A process for baking tobacco leaves fresh and bright

Abstract

The invention discloses a tobacco leaf fresh-baking and bright-baking process, comprising the following steps: harvesting and packaging tobacco leaves according to normal maturity, closing the door of the baking room, not starting the equipment, and keeping the door on the stove for 12-16 hours until the leaves are basically fresh; slowly raising the temperature of the baking room to 33°C with a small fire, maintaining the wet-bulb temperature at 32°C, and keeping the temperature steady for 2 hours; raising the temperature to 37°C at a rate of 1°C per hour, controlling the wet-bulb temperature at 36°C, and keeping the temperature steady for 8-12 hours; raising the temperature to 39°C at a rate of 1°C / 2h, maintaining .... To 41℃, wet bulb temperature 36℃, keep temperature steady for 8-12h; increase temperature to 43℃, wet bulb temperature 36℃, keep temperature steady for 8-12h; increase temperature to 49℃, wet bulb temperature 38℃, keep temperature steady for 6-10h; increase temperature to 53℃, wet bulb temperature 39℃, keep temperature steady for 6h; increase temperature to 67℃, wet bulb temperature 40℃, keep temperature steady for 12h; decrease temperature to 65℃, wet bulb temperature 40℃, keep temperature steady for 12h, and bake and dry the tobacco leaves with aroma preservation, so as to achieve the purpose of baking fresh and bright tobacco leaves.

Description

Technical Field

[0001] The invention relates to a tobacco leaf fresh baking and bright baking process, belonging to the technical field of tobacco leaf baking. Background Art

[0002] Tobacco leaf baking and curing, as the last link in tobacco leaf production, plays a decisive role in tobacco leaf quality. At present, the control of tobacco leaf baking quality is still an important link and means to control tobacco leaf baking losses and improve tobacco leaf economic benefits and quality. The appearance of tobacco leaves is the primary manifestation of tobacco leaf economic benefits, and baking freshness and brightness are the direct manifestations of tobacco leaf appearance quality. From the perspective of tobacco leaf appearance, the main problems of existing tobacco leaf baking are as follows: (1) Due to the relatively insufficient accumulation of dry matter in the lower tobacco leaves, the existing baking process often causes excessive yellowing of tobacco leaves, excessive consumption of dry matter in tobacco leaves, and the phenomenon of starvation and ash or bad tobacco, which greatly reduces the appearance quality and usability of tobacco leaves; (2) Due to the compact cell structure and rich accumulation of dry matter in the middle and upper tobacco leaves, the existing baking process is often difficult to control the coordination of yellowing and water loss of tobacco leaves, and it is easy for the water loss rate to fail to keep up with the yellowing rate. It is easy for strong moisture removal to cause tobacco leaf cell rupture and browning reaction, resulting in the phenomenon of ash hanging in the middle and upper tobacco leaves, which reduces the appearance quality and usability of tobacco leaves; (3) The existing baking process is prone to long-term low temperature and high humidity conditions, and some pathogens brought by tobacco leaves from the field are very easy to grow under low temperature and high humidity conditions, forming tobacco leaf mildew, which greatly reduces the baking quality and usability of tobacco leaves. The above three situations all affect the "freshness" and "brightness" of the first-baked tobacco leaves. It is necessary to study and improve this. Summary of the invention

[0003] Based on the above, the present invention provides a tobacco leaf fresh-baking and bright-baking process that can improve the appearance quality of tobacco leaves, so as to overcome the shortcomings of the existing baking process.

[0004] The technical solution of the present invention is: a tobacco leaf fresh-baking and bright-baking process, comprising the following steps:

[0005] Step S1, harvesting and packaging tobacco leaves according to normal maturity, closing the door of the drying room, not turning on the equipment, and keeping the room in a humid environment for 12-16 hours until the leaves are basically fresh again;

[0006] Step S2, slowly raise the temperature of the baking room to 33°C with a low fire, maintain the wet bulb temperature at 32°C, and keep the temperature steady for 2 hours for preheating;

[0007] Step S3, raising the dry bulb temperature to 37°C at a rate of 1°C per hour, controlling the wet bulb temperature at 36°C, and maintaining the temperature and moisture retention for 8-12 hours, so that the tobacco leaves turn yellow to 40% to 50%;

[0008] Step S4, raising the dry bulb temperature to 39°C and the wet bulb temperature to 36°C at a rate of 1°C / 2h, and baking at a constant temperature for 8-12h to make the tobacco leaves turn yellow to 70% to 80%;

[0009] Step S5, raising the dry bulb temperature to 41°C and the wet bulb temperature to 36°C at a rate of 1°C / 2h, and baking at a constant temperature for 8-12h to make the tobacco leaves turn yellow to 80% to 90%;

[0010] Step S6, raising the dry bulb temperature to 43°C and the wet bulb temperature to 36°C at a rate of 1°C / 2h, and baking at a constant temperature for 8-12h, until the tobacco leaves are 90% yellow, and the main and secondary branch veins are still green;

[0011] Step S7, raising the dry bulb temperature to 49°C and the wet bulb temperature to 38°C at a rate of 1°C / 2h, and baking at a constant temperature for 6-10h to whiten the main tendons of the tobacco leaves;

[0012] Step S8, raising the dry bulb temperature to 53°C and the wet bulb temperature to 39°C at a rate of 1°C / 2h, and baking at a constant temperature for 6h, so that the tobacco leaves are 90% dry, the main tendons with poor maturity are 20-30% still green, and the oil and aroma are increased;

[0013] Step S9, raising the dry bulb temperature to 67°C and the wet bulb temperature to 40°C at a rate of 1°C / 1h, baking at a constant temperature for 12h, and rapid fire-curing, so that the main tendons and branch veins of the tobacco leaves all turn yellow;

[0014] Step S10, cool the dry bulb temperature to 65°C and the wet bulb temperature to 40°C at 1°C / 6h, and bake and dry until the aroma is preserved.

[0015] Preferably, in step S2, the time for keeping the kang warm is from the night of the tobacco leaf harvesting day to the next morning.

[0016] Preferably, in step S2, when the dry-bulb temperature rises to 37°C and the wet-bulb temperature is less than 36°C, the fan is stopped for two hours, and after the humidity rises to 36°C, baking is resumed, and the wet-bulb temperature remains unchanged.

[0017] Preferably, in step S8, when the main ribs of the poorly mature tobacco leaves are still 20-30% green, do not extend the temperature stabilization time and the temperature rise time to avoid failing to achieve the purpose of rapid fire killing.

[0018] The working principle of the present invention is as follows: the tobacco leaves are harvested on the same day, and after harvesting, weaving and going to a kang, due to artificial touch, some mechanical damage is generated, and after experiencing the influence of the high temperature of the day, most of the tobacco leaves' stomata are closed, and the leaves wilt, which is not conducive to water loss and yellowing. After a period of time (especially at night) of natural reduction on a stuffy kang, the tobacco leaves' stomata gradually open, normal respiration and metabolism are restored, cell activity gradually recovers, and some cells with less mechanical damage can also restore normal functions. The tobacco leaf cells are in a very fresh state, which is conducive to cell respiration metabolism and physiological and biochemical reactions, and is conducive to yellowing and water loss of the tobacco leaves. And in the yellowing stage of the tobacco leaves, the yellowing temperature (steps S4, S5, S6) is appropriately increased, the humidity is steadily controlled, the probability of tobacco leaves going moldy is reduced, the yellowing speed of the tobacco leaves is accelerated, and the water loss speed is gradually controlled at the same time, so as to achieve yellowing and water loss coordination and synchronization. On the basis of the coordination of yellowing and water loss of tobacco leaves, the temperature of tobacco leaf gluten change is directly increased to 49°C (conventionally 45°C) to improve the efficiency of gluten change, accelerate color fixation, effectively avoid excessive ash and yellowing, and promote the formation of small molecular substances in tobacco leaves. In the tobacco leaf dry gluten stage, the rapid fire is used to kill the green, which can accelerate the yellowing efficiency of the main veins of tobacco leaves on the one hand, and reduce the loss of tobacco aroma substances on the other hand. Then the temperature of tobacco leaf dry gluten will be appropriately lowered to 65°C, which has the effect of preserving fragrance. On the basis of ensuring the freshness and brightness of tobacco leaves, it is also conducive to aroma preservation and baking. In summary, the freshness of tobacco leaves on the kang lays the foundation for the subsequent accelerated yellowing and water loss, the coordinated synchronization of yellowing and water loss, and the absence of excessive consumption after 49°C. The coordinated synchronization of yellowing and water loss completed at 43°C makes it possible to directly increase the temperature to 49°C for baking in the future, thereby preventing excessive ash and yellowing. It can be seen that through the coordination of the above-mentioned means, the purpose of baking fresh and bright tobacco leaves is finally achieved.

[0019] Compared with the prior art, the advantages of the present invention are: 1. Avoiding excessive yellowing, reducing the proportion of ash and bad leaves in the lower tobacco leaves, and making the tobacco leaves brighter in color. 2. Dehumidifying in sequence to avoid large-scale dehumidification, reduce the risk of cell rupture, and reduce color reactions such as ash in the middle and upper tobacco leaves. 3. Properly increase the yellowing temperature of tobacco leaves, shorten the low-temperature yellowing time (low temperature and high humidity time before 38°), reduce the probability of tobacco leaf mildew, and improve the economic benefits of tobacco leaves. 4. Using high temperature and high humidity to fix the color, the branch veins are not easy to contain green, and the leaves are not easy to be slightly green. 5. Using low-temperature drying in the later stage of drying is easy to regain moisture and preserve fragrance, and the leaves are soft and bright. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation of the present invention is described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0021] Example 1: Control effect on the ratio of lower tobacco leaf dregs

[0022] The verification test was conducted in Qianxi County, Guizhou Province in 2022, and the test flue-cured tobacco variety was the lower leaves of Yunyan 87. The test tobacco leaves were cultivated and managed in accordance with the standardized production of local high-quality tobacco leaves, and harvested according to conventional maturity standards and processes. The test flue-curing room was a standard intensive large flue-curing room.

[0023] 1.1 Experimental design

[0024] A comparative experiment was carried out using the local conventional baking process as a control and the fragrant and bright baking process of the present invention as a comparative treatment.

[0025] Table 1-1 Experimental design Unit: ℃, h

[0026]

[0027]

[0028] 1.2 Results of classification and evaluation of flue-cured tobacco leaves

[0029] Two flue-curing rooms respectively took 10 tobacco rods from the same position in the tobacco room, and classified the newly-cured tobacco leaves into bad leaves, normal tobacco leaves and flue-cured green tobacco, and counted their weights. The results showed that the proportion of bad leaves in the newly-cured tobacco leaves of the control flue-curing process was as high as 36.91%, while the proportion of bad leaves in the comparison flue-curing process and the tobacco leaves of the present fresh-baked and bright-baked process was only 4.49%, which was much lower than the control, and the control effect on the bad leaves of tobacco leaves was very obvious.

[0030] Table 1-2 Comparative analysis of baking effects of different baking processes

[0031]

[0032] 1.3 Comparative analysis of the appearance quality of flue-cured tobacco leaves

[0033] For the above comparative verification test, normal tobacco leaves were selected and the appearance quality of the cured tobacco leaves X2F was identified according to the national standard GB2635-1992. The results are shown in Table 1-3.

[0034] Table 1-3 Effect of baking process on the appearance quality of lower tobacco leaves

[0035] Judging Project Control process Comparison process Color / value Orange(8.0) Orange(8.5) Maturity / score Mature (7.5) Mature (7.5) Structure / score Loose (7.5) Loose (7.5) Identity / score Slightly thin (5.5) Slightly thin (6.0) Oil content / value Slightly (4.0) Slightly (4.5) Chroma / score Medium - (5.0) Medium (5.0) Total score 37.5 39.0

[0036] It can be seen from the above table that even for the same normal tobacco leaves, there are differences in the appearance quality of the tobacco leaves after the two baking processes. The color, identity, oil content and chroma of the tobacco leaves after baking by the comparison process are slightly better than those of the control process. Therefore, it can be said that the appearance quality of the tobacco leaves after baking by the comparison process is better than that of the control process.

[0037] Example 2: Control effect on the ash ratio of upper tobacco leaves

[0038] The verification test was conducted in Qianxi County, Guizhou Province in 2021, and the test tobacco variety was the upper leaves of Yunyan 87. The test tobacco leaves were cultivated and managed in accordance with the standardized production of local high-quality tobacco leaves, and harvested according to conventional maturity standards and processes. The test flue-curing room was a standard intensive large flue-curing room.

[0039] 2.1 Experimental design

[0040] A comparative experiment was carried out using the local conventional baking process as a control and the fragrant and bright baking process of the present invention as a comparative treatment.

[0041] Table 2-1 Experimental design Unit: ℃, h

[0042]

[0043] 2.2 Results of classification and evaluation of flue-cured tobacco leaves

[0044] Two flue-curing rooms took 10 tobacco rods from the same position in each room, and classified the newly-cured tobacco leaves into ash-covered leaves (including lightly ash-covered and heavily ash-covered leaves), normal tobacco leaves and green tobacco leaves (including blue veins, green flakes and mechanical damage) and counted their weights. The results showed that the proportion of ash-covered leaves in the newly-cured tobacco leaves of the control flue-curing process was as high as 27.07%, while the proportion of bad flakes in the comparative flue-curing process and the tobacco leaves of the present fresh-baked and bright-baked process was only 5.49%, which was much lower than the control, and the control effect on the ash-covered tobacco leaves was very obvious.

[0045] Table 2-2 Comparative analysis of baking effects of different baking processes

[0046]

[0047]

[0048] 2.3 Comparative analysis of the appearance quality of flue-cured tobacco leaves

[0049] For the above comparative verification test, normal tobacco leaves were selected and the appearance quality of the cured tobacco leaves B2F was identified according to the national standard GB2635-1992. The results are shown in Table 2-3.

[0050] Table 2-3 Effect of baking process on the appearance quality of upper tobacco leaves

[0051] Judging Project Control process Comparison process Color / value Orange(9.5) Orange(9.5) Maturity / score Mature (9.0) Mature (9.0) Structure / score Still loose(7.0) Still loose (7.5) Identity / score Moderate (8.0) Moderate (9.0) Oil content / value More (9.0) More (9.0) Chroma / score Strong - (6.5) Strong - (6.5) Total score 49 50.5

[0052] It can be seen from the above table that even for the same normal tobacco leaves, there are differences in the appearance quality of the tobacco leaves after the two baking processes. The structure and identity of the tobacco leaves after baking by the comparison process are slightly better than those by the control process. Therefore, it can be said that the appearance quality of the tobacco leaves after baking by the comparison process is better than that by the control process.

[0053] 2.4 Comparative analysis of sensory evaluation quality

[0054] Table 2-4. Sensory evaluation of tobacco leaves after flue-cured in Qianxi County in 2021 (upper leaves)

[0055]

[0056] Table 2-4 is a comparative analysis of the sensory smoking quality of two different baking processes. It can be seen that the total score of the sensory smoking quality of tobacco leaves after baking with the comparative baking process reached 71.68 points, which is slightly higher than the sensory smoking quality score of 70.94 of tobacco leaves after baking with the conventional baking process in Qianxi, indicating that the comparative baking process is helpful in improving the sensory quality of tobacco leaves.

[0057] Example 3: Control effect on the incidence of tobacco leaf mildew

[0058] This experiment conducted comparative analysis in a group of tobacco leaf mildew-prone drying rooms throughout the year. By comparing and analyzing the baking process with the control, the incidence of tobacco leaf mildew under different baking processes was statistically analyzed.

[0059] 3.1 Experimental design

[0060] A comparative experiment was carried out using the local conventional baking process as a control and the fragrant and bright baking process of the present invention as a comparative treatment.

[0061] Table 3-1 Experimental design Unit: ℃, h

[0062]

[0063] 3.2 Analysis of tobacco leaf mildew

[0064] Sampling was performed after curing, with one rod being taken at the same interval in each layer, for a total of 10 rods of tobacco leaves. Thirty rods were taken as samples from each curing room. The following table shows the investigation results of tobacco leaf mildew and rot after curing in two treatments.

[0065] Table 3-2 Treatment of tobacco leaf mold after curing with different ozone introduction times

[0066]

[0067] The results of Experimental Example 1 are shown in Table 1. The two process treatments have obvious differences in the prevention and control effects of tobacco leaf mildew. The incidence rate and severity of tobacco leaf mildew after baking treated with this comparative process are significantly lighter than those of the conventional control baking process. The incidence rate of tobacco leaf mildew treated with T1 is 2.96%, and the diseased parts basically only appear within 5 cm of the petiole and leaf base, while the incidence rate of tobacco leaf mildew treated with T2 is 12.23%, and the diseased parts spread to about 10 cm from the leaf base, indicating that the prevention and control effect of T1 treatment on tobacco leaf mildew is significantly better than that of T2, confirming that this baking process has a better control effect on the incidence of tobacco leaf mildew.

[0068] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A tobacco leaf fresh-baking and bright-baking process, characterized in that: The following steps are involved: Step S1, harvesting and packaging tobacco leaves according to normal maturity, closing the door of the drying room, temporarily not turning on the equipment, and keeping the room cool for 12-16 hours to make the leaves basically recover their freshness; Step S2, slowly raise the temperature of the baking room to 33°C with a low fire, maintain the wet bulb temperature at 32°C, and keep the temperature steady for 2 hours for preheating; Step S3, raising the dry bulb temperature to 37°C at a rate of 1°C per hour, controlling the wet bulb temperature at 36°C, and maintaining the temperature and moisture retention for 8-12 hours, so that the tobacco leaves turn yellow to 40% to 50%; Step S4, raising the dry bulb temperature to 39°C and the wet bulb temperature to 36°C at a rate of 1°C / 2h, and baking at a constant temperature for 8-12h to make the tobacco leaves turn yellow to 70% to 80%; Step S5, raising the dry bulb temperature to 41°C and the wet bulb temperature to 36°C at a rate of 1°C / 2h, and baking at a constant temperature for 8-12h to make the tobacco leaves turn yellow to 80% to 90%; Step S6, raising the dry bulb temperature to 43°C and the wet bulb temperature to 36°C at a rate of 1°C / 2h, and baking at a constant temperature for 8-12h, until the tobacco leaves are 90% yellow, and the main and secondary branch veins are still green; Step S7, raising the dry bulb temperature to 49°C and the wet bulb temperature to 38°C at a rate of 1°C / 2h, and baking at a constant temperature for 6-10h to whiten the main tendons of the tobacco leaves; Step S8, raising the dry bulb temperature to 53°C and the wet bulb temperature to 39°C at a rate of 1°C / 2h, and baking at a constant temperature for 6h, so that the tobacco leaves are 90% dry, the main tendons with poor maturity are 20-30% still green, and the oil and aroma are increased; Step S9, raising the dry bulb temperature to 67°C and the wet bulb temperature to 40°C at a rate of 1°C / 1h, baking at a constant temperature for 12h, and rapid fire to make the main tendons and branches of the tobacco leaves turn yellow and enhance the aroma; Step S10, cool the dry bulb temperature to 65°C and the wet bulb temperature to 40°C at 1°C / 6h, and bake and dry until the aroma is preserved.

2. The tobacco leaf fresh-baking and bright-baking process according to claim 1, characterized in that: In step S2, night is selected as the time for sleeping on the kang.

3. The tobacco leaf fresh-baking and bright-baking process according to claim 1, characterized in that: In step S2, when the dry-bulb temperature rises to 37°C and the wet-bulb temperature is less than 36°C, the fan is stopped for two hours and then the baking is resumed, and the wet-bulb temperature remains unchanged.

4. The tobacco leaf fresh-baking and bright-baking process according to claim 1, characterized in that: In step S8, when the main ribs of the poorly mature tobacco leaves are still 20-30% green, do not extend the temperature stabilization time and the temperature rise time to avoid failing to achieve the purpose of rapid fire killing.

Images