JPH0441586B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method and apparatus for producing natto, and particularly to control of a fermentation process. (Prior art) Generally, natto is made by soaking raw soybeans in water for a predetermined time, then steaming them under a predetermined pressure, inoculating the soybeans with natto bacteria, and placing predetermined amounts of the soybeans into containers. It is produced by arranging it in containers and fermenting it in a fermentation room. Furthermore, in recent years, in the above-mentioned fermentation process, fermentation control has been automated by program control (for example, Japanese Patent Application Laid-Open No. 48-29144, Publication of Utility Model Publication No. 49-37999). In these fermentation controls, the room temperature (characteristic B) and humidity (characteristic C) in the fermentation chamber are controlled by a controller so that the temperature of soybeans in each container becomes characteristic A in FIG. 5, for example. In this control, the sixth
As shown in the figure, first, based on empirical values, pre-cooling, germination propagation, fermentation, ripening, and strong cooling are set in the controller for pre-cooling, germination, ripening, and strong cooling, and fermentation control is started using the start switch. . In fermentation control, based on the detection data of each room temperature sensor, humidity sensor, product temperature sensor, etc. installed in the room, the heating and cooling device installed in the fermentation room,
The humidifying/dehumidifying device and the air supply/exhaust device are driven. In other words, fermentation is promoted by heating, humidifying, and air supply/exhaust, and conversely, fermentation is suppressed by cooling and dehumidifying, so that control of growth of Bacillus natto and fermentation in the fermentation process achieves characteristic A. I am doing it. Data on this fermentation process is obtained by continuously recording room temperature, product temperature, and humidity using a recorder. The resulting natto products are then evaluated in terms of their appearance, taste, aroma, stringiness, stickiness, etc., and the sensory quality is compared. Furthermore, the program for the next day's fermentation process is modified based on the recorded data and the sensory quality comparison, and each setting is made using this modified program. (Problems to be Solved by the Invention) However, in the above-mentioned conventional technology, natto production was conducted based on the evaluation of manufactured natto products and sensory quality comparison, so natto was manufactured while checking the ripeness level. It was impossible to manufacture natto, and in order to make natto according to one's taste, one had no choice but to rely on experience. In addition, room temperature and humidity conditions may vary depending on the size of the fermentation room, the amount of soybeans prepared, the characteristics of the raw soybeans (size and quality, etc.), and the form and material of the container (preparation box), so these may change. and,
There was a problem that could not be resolved. Therefore, the present invention provides the following features in the soybean fermentation process:
By collecting and measuring the amount of ammonia gas generated from the soybeans in the container and controlling the room temperature and humidity based on this data, it is possible to directly control the progress of natto production, allowing you to create natto according to your taste. The purpose is to enable the production of (Means for Solving the Problems) The method for producing natto according to the first invention includes at least a humidifying/dehumidifying device of a heating/cooling device, in which soybeans inoculated with natto bacteria and put into a preparation box in fixed amounts are In a method for producing natto in which natto is produced by charging soybeans into a fermentation chamber and controlling the room temperature and humidity in the fermentation chamber, the amount of ammonia gas generated from the soybeans during the fermentation process is detected by a gas detection means, The apparatus for producing natto according to the second invention is configured to control the room temperature and humidity in the fermentation chamber by driving each of the apparatuses based on the detection data, and the natto production apparatus according to the second invention is inoculated with natto bacteria and In a natto production apparatus that ferments soybeans placed in batches in preparation boxes in a fermentation chamber to produce natto, the fermentation chamber includes a heating and cooling device that heats or cools indoor air, and a humidifier or dehumidifier for the indoor air. A humidifier and dehumidifier that
A gas detection means for detecting the amount of ammonia gas generated from the soybeans during the fermentation process, and controlling the room temperature and humidity in the fermentation chamber by driving each of the devices based on the detection data from the gas detection means. The configuration includes a control device. The reason why the temperature and humidity in the fermentation chamber were controlled based on the concentration of ammonia gas in the fermentation chamber was based on the following knowledge. That is, in the process of fermenting natto in a fermentation chamber, soybean protein is gradually degraded by proteolytic enzymes produced by the growth of the inoculated natto bacteria in the order shown by the arrows in Figure 3.
It is broken down into amino acids through water-soluble proteins. Furthermore, as the fermentation progresses, the amino acids are decomposed into unsaturated fatty acids, ammonia gas is generated, and the fermentation ends. It is known that since such reactions occur one after another in a power order during the fermentation process, the ratio of water-soluble nitrogen D, amino acid nitrogen E, and ammonia nitrogen F is as shown in FIG. 5, for example.
By detecting ammonia gas, it is possible to estimate the amount of water-soluble amino acids and free amino acids from the correlation, so it is possible to recognize the fermentation process and immediately link it to fermentation control. Therefore, by focusing on ammonia gas and detecting the ammonia gas concentration during the fermentation process, it becomes possible to control production while directly controlling quality in the fermentation process of natto. (Function) Therefore, until now, the amount of ammonia gas produced during the fermentation process is finally detected by the produced gas detection means and compared based on the previously known amount of produced gas. It is possible to know the progress of fermentation during the manufacturing process, which could not be accurately determined, and by controlling the room temperature and humidity in the fermentation chamber by driving each device installed in the fermentation chamber, it is possible to suppress or accelerate natto fermentation. You can control the progress of fermentation while checking it. (Example) An example of the present invention will be described below based on the drawings. FIG. 1 shows an outline of the fermentation chamber and control system of this example. In the figure, 21 is a fermentation chamber, and a ventilation circulation device 22 equipped with a device for circulating indoor air is attached to the upper part of this fermentation chamber 21. This ventilation circulation device 22 includes a fan (not shown) that sucks indoor air from four directions and blows it downward.
and a heating device 2 using a heater that heats the circulating air.
2a, a cooling device 25 that cools the circulating air, and a humidifying device 26a that humidifies the circulating air. An air supply device 23 that introduces outside air into the room and an exhaust device 24 that exhausts indoor air to the outside are installed in the upper part of the outdoor room.When necessary, the outside air is taken into the room through the air intake device 23, and oxygen is introduced. , used for auxiliary cooling indoors. Note that the intake device 23 and the exhaust device 24 constitute a supply and exhaust device. A dehumidifier 26b that dehumidifies the indoor air is provided on the other side of the room.
A humidifying/dehumidifying device is constituted by the humidifying device 26a and the humidifying device 26a. In addition to a room temperature sensor 30 and a humidity sensor 31, a temperature sensor 32 for detecting the temperature of soybeans in the containers 28 arranged in the container 27 is provided inside the room. This temperature sensor 32 is used to check the temperature of soybeans during the fermentation process and to control fermentation. Further, an introduction tube 33 is provided in the room with its tip facing into the room to introduce ammonia gas generated in the container 28 and mixed into the room. The proximal end of the introduction tube 33 is connected to a mass spectrometer 34 that analyzes the components and mass of the generated gas. The ventilation circulation device 22, heating device 22a, air intake device 23, exhaust device 24, cooling device 25, humidification device 26a, dehumidification device 26b, mass spectrometer (gas detection means) 34
and each sensor 30, 31, 32 is a control device 40
electrically connected to. As shown in FIG. 2, the control device 40 includes interfaces 4 that convert detection signals from the sensors 30, 31, and 32 into digital signals.
1, 42, 43 and each interface 41, 4
2, 43, and a measurement control section 44 that controls the detection data from the mass spectrometer 34 according to the measurement process; a microcomputer unit (MUC) 45;
Recorder 46 for recording humidity and product temperature data
and various devices such as ventilation circulation devices and cooling devices 2
2, 22a, 23, 24, 25, 26a, 26b
It consists of a drive section 47. The microcomputer unit 45 consists of an I/O port, memory, arithmetic section, control section clock generator, etc.
Based on the detection data of the mass spectrometer 34, the various control devices 22, 22a, 23, 24, 25, 2 are processed according to the program written in the memory.
6a and 26b are driven and controlled. In this embodiment, WSMR-1400 manufactured by Westron is used as the mass spectrometer 34.
This mass spectrometer 34 introduces indoor air through an introduction pipe 33 using the suction force of a differential pump, ionizes atoms and molecules of ammonia gas to be measured from the introduced air, and traces them in an electromagnetic field. The mass is measured using a 3D sensor, and the concentration value of the sampled ammonia gas component is output. Next, control in the fermentation process using the above-mentioned apparatus will be explained. When the control is started, the control shown in FIG. 4 is performed. That is, based on the gas amount data of ammonia gas detected by the mass spectrometer 34 and the product temperature data from the product temperature sensor 32, while indoor air is being circulated by driving the ventilation circulation device 22, the heating device 22a , cooling device 25, humidifying device 2
6a, the dehumidifying device 26b, the air intake device 23, and the exhaust device 24 are driven and controlled as appropriate to perform heating or cooling, humidification or dehumidification, and air intake or exhaust in the fermentation chamber 21 to maintain a room temperature suitable for the process in the fermentation process. The humidity and humidity are controlled, for example, as shown in FIG. In addition, the indoor humidity, product temperature, and room temperature will be
It is detected by each sensor 30, 31, 32 and the detection data is recorded in a recorder. At the same time, ammonia gas generated from soybeans during the fermentation process and mixed into the indoor air is introduced through an introduction pipe 33 to a mass spectrometer 34. The concentration is detected by the MCU (microcomputer) 4 based on this detection data.
Based on the data entered in advance in step 5, the amount of ammonia gas currently being generated from soybeans can be detected. It is known that the amount of ammonia gas generated changes over time, as shown in the attached table, for example. Therefore, it is possible to control the fermentation process by detecting the start and end points of each control period based on changes in the amount of gas generated. The amount of gas generated varies depending on the characteristics of the soybean, such as its size and quality.

[Table] Next, the quality coefficients of the raw soybeans are compared, and the control cycle is repeated while the program is modified based on this comparison.
In addition, since the above quality coefficient has a correlation with the amount of ammonia gas generated, for example, the release rate of amino acids and other generated substances, factors having these relationships can be used as a standard for product quality. By making comparisons during the control cycle, fine-grained control can be performed according to the characteristics of each soybean. First, during pre-cooling, by driving the cooling device 25, the soybeans in the container 28 drawn into the fermentation chamber 21 are quickly cooled to an appropriate temperature for the growth of Bacillus natto. When the soybeans are cooled in advance, they enter the induction period in which the inoculated Bacillus natto grows, as shown in Figure 4.
By heating, humidifying and inhaling air, the growth of natto bacteria is promoted, and each of the above-mentioned devices 22, 22
a, 23, 24, 26a, and 26b are driven to control the indoor temperature to approximately 40°C. Also, during this induction period, the indoor humidity is controlled to be 90% or higher. This is because the retention of moisture on the surface of soybeans, which facilitates the function of extracellular enzymes, is necessary for the growth of Bacillus natto and its nutritional intake. During this induction period (0 to 6 hours), the volatile ammonia gas is approximately constant at 1.4 ppm as shown in the attached table, and at 8 hours it becomes approximately 2.1 ppm, indicating that growth has progressed and entered the logarithmic phase. be done. In this logarithmic phase, Bacillus natto grows actively,
As shown in Figure 5, the fermentation heat began to rise rapidly,
The generation of ammonia gas also rapidly increased to approximately 10.5 ppm and entered a steady phase. During this stationary phase, the nutrients in soybeans are gradually consumed by Bacillus natto and growth decreases. In addition, at this time, in order to form mucilage peptides, each device is driven based on the product temperature data from the product temperature sensor 32, and the room temperature is controlled at around 48°C to 52°C depending on the type of soybean. Along with being
In order to increase the strength of the mucilage and concentrate the taste, the indoor air is gradually dehumidified by driving the supply/exhaust devices 23, 24 and the dehumidifier 26b so that the humidity at the end of the fermentation process is approximately the outside temperature. . From this stationary period, as the temperature rises due to fermentation heat, Bacillus natto gradually undergoes autolysis, the surface of the natto is covered with internal enzymes, and full-scale fermentation begins, with the release rate of amino acids increasing to around 0.6%. Enter the formation of natto's unique flavor. At the same time, quantitatively, the generation of ammonia gas gradually increased and reached over 14.0 ppm, making it possible to confirm the appropriate timing of completion of fermentation. In the death period (ripening period), the target ammonia gas concentration reaches 14.0 ppm, and the cooling device 25 is controlled to rapidly lower the room temperature. As a result, fermentation of natto is suppressed, and sufficiently ripened natto can be maintained at the desired quality and stored without overdecomposition. In this way, by controlling the room temperature and humidity based on the amount of ammonia gas generated by soybeans, it is possible to directly control the promotion or suppression of amino acid production that has a correlation with ammonia gas. Therefore, it is possible to manufacture natto while knowing the degree of ripening of the natto during the fermentation process, and the quality can be directly controlled in the natto manufacturing process, making it possible to manufacture natto according to taste. In the above embodiment, control was performed only based on the amount of ammonia gas generated, but control may be performed in combination with other factors. (Effects of the Invention) As explained above, according to the present invention, natto is manufactured by controlling the temperature and humidity in the fermentation chamber based on the amount of ammonia gas generated.
It is possible to manufacture natto while knowing the degree of ripeness of natto that occurs during the fermentation process, and it is possible to directly control the quality even during the production of natto.
In addition, the amount of ammonia gas generated varies depending on the characteristics (size and quality) of the raw soybeans, but since the amount of ammonia gas generated is used as a control parameter, it is possible to produce natto according to the characteristics of the raw soybeans, and fermentation It is possible to produce natto according to your taste, almost unaffected by the size of the chamber, the amount of preparation, or the characteristics of the raw materials.

[Brief explanation of drawings]

Figures 1 to 5 relate to the present invention; Figure 1 is a schematic diagram of a natto manufacturing device, Figure 2 is a schematic diagram of its control device, and Figure 3 is a schematic diagram showing the proteolysis process by microorganisms; FIG. 4 is a schematic diagram of a control flow, FIG. 5 is a diagram showing an example of control characteristics of room temperature and humidity, and FIG. 6 is a schematic diagram showing an example of a conventional program control flow. 21... Fermentation chamber, 22a, 25... Heating/cooling device, 26a, 26b... Humidifying/dehumidifying device, 28... Stocking box (container), 34... Gas detection means (mass spectrometer), 40... Control Device.

Claims (1)

[Scope of Claims] 1. Soybeans inoculated with Bacillus natto and put into a preparation box in a fixed amount are placed in a fermentation chamber equipped with at least a heating/cooling device and a humidifying/dehumidifying device, and the room temperature and humidity in the fermentation chamber are controlled. In the method for producing natto, the amount of ammonia gas generated from the soybeans during the fermentation process is detected by a gas detection means, and each of the devices is driven by a control device based on this detection data. A method for producing natto, which comprises controlling the room temperature and humidity in the fermentation chamber. 2. In a natto production device that ferments soybeans inoculated with natto bacteria and placed in a preparation box in a fixed amount in a fermentation chamber to produce natto, a heating and cooling device is installed in the fermentation chamber to heat or cool indoor air. a humidifier/dehumidifier for humidifying or dehumidifying a room, a gas detection means for detecting the amount of ammonia gas generated from the soybeans during the fermentation process, and each of the above devices based on detection data from the gas detection means. A natto manufacturing device comprising: a control device that controls room temperature and humidity in a fermentation chamber by driving the fermentation chamber.