Method for detecting authenticity and content of camellia oleosa seed oil based on tetrahydro-6-tridecyl-2H-pyran-2-one

Abstract

The invention relates to the technical field of quality control of camellia oleosa seed oil, and discloses a method for detecting authenticity and content of camellia oleosa seed oil based on characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one, and the method comprises the following steps: analyzing existence and content of tetrahydro-6-tridecyl-2H-pyran-2-one in vegetable oil; performing qualitative judgment and quantitative analysis on the camellia oleosa seed oil; the method comprises the following steps: extracting, purifying and measuring tetrahydro-6-tridecyl-2H-pyran-2-ketone in the vegetable oil by adopting the technologies of dissolving the vegetable oil with n-hexane, degreasing with a sulfonation method, deacidifying and purifying with a sodium sulfate aqueous solution, detecting with a gas chromatograph-mass spectrometer and the like, and determining whether the tetrahydro-6-tridecyl-2H-pyran-2-ketone exists in the vegetable oil or not and the content of the tetrahydro-6-tridecyl-2H-pyran-2-ketone in the vegetable oil, so as to determine the content of the tetrahydro-6-tridecyl-2H-pyran-2-ketone in the vegetable oil. The authenticity and the content of the camellia oleosa seed oil are indicated. The method is simple and feasible in technology and good in reproducibility, realizes accurate identification and content analysis of the camellia oleosa seed oil, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the quality control technology field of oil tea seed oil, and in particular to a method for identifying and quantitatively detecting the authenticity and adulteration content of oil tea seed oil based on a characteristic marker tetrahydro-6-tridecyl-2H-pyran-2-one. BACKGROUND

[0002] Oil tea is rich in sterols, tocopherols and squalene and other physiological active substances, and unsaturated fatty acids account for as high as 90%. The antioxidant capacity is 60 times that of ordinary oil, and it is known as "Oriental olive oil" and "treasure of oil". The high market price (generally higher than 100 yuan / kg) induces adulteration chaos.

[0003] Although the national standards GB 5009.168-2016 "National food safety standard Determination of fatty acids in food" and GB11765-2018 "Oil tea seed oil" take the fatty acid composition (such as 74%~87% of oleic acid) and refractive index as the core discriminant index, there are two major bottlenecks: one is the wide index, and the other is the lagging method. The method is urgently needed to establish a more accurate identification technology system.

[0004] The current plant oil identification technology mainly falls into three categories: component analysis method (such as gas chromatography GC, liquid chromatography HPLC determination of fatty acids / sterols) relies on the easily degradable active substances in the first pressing crude oil; spectral rapid detection (including infrared FTIR, nuclear magnetic resonance LF-NMR and ultraviolet spectrum) is insufficient in specificity due to the attenuation of functional group signals after refining; combined technology and rapid detection (such as GC-MS, carbon isotope ratio mass spectrometry IRMS, colorimetric method patent CN101893553B, electronic nose / tongue) cannot distinguish the residual trace markers in refined oil. The fundamental contradiction lies in: 90% of the oil tea seed oil on the market is refined oil, and after the degumming, deacidification, bleaching and 200~260°C high temperature deodorization process, the characteristic substances (tocopherols, squalene, etc.) of the first pressing oil are lost by more than 70%, volatile aldehydes and ketones are removed by distillation, and the structure of sterols is destroyed by high temperature, resulting in the "characteristic target" relied on by traditional methods in the finished oil. The content is extremely small or disappears, and the detection sensitivity and accuracy are seriously insufficient.

[0005] Therefore, the present inventors found that tetrahydro-6-tridecyl-2H-pyran-2-one has irreplaceable technical advantages in view of the industry pain point of the scarcity of characteristic substances in refined oil: first, extreme stability: the molecule contains a six-membered lactone ring and a 13-carbon alkyl chain, with a boiling point of 385°C, resistant to high temperature and high pressure in the whole refining process; second, absolute specificity: only detected in oil tea seed oil, no detection in common adulterated oils such as soybean oil, rapeseed oil, corn oil and palm oil; at the same time, traceability is strong, the detection limit of GC-MS is 0.01 mg / kg, which can quantify 5%~100% adulteration gradient, providing a reliable basis for the authenticity identification and adulteration quantification of oil tea seed oil, and filling the gap in the existing technology. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application aims to provide a method for determining the authenticity and content of oil-tea camellia seed oil using tetrahydro-6-tridecyl-2H-pyran-2-one as an index, to solve the technical problem of lack of analysis of oil-tea camellia seed oil content in the finished product "oil-tea camellia seed oil" in the prior art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solution: A method for detecting the authenticity and content of oil-tea camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one, comprising the following steps: A. Mix the plant oil sample uniformly, and weigh the plant oil sample into a test tube with a plug; B. Add n-hexane to dissolve the plant oil in the test tube containing the plant oil sample, cover the plug, and mix uniformly at high speed; C. Add concentrated sulfuric acid to the mixed test tube, cover the plug, and mix uniformly at high speed; D. Place the vortexed test tube on a test tube rack for static treatment and layering to remove fatty acids, pigments and impurities in the plant oil; E. Absorb the supernatant (n-hexane layer) after static treatment into another test tube with a plug, add sodium sulfate aqueous solution, cover the plug, and vortex at high speed; F. Place the vortexed test tube on a test tube rack for static treatment and layering to remove residual sulfuric acid in the n-hexane extract; G. Absorb 1 ml of the supernatant (n-hexane layer) after static treatment in F, pass it through a microporous filter membrane, and then put it into a sample bottle, and then detect and analyze it using a gas chromatograph-mass spectrometer; H. Establish an oil-tea camellia seed oil percentage content calibration curve: weigh the self-made and pressed oil-tea camellia seed oil, supplement the plant oil to 1g if it is less than 1g, prepare oil-tea camellia seed oil with mass fractions of 0, 10%, 30%, 50%, 70%, and 100%, respectively, analyze them simultaneously according to steps B-G, and establish a calibration curve of oil-tea camellia seed oil mass percentage concentration using the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one as the ordinate and the mass percentage of oil-tea camellia seed oil as the abscissa; I. Verify whether the plant oil contains oil-tea camellia seed oil by detecting whether tetrahydro-6-tridecyl-2H-pyran-2-one is detected, and calculate the mass percentage concentration of oil-tea camellia seed oil in the sample by bringing the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one into the calibration curve established in step H.

[0008] The present application has systematically screened the characteristic components of oil-tea camellia seed oil products of different sources, oil extraction methods and processing degrees, and obtained a relatively stable six-membered ring lactone, i.e. "tetrahydro-6-tridecyl-2H-pyran-2-one" (C 18 H34 O2), the mass spectrum of which is shown in Figure 1. Figure 1 The component only exists in oil-tea camellia seed oil among common edible vegetable oils. Through determination on 20 oil-tea camellia seed oils processed in different ways, it is found that the content deviation of tetrahydro-6-tridecyl-2H-pyran-2-one is only 5%, and the content of tetrahydro-6-tridecyl-2H-pyran-2-one is stable in crude oil and refined oil of oil-tea camellia seed oil. The present application qualitatively determines and quantitatively analyzes oil-tea camellia seed oil by analyzing the existence and content of tetrahydro-6-tridecyl-2H-pyran-2-one in vegetable oil.

[0009] Meanwhile, vegetable oil is a kind of oil and fat mainly composed of fatty acid glycerides, rich in vitamins, pigments, proteins, terpenes and other substances, and the components are extremely complex. If the pretreatment is not ideal, it will directly affect the detection results of tetrahydro-6-tridecyl-2H-pyran-2-one by subsequent instruments. The degreasing treatment is extremely critical. In the present method, sulfonation method is used for degreasing and impurity removal, and sodium sulfate aqueous solution is used for deacidification and purification, so as to achieve ideal purification effect.

[0010] As preferred, in step A, 0.5-1.5 g of the vegetable oil sample is weighed in a 25 ml test tube with a plug.

[0011] As preferred, in step B, the n-hexane is chromatographically pure n-hexane, 10 ml of n-hexane is added, and the vortex time is 10-30 s, preferably 30 s.

[0012] As preferred, in step C, the concentrated sulfuric acid is premium grade pure concentrated sulfuric acid, and the volume is 3-5 ml, preferably 3 ml, and the plug is covered and vortexed at high speed for 20 s.

[0013] As preferred, in steps D and F, the standing and layering time is 10-20 min, preferably 15 min.

[0014] As preferred, in step E, the volume of the supernatant is 3-5 ml, preferably 5 ml; the added sodium sulfate aqueous solution is 10 ml of 2% mass concentration of anhydrous sodium sulfate aqueous solution, and vortexed at high speed for 20 s.

[0015] As preferred, in step G, 1-2 ml of the supernatant is taken, preferably 1 ml; the pore size of the microporous filter membrane is 0.25 μm.

[0016] As preferred, in step H, the supplementary vegetable oil is soybean oil.

[0017] The present application has the following technical effects due to the adoption of the above technical solutions: The present application is based on the fact that tetrahydro-6-tridecyl-2H-pyran-2-one only exists in camellia seed oil among common edible vegetable oils, and the content of tetrahydro-6-tridecyl-2H-pyran-2-one in camellia seed oil of different sources and processing stages is relatively stable. By analyzing the presence or absence and content of tetrahydro-6-tridecyl-2H-pyran-2-one in vegetable oil, qualitative determination and quantitative analysis of camellia seed oil are carried out. At the same time, techniques such as sulfonation method for degreasing and impurity removal, sodium sulfate aqueous solution for deacidification and purification, and gas chromatography-mass spectrometry for detection are used to extract, purify and determine tetrahydro-6-tridecyl-2H-pyran-2-one in vegetable oil. The presence or absence and content of tetrahydro-6-tridecyl-2H-pyran-2-one in vegetable oil indicate the authenticity and content of camellia seed oil. The method is simple and feasible, has good reproducibility, can realize accurate identification and content analysis of camellia seed oil, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the mass spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one.

[0019] Figure 2 It is the total ion current chromatogram of the sample of Example 1 (containing the "tetrahydro-6-tridecyl-2H-pyran-2-one" part).

[0020] Figure 3 It is the mass spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample of Example 1 (the upper half is the sample spectrum, and the lower half is the spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in NIST20 spectrum library).

[0021] Figure 4 It is the selected ion spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample of Example 1.

[0022] Figure 5 It is the total ion current chromatogram of the sample of Example 2 (containing the "tetrahydro-6-tridecyl-2H-pyran-2-one" part).

[0023] Figure 6 It is the mass spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample of Example 2 (the upper half is the sample spectrum, and the lower half is the spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in NIST20 spectrum library).

[0024] Figure 7 It is the selected ion spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample of Example 2.

[0025] Figure 8Total ion chromatogram of the sample of Example 3 (the peak position of "tetrahydro-6-tridecyl-2H-pyran-2-one" should be present).

[0026] Figure 9 Selected ion mass chromatogram of the sample of Example 3 at the peak position of tetrahydro-6-tridecyl-2H-pyran-2-one that should be present.

[0027] Figure 10 Selected ion chromatogram of the sample of Example 3 at the time period of the peak position of tetrahydro-6-tridecyl-2H-pyran-2-one that should be present. DETAILED DESCRIPTION

[0028] The application will be further described in detail below with reference to the accompanying drawings and examples.

[0029] Example 1 A method for detecting the authenticity and content of oil-tea camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one, comprising the following steps: A. Mix the plant oil sample uniformly, and take 1.00 g of the plant oil sample in a 25 ml test tube with a plug; B. Add 10 ml of chromatographically pure n-hexane to the test tube containing the plant oil sample, and vortex at high speed for 30 s; C. Add 3 ml of high-purity concentrated sulfuric acid to the mixed test tube, cover the plug, and vortex at high speed for 20 s; D. Place the vortexed test tube on a test tube rack and stand for 15 min, and separate the layers to remove the fatty acids, pigments and impurities in the plant oil; E. Take 5 ml of the supernatant (n-hexane layer) after standing in another 25 ml test tube with a plug, and add 10 ml of 2% mass concentration of anhydrous sodium sulfate aqueous solution, and vortex at high speed for 20 s; F. Place the vortexed test tube on a test tube rack and stand for 15 min, and separate the layers to remove the residual sulfuric acid in the n-hexane extract; G. Take 1 ml of the supernatant (n-hexane layer) after standing in F, pass it through a 0.25 μm microporous filter membrane, and then put it into a sample bottle for detection and analysis by a gas chromatograph-mass spectrometer; H. Establish a calibration curve for the percentage content of oil-tea camellia seed oil: take self-made, pressed oil-tea camellia seed oil, and supplement with soybean oil to 1 g if the weight is less than 1 g, and prepare oil-tea camellia seed oil with mass fractions of 0, 10%, 30%, 50%, 70%, and 100%, respectively, and analyze them simultaneously according to steps B~G, and establish a calibration curve for the mass percentage concentration of oil-tea camellia seed oil with the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one as the ordinate and the mass percentage of oil-tea camellia seed oil as the abscissa; I. The sample was verified for the presence of oil tea seed oil by detecting tetradecyl-6-tridecyl-2H-pyran-2-one. The peak area of tetradecyl-6-tridecyl-2H-pyran-2-one was used to calculate the mass percentage of oil tea seed oil in the sample according to the calibration curve established in step H.

[0030] Chromatographic conditions of GC-MS: Inlet: 250℃; Injection volume: 1 μl, splitless injection; Chromatographic column: HP-5MS 5% Phenyl Methyl Silox (30 m x 0.25 mm, 0.25 μm); Carrier gas: He, flow rate 1 ml / min; Programmed temperature: 50℃ for 0.5 min, 5℃ / min to 250℃ for 5 min, 10℃ / min to 280℃ for 1 min; Auxiliary heating zone (MSD transfer line): 280℃; Mass spectrometry acquisition mode: full scan (scan), mass number 50.0~500, for qualitative analysis; selected ion scan (sim), mass number 99, residence time 100 ms, mass number 114, residence time 50 ms, mass number 264, residence time 50 ms, for quantitative analysis; Solvent delay: 3.0 min; Ion source: 230℃; MS quadrupole rod: 150℃.

[0031] Detection results: Figure 2 、 Figure 3 、 Figure 4 The total ion chromatogram of the sample (containing the "tetradecyl-6-tridecyl-2H-pyran-2-one" part), the mass spectrum of tetradecyl-6-tridecyl-2H-pyran-2-one in the sample, and the selected ion spectrum of tetradecyl-6-tridecyl-2H-pyran-2-one in the sample are shown in the following figures, respectively: Figure 2 、 Figure 3 The results show that the sample contains oil tea seed oil, Figure 4 The peak area of the quantitative ion (99) was measured to be 1695465. According to the calibration curve (Y=17011x+4162, r2=0.9995) obtained in step H, the content of oil tea seed oil in the sample was calculated to be 99.4%.

[0032] Conclusion: The content of oil tea seed oil in the sample is 99.4%±5%, which is pure oil tea seed oil.

[0033] Example 2 A method for detecting the authenticity and content of oil-tea camellia seed oil based on tetrahydro-6-tridecyl-2H-pyran-2-one characteristic, comprising the following steps: A. Mix the vegetable oil sample uniformly, and weigh 1.00 g of the vegetable oil sample in a 25 ml test tube with a plug; B. Add 10 ml of chromatographically pure n-hexane to the test tube containing the vegetable oil sample, and vortex at high speed for 30 s; C. Add 3 ml of high-purity concentrated sulfuric acid to the mixed test tube, cover the plug, and vortex at high speed for 20 s; D. Place the vortexed test tube on a test tube rack and stand for 15 min, and remove the fatty acids, pigments and impurities in the vegetable oil after layering; E. Take 5 ml of the supernatant (n-hexane layer) after standing in another 25 ml test tube with a plug, and add 10 ml of 2% mass concentration of anhydrous sodium sulfate aqueous solution, and vortex at high speed for 20 s; F. Place the vortexed test tube on a test tube rack and stand for 15 min, and remove the residual sulfuric acid in the n-hexane extract after layering; G. Take 1 ml of the supernatant (n-hexane layer) after standing in F, pass through a 0.25 μm microporous filter membrane, and then put it into a sample bottle, and then detect and analyze it with a gas chromatograph-mass spectrometer; H. Establish the oil-tea camellia seed oil percentage content calibration curve: weigh the self-made and pressed oil-tea camellia seed oil, and supplement it with soybean oil to 1 g if it is less than 1 g, and prepare oil-tea camellia seed oil with mass fractions of 0, 10%, 30%, 50%, 70%, and 100%, respectively, and analyze them simultaneously according to steps B-G, and establish the calibration curve of the oil-tea camellia seed oil mass percentage concentration with the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one as the ordinate and the oil-tea camellia seed oil mass percentage as the abscissa; I. Whether tetrahydro-6-tridecyl-2H-pyran-2-one is detected in the sample verifies whether the vegetable oil contains oil-tea camellia seed oil, and the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one is brought into the calibration curve established in step H to calculate the mass percentage concentration of oil-tea camellia seed oil in the sample.

[0034] Gas chromatograph-mass spectrometer chromatographic conditions: Injection port: 250℃; Injection volume: 1 μl, no split injection; Chromatographic column: HP-5MS 5% Phenyl Methyl Silox (30 m x 0.25 mm, 0.25 μm); Carrier gas: He, flow rate 1 ml / min; Programmed temperature rise: 50℃ for 0.5 min, 5℃ / min to 250℃ for 5 min, 10℃ / min to 280℃ for 1 min; Auxiliary heating zone (MSD transfer line): 280 °C; Mass spectrometry acquisition mode: full scan (scan) for qualitative analysis, mass number 50.0~500; selected ion scan (sim) for quantitative analysis, mass number 99, residence time 100 ms, mass number 114, residence time 50 ms, mass number 264, residence time 50 ms; Solvent delay: 3.0 min; Ion source: 230 °C; MS quadrupole rod: 150 °C.

[0035] Detection results: Figure 5 、 Figure 6 、 Figure 7 respectively are the total ion chromatogram of the sample (containing "tetrahydro-6-tridecyl-2H-pyran-2-one" part), the mass spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample, and the selected ion spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample; Figure 5 、 Figure 6 It is shown that the sample contains oil tea seed oil, Figure 7 The peak area of the quantitative ion (99) is measured as 502147, and the calibration curve (Y=17011x+4162, r2=0.9995) obtained by entering the H step is used to calculate that the content of oil tea seed oil in the sample is 29.3%.

[0036] Conclusion: The content of oil tea seed oil in the sample is 29.3%±5%, and other oils are doped.

[0037] Example 3 A method for detecting the authenticity and content of oil tea seed oil based on tetrahydro-6-tridecyl-2H-pyran-2-one characteristics, comprising the following steps: A. Mix the plant oil sample uniformly, and take 1.00 g of the plant oil sample in a 25 ml test tube with a plug; B. Add 10 ml of chromatographically pure n-hexane to the test tube containing the plant oil sample, and vortex at high speed for 30 s; C. Add 3 ml of high-purity concentrated sulfuric acid to the mixed test tube, cover the plug, and vortex at high speed for 20 s; D. Place the vortexed test tube on the test tube rack and stand for 15 min, and remove the fatty acids, pigments and impurities in the plant oil after layering; E. Take 5 ml of the supernatant (n-hexane layer) after standing in another 25 ml test tube with a plug, and add 10 ml of 2% mass concentration of anhydrous sodium sulfate aqueous solution, and vortex at high speed for 20 s; F. Place the vortexed test tube on the test tube rack for 15 min of standing treatment, and wait for stratification to remove residual sulfuric acid in the n-hexane extract; G. Absorb 1 ml of the supernatant (n-hexane layer) of F, pass it through a 0.25 μm microporous filter, and then put it into a sample bottle for detection and analysis by the gas chromatograph-mass spectrometer; H. Establish a calibration curve for the percentage content of oil tea seed oil: weigh the self-made and pressed oil tea seed oil, supplement it with soybean oil to 1 g if it is less than 1 g, prepare oil tea seed oil with mass fractions of 0, 10%, 30%, 50%, 70%, and 100% respectively, and analyze them simultaneously according to steps B-G, take the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one as the ordinate, and take the mass percentage of oil tea seed oil as the abscissa to establish a calibration curve for the mass percentage concentration of oil tea seed oil; I. Verify whether the plant oil contains oil tea seed oil by detecting whether tetrahydro-6-tridecyl-2H-pyran-2-one is detected in the sample, and calculate the mass percentage concentration of oil tea seed oil in the sample by taking the peak area of tetrahydro-6-tridecyl-2H-pyran-2-one into the calibration curve established in step H.

[0038] Chromatographic conditions of the gas chromatograph-mass spectrometer: Inlet: 250℃; Injection volume: 1 μl, no split injection; Chromatographic column: HP-5MS 5% Phenyl Methyl Silox (30 m x 0.25 mm, 0.25 μm); Carrier gas: He, flow rate 1 ml / min; Programmed temperature: 50℃ for 0.5 min, 5℃ / min to 250℃ for 5 min, 10℃ / min to 280℃ for 1 min; Auxiliary heating zone (MSD transfer line): 280℃; Mass spectrometry acquisition mode: full scan (scan), mass number 50.0~500, for qualitative analysis; selected ion scan (sim), mass number 99, residence time 100 ms, mass number 114, residence time 50 ms, mass number 264, residence time 50 ms, for quantitative analysis; Solvent delay: 3.0 min; Ion source: 230℃; MS quadrupole rod: 150℃.

[0039] Detection results: Figure 8 , Figure 9 , Figure 10 respectively are the total ion chromatogram of the sample (containing the peak position of “tetrahydro-6-tridecyl-2H-pyran-2-one”) and the mass spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one; Figure 9The selected ion mass spectrum of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample of Example 3 and the selected ion chromatogram of the time period of the peak position of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample; Figure 8 、 Figure 9 、 Figure 10 All show that "tetrahydro-6-tridecyl-2H-pyran-2-one" is not detected in the sample.

[0040] Conclusion: The sample is not oil-tea camellia seed oil.

[0041] The above merely illustrates the specific embodiments of the present application, but the technical features of the present application are not limited to this. Any person skilled in the art in the field of the present application can make equivalent changes and modifications within the scope of the patent application of the present application, which are all covered in the patent scope of the present application.

Claims

1. A method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one, characterized in that, Includes the following steps: A. Mix the vegetable oil sample thoroughly, and weigh out a portion of the vegetable oil sample and add it to a stoppered test tube; B. Add n-hexane to the test tube containing the vegetable oil sample to dissolve the vegetable oil, then stopper the tube and vortex at high speed to mix thoroughly. C. Add concentrated sulfuric acid to the mixed test tube, stopper it, and vortex at high speed to mix. D. Place the vortexed test tubes on a test tube rack for static treatment and layering to remove fatty acids, pigments and impurities from the vegetable oil; E. Transfer the supernatant after settling into another stoppered test tube, add sodium sulfate aqueous solution, stopper and vortex at high speed; F. Place the vortexed test tubes on a test tube rack for static treatment and layering to remove residual sulfuric acid from the hexane extract; G. Take 1 ml of the supernatant from F after it has been allowed to stand, filter it through a microporous membrane and then put it into a sample vial for analysis by gas chromatography-mass spectrometry. H. Establish a calibration curve for the percentage content of camellia seed oil: Weigh the self-made and pressed camellia seed oil, and supplement with vegetable oil to make up to 1g if less than 1g, to obtain camellia seed oil mass fractions of 0%, 10%, 30%, 50%, 70%, and 100%, respectively. Analyze simultaneously according to steps B to G. Establish a calibration curve for the mass percentage concentration of camellia seed oil with the peak area of ​​tetrahydro-6-tridecyl-2H-pyran-2-one as the ordinate and the mass percentage of camellia seed oil as the abscissa. I. The presence of tetrahydro-6-tridecyl-2H-pyran-2-one in the sample is used to verify whether the vegetable oil contains camellia seed oil. The peak area of ​​tetrahydro-6-tridecyl-2H-pyran-2-one is used to input the calibration curve established in step H to calculate the mass percentage concentration of camellia seed oil in the sample.

2. The method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to claim 1, characterized in that, In step A, weigh 0.5~1.5g of vegetable oil sample into a 25ml stoppered test tube, preferably weighing 1.00g of vegetable oil sample.

3. The method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to claim 1, characterized in that, In step B, the n-hexane is chromatographically pure n-hexane. 10 ml of n-hexane is added, and the vortexing time is 10-30 s, preferably 30 s.

4. The method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to claim 1, characterized in that, Step C: Add concentrated sulfuric acid (superior purity) in a volume of 3-5 ml, preferably 3 ml, and then stopper the container and vortex at high speed for 20 seconds.

5. The method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to claim 1, characterized in that, The settling time for steps D and F is 10-20 minutes, preferably 15 minutes.

6. The method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to claim 1, characterized in that, In step E, the volume of the supernatant is 3-5 ml, preferably 5 ml; 10 ml of anhydrous sodium sulfate aqueous solution with a mass concentration of 2% is added, and the mixture is vortexed at high speed for 20 seconds.

7. The method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to claim 1, characterized in that, In step G, 1-2 ml of the supernatant is taken, preferably 1 ml; the pore size of the microporous filter membrane is 0.25 μm.

8. A method for detecting the authenticity and content of camellia seed oil based on the characteristics of tetrahydro-6-tridecyl-2H-pyran-2-one according to any one of claims 1-7, characterized in that, The vegetable oil added in step H is soybean oil.

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