Method for extracting volatile substances in fruits, fruit essence and atomized liquid

Abstract

The invention relates to the technical field of substance extraction, in particular to a method for extracting volatile substances in fruits, fruit essence and atomized liquid. The method comprises the following steps: performing crushing treatment on fruit raw materials, and performing freezing and thawing cycle treatment on the crushed dices to obtain pretreated fruit raw materials; treating the pretreated fruit raw materials by using a hydrophobic deep-eutectic solvent to obtain a raw material mixed solution; through a supercritical CO2 dynamic extraction technology, a volatile substance extract is obtained from a raw material mixed solution, and the volatile substance extract is subjected to separation treatment to obtain the volatile substance. According to the method, the fruit raw materials are subjected to freeze-thaw cycle treatment, so that cell walls of substances can be weakened, the components can be dissolved more quickly and better subsequently, the recovery rate of the volatile substances can be increased, and the reproducibility is good.

Description

Technical Field

[0001] This application relates to the field of material extraction technology, specifically to a method for extracting volatile substances from fruits and fruit flavorings and atomized liquids. Background Technology

[0002] To enhance the user experience, fruit flavorings are often added to e-liquids used in electronic devices. Therefore, how to obtain flavorings from fruits has become an important research objective.

[0003] Currently, the main technologies for obtaining flavorings from fruits include: traditional solvent extraction, pressing / mechanical crushing, ultrasonic / microwave-assisted extraction, and enzymatic hydrolysis. However, these technologies have certain drawbacks, such as incomplete dissolution by organic solvents and overly harsh extraction processes and conditions, leading to flavoring oxidation. These drawbacks result in very low flavoring recovery rates. Summary of the Invention

[0004] This application provides a method for extracting volatile substances from fruits, as well as fruit flavorings and atomized liquids. This method can improve the recovery rate of volatile substances from fruits.

[0005] This application provides a method for extracting volatile substances from fruits. The method includes: crushing fruit raw materials and subjecting the crushed pieces to freeze-thaw cycles to obtain pretreated fruit raw materials; treating the pretreated fruit raw materials with a hydrophobic eutectic solvent to obtain a raw material mixture; obtaining a volatile substance extract from the raw material mixture using supercritical CO2 dynamic extraction technology, and separating the volatile substance extract to obtain volatile substances.

[0006] In one embodiment, the freeze-thaw cycle treatment of the pulverized diced fruit includes: placing the pulverized diced fruit at a preset temperature for a preset time and then restoring it to room temperature; after repeating the above operation, adding an antioxidant to the diced fruit after the last cycle to obtain the pretreated fruit raw material.

[0007] In one embodiment, the process of treating the pretreated fruit raw material with a hydrophobic eutectic solvent to obtain a raw material mixture includes: mixing decanoic acid and thymol or choline and lactic acid, stirring until a transparent liquid is obtained to obtain a hydrophobic eutectic solvent; mixing the pretreated fruit raw material and the hydrophobic eutectic solvent, followed by ultrasonic and separation treatment, and using the separated hydrophobic eutectic solvent phase as the raw material mixture.

[0008] In one embodiment, obtaining a volatile substance extract from the raw material mixture using supercritical CO2 dynamic extraction technology includes: loading the raw material mixture into an extraction vessel and introducing liquid carbon dioxide; inserting an ultrasonic probe into the extraction vessel and obtaining the volatile substance extract through intermittent extraction; and / or, processing the volatile substance extract to obtain volatile substances includes: setting multiple different temperature zones in a rotating conical column distillation column, injecting the volatile substance extract into the rotating conical column distillation column for separation to obtain condensates corresponding to each different temperature zone; injecting the condensates of each different temperature zone into an adsorption column for adsorption, and obtaining various volatile substances through desorption.

[0009] In one embodiment, the pulverization temperature is 2-6°C; and / or, the size of the pulverized pieces is 0.5mm-2mm; and / or, the preset temperature is -15--20°C; and / or, the antioxidant includes at least one of the following: ascorbic acid, sodium D-isoascorbate, butylated hydroxyanisole, and antioxidant B215; and / or, the ratio of the mass of the fruit raw material to the volume of the antioxidant is 1:1; and / or, the pH of the pretreated fruit raw material is 5-6; and / or, the preset freezing time is 5-15 minutes; and / or, the number of cycles is 2-4.

[0010] In one embodiment, the molar ratio of decanoic acid to thymol is 1:(2~4); and / or, the molar ratio of choline to lactic acid is 1:(2~4); and / or, the stirring temperature is 50~80℃; and / or, the ultrasonic treatment conditions include: ultrasonic power of 40~100KHz, ultrasonic temperature of 20~30℃, and ultrasonic time of 10~30min; and / or, the mass ratio of the pretreated fruit raw material to the hydrophobic eutectic solvent is 1:(3~7).

[0011] In one embodiment, the process parameters for the intermittent extraction include: a temperature of 30-50°C, a pressure of 20-30 MPa, a frequency of 30-50 kHz for the ultrasonic probe, a flow rate of 15-25 L / h for liquid carbon dioxide, a total extraction time of 50-70 min, a single extraction time of 40-80 s, and an extraction interval of 20-40 s.

[0012] In one embodiment, the rotating conical column distillation column is provided with different temperature zones at the top, middle, and bottom; wherein the top temperature is 30~50℃, the middle temperature is 50~70℃, and the bottom temperature is 70~90℃; and / or, the vacuum degree of the rotating conical column distillation column is 0.1~0.5kPa; and / or, the rotational speed of the rotating conical column is 2500~3500rpm / min; and / or, the adsorbent in the adsorption columns corresponding to the top condensate and the middle condensate is ZSM-5 type zeolite; and / or, the adsorbent in the adsorption column corresponding to the bottom condensate is activated carbon fiber felt; and / or, the process parameters for injecting the top condensate into the adsorption column include: a flow rate of 8~12mL / min and a temperature of 23~27℃; and / or, the process parameters for injecting the middle condensate into the adsorption column include: a flow rate of 3~7mL / min and a temperature of The process parameters for injecting the bottom condensate into the adsorption column include: a flow rate of 1-4 mL / min and a temperature of 48-52 °C; and / or the desorption conditions for the top condensate include: a temperature of 28-32 °C, a nitrogen flow rate of 28-32 mL / min, an isothermal desorption time of 28-32 min, and a cold trap collection temperature of -28 to -32 °C; and / or the desorption conditions for the middle condensate include: a temperature of 38-42 °C, a nitrogen flow rate of 18-22 mL / min, an isothermal desorption time of 28-32 min, and a cold trap collection temperature of -58 to -62 °C; and / or the desorption conditions for the bottom condensate include: a temperature of 58-62 °C, a nitrogen flow rate of 8-12 mL / min, an isothermal desorption time of 28-32 min, and a cold trap collection temperature of -88 to -92 °C.

[0013] This application also provides a fruit flavoring, which includes volatile substances obtained by the above method.

[0014] This application also provides an atomizing liquid, characterized in that the atomizing liquid contains fruit flavoring.

[0015] This application involves low-temperature treatment of fruit raw materials, such as crushing and freeze-thaw cycles. This weakens the cell walls of the materials, making it easier for the components to dissolve more quickly and effectively, thereby improving the recovery rate of volatile substances and enhancing reproducibility. Attached Figure Description

[0016] Figure 1 This is a flowchart of a method for extracting volatile substances in one embodiment. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0018] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0019] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0020] To address the technical problems mentioned in the background, this embodiment provides the following... Figure 1 The method for extracting volatile substances shown includes: S1. The fruit raw material is crushed and the crushed pieces are subjected to freeze-thaw cycle treatment to obtain pre-treated fruit raw material; S2. The pretreated fruit raw materials are treated with a hydrophobic eutectic solvent to obtain a raw material mixture; S3. A volatile substance extract is obtained from the raw material mixture using supercritical CO2 dynamic extraction technology, and the volatile substance extract is further separated to obtain volatile substances.

[0021] This method involves freeze-thaw cycles for fruit raw materials, which weakens the cell walls of the substances, making it easier for each component to dissolve faster and better, thereby improving the recovery rate and reproducibility.

[0022] Step S1 specifically includes: S11. At 2~6℃, the fruit raw material is crushed to obtain crushed diced pieces; S12. Place the chopped pieces at a preset temperature to freeze, then restore them to room temperature, and repeat the process by placing them at a preset low temperature again. S13. Antioxidants are added to the recycled crushed fruit to obtain pretreated fruit raw materials.

[0023] This method employs low-temperature freeze-thaw cycles to weaken cell walls, followed by treatment with a eutectic solvent (DES solvent). The process is safe and reliable, eliminating the toxicity and pollution associated with organic solvents used in traditional solvent extraction methods. Furthermore, it enhances the dissolution effect, thereby indirectly improving the recovery rate of volatile substances.

[0024] The size of the small pieces ranges from 0.5mm to 2mm.

[0025] This size of diced material is not only easy to handle, but also allows for a better effect in the subsequent cryogenic freeze-thaw cycle to weaken the cell walls of the raw material.

[0026] Specifically, the size of the small pieces can be 0.8, 1, 1.2, 1.5, 1.6, or 1.8 mm.

[0027] The preset temperature is -15 to -20°C; the freezing time is 5 to 15 minutes; and the number of cycles is 2 to 4. The principle of low-temperature freeze-thaw cycle technology is mainly to weaken the cell walls of fruits at low temperatures, so that the subsequent DES extraction can be better, which can greatly improve the recovery rate of low-content esters, terpenes and other substances.

[0028] Specifically, the pulverization temperature can be 3, 4, or 5℃ or any value within the above range; the preset temperature can be -16, -17, -18, or -19℃ or any value within the above range; the freezing time can be 8, 10, 12, or 14 minutes or any value within the above range; and the number of cycles can be 3 or any value within the above range.

[0029] The antioxidants include at least one of the following: ascorbic acid, sodium D-isoascorbate, butylated hydroxyanisole, and antioxidant B215.

[0030] The pretreated fruit raw materials have a pH of 5-6. Slightly acidic conditions help to soften cell wall components such as pectin in the fruit tissue, increasing permeability and allowing DES to more easily enter the cells and dissolve the target components. Furthermore, under slightly acidic conditions, stronger hydrogen bonds, ionic interactions, or hydrophobic interactions may form between the target compound and the DES components. For many substances such as polyphenols, their ionized state at pH 5-6 is most favorable for binding to hydrogen bond donor / acceptor sites in DES, thereby improving their efficiency in transferring from the matrix to the solvent.

[0031] Specifically, the pH of the pretreated fruit raw materials can be 5.2, 5.4, 5.6, 5.8 or any value within the above range.

[0032] Step S2 specifically includes: S21. Mix decanoic acid and thymol or choline and lactic acid, and stir until a transparent liquid is obtained to obtain a hydrophobic eutectic solvent. S22. The pretreated fruit raw materials and the hydrophobic eutectic solvent are mixed and treated by ultrasound and centrifugation. The separated hydrophobic eutectic solvent phase is used as the raw material mixture.

[0033] The molar ratio of decanoic acid to thymol is 1:(2~4); the molar ratio of choline to lactic acid is 1:(2~4). Decanoic acid and thymol, or choline and lactic acid, form a hydrophobic low co-solubility solvent in a specific ratio. Many components in fruits are hydrophobic, so this solvent has good solubility in them, and they also have good biocompatibility and safety.

[0034] Specifically, the molar ratio of decanoic acid to thymol is 1:2.5, 1:3, 1:3.5 or any value within the above range; the molar ratio of choline to lactic acid is 1:2.5, 1:3, 1:3.5 or any value within the above range.

[0035] The mass ratio of the pretreated fruit raw material to the hydrophobic eutectic solvent is 1:(3~7). To better ensure the dissolution of the wax layer in the pretreated fruit raw material, mixing at this ratio not only minimizes the amount of solvent used but also ensures complete dissolution.

[0036] Specifically, the mass ratio of the pretreated fruit raw material to the hydrophobic eutectic solvent can be 1:4, 1:5, 1:6, or any value within the above range.

[0037] The stirring temperature is 50~80℃. Specifically, it can be 55, 60, 65, 70, 75℃ or any value within the above range. The ultrasonic parameters include: ultrasonic power of 40~100KHz, ultrasonic temperature of 20~30℃, and ultrasonic time of 10~30min.

[0038] The appropriate temperature and time are set according to the physicochemical properties of the pretreated fruit raw materials and the hydrophobic eutectic solvent. At this temperature and time, the high-frequency vibration of ultrasound and related effects are used to make the molecules, ions or particles in the liquid collide with each other to reach a high energy state, thereby making the mixing speed faster and the mixing effect better.

[0039] Specifically, the ultrasonic power can be 50, 60, 70, 80, 90 kHz or any value within the above range; the ultrasonic temperature can be 22, 25, 26℃ or any value within the above range; and the ultrasonic time can be 15, 20, 25 min or any value within the above range.

[0040] Step S3 specifically includes: S31. Load the raw material mixture into the extraction vessel and introduce liquid carbon dioxide; S32. Insert the ultrasonic probe into the extraction vessel and obtain the volatile substance extract through intermittent extraction.

[0041] S33. The volatile substance extract is injected into a rotating conical column distillation column with different temperature gradients for separation to obtain the corresponding multi-stage condensate. S34. Inject the multi-stage condensate into the adsorption column for adsorption and desorption to obtain the corresponding volatile substances.

[0042] This supercritical CO2 dynamic extraction method employs an intermittent extraction mode, avoiding the problem of high temperatures potentially damaging thermally unstable components and reducing material recovery rates, as seen in ultrasonic or microwave-assisted extraction methods. The rotating cone column (SCC) online separation utilizes a temperature gradient to separate substances, improving the recovery rate of volatile compounds. Furthermore, the adsorption-desorption coupled low-temperature desorption (BET) process uses three-stage cold traps to capture substances, further enhancing the recovery rate of volatile compounds.

[0043] The process parameters for batch extraction include: temperature 30–50℃, pressure 20–30 MPa, ultrasonic probe frequency 30–50 kHz, liquid carbon dioxide flow rate 15–25 L / h, total extraction time 50–70 min, single extraction time 40–80 s, and extraction interval 20–40 s. Batch extraction avoids localized overheating, as high temperatures can cause substance decomposition, reducing recovery rates, and may also trigger complex chemical reactions leading to byproducts with uncertain safety.

[0044] Specifically, the batch extraction temperature is 35, 40, or 45°C or any value within the above range; the pressure is 22, 26, or 28 MPa or any value within the above range; the ultrasonic probe frequency is 35, 40, or 45 kHz or any value within the above range; the liquid carbon dioxide flow rate is 18, 20, or 22 L / h or any value within the above range; the total extraction time is 55, 60, or 65 min or any value within the above range; the single extraction time is 50, 60, or 70 s or any value within the above range; and the extraction interval is 25, 30, or 35 s or any value within the above range.

[0045] The temperature gradient of the rotating conical column distillation column includes: a top temperature of 30~50℃, a middle temperature of 50~70℃, and a bottom temperature of 70~90℃; the vacuum degree of the rotating conical column distillation column is 0.1~0.5kpa; and the rotation speed of the rotating conical column is 2500~3500rpm / min.

[0046] The parameters of the rotating conical column distillation column are set according to the boiling points of the volatile substances. For example, different temperature gradients are set to capture different substances. The top mainly captures low-molecular-weight volatile esters (ethyl acetate, ethyl butyrate, etc.), the middle captures medium-polar alcohols (hexanol, linalool, etc.), and the bottom captures high-boiling-point ketones and lactones (β-ionone, γ-decyl lactone, etc.). This allows volatile substances with different boiling points to be separated in the corresponding parts, ensuring that each volatile substance is completely separated and thus guaranteeing its recovery rate.

[0047] Specifically, the top temperature is 35, 40, or 45°C or any value within the above range; the middle temperature is 55, 60, or 65°C or any value within the above range; the bottom temperature is 75, 80, or 85°C or any value within the above range; the vacuum degree of the rotating conical column distillation column is 0.2, 0.3, or 0.4 kPa or any value within the above range; and the rotational speed of the rotating conical column is 2800, 3000, or 3200 rpm / min or any value within the above range.

[0048] The adsorbent in the adsorption columns corresponding to the top and middle condensates is ZSM-5 zeolite; the adsorbent in the adsorption column corresponding to the bottom condensate is activated carbon fiber felt.

[0049] By selecting appropriate adsorbents based on the characteristics of volatile substances in condensate from different locations, the adsorption effect of volatile substances can be improved, thereby ensuring that each volatile substance can be fully adsorbed and increasing the final recovery rate of volatile substances.

[0050] Specifically, the ZSM-5 type zeolite adsorbent has a silica-to-alumina ratio >200 and a particle size of 80-100 mesh. The specific surface area of ​​activated carbon fiber felt is ≥1500 m² / g. Of course, other adsorbents that can achieve the same effect are also applicable.

[0051] The process parameters for injecting top condensate into the adsorption column include: a flow rate of 8~12 mL / min and a temperature of 23~27℃; the process parameters for injecting middle condensate into the adsorption column include: a flow rate of 3~7 mL / min and a temperature of 33~37℃; and the process parameters for injecting bottom condensate into the adsorption column include: a flow rate of 1~4 mL / min and a temperature of 48~52℃.

[0052] Selecting the appropriate speed and temperature based on the characteristics of volatile substances in the condensate at different locations not only allows for better transport of these volatile substances and improved efficiency, but also maximizes the provision of a favorable adsorption environment for them. This facilitates better adsorption of each volatile substance onto its corresponding adsorption column, thereby increasing the final recovery rate of the volatile substances.

[0053] Specifically, the injection rate of the top condensate into the adsorption column is 9, 10, or 11 mL / min or any value within the above range, and the temperature is 24, 25, or 26°C or any value within the above range; the injection rate of the middle condensate into the adsorption column is 4, 5, or 6 mL / min or any value within the above range, and the temperature is 34, 35, or 36°C or any value within the above range; the injection rate of the bottom condensate into the adsorption column is 2 or 3 mL / min or any value within the above range, and the temperature is 49, 50, or 51°C or any value within the above range.

[0054] The desorption conditions for the top condensate include: temperature 28–32°C, nitrogen flow rate 28–32 mL / min, isothermal desorption time 28–32 min, and cold trap collection temperature -28–-32°C. For the middle condensate, the conditions are: temperature 38–42°C, nitrogen flow rate 18–22 mL / min, isothermal desorption time 28–32 min, and cold trap collection temperature -58–-62°C. For the bottom condensate, the conditions are: temperature 58–62°C, nitrogen flow rate 8–12 mL / min, isothermal desorption time 28–32 min, and cold trap collection temperature -88–-92°C. This desorption cold trap collection method uses different low temperatures to collect substances with different boiling points, resulting in better performance and higher recovery rates compared to traditional single-temperature range collection.

[0055] Specifically, the desorption temperature of the top condensate is 29, 30, or 31°C or any value within the above range; the nitrogen flow rate is 29, 30, or 31 mL / min or any value within the above range; the isothermal desorption time is 29, 30, or 31 min or any value within the above range; and the cold trap collection temperature is -29, -30, or -31°C or any value within the above range. The desorption temperature of the middle condensate is 39, 40, or 41°C or any value within the above range; and the nitrogen flow rate is 19, 20, or 21 mL / min or any value within the above range. The values ​​are as follows: isothermal desorption time is 29, 30, or 31 min or any value within the above range; cold trap collection temperature is -58, -59, -60, or -61 °C or any value within the above range; bottom condensate desorption temperature is 59, 60, or 61 °C or any value within the above range; nitrogen flow rate is 9, 10, or 11 mL / min or any value within the above range; isothermal desorption time is 29, 30, or 31 min or any value within the above range; cold trap collection temperature is -89, -90, or -91 °C or any value within the above range.

[0056] To better understand this application, embodiments and comparative examples are also provided below.

[0057] Example 1 1. Place 10 grams of fresh mango raw material in a 4℃ refrigerator and cut the pulp and peel into 1mm small pieces. Use freeze-thaw cycle technology to freeze the raw material at -20℃ for 10 minutes, then take it out and bring it to room temperature, then freeze it at -20℃ again. Repeat this cycle 3 times. Finally, take it out and bring it to room temperature, then add 10 ml of 0.1% ascorbic acid antioxidant and maintain the pH at 5~6.

[0058] 2. Mix decanoic acid (HBD) and thymol (HBA) at a molar ratio of 1:3, stir at 60°C until a transparent liquid is obtained, and then cool to room temperature to obtain 2. hydrophobic eutectic solvent (DES). Then mix the raw material in step 1 with DES at a mass ratio of 1:5, sonicate at 25°C and 40 kHz for 10 minutes, and finally centrifuge to separate the DES phase.

[0059] 3. Add the above DES phase to the extraction vessel, introduce liquid CO2 at a flow rate of 20 L / h, and set the parameters to 40℃ and 25 MPa; insert the ultrasonic probe (40 kHz) into the extraction vessel and perform dynamic extraction for 60 min, specifically working for 1 min with a 30 s interval.

[0060] 4. Add the supercritical extract obtained in step 3 into the SCC-100 column, set the temperature gradient to 40°C at the top, 60°C at the middle, and 80°C at the bottom, the rotor speed to 3000 rpm / min, and the vacuum degree to 0.2 kPa. Extract under these conditions and collect the fractionated condensates into temporary storage bottles.

[0061] 5. The collected fractional condensate was passed through three adsorption columns. The top and middle collected liquids were passed to an adsorption column with hydrophobic zeolite ZSM-5 (silicon-to-aluminum ratio of 300, particle size of 100 mesh) as the adsorbent, and the bottom collected liquids were passed to an adsorbent of activated carbon fiber felt (specific surface area of ​​2500 m² / g). The top flow rate was 10 mL / min at 25℃, the middle flow rate was 5 mL / min at 35℃, and the bottom flow rate was 2 mL / min at 50℃. The adsorption column after complete adsorption was then desorbed. First, nitrogen gas was introduced at 10 mL / min at room temperature for 10 min to remove impurities. Then, the top was heated to 30 °C, nitrogen gas flow rate was 30 mL / min, and desorption was carried out at a constant temperature for 30 min, followed by collection in a -30 °C cold trap. The middle section was heated to 40 °C, nitrogen gas flow rate was 20 mL / min, and desorption was carried out at a constant temperature for 30 min, followed by collection in a -60 °C cold trap. The bottom was heated to 60 °C, nitrogen gas flow rate was 10 mL / min, and desorption was carried out at a constant temperature for 30 min, followed by collection in a -90 °C cold trap. Finally, the three-stage condensate was collected.

[0062] 6. Take 300 μL of each of the three-stage condensates, add 100 μL of 1 mg / mL n-heptadecane internal standard solution, shake well, and analyze by GC-MS.

[0063] Comparative Example 1 10 g of mango was selected as raw material, and it was directly extracted by soaking in 100 mL of ethanol solvent. After filtration, 900 μL of the solution was taken, 100 μL of 1 mg / mL n-heptadecane internal standard solution was added, and the solution was shaken well. The solution was then analyzed by GC-MS.

[0064] Comparative Example 2 10 g of mango was selected as raw material, 100 mL of ethanol solution was added, and the mixture was extracted by ultrasonication at 50 °C and 40 kHz for 60 min. After ultrasonication, the mixture was cooled to room temperature and filtered. 900 μL of the solution was taken, 100 μL of 1 mg / mL n-heptadecane internal standard solution was added, and the mixture was shaken well. The mixture was then analyzed by GC-MS.

[0065] The data obtained from GC-MS analysis of the examples and comparative examples are shown in Table 1.

[0066] Table 1. GC-MS Analysis Data of Volatile Compounds in Mango

[0067] As shown in Table 1, Example 1 has a higher and more accurate extraction rate of volatile substances compared to Comparative Examples 1 and 2, especially for key fruit aroma components such as terpenes (α-pinene, β-pinene, γ-terpinene, etc.) and lactones (γ-heptyl lactone, γ-octyl lactone, γ-nonyl lactone).

[0068] The reasons are as follows: Traditional organic solvent extraction in Comparative Example 1 fails to extract volatile and low-content substances, and the resulting solution is impure and toxic due to the organic solvent, causing environmental pollution. Ultrasonic-assisted extraction in Comparative Example 2 utilizes the cavitation effect of ultrasound to disrupt cell walls; however, the high temperature of ultrasound also leads to heat loss from volatile substances and easily damages their structure. Furthermore, the high temperature causes the decomposition of volatile substances, producing harmful byproducts that further affect the purity of the extracted solution. In contrast, Example 1 employs a four-stage low-temperature synergistic process, replacing traditional water-soluble DES with a novel hydrophobic DES (decanoic acid-thymol), improving the wax layer dissolution efficiency. The intermittent mode lowers the temperature, and the three-stage separation followed by adsorption-desorption, along with the graded collection of substances with different boiling points, significantly increases the extraction efficiency.

[0069] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for extracting volatile substances from fruits, characterized in that, The method includes: The fruit raw materials are crushed and then subjected to freeze-thaw cycles to obtain pre-treated fruit raw materials. The pretreated fruit raw materials were treated with a hydrophobic eutectic solvent to obtain a raw material mixture; A volatile substance extract is obtained from the raw material mixture using supercritical CO2 dynamic extraction technology, and the volatile substance extract is then separated to obtain volatile substances.

2. The method according to claim 1, characterized in that, The freeze-thaw cycle treatment of the pulverized pieces includes: The pulverized pieces are placed at a preset temperature and frozen for a preset time, then restored to room temperature. After repeating the above operation, an antioxidant is added to the crushed fruit after the last cycle to obtain the pretreated fruit raw material.

3. The method according to claim 1, characterized in that, The process of treating the pretreated fruit raw materials with a hydrophobic eutectic solvent to obtain a raw material mixture includes: A hydrophobic eutectic solvent is obtained by mixing decanoic acid and thymol or choline and lactic acid and stirring until a transparent liquid is obtained. The pretreated fruit raw material and the hydrophobic eutectic solvent are mixed and then subjected to ultrasonic and separation treatment. The separated hydrophobic eutectic solvent phase is used as the raw material mixture.

4. The method according to claim 1, characterized in that, Obtaining a volatile substance extract from the raw material mixture using supercritical CO2 dynamic extraction technology includes: loading the raw material mixture into an extraction vessel and introducing liquid carbon dioxide; inserting an ultrasonic probe into the extraction vessel and obtaining the volatile substance extract through intermittent extraction; and / or, The process of processing the volatile substance extract to obtain volatile substances includes: setting multiple different temperature zones in a rotating conical column distillation column; injecting the volatile substance extract into the rotating conical column distillation column for separation to obtain condensate corresponding to each different temperature zone; injecting the condensate of each different temperature zone into an adsorption column for adsorption; and obtaining a variety of volatile substances after desorption.

5. The method according to claim 2, characterized in that, The temperature of the pulverization process is 2~6℃; and / or, The size of the pulverized pieces is 0.5mm to 2mm; and / or, The preset temperature is -15~-20℃; and / or, The antioxidant comprises at least one of the following: ascorbic acid, sodium D-isoascorbate, butylated hydroxyanisole, and antioxidant B215; and / or, The ratio of the mass of the fruit raw material to the volume of the antioxidant is 1:1; and / or, The pH of the pretreated fruit raw material is 5-6; and / or, The preset freezing time is 5-15 minutes; and / or, The number of cycles is 2 to 4.

6. The method according to claim 3, characterized in that, The molar ratio of the decanoic acid to the thymol is 1:(2~4); and / or, The molar ratio of choline to lactate is 1:(2~4); and / or, The stirring temperature is 50~80℃; and / or, The ultrasonic treatment parameters include: ultrasonic power of 40~100KHz, ultrasonic temperature of 20~30℃, and ultrasonic treatment time of 10~30min; and / or, The mass ratio of the pretreated fruit raw material to the hydrophobic eutectic solvent is 1:(3~7).

7. The method according to claim 4, characterized in that, The process parameters for the intermittent extraction include: temperature of 30~50℃, pressure of 20~30MPa, frequency of ultrasonic probe of 30~50kHz, flow rate of liquid carbon dioxide of 15~25L / h, total extraction time of 50~70min, extraction time of a single extraction of 40~80s, and extraction interval of 20~40s.

8. The method according to claim 4, characterized in that, The rotating conical column distillation column is provided with different temperature zones at the top, middle, and bottom; wherein the top temperature is 30~50℃, the middle temperature is 50~70℃, and the bottom temperature is 70~90℃; and / or, The vacuum level of the rotating conical column distillation column is 0.1~0.5 kPa; and / or, The rotational speed of the rotating conical column is 2500~3500 rpm / min; and / or, The adsorbent in the adsorption columns corresponding to the top and middle condensates is ZSM-5 zeolite; and / or, The adsorbent in the adsorption column corresponding to the bottom condensate is activated carbon fiber felt; and / or, The process parameters for injecting top condensate into the adsorption column include: a flow rate of 8–12 mL / min and a temperature of 23–27 °C; and / or, The process parameters for injecting the central condensate into the adsorption column include: a flow rate of 3–7 mL / min and a temperature of 33–37 °C; and / or, The process parameters for injecting bottom condensate into the adsorption column include: a flow rate of 1–4 mL / min and a temperature of 48–52 °C; and / or, The desorption conditions for the top condensate include: temperature of 28–32 °C, nitrogen flow rate of 28–32 mL / min, isothermal desorption time of 28–32 min, and cold trap collection temperature of -28 to -32 °C; and / or, The desorption conditions for the central condensate include: temperature of 38–42 °C, nitrogen flow rate of 18–22 mL / min, isothermal desorption time of 28–32 min, and cold trap collection temperature of -58–-62 °C; and / or, The desorption conditions for the bottom condensate include: temperature of 58~62℃, nitrogen flow rate of 8~12mL / min, isothermal desorption time of 28~32min, and cold trap collection temperature of -88~-92℃.

9. A fruit flavoring, characterized in that, The fruit flavoring includes volatile substances obtained by any one of the methods of claims 1-8.

10. An atomizing fluid, characterized in that, The atomizing liquid includes the fruit flavoring as described in claim 9.

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