A method for extracting tobacco flavor from waste tobacco leaves

Abstract

The present invention discloses a method for extracting tobacco flavoring from discarded tobacco leaves, and belongs to the technical field of tobacco flavoring. The present invention uses discarded tobacco leaves as raw materials and loads them into a superheated steam distillation-drying device; a mixed gas of nitrogen and superheated steam is introduced into the dry distillation kettle, the device is started, the temperature is programmed, the components of the discarded tobacco leaves are extracted, and the distillate is collected; the distillate is extracted using an organic solvent, the extract is dehydrated, and the solvent is recovered by rotary evaporation to obtain tobacco flavoring. The present invention extracts tobacco flavoring from discarded tobacco leaves and realizes the reuse of discarded tobacco leaves, and the obtained product has a rich roasted aroma, burnt aroma, and sweet aroma, which is suitable for flavoring new tobacco products, and the yield of tobacco flavoring extracted from discarded tobacco leaves is as high as 10.76%. The present invention realizes the efficient and high-quality extraction and utilization of discarded tobacco, and has good industrial application prospects and economic and social benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of tobacco flavorings, and more specifically relates to a method for extracting tobacco flavorings from discarded tobacco leaves. Background Art

[0002] China is the world's largest tobacco producer and consumer. However, with the continuous development of society and the increasing public awareness of personal health protection, new tobacco products have rapidly developed as an important alternative to traditional tobacco. For example, heated cigarettes are new tobacco products that use a special heat source to heat the tobacco below 350°C without causing it to burn. They greatly reduce the release of harmful substances while having a characteristic feel similar to that of tobacco. Compared with the combustion temperature range of 300-850°C for traditional cigarettes, the temperature of heated cigarettes is lower, and the degree of pyrolysis of the unburned tobacco is far lower than that of traditional tobacco, which cannot release enough flavoring substances. As a result, the tobacco aroma is weak and lacks characteristic aromas such as roasted aroma, caramel aroma, and sweet cream aroma. Therefore, external flavorings are needed to enhance the aroma and strength. However, the tobacco flavorings extracted by conventional methods cannot meet these requirements.

[0003] Tobacco flavoring is typically extracted using methods such as steam distillation and solvent extraction. Steam distillation typically yields around 0.1% of tobacco flavoring, extracting free aromatic components such as solanone, palmitic acid, damascone, and neophytadiene. Solvent extraction yields approximately 1-2% of tobacco flavoring, extracting free aromatic components such as solanone, megastigmatrienone, and neophytadiene. Both methods yield relatively low yields and lack the characteristic aromas of tobacco, such as roasted, caramel, and baked flavors. In particular, after the free aromatic components have been extracted, the tobacco leaves become waste and lose their value.

[0004] In addition to small amounts of free aromatic components, tobacco leaves also contain significant quantities of flavor precursors, such as cellulose, hemicellulose, lignin, protein, and pectin. These flavor precursors are virtually completely retained in the discarded tobacco leaves after extraction. Under high temperatures and suitable media, these substances undergo pyrolysis and subsequent chemical reactions, such as the Maillard reaction, to produce aromatic compounds such as aldehydes, ketones, aromatic rings, furans, and heterocyclic rings. The amount of aromatic compounds produced by these precursors far exceeds the free aromatic components present in the original tobacco, and they contribute to the characteristic aromas of smoked, burnt, and roasted tobacco, enhancing the smoking quality. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for extracting tobacco flavors from discarded tobacco leaves, which can effectively realize the reuse of discarded tobacco leaves.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] A method for extracting tobacco flavor from waste tobacco leaves comprises the following steps: using waste tobacco leaves as raw materials and loading them into a superheated steam distillation-drying device; introducing a mixed gas of nitrogen and superheated steam into a dry distillation kettle, starting the device, raising the temperature through a program, extracting components from the waste tobacco leaves, and collecting distillates; extracting the distillates using an organic solvent, dehydrating the extract, and recovering the solvent through rotary evaporation to obtain tobacco flavors; wherein the waste tobacco leaves are fresh tobacco leaves obtained through steam distillation or solvent extraction.

[0008] Preferably, the fresh tobacco leaves are selected from any one of flue-cured tobacco, air-cured tobacco, oriental tobacco, burley tobacco and cigar tobacco.

[0009] Preferably, the fresh tobacco leaves are sun-dried tobacco leaves.

[0010] Preferably, the filling rate of the waste tobacco leaves is 30 to 90% of the volume of the superheated steam distillation-carbon distillation device.

[0011] Preferably, the programmed temperature rising process of the superheated steam distillation-carbon distillation device is: heating from the preheating temperature to 180°C at a heating rate of 10°C / min, and then heating to 350°C at a heating rate of 3°C / min.

[0012] Preferably, the nitrogen flow rate in the dry distillation kettle is 100 mL / min, and the superheated water vapor flow rate is 400 g / h.

[0013] Preferably, the distillate at 200-350°C is collected.

[0014] Preferably, the solvent used for the extraction is a mixed solvent of ethyl acetate and n-hexane in a volume ratio of 1:1, and the extraction step is performed four times, with the volume ratio of the first extraction solvent to the distillate being 1:1, and the ratios for the second, third and fourth times being 1:4.

[0015] Preferably, the solvent extraction is performed using petroleum ether.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The present invention creatively combines waste tobacco leaf raw materials with superheated steam distillation-drying integrated technology. The extraction process requires less steam, shorter collection time, and lower collection temperature, meeting the needs of improving efficiency, reducing energy consumption, and saving energy and reducing emissions.

[0018] 2) The method of the present invention can extract tobacco flavor from waste tobacco leaves at a yield of over 10%, which is similar to the yield of unextracted tobacco raw materials and much higher than the yield of other methods for extracting raw tobacco raw materials. The aroma style and smoking quality can achieve the effect of enhancing the roasted aroma, mellowness and smoke.

[0019] 3) The method of the present invention is particularly suitable for the processing of tobacco flavorings with characteristics such as roasted aroma, caramel aroma, and baked aroma, can be widely used in the preparation of new products, and realizes the high-efficiency and high-quality recycling of tobacco waste, with good economic and social benefits. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with specific examples. Unless otherwise specified in the following examples, the technical means used are conventional means well known to those skilled in the art. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer.

[0021] In the following examples, tobacco flavor yield (%) = mass of tobacco flavor / mass of tobacco raw material × 100%, wherein the mass of tobacco raw material refers to the mass of the absolutely dry raw material.

[0022] Example 1

[0023] A method for extracting tobacco flavoring from discarded tobacco leaves comprises the following steps:

[0024] (1) Weigh 100 g of sun-dried tobacco leaf fragments and put them into a three-necked flask, and add 500 mL of distilled water, and perform steam distillation at 100 ° C for 6 h. During the distillation process, magnetic stirring is applied, and the distilled essential oil is taken out with the water vapor, refluxed through a condenser, and stored in a water separator; after the distillation is completed, the extracted sun-dried tobacco leaf fragments are washed with distilled water, and air-dried in the sun for 48 h to obtain the sun-dried tobacco leaf fragments after steam distillation; the essential oil stored in the water separator is extracted with ether for 4 times, the volume ratio of the first extraction solvent to the distillate is 1:1, and the ratios for the second, third, and fourth extractions are 1:4. Anhydrous sodium sulfate is added to the extract, and the extract is stirred for dehydration. The solvent is recovered by a rotary evaporator to obtain tobacco essential oil.

[0025] (2) preheating the dry distillation equipment to 100° C., adding 400 g of waste tobacco leaves (steam distilled air-dried tobacco leaf fragments prepared in step (1)), with a filling rate of 30%-40% of the volume of the superheated water steam distillation-dry distillation device; electrically heating the outer wall, heating the dry distillation kettle at a rate of 10° C. / min; after the temperature in the dry distillation kettle reaches 180° C., introducing a mixed gas of nitrogen and superheated water steam, with the flow rates of nitrogen and superheated water steam in the dry distillation kettle being 100 mL / min and 400 g / h, respectively, and heating the dry distillation kettle at a rate of 3° C. / min; condensing the mixed gas containing the extract when passing through a condenser tube through which circulating cooling water is passed, and collecting a distillate at 200-350° C.;

[0026] (3) extracting the distillate four times with a mixed solvent of ethyl acetate and n-hexane in a volume ratio of 1:1, wherein the volume ratio of the first extraction solvent to the distillate is 1:1, and the second, third, and fourth extraction ratios are 1:4, adding anhydrous sodium sulfate to the extract, stirring and dehydrating, and recovering the solvent using a rotary evaporator at 45° C. to obtain tobacco flavor.

[0027] Example 2

[0028] A method for extracting tobacco flavoring from discarded tobacco leaves comprises the following steps:

[0029] (1) Weigh 100 g of sun-cured tobacco leaf fragments into a three-necked flask, add 500 mL of petroleum ether, and heat in an oil bath. The petroleum ether is continuously refluxed for 6 h. Filter and vacuum distill to recover the solvent, and finally obtain tobacco essential oil and extracted sun-cured tobacco leaf fragments. Wash the extracted sun-cured tobacco leaf fragments with petroleum ether and dry them in the sun for 48 h to obtain sun-cured tobacco leaf fragments extracted with petroleum ether.

[0030] (2) preheating the dry distillation apparatus to 100° C., adding 400 g of waste tobacco leaves (the air-dried tobacco leaf fragments extracted with petroleum ether prepared in step (1)), with a filling rate of 30%-40% of the volume of the superheated water vapor distillation-dry distillation apparatus; electrically heating the outer wall, heating the interior of the dry distillation kettle at a rate of 10° C. / min; after the interior temperature of the dry distillation kettle reaches 180° C., introducing a mixed gas of nitrogen and superheated water vapor, with the flow rates of nitrogen and superheated water vapor in the dry distillation kettle being 100 mL / min and 400 g / h, respectively, and heating the interior of the dry distillation kettle at a rate of 3° C. / min; condensing the mixed gas containing the extract when passing through a condenser tube through which circulating cooling water is passed, and collecting a distillate at a temperature of 200-350° C.;

[0031] (3) extracting the distillate four times with a 1:1 volume ratio of ethyl acetate and n-hexane mixed solvent, wherein the volume ratio of the first extraction solvent to the distillate is 1:1, and the ratios for the second, third, and fourth extractions are 1:4. Anhydrous sodium sulfate is added to the extract, stirred for dehydration, and the solvent is recovered using a rotary evaporator at 45° C. to obtain tobacco flavor.

[0032] Comparative Example 1

[0033] (1) Preheating the dry distillation apparatus to 80° C., adding 400 g of air-dried tobacco leaf fragments, with a filling rate of 30%-40% of the volume of the superheated water vapor distillation-dry distillation apparatus; introducing a mixed gas of nitrogen and superheated water vapor into the dry distillation kettle, with the flow rates of nitrogen and superheated water vapor in the dry distillation kettle being 100 mL / min and 800 g / h, respectively; heating the dry distillation kettle at a temperature of 3° C. / min by means of superheated water vapor and electrical heating of the outer wall; condensing the mixed gas containing the extract when passing through a condenser tube through which circulating cooling water is passed, and collecting a distillate at a temperature of 150-350° C.;

[0034] (2) extracting the distillate four times with a mixed solvent of ethyl acetate and n-hexane in a volume ratio of 1:1, wherein the volume ratio of the first extraction solvent to the distillate is 1:1, and the second, third, and fourth extraction ratios are 1:4, adding anhydrous sodium sulfate to the extract, stirring and dehydrating, and recovering the solvent using a rotary evaporator at 45° C. to obtain tobacco flavor.

[0035] The yields of tobacco flavor obtained by the methods of Examples 1-2 and Comparative Example 1 are shown in Table 1 below.

[0036] Table 1 Extraction yields of different tobacco raw materials

[0037]

[0038]

[0039] As shown in Table 1, when the superheated steam distillation-carbon distillation process was used to extract sun-dried tobacco raw materials and sun-dried tobacco waste, the spice yield of tobacco waste was lower than that of tobacco raw materials, but this yield was higher than the spice extraction yield of conventional extraction methods.

[0040] The method for extracting tobacco waste from the present invention requires half the amount of steam required for extracting sun-cured tobacco raw material in Comparative Example 1. Furthermore, the temperature range and time for collecting flavors extracted from tobacco waste are shorter than those for extracting flavors from other tobacco leaves using the same method. Although the yield is slightly reduced, energy consumption is reduced, meeting the social needs of energy conservation and emission reduction. The method of the present invention achieves efficient and high-quality recycling of tobacco waste, resulting in significant economic and social benefits.

[0041] Example 3

[0042] The tobacco flavors extracted by superheated steam distillation-drying technology in Examples 1-2 and the tobacco flavors obtained in Comparative Example 1 were analyzed for aromatic components using gas chromatography-mass spectrometry. The results are shown in Table 2.

[0043] Table 2 Contents of main aromatic components of tobacco flavors obtained in Examples 1-2 and Comparative Example 1

[0044]

[0045] As shown in Table 2, the main aromatic components of tobacco flavors extracted from three different raw materials using the superheated steam distillation-drying process are basically the same. In addition, the tobacco flavor extracted from the sun-dried tobacco waste after steam distillation and petroleum ether extraction contains higher contents of nicotine (38.21%, 32.72%), furfuryl alcohol (1.59%, 2.02%), and guaiacol (6.52%, 5.07%) than the tobacco flavor extracted from the sun-dried tobacco raw materials, while the contents of nitrogen heterocyclic compounds and neophytadiene are almost the same. Therefore, the quality of tobacco flavor extracted from waste tobacco by the present invention is not reduced under the conditions of reducing the steam volume, shortening the collection time and temperature range, achieving efficient and high-quality recycling of tobacco waste, reducing energy consumption, and having good economic and social benefits.

[0046] Example 4

[0047] Aroma sensory evaluations were conducted on the tobacco flavorings extracted using superheated steam distillation and dry distillation techniques in Examples 1-2 and the tobacco flavoring obtained in Comparative Example 1. The blank samples were commercially available original heated cigarettes from Shanghai New Tobacco Products Research Institute Co., Ltd. The unextracted samples were prepared by diluting the sample prepared in Comparative Example 1 to 1% with 95% ethanol and adding 10% of the weight of the tobacco sheets to the heated cigarettes. The aroma sensory evaluation included five indicators: aroma, smoke, punch, pungency, and aftertaste. Each indicator was scored on a scale of 1 to 9 for strength, height, and size. The aroma sensory evaluations of the tobacco flavors are shown in Table 3.

[0048] Table 3 Heated cigarette smoking results

[0049] Tobacco leaf source fragrance flue gas Momentum Irritation Aftertaste Total score Blank 6.0 6.0 6.0 6.0 6.0 30.0 Example 1 7.0 7.5 6.8 7.1 7.0 35.4 Example 2 6.5 7.0 6.5 6.8 6.8 33.6 Comparative Example 1 7.2 7.0 7.0 7.5 7.3 36.0

[0050] As can be seen from Table 3, the application of the flavoring extracted from waste tobacco leaves prepared by the present invention to heated cigarettes significantly improves the aroma, smoke, strength, irritation and aftertaste, thereby improving the smoking quality of heated cigarettes. The total scores of waste tobacco leaves after steam distillation and petroleum ether extraction were 35.4 and 33.6, respectively. Among them, the score of waste tobacco leaves extracted by steam distillation was the highest and was very close to the score of 36.0 of unextracted tobacco leaves. This shows that the improvement of the smoking quality of heated cigarettes by tobacco flavoring mainly comes from the pyrolysis of flavor precursors and the aroma components produced by a series of chemical reactions, and has nothing to do with the original free aromatic components. It is precisely because the flavor precursors of waste tobacco leaves after steam distillation are basically intact, and a large number of aroma components are produced through pyrolysis and corresponding chemical reactions, that the improvement in the smoking quality of heated cigarettes is more obvious than that of solvent extraction.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for extracting tobacco flavor from waste tobacco leaves, characterized in that: Waste tobacco leaves are used as raw materials and loaded into a superheated water vapor distillation-drying device, with the loading rate of the waste tobacco leaves being 30-90% of the volume of the superheated water vapor distillation-drying device; a nitrogen and superheated water vapor mixture is introduced into the dry distillation kettle, the device is started, and the temperature is increased from a preheating temperature to 180°C at a heating rate of 10°C / min, and then to 350°C at a heating rate of 3°C / min, the nitrogen flow rate in the dry distillation kettle is 100 mL / min, and the superheated water vapor flow rate is 400 g / h, the waste tobacco leaves are subjected to component extraction, and distillates at 200-350°C are collected; the distillates are extracted four times using a mixed solvent of ethyl acetate and n-hexane in a volume ratio of 1:1, with the volume ratio of the first extraction solvent to the distillate being 1:1, and the ratios of the second, third, and fourth extractions being 1:4, the extracts are dehydrated, and the solvent is recovered by rotary evaporation to obtain tobacco flavorings; wherein the waste tobacco leaves are obtained by steam distillation of sun-dried tobacco or extraction with petroleum ether; The air-cured tobacco is selected from any one of flue-cured tobacco, air-cured tobacco, oriental tobacco, burley tobacco, and cigar tobacco; The main aromatic components of the obtained tobacco flavor include furfural, nicotine and guaiacol.

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