Method for detecting characteristic volatile aroma in eight-treasure pickles

Abstract

The invention discloses a method for detecting characteristic volatile aroma in eight-treasure pickles, which comprises the following steps: putting a mashed eight-treasure pickle sample into a headspace bottle for solid-phase microextraction, then carrying out gas chromatography-mass spectrometry analysis, and carrying out data acquisition and analysis; a flow dividing opening is formed in the tail end of the chromatographic column, flow is divided into a mass spectrometer and an aroma smelling instrument, a professional smelling person sits at an outlet of the aroma smelling instrument, smells and records aroma obtained in the gas flowing process and aroma information of the aroma, and target aroma components are obtained; the content of target aroma components is obtained through gas chromatography-mass spectrometry analysis, the aroma activity value of each aroma component is obtained by calculating the ratio of the content to a threshold value, and the main aroma components in the eight-treasure pickles are judged. According to the method disclosed by the invention, the main aroma components of the eight-treasure pickles are identified by combining SPME-GC-MS and GC-O, so that the quality uniformity of products under the same pickling process is more scientifically and efficiently ensured.

Description

Technical Field

[0001] The present invention relates to the field of food detection, and in particular, to a method for detecting characteristic volatile aroma in eight-treasure pickles. More specifically, the present invention is a method for analyzing characteristic volatile aroma in eight-treasure pickles by combining headspace solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) with an aroma analyzer (GC-O). Background Art

[0002] Babao pickles are pickled vegetables made from a variety of ingredients, usually with cucumbers, cowpeas, lotus roots, mustard greens, etc. as the main ingredients, and other vegetables such as dried radish, peppers, manna, soybeans, etc. are added. Babao pickles have various flavors, and the pickling techniques vary depending on the region, but the common point is that they are crisp, tender, fragrant, rich in sauce flavor, and rich in taste, which are deeply loved by people. Some of the flavor substances in Babao pickles are brought by the ingredients themselves, and some are carried by the spices added during pickling. Later, they are fermented by microorganisms to finally form the taste that people are exposed to in daily life. Therefore, the composition of the flavor substances that form the aroma in pickled vegetables is very complex. Aroma is an important indicator for evaluating the quality of pickled vegetables. At present, the quality control of pickled vegetables is mostly sensory evaluation, and instrumental analysis methods are rarely used to determine its flavor. The evaluation results are relatively subjective and lack scientific basis. Summary of the invention

[0003] Based on the existing technology, the present invention adopts headspace solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and aroma smelling instrument (GC-O) to analyze the characteristic aroma in pickled vegetables, explore the main aroma components in eight-treasure pickles, and provide a scientific basis for product production and quality control.

[0004] The technical solution adopted by the present invention is as follows:

[0005] The present invention provides a method for detecting characteristic volatile aroma in eight-treasure pickles, comprising the following steps:

[0006] (3) Pretreatment of the sample to be tested: fully blend the eight-treasure pickles in a blender to obtain eight-treasure pickles samples for later use;

[0007] (4) Solid phase microextraction: The eight-treasure pickled vegetable sample was placed in a headspace bottle, heated to 60°C for 20 min, and the activated extraction head was inserted into the headspace bottle and heated to 60°C. After headspace extraction for 30 min, the extraction head was taken out and quickly inserted into the injection port of the gas chromatograph, desorbed at 250°C for 10 min, and analyzed by gas chromatography-mass spectrometry, and data acquisition and analysis were performed;

[0008] (3) Install a split port at the end of the chromatographic column to split the gas into a mass spectrometer and an aroma meter. A professional olfactory technician sits at the outlet of the aroma meter to smell and record the aroma and aroma information obtained during the gas flow process to obtain the target aroma components;

[0009] (4) The content of the target aroma component is obtained by gas chromatography-mass spectrometry analysis. The aroma activity value of each aroma component is obtained by calculating the ratio of the content to the threshold value, and the main aroma components in eight-treasure pickles are determined.

[0010] In some embodiments, the solid phase microextraction extraction head is: 50 / 30 μm DVB / CAR / PDMS solid phase microextraction fiber head, Supelco, USA.

[0011] In some embodiments, the activated extraction head refers to an extraction head activated at 250° C. for 30 minutes.

[0012] In some embodiments, the extraction head is inserted into the headspace vial, and the extraction head is located 1 cm above the sample in the headspace vial.

[0013] In some embodiments, the gas chromatography conditions are: HP-5MS capillary column, 30m×0.25mm×0.25μm, injection port temperature 250°C, carrier gas is high purity helium, carrier gas flow rate is 1.0mL / min, program temperature rise: starting temperature 40°C, hold for 2.0min, increase to 180°C at 3°C / min, and then increase to 250°C at 10°C / min and hold for 10.0min.

[0014] In some embodiments, the mass spectrometry conditions are: EI ion source; electron energy 70eV; quadrupole temperature 150°C, interface temperature 250°C; electron multiplier voltage 1281V; ion source temperature 230°C; standard tuning; full scan (SCAN) mode, mass scan range: 40-450amu.

[0015] In some embodiments, the ratio of splitting to the mass spectrometer and the aromameter is 2:1, respectively.

[0016] In some embodiments, in step (4), aroma components with aroma activity values ​​≥ 1 are used as the fingerprint of eight-treasure pickles.

[0017] In some embodiments, the fingerprint includes eucalyptol, linalool, ethyl maltol, neral, citral, camphene, α-pinene, citronellol, 2-camphene, diallyl trisulfide and myrcene.

[0018] The present invention has the following advantages and beneficial effects:

[0019] The present invention adopts SPME-GC-MS combined with GC-O to identify the main aroma components of eight-treasure pickles, and combines data analysis to more scientifically and efficiently ensure the quality uniformity of products under the same pickling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 This is the total ion chromatogram of Babao pickles. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0023] The instruments involved in the embodiments of the present invention are as follows: gas chromatograph-mass spectrometer: Agilent 8890-5977; aroma instrument: Brechbuhler Switzerland; capillary column: Agilent HP-5MS; solid phase extraction column: Supelco USA; multifunctional constant temperature heater: AUTO SCIENCE China.

[0024] Example 1

[0025] A method for detecting characteristic volatile aroma in eight-treasure pickles comprises the following steps:

[0026] (1) Weigh 50 g of eight-treasure pickles, put them into a machine for crushing, mix them evenly, and set them aside; accurately weigh 1.0 g of the crushed and evenly mixed eight-treasure pickles sample to the nearest (0.01 g), put it into a 15 mL headspace bottle, heat it on a multifunctional constant temperature heater at 60°C for 20 min, insert an activated (250°C, 30 min) extraction head (50 / 30 μm DVB / CAR / PDMS solid phase microextraction fiber head) into the headspace bottle, and place the extraction head about 1 cm above the sample in the headspace bottle. Heat it to 60°C, take it out after 30 min of headspace extraction, and quickly insert the extraction head into the inlet of a gas chromatograph, desorb it at 250°C for 10 min, start the gas chromatography-mass spectrometry (GC-MS) instrument, and perform data acquisition and analysis.

[0027] (2) Analysis

[0028] The gas chromatography conditions were set as follows: HP-5MS capillary column (30 m × 0.25 mm × 0.25 μm, Agilent Technologies, Inc., USA), inlet temperature of 250 °C, carrier gas of high purity helium (99.999%), carrier gas flow rate of 1.0 mL / min, and programmed temperature: starting temperature of 40 °C, maintained for 2.0 min, increased to 180 °C at 3 °C / min, and then increased to 250 °C at 10 °C / min for 10.0 min.

[0029] The mass spectrometry conditions were set as follows: EI ion source; electron energy 70 eV; quadrupole temperature 150°C, interface temperature 250°C; electron multiplier voltage 1281 V; ion source temperature 230°C; standard tuning; full scan (SCAN) mode, mass scan range: 40-450 amu.

[0030] A split port is installed at the end of the chromatographic column, with a split ratio of 2:1 to split the sample to the mass spectrometer and the aroma meter. A professional olfactory technician sits at the outlet of the aroma meter to smell and record the aroma and aroma information obtained during the gas flow process to obtain the target aroma components.

[0031] The content of target aroma components was obtained by gas chromatography-mass spectrometry analysis. The aroma activity value of each aroma component was obtained by calculating the ratio of the content to the threshold value, and the main aroma components in eight-treasure pickles were determined.

[0032] GC-MS analysis results

[0033] The volatile flavor substances in Babao pickles were extracted by SPME and analyzed by GC-MS. The results showed that the volatile flavor substances in Babao pickles were complex. The sample chromatogram is as follows: Figure 1 A total of 35 volatile aromas were obtained, including 3 aldehydes, 7 alcohols, 15 alkenes, 3 ketones, 2 ethers, 2 esters, 2 phenols, and 1 acid. The specific volatile aroma components are shown in Table 1.

[0034] Table 1 Volatile aroma components in Babao pickles

[0035]

[0036] As shown in Table 1, among the characteristic flavor substances of Babao pickles, gingerol has the highest proportion in olefins, eucalyptol has the highest proportion in alcohols, citral has the highest proportion in aldehydes, diallyl trisulfide has the highest proportion in ethers, and aromatic turmeric flavonoids has the highest proportion in ketones. Overall analysis shows that olefins have the highest proportion and play a major role in the flavor substances of Babao pickles.

[0037] GC-O analysis results

[0038] After GC-O olfactory analysis, it was found that not every volatile flavor substance has aroma. Therefore, in order to further determine the characteristic aroma components in Babao pickles, it is necessary to judge them according to the aroma vitality value of each volatile aroma component. By consulting the "Compilation of Compound Aroma Threshold Values", the aroma thresholds of volatile aroma components in Babao pickles were obtained. Table 2 shows the volatile aroma components (target aroma components) and their aroma vitality values ​​in Babao pickles:

[0039] Table 2GC-O analysis of volatile aroma components and their activity values ​​in Babao pickles

[0040]

[0041] Table 2 shows that the aroma activity values ​​in Babao pickles show that eucalyptol, linalool, ethyl maltol, neral, citral, and camphene are the six aroma substances with higher aroma activity values ​​in Babao pickles, which play a major role in the flavor of Babao pickles. The remaining aroma components with aroma activity values ​​greater than 1 in Babao pickles include α-pinene, citronellol, 2-camphenol, diallyl trisulfide, and myrcene, indicating that the aroma concentrations of these five aroma substances are higher than their threshold values, and thus contribute to the overall flavor of Babao pickles. These 11 substances can be used as the fingerprint of Babao pickles.

[0042] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for detecting characteristic volatile aroma in eight-treasure pickles, characterized in that: The steps include: (1) Pretreatment of the sample to be tested: fully blend the eight-treasure pickles in a blender to obtain the eight-treasure pickles sample for later use; (2) Solid phase microextraction: The eight-treasure pickled vegetable sample was placed in a headspace bottle, heated to 60°C for 20 min, and the activated extraction head was inserted into the headspace bottle and heated to 60°C. After headspace extraction for 30 min, the extraction head was taken out and quickly inserted into the injection port of the gas chromatograph, desorbed at 250°C for 10 min, and analyzed by gas chromatography-mass spectrometry, and data acquisition and analysis were performed; (3) Install a split port at the end of the chromatographic column to split the gas into a mass spectrometer and an aroma meter. A professional olfactory technician sits at the outlet of the aroma meter to smell and record the aroma and aroma information obtained during the gas flow process to obtain the target aroma components; (4) The content of the target aroma component is obtained by gas chromatography-mass spectrometry analysis. The aroma activity value of each aroma component is obtained by calculating the ratio of the content to the threshold value, and the main aroma components in eight-treasure pickles are determined.

2. The method for detecting characteristic volatile aroma in eight-treasure pickles according to claim 1, characterized in that: The solid phase microextraction extraction head is: 50 / 30μm DVB / CAR / PDMS solid phase microextraction fiber head.

3. The method for detecting characteristic volatile aroma in eight-treasure pickles according to claim 2, characterized in that: The activated extraction head refers to the extraction head activated at 250° C. for 30 minutes.

4. The method for detecting characteristic volatile aroma in eight-treasure pickles according to claim 2, characterized in that: The extraction head is inserted into the headspace bottle, and the extraction head is located 1 cm above the sample in the headspace bottle.

5. A method for detecting characteristic volatile aroma in eight-treasure pickles according to any one of claims 1 to 4, characterized in that: The gas chromatography conditions were as follows: HP-5MS capillary column, 30 m × 0.25 mm × 0.25 μm, injection port temperature 250 °C, carrier gas was high-purity helium, carrier gas flow rate was 1.0 mL / min, programmed temperature rise: starting temperature 40 °C, maintained for 2.0 min, increased to 180 °C at 3 °C / min, and then increased to 250 °C at 10 °C / min and maintained for 10.0 min.

6. A method for detecting characteristic volatile aroma in eight-treasure pickles according to any one of claims 1 to 4, characterized in that: The mass spectrometry conditions were as follows: EI ion source; electron energy 70 eV; quadrupole temperature 150°C, interface temperature 250°C; electron multiplier voltage 1281 V; ion source temperature 230°C; standard tuning; full scan (SCAN) mode, mass scan range: 40-450 amu.

7. A method for detecting characteristic volatile aroma in eight-treasure pickles according to any one of claims 1 to 4, characterized in that: The split ratio to the mass spectrometer and the aroma instrument is 2:1 respectively.

8. The method for detecting characteristic volatile aroma in eight-treasure pickles according to claim 7, characterized in that: In step (4), the aroma components with aroma activity values ​​≥ 1 are used as the fingerprint of eight-treasure pickles.

9. The method for detecting characteristic volatile aroma in eight-treasure pickles according to claim 8, characterized in that: The fingerprint spectrum includes eucalyptol, linalool, ethyl maltol, neral, citral, camphene, α-pinene, citronellol, 2-camphene, diallyl trisulfide and myrcene.

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