A method for wilting and softening tobacco leaves and baking

Abstract

The present invention discloses a method for withering and softening tobacco leaves and baking, which comprises the following steps: S1, harvesting mature fresh tobacco leaves: harvesting mature fresh tobacco leaves by parts according to the mature standard of fresh tobacco leaves; S2, classifying and stringing fresh tobacco leaves: preliminarily judging the quality and baking characteristics of fresh tobacco leaves according to the mature characteristics and texture characteristics of fresh tobacco leaves; S3, withering fresh tobacco leaves by light quality stress: subjecting the strung under-ripe, physiologically mature and technologically mature fresh tobacco leaves to withering by light quality stress, and the withering by light quality stress is to irradiate the fresh tobacco leaves on the curing barn with three light qualities of blue light, yellow light and purple light, each light quality is irradiated for 4-5 hours, and the three light qualities are alternately irradiated; S4, classifying and loading into the baking barn; S5, baking; By classifying and stringing fresh tobacco leaves, grading according to the quality of tobacco leaves, subjecting them to withering by light quality stress, then classifying and loading into the baking barn and adopting a three-stage baking process for scientific baking, the present invention can effectively shorten the baking time and improve the internal quality of the baked tobacco leaves.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue-cured tobacco modulation, and particularly relates to a method for wilting and softening tobacco leaves and baking. Background Art

[0002] At present, tobacco leaf baking is one of the weak links in China's flue-cured tobacco production, and the baking quality directly affects the level of cigarettes. The tobacco leaves in bulk curing barn are prone to phenomena such as ash hanging, stiffness, non-expansion and non-softness, which are difficult to meet the requirements of "Chinese-style cigarettes" for high-quality tobacco leaf raw materials, and have become an important problem to be solved urgently in tobacco leaf production. The essence of tobacco leaf baking is the unity of the process of forming the appearance quality of tobacco leaf dehydration and drying and the process of forming the internal quality of physiological and biochemical changes. The appearance quality indexes of the baked tobacco leaves such as color, tissue structure, oil content, etc. reflect the quality of the tobacco leaf internal quality to a certain extent.

[0003] The dynamics of wilting and softening of harvested tobacco leaves are closely related to the appearance quality and internal quality; the wilting and softening conditions not only affect the physiological and biochemical and material metabolism changes of tobacco leaves during baking, but also affect the quality and economic value of the baked tobacco leaves. Although there are reports at present that pre-wilting treatment before baking can shorten the baking time of tobacco leaves and improve the quality of tobacco leaves, there are no reports on promoting the wilting of fresh tobacco leaves and improving the baking quality of tobacco leaves by light quality stress. Treating fresh tobacco leaves with light quality stress can not only accelerate the senescence process of tobacco leaves, promote the transformation and synthesis of their internal substances, but also improve the quality of the baked tobacco leaves, especially for the upper tobacco leaves, and the effect is more significant. It is reported that the quality of the baked tobacco leaves is better after the fresh tobacco leaves with good maturity and quality are reasonably modulated by the supporting baking process. However, the traditional classification of fresh tobacco mainly makes a simple judgment through maturity, lacking systematicness and integrity; moreover, the baking operation mainly relies on the traditional three-stage baking process and production experience, with a long baking time, high energy consumption, relatively large baking losses, and more loss of aroma substances in the baked tobacco leaves. The present invention comprehensively judges the quality and baking characteristics of tobacco leaves by combining the maturity characteristics and texture characteristics (glandular hair secretions and oil content, softness, leaf identity thickness and moisture content) of fresh tobacco leaves, and conducts classified and layered tobacco loading and scientific baking, which is more scientific and systematic, and the baking effect is remarkable. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for wilting and softening tobacco leaves and baking, which can shorten the baking time and improve the internal quality of the baked tobacco leaves.

[0005] The technical solution of the present invention is as follows:

[0006] A method for wilting and softening tobacco leaves and baking, which comprises the following steps:

[0007] S1. Harvesting fresh tobacco leaves when mature: Harvesting the fresh tobacco leaves when mature by parts according to the fresh tobacco leaf maturity standard;

[0008] S2. Classification and Bunching of Fresh Tobacco Leaves: Based on the maturity characteristics and texture characteristics of fresh tobacco leaves, preliminarily judge the quality and baking characteristics of the tobacco leaves.

[0009] S3. Light Quality Stress Wilting of Fresh Tobacco Leaves: Subject the bunched fresh tobacco leaves at the under-ripe, physiologically mature, and technologically mature stages to light quality stress wilting. Since the senescence of the fully ripe and over-ripe fresh tobacco leaves is relatively severe, they are not subjected to light quality stress. The light quality stress wilting is to irradiate the fresh tobacco leaves on the curing barn with three light qualities: blue light, yellow light, and purple light.

[0010] S4. Classification and Loading of Fresh Tobacco Leaves into the Kiln: Divide the loading chamber into a high-temperature area and a low-temperature area according to the air flow movement mode of the curing barn. Load the over-ripe and fully ripe tobacco leaves into the high-temperature area, and load the under-ripe and physiologically mature tobacco leaves into the low-temperature area. Load the technologically mature tobacco leaves into the remaining space of the loading chamber.

[0011] S5. Baking of Fresh Tobacco Leaves: Adopt a three-stage baking process for baking. The baking process is divided into three stages. The first stage is the wilting and softening stage with yellow leaves and soft veins, the second stage is the dry leaf and yellow vein stage, and the third stage is the dry vein stage.

[0012] In the above step S1, the judgment standard for the maturity of fresh tobacco leaves refers to the national standard "Technical Regulations for Flue-cured Tobacco Baking" (GB / T 23219-2008). The maturity characteristics include the basic conditions such as the appearance color of the tobacco leaves, the leaf surface morphology and glossiness, the fading and whitening of the main and branch veins, the shedding of glandular hairs, the neatness of the base of the tobacco leaves, and the maturity spots of the tobacco leaves.

[0013] In the above step S2, the texture characteristics of fresh tobacco leaves include the basic conditions such as the glandular hair secretions and oil content on the leaf surface, the softness, the thickness of the leaf identity, and the moisture content.

[0014] In the above step S3, each of the blue light, yellow light, and purple light is irradiated for 4 - 5 hours, and the three light qualities are alternately irradiated. The total light quality stress time is 12 - 15 hours, making the tips and edges of the fresh tobacco leaves soft, the leaves slightly soft, and the water loss rate 5% - 10%.

[0015] In the above step S5, the wilting and softening stage with yellow leaves and soft veins includes the following steps:

[0016] S5-1. For the tobacco leaves placed after step S4, before ignition, circulate at a high fan speed for 1 - 3 hours; after ignition, start the fan at a low speed and increase the temperature at a rate of 1°C per hour to 32 - 33°C, with the wet-bulb temperature stabilized at 31 - 32°C, and bake at a constant temperature for 3 - 5 hours until the tobacco leaves in the high-temperature layer turn 1 - 2 tenths yellow.

[0017] S5-2. Keep the fan at a low speed and increase the temperature at a rate of 1°C per hour to 35 - 36°C, with the wet-bulb temperature stabilized at 34 - 35°C, and bake at a constant temperature for 3 - 5 hours until the tobacco leaves in the high-temperature layer turn 2 - 3 tenths yellow.

[0018] S5-3. Maintain the circulating fan at a medium wind speed, raise the temperature to 38-39°C at a rate of 1°C per hour, stabilize the wet-bulb temperature at 36-37°C, and bake at a steady temperature for 15-25 hours until the tobacco leaves in the high-temperature layer turn 70% to 80% yellow, with the leaves withering and becoming soft;

[0019] S5-4. Start the circulating fan at medium or high wind speed, raise the temperature to 40-41°C at a rate of 1°C every 2 hours, stabilize the wet bulb temperature at 36-37°C, and bake at a steady temperature for 10-15 hours until the high-temperature layer tobacco leaves turn 80% to 90% yellow and the main veins become soft;

[0020] S5-5. Enable the circulating fan at high wind speed, raise the temperature to 43-44°C at a rate of 1°C every 3 hours, stabilize the wet-bulb temperature at 35-37°C, bake at a steady temperature for 10-15 hours, and control the moisture until the tobacco leaves in the high-temperature layer are fully withered and softened, and the yellow leaves and hook tips are curled.

[0021] In the above step S5, the dry slice yellow tendon stage includes the following steps:

[0022] S6-1. After the tobacco leaves wither and become soft, keep the circulating fan at high speed, raise the temperature to 47-48℃ at a rate of 1℃ every 3 hours, stabilize the wet bulb temperature at 37-38℃, and bake at a steady temperature for 10-15 hours until more than 95% of the main ribs of the tobacco leaves in the high temperature layer turn yellow, and the tobacco leaves are half dry and small rolls;

[0023] S6-2. Maintain the circulating fan at a medium wind speed, raise the temperature to 50-51°C at a rate of 1°C every 2 hours, stabilize the wet-bulb temperature at 38-39°C, and bake at a steady temperature for 6-8 hours until the main ribs of the tobacco leaves are completely yellow and obviously shrunk, and the leaves are more than 2 / 3 dry;

[0024] S6-3. Maintain the circulating fan at medium wind speed, raise the temperature to 53-54°C at a rate of 1°C every 2 hours, stabilize the wet-bulb temperature at 38-40°C, and bake at a steady temperature for 10-15 hours until the tobacco leaves are completely dry and rolled into large rolls, and the main tendons gradually change from yellow to purple-brown.

[0025] In the above step S5, the dry tendon stage includes the following steps:

[0026] S7-1. After the yellow rib stage of the dry leaves is completed, keep the circulating fan at a low speed, raise the temperature to 57-60℃ at a rate of 1℃ per hour, stabilize the wet bulb temperature at 39-40℃, and bake at a stable temperature for 6-10 hours until the main ribs of the high-temperature layer of tobacco leaves are more than 2 / 3 dry;

[0027] S7-2. Keep the circulating fan at a low speed and continue to raise the temperature to 64-68°C at a rate of 1°C per hour. Keep the wet-bulb temperature stable at 39-40°C. Bake at a steady temperature for 15-20 hours until the main tendons of the tobacco leaves on the kang are completely dry.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] The invention discloses a method for withering, softening and baking tobacco leaves, which classifies and compiles fresh tobacco leaves, grades them according to their quality, and withers them under light stress, and then classifies them, loads them on a kang, and bakes them using a three-stage baking process. Up to now, the three-stage baking process and experience are mainly used to bake tobacco leaves in flue-cured tobacco production, and the baking time is relatively long. After baking, the tobacco leaves are stiff, the proportion of ash hanging is high, the aroma is insufficient, and the baking loss is large. The invention adopts a three-stage baking process for scientific baking, and the baking process is divided into three stages, the first stage is the withering, softening, yellowing and soft tendons stage, the second stage is the dry yellow tendons stage, and the third stage is the dry tendons stage. The dry bulb temperature, humidity, stable temperature time and wind speed of each baking stage are adjusted to a certain extent. The key dry bulb temperature setting differences are as follows: The first stage is the withering, softening, yellowing and soft tendons stage, which is divided into 5 steps. The withering dry bulb temperature is set to 43-44°C, which is different from the conventional three-stage baking process, which is conducive to reducing green tobacco, stiff tobacco and ash-hanging tobacco; The second stage is the dry yellow tendons stage, which is divided into 3 steps, reducing the dry bulb temperature of 45°C stable temperature baking, and increasing the dry bulb temperature of 50-51°C stable temperature baking, which is conducive to reducing green tobacco; The third stage is the dry tendons stage, which is divided into 2 steps, increasing the dry bulb temperature of 57-60°C stable temperature baking, and extending the baking time of this stable temperature point, shortening the 64-68°C stable temperature baking time, which is conducive to reducing the loss of aroma substances during the dry tendons period. The new tobacco leaf withering, softening and baking technology can promote the transformation of substances during the withering, softening and baking process of the harvested tobacco leaves, and improve the quality of the tobacco leaves after baking. This method has the following benefits:

[0030] 1. It is conducive to the classification, baking and regulation of tobacco leaves, which is conducive to the full withering and softening of tobacco leaves, shortening the baking time by 15 to 30 hours and reducing the baking energy consumption;

[0031] 2. It is conducive to the full degradation of tobacco leaf starch, pigments and other macromolecular substances during the baking process, and improves the intrinsic quality of the tobacco leaves after baking;

[0032] 3. It is conducive to accurately controlling the stage changes of tobacco leaves during the baking process and achieving the goal, and is conducive to accurately controlling the stage water loss of tobacco leaves and preventing tobacco leaves from being burned;

[0033] 4. It is helpful to reduce the loss of tobacco aroma, reduce the proportion of stiff and gray tobacco leaves, and improve the quality of tobacco leaves after curing.

[0034] Other advantages, objects and features of the present invention will be set forth in part in the following description, and in part will be obvious to those skilled in the art upon examination of the following, or may be learned from the practice of the present invention. The objects and other advantages of the present invention may be realized and obtained by the following description. Detailed Description

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the tables in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0036] Example 1. The flue-cured tobacco leaves of Yunyan 87 are baked by a method of withering and softening the tobacco leaves and baking, which includes the following steps:

[0037] S1. Harvesting fresh tobacco leaves at maturity: Harvesting fresh tobacco leaves at maturity by parts according to the standard of fresh tobacco leaf maturity "Technical Regulations for Flue-cured Tobacco Baking" (GBT23219-2008). The maturity characteristics of fresh tobacco leaves include basic conditions such as the appearance color of the tobacco leaves, the leaf surface morphology and glossiness, the fading and whitening of the main and secondary veins, the shedding of glandular hairs, the neatness of the base of the tobacco leaves, and the maturity spots of the tobacco leaves.

[0038] S2. Classifying and stringing (clamping) fresh tobacco leaves: According to the maturity characteristics and texture characteristics of fresh tobacco leaves, initially judge the quality and baking characteristics of the tobacco leaves. Specifically:

[0039] According to the maturity characteristics of fresh tobacco leaves (including basic conditions such as appearance color, leaf surface morphology and glossiness, fading and whitening of the main and secondary veins, shedding of glandular hairs, neatness of the base of the tobacco leaves, and maturity spots of the tobacco leaves) and texture characteristics (including basic conditions such as the secretion of glandular hairs on the leaf surface and the amount of oil, softness, leaf thickness, and moisture content), initially judge the quality and baking characteristics of the tobacco leaves.

[0040] A. Judgment of the maturity of fresh tobacco leaves

[0041] According to the maturity characteristics such as the appearance color of fresh tobacco leaves, the tobacco leaves are classified into under-ripe, physiologically mature, technologically mature, fully ripe, and over-ripe tobacco leaves, and the damaged, diseased and over-ripe tobacco leaves without baking value are removed.

[0042] B. Judgment of the texture characteristics of fresh tobacco leaves

[0043] (1) The amount of glandular hair secretion and oil on the surface of fresh tobacco leaves is divided into 3 grades: more (good), general (medium), and less (bad);

[0044] (2) The softness of fresh tobacco leaves is divided into three grades: soft (good), relatively soft (medium), and hard or brittle (bad).

[0045] (3) The identity thickness of the corresponding parts of fresh tobacco leaves is divided into three grades: moderate (good), thinner or thicker (medium), and thin or thick (bad).

[0046] (4) The moisture content of fresh tobacco leaves is divided into three grades: suitable moisture content is ≥80% and ≤87% (good), relatively suitable moisture content is >76% and <80% or >87% and <92% (medium), and unsuitable moisture content is ≤76% or ≥92% (bad).

[0047] Based on visual inspection and hand feeling, judge the grades of four indicators of fresh tobacco leaves with different maturity levels, including the amount of glandular hair secretions and oil on the surface, softness, identity thickness of the corresponding parts, and moisture content. If three or more judgment indicators of fresh tobacco leaves are in the "good" grade, the quality and baking characteristics of fresh tobacco leaves are defined as the "good" grade; if three or more judgment indicators of fresh tobacco leaves are in the "bad" grade, it is defined as the "bad" grade; the rest are defined as the "medium" grade.

[0048] After classifying the fresh tobacco leaves, string (clip) the tobacco leaves, and then hang them on the tobacco drying racks in the stringing area respectively.

[0049] S3. Light quality stress wilting of fresh tobacco leaves: Subject the under-ripe, physiologically mature, and technologically mature fresh tobacco leaves that have been strung (clipped) to light quality stress wilting. The over-ripe and over-mature fresh tobacco leaves have relatively severe senescence, so they are not subjected to light quality stress; the light quality stress wilting is to irradiate the fresh tobacco leaves on the drying racks with three light qualities of blue light, yellow light, and purple light. Each light quality is irradiated for 4 - 5 hours, and the three light qualities are alternately irradiated. The total light quality stress time is 12 - 15 hours, making the leaf tips and leaf edges soft, the leaves slightly soft, and the water loss rate is 5% - 10%; Through light quality stress treatment, the senescence process of fresh tobacco leaves can be accelerated, the transformation and synthesis of its internal substances can be promoted, and the quality of the cured tobacco leaves can be improved. The wilting states of the middle leaves of Yunyan 87 under different light quality treatments are shown in Table 1:

[0050] Table 1 Wilting states of tobacco leaves under different light quality treatments

[0051]

[0052] S4. Classified loading of fresh tobacco leaves into the baking chamber: Divide the loading chamber into a high-temperature area and a low-temperature area according to the air flow movement mode of the baking chamber. The over-mature and fully mature tobacco leaves are loaded in the high-temperature area, and the under-ripe and physiologically mature tobacco leaves are loaded in the low-temperature area. The remaining space in the loading chamber is loaded with technologically mature tobacco leaves. For fresh tobacco leaves with different maturity levels, they are also divided into three grades of "good", "medium", and "bad" according to the quality and baking characteristics of the tobacco leaves.

[0053] (1) Overripe and fully ripe tobacco leaves are loaded into the curing barn. The overripe tobacco leaves are placed in the high-temperature area of the high-temperature layer, followed by the fully ripe tobacco leaves. The fresh tobacco leaves with "poor" quality and baking characteristics are loaded closest to the high-temperature area, followed by the tobacco leaves with "medium" quality and baking characteristics, and finally the tobacco leaves with "good" quality and baking characteristics.

[0054] (2) Underripe and physiologically mature tobacco leaves are loaded into the curing barn. The underripe tobacco leaves are placed in the low-temperature area of the low-temperature layer, followed by the physiologically mature tobacco leaves. The fresh tobacco leaves with "good" quality and baking characteristics are placed closest to the low-temperature area, followed by the tobacco leaves with "medium" quality and baking characteristics, and finally the tobacco leaves with "poor" quality and baking characteristics.

[0055] (3) For technologically mature tobacco leaves, the fresh tobacco leaves with "poor" quality and baking characteristics are placed close to the high-temperature area of the high-temperature layer, followed by the tobacco leaves with "medium" quality and baking characteristics, and finally the tobacco leaves with "good" quality and baking characteristics.

[0056] S5. Baking of fresh tobacco leaves: The three-stage baking process is adopted for baking. The baking process is divided into three stages. The first stage is the withering and softening stage of yellow leaves and soft veins, the second stage is the stage of dry leaves and yellow veins, and the third stage is the dry vein stage. The details are as follows:

[0057] The first stage, the withering and softening stage of yellow leaves and soft veins, includes 5 steps. The specific steps are as follows:

[0058] Step 1, before ignition, the circulation fan runs at high speed for 1 - 3 hours. After ignition, the circulation fan is turned to low speed, and the temperature is raised at a rate of 1°C per hour to 32 - 33°C, with the wet-bulb temperature at 31 - 32°C. Keep the temperature stable for 3 - 5 hours until the tobacco leaves in the high-temperature layer turn 1 - 2 degrees yellow. This is the first step of the withering and softening stage of yellow leaves and soft veins.

[0059] Step 2, keep the circulation fan at low speed, and raise the temperature at a rate of 1°C per hour to 35 - 36°C, with the wet-bulb temperature at 34 - 35°C. Keep the temperature stable for 3 - 5 hours until the tobacco leaves in the high-temperature layer turn 2 - 3 degrees yellow. This is the second step of the withering and softening stage of yellow leaves and soft veins.

[0060] Step 3, keep the circulation fan at medium speed, and raise the temperature at a rate of 1°C per hour to 38 - 39°C, with the wet-bulb temperature at 36 - 37°C. Keep the temperature stable for 15 - 25 hours until the tobacco leaves in the high-temperature layer turn 7 - 8 degrees yellow and the leaves wither and soften. This is the third step of the withering and softening stage of yellow leaves and soft veins.

[0061] Step 4, turn on the circulation fan at medium or high speed, and raise the temperature at a rate of 1°C every 2 hours to 40 - 41°C, with the wet-bulb temperature at 36 - 37°C. Keep the temperature stable for 10 - 15 hours until the tobacco leaves in the high-temperature layer turn 8 - 9 degrees yellow and the main veins soften. This is the fourth step of the withering and softening stage of yellow leaves and soft veins.

[0062] Step 5. Enable the circulating fan at high wind speed, raise the temperature to 43-44°C at a rate of 1°C every 3 hours, with a wet-bulb temperature of 35-37°C. Bake at a steady temperature for 10-15 hours, controlling the moisture until the tobacco leaves in the high-temperature layer are fully withered and softened, with yellow leaves and curled edges. This is step 5 of withering and softening of tobacco leaves and soft tendons.

[0063] The second stage, the dry slice yellow tendon stage, includes 3 steps, the specific steps are as follows:

[0064] The first step is to maintain the circulating fan at a high wind speed, raise the temperature to 47-48°C at a rate of 1°C every 3 hours, with a wet-bulb temperature of 37-38°C, and bake at a steady temperature for 10-15 hours until more than 95% of the main tendons of the tobacco leaves in the high-temperature layer have basically turned yellow, and the leaves are half-dry and small rolled. This is the first step of the yellowing of the tobacco leaves. This stage is both the drying stage and the yellowing stage.

[0065] The second step is to maintain the circulating fan at medium wind speed, raise the temperature to 50-51°C at a rate of 1°C every 2 hours, with a wet-bulb temperature of 38-39°C, and bake at a steady temperature for 6-8 hours until the main veins of the tobacco leaves on the whole kang are completely yellow and noticeably shrunk, and the leaves are more than 2 / 3 dry, which is the second step of the tobacco leaf drying process. This stage is both the drying stage and the yellowing stage.

[0066] The third step is to maintain the circulating fan at medium wind speed, raise the temperature to 53-54°C at a rate of 1°C every 2 hours, with a wet-bulb temperature of 38-40°C, and bake at a steady temperature for 10-15 hours until the tobacco leaves are completely dry and rolled into large rolls, and the main veins gradually change from yellow to purple-brown, which is the third step of the yellow veins of the dried tobacco leaves. This stage is both the drying stage and the yellow vein stage.

[0067] The third stage, the dry muscle stage, includes two steps, the specific steps are as follows:

[0068] The first step is to maintain the circulating fan at a low wind speed, raise the temperature to 57-60°C at a rate of 1°C per hour, with a wet-bulb temperature of 39-40°C, and bake at a steady temperature for 6-10 hours until the main tendons of the tobacco leaves in the high-temperature layer are more than 2 / 3 dry. This is the first step in the tobacco leaf drying stage.

[0069] The second step is to maintain the circulating fan at a low wind speed, raise the temperature to 64-68°C at a rate of 1°C per hour, with a wet-bulb temperature of 39-40°C, and bake at a steady temperature for 15-20 hours until the main tendons of the tobacco leaves on the kang are completely dry. This is the second step of the tobacco leaf drying stage.

[0070] Example 2. The middle tobacco leaves of Yunyan 87 were baked using two baking processes: conventional baking (traditional three-stage baking) and new technology baking (the method described in the present invention): the energy consumption of baking with different treatments, the content of starch and plastid pigments in the tobacco leaves during baking, the appearance quality of the tobacco leaves after baking, the grade structure, the aroma component content, the chemical component content and the sensory quality were compared. The results are shown in Table 2-7.

[0071] Table 2 Comparison of tobacco leaf baking time and energy consumption cost under different treatments

[0072]

[0073] Note: The electricity price is 0.50 yuan per degree, and the price of coal is 1.30 yuan per kilogram;

[0074] Different lowercase letters between different baking treatments indicate significant differences at the 5% level.

[0075] Table 3 Comparison of starch and plastid pigment contents in tobacco leaves during baking under different treatments (%)

[0076]

[0077] Table 4 Effects of different treatments on the appearance quality of baked tobacco leaves

[0078]

[0079] Table 5 Effects of different treatments on the grade structure of baked tobacco leaves (%)

[0080]

[0081] Table 6 Effects of different treatments on the contents of aroma components in baked tobacco leaves (μg / g)

[0082]

[0083] Table 7 Effects of different treatments on the chemical component contents and sensory quality of baked tobacco leaves

[0084]

[0085] Note: The sensory quality evaluation is the sum of the scores of 6 items including aroma quality, aroma quantity, taste, off-flavor, irritation, and body, and each item is 10 points.

[0086] It is not difficult to see from Tables 2 - 7 that the new technology baking method (the method described in the present invention) is superior to conventional baking (traditional three-stage baking) in terms of baking energy consumption cost, degradation amount of tobacco leaf starch and plastid pigments, appearance quality of tobacco leaves, grade structure of tobacco leaves, content of aroma components in tobacco leaves, chemical component content of tobacco leaves, and sensory quality, and the quality and quality of the baked tobacco leaves are significantly improved.

[0087] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. This specification selects and specifically describes the embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention.

Claims

1. A method for withering and softening tobacco leaves and baking them, characterized in that, It includes the following steps: S1. Harvesting of mature fresh tobacco leaves: harvesting fresh tobacco leaves by part according to the maturity standards; S2. Fresh tobacco leaf classification and sorting: Based on the maturity and texture characteristics of fresh tobacco leaves, make a preliminary judgment on the quality and baking characteristics of the tobacco leaves; S3, light quality stress and wilting of fresh tobacco leaves: the unripe, physiologically mature and technologically mature fresh tobacco leaves are subjected to light quality stress and wilting, while the mature and over-ripe fresh tobacco leaves are relatively severely aged and are not subjected to light quality stress; the light quality stress and wilting is to irradiate the fresh tobacco leaves on the tobacco drying rack with three light qualities: blue light, yellow light and purple light; S4. Classify and load fresh tobacco leaves into the oven: divide the loading room into high-temperature zone and low-temperature zone according to the airflow movement mode in the curing room. Over-ripe and fully-ripe tobacco leaves are loaded in the high-temperature zone, under-ripe and physiologically mature tobacco leaves are loaded in the low-temperature zone, and the remaining space in the loading room is loaded with process-mature tobacco leaves. S5. Fresh tobacco leaf baking: The three-stage baking process is adopted for baking. The baking process is divided into three stages. The first stage is the stage of withering, softening, yellowing and soft tendons, the second stage is the stage of drying, yellowing and soft tendons, and the third stage is the stage of drying tendons. The stage of withering, softening, yellowing and soft tendons includes the following steps: S5-1. Before ignition, the tobacco leaves placed in step S4 are circulated at a high wind speed of the circulating fan for 1 to 3 hours; after ignition, the circulating fan is activated at a low wind speed, and the temperature is raised to 32 to 33°C at a rate of 1°C per hour, and the wet bulb temperature is stabilized at 31 to 32°C. The temperature is kept constant for 3 to 5 hours until the tobacco leaves in the high temperature layer turn 1 to 2 degrees yellow; S5-2. Keep the circulating fan at a low wind speed, raise the temperature to 35-36℃ at a rate of 1℃ per hour, stabilize the wet bulb temperature at 34-35℃, and bake at a stable temperature for 3-5 hours until the tobacco leaves in the high temperature layer turn 20% to 30% yellow; S5-3. Maintain the circulating fan at a medium wind speed, raise the temperature to 38-39°C at a rate of 1°C per hour, stabilize the wet-bulb temperature at 36-37°C, and bake at a steady temperature for 15-25 hours until the tobacco leaves in the high-temperature layer turn 70% to 80% yellow, with the leaves withering and becoming soft; S5-4. Start the circulating fan at medium or high wind speed, raise the temperature to 40-41°C at a rate of 1°C every 2 hours, stabilize the wet bulb temperature at 36-37°C, and bake at a steady temperature for 10-15 hours until the high-temperature layer tobacco leaves turn 80% to 90% yellow and the main veins become soft; S5-5. Enable the circulating fan at high wind speed, raise the temperature to 43-44°C at a rate of 1°C every 3 hours, stabilize the wet-bulb temperature at 35-37°C, bake at a steady temperature for 10-15 hours, and control the moisture until the tobacco leaves in the high-temperature layer are fully withered and softened, and the leaves and hooks are curled at the yellowing tips.

2. The method for withering and softening tobacco leaves and baking according to claim 1, characterized in that: In step S1, the maturity characteristics of fresh tobacco leaves include the appearance color of the tobacco leaves, the shape and glossiness of the leaf surface, the fading of the main and branch veins, the shedding of glandular hairs, the uniformity of the base of the tobacco leaves, and the maturity spots of the tobacco leaves.

3. The method for withering and softening tobacco leaves and baking according to claim 2, characterized in that: In step S2, the texture characteristics of the fresh tobacco leaves include the secretion of glandular hairs on the leaf surface and oil content, softness, leaf thickness and moisture content.

4. The method for withering and softening tobacco leaves and baking according to claim 3, characterized in that: In step S3, blue light, yellow light, and purple light are irradiated for 4 to 5 hours each, and the three light qualities are irradiated alternately, and the light quality stress time is 12 to 15 hours in total, so that the tips and edges of the fresh tobacco leaves become soft, the leaves become slightly soft, and the water loss is 5% to 10%.

5. The method for withering and softening tobacco leaves and baking according to claim 4, characterized in that: In step S5, the dry slice yellow tendon stage includes the following steps: S6-1. After the tobacco leaves wither and become soft, keep the circulating fan at high speed, raise the temperature to 47~48℃ at a rate of 1℃ every 3 hours, stabilize the wet bulb temperature at 37~38℃, and bake at a steady temperature for 10~15 hours until more than 95% of the main tobacco leaves in the high temperature layer turn yellow, and the tobacco leaves are half dry and small rolls; S6-2. Maintain the circulating fan at a medium wind speed, raise the temperature to 50-51°C at a rate of 1°C every 2 hours, stabilize the wet-bulb temperature at 38-39°C, and bake at a steady temperature for 6-8 hours until the main ribs of the tobacco leaves are completely yellow and obviously shrunk, and the leaves are more than 2 / 3 dry; S6-3. Maintain the circulating fan at medium wind speed, raise the temperature to 53-54°C at a rate of 1°C every 2 hours, stabilize the wet-bulb temperature at 38-40°C, and bake at a steady temperature for 10-15 hours until the tobacco leaves are completely dry and rolled into large rolls, and the main tendons gradually change from yellow to purple-brown.

6. The method for withering and softening tobacco leaves and baking according to claim 5, characterized in that: In step S5, the dry tendon stage includes the following steps: S7-1. After the yellow rib stage of the dried tobacco leaves is completed, keep the circulating fan at a low wind speed, raise the temperature to 57-60℃ at a rate of 1℃ per hour, stabilize the wet bulb temperature at 39-40℃, and bake at a stable temperature for 6-10 hours until the main ribs of the high-temperature layer tobacco leaves are more than 2 / 3 dry; S7-2. Keep the circulating fan at a low wind speed and continue to raise the temperature to 64-68℃ at a rate of 1℃ per hour. Keep the wet-bulb temperature stable at 39-40℃. Bake at a steady temperature for 15-20 hours until the main tendons of the tobacco leaves are completely dry.

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