Quantitative detection method for carbonyl compounds in roasted mutton

Abstract

The invention discloses a quantitative detection method for carbonyl compounds in roasted mutton, and belongs to the technical field of meat flavor substance detection. According to the method, 18 carbonyl compounds in the roasted mutton are quantitatively detected at the same time, solid-phase microextraction is firstly adopted for derivation on fibers, and then GC-MS / MS is combined for quantitative detection of the 18 carbonyl compounds at the same time. According to the method, an internal standard curve method is adopted, and an internal standard curve is configured in a roasted mutton odorless matrix system. The method comprises the following steps: respectively weighing blank reagent water, glyceryl triacetate and the matrix without the target compound in the meat product to prepare the odorless matrix for the meat product, wherein the blank reagent water, the glyceryl triacetate and the matrix without the target compound in the meat product are respectively weighed; the method is accurate in quantification, high in sensitivity and low in detection limit, and can be widely applied to efficient and sensitive detection of carbonyl compounds in meat products.

Description

Technical Field

[0001] The invention relates to the field of meat flavor substance detection, and more specifically to a quantitative detection method for carbonyl compounds in roasted mutton. Background Art

[0002] Roasted lamb, as a classic in the history of Chinese barbecue, is not only a popular delicacy among consumers, but also a symbol of Chinese barbecue culture. It has even gradually become popular among the Z generation consumer group as a cultural symbol. Volatile flavor substances are the basis of the aroma characteristics of roasted lamb, so they have always been the focus of research. Volatile carbonyl compounds are an important component of volatile flavor substances. They mainly present ester aroma and fresh aroma in roasted lamb, which has a great influence on the aroma of roasted lamb. It is important to accurately identify and quantify them.

[0003] Odorless matrix is ​​crucial for the study of flavor substances in meat products. Whether it is sensory omics or quantitative analysis of flavor substances, it is important whether the prepared odorless matrix can restore the sample matrix and the matrix effect produced by the matrix. At present, the most widely used method for preparing odorless matrix in meat products is to use organic solvents to wash away the target compounds, and then freeze-dry to obtain the odorless matrix of meat products. This method has promoted the progress of flavor substance analysis technology, but ignores the matrix effect produced by the water and fat content in the sample. Therefore, the matrix effect produced by the sample content corresponding to the same content of matrix has a large deviation, which makes the quantification inaccurate.

[0004] The most widely used methods for determining carbonyl compounds include gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC) and spectrophotometry. However, in general, the sensitivity and selectivity of the instrument are not enough, so pretreatment methods are needed. For example, solid phase microextraction (SPME), solvent-assisted flavor evaporation (SAFE), stir bar sorptive extraction (SBSE), etc. These technologies have promoted the advancement of meat flavor chemical component detection technology. It has played a very important role in the study of meat flavor.

[0005] Carbonyl compounds are the key aroma attributes of the ester flavor and fresh flavor of roasted lamb, and their accurate qualitative and quantitative determination is important. The SAFE method is complicated to operate, carbonyl compounds are volatile, the recovery rate is low, and the target compounds are easily masked by solvent peaks during the separation process. The SBSE method is not suitable for meat sample research. Compared with other pretreatment methods, SPME integrates sample collection, extraction, concentration and injection, and can avoid fiber contact with samples to cause contamination and damage to the fiber, and has many advantages. However, due to the high volatility and activity of carbonyl compounds, and they usually exist in trace forms, and the meat product matrix is ​​complex, the mass-to-charge ratio of low molecular weight carbonyl compounds is below 100, the chromatographic separation, the detectability of mass spectrometry fragments is small, the background interference is large, the method sensitivity is low, the detection limit and the quantification limit are high, and for carbonyl compounds with low flavor thresholds, they cannot be detected or cannot be accurately quantified after detection. Therefore, it is necessary to develop a quantitative detection method for carbonyl compounds with high sensitivity, low detection limit and low quantification limit for complex meat product matrices. Therefore, how to overcome the shortcomings of the existing technology is an urgent problem to be solved in the field of meat detection technology. Summary of the invention

[0006] The purpose of the present invention is to solve the deficiencies of the prior art, provide a method for quantitatively detecting carbonyl compounds in roasted mutton based on a fiber-based derivatization solid phase microextraction method, and provide a method for preparing a set of odorless matrix of meat products in the quantification of target objects. The quantitative detection method has simple sample pretreatment and does not involve organic solvents. After derivatization, chromatographic separation and detectability of mass spectrometry fragments can be improved, background interference can be reduced, the sensitivity of carbonyl compound detection can be improved, the detection limit and the quantification limit can be reduced, and the odorless matrix of meat products can better reduce the sample matrix, the quantification is accurate, and it is easy to promote and use.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A quantitative detection method for carbonyl compounds in roasted mutton, using fiber derivatization-headspace solid phase microextraction-triple quadrupole gas chromatography-mass spectrometry technology, carbonyl compound internal standard curve is configured in a roasted mutton odorless matrix system, the roasted mutton odorless matrix preparation method is as follows: blank reagent water, triacetin and a matrix for removing a target substance from the roasted mutton are weighed respectively according to the moisture content, fat content and roasted mutton matrix content ratio of the target substance removed in the roasted mutton to prepare the roasted mutton odorless matrix, the target compound is integrated using a selected quantitative ion method, the mass spectrum characteristic ion is m / z181, most derivatives produce two or more isomers, in the absence of compound co-elution, the sum of the isomer peak areas is used for quantification, wherein for the interweaving of cis and trans isomer peaks of two compounds, for the convenience of integration, the second ion abundance is used as the quantitative ion (E)-2-octenal m / z250 and phenylacetaldehyde m / z117;

[0009] Draw a standard curve with the concentration ratio of the target substance to be measured and the internal standard substance as the horizontal axis and the peak area ratio of the target substance to be measured and the internal standard substance as the vertical axis;

[0010] The roasted mutton sample was measured under the same conditions to obtain the peak area ratio of each target substance to the internal standard in the roasted mutton sample, and the concentration of the corresponding carbonyl compound in the roasted mutton was calculated according to the standard curve, and the content of the carbonyl compound in the roasted mutton sample was calculated according to the formula;

[0011] The carbonyl compounds are 2-methylbutyraldehyde, 3-methylbutyraldehyde, valeraldehyde, hexanal, heptaldehyde, octanal, nonanal, decanal, dodecanal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, (E,E)-2,4-decadienal, benzaldehyde, phenylacetaldehyde, 2-heptanone, and 3-hydroxy-2-butanone.

[0012] Furthermore, the method comprises the following steps:

[0013] (1) Sample pretreatment:

[0014] The sample was prepared with liquid nitrogen and then ground into powder with a particle size of 50-100 μm using an analytical grinder. After weighing, blank reagent water was added as the test material, and an internal standard was added. The derivatization reagent was first loaded on the fiber, and then the sample was extracted and derivatized at the same time, and finally analyzed at the GC-MS / MS injection port.

[0015] (2) GC-MS / MS analysis:

[0016] Set up chromatography-mass spectrometry conditions;

[0017] (3) Qualitative analysis:

[0018] Use NIST database, relative retention index and standards for qualitative analysis;

[0019] (4) Quantitative analysis:

[0020] Using the internal standard standard curve method, 18 carbonyl compounds were mixed and dissolved, and a series of standard solutions were prepared in the roasted lamb tasteless matrix. The concentration ratio of the target to be measured and the internal standard was used as the horizontal axis, and the peak area ratio of the target to be measured and the internal standard was used as the vertical axis to draw the standard curve.

[0021] The roasted lamb samples were measured under the same conditions, and the sample concentration was calculated by substituting the ratio of the peak area of ​​the target compound in the sample to the peak area of ​​the internal standard into the calibration curve.

[0022] In the technical solution of the present invention, the mass ratio of blank reagent water, triacetin and roasted mutton matrix from which the target compound is removed is 50-60:15-25:20-30.

[0023] In the technical solution of the present invention, the mass ratio of the sample, water, internal standard and derivatization reagent in step (1) is (0.2-2) g: (1-8) g: (0.02-0.4) ug; (3-9) mg;

[0024] In the technical solution of the present invention, in step (1), the internal standard is 2-methylpentanal with a mass concentration of 3 to 10 ug / mL; the derivatization reagent is O-(2,3,4,5,6-pentafluorobenzyl)hydroxy hydrochloride with a concentration of 1 to 5 g / L.

[0025] In the technical scheme of the present invention, the derivatization method in step (1) is a fiber-based derivatization solid phase headspace microextraction method, which is to first insert an extraction needle into a headspace bottle containing a derivatization agent solution, load it at 40 to 60° C. for 5 to 10 minutes, then insert the extraction needle loaded with the derivatization agent into the sample, adsorb it for 20 to 40 minutes, and analyze it at an injection port at 240 to 260° C. for 2 to 5 minutes.

[0026] In the technical scheme of the present invention, the GC-MS / MS chromatography mass spectrometry conditions in step (2) are as follows: a capillary column SH-I-5SiI MS (30m×0.25mm×0.25μm), a temperature program: an initial column temperature of 40°C, maintained for 1 min, increased to 250°C at 5°C / min, maintained for 5 min, without splitting, and a constant flow mode of 1mL / min; the mass spectrometer detector is in EI mode, the transmission line temperature is 250°C, the ion source temperature is 200°C, and the full scan mode mass range is 50-500m / z.

[0027] In the technical solution of the present invention, the qualitative method in step (3) is based on mass spectrum library ion fragments, normal alkane retention index and / or standard retention time for qualitative analysis.

[0028] In the technical solution of the present invention, the method for removing the target substance from the meat product in step (4) is direct extraction and removal with an organic solvent or using a Soxhlet extraction apparatus, adding an organic solvent to a round-bottom flask, continuously extracting for 16-18 hours, discarding the organic solvent, and then treating the odorless sample residue with liquid nitrogen, freeze-drying for 12 hours, and no volatile flavor substances can be detected using solid phase microextraction-gas chromatography-mass spectrometry technology.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention provides a convenient, efficient, one-time quantitative detection method for 18 carbonyl compounds in roasted lamb samples.

[0031] (2) The present invention provides a method for preparing an odorless matrix in meat products. The prepared odorless matrix can highly restore the matrix of meat product samples and the matrix effect produced by the matrix, and the quantification is accurate.

[0032] (3) The present invention adopts O-(2,3,4,5,6-pentafluorobenzyl)hydroxy hydrochloride derivatization reagent fiber derivatization solid phase headspace microextraction method, which provides high sensitivity, low detection limit and quantitative detection for carbonyl compounds in meat products, and is suitable for the determination of carbonyl compounds in complex matrices.

[0033] (4) The mass-to-charge ratio of low molecular weight carbonyl compounds is below 100, and there are hundreds of compounds in the roasted lamb matrix, which has a large background interference. The derivatized carbonyl compounds can improve the chromatographic separation, the detectability of mass spectrometry fragments, and reduce background interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the method for simultaneously and quantitatively detecting 18 carbonyl compounds in roasted mutton in the embodiment;

[0035] Figure 2 The total ion chromatogram and m / z181 ion chromatogram of the standard working solutions of 18 carbonyl compounds in the embodiment;

[0036] Figure 3 The total ion chromatogram and m / z181 ion chromatogram of the roasted mutton sample of 18 carbonyl compounds in the embodiment;

[0037] Figure 4 PCA graphs of the roasted mutton sample spiked with the meat product tasteless matrix model in the meat product tasteless matrix embodiment and the comparative example, and the Euclidean distance between the spiked recombinant model and the roasted mutton sample.

[0038] Figure 5 It is a comparison chart of 18 carbonyl compounds detected in the examples and comparative examples. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto:

[0040] The 18 carbonyl compounds involved in the embodiments of the present invention are 2-methylbutanal, 3-methylbutanal, valeraldehyde, hexanal, heptanal, octanal, nonanal, decanal, dodecanal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, (E,E)-2,4-decadienal, benzaldehyde, phenylacetaldehyde, 2-heptanone, 3-hydroxy-2-butanone, and internal standard 2-methylvaleraldehyde and derivatization reagent O-(2,3,4,5,6-pentafluorobenzyl)hydroxy hydrochloride were purchased from Aladdin Reagent (Shanghai) Co., Ltd., and triacetin was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; blank reagent water: double distilled water or water prepared by pure water equipment, which must be blank tested before use to ensure that the concentration of the target compound is lower than the detection limit.

[0041] The instruments involved are triple quadrupole gas chromatograph-mass spectrometer (Shimadzu Corporation); capillary column SH-I-5SiI MS (30m×0.25mm×0.25μm) (Shimadzu Corporation); constant temperature water bath (Shanghai Lichen Bangsi Instrument Technology Co., Ltd.); electronic balance (Mettler-Toledo Instrument Shanghai Co., Ltd.), solid phase extraction needle, 65μm PDMS / DVB (SupElco Corporation, USA).

[0042] Example 1

[0043] 1. Sample Pretreatment

[0044] 1.1 Sample preparation

[0045] First, the roasted lamb was immediately frozen with liquid nitrogen, then chopped into powder using an analytical grinder within 30 seconds, and then the powder was transferred to an odorless, light-proof aluminum foil bag, stored at -80°C, and used within 14 days;

[0046] 1.2 Weighing

[0047] Weigh 1.00 g of sample, add 5.0 mL of blank reagent water, and add 20.0 μL of 2-methylpentanal internal standard with a concentration of 5 ug / mL;

[0048] 1.3 Loading of derivatization reagents onto fibers

[0049] 2.0 mL of 3 g / L derivatization reagent O-(2,3,4,5,6-pentafluorobenzyl)hydroxy hydrochloride was added into a brown headspace bottle, placed in a constant temperature magnetic stirring water bath at 50 °C, and adsorbed for 5 min using a 65 μm PDMS-DVB extraction needle;

[0050] 1.4 Simultaneous extraction and derivatization of roasted lamb samples:

[0051] The extraction needle loaded with the derivatization reagent was inserted into the sample preheated for 10 minutes and adsorbed at 50°C for 30 minutes.

[0052] 2. GC-MS / MS analysis

[0053] Chromatography mass spectrometry conditions:

[0054] Referring to the method of Maurizio Piergiovanni et al., GC-MS / MS analysis was performed, and a gas chromatography fused silica capillary column of SH-I-5SiI MS (30m×0.25mm×0.25μm) was used for chromatographic separation; non-split injection, constant flow mode 1mL / min, injection port temperature 250℃, desorption 5min; column oven temperature program: 40℃ for 1min, increased to 250℃ at 5℃ / min, and maintained for 5min; the mass spectrometer detector operated in EI mode, with a transfer line temperature of 250℃, an ion source temperature of 200℃, and a full scan mode mass range of 50-500m / z.

[0055] 3. Qualitative analysis

[0056] The identification of carbonyl compounds is shown in Table 1. The chromatograms of the standard working solution and roasted lamb sample and the 181 characteristic ion chromatograms are shown in Figure 2 and 3 The derivatization of carbonyl compounds with O-(2,3,4,5,6-pentafluorobenzyl)hydroxy hydrochloride produces two or more isomers. The mass spectral characteristic ion of the derivative is the pentafluorobenzene ion of m / z 181. Some of the peaks of the two compounds appear intertwined, and the second ion abundance is used as the quantitative ion (e.g., (E)-2-octenal and phenylacetaldehyde). Qualitative analysis is performed by comparing (a) the target fragment ions with the mass spectral library. The comparison with the mass spectral library is based on the comparison with the National Institute of Standards and Technology (NIST 20) mass spectral database, considering a similarity of >70%; (b) using a mixture of normal alkanes (C6-C30) to analyze the retention index of each reference compound and compare it with the retention index described in the literature; (c) identification is performed by the retention time of a single-label standard measured under the same conditions as the sample.

[0057] Table 1 Identification table of 18 carbonyl compounds

[0058]

[0059]

[0060] Note: MS mass spectral library; LRI relative retention index; S standard

[0061] 4. Quantitative Analysis

[0062] 4.1 Prepare a roasted lamb tasteless matrix;

[0063] 4.1.1 Determination of moisture content

[0064] Refer to GB / T 5009.3-2010 "Determination of water content in food";

[0065] 4.1.2 Determination of fat content

[0066] Refer to GB / T 14772-2008 "Determination of crude fat in foods";

[0067] 4.1.3 Other contents

[0068] Other contents mainly refer to protein and ash, which are determined by subtracting the percentage of moisture and fat content from the percentage of 100%. Note: Moisture is the largest component in meat products, and its content together with fat and protein content accounts for more than 95% of the quality of meat;

[0069] 4.1.4 Preparation of matrix for removal of target compounds from roasted lamb

[0070] The method for removing flavor substances in meat products is as follows: sample: ether: n-pentane = 1:2:1, shake on a shaker at room temperature for 12 hours, discard the organic solvent after filtering, repeat the above operation 3 times until the sample has no taste, and after liquid nitrogen treatment, freeze-dry the tasteless sample residue for 12 hours or use a Soxhlet extraction device, add a mixed solution of ether and n-pentane to a round-bottom flask, and extract continuously for 16-18 hours. No volatile flavor substances can be detected using SPME-GC-MS technology, and the roasted lamb tasteless matrix is ​​obtained;

[0071] 4.1.5 Prepare blank reagent water

[0072] Double distilled water or water prepared by pure water equipment must be blank tested before use to confirm that no interfering peaks appear within the retention time interval of the target compound or that the concentration of the target compound is lower than the detection limit of the method;

[0073] 4.1.6 Preparation of triacetin

[0074] 4.1.7 Preparation of odorless grilled lamb matrix

[0075] According to the ratio of 55% water content, 20% fat content and 25% other content in the roasted mutton sample, 1.00g of meat product odorless matrix was prepared, and 0.55g of blank reagent water, 0.20g of triacetin and 0.25g of roasted mutton matrix with the target compound removed were weighed;

[0076] 4.2 Configuration of series standard working solutions

[0077] 1.00g roasted mutton odorless matrix was weighed into a headspace bottle, 5.0mL blank reagent water was added as the sample, and 18 kinds of carbonyl compound mixed standard solutions were added respectively to prepare a series of concentration standard working solutions (concentration range is shown in Table 2), and then 20.0μL internal standard solution (2-methylpentanal) was added respectively; the derivatization reagent was loaded on the fiber: 2mL of 3g / L derivatization reagent was added to the brown headspace bottle, placed in a constant temperature magnetic stirring water bath at 50℃, and adsorbed for 5min using a 65μmPDMS-DVB extraction needle; then the standard was extracted and derivatized at the same time: the extraction needle loaded with the derivatization reagent was inserted into the standard solution preheated for 10min, and adsorbed at 50℃ for 30min; finally, the injection port was analyzed for 5min; GC-MS / MS determination was performed, and the peak area ratio of carbonyl compounds to internal standards was used as the ordinate, and the concentration ratio of carbonyl compounds to internal standards was used as the abscissa, and the quantitative relationship model of each compound was constructed respectively to calculate the content of 18 kinds of carbonyl compounds. The linear range, coefficient, detection limit (3 times signal-to-noise ratio) and quantification limit (lowest concentration of the standard curve) of the standard working curve of each compound are shown in Table 2. Linear regression was performed on the calibration data, and R 2 Should not be less than 0.95.

[0078] Table 2 Linear range, linear coefficient, detection limit and quantification limit of the method

[0079]

[0080]

[0081] 5. Result determination

[0082] The content of carbonyl compounds in the sample is calculated according to formula (1):

[0083]

[0084] Among them, C s It indicates the content of a certain organic compound in the sample, in ng / g; c is the concentration of carbonyl compounds, in μg / L;

[0085] m is the mass of the sample weighed, in g;

[0086] v is the sample volume in mL.

[0087] The roasted lamb samples were tested using the above method, repeated three times, and the results are shown in Table 3.

[0088] Table 3 Sample determination

[0089] Compound KB(ng / g) Test results (ng / g) 2-Methylbutyraldehyde Not detected 4.37±0.84 3-Methylbutyraldehyde Not detected 4.86±0.68 n-Valeraldehyde Not detected 706.58±57.67 3-Hydroxy-2-butanone Not detected Not detected (<400ug / L) n-Hexanal Not detected 4318.41±222.38 2-Heptanone Not detected 67.83±6.56 n-Heptanal Not detected 591.27±46.52 (E)-2-Heptenal Not detected 161.09±22.43 Octanal Not detected 370.55±54.22 Benzaldehyde Not detected 78.79±8.5 (E)-2-Octenal Not detected 137.48±15.85 Phenylacetaldehyde Not detected 66.1±9.95 Nonanal Not detected 1061.67±84.27 (E)-2-Nonenal Not detected 86.15±25.02 Decanal Not detected 7.80±0.83 (E)-2-Decenal Not detected 40.25±4.93 (E,E)-2,4-Decadienal Not detected 49.55±6.66 Dodecanal Not detected 4.39±0.49

[0090] Comparative ratio of meat product tasteless matrix

[0091] (1) Roasted mutton sample: Weigh 1.00 g of the sample into a 20 mL brown headspace bottle, add 5.0 mL of blank reagent water as the test material, and detect and analyze the roasted mutton sample according to the example.

[0092] (2) Model 1: The method for preparing the odorless matrix of meat products mentioned in the embodiment is as follows: 1.00 g of the odorless matrix is ​​prepared according to the ratio of 55% water content, 20% fat content and 25% other content in the roasted mutton sample. The specific operation is to weigh 0.55 g of blank reagent water, 0.20 g of triacetin and 0.25 g of roasted mutton matrix with the target compound removed into a 20 mL brown headspace bottle, add the carbonyl compound standard with the sample content shown in Table 3, add 5.0 mL of blank reagent water as the test material, and simulate the roasted mutton sample. Other operations are carried out according to the embodiment.

[0093] (3) Model 2: The meat product matrix with the target compound removed was prepared as follows: Sample: ether: n-pentane = 1:2:1, shake on a shaker at room temperature for 12 h, filter and discard the organic solvent, repeat the above operation 3 times until the sample has no taste, and after liquid nitrogen treatment, freeze-dry the tasteless sample residue for 12 h. No volatile flavor substances were detected using SPME-GC-MS technology. Weigh 1.00 g into a 20 mL brown headspace bottle, add the carbonyl compound standard with the sample content shown in Table 3, and add 5.0 mL of blank reagent water as a test material to simulate the roasted lamb sample. Other operations were performed according to the example.

[0094] (4) Model 3: Weigh 1.00 g of triacetin into a 20 mL brown headspace bottle, add carbonyl compound standards with sample contents shown in Table 3, and add 5.0 mL of blank reagent water as a test material to simulate a roasted lamb sample. Other operations were performed according to the example.

[0095] Through the above meat product tasteless matrix model and roasted lamb sample peak area analysis, according to the PCA results ( Figure 4 ), the principal component analysis accounted for 91% of the total variance. This result showed that the roasted lamb samples were different from Model 1, Model 2, and Model 3, such as Figure 4 As shown, the Euclidean distance between model 1 and the roasted lamb sample is smaller than that between model 2 and model 3. The smaller the Euclidean distance, the more similar it is to the sample. This result shows that the meat product tasteless matrix system constructed by the present invention is more effective and also proves the accuracy of the quantitative results.

[0096] Method Comparative Example 1

[0097] HS-SPME method for the detection of 18 carbonyl compounds

[0098] The reference Che Shen method is as follows, and the volatile compounds are extracted by HS-SPME. 1.00g of roasted lamb odorless matrix system was constructed into a 20mL headspace vial, 50ng of 17 carbonyl compounds except 3-hydroxy-2-butanone were added, and the vial was sealed with a polytetrafluoroethylene septum. The vial was placed in the sample tray of the automatic headspace injection system and heated at 50°C for 15 minutes of equilibrium and 30 minutes of extraction. The extraction was performed using an 80μm DVB / CarbonWR / PDMS extraction fiber. The fiber was inserted into the GC inlet and desorbed in splitless mode (250°C / 5min).

[0099] GC conditions: Use SH-I-5SiI MS (30m×0.25mm×0.25μm) column, constant flow mode, flow rate 1mL / min, injection port temperature 200℃, temperature program: maintain temperature at 40℃ for 3min, increase temperature to 120℃ at 5℃ / min, increase temperature to 200℃ at 10℃ / min, and maintain at 200℃ for 13min.

[0100] MS conditions: interface temperature 200°C, ion source temperature 200°C; ionization mode EI; ionization voltage 70EV; scanning range: 45-500 m / z.

[0101] Method Comparative Example 2

[0102] SAFE-GC-MS analysis

[0103] 50.00 g of roasted mutton odorless matrix system was constructed and placed in a 250 ml conical flask. 50 ng of 17 carbonyl compounds except 3-hydroxy-2-butanone were added. The sample was placed on a magnetic stirrer and stirred for 2 hours. The dichloromethane layer was collected by filtration and the extraction was repeated 3 times. The SAFE device was used to extract volatiles, and the supernatant organic layer was placed in a vacuum (<10 -3 Pa) with SAFE distillation, the circulating water temperature is set to 35 ° C, the cold trap is filled with liquid nitrogen, the distilled and concentrated samples are collected, a spoonful of anhydrous Na2SO4 is added and sealed for 12 hours, and then concentrated to 4 ml with a VigrEux column at 50 ° C, and concentrated to 1 ml under nitrogen flow. The concentrated extract is sealed and stored in a 1.5 mL high-performance liquid chromatography bottle and used up within 3 days.

[0104] GC conditions: SH-I-5SiI MS (30m×0.25mm×0.25μm) column, constant flow mode, flow rate 1mL / min. Inlet temperature 200℃. Heating program: keep at 35℃ for 2min, increase to 120℃ at 5℃ / min, increase to 200℃ at 10℃ / min, keep for 5min, increase to 280℃ at 5℃ / min, keep for 10min.

[0105] MS conditions are the same as 2.3.

[0106] 50 ng of carbonyl compound was added to the Example and Comparative Examples 1 and 2 for analysis, and the peak areas of the obtained compounds are shown in Table 4. The carbonyl compound of the same concentration could not be detected in Comparative Examples 1 and 2. This result shows that the method constructed by the present invention has high sensitivity, and the detection limit and quantification limit are higher than those of conventional pretreatment methods.

[0107] Through the example and comparative examples 1 and 2, 18 carbonyl compounds in the roasted mutton samples were analyzed respectively, and the Venn diagram is shown as follows Figure 5 As shown, 18 species were detected using the quantitative method of the present invention, 12 species were detected using SPME, and 11 species were detected using SAFE. This result shows that the detection effect of the present invention is more obvious for the 18 carbonyl compounds of the present invention.

[0108] Table 4 Detection peak area of ​​carbonyl compounds with a content of 50ng

[0109]

[0110]

[0111] It can be seen from the above embodiments that the present invention uses the prepared meat product tasteless matrix to establish an internal standard curve, and then uses fiber derivatization solid phase microextraction for pretreatment combined with GC-MS / MS analysis to quantitatively detect and analyze 18 carbonyl compounds in the meat matrix. The method has high sensitivity, low detection limit and quantification limit, accurate quantification, and is easy to promote and use.

[0112] Although the above content elaborates on the specific implementation modes of the present invention, these descriptions do not constitute strict limitations on the present invention. Any professional familiar with the technical field can make appropriate adjustments and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined according to the provisions of the claims.

Claims

1. A method for quantitatively detecting carbonyl compounds in roasted mutton, characterized in that: The fiber derivatization-headspace solid phase microextraction-triple quadrupole gas chromatography-mass spectrometry technology was used, and the internal standard curve of carbonyl compounds was configured in the roasted mutton odorless matrix system. The method for preparing the roasted mutton odorless matrix was as follows: blank reagent water, triacetin and the matrix for removing the target substance in the roasted mutton were weighed according to the moisture content, fat content and the ratio of the roasted mutton matrix content after removing the target substance, respectively, to prepare the roasted mutton odorless matrix. The target compound was integrated using the selected quantitative ion method, and the mass spectrum characteristic ion was m / z181. Most derivatives produced two or more isomers. In the absence of co-elution of compounds, the sum of the isomer peak areas was used for quantification. For the interweaving of the cis and trans isomer peaks of the two compounds, the second ion abundance was used as the quantitative ion (E)-2-octenal m / z250 and phenylacetaldehyde m / z117 for the convenience of integration. Draw a standard curve with the concentration ratio of the target substance to be measured and the internal standard substance as the horizontal axis and the peak area ratio of the target substance to be measured and the internal standard substance as the vertical axis; The roasted mutton sample was measured under the same conditions to obtain the peak area ratio of each target substance to the internal standard in the roasted mutton sample, and the concentration of the corresponding carbonyl compound in the roasted mutton was calculated according to the standard curve, and the content of the carbonyl compound in the roasted mutton sample was calculated according to the formula; The carbonyl compounds are 2-methylbutyraldehyde, 3-methylbutyraldehyde, valeraldehyde, hexanal, heptaldehyde, octanal, nonanal, decanal, dodecanal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, (E,E)-2,4-decadienal, benzaldehyde, phenylacetaldehyde, 2-heptanone, and 3-hydroxy-2-butanone.

2. The method for quantitative detection of carbonyl compounds in roasted mutton according to claim 1, characterized in that: The method comprises the following steps: (1) Sample pretreatment: The sample was prepared with liquid nitrogen and then ground into powder with a particle size of 50-100 μm using an analytical grinder. After weighing, blank reagent water was added as the test material, and an internal standard was added. The derivatization reagent was first loaded on the fiber, and then the sample was extracted and derivatized at the same time, and finally analyzed at the GC-MS / MS injection port. (2) GC-MS / MS analysis: Set up chromatography-mass spectrometry conditions; (3) Qualitative analysis: Use NIST database, relative retention index and standards for qualitative analysis; (4) Quantitative analysis: Using the internal standard standard curve method, 18 carbonyl compounds were mixed and dissolved, and a series of standard solutions were prepared in the roasted lamb tasteless matrix. The concentration ratio of the target to be measured and the internal standard was used as the horizontal axis, and the peak area ratio of the target to be measured and the internal standard was used as the vertical axis to draw the standard curve. The roasted lamb samples were measured under the same conditions, and the sample concentration was calculated by substituting the ratio of the peak area of ​​the target compound in the sample to the peak area of ​​the internal standard into the calibration curve.

3. The method for quantitative detection of carbonyl compounds in roasted mutton according to claim 1, characterized in that: The mass ratio of blank reagent water, triacetin and roasted lamb matrix from which the target compound has been removed is 50-60:15-25:20-30.

4. The method for detecting carbonyl compounds in roasted mutton according to claim 2, characterized in that: The mass ratio of the sample, water, internal standard and derivatization reagent in step (1) is (0.2-2) g: (1-8) g: (0.02-0.4) ug; (3-9) mg.

5. The method for quantitative detection of carbonyl compounds in roasted mutton according to claim 4, characterized in that: In step (1), the internal standard is 2-methylpentanal with a mass concentration of 3 to 10 ug / mL; the derivatization reagent is O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride with a concentration of 1 to 5 g / L.

6. The method for quantitatively detecting carbonyl compounds in roasted mutton according to claim 2, characterized in that: The derivatization method in step (1) is a fiber-based derivatization solid phase headspace microextraction method, which includes first inserting an extraction needle into a headspace bottle containing a derivatization agent solution, loading the solution at 40 to 60° C. for 5 to 10 minutes, then inserting the derivatization agent-loaded extraction needle into the sample, adsorbing the solution for 20 to 40 minutes, and performing desorption at an injection port at 240 to 260° C. for 2 to 5 minutes.

7. The method for quantitatively detecting carbonyl compounds in roasted mutton according to claim 2, characterized in that: The GC-MS / MS chromatography mass spectrometry conditions in step (2) are as follows: capillary column SH-I-5SiIMS (30m×0.25mm×0.25μm), heating program: initial column temperature 40°C, hold for 1 min, increase to 250°C at 5°C / min, hold for 5 min, no split, constant flow mode 1mL / min; mass spectrometer detector is EI mode, transmission line temperature 250°C, ion source temperature 200°C, full scan mode mass range 50-500m / z.

8. The method for quantitatively detecting carbonyl compounds in roasted mutton according to claim 2, characterized in that: The qualitative method in step (3) is based on mass spectral library ion fragments, normal alkane retention index and / or standard retention time.

9. The method for quantitatively detecting carbonyl compounds in roasted mutton according to claim 2, characterized in that: In step (4), the method for removing the target substance from the meat product is direct extraction with an organic solvent or using a Soxhlet extraction apparatus, adding an organic solvent to a round-bottom flask, continuously extracting for 16-18 hours, discarding the organic solvent, and then treating the odorless sample residue with liquid nitrogen and freeze-drying it for 12 hours. No volatile flavor substances can be detected using solid phase microextraction-gas chromatography-mass spectrometry technology.

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