A simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant.

Abstract

This application discloses a simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the tobacco plant, comprising the following steps: S1, Harvesting: Once the upper tobacco leaves reach maturity, the leaves, along with their stems, are cut off one by one from the tobacco plant, ensuring each leaf retains 1-2 cm of the lower stem. S2, Tying / Hanging: The tobacco leaves with short stems are tied / hung on both sides of a woven tobacco pole using a figure-eight wrapping method, and then placed in a shady place. S3, Loading: All the tied / hung tobacco poles are transferred to the curing barn and arranged in an orderly manner according to a specific arrangement. S4, Curing: Curing is performed using a high-humidity yellowing and medium-humidity withering and color-fixing curing process. This application uses single leaves with 1-2 cm of stem for harvesting and curing. Compared with traditional techniques, this method reduces the harvesting, handling, and drying of a large amount of stems, thereby reducing labor intensity, shortening curing time, and minimizing the loss of aroma substances in the tobacco leaves due to long drying periods and high temperatures, thus improving the curing quality.

Description

Technical Field

[0001] This application relates to the field of tobacco leaf harvesting and curing technology, and in particular to a simple method for harvesting and curing single tobacco leaves with stems from the upper part of the tobacco plant. Background Technology

[0002] Currently, the main problems with the upper leaves of flue-cured tobacco in China are as follows: Fresh tobacco leaves in the field have low moisture content and are relatively thick, with most harvested leaves being still at a relatively mature stage. In particular, the last curing of the conventional harvest with only 2-3 leaves results in excessive nutrient supply and overly thick leaves. After curing, the leaves appear underdeveloped, with a darker color, prone to greenish discoloration, thick and stiff appearance, slight oil content, and uneven color. The chemical composition shows high levels of starch, nicotine, and total nitrogen, but a low sugar-alkali ratio, leading to poor balance. The smoking quality is also high, with a strong greenish odor and high irritation, limiting industrial usability. To address these issues, some scholars have developed a technique for harvesting and curing the upper leaves with 4-6 leaves and stems, which can effectively improve the usability of the upper tobacco. However, this technique suffers from a series of problems, including high labor intensity, high labor costs, long curing time, and high temperatures during the drying stage. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a simplified method for harvesting and curing single leaves with stems from the upper part of flue-cured tobacco. This method uses single leaves with stems of 1-2 cm for harvesting and curing. Compared with the traditional method of harvesting and curing 4-6 upper leaves with stems, it reduces the harvesting, handling, and drying of a large amount of stems, thereby reducing labor intensity, shortening curing time, and reducing the loss of aroma substances in tobacco leaves due to long drying periods and high temperatures, thus improving curing quality.

[0004] The technical solution provided by this invention is as follows:

[0005] A simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant includes the following steps:

[0006] S1. Harvesting: When the upper tobacco leaves reach maturity, cut the tobacco leaves and stems off the tobacco plant one by one, keeping each tobacco leaf with 1-2 cm of the lower stem attached.

[0007] S2. Binding / Hanging Tobacco: Use a rope to bind / hang tobacco leaves with short stems on both sides of the tobacco pole in a figure-eight pattern. Place the bound / hanged tobacco leaves in a shady place.

[0008] S3. Loading tobacco: Transfer all the tied / hanging tobacco poles into the curing room and arrange them in an orderly manner according to a certain arrangement method;

[0009] S4. Baking: Baking is carried out using a high-humidity yellowing and medium-humidity withering and color-fixing baking process.

[0010] Preferably, steps S1 to S3 are completed within one day and the baking is carried out on the same day.

[0011] Preferably, the maturity standard of the upper tobacco leaves in step S1 is as follows: the basic color of the tobacco leaves is yellow, the leaf surface is fully yellowed, the main vein turns white, the lateral veins are basically all white, the leaf auricles are light yellow or have obvious yellow spots, the leaf tips droop, the leaf edges are wrinkled, the stem-leaf angle is significantly increased, and the maturity spots are obvious.

[0012] Preferably, in step S2, each tobacco wicker pole has 150-170 tobacco leaves, more preferably 160 leaves. The tobacco wicker pole must be fully tied / hung, with 4-6cm of empty pole left at both ends. When tying / hanging the tobacco leaves, avoid damaging the leaves by friction with the ground.

[0013] Preferably, in step S3, when transferring the tobacco rods into the curing barn, tobacco is loaded simultaneously from the heating chamber partition wall, from the inside out, in a staggered manner in the upper, middle and lower layers. The tobacco rods in the same layer are evenly distributed, and the curing barn must be filled completely without leaving any gaps.

[0014] Preferably, in step S3, the amount of tobacco loaded per kang (heated brick bed) is 300-340 sticks, more preferably 320 sticks.

[0015] Preferably, in step S3, tobacco leaves of the same variety and with similar overall quality should be placed in the same curing barn, without mixing them. The most representative tobacco leaves should be placed at the observation window of the curing barn to facilitate monitoring the changes in the tobacco leaves.

[0016] Preferably, the baking process for high-humidity yellowing and medium-humidity wilting and color fixing in step S4 includes the following steps:

[0017] S401, Yellowing stage: After the curing barn is filled with tobacco, it is ignited immediately. The temperature inside the curing barn rises and the tobacco leaves are cured until they turn 30-40% yellow. The temperature is maintained for 10-14 hours. After the tobacco leaves start to sweat noticeably, they begin to release moisture. The temperature is raised to a certain level and the tobacco leaves are cured until they turn 70-80% yellow. The temperature is maintained for 18-24 hours. The tobacco leaves become soft and collapse. The temperature is raised to a certain level and the tobacco leaves in the high-temperature greenhouse turn 90-100% yellow. The temperature is maintained for 14-22 hours. The tobacco leaves in the high-temperature greenhouse have hooked tips and curled edges, and the color of the tobacco leaves reaches the point of yellow leaves with green veins.

[0018] S402, Color Fixing Period: Baking until the tobacco leaves in the low-temperature greenhouse turn yellow (9-10% yellow), maintaining the temperature for 10-16 hours, the tips and edges of the tobacco leaves curl, and the color of the tobacco leaves reaches yellow leaves with green veins. Continue to raise the temperature to a certain level and bake until the tobacco leaves are yellow leaves with white veins. Generally, maintain the temperature for 16-20 hours. Continue to raise the temperature to a certain level and bake until the tobacco leaves are basically completely dry, the main vein is more than one-third dry, and the tobacco leaves are in a large rolled state. Maintain the temperature for 12-14 hours.

[0019] S403, Drying stage: Continue to raise the temperature to a certain level, maintain the temperature for 18-24 hours, and stop baking when the main veins of the tobacco leaves are completely dry.

[0020] Preferably, in step S401, the initial temperature is increased to a dry-bulb temperature of 38±0.5℃ and a wet-bulb temperature of 37±0.5℃; in the middle stage, the temperature is increased to a dry-bulb temperature of 40±0.5℃ and a wet-bulb temperature of 38±0.5℃; and in the later stage, the temperature is increased to a dry-bulb temperature of 42±0.5℃ and a wet-bulb temperature of 37±0.5℃. In step S402, the initial temperature is increased to a dry-bulb temperature of 47±0.5℃ and a wet-bulb temperature of 37±0.5℃; in the later stage, the temperature is increased to a dry-bulb temperature of 54±0.5℃ and a wet-bulb temperature of 39±0.5℃. In step S403, the dry-bulb temperature is increased to 65±1℃ and the wet-bulb temperature is increased to 42±1℃.

[0021] Preferably, the heating rate in step S401 is 1℃ / h, the heating rate in step S402 is 0.3℃ / h, and the heating rate in step S403 is 1℃ / h.

[0022] This application has the following advantages over the prior art:

[0023] The present invention provides a simplified method for harvesting and curing flue-cured tobacco leaves by harvesting single leaves with stems. The upper leaves are harvested together with the stems at the lower part of the plant, and the stem length is controlled to be 1-2 cm. Compared with the traditional method of harvesting and curing 4-6 upper leaves with stems, this method reduces the harvesting, handling, and drying of a large amount of stems, thereby reducing labor intensity, shortening curing time, and reducing the loss of aroma substances in tobacco leaves due to long drying period and high temperature, thus improving curing quality. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] This invention provides a simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant, comprising the following steps:

[0026] S1. Harvesting: When the upper tobacco leaves reach maturity, cut the tobacco leaves and stems off the tobacco plant one by one, keeping each tobacco leaf with 1-2 cm of the lower stem attached.

[0027] S2. Binding / Hanging Tobacco: Use a rope to bind / hang tobacco leaves with short stems on both sides of the tobacco pole in a figure-eight pattern. Place the bound / hanged tobacco leaves in a shady place.

[0028] S3. Loading tobacco: Transfer all the tied / hanging tobacco poles into the curing room and arrange them in an orderly manner according to a certain arrangement method;

[0029] S4. Baking: Baking is carried out using a high-humidity yellowing and medium-humidity withering and color-fixing baking process.

[0030] In this embodiment, steps S1 to S3 are completed within one day and the baking is carried out on the same day.

[0031] In this embodiment, the maturity standard of the upper tobacco leaves in step S1 is as follows: the basic color of the tobacco leaves is yellow, the leaf surface is fully yellowed, the main vein turns white, the branch veins are basically all white, the leaf auricles are light yellow or have obvious yellow spots, the leaf tips droop, the leaf edges are wrinkled, the angle between the stem and leaves is significantly increased, and the maturity spots are obvious.

[0032] In this embodiment, each tobacco wicker pole has 150 to 170 tobacco leaves, preferably 160 leaves, in step S2. The tobacco wicker pole must be fully tied / hung, and 4 to 6 cm of empty pole should be left at both ends. When tying / hanging the tobacco leaves, avoid damaging the leaves by friction with the ground.

[0033] In this embodiment, when transferring the tobacco rods into the curing barn in step S3, tobacco is loaded simultaneously from the heating chamber partition wall, from the inside out, with the upper, middle and lower layers staggered. The tobacco rods on the same layer are evenly distributed, and the curing barn must be filled completely without leaving any gaps.

[0034] In this embodiment, the amount of tobacco loaded per kang (heated brick bed) in step S3 is 300-340 sticks, preferably 320 sticks.

[0035] In this embodiment, in step S3, tobacco leaves of the same variety and with similar overall quality should be placed in the same curing barn, without mixing them. The most representative tobacco leaves should be placed at the observation window of the curing barn to facilitate monitoring the changes in the tobacco leaves.

[0036] In this embodiment, the baking process for high-humidity yellowing and medium-humidity wilting and color fixing in step S4 includes the following steps:

[0037] S401, Yellowing Stage: After the curing barn is filled with tobacco, it is immediately ignited. The temperature inside the barn rises and the tobacco leaves are cured until they turn 30-40% yellow. The temperature is stabilized for 10-14 hours. After the tobacco leaves start to sweat noticeably, they begin to release moisture. The temperature is then raised to a certain level and the tobacco leaves are cured until they turn 70-80% yellow. The temperature is stabilized for 18-24 hours. The tobacco leaves become soft and collapse. The temperature is then raised to a certain level and the tobacco leaves in the high-temperature shed turn 90-100% yellow. The temperature is stabilized for 14-22 hours. The tobacco leaves in the high-temperature shed have hooked tips and curled edges, and the color of the tobacco leaves reaches the point of yellow leaves with green veins (generally, the curing barn is divided into three layers, and the temperature of the upper and lower layers is not uniform. If it is an upward airflow type, the lower layer is the high-temperature layer and the upper layer is the low-temperature layer. The yellowing and drying progress of the tobacco leaves are different).

[0038] S402, Color Fixing Period: Baking until the tobacco leaves in the low-temperature greenhouse turn 9-10% yellow, maintaining the temperature for 10-16 hours, the tips and edges of the tobacco leaves in the low-temperature greenhouse become hooked and curled, and the color of the tobacco leaves reaches the stage of yellow leaves with green veins (when the tobacco leaves in the high-temperature layer enter the color fixing period, the tobacco leaves in the low-temperature layer are still in the yellowing period), continue to raise the temperature to a certain temperature, and bake until the tobacco leaves are yellow leaves with white veins, generally maintaining the temperature for 16-20 hours, continue to raise the temperature to a certain temperature, and bake until the tobacco leaves are basically completely dry, the main veins are more than one-third dry, and the tobacco leaves are in a large rolled state, maintaining the temperature for 12-14 hours;

[0039] S403, Drying stage: Continue to raise the temperature to a certain level, maintain the temperature for 18-24 hours, and stop baking when the main veins of the tobacco leaves are completely dry.

[0040] In this embodiment, in step S401, the initial temperature is increased to a dry-bulb temperature of 38±0.5℃ and a wet-bulb temperature of 37±0.5℃; in the middle stage, the temperature is increased to a dry-bulb temperature of 40±0.5℃ and a wet-bulb temperature of 38±0.5℃; and in the later stage, the temperature is increased to a dry-bulb temperature of 42±0.5℃ and a wet-bulb temperature of 37±0.5℃. In step S402, the initial temperature is increased to a dry-bulb temperature of 47±0.5℃ while the wet-bulb temperature remains at 37±0.5℃; in the later stage, the temperature is increased to 54±0.5℃ while the wet-bulb temperature remains at 39±0.5℃. In step S403, the dry-bulb temperature is increased to 65±1℃ and the wet-bulb temperature is increased to 42±1℃. The temperature and humidity parameters ensure that the yellowing and water loss of the tobacco leaves are coordinated during the curing process, which is commonly referred to as "synchronous yellowing and softening." The more coordinated the yellowing and water loss of the tobacco leaves, the higher the curing quality. This temperature control scheme ensures the "synchronous yellowing and softening" of the tobacco leaves.

[0041] In this embodiment, the heating rate in step S401 is 1℃ / h, the heating rate in step S402 is 0.3℃ / h, and the heating rate in step S403 is 1℃ / h.

[0042] The existing methods for harvesting and curing tobacco leaves with 4-6 leaves and other treatments with stem lengths were compared with the methods in the embodiments of this application. The comparisons were made in five aspects: grade structure of the cured tobacco leaves, appearance quality, chemical composition harmony, sensory evaluation quality, and harvesting and curing efficiency. The comparison results are shown in Tables 1 to 5 below:

[0043] Table 1. Economic characteristics of upper tobacco leaves after curing with different stem lengths.

[0044]

[0045] Table 2 Appearance quality of upper tobacco leaves after curing with different stem lengths

[0046]

[0047] Table 3. Content of main chemical components in the upper part of tobacco leaves after curing with different stem lengths.

[0048]

[0049]

[0050] Table 4 Sensory evaluation of the upper tobacco leaves after curing with different stem lengths

[0051]

[0052] Table 5. Analysis of the economic benefits of harvesting and roasting single-stem plants.

[0053]

[0054]

[0055] As can be seen from Tables 1-4 above, in terms of the grade structure, appearance quality, chemical composition coordination, and sensory evaluation quality of the cured tobacco leaves, the cured tobacco leaves with 1cm stem are superior to those of the traditional 4-6 leaf cured tobacco leaves with stem and other cured tobacco leaves with stem lengths. As can be seen from Table 5, in terms of the efficiency of the curing process, the labor, fuel, and curing time required for the 1cm stem cured tobacco leaf curing technology are significantly reduced.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A simplified method for harvesting and curing single tobacco leaves with stems from the upper part of flue-cured tobacco, characterized in that, Includes the following steps: S1. Harvesting: When the upper tobacco leaves reach maturity, cut the tobacco leaves and stems off the tobacco plant one by one, keeping each tobacco leaf with 1-2 cm of the lower stem attached. S2. Binding / Hanging Tobacco: Use a rope to bind / hang tobacco leaves with short stems on both sides of the tobacco pole in a figure-eight pattern. Place the bound / hanged tobacco leaves in a shady place. S3. Loading tobacco: Transfer all the tied / hanging tobacco poles into the curing room and arrange them in an orderly manner according to a certain arrangement method; S4. Baking: Baking is carried out using a high-humidity yellowing and medium-humidity withering and color-fixing baking process; The baking process for high-humidity yellowing and medium-humidity withering and color fixing includes the following steps: S401, Yellowing stage: After the curing barn is filled with tobacco, it is ignited immediately. The temperature inside the curing barn rises and the tobacco leaves are cured until they turn 30-40% yellow. The temperature is maintained for 10-14 hours. After the tobacco leaves start to sweat noticeably, they begin to release moisture. The temperature is raised to a certain level and the tobacco leaves are cured until they turn 70-80% yellow. The temperature is maintained for 18-24 hours. The tobacco leaves become soft and collapse. The temperature is raised to a certain level and the tobacco leaves in the high-temperature greenhouse turn 90-100% yellow. The temperature is maintained for 14-22 hours. The tobacco leaves in the high-temperature greenhouse have hooked tips and curled edges, and the color of the tobacco leaves reaches the point of yellow leaves with green veins. S402, Color Fixing Period: Baking until the tobacco leaves in the low-temperature greenhouse turn yellow (9-10% yellow), maintaining the temperature for 10-16 hours, the tips and edges of the tobacco leaves curl, and the color of the tobacco leaves reaches yellow leaves with green veins. Continue to raise the temperature to a certain level and bake until the tobacco leaves are yellow leaves with white veins. Generally, maintain the temperature for 16-20 hours. Continue to raise the temperature to a certain level and bake until the tobacco leaves are basically completely dry, the main vein is more than one-third dry, and the tobacco leaves are in a large rolled state. Maintain the temperature for 12-14 hours. S403, Drying stage: Continue to raise the temperature to 65±1℃, maintain the temperature for 18 to 24 hours, and stop baking when the main vein of the tobacco leaves is completely dry. In step S401, the initial temperature is raised to a dry-bulb temperature of 38±0.5℃ and a wet-bulb temperature of 37±0.5℃; the intermediate temperature is raised to a dry-bulb temperature of 40±0.5℃ and a wet-bulb temperature of 38±0.5℃; and the final temperature is raised to a dry-bulb temperature of 42±0.5℃ and a wet-bulb temperature of 37±0.5℃. In step S402, the temperature initially rises to a dry-bulb temperature of 47±0.5℃ while the wet-bulb temperature remains at 37±0.5℃, and later the temperature rises to 54±0.5℃ while the wet-bulb temperature remains at 39±0.5℃. In step S403, the wet-bulb temperature is raised to 42±1℃.

2. The simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant according to claim 1, characterized in that, Steps S1 to S3 are completed within one day, and the baking is carried out on the same day.

3. The simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant according to claim 1, characterized in that, In step S1, the upper tobacco leaves reach maturity as follows: the basic color of the tobacco leaves is yellow, the leaf surface is fully yellowed, the main vein turns white, the lateral veins are basically all white, the leaf auricles are light yellow or have obvious yellow spots, the leaf tips droop, the leaf edges are wrinkled, the angle between the stem and leaves is significantly increased, and the maturity spots are obvious.

4. The simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant according to claim 1, characterized in that, In step S2, each tobacco wicker pole has 150-170 tobacco leaves. The tobacco wicker pole must be fully tied / hung, with 4-6cm of empty pole left at both ends. When tying / hanging the tobacco leaves, avoid damaging the leaves by friction with the ground.

5. The simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant according to claim 1, characterized in that, In step S3, when transferring the tobacco rods into the curing barn, starting from the partition wall of the heating chamber, tobacco is loaded simultaneously and alternately from the inside out, with the upper, middle and lower layers staggered. The tobacco rods on the same layer are evenly distributed, and the curing barn must be filled completely without leaving any gaps.

6. The simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant according to claim 5, characterized in that, In step S3, the amount of tobacco loaded per kang (heated brick bed) is 300-340 sticks.

7. The simplified method for harvesting and curing single tobacco leaves with stems from the upper part of the flue-cured tobacco plant according to claim 1, characterized in that, In step S3, tobacco leaves of the same variety and with similar overall quality should be placed in the same curing barn, without mixing them. The most representative tobacco leaves should be placed at the observation window of the curing barn to facilitate monitoring the changes in the tobacco leaves.

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