Method for extracting tobacco flavor from waste tobacco leaves

Abstract

The invention discloses a method for extracting tobacco flavor from waste tobacco leaves, and belongs to the technical field of tobacco flavor. The method comprises the following steps: filling waste tobacco leaves serving as raw materials into a superheated steam distillation-dry distillation device; introducing mixed gas of nitrogen and superheated water vapor into the dry distillation kettle, starting the device, carrying out programmed heating, carrying out component extraction on the waste tobacco leaves, and collecting distillates; and extracting the distillate by using an organic solvent, dehydrating the extract, and carrying out rotary evaporation to recover the solvent, thereby obtaining the tobacco flavor. According to the method, the tobacco flavor is extracted from the waste tobacco leaves, recycling of the waste tobacco leaves is achieved, the obtained product has rich roasted fragrance, scorch fragrance and sweet fragrance and is suitable for perfuming of novel tobacco products, and the yield of the tobacco flavor extracted from the waste tobacco leaves reaches up to 10.76%. According to the method, high-efficiency and high-quality extraction and utilization of the waste tobacco are realized, and the method 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 waste 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 awareness of personal health protection among the public, new tobacco products are developing rapidly as an important substitute for traditional tobacco. For example, heated cigarettes are new tobacco products that use special heat sources to heat below 350°C without causing tobacco combustion. They greatly reduce the release of harmful substances and have 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 unburned tobacco is much lower than that of traditional tobacco, and it cannot release enough aroma-causing substances, resulting in weak tobacco aroma and lack of characteristic aromas such as roasted aroma, caramel aroma, and sweet aroma. Therefore, external spices are needed to enhance the aroma and strength. However, the tobacco spices extracted by conventional methods cannot meet its requirements.

[0003] Tobacco flavors are usually extracted by steam distillation, solvent extraction and other methods. The steam distillation method is usually used to extract tobacco flavors, and the yield is usually around 0.1%, extracting free aromatic components such as solanone, palmitic acid, damasconone, and neophytadiene; the solvent method is used to extract tobacco flavors, and the yield is about 1-2%, which can extract free aromatic components such as solanone, megastigmatrienone, and neophytadiene. Both methods have low extraction yields and lack the characteristic aromas required by tobacco, such as roasted aroma, caramel aroma, and baked aroma. In particular, the tobacco leaves after the free aromatic components are extracted become waste tobacco leaves and lose their utilization value.

[0004] In addition to a small amount of free aromatic components, tobacco leaves also contain a large amount of flavor precursors such as cellulose, hemicellulose, lignin, protein, pectin, etc., and the discarded tobacco leaves after extraction basically retain these flavor precursors. These substances will undergo pyrolysis and corresponding chemical reactions under conditions such as high temperature and suitable media, such as the Maillard reaction, to produce aromatic substances such as aldehydes, ketones, aromatic rings, furans, and heterocyclics. The number of aromatic components produced by these precursors is much higher than the free aromatic components contained in the original tobacco, and can provide characteristic aromas such as roasted aroma, caramel aroma, and baking aroma, improving 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 solution adopted by the present invention is 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 by program, extracting components from the waste tobacco leaves, and collecting distillates; extracting the distillates by using an organic solvent, dehydrating the extract, and recovering the solvent by rotary evaporation to obtain tobacco flavors; wherein the waste tobacco leaves are fresh tobacco leaves obtained by 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.

[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 retort 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 second, third and fourth ratios 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 the waste tobacco raw materials with the superheated steam distillation-drying integrated technology, and the amount of water vapor required for the extraction process is less, the collection time is shorter, and the collection temperature is lower, 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 flavors from waste tobacco leaves at a yield of more than 10%, which is similar to the yield of unextracted tobacco raw materials and much higher than the yield of other methods of extracting original tobacco raw materials, and the aroma style and smoking quality can achieve the effect of enhancing roasted aroma, mellowness and smoke;

[0019] 3) The method of the present invention is particularly suitable for the processing of tobacco flavors with roasted aroma, caramel aroma, baked aroma and the like, can be widely used in the preparation of new products, and realizes the efficient 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. In the following examples, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art. If no specific conditions are 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 absolute dry raw material.

[0022] Example 1

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

[0024] (1) Weighing 100 g of sun-dried tobacco leaf fragments into a three-necked flask, adding 500 mL of distilled water, and performing steam distillation at 100° C. for 6 h. During the distillation process, magnetic stirring is performed, 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 sun-dried tobacco leaf fragments after extraction 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; extracting the essential oil stored in the water separator with ether for 4 times, the volume ratio of the first extraction solvent to the distillate is 1:1, and the ratios of the second, third, and fourth extractions are 1:4, adding anhydrous sodium sulfate to the extract, stirring and dehydrating, and recovering the solvent using 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 (air-dried tobacco leaf fragments after steam distillation prepared in step (1)), with a filling rate of 30%-40% of the volume of the superheated water steam distillation-dry distillation device; heating the dry distillation kettle by electric heating of the outer wall, with a heating 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 the heating rate in the dry distillation kettle being 3° C. / min; the mixed gas containing the extract is condensed 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 flavor from discarded tobacco leaves comprises the following steps:

[0029] (1) Weigh 100 g of sun-dried tobacco leaf fragments into a three-necked flask, add 500 mL of petroleum ether, heat in an oil bath, and reflux the petroleum ether for 6 hours; filter and distill under reduced pressure to recover the solvent, and finally obtain tobacco essential oil and sun-dried tobacco leaf fragments after extraction. Wash the sun-dried tobacco leaf fragments after extraction with petroleum ether, and dry them in the sun for 48 hours to obtain sun-dried tobacco leaf fragments after petroleum ether extraction.

[0030] (2) preheating the dry distillation equipment 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 device; heating the dry distillation kettle by electric heating of the outer wall, with a heating 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 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 the heating rate in the dry distillation kettle being 3° C. / min; the mixed gas containing the extract is condensed when passing through a condenser tube through which circulating cooling water is passed, and collecting a distillate at 200-350° C.;

[0031] (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.

[0032] Comparative Example 1

[0033] (1) preheating the dry distillation equipment 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 device; 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 by means of superheated water vapor and electrical heating of the outer wall, with a heating rate of 3° C. / min in the dry distillation kettle; 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 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 yield results 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 yield of different tobacco raw materials

[0037]

[0038]

[0039] As shown in Table 1, when the sun-dried tobacco raw materials and sun-dried tobacco waste were extracted by superheated steam distillation-retorting process, the flavor yield of tobacco waste was lower than that of tobacco raw materials, but this yield was higher than that of the flavor extraction by conventional extraction methods.

[0040] The amount of steam required by the tobacco waste extraction method of the present invention is half of the amount of steam required for extracting air-dried tobacco raw materials in Comparative Example 1, and the collection temperature section and collection time of the spices extracted from the tobacco waste are shorter than the collection temperature and collection time of the spices extracted from other tobacco leaves under the same method. Although the yield is slightly reduced, the energy consumption is reduced, meeting the social demand for energy conservation and emission reduction. The method of the present invention realizes the efficient and high-quality reuse of tobacco waste, and has good economic and social benefits.

[0041] Example 3

[0042] The tobacco flavor extracted by superheated steam distillation-drying technology in Examples 1-2 and the tobacco flavor 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 Main aromatic components content of tobacco flavor obtained in Examples 1-2 and Comparative Example 1

[0044]

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

[0046] Example 4

[0047] The tobacco flavors extracted by superheated steam distillation-drying technology in Example 1-2 and the tobacco flavors obtained in Comparative Example 1 were subjected to an aroma sensory evaluation, wherein the blank sample was a commercially available cigarette, the source of which was the original flavor heated cigarette commercially available from Shanghai New Tobacco Products Research Institute Co., Ltd.; the preparation process of the unextracted sample was as follows: the sample prepared in Comparative Example 1 was diluted to 1% with 95% ethanol, and added to the heated cigarette at 10% of the weight of the cigarette sheet. The aroma sensory evaluation includes five indicators: fragrance, smoke, strength, irritation, and aftertaste. Each indicator was scored according to the scoring principle of 1-9 points for strength, height, and size. The aroma sensory evaluation of the obtained tobacco flavors is shown in Table 3.

[0048] Table 3 Heated cigarette smoking results

[0049] Tobacco leaf source fragrance Smoke Momentum Irritant 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 waste tobacco leaf extract spices 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 which the waste tobacco leaves after steam distillation had the highest score and were very close to the score of 36.0 of the unextracted tobacco leaves. This shows that the improvement of the smoking quality of heated cigarettes by tobacco spices mainly comes from the pyrolysis of the spice precursors and the aroma components produced by a series of chemical reactions, and has nothing to do with the free aromatic components originally contained. It is precisely because the spice precursors of the waste tobacco leaves after steam distillation are basically intact, and a large number of aroma components are produced through pyrolysis and corresponding chemical reactions, so the improvement of the smoking quality of heated cigarettes is more obvious than 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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for extracting tobacco flavor from waste tobacco leaves, characterized in that: The waste tobacco leaves are used as raw materials and loaded 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 raised programmatically, components of the waste tobacco leaves are extracted, and distillates are collected; the distillates are extracted with an organic solvent, the extract is dehydrated, and the solvent is recovered by rotary evaporation to obtain tobacco flavors; wherein the waste tobacco leaves are obtained by steam distillation or solvent extraction of fresh tobacco leaves.

2. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: The fresh tobacco leaves are selected from any one of flue-cured tobacco, air-cured tobacco, aromatic tobacco, burley tobacco and cigar tobacco.

3. The method for extracting tobacco flavor from waste tobacco leaves according to claim 2, characterized in that: The fresh tobacco leaves are sun-dried tobacco.

4. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: The filling rate of the waste tobacco leaves is 30-90% of the volume of the superheated water vapor distillation-carbon distillation device.

5. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: The programmed temperature rise process of the superheated steam distillation-carbon distillation device is: the temperature is raised from the preheating temperature to 180°C at a heating rate of 10°C / min, and then the temperature is raised to 350°C at a heating rate of 3°C / min.

6. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: The nitrogen flow rate in the dry distillation kettle is 100 mL / min, and the superheated water vapor flow rate is 400 g / h.

7. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: Collect the distillate at 200-350°C.

8. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: The solvent used for the extraction is a mixed solvent of ethyl acetate and n-hexane in a volume ratio of 1:

1. The extraction step is performed four 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.

9. The method for extracting tobacco flavor from waste tobacco leaves according to claim 1, characterized in that: The solvent extraction is performed using petroleum ether.

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