EP0242271B1 - Process for preparing flavoured reconstituted tobacco, and flavoured reconstituted tobacco obtained by this process - Google Patents

Abstract

An improvement to the papermaking process for reconstituting tobacco, in which the strong liquor is aromatised by fermentation with a yeast before being employed for reimpregnating the base sheet, and the aromatised reconstituted tobaccos obtained by this process. After tobacco fragments have been kept in aqueous solution in a digester (10, 11), the strong liquor is separated from the fibres in a press (12), and the fibres are then treated separately to form a base sheet. <IMAGE>

Description

The present invention relates to a process for the preparation of reconstituted tobacco, flavored by fermentation, and the flavored reconstituted tobacco obtained by this process and the tobacco mixtures comprising it.

When making cigarettes, only part of the tobacco leaf is used, the blade. The ribs (or ribs) are removed by threshing or peeling. The leaf is then chopped into strands (or scaferlatis). These treatments are the source of debris called dust, debris, or "scraps" and ribs according to their size and origin. They represent up to 20% of the initial mass of tobacco and can be recycled and reintroduced into cigarettes in the form of reconstituted tobacco.

The reconstitution consists in transforming this debris into a sheet which is then chopped and reincorporated in the tobacco tobacco mixtures or used as an envelope for cigars (undercoats and capes).

This sheet can be obtained by grinding, attrition or disintegration of the debris and then mixing with a binder and various additives (reinforcing fibers, fungicides, humectants, flavors, various fillers), spreading the paste obtained on an endless metal strip, drying , winding and, if necessary, splitting of the sheet in the form of strips.

Numerous reconstitution methods are known, for example, stratification methods, solvent evaporation methods, impregnation methods or extrusion methods. The reconstituted tobacco resulting from these first four processes is used in general for the manufacture of undercoats and cigar wrappers.

For the production of leaflets intended for mixtures of tobacco for cigarettes, a papermaking process for reconstituting tobacco is most often used, of which FIG. 1 gives the conventional diagram. According to such a method, tobacco debris from threshing or chopping the leaves is collected and after sieving, mixed with water, for example in a digester 1, which makes it possible to extract the water-soluble products. The soluble products are then separated from the insoluble, for example, by passing the pulp obtained through a screw press 2. In such a papermaking process, the insoluble products are therefore dissociated from the soluble products in order to treat them separately. The fibers pass, for example, through a refiner 3 before passing through a paper machine 4 to form a sheet of tobacco fibers or base sheet.

The products soluble in aqueous solution from the pressing, that is to say the strong liquor, are concentrated, for example, in a vacuum evaporation device 5, before being reincorporated in the base sheet to form a reconstituted leaf. The reconstituted sheet is then treated in a drying device 6.

This reconstituted tobacco leaf will then be cut into sheets similar to tobacco strips which are reintroduced into tobacco tobacco mixtures.

Usually, to flavor tobacco, "sauces" or "tobacco juice" are introduced during manufacture.

These sauces may include humectants, such as glycerin or propylene glycol, sugars, such as glucose or invert sugar, flavorings, such as cocoa, licorice or fruit extracts, or synthetic flavorings or additives.

In certain conventional processes, the flavoring is carried out for example by spraying "sauces" before or after the drying of the tobacco. In a process for manufacturing reconstituted tobacco, these sauces or juices are added to the impregnation liquor. The major drawback of these sauces or juices comes from the fact that substances foreign to tobacco, and therefore taste properties, are introduced into tobacco "notes" which are not identical to those of tobacco.

In another known aromatization process described in the publication FR-A-2 354 716 (which corresponds in particular to the publications GB-1 520 234, AU-2 353 977, EUA-4135 521, JP-52156999, CA-1 074 986), a flavoring liquor was introduced into the tobacco which was obtained by fermentation of a tobacco suspension to which a high proportion of sugar was added (20 kg of sugar per 10 kg of tobacco), then filtration of the suspension after fermentation, and possibly concentration of the filtered suspension.

The application of this technique to the flavoring of a reconstituted tobacco leaf would therefore consist in adding to said strong liquor defined above a flavoring liquor which would not be any but which would have been prepared in accordance with the teachings of the publication FR-A -2,354,716.

Such a flavoring process is also not satisfactory, neither technically nor in terms of profitability.

The present invention aims to also use fermentation to improve the aroma of tobacco but avoiding the aforementioned drawbacks.

This is achieved, according to the invention, by directly fermenting the strong liquor using yeast, without requiring the addition of sugar and without requiring the addition of a flavoring liquor to the strong liquor.

The invention thus provides a process for the preparation of flavored reconstituted tobacco from tobacco particles in which these particles are mixed with water to obtain, on the one hand, an aqueous solution (called "strong liquor") containing the water-soluble products. tobacco particles and, on the other hand, insoluble products, the strong liquor is separated from the insoluble products, the strong liquor is concentrated, sheets are made from said insoluble products and said concentrated strong liquor is incorporated into said leaves so to obtain, after drying, reconstituted tobacco leaves, characterized in that before concentration, said seed is sown strong lacquer with yeast and the yeast is removed after fermentation.

"Tobacco particles" are called parenchyma debris, and / or fragments of ribs or ribs and / or tobacco dust produced during the various manipulations and treatments during the transformation of the natural tobacco leaf into a smoking product. .

In a manner known per se, the strong liquor can be subjected to other treatments to remove constituents deemed undesirable, but these other treatments which are not concerned by the present invention will not be described.

It should be noted here, however, to avoid any confusion, that fermentation has also been recommended to remove unwanted constituents from tobacco; this is the case for example of the publication EP-A-0 024 152 (or CA-1 129 357 or US-4 622 982) which recommends the fermentation of tobacco, under very specific conditions, to reduce the level of certain compounds containing nitrogen, but it is neither reconstituted tobacco nor improving tobacco flavor. This is also the case for publication FR-A-2 419 034 (or GB-1 557 253 or US-4 308 877) which recommends a fermentation technique to reduce the nitrate content and of publication EP-A- 0070112 (or CA-1 191 673) which also recommends denitrification by the use of microorganisms.

It will thus be noted that microorganisms have also been used to reduce the content of other components in tobacco, such as nicotine (FR-A-2 437 794, US-4 140 136, US-4151 848).

The method according to the invention makes it possible to flavor the sides, in particular the parts of the leaves which are usually without aroma relative to the parenchyma of the leaves and therefore to enhance these parts, and this without introducing notes foreign to the notes of tubac himself.

The function of the yeast with which the strong liquor is sown is, on the one hand, to compete with the undesirable contaminating natural flora, on the other hand, to use the assimilable substrates contained in the strong liquor, mainly reducing sugars, to produce components. flavorings.

The yeasts used preferably come from strains chosen from the genera Candida, Kluyveromyces or Saccharomyces, for example, from Candida Pseudotropicalis, Candida utilis, Kluyveromyces fragilis, Saccharomyces diastaticus, Saccharomyces cerevisiae, preferably Kluyveromyces fragilis and Saccharomyces cerevisiae, selected for their good flavoring of the strong liquor without nutrient supply, and their heat resistance, necessary during the process.

These yeasts can come from cultures of strains in a synthetic medium or from the recycling of yeasts at the end of a previous fermentation.

The strong liquor, before sowing, should preferably have a refractometric index of between 1% and 15%, preferably between 4% and 12%, its initial sugar concentration should preferably be between 5 and 20 g / l.

In general, the strong liquor, with a view to its flavoring, can be fermented without adding any external component, although these may be useful under certain particular conditions.

This strong liquor is seeded with yeast so that the seeded liquor has an initial concentration of yeast of between 0.25 and 60 g / l, preferably between 1 and 50 g / l.

The fermentation conditions obviously depend, to a large extent, on the yeast used and on the characteristics of the strong liquor. Fermentation is aerobic.

The fermentation can be carried out in fermenters of the type known for the fermentation of yeasts, that is to say in fermenters provided with a stirring and aeration device, and with a temperature regulation.

The fermentation temperature depends on the yeast used and is generally between 20 ° and 50 ° C. preferably between 30 and 45 ° C.

Agitation of the medium is carried out by any means, for example a pumping system circulating the liquor by an external loop, at a rate, for example, from 10 to 20 m ³ / h, or by a conventional agitation system such than a propeller driven by a motor (125-175 rpm). This agitation also allows better diffusion of the injected oxygen. Oxygen injection is carried out, for example, by injecting air through a ring pierced with holes located at the bottom of the fermenter, at a rate between 0.1 and 0.5 vvm (1 volume of oxygen / volume of liquor / minute), preferably 0.3 vvm.

Fermentation usually lasts from 1 h to 6 h, preferably 2 to 3 h.

When the fermentation is complete the fermentation product is purified. To do this, the fermented strong liquor is separated from the yeasts, for example, by centrifugation, which stops the fermentation. In a particular embodiment, the efficiency of the separation of the yeasts and the liquor is enhanced by treatment, after centrifugation, in a self-cleaning clarifier.

The purified strong liquor is then concentrated with a view to impregnating the base sheet.

The separated yeasts can be recycled as an inoculum for the following fermentations or can be used, for example, as animal feed.

The tobaccos which can be treated by such a reconstitution papermaking process are, in particular, all the "Virginia" type tobacco, "Bright" tobacco, coming from Brazil, China, Malawi, South Korea, Thailand, Philippines, Canada, India, Italy, Japan, USA, Zimbabwe, Zambia.

This flavoring treatment of strong liquor produces a reconstituted tobacco with characteristic and original organoleptic qualities.

The present invention also relates to the reconstituted flavored tobacco obtained by the process as well as the mixtures of this reconstituted tobacco with tobacco of different origins.

The reconstituted tobacco thus obtained was the subject of tasting tests by a group of specialists. Thanks to these tests, for cigarettes made up only of reconstituted flavored tobacco, we could see an improvement in certain "Virginie" notes, better "roundness" and better "balance".

Trials of introduction of this reconstituted tobacco flavored for 30% in a commercial Virginia mixture made it possible to note the presence of these notes, the certain improvement in the taste qualities with respect to cigarettes comprising untreated reconstituted tobacco and a reduction usual organoleptic characteristics of untreated reconstituted tobacco.

• . la figure 1 donne le schéma du procédé papetier de reconstitution du tabac classique, décrit plus haut;
• - la figure 2 donne une représentation schématique d'un mode de réalisation possible du procédé selon l'invention.

Other characteristics and advantages of the invention will appear on reading the examples below and in the appended figures:

• . FIG. 1 gives the diagram of the papermaking process for reconstituting conventional tobacco, described above;
• - Figure 2 gives a schematic representation of a possible embodiment of the method according to the invention.

After a stay in one of the digesters 10 or 11, tobacco debris in aqueous solution, the fibers are separated by passage through a press 12, the strong liquor which undergoes aromatization. The fibers leaving the press 12 are treated according to the conventional method to form a base sheet. The strong liquor passes through a screen 20 before being treated in one of the fermenters 21 or 22 which include a stirring device and an air injection device.

After fermentation, to separate the yeast, the strong liquor passes through a centrifuge 23, then through a self-settling clarifier 24, before its concentration in an evaporation device 17. The yeast is recovered at the outlet of the centrifuge and / or of the clarifier in a storage tank 25 for reuse for another fermentation or for recovery.

At the outlet of the concentration device 17, the strong flavored liquor is re-impregnated in the base sheet in the paper machine.

Example 1:

Fermentation of strong liquor on an industrial scale.

• L'extraction a été effectuée sur 500 kg de tabac dont 350 kg de Scraps Virginie et 150 kg de côtes Virginie. On a obtenu 3 600 litres de liqueur forte ayant un indice réfractométrique de 5% et contenant 13,6 g/I de sucres réducteurs.

This fermentation was carried out under the following conditions:

• The extraction was carried out on 500 kg of tobacco including 350 kg of Virginia Scraps and 150 kg of Virginia Ribs. 3600 liters of strong liquor were obtained, having a refractometric index of 5% and containing 13.6 g / l of reducing sugars.

The yeast used comes from a strain Saccharomyces cerevisiae, selected as previously described; it is cultivated in a synthetic culture medium of the following composition:

The reactor used is a 5,000 I tank fitted with a device for circulating cold or hot water to be able to regulate the temperature. Air is injected by a crown pierced with numerous holes and located at the bottom of the tank. Agitation is ensured by a pump recirculating the liquor by an external loop at the rate of 14 m ³ / h.

The temperature is regulated at 36 ° C.

The aeration obtained is 0.3 vvm.

The 3,600 liters of strong liquor are inoculated with 8.7 kg of yeast, an initial concentration of 2.42 g / l.

Fermentation was stopped after 2 hours, including 20 minutes of centrifugation. The refractometric index of the liquor was then 4% and the residual sugar concentration of 6.5 g / I.

During this fermentation 52.6% of the sugars were consumed.

Tasting result:

The panel of tasters was able to highlight, for the cigarettes corresponding to this product, an improvement in the "Virginia" notes such as "floral", "smoked wood" and "hay". In addition, the product had better "roundness" and better "balance".

Example 2:

Fermentation of strong liquor on an industrial scale.

• L'extraction est effectuée sur 500 kg de tabac dont:

• -150 kg côte Virginie
• - 250 kg scraps Virginie (Canada)
• - 100 kg de scraps Virginie (Zimbabwe).

This fermentation was carried out under the following conditions:

• The extraction is carried out on 500 kg of tobacco including:

• -150 kg Virginia coast
• - 250 kg Virginia scraps (Canada)
• - 100 kg of Virginia scraps (Zimbabwe).

4800 liters of strong liquor were obtained, having a refractometric index of 4% and containing 12.1 g / l of reducing sugars.

The yeast used is Saccharomyces cerevisiae, recycled after a previous fermentation.

The reactor used is practically the same as in Example 1.

The liquor was seeded with 7.87 kg of dry yeast, giving an initial concentration of 1.64 g / l.

Agitation is ensured by a driven propeller by a motor running at 150 rpm.

The temperature is regulated at 37 ° C.

The ventilation is fixed at 0.3 vvm, the air injection is carried out in the same way as in Example 1, but the oxygen transfer is improved by the addition of counterpales on the generators of the tank.

The purification is carried out by centrifugation, and the centrifuged strong liquor is then treated in a self-shedding clarifier (Westphalia ^@ ).

The culture is stopped by starting the centrifugation at the most opportune time, that is to say after 2 h 40 of culture; the purge ends 40 minutes later. At that time, 73.5% of the reducing sugars are consumed.

Tasting result:

The presence of "Virginia" notes and the reduction in the characteristics of a reconstituted tobacco have been confirmed for cigarettes made from processed reconstituted tobacco.

The 30% introduction tests in a commercial Virginia mixture made it possible to obtain results comparable to those of the previous example.

Claims (9)

1. A method for the preparation of aromatized reconstituted tobacco starting with tobacco particles, in which these particles are mixed with water to obtain, on the one hand, an aqueous solution (called "strong liquor") containing watersoluble products of the tobacco particles and, on the other hand, insoluble products, the strong liquor is separated from the insoluble products, the strong liquor is concentrated, sheets are prepared from said insoluble products and said concentrated strong liquor is incorporated into the sheets so as to obtain, after drying, reconstituted tobacco sheets, wherein, before concentrating, said strong liquor is seeded with yeast and the yeasts are removed after fermentation.

2. The method as claimed in claim 1, wherein the strong liquor has initially a refractometric value of between 1% and 15%, preferably between 4% and 12%.

3. The method as claimed in claim 1 or 2, wherein the seeded strong liquor has an initial yeast concentration of between 0.25 and 60 g/I, preferably between 1 and 50 g/I.

4. The method as claimed in claim 1, wherein the yeast strain is chosen from amongst the genera Kluyveromyces, Saccharomyces and Candida.

5. The method as claimed in claim 4, wherein the yeast strain is of the Saccharomyces cerevisiae type.

6. The method as claimed in claim 1, wherein the fermentation is aerobic.

7. The method as claimed in one of claims 1 to 6, wherein the yeasts are removed by centrifugation of the fermented strong liquor.

8. Aromatized reconstituted tobacco obtained by the method as claimed in one of claims 1 to 7.

9. Mixed tobaccos which contain aromatized reconstituted tobacco as claimed in claim 8 in addition to tobacco from different sources.

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