White tea aroma substance extraction method based on ultrasonic technology
Through the method of ultrasonic-assisted extraction and modified SPME fiber, the problem of insufficient adsorption capacity of white tea aroma substances by traditional solid-phase microextraction technology was solved, efficient and low-temperature extraction was achieved, and the yield and detection accuracy of white tea aroma substances were improved.
Patent Information
- Application Number
- CN202510804717.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-09-23
AI Technical Summary
Traditional solid-phase microextraction technology has insufficient adsorption capacity for white tea aroma substances, and high-temperature operation causes denaturation of heat-sensitive components, affecting the yield.
Ultrasonic technology is used to assist extraction, and SPME fiber is modified to enhance the adsorption capacity of white tea aroma substances. Low-temperature operation is used to reduce the loss of heat-sensitive components, and MIPs layer fiber that can adsorb white tea aroma substances is used.
The extraction efficiency and detection sensitivity of white tea aroma substances were improved, the loss of heat-sensitive components was reduced, and the sample pretreatment steps were simplified.
Smart Images
Figure BDA0005452243040000041
Abstract
Description
Technical Field
[0001] The invention belongs to the extraction-related technical field, and particularly relates to a method for extracting white tea aroma substances based on ultrasonic technology. Background Art
[0002] Tea aroma is a key sensory indicator for evaluating tea quality, particularly in white tea, where its unique floral aroma holds significant market value. In recent years, solid-phase microextraction (SPME) has been widely used for the extraction of aroma compounds due to its solvent-free nature, ease of operation, and high sensitivity. However, traditional SPME techniques rely on commercially available coated fibers, which have a limited adsorption capacity for a variety of volatile compounds but lack selectivity, limiting the extraction of aroma compounds from white tea. Furthermore, traditional SPME fibers struggle to efficiently enrich heat-sensitive, low-concentration aroma compounds during the extraction process. Some heat-sensitive components decompose with increasing temperature, even generating new compounds, resulting in reduced yields. Summary of the Invention
[0003] In view of the problems in the prior art that the layered fibers used in traditional solid-phase microextraction technology lack selectivity and have insufficient adsorption capacity for white tea aroma substances, and that high-temperature operation causes denaturation of some heat-sensitive components, the present invention provides a method for extracting white tea aroma substances based on ultrasonic technology. Its purpose is to improve the extraction efficiency of aroma, introduce ultrasonic technology, accelerate aroma release and enhance the mass transfer process, and develop an SPME fiber that can adsorb white tea aroma substances.
[0004] The technical solution adopted by the present invention is as follows: a method for extracting white tea aroma substances based on ultrasonic technology, comprising the following steps:
[0005] 1) Place fresh white tea leaves in a headspace bottle and equilibrate in a constant temperature water bath at 40-60°C;
[0006] 2) inserting the SPME fiber A capable of adsorbing white tea aroma substances into the headspace bottle equilibrated in step 1) and performing adsorption at 40-60° C. to obtain the SPME fiber A capable of adsorbing white tea aroma substances;
[0007] 3) The white tea leaves adsorbed in step 2) are crushed, water is added and mixed to obtain a suspension, and the SPME fiber B capable of adsorbing white tea aroma substances is inserted into the suspension for low-temperature ultrasonic extraction. After the treatment is completed, the SPME fiber B capable of adsorbing white tea aroma substances is removed;
[0008] 4) The SPME fiber A capable of adsorbing white tea aroma substances obtained in step 3) and the SPME fiber B capable of adsorbing white tea aroma substances obtained in step 4) are immersed in an ethanol solution for ultrasonic collection to obtain a white tea aroma substance extract.
[0009] The present invention carries out the entire extraction process at a lower operating temperature, effectively reducing the loss and conversion of heat-sensitive components. At the same time, the introduction of ultrasonic-assisted invasive extraction shortens the processing time, further reducing the loss of heat-sensitive components. Solid microextraction technology does not require a large amount of organic solvents, simplifying the sample pretreatment steps.
[0010] Furthermore, in step 2), the preparation method of the SPME fiber capable of adsorbing white tea aroma substances is as follows: dissolving linalool, ethylene glycol dimethacrylate, and azobisisobutyronitrile in acetonitrile, immersing the fiber substrate, letting it stand for 30 to 40 minutes, and performing a polymerization reaction. After the reaction is completed, washing it with acetonitrile solution 3 to 5 times to obtain the SPME fiber capable of adsorbing white tea aroma substances. The traditional SPME fiber is modified by adding a MIPs layer capable of absorbing white tea aroma substances to enhance the adsorption capacity of the target substance, effectively reduce the competitive adsorption of non-target substances, and improve the detection sensitivity of the target aroma component.
[0011] Furthermore, linalool, ethylene glycol dimethacrylate, and azobisisobutyronitrile are dissolved in an acetonitrile solution in a weight ratio of 1:(3-5):(18-20).
[0012] Furthermore, the SPME fiber substrate is one of stainless steel wire or quartz fiber.
[0013] Furthermore, the polymerization reaction temperature is 60-65° C., and the reaction time is 4-6 hours.
[0014] Furthermore, in step 1), the equilibration time is 10 to 30 minutes.
[0015] Furthermore, in step 2), the equilibration time is 10 to 30 minutes.
[0016] Furthermore, in step 3), the temperature of the low-temperature ultrasonic extraction is 30-40°C.
[0017] Furthermore, the time of low-temperature ultrasonic extraction is 5 to 10 minutes.
[0018] Furthermore, in step 4), the ultrasonic collection time is 10 to 15 minutes.
[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0020] 1) The present invention introduces ultrasonic-assisted invasive extraction, which shortens the processing time and further reduces the loss of heat-sensitive components. The solid microextraction technology does not require a large amount of organic solvents, simplifying the sample pretreatment steps.
[0021] 2) The present invention is carried out at a relatively low operating temperature during the entire extraction process, thereby effectively reducing the loss and conversion of heat-sensitive components.
[0022] 3) The present invention modifies the traditional SPME fiber by adding a MIPs layer that can absorb white tea aroma substances, thereby enhancing the adsorption capacity of the target substance, effectively reducing the competitive adsorption of non-target substances, and improving the detection sensitivity of the target aroma components. DETAILED DESCRIPTION
[0023] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.
[0024] Example 1
[0025] 1) Preparation of SPME fiber capable of adsorbing white tea aroma substances
[0026] Linalool, methacrylic acid, and ethylene glycol dimethacrylate were weighed in a weight ratio of 1:4:20, acetonitrile was gradually added until all solids were completely dissolved, 0.5% of the total mass of methacrylic acid and ethylene glycol dimethacrylate was added, and the mixture was stirred evenly to form a premixed solution; a quartz fiber was immersed in the prepolymerization solution, allowed to stand at 25°C for 30 minutes, the quartz fiber was taken out, and a polymerization reaction was carried out in an oven at 60°C for 6 hours, and the fiber was repeatedly washed with a large amount of acetonitrile solution. When linalool was no longer detected in the eluent, the washing was stopped, and the fiber was allowed to stand and dry to obtain an SPME fiber capable of adsorbing white tea aroma substances.
[0027] 2) Extraction
[0028] Fresh white tea leaves were placed in a sealed headspace bottle and equilibrated in a constant temperature water bath at 45°C for 25 minutes. The SPME fiber A prepared in step 1) capable of adsorbing white tea aroma substances was inserted into the headspace bottle and adsorbed at 45°C for 25 minutes. The white tea leaves were taken out and crushed, and deionized water was added to form a suspension. The suspension was treated in an ultrasonic water bath at 30°C for 6 minutes. At the same time, the SPME fiber B capable of adsorbing white tea aroma substances was inserted into the suspension for extraction.
[0029] 3) Desorption
[0030] The SPME fiber A capable of adsorbing white tea aroma substances and the SPME fiber B capable of adsorbing white tea aroma substances extracted in step 2) are immersed in an ethanol solution, sealed and ultrasonically treated for 5 minutes, and the SPME fiber A capable of adsorbing white tea aroma substances and the SPME fiber B capable of adsorbing white tea aroma substances are taken out to obtain a white tea aroma substance extract.
[0031] 4) Detection
[0032] The linalool content of the white tea aroma substance extract prepared in step 3) was detected, and the extraction amount and recovery rate were calculated.
[0033] Comparative Example 1
[0034] The only difference between this comparative example and Example 1 is that, in this comparative example, normal quartz fiber is used instead of the SPME fiber capable of adsorbing white tea aroma substances, and the rest of the process is the same as that of Example 1.
[0035] Table 1 Effect of modified fiber on the extraction of aroma compounds from white tea
[0036] Fiber Type Linalool content% Average extraction volume (μg / ml) Recovery rate (%) Example 1 MIPs-coated SPME fibers 85 4.8 96 Comparative Example 1 Quartz fiber 60 3.5 70
[0037] By comparison with the data in Table 1, it can be concluded that MIPs coating of quartz fiber increases the selectivity of white tea aroma substances, improves the recovery rate, effectively eliminates the interference of non-target substances, and improves the purity of the target compound.
[0038] Comparative Example 2
[0039] The only difference between this comparative example and Example 1 is that in this comparative example, the temperature of the constant temperature water bath in step 2) is 70° C., and the rest of the process is the same as in Example 1.
[0040] Comparative Example 3
[0041] The only difference between this comparative example and Example 1 is that in this comparative example, the temperature of the constant temperature water bath in step 2) is 25° C., and the rest of the process is the same as in Example 1.
[0042] Table 2 Effect of water bath equilibration time on aroma substances in white tea
[0043]
[0044] From the data in Table 2, it can be concluded that when the water bath equilibrium temperature is too high or too low, the content of linalool, the aroma substance of white tea, which is finally collected, will decrease, thereby reducing the recovery rate. The reasons are speculated to be: when the equilibrium temperature is too high, the heat-sensitive components will be denatured, resulting in a decrease in product purity and yield; when the equilibrium temperature is too low, the volatile substances cannot diffuse, resulting in the inability to effectively collect and extract.
[0045] Example 2
[0046] 1) Preparation of SPME fiber capable of adsorbing white tea aroma substances
[0047] Linalool, methacrylic acid, and ethylene glycol dimethacrylate were weighed in a weight ratio of 1:3:18, acetonitrile was gradually added until all solids were completely dissolved, 1% of the total mass of methacrylic acid and ethylene glycol dimethacrylate was added, and the mixture was stirred evenly to form a premixed solution; a stainless steel wire was immersed in the prepolymerization solution, allowed to stand at 25°C for 30 minutes, the stainless steel wire was removed, and a polymerization reaction was carried out in an oven at 60°C for 6 hours, and the wire was repeatedly washed with a large amount of acetonitrile solution. When linalool was no longer detected in the eluent, the washing was stopped, and the wire was allowed to stand and dry to obtain an SPME fiber capable of adsorbing white tea aroma substances.
[0048] 2) Extraction
[0049] Fresh white tea leaves were placed in a sealed headspace bottle and equilibrated in a constant temperature water bath at 50°C for 25 minutes. The SPME fiber A prepared in step 1) capable of adsorbing white tea aroma substances was inserted into the headspace bottle and adsorbed at 50°C for 25 minutes. The white tea leaves were taken out and crushed, and deionized water was added to form a suspension. The suspension was treated in an ultrasonic water bath at 30°C for 6 minutes. At the same time, the SPME fiber B capable of adsorbing white tea aroma substances was inserted into the suspension for extraction.
[0050] 3) Desorption
[0051] The SPME fiber A capable of adsorbing white tea aroma substances and the SPME fiber B capable of adsorbing white tea aroma substances extracted in step 2) are immersed in an ethanol solution, sealed and ultrasonically treated for 5 minutes, and the SPME fiber A capable of adsorbing white tea aroma substances and the SPME fiber B capable of adsorbing white tea aroma substances are taken out to obtain a white tea aroma substance extract.
[0052] 4) Detection
[0053] The white tea aroma substance extract prepared in step 3) is tested by GC-MS and HPLC.
[0054] The above-described embodiments merely represent specific implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the technical concept of the present application, and all such variations and improvements fall within the scope of protection of the present application.
Claims
1. A method for extracting white tea aroma substances based on ultrasonic technology, characterized in that: The following steps are involved: 1) Place fresh white tea leaves in a headspace bottle and equilibrate in a constant temperature water bath at 40-60°C; 2) inserting the SPME fiber A capable of adsorbing white tea aroma substances into the headspace bottle equilibrated in step 1) and performing adsorption at 40-60° C. to obtain the SPME fiber A capable of adsorbing white tea aroma substances; 3) The white tea leaves adsorbed in step 2) are crushed, water is added and mixed to obtain a suspension, and the SPME fiber B capable of adsorbing white tea aroma substances is inserted into the suspension for low-temperature ultrasonic extraction. After the treatment is completed, the SPME fiber B capable of adsorbing white tea aroma substances is removed; 4) The SPME fiber A capable of adsorbing white tea aroma substances obtained in step 3) and the SPME fiber B capable of adsorbing white tea aroma substances obtained in step 4) are immersed in an ethanol solution for ultrasonic collection to obtain a white tea aroma substance extract.
2. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 1, characterized in that: In step 2), the preparation method of the SPME fiber capable of adsorbing white tea aroma substances is as follows: dissolving linalool, ethylene glycol dimethacrylate, and azobisisobutyronitrile in acetonitrile, immersing the fiber substrate, and allowing it to stand for 30 to 40 minutes to carry out a polymerization reaction. After the reaction is completed, washing it with acetonitrile solution 3 to 5 times to obtain the SPME fiber capable of adsorbing white tea aroma substances.
3. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 2, characterized in that: Linalool, ethylene glycol dimethacrylate and azobisisobutyronitrile are dissolved in an acetonitrile solution in a weight ratio of 1:(3-5):(18-20).
4. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 3, characterized in that: The SPME fiber substrate is either stainless steel wire or quartz fiber.
5. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 2 or 4, characterized in that: The polymerization temperature is 60-65° C., and the reaction time is 4-6 hours.
6. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 1, characterized in that: In step 1), the equilibration time is 10 to 30 minutes.
7. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 1, characterized in that: In step 2), the equilibration time is 10 to 30 minutes.
8. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 1, characterized in that: In step 3), the temperature of low-temperature ultrasonic extraction is 30-40°C.
9. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 8, characterized in that: The time of low-temperature ultrasonic extraction is 5 to 10 minutes.
10. The method for extracting white tea aroma substances based on ultrasonic technology according to claim 1, characterized in that: In step 4), the ultrasonic collection time is 10 to 15 minutes.