Method for baking upper leaves with stems suitable for sweet and sweet tobacco

Abstract

The invention discloses a method for baking upper leaves with stems suitable for sweet and sweet tobacco. According to the baking method, field curing, stem cutting, tobacco weaving and loading, baking and post-baking treatment are carried out on tobacco leaves, cold air circulation is carried out before baking to provide a stable baking initial environment, and the free water content in the tobacco leaves is adjusted by accurately controlling the temperature rising speed, the temperature and humidity and the temperature stabilizing time of all stages, so that the tobacco leaves achieve the optimal effect in all the stages. After curing, the leaves are cut off from main stems, excessive moisture regaining is prevented, the tobacco leaves have better quality, and the prepared tobacco leaves are good and stable in appearance quality.

Description

Technical Field

[0001] The invention belongs to the technical field of flue-cured tobacco, and particularly relates to a method for baking upper leaves with stems suitable for fresh, sweet and fragrant tobacco. Background Art

[0002] At present, the upper leaves of flue-cured tobacco are mainly harvested by removing the stems. Although this method is easy to operate, the loss of water during the baking process can easily lead to uneven drying, which can easily cause the tobacco leaves to become green or black, and directly affect the overall quality of the tobacco leaves. In addition, the upper tobacco leaves after being harvested by removing the stems lack sufficient support, which can easily cause the tobacco leaves to pile up tightly in the baking room and cause poor ventilation, further affecting the baking effect and resulting in a decline in the quality of the tobacco leaves.

[0003] In response to the above problems, Hubei, Yunnan, Sichuan and other places have developed stemmed harvesting and baking technology, but the stemmed harvesting and baking technology has many key points and the process is relatively complicated; the growth and development of tobacco is mainly affected by ecological factors such as light, temperature, moisture, soil, etc., which makes the appearance quality and internal quality of flue-cured tobacco vary greatly. Experiments have found that there are significant differences in the flavor of tobacco leaves in different regions. The fresh and sweet sweet tobacco leaves in Fujian and Guangdong regions directly adopt the stemmed baking technology of other regions, which will cause the appearance quality of the baked tobacco leaves to be unstable. Therefore, the present invention provides a method for baking the upper leaves with stems suitable for fresh and sweet sweet tobacco leaves. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that the above-mentioned prior art upper leaf baking technology with stems cannot be applied to the upper leaves with stems of fresh, sweet and fragrant tobacco, and there will be unstable appearance quality of the baked tobacco leaves, and to provide a method for baking upper leaves with stems suitable for fresh, sweet and fragrant tobacco.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for baking upper leaves with stems suitable for sweet and fragrant tobacco, comprising the following steps:

[0007] S1. Field curing: After the middle tobacco leaves are harvested, stop curing for 10 to 15 days. 7 to 10 days before the upper leaves are harvested, irrigate the tobacco field. The irrigation height is 1 / 4 to 1 / 3 of the height of the tobacco bed.

[0008] S2. Harvesting with stems: When the upper tobacco leaves are mature, harvest with stems 10 to 15 cm below the bottom leaves;

[0009] S3. Packing tobacco: Pack the stemmed tobacco leaves with cigarette clips and pack them;

[0010] S4. Baking:

[0011] S41 ventilates and circulates the loaded tobacco leaves for 30 minutes;

[0012] S42 operates at a dry-bulb temperature of 34-36°C for 4-6 hours, raises the dry-bulb temperature to 38-39°C at 2°C / h, maintains a steady temperature for 12-14 hours, and controls the wet-bulb temperature at 36-37°C;

[0013] S43 raises the dry bulb temperature to 40-41°C at 2°C / h, controls the wet bulb temperature at 37-38°C, and maintains the temperature steady for 18 hours;

[0014] S44 raises the dry bulb temperature to 42-43°C at 2°C / h, controls the wet bulb temperature at 38-39°C, and maintains the temperature for 16-20 hours;

[0015] S45 raises the dry bulb temperature to 44-46°C at 2°C / h, controls the wet bulb temperature at 38-39°C, and maintains the temperature for 8-12 hours;

[0016] Continue to raise the dry-bulb temperature to 47-48°C at 2°C / h, and control the wet-bulb temperature at 38-39°C, and keep it stable for 16-20 hours;

[0017] Continue to raise the dry bulb temperature to 50-52°C at 2°C / h, and control the wet bulb temperature at 38-39°C, and keep it stable for 4-10 hours;

[0018] Continue to raise the dry bulb temperature to 53-54°C at 2°C / h, control the wet bulb temperature at 40°C, and keep it stable for 12-16 hours;

[0019] S46 raises the dry bulb temperature to 60-62°C at 1°C / 1h, controls the wet bulb temperature at 41°C, and keeps the temperature steady for 4-6 hours;

[0020] Continue to raise the dry-bulb temperature to 66-68°C at 1°C / h, and control the wet-bulb temperature at 41-42°C, and keep it stable for 14-18 hours;

[0021] S5. Post-baking treatment: Stop the fire and allow the tobacco leaves to recover naturally. Cut the leaves off the main stem after baking.

[0022] In the above scheme, the moisture content of tobacco leaves is increased by irrigation during the field ripening stage, combined with the use of tobacco clips to clamp the tobacco, and ventilation circulation before ignition to create a stable initial environment for baking, which can effectively prevent the leaves from sticking together; adopt appropriate baking technology, accurately adjust the baking temperature and time, and adjust the free water content in the tobacco leaves to achieve the best effect at each stage; after baking, the leaves are cut off from the main stem to prevent excessive moisture resurgence, so that the tobacco leaves have better quality.

[0023] It should be noted that the upper leaves with stems of the sweet and fragrant tobacco described in the present invention are mainly distributed in Meizhou, Shaoguan, Guangdong and Longyan, Fujian.

[0024] Furthermore, when the leaves are harvested with stems, the cross section of the petiole is cut into an inclined surface.

[0025] Specifically, the stem-cutting and harvesting is carried out in the morning in a dewy state.

[0026] Furthermore, the cigarette arrangement and packing process comprises the following specific steps:

[0027] Use smoke clips to clamp smoke, and control the smoke quantity in each clip to 13-14kg. The smoke quantity in each curing room is controlled within 330 clips.

[0028] In some preferred embodiments, tobacco leaves of similar overall quality are loaded in the same curing barn, and tobacco plants with higher maturity, fewer leaves or shorter leaves are selected in the high-temperature layer.

[0029] In some preferred specific embodiments, step S41 is to close the door of the tobacco room and the cold air inlet door after the tobacco leaves are loaded according to S3, and turn on the circulating fan to circulate the air in the tobacco loading room for about 30 minutes. This can create a stable initial environment for baking, and can effectively prevent problems caused by poor ventilation due to leaf adhesion, such as the problem of steaming tobacco leaves after baking.

[0030] In some preferred specific embodiments, in step S42, the dry bulb temperature is 34-36°C and the operation is carried out for 4-6 hours until the tobacco leaves turn 30% yellow and the leaf tips turn yellow by about 10 cm; the fan operating speed is 960-1440 r / min; more preferably, the operation time is 4.5-5.5 hours.

[0031] In some preferred specific embodiments, in step S43, the temperature is maintained at a constant level for 18 hours until the tobacco leaves in the high and medium temperature layers turn yellow, leaving only a small amount of green on the main veins and the base of the leaves; the fan operating speed is 960-1440 r / min.

[0032] In some preferred specific embodiments, in step S44, the temperature is maintained at a constant temperature for 16 to 20 hours until the tobacco leaves in the entire tobacco house turn completely yellow, with the yellow leaves having slightly green veins, the leaves withering and collapsing, the main veins becoming soft, and the tobacco leaves losing water by 35±1%; the fan operating speed is 1440 r / min; more preferably, the temperature stabilization time is 17 to 18 hours.

[0033] In some preferred specific embodiments, in step S45, the temperature is maintained at a constant temperature for 8 to 12 hours until the base of the leaves turns yellow, no green remains, the tobacco leaves are in a curled state, and the water loss of the tobacco leaves is 40±1%; the fan operating speed is 1440r / min; more preferably, the temperature stabilization time is 9 to 11 hours.

[0034] In some preferred specific embodiments, in step S45, the temperature is maintained at a constant temperature for 16 to 20 hours until the main veins of tobacco leaves in the whole tobacco house turn pale and no green remains on the main veins, the leaves reach the small roll, and the water loss of tobacco leaves is 50±1%; the fan operating speed is 1440r / min; more preferably, the temperature stabilization time is 17 to 19 hours.

[0035] In some preferred embodiments, in step S45, the temperature is maintained at a constant temperature for 4 to 10 hours to allow the tobacco leaves to further curl and lose water, with a water loss of 60±1%; the fan operating speed is 1440 r / min; more preferably, the temperature stabilization time is 5 to 8 hours.

[0036] In some preferred specific embodiments, in step S45, the temperature is maintained at a constant temperature for 12 to 16 hours until the tobacco leaves in the entire tobacco room are dry and reach a fully curled large roll state, the tobacco leaves lose water by 70 to 80%, and the fan operates at a speed of 1440 r / min; more preferably, the temperature stabilization time is 13 to 15 hours.

[0037] In some preferred embodiments, in step S46, the temperature is maintained at a constant temperature for 4 to 6 hours until the main vein is 2 / 3 dry, and only 10 to 15 cm of the leaf base is left dry; the fan speed is 960 r / min; more preferably, the temperature stabilization time is 4.5 to 5.5 hours.

[0038] In some preferred specific embodiments, in step S46, the temperature is maintained at a constant temperature for 14 to 18 hours until the main veins of the tobacco leaves in the whole room are dry and turn purple, and the water loss of the tobacco leaves is 93±1%; the fan operating speed is 960r / min; more preferably, the temperature stabilization time is 15 to 17 hours.

[0039] In some preferred embodiments, in step S5, the leaves are cut from the main stem when the leaves are rehydrated to a moisture content of 14-15%.

[0040] The present invention also provides a sweet and fragrant tobacco leaf, which is prepared by the above baking method. Preferably, the sweet and fragrant tobacco leaf described in the present application is selected from tobacco leaves produced in Fujian or Guangdong. More preferably, it is tobacco leaves produced in Meizhou, Guangdong.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The invention provides a method for baking upper leaves with stems suitable for sweet and refreshing tobacco, wherein water is irrigated in the field curing stage to increase the moisture content of the tobacco leaves, cold air circulation is performed before ignition to create a stable initial environment for baking, the temperature and time in the baking process are adjusted to control the free water content in the tobacco leaves, and the leaves are cut off from the main stems after moisture resorption after baking to prevent excessive moisture resorption, thereby ensuring the quality of the tobacco leaves. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with specific examples, which are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0044] The test varieties are the main varieties in the Meizhou production area of ​​Guangdong. Tobacco fields with full development, balanced nutrition, open tops, and uniform and continuous growth are selected as the test materials for this application.

[0045] Example 1

[0046] A method for baking upper leaves with stems suitable for sweet and fragrant tobacco, comprising the following steps:

[0047] S1. Field curing: After the middle tobacco leaves are harvested, stop curing for 10 days. 7 days before the upper 4 to 6 leaves are harvested, irrigate the tobacco field. The irrigation height is 1 / 3 of the tobacco bed height.

[0048] S2. Harvesting with stems: When the upper leaves are mature (the top two leaves are 80% yellow), cut them 10 to 15 cm below the bottom leaf at a 45-degree angle to complete the harvesting with stems;

[0049] S3. Packing and loading tobacco: Use tobacco clips to clip the stemmed tobacco leaves, and control the weight of each clip to 13kg. Limit the hanging and loading of tobacco leaves, and load 3-16 clips in each flue-curing room. Load tobacco leaves of similar overall quality in the same flue-curing room. Select tobacco plants with higher maturity, fewer leaves or shorter leaves in the high-temperature layer. The tobacco leaves harvested on the same day are loaded and carried out on the same day for subsequent processes.

[0050] S4. Baking:

[0051] After the tobacco leaves are loaded in S41 according to S3, close the door of the drying room and the cold air inlet door, turn on the circulating fan, and circulate the air in the tobacco loading room for about 30 minutes to create a stable initial environment for baking and prevent the problem of poor ventilation caused by the adhesion of leaves;

[0052] S42 After completing step S41, start the circulating fan at 960r / min, run it at a dry bulb temperature of 36°C for 5 hours until the tobacco leaves turn 30% yellow and the leaf tips turn yellow by 10cm, then raise the dry bulb temperature to 38°C at a rate of 1°C per 2 hours, stabilize it for 14 hours, control the wet bulb temperature at 36°C, and run the fan at a speed of 960r / min;

[0053] S43 continues to raise the dry bulb temperature to 40℃ at a rate of 1℃ every 2 hours, and the wet bulb temperature is controlled at 37℃. The temperature is kept stable for about 18 hours until the tobacco leaves in the middle and high mesosphere layers turn yellow until the leaves are almost completely yellow, with only a small amount of green on the main veins and the base of the leaves. The tobacco leaves turn 70% yellow, and the fan runs at a speed of 1440r / min.

[0054] S44 continues to raise the dry bulb temperature to 42℃ at a rate of 1℃ every 2 hours, and the wet bulb temperature is controlled at 38℃, and the temperature is kept stable for 18 hours to ensure that the tobacco leaves in the whole tobacco room are completely yellow, with yellow leaves and slightly green veins, withered leaves and collapsed frames, main veins becoming soft, and the water loss of tobacco leaves is 35%. The fan running speed is 1440r / min;

[0055] S45 continues to raise the dry bulb temperature to 44°C at a rate of 1°C every 2 hours, and the wet bulb temperature is controlled at 38°C. The temperature is kept stable for 10 hours until the base of the leaves turns yellow without any residual green color, the tobacco leaves are curled at the tip, the water loss of the tobacco leaves is 40%, and the fan running speed is 1440r / min;

[0056] Continue to raise the dry bulb temperature to 48°C at a rate of 1°C every 2 hours, control the wet bulb temperature at 38°C, and keep the temperature steady for 18 hours until the main veins of all tobacco leaves in the room turn green and white, no green remains on the main veins, the leaves reach the small roll, the water loss of tobacco leaves is 50%, and the fan running speed is 1440r / min;

[0057] Continue to raise the dry bulb temperature to 50°C at a rate of 1°C every 2 hours, control the wet bulb temperature at 38°C, and keep the temperature steady for 6 hours to allow the tobacco leaves to further curl and lose water, with a water loss of 60%, and the fan running speed is 1440r / min;

[0058] Continue to raise the dry bulb temperature to 54°C at a rate of 1°C every 2 hours, control the wet bulb temperature at 40°C, and keep the temperature steady for 16 hours until the tobacco leaves in the whole tobacco room are dry and reach the state of full curling and large rolls, with the water loss of tobacco leaves being 70-80%, and the fan running speed is 1440r / min;

[0059] S46 continues to raise the dry bulb temperature to 60℃ at a rate of 1℃ per hour, and the wet bulb temperature is controlled at 41℃. The temperature is kept stable for 6 hours until the main vein is 2 / 3 dry, and only 10-15cm of the leaf base is not dry. The fan runs at a speed of 960r / min.

[0060] Continue to raise the dry bulb temperature to 67°C at a rate of 1°C per hour, control the wet bulb temperature at 41°C, and keep the temperature steady for 16 hours until the main veins of the tobacco leaves in the whole room are dry and turn purple, and the water loss of the tobacco leaves is 94%; the fan running speed is 960r / min;

[0061] S5. Post-curing treatment: After curing, stop the fire and allow the tobacco leaves to naturally rehydrate to a moisture content of 15%. After curing, cut the leaves from the main stems and store them separately in piles and bundles.

[0062] Example 2

[0063] A method for baking upper leaves with stems suitable for sweet and fragrant tobacco, comprising the following steps:

[0064] S1. Field curing: After the middle tobacco leaves are harvested, stop curing for 13 days. 9 days before the upper 4 to 6 leaves are harvested, irrigate the tobacco field. The irrigation height is 1 / 4 of the tobacco bed height.

[0065] S2. Harvesting with stems: When the upper leaves are mature (the top two leaves are 80% yellow), cut them 10 to 15 cm below the bottom leaf at a 45-degree angle to complete the harvesting with stems;

[0066] S3. Packing and loading tobacco: Use tobacco clips to clip the stemmed tobacco leaves, and control the weight of each clip to 13kg. Limit the hanging and loading of tobacco leaves, and load 324 clips in each flue-curing room. Load tobacco leaves of similar overall quality in the same flue-curing room. Select tobacco plants with higher maturity, fewer leaves or shorter leaves in the high-temperature layer. The tobacco leaves harvested on the same day are loaded and carried out on the same day for subsequent processes.

[0067] S4. Baking:

[0068] After the tobacco leaves are loaded in S41 according to S3, close the door of the drying room and the cold air inlet door, turn on the circulating fan, and circulate the air in the tobacco loading room for about 30 minutes to create a stable initial environment for baking and prevent the problem of poor ventilation caused by the adhesion of leaves;

[0069] S42 After completing step S41, start the circulating fan at 960r / min, run it at a dry bulb temperature of 36°C for 5 hours until the tobacco leaves turn 30% yellow and the leaf tips turn yellow by 10cm, then raise the dry bulb temperature to 38°C at a rate of 1°C per 2 hours, keep the temperature stable for 12 hours, control the wet bulb temperature at 37°C, and run the fan at a speed of 960r / min;

[0070] S43 continues to raise the dry bulb temperature to 40℃ at a rate of 1℃ every 2 hours, and the wet bulb temperature is controlled at 37℃. The temperature is kept stable for about 18 hours until the tobacco leaves in the middle and high mesosphere layers turn yellow until the leaves are almost completely yellow, with only a small amount of green on the main veins and the base of the leaves. The tobacco leaves turn 70% yellow, and the fan runs at a speed of 1440r / min.

[0071] S44 continues to raise the dry bulb temperature to 42℃ at a rate of 1℃ every 2 hours, and the wet bulb temperature is controlled at 38℃, and the temperature is kept stable for 16 hours to ensure that the tobacco leaves in the whole tobacco room are completely yellow, with yellow leaves and slightly green veins, withered leaves and collapsed frames, main veins becoming soft, and the water loss of tobacco leaves is 35%. The fan running speed is 1440r / min;

[0072] S45 continues to raise the dry bulb temperature to 44°C at a rate of 1°C every 2 hours, and the wet bulb temperature is controlled at 38°C. The temperature is kept stable for 8 hours until the base of the leaves turns yellow, no green remains, the tobacco leaves are curled, the water loss of the tobacco leaves is 40%, and the fan running speed is 1440r / min;

[0073] Continue to raise the dry bulb temperature to 48°C at a rate of 1°C every 2 hours, control the wet bulb temperature at 38°C, and keep the temperature steady for 16 hours until the main veins of all tobacco leaves in the room turn green and white, no green remains on the main veins, the leaves reach the small roll, the water loss of tobacco leaves is 50%, and the fan running speed is 1440r / min;

[0074] Continue to raise the dry bulb temperature to 51°C at a rate of 1°C every 2 hours, control the wet bulb temperature at 39°C, and keep the temperature steady for 4 hours to allow the tobacco leaves to further curl and lose water, with a water loss of 60%, and the fan running speed is 1440r / min;

[0075] Continue to raise the dry bulb temperature to 54°C at a rate of 1°C every 2 hours, control the wet bulb temperature at 40°C, and keep the temperature steady for 14 hours until the tobacco leaves in the whole tobacco room are dry and reach the state of full curling and large rolls, with the water loss of tobacco leaves being 70-80%, and the fan running speed is 1440r / min;

[0076] S46 continues to raise the dry bulb temperature to 60℃ at a rate of 1℃ per hour, and the wet bulb temperature is controlled at 41℃. The temperature is kept stable for 4 hours until the main vein is 2 / 3 dry, and only 10-15cm of the leaf base is not dry. The fan runs at a speed of 960r / min.

[0077] Continue to raise the dry bulb temperature to 68°C at a rate of 1°C per hour, control the wet bulb temperature at 42°C, and keep the temperature steady for 18 hours until the main veins of the tobacco leaves in the whole room are dry and turn purple, and the water loss of the tobacco leaves is 94%; the fan running speed is 960r / min;

[0078] S5. Post-curing treatment: After curing, stop the fire and allow the tobacco leaves to naturally rehydrate to a moisture content of 15%. After curing, cut the leaves from the main stems and store them separately in piles and bundles.

[0079] Comparative Example 1

[0080] The baking process is carried out by using the process in the prior art CN117643387A, which specifically includes the following steps:

[0081] S1. Harvesting with stems: When the upper leaves are mature (the top two leaves are 80% yellow), cut them 3 to 5 cm below the bottom leaf at a 45-degree angle to complete the harvest;

[0082] S2. Tobacco packing: Use tobacco clips to clamp the stemmed tobacco leaves, control the amount of tobacco in each clip to 17kg, limit the hanging and packing of tobacco, and each flue-curing room should be loaded with 250 clips;

[0083] S3. Baking:

[0084] S31 After the tobacco leaves are loaded according to S2, close the door of the curing room and the cold air inlet door, turn on the circulating fan, and circulate the air in the tobacco loading room for 120 minutes;

[0085] S32 After completing step S31, start the circulating fan at 960r / min, keep the dry bulb temperature at 36°C, control the wet bulb temperature at 36°C, and keep the temperature steady for 6 hours, so that the tips of the tobacco leaves turn yellow and soften; raise the dry bulb temperature to 38°C at a rate of 1°C per hour, control the wet bulb temperature at 37°C, and keep the temperature steady for 18 hours until the tobacco leaves turn 50% yellow, and the fan running speed is 960r / min;

[0086] S33 continues to raise the dry bulb temperature to 40℃ at a rate of 1℃ per hour, and the wet bulb temperature is controlled at 37℃. The temperature is kept stable for 14 hours until the tobacco leaves turn 70% yellow and the leaves wilt softly. The fan runs at a speed of 960r / min.

[0087] S34 continues to raise the dry bulb temperature to 42℃ at a rate of 1℃ per hour, and the wet bulb temperature is controlled at 37℃. Keep the temperature steady for 22 hours until the tobacco leaves turn 90% yellow, the veins of the yellow leaves are slightly green, and the main veins become soft.

[0088] S35 continues to raise the dry bulb temperature to 45°C at a rate of 1°C in 3 hours, and the wet bulb temperature is controlled at 37°C. The temperature is kept stable for 2 hours, and the fan speed is 1440r / min.

[0089] Continue to raise the dry bulb temperature to 48°C at a rate of 1°C every 3 hours, control the wet bulb temperature at 37°C, and keep the temperature steady for 7 hours until the tobacco leaves turn yellow and white and 1 / 3 of the leaves are dry. The fan speed is 1440r / min.

[0090] Continue to raise the dry bulb temperature to 50°C at a rate of 1°C per hour, control the wet bulb temperature at 38°C, keep the temperature steady for 6 hours, and the fan running speed is 1440r / min;

[0091] Continue to raise the dry bulb temperature to 54°C at a rate of 1°C per hour, control the wet bulb temperature at 38°C, and maintain the temperature for 12 hours until the tobacco leaf dryer fan runs at 960r / min.

[0092] S46 continues to raise the dry bulb temperature to 60℃ at a rate of 1℃ per hour, and the wet bulb temperature is controlled at 41℃. The temperature is kept stable for 6 hours until the main veins of the tobacco leaves turn purple-brown and the ribs are 1 / 2 dry. The fan runs at a speed of 960r / min.

[0093] Continue to raise the dry bulb temperature to 66°C at a rate of 1°C per hour, control the wet bulb temperature at 42°C, and keep the temperature steady for 22 hours until the tobacco stems are completely dry; the fan running speed is 960r / min;

[0094] S5. Post-curing treatment: After curing, stop the fire and allow the tobacco leaves to naturally rehydrate to a moisture content of 15%, then stack and bundle the tobacco leaves separately for storage.

[0095] Comparative Example 2

[0096] The baking is carried out using the process in the prior art CN 112273700A, with specific reference to Example 1 thereof.

[0097] Performance Testing

[0098] 1. Test Method

[0099] (1) Appearance quality evaluation: The tobacco leaves obtained by baking in the above-mentioned embodiments and comparative examples were taken as original samples for appearance quality evaluation, one clip of tobacco leaves from the middle and lower sheds on the left and right roads of the tobacco house were taken as the original samples for appearance quality evaluation. The original samples were fully mixed to balance the moisture content of the tobacco leaves. The moisture content was tested by a KH-115 special moisture detector. The equilibrium moisture content was 17±1%. 100 leaves were taken from each group of samples as evaluation samples. According to the flue-cured tobacco standard GB2635-1992, three team members (two technicians with the second-level tobacco grader qualification performed the evaluation, and one appraisal team leader was responsible for the result confirmation) quantitatively scored the color, maturity, leaf structure, identity, oil content, and chroma of the sample quality factors. See Table 1. The comprehensive score of appearance quality = (color × 0.3 + maturity × 0.25 + leaf structure × 0.15 + identity × 0.12 + oil content × 0.1 + chroma × 0.08) × 10.

[0100] Table 1 Standards for assigning values ​​to various factors of flue-cured tobacco appearance quality

[0101]

[0102] (2) Sensory quality evaluation: The samples were processed in the same way as the appearance quality evaluation, and 7 sensory assessors were assigned sensory quantitative scores according to the standards, see Table 2. The greater the concentration and strength, the higher the rating standard, and the better the quality characteristics of other indicators, the higher the score; the minimum scoring unit for each individual indicator is 0.5 points; concentration, strength, and fragrance are style characteristics and are not included in the calculation of the total score. Sensory quality score of the evaluation: Total score = (fragrance quality × 35% + fragrance volume × 25% + miscellaneous smell × 10% + irritation × 15% + aftertaste × 15%) × 10.

[0103] Table 2 Scoring standards for specific indicators of sensory evaluation of flue-cured tobacco smoking quality

[0104]

[0105]

[0106] 2. Experimental results

[0107] The test results of the embodiments and comparative examples are shown in Tables 3-4.

[0108] Table 3 Appearance quality of each embodiment and comparative example

[0109]

[0110] Table 4 Sensory evaluation quality scores of each embodiment and comparative example

[0111]

[0112] As can be seen from Tables 3 and 4, the tobacco leaves prepared by the method for baking the upper leaves with stems suitable for sweet and sweet tobacco described in this application show significant advantages in appearance quality and sensory evaluation quality. Specifically, through the full preparation of the field maturation stage, and the meticulous operation of the links such as cutting and harvesting with stems, weaving and packing tobacco, a solid foundation is laid for the subsequent baking process. During the baking process, the present application plans in detail the parameters from the yellowing, color setting, and dry tendon stages. The temperature, humidity, and temperature stabilization time of each stage are carefully set to adjust the moisture content in the tobacco leaves and promote the reasonable changes in the tissue structure of the tobacco leaves. It can be seen from the comparison of the embodiments and the comparative examples that the tobacco leaves of Examples 1 and 2 have obtained higher scores in appearance quality factors such as color, maturity, leaf structure, identity, oil content, and chroma, and the comprehensive score averages 74.53 points, showing good overall appearance quality, which fully verifies the effectiveness of the method in improving the appearance quality of tobacco leaves. In terms of sensory evaluation of smoking quality, the tobacco leaves of Example 1 and Example 2 performed well in terms of aroma quality, aroma quantity, miscellaneous smell, irritation and aftertaste, and the average sensory quality comprehensive score was 67 points, compared with 63 points of Comparative Example 1 and 62 points of Comparative Example 2, showing that the method also showed obvious advantages, with a significant improvement in aroma quality and aroma quantity, and a decrease in miscellaneous smell and irritation. These data fully demonstrate the effectiveness and superiority of the baking method provided in this application in improving the quality of the upper leaves of the stem of the sweet and sweet tobacco, and provide a practical tobacco baking technology solution for the sweet and sweet tobacco area, especially the Guangdong tobacco area.

[0113] The baking method of the upper leaves with stems in the prior art shows limitations in the baking effect data of the Guangdong tobacco area. From the perspective of appearance quality, although the tobacco leaves of Comparative Examples 1 and 2 also obtained certain scores in terms of color, maturity, leaf structure, etc., the comprehensive scores were only 72.25 and 72.90, which were lower than the average level of the embodiments of the present application. This shows that the prior art has shortcomings in improving the overall appearance quality and sensory quality of tobacco leaves of sweet and sweet tobacco, and it is also impossible to fully demonstrate the quality characteristics of tobacco leaves in the studied production area. In terms of sensory evaluation and smoking quality, although the scores of the tobacco leaves of Comparative Example 1 in key indicators such as aroma quality and aroma quantity are acceptable, the impurities are slightly increased compared with the embodiments, showing that the tobacco leaves are slightly lacking in aroma purity. At the same time, the irritation is also increased to a certain extent compared with the embodiments, indicating that the process parameters of Comparative Example 1 during the baking process may have an impact on the intrinsic quality of tobacco leaves. To sum up, the existing method of baking the upper leaves with stems has shortcomings in optimizing the appearance quality of tobacco leaves in the studied production area and improving the sensory quality, which does not meet the needs of the method effect provided by this application, further highlighting the technical advantages of this application in improving the quality of the upper leaves with stems of sweet and fragrant tobacco.

[0114] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for baking the upper leaves with stems of sweet and fragrant tobacco, characterized in that: The steps include: S1. Field curing: After the middle tobacco leaves are harvested, stop curing for 10 to 15 days. 7 to 10 days before the upper leaves are harvested, irrigate the tobacco field. The irrigation height is 1 / 4 to 1 / 3 of the height of the tobacco bed. S2. Harvesting with stems: When the upper tobacco leaves are mature, harvest with stems 10 to 15 cm below the bottom leaves; S3. Packing tobacco: Pack the stemmed tobacco leaves with cigarette clips and pack them; S4. Baking: S41 ventilates and circulates the loaded tobacco leaves for 30 minutes; S42 operates at a dry-bulb temperature of 34-36°C for 4-6 hours, raises the dry-bulb temperature to 38-39°C at 2°C / h, maintains a steady temperature for 12-14 hours, and controls the wet-bulb temperature at 36-37°C; S43 raises the dry bulb temperature to 40-41°C at 2°C / h, controls the wet bulb temperature at 37-38°C, and maintains the temperature steady for 18 hours; S44 raises the dry bulb temperature to 42-43°C at 2°C / h, controls the wet bulb temperature at 38-39°C, and maintains the temperature for 16-20 hours; S45 raises the dry bulb temperature to 44-46°C at 2°C / h, controls the wet bulb temperature at 38-39°C, and maintains the temperature for 8-12 hours; Continue to raise the dry-bulb temperature to 47-48°C at 2°C / h, and control the wet-bulb temperature at 38-39°C, and keep it stable for 16-20 hours; Continue to raise the dry-bulb temperature to 50-52°C at 2°C / h, and control the wet-bulb temperature at 38-39°C for 4-10 hours; Continue to raise the dry bulb temperature to 53-54°C at 2°C / h, control the wet bulb temperature at 40°C, and keep it stable for 12-16 hours; S46 raises the dry bulb temperature to 60-62°C at 1°C / 1h, controls the wet bulb temperature at 41°C, and keeps the temperature steady for 4-6 hours; Continue to raise the dry bulb temperature to 66-68°C at 1°C / h, and control the wet bulb temperature at 41-42°C, and keep it stable for 14-18 hours; S5. Post-baking treatment: Stop the fire and allow the tobacco leaves to recover naturally. Cut the leaves off the main stem after baking.

2. The method for baking the upper leaves with stems of sweet and fragrant tobacco according to claim 1, characterized in that: When harvesting with stems, the cross section of the petiole is cut into an inclined surface.

3. The method for baking the upper leaves with stems of the sweet and fragrant tobacco according to claim 1, characterized in that: The cigarette arrangement and packing comprises the following specific steps: Use smoke clips to clamp smoke, and control the amount of smoke in each clip to 13-14kg. The amount of smoke in each curing room is controlled within 330 clips.

4. The method for baking the upper leaves with stems of sweet and fragrant tobacco according to claim 1, characterized in that: In step S42, the dry bulb temperature is 34-36°C and the machine is operated for 4-6 hours until the tobacco leaves turn 30% yellow and the leaf tips turn 10 cm yellow; the fan operating speed is 960-1440 r / min.

5. The method for baking the upper leaves with stems of sweet and fragrant tobacco according to claim 1, characterized in that: In step S43, the temperature is kept constant for 18 hours until the tobacco leaves in the high and medium temperature layers turn yellow, leaving only a small amount of green on the main veins and the base of the leaves, and the tobacco leaves turn 70% to 80% yellow; the fan operating speed is 960 to 1440 r / min.

6. The method for baking the upper leaves with stems of sweet and fragrant tobacco according to claim 1, characterized in that: In step S44, the temperature is kept constant for 16 to 20 hours until the tobacco leaves in the whole tobacco house turn completely yellow, with the veins of the yellow leaves slightly green, the leaves wither and collapse, the main veins become soft, and the water loss of the tobacco leaves is 35±1%; the fan operating speed is 1440r / min.

7. The method for baking the upper leaves with stems of the sweet and fragrant tobacco according to claim 1, characterized in that: In step 45, the temperature is maintained for 8 to 12 hours until the base of the leaves turns yellow, no residual cyan remains, the leaves are in a curled state, and the water loss of the leaves is 40±1%; the fan runs at a speed of 1440 r / min; the temperature is maintained for 16 to 20 hours until the main veins of the tobacco leaves in the whole tobacco room fade and turn white, no residual cyan remains on the main veins, the leaves reach a small roll, and the water loss of the leaves is 50±1%; the fan runs at a speed of 1440 r / min; the temperature is maintained for 4 to 10 hours to make the tobacco leaves further curl and lose water, and the water loss is 60±1%; the fan runs at a speed of 1440 r / min; the temperature is maintained for 12 to 16 hours until the tobacco leaves in the whole tobacco room are dry and reach a fully curled large roll state, the water loss of the tobacco leaves is 70-80%, and the fan runs at a speed of 1440 r / min.

8. The method for baking the upper leaves with stems of sweet and fragrant tobacco according to claim 1, characterized in that: In step S46, the temperature is maintained at a constant temperature for 4 to 6 hours until the main vein is dried to 2 / 3, with only 10 to 15 cm of the leaf base remaining wet; the fan operating speed is 960 r / min; the temperature is maintained at a constant temperature for 14 to 18 hours until the main vein of all tobacco leaves in the room is dry and turns purple, and the water loss of the tobacco leaves is 93±1%; the fan operating speed is 960 r / min.

9. The method for baking the upper leaves with stems of sweet and fragrant tobacco according to claim 1, characterized in that: In step S5, the leaves are cut from the main stem when the leaves are rehydrated to a moisture content of 14-15%.

10. A sweet and fragrant tobacco leaf, characterized in that: It is prepared by the baking method according to any one of claims 1 to 9.

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