A method for identifying different types of demolition songs

Abstract

The present application relates to the technical field of winemaking, and in particular to a method for identifying different types of shaicangqu, comprising the following steps: (1) taking a daqu sample, adding a solvent to the daqu sample for extraction to obtain a daqu extract; (2) detecting the pH value and melanoidin concentration of the daqu extract; (3) identifying the type of the daqu sample according to the pH value and melanoidin concentration of the daqu extract. The present application can improve the accuracy of identifying the type of daqu, and can also reduce the detection time, use cost and energy consumption.

Description

Technical Field

[0001] The present application relates to the technical field of wine making, and in particular to a method for identifying different types of kaikan qu. Background Art

[0002] The "three highs and one long" process is the most critical in the production process of Maotai-flavor liquor, namely high-temperature koji making, high-temperature fermentation, and high-temperature distillation. Koji making is an important step in the brewing process of Maotai-flavor liquor. The Daqu obtained by koji making provides saccharification and fermentation, the source of enzymes for aroma production, and the precursor of aroma for the winemaking process. According to the different appearance colors of the Daqu that is unloaded after fermentation, it is divided into three types of Daqu: white koji, yellow koji, and black koji. Different Daqu have different roles in the fermentation and winemaking process, and have a certain impact on the taste and flavor of the brewed liquor. Therefore, it is necessary to identify the Daqu that has been unloaded in order to choose the right type of Daqu for winemaking.

[0003] In the existing technology, there are methods such as DNA sequencing and fingerprinting to determine the quality of Daqu. However, whether it is DNA sequencing or fingerprinting, the detection method has a large workload, the detection instrument is expensive, resulting in high detection and maintenance costs, the detection method is complex, and the accuracy is low. Therefore, it is necessary to find a new method to identify the type of Daqu. Summary of the invention

[0004] In order to solve the above problems, the present application provides a method for identifying different types of demolition songs.

[0005] The present application provides a method for identifying different types of demolition songs using the following technical solution:

[0006] A method for identifying different types of demolition songs, comprising the following steps:

[0007] (1) taking a Daqu sample, and adding a solvent to the Daqu sample to obtain a Daqu extract;

[0008] (2) detecting the pH value and melanoidin concentration of the Daqu extract;

[0009] (3) Identifying the type of the Daqu sample based on the pH value and melanoidin concentration of the Daqu extract.

[0010] Preferably, in step (3), identifying the type of the Daqu sample according to the pH value and melanoidin concentration of the Daqu extract comprises:

[0011] When the pH value of the Daqu extract is within the interval to which the pH value of Baiqu belongs, and / or the melanoidin concentration of the Daqu extract is within the interval to which the melanoidin concentration of Baiqu belongs, the Daqu sample is determined to be Baiqu;

[0012] When the pH value of the Daqu extract is within the interval of the pH value of Huangqu, and / or the melanoidin concentration of the Daqu extract is within the interval of the melanoidin concentration of Huangqu, the Daqu sample is determined to be Huangqu;

[0013] When the pH value of the Daqu extract is within the interval to which the pH value of Heiqu belongs, and / or the melanoidin concentration of the Daqu extract is within the interval to which the melanoidin concentration of Heiqu belongs, the Daqu sample is determined to be Heiqu.

[0014] Preferably, the intervals to which the pH value of white koji belongs, the intervals to which the melanin concentration of white koji belongs, the intervals to which the pH value of yellow koji belongs, the intervals to which the melanin concentration of yellow koji belongs, the intervals to which the pH value of black koji belongs, and the intervals to which the melanin concentration of black koji belongs are defined as follows:

[0015] Take white, yellow and black koji as Daqu determination samples respectively, wherein the Daqu determination samples are determined by sensory evaluation;

[0016] Calculating the average pH value and standard deviation of the Daqu determination samples of the white, yellow and black koji, as well as the average melanoidin concentration and standard deviation, respectively, wherein the pH value and the melanoidin concentration are obtained by the steps (1) and (2);

[0017] The pH value intervals and the melanoidin concentration intervals of the white koji, yellow koji and black koji are determined respectively according to the average value and the standard deviation.

[0018] Preferably, the pH value of the white koji belongs to a range greater than or equal to 6.75, and the melanin concentration of the white koji belongs to a range less than or equal to 1.65 mmol / L;

[0019] The pH value of the yellow koji is in the range of 5.95 to 6.75, and the concentration of the yellow koji melanoidin is in the range of 1.65 to 2.40 mmol / L;

[0020] The pH value of the black koji belongs to a range less than or equal to 5.95, and the concentration of the black koji melanoidin belongs to a range greater than or equal to 2.40 mmol / L.

[0021] Preferably, the method of identifying the type of the Daqu sample according to the pH value and melanoidin concentration of the Daqu extract further comprises:

[0022] When the type of Daqu determined by the pH value of the Daqu extract is inconsistent with the type of Daqu determined by the melanoidin concentration of the Daqu extract,

[0023] The pH value of the Daqu extract is subtracted from the average pH value of the Daqu type determined by the pH value to obtain a difference, and the absolute value of the difference is divided by the pH standard deviation to obtain a pH standard deviation ratio;

[0024] The melanin concentration of the Daqu extract is subtracted from the average melanin concentration of the Daqu type determined by the melanin concentration to obtain a difference, and the absolute value of the difference is divided by the melanin concentration standard deviation to obtain a melanin concentration standard deviation ratio;

[0025] If the pH value standard deviation ratio is less than the melanoidin concentration standard deviation ratio, identifying the type of the Daqu sample according to the pH value;

[0026] If the pH value standard deviation ratio is greater than or equal to the melanoidin concentration standard deviation ratio, the type of the Daqu sample is identified based on the melanoidin concentration.

[0027] Preferably, the mass of the Daqu sample is 1 to 3 g;

[0028] Preferably, the mass of the Daqu sample is 2 g.

[0029] Preferably, in step (1), adding a solvent to the Daqu sample to obtain a Daqu extract comprises: when detecting the pH value of the Daqu extract, adding distilled water to the Daqu sample, first ultrasonicating for 25 to 35 minutes, then centrifuging for 8 to 12 minutes, with a centrifugal speed of 7500 to 8500 r / min, repeating the ultrasonic and centrifugal steps once, extracting the supernatant to obtain a Daqu extract;

[0030] Preferably, in the step (1), when the pH value of the Daqu extract is detected, adding a solvent to the Daqu sample to obtain the Daqu extract comprises: adding distilled water to the Daqu sample, first ultrasonicating for 30 minutes, then centrifuging for 10 minutes at a centrifugal speed of 8000 r / min, repeating the ultrasonicating and centrifuging steps once, extracting the supernatant to obtain the Daqu extract.

[0031] Preferably, the ratio of the mass of the Daqu sample to the volume of the distilled water is 1:(9-11);

[0032] Preferably, the ratio of the mass of the Daqu sample to the volume of the distilled water is 1:10.

[0033] Preferably, in the step (1), when the melanoidin concentration of the Daqu extract is detected, adding a solvent to the Daqu sample to obtain the Daqu extract comprises: adding a 40% ethanol solution to the Daqu sample, soaking it at 70°C for 2.5 to 3.5 hours, and then centrifuging it for 8 to 12 minutes at a centrifugal speed of 7500 to 8500 r / min, repeating the soaking and centrifugation steps once, and extracting the supernatant to obtain the Daqu extract;

[0034] Preferably, in the step (1), when the melanoidin concentration of the Daqu extract is detected, adding a solvent to the Daqu sample to obtain the Daqu extract comprises: adding a 40% ethanol solution to the Daqu sample, soaking it at 70°C for 3 hours, centrifuging it for 10 minutes at a centrifugal speed of 8000 r / min, repeating the soaking and centrifuging steps once, extracting the supernatant, and obtaining the Daqu extract;

[0035] Preferably, the ratio of the mass of the Daqu sample to the volume of the ethanol solution is 1:(16.5-18.5);

[0036] More preferably, the ratio of the mass of the Daqu sample to the volume of the ethanol solution is 1:17.5.

[0037] Preferably, in the step (2), detecting the melanoidin concentration of the Daqu extract comprises: detecting the absorbance of the Daqu extract at a wavelength of 470 nm, and then calculating the melanoidin concentration according to the Lambert-Beer law formula.

[0038] This application has the following beneficial technical effects:

[0039] 1. The present application determines the sample through Daqu and calculates the pH value and melanin concentration range corresponding to Baiqu, Huangqu and Heiqu. When the pH value and / or melanin concentration of the detected Daqu sample are within the range of the corresponding type of Daqu, it can be determined what kind of Daqu the Daqu is. The two different types of determination indicators are combined to jointly identify the unknown Daqu types, thereby improving the accuracy of identifying the types of Daqu. At the same time, the identification indicators of the present application are pH value and melanin concentration. The detection method is simple and fast, which can greatly reduce the time for identifying Daqu. In addition, the detection instrument is simple, which greatly reduces the cost of using the instrument, and is suitable for identifying large quantities of Daqu on the production line.

[0040] 2. The present application adjusts the ratio of the distilled water volume to the Daqu mass, the supernatation time, the centrifugation speed and the centrifugation time in the Daqu pH test so that the interval ranges between different types of Daqu do not overlap, thereby being able to use the pH value to identify the type of Daqu. DETAILED DESCRIPTION

[0041] At present, there are two methods for identifying Daqu after unpacking. The existing technology includes identification based on Daqu fingerprint spectrum and identification based on Daqu thermal enthalpy value. However, the instruments used in these methods are relatively expensive, with high maintenance costs, and the pre-treatment is also relatively complicated, resulting in a long time for identifying Daqu and a low accuracy rate. It is not suitable for the identification of large quantities of Daqu on the brewing production line. The inventor found in the study that by combining the two indicators of Daqu pH value and melanoidin concentration, the type of Daqu can be effectively identified with a high accuracy rate.

[0042] The present application is further described below with reference to embodiments.

[0043] A method for identifying different types of demolition songs, comprising the following steps:

[0044] (1) taking a Daqu sample, and adding a solvent to the Daqu sample to obtain a Daqu extract.

[0045] Specifically, samples are taken from the four corners and the middle of each dismantled Daqu brick, mixed, and passed through a 60-mesh sieve and then dried to obtain a Daqu sample. 1 to 3 g of the Daqu sample is accurately weighed. In this application, 2 g of the Daqu sample is specifically weighed and placed in a centrifuge tube.

[0046] When detecting the pH value of the Daqu extract, the solvent is distilled water, and distilled water is added to the Daqu sample. The ratio of the Daqu sample mass to the distilled water volume is 1: (9-11). In the present application, the ratio of the Daqu sample mass to the distilled water volume is specifically selected as 1: 10, that is, the amount of distilled water added is 20 mL. The centrifuge tube is placed in an ultrasonic cleaner for 25-35 minutes, the ultrasonic frequency is 40KHz, the ultrasonic temperature is 25°C, and then centrifuged for 8-12 minutes, and the centrifugal speed is 7500-8500 r / min. In the present application, it is specifically selected to be ultrasonic for 30 minutes, then centrifuged for 10 minutes, and the centrifugal speed is 8000 r / min. After repeating the ultrasonic and centrifugal steps once, the supernatant is extracted to obtain the Daqu extract for detecting the pH value.

[0047] When detecting the melanin concentration of the Daqu extract, the solvent is selected as a 40% ethanol solution, and a 40% ethanol solution is added to the Daqu sample, the ratio of the Daqu sample mass to the ethanol solution volume is 1: (16.5-18.5), and the ratio of the Daqu sample mass to the ethanol solution volume in the present application is specifically selected as 1: 17.5, that is, the volume of the added ethanol solution is 35mL; the mixture of the Daqu sample and the ethanol solution is soaked at 70°C for 2.5-3.5h, and the present application specifically selects soaking at 70°C for 3h, and then centrifuged for 8-12min, and the centrifugal speed is 7500-8500r / min, and the present application specifically selects centrifugation for 10min, and the centrifugal speed is 8000r / min; after repeating the soaking and centrifugation steps once more, the supernatant is extracted to obtain the Daqu extract for detecting the melanin concentration.

[0048] (2) Detect the pH value and melanin concentration of the Daqu extract.

[0049] Specifically, when detecting the pH value of the Daqu extract, a pH meter is used to measure the Daqu extract used for detecting the pH value to obtain the pH value.

[0050] When detecting the melanoidin concentration of the Daqu extract, the Daqu extract obtained above for detecting the melanoidin concentration is added to a 50 mL volumetric flask, fixed to volume with distilled water, and then distilled water is used as a blank solution. The absorbance is measured at 470 nm using a spectrophotometer, and then the melanoidin concentration is calculated using the Lambert-Beer law formula, the formula is: C=A / eL, wherein C is the melanoidin concentration (mmol / L), A is the absorbance of the melanoidin extract at 470 nm, e is the molar extinction coefficient of the melanin (0.64L / mmol*cm), and L is the absorption thickness in cm.

[0051] (3) Identifying the type of the Daqu sample based on the pH value and melanoidin concentration of the Daqu extract.

[0052] Specifically, the Daqu determination samples determined as white koji, yellow koji, and black koji by sensory evaluation are taken, and the Daqu determination samples include 30 white koji Daqu determination samples, 30 yellow koji determination samples, and 40 black koji determination samples. All Daqu determination samples are subjected to the above steps (1) and (2) to obtain the pH values ​​and melanoidin concentrations of all Daqu determination samples, and the average values ​​of the pH values ​​and melanoidin concentrations of the white koji, yellow koji, and black koji in the Daqu determination samples are calculated, and the corresponding standard deviations are calculated, and then the pH value intervals and melanoidin concentration intervals of the white koji, yellow koji, and black koji are determined according to the average values ​​and standard deviations. The pH values ​​of the white koji, yellow koji, and black koji determination samples are shown in Table 1, and the melanoidin concentrations are shown in Table 2.

[0053] Table 1 pH values ​​of white koji, yellow koji and black koji

[0054]

[0055]

[0056]

[0057] According to the pH value data of white koji, yellow koji and black koji in Table 1, the highest and lowest pH values ​​in white koji are removed, and the average pH value of white koji is calculated to be 7.02, with a standard deviation of 0.27. According to the data, the range of white koji should be 7.02±0.27, that is, 6.75-7.29. However, after overall data analysis, since the pH value of white koji is generally higher than that of yellow koji and black koji, the pH value range of white koji is determined to be greater than or equal to 6.75 (≥6.75). After removing the highest and lowest pH values ​​in black koji, the average pH value of black koji is calculated to be 5.76, with a standard deviation of 0.19. According to the data, the range of black koji should be 5.76±0.19, that is, 5.57-5.95. However, since the pH value of black koji is generally lower than that of yellow koji and white koji, the pH value range of black koji is determined to be less than or equal to 5.95 (≤5.95). After removing the highest and lowest pH values ​​in yellow koji, the average pH value of yellow koji is calculated to be 6.28, with a standard deviation of 0.26. According to the data, the interval range of black koji should be 6.28±0.26, that is, 6.02-6.54. However, when analyzing all the data, the pH value of some data of yellow koji is lower than or exceeds this range. Therefore, the range of yellow koji is limited by the lowest pH value of white koji and the highest pH value of black koji. Finally, the pH value interval of yellow koji is determined to be 5.95-6.75, excluding the two endpoints of 5.95 and 6.75. The accuracy of identifying white koji, yellow koji, and black koji in this application can be improved by corresponding processing of the interval range of the type to which Daqu belongs.

[0058] From the calculation range of the three types of Daqu, there is no overlap in the range of the three types of Daqu, which means that the detection method in this scheme can distinguish white qu, yellow qu and black qu by pH value.

[0059] Table 2 Melanoidin concentration values ​​of white, yellow and black koji

[0060]

[0061]

[0062]

[0063] According to the melanin concentration data of white koji, yellow koji and black koji in Table 2, the highest and lowest melanin concentrations in white koji were removed, and the melanin concentration of white koji was calculated to be 1.30 mmol / L, with a standard deviation of 0.35 mmol / L. According to the data, the range of white koji should be 1.30±0.35 mmol / L, that is, 0.95-1.65 mmol / L. However, after an overall analysis of all the data, since the melanin concentration of white koji is generally lower than that of yellow koji and black koji, the melanin concentration range of white koji is determined to be less than or equal to 1.65 (≤1.65) mmol / L. After removing the highest and lowest values ​​of the melanin concentration of Huangqu, the average melanin concentration of Huangqu was calculated to be 2.18mmol / L, and the standard deviation was 0.22mmol / L. According to the data, the interval of Huangqu should be 2.18±0.22mmol / L, that is, 1.96~2.40mmol / L. However, after analyzing the data, since some data of the melanin concentration of Huangqu were lower than 1.96mmol / L, the melanin concentration interval of Huangqu was determined to be 1.65~2.40mmol / L, excluding the two endpoint values ​​of 1.65mmol / L and 2.40mmol / L. After removing the highest and lowest values ​​of the melanin concentration in the black koji, the average melanin concentration of the black koji was calculated to be 2.95mmol / L, with a standard deviation of 0.36mmol / L. According to the data, the interval range of the black koji should be 2.95±0.36mmol / L, that is, 2.59-3.31mmol / L. When analyzing all the data, some data of the melanin concentration of the black koji were lower than 2.59mmol / L, and the melanin concentration of the black koji was generally higher than that of the yellow koji and the white koji. Therefore, the interval range of the black koji was determined to be greater than or equal to 2.4 (≥2.4)mmol / L. Through the corresponding processing of the interval range of the type to which the large koji belongs, the accuracy of identifying the white koji, the yellow koji, and the black koji in this application can be improved.

[0064] From the calculation range of the three types of Daqu, there is no overlap in the range of the three types of Daqu, which means that the detection method in this scheme can distinguish white qu, yellow qu and black qu by melanin concentration.

[0065] When the pH value of the Daqu extract is in the interval of Baiqu (≥6.75) and the melanin concentration of the Daqu extract is in the interval of Baiqu (≤1.65mmol / L), the Daqu sample is judged to be Baiqu; when the pH value of the Daqu extract is in the interval of Huangqu (5.95-6.75) and the melanin concentration of the Daqu extract is in the interval of Huangqu (1.65-2.40mmol / L), the Daqu sample is judged to be Huangqu; when the pH value of the Daqu extract is in the interval of Heiqu (≤5.95) and the melanin concentration of the Daqu extract is in the interval of Heiqu (≥2.4mmol / L), the Daqu sample is judged to be Heiqu.

[0066] When the type of Daqu determined by the pH value of the Daqu extract is inconsistent with the type of Daqu determined by the melanin concentration of the Daqu extract, that is, the determination result using the pH value determination index is different from the determination result using the melanin concentration determination index, the following method is used to determine which specific index is used for the final determination.

[0067] The pH value of the Daqu extract is subtracted from the average pH value of the Daqu type determined by the pH value to obtain a difference, and the absolute value of the difference is divided by the standard deviation of the pH value of the Daqu type determined by the pH value to obtain a pH standard deviation ratio; the melanin concentration of the Daqu extract is subtracted from the average melanin concentration of the Daqu type determined by this melanin concentration to obtain a difference, and the absolute value of the difference is divided by the standard deviation of the melanin concentration of the Daqu type determined by this melanin concentration to obtain a melanin concentration standard deviation ratio. If the pH standard deviation ratio is less than the melanin concentration standard deviation ratio, the Daqu type is identified by the pH value of the Daqu extract; if the pH standard deviation ratio is greater than or equal to the melanin concentration standard deviation ratio (that is, the melanin concentration standard deviation ratio is less than or equal to the pH standard deviation ratio), the Daqu type is identified by the melanin concentration of the Daqu extract.

[0068] Method validation

[0069] Daqu samples were taken that were determined to be yellow koji, white koji, and black koji through sensory evaluation. The Daqu samples included 10 white koji samples, 10 yellow koji samples, and 10 black koji samples. The Daqu samples were identified according to the above-mentioned method for identifying white koji, yellow koji, and black koji. The pH value test results of the Daqu samples are shown in Table 3, and the melanoidin concentrations of the Daqu samples are shown in Table 4.

[0070] Table 3 pH values ​​of Daqu samples

[0071]

[0072]

[0073] According to the test results in Table 3, using pH value alone as an indicator for identifying white koji, yellow koji and black koji, the pH values ​​of white koji 1, white koji 5 and white koji 8 in the white koji are not within the white koji interval; the pH values ​​of yellow koji 2, yellow koji 3, yellow koji 7 and yellow koji 10 in the yellow koji are not within the yellow koji interval; and the pH values ​​of black koji 3 and black koji 6 in the black koji are not within the black koji interval. That is, using pH alone as an identification indicator, the accuracy rate is 21 / 30, which is 70%.

[0074] Table 4 Melanoidin concentration values ​​of Daqu samples

[0075]

[0076] According to the test results in Table 4, using melanoidin concentration alone as an indicator for identifying white, yellow and black koji, the melanoidin concentrations of white koji 1 and white koji 2 in the white koji are not within the white koji interval; yellow koji 3, yellow koji 4, yellow koji 6 and yellow koji 9 in the yellow koji are not within the yellow koji interval; and black koji 9 in the black koji is not within the black koji interval. That is, using melanoidin concentration alone as an identification indicator, the accuracy rate is 23 / 30, which is 77%.

[0077] Combining Table 3 and Table 4, it can be seen that the pH value and melanin concentration of Baiqu 1 are both in the interval of Huangqu. Although the results of the two determination indicators are consistent, the Daqu is actually Baiqu, so the determination of Baiqu 1 is wrong. The pH value and melanin concentration of Huangqu 3 are both in the interval of Baiqu. Although the results of the two determination indicators are consistent, the Daqu is actually Huangqu, so the determination of Huangqu 3 is wrong.

[0078] Baiqu 2, Baiqu 5, Baiqu 8, Huangqu 2, Huangqu 4, Huangqu 6, Huangqu 7, Huangqu 9, Huangqu 10, Heiqu 3, Heiqu 6, Heiqu 9, these Daqu are Daqu samples whose pH value determination results are different from the melanin determination results. According to the above method of different pH value determination results from melanin determination results, calculate the pH value standard deviation ratio and melanin concentration standard deviation ratio. Taking Baiqu 2 as an example, the pH value of Baiqu 2 is in the interval of the pH value of Baiqu, that is, the pH value of Baiqu 2 determines that Baiqu 2 is Baiqu, but its melanin concentration is in the interval of the melanin concentration of Huangqu, that is, the melanin concentration of Baiqu 2 determines that Baiqu 2 is Huangqu. The method for calculating the pH value standard deviation ratio of Baiqu 2 is to subtract the average pH value of Baiqu from the pH value of Baiqu 2 to obtain the difference, and then divide the absolute value of the difference by the standard deviation of Baiqu to obtain the pH value standard deviation ratio of Baiqu 2. The calculation method of the standard deviation ratio of the melanoidin concentration of Baiqu 2 is to subtract the average melanoidin concentration of Huangqu from the melanoidin concentration of Baiqu 2 to obtain the difference, and then divide the absolute value of the difference by the standard deviation of Huangqu to obtain the standard deviation ratio of the melanoidin concentration of Baiqu 2. The results of the standard deviation ratio of pH value and the standard deviation ratio of melanoidin concentration of Daqu samples with different determination results are shown in Table 5.

[0079] Table 5 pH value standard deviation ratio and melanoidin concentration standard deviation ratio

[0080]

[0081]

[0082] It can be seen from Table 5 that the standard deviation ratio of pH value of Huangqu 10 is less than the standard deviation ratio of melanoidin concentration, that is, based on the pH value of Huangqu 10, Huangqu 10 is judged as black koji according to the pH value, and the judgment result is wrong. The judgment results of the other Daqu according to the above judgment method are correct.

[0083] That is, among the 30 Daqu samples used for verification, Baiqu 1, Huangqu 3, and Huangqu 10 were judged incorrectly, and the judgment results of the remaining Daqu were consistent with the actual Daqu types. That is, the accuracy of the 30 Daqu samples is 27 / 30, which is 90%. It can be seen that in this application, two identification indicators (pH value and melanoidin concentration) are used together as indicators for identifying Daqu, which can greatly improve the accuracy of identifying Daqu types; at the same time, the identification indicators of this application are pH value and melanoidin concentration, and the detection method is simple and fast, which can greatly reduce the time for identifying Daqu, and the detection instrument is simple, which greatly reduces the cost of using the instrument, and is suitable for identifying large quantities of Daqu on the production line.

[0084] Example 1 Influence of the ratio of distilled water volume to Daqu mass on Daqu identification results

[0085] Take the Daqu samples that have been determined as white, yellow and black qu through sensory evaluation, take samples from the four corners and the middle of each Daqu brick, mix them, pass them through a 60-mesh sieve, and then dry them to obtain the Daqu samples, accurately weigh 2 g of the Daqu samples, and put the Daqu samples into a centrifuge tube.

[0086] Distilled water was added to the Daqu sample, and the ratio of the volume of distilled water (mL) to the mass of the Daqu sample (g) was 5, 10, 15, and 20, respectively, that is, the amount of distilled water added was 10mL, 20mL, 30mL, and 40mL, respectively. The centrifuge tube was placed in an ultrasonic cleaner for 30 minutes, the ultrasonic frequency was 40KHz, the ultrasonic temperature was 25°C, and then centrifuged for 10 minutes, the centrifugal speed was 8000r / min, and the ultrasonic and centrifugal steps were repeated once, and the supernatant was extracted to obtain the Daqu extract for detecting the pH value, and then the Daqu extract was detected by a pH meter to obtain the pH value. At each different ratio, 10 pieces of Daqu were taken from the white, yellow, and black Daqu samples for detection, and the average and standard deviation were calculated. The range of different types of Daqu was determined by the average ± standard deviation, and the test results are shown in Table 6.

[0087] Table 6 pH range of different types of Daqu at different ratios

[0088]

[0089]

[0090] As can be seen from Table 6, only when the ratio of distilled water volume to Daqu sample mass is 10, the difference between the maximum value of the black qu interval and the minimum value of the yellow qu interval is the smallest, and the overlapping part of the interval range can be ignored. The pH value measured under this ratio can be used to distinguish between black qu and yellow qu. When the ratio is 5, 15, and 20, the overlapping part of the black qu interval and the yellow qu interval is too much, and it is impossible to distinguish them by pH value. It can be seen that adjusting the ratio of distilled water volume to Daqu sample mass can help to distinguish different types of Daqu by pH value.

[0091] Example 2 Investigating the effect of ultrasound time on the identification results of Daqu

[0092] The present embodiment is to explore the influence of different ultrasonic times on the identification results of Daqu, and the ultrasonic time includes 10min, 30min, 50min, and 70min. The ratio of the volume of distilled water to the mass of the Daqu sample is 10, and the remaining steps are the same as in Example 1. Under each different ultrasonic time, 10 pieces of Daqu are taken from the white, yellow, and black Daqu samples for detection, and their mean and standard deviation are calculated. The interval range of different types of Daqu is determined by the mean ± standard deviation, and the test results are shown in Table 7.

[0093] Table 7 pH range of different types of Daqu under different ultrasonic times

[0094]

[0095] As can be seen from Table 7, when the ultrasonic time is 10 minutes, the interval range of black koji and yellow koji overlap a lot, and the pH value cannot be used to distinguish and identify black koji and yellow koji. When the ultrasonic time is 30 minutes, 50 minutes, and 70 minutes, the interval ranges of black koji, yellow koji, and white koji do not overlap or the overlapping parts are negligible, but in order to save identification time and energy consumption, the ultrasonic time is selected as 30 minutes in this application. It can be seen that adjusting the ultrasonic time can help to distinguish different types of Daqu using pH value.

[0096] Example 3 Investigating the effect of centrifugal speed on Daqu identification results

[0097] The present embodiment is to explore the influence of different centrifugal speeds on the identification results of Daqu, and the centrifugal speed includes 5000r / min, 6000r / min, 7000r / min, and 8000r / min. The ratio of the volume of distilled water to the mass of the Daqu sample is 10, the ultrasonic time is 30min, and the remaining steps are the same as in Example 1. Under each different centrifugal speed, 10 Daqu samples of Baiqu, Huangqu, and Heiqu Daqu are respectively taken for detection, and their mean value and standard deviation are calculated. The interval range of different types of Daqu is determined by mean value ± standard deviation, and the test results are shown in Table 8.

[0098] Table 8 pH range of different types of Daqu at different centrifugal speeds

[0099]

[0100] As can be seen from Table 8, only when the centrifugal speed is 8000r / min, the difference between the maximum value of the black qu interval and the minimum value of the yellow qu interval is the smallest, and the overlapping part of the interval range can be ignored. The pH value measured under this ratio can be used to distinguish between black qu and yellow qu. When the centrifugal speed is 5000r / min, 6000r / min, and 7000r / min, the overlapping part of the black qu interval and the yellow qu interval is too much, and it is impossible to distinguish them by pH value. It can be seen that adjusting the centrifugal speed can help to distinguish different types of Daqu by pH value.

[0101] Example 4 Investigating the effects of different centrifugation times on the identification results of Daqu

[0102] This embodiment is to explore the influence of different centrifugation times on the identification results of Daqu, and the centrifugation time includes 5min, 10min, 15min, and 20 / min. The ratio of the volume of distilled water to the mass of the Daqu sample is 10, the ultrasonic time is 30min, the centrifugal speed is 8000r / min, and the remaining steps are the same as in Example 1. Under each different centrifugation time, 10 pieces of Daqu are taken from the white, yellow, and black Daqu samples for detection, and their mean value and standard deviation are calculated. The interval range of different types of Daqu is determined by the mean value ± standard deviation, and the test results are shown in Table 9.

[0103] Table 9 pH range of different types of Daqu at different centrifugation times

[0104]

[0105] As can be seen from Table 9, when the centrifugation time is 5min and 20min, the interval range of black koji overlaps with the interval range of yellow koji, and the pH value cannot be used to distinguish and identify black koji and yellow koji. When the ultrasonic time is 10min and 15min, the interval ranges of black koji, yellow koji, and white koji do not overlap or the overlapping parts are negligible, but in order to save identification time and energy consumption, the centrifugation time is selected as 10min in this application. It can be seen that adjusting the centrifugation time can help to distinguish different types of Daqu using pH value.

[0106] This application uses pH value to identify the type of Daqu by adjusting the ratio of distilled water volume to Daqu mass, supernatant time, centrifugal speed and centrifugal time in Daqu pH detection. By using two identification indicators (pH value and melanoidin concentration) as indicators for identifying Daqu, the accuracy of identifying the type of Daqu can be greatly improved; at the same time, the identification indicators of this application are pH value and melanoidin concentration, the detection method is simple and fast, and the time for identifying Daqu can be greatly reduced. In addition, the detection instrument is simple, which greatly reduces the cost of using the instrument, and is suitable for identifying large quantities of Daqu on the production line.

[0107] 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 identifying different types of demolition songs, characterized in that: The following steps are involved: (1) taking a Daqu sample, and adding a solvent to the Daqu sample to obtain a Daqu extract; (2) detecting the pH value and melanoidin concentration of the Daqu extract; (3) identifying the type of the Daqu sample according to the pH value and melanoidin concentration of the Daqu extract; In the step (1), adding a solvent to the Daqu sample to obtain a Daqu extract comprises: when detecting the pH value of the Daqu extract, adding distilled water to the Daqu sample, first ultrasonicating for 25 to 35 minutes, then centrifuging for 8 to 12 minutes, the centrifugal speed is 7500 to 8500 r / min, repeating the ultrasonicating and centrifuging steps once, extracting the supernatant, and obtaining the Daqu extract; the ratio of the mass of the Daqu sample to the volume of the distilled water is 1:(9 to 11); When the type of Daqu determined by the pH value of the Daqu extract is inconsistent with the type of Daqu determined by the melanoidin concentration of the Daqu extract, The pH value of the Daqu extract is subtracted from the average pH value of the Daqu type determined by the pH value to obtain a difference, and the absolute value of the difference is divided by the pH standard deviation to obtain a pH standard deviation ratio; The melanin concentration of the Daqu extract is subtracted from the average melanin concentration of the Daqu type determined by the melanin concentration to obtain a difference, and the absolute value of the difference is divided by the melanin concentration standard deviation to obtain a melanin concentration standard deviation ratio; If the pH value standard deviation ratio is less than the melanoidin concentration standard deviation ratio, identifying the type of the Daqu sample according to the pH value; If the pH value standard deviation ratio is greater than or equal to the melanoidin concentration standard deviation ratio, the type of the Daqu sample is identified based on the melanoidin concentration.

2. The method according to claim 1, characterized in that In the step (3), identifying the type of the Daqu sample according to the pH value and melanoidin concentration of the Daqu extract comprises: When the pH value of the Daqu extract is within the interval to which the pH value of Baiqu belongs, and / or the melanoidin concentration of the Daqu extract is within the interval to which the melanoidin concentration of Baiqu belongs, the Daqu sample is determined to be Baiqu; When the pH value of the Daqu extract is within the interval of the pH value of Huangqu, and / or the melanoidin concentration of the Daqu extract is within the interval of the melanoidin concentration of Huangqu, the Daqu sample is determined to be Huangqu; When the pH value of the Daqu extract is within the interval to which the pH value of Heiqu belongs, and / or the melanoidin concentration of the Daqu extract is within the interval to which the melanoidin concentration of Heiqu belongs, the Daqu sample is determined to be Heiqu.

3. The method according to claim 2, characterized in that The intervals to which the pH value of the white koji belongs, the intervals to which the melanin concentration of the white koji belongs, the intervals to which the pH value of the yellow koji belongs, the intervals to which the melanin concentration of the yellow koji belongs, the intervals to which the pH value of the black koji belongs, and the intervals to which the melanin concentration of the black koji belongs are defined as follows: Take white, yellow and black koji as Daqu determination samples respectively, wherein the Daqu determination samples are determined by sensory evaluation; Calculating the average pH value and standard deviation of the Daqu determination samples of the white, yellow and black koji, as well as the average melanoidin concentration and standard deviation, respectively, wherein the pH value and the melanoidin concentration are obtained by the steps (1) and (2); The pH value intervals and the melanoidin concentration intervals of the white koji, yellow koji and black koji are determined according to the average value and the standard deviation.

4. The method according to claim 3, characterized in that: The pH value of the white koji belongs to an interval greater than or equal to 6.75, and the melanin concentration of the white koji belongs to an interval less than or equal to 1.65 mmol / L; The pH value of the yellow koji is in the range of 5.95 to 6.75, and the concentration of the yellow koji melanoidin is in the range of 1.65 to 2.40 mmol / L; The pH value of the black koji belongs to a range less than or equal to 5.95, and the melanin concentration of the black koji belongs to a range greater than or equal to 2.40 mmol / L.

5. The method according to claim 1, characterized in that The mass of the Daqu sample is 1 to 3 g.

6. The method according to claim 5, characterized in that The mass of the Daqu sample taken is 2g.

7. The method according to claim 1 or 2, characterized in that: In the step (1), when the pH value of the Daqu extract is detected, adding a solvent to the Daqu sample to obtain the Daqu extract comprises: adding distilled water to the Daqu sample, first ultrasonicating for 30 minutes, then centrifuging for 10 minutes at a centrifugal speed of 8000 r / min, repeating the ultrasonicating and centrifuging steps once, extracting the supernatant, and obtaining the Daqu extract.

8. The method according to claim 7, characterized in that The ratio of the mass of the Daqu sample to the volume of the distilled water is 1:

10.

9. The method according to claim 1 or 2, characterized in that: In the step (1), when the melanin concentration of the Daqu extract is detected, a solvent is added to the Daqu sample to obtain the Daqu extract, which comprises: adding a 40% ethanol solution to the Daqu sample, soaking it at 70°C for 2.5 to 3.5 hours, and then centrifuging it for 8 to 12 minutes at a centrifugal speed of 7500 to 8500 r / min, repeating the soaking and centrifugation steps once, and extracting the supernatant to obtain the Daqu extract.

10. The method according to claim 1, characterized in that In the step (1), when the melanin concentration of the Daqu extract is detected, a solvent is added to the Daqu sample for extraction to obtain the Daqu extract, comprising: adding a 40% ethanol solution to the Daqu sample, soaking at 70°C for 3 hours, and then centrifuging for 10 minutes at a centrifugal speed of 8000 r / min, repeating the soaking and centrifugation steps once, extracting the supernatant, and obtaining the Daqu extract.

11. The method according to claim 9, characterized in that The ratio of the mass of the Daqu sample to the volume of the ethanol solution is 1:(16.5-18.5).

12. The method according to claim 9, characterized in that The ratio of the mass of the Daqu sample to the volume of the ethanol solution is 1:17.

5.

13. The method according to claim 9, characterized in that In the step (2), detecting the melanoidin concentration of the Daqu extract comprises: detecting the absorbance of the Daqu extract at a wavelength of 470 nm, and then calculating the melanoidin concentration according to the Lambert-Beer law formula.

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