Full-growth-period rainy and low-sunshine tobacco leaf picking and baking method

Abstract

The invention discloses a full-growth-period multi-rain and low-sunshine tobacco leaf picking and baking method which comprises the steps of fresh tobacco leaf suitable-ripening harvesting, fresh tobacco leaf classification and reasonable tobacco weaving, fresh tobacco leaf reasonable loading into a kang, tobacco leaf surface excess moisture reduction and baking, a one-fast and two-slow baking technology is adopted in the early stage of yellowing of baking, and a three-slow baking technology is adopted in the middle and later stage of yellowing; a two-low and one-slow baking technology is adopted in the color fixing period; a one-low and one-slow baking technology is adopted in the stem drying stage; tests prove that the picking and baking method has the advantages that the appearance quality of the baked tobacco leaves, especially the tobacco leaf oil content and the softness index, can be improved; internal material loss of the tobacco leaves is reduced, and the single leaf weight of the cured tobacco leaves is increased; the grade structure of flue-cured tobacco leaves can be improved, and the proportion of green vinasse tobacco and ash tobacco is reduced.

Description

Technical Field

[0001] The invention relates to a method for harvesting and curing tobacco leaves with high rainfall and low sunshine in the whole growth period, belonging to the technical field of tobacco leaf curing. Background Art

[0002] Since the transplanting of flue-cured tobacco in April this year, most tobacco-growing areas in the south of the country have entered the rainy season, with more rain and less sunshine until the baking season, when the rainfall has slightly decreased. The special climatic conditions of this year have led to a lack of internal nutrients in fresh tobacco leaves, high content of chlorophyll and protein, rapid water loss, slow yellowing, and poor baking characteristics, which have brought great difficulty to tobacco leaf baking; from the perspective of the quality of the tobacco leaves after baking, the overall deviation in the early stage of baking is compared with previous years, such as thin tobacco leaves, light weight of single leaves, high ash and green residue rates, and insufficient oil. Based on this situation, baking technicians carried out multiple tests and verifications in multiple production areas across the province, and finally formed a method for harvesting and baking tobacco leaves with more rain and less sunshine throughout the growth period, which can significantly improve the quality of the tobacco leaves after baking. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine, which can improve the single leaf weight and appearance quality of the tobacco leaves after curing, and can overcome the shortcomings of the prior art.

[0004] The technical solution of the present invention is:

[0005] The method of harvesting and curing tobacco leaves during the whole growth period with high rainfall and low sunshine includes:

[0006] S1, Harvesting of fresh tobacco leaves at the right maturity: Most of the harvested fresh tobacco leaves are physiologically mature and technologically mature, with the yellowing degree of the leaves being 10% to 20% lower than normal, the hairs falling off, and the main veins and branch veins being shiny;

[0007] S2, classification and reasonable arrangement of fresh tobacco leaves: fresh tobacco leaves are roughly divided into four categories according to their maturity characteristics: unripe, physiologically mature, technologically mature and overripe. Unripe and overripe tobacco leaves with no baking value are removed and classified into rods. The amount of tobacco per rod is reduced by 10% to 15% compared with the conventional method.

[0008] S3, fresh tobacco leaves are properly loaded on the kang: physiologically mature tobacco leaves are loaded on the low-temperature layer, and technologically mature tobacco leaves are loaded on the high-temperature layer. Each standard intensive curing room is loaded with 300 to 350 tobacco rods;

[0009] S4, reduce excess moisture on the surface of tobacco leaves: After the tobacco is loaded in the flue-curing room, open the air inlet and run the circulating fan at high speed for 2 to 3 hours to reduce excess moisture on the surface of tobacco leaves in the flue-curing room;

[0010] S5, baking: the one fast and two slow baking technology is adopted in the early stage of yellowing, and the three slow baking technology is adopted in the middle and late stages of yellowing; the two lows and one slow baking technology is adopted in the color fixing stage; the one low and one slow baking technology is adopted in the dry tendon stage; the one fast and two slow baking technology adopted in the early stage of yellowing refers to the fast heating, slow dehumidification, and slow yellowing baking technology adopted in the early stage of yellowing to reduce the loss of internal substances and water loss of tobacco leaves, increase the yellowing temperature of tobacco leaves, and promote the full preheating of tobacco leaves; the three slow baking technology is adopted in the middle and late stages of yellowing, which refers to the slow heating, slow dehumidification, and slow yellowing adopted in the middle and late stages of yellowing to promote the full softening, withering and yellowing of tobacco leaves; the two lows and one slow baking technology is adopted in the color fixing stage, which refers to the low temperature, low humidity, slow heating and color fixing baking technology adopted in the color fixing stage to promote the yellow color of tobacco leaves to be fixed and reduce ash; the one low and one slow baking technology is adopted in the dry tendon stage, which refers to the low temperature, slow heating, dry tendon and fragrance preservation baking technology adopted in the dry tendon stage to promote the drying of tobacco tendons and improve the oil quality of tobacco leaves after baking.

[0011] The above-mentioned method for harvesting and curing tobacco leaves with high rainfall and low sunshine during the entire growth period is that the specific operation of the one fast and two slow baking technology adopted in the early stage of yellowing is as follows: after ignition, the dry-bulb temperature is raised to 33.0°C and the wet-bulb temperature is 32.5-33.0°C at a heating rate of 1°C / h, and the baking is carried out at a steady temperature for 1-2 hours; thereafter, the dry-bulb temperature is raised to 36.0°C and the wet-bulb temperature is 35.5-36.0°C at a heating rate of 1°C / h, and the baking is carried out at a steady temperature for 5-6 hours, until the tobacco leaves in the high-temperature layer turn 10% to 20% yellow.

[0012] The above-mentioned method for harvesting and curing tobacco leaves with high rainfall and low sunshine during the whole growth period is as follows: the specific operation of the three-slow baking technology in the middle and late stages of yellowing is as follows: the dry-bulb temperature is raised to 38.0-39.0°C at a rate of 1°C / 2-3h, the wet-bulb temperature is 37.0-38.0°C, and the temperature is kept constant for 10-20h until the high-temperature layer of tobacco leaves turns 50% to 60% yellow; the dry-bulb temperature is raised to 40.0-41.0°C at a rate of 1°C / 3-4h, The wet-bulb temperature is 36.5-37.5℃, and the tobacco leaves are baked at a steady temperature for 10-15h, until they turn 70% to 80% yellow. Then, lower the wet-bulb temperature to 35.5-36.5℃, and bake at a steady temperature for 4-5h. Then, keep the wet-bulb temperature constant, and increase the dry-bulb temperature to 42.0-43.0℃ at a heating rate of 1℃ / 3-5h, and bake at a steady temperature for 10-14h, until more than 98% of the tobacco leaves in the high-temperature layer turn yellow and turn blue, and become fully softened and withered.

[0013] The above-mentioned method for harvesting and curing tobacco leaves in the rainy and low-sunlight season during the whole growth period is as follows: the specific operation of the two-low and one-slow baking technology used in the color fixing period is as follows: the dry-bulb temperature is raised to 44.0-45.0°C at a heating rate of 1°C / 4-5h, the wet-bulb temperature is 35.0-36.0°C, and the temperature is kept constant for 6-10h until the tobacco leaves are completely yellow, some of the main tendons are white, and the leaves are more than 1 / 10 dry; then, the dry-bulb temperature is raised to 44.0-45.0°C at a heating rate of 1°C / 4-5h, and the wet-bulb temperature is 35.0-36.0°C. The temperature is raised to 47.0-49.0℃, the wet-bulb temperature is 36.0-37.5℃, and the temperature is kept constant for 8-12h until the main veins of the tobacco leaves in the high-temperature layer basically turn yellow and the tobacco leaves are more than 1 / 2 dry. Afterwards, the temperature is raised to 53.0-54.0℃, the wet-bulb temperature is 38.0-39.0℃ at a heating rate of 1℃ / 3-4h, and the temperature is kept constant for 10-12h until the tobacco leaves on the whole kang are completely dry and the main tendons are more than 1 / 3 dry.

[0014] The above-mentioned method for harvesting and curing tobacco leaves with high rainfall and low sunshine during the entire growth period is that the specific operation of the low-slow baking technology adopted in the dry-stem period is as follows: at a heating rate of 1°C / 2-3h, the dry-bulb temperature is raised to 60.0°C, the wet-bulb temperature is 39.0-40.0°C, and the tobacco leaves are baked at a steady temperature for 6-10h until more than 2 / 3 of the tobacco leaves are dried; thereafter, at a heating rate of 1°C / 1-2h, the dry-bulb temperature is raised to 65.0°C, the wet-bulb temperature is 40.0-41.0°C, and the tobacco leaves are baked at a steady temperature until the entire kang is completely dry.

[0015] The above-mentioned method for harvesting and curing tobacco leaves with high rainfall and low sunshine during the whole growth period is as follows: in step S1, cloudy and rainy weather is selected as much as possible for harvesting tobacco leaves.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The present invention can reduce the loss of internal substances in tobacco leaves through measures such as timely harvesting of fresh tobacco leaves, classification of fresh tobacco, reasonable packing of tobacco leaves and reduction of excess moisture on the surface of tobacco leaves, ensure smooth ventilation and moisture removal in the curing room, facilitate yellowing and timely coloring of tobacco leaves, thereby improving the single leaf weight and appearance quality of the cured tobacco leaves. In terms of baking technology, the one-fast-two-slow baking technology is used in the early stage of yellowing to reduce the loss of internal substances and water loss of tobacco leaves, increase the yellowing temperature of tobacco leaves, and promote sufficient preheating of tobacco leaves, providing conditions for the subsequent full yellowing of tobacco leaves, while increasing the weight of single tobacco leaves after baking; the three-slow baking technology is used in the middle and late stages of yellowing, which can promote the full softening, withering and yellowing of tobacco leaves, improve the softness and looseness of tobacco leaves after baking, and reduce the rate of green slag and ash-hanging tobacco leaves; the two-low-one-slow baking technology is used in the color-fixing period to promote the yellow color of tobacco leaves, improve the softness and looseness of tobacco leaves after baking, and reduce the rate of green slag and ash-hanging tobacco leaves; the one-low-one-slow baking technology is used in the dry tendon period, which means that the low-temperature and slow-heating dry tendon fragrance-preserving baking technology is used in the dry tendon period to promote the drying of tobacco tendons, reduce the loss of aroma substances in tobacco leaves, and increase the oil content of tobacco leaves after baking. In short, this method has the following benefits:

[0018] 1. It is beneficial to improve the appearance quality of tobacco leaves after curing, especially the oil content and softness index of tobacco leaves;

[0019] 2. It is beneficial to reduce the loss of internal substances in tobacco leaves and increase the weight of single leaf after curing;

[0020] 3. It is beneficial to improve the grade structure of tobacco leaves after curing and reduce the proportion of green tobacco and ash tobacco.

[0021] 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.

[0022] Instruction Manual

[0023] Figure 1 This is a picture of tobacco leaves baked by the baking method of the present invention;

[0024] Figure 2 This is a picture of tobacco leaves after being baked using the conventional baking method. DETAILED DESCRIPTION

[0025] 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.

[0026] Taking Suiyang, Guizhou as an example, after the flue-cured tobacco was transplanted in April 2024, it has been rainy and with little sunshine, resulting in a lack of internal nutrients in fresh tobacco leaves, high contents of chlorophyll and protein, rapid water loss, slow yellowing, and poor baking characteristics, which brings great difficulty to tobacco leaf baking; from the perspective of the quality of tobacco leaves after baking, the overall deviation in the early stage of baking is compared with previous years, such as thin tobacco leaves, light weight of single leaves, high ash and green residue rates, and insufficient oil. The "three-stage seven-step method" of the traditional tobacco leaf baking instruction manual cannot bake out tobacco leaves of better quality. After the technical personnel analyzed the quality of tobacco leaves, proposed a new baking plan and verified it many times, the following method for harvesting and baking tobacco leaves with high rainfall and little sunshine during the entire growth period is proposed

[0027] Example 1.

[0028] 1. A method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine, characterized by comprising:

[0029] S1. Harvesting of fresh tobacco leaves at the right maturity: Most of the harvested fresh tobacco leaves are physiologically mature and technologically mature. The yellowing degree of the leaves is 10% to 20% lower than normal. The hairs have fallen off, and the main veins and side veins are shiny. The picking time should be chosen on cloudy days with little rain.

[0030] S2, classification and reasonable arrangement of fresh tobacco leaves: fresh tobacco leaves are roughly divided into four categories according to their maturity characteristics: unripe, physiologically mature, technologically mature and overripe. Unripe and overripe tobacco leaves with no baking value are removed and classified into poles. The amount of tobacco per pole is reduced by 15% compared with the conventional method.

[0031] S3, fresh tobacco leaves are properly loaded on the kang: physiologically mature tobacco leaves are loaded on the low-temperature layer, and technologically mature tobacco leaves are loaded on the high-temperature layer. Each standard intensive flue-curing room can load 350 tobacco rods;

[0032] S4, reduce excess moisture on the surface of tobacco leaves: After the tobacco is loaded in the flue-curing room, open the air inlet and run the circulating fan at high speed for 2 to 3 hours to reduce excess moisture on the surface of tobacco leaves in the flue-curing room;

[0033] S5, baking: one fast and two slow baking technology is used in the early stage of yellowing, and three slow baking technology is used in the middle and late stages of yellowing; two low and one slow baking technology is used in the color fixing stage; one low and one slow baking technology is used in the dry tendon stage;

[0034] The one fast and two slow baking technology used in the early stage of yellowing refers to the use of fast heating, slow dehumidification and slow yellowing baking technology in the early stage of yellowing to reduce the loss of intrinsic substances and water loss of tobacco leaves, increase the yellowing temperature of tobacco leaves, and promote sufficient preheating of tobacco leaves; the specific operation is as follows: after ignition, the dry-bulb temperature is raised to 33.0°C and the wet-bulb temperature is 32.5-33.0°C at a heating rate of 1°C / h, and the tobacco leaves are baked at a steady temperature for 2 hours; thereafter, the dry-bulb temperature is raised to 36.0°C and the wet-bulb temperature is 35.5-36.0°C at a heating rate of 1°C / h, and the tobacco leaves are baked at a steady temperature for 6 hours, until the high-temperature layer of tobacco leaves turns 10% to 20% yellow.

[0035] The three-slow baking technology is used in the middle and late stages of yellowing, which means that the slow heating, slow dehumidification and slow yellowing are used in the middle and late stages of yellowing to make the tobacco leaves fully soften, wither and turn yellow; the specific operation is as follows: the dry bulb temperature is raised to 38.0-39.0℃ at a rate of 1℃ / 3h, the wet bulb temperature is 37.0-38.0℃, and the temperature is kept constant for 20h until the high temperature layer of tobacco leaves turns 50%-60% yellow; the dry bulb temperature is raised to 40.0-45.0℃ at a rate of 1℃ / 4h, and the wet bulb temperature is raised to 40.0-45.0℃. 1.0℃, wet-bulb temperature 36.5~37.5℃, bake at steady temperature for 15h, the tobacco leaves turn 70% to 80% yellow; then, lower the wet-bulb temperature to 35.5~36.5℃, bake at steady temperature for 5h; then, control the wet-bulb temperature unchanged, increase the dry-bulb temperature to 42.0~43.0℃ at a heating rate of 1℃ / 3~5h, bake at steady temperature for 14h, until more than 98% of the tobacco leaves in the high-temperature layer turn yellow and blue, and fully soften and wilt.

[0036] The two-low-one-slow baking technology is used during the color fixing period, which means that the low-temperature, low-humidity and slow temperature-raising color fixing baking technology is used during the color fixing period to make the tobacco leaves yellow and reduce ash. The specific operation is as follows: the dry-bulb temperature is raised to 44.0-45.0℃ and the wet-bulb temperature is 35.0-36.0℃ at a heating rate of 1℃ / 5h, and the temperature is kept constant for 10h until the tobacco leaves are completely yellow, some of the main tendons are white, and the leaves are more than 1 / 10 dry; then, the temperature is raised at 1℃ / 5h. Speed, raise the dry-bulb temperature to 47.0-49.0℃, wet-bulb temperature to 36.0-37.5℃, and bake at a steady temperature for 12h, until the main veins of the tobacco leaves in the high-temperature layer basically turn yellow, and the tobacco leaves are more than 1 / 2 dry; then, increase the temperature at a rate of 1℃ / 4h, raise the dry-bulb temperature to 53.0-54.0℃, wet-bulb temperature to 38.0-39.0℃, and bake at a steady temperature for 12h, until the tobacco leaves on the whole kang are completely dry, and the main tendons are more than 1 / 3 dry.

[0037] The "low and slow" baking technology is used in the dry-stem stage, which means that the low-temperature and slow-heating dry-stem aroma-preserving baking technology is used in the dry-stem stage to promote the drying of tobacco stems and improve the oil quality of tobacco leaves after baking. The specific operation is as follows: at a heating rate of 1℃ / 3h, the dry-bulb temperature is raised to 60.0℃, the wet-bulb temperature is 39.0~40.0℃, and the temperature is kept constant for 10h, and the tobacco stems are dried by more than 2 / 3; then, at a heating rate of 1℃ / 2h, the dry-bulb temperature is raised to 65.0℃, the wet-bulb temperature is 40.0~41.0℃, and the temperature is kept constant until the tobacco leaves are completely dry.

[0038] Example 2.

[0039] 1. A method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine, characterized by comprising:

[0040] S1. Harvesting of fresh tobacco leaves at the right maturity: Most of the harvested fresh tobacco leaves are physiologically mature and technologically mature. The yellowing degree of the leaves is 10% to 20% lower than normal. The hairs have fallen off, and the main veins and side veins are shiny. The picking time should be chosen on cloudy days with little rain.

[0041] S2, classification and reasonable arrangement of fresh tobacco leaves: fresh tobacco leaves are roughly divided into four categories according to their maturity characteristics: unripe, physiologically mature, technologically mature and overripe. Unripe and overripe tobacco leaves with no baking value are removed and classified into rods. The amount of tobacco per rod is reduced by 10% compared with the conventional method.

[0042] S3, fresh tobacco leaves are properly loaded on the kang: physiologically mature tobacco leaves are loaded on the low-temperature layer, and technologically mature tobacco leaves are loaded on the high-temperature layer. Each standard intensive flue-curing room is loaded with 300 tobacco rods;

[0043] S4, reduce excess moisture on the surface of tobacco leaves: after the tobacco is loaded in the flue-curing room, open the air inlet and run the circulating fan at high speed for 2 hours to reduce excess moisture on the surface of tobacco leaves in the flue-curing room;

[0044] S5, baking: one fast and two slow baking technology is used in the early stage of yellowing, and three slow baking technology is used in the middle and late stages of yellowing; two low and one slow baking technology is used in the color fixing stage; one low and one slow baking technology is used in the dry tendon stage;

[0045] The one fast and two slow baking technology used in the early stage of yellowing refers to the use of fast heating, slow dehumidification and slow yellowing baking technology in the early stage of yellowing to reduce the loss of intrinsic substances and water loss of tobacco leaves, increase the yellowing temperature of tobacco leaves, and promote sufficient preheating of tobacco leaves; the specific operation is as follows: after ignition, the dry-bulb temperature is raised to 33.0°C and the wet-bulb temperature is 32.5-33.0°C at a heating rate of 1°C / h, and the tobacco leaves are baked at a steady temperature for 2 hours; thereafter, the dry-bulb temperature is raised to 36.0°C and the wet-bulb temperature is 35.5-36.0°C at a heating rate of 1°C / h, and the tobacco leaves are baked at a steady temperature for 6 hours, until the high-temperature layer of tobacco leaves turns 10% to 20% yellow.

[0046] The three-slow baking technology is used in the middle and late stages of yellowing, which means that the slow heating, slow dehumidification and slow yellowing are used in the middle and late stages of yellowing to make the tobacco leaves fully soften, wither and turn yellow; the specific operation is as follows: the dry bulb temperature is raised to 38.0-39.0℃ at a rate of 1℃ / 2h, the wet bulb temperature is 37.0-38.0℃, and the temperature is kept constant for 10h until the high temperature layer of tobacco leaves turns 50%-60% yellow; the dry bulb temperature is raised to 40.0-45.0℃ at a rate of 1℃ / 3h. 1.0℃, wet-bulb temperature 36.5~37.5℃, bake at steady temperature for 10h, the tobacco leaves turn 70% to 80% yellow; then, lower the wet-bulb temperature to 35.5~36.5℃, bake at steady temperature for 4h; then, control the wet-bulb temperature unchanged, increase the dry-bulb temperature to 42.0~43.0℃ at a heating rate of 1℃ / 3~5h, bake at steady temperature for 10h, until more than 98% of the tobacco leaves in the high-temperature layer turn yellow and blue, and fully soften and wilt.

[0047] The two-low-one-slow baking technology is used during the color fixing period, which means that the low-temperature, low-humidity and slow temperature-raising color fixing baking technology is used during the color fixing period to make the tobacco leaves yellow and reduce ash. The specific operation is as follows: at a heating rate of 1℃ / 4h, the dry bulb temperature is raised to 44.0-45.0℃, the wet bulb temperature is 35.0-36.0℃, and the temperature is kept constant for 6h until the tobacco leaves are completely yellow, some of the main tendons are white, and the leaves are more than 1 / 10 dry; then, at a heating rate of 1℃ / 4h, the leaves are dried. Degrees, raise the dry-bulb temperature to 47.0-49.0℃, the wet-bulb temperature to 36.0-37.5℃, and bake at a steady temperature for 8 hours until the main veins of the tobacco leaves in the high-temperature layer basically turn yellow and the tobacco leaves are more than 1 / 2 dry; then, increase the dry-bulb temperature to 53.0-54.0℃, the wet-bulb temperature to 38.0-39.0℃ at a heating rate of 1℃ / 3-4h, and bake at a steady temperature for 10 hours until the tobacco leaves on the whole kang are completely dry and the main tendons are more than 1 / 3 dry.

[0048] The "low and slow" baking technology is used in the dry-stem stage, which means that the low-temperature and slow-heating dry-stem aroma-preserving baking technology is used in the dry-stem stage to promote the drying of tobacco stems and improve the oil quality of tobacco leaves after baking. The specific operation is as follows: at a heating rate of 1℃ / 2h, the dry-bulb temperature is raised to 60.0℃, the wet-bulb temperature is 39.0~40.0℃, and the temperature is kept constant for 6h, and the tobacco stems are dried by more than 2 / 3; then, at a heating rate of 1℃ / 1h, the dry-bulb temperature is raised to 65.0℃, the wet-bulb temperature is 40.0~41.0℃, and the temperature is kept constant until the tobacco leaves are completely dry.

[0049] Example 3.

[0050] 1. A method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine, characterized by comprising:

[0051] S1. Harvesting of fresh tobacco leaves at the right maturity: Most of the harvested fresh tobacco leaves are physiologically mature and technologically mature. The yellowing degree of the leaves is 10% to 20% lower than normal. The hairs have fallen off, and the main veins and side veins are shiny. The picking time should be chosen on cloudy days with little rain.

[0052] S2, classification and reasonable arrangement of fresh tobacco leaves: fresh tobacco leaves are roughly divided into four categories according to their maturity characteristics: unripe, physiologically mature, technologically mature and overripe. Unripe and overripe tobacco leaves with no baking value are removed and classified into rods. The amount of tobacco per rod is reduced by 3% compared with the conventional method.

[0053] S3, fresh tobacco leaves are properly loaded on the kang: physiologically mature tobacco leaves are loaded on the low-temperature layer, and technologically mature tobacco leaves are loaded on the high-temperature layer. Each standard intensive flue-curing room is loaded with 330 tobacco rods;

[0054] S4, reduce excess moisture on the surface of tobacco leaves: After the tobacco is loaded in the flue-curing room, open the air inlet and run the circulating fan at high speed for 2 to 3 hours to reduce excess moisture on the surface of tobacco leaves in the flue-curing room;

[0055] S5, baking: one fast and two slow baking technology is used in the early stage of yellowing, and three slow baking technology is used in the middle and late stages of yellowing; two low and one slow baking technology is used in the color fixing stage; one low and one slow baking technology is used in the dry tendon stage;

[0056] The one fast and two slow baking technology used in the early stage of yellowing refers to the use of fast heating, slow dehumidification and slow yellowing baking technology in the early stage of yellowing to reduce the loss of intrinsic substances and water loss of tobacco leaves, increase the yellowing temperature of tobacco leaves, and promote sufficient preheating of tobacco leaves; the specific operation is as follows: after ignition, the dry-bulb temperature is raised to 33.0°C and the wet-bulb temperature is 32.5-33.0°C at a heating rate of 1°C / h, and the tobacco leaves are baked at a steady temperature for 1.5 hours; thereafter, the dry-bulb temperature is raised to 36.0°C and the wet-bulb temperature is 35.5-36.0°C at a heating rate of 1°C / h, and the tobacco leaves are baked at a steady temperature for 6 hours, until the high-temperature layer of tobacco leaves turns 10% to 20% yellow.

[0057] The three-slow baking technology is used in the middle and late stages of yellowing, which means that the slow heating, slow dehumidification and slow yellowing are used in the middle and late stages of yellowing to make the tobacco leaves fully soften, wither and turn yellow; the specific operation is as follows: the dry bulb temperature is raised to 38.0-39.0℃ at a rate of 1℃ / 2-3h, the wet bulb temperature is 37.0-38.0℃, and the temperature is kept constant for 15h until the high temperature layer of tobacco leaves turns 50% to 60% yellow; the dry bulb temperature is raised to 40.0-40.0℃ at a rate of 1℃ / 3-4h. 41.0℃, wet-bulb temperature 36.5~37.5℃, bake at steady temperature for 13h, the tobacco leaves turn 70% to 80% yellow; then, lower the wet-bulb temperature to 35.5~36.5℃, bake at steady temperature for 4~5h; then, control the wet-bulb temperature unchanged, increase the dry-bulb temperature to 42.0~43.0℃ at a heating rate of 1℃ / 3~5h, bake at steady temperature for 12h, until more than 98% of the tobacco leaves in the high-temperature layer turn yellow and blue, and fully soften and wilt.

[0058] The two-low-one-slow baking technology is used during the color fixing period, which means that the low-temperature, low-humidity and slow temperature-raising color fixing baking technology is used during the color fixing period to make the tobacco leaves yellow and reduce ash. The specific operation is as follows: the dry-bulb temperature is raised to 44.0-45.0℃ and the wet-bulb temperature is 35.0-36.0℃ at a heating rate of 1℃ / 4-5h, and the temperature is kept constant for 8h until the tobacco leaves are completely yellow, some of the main tendons are white, and the leaves are more than 1 / 10 dry; then, the temperature is raised to 1℃ / 4-5h. Heat the dry-bulb temperature to 47.0-49.0℃ and the wet-bulb temperature to 36.0-37.5℃ at a heating rate, and bake at a steady temperature for 10 hours until the main veins of the tobacco leaves in the high-temperature layer basically turn yellow and the tobacco leaves are more than 1 / 2 dry; then, heat the dry-bulb temperature to 53.0-54.0℃ and the wet-bulb temperature to 38.0-39.0℃ at a heating rate of 1℃ / 3-4h, and bake at a steady temperature for 11 hours until the tobacco leaves on the whole kang are completely dry and the main tendons are more than 1 / 3 dry.

[0059] The "low and slow" baking technology is used in the dry-stem stage, which means that the low-temperature and slow-heating dry-stem aroma-preserving baking technology is used in the dry-stem stage to promote the drying of tobacco stems and improve the oil quality of tobacco leaves after baking. The specific operation is as follows: at a heating rate of 1℃ / 2~3h, the dry-bulb temperature is raised to 60.0℃, the wet-bulb temperature is 39.0~40.0℃, and the temperature is kept constant for 8h, and the tobacco stems are dried by more than 2 / 3; then, at a heating rate of 1℃ / 1~2h, the dry-bulb temperature is raised to 65.0℃, the wet-bulb temperature is 40.0~41.0℃, and the temperature is kept constant until the tobacco leaves are completely dry.

[0060] At the same time, the method of the present invention is used to harvest and flue-cured Yunyan 87 tobacco leaves with high rainfall and low sunshine throughout the growth period. The experiment was carried out in the tobacco-growing area of ​​Guizhou Province in 2024. The test flue-cured tobacco variety was Yunyan 87, and the middle and lower tobacco leaves were used as test materials.

[0061] like Figure 1-2As shown, the quality of tobacco leaves after Yunyan 87 baking by the method of the present invention is better. At the same time, after statistical analysis of tobacco leaf data from multiple regions, the data in Tables 1 to 3 are as follows;

[0062] Table 1 Effects of different treatments on the appearance quality of flue-cured tobacco leaves

[0063]

[0064] Table 2 Effects of different treatments on the softness and single leaf weight of flue-cured tobacco leaves

[0065]

[0066] Note: Different lowercase letters indicate significant differences among different treatments at the 5% level.

[0067] Table 3 Effects of different treatments on the grade structure of flue-cured tobacco leaves (%)

[0068]

[0069] The test data in the above table prove that the method of harvesting and curing tobacco leaves with more rain and less sunshine during the whole growth period can: 1. Improve the appearance quality of tobacco leaves after curing, especially the oil content and softness index of tobacco leaves; 2. Reduce the loss of internal substances in tobacco leaves and increase the weight of single tobacco leaves after curing; 3. Improve the grade structure of tobacco leaves after curing and reduce the proportion of green dregs and ash-covered tobacco. It has good practical value and can be promoted.

Claims

1. A method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine, characterized in that: include: S1, harvesting of fresh tobacco leaves at the right maturity: Most of the harvested fresh tobacco leaves are physiologically mature and technologically mature, with the yellowing degree of the leaves being 10% to 20% lower than normal, the hairs falling off, and the main veins and branch veins being shiny; S2, classification and reasonable arrangement of fresh tobacco leaves: fresh tobacco leaves are roughly divided into four categories according to their maturity characteristics: unripe, physiologically mature, technologically mature and overripe. Unripe and overripe tobacco leaves with no baking value are removed and classified into poles. The amount of tobacco per pole is reduced by 10% to 15% compared with the conventional method. S3, fresh tobacco leaves are properly loaded on the kang: physiologically mature tobacco leaves are loaded on the low-temperature layer, and technologically mature tobacco leaves are loaded on the high-temperature layer. Each standard intensive flue-curing room is loaded with 300-350 tobacco rods; S4, reduce excess moisture on the surface of tobacco leaves: After the flue-curing room is loaded with tobacco, open the air inlet and run the circulating fan at high speed for 2-3 hours to reduce excess moisture on the surface of tobacco leaves in the flue-curing room; S5, baking: the one fast and two slow baking technology is adopted in the early stage of yellowing, and the three slow baking technology is adopted in the middle and late stages of yellowing; the two lows and one slow baking technology is adopted in the color fixing stage; the one low and one slow baking technology is adopted in the dry tendon stage; the one fast and two slow baking technology adopted in the early stage of yellowing refers to the fast heating, slow dehumidification, and slow yellowing baking technology adopted in the early stage of yellowing to reduce the loss of internal substances and water loss of tobacco leaves, increase the yellowing temperature of tobacco leaves, and promote the full preheating of tobacco leaves; the three slow baking technology is adopted in the middle and late stages of yellowing, which refers to the slow heating, slow dehumidification, and slow yellowing adopted in the middle and late stages of yellowing to promote the full softening, withering and yellowing of tobacco leaves; the two lows and one slow baking technology is adopted in the color fixing stage, which refers to the low temperature, low humidity, slow heating and color fixing baking technology adopted in the color fixing stage to promote the yellow color of tobacco leaves to be fixed and reduce ash; the one low and one slow baking technology is adopted in the dry tendon stage, which refers to the low temperature, slow heating, dry tendon and fragrance preservation baking technology adopted in the dry tendon stage to promote the drying of tobacco tendons and improve the oil quality of tobacco leaves after baking.

2. The method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine according to claim 1, characterized in that: The specific operation of the one fast and two slow baking technology used in the early stage of yellowing is as follows: after ignition, the dry bulb temperature is raised to 33.0°C and the wet bulb temperature is 32.5~33.0°C at a heating rate of 1°C / h, and the baking is carried out at a steady temperature for 1~2 hours; thereafter, the dry bulb temperature is raised to 36.0°C and the wet bulb temperature is 35.5~36.0°C at a heating rate of 1°C / h, and the baking is carried out at a steady temperature for 5~6 hours, until the high-temperature layer of tobacco leaves turns 10% to 20% yellow.

3. The method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine according to claim 2, characterized in that: The specific operation of the three-slow baking technology in the middle and late stages of yellowing is as follows: raise the dry-bulb temperature to 38.0~39.0℃ and the wet-bulb temperature to 37.0~38.0℃ at a rate of 1℃ / 2~3 h, and bake at a steady temperature for 10~20 h, until the tobacco leaves in the high-temperature layer turn 50% to 60% yellow; raise the dry-bulb temperature to 40.0~41.0℃ and the wet-bulb temperature to 36.5~37.5℃ at a rate of 1℃ / 3~4 h, and bake at a steady temperature for 10~15 h, until the tobacco leaves turn 70% to 80% yellow; then, lower the wet-bulb temperature to 35.5~36.5℃, and bake at a steady temperature for 4~5 h; then, control the wet-bulb temperature to remain unchanged, raise the dry-bulb temperature to 42.0~43.0℃ at a rate of 1℃ / 3~5 h, and bake at a steady temperature for 10~14 h, until more than 98% of the tobacco leaves in the high-temperature layer turn yellow and have blue veins, and fully soften and wilt.

4. The method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine according to claim 3, characterized in that: The specific operation of the two-low-one-slow baking technology adopted in the color fixing period is as follows: the dry-bulb temperature is raised to 44.0-45.0°C and the wet-bulb temperature is 35.0-36.0°C at a heating rate of 1°C / 4-5 h, and the tobacco leaves are baked at a steady temperature for 6-10 h, until the tobacco leaves are completely yellow, some of the main tendons are white, and the leaves are more than 1 / 10 dry; thereafter, the dry-bulb temperature is raised to 47.0-49.0°C and the wet-bulb temperature is 36.0-37.5°C at a heating rate of 1°C / 4-5 h, and the tobacco leaves are baked at a steady temperature for 8-12 h, until the main veins of the tobacco leaves in the high-temperature layer are basically yellow, and the tobacco leaves are more than 1 / 2 dry; thereafter, the dry-bulb temperature is raised to 53.0-54.0°C and the wet-bulb temperature is 38.0-39.0°C at a heating rate of 1°C / 3-4 h, and the tobacco leaves are baked at a steady temperature for 10-12 h, until the tobacco leaves on the whole kang are completely dry and the main tendons are more than 1 / 3 dry.

5. The method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine according to claim 4, characterized in that: The specific operation of the low-slow baking technology adopted in the tobacco leaf drying period is as follows: the dry-bulb temperature is raised to 60.0°C and the wet-bulb temperature is 39.0~40.0°C at a heating rate of 1°C / 2~3 h, and the tobacco leaf is baked at a steady temperature for 6~10 h until the tobacco leaf is more than 2 / 3 dry; thereafter, the dry-bulb temperature is raised to 65.0°C and the wet-bulb temperature is 40.0~41.0°C at a heating rate of 1°C / 1~2 h, and the tobacco leaf is baked at a steady temperature until the whole kang is completely dry.

6. The method for harvesting and curing tobacco leaves in the whole growth period with high rainfall and low sunshine according to claim 1, characterized in that: In step S1, try to choose cloudy and rainy weather for smoke collection.

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