CN113349413B

CN113349413B - Preparation method of low-temperature fraction capable of enhancing aroma and reducing harm for heating cigarettes and application of low-temperature fraction in heating cigarettes

Info

Publication number: CN113349413B
Application number: CN202110790218.1A
Authority: CN
Inventors: 杨继; 向能军; 夭建华; 朱瑞芝; 唐石云; 夏建军; 司晓喜; 李振杰; 何沛; 张凤梅; 蒋薇
Original assignee: China Tobacco Yunnan Industrial Co Ltd
Current assignee: China Tobacco Yunnan Industrial Co Ltd
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2022-08-02
Anticipated expiration: 2041-07-13
Also published as: CN113349413A

Abstract

The invention belongs to the technical field of heating cigarettes, and particularly relates to preparation of low-temperature fractions capable of enhancing aroma and reducing harm applied to heating cigarettes and application of the low-temperature fractions in heating cigarettes. The preparation method comprises the following steps: carrying out reflux extraction on a mixed raw material of Turkey aromatic tobacco leaves and guava leaves by using ethyl acetate, wherein the using amount of the ethyl acetate is 10-30 times of the mass of the raw material, the extraction time is 1-3 hours, and the extraction frequency is 2-5 times, so as to obtain a primary extract; fully dissolving the primary extract by using 2-5 mass times of ethyl acetate at the temperature of 65-75 ℃, uniformly stirring, freezing at-5-15 ℃ for 10-18 h, and performing suction filtration to obtain a filtrate; the acidic components extracted from the filtrate are low-temperature fractions. The low-temperature distillate with the functions of increasing aroma and reducing harm is obtained by reflux extraction and acid-base separation from natural raw materials, is applied to heating cigarettes, can round aroma, modify aroma, improve smoking taste, endow products with characteristic aroma style, and can effectively reduce harmful ingredients such as polycyclic aromatic hydrocarbon, free radicals and the like in smoke of the heating cigarettes.

Description

Preparation method of low-temperature fraction capable of enhancing aroma and reducing harm for heating cigarettes and application of low-temperature fraction in heating cigarettes

Technical Field

The invention belongs to the technical field of heating cigarettes, and particularly relates to a preparation method of low-temperature fractions capable of enhancing aroma and reducing harm for heating cigarettes and application of the low-temperature fractions in heating cigarettes.

Background

More than 6000 chemical compositions identified in the traditional cigarette smoke are reported in the literature, the chemical compositions are mainly generated by related components in tobacco through direct transfer or pyrolysis and thermal synthesis reactions, and part of harmful components can be decomposed or combined under the condition of high temperature (combustion), so that the following can be known: the emission of harmful components in the smoke can be obviously reduced by reducing the heating or combustion temperature. In addition, sidestream smoke generated after the traditional cigarette is ignited (mainly smoke escaping from the smoldering cigarette ignition end in the smoking interval period) can cause non-people to passively smoke, and the unpleasant feeling of the non-smoking people is caused.

Smokers desire to smoke cigarettes with lower harm, non-smoking people want to avoid the harm of passive smoking, and the reasons boost the generation of novel herbal products. Currently, the new types of tobacco products appearing on the market include: heating cigarettes, smokeless tobacco products, and electronic cigarettes.

The heating of non-burning tobacco product (also known as cigarette) is a new type of tobacco product which is produced by heating tobacco material with special heating source, and the nicotine and flavor substance in the tobacco material are volatilized to produce smoke to meet the requirements of smokers. Different from the traditional cigarette, the cigarette is heated without being ignited, so that the harmful components generated by high-temperature combustion and cracking of tobacco are reduced as much as possible. But the tobacco substances are not ignited, a large amount of flavor components generated by thermal synthesis and thermal cracking are reduced, and the problems of poor oral comfort, bitter feeling, insufficient aroma and the like are inevitably generated in the process of heating cigarettes for smoking.

At present, the flavor is mainly added into the heated cigarette to enrich the taste of the smoke. The tobacco part of the heated cigarette is always in a heated state (about 200-350 ℃) in the smoking process, and the additional essence and flavor are easy to volatilize and completely disappear in the first mouth and the second mouth, so that the problems of uneven taste, unstable quality and the like are caused. The taste accompanied with strong flavor and chemical smell during smoking has certain gap with the smoking quality of cigarettes. And some flavors and fragrances added in the traditional cigarette, such as macromolecular organic substances, such as raspberry ketone, thymol and dihydrocoumarin, have boiling points of more than 200 ℃, and can generate fragrance components similar to flowery scent, fruity fragrance and bean fragrance only after high temperature, and can not be completely volatilized in a heating temperature range of the heated cigarette and can not bring expected effects, so that the flavors and fragrances can not be completely transplanted into the heated cigarette for application.

The tobacco extract is an important way for adjusting the smoking taste and enhancing the performance of novel tobacco products. At present, tobacco extracts are widely applied to traditional cigarettes, but due to the difference of raw materials and the limitations of extraction processes, analysis means and use environments, most products are difficult to directly transplant into heated cigarettes to exert effects, and meanwhile, different extraction and separation means can damage heat-sensitive aroma substances to different degrees and cannot retain aroma components of the tobacco. The combination of extraction and separation processes is therefore the key to cryogenic fraction extraction.

Disclosure of Invention

In order to improve the smoking quality of the heated cigarette, the product is endowed with characteristic aroma style by mellow aroma, modifying aroma and improving smoking taste, and meanwhile, harmful ingredients such as polycyclic aromatic hydrocarbon, free radicals and the like in the smoke of the heated cigarette can be effectively reduced. The invention extracts and separates low-temperature new latent aroma substances from natural raw materials, and adds the substances into a formula of tobacco shreds of heated cigarettes to achieve the aims of increasing aroma and reducing harm.

In a first aspect, the present invention provides a process for the preparation of a fragranced, harm-reduced, low-temperature fraction, said process comprising the steps of:

carrying out reflux extraction on the mixed raw material of the aromatic tobacco leaves and the guava leaves of the Turkish by using ethyl acetate, wherein the using amount of the ethyl acetate is 10-30 times of the mass of the raw material, the extraction time is 1-3 hours, and the extraction times are 2-5 times to obtain a primary extract;

fully dissolving the primary extract by using 2-5 mass times of ethyl acetate at the temperature of 65-75 ℃, uniformly stirring, freezing at-5-15 ℃ for 10-18 h, and performing suction filtration to obtain a filtrate;

extracting the filtrate with 5-15 wt% of sodium carbonate solution, standing to separate out a water phase, neutralizing with acid until the pH value is 3-4, extracting with ethyl acetate, separating out an organic phase, drying with anhydrous sodium sulfate, filtering, concentrating the filtrate to obtain a brown yellow fluid, and dissolving back with anhydrous ethanol to obtain a low-temperature fraction.

Preferably, the mixed raw materials of the Turkish aromatic tobacco leaves and the guava leaves are crushed and sieved by a sieve with no less than 200 meshes.

Preferably, the mixed raw materials of the Turkish aromatic tobacco leaves and the guava leaves are as follows: the mass ratio of the Turkey aromatic tobacco leaves to the guava leaves is as follows: 10: 1-1: 1.

The second aspect of the invention provides the use of the low-temperature fraction described in the first aspect, wherein the low-temperature fraction is added into a heated cut tobacco formula of cigarettes in a flavoring and charging manner at a ratio of 1-5 wt% for smoking.

The low-temperature fraction is added into a formula of the heated cigarette cut tobacco, so that the aroma can be obviously rounded, the aroma can be modified, the smoking taste can be improved, the characteristic aroma style of the product can be endowed, and the harmful ingredients such as polycyclic aromatic hydrocarbon in smoke can be obviously reduced.

Compared with the prior art, the invention has the following beneficial effects:

1. the combination of raw material selection, extraction solvent selection and extraction method is the key, and the extracts obtained by different collocation combinations are different. The low-temperature fraction is obtained by using a specific Turkish aromatic tobacco leaf raw material and a guava leaf raw material and adopting a reflux extraction method and an acid-base separation method, and when the low-temperature fraction is applied to heating cigarettes, the low-temperature fraction can be used for rounding fragrance, modifying fragrance, improving smoking taste, endowing the products with characteristic fragrance style, and improving the smoking quality of the heating cigarettes. And the thermal weight loss experiment shows that the heated cigarette added with the low-temperature spice is largely pyrolyzed to generate volatile fragrant substances in the heating temperature range (compared with a blank sample). Thermal cracking experiments showed that the heated cigarette with the added heated low temperature flavor cracked much more flavor than the blank.

2. With the increasing attention of the public on smoking and health problems, the reduction of the release amount of harmful ingredients in cigarette smoke has important practical significance. The invention uses specific tobacco leaves and guava leaf raw materials, adopts a reflux extraction method and an acid-base separation method to prepare novel spice, and adds the novel spice into the heated cigarette, so that the harmful components of condensed ring aromatic hydrocarbons in the smoke of the heated cigarette can be selectively reduced, and the aim of reducing harm more obviously is fulfilled.

3. According to the invention, a specific Turkish aromatic tobacco leaf raw material, namely the guava leaf raw material, is used, a reflux extraction method and an acid-base separation method are adopted, so that a low-temperature fraction is obtained and added into the heated cigarette, and the problems that the flavor is not uniform and the quality is unstable due to the fact that the added flavor and aroma are easily volatilized out in the first mouth and the second mouth in the smoking process of the heated cigarette, and the flavor, aroma and chemical smell are accompanied during smoking and the like are solved. The aroma of the heated cigarette is stably and uniformly released in the smoking process, and a certain characteristic aroma style is given to the product, so that the cigarette is a novel high-stability novel spice.

4. The method directionally enriches the components of the aromatic tobacco leaves of the Turkish by a certain process means, thereby realizing the supplement and substitution of the tobacco leaves of a certain grade, a certain quality or a certain style, and playing an important role in relieving the contradiction of high-quality raw material requirements and improving the product quality.

5. The low-temperature latent aroma substances are extracted and separated from natural tobacco raw materials, the tobacco extract is derived from tobacco leaves, is not limited by a tobacco additive list, and the safety is also guaranteed.

Drawings

Figure 1 is a low temperature perfume total ion flow diagram obtained in example 1.

Fig. 2 is a Thermogravimetric (TG), Differential Thermal Gravimetries (DTG) -temperature (Temp) curve of a control of application example 3 pyrolyzed in an air atmosphere.

Fig. 3 is a Thermogravimetry (TG) and differential quotient thermogravimetry (DTG) -temperature (Temp) curve of a low-temperature fraction addition sample obtained in application example 3 pyrolyzed in an air atmosphere.

FIG. 4 is a thermal cracking chromatogram of a control sample of application example 4 at 350 ℃.

FIG. 5 is a thermal cracking chromatogram of a novel flavor additive sample obtained in application example 4 at 350 ℃.

Detailed Description

The present invention is further illustrated by the following examples, but is not limited to these examples. The experimental methods not specified in the examples are generally commercially available according to the conventional conditions and the conditions described in the manual, or according to the general-purpose equipment, materials, reagents and the like used under the conditions recommended by the manufacturer, unless otherwise specified. The starting materials required in the following examples and comparative examples are all commercially available.

Example 1

A process for the preparation of a flavored harm reduced low temperature fraction, said process comprising the steps of:

the Turkish aromatic tobacco is specifically the Itzmmel aromatic tobacco in the Itzmmel area.

Step 1, reflux extraction: performing reflux extraction on the mixed raw material of the aromatic tobacco leaves and the guava leaves of the Turkish by using ethyl acetate, wherein the using amount of the ethyl acetate is 20 times of the mass of the raw material, the extraction time is 2 hours, and the extraction times are 3 times to obtain a primary extract;

fully dissolving the primary extract by using 3 mass times of ethyl acetate at the temperature of 75 ℃, uniformly stirring, freezing at-10 ℃ for 12 hours, and performing suction filtration to obtain a filtrate;

step 2, acid-base separation: extracting the filtrate with 10 wt% sodium carbonate solution, standing to separate out a water phase, neutralizing with hydrochloric acid until the pH value is 3-4, extracting with ethyl acetate, separating out an organic phase, drying with anhydrous sodium sulfate, filtering, concentrating the filtrate to obtain a brown yellow fluid, dissolving the brown yellow fluid back with anhydrous ethanol, filtering, and concentrating the filtrate to obtain a fluid with the density of 0.945 +/-0.007, namely the low-temperature fraction.

Application example 1

First, physical and chemical index measurement

TSLF-03 was tested for appearance, clarity, relative density, miscibility (25 deg.C), acid number, total volatile content, etc., according to industry standard YC/T145.1-YC/T145.9. The heavy metal elements Pb and As in GB/T5009.74-2003 and GB/T5009.76-2003 are determined. XDS and HZS were determined in accordance with Q/HY.CJ.202-2009.

The specific results of the measurement of the physical and chemical indexes of the low-temperature fraction are shown in the table 1, and the detection results show that both products have better appearance quality and dissolution performance, and the contents of heavy metals Pb and As, XDS and HZS are also within the national food safety range.

TABLE 1 physicochemical indices of low-temperature fractions

Second, aroma component analysis

The aroma components in the extract are measured by GC-MS according to the tobacco industry standard. Refer to the determination of aroma components of tobacco and tobacco products and the simultaneous distillation extraction-gas chromatography-mass spectrometry combination TCJC-ZY-IV-014-2012.

GC-MS analysis test conditions: a chromatographic column: HP-5MS (60 m.times.0.132 mm.times.0.125 μm); carrier gas: he; flow rate: 1 mL/min; sample introduction temperature: 240 ℃; interface temperature: 250 ℃; mass spectrum scanning range: 35 to 455 amu; an ion source: EI source, electron energy: 70 eV. According to the analysis and test conditions, the volatile components are subjected to GC-MS analysis, and the mass fraction of each compound is determined as an area normalization method. The qualitative analysis of the compound is to confirm the chemical components in the mass spectrum information obtained by GC-MS combination through comparison and analysis of a Wiley and NISt 98 spectral library and a standard spectrogram by a computer.

The total ion flow diagram of volatile aroma components of the low-temperature fraction product is shown in a figure 1, and the specific analysis result is shown in a table 2.

TABLE 2 major volatile constituents of the low temperature distillate product

Through GC/MS analysis, 124 components are separated out altogether, 55 components (see the table above) with the matching degree of more than or equal to 80 are identified, the peak area accounts for 37.53 percent of the total peak area, and the chemical classes comprise acid compounds, ester compounds, ketone compounds, phenol compounds and alcohol compounds. The acid compounds with the highest content, 28, are respectively propionic acid (0.02%), 2-methylpropanoic acid (0.04%), butyric acid (0.01%), 3-methylbutyric acid (0.18%), 2-methylbutyric acid (0.24%), 3-methylpentanoic acid (0.88%), hexanoic acid (0.16%), 4-oxopentanoic acid (0.24%), heptanoic acid (0.13%), benzoic acid (0.73%), octanoic acid (0.19%), phenylacetic acid (0.94%), nonanoic acid (0.13%), salicylic acid (0.06%), decanoic acid (0.17%), 4-hydroxy-benzoic acid (0.36%), 4-hydroxyphenylacetic acid (0.46%), dodecanoic acid (0.10%), 3-hydroxy-4-methoxybenzoic acid (1.25%), nonanoic acid (0.34%), myristic acid (0.98%), 4-hydroxy-3, 5-dimethoxybenzoic acid (0.30%), (0.0.0.0.0.0%) and (0.30%), (S) -12-methyl-tetradecanoic acid (0.25%), pentadecanoic acid (0.59%), palmitic acid (18.10%), heptadecanoic acid (0.88%), (E) -9-octadecenoic acid (0.51%), stearic acid (0.95%) in 29.19% of the peak area of the main aroma components. Among these acid compounds, palmitic acid content was 48.23% of the acidic component, and was the main component in the nicotinic acid component of the ezzmur perfume. Among the identified acidic components, hexanoic acid, heptanoic acid, benzoic acid, phenylacetic acid, salicylic acid are commonly used tobacco flavor raw materials.

Application example 2

The low-temperature fraction obtained in example 1 was added to the cut tobacco formulation of cigarette heated in Yunnan according to a flavoring and charging manner by 2 wt% (low-temperature fraction mass/heated cigarette mass) to perform a smoke aerosol analysis test. The heated cigarette prepared by the same tobacco formula without adding guava leaves and acid-base separation treatment under the same process condition is used as a blank sample.

The aerosol inspection basis of the heated cigarette added with the low-temperature fraction and the blank sample is as follows:

GB/T23203.1-2013; GB/T19609-2004; GB/T23356-; GB/T21130-2007; GB/T23355-2009; YC/T253-2019; YC/T255-; YC/T254-; YC/T377-2019; Q/CTQ5-2010 (laboratory method for determination of tobacco-specific nitrosamines in total particulate matter of mainstream smoke). The results are shown in Table 3.

TABLE 3 comparison of the principal ingredients of the heated cigarette aerosols for the low temperature fraction and the blank

As can be seen from table 3, the low-temperature fraction obtained by extracting and separating specific tobacco leaves and guava leaves by reflux extraction and acid-base extraction can change the chemical components of the raw materials, and can be added into a heated cigarette for smoking to selectively reduce harmful components such as aldehydes, nitrogen oxides, polycyclic aromatic hydrocarbons, N-nitrosamines, phenols and the like in the smoke of the heated cigarette. Especially, the effect on reducing polycyclic aromatic hydrocarbon is obvious, benzene is reduced by 62%, and benzopyrene is reduced by 62%.

Application example 3 thermal analysis

The low-temperature fraction obtained in example 1 was diluted to 2 wt% and added to the cut tobacco formulation of cigarette heated in Yunnan China tobacco by adding flavoring and feeding to prepare the raw material, and the blank leaf group without any novel spice was used as a control.

Before sample analysis, a thermogravimetric analyzer is set to be kept for 10min at 800 ℃ so as to completely discharge impurities in the furnace body. The sensitivity of the thermobalance was 1. mu.g, with an empty crucible as reference. A typical heated cigarette tobacco material (5.00. + -. 0.05) mg was weighed into a hot platinum crucible. At the air flow rate of 80mL/min, the temperature rising programs are respectively as follows: 30 ℃ 10 ℃/min 800 ℃ (10 min).

FIG. 2 is a thermal analysis curve of a control sample at a temperature rise rate of 10 ℃/min and an air flow rate of 80 mL/min. As can be seen from the figure, the thermal weight loss is divided into four stages: firstly, the weight loss is 19.62 percent at the temperature of 50-237 ℃, which is a first weight loss stage; 243-352 ℃ weightlessness is 28.96 percent, which is the second weightlessness stage and has the most weightlessness; and 382 and 487 ℃ weight loss is 25.14 percent, which is a third weight loss stage. 568 and 734 ℃ weight loss of 4.74 percent are the fourth weight loss stage.

FIG. 3 is a thermal analysis curve of the low temperature flavor additive sample obtained in example 1 under the same conditions. As can be seen from fig. 3, the thermal weight loss is divided into five stages: firstly, the weight loss is 16.35 percent at the temperature of 28-78 ℃, which is a first weight loss stage; ② the second weight loss stage, weight loss 11.28% at 80-148 ℃. ③ 150 plus 292 ℃ weightlessness is 37.06 percent, which is the third weightlessness stage, the weightlessness is the most and more violent, a larger peak is also presented on the DTG curve, and the highest value is reached at 226.39 ℃; 293 and 360 ℃ weight loss of 20.42 percent, which is the fourth weight loss stage, the weight loss at the stage is most severe, and a large and sharp peak is formed in the figure. 470-500 deg.C weight loss 5.03%, as the fifth weight loss stage.

(1) The difference between the sample added with the low-temperature perfume and the control sample is that the thermal weight loss is increased from four stages to five stages, the thermal weight loss is larger from the second stage and the third stage to the third stage and the fourth stage, but the maximum weight loss temperature is obviously reduced.

(2) The control sample had a total weight loss of 54.1% from 243-487 ℃ in the main weight loss stage (two-and three-stage). After the sample added with the low-temperature spice, the first weight loss stage is obviously advanced, and is added with a weight loss stage compared with a reference sample, and the second weight loss stage (the weight loss is 11.28 percent at 80-148 ℃) indicates that some volatile small molecular substances are added and can be volatilized at a lower temperature. The main weight loss stages (three and four stages) are 150-360 ℃ weight loss of 57.48 percent, and firstly, the temperature moves to a lower range and almost falls within the working temperature range of heating the cigarette smoking set; and secondly, the pyrolysis substances are more, which shows that after the low-temperature spice is added, more substances are pyrolyzed and volatilized in the working temperature range of heating cigarettes, the smoke chemical substances are added, so that the smoke substances are fuller and richer, the aroma can be obviously rounded, the aroma can be modified, the smoking taste can be improved, the characteristic aroma style of the product is endowed, and the aroma enhancement effect is realized to the maximum extent.

The above sensory expression on aspiration is:

the control heated cigarette is extremely easy to volatilize a plurality of flavor substances before smoking in the smoking process, so that the taste is uneven and the quality is unstable. The sample added with the low-temperature spice has more flavor substances which are uniformly volatilized in the whole smoking process, and the uniformity and the stability of aroma release in the smoking process can be ensured.

Application example 4 thermal cracking study

(1) Preparation of samples and controls

The low-temperature spice obtained in example 1 is added into the cut tobacco formula of cigarette heated by Yunnan Zhongyan by a flavoring and feeding mode according to the proportion of 2 wt% to prepare a raw material, and meanwhile, a blank leaf group without any low-temperature spice is used as a control sample. The electric heating temperature for heating the cigarette is lower than 350 ℃, so the experiment is carried out in the temperature rise range of 50-350 ℃ for carrying out the research on the thermal cracking behavior.

(2) GC-MS conditions

Instrument GC/MS (HP6890N/5973N, Agilent, USA)

Chromatographic mass spectrum conditions: capillary column: HP-5MS (30m 0.25mm 0.25m), injection port temperature: 240 ℃, carrier gas: he, flow rate: 1mL/min, GC-MS interface temperature: temperature gradient at 250 ℃ is as follows: 50 ℃ (1min) -2 ℃/min-100 ℃ (1min) -8 ℃/min-260 ℃ (5min), ion source: EI source, electron energy: 70eV, scanning range: 35-455amu, standard atlas library: NIST, willey spectral library.

(3) Conditions of thermal cracking

The instrument comprises the following steps: PYROPROBE 2000(CDS, USA)

Conditions are as follows: initial temperature: temperature rise rate at 30 ℃: 20.00 ℃/ms, cracking temperature: 350 ℃, duration: 10s, cracking atmosphere: 10% oxygen, atmospheric air or nitrogen (gas flow: 2.5 ml/s).

(4) Solid phase micro-extraction conditions

When the incense raw materials and the additives are subjected to thermal cracking in an atmospheric environment, a black extraction head is adopted to extract a cracking product from a self-designed cracking bottle, the extraction time is 10min, the extraction temperature is 70 ℃, and then an SPME sample injection needle is inserted into a gas chromatography high-temperature vaporization chamber for desorption, wherein the desorption time is 2 min.

(5) Test method

Weighing a certain amount of sample (about 2mg) and adding the sample into a quartz tube special for cracking, then placing the quartz tube into a heating wire of a thermal cracking instrument, respectively carrying out thermal cracking at three set temperatures of 350 ℃ in different cracking atmospheres, placing a solid phase micro-extraction head into a self-designed cracking bottle to extract a cracking product, wherein the extraction time is 10min, the extraction temperature is 70 ℃, then inserting an SPME sample injection needle into a high-temperature vaporizing chamber of a gas chromatograph for desorption for 2min, and separating and identifying the cracking product in the gas chromatograph/mass spectrometer (GC/MS) to carry out standard library retrieval, wherein if the matching degree of the cracking product is not particularly specified to be more than 60.

The electric heating temperature for heating the cigarette is lower than 350 ℃, so the experiment is carried out in the temperature rise range of 50-350 ℃ for carrying out the research on the thermal cracking behavior. The comparison table of the thermal cracking components of the heated cigarette added with the low-temperature spice is shown in Table 4. Wherein 20 substances, mainly furfural (18.24%), 5-methyl-2-furfural (6.33%), nicotine (5.96%) and the like, are detected by contrast; the heated cigarette added with the low-temperature spice is detected to obtain 60 substances, wherein the substances mainly comprise nicotine (8.46%), furfural (8.04%), and 1, 2-propylene glycol (5.73%); therefore, the addition of the volatile micromolecule low-temperature fraction product can increase the richness of smoke of the heated cigarette, thereby improving the sensory quality of the heated cigarette.

TABLE 4 comparison of pyrolysis products after addition of the Low temperature distillate product to heated cigarettes (blank boxes are not checked)

Comparative example 3

Carrying out reflux extraction on the Iltzmel aromatic tobacco fragments by using ethyl acetate, wherein the using amount of the ethyl acetate is 20 times of the mass of the raw materials, the extraction time is 2 hours, and the extraction times are 3 times to obtain an initial extract;

fully dissolving the primary extract by using 3 times of ethyl acetate under the heating condition (the temperature is 65-75 ℃), uniformly stirring, freezing at-10 ℃ for 12 hours, and filtering. Extracting the filtrate with 10 wt% sodium carbonate solution, standing to separate out organic phase, washing with 10% sulfuric acid solution, and standing to separate out organic phase and water phase.

Wherein the organic phase is washed to neutrality with water and concentrated to obtain neutral component.

Wherein the aqueous phase is neutralized with base to pH 8-9, extracted with ethyl acetate, the organic phase is separated and concentrated to obtain the alkaline component.

The low-temperature fraction obtained in example 1 and the neutral component and the alkaline component obtained in the comparative example were applied to a heated cigarette for evaluation, and the evaluation standard was QYNZY.J07.604-2017 part 4 sensory specification of an electrically heated non-combustible cigarette, and the specific method was: the low-temperature fraction and the neutral component and the alkaline component obtained in this comparative example were first diluted to 5 wt% with solvent water, and then the diluted matter was added to a group of Yunnan medium-length tobacco-heated cigarette leaves in an aromatized manner at 0.25 wt% for testing.

The evaluation results are shown in the following table.

Components	Evaluation results
		Low temperature fraction obtained in example 1	Mellow fragrance, modifying fragrance, improving taste, and endowing the product with old fragrance and style
Neutral component	The smoke is soft and slightly irritant
		Basic component	Has obvious irritation

Sensory evaluation results show that the low-temperature distillation obtained in the example 1 has a good effect when applied to low-temperature cigarettes, and has mellow fragrance, modified fragrance, improved smoking taste and a stale fragrant and charming style. The neutral components have less outstanding effect, and the alkaline components increase the cigarette irritation.

Claims

1. A preparation method of low-temperature fraction capable of enhancing aroma and reducing harm for heating cigarettes is characterized by comprising the following steps:

carrying out reflux extraction on a mixed raw material of Turkey aromatic tobacco leaves and guava leaves by using ethyl acetate, wherein the using amount of the ethyl acetate is 10-30 times of the mass of the raw material, the extraction time is 1-3 hours, and the extraction frequency is 2-5 times, so as to obtain a primary extract;

extracting the filtrate with 5-15 wt% of sodium carbonate solution, standing to separate out a water phase, neutralizing with acid until the pH value is 3-4, extracting with ethyl acetate, separating out an organic phase, drying with anhydrous sodium sulfate, filtering, concentrating the filtrate to obtain a brown yellow fluid, and dissolving back with anhydrous ethanol to obtain a low-temperature fraction;

and adding the low-temperature fraction into a heated cigarette tobacco shred formula in a flavoring and feeding manner for smoking.

2. The preparation method according to claim 1, wherein the mixed raw material of the Turkish aromatic tobacco leaves and the guava leaves is sieved through a sieve of not less than 200 meshes after being crushed.

3. The preparation method according to claim 1, wherein the mass ratio of the Turkish aromatic tobacco leaves to the guava leaves is: 10: 1-1: 1.

4. The use of the low-temperature fraction obtained by the preparation method of claim 1, wherein the low-temperature fraction is added into a heated cut tobacco formula for smoking in a flavoring manner at a ratio of 1-5 wt%.

5. The use according to claim 4, wherein the low-temperature fraction is added into a heated cigarette cut tobacco formula, so that the aroma can be obviously rounded, the aroma can be modified, the smoking taste can be improved, the characteristic aroma and style of the product can be endowed, and the harmful components of the polycyclic aromatic hydrocarbon in the smoke can be obviously reduced.