A picking and roasting method that highlights the sweet and refreshing aroma of Cuibi No. 1 tobacco leaves

Abstract

The invention discloses a harvesting and curing method that highlights the sweet and refreshing fragrance of Cui Bi No. 1 tobacco leaves, comprising: S1, harvesting: the maturity of the tobacco leaves is harvested lower than 10% of the conventional method; S2, loading on a bed: the tobacco leaves are braided into poles and then loaded into a dense curing room in a conventional manner, and a fan is turned on and operated for 2-3 hours; S3, baking: the temperature and humidity during the baking yellowing period and the corresponding yellowing degree of the tobacco leaves, the heating rate during the color fixing period and the temperature and humidity are adjusted; the present invention effectively improves the appearance quality of the tobacco leaves and the coordination of the chemical composition by adjusting the harvesting maturity and the supporting baking process, solves the problems of blue veins, green-yellow, smoothness and dustiness in the baking of CB-1 tobacco leaves, further highlights the sweet and refreshing fragrance of Fujian Cui Bi No. 1 tobacco leaves, and improves the industrial availability and economic value of the tobacco leaves.

Description

Technical Field

[0001] The invention relates to a harvesting and curing method that highlights the fresh, sweet and fragrant style of Cui Bi No. 1 tobacco leaves, and belongs to the technical field of tobacco harvesting and curing. Background Art

[0002] Aroma refers to the overall aroma type or tone exhibited by tobacco smoke during smoking. Tracing the process of tobacco aroma formation reveals that under the unique ecological conditions of the production area, certain metabolic pathways in the tobacco leaf are specifically expressed, resulting in differentiated metabolites in mature, harvested fresh tobacco leaves and chemical composition content in flue-cured tobacco leaves, ultimately presenting a unique sensory experience. With in-depth research on the aroma characteristics of flue-cured tobacco leaves nationwide, the 2017 "Notice on the Aroma Zoning of Flue-cured Tobacco Leaves" categorized the country's flue-cured tobacco leaves into eight major aroma types: the Southwest Plateau Ecological Region (Light Sweet Aroma), the Guizhou-Guangxi Mountain Ecological Region (Honey Sweet Aroma), the Wuling-Qinba Ecological Region (Mellow Sweet Aroma), the Huanghuai Plain Ecological Region (Scorched Sweet Aroma), the Nanling Hilly Ecological Region (Scorched Sweet Mellow Sweet Aroma), the Wuyi Hilly Ecological Region (Light Sweet Aroma), the Yimeng Hilly Ecological Region (Honey Sweet Caramel Aroma), and the Northeast Plain Ecological Region (Wooden Fragrant Honey Sweet Aroma). This transcends the traditional three aroma types of strong, medium, and light.

[0003] Cui Bi No. 1 (CB-1), one of the only two remaining specialty flue-cured tobacco varieties in the country, is only distributed in the tobacco-growing areas of Fujian. It has a refreshing, elegant, and mellow aroma and is a typical sweet-sweet variety with excellent quality, strong industrial compatibility and usability, and is deeply favored by cigarette industry formula developers. However, before the "Eight Flavor Types of Flue-cured Tobacco" were divided in my country's tobacco-growing areas, Fujian tobacco areas were divided into light-fragrance style production areas, and all research and production technology development were centered around the development of the light-fragrance style. For example, the patent document (CN102106598B) discloses an intensive baking process for the specialty flue-cured tobacco variety Cui Bi No. 1. This solution divides the baking stage into five stages, namely, yellowing is divided into two stages, color setting is divided into two stages, and dry tendons are divided into one stage. Among them: the yellowing period is extended by 12-24 hours during baking, the main yellowing temperature is increased by 1-2°C, and the wet-bulb temperature in the late yellowing and early color setting stages is reduced by 2-3°C, making the baking process conditions more precise, in order to solve the problems of unsatisfactory baking quality, excessive green tendons, and ash smoke in traditional baking processes, and fully demonstrate the light-fragrance characteristic quality style of Cui Bi No. 1.

[0004] With Fujian tobacco growing in China repositioning itself as a region with a sweet and clear flavor profile, traditional flue-curing processes are failing to effectively enhance the sweet and clear flavor profile of CB-1 tobacco leaves. Consequently, researchers have conducted extensive research on the CB-1 variety. For example, patent document (CN111615925A) discloses a harvesting method that highlights the quality and style of Cui Bi No. 1's upper tobacco leaves. This method harvests six fully mature leaves of the upper tobacco leaves at once to increase the total sugar and reducing sugar content, thereby balancing the total nitrogen and nicotine content. This significantly improves the balance of chemical composition and enhances sensory quality. However, this method only addresses the harvesting of tobacco leaves. For tobacco leaf industrial usability, tobacco leaf quality is fundamental, but achieving a more representative flavor profile through flue-curing is even more crucial. Due to the relatively poor flue-curing characteristics of the CB-1 variety and its difficulty in flue-curing, the problem of high levels of greenish-yellow, smooth, and ash-covered tobacco leaves after flue-curing remains unresolved in actual production. This results in a low grade structure and a poorly representative sweet and clear flavor profile. To this day, the industry still holds the perception that this variety is "neither greenish-yellow, nor ash-covered, nor Cui Bi." It is necessary to conduct research and improve this. Summary of the Invention

[0005] Based on the above, the present invention provides a harvesting and roasting method that highlights the fresh, sweet and fragrant style of Cui Bi No. 1 tobacco leaves, which can further solve the problems of blue veins, green and yellow, smoothness and dustiness that occur during the roasting of CB-1 tobacco leaves, so that CB-1 tobacco leaves can obtain a more typical fresh, sweet and fragrant style.

[0006] The technical solution of the present invention is: a method for harvesting and roasting tobacco leaves that highlights the sweet and refreshing aroma of Cuibi No. 1 tobacco leaves, comprising:

[0007] S1, Harvesting: The tobacco leaves are harvested at a maturity lower than 10% of the normal maturity;

[0008] S2, Installing the kang: After the tobacco leaves are braided into poles, they are placed in the dense curing room in the conventional way, and the fan is turned on and runs for 2-3 hours;

[0009] S3, Bake: Bake as follows:

[0010] S31, ignite, raise the temperature to 40±0.5℃ dry bulb at 0.8-1.0℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer turn 50%-60% yellow. The fan mainly runs at low speed. Every 4 hours, the fan runs at high speed or high frequency for 30-60 minutes;

[0011] S32, raise the temperature to 41±0.5℃ dry bulb at 0.25-0.3℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer turn 70% to 80% yellow and become soft and collapse on the rack. The fan mainly operates at medium speed or medium frequency. Every 6 hours, the fan runs at high speed for 30-60 minutes;

[0012] S33: Raise the temperature at 0.2-0.25°C / h to a dry-bulb temperature of 42±0.5°C, maintain a wet-bulb temperature of 39±0.5°C, and stabilize the temperature until the tobacco leaves in the high-temperature layer turn 80% to 90% yellow. Then adjust the wet-bulb temperature to 38±0.5°C and stabilize the temperature until the tobacco leaves in the high-temperature layer turn 90% to 10% yellow, i.e., yellow leaves with blue veins, completely yellow leaves with only the main vein and 2-3 pairs of lateral veins at the base green, and the tobacco leaves lose water to the point of curling. The fan is running at high speed.

[0013] S34, raise the temperature to 44±0.5℃ dry bulb at 0.2-0.25℃ / h, maintain wet bulb at 37±0.5℃, and stabilize the temperature until the tobacco leaves in the low temperature layer turn 90% to 10% yellow, i.e. yellow leaves with blue veins, completely yellow leaves with only the main vein and 2-3 pairs of side veins at the base green, and the tobacco leaves lose water to the point of curling, and the fan runs at high speed;

[0014] S35, raise the temperature to 46±0.5℃ dry bulb at 0.25-0.3℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer are completely yellow, that is, yellow leaves and white veins, the leaves are completely yellow, all the veins are completely white, the tobacco leaves are 2 / 3 dry, and the appearance is small rolls. The fan speed is running at medium speed;

[0015] S36, raise the temperature to 48±0.5℃ dry bulb at 0.25-0.3℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the tobacco leaves in the low temperature layer are completely yellow, that is, yellow leaves and white veins, the leaves are completely yellow, all the veins are completely white, the tobacco leaves are 2 / 3 dry, and the appearance is small rolls. The fan speed is operated at medium speed;

[0016] S37, raise the temperature to 50±0.5℃ dry bulb at 0.3-0.5℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the high temperature layer and the middle layer of tobacco leaves are 4 / 5 dry and the appearance is large rolls. The fan speed is operated at medium speed;

[0017] S38, raise the temperature to 54±0.5℃ dry bulb at 0.3-0.5℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the flue-curing room are completely dry except for the main veins, and the main veins are more than 1 / 3 dry, that is, the whole flue-cured tobacco leaves have the appearance of large rolls, and the fan speed is operated at medium speed;

[0018] S39, increase the temperature at 0.5-1℃ / h to 60±0.5℃ dry bulb, maintain 40±0.5℃ wet bulb, run for 8-10 hours, and run the fan at medium speed;

[0019] S40, increase the temperature to 65±0.5℃ dry bulb at 0.5-1℃ / h, maintain the wet bulb at 41±0.5℃, and run until the main vein of the whole flue-cured tobacco leaves are completely dry. The fan speed runs at low speed.

[0020] Preferably, in step S1, tobacco leaves from various parts are harvested according to the following standards: 50% of the lower leaves are yellow-green, and the main veins turn green and begin to turn white; 70% of the middle leaves are yellow-green, and 1 / 2 of the main veins turn white; 80% of the upper leaves are yellow-green, and 2 / 3 of the main veins turn white and shiny.

[0021] Preferably, the high speed range of the fan is 1300-1500 rpm, the medium speed range is 940-980 rpm, and the low speed range is 700-750 rpm.

[0022] Preferably, the high speed of the fan is 1440 rpm, the medium speed is 960 rpm, and the low speed is 720 rpm.

[0023] The research of the present invention illustrates that: through the study of the baking characteristics of CB-1 tobacco leaves of different maturity, the applicant found that as the maturity of CB-1 tobacco leaves decreases, the yellowing and browning rates thereof decrease, especially the onset of browning is significantly delayed, which will cause a delay in the occurrence of tobacco leaves becoming dusty. At this time, if a conventional baking process (patent announcement number: CN102106598 B) is adopted, the yellowing time will be too long, causing the tobacco leaves to begin to turn brown (become dusty) before they have completed yellowing. In response to this problem, the technical approach adopted by the applicant is to increase the yellowing rate during the baking process, shorten the yellowing time, and complete the yellowing before the tobacco leaves begin to brown. In order to achieve this effect, it is necessary to increase the temperature of the tobacco leaves themselves, that is, to increase the temperature of the dry bulb and the wet bulb at the same time, thereby increasing the activity of various hydrolases inside the tobacco leaves, promoting the yellowing of the tobacco leaves and the decomposition of macromolecular substances, and thus improving the quality of the tobacco leaves. Specifically, during the yellowing period, the present invention focuses on the temperature of the tobacco leaves themselves (i.e., the wet-bulb temperature, which can basically represent the temperature of the tobacco leaves during the yellowing period). The wet-bulb is maintained at 39±0.5°C in the two key stages S31 and S32 and the pre-stage of S33. The purpose of raising the dry-bulb temperature in the S32 stage is to expand the dry-bulb temperature difference, which is beneficial to the water loss of the tobacco leaves and promotes the coordination of water loss and yellowing of the tobacco leaves. This is different from the previous technology of simply lowering the wet-bulb temperature to achieve water loss of the tobacco leaves. Although simply lowering the wet-bulb temperature can accelerate the water loss of the tobacco leaves, it also reduces the temperature of the tobacco leaves themselves, which is not conducive to the formation of good quality of the tobacco leaves during the baking process. During the S33 stage, a "one-step, two-step" technique—one dry-bulb temperature corresponds to two wet-bulb temperatures—is employed. This aims to reduce leaf respiration by lowering the wet-bulb temperature (leaf temperature) near the end of the yellowing phase, thereby preventing excessive consumption of small molecules derived from the decomposition of macromolecules. This, in turn, widens the dry-bulb temperature difference, increasing the degree of leaf water loss and wilting, promoting a coordinated dehydration and yellowing process, and facilitating color fixation after the transition to hot-burning. At the end of the yellowing phase, some veins remain untouched. If the temperature is raised too quickly during the color fixation phase, the leaves will lose water too quickly, preventing the veins from yellowing. This will result in blue veins in the leaves after curing, severely reducing their quality. From the end of the yellowing phase to the color fixation phase, dry-bulb temperatures are set in 2°C steps. Observation of leaf changes is staggered between the upper and lower sheds, accommodating a 2°C temperature difference between the upper and lower sheds. This approach ensures consistent leaf quality throughout the flue-curing barn.

[0024] The beneficial effects of the present invention are as follows: the present invention adjusts the tobacco leaf harvesting maturity, the temperature and humidity during the yellowing period and the corresponding yellowing degree of the tobacco leaves, the heating rate and the temperature and humidity during the color fixing period in the prior art, thereby forming a technical solution including suitable harvesting maturity and a matching baking process, effectively improving the appearance quality of the tobacco leaves and the coordination of the chemical composition, solving the problems of blue veins, green-yellow, smoothness and dustiness in the baking of CB-1 tobacco leaves, further highlighting the sweet and refreshing style of Fujian Cuibi No. 1 tobacco leaves, and improving the industrial availability and economic value of the tobacco leaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Baking characteristics of lower leaves at different maturity levels in a dark box;

[0026] Figure 2 Baking characteristics of middle leaves of different maturity in a dark box;

[0027] Figure 3 Baking characteristics of upper leaves at different maturity levels in a dark box. DETAILED DESCRIPTION

[0028] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Index determination and methods:

[0030] Grade structure and appearance identification: Grading and weighing are carried out according to the national standard (GB2635-92), and the smoke rate and average price of the upper, middle and lower grades are calculated, and the economic characteristics are calculated; appearance evaluation is carried out according to the national standard (GB2635-92).

[0031] Main chemical components: total sugar and reducing sugar were determined using the YC / T159-2002 method; nicotine was determined using the YC / T160-2002 method; total nitrogen was determined using the YC / T161-2002 method; starch was determined using the YC / T216-2007 method; and protein was determined using the YC / T249-2008 method.

[0032] Sensory evaluation of smoking quality: evaluated by smoking experts according to the YC / T530-2015 method, including: style typicality, strength, concentration, aroma quality, aroma volume, permeability, miscellaneous smell, pungency, aftertaste, sweetness, burningness, and grayness.

[0033] The test varieties used in the following Examples 1 to 3 and Comparative Examples 1 to 3 were all CB-1 (standard medium-sized tobacco) varieties grown in the same field in the tobacco area of ​​Liancheng County, Longyan City. The tobacco leaves in the tobacco fields were managed according to the standardized production management of flue-cured tobacco, and the tobacco fields were uniform and cured in intensive curing rooms.

[0034] Example 1

[0035] A method for harvesting and roasting the lower leaves of Cuibi No. 1 tobacco to highlight its sweet and refreshing aroma, comprising:

[0036] S1, harvesting: The lower tobacco leaves are harvested when the leaf surface turns 50% yellow-green and the main veins begin to turn white;

[0037] S2, loading the kang: After the tobacco leaves are braided into poles, they are loaded into the dense curing room in the conventional way, and the fan is turned on and runs for 2.5 hours;

[0038] S3, Bake: Bake as follows:

[0039] S31, ignite, raise the temperature to 40±0.5℃ dry bulb at 0.8℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer turn 50% to 60% yellow. The fan is mainly operated at low speed. Every 4 hours, the fan is operated at 1440 rpm for 45 minutes;

[0040] S32, raise the temperature to 41±0.5℃ dry bulb at 0.25℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer turn 70% to 80% yellow and become soft and collapse on the rack. The fan mainly operates at medium speed or medium frequency. Every 6 hours, the fan runs at 1440 rpm for 45 minutes;

[0041] S33: Raise the temperature at 0.2°C / h to a dry-bulb temperature of 42±0.5°C, maintain a wet-bulb temperature of 39±0.5°C, and stabilize the temperature until the tobacco leaves in the high-temperature layer turn 80% to 90% yellow. Then adjust the wet-bulb temperature to 38±0.5°C and stabilize the temperature until the tobacco leaves in the high-temperature layer turn 90% to 10% yellow, i.e., yellow leaves with blue veins, completely yellow leaves with only the main vein and 2-3 pairs of lateral veins at the base green, and the tobacco leaves lose water to the point of curling. The fan is operated at 1440 rpm.

[0042] S34: Raise the temperature at 0.2°C / h to a dry-bulb temperature of 44±0.5°C, maintain a wet-bulb temperature of 37±0.5°C, and stabilize the temperature until the tobacco leaves in the low-temperature layer turn 90% to 10% yellow, i.e., yellow leaves with blue veins, and completely yellow leaves with only the main vein and 2-3 pairs of lateral veins at the base remaining green. The tobacco leaves lose water and reach the point of curling. The fan is operated at 1440 rpm.

[0043] S35: Raise the temperature at 0.25℃ / h to 46±0.5℃ dry bulb, maintain 38±0.5℃ wet bulb, and stabilize the temperature until the tobacco leaves in the high temperature layer are completely yellow, i.e. yellow leaves with white veins, all leaves are completely yellow, all veins are completely white, and the tobacco leaves are 2 / 3 dry and look like small rolls. The fan runs at 960 rpm.

[0044] S36, raise the temperature to 48±0.5℃ dry bulb at 0.25℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the tobacco leaves in the low temperature layer are completely yellow, that is, yellow leaves and white veins, the leaves are completely yellow, all the veins are completely white, the tobacco leaves are 2 / 3 dry, and the appearance is small rolls. The fan runs at 960 rpm;

[0045] S37, raise the temperature to 50±0.5℃ dry bulb at 0.3℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the high temperature layer and the middle layer of tobacco leaves are 4 / 5 dry and have the appearance of large rolls. The fan runs at 960 rpm;

[0046] In step S38, increase the temperature at 0.3°C / h to a dry-bulb temperature of 54±0.5°C, maintain a wet-bulb temperature of 39±0.5°C, and maintain the temperature until the tobacco leaves in the flue-curing room are completely dry except for the main veins, and the main veins are more than 1 / 3 dry, that is, the whole flue-cured tobacco leaves appear like large rolls. The fan is operated at 960 rpm.

[0047] S39, raise the temperature to 60±0.5℃ dry bulb at 0.5℃ / h, maintain the wet bulb at 40±0.5℃, run for 8-10 hours, and run the fan at 960 rpm;

[0048] S40, increase the temperature to 65±0.5℃ dry bulb at 0.5℃ / h, maintain the wet bulb at 41±0.5℃, and run until the main vein of the whole flue-cured tobacco leaves are completely dry. The fan runs at 720 rpm.

[0049] Example 2

[0050] A harvesting and curing method that highlights the sweet and refreshing flavor of the middle tobacco leaves of Cui Bi No. 1, which is different from Example 1 in that the middle tobacco leaves are harvested when 70% of the leaf surface is yellow-green and the main veins turn white.

[0051] Example 3

[0052] A harvesting and roasting method that highlights the sweet and refreshing aroma of Cui Bi No. 1 upper tobacco leaves is different from Example 1 in that the upper tobacco leaves are harvested when 80% of the leaf surface is yellow-green and 2 / 3 of the main veins turn white.

[0053] Comparative Example 1

[0054] The lower tobacco leaves were harvested at normal maturity. After harvesting, the conventional baking process (patent number: CN201110065154, announcement number: CN 102106598 B) was adopted, and the rest of the treatment was the same as in Example 1.

[0055] Comparative Example 2

[0056] The middle tobacco leaves were harvested at normal maturity. After harvesting, the conventional baking process (patent number: CN201110065154, announcement number: CN 102106598 B) was adopted, and the rest of the treatment was the same as in Example 2.

[0057] Comparative Example 3

[0058] The upper tobacco leaves were harvested at normal maturity. After harvesting, the conventional baking process (patent number: CN201110065154, announcement number: CN 102106598 B) was adopted, and the rest of the treatment was the same as in Example 3.

[0059] Result analysis:

[0060] 1. The influence of different curing processes on the grade structure of flue-cured tobacco leaves

[0061] Table 1 Effects of different curing processes on the grade structure of flue-cured tobacco leaves

[0062]

[0063] As shown in Table 1, the proportion of medium tobacco in the lower and middle parts of the tobacco leaves treated by the baking process of the present invention decreased significantly, the proportion of high-quality tobacco increased significantly, and the average price increased significantly by 1.37 yuan / kg; the proportion of high-quality tobacco in the upper part of the tobacco leaves increased by 25.2 percentage points, and the average price increased by 4.91 yuan / kg.

[0064] 2. Appearance quality of tobacco leaves after different baking processes

[0065] Table 2 Appearance identification of tobacco leaves after different baking processes at different parts

[0066]

[0067] The appearance quality of each part of the tobacco leaves treated by the baking process of the present invention is significantly improved after baking. The total weighted scores of the appearance quality of the lower leaves and the middle leaves are respectively increased by 0.325 points and 0.375 points, which are mainly manifested in brighter color, pure orange, moderate texture, and increased oil content; the total score of the upper leaves is increased by 0.3 points, which is mainly manifested in orange color, improved maturity, and full and bright chroma.

[0068] 3. Main chemical components of tobacco after different baking processes

[0069] Table 3 Main chemical components of tobacco smoke after different curing processes

[0070]

[0071] The chemical composition of the flue-cured tobacco is shown in Table 3. The flue-curing process of the present invention increases the reducing sugar and total sugar in each part, and reduces the starch, total nitrogen and protein contents, which means that the process of the present invention degrades macromolecules more fully and the chemical composition of the flue-cured tobacco leaves is more coordinated.

[0072] 4. Sensory quality of smoked tobacco from different parts after different baking processes

[0073] Table 4 Sensory quality of smoked tobacco of different parts after baking with different baking processes

[0074]

[0075] As shown in Table 4, the fresh and sweet aroma style of tobacco leaves treated by the baking process of the present invention is more prominent, and the typicality of the fresh and sweet aroma style of the lower, middle and upper tobacco leaves is increased by 0.6, 0.8 and 0.8 points respectively; the sensory evaluation quality is significantly better than that of the control, and the total weighted scores of the lower, middle and upper parts are increased by 6.05, 10.05 and 7.25 points respectively.

[0076] The test varieties used in the following Examples 4 to 6 and Comparative Examples 4 to 9 were all CB-1 (standard medium-sized tobacco) varieties grown in the same field in the tobacco area of ​​Liancheng County, Longyan City. The tobacco leaves in the tobacco fields were managed according to the standardized production management of flue-cured tobacco. The tobacco fields were uniform and the maturity levels were set to M1, M2, and M3, respectively, and baked in a test oven.

[0077] Example 4

[0078] XM1: The leaves are 50% yellow-green, and the main veins begin to turn white;

[0079] The baking process is the same as that in Example 1 except that a test oven is used.

[0080] Example 5

[0081] CM2: 70% of the leaf surface is yellow-green, and the main vein turns 1 / 2 white;

[0082] The baking process is the same as that in Example 1 except that a test oven is used.

[0083] Example 6

[0084] BM2: 80% of the leaf surface is yellow-green, and the main veins turn 2 / 3 white;

[0085] The baking process is the same as that in Example 1 except that a test oven is used.

[0086] Comparative Example 4

[0087] XM2(CK): 60% of the leaves are yellow-green, and the main veins turn 1 / 3 white;

[0088] The rest is the same as Example 4.

[0089] Comparative Example 5

[0090] XM3: 70% of the leaves are yellow-green, and the main veins turn 1 / 2 white;

[0091] The rest is the same as Example 4.

[0092] Comparative Example 6

[0093] CM1: 60% of the leaf surface is yellow-green, and the main vein turns 1 / 3 white;

[0094] The rest is the same as Example 5.

[0095] Comparative Example 7

[0096] CM3: 80% of the leaf surface is yellow-green, and the main veins turn 2 / 3 white;

[0097] The rest is the same as Example 5.

[0098] Comparative Example 8

[0099] BM1: 70% of the leaf surface is yellow-green, and the main vein turns 1 / 2 white;

[0100] The rest is the same as Example 6.

[0101] Comparative Example 9

[0102] BM3: 90% of the leaves are yellow-green, and the main veins are almost completely white;

[0103] The rest is the same as Example 6.

[0104] Result analysis:

[0105] 1. Economic characteristics of tobacco leaves of different maturity after curing

[0106] Table 5 Economic characteristics of fresh tobacco leaves after flue-curing at different maturity levels at different parts of the tobacco leaves

[0107]

[0108]

[0109] Table 5 shows that the grade structure and average price of flue-cured fresh tobacco leaves vary significantly across different parts and maturity levels. In the lower leaves, the XM1 treatment had the highest proportion of high-quality tobacco, at 57.49%, and the highest average price, at 34.28 yuan / kg. XM2 had the lowest proportion of high-quality tobacco, at 47.75%, and an average price of 30.60 yuan / kg. In the middle leaves, the CM2 treatment had the highest proportion of high-quality tobacco, at 77.99%, and the highest average price, at 37.89 yuan / kg. CM3 had the second-highest proportion and average price. In the upper leaves, BM2 had the highest proportion of high-quality tobacco and the highest average price, at 57.79% and 29.74 yuan / kg, respectively, while the lowest proportion of low-quality tobacco, at 4.92%. In terms of the grade structure of flue-cured tobacco, XM1, BM2, and CM2 were the best for the lower, middle, and upper leaves, respectively.

[0110] 2. Appearance quality of fresh tobacco leaves after flue-curing at different maturity levels

[0111] Table 6 Appearance quality of fresh tobacco leaves after flue-curing at different maturity

[0112]

[0113] Table 6 shows the appearance of tobacco leaves of varying maturity after curing at various parts. From the lower leaves, the XM3 treatment showed lower identity, oil content, and color than the other two treatments, with the lowest overall appearance quality score of 7.275. XM1 had a higher overall appearance quality score of 7.575. From the middle leaves, the overall appearance quality scores of the treatments were CM2 > CM1 > CM3, with CM1 showing poorer maturity and structure, higher oil content, and stronger color. From the upper leaves, all three treatments exhibited an orange-yellow color, with BM1 showing the lowest appearance quality indicators in all other treatments, while BM2 and BM3 had similar appearance quality. In terms of appearance quality, XM1, CM2, BM2, and BM3 were the best treatments for curing tobacco leaves from various parts.

[0114] 3. Chemical composition of fresh tobacco leaves after flue-curing at different maturity

[0115] Table 7 Chemical components of fresh tobacco leaves at different maturity levels

[0116]

[0117] As shown in Table 7, in terms of the main chemical components, the sugar content, sugar-to-sugar ratio, and sugar-alkali ratio of the XM1, CM2, and BM2 treatments were higher, and the chemical composition was the most coordinated.

[0118] 4. Sensory evaluation of smoking quality of fresh tobacco leaves at different maturity levels

[0119] Table 8 Sensory quality of flue-cured tobacco at different maturity levels

[0120]

[0121] Table 8 shows that the aroma of tobacco leaves from all treatments was light and sweet, but XM1, CM2, and BM2 had the highest style typicality for the lower, middle, and upper leaves, respectively. Among the lower leaf maturity treatments, XM1 had the highest weighted total score of 65.8, followed by XM2. This was primarily reflected in XM1's best style typicality, aroma quality, aroma volume, transparency, and aftertaste, but also its lowest concentration, slightly more off-flavors, and stronger irritation. Among the middle leaf treatments, there were no differences in concentration among the treatments. CM2 had the highest weighted total score, primarily reflected in its significantly higher style typicality, aroma quality, aroma volume, transparency, aftertaste, sweetness, burnability, and ash content than the other CM2 and CM3 treatments, but also its highest off-flavors and irritation. Ash content and concentration were consistent across all treatments for the upper leaves. The weighted total score for BM2 was higher than for BM1, and higher than for BM2. BM2 had the highest aroma quality, aroma volume, transparency, aftertaste, sweetness, and burnability of the three treatments, with a total weighted score of 72.9, but exhibited a stronger punch. BM1 ranked second in total weighted score, with scores for various indicators second only to BM2, but exhibited a higher pungency. In terms of typicality of the sweet and clear aroma style and sensory smoking quality, the best treatments for the lower, middle, and upper leaves were XM1, CM2, and BM2, respectively.

[0122] In summary, XM1, CM2, and BM2 have the best economic traits and appearance quality after flue-cured tobacco leaves, the most coordinated chemical composition, the highest sensory smoking quality scores, and especially the highest typicality of the sweet and refreshing aroma style, which greatly improves the industrial availability of tobacco leaves.

[0123] The following is a baking characteristic test during the research process of the present invention:

[0124] Test variety: CB-1 (standard medium-sized tobacco) variety planted in the tobacco field in Liancheng County, Longyan City. The tobacco fields and leaves are managed according to the standardization of flue-cured tobacco production, and the tobacco fields are uniform.

[0125] Tobacco leaf harvesting: Based on the actual harvesting of flue-cured tobacco, the maturity levels of the CB-1 varieties are set at three positions: lower (X), middle (C), and upper (B). The maturity levels are set at M1, M2, and M3.

[0126] (1) Design of lower fresh tobacco maturity treatment:

[0127] XM1: The leaves are 50% yellow-green, and the main veins begin to turn white.

[0128] XM2: 60% of the leaves are yellow-green, and the main veins turn 1 / 3 white.

[0129] XM3: 70% of the leaves are yellow-green, and the main veins turn 1 / 2 white;

[0130] (2) Design of the maturity treatment of fresh tobacco in the middle part:

[0131] CM1: 60% of the leaves are yellow-green, and the main veins turn 1 / 3 white.

[0132] CM2: 70% of the leaves are yellow-green, and the main veins turn 1 / 2 white.

[0133] CM3: 80% of the leaf surface is yellow-green, and the main veins turn 2 / 3 white;

[0134] (3) Upper fresh tobacco maturity treatment design:

[0135] BM1: 70% of the leaves are yellow-green, and the main veins turn 1 / 2 white.

[0136] BM2: 80% of the leaves are yellow-green, and the main veins turn 2 / 3 white.

[0137] BM3: 90% yellow-green leaves, main veins are almost completely white

[0138] Experimental treatment: Leaves from the lower, middle and upper parts of CB-1 with basically the same maturity were selected. 30 fresh tobacco leaves were taken from each part, of which 15 leaves (every 5 leaves were a replicate, repeated three times) were hung in a dark, closed box at room temperature. Pictures were taken every 12 hours, and the proportion of yellowing and browning areas was measured to explore the baking characteristics of the tobacco leaves.

[0139] Result analysis:

[0140] Figure 1 The baking characteristics of lower leaves at different maturity levels in a dark box. Figure 1 As can be seen, the yellowing and browning rates of the lower leaves differ significantly at different maturity levels. In terms of yellowing rate, XM3 > XM2 > XM1, and in terms of browning rate, XM3 > XM2 > XM1. After XM1 leaves yellow to 80%, the yellowing rate slows down sharply, and further yellowing becomes difficult. This is primarily manifested in the main veins and four pairs of lateral veins at the leaf base. XM1 shows the latest browning, reaching 20% ​​after 72 hours. Overall, XM1 has the best baking resistance, but its yellowing rate is relatively slow. Temperatures should be raised appropriately during this period to accelerate yellowing.

[0141] Figure 2 The baking characteristics of middle leaves of different maturity in a dark box. Figure 2 It can be seen that the yellowing and browning patterns of the middle leaves at different maturity levels are consistent with those of the lower leaves. The yellowing and browning speeds are all in the order of CM3>CM2>CM1. The leaves of CM1 and CM2 are completely yellow when they are 30% brown, and the leaves of CM3 are 30% brown when they are 80% yellow. Comprehensive analysis shows that CM1 and CM2 are better at baking and baking resistance than CM3.

[0142] Figure 3 The baking characteristics of upper leaves of different maturity in a dark box. Figure 3 As can be seen, browning of the upper leaves at all maturity levels occurs early, indicating poor baking resistance. BM3 reaches 30% browning by the time it reaches 60% yellowing, while BM2 reaches 30% browning by the time it reaches 80% yellowing. BM1 exhibits both yellowing and browning more slowly. By the time it reaches 30% browning, although it has already reached 80% yellowing, it undergoes a rapid browning phenomenon. Overall, BM2 has the best baking characteristics.

[0143] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for harvesting and roasting the Cui Bi No. 1 tobacco leaves to highlight their sweet and fragrant style, characterized in that: include: S1, Harvesting: Tobacco leaves are harvested at a maturity lower than 10% of the normal maturity. Tobacco leaves of different parts are harvested according to the following standards: 50% of the lower leaves are yellow-green, and the main veins turn from green to white; 70% of the middle leaves are yellow-green, and 1 / 2 of the main veins turn white; 80% of the upper leaves are yellow-green, and 2 / 3 of the main veins turn white and shiny; S2, Installing the kang: After the tobacco leaves are braided into poles, they are placed in the dense curing room in the conventional way, and the fan is turned on and runs for 2-3 hours; S3, Bake: Bake as follows: S31, ignite, raise the temperature to 40±0.5℃ dry bulb at 0.8-1.0℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer turn 50%-60% yellow. The fan is mainly operated at low speed. Every 4 hours, the fan is operated at high speed for 30-60 minutes; S32, raise the temperature to 41±0.5℃ dry bulb at 0.25-0.3℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the high temperature layer turn 70% to 80% yellow and become soft and collapse on the rack. The fan should mainly run at medium speed. Every 6 hours, the fan should run at high speed for 30-60 minutes; S33: Raise the temperature at 0.2-0.25°C / h to a dry-bulb temperature of 42±0.5°C, maintain a wet-bulb temperature of 39±0.5°C, and stabilize the temperature until the tobacco leaves in the high-temperature layer turn 80% to 90% yellow. Then adjust the wet-bulb temperature to 38±0.5°C and stabilize the temperature until the tobacco leaves in the high-temperature layer turn 90% to 10% yellow, i.e., yellow leaves with blue veins, completely yellow leaves with only the main vein and 2-3 pairs of lateral veins at the base green, and the tobacco leaves lose water to the point of curling. The fan is running at high speed. S34, raise the temperature to 44±0.5℃ dry bulb at 0.2-0.25℃ / h, maintain wet bulb at 37±0.5℃, and stabilize the temperature until the tobacco leaves in the low temperature layer turn 90% to 10% yellow, i.e. yellow leaves with blue veins, completely yellow leaves with only the main vein and 2-3 pairs of side veins at the base green, and the tobacco leaves lose water to the point of curling, and the fan runs at high speed; S35, raise the temperature at 0.25-0.3℃ / h to 46±0.5℃ dry bulb, maintain 38±0.5℃ wet bulb, and stabilize the temperature until the tobacco leaves in the high temperature layer are completely yellow, that is, yellow leaves and white veins, the leaves are completely yellow, all leaf veins are completely white, the tobacco leaves are 2 / 3 dry, and the appearance is small rolls. The fan speed is running at medium speed; S36, raise the temperature to 48±0.5℃ dry bulb at 0.25-0.3℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the tobacco leaves in the low temperature layer are completely yellow, that is, yellow leaves and white veins, the leaves are completely yellow, all the veins are completely white, the tobacco leaves are 2 / 3 dry, and the appearance is small rolls. The fan speed is operated at medium speed; S37, raise the temperature to 50±0.5℃ dry bulb at 0.3-0.5℃ / h, maintain the wet bulb at 38±0.5℃, and stabilize the temperature until the high temperature layer and the middle layer of tobacco leaves are 4 / 5 dry and the appearance is large rolls. The fan speed is operated at medium speed; S38, raise the temperature to 54±0.5℃ dry bulb at 0.3-0.5℃ / h, maintain the wet bulb at 39±0.5℃, and stabilize the temperature until the tobacco leaves in the flue-curing room are completely dry except for the main veins, and the main veins are more than 1 / 3 dry, that is, the whole flue-cured tobacco leaves have the appearance of large rolls, and the fan speed is operated at medium speed; S39, increase the temperature at 0.5-1°C / h to 60±0.5°C dry bulb, maintain 40±0.5°C wet bulb, run for 8-10 hours, and run the fan at medium speed; S40: Raise the temperature to 65±0.5℃ dry bulb at 0.5-1℃ / h, maintain the wet bulb at 41±0.5℃, and operate until the main vein of the whole flue-cured tobacco leaves are completely dry. The fan speed is operated at a low speed. The high speed range of the fan is 1300-1500 rpm, the medium speed range is 940-980 rpm, and the low speed range is 700-750 rpm.

2. The roasting method according to claim 1, characterized in that: The high speed of the fan is 1440 rpm, the medium speed is 960 rpm, and the low speed is 720 rpm.

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