A method for curing upper leaves after autumn

Abstract

The application discloses a method for curing upper tobacco leaves after autumn, which improves the maturity and aging degree of the upper tobacco leaves after autumn and the softness of the cured tobacco leaves by stem breaking treatment. The method improves the curing characteristics of the upper tobacco leaves and reduces the proportion of ashed and green tobacco by spraying the nutrition solution of ethylene and potassium dihydrogen phosphate on the leaf surface. The method improves the softness of the cured tobacco leaves and reduces the proportion of green tobacco by fresh tobacco leaf maturity harvesting, reasonable classification and tobacco arrangement, fresh tobacco leaf softening and wilting and yellowing in the tobacco drying room. The method improves the appearance quality and internal quality of the cured tobacco leaves by using low-temperature and moisture slow yellowing curing technology in the early stage of yellowing, low-temperature and low-humidity slow yellowing curing technology in the late stage of yellowing, low-temperature and low-humidity slow heating curing technology in the color fixing stage and low-temperature and low-humidity dry tobacco curing technology in the dry tobacco stage.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of autumn upper tobacco leaf curing method, belong to tobacco curing technical field. BACKGROUND

[0002] Autumn tobacco leaf is mostly developed under dry and cool autumn climate conditions Upper tobacco leaf, less water content in leaf, thick leaf, leaf tissue cell arrangement is compact, and the internal substance is full.Guizhou is a large province of tobacco planting in China, and flue-cured tobacco is one of the important economic crops and sources of revenue in Guizhou.Guizhou is located on the Yunnan-Guizhou Plateau, and the mountainous three-dimensional climate is obvious, with an average elevation of about 1,000 m.In the middle and late September and early October, the harm degree of climate factors such as low temperature frost, increasing day and night temperature difference, autumn wind and autumn rain to upper tobacco leaf is particularly serious in western tobacco-growing areas of Guizhou.Due to the unique geographical location and elevation characteristics of Guizhou, the ecological environmental factors have a significant impact on the maturity and quality formation of tobacco leaves, which easily leads to tight tissue structure of upper tobacco leaves, and the tobacco leaves cannot be normally matured and yellow, the tobacco leaf easy-to-bake property is poor, the baking resistance is general or poor, and the tobacco leaf is prone to be green and gray, and even black, with baking loss reaching more than 30%, which is not conducive to improving the quality and usability of upper tobacco leaves.Therefore, improving the maturity and aging degree of fresh tobacco leaves and improving the baking process are important guarantees for improving the quality of upper tobacco leaves.

[0003] From the current situation, the quality and nutritional conditions of upper tobacco leaves under cold damage conditions are mainly improved by spraying potassium dihydrogen phosphate and sucrose solution (already published patent: Flue-cured tobacco cultivation management and baking method based on potassium dihydrogen phosphate and sucrose to alleviate cold damage;Baking method for reducing low-temperature cold damage loss of Honghuadajinyan tobacco leaves in high-altitude areas), but single increase of spraying potassium dihydrogen phosphate and sucrose solution for tobacco ripening treatment still cannot effectively solve the problems existing in the baking of upper tobacco leaves, so more perfect and systematic processing supporting technical measures for upper tobacco leaves are needed. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a tobacco leaf harvesting and baking method that can improve the maturity, quality and baking consistency of fresh tobacco leaves, improve the appearance quality and internal quality of baked tobacco leaves, and reduce the proportion of gray and green tobacco, which can overcome the shortcomings of the prior art.

[0005] The technical solution of the present application is: an autumn upper tobacco leaf harvesting and baking method, comprising:

[0006] S1, stem breaking: 1-2 days after middle tobacco leaf harvesting, stem breaking treatment is performed at 10-20 cm below 4-6 upper tobacco leaves, the cross section of the stem breaking treatment is 1 / 3-1 / 2 of the stem cross section, to promote the maturity and aging of the upper tobacco leaves;

[0007] S2, spraying leaf surface ripening nutrient solution: using 300-500 times water to dilute 40% ethephon solution, 200-300 times water to dilute potassium dihydrogen phosphate solution, mixing the above two kinds of diluted solutions according to the ratio of 1:1 to spray the leaf surface, spraying 15-20 kg per mu, further coordinating the upper leaf nutrition balance, improving the quality of tobacco leaves, and promoting the maturation of tobacco leaves;

[0008] S3, fresh tobacco leaf harvesting: more than 90% of the harvested fresh tobacco leaves are physiologically mature and technologically mature tobacco leaves, the leaves are mainly green and yellow, the leaf tips are yellow and withered, the leaf edges are yellow, most of the hairs have fallen off, and the main veins are basically white.

[0009] S4, fresh tobacco leaf classification and sorting: according to the maturity, the fresh tobacco leaves are roughly divided into three categories: under-ripe, mature and over-ripe tobacco leaves, and are classified and sorted, with 120-130 leaves per pole.

[0010] S5, fresh tobacco leaf loading: classified and layered, the same layer and the same quality are loaded, the under-ripe tobacco leaves are loaded in the low temperature layer, the over-ripe tobacco leaves are loaded in the high temperature layer, and the mature tobacco leaves are loaded in the other layers, and the loading density is increased by 5%-15% compared with the conventional.

[0011] S6, fresh tobacco leaf softening and wilting and yellowing: after the fresh tobacco leaves are loaded into the curing room, the cold air inlet and the moisture removal window are closed, the circulating fan is started for 2-3 hours, then the circulating fan is turned off for 15-25 hours to keep the temperature and humidity, until the fresh tobacco leaves are slightly soft and wilted, and the tobacco leaves are yellowed by 1-2.

[0012] S7, curing: in the early stage of yellowing, low temperature and humidity slow yellowing curing technology is adopted, in the later stage of yellowing, low temperature and low humidity slow yellowing curing technology is adopted to make the tobacco leaves fully soft and wilted and yellow, in the color fixing period, low temperature and low humidity slow warming color fixing curing technology is adopted to make the yellow color of the tobacco leaves fixed, and in the dry stem period, low temperature and low humidity dry stem curing technology is adopted to dry the tobacco stem.

[0013] The aforementioned tobacco leaf curing method after autumn is, in step S1, the stem breaking treatment is performed in relatively good weather, there is no dew or rain on the surface of the tobacco stem, the tobacco plant is prevented from being infected by diseases, and the cross section of the broken stem is more than 1 / 2.

[0014] The aforementioned tobacco leaf curing method after autumn is, in step S2, the leaf surface ripening nutrient solution is sprayed 1-2 days after the stem breaking treatment, and the spraying is performed in the morning at 9-10 o'clock or in the afternoon at 4-5 o'clock.

[0015] The aforementioned tobacco leaf curing method after autumn is, in step S4, the under-ripe tobacco leaves are the tobacco leaves which are still ripe and the maturity is lower than that of the still ripe tobacco leaves, the mature tobacco leaves are the physiologically mature and technologically mature tobacco leaves, and the over-ripe tobacco leaves are the fresh tobacco leaves which are higher than the technologically mature tobacco leaves in maturity and have the value of curing.

[0016] The aforementioned method for harvesting and curing upper tobacco leaves in autumn involves using a low-temperature, moisturizing, slow-yellowing curing technique in step S7 during the early yellowing stage. This reduces the dry-bulb temperature and heating rate, slows down the dehumidification rate and tobacco leaf drying rate, and extends the low-temperature yellowing time before reaching 38°C, promoting the tobacco leaves to fully soften, wither, and turn yellow. The specific operation is as follows:

[0017] After ignition, the dry bulb temperature is increased to 32℃ and the wet bulb temperature to 31-32℃ at a heating rate of 1℃ / h. The temperature is maintained for 15-20 hours, and the tobacco leaves turn 30-50% yellow. Then, the dry bulb temperature is increased to 35-36℃ and the wet bulb temperature to 34-35℃ at a heating rate of 1℃ / 2h. The temperature is maintained for 35-45 hours, and the tobacco leaves turn 60-70% yellow and more than half of the leaves soften.

[0018] The aforementioned method for harvesting and curing upper tobacco leaves in autumn involves using a low-temperature, low-humidity, slow-yellowing curing technique in step S7 during the later stages of yellowing. This reduces both the dry-bulb and wet-bulb temperatures, prolongs the yellowing time of the tobacco leaves at 38℃, and promotes full softening, wilting, and yellowing of the leaves. The specific operation is as follows:

[0019] The dry bulb temperature is increased to 38℃ at a rate of 1℃ / 3h, and the wet bulb temperature is 34-36℃. The leaves are then baked at a stable temperature for 30-40h until 90% of the tobacco leaves turn yellow and wither and soften. After that, the dry bulb temperature is increased to 40℃ at a rate of 1℃ / 3h, and the wet bulb temperature is 34-35℃. The leaves are then baked at a stable temperature for 8-10h until the tobacco leaves turn yellow with green veins, fully soften, wither, and turn yellow, thus preventing the tobacco leaves from turning green again during baking.

[0020] The aforementioned method for harvesting and curing upper tobacco leaves in autumn involves using a low-temperature, low-humidity, slow-heating curing technique during step S7 to reduce the dry-bulb temperature, wet-bulb temperature, and heating rate, thereby promoting the fixation of the yellow color in the tobacco leaves. The specific operation is as follows:

[0021] At a heating rate of 1℃ / 3h, the dry bulb temperature is increased to 42℃, and the wet bulb temperature is 34-35℃. The temperature is maintained for 10-15h, resulting in curled tips and edges of the tobacco leaves, with a moisture loss of over 45%. Then, at a heating rate of 1℃ / 3h, the dry bulb temperature is increased to 44℃, and the wet bulb temperature is 34-35℃. The temperature is maintained for 10-15h, resulting in the main veins of the tobacco leaves in the high-temperature layer turning mostly yellow, and the leaves drying by 1 / 2 to 2 / 3. Finally, at a heating rate of 1℃ / 2h, the dry bulb temperature is increased to 48℃, and the wet bulb temperature is 35-36℃. The temperature is maintained for 10-15h, resulting in the main veins of the entire batch of tobacco leaves turning completely yellow and the leaves being completely dry.

[0022] The aforementioned method for harvesting and curing upper tobacco leaves in autumn involves using a low-temperature, low-humidity curing technique during the drying period in step S7. This reduces both the dry-bulb and wet-bulb temperatures, promoting the drying of the tobacco fibers. The specific operation is as follows:

[0023] With the temperature rising speed of 1℃ / h, the dry ball temperature is raised to 53-54℃, the wet ball temperature is 35-36℃, and the stable temperature baking is 3-5h, and the tobacco stem is dried by 1 / 3-1 / 2; then, with the temperature rising speed of 1℃ / h, the dry ball temperature is raised to 60-65℃, the wet ball temperature is 37-38℃, and the stable temperature baking is 15-25h, until the whole tobacco leaves are dried.

[0024] The foregoing tobacco leaf baking method after autumn upper part is, in steps S6 and S7, the circulating fan speed is according to the conventional operation.

[0025] Compared with the prior art, the method has the following advantages:

[0026] The method can promote the maturation and aging of the tobacco leaves, improve the maturation consistency of the tobacco leaves, and improve the softness of the baked tobacco leaves.

[0027] 1. The method is beneficial to the nutrition balance of the tobacco leaves, improves the maturation consistency, quality and baking characteristics of the fresh tobacco leaves;

[0028] 2. The method is beneficial to the degradation and transformation of the internal substances of the tobacco leaves, and improves the internal quality of the baked tobacco leaves;

[0029] 3. The method is beneficial to the appearance quality of the baked tobacco leaves, and reduces the proportion of the ashed tobacco and green tobacco;

[0030] 4. The method is beneficial to the reduction of the proportion of the rigid tobacco leaves, and improves the softness of the baked tobacco leaves.

[0031] Other advantages, objects and features of the present application will be in part apparent and in part pointed out hereinafter.

[0032] The accompanying drawings

[0033] Fig. 1 For the first group of tobacco plants treated by steps S1 and S2 of the present application and control pictures;

[0034] Fig. 2 For the second group of tobacco plants treated by steps S1 and S2 of the present application and control pictures;

[0035] Fig. 3 For the single plant of tobacco plants treated by steps S1 and S2 of the present application and control pictures. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be apparently and completely described below in combination with the tables in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without any creative work fall within the protection scope of the present application.

[0037] Embodiment 1. A method for curing upper tobacco leaves after autumn, comprising pre-harvesting treatment, harvesting and pre-curing treatment, and curing treatment.

[0038] The pre-harvesting treatment comprises:

[0039] S1, stem breaking: the stem breaking time is 1 day after the middle tobacco leaves are harvested, the stem breaking treatment is performed under good weather conditions, there is no dew or rain on the surface of the tobacco plant stem, the tobacco plant is prevented from being infected by diseases, the stem of the tobacco plant is broken at 10 cm below 4-6 upper tobacco leaves, the broken surface of the stem of the tobacco plant is 1 / 3 of the cross section of the stem, so as to promote the maturation and aging of the upper tobacco leaves; the broken stem can be cut by a pruning scissors to form a notch on the stem of the tobacco plant, the cross section of the notch is not more than 1 / 2 of the stem of the tobacco plant, and the stem is prevented from being broken.

[0040] S2, after the stem breaking treatment for 1 day, a leaf surface maturation nutrient solution is sprayed in the afternoon at 4-5 o'clock under good weather conditions, the leaf surface maturation nutrient solution used is a 40% ethylene solution diluted by 300 times of water and a potassium dihydrogen phosphate solution diluted by 200 times of water, the two diluted solutions are mixed according to a ratio of 1:1 to spray the leaf surface, and the spraying amount is 15-20 kg per mu, so as to further coordinate the nutrition balance of the upper tobacco leaves, improve the quality of the tobacco leaves, and promote the maturation and aging of the tobacco leaves.

[0041] The harvesting and pre-curing treatment steps comprise:

[0042] S3, fresh tobacco leaf maturation harvesting: more than 90% of the harvested fresh tobacco leaves are physiologically mature and technologically mature tobacco leaves, the leaves are mainly green and yellow, the leaf tips are yellow and withered, the leaf edges are yellow, most of the hairs are shed, and the main veins are basically white.

[0043] S4, Fresh tobacco leaf classification and tobacco leaf bundle: According to the maturity, the fresh tobacco leaf is roughly divided into three categories of under-ripe, mature and fully-ripe tobacco leaves, and is classified and bundled, and each bundle is bundled with 120 leaves; the under-ripe tobacco leaves are the leaves which are still ripe and the leaves with maturity lower than the still ripe leaves, the mature tobacco leaves are the physiologically mature and technologically mature tobacco leaves, and the fully-ripe tobacco leaves are the fresh tobacco leaves with higher maturity than the technologically mature leaves and with baking value;

[0044] S5, Fresh tobacco leaf loading: classified and layered, the same layer is loaded with the same quality, the under-ripe tobacco leaves are loaded in the low-temperature layer, the fully-ripe tobacco leaves are loaded in the high-temperature layer, and the mature tobacco leaves are loaded in the other layers, and the loading density is increased by 5% compared with the conventional loading density;

[0045] S6, Fresh tobacco leaf softening, wilting and yellowing: after the fresh tobacco leaves are loaded into the curing room, the cold air inlet and the moisture removal window are closed, the circulating fan is started for 2 hours, then the circulating fan is turned off for 15-25 hours to keep the temperature and humidity, until the fresh tobacco leaves are slightly softened, wilted and yellowed by 1-2 / 3.

[0046] The curing process includes the following steps:

[0047] S7, Curing: compared with the national standard GB / T 23219-2008, Tobacco Curing Technical Regulations, the circulating fan speed can be operated according to the standard, and the change is that the low-temperature and moisture-retention slow yellowing technology is used in the early stage of yellowing, the dry ball temperature and the temperature rising rate are reduced, the moisture removal rate and the tobacco leaf drying rate are reduced, the low-temperature yellowing time before 38℃ is prolonged, and the tobacco leaves are fully softened, wilted and yellowed, and the specific operation is as follows: after ignition, the dry ball temperature is increased to 32℃ at a temperature rising rate of 1℃ / h, the wet ball temperature is 32℃, the temperature is stabilized for 15 hours, and the tobacco leaves are yellowed by 1 / 3; then the dry ball temperature is increased to 35℃ at a temperature rising rate of 1℃ / 2h, the wet ball temperature is 34℃, the temperature is stabilized for 35 hours, the tobacco leaves are yellowed by 6 / 3, and the leaf blades are softened by more than 1 / 2.

[0048] The low-temperature and low-humidity slow yellowing technology is used in the late stage of yellowing, the dry ball temperature and the wet ball temperature are reduced, the tobacco leaf yellowing time at 38℃ is prolonged, and the tobacco leaves are fully softened, wilted and yellowed, and the specific operation is as follows: the dry ball temperature is increased to 38℃ at a temperature rising rate of 1℃ / 3h, the wet ball temperature is 34℃, the temperature is stabilized for 15 hours, then the wet ball temperature is increased to 35℃, the temperature is stabilized for 20 hours until the tobacco leaves are yellowed by 9 / 3 and softened; then the dry ball temperature is increased to 40℃ at a temperature rising rate of 1℃ / 3h, the wet ball temperature is 35℃, the temperature is stabilized for 8 hours, the tobacco leaves are yellowed and the veins are fully softened, and the tobacco leaves are prevented from being yellowed and green.

[0049] The color fixing period adopts low-temperature, low-humidity and slow-rising temperature color fixing baking technology, reduces the dry ball temperature, the wet ball temperature and the rising rate, promotes the yellow fixation of the tobacco leaves, and the specific operation is as follows: the dry ball temperature is raised to 42℃ at the rising rate of 1℃ / 3h, the wet ball temperature is 34℃, and the tobacco leaves are baked for 10h at the stable temperature, the tobacco leaves are hooked and the edge is curled, and the water loss is more than 45%; then, the dry ball temperature is raised to 44℃ at the rising rate of 1℃ / 3h, the wet ball temperature is 35℃, and the tobacco leaves are baked for 10h at the stable temperature, the main veins of the tobacco leaves in the high-temperature layer are basically yellow, and the tobacco leaf blades are dried by 1 / 2-2 / 3; then, the dry ball temperature is raised to 48℃ at the rising rate of 1℃ / 2h, the wet ball temperature is 35℃, and the tobacco leaves are baked for 10h at the stable temperature, the main veins of the whole tobacco leaves are yellow, and the tobacco leaf blades are dried.

[0050] The dry vein period adopts low-temperature, low-humidity and dry vein baking technology, reduces the dry ball temperature and the wet ball temperature in the dry vein period, and promotes the dryness of the tobacco veins, and the specific operation is as follows: the dry ball temperature is raised to 53℃ at the rising rate of 1℃ / h, the wet ball temperature is 36℃, and the tobacco leaves are baked for 3h at the stable temperature, the tobacco veins are dried by 1 / 3-1 / 2; then, the dry ball temperature is raised to 65℃ at the rising rate of 1℃ / h, the wet ball temperature is 37℃, and the tobacco leaves are baked for 15h at the stable temperature, until the whole tobacco leaves are dried.

[0051] Example 2. The tobacco leaf picking and baking method after autumn, which comprises picking pre-treatment, picking and pre-baking treatment and baking treatment.

[0052] The picking pre-treatment comprises:

[0053] S1, stem breaking: the stem breaking time is 1-2 days after the middle tobacco leaf picking, the stem breaking treatment is performed in the relatively good weather, there is no dew drop or rain on the surface of the tobacco stem, the tobacco plant is prevented from being infected by diseases, the tobacco stem is broken at 15cm below 4-6 upper tobacco leaves, the broken surface of the tobacco stem is 5 / 12 of the cross section of the stem, so as to promote the maturity and aging of the upper tobacco leaves; the stem breaking can be performed by using a pruning scissors to cut a notch on the tobacco stem, the cross section of the notch is not more than 1 / 2 of the tobacco stem, and the tobacco stem is not broken.

[0054] S2, after 1-2 days of the stem breaking treatment, a leaf surface maturity promoting nutrient solution is sprayed at 9-10am in the good weather, the leaf surface maturity promoting nutrient solution used is a 40% ethylene solution diluted by 400 times of water and a potassium dihydrogen phosphate solution diluted by 250 times of water, the two diluted solutions are mixed according to the proportion of 1:1 for leaf surface spraying, the spraying amount per mu is 15-20kg, the nutrition balance of the upper tobacco leaves is further coordinated, the quality of the tobacco leaves is improved, and the maturity and aging of the tobacco leaves are promoted.

[0055] The picking and pre-baking treatment steps comprise:

[0056] S3, Fresh tobacco leaf mature harvest: more than 90% of the harvested fresh tobacco leaf is physiologically mature and technologically mature tobacco leaf, the leaf blade is mainly greenish yellow and light yellow, the leaf tip is yellow and withered, the leaf edge is yellow, most of the villi have fallen off, and the main vein is basically white, and most of the branch vein is white;

[0057] S4, Fresh tobacco leaf classification and sorting: the fresh tobacco leaf is roughly divided into three categories of under-mature, mature and fully mature tobacco leaf according to maturity, and is classified and sorted, and 125 leaves are sorted per pole; the under-mature tobacco leaf is the tobacco leaf with a maturity degree lower than that of the mature tobacco leaf; the mature tobacco leaf is the physiologically mature and technologically mature tobacco leaf; and the fully mature tobacco leaf is the fresh tobacco leaf with a maturity degree higher than that of the technologically mature tobacco leaf and with baking value;

[0058] S5, Fresh tobacco leaf loading: classification, same layer and same quality loading, under-mature tobacco leaf is loaded in a low-temperature layer, fully mature tobacco leaf is loaded in a high-temperature layer, and other layers are loaded with mature tobacco leaf, and the loading density is increased by 10% compared with the conventional one;

[0059] S6, Fresh tobacco leaf softening, wilting and yellowing: after the fresh tobacco leaf is loaded into the curing room, the cold air inlet and the moisture removal window are closed, the circulating fan is started for 2.5 h, then the circulating fan is turned off for 20 h to keep warm and humid, until the fresh tobacco leaf is slightly softened, wilted and yellowed by 1-2.

[0060] The curing treatment steps include:

[0061] S7, Curing: compared with the national standard GB / T 23219-2008, Curing Technology Regulation of Tobacco, the circulating fan speed size can be operated according to the standard, which is changed to low-temperature and humid slow yellowing curing technology in the early stage of yellowing, the dry ball temperature and the temperature rising rate are reduced, the moisture removal rate and the tobacco leaf drying rate are reduced, the low-temperature yellowing time before 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed, and the specific operation is as follows: after ignition, the dry ball temperature is increased to 32℃ at a temperature rising rate of 1℃ / h, the wet ball temperature is 32℃, the temperature is kept constant for 18 h, and the tobacco leaf is yellowed by 3-5; then the dry ball temperature is increased to 35℃ at a temperature rising rate of 1℃ / 2h, the wet ball temperature is 34℃, the temperature is kept constant for 40 h, the tobacco leaf is yellowed by 6-7, and the leaf blade is softened by more than 1 / 2.

[0062] In the late stage of yellowing, low-temperature and low-humidity slow yellowing curing technology is adopted, the dry ball temperature and the wet ball temperature are reduced, the tobacco leaf yellowing time at 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed, and the specific operation is as follows: the dry ball temperature is increased to 38℃ at a temperature rising rate of 1℃ / 3h, the wet ball temperature is 35℃, the temperature is kept constant for 38 h, the tobacco leaf is yellowed by 9, and the tobacco leaf is wilted and softened; then the dry ball temperature is increased to 40℃ at a temperature rising rate of 1℃ / 3h, the wet ball temperature is 35℃, the temperature is kept constant for 9 h, the tobacco leaf is yellow and green, and the tobacco leaf is fully softened, wilted and yellowed, and the tobacco leaf is prevented from being yellowed.

[0063] The color fixing period adopts low-temperature, low-humidity and slow-rising temperature color fixing baking technology, reduces the dry ball temperature, the wet ball temperature and the rising rate, promotes the yellow fixation of the tobacco leaves, and the specific operation is as follows: the dry ball temperature is raised to 42℃ at the rising rate of 1℃ / 3h, the wet ball temperature is 34℃, and the tobacco leaves are baked for 13h at the stable temperature, the tobacco leaves are hooked and the edge is curled, and the water loss is more than 45%; then, the dry ball temperature is raised to 44℃ at the rising rate of 1℃ / 3h, the wet ball temperature is 35℃, and the tobacco leaves are baked for 13h at the stable temperature, the main veins of the tobacco leaves in the high-temperature layer are basically yellow, and the tobacco leaf blades are dried by 1 / 2-2 / 3; then, the dry ball temperature is raised to 48℃ at the rising rate of 1℃ / 2h, the wet ball temperature is 35-36℃, and the tobacco leaves are baked for 13h at the stable temperature, the main veins of the whole tobacco leaves are yellow, and the tobacco leaf blades are dried.

[0064] The dry vein period adopts low-temperature, low-humidity and dry vein baking technology, reduces the dry ball temperature and the wet ball temperature in the dry vein period, and promotes the dryness of the tobacco vein, and the specific operation is as follows: the dry ball temperature is raised to 53-54℃ at the rising rate of 1℃ / h, the wet ball temperature is 35-36℃, and the tobacco leaves are baked for 4h at the stable temperature, the tobacco vein is dried by 1 / 3-1 / 2; then, the dry ball temperature is raised to 63℃ at the rising rate of 1℃ / h, the wet ball temperature is 37-38℃, and the tobacco leaves are baked for 20h at the stable temperature, until the whole tobacco leaves are dried.

[0065] Example 3. An upper tobacco leaf harvesting and baking method after autumn, which comprises pre-harvesting treatment, harvesting and pre-baking treatment, and baking treatment.

[0066] The pre-harvesting treatment comprises:

[0067] S1, the stem breaking time is 1-2 days after the middle tobacco leaf harvesting, the stem breaking treatment is performed in the relatively good weather, there is no dew drop or rain on the surface of the tobacco stem, the tobacco plant is prevented from being infected by diseases, the stem of the tobacco plant is broken at 20cm below 4-6 upper tobacco leaves, the broken surface of the stem breaking treatment is 1 / 3-1 / 2 of the cross section of the stem, so as to promote the maturation and aging of the upper tobacco leaves; the stem breaking can be performed by using a pruning scissors to cut a notch on the tobacco stem, the cross section of the notch cannot exceed 1 / 2 of the tobacco stem, so as to avoid breaking;

[0068] S2, after the stem breaking treatment for 1-2 days, the leaf surface maturation nutrient solution is sprayed in the morning at 9-10 o'clock in the good weather, the leaf surface maturation nutrient solution used is a 40% ethylene solution diluted by 500 times of water and a potassium dihydrogen phosphate solution diluted by 300 times of water, the two diluted solutions are mixed according to the proportion of 1:1 to spray the tobacco leaves, and the spraying amount is 15-20kg per mu, so as to further coordinate the nutrition balance of the upper tobacco leaves, improve the quality of the tobacco leaves, and promote the maturation and aging of the tobacco leaves;

[0069] The harvesting and pre-baking treatment comprises:

[0070] S3, Fresh tobacco leaf mature harvest: more than 90% of the harvested fresh tobacco leaf is physiologically mature and technologically mature tobacco leaf, the leaf blade is mainly green and yellow, the leaf tip is yellow and withered, the leaf edge is yellow, most of the villi have fallen off, and the main vein is basically white, and most of the branch vein is white;

[0071] S4, Fresh tobacco leaf classification and sorting: the fresh tobacco leaf is roughly divided into three categories of under-mature, mature and fully mature tobacco leaf according to the maturity, and is classified and sorted, and 130 pieces of tobacco are sorted per pole; the under-mature tobacco leaf is the tobacco leaf with a maturity lower than that of the mature tobacco leaf; the mature tobacco leaf is the physiologically mature and technologically mature tobacco leaf; and the fully mature tobacco leaf is the fresh tobacco leaf with a maturity higher than that of the technologically mature tobacco leaf and with a baking value;

[0072] S5, Fresh tobacco leaf loading: the classified and layered fresh tobacco leaf is loaded, the under-mature tobacco leaf is loaded in the low-temperature layer, the fully mature tobacco leaf is loaded in the high-temperature layer, and the mature tobacco leaf is loaded in the other layers, and the loading density is increased by 15% than that of the conventional loading;

[0073] S6, Fresh tobacco leaf softening, wilting and yellowing: after the fresh tobacco leaf is loaded into the curing room, the cold air inlet and the moisture removal window are closed, the circulating fan is started for 3 h, then the circulating fan is turned off for 25 h to keep the temperature and humidity, until the fresh tobacco leaf is slightly softened, wilted and yellowed by 1-2.

[0074] The curing treatment steps include:

[0075] S7, Curing: compared with the national standard GB / T 23219-2008, Curing Technology Regulation for Tobacco, the circulating fan speed can be operated according to the standard, which is changed to low-temperature and high-humidity slow yellowing curing technology in the early stage of yellowing, the dry ball temperature and the temperature rising rate are reduced, the moisture removal rate and the tobacco leaf drying rate are reduced, the low-temperature yellowing time before 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed, and the specific operation is as follows: after ignition, the dry ball temperature is increased to 32℃ at a temperature rising rate of 1℃ / h, the wet ball temperature is 31℃, the temperature is kept stable for 20 h, and the tobacco leaf is yellowed by 4; then the dry ball temperature is increased to 36℃ at a temperature rising rate of 1℃ / 2h, the wet ball temperature is 35℃, the temperature is kept stable for 45 h, the tobacco leaf is yellowed by 7, and the leaf blade is softened by more than 1 / 2.

[0076] In the late stage of yellowing, low-temperature and low-humidity slow yellowing curing technology is adopted, the dry ball temperature and the wet ball temperature are reduced, the tobacco leaf yellowing time at 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed, and the specific operation is as follows: the dry ball temperature is increased to 38℃ at a temperature rising rate of 1℃ / 3h, the wet ball temperature is 36℃, the temperature is kept stable for 40 h, the tobacco leaf is yellowed by 9, and the tobacco leaf is wilted and softened; then the dry ball temperature is increased to 40℃ at a temperature rising rate of 1℃ / 3h, the wet ball temperature is 35℃, the temperature is kept stable for 10 h, the tobacco leaf is yellow and green, and the tobacco leaf is fully softened, wilted and yellowed, and the tobacco leaf is prevented from being yellowed.

[0077] The color fixing period adopts low-temperature, low-humidity and slow-temperature-rising color fixing baking technology, the dry ball temperature, the wet ball temperature and the temperature rising rate are reduced, the yellow color of the tobacco leaf is fixed, and the specific operation is as follows: the dry ball temperature is raised to 42 DEG C at the temperature rising speed of 1 DEG C / 3h, the wet ball temperature is 35 DEG C, the temperature is stably baked for 15h, the tobacco leaf is hooked and rolled, and the water loss is more than 45%; then, the dry ball temperature is raised to 44 DEG C at the temperature rising speed of 1 DEG C / 3h, the wet ball temperature is 34 DEG C, the temperature is stably baked for 15h, the main vein of the high-temperature layer tobacco leaf is basically yellow, and the tobacco leaf blade is dried by 1 / 2-2 / 3; then, the dry ball temperature is raised to 48 DEG C at the temperature rising speed of 1 DEG C / 2h, the wet ball temperature is 36 DEG C, and the temperature is stably baked for 15h, the main vein of the whole tobacco leaf is yellow, and the leaf blade is dry.

[0078] The dry muscle period adopts low-temperature, low-humidity and dry muscle baking technology, the dry muscle period dry ball temperature and wet ball temperature are reduced, and the tobacco muscle is dried, and the specific operation is as follows: the dry ball temperature is raised to 53 DEG C at the temperature rising speed of 1 DEG C / h, the wet ball temperature is 36 DEG C, the temperature is stably baked for 5h, and the tobacco muscle is dried by 1 / 2; then, the dry ball temperature is raised to 65 DEG C at the temperature rising speed of 1 DEG C / h, the wet ball temperature is 37 DEG C, and the temperature is stably baked for 25h, until the whole tobacco leaf is dry.

[0079] Meanwhile, the method is used for the upper tobacco leaf harvesting method of Yunchen 87 tobacco leaf, the test is carried out in Weining County of Guizhou Province in 2021-2022, the tested tobacco variety is Yunchen 87, and the upper tobacco leaf is used as the test material.

[0080] As shown in Figs. 1-3 The contrast picture after the actual operation of the applicant in the tobacco field using the picking pre-treatment step, it can be seen from the figure that the tobacco leaf after using the picking pre-treatment is more consistent in yellow consistency and yellow degree, the time is earlier, and the influence of the later rainy season on the tobacco leaf harvesting can be greatly reduced. At the same time, through the statistics of the data of tobacco leaves in many regions, table 1 data is obtained.

[0081] Table 1 Influence of leaf surface spraying of maturity promoting nutrient solution and stem breaking on maturity and baking characteristics of upper fresh tobacco leaf

[0082]

[0083] Note: Different lowercase letters represent significant differences between different treatments at the 5% level. The same below

[0084] Tables 2-6 are analysis data of the upper tobacco leaf obtained by the upper tobacco leaf harvesting method after autumn

[0085] Table 2 Influence of different treatments on appearance quality of the upper tobacco leaf after baking

[0086]

[0087] Table 3 Influence of different treatments on chemical component content of the tobacco leaf after baking

[0088]

[0089] Table 4 Effects of different treatments on sensory quality of cured tobacco leaves

[0090]

[0091] Note: Sensory quality evaluation is the total score of aroma quality, aroma amount, eating taste, odor, irritation and strength, each being 10 points.

[0092] Table 5 Effects of different treatments on grade structure of cured tobacco leaves (%)

[0093]

[0094]

[0095] Table 6 Effects of different treatments on softness of cured tobacco leaves

[0096]

[0097] The test data in the above table can prove that the upper tobacco leaves harvesting method after autumn can: 1. be conducive to the nutrition balance of upper tobacco leaves after autumn, improve the consistency of fresh tobacco leaf maturity, quality and curing characteristics; 2. be conducive to the sufficient degradation and transformation of internal substances of tobacco leaves, improve the internal quality of cured tobacco leaves; 3. be conducive to improving the appearance quality of cured tobacco leaves, reducing the proportion of hanging ash and green smoke; 4. be conducive to reducing the proportion of rigid tobacco leaves, improving the softness of cured tobacco leaves. It has good practical value and generalizability.

Claims

1. A method of curing upper leaves after the first curing, characterized by, Comprise: S1, stem breaking: 1-2 days after postharvest of middle tobacco leaves, breaking the stem of tobacco plant at 10-20 cm below 4-6 upper tobacco leaves, the cross section of the breaking stem of tobacco plant is 1 / 3-1 / 2 of the cross section of the stem, to promote maturation and aging of the upper tobacco leaves; S2, spraying leaf maturation nutrient solution: using 300-500 times water to dilute 40% ethephon solution, 200-300 times water to dilute potassium dihydrogen phosphate solution, mixing the two diluted solutions in a ratio of 1:1 for foliar spraying, spraying amount is 15-20 kg per mu, to further coordinate the nutrient balance of the upper tobacco leaves, improve the quality of tobacco leaves, and promote maturation and aging of tobacco leaves; S3, fresh tobacco leaf harvesting: more than 90% of the harvested fresh tobacco leaves are physiologically mature and technologically mature, the leaves are mainly green and yellow, the leaf tips are yellow and withered, the leaf edges are yellow, most of the hairs have fallen off, and the main veins are basically white, and the branch veins are mostly white; S4, fresh tobacco leaf classification and baling: according to the maturity, the fresh tobacco leaves are roughly divided into three categories of under-mature, mature and over-mature leaves, and are classified and baled, 120-130 leaves per bale; S5, fresh tobacco leaf loading: classified and layered, same layer and same quality loading, under-mature leaves are loaded in the low temperature layer, over-mature leaves are loaded in the high temperature layer, and other layers are loaded with mature leaves, the loading density is increased by 5-15% compared with the conventional method; S6, fresh tobacco leaf softening, wilting and yellowing: after loading the fresh tobacco leaves into the curing room, close the cold air inlet and the moisture removal window, start the circulating fan for 2-3 h, then turn off the circulating fan for 15-25 h, until the fresh tobacco leaves are slightly soft and wilted, and the tobacco leaves are yellowed by 1-2; S7, curing: using low temperature and high humidity slow yellowing curing technology in the early stage of yellowing, low temperature and low humidity slow yellowing curing technology in the late stage of yellowing to promote the full softening, wilting and yellowing of tobacco leaves, low temperature and low humidity slow warming curing technology in the color fixing period to promote the yellow color fixation of tobacco leaves, and low temperature and low humidity dry stem curing technology in the dry stem period to promote the drying of tobacco stems. In step S7, the low-temperature and moisture slow yellowing baking technology is adopted in the early stage of yellowing, the dry ball temperature and the heating rate are reduced, the moisture removal rate and the tobacco leaf drying rate are slowed down, the low-temperature yellowing time before 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed. The specific operation is as follows: after ignition, the dry ball temperature is increased to 32℃ at a heating rate of 1℃ / h, the wet ball temperature is 31~32℃, the temperature is stabilized for 15~20h, and the tobacco leaf is yellowed by 3~5%; then the dry ball temperature is increased to 35~36℃ at a heating rate of 1℃ / 2h, the wet ball temperature is 34~35℃, the temperature is stabilized for 35~45h, the tobacco leaf is yellowed by 6~7%, and the leaf is softened by more than 1 / 2; in step S7, the low-temperature and low-moisture slow yellowing baking technology is adopted in the late stage of yellowing, the dry ball temperature and the wet ball temperature are reduced, the tobacco leaf yellowing time at 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed. The specific operation is as follows: the dry ball temperature is increased to 38℃ at a heating rate of 1℃ / 3h, the wet ball temperature is 34~36℃, the temperature is stabilized for 30~40h, the tobacco leaf is yellowed by 9% and wilted and softened; then the dry ball temperature is increased to 40℃ at a heating rate of 1℃ / 3h, the wet ball temperature is 34~35℃, the temperature is stabilized for 8~10h, the tobacco leaf is yellow and green, fully softened, wilted and yellowed, and the tobacco leaf is prevented from being yellowed again during baking; in step S7, the low-temperature and low-moisture slow yellowing baking technology is adopted in the late stage of yellowing, the dry ball temperature and the wet ball temperature are reduced, the tobacco leaf yellowing time at 38℃ is prolonged, and the tobacco leaf is fully softened, wilted and yellowed. The specific operation is as follows: the dry ball temperature is increased to 42℃ at a heating rate of 1℃ / 3h, the wet ball temperature is 34~35℃, the temperature is stabilized for 10~15h, the tobacco leaf is hooked and curled, and the water loss is more than 45%; then the dry ball temperature is increased to 44℃ at a heating rate of 1℃ / 3h, the wet ball temperature is 34~35℃, the temperature is stabilized for 10~15h, the main veins of the tobacco leaf in the high-temperature layer are basically yellow, and the tobacco leaf is dried by 1 / 2~2 / 3; then the dry ball temperature is increased to 48℃ at a heating rate of 1℃ / 2h, the wet ball temperature is 35~36℃, the temperature is stabilized for 10~15h, the main veins of the tobacco leaf in the whole kiln are yellow, and the leaf is fully dried.

2. The upper cut tobacco harvesting method according to claim 1, characterized in that, In step S1, the relative better weather is selected for stem breaking treatment, and there is no dew or rain on the surface of the tobacco plant stem to prevent the tobacco plant from being infected with diseases.

3. The upper cut tobacco harvesting method according to claim 2, characterized by, In step S2, after 1~2 days of stem breaking treatment, the better weather is selected to spray the leaf maturation nutrient solution at 9~10am or 4~5pm.

4. The upper cut tobacco leaf harvesting method according to claim 3, characterized by, In step S4, the under-ripe tobacco leaf is the tobacco leaf with maturity lower than that of the semi-ripe tobacco leaf, the mature tobacco leaf is the tobacco leaf with physiological maturity and process maturity, and the fully ripe tobacco leaf is the fresh tobacco leaf with higher maturity than the process maturity and baking value.

5. The upper cut tobacco harvesting method according to claim 4, wherein In step S7, low-temperature and low-humidity drying is adopted in the drying stage to reduce the dry-bulb temperature and wet-bulb temperature, so as to promote the drying of tobacco stems. The specific operation is as follows: the dry-bulb temperature is increased to 53-54℃ at a temperature increasing rate of 1℃ / h, the wet-bulb temperature is 35-36℃, and the tobacco stems are dried by 1 / 3-1 / 2 after stable temperature drying for 3-5h; then, the dry-bulb temperature is increased to 60-65℃ at a temperature increasing rate of 1℃ / h, the wet-bulb temperature is 37-38℃, and the tobacco stems are dried to be completely dry after stable temperature drying for 15-25h.

6. The upper cut tobacco leaf harvesting method according to claim 5, wherein In steps S6 and S7, the rotating speed of the circulating fan can be determined according to conventional operation.

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