WO2024149849A1

WO2024149849A1 - Process for producing a reconstituted rooibos sheet comprising stabilized nicotine

Info

Publication number: WO2024149849A1
Application number: PCT/EP2024/050606
Authority: WO
Inventors: Nathalie DUROT; Diane Raverdy-Lambert; Chistophe RIGOULAY
Original assignee: Swm Holdco Luxembourg
Current assignee: Swm Holdco Luxembourg
Priority date: 2023-01-11
Filing date: 2024-01-11
Publication date: 2024-07-18
Anticipated expiration: 2025-07-11
Also published as: EP4648624A1; EP4648625A1; KR20250135825A; WO2024149846A1

Abstract

The present invention relates to a process for producing a reconstituted rooibos sheet comprising nicotine stabilized by an acid.

Description

Title: PROCESS FOR PRODUCING A RECONSTITUTED ROOIBOS SHEET COMPRISING STABILIZED NICOTINE

Technical Field

[0001] The present disclosure belongs to the field of devices for heating tobacco without burning it and has as its subject a reconstituted rooibos sheet comprising stabilized nicotine.

Backg ound Art

[0002] A large number of devices for heating tobacco without burning it have been developed in order to avoid the formation of harmful constituents during tobacco combustion. By way of example, mention may be made of the applications published under numbers WO 2016/026810 and WO 2016/207407 which describe such devices. Tobacco sticks are placed into these devices, the tobacco is then heated by the device at a temperature below the combustion temperature without being burnt, which leads to the formation of an aerosol when the user sucks in air through the device. The generated aerosol replaces the cigarette smoke and has advantageous organoleptic properties when it is inhaled by the user. This allows the user to inhale nicotine and the tobacco aromas while at the same time very significantly reducing said user’s exposure to harmful constituents.

[0003] In order for the user to adopt these heating devices, it is important with said devices to have an experience as close as possible to the one obtained with a conventional cigarette, that is to say, for each puff, similar level of nicotine.

[0004] Natural tobacco leaves may not be suitable for such heating devices since they do not make it possible for the user to obtain a satisfactory experience.

[0005] Reconstituted tobacco is more suitable for these heating devices, since it makes it possible to easily apply high level of aerosol-generating agent and generate a significant amount of aerosol providing enough nicotine.

[0006] Tobacco aromas may be unpleasant, thereby reducing the number of potential users of the heating devices. Therefore, it may be advantageous to offer to the user of these heating devices neutral aroma.

Technical problem

[0007] There is therefore a need for a reconstituted plant sheet which have an appealing color and which generates an aerosol having a satisfactory amount of nicotine, a neutral aroma i.e. an aerosol which is satisfactory to the user.

[0008] It is thus to the credit of the inventors to have found that it is possible to meet this need by means of a reconstituted rooibos sheet comprising a salt of nicotine and having a specific range of pH. Summary

[0009] It is proposed a reconstituted rooibos sheet comprising:

- a fibrous support comprising rooibos fibers,

- an aerosol-generating agent, and

- a rooibos extract, characterized in that it further comprises nicotine and an organic acid, or a salt of nicotine, and it has a pH from 4.9 to 7.0, in particular from 5.5 to 6.5.

[0010] Advantageously, the reconstituted rooibos sheet of the present invention generates an aerosol providing nicotine in a satisfactory manner and having no unpleasant harshness and acidic taste, i.e. an aerosol which is satisfactory to the user.

[0011] Without wishing to be bound to any theory, the inventors are of the opinion that these results may be explained by:

- the monoprotonated form of nicotine being the main form of nicotine in the reconstituted rooibos sheet of the present invention. The monoprotonated form results from the formation of a salt of nicotine by a reaction between the nicotine and the organic acid. The monoprotonated form is efficiently released in the aerosol during the use of the reconstituted rooibos sheet of the present invention in a heating device and is known to have a physiological absorption profile comparable to a classical cigarette,

- the increase of the proportion of the neutral form of nicotine in a reconstituted rooibos sheet having a pH above 7. The neutral form is volatile and thus is easily released during the manufacturing and mainly during the storage of said reconstituted rooibos sheet and of the consumables for heating device comprising said reconstituted rooibos sheet. Moreover, the neutral form gives more irritation and has a slower physiological absorption than the monoprotonated form, and

- the increase of the proportion of the diprotonated form of nicotine in a reconstituted rooibos sheet having a pH below 4.9. The diprotonated form is too stable to be efficiently released from said reconstituted rooibos sheet when the aerosol is generated so that said aerosol may comprise an unsatisfactory amount of nicotine. Moreover, the proportion of organic acid in free form also increases in said reconstituted rooibos sheet so that the aerosol generated from said reconstituted rooibos sheet may have an unpleasant acidic taste and may even have deleterious physiological effects in certain cases.

[0012] Moreover, the reconstituted rooibos sheet of the present invention has a warm color, which is an appealing color close to the one of reconstituted tobacco used for heating devices, and generates an aerosol having a neutral aroma.

[0013] Without wishing to be bound to any theory, the inventors are of the opinion that these results may be explained by the high amount of colored compounds and the low amount of aromatic compounds in the rooibos extract. [0014] Furthermore, the reconstituted rooibos sheet of the present invention generates a satisfactory amount of aerosol thanks to the aerosol-generating agent.

[0015] In another aspect, it is proposed a process for producing a reconstituted rooibos sheet as defined above, comprising the following steps: a) passing the rooibos fibers through a papermaking machine so as to produce a base web, b) forming a solution comprising:

- the rooibos extract,

- the aerosol-generating agent, and

- the nicotine and the organic acid, or the salt of nicotine, c) bringing the solution into contact with the base web to obtain a wet reconstituted rooibos sheet, and d) drying the wet reconstituted rooibos sheet to produce the reconstituted rooibos sheet.

Description of Embodiments

[0016] It is proposed a reconstituted rooibos sheet comprising:

- a fibrous support comprising rooibos fibers,

- an aerosol-generating agent, and

[0017] The pH of the reconstituted rooibos sheet of the present invention is measured as follows:

- grinding the reconstituted rooibos sheet to obtain particles below 1 mm,

- weighing 5.0 +/- 0.1 mg of grounded reconstituted rooibos sheet and mixing with 100.0 +/- 0.1 g of deionized water, the resistivity of the deionized water being around 18.2 Megohm/cm,

- stirring magnetically the sample in water during 15 min at a temperature of 20°C,

- measuring the pH.

[0018] The pH of the reconstituted rooibos sheet of the present invention may depend on the pKa of the organic acid. For example, the pH may range from 5.0 to 5.5 for an organic acid having a pKa lower than or equal to 4. Alternatively, the pH may range from 5.5 to 6.5 for an organic acid having a pKa higher than 4.

[0019] For the purposes of the present application, “salt of nicotine” denotes a form of nicotine characterized by the interaction between nicotine in monoprotonated form and an organic acid in carboxylate form. The structure of nicotine is such that it comprises two nitrogen atoms that are capable of accepting protons from the organic acid and, accordingly, it can be present in neutral form (the non-protonated form), monoprotonated form, and/or diprotonated form.

[0020] The total content by weight of solids of nicotine in the reconstituted rooibos sheet may be from 0.1 % to 4%, in particular from 0.5% to 3%, more particularly from 0.75% to 2.5%. [0021] Advantageously, the reconstituted rooibos sheet comprising the nicotine in such ranges generates an aerosol which enables the user to get an experience similar to the experience provided by the aerosol generated by a classical tobacco heating device and by a smoke generated by a combusted tobacco product.

[0022] The molar ratio of nicotine:organic acid may be from 1 :0.1 to 1 :10, in particular from 1 :0.4 to 1 :5, more particularly from 1 :0.5 to 1 :3.

[0023] Advantageously, the reconstituted rooibos sheet comprising the molar ratio in such ranges has a pH in the above-mentioned ranges.

[0024] Typically, the organic acid may have: a pKa of less than or equal to 5, in particular less than 4, more particularly less than 3 and a vapor pressure at 25°C from 10^-10 to 20 mmHg, in particular from 10^-8 to 10 mmHg, more particularly from 10^-8 to 1 mmHg, and/or a boiling point above or equal to 300°C or both.

[0025] Advantageously, the organic acid having such pKa and such vapor pressure and/or such boiling point:

- favors the formation of the salt of nicotine in the reconstituted rooibos sheet of the present invention with a low quantity of organic acid,

- limits the transfer of the organic acid in the aerosol generated by the reconstituted rooibos sheet of the present invention thereby limiting the acidic taste of said aerosol, and

- limits the loss of acid during the manufacture of the reconstituted rooibos sheet of the present invention.

[0026] The organic acid may have several pKa. For example, a dicarboxylic acid has two pKas. In this case, the lowest pKa of this organic acid may be less than or equal to 5, in particular less than 4, more particularly less than 3.

[0027] The organic acid may be alginic acid, aspartic acid, benzoic acid, citric acid, fumaric acid, glutamic acid, glycolic acid, lactic acid, levulinic acid, malic acid, pectic acid, pyruvic acid, salicylic acid, tartaric acid, glucuronic acid, galacturonic acid, myristic acid or mixtures thereof, in particular benzoic acid, citric acid, fumaric acid, glycolic acid, lactic acid, levulinic acid, malic acid, pyruvic acid, salicylic acid or mixtures thereof, more particularly citric acid, fumaric acid, glycolic acid, malic acid, lactic acid, pyruvic acid, salicylic acid or mixtures thereof.

[0028] For the purposes of the present application, "fibrous support" denotes a base web made of rooibos fibers, in particular refined fibers of rooibos. The base web is typically obtained by a papermaking process.

[0029] For the purposes of the present application, the term “rooibos extract” denotes all of the water- soluble products of the rooibos.

[0030] For the purposes of the present application, the term “aerosol-generating agent” denotes a compound which allows the formation of an aerosol when it is heated. [0031] For the purposes of the present application, the term “refined fibers of rooibos” denotes rooibos fibers which have undergone a refining step enabling fibrillation and/or cutting of the rooibos fibers. The refining step is conventionally carried out in a papermaking process, such as the papermaking process producing reconstituted papermaking tobacco. On the other hand, the refining step is not carried out in a process producing cast leaf reconstituted tobacco.

[0032] For example, the refined fibers of rooibos may have a degree Schopper-Riegler (°SR) from 15°SR to 75°SR, in particular from 20°SR to 65°SR, more particularly from 25°SR to 55°SR.

[0033] Typically, the content by weight of solids of the rooibos fibers included in the reconstituted rooibos sheet may be from 15% to 70%, in particular from 20% to 61 %, more particularly from 30% to 57%.

[0034] Typically, the fibrous support of the reconstituted rooibos sheet may also comprise cellulose- based plant fibers.

[0035] Cellulose-based plant fibers are fibers obtained by means of a chemical or mechanical or thermomechanical cooking process, such as wood pulp, hemp, or annual plants such as flax for example. A mixture of these cellulose-based plant fibers may also be used.

[0036] Advantageously, these cellulose-based plant fibers can improve the mechanical strength properties of the reconstituted rooibos sheet.

[0037] Typically, the cellulose-based plant fibers can represent from 0.5% to 20%, in particular from 3% to 17.5%, more particularly from 5% to 15% by weight of solids of the reconstituted rooibos sheet, the remaining fibers of the reconstituted rooibos sheet being the rooibos fibers.

[0038] Let SAG be the total content by weight of solids of the aerosol-generating agent included in the reconstituted rooibos sheet of the present invention. SAG may be from 10% to 40%, in particular from 12% to 35%, more particularly from 15% to 30%.

[0039] SAG may depend on the organic acid. For instance, SAG being from 15% to 20% is adapted to the organic acid soluble in a solvent, in particular in water. SAG being from 20% to 30% is adapted to the organic acid insoluble or slightly soluble in a solvent, in particular in water.

[0040] The aerosol generated from a reconstituted rooibos sheet having an SAG greater than the ranges mentioned above causes unwanted burning of the mouth and/or the throat (phenomenon known as “hot puff”).

[0041] The volume of the aerosol generated from a reconstituted rooibos sheet having an SAG lower than the ranges mentioned above is too low to be pleasant.

[0042] The aerosol-generating agent may be a polyol, a non-polyol or mixtures thereof. Typically, an aerosol generating agent that is a polyol may be glycerol, propylene glycol, sorbitol, triethylene glycol or mixtures thereof. An aerosol generating agent that is a non-polyol may be glyceryl diacetate, glyceryl triacetate, triethyl citrate, isopropyl myristate or mixtures thereof. [0043] The aerosol-generating agent may preferably be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol, glycerol being preferred.

[0044] The color of the reconstituted rooibos sheet may depend on the content by weight of solids of the rooibos extract included in the reconstituted rooibos sheet of the present invention.

[0045] Let S_P be the total content by weight of solids of the rooibos extract included in the reconstituted rooibos sheet of the present invention. S_P may be from 6% to 70%, in particular from 8% to 50%, more particularly from 10% to 35%.

[0046] Advantageously, an S_P within these ranges of values makes it possible to produce a reconstituted rooibos sheet having a warm color, and thus an attractive color.

[0047] To determine Sp, use may be made of the following method: the reconstituted rooibos sheet to be analyzed is ground in order to achieve a particle size of less than or equal to 1 mm. The reconstituted rooibos sheet is then mixed with boiling water for 45 minutes in order to extract all of the rooibos extract. Sp is calculated by the difference between the dry weight of the sample of reconstituted rooibos sheet to be analyzed and the dry weight of the fibrous residue after extraction.

[0048] The density of the reconstituted rooibos sheet of the present invention may be lower than 0.60 g/cm³, in particular from 0.20 g/cm³ to 0.59 g/m³, more particularly from 0,23 g/cm³ to 0.58 g/cm³.

[0049] Advantageously, a density within these ranges of values makes it possible to generate, at a comfortable draw resistance, an aerosol having constant high volume.

[0050] The density of the reconstituted rooibos sheet is calculated by dividing its basis weight by its thickness.

[0051] To determine the basis weight of the reconstituted rooibos sheet, the following method may be used: a sample of 0.25 m² is cut out with a template (dimensions: 57.5 x 43.5 cm) at approximately 15 cm from the edge of the reconstituted rooibos sheet to be analyzed. The sample is then folded in four and placed on a hotplate so as to be dried thereon in order to remove the water without removing the aerosol-generating agent.

The dried sample is then weighed to determine the basis weight of the reconstituted rooibos sheet.

[0052] To determine the thickness of the reconstituted rooibos sheet, the method described in standard NF EN ISO 534 (December 201 1 ) suitable for the reconstituted rooibos sheets may be used:

- the average thickness of the control parchment paper used to measure the thickness of the reconstituted rooibos sheet is measured (minimum of 6 measurements on a layer, on sites pinpointed on the paper),

- the reconstituted rooibos sheet sample is placed between 2 thicknesses of parchment paper,

- as soon as the probe of the micrometer has been put in place, there is a waiting period of 30 seconds before taking measurement (stabilization of the sample for thickness measurement), - a minimum of 6 measurements are taken at the sites pinpointed on the sheet of parchment paper,

- the calculated thickness of the reconstituted rooibos sheet is the average of the overall thickness measured (reconstituted rooibos sheet + 2 sheets of parchment paper) from which is subtracted 2 times the average thickness of the parchment paper.

[0053] Typically, the reconstituted rooibos sheet may have a basis weight of lower than 300 g/m², in particular from 20 g/m² to 250 g/m², more particularly from 80 g/m² to 200 g/m², even more particularly from 90 g/m² to 130 g/m².

[0054] Typically, the thickness of the fibrous support of the reconstituted rooibos sheet may be from 100 pm to 500 pm, in particular from 120 pm to 450 pm, more particularly from 140 pm to 425 pm, even more particularly from 180 pm to 400 pm.

[0055] It is also proposed a process for producing the reconstituted rooibos sheet of the present invention as defined above, comprising the following steps: a) passing the rooibos fibers through a papermaking machine so as to produce a base web, b) forming a solution comprising:

- the rooibos extract,

- the aerosol-generating agent, and

[0056] The rooibos fibers, the rooibos extract, the aerosol-generating agent, the organic acid and the salt of nicotine are as defined above in relation with the reconstituted rooibos sheet of the present invention.

[0057] In the solution formed during step b), the molar ratio of nicotine:organic acid may be from 1 :0.1 to 1 :10, in particular from 1 :0.4 to 1 :5, more particularly from 1 :0.5 to 1 :3.

[0058] The fibrous support may be produced using a papermaking machine. Therefore, the reconstituted rooibos sheet of the invention may be a reconstituted rooibos sheet obtainable by a papermaking process.

[0059] The pH of the solution formed during step b) and involved in step c) may be acidic, in particular from 4.0 to 6.5, more particularly from 5.0 to 6.0.

[0060] Advantageously, a solution having a pH in these ranges enables the production of the reconstituted rooibos sheet of the present invention.

[0061] The pH of the solution mainly depends on the amount of acid, nicotine and/or salt of nicotine in said solution. The skilled person knows how to adjust the amount of acid, nicotine and/or salt of nicotine in the solution so that said solution has a pH in the above range. [0062] The pH of the solution is determined using a pH electrode. The pH of the base web is determined by the method described above determining the pH of the reconstituted rooibos sheet of the present invention.

[0063] The rooibos fibers and the rooibos extract may be obtained in accordance with the following steps: e) mixing one or more rooibos parts with a solvent in order to extract the rooibos extract from the rooibos fibers, f) separating the rooibos extract from the rooibos fibers.

[0064] The rooibos extract and the rooibos fibers are therefore typically obtained by means of a dissociation process. During step e), one or more rooibos parts are mixed with a solvent, for example in a digester, in order to extract the rooibos extract from the rooibos fibers. During step f), the rooibos extract is separated from the rooibos fibers, for example by passing through a screw press, in order to isolate and obtain, on the one hand, the rooibos fibers and, on the other hand, the rooibos extract.

[0065] Typically, the solvent may be an apolar solvent, an aprotic polar solvent, a protic polar solvent, or a mixture thereof, in particular the solvent may be methanol, dichloromethane, ethanol, acetone, butanol, water or a mixture thereof, more particularly the solvent is ethanol, acetone, water or a mixture thereof.

[0066] The solvent may be an aqueous solvent, most particularly the solvent is water.

[0067] The skilled person knows how to adapt the temperature of the solvent during step e) to the rooibos parts to be treated. Typically, the temperature of the solvent during the treatment of a root or of a bark will be higher than the temperature of the solvent during the treatment of a leaf or a petal.

[0068] Typically, the temperature of the solvent during step e) may be from 10°C to 100°C, in particular from 30°C to 90°C, more particularly from 40°C to 80°C.

[0069] Typically, the rooibos fibers may be refined in a refiner and then involved in step a).

[0070] The solution may be formed during step b) by mixing in a solvent, in particular water, the organic acid, the nicotine, the aerosol-generating agent and the rooibos extract. Accordingly, the salt of nicotine is formed in-situ in the solution by reaction between the organic acid and the nicotine.

The organic acid may be added to the solvent before the nicotine. Indeed, it advantageously favors the formation of the salt of nicotine.

This step b) is adapted to an organic acid soluble in the solvent of the solution, in particular in water.

[0071] Alternatively, the solution may be formed during step b) by mixing in a solvent, in particular water, the salt of nicotine, the aerosol-generating agent and the rooibos extract. Accordingly, the salt of nicotine can be formed ex-situ or can be purchased before being added to the solvent, in particular water.

This alternative step b) is adapted to an organic acid insoluble or slightly soluble in the solvent of the solution, in particular in water. Such organic acid is, for example, salicylic acid, benzoic acid or mixtures thereof. [0072] Typically, the rooibos extract can be concentrated before being added to the solution during step b). A device such as a vacuum evaporation device can be used to concentrate the rooibos extract.

[0073] Typically, step c) can be carried out by impregnation or by spraying, in particular by impregnation. Typically, the impregnation can be carried out by means of a size press.

[0074] Typically, the drying step d) can be carried out by infrared ramp, American battery drying drums, hot-air drying in a tunnel drier, a vertical drier, a fluidized-bed drier, a pneumatic drier, in particular in a tunnel drier.

[0075] The reconstituted rooibos sheet produced at step d) may be shaped in particulate form, in the form of crimped sheet, in shredded.

[0076] The reconstituted rooibos sheet of the invention may be used in a heating device.

[0077] Thus, it is also proposed a consumable for a device for heating tobacco without burning it, comprising a reconstituted rooibos sheet according to the invention as defined above.

[0078] For the purposes of the present invention, the term "consumable" denotes the reconstituted rooibos sheet according to the invention as such, a pouch comprising the reconstituted rooibos sheet according to the invention, a capsule comprising the reconstituted rooibos sheet according to the invention or a stick for a heating device comprising the reconstituted rooibos sheet according to the invention.

[0079] For the purposes of the present application, the term “device for heating tobacco without burning it” denotes any device which allows the formation of an aerosol intended to be inhaled by a consumer. The aerosol replaces the smoke, thus allowing the user to inhale the tobacco aromas while at the same time very significantly reducing the user's exposure to the harmful constituents. Throughout the present application, the term “device for heating tobacco without burning it” may be replaced by the term “heating device”.

[0080] The consumable is adapted to be introduced into a dedicated lodging of the heating device, and those skilled in the art will know how to adapt the consumable according to dedicated lodging of the heating device.

[0081] The reconstituted rooibos sheet according to the invention, as consumable, can be shaped so as to be adapted to the dedicated lodging of the heating device. For example, it may be in particulate form, in the form of crimped sheet, in the form of shredded sheet, in particular in the form of shredded sheet having a width from 0.5 mm to 1 mm.

[0082] The pouch can be made of paper with an inner volume and the reconstituted rooibos sheet according to the invention is contained in the inner volume. In the inner volume, the reconstituted rooibos sheet according to the invention may be shaped, in particular in particulate form, in the form of creped sheet, in the form of shredded sheet.

[0083] The pouch may have a cylindrical form with two sealed ends and a third seal connecting the two sealed ends. [0084] Alternatively, the pouch may include a first layer of paper and a second layer of paper:

- coming from two different sheets of paper which are sealed on all sides, or

- coming from the same sheet of paper which is folded on one side and sealed on all the remaining sides.

[0085] The paper of the pouch may be cigarette paper, cigarette rolling paper, plant fiber paper, in particular cigarette paper.

[0086] The reconstituted rooibos sheet according to the invention may, for example, be in particulate form in a pouch or in a capsule.

[0087] The reconstituted rooibos sheet according to the invention may in particular be in the form of shredded sheet in a stick for a heating device.

[0088] According to one embodiment, the reconstituted rooibos sheet included in the consumable may be able to be obtained by the process according to the invention as defined above.

[0089] It is also proposed a use of a reconstituted rooibos sheet according to the invention as defined above or of a consumable according to the invention as defined above in a device for heating tobacco without burning it.

[0090] Typically, a heating device comprises, in the direction of the air flow, an air inlet, a heating body, a lodging intended to put in place and hold the reconstituted rooibos sheet of the invention comprising the aerosol-generating agent, and an air outlet intended to be introduced into the mouth of the user. The air inlet, the heating body, the lodging and the air outlet are typically connected at least fluidically to one another.

[0091] Typically, when the heating device is used, air is sucked into the heating device via the air inlet by the user; the air sucked in then passes through the heated portion so as to obtain heated air; on contact with the reconstituted rooibos sheet of the invention comprising the aerosol-generating agent, held in the lodging, an aerosol is formed by the heated air and is then inhaled by the user.

[0092] Furthermore, by virtue of the heating device, there is no combustion of the sheet. The user may therefore take advantage of the effect of nicotine while at the same time very significantly reducing their exposure to the harmful constituents.

[0093] The reconstituted rooibos sheet according to the invention as defined above may also be used as a wrapper paper.

Examples

[94] Example 1 : Manufacturing

[95] Example 1 A: the plant is rooibos and the organic acid is benzoic acid.

[96] A mixture of rooibos leaves is brought into contact with water in the laboratory in a water bath at 85°C with manual stirring for 30 minutes. The rooibos extracts are separated from the rooibos by centrifugation.

[97] Rooibos fibers are passed through a laboratory papermaking machine to obtain a base web. [98] The benzoic acid is mixed with nicotine to form a mixture. The rooibos extracts are mixed with this mixture. Glycerol is then added and mixed with this mixture to form a solution having a pH of 5.5.

[99] The solution is added to the base web by impregnation in a size press so as to obtain, after drying, a reconstituted rooibos sheet having a pH of 6.1 .

[100] In the reconstituted rooibos sheet:

- the total content by weight of solids of:

- nicotine is 1 .89%,

- rooibos extract is 10.4%, and

- glycerol is 17.1 %, and

- the molar ratio of nicotine: benzoic acid is 1 :1 .07.

[101 ] Comparative Example 1 : the plant is rooibos and no organic acid is added.

[102] A mixture of rooibos leaves is brought into contact with water in the laboratory in a water bath at 85°C with manual stirring for 30 minutes. The rooibos extracts are separated from the rooibos fibers by centrifugation.

[103] Rooibos fibres are passed through a laboratory papermaking machine to obtain a base web.

[104] The rooibos extracts are mixed with nicotine. The mixture of rooibos extracts and nicotine is mixed with glycerol to form a solution having a pH of 7.9.

[105] The solution is added to the base web by impregnation in a size press so as to obtain, after drying, a reconstituted rooibos sheet having a pH of 7.4.

[106] In the reconstituted rooibos sheet:

- the total content by weight of solids of:

- nicotine is 2.12%,

- rooibos extract is 12.2%, and

- glycerol is 17.6%.

[107] Example 2: Determination of nicotine release

[108] Example 2A: Room temperature ageing

[109] Reconstituted rooibos leaf of Example 1 A, Example 1 B and Comparative Example 1 are stored during 7 days in conditioned laboratory: 22°C, 60% Relative Humidity.

[110] The total content by weight of solids of nicotine of the three sample is then measured by Gas Chromatography coupled with Flame Ionization Detector (GC-FID). The contents are presented in Table 1 below.

[111] [Table 1 ]

[112] The results presented in Table 1 demonstrates that the nicotine is stabilized in the reconstituted plant sheet according to the present invention having a pH between 4.9 and 7.

Claims

[Claim 1] Process for producing a reconstituted rooibos sheet comprising the following steps: a) passing the rooibos fibers through a papermaking machine so as to produce a base web, b) forming a solution comprising:

- the rooibos extract,

- the aerosol-generating agent, and

- the nicotine and the organic acid, or the salt of nicotine; c) bringing the solution into contact with the base web to obtain a wet reconstituted rooibos sheet, and d) drying the wet reconstituted rooibos sheet to produce the reconstituted rooibos sheet, wherein the reconstituted rooibos sheet comprises:

- a fibrous support comprising rooibos fibers,

- an aerosol-generating agent, and

[Claim 2] Process according to claim 1 , wherein the organic acid has: a pKa of less than or equal to 5, and a vapor pressure at 25°C from 1 O^-10 mm to 20 mm of Hg, a boiling point above or equal to 300°C or both.

[Claim 3] Process according to claim 1 or claim 2, wherein the organic acid is alginic acid, aspartic acid, benzoic acid, citric acid, fumaric acid, glutamic acid, glycolic acid, lactic acid, levulinic acid, malic acid, pectic acid, pyruvic acid, salicylic acid, tartaric acid, glucuronic acid, galacturonic acid, myristic acid or mixtures thereof.

[Claim 4] Process according to any one of claims 1 to 3, wherein the total content by weight of solids of nicotine of the reconstituted rooibos sheet is from 0.1 % to 4%.

[Claim 5] Process according to any one of claims 1 to 4, wherein the molar ratio of nicotine:organic acid of the reconstituted rooibos sheet is from 1 :0.1 to 1 :10.

[Claim 6] Process according to any one of claims 1 to 5, wherein the total content by weight of solids of the aerosol-generating agent of the reconstituted rooibos is from 10% to 40%.

[Claim 7] Process according to any one of claims 1 to 6, wherein the total content by weight of solids of the rooibos extract of the reconstituted rooibos is from 6% to 70%.

[Claim 8] Process according to any one of claims 1 to 7, wherein the pH of the solution is acidic.

[Claim 9] Process according to any one claims 1 to 8 wherein, during step b), the solution is formed by: - mixing in a solvent, the organic acid, the nicotine, the aerosol-generating agent and the rooibos extract, or

- mixing in a solvent, the salt of nicotine, the aerosol-generating agent and the rooibos extract.