SE501394C2 - Procedures for the treatment of green tobacco and the resulting product - Google Patents

Abstract

The invention relates to the manufacture of a nicotine-containing crude tobacco material from green tobacco by means of a process in which the tobacco plant material is converted to a pulp which is divided into a solid, coarse fraction and a liquid fraction. Suspended or emulsified fine material is then separated from the liquid fraction, resulting in a leaf nutrient concentrate containing pigment. This concentrate is divided into several pigment fractions with the aid of different extraction processes and these fractions are suitably treated and then optionally returned to the first, solid coarse fraction to enhance the flavour and appearance of the products. Proteins present in the liquid fraction left over at separation of leaf nutrient concentrate are totally removed, whereafter the deproteinized liquid fraction is processed while retaining the nicotine, so as to obtain a concentrated liquid phase that contains nicotine, flavourants and colourants and is then returned to the solid, coarse fraction, optionally together with other additives, so as to obtain the desired crude tobacco material. The invention also relates to the crude tobacco material obtained, intended for smokable and smokeless nicotine-containing products which in use have considerably reduced mutagenicity according to the Ames test and a low TSNA content.

Description

Such modified tobacco product, i.e. deproteinized tobacco, is described in US-A-4 289 147. However, according to the process described therein, a nicotine-free product is obtained, which the vast majority of consumers should perceive as a disadvantage, as nicotine-free products never gained commercial success.

Accordingly, the present invention relates to the preparation of a tobacco raw material for smokable or smoke-free nicotine-containing products which exhibit altered composition but with tobacco taste and aroma. The invention also relates to the product thus obtained.

An object of the invention is to obtain a different and improved product which contains reduced amounts of such components which on combustion can form undesirable substances. Another object of the invention is that whole tobacco plants can be used, as this simplifies the process and improves the yield. A further object of the invention is that green, ie immature, tobacco can be used in order to shorten the cultivation time, to increase possible cultivation zones and in order to obtain several harvests during a season.

A further object of the invention is to separate by-products which can be used directly or processed into valuable products.

Furthermore, an object of the invention is the production of a tobacco raw material with reduced mutagenicity defined according to, for example, the Ames test and a low content of TSNA (tobacco-specific nitrosamines). Further objects and advantages of the invention will become apparent from the following description.

According to the invention, the above objects are achieved with a method for treating green tobacco comprising transferring the tobacco plant material to a mass which is divided into a solid coarse fraction and a liquid fraction. Suspended or emulsified fine material is separated from the liquid fraction, whereby a foliar nutrient concentrate containing pigments is obtained, which by means of various extraction processes is divided into several pigment fractions which, after suitable processing, are wholly or partly returned to the first solid coarse fraction. From the liquid fraction remaining after the separation of the leaf nutrient concentrate, the constituent proteins are removed in whole or in part, after which the deproteinized liquid fraction is processed while retaining the nicotine to obtain a concentrated liquid phase, so-called liquid phase. , containing nicotine, flavors and dyes. This concentrated liquid phase is then returned to the solid coarse fraction, optionally together with other additives, to obtain the desired tobacco raw material.

US-A-4 343 317 describes a process for treating whole green tobacco leaves by squeezing protoplasmic juice out of the leaves by means of pressure and artificial maturation of the press mass.

Suitable methods for artificial maturation are stated to be 1) thermal browning by drying at ambient temperature and subsequent heating to 190 ° C for 15 minutes; 2) photobleaching, possibly after pre-treatment with steam, alcohol, etc., and subsequent thermal browning; 3) exposure of pressed tobacco to SO 2 gas to remove green color and flavors; and 4) soaking pressed tobacco in acidic (pH 1.5-3.5) medium and incubating the soaked mass at elevated temperature, preferably about 50 ° C until green disappears. The press juice can be processed for removal of various components, eg proteins, and / or for the development of flavors, and is then returned to the artificially matured press mass.

According to this patent, it is advantageous that whole green tobacco leaves can be used in the process without any separation of the leaves. Since whole green tobacco leaves are used, only a limited squeezing of protoplasmic juice from the tobacco leaves is achieved and the final product of the present invention can thus not be obtained. Another disadvantage of this known method is difficulties in carrying out the processing steps.

The aforementioned U.S. Pat. No. 4,289,147 discloses a process for treating tobacco, including green tobacco, to obtain a tobacco raw material from which protein, nicotine and green pigment have been removed. According to this method, the tobacco is transferred to a mass which is divided into a liquid fraction and a solid coarse fiber fraction. The liquid fraction, from which fine particulate matter has first been removed and which contains water-soluble plant material, is treated to remove proteins and nicotine. Pigments are removed from the fine particulate material, which is divided into green and non-green pigments 10 15 20 25 30 35 40 501 394 A å 4 pigments. The coarse fiber fraction, which has been decolorized by extraction of green and non-green pigment, is then combined with the non-green pigment obtained in previous steps and the liquid fraction, from which nicotine and protein have been removed. Although both of these patents describe processes for treating green tobacco, the methods described therein have disadvantages and do not provide a satisfactory tobacco raw material.

The process according to US-A-4 343 317 is furthermore primarily intended for the treatment of whole tobacco leaves and the mentioned methods for artificial maturation do not give a high quality product. As far as is known, this patent has not yet been used commercially and is in all probability difficult to apply on a commercial scale for tobacco products. According to US-A-4,289,147 a substantially nicotine-free product is obtained. However, the demand for essentially nicotine-free tobacco products is virtually non-existent. In addition, the obtained tobacco raw material is not of high quality and the process is difficult to carry out on a commercial scale.

According to the present invention, on the other hand, with the process described for the treatment of green tobacco, a good quality tobacco raw material is obtained which, when smoked, has a markedly reduced mutagenicity, for example according to the Ames test. The process also gives a low TSNA content in the tobacco raw material. It is also well suited for commercial use.

The process according to the present invention is described in more detail in the following with reference to the accompanying drawing, in which Fig. 1 shows a flow chart for a suitable embodiment of the process according to the invention. The present invention thus relates to a process for treating tobacco plant material for obtaining tobacco raw material intended for smokable and smoke-free nicotine-containing products, which in use have significantly reduced mutagenicity and low TSNA content, wherein (a) green tobacco in the form of whole plants or parts thereof are decomposed into a mass; (b) the pulp is separated into a solid fraction (I) comprising coarse solid material and a liquid fraction (II) comprising water-soluble tobacco plant material and suspended or emulsified fine material; (c) the liquid fraction (II) is separated into a liquid fraction (III) and a fraction (IV) containing the fine material; and is 501 394 (d) from the liquid fraction (III), proteins in the form of at least one fraction (V) are separated, whereby a liquid fraction (VI) is obtained, which process further comprises the steps (e) of the liquid fraction (VI). ) is adjusted to the appropriate pH, after which, optionally after oxidation thereof, it is concentrated to a fraction (VII) containing nicotine, dyes and flavors; (f) fraction IV from step (c) is slurried in alcohol or other water-miscible solvent and the resulting extract is hydrolyzed, suitably with the addition of base, after which the solvent is partially evaporated and the residue is extracted with non-polar solvent, after which a fraction (VIII) containing yellow-orange pigment is separated from a basic fraction (IX) containing green pigment; (g) extracting the fraction (IX) with polar, water-immiscible solvent, after which an extraction solvent fraction (X) containing polar pigment is separated; (h) from the aqueous phase (XI) from step (g) precipitated modified green pigment (XII), which after suitable processing gives chlorophyll-derived dyes and flavors (XIII); and (i) the fraction (I) from step (b) is combined, optionally after heating and drying thereof, with fractions VII and VIII and optionally also with fraction X and / or fraction XIII to obtain the tobacco raw material for the smoke product or the smoke-free product. .

The flow chart shown in Fig. 1 illustrates the various process steps and the numbering of fractions obtained. In the process according to the invention, green tobacco is used as starting material. Whole tobacco plants or parts thereof, such as the leaves, can be used. Preferably whole plants are used, especially if the tobacco is harvested at an early stage of growth. ' This plant material decomposes in step (a) into a mass, possibly with the addition of water. The decomposition is carried out in a conventional manner, for example by crushing or grinding.

The decomposition releases the liquid phase containing water-soluble plant material from the coarse solid material.

The decomposition can be carried out in the presence of suitable additives, eg antioxidants, such as reducing agents, to prevent oxidation of the polyphenols contained.

The division in step (b) takes place in a conventional manner. Suitably the mass is pressed, whereby a pressing juice or vegetable juice (fraction (II)) is separated from the pressing cake (fraction (I)).

Fraction (I), which is retained for use in the final step of the process, is suitably dried for preservative purposes to avoid deterioration of quality, for example due to bacterial and / or mold growth during storage.

The vegetable juice (fraction (II)) containing water-soluble plant material and suspended or emulsified fine material can be divided directly according to step (c) into the liquid fraction (III) and the fraction (IV) containing the fine material. Fraction (IV) is commonly referred to as leaf nutrient concentrate (BNK).

According to a preferred embodiment of the invention, however, the vegetable juice (fraction (II)) is heated before step (c) to a temperature of at most 55 ° C and preferably 40-45 ° C. The heating achieves partial coagulation of fine green pigment material, whereby separation of this material together with other substances constituting BNK is facilitated in the subsequent separation step (c).

The separation in step (c) is carried out by conventional techniques, for example centrifugation or filtration. If the above-mentioned heat treatment is carried out, moderate centrifugal forces are generally sufficient to achieve the separation.

Proteins are then removed from the liquid fraction (III).

It is known that proteins give rise to impaired taste (Schmuck index) when burning, for example, a cigarette. Mutagenic substances can also be formed during the combustion of proteins. Accordingly, it is desirable that proteins be completely or at least partially separated from the tobacco raw material. This can take the form of one or more protein fractions. If the proteins are separated in the form of a fraction (V), this is conveniently done by heating the liquid fraction (III) to such a temperature that all; proteins coagulate, ie to at least 52 ° C and suitably to 75-85 ° C. The fraction (V) can then be separated, for example by centrifugation. Alternatively, the proteins may be precipitated by acidification, suitably to a pH of 4.5 or lower.

It is preferred that substantially all of the proteins be precipitated in a single step, and then separated. Methods for implementing this have been well known for a long time.

For the liquid fraction (VI) which thus does not contain proteins or has a reduced protein content, the pH value is then adjusted in step (e) to the appropriate value, after which certain components included in this fraction possibly oxidized. If the oxidation is carried out in an acidic environment, a suitable pH range is from 3 to 4, and a pH value of 3, which can be achieved by adding phosphoric acid, is particularly suitable. Alternatively, other acids may be used, such as citric acid, succinic acid and other organic acids.

The oxidation is carried out by adding oxidizing agent at room temperature or preferably at an elevated temperature of 30-100 ° C, preferably 70-90 ° C. A suitable oxidizing agent is H 2 O 2. Other oxidizing agents that can be used are organic peracids.- With the oxidation process, at least partial oxidation of aromatics to a quinoid-type structure is achieved. This corresponds to the oxidation that occurs during conventional maturation of tobacco by air drying.

After concentrating in a conventional manner, for example by evaporation, of the optionally oxidized fraction, a fraction (VII), usually called brown juice, is obtained, which contains nicotine, dyes and flavors. This brown juice is returned in the final step to fraction (I).

The foliar nutrient concentrate (BNK), ie fraction (IV), is processed according to the invention in steps (f) - (h) for the recovery of valuable products, which can be returned to fraction (I) and / or used in another way. Unlike prior art, the green pigment after processing also gives a valuable product (fraction (XIII)).

In step (f), the fraction (IV) is slurried in an alcohol, for example methanol, ethanol or isopropanol, or in another water-miscible solvent. This solubilizes the leaf pigments and BNK, which has been discolored, constitutes a suitable animal feed with a high protein and starch content. Since green pigment is insoluble in water, dissolved pigment is hydrolyzed, for example at ambient temperature and with the addition of a base, for example an alkali hydroxide, such as potassium hydroxide. As alcohol, ethanol is suitably used, for example in an amount which gives a solution containing 60-85% by volume of ethanol. After partial evaporation of the solvent, eg to a 20% ethanol solution, the residue is extracted with a non-polar solvent, eg heptane. The separated fraction (VIII) thus contains yellow-orange pigment dissolved in the non-polar solvent. The extraction preferably takes place at ambient temperature. the hydrolysis is also advantageously carried out at ambient temperature, although elevated temperature can be used, for example to accelerate the hydrolysis.

The aqueous solvent fraction (IX) containing dissolved green pigment is then extracted with a polar, water-immiscible solvent, to separate a polar pigment (fraction (X)). A suitable solvent is ethyl acetate.

By the terms "water-immiscible" and "immiscible" solvent is meant that the solvent is substantially immiscible with water. Solvents covered by this term may thus have a certain miscibility with water, namely up to about 10%.

The polar pigment is xanthophyll. It can be returned to fraction (I) or used for other purposes, for example as an additive for animal feed or as colorants for food.

From the remaining aqueous fraction (XII) containing green pigment, a modified green pigment is then precipitated with any suitable precipitating agent, such as iron compounds including iron (III) nitrate, iron (III) citrate, iron (III) acetate, iron (III) formate , iron (III) oxide and corresponding iron (II) compounds under acidic conditions. The precipitation can mean that the green color changes to another color, eg black if an iron compound is used for the precipitation. This modified "green pigment" is then further processed to give chlorophyll-derived dyes and flavors (fraction (XIII)). Such processing of the modified "green pigment" involves oxidation and esterification. First, the black precipitate is solubilized in acetic acid with the addition of H 2 O 2, after which the mixture is refluxed at 108-110 ° C for 30 minutes and then cooled.

To the same mixture is added propanol for esterification in the presence of a small amount of sulfuric acid. The resulting solution contains chlorophyll derivatives of a reddish brown color and is neutralized to pH 6-7 with a base such as potassium hydroxide.

The final step in the process according to the invention comprises that the fraction (I) is combined with the brown juice (fraction (VII)) and possibly also with other fractions from previous process steps. This can be achieved, for example, by spraying the brown juice and / or other liquid fractions over the fraction (I) while mixing it, for example by rotation.

Preferably, an elevated temperature of 80-100 ° C is used. Non-liquid fractions to be returned to fraction (I) are dissolved in a suitable solvent, for example an alcohol, such as ethanol, and then sprayed over fraction (I), as indicated above.

The following examples illustrate suitable embodiments of the invention. However, the invention is not limited to its embodiments.

Example 1 5500 kg of young green tobacco with less than 25% of the flowers knocked out are harvested as whole plants. The plants are chopped into pieces about 30 mm long, after which they, with the addition of 0.5 weight equivalents of water containing 1% by weight of sodium metabisulfite, are broken down in a mill. The slurry thus obtained is divided by pressing in a screw press into a solid (fraction I) and a liquid phase, ie vegetable juice, (fraction II).

The solid phase (fraction I) is washed with water, diluted with 3-4 times as much water with stirring and pressed again in a screw press, giving a solid phase and a liquid phase, which is discarded. The solid phase is fluffed and possibly decomposed in a refiner before being dried by heat in a conventional manner to 90% ts (dry matter).

The solid thus obtained, of processed fraction (I), can be used as is. In this example, however, it was divided into two fractions, namely a fibrous, long fraction, called Fiber A in the table below, (120 kg) and a small tobacco fraction (110 kg). The first of these fractions was used as a reference material in smoke evaluations. The results from these are summarized in Table I.

The vegetable juice (fraction II) from the first pressing is adjusted with phosphoric acid to a pH of 5.15 and heated to 45 ° C. This temperature is maintained for about 10 minutes, after which the fine precipitated material, the leaf nutrient concentrate (fraction IV) (240 kg, 28% ts), is separated by decantation from the aqueous phase (III), also called yellow juice.

To the aqueous phase thus obtained, CO 2 (g) is added to saturation whereby the F1 proteins precipitate or crystallize out and are separated from the juice by centrifugation or filtration. The remaining soluble proteins are coagulated by adjusting the pH of the juice to 3.5 with phosphoric acid (the juice is allowed to stand for about 1 hour) and then the F2 proteins are separated from the liquid phase (fraction VI). ie the brown juice, by centrifugation or filtration.

The pH of the brown juice is adjusted to 3 with phosphoric acid and 30% hydrogen peroxide is added (200: 1, based on volume), after which the brown juice is heated at 80 ° C overnight. The brown juice is concentrated to 50% ts (fraction VII) and can then be stored for later use. This concentrated brown juice (fraction VII) is hereinafter referred to as BS A.

After dilution with water, the concentrated brown juice BS A is added to the above-obtained long, fibrous material, Fiber A, in a ratio of 4 kg teaspoon of brown juice to 10 kg teaspoon of solid material, after which the obtained material is dried to 14-18% and filterless cigarettes are manufactured in a conventional cigarette machine. Cigarettes are also made from the fibrous, long material, Fiber A, without the addition of BS A.

The results of tests of these cigarettes, and as a comparison, a marketed conventional, filterless cigarette of the "American blend" type, are reported in Table I below.

Example 2. 2900 kg of green, flowering tobacco is harvested, chopped, crushed and pressed as indicated in Example 1. The solid (fraction I) is washed, pressed, fluffed, dried and then sieved in the same manner as in Example 1, giving 100 kg of the fibrous, long fraction, is denoted Fiber B, and 90 kg of a small tobacco fraction. The vegetable juice (fraction II) from the first pressing is adjusted with phosphoric acid to a pH value of 3.5 and then heated to 75 ° C, which temperature is maintained for about 15 minutes, after which the fine precipitated material (175 kg, 28% ts) (fraction (IV) + (V)) is separated by a decantation from the aqueous phase (brown juice) (fraction (VI)).

The brown juice (fraction (VI)) is adjusted to a pH of 3 with phosphoric acid and 30% hydrogen peroxide is added (200: 1, based on volume), after which the brown juice is heated at 80 ° C overnight. The brown juice is concentrated to 80% ts and can then be stored for later use. This concentrated brown juice (fraction (VII)) is hereinafter referred to as BS B. After dilution with water, the concentrated brown juice, BS B, is added to the long fibrous material, Fiber A, from Example 1 in a ratio of 10 μl 501 394 of 4 kg teaspoon of brown juice to 10 kg teaspoon of solid material, after which the resulting material is dried to 14-18% teaspoon and filterless cigarettes are manufactured in a conventional cigarette machine. Cigarettes are also made from the fibrous, long material obtained above from the full-grown plants (Fiber B).

The results of tests of these cigarettes are also summarized in Table I.

Table I AMES TEST OF SMOKE CONDENSATION FROM MACHINE-SMOKED CIGARETTES Cigarette Tar (mg / ct) Ames (TA98 + S9, rev / mg tar) Fiber A 18.2 553 Fiber B 16.6 422 Fiber A + Bs A 18.7 524 Fiber A + Bs B 19.4 629 * "American-blend" - 22.0 1698 * TYPE The table clearly shows that the products of the present invention have a lower tar content and a considerably lower mutagenicity when used than a conventional type cigarette ("American blend ").

Claims (11)

10 15 20 25 30 35 40 501 394 ß Patent claim A process for the treatment of tobacco plant material for obtaining tobacco raw material intended for smokable and smoke-free nicotine-containing products, which in use has significantly reduced mutagenicity according to the Ames test and low content of tobacco-specific nitrosamines (TSNA), wherein - (a) green tobacco in the form of whole plants or parts thereof are decomposed into a mass; (b) the pulp is separated into a solid fraction (I) comprising coarse solid material and a liquid fraction (II) comprising water-soluble tobacco plant material and suspended or emulsified fine material; (c) the liquid fraction (II) is separated into a liquid fraction (III) and a fraction (IV) containing the fine material; and (d) proteins are separated from the liquid fraction (III) in the form of at least one fraction (V), a liquid fraction (VI) being obtained, characterized in that (e) the liquid fraction (VI) is adjusted to a suitable pH value, after which it, optionally after oxidation thereof, is concentrated to a fraction (VII) containing nicotine, dyes and flavors; (f) fraction IV from step (c) is slurried in alcohol or other water-miscible solvent and the resulting extract is hydrolyzed, preferably using a base, after which the solvent is partially evaporated and the resulting concentrate is extracted with a non-polar solvent, after which a fraction (VIII) containing yellow-orange pigment is separated from a basic fraction (IX) containing green pigment; (g) the fraction (IX) is extracted with polar, immiscible solvent, after which an extraction solvent fraction (X) containing polar pigment is separated; (h) from the aqueous phase (XI) from step (g) precipitated modified green pigment (XII), which after appropriate processing gives chlorophyll-derived dyes and flavors (XIII); and (i) the fraction (I) from step (b) is combined, optionally after heating and drying thereof, with fractions VII and VIII and optionally also with fraction X and / or fraction XIII to obtain the tobacco raw material for the smoke product or the smoke-free product. 10 15 20 25 30 35 40 b 501 394 Process according to Claim 1, characterized in that before step (c) the liquid fraction (II) is heated to a temperature of at most 47 ° C. 3. A process according to claim 1 or 2, characterized in that the oxidation in step (e) is carried out at a temperature of 20-100 ° C using H53 as oxidizing agent. 4. A process according to claim 1, 2 or 3, characterized in that the alcohol in step (f) is ethanol. Process according to any one of the preceding claims, characterized in that in step (f) the base is potassium hydroxide. Process according to any one of the preceding claims, characterized in that the non-polar solvent in step (f) is heptane. Process according to any one of the preceding claims, characterized in that in step (g) the extraction is carried out with ethyl acetate or propyl acetate or ethers, such as diethyl, dipropyl or diisopropyl ethers. Process according to one of the preceding claims, characterized in that modified green pigment is precipitated with iron in step (h) at a pH value of 6 or lower, the iron being in the form of iron (III) - or iron (II) compounds. Process according to any one of the preceding claims, characterized in that the precipitate of iron / green pigment is oxidized in acetic acid in step (h) at a temperature of 108-110%: using Hgg as oxidizing agent. Process according to any one of the preceding claims, characterized in that oxidized iron / green pigment is esterified in propanol in step (h) at a temperature of 80-110% L 11. A product, characterized in that it is a tobacco raw material for smokable and smoke-free, nicotine-containing products, which in use has significantly reduced mutagenicity according to the Ames test and low content of tobacco-specific nitrosamines (TSNA), and is prepared by the process according to requirement 1.