Method for detecting characteristic volatile aroma in a baobao pickle

Abstract

The application discloses a detection method of characteristic volatile aroma in eight-treasure pickles, which comprises the following steps: placing the stirred eight-treasure pickle sample in a headspace bottle for solid phase microextraction, then performing gas chromatography-mass spectrometry analysis, and collecting and analyzing data; installing a shunt at the end of the chromatographic column, shunting to a mass spectrometer and a smell instrument, having a professional smell person sit at the outlet of the smell instrument, smelling and recording the smell and aroma information obtained in the gas flow process, and obtaining target aroma components; obtaining the content of the target aroma components through gas chromatography-mass spectrometry analysis, calculating the ratio of the content and a threshold value, obtaining the aroma activity value of each aroma component, and judging the main aroma components in the eight-treasure pickles. The application adopts SPME-GC-MS and GC-O to identify the main aroma components of the eight-treasure pickles, and is more scientific and efficient to ensure the quality uniformity of the products under the same pickling process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food detection, in particular, the present application relates to a kind of detection method of characteristic volatile aroma in eight treasure pickles.More specifically, the present application is analyzed the method of characteristic volatile aroma in eight treasure pickles by headspace solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) combined with smell aroma instrument (GC-O). BACKGROUND

[0002] Eight treasure pickles are a kind of pickles made by pickling a variety of food materials, usually with cucumber, cowpea, lotus root, mustard and other vegetables such as radish, chili, sweet, soybean, etc. Eight treasure pickles have various tastes, and the pickling methods vary from region to region, but the common point is that they are crisp, tender, fragrant, rich in sauce, and have a rich taste, which is deeply loved by people. Some of the flavoring substances in eight treasure pickles are brought by the food materials themselves, some are carried by the spices added during pickling, and the final taste is formed through microbial fermentation in the later stage. Therefore, the composition of flavoring substances that form aroma in pickled vegetables is very complex, and aroma is an important indicator for evaluating the quality of pickled vegetables. At present, the quality control of pickled vegetables is mainly sensory evaluation, and few instruments are used to analyze the flavor, so the evaluation results are more subjective and lack scientific basis. SUMMARY

[0003] On the basis of the prior art, the present application uses headspace solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) combined with smell aroma instrument (GC-O) to analyze the characteristic aroma in pickled vegetables, and explores the main aroma components in eight treasure pickles, providing a scientific basis for product production and quality control.

[0004] The technical scheme adopted by the present application is as follows:

[0005] The present application provides a kind of detection method of characteristic volatile aroma in eight treasure pickles, comprising the following steps:

[0006] (3) Pretreatment of the sample to be tested: the eight treasure pickles are fully stirred and crushed in a blender to obtain eight treasure pickles samples for standby;

[0007] (4) Solid phase microextraction: place the eight treasure pickles sample in a headspace bottle, heat at 60℃ for 20min, insert the activated extraction head into the headspace bottle, heat to 60℃, and extract for 30min, then take out and quickly insert the extraction head into the sample inlet of gas chromatograph, desorb at 250℃ for 10min, and perform gas chromatography-mass spectrometry analysis, and collect and analyze data;

[0008] (3) install a flow splitter at the end of the chromatographic column, split to a mass spectrometer and an olfactometer, a professional olfactory person sits at the outlet of the olfactometer, smells and records the smell and aroma information obtained during the gas flow, and obtains the target aroma components;

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

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

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

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

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

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

[0015] In some embodiments, the ratio of the split to the mass spectrometer and the olfactometer is 2:1.

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

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

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

[0019] The application identifies the main aroma components of eight treasure pickles by adopting SPME-GC-MS combined with GC-O, and the data analysis is more scientific and efficient to ensure the quality uniformity of products under the same pickling process. BRIEF DESCRIPTION OF DRAWINGS

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

[0021] Figure 1 is the total ion chromatogram of eight treasure pickles. DETAILED DESCRIPTION

[0022] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0023] The instruments involved in the embodiments of the present application are as follows: gas chromatograph-mass spectrometer: Agilent 8890-5977; smell 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 detection method of characteristic volatile aroma in eight treasure pickles, comprising the following steps:

[0026] (1) Take 50g of eight treasure pickles, put them into a machine for crushing, mix them evenly, and then reserve; accurately take 1.0g of the crushed and mixed evenly eight treasure pickle sample to (0.01g), place it in a 15mL headspace bottle, heat it on a multifunctional constant temperature heater at 60℃ for 20min, insert the activated extraction head (50 / 30μm DVB / CAR / PDMS solid phase microextraction fiber head) into the headspace bottle, with the extraction head located about 1cm above the sample in the headspace bottle, heat to 60℃, extract for 30min, then take it out and quickly insert the extraction head into the gas chromatograph inlet, desorb at 250℃ for 10min, start the gas chromatograph-mass spectrometer (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 x 0.25 mm x 0.25 μm, Agilent Technologies, USA), injection port temperature 250 °C, carrier gas high-purity helium (99.999 %), carrier gas flow rate 1.0 mL / min, programmed temperature: initial temperature 40 °C, holding for 2.0 min, increasing at 3 °C / min to 180 °C, then increasing at 10 °C / min to 250 °C 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; tuning in standard mode; full scan (SCAN) mode was selected, mass scan range: 40-450 amu.

[0030] A split port was installed at the end of the chromatographic column, and the split ratio was 2:1 to split the sample to the mass spectrometer and the odor instrument. A professional odor detection person sat at the outlet of the odor instrument, smelled and recorded the aroma and aroma information obtained during the gas flow, and obtained the target aroma components;

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

[0032] GC-MS analysis results

[0033] The volatile flavor substances in the eight treasure pickles were extracted by SPME and subjected to GC-MS analysis, and the results showed that the volatile flavor substances in the eight treasure pickles were complex, and the sample chromatogram was as shown in Figure 1 A total of 35 volatile aroma components 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 eight treasure pickles

[0035]

[0036] As shown in Table 1, among the characteristic flavor substances of the eight treasure pickles, the highest proportion of alkenes was gingerene, the highest proportion of alcohols was eucalyptol, the highest proportion of aldehydes was citral, the highest proportion of ethers was diallyl trisulfide, and the highest proportion of ketones was ar-tumerone. Overall analysis showed that alkenes had the highest proportion and played a major role in the flavor substances of the eight treasure pickles.

[0037] GC-O analysis results

[0038] It is found by GC-O sniffing analysis that not every volatile flavor substance has aroma, so in order to further determine the characteristic aroma components in the eight-treasure pickles, it is necessary to judge each volatile aroma component according to the aroma activity value thereof. The aroma threshold of the volatile aroma components in the eight-treasure pickles is obtained by consulting the "Compilation of Compound Aroma Thresholds", and Table 2 is the volatile aroma components (target aroma components) in the eight-treasure pickles and their aroma activity values:

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

[0040]

[0041] The aroma activity value table 2 in the eight-treasure pickles shows that eucalyptol, linalool, ethyl maltol, neral, citral and camphene are the six aroma substances with higher aroma activity values in the eight-treasure pickles, which provide the main role for the flavor of the eight-treasure pickles. The aroma components with aroma activity value > 1 in the remaining eight-treasure pickles are α-pinene, citronellol, 2-citronellol, diallyl trisulfide and myrcene, which shows that the aroma concentration of these five aroma substances is higher than the threshold value, so they also contribute to the overall flavor of the eight-treasure pickles. These 11 substances can be used as the fingerprint of the eight-treasure pickles.

[0042] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for detecting characteristic volatile aroma in a Baobab sauce, characterized in that, It comprises the following steps: (1) Pretreatment of the sample to be tested: the eight treasure pickles are fully stirred in a blender to obtain the eight treasure pickle sample, which is ready for use; (2) Solid phase microextraction: the eight treasure pickle sample is placed in a headspace bottle, heated at 60℃ for 20min, the activated extraction head is inserted into the headspace bottle, heated to 60℃, and extracted for 30min, then taken out and quickly inserted into the gas chromatograph inlet, desorbed at 250℃ for 10min, and analyzed by gas chromatography-mass spectrometry, and data collection and analysis are performed; (3) Install a flow divider at the end of the chromatographic column, and divide the flow to the mass spectrometer and the odor instrument. The professional odor detection personnel sit at the outlet of the odor instrument, smell and record the aroma and aroma information obtained during the gas flow, and obtain the target aroma components; (4) Obtain the content of the target aroma components by gas chromatography-mass spectrometry analysis, calculate the ratio of the content to the threshold value, obtain the aroma activity value of each aroma component, and determine the main aroma components in the eight treasure pickles; The extraction head of the solid phase microextraction is: 50 / 30μm DVB / CAR / PDMS solid phase microextraction fiber head; The gas chromatography conditions are: HP-5MS capillary column, 30m×0.25mm×0.25μm, inlet temperature 250℃, carrier gas is high-purity helium, carrier gas flow rate is 1.0 mL / min, programmed temperature: initial temperature 40℃, hold for 2.0min, increase by 3℃ / min to 180℃, then increase by 10℃ / min to 250℃ and hold for 10.0min; The mass spectrometry conditions are: EI ion source; electron energy 70 eV; quadrupole temperature 150℃, interface temperature 250℃; electron multiplier voltage 1281V; ion source temperature 230℃; standard mode is used for tuning; full scan mode is selected, mass scan range: 40-450amu; In step (4), the aroma components with aroma activity value ≥1 are used as the fingerprint of the eight treasure pickles; The fingerprint includes eucalyptol, linalool, ethyl maltol, neral, citral, camphene, alpha-pinene, citronellol, 2-citral, diallyl trisulfide and myrcene.

2. The method according to claim 1, wherein the characteristic volatile aroma of the eight-treasure pickle is detected. The activated extraction head refers to the extraction head activated at 250℃ for 30min.

3. The method according to claim 2, wherein the characteristic volatile aroma of the eight-treasure pickle is detected. The extraction head is inserted into the headspace bottle, and the extraction head is located 1cm above the sample in the headspace bottle.

4. The method according to claim 1, wherein the characteristic volatile aroma of the eight-treasure pickle is detected. The flow division ratio of the flow divided to the mass spectrometer and the odor instrument is 2:1.

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