Auxiliary curing method for air-cured tobacco leaves

Abstract

The invention discloses an auxiliary curing method for cured tobacco leaves, and relates to the technical field of tobacco leaf curing processing, and the method comprises the following steps: during curing of the cured tobacco leaves, when the water content of the tobacco leaves is higher than 40%, introducing at least one oxidizing gas including ozone, oxygen or hydrogen peroxide; the oxidizing gas is introduced into the air-drying room at 10 a.m. and 16 p.m. every day through ventilation pipelines arranged between two layers of tobacco leaves on the two sides of the length direction of the air-drying room, and the ventilation time is 25-30 min every time. According to the method, the appearance quality of the air-cured tobacco leaves is guaranteed, oxidative degradation of macromolecular substances such as protein, chlorophyll and carotenoid of the air-cured tobacco leaves and formation of aroma small molecular substances are promoted, and the mildew rate of the tobacco leaves in the air-curing process is effectively reduced; the green smell and bitter taste caused by insufficient curing maturity of the air-cured tobacco leaves are eliminated to a great extent, and the sensory evaluation quality of the air-cured tobacco leaves is improved.

Description

Technical Field

[0001] This invention relates to the field of tobacco leaf drying and processing technology, and in particular to an auxiliary conditioning method for dried tobacco leaves. Background Technology

[0002] The curing process of sun-dried tobacco leaves is a crucial step in transforming fresh tobacco leaves into industrially usable raw materials through a series of complex physiological and biochemical reactions under natural or artificially controlled environments. This process involves the directed degradation of macromolecules within tobacco leaf cells, such as starch, protein, chlorophyll, and carotenoids, under the action of enzymes, converting them into smaller sugars, amino acids, and various aroma compounds. However, in actual production, this transformation process is often incomplete and uneven, with a long processing cycle. Microorganisms in the environment easily proliferate on the tobacco leaves, leading to frequent occurrences of discolored leaves (green or yellow) and mold. Green and yellow leaves typically exhibit a raw, bitter taste, accompanied by a burnt and woody aroma; while moldy leaves show a sharp decrease in aroma and a pronounced musty smell. These problems not only severely damage the appearance and sensory evaluation quality of the tobacco leaves but also pose a continuous challenge to subsequent formulation and product stability.

[0003] To address the aforementioned problems, existing technologies have implemented corresponding technical measures for prevention and control, such as biological additives, which involve introducing exogenous microorganisms or enzyme preparations during the preparation process. For example, patent application number CN202211515480.6 discloses a method for accelerating the oxidation of starch and protein in tobacco leaves by adding exogenous microorganisms; patent application number CN202311393885.1 discloses a method for accelerating the degradation of tobacco leaf cell wall substances by adding microorganisms or enzyme aids; and patent application number CN202211133328.1 discloses a strain of bacteria that can be sprayed on the surface of tobacco leaves to prevent mold growth. While these methods are theoretically feasible, their limitations are significant: their mechanisms of action are highly specific, with a single strain or enzyme often targeting only a specific type of substrate. Furthermore, the synergistic degradation of tobacco leaf components requires a complex enzyme system, resulting in limited effectiveness of single formulations and high costs, complex processes, and difficulty in controlling stability when multiple formulations are combined. More importantly, the process of its action is poorly controllable. The life activities of microorganisms are greatly affected by environmental temperature and humidity, which can easily lead to insufficient or excessive regulation, thus introducing new uncertainties and even producing adverse byproducts.

[0004] Existing technologies for the auxiliary regulation of the internal chemical components of sun-dried tobacco leaves are mostly concentrated in the tobacco fermentation stage. They are aimed at improving the internal chemical components of tobacco leaves after the drying quality has been determined. However, the improvement effect is not good. There is a lack of a universal method that can be effective in the early stage of tobacco curing, when the cells are still active and the water content is high, and can act simultaneously, synergistically and controllably on multiple internal component transformation pathways and inhibit microbial growth. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides an auxiliary conditioning method for sun-dried tobacco leaves. During the sun-drying and conditioning process of tobacco leaves, at a specific window period when the moisture content of the tobacco leaves is higher than 40%, a low-concentration, intermittent oxidizing gas treatment is used to intervene in the transformation process of the tobacco leaf contents and the microbial activity on the surface of the tobacco leaves in advance, so as to promote the oxidative degradation of the macromolecular substances in the tobacco leaves, inhibit the mold growth of the tobacco leaves, and improve the sensory quality of the tobacco leaves.

[0006] The present invention provides a method for assisting in the conditioning of sun-dried tobacco leaves, comprising: During the curing of tobacco leaves in the drying room, the moisture content of the tobacco leaves is monitored in real time. When the tobacco leaves are before the color-fixing period and their moisture content is higher than 40%, oxidation control is initiated. The target concentration range of the oxidizing gas is set to 0.5–1.0 ppm, and the oxidizing gas is introduced at multiple intervals per day. The oxidizing gas is introduced into the drying room at predetermined intervals each day to bring the concentration of the oxidizing gas to the target concentration range and maintain it for 30 minutes. The moisture content of the tobacco leaves is continuously monitored. When the moisture content of the tobacco leaves drops below 40%, the oxidation control is terminated.

[0007] Furthermore, the oxidizing gas includes at least one of ozone, oxygen, or hydrogen peroxide.

[0008] Furthermore, the oxidizing gas is introduced twice a day, with each introduction lasting 25 to 30 minutes.

[0009] Furthermore, the oxidizing gas is introduced into the drying room at 10:00 AM and 4:00 PM every day.

[0010] Furthermore, the stage before the tobacco leaves reach the color-fixing period and when their moisture content is higher than 40% includes the wilting period, the yellowing period, and the browning period.

[0011] Furthermore, the oxidizing gas is blown into the drying room through ventilation ducts.

[0012] Furthermore, the diameter of the ventilation duct is 39-41 mm, and multiple ventilation holes with a diameter of 1.5-2.5 mm are opened on its wall along the axial direction at intervals of 490-510 mm.

[0013] Furthermore, the ventilation ducts are laid on both sides of the drying room along its length, and are located in the middle of every two layers of tobacco leaves.

[0014] The present invention also provides the application of a method for assisting in the preparation of sun-dried tobacco leaves according to any one of the above claims in the preparation of cigar tobacco products.

[0015] The present invention also provides a cigar tobacco product, which is prepared by a method for assisting in the conditioning of sun-dried tobacco leaves as described in any of the above claims.

[0016] The present invention provides an auxiliary method for conditioning sun-dried tobacco leaves, which has the following beneficial effects: (1) When the moisture content of tobacco leaves is higher than 40% during the curing process, oxidizing gas is introduced. The moisture in the tobacco leaves provides a medium for the reaction between the oxidizing gas and the substances in the tobacco leaves, increases the reaction interface, improves the reaction rate between the oxidizing gas and each substance, and also makes the tobacco leaves react evenly, avoiding the differences in appearance quality, sensory evaluation characteristics and other aspects of tobacco leaves due to uneven reaction. (2) Oxidizing gas is introduced twice a day. After multiple introductions of oxidizing gas, the substances in the tobacco leaves react completely, promoting the oxidative decomposition of macromolecules such as proteins, starches, chlorophyll, and carotenoids in the tobacco leaves. It also promotes the formation of small molecule aroma substances such as amino acids, monosaccharides and disaccharides, phenols, and cyperidines, promoting the uniform change of tobacco leaf color and improving the sensory evaluation of aroma and aroma quantity. It reduces the bitterness produced by the combustion of proteins, the green smell produced by the combustion of chlorophyll, and the woody smell produced by the combustion of lignin, which are not conducive to improving the quality of cigar tobacco leaves. At the same time, the tobacco leaves are in an oxidizing gas environment for a long time, which deteriorates the living environment of moldy microorganisms and effectively controls the mold rate of tobacco leaves. (3) The tobacco leaves treated by the sun-dried tobacco leaf auxiliary conditioning method of the present invention have significantly improved appearance quality, significantly reduced green and yellow content, and significantly improved uniformity of appearance color; the sensory evaluation quality is significantly improved, and the bitterness, raw green smell, woody smell and other impurities are significantly reduced or even eliminated, and the aroma is more abundant and the flavor is richer. It effectively solves the problems of low homogenization during tobacco leaf conditioning, poor appearance and sensory quality after conditioning, and high rate of mold growth in tobacco leaves. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating an auxiliary conditioning method for sun-dried tobacco leaves provided in one embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should be understood that although the terms first, second, third, etc., may be used to describe the acquisition modules in the embodiments of the present invention, these acquisition modules should not be limited to these terms. These terms are only used to distinguish the acquisition modules from each other.

[0021] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0022] It should be noted that the directional terms such as "upper," "lower," "left," and "right" used in the embodiments of the present invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. Furthermore, in the context, it should be understood that when it is mentioned that an element is formed "upper" or "lower" of another element, it can not only be formed directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element.

[0023] This invention is based on the physiological and biochemical changes during tobacco curing and applies oxidizing gases to a key early stage of tobacco curing. Its core principles include: Water as a medium: When the moisture content of tobacco leaves is higher than 40%, the tobacco leaves cells still maintain high physiological activity and have sufficient free water content. At this time, when oxidizing gases are introduced, they can dissolve in water to form active substances such as hydroxyl radicals and superoxide anions. These active substances have stronger oxidizing power. Water acts as a carrier to transport the dissolved oxidizing substances to all parts of the tobacco leaf tissue, including mesophyll cells, intercellular spaces, and even the interior of cells. The presence of water increases the reaction interface, that is, it increases the contact area between the oxidizing gas and the contents of the tobacco leaf, transforming the original gas-solid reaction into a more efficient gas-liquid-solid multiphase reaction, increasing the reaction rate of the oxidizing gas with each substance, and also making the reaction more uniform in all parts of the tobacco leaf. Selective regulation of oxidative degradation: The present invention employs an intermittent oxidative process with a target concentration range of 0.5–1.0 ppm to achieve selective oxidation of the components within tobacco leaves. Under low-concentration oxidation conditions, macromolecules such as proteins, chlorophyll, and carotenoids, which have relatively loose structures and numerous reaction sites, preferentially undergo oxidative degradation. Small-molecule aroma compounds such as sugars, amino acids, and phenols, which have already formed, are not easily over-oxidized due to their stable structures. The intermittent oxidative treatment allows for a dynamic balance between oxidation and reduction within the tobacco leaves, preventing cell damage caused by excessive oxidation. Microbial inhibition: Oxidizing gases can oxidize lipids and proteins in the cell walls or cell membranes of microorganisms, causing the cell walls or cell membranes to rupture and cell contents to leak out, thereby rendering the microorganisms inactive; Oxidizing gases can inactivate key enzyme systems of microorganisms, especially sulfur-containing enzymes, thereby disrupting the metabolism of microorganisms. Thus, in an oxidizing environment, the living environment of moldy microorganisms deteriorates, and the mold rate of tobacco leaves can be effectively controlled. refer to Figure 1 The present invention provides an auxiliary conditioning method for sun-dried tobacco leaves, comprising: Step S101: During the curing of tobacco leaves in the drying room, the moisture content of the tobacco leaves is monitored in real time. When the tobacco leaves are before the color-fixing period and their moisture content is higher than 40%, oxidation regulation is initiated. The stages in which the tobacco leaf moisture content is higher than 40% include the wilting stage, the yellowing stage, and the browning stage before the color-fixing stage in the drying cycle. During the wilting stage, the tobacco leaves begin to lose water, the leaves soften, the main veins can still bend and remain intact, and the leaf color changes from bright green to dark green. During the yellowing stage, chlorophyll begins to degrade, and the tobacco leaves start to turn yellow from the leaf tips and edges, with the yellow area gradually expanding. During the browning stage, polyphenols are oxidized, and brown spots or stripes appear on the tobacco leaves, gradually spreading to the entire leaf. During the color-fixing stage, the color of the tobacco leaves is basically fixed, the moisture content drops below 30%, the cells are basically dead, and the physiological and biochemical reactions are significantly slowed down. Therefore, when the moisture content of tobacco leaves is above 40% before the color-fixing period, the tobacco leaf cells still maintain high physiological activity and sufficient intracellular water. At this time, the activation of oxidation regulation provides the necessary liquid reaction medium for the dissolution and penetration of oxidizing gases into the tobacco leaf tissue. Water, as a carrier, greatly increases the contact area and reaction rate between oxidizing gases and macromolecules such as proteins, starches, and chlorophyll inside the tobacco leaf, ensuring the depth and uniformity of the oxidation reaction. This fundamentally avoids the problem of uneven green and yellow patches on the appearance of tobacco leaves caused by uneven reactions.

[0024] Step S102: Set the target concentration range of the oxidizing gas to 0.5 to 1.0 ppm, and set the oxidizing gas to be introduced at multiple intervals per day; Specifically, the oxidizing gas includes at least one of ozone, oxygen, or hydrogen peroxide. The oxidizing gas is introduced into the drying room through ventilation ducts at multiple intervals. Preferably, the oxidizing gas is introduced twice a day to achieve a target concentration of 0.5 to 1.0 ppm and maintain it for 30 minutes.

[0025] Step S103: The oxidizing gas is introduced into the drying room at predetermined intervals every day to make the concentration of the oxidizing gas reach the target concentration range and maintain it for 30 minutes. The moisture content of the tobacco leaves is continuously monitored. When the moisture content of the tobacco leaves drops below 40%, the oxidation regulation is terminated. Preferably, oxidizing gas is introduced twice daily, at approximately 10:00 AM and 4:00 PM, for 25-30 minutes each time. This arrangement, choosing times with suitable temperature and good air circulation, allows sufficient reaction time for the substances within the tobacco leaves. This ensures complete reaction of the substances, promoting the oxidative decomposition of macromolecules such as proteins, starches, chlorophyll, and carotenoids, and the formation of small-molecule aroma compounds such as amino acids, monosaccharides, disaccharides, phenols, and purines. This also promotes a more uniform color change in the tobacco leaves, enhances sensory evaluation of aroma, increases aroma intensity, and reduces [the risk of spoilage]. The process eliminates off-flavors that negatively impact the smoking quality of cigar tobacco, such as bitterness from the combustion of proteins, green odor from the combustion of chlorophyll, and woody odor from the combustion of lignin. When oxidizing gases are introduced, the average concentration of these gases in the drying environment is maintained at 0.5–1.0 ppm for 30 minutes. Maintaining the concentration within this safe range of 0.5–1.0 ppm for 30 minutes is crucial for achieving a balance between effectiveness and safety. Within this concentration range, the oxidative degradation of macromolecules is efficiently triggered, while significantly inhibiting the activity of moldy microorganisms without damaging the cellular structure of the tobacco leaves. This achieves the precise control target of inhibiting bacteria and improving quality without harming the leaves.

[0026] Ventilation ducts for introducing oxidizing gases are installed on both sides of the drying room along its length, located in the middle of every two layers of tobacco leaves. The diameter of the ventilation duct is 39-41 mm, and multiple ventilation holes with a diameter of 1.5-2.5 mm are opened on its axial wall at intervals of 490-510 mm. Preferably, the diameter of the ventilation duct is 40 mm, and multiple ventilation holes with an opening diameter of 2 mm are opened on its axial wall at intervals of 500 mm. This forms a uniform gas distribution network. The combination of small diameter and large spacing ventilation holes allows the gas to escape in a gentle and dispersed manner, forming a uniform air curtain. The 2 mm orifice diameter can generate a fine jet with an appropriate flow rate, which not only ensures the effective range of the gas, but also avoids the high-speed airflow directly impacting the tobacco leaves. The ventilation ducts are installed in the middle of each layer of tobacco leaves, which ensures that the oxidizing gas can completely coat each tobacco leaf, creating a highly uniform reaction environment and ensuring that the overall conditioning of the tobacco leaves is uniform and the quality is consistent.

[0027] The moisture content of tobacco leaves is continuously monitored, and oxidation regulation is terminated when the moisture content of tobacco leaves drops below 40%.

[0028] Example 1: In the cigar tobacco drying workshop in Ede Village, Mosha Town, Xinping County, Yuxi City, the Yunxue 39 cigar core variety was selected for the experiment. The lower tobacco leaves with uniform growth and moderate maturity were selected from the field and divided into two groups after harvesting: Group 1, which was treated with ozone using the modulation method provided by this invention, and the control group using the conventional drying method.

[0029] Treatment Group 1: The drying room is equipped with ventilation ducts with a diameter of 40mm, an opening spacing of 500mm, and an opening diameter of 2mm along its length. During the drying process, when the average moisture content of the tobacco leaves enters the 50%–45% range (the wilting stage), oxidation control is activated. Ozone is introduced at preset times at 10:00 AM and 4:00 PM daily. By adjusting the ozone generator power and duct valves, the ozone concentration at the monitoring point in the middle of the drying room is maintained at 0.5±0.05ppm within 5 minutes and then automatically stopped after 30 minutes. This treatment continues until the average moisture content of the tobacco leaves drops below 40%.

[0030] Control group 1: Except for not using the modulation method provided by this invention to introduce ozone, all parameters and conditions, such as tobacco leaf hanging density and temperature and humidity management in the drying room, were the same as those in treatment group 1.

[0031] Table 1 Comparison of Appearance Quality in Example 1 Referring to Table 1, after the tobacco leaves were dried, an investigation and analysis of the appearance quality of the tobacco leaves showed that, compared with conventional drying treatment, the proportion of green tobacco leaves in the lower part of the Yunxue 39 citrus core variety treated with ozone decreased from 8% to 3%; the proportion of yellow tobacco leaves decreased from 10% to 4%, demonstrating the excellent effect of this invention in promoting uniform and synchronous color transformation of tobacco leaves; the proportion of moldy tobacco leaves decreased from 8% to 2%, verifying the significant inhibitory and killing effect of low-concentration ozone on moldy microorganisms; sensory evaluation results showed that, compared with conventional drying treatment, the woody and green aroma of the lower part of the Yunxue 39 citrus core variety treated with ozone was significantly reduced, the aroma richness was enhanced, and the sweetness was significantly increased, indicating that this invention effectively promoted the degradation of chlorophyll, protein, and lignin, and promoted the generation and accumulation of sugars and various small-molecule aroma substances.

[0032] This embodiment fully demonstrates that, during the withering to browning stage of the lower tobacco leaves of Yunxue 39, when the moisture content is higher than 40%, the method of the present invention, which uses 0.5 ppm ozone and treats twice daily, can effectively regulate the physiological and biochemical processes of tobacco leaves, promote uniform color change, and significantly reduce the rate of green and yellow leaves; create an environment unfavorable to the survival of microorganisms, significantly inhibiting mold growth; deeply oxidize and degrade macromolecules such as starch and protein, and simultaneously promote sugar accumulation and the formation and retention of various small-molecule aroma substances, eliminating impurities from the source, enhancing aroma quantity and flavor, and especially highlighting the sweetness characteristics of the lower tobacco leaves, providing a reliable and efficient process path for improving the quality of lower tobacco leaf processing.

[0033] Example 2: In the cigar tobacco drying workshop of Ede Village, Mosha Town, Xinping County, Yuxi City, the Yunxue 39 cigar filler variety was selected for the experiment. Upper tobacco leaves with uniform growth and moderate maturity were chosen from the field. Upper tobacco leaves are generally thicker, richer in internal substances, and more resistant to processing. In this embodiment, the ozone concentration was moderately increased to 1.0 ppm to verify whether it could more effectively promote the full conversion of the internal substances in the upper tobacco leaves and to explore the concentration adaptability of the method of this invention. After harvesting, the leaves were divided into four groups: treatment groups 2, 3, and 4, which were treated with ozone using the modulation method provided by this invention, and control group 2, which used the conventional drying method.

[0034] Treatment Group 2: The drying room is equipped with ventilation ducts with a diameter of 40mm, an opening spacing of 500mm, and an opening diameter of 2mm along its length. During the drying process, when the average moisture content of the tobacco leaves enters the 50%–45% range (the wilting stage), oxidation control is activated. Ozone is introduced at preset times at 10:00 AM and 4:00 PM daily. By adjusting the ozone generator power and duct valves, the ozone concentration at the monitoring point in the middle of the drying room is maintained at 0.5±0.05ppm within 5 minutes and then automatically stopped after 30 minutes. This treatment continues until the average moisture content of the tobacco leaves drops below 40%.

[0035] Treatment Group 3: The ozone concentration at the monitoring point in the middle of the drying room was made to reach and stabilize at 0.8±0.05ppm within 5 minutes. Other parameters and treatment methods were the same as those in Treatment Group 2.

[0036] Treatment Group 4: The ozone concentration at the monitoring point in the middle of the drying room was made to reach and stabilize at 1.0±0.05ppm within 5 minutes. Other parameters and treatment methods were the same as those in Treatment Group 2.

[0037] Control group 2: Except for not using the modulation method provided by this invention to introduce ozone, all parameters and conditions, such as tobacco leaf hanging density and temperature and humidity management in the drying room, were the same as those in treatment group 2.

[0038] Table 2 Comparison of Appearance Quality in Example 2 Referring to Table 2, after the tobacco leaves were air-dried, the appearance quality of the tobacco leaves was investigated and analyzed. Compared with conventional air-drying, the appearance quality and mold control of the upper tobacco leaves of the Yunxue 39 variety treated with ozone were significantly better than those of the control group. Furthermore, as the ozone concentration increased from 0.5 ppm to 1.0 ppm, the proportion of green tobacco, yellow tobacco leaves, and moldy tobacco leaves gradually decreased. Sensory evaluation results showed that compared with conventional air-drying, the bitterness and irritation of the upper tobacco leaves of the Yunxue 39 variety treated with ozone were significantly reduced in groups 2, 3, and 4, while the aroma was significantly increased, with more pronounced bean and nutty aromas. This demonstrates the efficient conversion ability of this invention for the richer carotenoids and nitrogenous compounds in the upper tobacco leaves. This embodiment demonstrates that the method of the present invention has good concentration adaptability and adjustability. For upper tobacco leaves with rich contents and dense structure, appropriately increasing the ozone concentration from 0.5 ppm to 0.8-1.0 ppm can provide stronger oxidative driving force, further promoting the degradation and transformation of macromolecules such as carotenoids, thereby more effectively eliminating bitterness and off-flavors, and more significantly stimulating high-quality aromas such as bean and nut aromas. In practical applications, the core concentration range of 0.5-1.0 ppm can be optimized according to the tobacco leaf part, thickness, and variety characteristics. Lower concentrations, such as 0.5-0.7 ppm, can be used for lower leaves or thinner leaves, while higher concentrations, such as 0.8-1.0 ppm, can be used for upper leaves or thicker leaves, thereby achieving precise and balanced improvement in the quality of the entire tobacco plant.

[0039] This invention provides an auxiliary processing method for sun-dried tobacco leaves. During the critical window period from the withering stage to the browning stage when the tobacco leaf moisture content is above 40%, a low concentration of oxidizing gas is precisely introduced. Utilizing the tobacco leaf's own moisture as a reaction medium, this method achieves gentle, uniform, and efficient in vivo oxidation. It significantly promotes the oxidative degradation of macromolecules such as proteins, starches, and chlorophyll, resulting in a marked improvement in the appearance quality of the treated tobacco leaves. The greenness and yellowness of the leaves are significantly reduced, and the uniformity of the color is significantly improved. Sensory evaluation shows a significant improvement in smoking quality, with a marked reduction or even elimination of off-flavors such as bitterness, raw greenness, and woody notes. Simultaneously, it drives the accumulation of sugars and the conversion of carotenoids into small-molecule aroma compounds, enriching the aroma with premium notes such as bean and nutty flavors, and increasing the aroma quantity and smoothness. Furthermore, the oxidative environment continuously inhibits the activity of microorganisms such as mold, significantly reducing the mold rate by more than 50%. Ultimately, the processed tobacco leaves have a uniform color, a significantly reduced proportion of green and yellow leaves, and a comprehensive improvement in sensory evaluation quality. Furthermore, the process parameters are highly controllable and applicable to tobacco leaves from different parts and varieties, effectively solving the core technical challenges of poor homogenization, high mold rate, and insufficient internal chemical transformation in the traditional processing method.

[0040] The above description is merely a preferred embodiment of the present invention. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to the specific combination of the above-described technical features, but should also cover other technical solutions formed by any combination of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A method for assisting in the conditioning of sun-dried tobacco leaves, characterized in that, include: During the curing of tobacco leaves in the drying room, the moisture content of the tobacco leaves is monitored in real time. When the tobacco leaves are before the color-fixing period and their moisture content is higher than 40%, oxidation control is initiated. The target concentration range of the oxidizing gas is set to 0.5–1.0 ppm, and the oxidizing gas is introduced at multiple intervals per day. The oxidizing gas is introduced into the drying room at predetermined intervals each day to bring the concentration of the oxidizing gas to the target concentration range and maintain it for 30 minutes. The moisture content of the tobacco leaves is continuously monitored. When the moisture content of the tobacco leaves drops below 40%, the oxidation control is terminated.

2. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 1, characterized in that, The oxidizing gas includes at least one of ozone, oxygen, or hydrogen peroxide.

3. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 1, characterized in that, The oxidizing gas is introduced twice a day, each time for 25 to 30 minutes.

4. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 1, characterized in that, The oxidizing gas is introduced into the drying room at 10:00 AM and 4:00 PM every day.

5. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 1, characterized in that, The stage in which the tobacco leaves are before the color-fixing period and their moisture content is higher than 40% includes the wilting period, the yellowing period, and the browning period.

6. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 1, characterized in that, The oxidizing gas is introduced into the drying room through ventilation ducts.

7. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 6, characterized in that, The ventilation duct has a pipe diameter of 39-41 mm, and its pipe wall has multiple ventilation holes with an opening diameter of 1.5-2.5 mm at an axial spacing of 490-510 mm.

8. The method for assisting in the conditioning of sun-dried tobacco leaves according to claim 7, characterized in that, The ventilation ducts are laid on both sides of the length of the drying room and are located in the middle of every two layers of tobacco leaves.

9. The application of a method for assisting in the preparation of sun-dried tobacco leaves according to any one of claims 1-8 in the preparation of cigar tobacco products.

10. A cigar tobacco product, characterized in that, It is prepared by an auxiliary conditioning method for sun-dried tobacco leaves as described in any one of claims 1-8.

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