco mixing tank before being pumped to a second tank, such as a piston flow reactor or a continuously stirred tank reactor, to perform the extraction. > The extraction can be carried out at 15-85 ° C, and preferably at 65 ° C. It is preferable that the 1. The mixture is shaken during the extraction, so that the tobacco remains in suspension. The extraction must be done between 15 minutes and two hours. In a preferred embodiment, the extraction is carried out for approximately 20 minutes. 1 ¡j During extraction, the soluble tobacco components are removed from the tobacco material and enter the I solution. These include nicotine, sugars, some proteins, amino acids, pectins, polyphenols and flavors. i i ! ? Applying it to the incoming tobacco residue that travels! on the band at a point upstream. The collection and reapplication upstream of the wash filtrate to the incoming tobacco residue can be repeated several times, preferably three, four or even five times. Therefore, the final wash filtrate that is collected at the head of the band can be concentrated on those soluble tobacco components that have been removed from the 1 tobacco residue when traveling through the filter.

An outline of the sequence of operation will stop the 'i! Tobacco extraction and recycling of the wash filtrate as the tobacco travels through the horizontal band filter is shown in Figure 1.

The final wash filtrate can be further recycled by adding fresh tobacco from a tobacco mixture, ready for extraction. For example impale, the final wash filtrate can be added to the interior of the tobacco mixing tank where a tobacco mixture is formed prior to extraction.

The extraction process can therefore be a continuous process in which fresh tobacco is extracted using recycled washing filtrate. Only at the beginning of the extraction process is the tobacco extracted with fresh solvent. Once the extraction process has started, fresh solvent is not used in the extraction, but the solvent is formed only with filtered 'recycled washing.; ! As the extracycling process continues, the extract becomes more concentrated in components of soluble tobacco. These components include those that entered the solution during the primary extraction in the extraction tank (forming the mother filtrate), as well as those that entered the solution during the secondary extraction on the horizontal band filter (forming the wash filtrate) . j t Therefore, the final filtrate comprises both the mother filtrate and the wash filtrate. In doing so, the resulting tobacco residue after filtering lacks those soluble components in the solvent used for the extraction.

The extracted tobacco can be filtered, to eliminate any of the same. The extracted tobacco that emanates from the horizontal band filter is typically in the form of a dehydrated layer.

The final filtering, which will be referred to hereinafter as the tobacco extract, can subsequently be processed to eliminate those undesirable components in the final tobacco product. The components 1 undesirable include proteins, polypeptides, amino acids, polyphenols, nitrates, amines, nitrosamines and pigment compounds. The levels of desirable components such as > Sugar and nicotine, however, must remain unaltered so that the taste and smoking properties of the extracted tobacco are comparable to those of the original material.

In a preferred embodiment, the tobacco extract is treated to remove the proteins, polypeptides and / or amino acids. Up to 60% of the proteins contained in the original tobacco material can be removed using an insoluble adsorbent such as hydroxyapatite or a mineral ! I! Fuller's earth as attapulguite or bentonite. , The tobacco extract is preferably treated with bentonite, to remove the polypeptides thereof. Bentonite can be added to the extract in an amount of 2 in approximately 64 kg of water (quantities per hour), for example, 7.13 kg of bentonite in 64.18 kg of. water (quantities per hour). In any case, the concentration of bentonite should be high enough to substantially reduce the protein content of the tobacco extract, but not so high that it additionally adsorbs nicotine therefrom.

The treatment with bentonite can also be effective in the elimination of pigment compounds I found in the tobacco extract which, yes; they are not eliminated, they tend to darken the extract after concentration. When enough bentonite is used to treat the extract, the reduced amount of pigment compounds can result in a product that is not too dark in appearance.

After the treatment with bentonite, the Tobacco extract can be purified from the extract by centrifugation and / or filtration.

The tobacco extract may also, or alternatively, be treated to remove the polyphenols therefrom. Polyvinylpolypyrrolidone (PVPP) is an insoluble adsorbent for polyphenols, traditionally used in the beer industry to remove polyphenols from beer. The PVPP in an amount of 5 to 10% of the weight of the tobacco extracted initially can be added to the extract. This amount of PVPP can eliminate between 50 and 90% of the polyphenols in the solution! It is considered that the optimum pH for the elimination of polyphenols from tobacco extract by PVPP is close to 3. The efficiency of adsorption by PVPP for! so much i! it can be increased by reducing the pH of the extract through the addition of a suitable acid, such as hydrochloric acid.

As an alternative to using PVPP to adsorb the polyphenols, one or more enzymes can be added to the tobacco extract to degrade the polyphenols inside it. A suitable enzyme is laccase (urishiol oxidase).

However, the invention is not limited to methods for removing only proteins and / or polyphenols from tobacco. Alternative or additional enzymes, agents or adsorbents can be used to eliminate other undesirable components of the tobacco extract. Some examples of additional undesirable tobacco components that may be eliminated from the extract include nitrates, amines and nitrosamines.

If a plurality of components of the tobacco extract is removed, several tanks can be configured in series, each comprising a different enzyme, agent or adsorbent, in order to eliminate a complement of undesirable components chosen. Alternatively, a single tank can contain a plurality of enzymes, agents or adsorbents so that undesirable constituents can be removed in a single step. For example, a pancake containing bentonite or PVPP may comprise one; 6 more enzymes, agents or additional adsorbents to eliminate not only the proteins or phenols of tobacco, but also one or i more of the additional undesirable components.

After the treatment of the tobacco extract 1 to remove the undesirable components selected, the extract is preferably concentrated at a solids concentration between 20 and 50% by weight. Concentrations of up to 10% solids are achieved! more efficiently using reverse osmosis. An additional concentration of about 40% solids can be achieved by a downflow evaporator. Other methods of concentration known to a person skilled in the technical field can be used.

The concentrated tobacco extract! it can then recombine with the extracted tobacco.

The tobacco, having been extracted in an aqueous solution as discussed above, however, is preferably extracted to remove one or more undesirable components before being recombined with the i Concentrated tobacco extract 1 Additional extraction of tobacco can be done using a specifically selected enzyme! to eliminate the chosen component. 1 In a chosen embodiment, the enzyme is a proteolytic enzyme for removal of tobacco protein. The enzyme is preferably a bacterial or fungal enzyme and, more preferably, is an enzyme used commercially in the food and detergent industries. The enzyme can be selected from the group consisting of Savihase ™, ! i! I I Neutrase ™, Enzobake ™ and Alcalase ™, all of which are available from Novo Inc.

The proteolytic enzyme is preferably added to tobacco in an amount between 0.1 and 5% by weight of the material Tobacco solution to the materi preferably between 20: 1 and 40: 1 and more preferably between 25: 1 and 30: 1 by weight. In a particularly preferred embodiment, the ratio of water to tobacco is 27: 1 by weight.

The pH of the tobacco / enzyme mixture should be the one that promotes the optimal enzymatic activity. Accordingly, it may be convenient to feed the dehydrated tobacco layer emanating from the first horizontal band filter to a tank in which the pH is adjusted, for example, by the addition of a base such as sodium hydroxide. The pH adjusted tobacco can then be fed into an enzyme feed tank to mix with the chosen enzyme. The tobacco / enzyme mixture can then be fed to a plug flow reactor, where the extraction of enzymes is carried out.

The extraction of enzymes should be carried out at the temperature that promotes the optimal enzyme activity. Preferably, a narrow temperature range, such as 30-40 ° C, should be used to avoid denaturing the enzyme.

The optimal working conditions when Savinase ™ is the chosen enzyme are 57 ° C and pH 9-11. i.

The extraction of enzymes should be done for at least 45 minutes; any shorter duration is considered insufficient for the degradation of a proteolytic enzyme to degrade tobacco proteins.

Of course, they can be done; several extractions of enzymes if there are several components to be eliminated from tobacco. These can be performed in series or several enzymes can be added to the tobacco in a single treatment step.; , It is also still possible for the enzyme to be included in the first extraction step in the treatment process, instead of forming a separate extraction step.

After extraction of enzymes, the tobacco / enzyme mixture can be fed to a second horizontal band filter and the mother filtrate can be collected and treated as waste. The insoluble tobacco residue can be washed with a saline solution, preferably a I. ' sodium chloride solution, to rinse it free of enzymes. The saline rinse can be carried out sequentially upstream, similar to that used in the extraction of tobacco in the first band filter. 1 ? horizontal.

Thus, the saline solution may be applied to the tobacco towards the end of the filter. The filtered lavadd. Can be recycled and used to wash the tobacco residue that travels on the strip at a point upstream. The upstream collection and reapplication of the wash filtrate to the incoming tobacco residue can be repeated several times, preferably three, four or even five ! , 1 times The wash filtrate collected at the head of the band is treated as waste. This is illustrated in Figure 2.

Tobacco rinsed with saline; can be squeezed at the end of the band, to eliminate any surplus liquid from it.

The tobacco can then be fed to a saltwater mixing tank and a piston flow reactor or to a continuous stirred tank reactor to be combined with a saline solution in a second salt rinse.

The mixture can then be fed !, to a third horizontal band filter and to the filtrate I've collected. This filtrate is treated as waste and is not recycled. A fresh saline solution, preferably a sodium chloride solution, can be applied to the tobacco towards the end of the filter. As before, the wash filtrate can be recycled and used to wash the tobacco residue traveling over the band at a running point 'i above. The collection and reapplication upstream of the :? Washing filtrate to incoming tobacco residue 1 can be repeated several times, preferably three, four or even five times. The final wash filtrate collected at the head of the band can be recycled and used in the first saline rinse. This is illustrated in Figure 3.

The tobacco rinsed with saline solution can be squeezed at the end of the band, to eliminate any surplus of water from it. Next it is combined i i! preferably with a fresh batch of salt water to ensure its almost complete elimination of the tobacco enzyme as much as possible. A mixing tank and a piston flow reactor or a continuous stirred tank reactor can be used for this purpose. ! In order to eliminate the salt of the rinsed tobacco with saline, a rinsing with clean water can be carried out. Tobacco rinsed with saline can be fed into the band of a fourth band filter. horizontal and mother filtrate collected and recycled for use in the first or second saline rinse. Fresh water can then be applied to the end of the band tobacco. The wash filtrate can be recycled and used to wash the tobacco residue traveling over the band at a point upstream. The upstream collection and reapplication of the wash filtrate to the incoming tobacco residue can be repeated several times, preferably three, four or even five times. The final wash filtrate collected at the head of the band should be returned to a reservoir serving 1 each of the salt water rinses. This is illustrated in Figure 4.

Rinsing with salt and water, however, may not be enough to remove all enzymes from tobacco.

It is important that the enzymatic activity for the operator of associated with the enzyme in the finished product.

The rinsed tobacco can therefore be treated to deactivate any residual enzyme remaining in the tobacco after rinses with salt and water. This can be done by treating the tobacco with steam enough to deactivate the enzyme, but not so much that the tobacco loses its fibrous edema. In one embodiment, the steam treatment is ! :! perform at 98 ° C for four minutes, but the residence time can be increased to approximately 10 minutes if desired. Alternatively, the tobacco can be heat treated to deactivate the enzyme, for example by microwaveing or baking. In another embodiment, the enzyme can be deactivated by chemical denaturation, however, steps must be taken to remove the chemical from the tobacco.

If the tobacco is treated by steam, this can be done while the tobacco is approaching the extremity of the fourth horizontal band filter, as shown in Figure 4. The excess liquid can be removed from the tobacco by squeezing it. ¡J.

Thus, the process may comprise a series of separate steps, one or more of which may be performed using a horizontal band filter. Ert a modality, all the steps of the process are carried out using a horizontal band filter. The process can therefore be a continuous process in which fresh tobacco is continuously fed to a first filter of: horizontally and the processed tobacco is continuously produced downstream. In one embodiment, the steps of tobacco extraction, saline rinsing and enzyme deactivation are each carried out on a horizontal band filter and the multiple filters can be distributed in series for this. end. This is illustrated in Figure 5. i j The tobacco treated below can be further processed making it suitable for recombination with the tobacco extract. In a preferred embodiment, the tobacco is fed to a discharger which decomposes the tobacco layer into free flowing fibers The processed tobacco can then be recombined with the concentrated tobacco extract. Adding the treated extract back to the extracted tobacco assures the retention of the soluble taste components of the tobacco water and nicotine in the final product. Therefore, recombination results in a product of! tjabaco that has a physical shape and appearance, taste and smoking properties similar to the original material; but ! 1í with substantially reduced levels of protein, polyphenols or other chosen components. j, i Recombination can be achieved by spraying the tobacco extract on the tobacco. The amount of the original extract recombined with the processed tobacco depends on the amount lost during the treatment of the extract to eliminate the selected components, and will vary from one type of tobacco to the next.

A standard drying process can be used; to dry the tobacco, either before, during or after recombination with the treated tobacco extract. He The initial moisture content of the tobacco typically is about 70-80%. In a preferred embodiment, the moisture content after drying should be about 14%. : 'Í1 A heat dryer, such as a dryer; for aprons, can be used to reduce the initial moisture content in tobacco to approximately 30%. A second heat heater, such as an air dryer, can then be used to further reduce the moisture content to about 14%.

The final dry product can be subsequently processed into a finished form, such as a leaf, which, when crushed, can form all or part of the filling i I of a cigarette. t 1 Because as much as 30% of the original components of tobacco are removed from it during the extraction and treatment process, however, the concentration of the remaining components per unit weight of tobacco is increased in the finished product in :? comparison to the original material. These components include cellulose, which, along with sugars and starches, can produce harmful volatile materials such as acetaldehyde and formaldehyde in the smoke when burned.

To compensate for the above, a special type of filter can be included in a smoking article that i í |; contain the treated tobacco. The US Patent: No. 4,033,361 discloses a suitable filter, which contains a macroporous ream of the ammo type with anion exchange containing essentially only primary amino groups, as an adsorbent for volatile tobacco smoke components. Carbon can also be included in the filter.

Claims

1. A process for the treatment of tobacco, which comprises extracting tobacco with an aqueous or organic solvent and filtering the product from the extraction, where both the extraction and filtration steps are carried out on a horizontal band filter. . ij

2. A process according to claim 1, wherein the extracted tobacco is fed continuously onto the horizontal band filter and the extraction and filtration steps are continuously carried out as the tobacco is transported along the filter.

3. A process according to claim 2, wherein the filtrate is recycled and used as a solvent in the extraction of the tobacco fed into the horizontal band filter.

4. A process according to claims 1-3, which also

5. A process according to claim 4, wherein the enzyme is a proteolytic enzyme.

6. A process according to claim 4 or 5, which further comprises rinsing the tobacco treated with enzymes with a saline solution.

7. A process according to claim 6, in i;] wherein the saline rinsing step is performed on a horizontal band filter.

8. A process according to claim 6, wherein the enzyme-treated tobacco is rinsed twice with a saline solution.

9. A process according to claim 8, wherein the two steps of salt rinsing are performed on horizontal band filters separately.

10. A process according to claim 7 or 9, wherein the saline rinse is performed continuously as the tobacco is transported through the filter (s).

11. A process according to claim 10, wherein the filtrate from the second salt rinse is recycled and used as a saline solution in a first saline rinse of tobacco fed to the first horizontal strip filter for saline rinse.

12. A process according to the claims; 4-11, which also comprises deactivating the enzyme in tobacco.

13. A process according to claim 12, wherein the deactivation is carried out by treating the tobacco with steam, thermally or chemically.

14. A process according to claim 13, wherein the deactivation is carried out on tobacco on a horizontal band filter.

15. A process according to any of claims 1-14, made using several filters, of horizontal band in series. ,!

16. A process according to claim 1, which comprises: 1! (a) extract tobacco with an aqueous or organic solvent, - (b) treat the tobacco with an enzyme; (c) rinsing the enzyme-treated tobacco with a saline solution; Y (d) deactivating the enzyme in tobacco; wherein one or more steps (a) to (d) are performed on a horizontal band filter. |

17. A process according to any of claims 1 to 16, which further comprises treating the tobacco extract obtained from the extraction of tobacco; to eliminate the protein from it.

18. A process according to claim 17, wherein the tobacco extract is treated with bentonite. : !!

19. A process according to either of. claims 1 to 18, which further comprises treating the tobacco extract obtained from the extraction of tobacco! to eliminate polyphenols from it.; ¡¡

20. A process according to claim 19, in : Where the tobacco extract is treated with polyvinylpolypyrrolidone (PVPP). ? !

21. A process according to either of. . Claims 17-20, which also comprises the recombination of the extracted tobacco and the extract of; Abacus treated.

22. Tobacco obtainable by a process: I according to any of the claims 1-21.

23. A smoking article comprising the tobacco claimed in clause 22.