Measurement apparatus and measurement method for koji production process

Abstract

To provide a measurement apparatus and a measurement method that quickly measure a growth condition of koji mold during a koji production process and determine a growth status of the koji mold, the measurement apparatus according to the present invention that measures the koji production process includes: a nuclear magnetic resonance device that measures a nuclear magnetic resonance signal emitted from a hydrogen nucleus in a moisture content contained in a sample, the nuclear magnetic resonance device having a function to measure a T2 relaxation time constant of 1H from the measured nuclear magnetic resonance signal; a storage device that stores the T2 relaxation time constant of 1H measured by the nuclear magnetic resonance device over time; and a determination device that determines the T2 relaxation time constant or a change value of the T2 relaxation time constant stored in the storage device.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for measuring the koji-making process using a nuclear magnetic resonance spectrometer. [Background technology]

[0002] Koji is made by growing Aspergillus oryzae, a type of mold, on grains such as rice, wheat, and soybeans, and is essential for the production of fermented foods such as sake (Japanese sake), shochu, soy sauce, and miso. In the case of sake, the Aspergillus oryzae contained in the koji converts rice starch into sugar, making it essential for sake brewing. Aspergillus oryzae also converts rice protein into amino acids, which gives sake its rich flavor and umami taste. The process of koji making involves inoculating steamed ingredients with koji mold, allowing it to attach to the surface of the ingredients, and then controlling the temperature and humidity to allow the koji mold to grow. Koji for sake is made by inoculating steamed rice with koji mold and cultivating it in a koji room. The koji room is kept at about 33°C, providing an environment that is conducive to the growth of koji mold. The koji germinates after inoculation and grows mycelium inside the steamed rice while breaking down the steamed rice. During the decomposition process, enzymes (such as α-amylase and protease) necessary for sake production are produced. After about 50 hours have passed since the koji mold germinated and invaded the steamed rice, the koji necessary for sake production is complete. During this time, the toji and brewers control the temperature of the steamed rice and the evaporation of water from the steamed rice, adjust the moisture content of the steamed rice, and promote the supply of oxygen so that the koji mold produces the desired enzymes and grows inside the steamed rice (hasekomi). If the koji mold grows too much, the koji turns yellow-green and a cyst appears from the mycelium. This is the source of the bitterness and astringency. If the koji mold is allowed to grow too much, it will cause an unpleasant taste in the sake, which is undesirable for sake brewing. It is necessary to stop the growth of the koji mold (fermentation, degree of breakage) at the right time. These tasks are carried out by the toji and brewers, who look at the steamed rice and koji, taste them, touch them with their hands, and smell them, relying on their experience and intuition.

[0003] Regarding the measurement of fungi using a nuclear magnetic resonance apparatus, Patent Documents 1 to 3 describe techniques for measuring mycelia growing in a mushroom culture medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-27042 A [Patent Document 2] Patent Publication No. 2021-189108 [Patent Document 3] JP 2023-58327 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a measuring device and a measuring method for quickly measuring the growth state of koji mold in the koji-making process and judging the growth status of the koji mold. [Means for solving the problem]

[0006] The present invention is characterized by having the following configuration and is intended to solve the above problems. [1] A measuring device for measuring the koji-making process, A nuclear magnetic resonance device that measures a nuclear magnetic resonance signal emitted from hydrogen nuclei in water contained in a sample; The nuclear magnetic resonance apparatus measures the nuclear magnetic resonance signal. 1 It has the function of measuring the T2 relaxation time constant of H, Measured by the nuclear magnetic resonance spectrometer 1 a storage device that stores the T2 relaxation time constant of H over time; A determination device for determining the T2 relaxation time constant or a change in the T2 relaxation time constant stored in the storage device; A measuring device comprising: [2] The measuring device according to [1], wherein the storage device stores the T2 relaxation time constants of multiple samples having the same aging time as an average value. [3] The measuring device according to [1] or [2], further comprising a determination device for determining a change in the T2 relaxation time constant stored in the storage device and generating a signal. [4] The measurement device according to [4], further comprising a judgment device that measures the difference in the change value of the T2 relaxation time constant stored in the memory device, judges the difference, and generates a signal. [5] The measuring device according to [1] or [2], further comprising: a measuring device for calculating an enzyme activity or a bacterial cell amount in a sample from the T2 relaxation time constant stored in the storage device. [6] A method for measuring the koji-making process, comprising the steps of: The nuclear magnetic resonance spectrometer detects the nuclear magnetic resonance signals emitted from the hydrogen nuclei in the water contained in the sample. 1 Measuring the T2 relaxation time constant of H; The measured value in the measurement step 1 storing the T2 relaxation time constant of H over time; A step of determining the T2 relaxation time constant or a change in the T2 relaxation time constant stored in the storage step; Measurement methods including. Effect of the Invention

[0007] By measuring the T2 relaxation time constant of koji during the koji-making process, it is possible to quantitatively quantify the growth of the koji mold (hassei). In addition, because the T2 relaxation time constant can be measured in a short time (about 1 second), it is possible to instantly provide numerical information on the state of the koji during fermentation. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a time chart of the koji-making process and the time when samples were collected. [Diagram 2] FIG. 1 is a schematic diagram of a measuring device of the present invention. [Diagram 3] FIG. 1 is a schematic diagram of a CPMG sequence for acquiring echo signals for calculating signal intensity and a T2 relaxation time constant. [Figure 4] FIG. 2 is a graph showing changes in moisture content of koji rice during the koji-making process. [Diagram 5] FIG. 1 shows changes in the T2 relaxation time constant of koji rice during the koji-making process. [Figure 6] FIG. 13 is a graph showing the difference in T2 relaxation time constant between koji rice and steamed rice controls over time. [Figure 7] This shows the enzyme activity (left) and bacterial mass (right) of koji rice over time. [Figure 8] This is a correlation diagram between the difference in T2 between koji rice and steamed rice and enzyme activity (left: α-amylase, right: glucoamylase). [Figure 9] This is a correlation diagram between the difference in T2 between koji rice and steamed rice and the amount of fungal cells. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The process of koji making consists of the steps of steaming rice, wheat, soybeans and other ingredients to produce the steamed ingredients, sprinkling koji seed on the steamed ingredients, mixing the ingredients with the koji seed evenly, propagating koji mold on the ingredients in a hot and humid environment, reducing the activity of the koji mold, and removing the koji from the koji room and allowing it to cool and dry. Among these, the steps from propagating koji mold to reducing its activity usually take 2-3 days and are done by hand, controlling the temperature and humidity, feeling the condition of the koji with the five senses, and relying on experience and intuition. As an example of the koji making process for sake, as shown in Figure 1, the steps are steaming → pulling in → seeding → cutting → mori → naka-shigoto → shimai-shigoto → karashi → dekoji.

[0010] To explain the process of koji making for sake, starting from the process of sprinkling seed koji on the steamed ingredients, using an example, the process of propagating koji mold involves piling up the steamed rice sprinkled with seed koji and wrapping it in a blanket or other cloth to keep it warm and moist, allowing the koji mold spores to germinate and grow for several hours, followed by a process called kirikaeshi. After several hours, the steamed rice (koji rice) with koji mold attached to it will have stuck together and become hard, so the pile of steamed rice is broken up once, the koji rice is loosened and mixed to make the temperature uniform and supply oxygen to the koji mold, and then the koji rice is gathered again into a pile and wrapped in a blanket or other cloth to keep it warm and moist. After 11 to 12 hours or more have passed since the kirikaeshi process, white spots begin to appear on the surface of the koji rice. Usually, the next process, called mori, is carried out 10 hours or so after kirikaeshi. For mori, the koji rice wrapped in a pile is separated into individual grains and piled to a certain thickness on a koji lid, koji box, or tent to keep it warm and moist. The next step after mori is called nakashigoto. nakashigoto is carried out about 6 to 8 hours after mori, and involves mixing the koji rice and spreading it out more evenly and thinly than when it was in the mound, lowering the temperature of the koji rice and making it more uniform, supplying oxygen to the koji rice. After nakashigoto, the temperature of the koji rice rises, and the koji mold grows. After about 6 to 7 hours have passed since nakashigoto, when the temperature of the koji rice has reached about 40°C, the next step, shimai-shigoto, is carried out. In shimai-shigoto, the hardened koji rice is loosened and mixed, and the layers are spread out to increase the surface area. 8 to 12 hours after shimai-shigoto, a process called karashi is carried out, which involves loosening and mixing the hardened koji rice to increase the surface area of ​​the koji rice, lowering its temperature, and drying it to slow the growth of the koji mold. After karashi, the koji rice cools to around 30°C, and after a few hours it is removed from the koji room and left to cool and dry in a cooler place, and the koji rice is complete.

[0011] In the process of making koji for sake mentioned above, particularly when producing the koji mold for sake called daiginjo, the process from multiplying the koji mold to reducing its activity is an important step in producing high-quality daiginjo sake with few unpleasant flavors. In particular, the timing of the final stage of withering is crucial, and the toji and brewers look at, taste, touch and smell the koji rice, relying on their experience and intuition.

[0012] The measuring device for measuring the koji-making process of the present invention comprises a nuclear magnetic resonance device, a storage device, and a judgment device. The nuclear magnetic resonance apparatus of the present invention measures the nuclear magnetic resonance signals emitted from the excited hydrogen nuclei of water by applying a magnetic field to the hydrogen nuclei, and extracts the nuclear magnetic resonance signals. 1 The storage device has a function of measuring the T2 relaxation time constant of H. 1 The storage device stores the T2 relaxation time constant of H over time. The determination device determines the T2 relaxation time constant or a change in the T2 relaxation time constant stored in the storage device.

[0013] The nuclear magnetic resonance apparatus measures nuclear magnetic resonance signals emitted from excited atomic nuclei of hydrogen atoms in water by applying a magnetic field to the hydrogen nuclei, and calculates a magnetic field from the nuclear magnetic resonance signals. 1 The device may have a function of measuring the T1 relaxation time constant of H. The T1 relaxation time constant shows a high correlation with the water content of a sample, and by utilizing this, the water content of the sample can be measured in a short period of time.

[0014] The storage device can store, as an average value, the T2 relaxation time constants of a plurality of samples that have been subjected to the same aging time in the koji-making process using the nuclear magnetic resonance device.

[0015] The judgment device includes a device for judging the change in the T2 relaxation time constant stored in the storage device and issuing a signal, and preferably includes a judgment device for measuring the difference in the change and issuing a signal. The signal is preferably issued at the point in time when there is almost no difference in the change in the T2 relaxation time constant over time, or when the change reaches a maximum value. The point in time when there is almost no difference in the change in the T2 relaxation time constant over time, or when the change reaches a maximum value, corresponds to the start of a process called "withering" which is just before the final process of the koji-making process described below.

[0016] In addition, by monitoring the rate of increase in the T2 relaxation time constant (the increase in the T2 relaxation time constant per unit time), it is possible to determine whether the progress of the fermentation of the rice koji (bacterial activity) is appropriate. If the rate of increase is slow, the fermentation is progressing slowly, and conversely, if the rate of increase is fast, the fermentation is progressing rapidly.

[0017] In addition to the sample in the koji-making process (koji sample), the judgment device can also measure the T2 relaxation time constant of a control sample, which is a sample made by placing a steamed raw material without sprinkling koji mold under the same conditions as the koji-making process, and judge the T2 relaxation time constant or the change in the T2 relaxation time constant from the difference between the T2 relaxation time constants of the koji sample and the control sample. The difference can be used to grasp the state of change more clearly than the T2 relaxation time constant.

[0018] Alternatively, the change in the T2 relaxation time constant may be calculated by dividing the difference in the T2 relaxation time constant between two points measured over time by the elapsed time.

[0019] The present invention may also be a measuring device that measures the enzyme activity or the amount of bacteria in a sample from the T2 relaxation time constant stored in the storage device. There is a correlation between the enzyme activity or bacterial mass of a koji sample and the difference in the T2 relaxation time constants of the koji sample and the control sample, and the bacterial mass in the koji sample can be measured by measuring the difference in the T2 relaxation time constants. That is, the determination device stores a relational expression between the difference in the T2 relaxation time constants of the koji sample and the control sample and the enzyme activity or bacterial mass of the koji sample, and the difference is measured to determine the enzyme activity or bacterial mass.

[0020] The method for measuring the koji-making process of the present invention uses a nuclear magnetic resonance device to measure the nuclear magnetic resonance signals emitted from hydrogen nuclei in the water contained in the steamed rice on which the koji mold grows. 1 A step of measuring the T2 relaxation time constant of H, 1The measurement method includes the steps of: storing the T2 relaxation time constant of H over time; and determining the T2 relaxation time constant stored in the storing step or a change in the T2 relaxation time constant.

[0021] The measurement device and method of the present invention will be described below with reference to FIG. As shown in FIG. 2, the measurement device of the present invention includes an NMR / MRI measurement unit 1, a calculation unit / storage unit / determination unit 2, and a magnetic field application unit 3. As shown in FIG. 2, an NMR signal emitted from a sample 526 is received by an RF coil 524 and accepted by a data accepting unit 540, after which a calculation unit 542 calculates the signal intensity.

[0022] The magnetic field application unit 3 has a static magnetic field application device 520 that applies a static magnetic field to the entire sample 526, a gradient magnetic field application device 522 that applies a gradient magnetic field to the entire sample 526, and an RF coil 524 that applies an excitation oscillating magnetic field to the entire sample 526 and receives a nuclear magnetic resonance signal. The RF coil 524 is a device for applying an excitation oscillating magnetic field to the sample 526 and receiving a nuclear magnetic resonance signal emitted from the sample 526. The RF coil 524 is connected to a resonance circuit 521 to resonate the RF coil 524 near the nuclear magnetic resonance frequency. The gradient magnetic field application device 522 is used when imaging the NMR signal. By applying an excitation oscillating magnetic field to a sample, the signal intensity and the T1 and T2 relaxation time constants can be obtained from the NMR signal emitted from the sample.

[0023] As shown in FIG. 2 , the NMR / MRI measurement unit 1 includes a shaper 502 that shapes the waveform of an excitation electromagnetic wave, an excitation electromagnetic wave oscillator 504 that generates an excitation electromagnetic wave, a modulator 506 that modulates the excitation electromagnetic wave with the waveform output from the shaper, an amplifier 508 that amplifies the excitation electromagnetic wave, a switch (SW) 510 that electrically switches between the excitation electromagnetic wave and the waveform of a received nuclear magnetic resonance signal, a low noise amplifier (LNA) 512 that amplifies the nuclear magnetic resonance signal, an analog / digital (A / D) converter / detector 516 that converts the nuclear magnetic resonance signal into a digital signal and detects it with the excitation electromagnetic wave, a control unit 530 that controls the shaper, A / D converter / detector, current control unit, etc., for the signal output from the A / D converter / detector, a measurement unit 532, a sequence table 534, a data receiving unit 540, and a current control unit 528 that supplies current to the gradient magnetic field application device.

[0024] The calculation unit / storage unit / judgment unit 2 has a calculation unit 542 that calculates signal intensity from a nuclear magnetic resonance signal to determine the T2 relaxation time constant, a memory unit 546 that stores the T2 relaxation time constant determined by the calculation unit 542, a judgment unit 548 that judges the change in the T2 relaxation time constant stored in the memory unit 546, and an output unit 550.

[0025] 3 or parameters required to construct the sequence from the sequence table 534 via the control unit 530, and sends control commands required for measurement to the control unit 530. The control unit 530 sends control commands according to the sequence to devices including the shaper 502, oscillator 504, A / D converter / detector 516, current control unit 528, and data receiving unit 540. The control unit 530 sends a waveform for shaping the excitation electromagnetic wave corresponding to the sequence to the shaper 502.

[0026] The oscillator 504 receives frequency information corresponding to the measurement from the control unit 530, and oscillates a basic waveform that becomes an excitation electromagnetic wave. The waveform shaped by the shaper 502 and the basic waveform output from the oscillator 504 are received by a modulator 506, which modulates the basic waveform to form an excitation electromagnetic wave. This excitation electromagnetic wave is amplified by an amplifier 508, and is sent to an RF coil 524 via a switch (SW) 510. As a result, the RF coil 524 excites a sample 526.

[0027] A nuclear magnetic resonance signal emitted from the sample 526 and received by the RF coil 524 is sent to a low noise amplifier (LNA) 512 via a switch (SW) 510. The low noise amplifier amplifies the nuclear magnetic resonance signal, and the amplified signal is converted into a digital signal by an A / D converter / detector 516. The nuclear magnetic resonance signal is detected using a reference waveform received from an oscillator 504, and the frequency of the signal is lowered. The signal output from the A / D converter / detector 516 is acquired by a data receiving unit 540.

[0028] The calculation unit 542 is a device that calculates the signal intensity corresponding to the sequence as necessary based on the signal obtained by the data receiving unit 540. In the present invention, the T2 relaxation time constant is calculated based on the signal obtained by the data receiving unit 540.

[0029] The method of measuring the T2 relaxation time constant is described below. As an example, the case of using the sequence shown in FIG. 3 is shown. Using multiple sequences with different echo times TE, nuclear magnetization is excited and multiple NMR signals are acquired. The T2 relaxation time constant is obtained by approximating with an exponential function that relates multiple echo times TE to multiple signal intensities. When the first excitation pulse is a 90-degree pulse and the second excitation pulse is a 180-degree excitation pulse in FIG. 3, the obtained T2 relaxation time constant is the T2 relaxation time constant by the Hahn echo method. Other representative methods for measuring the T2 relaxation time constant include the Carr-Purcell-Meiboom-Gill (CPMG) method (Patent Document 3).

[0030] The T2 relaxation time constants calculated by the calculation unit 542 are stored in the memory unit 546. The memory unit 546 stores all the measured T2 relaxation time constants in association with the time the sample was collected and the culture time (the time elapsed from the step of sprinkling the seed koji). The memory unit 546 can store the T2 relaxation time constants of multiple samples with the same aging time as an average value. By measuring multiple samples collected at different locations at the same time, data can be obtained in which the variations due to differences in collection locations have been averaged.

[0031] Judgment unit 548 judges the start time of each step of the koji-making process from the change over time of the T2 relaxation time constant stored in memory unit 546, and sends a signal to output unit 550. The change in the T2 relaxation time constant can be judged by measuring the difference in the change over time. It can also be judged from the maximum value of the change in the T2 relaxation time constant. In particular, judgment based on the difference in the change is effective in judging the time for intermediate work and withering, and judgment based on the maximum value of the change is effective in judging the time for withering.

[0032] The output unit 550 receives the signal generated by the determination unit 548 and outputs the signal to the outside of the device. The output signal may be, for example, an electrical, sound, or light signal, and is preferably an electrical signal. With an electrical signal, if one carries a receiver, the signal can be received regardless of one's location. EXAMPLES

[0033] The following is an example of the production of rice koji for Daiginjo sake and NMR measurement.

[0034] (NMR measurement equipment) A permanent magnet (magnetic field strength 1.1 Tesla, air gap 110 mm, manufactured by NEOMAX Engineering) was used as a magnetic field application device to the sample. The NMR console used for excitation and reception of NMR signals is composed of the following equipment: DDS (DST), ADC (DATEL ADC414), DSP+DSP daughter, PC (WinXP), detector DTRX3Plus (DST), PA (DST), gradient magnetic field power supply (Jonan Electronics), LNA (DST), DANT-SW (DST). The measurement software used was Sampler6 (MR Technology). The RF probe used an LC tank circuit with a homemade solenoid coil with an inner diameter of 30 mm.

[0035] (Measurement sample) Approximately 0.4 to 0.5 g of sample (approximately 15 grains of rice) was placed in an NMR sample tube with an outer diameter of 10 mm and a length of 150 mm (Shigemi, S-10-003) and measurements were performed. An acrylic rod with an outer diameter of 8 mm was inserted into the sample tube to hold the sample in place and prevent it from moving (the acrylic rod was left inserted during NMR measurements). The length of the sample was approximately 15 mm.

[0036] (Method of measuring T2 relaxation time constant) With the static magnetic field direction in the Z-axis direction, a 180-degree excitation pulse (excitation direction is in the Y-axis direction) is applied after tau time has elapsed from the 90-degree excitation pulse (excitation direction is in the X-axis direction), and then after n×tau time (n is an even number such as 2, 4, 6, 8, etc.), excitation is performed with a 180-degree excitation pulse (excitation direction is in the Y-axis direction). By orthogonalizing the excitation direction, imperfections in the excitation are compensated for. This method is called the CPMG method. In this measurement, tau was set to 0.5 ms. Echo signals are generated at 1 ms intervals. Signals were acquired up to about 40 ms. The number of integrations was set to 2. The repetition time TR of the 90-degree excitation pulse was set to 10 seconds. The measurement time was about 20 seconds. However, the T1 relaxation time constant of koji is about 100 ms, and if the number of integrations is set to one, the CPMG measurement can be completed in 1 second. Even-numbered echo signals were acquired. The signal intensity decreased exponentially, and the logarithm of the signal intensity decreased almost linearly. The relationship between the time elapsed from the 90-degree excitation pulse and the signal intensity (taken as the natural logarithm) was approximated by a straight line, and the T2CPMG value was calculated from the slope. Here, the T2CPMG value is equivalent to the T2 relaxation time constant.

[0037] (NMR and moisture content measurements of koji rice) The koji-making process of koji rice (for daiginjo, Yamada Nishiki, 35% polished rice) was measured with an NMR measurement device. The koji rice was sampled 10 times from the drawing in to the dekoji at the times indicated by circled numbers (process numbers) 1 to 10 in Figure 1. In Figure 1, the circled numbers (process numbers) indicate the time elapsed from the time of sample collection and the time when the warming after seeding began as the reference. The samples were collected from almost the center of the thickness direction of the koji rice, where the koji rice was not directly exposed to air. Five samples were collected from different points to reduce location-dependent variation. In addition, a block of steamed rice weighing about 3 kg, without seed koji, was covered with cloth and kept at the same temperature as the koji rice as a control sample. This was collected at the same time as the koji rice and subjected to NMR measurement in the same way.

[0038] To measure the moisture content, the sample was removed from the sample tube after NMR measurement and placed on a small dish (approximately 30 mm in diameter) made from an aluminum wheel. The mass of the sample, m_wet [g], was measured using an electronic balance. The sample was then dried in a dryer (102°C) for 1-2 days and the dry mass, m_dry [g], was measured. The moisture content γ [%] was defined by the following formula based on the dry mass of the koji. γ=(m_wet−m_dry)×100 / m_dry[%] Here, (m_wet-m_dry) shown in the numerator of the above equation is the mass of water contained in the sample.

[0039] The moisture content of the koji rice during the koji-making process is shown in Figure 4. The left graph in Figure 4 shows the results of measuring five samples taken at each collection time point, and the right graph plots the average value. The moisture content of the control decreased monotonically with time. The control was wrapped in cloth, but because the koji room (temperature 33°C, relative humidity approximately 35%) was dry, moisture evaporated from the surface of the control, and the moisture content of the control gradually decreased. On the other hand, the moisture content of the koji sample remained almost constant until near the shimai-shigoto stage. This is thought to be because the rice starch was broken down by the respiration of the koji mold, generating water, which compensated for the drying of the koji. After shimai-shigoto, the moisture content of the koji sample decreased significantly. This is thought to be because the water production due to respiration in the koji sample became more active, the koji temperature rose to 43-45°C, and the release of water vapor from the koji sample increased.

[0040] The results of measuring the T2 relaxation time constant during the koji rice koji-making process are summarized in Figure 5. The left panel in Figure 5 shows the results of measuring five samples taken at each sampling time point, and the right panel plots the average values.

[0041] The T2 relaxation time constant of the control decreased monotonically with time. As shown in the additional figure, the moisture content of the control decreased. The T2 relaxation time constant depends on the amount of free water in the sample, and as the amount of free water decreases, the T2 relaxation time constant decreases. Furthermore, steamed rice hardens over time. It is thought that the T2 relaxation time constant of the control decreased with the decrease in moisture content in response to these two effects.

[0042] The T2 relaxation time constant of the koji sample decreased over time from the time of drawing in to the time of nakajishi, but the rate of decrease became smaller as the nakajishi approached. Until the nakajishi, the T2 relaxation time constant decreased due to hardening of the koji sample, but the difference with the control is thought to be that the T2 relaxation time constant was longer than the control due to water (free water) generated by the respiration of the koji mold. The T2 relaxation time constant increased after nakajishi and continued to increase until the time of withering, but the rate of increase became smaller as the withering approached. After withering, the T2 relaxation time constant decreased. From around the nakajishi, water production gradually becomes more active due to the respiration of the koji mold, and the temperature of the koji also gradually rises, but it is thought that more water (free water) is produced than the amount of water evaporated, causing the T2 relaxation time constant to become longer. After shimai-shigoto, the temperature of the koji sample reaches its highest temperature (43-45°C), so the amount of water evaporated also increases, and the increase in the T2 relaxation time constant becomes gradual, and the T2 relaxation time constant is thought to peak around the time of withering. After drying, the cloth covering the koji sample is removed, and the amount of water evaporation increases dramatically, causing a rapid decrease in moisture content and a drop in the koji temperature to around 33°C. This is thought to have reduced the activity of the koji mold and shortened the T2 relaxation time constant.

[0043] Figure 6 shows the difference in the T2 relaxation time constant between the koji rice and steamed rice control shown in the right panel of Figure 5. The difference increased from the drawing in process to the withering process, and then decreased. The biggest difference between the control and the koji sample is whether or not it contains moisture (free water) generated by the koji. It is thought that the moisture (free water) in the koji sample increased over time, and that this resulted in a corresponding increase in the T2 relaxation time constant.

[0044] (Method for measuring enzyme activity and bacterial mass of koji rice) The enzyme activities of koji rice were measured for α-amylase and glucoamylase. α-amylase was measured using an α-amylase measurement kit (Kikkoman Biochemifa Corporation), and glucoamylase was measured using a saccharification power fractionation quantification kit (Kikkoman Biochemifa Corporation).

[0045] The amount of fungal cells was measured by the koji measurement method using Yatalase (J. Brew. Soc. Japan. Vol. 87, No. 10, 757-779 (1992)).

[0046] Figure 7 shows the enzyme activity (left) and bacterial mass (right) of koji rice versus time elapsed from the start of incubation after seeding. The samples used to measure enzyme activity and bacterial mass were collected at the same time as the samples collected during NMR measurement. The plots on the graph in the figure correspond to the sampling times of circled numbers 1 to 10 shown in Figure 1, which were collected during NMR measurement. As time passes, it increases in the same way as the difference in the T2 relaxation time constants between koji rice and the steamed rice control.

[0047] Figure 8 is a correlation diagram between the difference between T2 of koji rice and T2 of steamed rice and enzyme activity. The diagram on the left is α-amylase, and the diagram on the right is glucoamylase. It can be seen that there is a good correlation between the activity of both enzymes and the difference value.

[0048] 9 is a correlation diagram between the difference between T2 of koji rice and T2 of steamed rice and the amount of fungal cells. The amount of fungal cells also shows a good correlation with the difference value. [Industrial Applicability]

[0049] The measuring device and measuring method of the present invention can be used to judge the koji-making process.

Claims

1. A measuring device for measuring the koji-making process, A nuclear magnetic resonance device that measures a nuclear magnetic resonance signal emitted from hydrogen nuclei in water contained in a sample; The nuclear magnetic resonance apparatus measures the nuclear magnetic resonance signal. １ It has a function of measuring the T2 relaxation time constant of H, Measured by the nuclear magnetic resonance spectrometer １ a storage device that stores the T2 relaxation time constant of H over time; A determination device for determining the T2 relaxation time constant or a change in the T2 relaxation time constant stored in the storage device; A measuring device comprising:

2. 2. The measuring device according to claim 1, wherein the storage device stores the T2 relaxation time constants of a plurality of samples having the same aging time as an average value.

3. 3. The measurement device according to claim 1, further comprising a determination device that determines a change in the T2 relaxation time constant stored in the storage device and issues a signal.

4. 4. The measuring device according to claim 3, further comprising a determining device that measures a difference in the change values ​​of the T2 relaxation time constants stored in the storage device, determines the difference, and generates a signal.

5. 3. The measuring device according to claim 1, further comprising a memory device for storing a T2 relaxation time constant, the memory device being configured to store a T2 relaxation time constant and a T2 relaxation time constant stored in the memory device.

6. A method for measuring the process of koji making, comprising the steps of: The nuclear magnetic resonance spectrometer detects the nuclear magnetic resonance signals emitted from the hydrogen nuclei in the water contained in the sample. １ Measuring the T2 relaxation time constant of H; The measured value in the measurement step １ storing the T2 relaxation time constant of H over time; A step of determining the T2 relaxation time constant or a change in the T2 relaxation time constant stored in the storage step; Measurement methods including.

Images