A method of curing air-cured tobacco and a non-combustible cigarette

Abstract

This application provides a method for preparing sun-cured tobacco. By baking the sun-cured tobacco, extending the baking time in the later stages of yellowing, and immediately switching to a color-fixing period when brown spots appear on the leaves, the dehumidification process is intensified. Ultimately, this ensures that the tobacco leaves are fully brown while minimizing the percentage of green veins on the main veins. Experimental results show that the method provided in this application retains the high aroma and strength of sun-cured tobacco, improves its irritation, taste, and aroma penetration, making it suitable for use with flue-cured tobacco as a raw material for non-combustible cigarettes. This effectively compensates for the poor aroma and strength of flue-cured tobacco under non-combustible heating methods, making it closer to the smoking experience of traditional cigarettes.

Description

Technical Field

[0001] This invention relates to the field of tobacco technology, and more particularly to a method for preparing sun-cured tobacco and a non-combustible cigarette. Background Technology

[0002] Non-combustible cigarettes deliver nicotine to the user by heating the tobacco raw materials instead of burning them. This significantly reduces the amount of harmful substances in the smoke, making them more beneficial to the user's health compared to traditional cigarettes. However, the low-temperature heating method makes it difficult for the tobacco and other raw materials to fully release their inherent strength and aroma. Flavoring is then added to enhance the flavor and strength of the smoke, but this can result in an unnatural aroma and a less satisfying experience. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing sun-cured tobacco and a non-combustible cigarette. The method provided by this application can increase the content of aroma substances and the concentration of smoke in sun-cured tobacco, thereby improving the inhalability of the non-combustible cigarette.

[0004] In my country, tobacco processing methods include flue-cured tobacco and sun-cured tobacco. Flue-cured tobacco uses a three-stage curing process—yellowing, color fixing, and drying—to alter the internal chemical composition and appearance of the tobacco leaves. Sun-cured tobacco, on the other hand, utilizes natural light and airflow. These two methods have different requirements for the variety of tobacco leaves, and the resulting leaves differ significantly in aroma, nicotine, and tar content. Sun-cured tobacco varieties are characterized by their inherently high aroma, but they also suffer from high irritation and poor taste. While sun-curing can further enhance the unique aroma of sun-cured tobacco, the changes in its internal chemical composition amplify these drawbacks.

[0005] Therefore, the applicant considered retaining the high aroma and strength of sun-cured tobacco while improving its irritation, taste, and aroma penetration, so that it could be used in combination with flue-cured tobacco as a raw material for non-combustible cigarettes. This would effectively compensate for the shortcomings of flue-cured tobacco in terms of aroma and strength when heated without combustion, making it closer to the smoke of traditional cigarettes.

[0006] In view of this, the present invention provides a method for preparing sun-dried tobacco, comprising the following steps:

[0007] The sun-dried tobacco harvested in the field is first-stage cured at a dry-bulb temperature of 23-30℃ and a wet-bulb temperature of 23-30℃.

[0008] After adjusting the dry bulb temperature to 32-34℃, proceed with the second stage of baking until the leaves are completely yellow.

[0009] The third stage of baking was carried out by adjusting the dry bulb temperature to 38-40℃ and the wet bulb temperature to 36-38℃ until brown spots appeared on the leaves.

[0010] The wet-bulb temperature was adjusted to 34–36℃ for the fourth stage of baking until the browning area of ​​the leaves reached 30%–70%.

[0011] The fifth stage of baking was carried out by adjusting the dry bulb temperature to 45-47℃ and the wet bulb temperature to 31-33℃ until the leaves were dry.

[0012] The dry bulb temperature is controlled at 60-68℃ and the wet bulb temperature at 29-35℃ for the sixth stage of baking until the leaf veins are completely dry, thus obtaining the prepared sun-dried tobacco.

[0013] This application employs a high-temperature baking method to improve upon the shortcomings of sun-cured tobacco. However, the color of the tobacco leaves after baking directly affects their quality. This is because the color changes before and after baking are based on the Maillard reaction occurring within the tobacco leaves during the baking process, and directly relate to the degree of aroma conversion. Sun-cured tobacco undergoes a browning (reddening) process, and brown is considered the best grade for sun-cured tobacco, while orange and lemon colors are preferred for flue-cured tobacco. If flue-cured tobacco turns brown, it will generally be classified as a low-grade mixed-color tobacco. Therefore, the parameters during high-temperature baking are crucial to the baking effect of sun-cured tobacco. This application bakes sun-cured tobacco, extending the baking time in the later stages of yellowing. When brown spots appear on the leaves, the baking is immediately switched to the color-fixing stage, and the dehumidification is increased. Ultimately, this ensures that the tobacco leaves are fully brown while minimizing the pre-vein blue vein ratio.

[0014] Meanwhile, the maturity of the tobacco leaves is limited in the traditional field planting process of sun-cured tobacco. This allows for a general limitation on the internal chemical composition of the tobacco leaves before curing, thereby controlling the quantity and properties of precursors in the chemical reactions during curing. Ultimately, this is reflected in the coordination of the internal chemical composition of the cured tobacco leaves. Furthermore, the cured sun-cured tobacco can release sufficient strength and aroma when heated at low temperatures. Therefore, when used as a raw material for non-combustible cigarettes and smoked, it can provide a more natural smoke with higher aroma and strength, thereby increasing the market acceptance and market share of non-combustible cigarettes.

[0015] Here is an explanation of some of the terms:

[0016] 1) Dryness degree, which is the dryness state reflected in the appearance of the tobacco leaves due to the reduction of moisture content. The dryness degree is roughly divided into the following from low to high: wilted and collapsed leaves (softened), hooked tips and curled edges (dry tips), near small roll, small roll, near large roll, large roll, and dry veins.

[0017] 2) Degree of yellowing, that is, the degree to which the leaves turn yellow as a whole. It is usually expressed as a percentage of the leaf area that has turned yellow, such as 10% of the leaf area turning yellow. When the leaves and veins turn completely yellow, it is called "complete yellow", also known as "yellow leaves and yellow veins".

[0018] 3) Maturity: Current technology classifies the field harvest maturity of sun-cured tobacco into four levels:

[0019] Unripe: The main vein of the tobacco leaf is green, the secondary veins are shiny, the leaf tip, leaf margin and leaf surface are all green, the hairs have not fallen off, and there are no ripe spots;

[0020] Early maturity: About 1 / 3 of the main vein of the tobacco leaf turns white, the secondary veins become shiny, the leaf tips and edges turn yellow, the leaf surface is 30-40% yellow, less downy hairs fall off, and there are no mature spots.

[0021] When the tobacco leaves are at the right maturity stage: about 2 / 3 of the main veins turn white, about 1 / 3 of the lateral veins turn white, the tips and edges of the leaves turn yellow, the leaf surface is 50-60% yellow, the pubescent parts fall off, and about 30% of the leaves have mature spots.

[0022] Overripe: About 2 / 3 of the main veins of the tobacco leaves turn white, about 1 / 2 of the lateral veins turn white, the leaf tips and edges turn yellow, the leaf surface is 70-80% yellow, most of the pubescence falls off, and about 50% of the leaves have mature spots.

[0023] In some specific implementations, the modulation method provided by the present invention has the following steps: the first stage baking time is 13-15 hours; the second stage baking time is 70-71 hours; the third stage baking time is 11-13 hours; the fourth stage baking time is 18-26 hours; the fifth stage baking time is 20-60 hours; and the sixth stage baking time is 47-60 hours.

[0024] In some specific implementations, the dry bulb temperature in the first stage of baking is 23.7℃ and the wet bulb temperature is 23.3℃; the dry bulb temperature in the second stage of baking is 33℃; the dry bulb temperature in the third stage of baking is 39℃ and the wet bulb temperature is 37℃; the wet bulb temperature in the fourth stage of baking is 35℃; the dry bulb temperature in the fifth stage of baking is 46℃ and the wet bulb temperature is 32℃; and the dry bulb temperature in the sixth stage of baking is 60-68℃ and the wet bulb temperature is 34℃.

[0025] In some specific implementations, this application applies different treatments to the middle and upper leaves of sun-dried tobacco, specifically including:

[0026] The middle leaves of sun-dried tobacco harvested in the field were subjected to the first stage of baking at a dry bulb temperature of 23-24℃ and a wet bulb temperature of 23-24℃ for 13 hours.

[0027] After adjusting the dry bulb temperature to 32-34℃, the second stage of baking is carried out, baking for 70 hours until the leaves are completely yellow.

[0028] The third stage of baking was carried out by adjusting the dry bulb temperature to 38-40℃ and the wet bulb temperature to 36-38℃, and baking for 11 hours until brown spots appeared on the leaves.

[0029] The wet-bulb temperature was adjusted to 34-36℃ for the fourth stage of baking, which lasted for 26 hours until the browning area of ​​the leaves reached 30%-70%.

[0030] The fifth stage of baking was carried out by adjusting the dry bulb temperature to 45-47℃ and the wet bulb temperature to 31-33℃, and baking for 59 hours until the leaves were dry.

[0031] The sixth stage of baking was carried out by adjusting the dry bulb temperature to 60-68℃ and the wet bulb temperature to 33-35℃. After baking for 60 hours and the leaf veins were completely dry, the prepared sun-dried tobacco was obtained.

[0032] For the upper leaves, the treatment method is as follows:

[0033] The upper leaves of sun-dried tobacco harvested in the field are subjected to the first stage of baking at a dry bulb temperature of 23-24℃ and a wet bulb temperature of 23-24℃ for 15 hours.

[0034] After adjusting the dry bulb temperature to 32-34℃, the second stage of baking is carried out, and baking is carried out for 71 hours until the leaves are completely yellow.

[0035] The third stage of baking was carried out by adjusting the dry bulb temperature to 38-40℃ and the wet bulb temperature to 36-38℃, and baking for 13 hours until brown spots appeared on the leaves.

[0036] The fourth stage of baking was carried out by adjusting the wet bulb temperature to 34-36℃ and baking for 18 hours until the brown area of ​​the leaf surface reached 30%-70%.

[0037] The fifth stage of baking was carried out by adjusting the dry bulb temperature to 45-47℃ and the wet bulb temperature to 31-33℃, and baking for 20 hours until the leaves were dry.

[0038] The sixth stage of baking was carried out by adjusting the dry bulb temperature to 60-68℃ and the wet bulb temperature to 33-35℃, and baking for 47 hours until the leaf veins were completely dry to obtain the prepared sun-dried tobacco.

[0039] In some specific implementations, the fourth stage of baking until the brown area of ​​the leaf surface reaches 1 / 3 to 2 / 3 can ensure that the main vein of the tobacco leaf is minimized while the tobacco leaf is fully brown.

[0040] In some specific implementations, the field harvest maturity of the sun-dried tobacco is as follows: the main vein of the tobacco leaf turns white in 1 / 3 to 2 / 3 of its length, the secondary veins turn white in 1 / 3 of their length, the leaf tips and edges turn yellow, and the leaf surface is 50% to 60% yellow.

[0041] In some specific implementations, the field harvest maturity of the sun-dried tobacco also includes the appearance of mature spots on 20% to 40% of the leaf area.

[0042] In some specific implementations, the field harvest maturity of the sun-dried tobacco exhibits the following agronomic performance parameters: 2 / 3 of the main veins of the tobacco leaves turn white, 1 / 3 of the lateral veins turn white, the leaf tips and edges turn yellow and 5-6% of the leaf surface turns yellow, and 30% of the leaf area shows mature spots.

[0043] This invention also provides a type of sun-cured tobacco prepared by the modulation method described above. This sun-cured tobacco, through a heating and baking process, retains the high aroma and strength characteristics of sun-cured tobacco while improving its irritation, taste, and aroma profile. Experimental results show that the total amount of neutral aroma compounds in the heat-modified sun-cured tobacco increases by 33% to 102% compared to flue-cured tobacco. The significant increase in aroma compound content is the main reason for the improved aroma, and the nicotine content is more than twice that of flue-cured tobacco. Compared to sun-cured tobacco, the sugar-to-nicotine ratio of the heat-modified sun-cured tobacco is significantly higher, thus reducing irritation and improving taste.

[0044] This invention also provides a non-combustible cigarette, comprising sun-cured tobacco prepared by the modulation method described above. The modulation method provided in this application retains the high aroma and strength of sun-cured tobacco, improving its irritation, taste, and aroma penetration. This allows it to be used in conjunction with flue-cured tobacco as a raw material for non-combustible cigarettes, effectively compensating for the shortcomings of flue-cured tobacco in terms of aroma and strength when heated without combustion, making it closer to the smoking experience of traditional cigarettes.

[0045] This application involves curing sun-cured tobacco, extending the curing time in the later stages of yellowing, and immediately switching to a color-fixing period when brown spots appear on the leaves, while increasing dehumidification. Ultimately, this ensures that the leaves are fully brown while minimizing the percentage of green veins on the main veins. Experimental results show that the method provided in this application retains the high aroma and strength of sun-cured tobacco, improves its irritation, taste, and aroma penetration, making it suitable for use with flue-cured tobacco as a raw material for non-combustible cigarettes. This effectively compensates for the poor aroma and strength of flue-cured tobacco under non-combustible heating methods, making it closer to the smoking experience of traditional cigarettes. Attached Figure Description

[0046] Figure 1 Comparison of the appearance of middle leaves harvested in the field at different stages of maturity;

[0047] Figure 2 Comparison of appearance changes of the middle leaves harvested in the field under dark box test;

[0048] Figure 3 A graph showing the trend of appearance changes of the middle leaves harvested in the field under a dark box experiment;

[0049] Figure 4 A graph showing the trend of water loss rate of the middle leaves harvested in the field under a dark box test;

[0050] Figure 5 Images showing the leaf changes and grading of the middle leaves after baking using a baking process;

[0051] Figure 6 Images showing the leaf changes and grading of the middle leaves after a second baking process;

[0052] Figure 7 Images showing the leaf changes and grading of the middle leaves after three baking processes. Detailed Implementation

[0053] The following embodiments further illustrate the method for preparing sun-dried tobacco and the non-combustible cigarettes provided by the present invention.

[0054] The following examples all use Piaohe No. 2 sun-dried tobacco, and the test site is Hongxing Village, Sanyuanpu Town, Liuhe County, Tonghua City, Jilin Province, China.

[0055] (I) Field Trial Conditions

[0056] The tobacco fields were planted using a randomized block design, with a row spacing of 1.2m and a plant spacing of 0.5m. The fertilizers used were tobacco-specific compound fertilizer, ammonium sulfate, and potassium sulfate. The total nitrogen application rate was 4.5 kg / mu, with a nitrogen-phosphorus-potassium ratio of 1:1.2:3. Compound fertilizer was applied at transplanting, while ammonium sulfate and potassium sulfate were applied 35 days after transplanting. Other cultivation and management practices followed local best practices.

[0057] (II) Selection of field harvest maturity

[0058] Four maturity levels are set, with the following criteria:

[0059] M0 maturity (unripe): The main vein of the tobacco leaf is green, the secondary veins are shiny, the leaf tip, leaf margin and leaf surface are all green, the hairs have not fallen off, and there are no ripe spots;

[0060] M1 maturity (early maturity): About 1 / 3 of the main vein of the tobacco leaf turns white, the secondary veins are shiny, the leaf tip and edge turn yellow, the leaf surface is 30-40% yellow, the downy hairs fall off less, and there are no mature spots.

[0061] M2 maturity (suitable maturity): About 2 / 3 of the main veins of the tobacco leaves turn white, about 1 / 3 of the lateral veins turn white, the tips and edges of the leaves turn yellow significantly, the leaf surface is 50-60% yellow, the pubescence is lost, and about 30% of the leaves have mature spots.

[0062] M3 maturity (overripe): About 2 / 3 of the main vein of the tobacco leaf turns white, and about 1 / 2 of the lateral veins turn white.

[0063] The middle leaves of the above four maturity levels, such as Figure 1 As shown, Figure 1 Comparison of the appearance of middle leaves harvested in the field at different stages of maturity.

[0064] A dark-box experiment was conducted, in which three tobacco leaves of each of four maturity levels were picked and placed in a dark, well-ventilated area. Photos were taken from both sides every 12 hours. The changes in the middle leaves of the four maturity levels were observed as follows: Figure 2 As shown, record the yellowing and browning percentages, and simultaneously measure the weight of each tobacco leaf to obtain the water loss rate. Figure 3 and Figure 4 As shown, Figure 2 Comparison of appearance changes of the middle leaves harvested in the field under dark box experiments. Figure 3 This is a graph showing the trend of appearance changes of the middle leaves harvested in the field under a dark box experiment. Figure 4 This is a graph showing the trend of water loss rate of the middle leaves harvested in the field under a dark chamber test.

[0065] Depend on Figure 2 and Figure 3 It can be seen that the time points for the yellowing and browning of tobacco leaves at different maturity levels are different. Overall, M3 tobacco leaves start yellowing the fastest and take the shortest time to reach full yellow color, followed by M2 and M1. M0 tobacco leaves start yellowing the slowest and take the longest time to reach full yellow color. Under the same dark chamber conditions, M3 tobacco leaves yellow relatively quickly, requiring 48 hours to reach full yellow color. M2 and M1 tobacco leaves are next, requiring 60 hours and 72 hours respectively to reach full yellow color. M0 tobacco leaves have the slowest yellowing rate and take the longest time, requiring 108 hours to reach full yellow color.

[0066] The browning start time for M3 is earlier than that for M2, M2 is earlier than that for M1, and M1 is earlier than that for M0. The time for M3 tobacco leaves to reach full brownness is similar to that for M2, both around 32 hours. The browning rate of M3 and M2 is faster than that of M0 and M1. M1 takes 144 hours to fully brown, while M0 takes 156 hours to fully brown.

[0067] Depend on Figure 4 It can be seen that under dark chamber conditions, the water loss rate of tobacco leaves at different maturity levels gradually increased with the increase of drying time, generally showing a trend of rapid initial loss followed by slower loss. Among different treatments, the order of water loss at each time point was M3 > M1 > M2 > M0, with M3 tobacco leaves showing the fastest water loss rate. There was no significant difference between M0 and M2 within 96 hours after harvest, but after 96 hours, the water loss rate of M2 was greater than that of M0. The water loss rates of the four treatments M0, M1, M2, and M3 reached 41.84%, 43.14%, 42.31%, and 45.50% at 156 hours, respectively. This indicates that under the same dark chamber conditions, tobacco leaves treated with M3 were more prone to water loss.

[0068] Based on the requirements that tobacco leaves with good yellowing characteristics are easy to cure and that do not turn brown over a long period of time have good curing resistance, it can be seen that the ease of curing of tobacco leaves in each treatment is M3>M2>M1>M0, and the curing resistance is M0>M1>M2>M3. In addition, the internal components of leaves of M2 are more coordinated. Therefore, the maturity of M2, i.e., the appropriate maturity, is selected as the standard for field harvesting maturity.

[0069] (III) Baking Test

[0070] Small-batch drying was conducted using an intelligent drying oven, employing three different drying processes to dry tobacco leaves at maturity level M2. During the drying process, photos were taken every 12 hours to record the drying process. Details for the middle leaves can be found [link to details]. Figure 5 , Figure 6 and Figure 7 , Figure 5 Images showing the leaf changes and grading of the middle leaves after baking using a baking process; Figure 6 Images showing the leaf changes and grading of the middle leaves after a second baking process; Figure 7 Images showing the leaf changes and grading of the middle leaves after three baking processes.

[0071] In addition, three different curing processes were used for curing in large curing barns, and the tobacco leaves after curing in large curing barns were classified by color into brown tobacco, yellow tobacco, and mixed red and yellow tobacco leaves, with Liuhe flue-cured tobacco and Jiaohe sun-cured red tobacco as comparisons.

[0072] The three different baking processes mentioned above are as follows:

[0073] (1) Baking Process 1 (Baking without retaining the browning stage):

[0074] A: After the tobacco leaves are loaded, the baking process begins. The dry bulb temperature is 30℃ and the wet bulb temperature is 30℃. This stage takes 15 hours.

[0075] B: Continue baking at a dry bulb temperature of 34°C and a wet bulb temperature of 33°C for 83 hours.

[0076] C: When the leaves are almost completely yellow, turn the heat to a dry bulb temperature of 37°C and a wet bulb temperature of 34°C and continue baking. This stage takes 8 hours.

[0077] D: When the leaves turn completely yellow, continue baking until the dry bulb temperature reaches 41℃ and the wet bulb temperature reaches 29℃. This stage takes 19 hours.

[0078] E: When the leaves are 1 / 3 dry, turn the heat to 47°C for dry bulb and 29°C for wet bulb, and continue baking. This stage takes 45 hours.

[0079] F: Once the leaves are completely dry, turn the heat to 60℃ and continue baking until the veins are completely dry. This stage takes 35 hours.

[0080] After curing, the tobacco leaves consisted of 20.5% roasted palm tobacco, 30.8% roasted yellow tobacco, 35.9% mixed colors, and 12.8% green veins.

[0081] ② Baking Process Two (Baking that retains the browning stage)

[0082] A: After the tobacco leaves are loaded, the baking process begins. The dry bulb temperature is 30℃ and the wet bulb temperature is 30℃. This stage takes 15 hours.

[0083] B: Continue baking at a dry bulb temperature of 34°C and a wet bulb temperature of 33°C for 83 hours.

[0084] C: When the leaves are almost completely yellow, turn the heat to a dry bulb temperature of 39°C and a wet bulb temperature of 37°C and continue baking. This stage takes 10 hours.

[0085] D: Brown spots appear on the leaves. The wet bulb temperature drops to 35°C, while the dry bulb temperature remains unchanged and baking continues. This stage takes 74 hours.

[0086] E: When the leaves turn brown by 1 / 3, turn the heat to a dry bulb temperature of 45-46℃ and a wet bulb temperature of 29℃ and continue baking. This stage takes 22 hours.

[0087] F: After the leaves are dried, turn the heat to a dry bulb temperature of 60°C and a wet bulb temperature of 29°C and continue baking until the veins are completely dry. This stage takes 24 hours.

[0088] After curing, the tobacco leaves consist of 53% roasted palm tobacco, 28% roasted yellow tobacco, and 19% mixed-color tobacco.

[0089] ③ Baking process three (i.e., the baking process using the technical solution of this application)

[0090] Middle leaf:

[0091] A) After preheating the drying oven to a dry bulb temperature of 23.7℃ and a wet bulb temperature of 23.3℃, ​​load the smoke and bake for 13 hours;

[0092] B) Adjust the dry bulb temperature to 33℃ and bake for 70 hours until the leaves are completely yellow;

[0093] C) Adjust the dry bulb temperature to 39℃ and the wet bulb temperature to 37℃ and bake for 11 hours, until brown spots appear on the leaves;

[0094] D) Adjust the wet-bulb temperature to 35℃ and bake for 26 hours, until 2 / 3 of the leaf surface turns brown;

[0095] E) Adjust the temperature to dry bulb 46℃ and wet bulb 32℃ and bake for 59 hours until the leaves are dry;

[0096] F) Adjust the dry bulb temperature to 60℃ and the wet bulb temperature to 34℃, and bake for 60 hours until the leaf veins are completely dry.

[0097] After curing, the tobacco leaves consist of 66% roasted palm tobacco, 24% roasted yellow tobacco, and 10% mixed-color tobacco.

[0098] Upper leaves:

[0099] A) After preheating the drying oven to a dry bulb temperature of 23.7℃ and a wet bulb temperature of 23.3℃, ​​load the tobacco and bake for 15 hours;

[0100] B) Adjust the dry bulb temperature to 33℃ and bake for 71 hours until the leaves are completely yellow;

[0101] C) Adjust the dry bulb temperature to 39℃ and the wet bulb temperature to 37℃, and bake for 13 hours until brown spots appear on the leaves;

[0102] D) Adjust the wet-bulb temperature to 35℃ and bake for 18 hours until 2 / 3 of the leaf surface turns brown.

[0103] E) Adjust the dry bulb temperature to 46℃ and the wet bulb temperature to 32℃, and bake for 20 hours until the leaves are dry;

[0104] F) Adjust the temperature to 60℃ for dry bulb and 34℃ for wet bulb, and bake for 47 hours until the leaf veins are completely dry.

[0105] After curing, the tobacco leaves consist of 69% roasted palm tobacco, 19% roasted yellow tobacco, and 13% mixed-color tobacco.

[0106] Because of the differences in the curing environment between curing barns and intelligent curing cabinets, curing in a curing barn will result in a relatively higher yield of low-value tobacco leaves such as those with discoloration and green veins compared to curing in an intelligent curing cabinet.

[0107] Furthermore, regarding the quality grading of tobacco leaves, the color of the cured tobacco leaves is positively correlated with their internal quality. Therefore, in the grading of cured tobacco leaves using processes one, two, and three, the tobacco leaves from process three have the lowest proportion of mixed-color tobacco and the highest proportion of brown and yellow tobacco, indicating that process three is significantly superior to processes one and two.

[0108] (IV) Results Analysis

[0109] (1) The samples obtained from baking process three were subjected to routine chemical tests. The results are shown in Tables 1 and 2.

[0110] Table 1. Routine chemical composition of the middle leaves after roasting

[0111]

[0112] Table 2. Routine chemical composition of upper leaves after roasting

[0113]

[0114] As shown in Tables 1 and 2, in terms of the coordination of conventional chemical components, roasted palm tobacco is superior to roasted yellow tobacco, and roasted yellow tobacco is superior to mixed-color tobacco.

[0115] (2) The samples obtained from the third baking process and the control samples were made into single-material tobacco and the sensory quality was evaluated. The aroma quality, aroma quantity, off-flavors, irritation, concentration, strength and aftertaste were scored using a nine-point scale and the average value of the sensory scores of multiple people was calculated. The results are shown in Table 3. Table 3 shows the sensory quality evaluation results of the samples prepared in the examples and comparative examples of this application.

[0116] The control samples were selected from the flue-cured tobacco variety Jiyan No. 9 and the sun-dried and blended Piaohe No. 2. Jiyan No. 9 is a conventional flue-cured tobacco product from the field test site.

[0117] Among them, Jiyan No. 9 uses the upper leaves of orange-yellow grade 2 (B2F) which have the highest industrial application value; Piaohe No. 2, which is dried and processed, uses the upper leaves of reddened leaves which have the highest industrial application value.

[0118] Table 3. Sensory quality evaluation results of samples prepared in the embodiments and comparative examples of this application.

[0119] sample Fragrance Aroma Mixed gases Irritating concentration energy Aftertaste Upper leaves of flue-cured yellow tobacco 5.4 5.8 5.3 5.4 6.0 5.9 5.4 Upper leaf roasted palm tobacco 5.6 5.6 5.3 5.4 5.8 5.5 5.4 Upper leaf variegated tobacco 5.3 5.4 5.4 5.5 5.6 5.5 5.3 Central leaf flue-cured yellow tobacco 5.5 5.5 5.2 5.2 5.8 5.9 5.3 Central leaf roasted palm tobacco 5.5 5.4 5.2 5.3 5.7 5.8 5.3 Middle Leaf Variegated Tobacco 5.2 5.1 5.3 5.4 5.5 5.6 5.1 The upper part of the drifting river No. 2 was sunburned. 5.8 6.0 5.6 6.0 6.0 7.0 5.8 Jiyan No. 9 B2F 4.0 4.0 5.9 4.5 4.0 3.5 5.0

[0120] As can be seen from the analysis in Table 3:

[0121] A) The aroma quality, aroma quantity, concentration, strength and aftertaste of the smoke produced by the three-stage roasting process are comparable to the sun-dried tobacco from the upper part of Piaohe No. 2, and far superior to Jiyan No. 9 B2F.

[0122] B) Impurities: The smoke produced after three baking processes and sun-dried tobacco was lower than that of the upper part of Piaohe No. 2 sun-dried tobacco and Jiyan No. 9 B2F.

[0123] C) Irritating, after the baking process, the smoke from the sun-drying process is lower than that of the upper part of Piaohe No. 2.

[0124] Therefore, the middle leaf flue-cured yellow tobacco and the upper leaf flue-cured brown tobacco obtained by the three-stage curing process have good indicators and meet the requirements of high aroma, low impurities and low irritation. They are high-quality flue-cured tobacco leaves that can be developed and utilized.

[0125] (3) The neutral aroma components of the samples obtained by baking process 3 and the control samples were detected. The analysis results are shown in Table 4. Table 4 shows the total neutral aroma components of the samples prepared by the examples and comparative examples of this application.

[0126] The control samples were selected from the flue-cured tobacco variety Jiyan No. 9 and the sun-dried and blended Piaohe No. 2. Jiyan No. 9 is a conventional flue-cured tobacco product from the field test site.

[0127] Among them, Jiyan No. 9 uses the upper leaves of orange-yellow grade 2 (B2F) which have the highest industrial application value; Piaohe No. 2, which is dried and processed, uses the upper leaves of reddened leaves which have the highest industrial application value.

[0128] Table 4. Detection results of total neutral fragrance components in samples prepared according to the embodiments and comparative examples of this application.

[0129]

[0130] As shown in Table 4, the total amount of neutral aroma components in the samples obtained by the method provided in this application is significantly higher than that of the flue-cured tobacco variety Jiyan 9 and the sun-cured Piaohe 2.

[0131] Based on the above analysis, the sun-curing process provided by this application achieves the goals of reducing the irritation of sun-cured tobacco, improving its taste, and preserving its high aroma. When applied to the raw materials of non-combustible cigarettes, it can compensate for the shortcomings of non-combustible cigarettes, such as poor aroma, weak flavor, and unnatural taste.

[0132] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing sun-cured tobacco, comprising the following steps: The middle leaves of sun-dried tobacco harvested in the field were subjected to the first stage of baking at a dry bulb temperature of 23-24℃ and a wet bulb temperature of 23-24℃ for 13 hours. After adjusting the dry bulb temperature to 32~34℃, the second stage of baking is carried out, baking for 70 hours until the leaves are completely yellow. The third stage of baking was carried out by adjusting the dry bulb temperature to 38~40℃ and the wet bulb temperature to 36~38℃, and baking for 11 hours until brown spots appeared on the leaves. The fourth stage of baking was carried out by adjusting the wet-bulb temperature to 34~36℃ and baking for 26 hours until the browning area of ​​the leaf surface reached 30%~70%. The fifth stage of baking was carried out by adjusting the dry bulb temperature to 45~47℃ and the wet bulb temperature to 31~33℃, and baking for 59 hours until the leaves were dry. The sixth stage of baking is carried out by adjusting the dry bulb temperature to 60~68℃ and the wet bulb temperature to 33~35℃. After baking for 60 hours until the leaf veins are completely dry, the prepared sun-dried tobacco is obtained. The upper leaves of sun-dried tobacco harvested in the field are subjected to the first stage of baking at a dry bulb temperature of 23-24℃ and a wet bulb temperature of 23-24℃ for 15 hours. After adjusting the dry bulb temperature to 32~34℃, the second stage of baking is carried out, baking for 71 hours until the leaves are completely yellow. The third stage of baking was carried out by adjusting the dry bulb temperature to 38~40℃ and the wet bulb temperature to 36~38℃, and baking for 13 hours until brown spots appeared on the leaves. The fourth stage of baking was carried out by adjusting the wet-bulb temperature to 34~36℃ and baking for 18 hours until the browning area of ​​the leaf surface reached 30%~70%. The fifth stage of baking was carried out by adjusting the dry bulb temperature to 45~47℃ and the wet bulb temperature to 31~33℃, and baking for 20 hours until the leaves were dry. The sixth stage of baking is carried out by adjusting the dry bulb temperature to 60~68℃ and the wet bulb temperature to 33~35℃, and baking for 47 hours until the leaf veins are completely dry to obtain the prepared sun-dried tobacco.

2. The modulation method according to claim 1, characterized in that, The fourth stage of baking is carried out until the browning area of ​​the leaf surface reaches 1 / 3 to 2 / 3.

3. The modulation method according to claim 1, characterized in that, The field harvest maturity of the sun-dried tobacco is as follows: the main vein of the tobacco leaf turns white in 1 / 3 to 2 / 3, the lateral veins turn white in 1 / 3, the leaf tip and leaf edge turn yellow, and the leaf surface is 50% to 60% yellow.

4. The modulation method according to claim 3, characterized in that, The field harvest maturity of sun-dried tobacco also includes the appearance of mature spots on 20% to 40% of the leaf area.

5. Sun-cured tobacco prepared by the modulation method according to any one of claims 1 to 4.

6. A non-combustible cigarette, comprising sun-cured tobacco prepared by the modulation method according to any one of claims 1 to 4.

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