Claims:1) A non-aqueous solvent system to reduce nicotine in tobacco comprising:
(i) at least one non-polar solvent;
(ii) at least one polar solvent in combination with at least one pH modifying agent (alkaline-polar solvent solution);
wherein the ratio of non-polar solvent to alkaline-polar solvent solution is 9:1; and wherein the pH modifying agent has a concentration from 0.001N to 1N.

2) The solvent system as claimed in claim 1, wherein said non-polar organic solvent petroleum ether or n-hexane, preferably n-hexane.

3) The solvent system as claimed in claim 1, wherein said polar solvent is selected from ethanol, isopropyl alcohol (IPA) or mixtures thereof, preferably ethanol.

4) The solvent system as claimed in claim 1, wherein said pH modifying agent is hydroxides of alkali metals such as lithium, sodium, potassium and caesium/cesium, preferably hydroxides of sodium and potassium.

5) The solvent system as claimed in claim 1, wherein the concentration of the pH modifying agent is from 0.001N to 1N.

6) A non-aqueous solvent system to reduce nicotine content in tobacco comprising:
(i) n-hexane;
(ii) ethanolic solvent containing ethanol and potassium hydroxide; and
wherein the ratio of n-hexane to ethanolic solvent is 9:1; and
wherein potassium hydroxide has a concentration from 0.001N to 1N.
7) The solvent system as claimed in claim 5, wherein concentration of potassium hydroxide in the range of 0.25 N to 0.5 N.

8) The solvent system as claimed in claim 5, wherein the ethanolic solvent comprising 0.5 N potassium hydroxide reduces the nicotine content in the range of 30 to60%.

9) The solvent system as claimed in claim 1, wherein the ethanolic solvent comprising 0.5 N potassium hydroxide reduces B(a)P by at least 30%.

10) The solvent system as claimed in claim 1, wherein the ethanolic solvent comprising 0.5 N potassium hydroxide reduces TSNA by at least 40%.

11) A process for treating tobacco for selective reduction of nicotine content, wherein the process comprises the steps of:
(i) soaking tobacco in a non-aqueous solvent system for about 24 hours;
(ii) removing the solvent of step (i);
(iii) soaking of tobacco of step (ii) in a freshly prepared non-aqueous solvent system for about 3 to 6 hours;
wherein the non-aqueous solvent system comprises at least one non-polar solvent; and at least one polar solvent in combination with at least one pH modifying agent (alkaline-polar solvent solution) such that ratio of non-polar to alkaline-polar solvent solution is 9:1; and
wherein the concentration of pH modifying agent in solvent system of step (i) and (iii) is 0.5 N and 0.25N respectively.
12) The process as claimed in claim 11, wherein said non-polar organic solvent petroleum ether or n-hexane, preferably n-hexane.

13) The process as claimed in claim 11, wherein said polar solvent is selected from ethanol, isopropyl alcohol (IPA) or mixtures thereof, preferably ethanol.

14) The process as claimed in claim 11, wherein said pH modifying agent is hydroxides of alkali metals such as lithium, sodium, potassium and caesium/cesium, preferably hydroxides of sodium and potassium.

15) The process as claimed in claim 11, wherein the concentration of the pH modifying agent is from 0.001N to 1N.

16) A process for treating tobacco for selective reduction of nicotine content, wherein the process comprises the steps of:
(i) soaking tobacco in a non-aqueous solvent system for about 24 hours;
(ii) removing the solvent of step (i);
(iii) soaking of tobacco of step (ii) in a freshly prepared non-aqueous solvent system for about 3 to 6 hours; and
wherein the non-aqueous solvent system comprises n-hexane; and ethanolic solvent containing ethanol and potassium hydroxide such that the ratio of n-hexane to ethanolic solvent is 9:1; and
wherein the concentration of potassium hydroxide in solvent system of step (i) and (iii) is 0.5 N and 0.25N respectively.

17) A combustible or smokeable product comprising treated tobacco as obtained by process claimed in the preceding claims.

18) The combustible or smokeable products as claimed in claim 17 is cigarette, cigar, cheroot, heat-not-burn formats and the like.
, Description:TECHNICAL FIELD
The present invention relates to a tobacco treatment method utilizing a solvent system to reduce the nicotine content along with undesirable compounds like tobacco specific nitrosamines (TSNAs) and polynuclear aromatic hydrocarbons (PAHs).
BACKGROUND OF INVENTION AND PRIOR ART
Various parts of tobacco plant such as tobacco leaves, cut tobacco, midribs, stems and roots, which are consumed, contain different chemical constituents along with major component nicotine. These constituents are responsible for texture, flavour and other organoleptic properties of tobacco and its products. However, compounds like tobacco specific nitrosamine (TSNAs), polynuclear aromatic hydrocarbons (PAHs) such as benzo (a) pyrene (BaP), carbonyls, phenol, and catechol are undesirable and toxic components of tobacco.

Generally, a cigarette is made up of 750 mg of tobacco which constitutes TNA (Total Nicotine as Alkaloids) content about 1.4-1.5% of total weight and TSNA (tobacco specific nitrosamines) in range of 0.4-8 µg/g. Further the content analysis of main stream smoke of such cigarette illustrates nicotine-1 mg, TSNA- 150-400 ppb and bezopyrine (B(a)P) - 0.12-0.18 µg/g, the contents of TNA and TSNA may vary in different varieties of tobacco.

According to recent guidelines of WHO-Study-Group on “Tobacco Product Regulation (TobReg)”, a reduced nicotine level as low as 0.1 mg per gm of tobacco is recommended in consumable tobacco and product thereof. Therefore, it is strongly recommended to treat the tobacco to reduce nicotine or TNA along with undesired constituents yet maintain its structural integrity and have minimal impact on sensorial properties such as taste, flavor, irritation, mouthfulness, draw effort which is known in the art.

US Patent no US 2822306 describes a tobacco treatment method for nicotine extraction employing solvent extraction technique by Soxhlet method. The leaching method of extracting nicotine by neutralizing nicotine acid salts of natural tobacco in presence of large volumes of water containing basic salts. Such leaching methods lead to removal of considerable amount of desired soluble salts of tobacco other than nicotine, responsible for its taste and flavour. Further, these soluble salts are recovered upon concentrating the extract, which are added back in tobacco to preserve its taste characteristics.

US Patent no US1949012A describes a method of preparing tobacco free from nicotine. The method involves tobacco treatment with an organic solvent for substantial extraction of nicotine. Further, removing the nicotine from the extract by treating it with an acid aqueous washing liquid, steam distilling the washing liquid, shaking the distillate with the original extraction solvent, and combining any aromatic substances thus obtained and the other nicotine free extracts with the treated tobacco.

US Patent no US4068671A describes a tobacco treatment method for selective removal of nicotine without substantially removing soluble-constituents other than nicotine. The method involves the steps of: forming an aqueous dispersion of tobacco (pH around 8.5) and rapid air convection drying of said dispersion at an elevated temperature and air flow rates, further rewetting the dried tobacco product with water, and repeating the dispersion and rapid drying steps to further reduce the nicotine content.

US Patent no US 4289147A describes a tobacco treatment method and production of a tobacco product having reduced protein, nicotine and tar content but desirable flavor constituents. The said treatment method involves pulverization of leaves and/or stalks of tobacco to liberate a liquid portion which is treated to remove water-soluble proteins and nicotine. The solid left behind, is further treated to remove water insoluble protein, nicotine and green pigments. The residues obtained after separation of soluble and insoluble contents of the pulverized leaves and/or stalks are recombined to yield a processed tobacco which is suitable for use in cigarettes as a tobacco filler or other products.

Indian Patent Application no 1037/KOL/2014, published on August 26, 2016 discloses a tobacco treatment method utilizing a solvent system for selective reduction of tobacco specific nitrosamines and hydrocarbons like benzopyrine. The method involves washing the tobacco with organic solvent mixture repeatedly to attain a particular reduced concentration of nitrosamines and hydrocarbons in the treated tobacco and product thereof.

As apparent, there is need for a simple process and a solvent system for reducing nicotine from tobacco to produce a tobacco of reduced nicotine content without degrading the structural integrity or other organoleptic properties of tobacco, or without necessitating costly and time-consuming extractive procedures which in turn necessitate reconstitution of the tobacco by returning the tobacco solubles other than nicotine to the treated (extracted) tobacco.

Accordingly, the present invention provides a simple, economical and highly efficient process and solvent system for reducing nicotine from tobacco yet maintaining and retaining the structural integrity and other organoleptic properties of tobacco.

OBJECTIVES OF THE INVENTION
The primary objective of the present invention is to overcome the conventional problems in the prior art.

One of the objects of the invention is to provide a solvent system for reducing the nicotine content in tobacco along with nitrosamines and benzopyrine comprising at least one polar solvent, one non-polar solvent and a pH modifying agent.

It is another object of the invention to provide a tobacco treatment method employing a solvent system comprising at least one polar solvent, one non-polar solvent and a pH modifying agent for substantial reduction of nicotine along with nitrosamines and benzopyrine.

It is yet another object of the present invention to provide a tobacco treatment method employing a solvent system to effectively reduce nicotine, TSNA and hydrocarbons without altering texture, flavor and structural integrity of tobacco.

It is a further object of the invention to provide a convenient and cost effective method of tobacco treatment employing simple washing of tobacco with a solvent system, without utilizing high throughput machines or technical complexities.

One more object of the present invention is to provide a combustible or smokeable products like cigarette, cigar and cheroot utilizing the treated tobacco with reduced nicotine content.

SUMMARY OF INVENTION:
In one aspect, the present invention provides a non-aqueous solvent system to reduce nicotine in tobacco comprising:
(i) at least one non-polar solvent;
(ii) at least one polar solvent in combination with at least one pH modifying agent (alkaline-polar solvent solution);
wherein the ratio of non-polar solvent to alkaline-polar solvent solution is 9:1; and wherein the pH modifying agent has a concentration from 0.001N to 1N.
In another aspect the present invention provides a non-aqueous solvent system to reduce nicotine content in tobacco comprising:
(i) n-hexane;
(ii) ethanolic solvent containing ethanol and potassium hydroxide;
wherein the ratio of n-hexane to ethanolic solvent is 9:1; and
wherein the potassium hydroxide has a concentration from 0.001N to 1N.
In yet another aspect the present invention provides a process for treating tobacco for selective reduction of nicotine content, wherein the process comprises the steps of:
(i) soaking tobacco in a non-aqueous solvent system for about 24 hours;
(ii) removing the solvent of step (i);
(iii) soaking of tobacco of step (ii) in a freshly prepared non-aqueous solvent system for about 3 to 6 hours; and
wherein the non-aqueous solvent system comprises at least one non-polar solvent; at least one polar solvent in combination with at least one pH modifying agent (alkaline-polar solvent solution) such that ratio of non-polar to alkaline-polar solvent solution is 9:1.
In a further aspect the present invention provides a process for treating tobacco for selective reduction of nicotine content, wherein the process comprises the steps of:
(i) soaking tobacco in a non-aqueous solvent system for about 24 hours;
(ii) removing the solvent of step (i);
(iii) soaking of tobacco of step (ii) in a freshly prepared non-aqueous solvent system for about 3 to 6 hours; and
wherein the non-aqueous solvent system comprises n-hexane; and ethanolic solvent containing ethanol and potassium hydroxide such that the ratio of n-hexane to ethanolic solvent is 9:1; and
wherein the concentration of KOH in solvent system of step (i) and (iii) is 0.5 N and 0.25N respectively.
DETAILED DESCRIPTION OF THE INVENTION
The following description is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein, can be made without departing from the scope of the invention.

Apparently, the described embodiments are merely a part, rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art, based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment.

The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention.

These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The term “TSNAs” used in the specification refers to “tobacco specific nitrosamines” present in various parts of tobacco plant (e.g. leaves, stem, and petiole) as well as in smoke produced by different smokeable tobacco-articles. TSNAs include Nicotine-derived nitrosamine ketone (NNK) and N-nitrosonornicotine (NNN).

The term “PAHs” used in the specification refers to polynuclear aromatic hydrocarbons like bezopyrine, present in various parts of tobacco plant (e.g. leaves, stem, and petiole) and smoke produced by product thereof.

The term “TNA” used in the specification refers to “total nicotine as alkaloid”, present in crude tobacco and product thereof.

It is known that consumption of tobacco and its products are injurious to health, but still they are in the market due to consumer demands. Therefore, continuous efforts are being made to minimize the health risks and nicotine dependence of tobacco consumers. Different tobacco treatment methods have been developed to reduce the undesirable compounds like PAHs, TSNAs, carbazole, phenol, and catechol that are the cause of morbidity and mortality to smokers. They are formed by reactions involving free nitrate during processing and storage of tobacco and by combustion of tobacco containing nicotine and nor-nicotine in a nitrate rich environment. Since the nitrate level of tobacco is important for nitrosamine formation in cigarette smoke, a significant reduction of nitrosamines in smoke negatively affects the smoke ability or the taste of the tobacco. Further, most of the known methods of reducing nicotine content from tobacco include extractive procedures which in turn necessitate time and cost intensive steps of reconstitution of the extracted tobacco by returning the flavour imparting constituents like, volatile oils, pigments and taste enhancers to it. Several approaches to reduce the amount of nicotine along with said undesirable compounds require use of high throughput machines thus making them expensive and complicated.

Unexpectedly, the present inventors have found a simple yet effective non- aqueous solvent system comprising a polar solvent, a non-polar organic solvent and a pH modifying agent selectively and effectively extract nicotine along with reducing TSNA and B(a)P without altering the structural integrity and organoleptic properties of treated tobacco. Further the process does not have any adverse effect on smokability and taste of the tobacco.

Suitable polar solvent is selected from a group of solvents like ethanol, methanol, propanol, isopropyl alcohol, and dichloromethane.

Suitable non-polar organic solvent is selected from a group of solvents like n-hexane, petroleum, and ether.

Suitable pH modifying agent is selected from organic or inorganic bases. Preferably carbonates and hydroxides of alkali and alkaline earth metals are used. More preferably, hydroxides of alkali metals such as lithium, sodium, potassium and caesium/cesium. Most preferably, hydroxides of sodium and potassium are preferred.

According to the present invention, an alkaline-polar solvent solution is prepared by dissolving specific amounts of pH modifying agent in the polar solvent. The alkaline-polar solvent solution maintains the desired pH of the solvent system. Preferably the alkaline-polar solvent solution is a solution of potassium hydroxide with ethanol, also referred to as the ethanolic solvent.

The ratio of the non-polar solvent to alkaline-polar solvent solution is 9:1.

In the present invention the concentration of potassium hydroxide in the ethanolic solvent may vary from 0.001N to 1N, preferably from 0.1N to 0.5N, more preferably from 0.25N to 0.5N.
The present invention also provides a tobacco treatment method employing the solvent system of the present invention wherein the method comprises the steps of:
(i) soaking tobacco in said solvent system for about 24 hours;
(ii) removing the solvent of step (i);
(iii) soaking of tobacco of step (ii) in a freshly prepared solvent system for about 3 to 6 hours; and
wherein the concentration of alkali in the alkaline-polar solvent solution in solvent system of step (i) and (iii) is 0.5 N and 0.25N respectively.
In a preferred embodiment, the process for reducing nicotine in tobacco comprises the steps of:
(i) soaking tobacco in a non-aqueous solvent system comprising n-hexane; ethanolic solvent containing ethanol and potassium hydroxide for about 24 hours;
(ii) removing the solvent of step (i);
(iii) soaking of tobacco of step (ii) in a freshly prepared non-aqueous solvent system for about 3 to 6 hours;
wherein the non-aqueous solvent system comprises n-hexane; and ethanolic solvent containing ethanol and potassium hydroxide such that the ratio of n-hexane to ethanolic solvent is 9:1; and
wherein the concentration of KOH in solvent system of step (i) and (iii) is 0.5 N and 0.25N respectively.
The present solvent system and the process can be employed with whole cured tobacco leaf, cut or chopped tobacco, tobacco filler, reconstituted tobacco, tobacco stems and the like. As used herein, references to tobacco and tobacco materials include all such forms of tobacco. Further it is to be understood that the tobacco treated in accordance with the invention reduces nicotine, TSNAs), polynuclear aromatic hydrocarbons (PAHs) such as benzo(a)pyrene B(a)P in any tobacco product which is consumed by combustion and that references to smoking tobacco products include cigars, cigarettes, cigarillos, pipe tobacco and the like.
Further, the treated tobacco has been analysed for percentage reduction of nicotine and other undesirable compounds with respect to control (untreated tobacco).
Example 1
Preparation of KOH solution in IPA/Ethanol
Equivalent weight of KOH is 56.11. Hence 56.11gm of KOH will be dissolved in one litre of Ethanol/IPA to prepare 1N KOH. Similarly, for different concentrations, the following table shows the amount of KOH requirements.

Sl No

Normality (N)
Amount of KOH required to prepare mentioned strength solution in one litre of IPA/Ethanol
1 1.0 56.11gm
2 0.5 28.05gm
3 0.25 14.02gm
4 0.1 5.61gm
5 0.01 0.561gm
6 0.001 0.0561gm

Hexane was mixed with above made KOH solution in IPA/Ethanol at a ratio of 9:1 (v/v).
Final volume required to completely soak the tobacco depends on the quantity of tobacco to be washed, which can ascertained by a person of average skill in the art, without undue experimentation and in reliance upon personal knowledge and the disclosure of this application.
Example 2
Process for treating tobacco to reduce to reduce nicotine along with tobacco specific nitrosamines (TSNAs), polynuclear aromatic hydrocarbons (PAHs) such as benzo(a)pyrene B(a)P
A known amount of cut tobacco was soaked in a solvent mixture of Hexane : Alkaline Ethanol (9:1) solvent system for about 24hrs.. Alkaline ethanol was formed by dissolving specific amount of potassium hydroxide in ethanol. Post 24 h soaking, solvent was removed and the residual tobacco was further treated with the said solvent system for about 6 hrs. This was followed by solvent removal and drying the tobacco at room temperature. The concentration of potassium hydroxide in ethanol was varied from 1N to 0.001N. Tobacco post washing was analyzed along with control (unwashed) tobacco for constituent reduction as shown in table 1 below.

Table 1. Effect of Various Concentration of KOH in Solvent System.
Solvent system
% Reduction of constituents w.r.t control
NNN NNK B(a)P Nicotine
Hexane : Ethanol (9:1) containing 1 N KOH 65 71 68 84
Hexane : Ethanol (9:1) containing 0.5 N KOH 78 54 70 82
Hexane : Ethanol (9:1) containing 0.1 N KOH 56 71 70 28
Hexane : Ethanol (9:1) containing 0.01 N KOH 56 71 73 13
Hexane : Ethanol (9:1) containing 0.001 N KOH 51 57 75 11

Referring to table 1, it has been noted that, 1N KOH in solvent system leads to substantial reduction of nicotine (84%) along with nitrosamines (NNN (65%), NNK (71%) and benzopyrine (68%) with respect to control. However, this reduction in said contents also had an effect on the texture and physical characteristics.

Example 3
Process for treating tobacco to reduce to reduce nicotine along with tobacco specific nitrosamines (TSNAs), polynuclear aromatic hydrocarbons (PAHs) such as benzo(a)pyrene B(a)P
Similar to example 1, a process for treating tobacco employing the solvent system comprising varying concentration of KOH in the first and second washing of tobacco. The results obtained have been recorded in table 2.

Tables 2(a) and 2(b) Solvent systems comprising various concentrations of KOH

Solvent system % Reduction of constituents
NNN NNK B(a)P Nicotine
Hexane : Ethanol (9:1) - 0.5 N KOH only for 1st washing 57 62 61 50
Hexane : Ethanol (9:1) - 0.5 N KOH for 1st and 2nd washings 79 78 34 80
Hexane : Ethanol (9:1) - 0.25 N KOH for 1st and 2nd washings 60 64 26 56
Experiment set Solvent system % Reduction in Nicotine Content
Tobacco set 1 Hexane : IPA (9:1) - 0.5 N KOH for 1st and 2nd washing 66%
Hexane : IPA (9:1) - 0.5 N KOH for 1st and 0.25 N KOH for 2nd washing 60%
Hexane : IPA (9:1) - 0.25 N KOH for 1st and 2nd washing 48%
Tobacco set 2 Hexane : IPA (9:1) - 0.5 N KOH for 1st and 2nd washing 58%
Hexane : IPA (9:1) - 0.5 N KOH for 1st and 0.25 N KOH for 2nd washing 58%
Hexane : IPA (9:1) - 0.25 N KOH for 1st and 2nd washing 36%

Referring to table 2, it has been noted that upon choosing 0.5 N KOH for first and second washing, 80% reduction of nicotine can be achieved but it leads to sensorial and loss of integrity. However 0.25 N KOH, used for first and second washing gives 56% reduction of nicotine content without any substantial impact on the physical attributes of treated tobacco.

Example 4
Solvent systems comprising various concentrations of KOH
Two sets to experiments have been performed on tobacco samples using different combinations of solvent system comprising KOH ranging from 0.25N-0.5N in first and second washing of tobacco. The results obtained have been recorded in table 3.
Table 3
Experiment set Solvent system % reduction
NNN NNK B(a)P Nicotine
Set 1 Hexane: IPA (9:1)/0.5N KOH for 1st washing and 0.25N KOH for 2nd washing 61 60 51 34
Set 2 Hexane: IPA( 9:1)/0.5N KOH for 1st washing and 0.25N KOH for 2nd washing 56 58 60 43

Referring to table 3, it has been noted that 0.5N KOH used alone for first and second washing leads to 66% reduction of nicotine with structural damage to tobacco and loss of sensory properties. However upon using 0.25N KOH for first and second washing, only 48% reduction of nicotine is obtained. Results obtained in both the sets of the experiment reveal that washing with 0.5 N KOH followed by 0.25 N KOH solution leads to maximum extraction of nicotine along with TSNA, B(a)P, NNN, NNK reduction maintaining physical attributes and organoleptic properties of treated tobacco and product thereof.
Results obtained in both the sets of the experiment reveal that washing with 0.5 N KOH followed by 0.25 N KOH solution provided the maximum extraction of nicotine along with NNN and NNK while maintaining physical attributes and organoleptic properties of treated tobacco and products thereof.
Example 5
Analysis of nicotine content in main stream smoke
The treated tobacco of Set 1 and Set 2 were taken through standard mount devices (SMD) following standard protocols (familiar to those skilled in the art) and made into cigarettes. The cigarettes prepared have been analysed for nicotine content in main stream smoke with respect to control, following ISO guidelines. The results obtained have been recorded in Table 4.
Table 4. Percent Nicotine Reduction in Cigarette Smoke
Sample Set of Treated Tobacco % of Nicotine Reduction
in Smoke w.r.t Control
Set 1 42
Set 2 42

Referring to table 4, it can be deduced that upon utilizing the treated tobacco, obtained by washing with solvent system of present invention, a 42% reduction in nicotine content of cigarette smoke can be achieved, which is a very significant reduction.