A method for improving the stability of sand production in tobacco leaves

Abstract

The application discloses a sand smoke tobacco conditioning method for improving sand stability, which comprises the following steps: a thinning and airing stage; a conditioning preparation stage; an enzymatic conversion stage: controlling the rotation of a fan, increasing the dry ball temperature to a first target dry ball temperature at a preset first temperature rising speed and a first preset temperature gradient between different temperature monitoring points, controlling the wet ball temperature at a first target wet ball temperature, then decreasing the dry ball temperature to a second target dry ball temperature, controlling the wet ball temperature at a second target wet ball temperature after condensation appears on the surface of the tobacco leaves, maintaining the dry ball temperature and the wet ball temperature until the tobacco leaf surface softens and maintaining for a second preset time period; a pigment deposition stage; a color fixing stage; a dry sheet stage; and a temperature decreasing and moisture regaining stage. The application improves the sand rate and sand stability.

Description

Technical Field

[0001] This application relates to the field of tobacco curing and conditioning technology, and more specifically, to a method for conditioning vermilion tobacco leaves to improve the stability of vermilion extrusion. Background Technology

[0002] Vermilion tobacco is a new variety of flue-cured tobacco, attracting much attention for its unique "sweet and glutinous" aroma. The formation of vermilion tobacco is primarily due to the high expression of the CYP82E4 gene, which converts nicotine into nornicotine. This nornicotine, catalyzed by peroxidase and polyphenol oxidase, combines with anthraquinones and other substances to form color-developing compounds. Simultaneously, nornicotine also combines with sugars to form unique aroma precursors. These processes play a crucial role in shaping the distinctive flavor of vermilion tobacco and represent its intrinsic mechanism that distinguishes it from traditional flue-cured tobacco.

[0003] Studies have found that the expression of the CYP82E4 gene and the activities of nicotine demethylase, peroxidase, and polyphenol oxidase in cinnabar tobacco leaves differ significantly under different temperatures and humidity levels. Suitable temperature and humidity are conducive to the accumulation and transformation of various substances during the curing process of cinnabar tobacco leaves. Meanwhile, the sand-producing characteristics of cinnabar tobacco leaves vary with the tiered progression of different reaction processes, most notably in the significant differences in the appearance of the sand-producing rate.

[0004] Traditional modulation methods are mainly based on practical experience, predicting the modulation effect based on appearance, without considering the actual reaction process and activation energy. This leads to uncontrollable effects at each stage of the modulation process, resulting in poor sand extraction stability and low sand extraction rate of cinnabar tobacco leaves. Summary of the Invention

[0005] This application provides a method for conditioning cinnabar tobacco leaves to improve nicotine extraction stability. By pre-conditioning and softening the tobacco leaves before conditioning, the internal substances are pre-converted. Through reasonable conditioning spatial distribution and temperature gradient control, the nicotine extraction stability is improved. Furthermore, during the enzymatic conversion stage, the rate of moisture loss from the tobacco leaf surface is controlled by first raising the temperature and then lowering it. Utilizing the principle of condensation in saturated humid air, the tobacco leaves are forced to prevent excessive moisture loss during conditioning, ensuring that the nicotine inverting enzyme remains in a highly active state. This is beneficial for reducing nicotine production and helps to improve the nicotine extraction rate.

[0006] This application provides a method for preparing cinnabar tobacco leaves to improve the stability of cinnabar output, including:

[0007] Spreading and drying: After harvesting the appropriate or mature cinnabar tobacco leaves, spread them out thinly at room temperature and dry them for the first preset time period;

[0008] Preparation for curing: In the curing barn, hang the tobacco leaves on the hangers at a preset spacing and a preset leaf spacing to avoid overlapping; and set up multiple temperature and humidity monitoring points at preset monitoring intervals in the three-dimensional space of the curing barn.

[0009] Enzymatic conversion stage: Control the fan rotation to raise the dry-bulb temperature to the first target dry-bulb temperature at a preset first heating rate and a first preset temperature gradient between different temperature monitoring points, and control the wet-bulb temperature at the first target wet-bulb temperature. Then, lower the dry-bulb temperature to the second target dry-bulb temperature. After condensation appears on the surface of the tobacco leaves, control the wet-bulb temperature at the second target wet-bulb temperature, maintain the dry-bulb and wet-bulb temperatures until the leaf surface softens, and continue for a second preset time period; wherein the second target wet-bulb temperature is lower than the first target wet-bulb temperature.

[0010] Pigment deposition stage: Control the fan rotation to raise the dry bulb temperature to the third target dry bulb temperature at a preset second heating rate and a second preset temperature gradient between different temperature monitoring points, and control the wet bulb temperature at the third target wet bulb temperature, maintaining the dry bulb temperature and wet bulb temperature until local yellowing of the leaf surface occurs; wherein, the third target dry bulb temperature is greater than the first target dry bulb temperature, and the third target wet bulb temperature is greater than or equal to the first target wet bulb temperature.

[0011] Color fixation stage: Control the fan rotation to raise the dry-bulb temperature to the fourth target dry-bulb temperature at a preset third heating rate and a third preset temperature gradient between different temperature monitoring points, and control the wet-bulb temperature at the fourth target wet-bulb temperature. Maintain the dry-bulb temperature and wet-bulb temperature until the entire leaf surface turns yellow and local red spots appear; wherein, the fourth target dry-bulb temperature is greater than the third target dry-bulb temperature, and the fourth target wet-bulb temperature is less than the first target wet-bulb temperature;

[0012] Drying stage: Control the fan rotation to raise the dry-bulb temperature to the fifth target dry-bulb temperature at the preset fourth heating rate and the fourth preset temperature gradient between different temperature monitoring points, and control the wet-bulb temperature at the fifth target wet-bulb temperature. Maintain the dry-bulb temperature and wet-bulb temperature until red spots appear on 40% of the leaf surface; wherein, the fifth target dry-bulb temperature is greater than the fourth target dry-bulb temperature, and the fifth target wet-bulb temperature is greater than or equal to the fourth target wet-bulb temperature;

[0013] Cooling and rehumidification stage: Stop heating and force ventilation until the dry bulb temperature returns to room temperature. The wet bulb temperature is 3-5°C lower than the dry bulb temperature.

[0014] Preferably, before the cooling and rehydration stage, there is also a stage of roasting and drying the stems: controlling the fan to rotate, raising the dry bulb temperature to the sixth target dry bulb temperature at a preset fifth heating rate and a fifth preset temperature gradient between different temperature monitoring points, and controlling the wet bulb temperature at the sixth target wet bulb temperature, maintaining the dry bulb temperature and wet bulb temperature until 70% of the leaf surface shows red spots and the midrib dries; wherein, the sixth target dry bulb temperature is greater than the fifth target dry bulb temperature, and the sixth target wet bulb temperature is greater than or equal to the fifth target wet bulb temperature.

[0015] Preferably, the temperature gradient is obtained by statistical analysis of the temperature field distribution at each temperature monitoring point.

[0016] Preferably, the dry-bulb temperature and wet-bulb temperature are the average temperature field value and the average humidity field value of multiple temperature monitoring points in the drying oven, respectively.

[0017] Preferably, the fan speed is controlled by temperature gradient coupling.

[0018] Preferably, the maximum value of the second preset temperature gradient is greater than the maximum value of the first preset temperature gradient, the maximum value of the third preset temperature gradient is less than the maximum value of the first preset temperature gradient, and the maximum value of the fourth preset temperature gradient is greater than the maximum value of the third preset temperature gradient.

[0019] Preferably, the fifth preset temperature gradient is greater than the fourth preset temperature gradient.

[0020] Preferably, the first heating rate, the second heating rate, and the third heating rate are the same.

[0021] Preferably, the fourth heating rate is the same as the fifth heating rate.

[0022] Preferably, the fourth heating rate is greater than the first heating rate.

[0023] Preferably, the first preset time period is 12 to 24 hours.

[0024] Preferably, the second preset time period is 6 to 8 hours.

[0025] Preferably, the preset pole spacing is 15-20 cm, the preset blade spacing is 1.5-3 cm, and the preset monitoring spacing is 1-1.5 m.

[0026] Preferably, the first target dry-bulb temperature is 39–41 °C, and the first target wet-bulb temperature is 38–40 °C; the second target dry-bulb temperature is 36–38 °C, and the second target wet-bulb temperature is 35–37 °C; the third target dry-bulb temperature is 44–46 °C, and the third target wet-bulb temperature is 40–42 °C; the fourth target dry-bulb temperature is 50–53 °C, and the fourth target wet-bulb temperature is 36–38 °C; the fifth target dry-bulb temperature is 56–58 °C, and the fifth target wet-bulb temperature is 38–40 °C.

[0027] Preferably, the dry-bulb temperature of the sixth target is 68–70 °C, and the wet-bulb temperature of the sixth target is 39–41 °C.

[0028] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0030] Figure 1 A flowchart of a preferred embodiment of the method for improving the stability of cinnabar tobacco curing provided in this application;

[0031] Figure 2 A schematic diagram of temperature and humidity field control for the preparation of cinnabar tobacco leaves provided in this application. Detailed Implementation

[0032] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0033] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0034] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0035] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0036] This application provides a method for curing vermilion tobacco leaves to improve the stability of nicotine extraction. By pre-curing and softening the tobacco leaves, a preliminary pre-conversion of the internal substances is achieved. Through reasonable spatial distribution and temperature gradient control during curing, the stability of nicotine extraction is improved. Furthermore, during the enzymatic conversion stage, the rate of moisture loss from the tobacco leaf surface is controlled by first raising and then lowering the temperature. Utilizing the principle of condensation in saturated humid air, excessive moisture loss during curing is prevented, ensuring that the nicotine-converting enzyme remains in a highly active state, which is conducive to the formation of nicotine and helps improve the nicotine extraction rate. Simultaneously, based on the optimal temperature and humidity control for the accumulation reaction of colorimetric substances, a 68℃ roasting and drying stage is added. Under high temperature and low humidity conditions, the reaction between nicotine and anthraquinone substances is effectively guaranteed, promoting the nicotine extraction and stability of the vermilion tobacco leaves. Through strict condition control and maintaining a uniform spatial temperature gradient, both the full occurrence of relevant reactions and the stable expression of the vermilion tobacco leaf's characteristic flavor are ensured.

[0037] like Figure 1 As shown, the method for improving the stability of cinnabar tobacco leaf preparation provided in this application includes:

[0038] S110: Spreading and drying stage: After harvesting the appropriate or mature cinnabar tobacco leaves, spread them thinly at room temperature and dry them for the first preset time period.

[0039] As an example, the first preset time period is 12 to 24 hours.

[0040] S120: Preparation stage: In the curing barn, hangers are set up with a preset pole spacing, and vermilion tobacco leaves are hung on the hangers with a preset leaf spacing to avoid overlapping of the vermilion tobacco leaves; and multiple temperature monitoring points and humidity monitoring points are set up in the three-dimensional space of the curing barn with a preset monitoring spacing.

[0041] As an example, the preset pole spacing is 15-20 cm, the preset blade spacing is 1.5-3 cm, and the preset monitoring spacing is 1-1.5 m.

[0042] Multiple temperature monitoring points are evenly arranged at preset monitoring intervals inside the curing oven, which helps to monitor the temperature at different locations inside the curing oven and facilitates the implementation of preset temperature gradients in each subsequent stage.

[0043] S130: Enzymatic Conversion Stage: Controlling the fan rotation, the dry-bulb temperature is raised to the first target dry-bulb temperature at a preset first heating rate and a first preset temperature gradient between different temperature monitoring points. The wet-bulb temperature is then controlled at the first target wet-bulb temperature. Subsequently, the dry-bulb temperature is lowered to the second target dry-bulb temperature. After condensation appears on the tobacco leaf surface, the wet-bulb temperature is controlled at the second target wet-bulb temperature. The dry-bulb and wet-bulb temperatures are maintained until the leaf surface softens, and this process continues for a second preset time period. The second target wet-bulb temperature is lower than the first target wet-bulb temperature.

[0044] As an example, the temperature gradient is obtained by statistically analyzing the temperature field distribution at each temperature monitoring point.

[0045] As an example, the dry-bulb temperature and wet-bulb temperature are the average temperature field values ​​from multiple temperature monitoring points and the average humidity field values ​​from multiple humidity monitoring points in the drying oven, respectively. Figure 2 This is a schematic diagram of the temperature and humidity field control for the curing of cinnabar tobacco leaves provided in this application, where xyz are the three-dimensional coordinates of the curing barn, and ▽T is the spatial temperature and humidity distribution gradient.

[0046] As an example, the fan speed is controlled by temperature gradient coupling.

[0047] As an example, the first heating rate is 1 °C / h, the maximum value of the first preset temperature gradient is 2 °C, the first target dry-bulb temperature is 39–41 °C, and the first target wet-bulb temperature is 38–40 °C. The second target dry-bulb temperature is 36–38 °C, the second target wet-bulb temperature is 35–37 °C, and the second preset time period is 6–8 hours.

[0048] The optimal temperature for enzymatic reactions in cinnabar tobacco leaves is 38 ℃, and the conversion rate of nicotine to nornicotine can reach about 90% when the catalytic reaction is sustained for 6-12 h.

[0049] The enzymatic conversion stage employs a process of first raising the temperature and then lowering it to prevent the rapid release of moisture from the tobacco leaf surface, which could lead to incomplete enzymatic reactions. A more complete enzymatic reaction results in a higher sand yield. Therefore, the enzymatic conversion stage of this application helps to improve the sand yield of tobacco leaves.

[0050] S140: Pigment Deposition Stage: Control the fan rotation to raise the dry-bulb temperature to the third target dry-bulb temperature at a preset second heating rate and a second preset temperature gradient between different temperature monitoring points, while maintaining the wet-bulb temperature at the third target wet-bulb temperature until localized yellowing of the leaf surface occurs. Specifically, the third target dry-bulb temperature is greater than the first target dry-bulb temperature, and the third target wet-bulb temperature is greater than or equal to the first target wet-bulb temperature. The maximum value of the second preset temperature gradient is greater than the maximum value of the first preset temperature gradient.

[0051] As an example, the second heating rate is 1 ℃ / h, the maximum value of the second preset temperature gradient is 5 ℃, the third target dry bulb temperature is 44~46 ℃, and the third target wet bulb temperature is 40~42 ℃.

[0052] S150: Color Fixing Stage: Control the fan rotation to raise the dry-bulb temperature to the fourth target dry-bulb temperature at a preset third heating rate and a third preset temperature gradient between different temperature monitoring points. Maintain the wet-bulb temperature at the fourth target wet-bulb temperature until the entire leaf surface turns yellow and localized red spots appear. The fourth target dry-bulb temperature is higher than the third target dry-bulb temperature, and the fourth target wet-bulb temperature is lower than the first target wet-bulb temperature. The maximum value of the third preset temperature gradient is less than the maximum value of the first preset temperature gradient.

[0053] As an example, the first heating rate, the second heating rate, and the third heating rate are the same.

[0054] As an example, the third heating rate is 1 °C / h, and the maximum value of the third preset temperature gradient is 1 °C. The fourth target dry-bulb temperature is 50–53 °C, and the fourth target wet-bulb temperature is 36–38 °C.

[0055] S160: Drying Stage: Control the fan rotation to raise the dry-bulb temperature to the fifth target dry-bulb temperature at a preset fourth heating rate and a fourth preset temperature gradient between different temperature monitoring points. Maintain the wet-bulb temperature at the fifth target wet-bulb temperature, and keep both dry-bulb and wet-bulb temperatures until red spots appear on 40% of the leaf surface. Specifically, the fifth target dry-bulb temperature is greater than the fourth target dry-bulb temperature, and the fifth target wet-bulb temperature is greater than or equal to the fourth target wet-bulb temperature. The maximum value of the fourth preset temperature gradient is greater than the maximum value of the third preset temperature gradient, and the fourth heating rate is greater than the first heating rate.

[0056] As an example, the fourth heating rate is 2 °C / h, and the maximum value of the fourth preset temperature gradient is 2 °C. The fifth target dry-bulb temperature is 56–58 °C, and the fifth target wet-bulb temperature is 38–40 °C.

[0057] S180: Cooling and Moisturizing Stage: Stop heating and force ventilation until the dry bulb temperature returns to room temperature. The wet bulb temperature is 3-5°C lower than the dry bulb temperature.

[0058] Preferably, prior to the cooling and rehydration stage, the process further includes:

[0059] S170: Drying and Reddening Stage: Control the fan rotation to raise the dry-bulb temperature to the sixth target dry-bulb temperature at the preset fifth heating rate and the fifth preset temperature gradient between different temperature monitoring points. Maintain the wet-bulb temperature at the sixth target wet-bulb temperature, keeping both dry-bulb and wet-bulb temperatures until 70% of the leaf surface shows red spots and the midrib dries. Specifically, the sixth target dry-bulb temperature is higher than the fifth target dry-bulb temperature, and the sixth target wet-bulb temperature is greater than or equal to the fifth target wet-bulb temperature. The fifth preset temperature gradient is greater than the fourth preset temperature gradient, and the fourth heating rate is the same as the fifth heating rate.

[0060] As an example, the fifth heating rate is 2 °C / h, and the maximum value of the fifth preset temperature gradient is 5 °C. The sixth target dry-bulb temperature is 68–70 °C, and the sixth target wet-bulb temperature is 39–41 °C.

[0061] The accumulation of chromogenic substances is mainly through chemical reactions. Maintaining a reaction temperature of around 68 ℃ is conducive to the accumulation of red substances, while lower temperatures are not. Furthermore, a high-temperature and high-humidity environment promotes the accumulation and color development of red substances.

[0062] As mentioned above, at each stage, the temperature field in the entire curing barn satisfies a certain temperature gradient, making the color development process of tobacco leaves at each location controllable. Furthermore, by controlling the temperature gradient, the distribution of sand content of tobacco leaves at different locations in the entire curing barn can be controlled. Compared with existing technologies, the concentration of sand content distribution in the entire curing barn is relatively high, meaning that the sand content stability is relatively high.

[0063] The modulation method of this application will be further illustrated below through three embodiments and one comparative example:

[0064] Example 1

[0065] Mature cinnabar tobacco varieties, such as Cinnabar No. 2, were harvested and spread thinly at room temperature for 12 hours. They were then placed in a dense electric curing room for curing. The specific curing steps are as follows:

[0066] S1: Preparation for curing: 1) Hang the above tobacco leaves on the sticks with a leaf spacing of 1.5 cm and a stick spacing of 15 cm to avoid overlapping; 2) Set up a temperature and humidity monitoring point every 1 m in the three-dimensional space of the curing barn.

[0067] S2: Enzymatic conversion stage: 1) Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 2 ℃, raise the dry bulb temperature to 41 ℃, and control the wet bulb temperature at 38 ℃; 2) Cool down, lower the dry bulb temperature to 36 ℃, and after condensation appears on the surface of the tobacco leaves, control the wet bulb temperature to 35 ℃, maintain the dry bulb temperature and wet bulb temperature until the leaf surface softens, and continue for 6 h.

[0068] S3: Pigment deposition stage: Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 5 ℃, raise the dry bulb temperature to 44 ℃, and control the wet bulb temperature at 40 ℃, and maintain the dry bulb temperature and wet bulb temperature until local yellowing of the leaf surface occurs.

[0069] S4: Color fixation stage: Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 1 ℃, raise the dry bulb temperature to 50 ℃, and control the wet bulb temperature at 36 ℃. Maintain this dry bulb temperature and wet bulb temperature until the entire leaf surface turns yellow and local red spots appear.

[0070] S5: Drying stage: Control the fan speed at an average rate of 2 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 2 ℃, raise the dry bulb temperature to 58 ℃, and control the wet bulb temperature at 40 ℃. Maintain this dry bulb temperature and wet bulb temperature until 40% of the leaf surface shows red spots.

[0071] S6: Drying the stems: Control the fan speed at an average rate of 2 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 5 ℃, raise the dry bulb temperature to 68 ℃, and control the wet bulb temperature at 39 ℃. Maintain this dry bulb temperature and wet bulb temperature until 70% of the leaf surface shows red spots and the main vein dries.

[0072] S7: Cooling and Moisturizing Stage: Stop heating and force ventilation until the dry bulb temperature returns to room temperature, and the wet bulb temperature is 5°C lower than the dry bulb temperature.

[0073] After processing, the resulting cinnabar tobacco has a uniform appearance, a golden to reddish-brown color, obvious cinnabar spots, a cinnabar yield of 79.1%, and the proportion of cinnabar red patches on a single tobacco leaf is 40%-63%.

[0074] Example 2

[0075] Mature cinnabar tobacco varieties, such as Cinnabar No. 2, were harvested and spread thinly at room temperature for 18 hours. They were then placed in a dense electric curing room for curing. The specific curing steps are as follows:

[0076] S1: Preparation for curing: 1) Hang the tobacco leaves on the sticks with a leaf spacing of 3 cm and a stick spacing of 20 cm to avoid overlapping; 2) Set up a temperature and humidity monitoring point every 1 m in the three-dimensional space of the curing barn.

[0077] S2: Enzymatic conversion stage: 1) Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 2 ℃, raise the dry bulb temperature to 41 ℃, and control the wet bulb temperature at 38 ℃; 2) Cool down to reduce the dry bulb temperature to 36 ℃. After condensation appears on the surface of the tobacco leaves, control the wet bulb temperature at 35 ℃, maintain this dry bulb temperature and wet bulb temperature until the leaf surface softens, and continue for 8 hours.

[0078] S3: Pigment deposition stage: Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 5 ℃, raise the dry bulb temperature to 46 ℃, and control the wet bulb temperature at 42 ℃, and maintain the dry bulb temperature and wet bulb temperature until local yellowing of the leaf surface occurs.

[0079] S4: Color fixation stage: Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 1 ℃, raise the dry bulb temperature to 53 ℃, and control the wet bulb temperature at 38 ℃. Maintain this dry bulb temperature and wet bulb temperature until the entire leaf surface turns yellow and local red spots appear.

[0080] S5: Drying stage: Control the fan speed at an average rate of 2 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 2 ℃, raise the dry bulb temperature to 56 ℃, and control the wet bulb temperature at 38 ℃. Maintain this dry bulb temperature and wet bulb temperature until 40% of the leaf surface shows red spots.

[0081] S6: Drying the stems: Control the fan speed at an average rate of 2 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 5 ℃, raise the dry bulb temperature to 70 ℃, and control the wet bulb temperature at 41 ℃. Maintain this dry bulb temperature and wet bulb temperature until 70% of the leaf surface shows red spots and the main vein dries.

[0082] S7: Cooling and Moisturizing Stage: Stop heating and force ventilation until the dry bulb temperature returns to room temperature, and the wet bulb temperature is 5°C lower than the dry bulb temperature.

[0083] After processing, the resulting cinnabar tobacco has a uniform appearance, a golden to reddish-brown color, a cinnabar yield of 73.6%, and a cinnabar red patch that accounts for 38%-59% of the leaf area in a single tobacco leaf.

[0084] Example 3

[0085] Harvested, fully matured Zhusha No. 2 tobacco varieties were spread thinly at room temperature and dried for 24 hours, then placed in a gas-fired curing room for curing. The specific curing steps are as follows:

[0086] S1: Preparation for curing: 1) Hang the above tobacco leaves on the sticks with a leaf spacing of 2 cm and a stick spacing of 20 cm to avoid overlapping; 2) Set up a temperature and humidity monitoring point every 1.5 m in the three-dimensional space of the curing barn.

[0087] S2: Enzymatic conversion stage: 1) Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 2 ℃, raise the dry bulb temperature to 40 ℃, and control the wet bulb temperature at 39 ℃; 2) Cool down to reduce the dry bulb temperature to 37 ℃. After condensation appears on the surface of the tobacco leaves, control the wet bulb temperature at 35 ℃, maintain this dry bulb temperature and wet bulb temperature until the leaf surface softens, and continue for 7 h.

[0088] S3: Pigment deposition stage: Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 5 ℃, raise the dry bulb temperature to 46 ℃, and control the wet bulb temperature at 42 ℃, and maintain the dry bulb temperature and wet bulb temperature until local yellowing of the leaf surface occurs.

[0089] S4: Color fixation stage: Control the fan speed at an average rate of 1 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 1 ℃, raise the dry bulb temperature to 52 ℃, and control the wet bulb temperature at 37 ℃. Maintain this dry bulb temperature and wet bulb temperature until the entire leaf surface turns yellow and local red spots appear.

[0090] S5: Drying stage: Control the fan speed at an average rate of 2 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 2 ℃, raise the dry bulb temperature to 57 ℃, and control the wet bulb temperature at 39 ℃. Maintain this dry bulb temperature and wet bulb temperature until 40% of the leaf surface shows red spots.

[0091] S6: Drying the stems: Control the fan speed at an average rate of 2 ℃ / h to ensure that the temperature gradient at different temperature monitoring points is less than 5 ℃, raise the dry bulb temperature to 69 ℃, and control the wet bulb temperature at 40 ℃. Maintain this dry bulb temperature and wet bulb temperature until 70% of the leaf surface shows red spots and the main vein dries.

[0092] S7: Cooling and Moisturizing Stage: Stop heating and force ventilation until the dry bulb temperature returns to room temperature, and the wet bulb temperature is 5°C lower than the dry bulb temperature.

[0093] After processing, the resulting cinnabar tobacco has a uniform appearance, a golden to reddish-brown color, a cinnabar yield of 81.9%, and the proportion of cinnabar red patches in a single tobacco leaf reaches 39%-65% of the leaf area.

[0094] Compare with Example 1

[0095] Experimental method: Mature cinnabar tobacco variety cinnabar 2 was harvested and divided into two equal parts according to appearance characteristics, which were designated as A and B respectively. Sample A was processed using the processing method of this application, while sample B was processed using the traditional processing method. After processing, the cinnabar tobacco leaf cinnabar yield and appearance characteristics of each process were measured.

[0096] The comparison results are as follows:

[0097] As shown in Table 1, the average sand output rate of the modulation method of this application is stable at around 71.5%, with a small range and better appearance, which is significantly better than the traditional modulation method. This indicates that the modulation method of this application has significant application and promotion value.

[0098] Table 1. Effects of different modulation processes on the sand yield and appearance of vermilion-treated tobacco leaves.

[0099]

[0100] Note: The data in the table are calculated from 30 samples randomly selected from each batch, and the average value is recorded as one. Each sample was prepared three times, and the average value of the three preparations was taken.

[0101] This application controls the material transformation process of cinnabar tobacco leaves under optimal intrinsic reaction conditions through intrinsic enzymatic and chemical reaction control, maximizing the formation of the target product and the stability of the cinnabar output. Furthermore, this application optimizes the temperature field control in the curing barn, achieving a uniform temperature distribution throughout the barn through appropriate temperature gradient control, thus ensuring the stability of the microenvironment for tobacco leaf curing.

[0102] In summary, this application combines the control of temperature and humidity fields in the modulation of cinnabar tobacco with the modulation physiological and biochemical processes. Based on the intrinsic physicochemical reaction process of cinnabar tobacco, it precisely controls the sand-producing reaction conditions of cinnabar tobacco, thereby improving the sand-producing stability of cinnabar tobacco leaves. The various stages are sequentially connected, with the observation of the saturation reaction process as the key indicator. Global gradient control of the temperature and humidity field ensures the uniformity of the temperature and humidity field distribution, achieving uniform reaction conditions in all regions, while simultaneously improving sand-producing stability.

[0103] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A method for preparing cinnabar tobacco leaves to improve the stability of cinnabar output, characterized in that, include: Spreading and drying stage: After harvesting the appropriate or mature cinnabar tobacco leaves, spread them out at room temperature and dry them for the first preset time period. Preparation stage: In the curing room, hangers are set up with a preset pole spacing, and the vermilion tobacco leaves are hung on the hangers with a preset leaf spacing to avoid overlapping of the vermilion tobacco leaves; Multiple temperature and humidity monitoring points are set at preset monitoring intervals within the three-dimensional space of the drying room; Enzymatic conversion stage: The fan is controlled to rotate at a preset first heating rate and a preset temperature gradient between different temperature monitoring points to raise the dry bulb temperature to the first target dry bulb temperature and control the wet bulb temperature at the first target wet bulb temperature. Then, the dry bulb temperature is lowered to the second target dry bulb temperature. After condensation appears on the surface of the tobacco leaf, the wet bulb temperature is controlled at the second target wet bulb temperature. The dry bulb temperature and wet bulb temperature are maintained until the leaf surface softens and this is continued for a second preset time period. The second target wet bulb temperature is lower than the first target wet bulb temperature. Pigment deposition stage: Control the fan rotation to raise the dry bulb temperature to the third target dry bulb temperature at a preset second heating rate and a second preset temperature gradient between different temperature monitoring points, and control the wet bulb temperature at the third target wet bulb temperature, maintaining the dry bulb temperature and wet bulb temperature until local yellowing of the leaf surface occurs; wherein, the third target dry bulb temperature is greater than the first target dry bulb temperature, and the third target wet bulb temperature is greater than or equal to the first target wet bulb temperature; Color fixation stage: Control the fan rotation to raise the dry-bulb temperature to the fourth target dry-bulb temperature at a preset third heating rate and a third preset temperature gradient between different temperature monitoring points, and control the wet-bulb temperature at the fourth target wet-bulb temperature, maintaining the dry-bulb temperature and wet-bulb temperature until the entire leaf surface turns yellow and local red spots appear; wherein, the fourth target dry-bulb temperature is greater than the third target dry-bulb temperature, and the fourth target wet-bulb temperature is less than the first target wet-bulb temperature; Drying stage: Control the fan rotation to raise the dry-bulb temperature to the fifth target dry-bulb temperature at a preset fourth heating rate and a fourth preset temperature gradient between different temperature monitoring points, and control the wet-bulb temperature at the fifth target wet-bulb temperature, maintaining the dry-bulb and wet-bulb temperatures until red spots appear on 40% of the leaf surface; wherein, the fifth target dry-bulb temperature is greater than the fourth target dry-bulb temperature, and the fifth target wet-bulb temperature is greater than or equal to the fourth target wet-bulb temperature; Cooling and rehumidification stage: Stop heating and force ventilation until the dry bulb temperature returns to room temperature. The wet bulb temperature is 3-5°C lower than the dry bulb temperature.

2. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The temperature gradient was obtained by statistical analysis of the temperature field distribution at each temperature monitoring point.

3. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The dry-bulb temperature and wet-bulb temperature are the average temperature field value and the average humidity field value of multiple temperature monitoring points in the drying oven, respectively.

4. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The fan speed is controlled by temperature gradient coupling.

5. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The maximum value of the second preset temperature gradient is greater than the maximum value of the first preset temperature gradient, the maximum value of the third preset temperature gradient is less than the maximum value of the first preset temperature gradient, and the maximum value of the fourth preset temperature gradient is greater than the maximum value of the third preset temperature gradient.

6. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The first heating rate, the second heating rate, and the third heating rate are the same.

7. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The first preset time period is 12 to 24 hours.

8. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The second preset time period is 6 to 8 hours.

9. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The preset pole spacing is 15–20 cm, the preset blade spacing is 1.5–3 cm, and the preset monitoring spacing is 1–1.5 m.

10. The method for improving the stability of cinnabar tobacco leaf preparation according to claim 1, characterized in that, The first target dry-bulb temperature is 39–41 °C, and the first target wet-bulb temperature is 38–40 °C; the second target dry-bulb temperature is 36–38 °C, and the second target wet-bulb temperature is 35–37 °C; the third target dry-bulb temperature is 44–46 °C, and the third target wet-bulb temperature is 40–42 °C; the fourth target dry-bulb temperature is 50–53 °C, and the fourth target wet-bulb temperature is 36–38 °C; the fifth target dry-bulb temperature is 56–58 °C, and the fifth target wet-bulb temperature is 38–40 °C.

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