Picking and baking method for reducing mechanical damage to tobacco leaves

Abstract

The invention discloses a picking and baking method for reducing mechanical damage of tobacco leaves. The method comprises the following steps: S1, reducing mechanical damage of fresh tobacco leaves; s2, properly densifying and loading the cigarettes; and S3, baking: slowing down the temperature rise speed of the dry-bulb temperature of 36-45 DEG C, slowing down the water loss drying speed of the tobacco leaves at the dry-bulb temperature of 40 DEG C after ignition, properly prolonging the temperature rise and stable temperature baking time of the dry-bulb temperature of 37-40 DEG C and 42-45 DEG C, properly improving the yellowing degree of mechanically damaged tobacco leaves, especially tobacco leaf base leaf ears, and performing scientific baking by adopting a two-reduction and one-growth baking process. The method has the advantages that the mechanical damage of fresh tobacco leaves is obviously reduced, the proportion of green tobacco in the mechanical damage of the flue-cured tobacco leaves is obviously reduced, and the proportion and the grade structure of orange tobacco are improved.

Description

Technical Field

[0001] The invention relates to a tobacco leaf picking and baking method for reducing mechanical damage to tobacco leaves, and belongs to the technical field of tobacco leaf baking. Background Art

[0002] The uniformity of the quality of the first-cured tobacco leaves is an important factor affecting the grade of tobacco raw materials. Judging from the production situation in recent years, many production areas have caused obvious mechanical losses and green content in the cured tobacco leaves due to improper harvesting and mechanical damage to fresh tobacco leaves, especially the green content at the base of the leaves, which seriously affects the uniformity of the quality of the cured tobacco leaves and reduces the availability of tobacco leaves. The fresh tobacco leaves are poorly mature, the leaf tissue structure is relatively tight, and the looseness is poor. The tobacco leaves are easily broken during harvesting, resulting in obvious green content in the cured tobacco leaves. In addition, arid and rainy climate conditions will also lead to an increase in tobacco leaf breakage and mechanical damage. When picking, transporting and packaging tobacco, rough means can easily cause fresh tobacco leaf cells to rupture, and the water loss at the damaged parts of the leaves is significantly accelerated, especially during the baking process. The abnormal water loss of the damaged leaves leads to accelerated drying of the damaged parts, and the material transformation, especially the degradation of plastid pigments, is terminated prematurely, resulting in obvious green content in the mechanically damaged parts. In addition, the tobacco transport vehicle does not use a shade shed device, which is prone to sunburn, resulting in an increase in mechanical damage and green tobacco at the cured tobacco leaves. In view of the current production status, taking some key technical measures for picking and curing can effectively avoid mechanical damage to fresh tobacco leaves, solve the problem of mechanical damage to fresh tobacco leaves and the increase of green tobacco content in mechanically damaged tobacco leaves after curing, and improve the uniformity and availability of the quality of cured tobacco leaves. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a tobacco leaf harvesting and curing method that reduces mechanical damage to tobacco leaves, so as to at least solve the problems mentioned in the background technology.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] Methods for preventing and controlling mechanical damage to flue-cured tobacco leaves include:

[0006] S1, reduce mechanical damage to fresh tobacco leaves: reduce the degree of breakage and mechanical damage of fresh tobacco leaves by harvesting them at maturity, arranging the harvesting time reasonably, transporting them lightly and weaving and clipping them lightly;

[0007] S2, Increase the density of tobacco loading: Increase the density of tobacco loading in the dense flue-curing room, reduce the dehumidification rate of the flue-curing room and the water loss rate of tobacco leaves, so as to ensure that mechanically damaged tobacco leaves have sufficient time to lose water and turn yellow;

[0008] S3, adopts the two-reduction-one-length baking process for scientific baking: slow down the heating rate of the dry-bulb temperature from 36℃ to 45℃, slow down the water loss and drying rate of the tobacco leaves when ignited to a dry-bulb temperature of 40℃, extend the heating and stable baking time at dry-bulb temperatures of 37℃ to 40℃ and 42℃ to 45℃, and increase the yellowing degree of the ear at the base of the tobacco leaves that have been mechanically damaged.

[0009] The above-mentioned harvesting and curing method for reducing mechanical damage to tobacco leaves is that the mature fresh tobacco leaves harvested in S1 are characterized by obvious chlorosis of the earlobes and loose and soft leaves; when harvesting tobacco leaves, pinch the petiole and avoid harvesting by grasping the base of the tobacco leaves with your hands, and the leaves should be handled with care.

[0010] The above-mentioned harvesting and curing method for reducing mechanical damage to tobacco leaves is that the requirement for reasonably arranging the harvesting time in S1 is that tobacco leaves in arid areas should be harvested with dew, and the harvesting time is from 11 pm to 8 am. A light source should be provided under conditions of no light or dim light, and the fresh tobacco leaves should be transported back to the sorting area before 10 am; tobacco leaves under rainy conditions should be harvested in the afternoon on cloudy or sunny days to reduce the moisture on the surface of the tobacco leaves and prevent them from being exposed to the sun.

[0011] The aforementioned tobacco harvesting and roasting method for reducing mechanical damage to tobacco leaves is that the light transportation in S1 refers to the use of soft packaging materials or open tobacco transportation devices to reduce excessive squeezing or irregular operation of fresh tobacco leaves, avoid the phenomenon of scattered stacking of fresh tobacco leaves, and the tobacco transport vehicle uses a shade shed device to avoid the occurrence of sunburn.

[0012] The aforementioned tobacco picking and roasting method for reducing mechanical damage to tobacco leaves is that the lightly braided and clamped tobacco in S1 means that the tobacco should be handled with care during the braiding and clamping process, mainly using the thumb, index finger and middle finger, and never grasped with hands.

[0013] The above-mentioned tobacco leaf harvesting and curing method for reducing mechanical damage is that the standard of the increased density loading in S2 is that the loading capacity of each standard dense curing room on three floors is between 360 and 390 rods / clip, which is 10% to 20% higher than the conventional loading capacity of non-standard dense curing rooms.

[0014] The above-mentioned tobacco leaf harvesting and baking method for reducing mechanical damage is that the operation steps of scientific baking using the two-reduction-one-length baking process in S3 are as follows:

[0015] S3-1, yellowing stage: after ignition, the dry-bulb temperature is raised to 34-36°C at a rate of 1°C / h, with a dry-bulb-wet-bulb temperature difference of 0.5-1°C, and the leaves are baked at a steady temperature for 3-5h until the high-temperature layer turns 10% yellow; then, the dry-bulb temperature is raised to 37-38°C at a rate of 1°C / 2-3h, with a dry-bulb-wet-bulb temperature difference of 0.5-1°C, and the leaves are baked at a steady temperature for 20-35h until the high-temperature layer turns 60% to 70% yellow; then, the dry-bulb temperature is raised to 100% at a rate of 1°C / 3-4h, with a dry-bulb-wet-bulb temperature difference of 0.5-1°C, and the leaves are baked at a steady temperature for 20-35h until the high-temperature layer turns 60% to 70% yellow; 40℃, dry-bulb-wet-bulb temperature difference is 2℃~2.5℃, and the temperature is kept constant for 6~10h; then, the dry-bulb temperature is kept constant, the dry-bulb-wet-bulb temperature difference is increased appropriately to 3℃~4℃, and the temperature is kept constant until the high-temperature layer tobacco leaves turn 80% to 90% yellow; then, the dry-bulb temperature is increased to 42℃ at a rate of 1℃ / 3~5h, the dry-bulb-wet-bulb temperature difference is increased to 5℃~7℃, and the temperature is kept constant for 3~5h, and the temperature is kept constant until the high-temperature layer tobacco leaves turn yellow and blue, and the mechanically damaged parts at the base of the leaves basically turn green;

[0016] S3-2, color fixing period: raise the dry bulb temperature to 45℃ at a rate of 1℃ / 6~8h, increase the dry bulb-wet bulb temperature difference to 8℃~9℃, appropriately extend the steady temperature baking time by 4~6h, and bake at a steady temperature until the base of the whole kang tobacco leaves, including the mechanically damaged leaves, turn yellow and the tips of the leaves curl; then, raise the dry bulb temperature to 48℃ at a rate of 1℃ / 2h, increase the dry bulb-wet bulb temperature difference to 10℃~11℃, and bake at a steady temperature until the whole kang tobacco leaves are dry by more than 1 / 2; then, raise the dry bulb temperature to 53℃~54℃ at a rate of 1℃ / 2h, increase the dry bulb-wet bulb temperature difference to 14℃~16℃, and bake at a steady temperature for 10~20h, until the whole kang tobacco leaves are completely dry;

[0017] S3-3, drying period: raise the dry-bulb temperature to 60℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 20℃~21℃, and bake at a steady temperature for 3~5h; thereafter, raise the dry-bulb temperature to 65℃~67℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 25℃~28℃, and bake at a steady temperature for 20~25h, until the tobacco leaves are completely dry.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] The present invention can ensure that the fresh tobacco leaves have certain softness and elasticity, reduce the degree of mechanical damage and breakage of the fresh tobacco leaves, and thus reduce the proportion of mechanically damaged green tobacco leaves after baking and improve the appearance quality of the tobacco leaves after baking by properly increasing the density of tobacco loading in the dense flue-curing room, increasing the ventilation and dehumidification resistance of the flue-curing room to a certain extent, and reasonably reducing the dehumidification speed of the flue-curing room and the water loss speed of the tobacco leaves, so as to ensure that the mechanically damaged leaves have sufficient time to turn yellow. Thirdly, in terms of baking process, by slowing down the heating rate of dry-bulb temperature from 36℃ to 45℃, slowing down the water loss and drying rate of tobacco leaves when ignited to dry-bulb temperature of 40℃, appropriately extending the heating and stable baking time of dry-bulb temperature from 37℃ to 40℃ and 42℃ to 45℃, appropriately increasing the yellowing degree of mechanically damaged tobacco leaves, especially the earlobes at the base of tobacco leaves, to a certain extent prolonging the yellowing time of mechanically damaged leaves, slowing down the water loss and drying process of mechanically damaged leaves, ensuring that mechanically damaged tobacco leaves have sufficient environmental conditions to turn yellow and fix color, thereby improving the appearance quality and grade structure of the baked tobacco leaves.

[0020] The following advantages can be clearly seen by comparing the tobacco leaf harvesting and curing method of the present invention with the conventional harvesting and curing method:

[0021] 1. Significantly reduce the mechanical damage of fresh tobacco leaves;

[0022] 2. Significantly improve the appearance color of flue-cured tobacco leaves, significantly reduce the proportion of mechanically damaged tobacco leaves and green tobacco, and increase the proportion of orange tobacco;

[0023] 3. Significantly improve the grade structure of flue-cured tobacco leaves.

[0024] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description.

[0025] Instruction Manual

[0026] Figure 1 A photo of tobacco leaves after being roasted using the roasting method of the present invention;

[0027] Figure 2 This is a second photo of tobacco leaves after being roasted using the harvesting and roasting method of the present invention;

[0028] Figure 3 This is the third photo of tobacco leaves after being roasted using the roasting method of the present invention;

[0029] Figure 4 This is a photo of tobacco leaves after being cured using a conventional curing process;

[0030] Figure 5 This is the second photo of tobacco leaves after being cured using the conventional curing process;

[0031] Figure 6 This is the third photo of tobacco leaves after being baked using conventional baking technology. DETAILED DESCRIPTION

[0032] The following will be combined with the tables in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1. A tobacco leaf harvesting and curing method for reducing mechanical damage to tobacco leaves, comprising:

[0034] S1. Reduce the mechanical damage of fresh tobacco leaves: Reduce the degree of damage and mechanical damage of fresh tobacco leaves by harvesting them when they are mature, arranging the harvesting time reasonably, transporting them lightly and weaving them lightly; the characteristic of harvested mature fresh tobacco leaves is that the ear of the leaves is obviously chlorotic and the leaves are loose and soft; when harvesting tobacco leaves, pinch the petiole and avoid harvesting by holding the base of the leaves with your hands, and the leaves should be handled with care; the requirement for arranging the harvesting time reasonably is that tobacco leaves in arid areas should be harvested with dew, and the harvesting time should be from 11 pm to 8 am. In the absence of light or dim light, a light source should be provided, and the fresh tobacco leaves should be transported back to the weaving area before 10 am; tobacco leaves in rainy conditions should be harvested in the afternoon on cloudy or sunny days to reduce the moisture on the surface of the tobacco leaves and prevent them from being exposed to the sun; light transportation refers to the use of soft packaging or open tobacco transportation devices to reduce excessive squeezing or irregular operation of fresh tobacco leaves, avoid the phenomenon of scattered stacking of fresh tobacco leaves, and use shade shed devices on tobacco transport vehicles to avoid sunburn. Lightly holding cigarettes means that you should hold and clip cigarettes gently, mainly with your thumb, index finger and middle finger, and never hold them with your hands;

[0035] S2, increased density of tobacco loading: increase the density of tobacco loading in the dense flue-curing barn, reduce the dehumidification rate of the flue-curing barn and the water loss rate of tobacco leaves, so as to ensure that the mechanically damaged tobacco leaves have sufficient time to lose water and turn yellow; the standard for increased density of tobacco loading is 360 rods / clip for each three-layer standard dense flue-curing barn, and the conventional tobacco loading capacity of the standard dense flue-curing barn is increased by 10%;

[0036] S3, adopts the two-reduction-one-length baking process for scientific baking: slow down the heating rate of the dry-bulb temperature from 36℃ to 45℃, slow down the water loss and drying rate of the tobacco leaves when ignited to a dry-bulb temperature of 40℃, extend the heating and stable baking time at dry-bulb temperatures of 37℃ to 40℃ and 42℃ to 45℃, and increase the yellowing degree of the ear at the base of the tobacco leaves that have been mechanically damaged.

[0037] The operation steps of scientific baking by two minus one length baking process are as follows:

[0038] S3-1, yellowing stage: after ignition, the dry-bulb temperature is raised to 34°C at a rate of 1°C / h, with a dry-bulb and wet-bulb temperature difference of 0.5°C, and the temperature is kept constant for 5 hours until the high-temperature layer of tobacco leaves turns 10% yellow; then, the dry-bulb temperature is raised to 37°C at a rate of 1°C / 2-3h, with a dry-bulb and wet-bulb temperature difference of 0.5°C, and the temperature is kept constant for 35 hours until the high-temperature layer of tobacco leaves turns 60% to 70% yellow; then, the dry-bulb temperature is raised to 40°C at a rate of 1°C / 3-4h , the dry-bulb and wet-bulb temperature difference is 2.5℃, and the temperature is kept constant for 10 hours; after that, the dry-bulb temperature is kept constant, the dry-bulb and wet-bulb temperature difference is appropriately increased to 3℃, and the temperature is kept constant until the high-temperature layer tobacco leaves turn 80% to 90% yellow; after that, the dry-bulb temperature is increased to 42℃ at a rate of 1℃ / 3~5h, the dry-bulb and wet-bulb temperature difference is increased to 5℃, and the temperature is kept constant for 5 hours, and the high-temperature layer tobacco leaves turn yellow and blue, and the mechanically damaged parts at the base of the leaves basically turn green;

[0039] S3-2, color fixation period: raise the dry-bulb temperature to 45°C at a rate of 1°C / 6-8h, increase the dry-bulb-wet-bulb temperature difference to 8°C, appropriately extend the steady-temperature baking time for 6h, and bake at a steady temperature until the base of the tobacco leaves on the whole kang, including the mechanically damaged leaves, turn yellow and the tips of the leaves curl; then, raise the dry-bulb temperature to 48°C at a rate of 1°C / 2h, increase the dry-bulb-wet-bulb temperature difference to 10°C, and bake at a steady temperature until the tobacco leaves on the whole kang are more than 1 / 2 dry; then, raise the dry-bulb temperature to 53°C at a rate of 1°C / 2h, increase the dry-bulb-wet-bulb temperature difference to 14°C, and bake at a steady temperature for 20h, until the tobacco leaves on the whole kang are completely dry;

[0040] S3-3, drying period: raise the dry-bulb temperature to 60℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 20℃, and bake at a steady temperature for 5h; then, raise the dry-bulb temperature to 67℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 28℃, and bake at a steady temperature for 25h, until the tobacco leaves are completely dry.

[0041] Example 2. A tobacco leaf harvesting and curing method for reducing mechanical damage:

[0042] S1. Reduce the mechanical damage of fresh tobacco leaves: Reduce the degree of damage and mechanical damage of fresh tobacco leaves by harvesting them when they are mature, arranging the harvesting time reasonably, transporting them lightly and weaving them lightly; the characteristic of harvested mature fresh tobacco leaves is that the ear of the leaves is obviously chlorotic and the leaves are loose and soft; when harvesting tobacco leaves, pinch the petiole and avoid harvesting by holding the base of the leaves with your hands, and the leaves should be handled with care; the requirement for arranging the harvesting time reasonably is that tobacco leaves in arid areas should be harvested with dew, and the harvesting time should be from 11 pm to 8 am. In the absence of light or dim light, a light source should be provided, and the fresh tobacco leaves should be transported back to the weaving area before 10 am; tobacco leaves in rainy conditions should be harvested in the afternoon on cloudy or sunny days to reduce the moisture on the surface of the tobacco leaves and prevent them from being exposed to the sun; light transportation refers to the use of soft packaging or open tobacco transportation devices to reduce excessive squeezing or irregular operation of fresh tobacco leaves, avoid the phenomenon of scattered stacking of fresh tobacco leaves, and use shade shed devices on tobacco transport vehicles to avoid sunburn. Lightly holding cigarettes means that you should hold and clip cigarettes gently, mainly with your thumb, index finger and middle finger, and never hold them with your hands;

[0043] S2, increased density of tobacco loading: increase the density of tobacco loading in the dense flue-curing barn, reduce the moisture removal rate of the flue-curing barn and the water loss rate of tobacco leaves, so as to ensure that the mechanically damaged tobacco leaves have sufficient time to lose water and turn yellow; the standard for increased density of tobacco loading is 330-375 rods / clip for each standard dense flue-curing barn with three layers, which is a 15% increase in the conventional tobacco loading capacity of the standard dense flue-curing barn;

[0044] S3, adopts the two-reduction-one-length baking process for scientific baking: slow down the heating rate of the dry-bulb temperature from 36℃ to 45℃, slow down the water loss and drying rate of the tobacco leaves when ignited to a dry-bulb temperature of 40℃, extend the heating and stable baking time at dry-bulb temperatures of 37℃ to 40℃ and 42℃ to 45℃, and increase the yellowing degree of the ear at the base of the tobacco leaves that have been mechanically damaged.

[0045] The operation steps of scientific baking by two minus one length baking process are as follows:

[0046] S3-1, yellowing stage: after ignition, the dry-bulb temperature is raised to 35℃ at a rate of 1℃ / h, the dry-bulb and wet-bulb temperature difference is 0.5℃~1℃, and the temperature is kept constant for 4h until the high-temperature layer tobacco leaves turn 10% yellow; then, the dry-bulb temperature is raised to 37℃ at a rate of 1℃ / 2~3h, the dry-bulb and wet-bulb temperature difference is 0.5℃~1℃, and the temperature is kept constant for 28h until the high-temperature layer tobacco leaves turn 60%~70% yellow; then, the dry-bulb temperature is raised to 40℃ at a rate of 1℃ / 3~4h , the dry-bulb and wet-bulb temperature difference is 2℃~2.5℃, and the temperature is kept constant for 8h; after that, the dry-bulb temperature is kept constant, the dry-bulb and wet-bulb temperature difference is appropriately increased to 3℃~4℃, and the temperature is kept constant until the high-temperature layer tobacco leaves turn 80% to 90% yellow; after that, the dry-bulb temperature is increased to 42℃ at a rate of 1℃ / 3~5h, the dry-bulb and wet-bulb temperature difference is increased to 6℃, and the temperature is kept constant for 4h, and the high-temperature layer tobacco leaves turn yellow and blue, and the mechanically damaged parts at the base of the leaves basically turn green;

[0047] S3-2, color fixation period: raise the dry-bulb temperature to 45°C at a rate of 1°C / 6-8h, increase the dry-bulb-wet-bulb temperature difference to 8°C, appropriately extend the steady-temperature baking time for 5h, and bake at a steady temperature until the base of the tobacco leaves on the whole kang, including the mechanically damaged leaves, turn yellow and the tips of the leaves curl; then, raise the dry-bulb temperature to 48°C at a rate of 1°C / 2h, increase the dry-bulb-wet-bulb temperature difference to 10°C-11°C, and bake at a steady temperature until the tobacco leaves on the whole kang are more than 1 / 2 dry; then, raise the dry-bulb temperature to 54°C at a rate of 1°C / 2h, increase the dry-bulb-wet-bulb temperature difference to 15°C, and bake at a steady temperature for 15h, until the tobacco leaves on the whole kang are completely dry;

[0048] S3-3, drying period: raise the dry-bulb temperature to 60℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 20℃~21℃, and bake at a steady temperature for 3~5h; then, raise the dry-bulb temperature to 66℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 26℃, and bake at a steady temperature for 22h, until the tobacco leaves are completely dry.

[0049] Example 3. A tobacco leaf harvesting and curing method for reducing mechanical damage:

[0050] S1. Reduce the mechanical damage of fresh tobacco leaves: Reduce the degree of damage and mechanical damage of fresh tobacco leaves by harvesting them when they are mature, arranging the harvesting time reasonably, transporting them lightly and weaving them lightly; the characteristic of harvested mature fresh tobacco leaves is that the ear of the leaves is obviously chlorotic and the leaves are loose and soft; when harvesting tobacco leaves, pinch the petiole and avoid harvesting by holding the base of the leaves with your hands, and the leaves should be handled with care; the requirement for arranging the harvesting time reasonably is that tobacco leaves in arid areas should be harvested with dew, and the harvesting time should be from 11 pm to 8 am. In the absence of light or dim light, a light source should be provided, and the fresh tobacco leaves should be transported back to the weaving area before 10 am; tobacco leaves in rainy conditions should be harvested in the afternoon on cloudy or sunny days to reduce the moisture on the surface of the tobacco leaves and prevent them from being exposed to the sun; light transportation refers to the use of soft packaging or open tobacco transportation devices to reduce excessive squeezing or irregular operation of fresh tobacco leaves, avoid the phenomenon of scattered stacking of fresh tobacco leaves, and use shade shed devices on tobacco transport vehicles to avoid sunburn. Lightly holding cigarettes means that you should hold and clip cigarettes gently, mainly with your thumb, index finger and middle finger, and never hold them with your hands;

[0051] S2, Increased density of tobacco loading: Increase the density of tobacco loading in the dense flue-curing barn, reduce the dehumidification rate of the flue-curing barn and the water loss rate of tobacco leaves, so as to ensure that the mechanically damaged tobacco leaves have sufficient time to lose water and turn yellow; the standard for increased density of tobacco loading is that the tobacco loading capacity of each standard dense flue-curing barn on three floors is between 390 rods / clip, and the increase is 20% for non-standard dense flue-curing barns;

[0052] S3, adopts the two-reduction-one-length baking process for scientific baking: slow down the heating rate of the dry-bulb temperature from 36℃ to 45℃, slow down the water loss and drying rate of the tobacco leaves when ignited to a dry-bulb temperature of 40℃, extend the heating and stable baking time at dry-bulb temperatures of 37℃ to 40℃ and 42℃ to 45℃, and increase the yellowing degree of the ear at the base of the tobacco leaves that have been mechanically damaged.

[0053] The operation steps of scientific baking by two minus one length baking process are as follows:

[0054] S3-1, yellowing stage: after ignition, the dry-bulb temperature is raised to 36°C at a rate of 1°C / h, the dry-bulb-wet-bulb temperature difference is 1°C, and the leaves are baked at a steady temperature for 3 hours until the high-temperature layer of tobacco leaves turn 10% yellow; then, the dry-bulb temperature is raised to 38°C at a rate of 1°C / 2-3h, the dry-bulb-wet-bulb temperature difference is 1°C, and the leaves are baked at a steady temperature for 20 hours until the high-temperature layer of tobacco leaves turn 60% to 70% yellow; then, the dry-bulb temperature is raised to 40°C at a rate of 1°C / 3-4h, the dry-bulb-wet-bulb temperature difference is 2.5°C, and the leaves are baked at a steady temperature for 6 hours; then, the dry-bulb temperature is controlled unchanged, the dry-bulb-wet-bulb temperature difference is appropriately increased to 4°C, and the leaves are baked at a steady temperature until the high-temperature layer of tobacco leaves turn 80% to 90% yellow; then, the dry-bulb temperature is raised to 42°C at a rate of 1°C / 3-5h, the dry-bulb-wet-bulb temperature difference is increased to 7°C, the baking time is appropriately extended for 3 hours, and the leaves are baked at a steady temperature until the yellow leaves and blue veins of the high-temperature layer of tobacco leaves turn yellow, and the mechanically damaged parts of the leaf base basically turn green;

[0055] S3-2, color fixation period: raise the dry-bulb temperature to 45°C at a rate of 1°C / 6-8h, increase the dry-bulb-wet-bulb temperature difference to 9°C, appropriately extend the steady-temperature baking time by 4h, and bake at a steady temperature until the base of the tobacco leaves on the whole kang, including the mechanically damaged leaves, turn yellow and the tips of the leaves curl; then, raise the dry-bulb temperature to 48°C at a rate of 1°C / 2h, increase the dry-bulb-wet-bulb temperature difference to 11°C, and bake at a steady temperature until the tobacco leaves on the whole kang are more than 1 / 2 dry; then, raise the dry-bulb temperature to 54°C at a rate of 1°C / 2h, increase the dry-bulb-wet-bulb temperature difference to 16°C, and bake at a steady temperature for 10h, until the tobacco leaves on the whole kang are completely dry;

[0056] S3-3, drying period: raise the dry-bulb temperature to 60℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 21℃, and bake at a steady temperature for 3h; then, raise the dry-bulb temperature to 67℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 28℃, and bake at a steady temperature for 20h, until the tobacco leaves are completely dry.

[0057] The tobacco leaf picking and curing method in the embodiment is compared with the conventional picking and curing method. Figure 1-Figure 3 and Figure 4-Figure 6 As shown, it can be seen that 1. the appearance color of the flue-cured tobacco leaves is significantly improved, the proportion of mechanically damaged tobacco leaves and green tobacco is significantly reduced, and the proportion of orange tobacco is increased; 2. the grade structure of the flue-cured tobacco leaves is significantly improved. At the same time, the proportion of mechanically damaged fresh tobacco leaves in the middle after braiding was counted, and the appearance quality and grade structure of the flue-cured middle tobacco leaves were tested and compared. The results are shown in Tables 1 and 2.

[0058] Table 1 Effects of different treatments on mechanical damage of fresh tobacco leaves

[0059]

[0060] Table 2 Effects of different treatments on the appearance quality of flue-cured tobacco leaves

[0061]

[0062] Table 3 Effects of different treatments on grade structure and proportion of green tobacco in mechanically damaged tobacco leaves after flue-cured

[0063]

[0064] Note: Different lowercase letters indicate significant differences among treatments.

[0065] Tables 1 to 3 show the analytical data obtained by the method of the present invention. The results show that the harvesting and curing method of the present invention can significantly reduce the mechanical damage of fresh tobacco leaves, improve the appearance quality of cured tobacco leaves, and significantly increase the proportion of orange-yellow tobacco leaves and the grade structure after curing.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A tobacco leaf harvesting and curing method for reducing mechanical damage to tobacco leaves, characterized in that: include: S1, reduce mechanical damage to fresh tobacco leaves: reduce the degree of breakage and mechanical damage of fresh tobacco leaves by harvesting them at maturity, arranging the harvesting time reasonably, transporting them lightly and weaving and clipping them lightly; S2, Increase the density of tobacco loading: Increase the density of tobacco loading in the dense flue-curing room, reduce the dehumidification rate of the flue-curing room and the water loss rate of tobacco leaves, so as to ensure that mechanically damaged tobacco leaves have sufficient time to lose water and turn yellow; S3, adopts two reduction and one extension baking process for scientific baking: slow down the heating rate of dry bulb temperature from 36℃ to 45℃, slow down the water loss and drying rate of tobacco leaves when ignited to dry bulb temperature of 40℃, extend the heating and stable baking time of dry bulb temperature from 37℃ to 40℃ and 42℃ to 45℃, increase the yellowing degree of leaf ears at the base of mechanically damaged tobacco leaves, thereby reducing the proportion of green tobacco in mechanically damaged tobacco leaves after baking, and increasing the proportion of orange-yellow tobacco and grade structure.

2. The method for harvesting and curing tobacco leaves to reduce mechanical damage according to claim 1, characterized in that: The characteristic features of the mature fresh tobacco leaves harvested in S1 are that the earlobes are obviously chlorotic and the leaves are loose and soft. When harvesting tobacco leaves, pinch the petiole and avoid holding the base of the leaves with your hands. The leaves should be handled with care.

3. The method for harvesting and curing tobacco leaves to reduce mechanical damage according to claim 1, characterized in that: The requirement for reasonably arranging the harvesting time in S1 is that tobacco leaves in arid areas should be harvested with dew, and the harvesting time should be between 11 pm and 8 am. In the absence of light or dim light, a light source should be provided, and the fresh tobacco leaves should be transported back to the sorting area before 10 am. Tobacco leaves in rainy conditions should be harvested in the afternoon on cloudy or sunny days to reduce the moisture on the surface of the tobacco leaves and prevent them from being exposed to the sun.

4. The method for harvesting and curing tobacco leaves to reduce mechanical damage according to claim 1, characterized in that: The light transportation in S1 refers to the use of soft packaging or open tobacco transportation devices to reduce excessive squeezing or irregular operation of fresh tobacco leaves, avoid the phenomenon of scattered stacking of fresh tobacco leaves, and use of shade shed devices on tobacco transport vehicles to avoid the occurrence of sunburns.

5. The method for harvesting and curing tobacco leaves to reduce mechanical damage according to claim 1, characterized in that: The light clamping of cigarettes in S1 means that the cigarettes should be handled with care during the clamping process, mainly using the thumb, index finger and middle finger, and should not be grasped by hand.

6. The method for harvesting and curing tobacco leaves to reduce mechanical damage according to claim 1, characterized in that: The standard for increased smoke loading in S2 is that the smoke loading capacity of each standard dense curing room on three floors is between 360 and 390 rods / clip, which is 10% to 20% higher than the conventional smoke loading capacity of non-standard dense curing room.

7. The method for harvesting and curing tobacco leaves to reduce mechanical damage according to claim 1, characterized in that: The operation steps of scientific baking using the two-reduction-one-length baking process in S3 are as follows: S3-1, yellowing period: after ignition, raise the dry-bulb temperature to 34~36℃ at a rate of 1℃ / h, with a dry-bulb-wet-bulb temperature difference of 0.5℃~1℃, and bake at a steady temperature for 3~5 hours until the tobacco leaves in the high-temperature layer turn 10% yellow; then, raise the dry-bulb temperature to 37~38℃ at a rate of 1℃ / 2~3 h, with a dry-bulb-wet-bulb temperature difference of 0.5℃~1℃, and bake at a steady temperature for 20~35 hours until the tobacco leaves in the high-temperature layer turn 60%~70% yellow; then, raise the dry-bulb temperature to 40℃ at a rate of 1℃ / 3~4 h, with a dry-bulb-wet-bulb temperature difference of 2℃~2.5℃, and bake at a steady temperature for 6~10 hours; then, control the dry-bulb temperature unchanged, appropriately increase the dry-bulb-wet-bulb temperature difference to 3℃~4℃, and bake at a steady temperature until the tobacco leaves in the high-temperature layer turn 80%~90% yellow; then, raise the dry-bulb temperature to 40℃ at a rate of 1℃ / 3~4 h, with a dry-bulb-wet-bulb temperature difference of 2℃~2.5℃, and bake at a steady temperature for 6~10 hours. h, increase the dry-bulb temperature to 42°C, increase the dry-bulb and wet-bulb temperature difference to 5°C~7°C, appropriately extend the steady-temperature baking time by 3~5 h, and bake at a steady temperature until the high-temperature layer of tobacco leaves have yellow leaves and blue veins, and the mechanically damaged parts of the leaf base have basically turned green; S3-2, color fixation period: increase the dry-bulb temperature to 45℃ at a rate of 1℃ / 6~8h, increase the dry-bulb and wet-bulb temperature difference to 8℃~9℃, appropriately extend the steady-temperature baking time by 4~6h, and bake at a steady temperature until the base of the tobacco leaves on the whole kang, including the mechanically damaged leaves, turn yellow and the tips of the leaves curl; then, increase the dry-bulb temperature to 48℃ at a rate of 1℃ / 2h, increase the dry-bulb and wet-bulb temperature difference to 10℃~11℃, and bake at a steady temperature until the tobacco leaves on the whole kang are more than 1 / 2 dry; then, increase the dry-bulb temperature to 53℃~54℃ at a rate of 1℃ / 2h, increase the dry-bulb and wet-bulb temperature difference to 14℃~16℃, and bake at a steady temperature for 10~20h, until the tobacco leaves on the whole kang are completely dry; S3-3, drying period: raise the dry-bulb temperature to 60℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 20℃~21℃, and bake at a steady temperature for 3~5 hours; thereafter, raise the dry-bulb temperature to 65℃~67℃ at a heating rate of 1℃ / h, increase the dry-bulb-wet-bulb temperature difference to 25℃~28℃, and bake at a steady temperature for 20~25 hours, until the tobacco leaves on the kang are completely dry.

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