Method for constructing fingerprints of nutrient substances and characteristics in yellow cattle meat

Abstract

The invention discloses a method for constructing nutrient substances in yellow cattle meat and a characteristic fingerprint spectrum, which can be used for excavating functional nutrient substances such as sarcosine, carnitine and the like in the yellow cattle meat, screening out characteristic aroma compounds which greatly contribute to the overall flavor of a sample and establishing the characteristic flavor fingerprint spectrum of the yellow cattle meat. The construction method of the fingerprints of the nutrient substances and the characteristics in the yellow cattle meat comprises the following steps: S1, collecting a sample; S2, detecting the variety and the content of volatile flavor substances in the sample by adopting a GC-MS detection method; establishing a fingerprint spectrum of nutrient substances and characteristics in the yellow cattle meat; and S3, detecting and analyzing a detection result. By adopting the method for constructing the fingerprints of the nutrient substances and the characteristics in the yellow cattle meat, the quality characteristic and nutritional characteristic data of various yellow cattle meat can be accurately obtained, and a quality characteristic and nutritional characteristic database of the yellow cattle meat is established; accurate selection of cattle breeding varieties is realized; breeding and improvement of cattle varieties are facilitated; the economic benefits of farmers can be conveniently improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gamma spectrum analysis, and particularly relates to a method for constructing a characteristic fingerprint spectrum of nutrients in yellow cattle meat. BACKGROUND

[0002] Yellow cattle is a native common cattle breed in China. Yellow cattle has strong adaptability, tolerates coarse feed, and has good grazing performance. In hot seasons, yellow cattle does not fear sunlight and does not fear the scorching heat. Yellow cattle normally eats, grazes and ruminates. In cold seasons, yellow cattle does not fear the severe cold and does not fear the strong wind, and continues to eat the pastures and roots. In the long winter and spring seasons, yellow cattle has less weight loss, less spring hunger and less death. In the sparse desert and grassland, yellow cattle can regain weight and become strong only by grazing. Yellow cattle not only has strong disease resistance, but also has special resistance to many diseases. Therefore, yellow cattle is easy to raise.

[0003] In the process of raising yellow cattle, many aspects are involved, such as breeding technology, breed selection, feeding management, disease prevention and treatment and the like. Among them, the feeding technology is the basis for raising yellow cattle, and only good feeding technology can ensure correct feeding and healthy feeding of yellow cattle. In order to ensure the meat quality of yellow cattle, the breed selection is particularly important. Selecting high-quality yellow cattle breeds is the key to success. The traditional breed selection is generally to select strong male cattle and well-developed female cattle.

[0004] The traditional breed selection cannot accurately determine the nutrient content and flavor characteristics of the corresponding breed of yellow cattle meat, and therefore the traditional breed selection is an experience selection, which cannot guarantee the accurate selection of the breed of yellow cattle. SUMMARY

[0005] The present application solves the technical problem of providing a method for constructing a characteristic fingerprint spectrum of nutrients in yellow cattle meat, which can mine functional nutrients such as sarcosine and carnitine in yellow cattle meat, screen characteristic aroma compounds that contribute more to the overall flavor of the sample, establish a characteristic flavor fingerprint spectrum of Huangping yellow cattle meat, and improve the detection accuracy.

[0006] The technical solution adopted by the present application to solve the technical problem is: the method for constructing a characteristic fingerprint spectrum of nutrients in yellow cattle meat, characterized in that it comprises the following steps:

[0007] S1, sample collection;

[0008] The yellow cattle is slaughtered, and the fresh meat is segmented after maturing for 3 days in a 0-4℃ refrigerator. The beef from multiple parts of the yellow cattle is taken. Three groups of parallel samples are taken from each part. The samples are stored in a-80℃ refrigerator within 24 hours. The conventional indexes of the samples are detected.

[0009] S2, detecting the types and contents of volatile flavor substances in the samples;

[0010] The detection is carried out by using a GC-MS detection method, and solid-phase extraction of the sample is realized by using a solid-phase microextraction device;

[0011] The solid-phase microextraction device comprises a base, a heating base arranged on the base, and heating grooves arranged on the heating base in a uniform distribution;

[0012] Guide columns are arranged on both sides of the base, a screw rod driving device is arranged on the rear side of the base, a vertical screw rod is arranged on the screw rod driving device, and a controller is arranged on the front section of the base;

[0013] A sliding seat is arranged above the heating seat, and a fixed through hole matched with the heating grooves is arranged on the sliding seat;

[0014] Side ears are arranged on both sides of the sliding seat, the guide columns pass through the side ears, a support plate is arranged on the rear side of the sliding seat, and the vertical screw rod passes through the support plate and is threadedly matched with the support plate;

[0015] A transparent sealing cover is arranged on the lower end of the sliding seat, a rubber sealing ring is arranged on the upper end of the heating seat, and the sealing cover is matched with the heating seat;

[0016] An extraction head clamping device is arranged in the fixed through hole, and the extraction head clamping device comprises a fixed cylinder;

[0017] A limiting boss is arranged on the lower end of the inner cavity of the fixed cylinder, a locking bolt is arranged on one side of the upper end of the fixed cylinder, and a detachable sealing cover is arranged on the upper end of the fixed cylinder;

[0018] A temperature detection device is arranged on the extraction head clamping device in one fixed through hole of the sliding seat, the temperature detection device has an extendable probe, and the probe extends to below the sliding seat through the extraction head clamping device;

[0019] Further comprising the following steps: aging the extraction head in an environment of 250 DEG C for 2 hours; and stirring the sample beef as a detection material; accurately weighing 2-6 g of the detection material, placing the detection material in a 20 ml headspace bottle, adding 1 g of sodium chloride, and inserting the aged extraction head; extracting at 40 DEG C for 30 min;

[0020] Pulling out the extraction head in the headspace bottle and inserting it into the sample inlet of the GC-MS instrument, pyrolyzing for 5 min at 250 DEG C for detection and analysis;

[0021] S3, detection and analysis;

[0022] The nutrient substances in the detection results of the conventional indexes of the sample obtained in step S1 and the nutrient substances detected by the GC-MS instrument in step S2 are counted to form a fingerprint spectrum of the nutrient substances.

[0023] According to the result detected in step S2, the contribution of each characteristic substance to the aroma of beef is evaluated by using aroma activity value, and the evaluation standard is that the substance with OAV greater than or equal to 1 contributes to the flavor of beef; the OAV refers to the ratio of the concentration of the characteristic substance to the threshold value of the substance;

[0024] The OAV value of the aroma substance is calculated according to the threshold value and content of each characteristic substance, and the characteristic flavor substances in different parts of yellow cattle meat are screened according to the size of the OAV value; the characteristic fingerprint of the characteristic flavor substances in different parts of yellow cattle meat is obtained by counting.

[0025] Further, in step S1, each part of the sample is placed into a sampling bag;

[0026] The sampling bag comprises a sampling bag body; the upper end of the sampling bag body has an opening, and a zipper is arranged at the opening; a clamping strip is arranged below the zipper; a label insertion box is arranged on the sampling bag body.

[0027] Further, in step S2, the extraction head comprises a push rod and a sleeve;

[0028] A Z-shaped sliding groove and an observation window are arranged on the sleeve; a needle length positioning sleeve is mounted at the lower end of the sleeve; the needle length positioning sleeve is threadedly matched with the lower end of the sleeve;

[0029] The push rod is inserted into the sleeve, and a extraction head body is connected to the lower end of the push rod; the lower end of the extraction head body penetrates through the needle length positioning sleeve.

[0030] Further, the extraction head body comprises a connecting head and a limiting head;

[0031] A fiber fixing tube is arranged at the lower end of the connecting head; a diaphragm penetrating needle is arranged at the lower end of the limiting head; the connecting head is located above the limiting head; the fiber fixing tube penetrates through the limiting head and is inserted into the diaphragm penetrating needle at the lower end; the fiber fixing tube penetrates through the diaphragm penetrating needle at the lower end; a fiber coating is arranged at the lower end of the fiber fixing tube.

[0032] Further, the temperature detection device comprises a body; the body has an inner cavity, and a limiting boss is arranged at the lower end of the inner cavity; a probe is arranged in the inner cavity; a flange matched with the inner cavity is arranged at the upper end of the probe;

[0033] A sealed terminal is arranged at the upper end of the body; a spring is arranged between the sealed terminal and the probe; and the sealed terminal and the probe are electrically connected.

[0034] Specifically, in step S1, the yellow cattle are slaughtered and fresh meat is cut according to the cattle slaughtering operation procedure GB / T 19477-2004 and the cattle carcass and fresh meat cutting GB / T 27643-2011.

[0035] Specifically, in step S1, the multiple parts of the yellow cattle include tenderloin, upper brain, eye meat, outer ridge, pepper strip, chest meat, hip meat, milk dragon, beef, large cucumber strip, small cucumber strip, abdominal meat, dirty meat and beef.

[0036] Further, in step S2, the GC-MS detection conditions are as follows:

[0037] The chromatographic conditions are as follows: a DB-5MS capillary column with a specification of 30m*0.25mm*0.25μm is used;

[0038] The mode is a constant flow mode;

[0039] The temperature rising process is as follows: the initial temperature is 40℃, maintained for 15min, then increased to 160℃ at a rate of 3℃ / min, and then increased to 230℃ at a rate of 4℃ / min, maintained for 5min;

[0040] The carrier gas is high-purity nitrogen with a flow rate of 1.0mL / min;

[0041] The mass spectrometry conditions are as follows: an electron impact ion source (EI) with an electron energy of 70eV, an ion source temperature of 230℃, a transmission line temperature of 250℃, and a scanning range of 35ms~450ms.

[0042] Specifically, the routine indexes of the beef in step S1 include moisture, protein, fat, pH value, shear force, water loss rate, cooking loss, meat color, fatty acid, amino acid and cholesterol.

[0043] Further, in step S1, each part is placed into a sampling bag;

[0044] The sampling bag comprises a sampling bag body; the upper end of the sampling bag body is provided with an opening, and a zipper is arranged at the opening; a clamping strip is arranged below the zipper; and a label insertion box is arranged on the sampling bag body.

[0045] Further, the extraction head in step S2 comprises a push rod and a sleeve;

[0046] A Z-shaped sliding groove and an observation window are arranged on the sleeve; a needle length positioning sleeve is mounted at the lower end of the sleeve; and the needle length positioning sleeve is threadedly connected with the lower end of the sleeve;

[0047] The push rod is inserted into the sleeve, and a extraction head body is connected to the lower end of the push rod; and the extraction head body passes through the needle length positioning sleeve at the lower end.

[0048] Further, the extraction head body comprises a connecting head and a limiting head;

[0049] The lower end of the connecting head is provided with a fiber fixing tube; the lower end of the limiting head is provided with a diaphragm penetrating needle; the connecting head is located above the limiting head; the lower end of the fiber fixing tube is inserted into and penetrates through the diaphragm penetrating needle; and the lower end of the fiber fixing tube is provided with a fiber coating.

[0050] The method for constructing the nutritional substances and characteristic fingerprint spectrum of the yellow cattle meat can mine functional nutritional substances such as sarcosine and carnitine in the Huangping yellow cattle meat, screen out characteristic aroma compounds that contribute more to the overall flavor of the sample, and establish a characteristic flavor fingerprint spectrum of the Huangping yellow cattle meat, so that the quality characteristics and nutritional characteristic data of various yellow cattle meat can be accurately obtained, a quality characteristic and nutritional characteristic database of the yellow cattle meat is established, the precise selection of the yellow cattle breeding varieties is realized, the breeding and improvement of the yellow cattle varieties are facilitated, and the economic benefits of the breeders are facilitated.

[0051] Secondly, the method for constructing the nutritional substances and characteristic fingerprint spectrum of the yellow cattle meat adopts the solid-phase microextraction device in extraction, so that automatic extraction can be realized, multiple extractions can be simultaneously performed, the efficiency is improved, the extraction is performed in an independent environment, the influence of the external environment on the extraction process is avoided, finally, multiple comparison experiments can be performed in the same environment, and the detection accuracy is improved. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 The flow chart of the method for constructing the nutritional substances and characteristic fingerprint spectrum of the yellow cattle meat in the embodiments of the present application is shown in the figure.

[0053] Figure 2 The sampling bag structure schematic diagram in the embodiments of the present application is shown in the figure.

[0054] Figure 3 The structure schematic diagram of the extraction head in the embodiments of the present application is shown in the figure.

[0055] Figure 4 The structure schematic diagram of the extraction head body in the embodiments of the present application is shown in the figure.

[0056] Figure 5 The explosion schematic diagram of the solid-phase microextraction device in the embodiments of the present application is shown in the figure.

[0057] Figure 6 The perspective view of the solid-phase microextraction device in the embodiments of the present application is shown in the figure.

[0058] Figure 7 The front view of the solid-phase microextraction device in the embodiments of the present application is shown in the figure.

[0059] Figure 8 A-A sectional view of Figure 7 the application;

[0060] Figure 9 the application;

[0061] Figure 10 the application;

[0062] Figure 11 the application;

[0063] Figure 12 the application;

[0064] Figure 13 the application. DETAILED DESCRIPTION

[0065] The application will be further described below in conjunction with the drawings and embodiments.

[0066] As Figure 1 shown in the application, the method for constructing the nutrient substances and characteristic fingerprint spectrum of the beef cattle comprises the following steps:

[0067] S1, sample collection;

[0068] The beef cattle is slaughtered, and after maturing for 3 days in a 0-4℃ refrigerator, the beef cattle is subjected to fresh meat segmentation. Specifically, the beef cattle is slaughtered and fresh meat is segmented according to the cattle slaughtering operation procedure GB / T 19477-2004 and cattle carcass and fresh meat segmentation GB / T 27643-2011. Beef from multiple parts of the beef cattle is taken; three groups of parallel samples are taken from each part; and the samples are stored in a-80℃ refrigerator within 24 hours. Specifically, the multiple parts of the beef cattle include tenderloin, upper brain, eye meat, outer ridge, pepper strip, chest meat, hip meat, milong, cow ring, large cucumber strip, small cucumber strip, abdominal meat, dirty meat, and beef.

[0069] The conventional indexes of the samples are detected. The conventional indexes of the beef include moisture, protein, fat, pH value, shear force, water loss rate, cooking loss, meat color, fatty acid, amino acid, and cholesterol.

[0070] S2, detecting the types and contents of volatile flavor substances in the samples;

[0071] The detection is performed by using a GC-MS detection method, and solid-phase extraction of the samples is realized by using a solid-phase microextraction device 300.

[0072] The solid phase microextraction device 300 comprises a base 310, a heating base 320 arranged on the base 310, and uniformly distributed heating grooves 321 arranged on the heating base 320;

[0073] The base 310 is provided with guide columns 311 on both sides, and a lead screw driving device 330 is arranged on the rear side of the base 310, and a vertical lead screw 331 is arranged on the lead screw driving device 330; and a controller is arranged on the front section of the base 310.

[0074] A sliding seat 360 is arranged above the heating base 320, and a fixed through hole 361 matched with the heating grooves 321 is arranged on the sliding seat 360;

[0075] Side ears 362 are arranged on both sides of the sliding seat 360, and the guide columns 311 pass through the side ears 362; a support plate 363 is arranged on the rear side of the sliding seat 360, and the vertical lead screw 331 passes through the support plate 363 and is threadedly matched with the support plate 363;

[0076] A transparent sealing cover 350 is arranged on the lower end of the sliding seat 360, and a rubber sealing ring 340 is arranged on the upper end of the heating base 320; and the sealing cover 350 is matched with the heating base 320;

[0077] An extraction head clamping device 370 is arranged in the fixed through hole 361, and the extraction head clamping device 370 comprises a fixed cylinder 371;

[0078] A limiting boss is arranged on the lower end of the inner cavity of the fixed cylinder 371; a locking bolt 372 is arranged on one side of the upper end of the fixed cylinder 371; and a detachable sealing cover 373 is arranged on the upper end of the fixed cylinder 371;

[0079] A temperature detection device 380 is mounted on the extraction head clamping device 370 in one fixed through hole 361 of the sliding seat 360; the temperature detection device 380 has an extendable probe 382; and the probe 382 extends to below the sliding seat 360 through the extraction head clamping device 370.

[0080] Specifically, the temperature detection device 380 comprises a body 381; the body 381 has an inner cavity, and a limiting boss is arranged on the lower end of the inner cavity; the inner cavity is provided with the probe 382; and a flange matched with the inner cavity is arranged on the upper end of the probe 382.

[0081] A sealing terminal head 384 is arranged on the upper end of the body 381; a spring is arranged between the sealing terminal head 384 and the probe 382; and the sealing terminal head 384 is electrically connected with the probe 382.

[0082] The solid phase microextraction device 300 in the working process, the extraction head 200 is installed to the extraction head clamping device 370, the extraction head 200 is fixed through the locking bolt 372 on the upper end of the fixed cylinder 371;

[0083] When the comparative experiment is needed, a plurality of extraction heads 200 can be installed on the corresponding extraction head clamping device 370; At the same time, the headspace bottle is installed in the heating groove 210 of the heating device 200; After installation, the controller arranged in the front section of the base 310 is controlled to start the screw rod driving device 330, the screw rod driving device 330 drives the vertical screw rod 331 to rotate, thereby driving the sliding seat 360 to move downward, so that the lower end of the extraction head 200 is inserted into the headspace bottle; At the same time, the sealing cover 350 is in contact with the heating seat 320; An independent space is formed in the sealing cover 350. The push rod on the extraction head 200 is manually twisted to expose the fiber coating of the extraction head 200 in the headspace bottle; Then the headspace bottle is heated through the heating seat, so as to realize extraction.

[0084] In summary, the solid phase microextraction device 300 can facilitate automatic extraction, and multiple extractions can be performed at the same time to improve efficiency. In addition, the extraction is carried out in an independent environment to avoid the influence of the external environment on the extraction process. Finally, multiple comparative experiments can be carried out in the same environment to improve the detection accuracy.

[0085] Further comprising the following steps:

[0086] S21, using GC-MS detection method for detection, the extraction head is aged in the environment of 250 DEG C for 2 hours; And the sample beef is stirred and crushed as a detection material; 2~6g of detection material is accurately weighed and placed in a 20ml headspace bottle, 1g of sodium chloride is added, and the aged extraction head is inserted; Extraction at 40 DEG C for 30min;

[0087] Specifically, the GC-MS detection conditions are as follows:

[0088] The chromatographic conditions are as follows: DB-5MS capillary column, specifications: 30m*0.25mm*0.25um;

[0089] The mode is constant flow mode;

[0090] The temperature rising process is as follows: the initial temperature is 40 DEG C, and the temperature is kept for 15min, then the temperature is increased to 160 DEG C at the rate of 3 DEG C / min, and then the temperature is increased to 230 DEG C at the rate of 4 DEG C / min, and the temperature is kept for 5min;

[0091] Carrier gas: high-purity nitrogen; Flow rate: 1.0mL / min;

[0092] Mass spectrometry conditions; electron impact ion source (EI); electron energy 70 eV; ion source temperature 230℃; transmission line temperature 250℃; scan range 35ms~450ms.

[0093] S22, the extraction head in the headspace bottle is pulled out and inserted into the gas chromatograph-mass spectrometer inlet, and thermal desorption is performed at 250℃ for 5min for detection and analysis;

[0094] S3, detection and analysis;

[0095] The nutritional substances in the detection results of the conventional indicators of the sample obtained in step S1 and the nutritional substances detected by the mass spectrometer in step S2 are counted to form a fingerprint of the nutritional substances;

[0096] According to the results detected by the mass spectrometer in step S2, the contribution of each characteristic substance in each beef to the aroma of beef is evaluated using the aroma activity value, and the evaluation standard is that the substances with OAV greater than or equal to 1 contribute to the flavor of beef; the OAV refers to the ratio of the concentration of the characteristic substance to the threshold value of the substance;

[0097] According to the threshold value and content of each characteristic substance, the OAV value of the aroma substance is calculated, and the characteristic flavor substances in different parts of the yellow cattle meat are screened according to the size of the OAV value; the characteristic flavor substances in different parts of the yellow cattle meat are counted to obtain a characteristic fingerprint.

[0098] Embodiment

[0099] 1. Preparation of detection materials and reagents;

[0100] Select the yellow cattle that need to be detected, and the yellow cattle selected in this embodiment are 30 yellow cattle of Guizhou Huangping Nongbo Xiang Limited Liability Company raised under the same feeding conditions; the test cattle are 36-month-old healthy fattening cattle.

[0101] Main reagents: n-alkanes (chromatographic grade), slgma company, USA; 2-methyl-3-heptanone (chromatographic grade), os2 company; sodium chloride, macclin biochemical technology co., LTD.

[0102] Main equipment: GC-MS CGC-IMS) gas chromatograph-mass spectrometer, American Uranium Gold Enterprise Management Co., Ltd.; 75μm CAR / PDMS extraction head, Agilent Corporation, USA.

[0103] The solid-phase microextraction device 300 comprises a base 310, a heating base 320 arranged on the base 310, and heating grooves 321 uniformly arranged on the heating base 320.

[0104] The base 310 is provided with guiding columns 311 on both sides; the rear side of the base 310 is provided with a screw rod driving device 330; the screw rod driving device 330 is provided with a vertical screw rod 331; the front section of the base 310 is provided with a controller;

[0105] The heating seat 320 is provided with a sliding seat 360 above; the sliding seat 360 is provided with a fixed through hole 361 matched with the heating groove 321;

[0106] The sliding seat 360 is provided with side ears 362 on both sides; the guiding columns 311 pass through the side ears 362; the rear side of the sliding seat 360 is provided with a support plate 363; the vertical screw rod 331 passes through the support plate 363 and is threadedly matched with the support plate 363;

[0107] The lower end of the sliding seat 360 is provided with a transparent sealing cover 350; the upper end of the heating seat 320 is provided with a rubber sealing ring 340; the sealing cover 350 is matched with the heating seat 320;

[0108] The fixed through hole 361 is provided with an extraction head clamping device 370; the extraction head clamping device 370 comprises a fixed cylinder 371;

[0109] The lower end of the inner cavity of the fixed cylinder 371 is provided with a limiting boss; one side of the upper end of the fixed cylinder 371 is provided with a locking bolt 372; the upper end of the fixed cylinder 371 is provided with a detachable sealing cover 373;

[0110] The extraction head clamping device 370 in one fixed through hole 361 of the sliding seat 360 is installed with a temperature detecting device 380; the temperature detecting device 380 has an extendable probe 382; the probe 382 extends to the lower side of the sliding seat 360 through the extraction head clamping device 370;

[0111] The temperature detecting device 380 comprises a body 381; the body 381 has an inner cavity, the lower end of the inner cavity is provided with a limiting boss; the inner cavity is provided with the probe 382; the upper end of the probe 382 is provided with a flange matched with the inner cavity;

[0112] The upper end of the body 381 is provided with a sealing wire head 384; the sealing wire head 384 and the probe 382 are provided with a spring therebetween; and the sealing wire head 384 is electrically connected with the probe 382.

[0113] 2. The detection method is as follows:

[0114] Sample collection: 30 test cattle were slaughtered, segmented according to the cattle slaughter operation procedure (GB / T 19477-2004) and cattle carcass and fresh meat segmentation (GB / T 27643-2011), and matured for 3 days at 0~4℃ in a refrigerator. Then, 14 parts of beef, i.e. tenderloin, upper brain, eye meat, outer ridge, pepper strip, chest meat, hip meat, milk dragon, beef, big cucumber strip, small cucumber strip, abdominal meat, dirty meat, and beef, were segmented. Three groups of parallel samples were taken from each part, put into sampling bags, transported to the laboratory within 24 hours, and stored in a-80℃ refrigerator for the detection and analysis of characteristic flavor substances. The detection indexes included moisture, protein, fat, pH value, shear force, water loss rate, cooking loss, meat color, fatty acid, amino acid, cholesterol, and the types and contents of volatile flavor substances.

[0115] The detection of volatile flavor substances included the following steps:

[0116] The detection was performed by GC-MS. The extraction head was aged in an environment of 250℃ for 2 hours. The sample beef was crushed as the detection material. 2~6g of the detection material was accurately weighed, placed in a 20ml headspace bottle, 1g of sodium chloride was added, and the aged extraction head was inserted. Extraction was performed at 40℃ for 30min.

[0117] The extraction head in the headspace bottle was pulled out and inserted into the sample inlet of the GC-MS instrument. Desorption was performed at 250℃ for 5min for detection and analysis.

[0118] Specifically, the chromatographic conditions were as follows: DB-5MS capillary column with specifications of 30m*0.25mm*0.25μm was used.

[0119] The mode was constant flow mode.

[0120] The temperature rising process was as follows: the initial temperature was 40℃, maintained for 15min, then increased to 160℃ at a rate of 3℃ / min, and then increased to 230℃ at a rate of 4℃ / min, maintained for 5min.

[0121] Carrier gas: high-purity nitrogen; flow rate: 1.0mL / min.

[0122] Mass spectrometry conditions: electron impact ion source (EI); electron energy 70eV; ion source temperature 230℃; transmission line temperature 250℃; scan range 35ms~450ms.

[0123] 3. Analysis of detection results;

[0124] The nutritional substances in the detection results of the conventional indexes of the samples obtained in step 1 and the nutritional substances detected by the GC-MS instrument in step 2 were statistically analyzed to form the fingerprint of the nutritional substances.

[0125] According to the results obtained by the gas chromatograph-mass spectrometer in step 2, the contribution of each aroma substance to the aroma of beef is evaluated by using aroma activity value, and OAV is the ratio of the concentration of the aroma substance to the threshold value of the substance. It is generally believed that the substance with OAV greater than or equal to 1 contributes to the flavor of beef. The OAV value of the aroma substance is calculated according to the threshold value and content of each aroma substance to characterize the contribution of a certain aroma compound to the aroma, and the characteristic flavor substances in different parts of Huangping yellow cattle are screened to evaluate the quality of Huangping yellow cattle; the characteristic fingerprint of the characteristic flavor substances in different parts of yellow cattle is obtained by statistics.

[0126] In a feasible embodiment, in order to facilitate the sealed cryopreservation of the sample, further, in step S1, each part of the sample is placed into a sampling bag;

[0127] The sampling bag comprises a sampling bag body 100; the upper end of the sampling bag body 100 has an opening, and a zipper 110 is arranged at the opening; a clamping strip 120 is arranged below the zipper; and a label insertion box 130 is arranged on the sampling bag body 100. By arranging the clamping strip 120 and the zipper 110, the sealing of the sample after being placed into the sampling bag is facilitated, and the operation is simple.

[0128] In a feasible embodiment, in order to improve the extraction accuracy, further, in step S2, the extraction head 200 comprises a push rod 210 and a sleeve 220;

[0129] The sleeve 220 is provided with a Z-shaped sliding groove 230 and an observation window 240; a needle length positioning sleeve 250 is mounted at the lower end of the sleeve 220; and the needle length positioning sleeve 250 is threadedly connected with the lower end of the sleeve 220;

[0130] The push rod 210 is inserted into the sleeve 220, and a extraction head body 260 is connected to the lower end of the push rod 210; the extraction head body 260 passes through the needle length positioning sleeve 250 at the lower end.

[0131] The extraction head body 260 comprises a connecting head 265 and a limiting head 266; a fiber fixing tube 262 is arranged at the lower end of the connecting head 265; a diaphragm penetrating needle 261 is arranged at the lower end of the limiting head 266; the connecting head 265 is located above the limiting head 266; the fiber fixing tube 262 passes through the limiting head 266 and is inserted into and penetrates through the diaphragm penetrating needle 261 at the lower end; and a fiber coating layer 263 is arranged at the lower end of the fiber fixing tube 262.

[0132] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified, or some of the technical features can be replaced by equivalent features, by those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for constructing a fingerprint of nutrients and characteristics in beef, characterized in that: The following steps are involved: S1. Sample collection; The cattle were slaughtered and matured in a cold storage at 0-4°C for 3 days before the fresh meat was cut into pieces. Beef from multiple parts of the cattle were taken; three parallel samples were taken from each part; and the samples were stored in a refrigerator at -80°C within 24 hours. Test the routine indicators of samples; S2. Detect the types and contents of volatile flavor substances in the sample; The GC-MS detection method was used for detection, and the solid phase extraction of the sample was achieved through a solid phase microextraction device; The solid phase microextraction device comprises: a base (310); a heating base (320) is provided on the base (310); and uniformly distributed heating grooves (321) are provided on the heating base (320); Guide columns (311) are provided on both sides of the base (310); a screw drive device (330) is provided on the rear side of the base (310); a vertical screw (331) is provided on the screw drive device (330); a controller is provided at the front section of the base (310); A sliding seat (360) is provided above the heating seat (320); a fixing through hole (361) matching the heating groove (321) is provided on the sliding seat (360); Side ears (362) are provided on both sides of the sliding seat (360); the guide column (311) passes through the side ears (362); a support plate (363) is provided on the rear side of the sliding seat (360); the vertical screw rod (331) passes through the support plate (363) and is threadedly engaged with the support plate (363); A transparent sealing cover (350) is provided at the lower end of the sliding seat (360); a rubber sealing ring (340) is provided at the upper end of the heating seat (320); the sealing cover (350) matches the heating seat (320); An extraction head clamping device (370) is provided in the fixing through hole (361); the extraction head clamping device (370) comprises a fixing cylinder (371); A limiting boss is provided at the lower end of the inner cavity of the fixing cylinder (371); a locking bolt (372) is provided on one side of the upper end of the fixing cylinder (371); and a detachable sealing cover (373) is provided at the upper end of the fixing cylinder (371). A temperature detection device (380) is installed on the extraction head clamping device (370) in a fixed through hole (361) of the sliding seat (360); the temperature detection device (380) has a retractable probe (382); the probe (382) passes through the extraction head clamping device (370) and extends to the bottom of the sliding seat (360); The method also includes the following steps: aging the extraction head in an environment of 250°C for 2 hours; mincing the beef sample as a test material; accurately weighing 2-6g of the test material, placing it in a 20ml headspace vial, adding 1g of sodium chloride, and inserting the aged extraction head; extracting at 40°C for 30 minutes; Pull out the extraction head from the headspace bottle and insert it into the injection port of the gas chromatography-mass spectrometer. Perform thermal desorption at 250°C for 5 minutes for detection and analysis. S3, detection and analysis; The nutrients in the sample routine index test results obtained in step S1 and the nutrients detected by mass spectrometry in step S2 are statistically analyzed to form a nutrient fingerprint; Based on the results obtained by mass spectrometry in step S2, the contribution of each characteristic substance in each beef to the beef aroma is evaluated using aroma activity value, where the evaluation standard is that substances with an OAV greater than or equal to 1 contribute to the beef flavor; the OAV is the ratio of the concentration of the characteristic substance to the threshold value of the substance; The OAV value of the aroma substance is calculated according to the threshold and content of each characteristic substance, and the characteristic flavor substances in different parts of beef are screened out according to the size of the OAV value; the characteristic flavor substances in different parts of beef are statistically analyzed to obtain a characteristic fingerprint spectrum.

2. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 1, wherein: In step S1, the samples from each part are placed in a sampling bag; The sampling bag comprises a sampling bag body (100); the upper end of the sampling bag body (100) has an opening, and a zipper (110) is provided at the opening; a snap-fit ​​strip (120) is provided below the zipper; and a label insert box (130) is provided on the sampling bag body (100).

3. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 1, wherein: In step S2, the extraction head (200) includes a push rod (210) and a sleeve (220); The sleeve (220) is provided with a Z-shaped slide groove (230) and an observation window (240); a needle length positioning sleeve (250) is installed at the lower end of the sleeve (220); the needle length positioning sleeve (250) is threadedly engaged with the lower end of the sleeve (220); The push rod (210) is inserted into the sleeve (220), and the lower end of the push rod (210) is connected to the extraction head body (260); the lower end of the extraction head body (260) passes through the needle length positioning sleeve (250).

4. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 3, wherein: The extraction head body (260) includes a connecting head (265) and a limiting head (266); The lower end of the connector (265) is provided with a fiber fixing tube (262); the lower end of the limiting head (266) is provided with a diaphragm penetration needle (261); the connector (265) is located above the limiting head (266); the lower end of the fiber fixing tube (262) passes through the limiting head (266) and is inserted into the diaphragm penetration needle (261), and penetrates the diaphragm penetration needle (261); the lower end of the fiber fixing tube (262) is provided with a fiber coating (263).

5. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 1, wherein: The temperature detection device (380) comprises a body (381); the body (381) has an inner cavity, a limiting boss is provided at the lower end of the inner cavity; a probe (382) is provided in the inner cavity; and a flange matching the inner cavity is provided at the upper end of the probe (382); A sealing connection head (384) is provided at the upper end of the body (381); a spring is provided between the sealing connection head (384) and the probe (382); and the sealing connection head (384) and the probe (382) are electrically connected.

6. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 1, wherein: In step S1, cattle are slaughtered and their meat is cut according to the cattle slaughtering operating procedures GB / T 19477-2004 and cattle carcass and fresh meat cuts GB / T 27643-2011.

7. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 2, wherein: In step S1, the multiple parts of the yellow cattle include tenderloin, topside, eye meat, outer loin, pepper strips, brisket, rump meat, rice dragon, beef shank, large cucumber strips, small cucumber strips, belly meat, offal meat, and beef pick.

8. The method for constructing the nutritional substances and characteristic fingerprints of beef according to claim 1, wherein: In step S2, the GC-MS detection conditions are: Chromatographic conditions: DB-5MS capillary column with specifications of 30m*0.25mm*0.25μm; The mode adopts constant flow mode; The heating process was as follows: starting at 40°C, holding for 15 min, then increasing to 160°C at 3°C / min, then increasing to 230°C at 4°C / min, and holding for 5 min; Carrier gas: high-purity nitrogen; flow rate: 1.0 mL / min; Mass spectrometry conditions: electron impact ion source (EI); electron energy 70 eV; ion source temperature 230°C; transfer line temperature 250°C; scan range 35 ms–450 ms.

9. The method for constructing the nutritional substances and characteristic fingerprints in beef according to claim 1, wherein: The conventional indicators of beef in step S1 include moisture, protein, fat, pH value, shear force, water loss rate, cooking loss, meat color, fatty acids, amino acids, and cholesterol.

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