A method for judging the activity of Aspergillus niger based on the content of 1-pentadecene

Abstract

The present application relates to the technical field of detection of the activity of koji worms, and specifically to a method for judging the activity of koji worms in Daqu based on the content of 1-pentadecene, comprising the following steps: (1) weighing a Daqu sample, adding an extraction solvent to the Daqu sample for leaching, and obtaining an extract; sending the extract to a gas chromatograph-mass spectrometer to detect the content of 1-pentadecene; (2) judging the activity of koji worms in Daqu based on the content of 1-pentadecene detected in step (1). The present application can more accurately judge the activity of koji worms in Daqu samples, and can significantly shorten the time for detecting the activity of koji worms in Daqu samples.

Description

Technical Field

[0001] The present application relates to the technical field of Aspergillus niger activity detection, and in particular to a method for judging the activity of Aspergillus niger based on the content of 1-pentadecene. Background Art

[0002] Daqu is an important raw material in the winemaking process and usually needs to be stored for a certain period of time before it can be put into production. During storage, Daqu will be eaten by koji beetles. The loss caused by koji beetles can reach 10% to 20% of the total amount of Daqu. Too many koji beetles will not only reduce the weight of Daqu, but also reduce the quality of Daqu, affecting Daqu microorganisms, saccharification power, liquefaction power and other indicators. The koji beetles found in Daqu include red flour beetles, coffee bean weevils, grain borers, flat beetles, long-headed flour beetles, etc. In order to evaluate the quality of Daqu and take corresponding insect prevention measures, it is necessary to analyze the activity of Daqu koji beetles.

[0003] In the analysis of the activity of the koji worm, it can be judged according to the number of koji worms. The number of koji worms in the grain industry is mainly reflected by the number of koji worms or eggs, but it takes a long time to observe the number of koji worms. There are many commonly used methods for detecting koji eggs in the prior art, including flotation method, chitin method, staining method, etc. Among them, the flotation method has a low detection rate, the chitin detection method can only be qualitative, and the staining method is widely used in flour, but it also has certain errors.

[0004] In view of this, how to obtain a method that can accurately, quickly and conveniently judge the activity of Qu insects in Daqu is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In order to solve the above problems, the present application provides a method for judging the activity of the large-scale worm based on the content of 1-pentadecene.

[0006] The present application provides a method for judging the activity of Aspergillus niger based on the content of 1-pentadecene, which adopts the following technical solution:

[0007] A method for judging the activity of Aspergillus niger based on the content of 1-pentadecene, comprising the following steps:

[0008] (1) weighing a Daqu sample, adding an extraction solvent to the Daqu sample for leaching to obtain an extract; sending the extract to a gas chromatograph-mass spectrometer to detect the content of 1-pentadecene;

[0009] (2) judging the activity of the large-scale worm according to the 1-pentadecene content detected in the step (1).

[0010] Preferably, in step (2), judging the activity of Aspergillus niger based on the 1-pentadecene content detected in step (1) comprises:

[0011] When the measured 1-pentadecene content is in the interval of the inactive period of the Daqushi, the activity of the Daqushi is determined to be in the inactive period of the Daqushi, and the interval of the inactive period of the Daqushi is less than or equal to 1.84 mg / g;

[0012] When the measured 1-pentadecene content is in the interval of the general active period of the Daqushi, the Daqushi activity is determined to be in the general active period of the Daqushi, and the general active period of the Daqushi is in the interval of greater than 1.84 mg / g and less than or equal to 2.84 mg / g;

[0013] When the measured 1-pentadecene content is in the interval of the relatively active period of the Daqushi, the activity of the Daqushi is determined to be in the relatively active period of the Daqushi, and the interval of the relatively active period of the Daqushi is greater than 2.84 mg / g and less than or equal to 3.84 mg / g;

[0014] When the measured 1-pentadecene content is in the interval of the extremely active period of the Daqushi, the activity of the Daqushi is determined to be in the extremely active period of the Daqushi, and the interval of the extremely active period of the Daqushi is greater than 3.84 mg / g and less than or equal to 6.00 mg / g;

[0015] The interval of the inactive period of the Daquworm, the interval of the generally active period of the Daquworm, the interval of the relatively active period of the Daquworm, and the interval of the relatively active period of the Daquworm are obtained by the following method:

[0016] According to the step (1), the content of 1-pentadecene in the Daqu containing different numbers of Aspergillus niger eggs is detected, and a linear relationship is established between the content of 1-pentadecene and the corresponding number of Aspergillus niger eggs;

[0017] The activity of the Daqushima insect is divided into four levels according to the number of Daqushima insect eggs;

[0018] Obtaining the intervals corresponding to the 1-pentadecene contents of the four grades;

[0019] Preferably, the four levels are: the inactive period of the large worm, the generally active period of the large worm, the relatively active period of the large worm, and the very active period of the large worm.

[0020] Preferably, the number of eggs of the large worm in the inactive stage is less than or equal to 4000 / g; the number of eggs of the large worm in the generally active stage is greater than 4000 / g and less than or equal to 8000 / g; the number of eggs of the large worm in the relatively active stage is greater than 8000 / g and less than or equal to 12000 / g; the number of eggs of the large worm in the very active stage is greater than 12000 / g.

[0021] Preferably, in step (1), the mass of the Daqu sample weighed is 1 to 3 g;

[0022] Preferably, in step (1), the mass of the Daqu sample weighed is 1 g.

[0023] Preferably, in step (1), the extraction solvent is one or a mixture of diethyl ether, ethyl acetate, pentane and n-hexane.

[0024] Preferably, in step (1), the extraction solvent is n-hexane, and the ratio of the mass of the Daqu sample to the volume of the n-hexane is 1:(2-4);

[0025] Preferably, the ratio of the mass of the Daqu sample to the volume of the n-hexane is 1:2.

[0026] Preferably, in the step (1), adding the extraction solvent to the Daqu sample for leaching to obtain the extract comprises: adding the extraction solvent to the Daqu sample, first vortexing for 1 to 3 minutes, then ultrasonicating for 20 minutes in an ultrasonic instrument with a power of 120 W, and taking the supernatant to obtain the extract.

[0027] Preferably, in the step (1), sending the extract to a gas chromatograph-mass spectrometer to detect the 1-pentadecene content comprises: filtering the extract through a 0.22 μm filter membrane and then sending it to a gas chromatograph-mass spectrometer to detect the 1-pentadecene content.

[0028] Preferably, in step (1), the gas chromatography parameters are set as follows: the chromatographic column is HP-5 (30m×0.25mm×0.25μm), the injection port temperature is 240-260°C, the carrier gas is helium, the carrier gas flow rate is 1-3mL / min, and non-split injection is adopted;

[0029] The temperature program was as follows: the initial temperature was 40°C, maintained for 1-2 min, then heated to 130°C at 4-6°C / min, maintained for 0 min, then heated to 230°C at 25-35°C / min, maintained for 0 min;

[0030] Preferably, in step (1), the gas chromatography parameters are set as follows: the chromatographic column is HP-5 (30m×0.25mm×0.25μm), the injection port temperature is 250°C, the carrier gas is helium, the carrier gas flow rate is 1mL / min, and non-split injection is adopted;

[0031] The temperature program was as follows: the initial temperature was 40°C, maintained for 1 min, then increased to 130°C at 5°C / min, maintained for 0 min, then increased to 230°C at 30°C / min, maintained for 0 min.

[0032] Preferably, in step (1), the mass spectrometry parameters are set as follows: ion source temperature is 225-235°C, quadrupole temperature is 145-155°C, EI source is 70eV, acquisition mode is full scan, mass range is 35-500Amu, solvent delay is 3.2min;

[0033] Preferably, in step (1), the mass spectrometry parameters are set as follows: ion source temperature is 230°C, quadrupole temperature is 150°C, EI source is 70eV, acquisition mode is full scan, mass range is 35-500Amu, and solvent delay is 3.2min.

[0034] This application has the following beneficial technical effects:

[0035] (1) The present application determines the activity of the koji parasites in the Daqu samples by detecting the content of 1-pentadecene in the Daqu samples, thereby evaluating the quality of the Daqu, which can significantly shorten the time for detecting the activity of the koji parasites in the Daqu samples;

[0036] (2) The present application uses an extraction solvent to dissolve the 1-pentadecene in the Daqu sample in the extraction solvent, and then uses a gas chromatography-mass spectrometer to accurately detect the content of 1-pentadecene in the Daqu, which can more accurately judge the activity of the mold worms in the Daqu sample and improve the accuracy of the activity of the mold worms in the Daqu sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a linear curve graph of 1-pentadecene content and number of eggs in this application;

[0038] Figure 2 is a comparison chart of peak areas of different extraction solvents in Example 2;

[0039] Figure 3 is a peak area comparison diagram of different Daqu samples and n-hexane mass volume ratios in Example 3;

[0040] Figure 4 is a comparison chart of peak areas at different ultrasonic powers and ultrasonic times in Example 4;

[0041] Figure 5 is the total ion current diagram detected by HP-5 chromatographic column in Example 5;

[0042] Figure 6 This is the total ion current diagram detected using the DB-WAX UI chromatographic column in Example 5. DETAILED DESCRIPTION

[0043] The activity analysis of Daqu worms can be used to evaluate the quality of Daqu, and it is also an important basis for staff to take corresponding insect prevention measures. In the analysis of the activity of worms, it can be judged according to the number of worms. The number of worms is mainly reflected by the number of insect bodies or eggs in the grain industry, but it takes a long time to observe the number of insect bodies, and it is very easy to have a systematic error. There are many commonly used methods for detecting eggs in the prior art, including flotation, chitin method, staining method, etc., among which the detection rate of flotation method is low, the chitin detection method can only be qualitative, and the staining method is widely used in flour, but there are also certain errors. The inventor found in the study that the main worms in Daqu are red flour beetles, and the secretion of red flour beetles is 1-pentadecaene. The content of 1-pentadecaene in Daqu is detected by gas chromatography-mass spectrometry, and the condition optimization of pre-treatment and instrument parameters is realized to accurately and quantitatively analyze the content of 1-pentadecaene in Daqu. At the same time, a linear relationship was found between the 1-pentadecene content in Daqu and the activity of Daqu parasites, thus establishing a method for evaluating the activity of Daqu parasites based on the content of 1-pentadecene.

[0044] The present application is further described below with reference to embodiments.

[0045] Reagents: 1-pentadecene standard (purity ≥ 99%) was purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd.; n-butanol (analytical grade) and ethyl ether (analytical grade) were purchased from Sinopharm Chemical Reagent Co., Ltd.; methanol (chromatographic grade), ethanol (chromatographic grade) and n-hexane (chromatographic grade) were purchased from Tedia, USA; ethyl acetate (chromatographic grade) was purchased from Merck, Germany.

[0046] Instruments: Gas chromatograph-mass spectrometer (GC-MS), model 7890B GC-5977B MS, purchased from Agilent Technologies, USA; DB-WAXUI capillary chromatographic column (30m×0.25mm×0.25μm), HP-5 capillary chromatographic column (30m×0.25mm×0.25μm), purchased from Agilent Technologies, USA; Branson 3210 ultrasonic cleaner, power 120W, purchased from Bransonic Corporation, USA; CPX8800H-C ultrasonic cleaner, power 280W, purchased from Bransonic Corporation, USA.

[0047] Example 1

[0048] (1) Weighing a Daqu sample, adding an extraction solvent to the Daqu sample for leaching to obtain an extract; and sending the extract to a gas chromatograph-mass spectrometer to detect the content of 1-pentadecene.

[0049] Weigh 1g of Daqu sample into a 5mL centrifuge tube with a scale, add n-hexane into the centrifuge tube, and the ratio of the mass of Daqu sample to the volume of n-hexane is specifically selected to be 1:2, that is, the volume of n-hexane is 2mL. Vortex oscillate for 1min, then sonicate in a sonicator with a power of 120W for 20min, take the supernatant to obtain an extract, filter the extract through a 0.22μm filter membrane, and send it to a gas chromatograph-mass spectrometer for detection.

[0050] The specific gas chromatography parameters were set as follows: the chromatographic column was HP-5 (30 m × 0.25 mm × 0.25 μm), the injection port temperature was 250 °C, the carrier gas was helium, the carrier gas flow rate was 1 mL / min, and splitless injection was used;

[0051] The specific selection of programmed temperature rise is: the initial temperature is 40°C, maintained for 1 min, then heated to 130°C at 5°C / min, maintained for 0 min, then heated to 230°C at 30°C / min, maintained for 0 min.

[0052] The mass spectrometry parameters were specifically set as follows: ion source temperature of 230 °C, quadrupole temperature of 150 °C, EI source of 70 eV, acquisition mode of full scan, mass range of 35 to 500 Amu, and solvent delay of 3.2 min.

[0053] Preparation of standard solution: 1-pentadecaene standard is dissolved in n-hexane and configured into a concentration gradient of 0.128mg / L, 0.256mg / L, 0.513mg / L, 1.026mg / L, 2.051mg / L, and 4.103mg / L standard solution, and the standard solution of different concentrations is measured according to the above method. With the 1-pentadecaene peak area as the ordinate (Y), and the concentration of the standard solution as the abscissa (X), a standard curve is drawn. With the signal-to-noise ratio S / N equal to 3 as the standard, the detection limit (LOD) of detecting 1-pentadecaene in this implementation is calculated, and with the signal-to-noise ratio S / N equal to 10 as the standard, the quantitative limit (LOQ) of detecting 1-pentadecaene in this implementation is calculated, and the results are shown in Table 1.

[0054] Table 1 Standard curve parameter information

[0055]

[0056] As shown in Table 1, the correlation coefficient R 2 >0.99, indicating that within this concentration gradient, there is a good linear relationship between the peak area of ​​1-pentadecene and the concentration of the standard solution, and the standard curve can be used for the quantitative analysis of 1-pentadecene.

[0057] Evaluation of detection methods

[0058] The precision of the detection method of 1-pentadecene in Daqu of the present application was tested by relative standard deviation (RSD), and the accuracy of the detection method of 1-pentadecene in Daqu of the present application was verified by spiked recovery rate.

[0059] The method for calculating the spike recovery rate is as follows: take three Daqu samples according to the above steps, and add a certain amount of 1-pentadecene to each of the three Daqu samples; take another three Daqu samples without adding 1-pentadecene as reference samples. According to the above detection steps, detect the Daqu samples and reference samples with a certain amount of 1-pentadecene added respectively. Calculate the spike recovery rate based on the detection results.

[0060] The method for calculating the intra-day relative standard deviation is as follows: take 3 Daqu samples, and obtain extracts from the 3 Daqu samples according to the above steps respectively. The extracts are filtered through a 0.22 μm filter membrane and then sent to a gas chromatograph-mass spectrometer for detection, and the intra-day standard deviation is calculated based on the test results.

[0061] The method for calculating the inter-day relative standard deviation is as follows: take three Daqu samples, obtain extracts from the three Daqu samples according to the above steps, filter the extracts through a 0.22 μm filter membrane, store them at 4°C for one day, and then send them to a gas chromatography-mass spectrometer for detection, and calculate the inter-day standard deviation based on the detection results. The detection results are shown in Table 2.

[0062] Table 2 Accuracy and precision data

[0063]

[0064] As can be seen from Table 2, the average recovery rate of 1-pentadecaene in the present application is 100.34%, indicating that the method for detecting 1-pentadecaene in Daqu in the present application is highly accurate, the test results are reliable, and the 1-pentadecaene in Daqu can be accurately quantified, so that the activity of Daqu can be more accurately and reliably judged. The intra-day relative standard deviation is 2.98%, and the inter-day relative standard deviation is 6.43%, indicating that the method for detecting 1-pentadecaene in Daqu in the present application has good stability and small error.

[0065] (2) Determine the activity of the large-scale worm according to the 1-pentadecene content detected in the above step (1).

[0066] According to the above step (1), the content of 1-pentadecene in the Daqu containing different numbers of Aspergillus niger eggs is detected, and a linear relationship is established between the content of 1-pentadecene and the corresponding number of Aspergillus niger eggs;

[0067] The activity of the Daquworm was divided into four levels according to the number of Daquworm eggs;

[0068] Obtaining the intervals corresponding to the 1-pentadecene contents of the four levels;

[0069] There are four levels of activity of the Daqu insect: the inactive period of the Daqu insect, the generally active period of the Daqu insect, the relatively active period of the Daqu insect, and the very active period of the Daqu insect.

[0070] Specifically, according to the above step (1), the Daqu with different Daqu insect activities was detected, and it was found that the 1-pentadecaene content was significantly positively correlated with the number of insect eggs in the Daqu, thereby determining that the 1-pentadecaene substance can be used as a characteristic indicator for evaluating the activity of the Daqu insect. SPSS software was used to perform statistical analysis on the 1-pentadecaene content data in the Daqu with different numbers of insect eggs. The 1-pentadecaene content in the Daqu was used as the vertical axis (Y) and the number of insect eggs in the Daqu was used as the horizontal axis (X). A linear relationship was established, and the linear curve graph is shown in the figure below. Figure 1 As shown, the Pearson correlation coefficient is 0.967, showing a good linear relationship.

[0071] The number of eggs in the inactive period of the large Ququ worm is less than or equal to 4000 / g; the number of eggs in the generally active period of the large Ququ worm is greater than 4000 / g and less than or equal to 8000 / g; the number of eggs in the relatively active period of the large Ququ worm is greater than 8000 / g and less than or equal to 12000 / g; the number of eggs in the extremely active period of the large Ququ worm is greater than 12000 / g.

[0072] When the measured 1-pentadecene content is in the interval of the inactive period of the Daqushi, the activity of the Daqushi is determined to be in the inactive period of the Daqushi, and the interval of the inactive period of the Daqushi is less than or equal to 1.84 mg / g;

[0073] When the measured 1-pentadecene content is in the interval of the general active period of the Daqushi, the Daqushi activity is determined to be in the general active period of the Daqushi, and the general active period of the Daqushi is in the interval of greater than 1.84 mg / g and less than or equal to 2.84 mg / g;

[0074] When the measured 1-pentadecene content is in the interval of the relatively active period of the Daqushi, the activity of the Daqushi is determined to be in the relatively active period of the Daqushi, and the interval of the relatively active period of the Daqushi is greater than 2.84 mg / g and less than or equal to 3.84 mg / g;

[0075] When the measured 1-pentadecene content is in the interval belonging to the extremely active period of the Daqushima worm, the activity of the Daqushima worm is determined to be in the extremely active period of the Daqushima worm, and the interval belonging to the extremely active period of the Daqushima worm is greater than 3.84 mg / g and less than or equal to 6.00 mg / g.

[0076] When using 1-pentadecene content as a characteristic indicator for evaluating the activity of koji insects, it is necessary to accurately and reliably test the 1-pentadecene content in Daqu. The detected 1-pentadecene content can be used to accurately judge the activity of Daqu koji insects. Only then can the quality of Daqu be evaluated according to the activity of Daqu koji insects and corresponding anti-insect measures be taken.

[0077] Evaluation method validation

[0078] Two different Daqu samples were randomly selected, and the 1-pentadecene content in the Daqu samples was determined according to the above method. The activity of the koji insects in the Daqu samples was determined based on the 1-pentadecene content. The number of koji insect eggs in the Daqu samples was manually counted, and the activity of the koji insects in the Daqu samples was determined based on the number of eggs. The evaluation results of the two were compared, and the data results are shown in Table 3.

[0079] Table 3 Comparative data of Daqu sample activity verification

[0080]

[0081] As can be seen from Table 3, the activity of Daqu worms in Sample 1 determined by the content of 1-pentadecene is in the inactive stage of Daqu worms, and the result determined by counting the number of worm eggs is also in the inactive stage of Daqu worms. The activity of Daqu worms in Sample 2 determined by the content of 1-pentadecene is in the very active stage of Daqu worms, and the result determined by counting the number of worm eggs is also in the very active stage of Daqu worms. It can be seen that the accuracy of judging the activity of Daqu by the content of 1-pentadecene is consistent with the accuracy of counting the number of Daqu worm eggs. The method of judging the activity of Daqu by the content of 1-pentadecene in Daqu in this application has a higher accuracy rate.

[0082] The traditional insect counting and staining methods require more than two staff members to work together, and it takes 3 to 8 hours to judge the activity of the Daqu worms, and it is also prone to errors caused by human errors. The Daqu worm activity judgment method of the present application only requires one staff member, and the worm activity judgment of the Daqu sample can be completed within 1 hour. The present application can greatly improve work efficiency and shorten the judgment time; at the same time, it can also reduce errors and improve the accuracy of judging the worm activity.

[0083] Example 2 Investigating the effects of different extraction solvents on test results

[0084] This example is to explore the effect of different extraction solvents on the test results. The different extraction solvents include: ethanol (volume is 53%), n-butanol, ether, ethyl acetate, pentane, and n-hexane. Different extraction solvents are used to extract 1-pentadecene in Daqu, and the rest of the detection steps are the same as in Example 1. The peak area comparison of different extraction solvents is shown in the figure below. Figure 2 As shown. Figure 2It can be seen that when ethanol (vol 53%) and n-butanol are used as extraction solvents, 1-pentadecene in Daqu cannot be detected. When ether, ethyl acetate and pentane are used as extraction solvents, the peak area of ​​1-pentadecene is low, and when n-hexane is used as extraction solvent, the peak area of ​​1-pentadecene is the highest, which indicates that n-hexane is the best extraction solvent for 1-pentadecene in Daqu.

[0085] Example 3 Investigating the influence of different Daqu samples and n-hexane mass volume ratio on the test results

[0086] This example is to explore the effect of different Daqu samples and n-hexane mass volume ratios on the test results. The different Daqu samples and n-hexane mass volume ratios include: 1:2, 1:4, 1:5, 1:10, that is, the mass of n-hexane is 2mL, 4mL, 5mL, 10mL respectively. 1-Pentadene in Daqu is tested according to different Daqu samples and n-hexane mass volume ratios, and the remaining test steps are the same as in Example 1. The peak area curves of different Daqu samples and n-hexane mass volume ratios are shown in Figure 1. Figure 3 As shown, the peak area per unit volume (i.e., the peak area under g / mL) bar graph is as follows Figure 3 As shown. Figure 3 It can be seen from the curve that as the mass volume ratio of Daqu sample to n-hexane increases, the concentration of 1-pentadecene is diluted and the peak area of ​​1-pentadecene gradually decreases. From the bar graph, it can be seen that when the mass volume ratio of Daqu sample to n-hexane is 1:4 and 1:10, the peak area per unit volume of 1-pentadecene is the highest, which indicates that when the mass volume ratio of Daqu sample to n-hexane is 1:4 or 1:10, the extraction effect of 1-pentadecene in Daqu sample is the best. Because the content of target compounds in Daqu is low, in order to improve the detection limit, quantitative accuracy, economy and environmental protection of the method, the mass volume ratio of Daqu sample to n-hexane is 1:2 as the optimal choice.

[0087] Example 4 Investigating the effects of different ultrasonic powers and ultrasonic times on the test results

[0088] In this example, in order to explore the influence of different ultrasonic powers and ultrasonic times on the detection results, a 120W ultrasonic instrument was used to ultrasonically process the Daqu sample for 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 30 minutes, respectively, to detect the 1-pentadecene content in the Daqu at different ultrasonic times. A 280W ultrasonic instrument was used to ultrasonically process the Daqu sample for 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 30 minutes, respectively, to detect the 1-pentadecene content in the Daqu at different ultrasonic times. The detection results of the two ultrasonic instruments with different ultrasonic powers for ultrasonicating the Daqu sample for 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 30 minutes are shown as follows: Figure 4As shown in the figure, it can be seen that the peak area of ​​1-pentadecene does not change significantly under different ultrasonic time conditions using a 280W ultrasonic instrument, but the peak area of ​​1-pentadecene is significantly higher when the ultrasonic instrument is used for 20 minutes at 120W ultrasonic. The peak area of ​​1-pentadecene is significantly higher than the peak area of ​​other ultrasonic times. This shows that by using ultrasonic instruments of different powers and adjusting the ultrasonic time, the detection effect of 1-pentadecene in Daqu can be significantly increased, making the detection results more accurate.

[0089] Example 5 Investigating the effects of different chromatographic columns on the test results

[0090] This example is to explore the effect of different chromatographic columns on the detection results. The different chromatographic columns include: non-polar column (HP-5) and polar column (DB-WAX UI). The chromatographic column parameters of both are 30m×0.25mm×0.25μm. The total ion current diagram detected by HP-5 chromatographic column is as follows: Figure 5 The total ion current detected by DB-WAX UI column is shown in Figure 6 As shown. Combined Figure 5 and Figure 6 It can be seen that both the HP-5 column and the DB-WAX UI column can achieve good separation of 1-pentadecene, but when the HP-5 column is used, the response of 1-pentadecene is higher and there are fewer impurity peaks, which has a better detection effect on 1-pentadecene in Daqu.

[0091] The present application establishes a detection method for 1-pentadecene in Daqu with higher accuracy and better detection effect by optimizing various experimental conditions and parameters when detecting 1-pentadecene in Daqu. The method is used to detect the content of 1-pentadecene in Daqu, and then the activity of Daqu is judged by the content of 1-pentadecene in Daqu. This method can more accurately judge the activity of the mold parasites in Daqu samples, and at the same time can greatly shorten the time for detecting the activity of the mold parasites in Daqu samples.

[0092] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for judging the activity of Aspergillus niger based on the content of 1-pentadecene, characterized in that: The following steps are involved: (1) Weighing a Daqu sample, adding an extraction solvent to the Daqu sample, vortexing for 1 to 3 minutes, and then sonicating in a 120 W ultrasonic instrument for 20 minutes, taking the supernatant to obtain an extract; sending the extract to a gas chromatography-mass spectrometer to detect the content of 1-pentadecene; (2) judging the activity of the large-scale worm according to the 1-pentadecene content detected in step (1); Wherein, in the step (1), the extraction solvent is n-hexane, and the ratio of the mass of the Daqu sample to the volume of the n-hexane is 1:(2-4); In the step (1), the gas chromatography parameters are set as follows: the chromatographic column is HP-5, 30m×0.25mm×0.25μm, the injection port temperature is 240-260°C, the carrier gas is helium, the carrier gas flow rate is 1-3 mL / min, and non-split injection is adopted; the programmed temperature is as follows: the initial temperature is 40°C, maintained for 1-2 min, then heated to 130°C at 4-6°C / min, maintained for 0 min, then heated to 230°C at 25-35°C / min, maintained for 0 min; the mass spectrometry parameters are set as follows: the ion source temperature is 225-235°C, the quadrupole temperature is 145-155°C, the EI source is 70 eV, the acquisition mode is full scan, the mass range is 35-500 Amu, and the solvent delay is 3.2 min; The step of judging the activity of the 1-pentadecene according to the content of 1-pentadecene detected in step (1) comprises: When the measured 1-pentadecene content is in the interval of the inactive period of the Daqushi, the activity of the Daqushi is determined to be in the inactive period of the Daqushi, and the interval of the inactive period of the Daqushi is less than or equal to 1.84 mg / g; When the measured 1-pentadecene content is in the interval of the general active period of the Daqushi, the Daqushi activity is determined to be in the general active period of the Daqushi, and the general active period of the Daqushi is greater than 1.84 mg / g and less than or equal to 2.84 mg / g; When the measured 1-pentadecene content is in the interval of the relatively active period of the Daqushi, the activity of the Daqushi is determined to be in the relatively active period of the Daqushi, and the interval of the relatively active period of the Daqushi is greater than 2.84 mg / g and less than or equal to 3.84 mg / g; When the measured 1-pentadecene content is in the interval belonging to the extremely active period of the Daqushima worm, the activity of the Daqushima worm is determined to be in the extremely active period of the Daqushima worm, and the interval belonging to the extremely active period of the Daqushima worm is greater than 3.84 mg / g and less than or equal to 6.00 mg / g.

2. The method according to claim 1, characterized in that The intervals of the inactive period of the Daquzi insect, the intervals of the generally active period of the Daquzi insect, the intervals of the relatively active period of the Daquzi insect, and the intervals of the very active period of the Daquzi insect are obtained by the following method: According to the step (1), the content of 1-pentadecene in the Daqu containing different numbers of Aspergillus niger eggs is detected, and a linear relationship is established between the content of 1-pentadecene and the corresponding number of Aspergillus niger eggs; The activity of the Daqushima insect is divided into four levels according to the number of Daqushima insect eggs; Obtaining the intervals corresponding to the 1-pentadecene contents of the four grades; The four levels are: the inactive period of the large worm, the generally active period of the large worm, the relatively active period of the large worm, and the very active period of the large worm.

3. The method according to claim 2, characterized in that The number of eggs of the large worm in the inactive stage is less than or equal to 4000 / g; the number of eggs of the large worm in the generally active stage is greater than 4000 / g and less than or equal to 8000 / g; the number of eggs of the large worm in the relatively active stage is greater than 8000 / g and less than or equal to 12000 / g; the number of eggs of the large worm in the very active stage is greater than 12000 / g.

4. The method according to claim 1, characterized in that: In the step (1), the mass of the Daqu sample weighed is 1 to 3 g.

5. The method according to claim 1, characterized in that In the step (1), the mass of the Daqu sample weighed is 1 g.

6. The method according to claim 1, characterized in that The ratio of the mass of the Daqu sample to the volume of the n-hexane is 1:

2.

7. The method according to claim 1, characterized in that In the step (1), sending the extract to a gas chromatograph-mass spectrometer to detect the content of 1-pentadecene comprises: filtering the extract through a 0.22 μm filter membrane and then sending the extract to a gas chromatograph-mass spectrometer to detect the content of 1-pentadecene.

8. The method according to claim 1, characterized in that In the step (1), the gas chromatography parameters are set as follows: the chromatographic column is HP-5, 30m×0.25mm×0.25μm, the injection port temperature is 250°C, the carrier gas is helium, the carrier gas flow rate is 1mL / min, and non-split injection is adopted; The temperature program was as follows: initial temperature was 40°C, maintained for 1 min, then heated to 130°C at 5°C / min, maintained for 0 min, then heated to 230°C at 30°C / min, maintained for 0 min.

9. The method according to claim 1, characterized in that In the step (1), the mass spectrometry parameters are set as follows: ion source temperature is 230°C, quadrupole temperature is 150°C, EI source is 70 eV, acquisition mode is full scan, mass range is 35-500 Amu, and solvent delay is 3.2 min.

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