A tobacco flavoring, its preparation method and application

Abstract

This invention discloses a tobacco flavoring, its preparation method, and its application, belonging to the field of tobacco processing technology. The flavoring comprises a cigar tobacco extract prepared by hot reflux extraction of cigar tobacco leaves with ethanol, followed by LX-8 macroporous adsorption resin column chromatography and precise collection and concentration of the 90% volume fraction of ethanol eluent. It preferably contains specific modifying components such as coffee extract, methyl ionone, and ethyl maltol, as well as propylene glycol. The key to its preparation method lies in mixing the components under an inert atmosphere, followed by dynamic aging and static aging treatments, with pH stability as the aging endpoint criterion. Applying this flavoring to reconstituted tobacco leaves and cigarettes can specifically enhance the natural tobacco aroma weakened by the tar reduction process, and significantly improve the harmony, purity, and aftertaste comfort of the aroma, effectively solving the technical problem of poor integration between traditional added flavorings and the tobacco matrix.

Description

Technical Field

[0001] This invention belongs to the field of tobacco processing technology, specifically relating to a tobacco flavoring, its preparation method, and its application. Background Technology

[0002] The flavor quality of tobacco products is a key factor determining their sensory experience. This flavor primarily originates from the complex chemical components formed during the cultivation, processing, and curing of tobacco leaves. These components collectively constitute the inherent "natural tobacco aroma." This aroma is not the odor of a single substance, but rather a holistic fragrance characteristic formed by the synergistic effects of pyrazines, furans, ketones, aldehydes, and various acidic components in specific proportions and relationships. For cigarette products, the ability to retain and highlight the inherent "natural tobacco aroma" of their blended tobacco leaves is central to determining their aroma quality, style characteristics, and sensory satisfaction.

[0003] However, in the ongoing process of reducing tar and harm in cigarettes, maintaining the "natural aroma" of tobacco faces an inherent technical contradiction. To reduce the release of tar and other harmful components, current tar reduction technologies are primarily based on two physical principles: filtration and dilution. On the one hand, increasing filter length or using composite filter structures improves the efficiency of trapping particulate matter in the smoke; on the other hand, increasing the permeability of cigarette paper or introducing ventilation into the filter dilutes the mainstream smoke. While these measures effectively achieve tar reduction goals, because their mechanisms of action do not specifically differentiate between harmful substances and aroma components, they often simultaneously reduce a significant amount of volatile and semi-volatile aroma compounds while trapping or diluting tar. The direct consequence is that the natural aroma of tar-reduced cigarettes tends to decrease in intensity, characteristic flavor weakens, and the overall smoke becomes thinner, resulting in a decline in sensory quality.

[0004] When the inherent aroma of tobacco is structurally weakened due to tar reduction processes, the technical focus of conventional added flavorings is not to directly and effectively replenish the inherent aroma, but rather to introduce distinctive and intense exogenous aromas (such as fruit, sweet, or honey notes). This is a substitution or masking strategy, aiming to transfer or cover up the weakened inherent aroma perception with new and prominent aroma impressions. As a result, there is a lack of chemical structural homology and sensory characteristic harmony between the added flavor and the inherent aroma components remaining in the tobacco matrix, making it difficult to achieve deep flavor fusion and synergy. Instead, it easily leads to aroma separation, disordered layers, and even the introduction of discordant characteristics of added flavorings, failing to fundamentally solve the core problem of insufficient inherent aroma.

[0005] Even when some technical solutions attempt to directly supplement the natural aroma by adding tobacco extracts, it is often difficult to achieve an ideal balance between effectively supplementing the aroma intensity and maintaining or even improving the overall harmony of the aroma. This results in the final product still having problems such as insufficient purity of aroma, insufficient richness of layers, or insufficient overall harmony in terms of sensory perception, which restricts its application effect in improving the overall quality of low-tar cigarettes.

[0006] To address the above problems, this invention is proposed. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a tobacco flavoring, its preparation method, and its application. This flavoring is designed to specifically supplement and enhance the inherent aroma of tobacco weakened by the tar reduction process, rather than simply masking it. Simultaneously, through a specific formulation system and controllable preparation process, it solves the problems of rough aroma, insufficient harmony, and poor stability encountered when using existing added flavorings or tobacco extracts. This significantly improves the sensory quality of tar-reduced cigarettes, resulting in a high-quality experience with a mellow and harmonious aroma, rich taste, and clean aftertaste.

[0008] The present invention solves the technical problem by adopting the following technical solution:

[0009] The first aspect of the present invention provides a tobacco flavoring, comprising a cigar tobacco leaf extract, wherein the cigar tobacco leaf extract is prepared by hot reflux extraction of cigar tobacco leaves with ethanol solution, followed by LX-8 macroporous adsorption resin column chromatography, and collecting 90% by volume of the ethanol eluent, and then concentrating the extract.

[0010] Preferably, it also contains coffee extract, methyl ionone, ethyl silicate, ethyl isovalerate, vanillin, lemon oil, lavender oil, ethyl maltol, and propylene glycol.

[0011] Preferably, based on the total weight of the flavoring, it comprises the following components: 40-50 wt% cigar tobacco extract, 0.1-0.6 wt% coffee extract, 0.1-0.3 wt% methyl ionone (10%), 0-0.5 wt% ethyl silicate (10%), 0.2-0.5 wt% ethyl isovalerate (10%), 0.1-0.2 wt% vanillin (10%), 0.1-0.3 wt% lemon oil (10%), 0.2-0.5 wt% lavender oil (10%), 0.3-0.5 wt% ethyl maltol (10%), and 30-50 wt% propylene glycol. Wherein, all components at a concentration of 10% are in propylene glycol as a solvent.

[0012] Preferably, based on the total weight of the flavoring, it comprises the following components: 50 wt% cigar tobacco extract, 0.6 wt% coffee extract, 0.3 wt% methyl ionone (10%), 0.5 wt% ethyl silicate (10%), 0.3 wt% ethyl isovalerate (10%), 0.2 wt% vanillin (10%), 0.3 wt% lemon oil (10%), 0.3 wt% lavender oil (10%), 0.4 wt% ethyl maltol (10%), and 47.1 wt% propylene glycol.

[0013] A second aspect of the present invention provides a method for preparing the tobacco flavoring described in the first aspect, comprising the following steps:

[0014] Step S1: Weigh each component according to the formula;

[0015] Step S2: Under an inert atmosphere, the cigar tobacco extract is first mixed evenly with a portion of propylene glycol, and then the remaining components are added and mixed to obtain an initial mixture.

[0016] Step S3: Maintain the inert atmosphere and perform dynamic aging and static aging treatments on the initial mixture in sequence until a stable endpoint is reached;

[0017] Step S4: Obtain the tobacco flavoring.

[0018] Preferably, the inert atmosphere in step S2 is a nitrogen atmosphere.

[0019] Preferably, in step S3, the temperature of the dynamic ripening treatment is 20-30℃, the treatment time is 5-10 days, and continuous stirring at 10-30 rpm is applied at the same time; the static ripening treatment is carried out at 20-30℃ under light-proof conditions, and its duration is determined by step S4, and shall not exceed 30 days.

[0020] Preferably, the criterion for determining the stable endpoint is: monitoring the pH value of the mixture, and determining that maturation is complete when the daily change is less than 0.02 for three consecutive days.

[0021] Preferably, the cigar tobacco extract is prepared by the following method:

[0022] a) Extract cigar tobacco leaves by hot reflux with an ethanol solution of 80-95% by volume. The ratio of cigar tobacco leaves to ethanol solution is 1g:10-15mL. The water bath temperature is 50℃-60℃. Extract 2-3 times, 1-2h each time. Combine the extracts and concentrate under reduced pressure to obtain the extract.

[0023] b) Dissolve the extract in water and then load it onto an LX-8 macroporous adsorption resin column;

[0024] c) First, wash with water for 8-12 column volumes (BV) to remove impurities, then elute sequentially with 30%, 60% and 90% ethanol aqueous solutions, and collect the 90% ethanol eluent.

[0025] d) The 90% ethanol eluent was concentrated under reduced pressure to obtain the cigar tobacco extract.

[0026] The third aspect of the present invention provides the application of the tobacco flavoring described in any one of the first aspects in tobacco products for enhancing the natural aroma of tobacco.

[0027] The present invention has the following beneficial effects:

[0028] 1. This invention selects cigar tobacco leaves, rich in smoky and roasted sweet aroma compounds, as the raw material. Addressing the technical challenges of the complex raw material system, dispersed target flavor components, and the coexistence of numerous off-flavor substances, this invention employs a specific LX-8 macroporous adsorption resin purification process: firstly, highly polar impurities are effectively removed by water washing; then, gradient elution is performed using 30% and 60% ethanol solutions to separate and eliminate a large number of moderately polar non-target components; finally, 90% ethanol solution is precisely controlled as the key elution solvent. This specific process path can systematically eliminate interference and efficiently and selectively elute and enrich the smoky, roasted, and sweet aroma components that contribute most directly to the tobacco's inherent aroma, thereby obtaining a core base material with distinct aroma characteristics and significantly improved purity.

[0029] 2. This invention aims to solve the core problem of flavor disharmony between added flavorings and the overall aroma released during tobacco combustion by constructing a complete process system based on high-purity cigar tobacco extract, with specific modified ingredients, and combining anaerobic mixing with two-stage controllable maturation. This solution, through precise formulation design and process control, simulates and promotes the complex chemical transformations crucial for flavor formation during the natural maturation of tobacco.

[0030] Specifically, the cigar tobacco extract prepared by elution with 90% ethanol not only provides the core aroma components, but is also a complex reaction system rich in acids, alcohols, esters, and nitrogen-containing heterocycles. The modifying ingredients introduced into the formulation, such as coffee extract and ethyl maltol, not only supplement specific aromas, but their molecular structures, including hydroxyl, carbonyl, and pyrazine nitrogen groups, provide a structural basis for in-depth molecular interactions with the base ingredients.

[0031] To achieve deep integration, the preparation process of this invention provides crucial environmental control: First, mixing under nitrogen protection effectively prevents the oxidative rancidity of unsaturated components, ensuring the activity of the raw materials; subsequently, a two-stage controllable ripening process (dynamic stirring and isothermal settling) constructs a mild, oxygen-free, and homogeneous environment, providing sufficient conditions for the slow transformation within the system, which depends on molecular thermal motion and functional group reactions. During this process, three main types of directional interactions occur:

[0032] Firstly, the alkaline nitrogen-containing heterocycles in coffee extract, lavender oil, and other components in the base material form molecular complexes through ionic bonds, hydrogen bonds, and other interactions, directly regulating the volatility and sensory stimulation of the relevant substances.

[0033] Secondly, the inherent esters, alcohols, and acids in the system undergo slow transesterification and equilibrium shifts with the participation of small molecule esters such as ethyl isovalerate, generating ester substances with new structural characteristics, which play a key role in connecting and blending different aromas.

[0034] Thirdly, trace amounts of reducing sugar derivatives, active carbonyl compounds, amino acids, and amines in the system may undergo early Maillard condensation to generate complex precursor substances that can enhance the richness and fullness of the aroma.

[0035] Through the guided chemical transformation described above, the flavoring system is transformed from a physical mixture into a pre-integrated homogeneous system in which internal components undergo molecular association and reaction. This process substantially alters the chemical state, intermolecular forces, and thermal release characteristics of each component. Sensory evaluation results (Table 2) confirm that when this flavoring is applied to cigarettes, its release kinetics are systematically modulated: the modifier effect of the added flavoring is significantly reduced, while the natural tobacco aroma is enhanced, resulting in a more harmonious overall fragrance. This indicates that the release rhythm (timing and intensity) of the pre-integrated components is better synchronized with the natural aroma substances dynamically generated during tobacco combustion, allowing the added flavor to blend more naturally into the release background of the natural tobacco aroma, achieving a qualitative change from physical addition to chemical fusion.

[0036] 3. The systematic combination of the above-mentioned raw materials and processes ultimately solved the core problem of the abrupt aroma of added flavorings and their incompatibility with the natural aroma of tobacco. As shown in Table 2, cigarette samples using the flavorings of this invention showed consistent and significant improvements in all key indicators, including the prominence of the natural aroma, the harmony of the aroma, the purity of the aroma, and the cleanliness of the aftertaste. The overall scores were far superior to the control samples that used only ordinary extracts, simple mixing, or no controlled aging. This proves that this invention can not only specifically compensate for the intensity of the natural aroma, but also optimize the overall structure of the aroma, improve harmony and comfort, and achieve a qualitative change from exogenous addition to endogenous synergy.

[0037] 4. This invention provides a complete end-to-end process, from source control (high-purity base material) and process control (inert environment and controllable maturation) to endpoint determination (pH stability as the standard). This solution not only pursues sensory enhancement but also fundamentally ensures the physicochemical stability and batch consistency of the product by promoting a more thermodynamically stable fragrance system. It overcomes the shortcomings of traditional fragrances, such as easy deterioration and large quality fluctuations, and has clear value for industrial production and promotion. Detailed Implementation

[0038] The present invention will be further described below through embodiments, but is not limited to these embodiments. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in manuals, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified.

[0039] Example 1

[0040] Step (1): Take 1000g of cigar tobacco leaves and grind them to 20 mesh. Add 12L of 95% ethanol solution (material-to-liquid ratio 1g:12mL) and perform hot reflux extraction in a 55℃ water bath. Extract twice, 1.5 hours each time. Combine the two extracts and concentrate them under reduced pressure using a rotary evaporator at 50℃ and -0.09 MPa to recover the ethanol, yielding approximately 98g of dark brown extract.

[0041] Step (2): Dissolve the above extract in 500 mL of deionized water and filter to remove insoluble matter. Load the filtrate into an LX-8 macroporous adsorption resin column (the resin column bed volume is 2 L, which is about 20 times the mass of the extract) that has been pretreated with ethanol and water.

[0042] Step (3): Elute with deionized water at a flow rate of 1.0 BV / h for 10 column volumes (BV) and discard the water wash. Then elute with 30%, 60%, and 90% ethanol aqueous solutions (volume fraction) for 20 BV each, and collect the eluents respectively.

[0043] Step (4): The 90% ethanol eluent was concentrated under reduced pressure at 50°C until no alcohol odor remained, yielding approximately 16g of a brown paste-like cigar tobacco extract (labeled as extract E1). Preliminary evaluation by a professional smoker indicated that extract E1 exhibited a rich, characteristic cigar smoky and roasted sweet aroma, with a pure fragrance. However, when used alone, it was slightly dull and accompanied by a slight grassy or off-putting odor.

[0044] Gas chromatography-mass spectrometry (GC-MS) analysis of extract E1 revealed that it is rich in various aroma components that significantly contribute to the natural aroma of tobacco, mainly including: nicotine, 2,3-dimethylpyrazine (providing smoky and roasted nutty aromas), 5-hydroxymethylfurfural (providing caramel sweetness), geraniol (providing a sweet floral aroma), and nitrogen-containing heterocyclic compounds such as pyrrolidinylpyridine and 2-acetylpyrrole, which have roasted sweetness characteristics. The aroma characteristics of this extract are dominated by a significant smoky, roasted sweetness, which is highly similar to the natural aroma of cigar tobacco leaves. Aroma component analysis data are shown in Table 1.

[0045] Table 1. Aroma component analysis of 90% ethanol eluent

[0046]

[0047]

[0048]

[0049] Example 2

[0050] This embodiment demonstrates the preferred formulation and complete process.

[0051] Formula: Based on the preparation of 100g of flavoring, accurately weigh the following: 50.0g of cigar tobacco leaf extract (E1) obtained in Example 1, 0.6g of coffee extract (10% solid content), 0.3g of 10% methyl ionone (solvent is propylene glycol), 0.5g of 10% ethyl silicate, 0.3g of 10% ethyl isovalerate, 0.2g of 10% vanillin, 0.3g of 10% lemon oil, 0.3g of 10% lavender oil, 0.4g of 10% ethyl maltol, and 46.7g of propylene glycol (to bring the total weight to 100g).

[0052] The specific preparation method is as follows:

[0053] (1) In a sealed mixing vessel filled with high-purity nitrogen, cigar tobacco extract (E1) and about 15g of propylene glycol are stirred and mixed at 30°C for 15 minutes to form a uniform slurry.

[0054] (2) While maintaining a nitrogen atmosphere, add coffee extract and ethyl maltol in sequence and stir for 10 minutes; then add methyl ionone, ethyl silicate, ethyl isovalerate, vanillin, lemon oil, lavender oil and the remaining propylene glycol, and stir for 40 minutes until completely homogeneous to obtain the initial mixture.

[0055] (3) Transfer the mixture to a maturation reactor with temperature control and low-speed stirring, and stir continuously at 20 rpm for 7 days at 28±1℃ (dynamic maturation).

[0056] (4) Turn off the stirring and let it stand at 28±1℃ in the dark for maturation. Take a sample daily and measure the pH value of the mixture with a pH meter.

[0057] (5) After standing for 20 days, the pH value readings changed by less than 0.01 for three consecutive days, indicating that the stable endpoint had been reached. Discharge the material to obtain the tobacco flavoring product of the present invention (labeled as flavoring S1).

[0058] Example 3

[0059] This embodiment illustrates another specific implementation of the tobacco flavoring of the present invention, as detailed below:

[0060] Formula: To prepare 100g of flavoring, weigh out: 45.0g of cigar tobacco extract (E1), 0.3g of coffee extract, 0.15g of 10% methyl ionone, 0.2g of 10% ethyl silicate, 0.35g of 10% ethyl isovalerate, 0.15g of 10% vanillin, 0.2g of 10% lemon oil, 0.4g of 10% lavender oil, 0.35g of 10% ethyl maltol, and 52.85g of propylene glycol.

[0061] Preparation: Except for adjusting the aging process parameters to dynamic aging (25℃, 10rpm, 8 days) and static aging (25℃, 22 days), the remaining steps were the same as in Example 2. The pH reached stability on the 19th day of static aging, and flavoring S2 was obtained.

[0062] Example 4

[0063] This embodiment illustrates another specific implementation of the tobacco flavoring of the present invention, as detailed below:

[0064] Formula: Same as Example 3.

[0065] Preparation: The mixing steps were the same as in Example 2. The aging process was adjusted as follows: dynamic aging was carried out at 22°C and 30 rpm for 5 days; followed by static aging at 22°C in the dark. After 28 days of static aging (near the maximum limit), the pH value change reached the target, yielding fragrance S3. This example demonstrates that the process remains effective even near the lower limit of the range.

[0066] Comparative Example 1

[0067] According to the formulation of Example 2, flavoring D1 was prepared using only 50g of cigar tobacco extract (E1) and 50g of propylene glycol, without adding any other modifying flavoring ingredients, and following the same mixing and aging process.

[0068] Comparative Example 2

[0069] The 60% ethanol eluent collected in step (3) of Example 1 was concentrated to obtain extract E2. This extract was used to replace E1, and fragrance D2 was prepared entirely according to the formulation and process of Example 2.

[0070] Comparative Example 3

[0071] Weigh all components according to the formulation of Example 2, and simply mechanically stir in air (without nitrogen protection) in a beaker for 1 hour until the appearance is uniform. No aging treatment is performed to obtain flavor D3.

[0072] Comparative Example 4

[0073] The initial mixture was prepared according to the formulation and mixing steps of Example 2 (without nitrogen protection), and then sealed and placed in a light-proof cabinet at 28°C for natural aging for 28 days to obtain fragrance D4.

[0074] Test Example 1

[0075] The flavorings S1-S3 and D1-D4 prepared above were diluted with ethanol to a concentration of 5%, and added at a rate of 0.1% by weight of tobacco shreds. They were then evenly sprayed onto standard flue-cured tobacco shreds of the same batch and formula. The mixture was equilibrated for 48 hours at a temperature of (22±1)℃ and a relative humidity of (60±2)%. The mixture was then rolled into test cigarette samples using conventional rolling parameters and equipped with a filter tip with a filter tip ventilation structure.

[0076] Single-blind tastings were conducted by cigarette tasting experts in a standard tasting room. Scores were given for five key indicators: prominence of the tobacco's natural aroma, harmony of flavor, smoothness (irritation) of the smoke, intensity of off-flavors (impurities), and cleanliness of the aftertaste. Each indicator was scored out of 10 (higher scores indicate better results). The average results are shown in Table 2 below.

[0077] Table 2. Evaluation Results

[0078]

[0079] The sensory evaluation data in Table 2 show that, compared with the blank without added flavoring, the cigarette samples using the flavorings (S1-S3) of this invention all showed improvements in the prominence of the natural tobacco aroma, the harmony of the aroma, the smoothness of the smoke, the purity of the aroma, and the cleanliness of the aftertaste.

[0080] Specific analysis reveals the following: First, the specific formulation combination plays a crucial role in enhancing harmony and purity. Under the same preparation process, flavoring S1, containing a complete modification system including coffee extract and lavender oil, shows significantly improved aroma harmony and purity compared to flavoring D1, which only contains cigar tobacco extract, while maintaining a similar level of aroma prominence. This directly addresses the potential issues of insufficient aroma harmony and thin layers when tobacco extracts are used alone. Second, the specific preparation process of the extracts is fundamental to obtaining a rich aroma. Flavoring D2, prepared using extracts with different elution stages (60% ethanol), exhibits a significantly weaker aroma prominence than S1, which uses a specific 90% ethanol eluent, demonstrating the necessity of this specific enrichment step for effectively supplementing and enhancing the natural aroma of tobacco. Finally, the complete preparation process leads to overall quality optimization. Compared to samples that are simply mixed (D3) or only subjected to conventional static aging (D4), flavoring S1, produced by the inert gas protection and two-stage controllable aging process of this invention, shows superior performance in aroma harmony, smoke smoothness, and clean aftertaste, demonstrating the positive effect of this process on promoting deep flavor integration and enhancing aroma richness and stability.

[0081] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A tobacco flavoring, characterized in that, It contains cigar tobacco leaf extract, which is prepared by hot reflux extraction of cigar tobacco leaves with ethanol solution, followed by LX-8 macroporous adsorption resin column chromatography, collecting 90% volume fraction of ethanol eluent, and then concentrating it.

2. The tobacco flavoring according to claim 1, characterized in that, It also contains coffee extract, methyl ionone, ethyl silicate, ethyl isovalerate, vanillin, lemon oil, lavender oil, ethyl maltol, and propylene glycol.

3. The tobacco flavoring according to claim 1, characterized in that, Based on the total weight of the flavoring, it comprises the following components: 40-50 wt% cigar tobacco extract, 0.1-0.6 wt% coffee extract, 0.1-0.3 wt% methyl ionone (10%), 0-0.5 wt% ethyl silicate (10%), 0.2-0.5 wt% ethyl isovalerate (10%), 0.1-0.2 wt% vanillin (10%), 0.1-0.3 wt% lemon oil (10%), 0.2-0.5 wt% lavender oil (10%), 0.3-0.5 wt% ethyl maltol (10%), and 30-50 wt% propylene glycol.

4. The tobacco flavoring according to claim 3, characterized in that, Based on the total weight of the flavoring, it comprises the following components: 50 wt% cigar tobacco extract, 0.6 wt% coffee extract, 0.3 wt% methyl ionone (10%), 0.5 wt% ethyl silicate (10%), 0.3 wt% ethyl isovalerate (10%), 0.2 wt% vanillin (10%), 0.3 wt% lemon oil (10%), 0.3 wt% lavender oil (10%), 0.4 wt% ethyl maltol (10%), and 47.1 wt% propylene glycol.

5. A method for preparing the tobacco flavoring as described in any one of claims 1-4, characterized in that, Includes the following steps: Step S1: Weigh each component according to the formula; Step S2: Under an inert atmosphere, the cigar tobacco extract is first mixed evenly with a portion of propylene glycol, and then the remaining components are added and mixed to obtain an initial mixture. Step S3: Maintain the inert atmosphere and perform dynamic aging and static aging treatments on the initial mixture in sequence until a stable endpoint is reached; Step S4: Obtain the tobacco flavoring.

6. The method according to claim 5, characterized in that, The inert atmosphere mentioned in step S2 is a nitrogen atmosphere.

7. The method according to claim 5, characterized in that, In step S3, the temperature of the dynamic ripening treatment is 20-30℃, the treatment time is 5-10 days, and continuous stirring at 10-30 rpm is applied at the same time; the static ripening treatment is carried out at 20-30℃ under light-proof conditions, and its duration is determined by step S4, and shall not exceed 30 days.

8. The method according to claims 5-7, characterized in that, The criterion for determining the stable endpoint is: monitoring the pH value of the mixture, and determining that maturation is complete when the daily change is less than 0.02 for three consecutive days.

9. The method according to any one of claims 5, characterized in that, The cigar tobacco leaf extract was prepared by the following method: a) Extract cigar tobacco leaves by hot reflux with an ethanol solution of 80-95% by volume. The ratio of cigar tobacco leaves to ethanol solution is 1g:10-15mL. The water bath temperature is 50℃-60℃. Extract 2-3 times, 1-2h each time. Combine the extracts and concentrate under reduced pressure to obtain the extract. b) Dissolve the extract in water and then load it onto an LX-8 macroporous adsorption resin column; c) First, wash with water for 8-12 column volumes to remove impurities, then elute successively with 30%, 60% and 90% ethanol aqueous solutions, and collect the 90% ethanol eluent. d) The 90% ethanol eluent was concentrated under reduced pressure to obtain the cigar tobacco extract.

10. The use of any one of claims 1-4 in tobacco products to enhance the natural aroma of tobacco.

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