CN113197324B

CN113197324B - A gel capable of stabilizing fragrant substances

Info

Publication number: CN113197324B
Application number: CN202110518647.3A
Authority: CN
Inventors: 韩熠; 赵伟; 巩效伟; 杨柳; 朱东来; 吕茜; 洪鎏; 尚善斋; 段沅杏; 秦云华; 陈永宽
Original assignee: China Tobacco Yunnan Industrial Co Ltd
Current assignee: China Tobacco Yunnan Industrial Co Ltd
Priority date: 2021-05-12
Filing date: 2021-05-12
Publication date: 2022-11-04
Anticipated expiration: 2041-05-12
Also published as: CN113197324A

Abstract

The invention belongs to the field of supramolecular gel, and particularly relates to gel capable of stabilizing fragrant substances. The gel comprises a racemic nicotine malate gelling agent and a flavor substance and an organic solvent dispersed in the racemic nicotine malate gelling agent. The invention takes the nicotine salt gel as the carrier of the flavor substance and the smoke agent, reduces the requirement on the loading function of the reconstituted tobacco sheet base and reduces the use of a large amount of loading filler. For the reconstituted tobacco by the thick paste method, even if higher moisture needs to be removed during drying, because the fragrant substances and the smoke agent are fixed in the gel, the loss of the fragrant substances and the smoke agent can be effectively avoided while the moisture is removed by adopting measures such as low-temperature multi-stage drying and the like.

Description

A gel capable of stabilizing fragrant substances

Technical Field

The invention belongs to the field of supramolecular gel, and particularly relates to gel capable of stabilizing fragrant substances.

Background

The basic nicotine can be reacted with the carboxylic group of the organic acid to form a nicotine carboxylate. Nicotine comprises a pyridine ring and an azole ring, wherein the azole ring nitrogen is more basic and tends to react with the carboxyl group of carboxylic acid to form nicotine salt, while the pyridine ring nitrogen is less basic and substantially cannot be ionized and can only be bound to carboxylic acid by non-covalent action such as hydrogen bond. The tobacco leaves naturally contain various carboxylic acid nicotine salts, and the nicotine salts can be divided into 1 acid-base ratio, 2. Wherein the common nicotine carboxylate comprises nicotine tartrate, racemic nicotine malate, nicotine oxalate, and nicotine benzoate.

Studies have shown that two complex chemical reactions occur when nicotine is released from nicotine salts: the first reaction includes dissociation and/or dehydration and decomposition of carboxylic acid anions; the second reaction involves proton transfer between different nicotine forms, disproportionation of a single protonated salt to a mixture of a double protic salt and free nicotine, and evaporation of the free nicotine to achieve a disproportionation equilibrium. Experiments prove that most nicotine salts can release nicotine at two different temperature ranges (110-125 ℃ and 160-210 ℃), wherein the nicotine at the low temperature section is from non-protonated nicotine formed by disproportionation reaction of nicotine salt, and the nicotine at the high temperature section is from non-protonated nicotine obtained by further decomposition/dissociation of double-protonated nicotine in the disproportionation product. Specifically, there are 3 intervals for the temperature of nicotine released by heating of various nicotine salts: about 115 ℃ (evaporation/volatilization of non-protonated nicotine (free nicotine)), about 165 ℃ (disproportionation of single protonated nicotine salt), and about 200 ℃ (decomposition/dissociation of double-protonated nicotine salt).

The synthesized nicotine salt can be directly added into the electronic cigarette or the heating cigarette to achieve the effects of supplementing the nicotine amount and obtaining the physiological feeling similar to that of smoking and smoking cigarettes. If the heating temperature of the tobacco leaves exceeds 250 ℃, the nicotine content in the smoke is similar to that in the smoke of the burning and sucking type cigarette. Meanwhile, when the heating temperature of the tobacco leaves does not exceed 350 ℃, the generation of harmful and potentially harmful ingredients (HPHCs) is obviously reduced compared with the smoking type cigarette. Importantly, the transfer rate of nicotine from the non-protonated (free) nicotine and nicotine carboxylate salts to the gas phase is comparable in the 250-300 c range. Heating cigarettes avoids the high temperatures of tobacco combustion, delivering nicotine levels similar to smoking cigarettes, but with lower average levels of harmful components.

The current major problems and drawbacks of heating cigarettes:

the heating cigarette is different from the burning type cigarette and is characterized in that: on one hand, volatile flavor components are evaporated into the gas phase to escape out of cigarettes in the preheating stage along with the transfer of nicotine, so that the fragrance attenuation of the later stage in smoking is serious; on the other hand, the tobacco itself contains a large amount of polycarboxylic acid nicotine salt (such as malic acid and racemic malic acid nicotine salt), when the nicotine salt releases nicotine, due to the poor thermal stability of the polycarboxylic acid itself, the elimination reaction occurs due to dehydration or decarboxylation to form a weakly acidic product such as monocarboxylic acid (such as acetic acid), and in the process, the problems of small smoke amount before smoking, mouth burning of smoke, obvious sour feeling and the like are caused due to the slow accumulation of moisture and acidity.

The reconstituted tobacco leaves have the characteristics of stronger plasticity, homogenization and higher adjustable level while keeping the active ingredients of the natural tobacco leaves, so the reconstituted tobacco leaves are one of the main tobacco section materials of the existing heating cigarettes. The tobacco section of mainstream heating cigarette is mostly manufactured by adopting the processes of paper making method and thick paste method. The papermaking process is influenced by the coating rate, the smoke amount and the fragrance amount of the papermaking process are slightly low, and the high-content (12-20%) smoke agent is mainly coated on the surface of the reconstituted tobacco and is easy to leach and absorb moisture. In order to improve the aroma amount of the reconstituted tobacco, refined processing such as tobacco solvent extraction, molecular distillation and the like is usually adopted to prepare tobacco extract with high aroma amount and high nicotine amount and add the tobacco extract into the coating liquid, so that the process is complicated and the manufacturing cost is high; in order to meet the loading function of the chip base, a more complex special chip base needs to be developed; the reconstituted tobacco has high surface viscosity and poor elasticity, and the difficulty of the subsequent shredding process is increased. The thick pulp method reconstituted tobacco has high pulp moisture (about 80%) during forming, and high moisture needs to be removed during drying, so that loss of aroma components and smoke agents is easily caused. In conclusion, reconstituted tobacco for cigarette heating by a paper making method and a thick stock method mainly has the problems of leaching from tobacco sections, moisture absorption and the like caused by low aroma amount and smoke amount and high smoke agent, which directly affect the product quality and the smoking sensory quality.

The main problems and defects of the electronic cigarette liquid at present are as follows:

the nicotine originally used in e-cigarette smoke solutions was referred to as "free base" nicotine. The free base nicotine is volatile. As a result, when a consumer inhales the e-vaping sol, nicotine is likely to be released from the aerosol particles in gaseous form, deposited in the oral/upper respiratory tract, and absorbed by the blood. Absorption in the oral/upper respiratory tract is slower than in conventional cigarettes, and pharmacokinetic studies have shown that they are closer to Nicotine Replacement Therapy (NRT) products than in conventional cigarettes. For this reason, tobacco solutions containing nicotine salts have been introduced. The nicotine salt is less volatile than the free base nicotine. Pharmacokinetic studies have shown that nicotine carboxylates can deliver nicotine through the lungs, increasing the rate of absorption without exceeding the maximum nicotine concentration of conventional cigarettes, while having acceptable subjective satisfaction and ease of smoking. Currently, a nicotine salt that is representative in commercially available electronic cigarettes is nicotine benzoate.

Although nicotine salts have been widely used in electronic cigarette liquid, the current electronic cigarettes containing nicotine salts still have the following major problems in the sense of sense: when the nicotine salt is heated and decomposed to form free nicotine and delivered to atomized steam, the release behavior of the nicotine by mouth is inconsistent with that of the aroma component, the key aroma component and the nicotine are difficult to realize the synergistic delivery, and the nicotine can not bring matched characteristic aroma while bringing the physiological satisfaction of the nicotine, so that the sensory feelings of the nicotine and the aroma substance are weak, mutually cover or even mutually repel, especially for the volatile characteristic aroma substance, the nicotine and the aroma substance can not be stably released (usually the release amount by mouth is gradually reduced) in the whole smoking process, and the discordance is particularly obvious. For this reason, this may be because: from the material aspect, the nicotine salt and the essence flavor in the tobacco liquid belong to different systems, the nicotine salt and the essence flavor belong to a nicotine release system, the essence flavor belongs to a flavor release system, a medium which can connect the nicotine salt and the flavor release system into a whole does not exist in the tobacco liquid, and the nicotine salt and the flavor release system respectively have the atomizing behaviors at the same atomizing temperature; from an organoleptic point of view, nicotine salts mainly provide suitable physiological satisfaction and relaxation, flavors and fragrances mainly provide inhalation and eating flavors with characteristic tastes through evaporation, and the organoleptic characteristics are also separated during smoking because of different atomization behaviors of the two. Another common problem with e-cigarettes is: in the process of storing the cigarette liquid or the cigarette cartridge, the problem of volatilization loss of the aroma components is inevitable, and even in a closed cigarette cartridge, the problem of deterioration of aroma substances is also existed. Although the volatile aroma components can be wrapped by the microcapsule technology at present, because the microcapsule uses carbohydrate such as cyclodextrin and the like as a wall material, burnt taste and uncomfortable feeling caused by the adhesion of the wall material on a heating element can be generated at the heating temperature of the electronic cigarette. The stabilization of flavor substances, especially volatile flavor substances, in cigarette liquid is still a major problem to be solved in electronic cigarettes.

Disclosure of Invention

In order to overcome the defects of the heated cigarettes and the electronic cigarettes, the invention discloses a nicotine salt gelling agent-based aroma-carrying supramolecular gel for the first time, which takes a fiber network formed by self-assembly of a small amount of nicotine salt gelling agent as a matrix, carries a large amount of solvent (smoke agent) dissolved with aroma substances, and can be applied to the fields of the heated cigarettes and the electronic cigarettes by utilizing the inherent high aroma-carrying amount, high solvent (smoke agent) carrying amount, heat reversible characteristics and supramolecular network structure stability different from the conventional nicotine salt molecules of the gel.

Interpretation of terms:

supramolecular gels: supramolecular gels are composed of small molecules (M), commonly referred to as small molecular weight gelling agents (LMWGs) _w Less than 3000). The compounds are used for preparing supramolecular gelThe LMWGs self-assemble by various non-covalent interactions (such as hydrogen bonding, pi-pi stacking, electrostatic interactions, complexation, and hydrophobic interactions, etc.) to form a self-assembled fiber network (SAFINs) to immobilize the solvent molecules. Physical gels derived from small molecular weight organogelators (LMOGs) are generally thermoreversible (reversible sol-gel transformation occurs upon heating and cooling). When the gelling agent containing the solution is cooled, growth of one-dimensional (1D) fibers is promoted, which self-assembles into complex three-dimensional (3D) SAFINs in a manner that allows the solvent molecules to be immobilized therein by capillary action to form a gel.

The invention provides a gel capable of stabilizing a fragrant substance or a fragrant supramolecular gel based on a racemic nicotine malate salt gelatinizer, wherein the gel comprises the racemic nicotine malate salt gelatinizer, the fragrant substance and an organic solvent which are dispersed in the racemic nicotine malate salt gelatinizer;

the racemic malic acid nicotine salt gelatinizer is a three-dimensional network structure formed by self-assembly of one-dimensional fibers, the one-dimensional fiber structure is formed by connecting a plurality of racemic malic acid nicotine salt supramolecular structural units formed between racemic malic acid and nicotine, and the connection between the racemic malic acid nicotine salt supramolecular structural units is as follows:

the principle of forming the racemic malic acid nicotine salt gelatinizer is as follows: nicotine and carboxylic acid molecules are combined into a supramolecular structure unit through synthons, then the supramolecular structure unit is connected into a one-dimensional fiber structure through intermolecular force such as hydrogen bond, and then the one-dimensional fiber structure is self-assembled to form a three-dimensional network structure.

Preferably, the fragrance substance is selected from: beta-damascenone, nootkatone, beta-damascenone, perillyl alcohol, citronellol, linalool, leaf alcohol, nerol, geraniol, beta-phenylethyl alcohol, citronellal, menthol, benzyl alcohol, solanone, geranylacetone, megastigmatrienone, beta-ionone, citral, safranal, phenylacetaldehyde, methyl hexanoate, ethyl hexanoate, amyl hexanoate, isoamyl hexanoate, ethyl heptanoate, methyl benzoate, ethyl isovalerate, methyl salicylate, isovalerate, 3-methylvalerate, alpha-phellandrene, limonene, bisabolene, and ocimenene.

Preferably, the organic solvent is selected from 1, 2-or 1, 3-propanediol or glycerol.

The second aspect of the present invention provides a method for preparing a gel capable of stabilizing a fragrant substance, comprising the steps of:

step 1, preparing a gelling agent: respectively dissolving racemic malic acid and nicotine in ethanol according to a molar ratio of 2 to 1, stirring at room temperature until completely dissolving to respectively obtain a racemic malic acid solution and a nicotine solution, then fully mixing the two solutions to obtain a mixed solution, heating the mixed solution to reflux, reacting for more than 30min, carrying out rotary evaporation, and drying the product obtained by rotary evaporation at 30-40 ℃ for 1h to obtain a racemic malic acid nicotine salt gelling agent;

in the step 1, ethanol is selected as an organic solvent because racemic malic acid is easily soluble in ethanol and nicotine is soluble in ethanol;

step 2, preparation of gel:

dissolving the fragrant substance with organic solvent to obtain a fragrant substance-containing solvent; and then adding the flavor-containing substance into the racemic nicotine malate salt gelling agent obtained in the step 1, dissolving the solvent by heating and stirring or ultrasonic treatment, and standing in an ice water bath to form gel.

The ice-water bath temperature is preferably: 0 to 5 degrees celsius, such as 0 degrees celsius, 1 degree celsius, 2 degrees celsius, 3 degrees celsius, 4 degrees celsius, 5 degrees celsius.

Preferably, in the step 1, the mass volume ratio of the racemic malic acid to the ethanol is 1g.

Theoretically, ethanol could be replaced by methanol or acetone, but methanol is more toxic and acetone is too volatile and therefore is not generally used.

Preferably, in the step 2, the mass volume ratio of the flavor substance to the organic solvent is 1g to be 20-30 mL, the mass volume ratio of the racemic malic acid nicotine salt gelatinizer to the flavor substance-containing solvent is 1g to be 20-30 mL, the temperature of the ice water bath is 4 ℃, and the standing time in the ice water bath is 1-3 h.

Since the amounts of fragrance and gelling agent required are relatively small and the amount of solvent is relatively large, it is easier to handle in practice with a mass to volume ratio.

The fragrance substance of the invention is a medium polarity or slightly strong polarity substance, and belongs to volatile fragrance substances. Standing in ice water bath to maintain the stability of volatile flavor substances.

The organic solvent in step 2 of the present invention is selected from one or more of 1, 2-propylene glycol, 1, 3-propylene glycol and glycerol for the following reasons: the gelling agent has larger polarity (hydrogen bonds with larger polarity are used as driving force for forming the gelling agent), and is easy to form a uniform system with a solvent 1, 2-propylene glycol or 1, 3-propylene glycol or glycerol with larger polarity when being heated; secondly, the solubility of the polar fragrant substance in the polar solvent 1, 2-propylene glycol or 1, 3-propylene glycol or glycerol is larger; thirdly, the gelling agent has stronger polarity and is easy to form gel in a solvent 1, 2-propylene glycol, 1, 3-propylene glycol or glycerol with similar polarity, so that the gelation failure caused by phase separation during cooling gelation is avoided; and the 1, 2-propylene glycol or the 1, 3-propylene glycol or the glycerol can be used as the smoke agent.

More preferably, the organic solvent of step 2 of the present invention is selected from: (1) 1, 2-propylene glycol or (2) a mixed solvent of 1, 2-propylene glycol and glycerol. The reason is that: glycerol is too viscous to be suitable for use in this system by mixing with 1, 2-propanediol. 1, 3-propanediol is less safe than 1, 2-propanediol, and 1, 2-propanediol is generally preferred.

Still preferably, the content by volume of the 1, 2-propanediol in the mixed solvent of the 1, 2-propanediol and glycerin is more than 30%.

Since the nicotinic pyrrole nitrogen (pKa 8.01) is more basic than the pyridine nitrogen (pKa 3.10), the carboxylic acid is easily degradedForming carboxylate with pyrrole nitrogen (this is the salt forming mechanism of conventional nicotine salt, and charge-assisted hydrogen bond (N) with pyrrole nitrogen-carboxylic acid explained by crystal engineering ⁺ …H-O ^- ) Synthon theory) that contains hydrogen bonding surfaces and is no longer self-compensating (i.e., forms carboxylic acid dimers).

The key or difficulty of the preparation process of the invention is to avoid the formation of nicotine salt, and the method mainly adopts the following method to avoid salt formation:

1. the invention reduces ionization reaction of carboxylic acid in racemic malic acid to avoid forming nicotine salt by using organic solvent instead of water;

2. in a conventional process for preparing a nicotine salt: direct heating to promote acid-base neutralization. The invention adopts reflux and rotary evaporation to prevent violent salt forming reaction so as to prepare the gelling agent.

3. In a conventional process for preparing a nicotine salt: the freeze drying method is adopted to rapidly remove free or crystal water contained in the nicotine salt. The invention adopts a rotary evaporation method to remove the solvent ethanol in the reaction system to obtain the gelling agent.

Preferably, the fragrance substance is selected from: beta-damascenone, nootkatone, beta-dihydrodamascenone, perillyl alcohol, citronellol, linalool, leaf alcohol, nerol, geraniol, beta-phenylethyl alcohol, citronellal, menthol, benzyl alcohol, solanone, geranylacetone, megastigmatrienone, beta-ionone, citral, safranal, phenylacetaldehyde, methyl hexanoate, ethyl hexanoate, amyl hexanoate, isoamyl hexanoate, ethyl heptanoate, methyl benzoate, ethyl isovalerate, methyl salicylate, isovaleric acid, 3-methylpentanoic acid, alpha-phellandrene, limonene, bisabolene, and ocimenene.

In a third aspect, the present invention provides the use of a gel comprising a flavour and a racemic nicotine malate salt gelling agent as described in the first aspect, in the manufacture of a heated non-burning cigarette or e-cigarette.

Preferably, when the gel is used in a cigarette which is not burnt under heating, the nicotine release time is effectively prolonged, so that the physiological feeling brought by nicotine is more continuous, the problem of smoke agent leaching or moisture absorption is avoided, and the phenomenon that the fragrance is lost too quickly is also avoided;

when the gel is used in an electronic cigarette, the aroma component and nicotine can be stabilized, and the synergistic release of the aroma component and nicotine during heating and atomization is ensured.

The way the gel is used in an electronic cigarette is: the nicotine salt gel microparticles are added into a tobacco liquid solvent (smoking agent) system or a tobacco liquid, or the nicotine salt fragrance-carrying gel is directly dispersed in the tobacco liquid solvent (smoking agent) or the tobacco liquid to form a uniform system, so that the fragrance-generating components and nicotine are stabilized, and the synergistic release of the fragrance-generating components and nicotine during heating and atomization is ensured.

The principle of the invention is as follows:

the invention obtains the gelling agent by selecting the specific carboxylic acid racemic malic acid to react with nicotine and controlling the reaction conditions, such as solvent type, heating mode, post-processing mode, reactant proportion and other factors.

The supramolecular synthons constituting the supramolecular building blocks capable of forming stable gels are key to the formation of the above-mentioned gelling agents. According to the concept of crystal engineering, if the same type of supramolecular interaction can be reliably and reproducibly created between basic building blocks (molecules) with specific functional groups, the non-covalent bonds connecting these basic building blocks are called supramolecular synthons. Increasing the hydrogen bonding sites facilitates the assembly of the gelling agent molecules into a gel network.

The present invention forms a carboxylic acid dimer hydrogen bond synthon between racemic malic acid molecules (figure 1), a pyridine nitrogen-carboxylic acid synthon between racemic malic acid and nicotine (figure 2) and a pyrrole nitrogen-carboxylic acid charge assisted hydrogen bond synthon (N) ⁺ …H-O ^- ) (3 in FIG. 3), these homo-and hetero-supramolecular synthons constitute the basic structural units of the gelator molecules according to the invention. These homo-and hetero-supramolecular synthons tend to orient to drive the self-assembly of small molecule gelling agents of nicotinates, which in turn produce one-dimensional fibrous aggregates and entangle to form self-assembled fiber networks (SAFINs) that immobilize fluids by capillary action or surface tensionForming a gel; meanwhile, the nicotine pyridyl is used as a proton acceptor and can form hydrogen bond with a proton donor (such as COOH), and the structure can be adjusted for self-assembly; in addition, the stronger basicity of the pyrrole-nicotinyl ring is known to cause it to preferentially undergo acid-base salt formation with carboxylic acids, and the resulting charge assists in strong (about 40-190 kJ/mol) hydrogen bonding to orient, enhancing the actual stability of the gel.

According to the theory of molecular engineering, gelation needs to satisfy the following conditions in 3 aspects: (1) The strong and directional supramolecular action promotes the aggregation of gelling agent molecules to form fibers; (2) The ability to wind or interweave to form fibers (i.e., the ability to form SAFINs); (3) a factor preventing pure crystallization of the gelling agent. The various hydrogen-bonded supramolecular synthons described above promote (1) and (2), while long hydrocarbon chains can promote (3).

According to the Etter rules of thumb for determining preferential hydrogen bonding patterns in organic solids, in the nicotine carboxylate gelling agents described herein, because the pyridine nitrogen atom of nicotine is a better proton acceptor than the carbonyl oxygen atom, the pyridine nitrogen-carboxylic acid hetero synthon (fig. 2) assembles in preference to the carboxylic acid dimer homo synthon (fig. 1).

By controlling the carboxylic acid with the appropriate number of carboxyl groups and the appropriate acid-base ratio, adjusting the competition of the two synthons is very important for directing the preparation of the gel. The acid-base ratio of the racemic malic acid to nicotine is 2.

The method for measuring the critical gelation concentration CGC is a test tube inversion method: adding gelling agents with different masses into a test tube added with 1g of solvent, heating until the gelling agents are completely melted, standing at room temperature, inverting the test tube until the material is not deformed after condensation, and regarding the material as gel formation, wherein the minimum mass percent of the gelling agents required for forming the gel is the critical gelation concentration of the gelling agents.

Sol-gel transition temperature T _gel The determination method is a falling ball method: 0.5g of the gel was placed in a test tube (15 mmX100 mm), and a glass bead having a mass of 214.6mg was placed on the gel surface. Will try outThe tube was heated while immersed in an oil bath, and the temperature recorded when the glass ball fell to the bottom of the test tube was T _gel 。

Compared with the prior art, the invention has the following beneficial effects:

1. the invention uses racemic malic acid and nicotine to prepare a gelling agent with a supramolecular network structure and a fragrance-carrying supramolecular gel for the first time, and the gel realizes the common fixation and the synergistic release of nicotine and a fragrance component.

The critical gelation concentration CGC of the gelling agent is calculated to be 0.83wt%, namely when the gel is formed, the minimum mass fraction of the gelling agent in the gel is 0.83wt%. The sol-gel transition temperature (T) of the gelling agent was determined _gel ) The temperature is 80 deg.C, the material is in sol or solution state at atmospheric pressure and above 80 deg.C, and the material is in gel state at below 80 deg.C. Because of the inherent thermal reversible property of the supramolecular gel, the flavor substances (especially volatile flavor substances) are encapsulated in the gel network of the nicotine salt, and only when the heating temperature is more than or equal to T _gel When the temperature is lower than T, the gel is molten to form sol or solution _gel In the meantime, the molten sol or solution undergoes reversible gelation and returns to a gel state. Therefore, the fragrant substance is stably fixed in the gel network at normal temperature, and the storage stability of the fragrant component is effectively improved.

2. The high load rate of the supramolecular gel on the solvent (smoke agent) and the aroma substances dissolved in the solvent can make up the problem of insufficient aroma quantity and smoke quantity of the heated cigarette, and realize effective supplement of the aroma quantity and the smoke quantity; in particular, by fixing the volatile flavor in the nicotine salt gel releasing nicotine at a high temperature stage, the volatile loss of the flavor at a preheating stage or a low temperature heating stage can be reduced and the decayed flavor can be supplemented at a later stage in the smoking.

3. Unlike the conventional polycarboxylic acid nicotine salt, in the racemic malic acid nicotine salt gelling agent, carboxyl groups form a carboxylic acid dimer (hydrogen bond ring) homosynthon (figure 1) besides a hetero synthon with pyridine nitrogen and pyrrole nitrogen, and supermolecular structural units formed by the synthons are self-assembled into a stable fiber network, so that the number of free carboxyl groups is reduced, even the free carboxyl groups do not exist, the opportunity of generating volatile monocarboxylic acid due to dehydration and decarboxylation in a preheating stage or a low-temperature heating stage of a heated cigarette is inhibited, and the phenomena of small smoke amount at the front section of smoking, burning of smoke, obvious acid feeling and the like caused by slow accumulation of moisture and acidity are reduced.

4. One of the intrinsic properties of supramolecular gels is: the amount of gellant used is minimal, while the amount of gel loading substance is extremely large (e.g., one molecule of gellant can bind thousands of molecules of solvent). Thus, the net effect is that a small amount of nicotine salt gelling agent can be combined with the aroma component dissolved in the solvent by fixing a large amount of solvent. In the field of heating cigarettes, such advantages are reflected in: because the coating rate of the traditional coating liquid is not high, the using amount of the coating liquid is increased or tobacco extract is added to obtain enough aroma amount and smoke amount, and the gel is loaded with high content of smoke agent and aroma component, the coating amount of the applied gel is lower than that of the applied coating liquid, which is beneficial to reducing raw material and manufacturing cost.

5. In addition, the 1, 2-propylene glycol used as the solvent of the gel is a smoke agent, the smoke agent is locked in the gel at normal temperature, the problem of smoke agent leaching or moisture absorption is not easy to occur, and the too fast loss of fragrance is avoided.

6. Because the nicotine salt gel is more stable than pure nicotine salt in structure, the upper limit of the release temperature of nicotine is higher than that of nicotine in the conventional nicotine salt, so that the release loss of nicotine before 210 ℃ can be reduced, the release time of nicotine is effectively prolonged, and the physiological feeling brought by nicotine is more continuous.

7. Due to the inherent thermoreversible characteristic of the supramolecular gel, when the gel is applied to the reconstituted tobacco for the heated cigarette, the gel is heated and melted to be converted into sol or solution and then applied to the reconstituted tobacco, and then the sol or solution is cooled to be gelatinized and combined with the reconstituted tobacco, so that the processing of the reconstituted tobacco and the formation of the gel are synchronous, and the working procedures are reduced.

8. The nicotine salt gel is used as a carrier of the flavor substance and the smoke agent, the requirement on the loading function of the reconstituted tobacco sheet base is reduced, and the use of a large amount of loading fillers is reduced.

9. For the reconstituted tobacco by the thick paste method, even if higher moisture needs to be removed during drying, because the fragrant substances and the smoke agent are fixed in the gel, the loss of the fragrant substances and the smoke agent can be effectively avoided while the moisture is removed by adopting measures such as low-temperature multi-stage drying and the like.

10. The conventional reconstituted tobacco has high surface viscosity and poor elasticity due to the fact that a large amount of smoke agents are applied to the surface of the reconstituted tobacco, and provides high requirements for a subsequent shredding process.

11. Since the raw materials for preparing the gelling agent are nicotine and carboxylic acid themselves, and no other components are added, no residue is left after heating or no bad smell is generated by adhesion to the heat-generating element.

12. When the nicotine salt gel is applied to the electronic cigarette, the nicotine salt gel microparticles are added into a cigarette liquid solvent (smoking agent) system or a cigarette liquid, or the nicotine salt-loaded gel is directly dispersed in the cigarette liquid solvent (smoking agent) or the cigarette liquid to form a uniform system, so that the aroma component and the nicotine are stabilized, and the synergistic release of the aroma component and the nicotine during heating and atomization is ensured. In addition, the nicotine salt supermolecule aroma-carrying gel obtained by regulating the adaptability of the nicotine salt gelling agent and the aroma-carrying substances has the characteristics of high aroma-carrying capacity, high solvent (smoke agent) carrying capacity, thermal reversibility and the like. The invention uses a gel medium to associate the originally separated nicotine salt system and the flavor system to form a new substance form (gel) and to associate the originally separated physiological satisfaction and relaxation to the characteristic taste of the mouth-eating taste to form a new comprehensive sensory perception (resulting from the synergistic release of nicotine and flavor substances). Through the recombination of the substance level and the sensory level, the nicotine and the aroma components are released synergistically, so that the synergistic sensory experience is obtained.

13. The known nicotine salt releases nicotine in a temperature range comprising two intervals of 110-125 c and 160-210 c. When the nicotine salt gel is used for replacing nicotine salt in electronic cigarettes, due to the structural stability of the supramolecular gel, nicotine is equivalently fixed by the gel structure, the rapid release of the nicotine is prevented, and the release temperature T of the nicotine is higher than that of the gel _nic The range is higher than that of the conventional nicotine salt and is close to or consistent with the working temperature of the electronic cigarette, the nicotine inhalation amount at the working temperature of the electronic cigarette is improved, and the nicotine release duration is longer.

14. The specific fragrance-carrying supermolecule gel system comprehensively matches the factors such as the thermal stability of a nicotine salt gelling agent, a nicotine release temperature interval, the volatility of fragrance substances fixed by the gel, the properties of a solvent and the like. In particular, the present invention fixes a volatile fragrance substance to a substance having good thermal stability (T) _gel High value) and release of nicotine (T) in the high temperature region _nic Higher value) can overcome the defect that volatile flavor substances are released in a large amount in the front section of smoking and the fragrance in the rear section of smoking is thin.

15. When the nicotine salt gel is applied to the electronic cigarette, when the electronic cigarette is not sucked or used, the melted gel is condensed to be gelled due to the heat reversible characteristic of the gel, so that the nicotine is re-stabilized through the recovery of the nicotine salt gelling agent network, and the flavor substance is re-fixed in the gel to be stabilized, thereby reducing the loss of the nicotine and the flavor substance in the process of warming and cooling the electronic cigarette.

16. Interconversion of gel and solution/sol phases is only related to disassembly and assembly of supramolecular structural units, chemical components are not changed in the phase change process, and stability and consistency of sensory experience of the electronic cigarette are facilitated.

17. The reconstituted tobacco loaded with the coating liquid is high in fragrance loading, high in smoke generation and low in coating weight. The traditional reconstituted tobacco is of a type with low aroma loading, low smoke generation and high coating weight. The concrete expression is as follows: when the coating liquid is cooled to be gelatinized, the fragrant substances and the smoke agent are locked in the gel and separated from the moisture, and the moisture outside the gel can be removed during subsequent heating and drying to control the moisture content, so that the loss of the perfume in the gel is avoided, and the amount of the coating liquid applied to reach the required fragrance amount and smoke amount is lower. The novel HNB reconstituted tobacco with high fragrance amount and high smoke amount different from the conventional HNB reconstituted tobacco is prepared by adopting the high-proportion gel coating liquid (namely the gel occupation ratio in the coating liquid is high, namely the coating liquid takes gel as the main component, so that the coating amount is reduced), the fixed spice and the smoke agent can be fully utilized, the coating amount is greatly reduced, the utilization rate of the coating liquid is increased, and the application value of the gel is embodied. In the conventional coating liquid, the perfume and the smoke agent have no medium for locking the perfume and the smoke agent, and when the water content is controlled by heating and drying, the perfume, the water and the smoke agent are all in an open state, so that the water is removed, and part of the fragrant substances and the smoke agent are removed, so that the loss is compensated by adding a high content of the perfume (such as 7-8%) and the smoke agent (such as 20%), and as a result, the amount of the coating liquid applied for achieving the required amount of the perfume and the smoke amount is higher, and the waste is larger.

Drawings

FIG. 1 is a schematic diagram of a carboxylic acid dimer synthon according to the present invention.

FIG. 2 is a schematic diagram of a pyridine-carboxylic acid synthon according to the present invention.

FIG. 3 shows racemic nicotine malate supramolecular structural units and fiber networks of the present invention.

Detailed Description

The present invention will be described below with reference to specific examples, but the embodiments of the present invention are not limited thereto. The experimental methods in which specific conditions are not specified in examples are generally commercially available under the conventional conditions and the conditions described in the manual, or under the general-purpose equipment, materials, reagents and the like used under the conditions recommended by the manufacturer, unless otherwise specified. The starting materials required in the following examples and comparative examples are all commercially available.

Example 1

A method for preparing a gel capable of stabilizing a fragrance material, comprising the steps of:

step 1, preparing a gelling agent: respectively dissolving racemic malic acid and nicotine in ethanol according to a molar ratio of 2;

step 2, preparation of gel:

dissolving a fragrant substance into 1, 2-propylene glycol to obtain a fragrant substance-containing solvent, wherein the mass volume ratio of the fragrant substance to the 1, 2-propylene glycol is 1g;

weighing a certain amount of 0.91g of the racemic malic acid nicotine salt gelling agent prepared in the step 1, placing the racemic malic acid nicotine salt gelling agent into a test bottle, adding 20mL of the solvent containing the fragrance substances (which indicates that the solvents with different volumes can be fixed when the amount of the gelling agent is fixed, wherein 20mL refers to the highest solvent amount that 0.91g of the gelling agent can be fixed) into the test bottle, dissolving the solvent by heating and stirring or ultrasonic waves, and standing the solution in an ice-water bath at the temperature of 2 ℃ for 2.5 hours to form the fragrance-carrying supramolecular gel.

Racemic malic acid is a non-volatile carboxylic acid and can form the corresponding nicotine salt with nicotine in tobacco itself. Belonging to the hydroxyl-containing polybasic aliphatic carboxylic acid. When the acid-base ratio is 2 ⁺ …H-O ^- ) Heterogeneous synthons (3 in figure 3), and basic structural units formed by the supramolecular synthons are mutually connected through intermolecular alcohol hydroxyl hydrogen bonds (4 in figure 3) to form a 1D hydrogen bond network, and then are mutually wound and interwoven to form a fiber network (SAFINs) through self-assembly, and finally the racemic malic acid nicotine salt gelling agent is formed. The supramolecular structural unit and 1-dimensional hydrogen bond network forming the gelling agent are shown in figure 3Each synthon has been identified in figure 3:1 is a carboxylic acid dimer hydrogen bond homosynthon, 2 is a pyridine nitrogen-carboxylic acid hetero-synthon, and 3 is a pyrrole nitrogen-carboxylic acid charge-assisted hydrogen bond (N) ⁺ …H-O ^- ) Hetero synthon, 4 is an intermolecular alcoholic hydroxyl hydrogen bond.

Example 2

This example provides the use of the flavor-loaded supramolecular gel prepared in example 1 of the invention in heating cigarettes

The nicotine salt supermolecule gel can be applied in the manufacturing process of reconstituted tobacco for heating cigarettes by a paper-making method and reconstituted tobacco for heating cigarettes by a thick pulp method respectively, and can be applied with single gel or mixed gels of different types according to actual application.

Heating reconstituted tobacco for cigarettes by a paper-making method:

the first method is as follows: adding the aroma-carrying supramolecular gel prepared in example 1 into a certain amount of smoke-generating agent (1, 2-propylene glycol, glycerol or a mixture of the two in a certain proportion), wherein the mass ratio of the aroma-carrying supramolecular gel to the smoke-generating agent is 5, heating to 85 ℃, melting the gel into a sol state or a solution, uniformly mixing to prepare a mixed coating liquid containing the molten gel and the smoke-generating agent, and spraying the mixed coating liquid onto a tobacco sheet base prepared by a papermaking method by adopting a spraying process. The reconstituted tobacco to which the mixed coating liquid is applied is cooled to room temperature, and the molten gel is gelatinized and uniformly dispersed in the smoke agent. Removing water in the reconstituted tobacco to a proper water content through one or more times of drying, and then performing shredding and rolling processing.

The preparation process of the mixed coating liquid containing the molten gel and the smoke agent has the following characteristics:

1. another preparation is to heat the flavor-bearing supramolecular gel to a molten state to convert it to a sol state or solution, and then add a heated amount of a smoke generator. In the embodiment, the scheme is not adopted, so that the phenomenon that the fused gel is condensed to form a sol-gel mixture due to insufficient melting caused by cooling after the smoke generating agent is added into the fused gel is avoided, and meanwhile, the energy consumption of two-step heating is also reduced;

2. the mass ratio of the added spice to the added smoke agent in the conventional heating cigarette is generally 1. The gel of example 1, in which the smoke generating agent was fixed, can greatly reduce the amount of smoke generating agent added, and at the same time, since the fragrance material was fixed by the gel, the loss of fragrance material in the subsequent drying and water removal process was reduced, and the amount of fragrance was increased by increasing the gel ratio.

The second method comprises the following steps: the aroma-carrying supramolecular gel prepared in example 1 is heated to 85 ℃ to be melted and converted into a sol state or a solution, and the melted gel is directly sprayed on a tobacco sheet base prepared by papermaking method as a coating liquid by a spraying process according to the smoke quantity required by a final product, the quantity of smoke agent fixed by the gel and the viscosity of the melted gel. And cooling the reconstituted tobacco applied with the coating liquid to room temperature, and enabling the molten gel to generate gelation and be uniformly dispersed on the surface of the reconstituted tobacco. Then, shredding and rolling are carried out.

Heating reconstituted tobacco for cigarettes by a thick pulp method:

the first method is as follows: the application of the above gel is concentrated on the subsequent stages of shaping (casting) and drying. The method specifically comprises the following steps: after the reconstituted tobacco is molded by a thick paste method and dried to remove higher moisture, the gel is heated to 85 ℃ to be melted and converted into a sol state or solution, and the sol state or solution is directly used as a coating liquid and sprayed on the reconstituted tobacco by adopting a spraying process;

or adding the aroma-carrying supramolecular gel prepared in the example 1 into a certain amount of smoke agent (1, 2-propylene glycol, glycerol or a mixture of the two in a certain proportion), wherein the mass ratio of the aroma-carrying supramolecular gel to the smoke agent is 5, heating to 85 ℃, melting the gel into a sol state or a solution, uniformly mixing to prepare a mixed coating liquid containing the molten gel and the smoke agent, and spraying the coating liquid onto the reconstituted tobacco by adopting a spraying process. And cooling the reconstituted tobacco applied with the coating liquid to room temperature, and enabling the molten gel to generate gelation and uniformly disperse on the surface of the reconstituted tobacco or in the smoke agent. Removing water in the reconstituted tobacco to a proper water content through one or more times of drying, and then performing shredding and rolling processing.

Because the moisture content of the reconstituted tobacco leaves by the thick pulp method is higher and the smoke generation amount is not high, the proportion of the additional smoke generation agent is properly increased compared with that of the tobacco leaves by the paper-making method.

The second method comprises the following steps: the aroma-carrying supramolecular gel prepared in example 1 was used as a component of the slurry. The method comprises the following specific steps: mixing tobacco raw materials, adhesive, smoke agent and the like, crushing into powder with a certain mesh number, adding a certain amount of water, adding the fragrance-carrying supermolecule gel prepared in the example 1 at 50-60 ℃, and fully stirring to form uniform slurry. And then uniformly spreading the mixture on a circulating metal belt, heating to 80 ℃ (the temperature of the thick liquid method can be slightly lower than or equal to the gelatinization temperature, because the mixture is heated on one metal belt and is quickly heated), melting the gel in the slurry, then gradually cooling, gelatinizing the molten gel, simultaneously drying, dehydrating and solidifying the slurry in multiple stages, and finally stripping to obtain the reconstituted tobacco.

The reason is as follows: firstly, mixing at 50-60 ℃ is a common temperature condition for pulping, so that the mixing uniformity of the pulp can be ensured; in the subsequent manufacturing process, the slurry mixed with the gel is laid on a metal belt, so that the contact area between the gel and a heating area is increased, the gel can be rapidly and uniformly melted at 80 ℃, the gel can be uniformly distributed in the reconstituted tobacco on one hand, and the loss of flavor substances in the process is reduced on the other hand; and the subsequent gradual cooling ensures that dehydration and gelation are synchronously and uniformly carried out.

Example 3

This example provides the use of the aroma-bearing supramolecular gel prepared in example 1 in electronic cigarettes.

The nicotine salt supramolecular gel can be applied to electronic cigarettes in 2 ways, and can be a single gel or different types of mixed gels according to actual application.

The method comprises the following steps: after drying the flavor-carrying supramolecular gel prepared in the example 1 in a drying oven at a constant temperature of 40 ℃ for 24-36h, grinding the dried gel into uniform microparticles, adding a certain amount of the aerosol into a certain amount of a smoking agent for electronic cigarettes according to a certain proportion, fully stirring, wherein the smoking agent is a mixed solvent of glycerol and 1, 2-propylene glycol 1.5 (volume ratio), the mass ratio of the flavor-carrying supramolecular gel to the smoking agent is 1.

The smoke agent in the electronic cigarette is equivalent to a dispersion medium of gel, the proportion of the smoke agent is not too low, and the addition amount of the gel is reduced as much as possible on the premise of ensuring the fragrance amount and the smoke amount.

The second method comprises the following steps: the gel itself, in which a large amount of 1, 2-propanediol is fixed, is used as the gel-state atomizing material.

Under the condition of the heating temperature of the electronic cigarette, the cigarette liquid containing the gel is subjected to gel melting macroscopically, and gel network disassembly and separation of supramolecular structural units until the supramolecular synthon is broken microscopically, so that the nicotine locked by the gel is released and is released in coordination with the flavor substance and the smoke agent to be inhaled; when smoking is stopped or not used, the melted gel undergoes gelation again due to the thermo-reversible nature of the supramolecular gel, and nicotine and carboxylic acid molecules recombine to form supramolecular synthons, thereby forming supramolecular building blocks which further assemble into a fiber network to immobilize the condensed flavor and smoke producing agents therein.

Example 4

step 1, preparing a gelling agent: respectively dissolving racemic malic acid and nicotine in ethanol according to a molar ratio of 2 to 1, stirring at room temperature until completely dissolving to respectively obtain a racemic malic acid solution and a nicotine solution, then fully mixing the two solutions to obtain a mixed solution, heating the mixed solution to reflux, reacting for more than 30min, performing rotary evaporation, and drying the product obtained by rotary evaporation at 40 ℃ for 1h to obtain a racemic malic acid nicotine salt gelling agent;

step 2, preparation of gel:

dissolving a fragrant substance by using a mixed solvent of 1, 2-propylene glycol and glycerol (1, 2-propylene glycol and glycerol in a volume ratio of 2; and then adding the flavor-containing substance into the racemic nicotine malate salt gelling agent obtained in the step 1, dissolving the solvent by heating and stirring or ultrasonic treatment, and standing in an ice water bath to form gel.

In the step 1, the mass-to-volume ratio of the racemic malic acid to the ethanol is 1g.

And 2, setting the mass-to-volume ratio of the flavor substance to the mixed solvent of 1, 2-propylene glycol and glycerol to be 1g.

Claims

1. A method for preparing a gel capable of stabilizing a fragrant substance, comprising the steps of:

；

step 2, preparation of gel:

dissolving the fragrant substance by using an organic solvent to obtain a fragrant substance-containing solvent; and then adding the flavor-containing substance solvent into the racemic malic acid nicotine salt gelling agent obtained in the step 1, dissolving the mixture by heating and stirring or ultrasonic treatment, and standing the mixture in an ice water bath to form gel.

2. The preparation method according to claim 1, wherein in the step 1, the mass volume ratio of racemic malic acid to ethanol is 1g to 20 to 30mL, the mass volume ratio of nicotine to ethanol is 1g to 100 to 300mL, the rotary evaporation temperature is 50-60 ℃, and the rotary evaporation pressure is 180-200mbar.

3. The preparation method according to claim 1, wherein in step 2, the mass volume ratio of the flavor substance to the organic solvent is 1g to 30mL, the mass volume ratio of the racemic nicotine malate gelling agent to the flavor-containing solvent is 1g to 30mL, the temperature of an ice water bath is 4 ℃, and the standing time in the ice water bath is 1 to 3h.

4. The method of claim 1, wherein the aroma substance is selected from the group consisting of: beta-damascenone, nootkatone, beta-dihydrodamascenone, perillyl alcohol, citronellol, linalool, leaf alcohol, nerol, geraniol, beta-phenylethyl alcohol, citronellal, menthol, benzyl alcohol, solanone, geranylacetone, megastigmatrienone, beta-ionone, citral, safranal, phenylacetaldehyde, methyl hexanoate, ethyl hexanoate, amyl hexanoate, isoamyl hexanoate, ethyl heptanoate, methyl benzoate, ethyl isovalerate, methyl salicylate, isovaleric acid, 3-methylpentanoic acid, alpha-phellandrene, limonene, bisabolene, and ocimenene.

5. The preparation method according to claim 1, wherein the organic solvent is one or more selected from 1, 2-propylene glycol, 1, 3-propylene glycol and glycerol.