Extraction method and analysis method of volatile flavor components in solid sample

Abstract

The invention belongs to the technical field of material test analysis methods, and particularly relates to an extraction method and an analysis method of volatile flavor components in a solid sample. The method for extracting the volatile flavor components in the solid sample comprises the following steps: mixing solid sample powder and fine quartz sand, putting the mixture into a distillation container in a solvent-assisted flavor evaporation device, covering the surface with coarse quartz sand, and filling a filter material at a hole opening, flowing to a collection container, of volatile gas in the distillation container, then, volatile flavor components are extracted through a solvent-assisted flavor evaporation technology, the mesh number of the fine quartz sand is 200 or above, and the mesh number of the coarse quartz sand is 60 or below. The solid sample powder is directly loaded into the distillation container for extraction, so that the loss of volatile aroma components caused in the solution extraction process is avoided, the original aroma components of the sample can be reserved to a greater extent, the aroma characteristics of the aroma raw materials are truly restored, and the extraction accuracy of the volatile aroma components in the solid sample is improved.

Description

Technical Field

[0001] The invention relates to the technical field of material testing and analysis methods, and in particular to an extraction method and an analysis method for volatile aroma components in a solid sample. Background Art

[0002] The extraction of volatile aroma components from natural animal and plant raw materials is of great significance in the fields of food, agriculture, medicine, flavors and fragrances. Different extraction methods determine the extraction effect of volatile components. At present, the preparative extraction methods of volatile aroma components of solid samples mainly include simultaneous distillation extraction, supercritical fluid extraction and solvent-assisted flavor evaporation.

[0003] Solvent-assisted flavor evaporation (SAFE) is a method for gently and comprehensively extracting volatile substances from complex matrices. It evaporates volatile components under high vacuum conditions without the need for high temperature conditions, which can effectively reduce the loss of heat-sensitive and volatile components in the sample. The flavor of the resulting extract is consistent with the sample, and the aroma is natural and realistic. At the same time, it can remove a large amount of non-volatile components in the sample, thereby obtaining highly concentrated flavor substances and reducing the matrix effect in subsequent instrumental analysis.

[0004] However, the current SAFE technology can only process liquid samples. If the sample contains a large amount of solid or semi-solid components with poor fluidity, it must be pretreated to convert the sample into a liquid sample through solvent extraction and other methods, and further extracted using SAFE technology. In October 2023, Mo Haoran et al. published the article "Headspace solid phase microextraction combined with solvent-assisted flavor evaporation to analyze the volatile components of seedless sea buckthorn and their contribution to aroma" using headspace solid phase microextraction and liquid-liquid extraction combined with solvent-assisted flavor evaporation (SAFE). In the SAFE extraction part, the sea buckthorn sample was pretreated by juicing and dichloromethane liquid-liquid extraction. In June 2024, Pu Dandan et al. disclosed in the article "Comparison of the Differences of Aroma Active Components of 18 Strong-Aroma Natural Spices by SAFE-GC-MS / O Method" that they used solvent extraction combined with a solvent-assisted evaporation (SAFE) device to separate and enrich the volatile aroma active components of 18 strong-aroma natural spices, and used gas chromatography-mass spectrometry / olfaction (GC-MS / O) to conduct qualitative and quantitative analysis of the aroma active components. Before SAFE ultra-low temperature extraction, it is also necessary to first use dichloromethane solvent to perform ultrasonic extraction on the spice powder sample, and then perform SAFE extraction on the extract.

[0005] However, the content and proportion of volatile aroma components in the pretreated sample are inevitably affected by the pretreatment method. The product obtained by further SAFE extraction cannot fully reflect the aroma information of the original sample, making the product aroma unnatural or different from the original sample. In fact, this problem exists in most preparative extraction methods: for example, in solvent extraction, substances with similar polarity to the extraction solvent have a higher distribution coefficient, so they can be enriched in the extracted product; in supercritical extraction, the distribution coefficients of different substances in supercritical solvents are not the same, and substances with high distribution coefficients will be enriched; even in solid phase microextraction technology directly targeting gas, the solid phase extraction material will preferentially adsorb certain molecules, resulting in a deviation between the ratio of adsorbed flavor molecules and the ratio in the gas phase. At present, the only real in-situ odor analysis is headspace gas analysis, which uses a larger capacity syringe to collect the gas above the sample, condense or adsorb and focus in the injector, and further inject it into the gas chromatograph. However, the extraction efficiency of headspace gas analysis is extremely low, and the flavor substances obtained are very few, which can only be used for instrumental analysis. In addition, due to the extremely low extraction efficiency and the small absolute mass of the obtained product, it is difficult to accurately obtain the content information of trace components in the subsequent analysis.

[0006] Therefore, at present, for samples containing a large amount of solid or semi-solid components with poor fluidity, there is still a problem that the aroma information of the original sample cannot be accurately reflected when extracting volatile aroma components, and the extraction results are of poor accuracy. Summary of the invention

[0007] The purpose of the present invention is to provide a method for extracting volatile aroma components in solid samples, so as to solve the problem of poor accuracy of extraction results when extracting volatile aroma components in solid samples in the prior art.

[0008] The second object of the present invention is to provide a method for analyzing volatile aroma components in solid samples, so as to solve the problem of poor accuracy of test results in the prior art when testing and analyzing volatile aroma components in solid samples.

[0009] In order to solve the above technical problems, the technical solution of the method for extracting volatile aroma components from solid samples of the present invention is: A method for extracting volatile aroma components in a solid sample comprises the following steps: mixing solid sample powder and fine quartz sand and placing the mixture in a distillation container in a solvent-assisted flavor evaporation device, covering the surface of the mixture formed by mixing the solid sample and the fine quartz sand with coarse quartz sand, installing a filter material at the opening of the channel where the volatile gas in the distillation container flows to the collection container, and then extracting the volatile aroma components using a solvent-assisted flavor evaporation technology, wherein the mesh number of the fine quartz sand is more than 200 meshes, and the mesh number of the coarse quartz sand is less than 60 meshes.

[0010] The present invention provides a pioneering method for extracting volatile aroma components in solid samples. A solvent-assisted flavor evaporation device is used to directly load solid sample powder into a distillation container for extraction. Fine quartz sand in the solid sample can fill the gaps between the samples, so that after the sample is heated, the heat can be conducted to the inside of the sample, thereby improving the extraction efficiency of volatile components in the solid sample. The coarse quartz sand covering the mixture can prevent sample particles from being driven by the airflow during the vacuum process and then entering the collection container. The filter material can block solid particles and prevent them from entering the collection container. The extraction method of the present invention can achieve full extraction of volatile aroma components in solid samples, can fully reflect the aroma information of the original sample, and improve the extraction accuracy of volatile aroma components in solid samples.

[0011] The extraction method provided by the present invention does not need to perform solvent extraction on the solid sample before extraction, and converts the solid sample into a liquid sample, skipping the solvent extraction step, which can avoid the loss or change of volatile aroma components caused by the solution extraction process, and can retain the original aroma components of the sample to a greater extent. The ratio of aroma substances obtained is almost the same as that of the original extract, and the aroma characteristics of the raw material sample are truly restored. The extraction method provided by the present invention has the advantages of high extraction efficiency, no need for solvent extraction pretreatment process, significantly shortened extraction time, avoidance of aroma component loss, and true restoration of the aroma characteristics of the solid raw material.

[0012] In order to further fully extract the volatile flavor components in the solid sample and more accurately reflect the flavor characteristics of the original sample, preferably, the water bath temperature of the solvent-assisted flavor evaporation device is 20-90° C., and the system vacuum degree of the solvent-assisted flavor evaporation device is 10 -2 ~10 -6 Pa.

[0013] In order to further improve the extraction rate of volatile aroma components in solid samples, preferably, the extraction time is 2 to 6 hours.

[0014] In order to further improve the heat transfer efficiency between solid samples, thereby improving the extraction efficiency, and preventing solid sample particles from entering the collection container and affecting the accuracy of subsequent test analysis, preferably, the mass ratio of the solid sample, fine quartz sand and coarse quartz sand is (2~3):(1~1.5):(0.4~0.5); the mesh number of the fine quartz sand is 200~400 mesh, and the mesh number of the coarse quartz sand is 40~60 mesh; the mesh number of the solid sample powder is above 40 mesh.

[0015] In order to further reduce the influence of the odor characteristics of quartz sand on the volatile aroma components in the solid sample, preferably, the fine quartz sand and the coarse quartz sand are calcined at 300-400° C. before use. The calcination at 300-400° C. can remove the odor of the quartz sand, and the calcined quartz sand is odorless and has no influence on the product quality.

[0016] The technical solution of the method for analyzing volatile aroma components in solid samples of the present invention is: A method for analyzing volatile aroma components in a solid sample comprises the following steps: after extracting the volatile aroma components in the solid sample using the extraction method, dissolving the volatile aroma components in a collection container to prepare a test liquid, and testing and analyzing the volatile aroma components in the test liquid.

[0017] The method for analyzing volatile aroma components in solid samples provided by the present invention can greatly improve the types and total amount of volatile aroma components detected by adopting the method for extracting volatile aroma components in solid samples, can retain the original aroma components of the sample to a greater extent, especially the key aroma components, can truly restore the aroma characteristics of the raw material sample to a great extent, fully reflect the aroma information of the original sample, and improve the analysis accuracy of the volatile aroma components in the solid sample; and greatly reduce the detection and analysis time of the volatile aroma components in the solid sample, and the process is simple.

[0018] In order to further improve the dissolution rate of volatile flavor components, preferably, the organic solvent used for dissolution is selected from one or more of ethanol, acetone, dichloromethane, water, propylene glycol, glycerol, petroleum ether and n-hexane.

[0019] In order to further improve the separation effect of each component in the volatile aroma component, preferably, the test analysis is GC-MS analysis, and the chromatographic column used in the GC-MS analysis is a DB-5MS chromatographic column.

[0020] In order to further improve the detection accuracy of volatile aroma components, preferably, the chromatographic conditions during the GC-MS analysis are: the injection port temperature is 260~270°C; the temperature rise program is from 50~60°C to 250~260°C at 2~3°C / min; the sample is injected in a splitless manner at 260~270°C, and the injection volume is 1~2 μL.

[0021] In order to further improve the detection accuracy of volatile aroma components, preferably, the mass spectrometry conditions during the GC-MS analysis are: ion source temperature is 230~240°C, transfer line temperature is 270~280°C; ionization voltage is 70~80 eV, and scanning range is 33~455 amu. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the structure of the SAFE device used in the extraction method of the present invention; Figure 2 This is a physical picture of the SAFE device; Figure 3 for Figure 2 A magnified view of the high vacuum valve in Figure 1; Figure 4 for Figure 2 A magnified view of the hole opening in the figure; Figure 5 for Figure 2 Schematic diagram of fixing the Cambridge filter at the hole opening in FIG. Figure 6 The radar chart of the olfactory evaluation results of the volatile aroma components of glutinous rice fragrance leaves extracted in Example 1; Figure 7 This is a radar chart of the olfactory aroma evaluation results of the volatile aroma components of Zimbabwean tobacco leaves extracted in Example 2; Figure 8 This is a radar chart of the olfactory aroma evaluation results of the volatile aroma components of dried jackfruit extracted in Example 3. DETAILED DESCRIPTION

[0023] The technical conception of the method for extracting volatile aroma components from solid samples of the present invention is as follows: A method for extracting volatile aroma components in a solid sample comprises the following steps: mixing solid sample powder and fine quartz sand and placing the mixture in a distillation container in a solvent-assisted flavor evaporation device, covering the surface of the mixture formed by mixing the solid sample and the fine quartz sand with coarse quartz sand, installing a filter material at the opening of the channel where the volatile gas in the distillation container flows to the collection container, and then extracting the volatile aroma components using a solvent-assisted flavor evaporation technology, wherein the mesh number of the fine quartz sand is more than 200 meshes, and the mesh number of the coarse quartz sand is less than 60 meshes.

[0024] The following problems exist when using the SAFE extraction technology to extract volatile aroma components from solid samples: First, the solid sample powder is scattered with the airflow during vacuuming, contaminating the collection bottle and making it impossible to obtain a pure product, affecting the subsequent accurate testing of volatile aroma components; Second, when using the SAFE extraction technology to extract solid samples, it is necessary to first perform liquid phase extraction on the solid sample to obtain an extract, and then perform solvent-assisted flavor evaporation on the extract to extract the volatile aroma components. Liquid phase extraction causes the loss of volatile aroma components, resulting in the inability to fully extract the volatile aroma components in the solid sample. The extraction results cannot reflect the aroma information of the original sample, and the extraction accuracy is still poor.

[0025] The method for extracting volatile flavor components in a solid sample provided by the present invention directly performs solvent-assisted flavor evaporation extraction on the solid sample in situ, thereby avoiding the loss or change of volatile flavor components caused by liquid phase extraction pretreatment before solid sample extraction, retaining the original flavor components of the sample to a greater extent, truly restoring the flavor characteristics of the raw material, and being easy to operate. The extraction method provided by the present invention has the advantages of high extraction efficiency, no need for solvent extraction pretreatment process, significantly shortened extraction time, avoidance of flavor component loss, and true restoration of the flavor characteristics of the solid raw material.

[0026] In a specific embodiment, the solid sample can be glutinous rice bay leaves, tobacco leaves, dried jackfruit, osmanthus, hops, tangerine peel, prickly ash, roxburghii, rapeseed, etc.

[0027] In a specific embodiment, the solid sample powder is obtained by crushing the air-dried solid sample, or by freezing the air-dried solid sample with liquid nitrogen and then crushing it.

[0028] In a specific embodiment, the distillation container of the solvent-assisted flavor evaporation device is immersed in a constant temperature water bath, and the extraction temperature of the sample is controlled by controlling the water bath temperature of the constant temperature water bath; the collection container is immersed in liquid nitrogen, and liquid nitrogen is also added to the cold trap of the solvent-assisted flavor evaporation device.

[0029] In a specific embodiment, a high vacuum valve is installed at the end of the solvent-assisted flavor evaporation device, which is then connected to a vacuum pump to regulate the system vacuum of the device; the minimum working pressure range of the high vacuum valve needs to be less than 10 -4 Pa can continuously adjust the valve opening and closing size, reduce the pumping speed when the vacuum valve is opened to a smaller degree, reduce the gas flow rate, and reduce the number of solid particles carried by the airflow during the pumping process.

[0030] In a specific embodiment, the filter material can be Cambridge filter disc, filter paper, cotton wool, chemical fiber cloth, screen, microporous breathable membrane.

[0031] In a specific embodiment, when evacuating the air, the air is first evacuated at a lower gas flow rate to prevent the solid sample powder from flying, and then the gas flow rate is slowly increased until the system vacuum degree of the SAFE device reaches the set vacuum degree, at which time the SAFE device enters a stable extraction stage.

[0032] A method for analyzing volatile aroma components in a solid sample comprises the following steps: after extracting the volatile aroma components in the solid sample using the extraction method, dissolving the volatile aroma components in a collection container to prepare a test liquid, and testing and analyzing the volatile aroma components in the test liquid.

[0033] In a specific embodiment, the liquid to be tested is obtained by dissolving the volatile aroma components in the collection container to form an extract, and then concentrating the extract by nitrogen blowing to obtain a concentrated solution, and then taking part of the concentrated solution and compounding it with an organic solvent to form a compound solution, and the compound solution is dried with anhydrous sodium sulfate and filtered through a 0.45-0.5 μm filter membrane.

[0034] In a specific embodiment, the test analysis can be GC-MS, GC-O-MS, GC-IMS, etc.

[0035] The embodiments of the present invention are further described below in conjunction with specific examples. The chemical reagents involved in the following examples are all commercially available conventional products unless otherwise specified.

[0036] 1. Specific embodiments of the method for extracting volatile aroma components from solid samples of the present invention Example 1 The extracting method of volatile aroma components in the glutinous rice fragrant leaves of the present embodiment is as follows: 1) Sample preparation: 500 g of air-dried glutinous rice bay leaves were frozen with liquid nitrogen for 2 min, and then quickly transferred to a grinder for crushing. The crushed powder was passed through a 40-mesh sieve, and the sieved glutinous rice bay leaf powder was freeze-dried in a freeze dryer for later use.

[0037] 2) Extraction: Take 200 g of the sieved glutinous rice and bay leaf powder obtained in step 1) into a ziplock bag, add 100 g of 200 mesh fine quartz sand, shake the ziplock bag to mix evenly to obtain a mixed sample, and then use a funnel to transfer the mixed sample to the SAFE device (such as Figure 1-5 Place the mixture in the distillation flask on the left side of the device (as shown in the figure), and then add 50 g of 40 mesh coarse quartz sand to the distillation flask to evenly cover all the mixed samples. Close the lower valve of the left funnel. Cover the opening of the channel through which the volatile aroma components on the left side of the SAFE device evaporate when flowing through a Cambridge filter, and use a thin wire to tie it up (as shown in the figure). Figure 4-5 After weighing the collection bottle, assemble the SAFE device, set the circulating water bath and constant temperature water bath to 50 °C, add liquid nitrogen to the cold trap, and also use liquid nitrogen to cool the right collection bottle. Close the high vacuum valve on the right end (as shown in the figure). Figure 3 As shown in the figure, turn the valve counterclockwise to close the high vacuum valve; turn the valve clockwise to open the high vacuum valve), turn on the molecular turbo pump, and wait until the vacuum degree of the vacuum pump system reaches 1×10 -3 Pa, slowly open the high vacuum valve, control the gas flow rate, slowly extract the gas from the sample, and slowly reduce the system vacuum of the SAFE device to prevent the powder sample in the distillation flask from flying around. When the powder in the distillation flask on the left no longer appears to be "boiling", the high vacuum valve opening can be further increased until the vacuum degree does not change even if the valve opening is increased, so that the system vacuum of the SAFE device is stabilized at 1×10-3 Pa (this process can be completed in 1-2 minutes), then enter the stable extraction stage, extraction for 2 hours, during which time the liquid nitrogen outside the cold trap and the collection bottle is continuously replenished.

[0038] Example 2 The extraction method of volatile aroma components in the Zimbabwe tobacco leaf of the present embodiment is as follows: 1) Sample preparation: 400 g of air-dried Zimbabwean tobacco leaves were crushed with a pulverizer, and the crushed powder was passed through a 40-mesh sieve. The sieved Zimbabwean tobacco leaf powder was freeze-dried in a freeze dryer for later use.

[0039] 2) Extraction: Take 200 g of the sieved Zimbabwe tobacco powder obtained in step 1) into a ziplock bag, add 100 g of 200-mesh fine quartz sand, shake the ziplock bag to mix evenly, and obtain a mixed sample. Then use a funnel to transfer the mixed sample to the distillation flask on the left side of the SAFE device, and then add 50 g of 40-mesh coarse quartz sand to the distillation flask to evenly cover all the mixed samples. Close the lower valve of the left funnel. Insert 2 g of absorbent cotton into the left channel of the SAFE device. After weighing the collection bottle, assemble the SAFE device, set the circulating water bath temperature and the constant temperature water bath to 20 °C, add liquid nitrogen to the cold trap, and also use liquid nitrogen to cool the outside of the right collection bottle. Close the valve of the high vacuum valve on the right end, turn on the molecular turbo pump, and wait until the system vacuum reaches 1×10 -4 Pa, slowly open the high vacuum valve, control the gas flow rate, slowly extract the gas from the sample, and slowly reduce the system vacuum of the SAFE device to prevent the powder sample in the distillation flask from flying around. When the powder in the distillation flask on the left no longer appears to be "boiling", the high vacuum valve opening can be further increased until the vacuum degree does not change even if the valve opening is increased, so that the system vacuum of the SAFE device is stabilized at 1×10 -4 Pa, then it enters the stable extraction stage, and the extraction lasts for 2 h, during which liquid nitrogen outside the cold trap and the collection bottle is continuously replenished.

[0040] Example 3 The extraction method of volatile aroma components in the dried jackfruit of the present embodiment is as follows: 1) Sample preparation: 2000 g of dried jackfruit was crushed with a grinder, and the crushed powder was passed through a 40-mesh sieve. The sieved jackfruit powder was freeze-dried in a freeze dryer for later use.

[0041] 2) Extraction: Take 1000 g of the sieved jackfruit dry powder obtained in step 1) into a ziplock bag, add 500 g of 400-mesh fine quartz sand, shake the ziplock bag to mix evenly, and obtain a mixed sample. Then use a funnel to transfer the mixed sample to the distillation flask on the left side of the SAFE device, and then add 200 g of 60-mesh coarse quartz sand to the distillation flask to evenly cover all the mixed samples. Close the lower valve of the left funnel. Cover the opening of the left channel of the SAFE device with a Cambridge filter and tie it with fine wire. After weighing the collection bottle, assemble the SAFE device, set the circulating water bath temperature and the constant temperature water tank to 80 °C, add liquid nitrogen to the cold trap, and use liquid nitrogen to cool the outside of the right collection bottle. Close the valve of the high vacuum valve on the right end, turn on the molecular turbine pump (vacuum pump), and wait until the system vacuum reaches 1×10 -4 Pa, slowly open the high vacuum valve, control the gas flow rate, slowly extract the gas from the sample, and slowly reduce the system vacuum of the SAFE device to prevent the powder sample in the distillation flask from flying around. When the powder in the distillation flask on the left no longer appears to be "boiling", the high vacuum valve opening can be further increased until the vacuum degree does not change even if the valve opening is increased, so that the system vacuum of the SAFE device is stabilized at 1×10 -4 Pa, then it enters the stable extraction stage, and the extraction lasts for 3 h, during which liquid nitrogen outside the cold trap and the collection bottle is continuously replenished.

[0042] 2. Specific embodiments of the method for analyzing volatile aroma components in solid samples of the present invention Example 4 The analytical method of volatile aroma components in the glutinous rice fragrant leaves of the present embodiment is as follows: 1) Preparation of the test solution: After the extraction of volatile aroma components in glutinous rice fragrance leaves by the extraction method of Example 1 is completed, the collecting bottle is weighed again to determine the dry weight of the volatile aroma component extract, 5 mL of acetone is added to the collecting bottle to dissolve the volatile aroma component extract to form a primary extract, and after the primary extract is poured out, 5 mL of acetone is added to the collecting bottle twice to form a secondary extract and a tertiary extract, and the primary, secondary and tertiary extracts are all combined to obtain a full extract, and the full extract is concentrated to 5 mL using a nitrogen blower, 0.1 g of the concentrate is transferred, and 9.9 g of acetone (containing phenylethyl acetate, concentration 0.91 μg / mL) is added to form a composite solution, and the composite solution is dried with anhydrous sodium sulfate and filtered through a 0.45 μm filter membrane to obtain a test solution.

[0043] 2) GC-MS analysis: The test solution was subjected to GC-MS analysis. The chromatographic column used in GC-MS analysis was DB-5MS chromatographic column (60 m×0.25 mm×0.25μm). The chromatographic conditions for GC-MS analysis were: injection port temperature was 270℃; temperature program: from 50℃ to 260℃ at 2℃ / min; injection was performed at 270℃ in splitless mode, and the injection volume was 1 μL; the mass spectrometry conditions for GC-MS analysis were: ion source temperature was 230℃, transfer line temperature was 280℃; ionization voltage was 70 eV, and scanning range was 33~455 amu; the GC-MS results were searched using the NIST17 spectral library, and compounds with a matching degree higher than 85% were selected for identification. The identified compounds were semi-quantitatively analyzed using the internal standard method.

[0044] The dry weight of the volatile aroma component extract obtained was 0.134 g; a total of 63 volatile aroma components in glutinous rice bay leaves were identified, and the total amount of volatiles in the concentrate was 25216.92 μg / g.

[0045] Example 5 The analytical method of volatile aroma components in the Zimbabwe tobacco leaf of the present embodiment is as follows: 1) Preparation of the test solution: After the extraction of volatile aroma components in Zimbabwe tobacco leaves by the extraction method of Example 1 is completed, the collecting bottle is weighed again to determine the dry weight of the volatile aroma component extract, 5 mL of ethanol is added to the collecting bottle to dissolve the volatile aroma component extract to form a primary extract, and after the primary extract is poured out, 5 mL of ethanol is added to the collecting bottle twice to form a secondary extract and a tertiary extract, and the primary, secondary and tertiary extracts are all combined to obtain a full extract, and the full extract is concentrated to 5 mL using a nitrogen blower, 0.1 g of the concentrate is transferred, and 9.9 g of ethanol (containing phenylethyl acetate, concentration 0.91 μg / mL) is added to form a composite solution, and the composite solution is dried with anhydrous sodium sulfate and filtered through a 0.45 μm filter membrane to obtain a test solution.

[0046] 2) GC-MS analysis: The test solution was subjected to GC-MS analysis. The chromatographic column used in GC-MS analysis was DB-5MS chromatographic column (60 m×0.25 mm×0.25μm). The chromatographic conditions for GC-MS analysis were: injection port temperature was 270℃; temperature program: from 50℃ to 260℃ at 2℃ / min; injection was performed at 270℃ in splitless mode, and the injection volume was 1 μL; the mass spectrometry conditions for GC-MS analysis were: ion source temperature was 230℃, transfer line temperature was 280℃; ionization voltage was 70 eV, and scanning range was 33~455 amu; the GC-MS results were searched using the NIST17 spectral library, and compounds with a matching degree higher than 80% were selected for identification. The identified compounds were semi-quantitatively analyzed using the internal standard method.

[0047] The dry weight of the volatile aroma component extract was 0.231 g. A total of 67 volatile aroma components were identified in Zimbabwean tobacco leaves, and the total amount of volatiles in the concentrate was 35226.11 μg / g.

[0048] Example 6 The analytical method of volatile aroma components in the dried jackfruit of the present embodiment is as follows: 1) Preparation of the test solution: After the extraction of the volatile flavor components in the dried jackfruit by the extraction method of Example 1 is completed, the collecting bottle is weighed again to determine the dry weight of the volatile flavor component extract, 20 mL of ethanol is added to the collecting bottle to dissolve the volatile flavor component extract to form a primary extract, and after the primary extract is poured out, 20 mL of ethanol is added to the collecting bottle twice to form a secondary extract and a tertiary extract, and the primary, secondary and tertiary extracts are all combined to obtain a total extract, and the total extract is concentrated to 20 mL using a nitrogen blowdown instrument, 0.1 g of the concentrate is transferred, and 9.9 g of ethanol (containing phenylethyl acetate, concentration 0.91 μg / mL) is added to form a composite solution, and the composite solution is dried with anhydrous sodium sulfate and filtered through a 0.45 μm filter membrane to obtain a test solution.

[0049] 2) GC-MS analysis: The test solution was subjected to GC-MS analysis. The chromatographic column used in GC-MS analysis was DB-5MS chromatographic column (60 m×0.25 mm×0.25μm). The chromatographic conditions for GC-MS analysis were: injection port temperature was 270℃; temperature program: from 50℃ to 260℃ at 2℃ / min; injection was performed at 270℃ in splitless mode, and the injection volume was 1 μL; the mass spectrometry conditions for GC-MS analysis were: ion source temperature was 230℃, transfer line temperature was 280℃; ionization voltage was 70 eV, and scanning range was 33~455 amu; the GC-MS results were searched using the NIST17 spectral library, and compounds with a matching degree higher than 80% were selected for identification. The identified compounds were semi-quantitatively analyzed using the internal standard method.

[0050] The dry weight of the volatile aroma component extract was 0.532 g. A total of 45 volatile aroma components were identified in dried jackfruit, and the total amount of volatiles in the concentrate was 87211.35 μg / g.

[0051] 3. Comparison Comparative Example 1 The analysis method of the volatile aroma components in the glutinous rice fragrant leaves of this comparative example is as follows: 1) In this comparative example, glutinous rice bay leaves are subjected to ultrasound-assisted extraction-solvent-assisted flavor evaporation to extract volatile flavor components. The specific method is as follows: 500 g of air-dried glutinous rice bay leaves were frozen with liquid nitrogen for 2 min, and then quickly transferred to a grinder for crushing. The crushed powder was passed through a 40-mesh sieve, and the sieved glutinous rice bay leaf powder was freeze-dried in a freeze dryer for later use.

[0052] Take 200 g of the sieved glutinous rice bay leaf powder obtained in step 1) into a beaker, add 800 mL of ethanol, and extract for 30 minutes at an ultrasonic power of 600 W. After the extraction, use a suction filtration device to achieve solid-liquid separation to obtain an extract.

[0053] The extract was added to the glass funnel of the SAFE device. The circulating water bath temperature and the constant temperature water tank of the SAFE device were set to 50 °C. Liquid nitrogen was added to the cold trap and the molecular turbo pump was turned on. The vacuum of the system reached 1×10 -3 Pa, slowly open the stopcock of the dropping funnel and control the flow rate of the solvent so that it drips slowly and evenly into the distillation flask. The extraction time is 2 h.

[0054] 2) GC-MS analysis After the extraction is completed, the extract obtained in the collection bottle is naturally melted at room temperature, and then spin-dried and weighed using a rotary evaporator to obtain the dry weight of the volatile aroma component extract. After weighing, the extract in the collection bottle is transferred to a 5 mL volumetric flask using acetone to make up the volume. 0.1 g of the extract is transferred, 9.9 g of acetone (containing phenylethyl acetate, concentration 0.91 μg / mL) is added, and the test solution is obtained after drying with anhydrous sodium sulfate and filtering through a 0.45 μm filter membrane.

[0055] The liquid to be tested was analyzed by GC-MS. The chromatographic column used in GC-MS analysis was DB-5MS chromatographic column (60 m×0.25 mm×0.25μm). The chromatographic conditions for GC-MS analysis were: injection port temperature was 270℃; temperature program: from 50℃ to 260℃ at 2℃ / min; injection was performed at 270℃ in splitless mode, and the injection volume was 1 μL; the mass spectrometry conditions for GC-MS analysis were: ion source temperature was 230℃, transfer line temperature was 280℃; ionization voltage was 70 eV, and scanning range was 33~455 amu; the GC-MS results were searched using the NIST17 spectral library, and compounds with a matching degree higher than 80% were selected for identification. The identified compounds were semi-quantitatively analyzed using the internal standard method.

[0056] The dry weight of the volatile aroma component extract obtained was 0.153 g; a total of 48 volatile aroma components in glutinous rice bay leaves were identified, and the total amount of volatiles in the concentrate was 22023.5 μg / g.

[0057] Compared with the extraction method of Example 1 of the present invention, the types of volatile aroma components identified in this comparative example are significantly reduced, reduced by nearly 1 / 4, and the total amount of volatiles is also significantly reduced, indicating that the extraction method of the present invention can greatly increase the types and extraction amount of volatile aroma components, can achieve full extraction of volatile aroma components in solid samples, can fully reflect the aroma information of the original sample, and improve the extraction accuracy of volatile aroma components in solid samples.

[0058] Comparative Example 2 The method for extracting volatile aroma components from glutinous rice leaves in this comparative example is basically the same as that in Example 1, except that: in step 2), 100 g of 200-mesh fine quartz sand is not added, 200 g of sieved glutinous rice leaves powder is directly transferred to the distillation flask on the left side of the SAFE device using a funnel, and then 50 g of 40-mesh coarse quartz sand is added to the distillation flask to evenly cover the glutinous rice leaves powder.

[0059] After the extraction is completed by the above extraction method, the volatile aroma components in the collection container are dissolved to prepare a test liquid, and the test liquid is subjected to GC-MS analysis.

[0060] The dry weight of the volatile aroma component extract obtained was 0.039 g; the total amount of volatile matter in the concentrate was 6523.25 μg / g.

[0061] Compared with the extraction method of volatile aroma components in glutinous rice bay leaves of the present invention, the dry weight of the volatile aroma component extract obtained in this comparative example is reduced by nearly 3 / 4, and the total amount of volatiles is reduced by nearly 3 / 4, indicating that the extraction method of the present invention can greatly increase the extraction amount of volatile aroma components and greatly improve the extraction efficiency.

[0062] Comparative Example 3 The method for extracting volatile aroma components from glutinous rice fragrance leaves in this comparative example is basically the same as that in Example 1, except that: 50 g of 40-mesh coarse quartz sand is not added in step 2).

[0063] The extraction experiment of this comparative example could not be carried out, and a small amount of glutinous rice bay leaf powder entered the collecting bottle.

[0064] Comparative Example 4 The method for extracting volatile aroma components from glutinous rice bay leaves in this comparative example is basically the same as that in Example 1, except that: in step 2), the opening of the channel on the left side of the SAFE device is not covered with the Cambridge filter.

[0065] The extraction experiment of this comparative example could not be carried out, and a large amount of glutinous rice bay leaf powder entered the collecting bottle.

[0066] IV. Experimental Examples Experimental Example 1 The quantitative test results of the volatile aroma components in the solid samples of the present invention are shown in Tables 1-3.

[0067] Table 1 Quantitative test results of volatile aroma components in glutinous rice fragrance leaves of Example 4 and Comparative Examples 1-2 Note: “-” means not detected.

[0068] Table 1 shows the quantitative test results of the analytical method for the volatile aroma components in the glutinous rice leaves of Example 4 and Comparative Examples 1-2. It can be seen from Table 1 combined with the above analytical test results that, compared with ultrasound-assisted extraction-solvent-assisted flavor evaporation (Comparative Example 1), the extraction method provided by the present invention can extract more types of volatile aroma components from the glutinous rice leaves sample, and the total amount of volatile aroma components extracted is also higher; the key aroma components 2-propionyl-3,4,5,6-tetrahydropyridine, 2-propionyl-1, The contents of 4,5,6-tetrahydropyridine and 2-acetyl-3,4,5,6-tetrahydropyridine are significantly lower than those in Example 4. These substances are the main substances that make the glutinous rice fragrant leaves present rice aroma. Therefore, the aroma detected in Example 4 clearly has the characteristics of rice aroma, while the rice aroma characteristics of Comparative Example 1 are weaker. The reason for this phenomenon is that these rice aroma components are all imine molecules, which are unstable in nature and easily decomposed when exposed to water, light and heat. Most extraction methods easily lead to the decomposition of these molecules, thereby reducing the extraction efficiency of these molecules and causing the aroma to change.

[0069] Compared with not adding fine quartz sand (Comparative Example 2), the extraction method provided by the present invention can extract a higher total amount of volatile aroma components from the glutinous rice fragrance leaf sample, and the content of each type of volatile aroma components is also higher. This should be because the non-addition of fine quartz sand leads to uneven heat transfer, resulting in low extraction efficiency; and, the key aroma component 2-acetyl-3,4,5,6-tetrahydropyridine in the glutinous rice fragrance leaves of Comparative Example 2 can no longer be detected. The extraction method of Comparative Example 2 will affect the detection of key aroma components in the sample, resulting in the loss of aroma information of the original sample, which reduces the extraction accuracy of volatile aroma components in the solid sample.

[0070] Table 2 Quantitative test results of volatile aroma components in Zimbabwe tobacco leaves of Example 5 CAS Number Chinese name Relative content (μg / g) 54-11-5 Nicotine 11159.4516 67-47-0 5-Hydroxymethylfurfural 925.48659 874-90-8 4-Methoxybenzene cyanocyanide 788.03394 32736-94-0 2,5-Dimethyl-3-isobutylpyrazine 496.55982 104-93-8 p-Toluene 496.55982 93-53-8 2-Phenylpropanal 374.99499 100-6-9 2-Vinylpyridine 374.99499 540-88-5 Tert-Butyl Acetate 165.732732 582-16-1 2,7-Dimethylnaphthalene 71.026584 5405-41-4 Ethyl 3-Hydroxybutyrate 66.963396 110-85-0 Piperazine 63.320013 3855-78-5 2,3,4-Trimethylpyrrole 61.626111 13925-06-9 2-Methyl-3-(2-methylpropyl)pyrazine 61.626111 150-84-5 Citronellyl acetate 56.543301 141-14-0 Citronellyl Propionate 56.543301 94-59-7 Safrole 50.639181 Table 3 Quantitative test results of volatile aroma components in dried jackfruit of Example 6 CAS Number name Relative content (μg / g) 108-64-5 Ethyl isovalerate 1713 105-54-4 Ethyl butyrate 1570 590-86-3 Isovaleraldehyde 859 78-84-2 Isobutyraldehyde 539 123-72-8 Butyraldehyde 502 112-31-2 Decanal 1290 66-25-1 Hexanal 653 556-24-1 Methyl isovalerate 721 503-74-2 Isovalerate 11325 7452-79-1 Ethyl 2-methylbutyrate 103 75-18-3 Dimethyl sulfide 104 96-17-3 2-Methylbutyraldehyde 239 513-86-0 Acetoin 10621 431-03-8 Diacetyl 61.7 3658-77-3 Furanone 3090 2021-28-5 Ethyl phenylpropionate 23.1 3268-49-3 Methylthiopropionaldehyde 44.1 123-51-3 Isoamyl alcohol 5460 Experimental Example 2 In this experimental example, the volatile aroma components extracted from the solid sample were evaluated for olfactory aroma. The specific method is as follows: 1) Preparation of the solution to be evaluated: 1g of the concentrated solution made of the volatile aroma components obtained by the extraction method of Examples 1-3 was taken respectively, concentrated to 0.5g by a nitrogen blower, and 4.5g of propylene glycol was added to prepare the solution to be evaluated for olfactory aroma evaluation; 2) Odor evaluation: The solution to be evaluated was stored in a 10 mL vial and placed at room temperature for 24 hours under airtight and light-proof conditions. Another 1g solid sample powder was prepared as the original sample and placed in the same vial. The aroma dimensions of milk aroma, flower aroma, fruit aroma, baking, spicy aroma, green fragrance, paste aroma, and rice aroma were evaluated. Each item was scored 0-10 points. The higher the score, the stronger the corresponding aroma. The evaluation results were expressed as a radar chart. The aroma score of the original sample is the normalized score. This is because the aroma of the original sample is too weak compared to the concentrated sample, which is not convenient for direct comparison.

[0071] Example 1 The olfactory evaluation results of the volatile aroma components of the glutinous rice bay leaves extracted are shown in the radar chart. Figure 6 As shown. Figure 6 It can be seen that compared with ultrasound-assisted extraction-solvent-assisted flavor evaporation (Comparative Example 1), the extract obtained by the extraction method of the present invention has a more significant rice aroma, and its overall aroma characteristics are very close to the original glutinous fragrant leaf sample (original); while the extract obtained in Comparative Example 1 is obviously lacking in the dimension of rice aroma and is too prominent in the green fragrance. This result shows that the extraction method provided by the present invention can better retain the aroma substances in the sample and obtain an extract whose aroma substance ratio is closer to the original sample.

[0072] Example 2 The olfactory evaluation results of the volatile aroma components of Zimbabwe tobacco leaves extracted are shown in the radar chart below: Figure 7 As shown, the olfactory evaluation results of the volatile aroma components of the dried jackfruit extracted in Example 3 are shown in the radar chart. Figure 8 As shown. Figure 7-8 It can be seen that the ratio of aroma substances obtained by the extraction method provided by the present invention is almost the same as that of the original extract, indicating that the extraction method provided by the present invention can better retain the aroma substances in the sample.

[0073] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for extracting volatile aroma components from a solid sample, characterized in that: The following steps are involved: A solid sample powder and fine quartz sand are mixed and placed in a distillation container in a solvent-assisted flavor evaporation device, and the surface of the mixture formed by the solid sample and the fine quartz sand is covered with coarse quartz sand. A filter material is installed at the opening of the channel where the volatile gas in the distillation container flows to the collection container, and then the solvent-assisted flavor evaporation technology is used to extract the volatile aroma components. The mesh number of the fine quartz sand is more than 200 meshes, and the mesh number of the coarse quartz sand is less than 60 meshes.

2. The method for extracting volatile aroma components from a solid sample according to claim 1, characterized in that: The water bath temperature of the solvent-assisted flavor evaporation device is 20-90° C., and the system vacuum degree of the solvent-assisted flavor evaporation device is 10 -2 ~10 -6 Pa.

3. The method for extracting volatile aroma components from a solid sample according to claim 1, characterized in that: The extraction time is 2 to 6 hours.

4. The method for extracting volatile aroma components from a solid sample according to claim 1, characterized in that: The mass ratio of the solid sample, fine quartz sand and coarse quartz sand is (2-3): (1-1.5): (0.4-0.5); the mesh size of the fine quartz sand is 200-400 mesh, the mesh size of the coarse quartz sand is 40-60 mesh; the mesh size of the solid sample powder is above 40 mesh.

5. The method for extracting volatile aroma components from a solid sample according to claim 1, characterized in that: The fine quartz sand and the coarse quartz sand are both calcined at 300-400°C before use.

6. A method for analyzing volatile aroma components in a solid sample, characterized in that: The following steps are involved: After the extraction is completed by the method for extracting volatile aroma components from a solid sample according to any one of claims 1 to 5, the volatile aroma components in the collection container are dissolved to prepare a test liquid, and the volatile aroma components in the test liquid are tested and analyzed.

7. The method for analyzing volatile aroma components in a solid sample according to claim 6, characterized in that: The organic solvent used for dissolving is selected from one or more of ethanol, acetone, dichloromethane, water, propylene glycol, glycerol, petroleum ether and n-hexane.

8. The method for analyzing volatile aroma components in a solid sample according to claim 6, characterized in that: The test analysis is GC-MS analysis, and the chromatographic column used in the GC-MS analysis is a DB-5MS chromatographic column.

9. The method for analyzing volatile aroma components in a solid sample according to claim 8, characterized in that: The chromatographic conditions for the GC-MS analysis are as follows: injection port temperature of 260-270°C; temperature program: from 50-60°C to 250-260°C at 2-3°C / min; injection at 260-270°C in splitless mode, with an injection volume of 1-2 μL.

10. The method for analyzing volatile aroma components in a solid sample according to claim 8, characterized in that: The mass spectrometry conditions during the GC-MS analysis are: ion source temperature of 230-240° C., transfer line temperature of 270-280° C., ionization voltage of 70-80 eV, and scanning range of 33-455 amu.

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