JPH0441587B2 - - 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. 4, for example. In this control, the sixth
As shown in the figure, first, pre-cooling, germination propagation, fermentation, and strong cooling predetermined times, temperature, and humidity in the fermentation process are set in the controller based on empirical values, and fermentation control is started by the start switch. In fermentation control, a heating/cooling device, a humidifying/dehumidifying device, and an air supply/exhaust device provided in the fermentation chamber are driven based on detection data from each room temperature sensor, humidity sensor, product temperature sensor, etc. arranged in the room. 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 was manufactured based on 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 to be prepared, the characteristics of the raw soybeans (size, 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 measuring the amount of oxygen consumed and the amount of carbon dioxide gas increasing as natto grows, and controlling room temperature and humidity based on this data, it is possible to directly control the progress of natto production, making it possible to adjust the production according to taste. The purpose is to enable the production of natto. (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 controlling the room temperature and humidity in the fermentation chamber, the amount of oxygen consumed by the growth of natto bacteria and the amount of carbon dioxide that increases during the fermentation process is controlled by gas. The natto manufacturing apparatus according to the second aspect of the present invention is configured to detect the fermentation by a detection means, and to control the room temperature and humidity in the fermentation chamber by driving each of the devices by a control device based on the detection data. In a natto production apparatus 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 provided in the fermentation chamber to heat or cool indoor air. , a humidifier and dehumidifier that humidifies or dehumidifies a room, a gas detection means for detecting the amount of oxygen consumed by the growth of Bacillus natto and the amount of carbon dioxide gas increased during the fermentation process, and detection data from the gas detection means. and a control device that controls the room temperature and humidity in the fermentation chamber by driving each of the devices based on the following. The reason why the temperature and humidity inside the fermentation chamber were controlled based on the amount of oxygen consumed and the amount of carbon dioxide gas increased in the fermentation chamber was based on the following knowledge. In other words, during the process of fermenting natto in a fermentation chamber, soybean protein is gradually broken down by proteolytic enzymes produced by the growth of the inoculated natto bacteria, which is then broken down into water-soluble proteins and then into amino acids. Ru. On the other hand, the growth and proliferation of Bacillus natto is
As shown in the chemical formula below, the glucose in the soybean undergoes an oxidation reaction that is accelerated, generates fermentation heat, generates carbon dioxide gas, and completes the fermentation. C ₆ H ₁₂ O ₆ +6O ₂ →6CO ₂ +6H ₂ O + 787Kcal Such reactions occur one after another in a power order during the fermentation process, and the amount of oxygen in the container E, the amount of carbon dioxide gas D, and the amount of oxygen in the fermentation chamber F are For example, it is known that the state of growth and proliferation of Bacillus natto can be estimated from the correlation by detecting the amount of consumed oxygen and increased amount of carbon dioxide gas, as shown in Figure 4. While recognizing the fermentation process, it can be immediately linked to fermentation control. Therefore, by detecting the amount of oxygen consumed and the amount of increased carbon dioxide gas during the fermentation process, it becomes possible to control the production while directly controlling the quality in the fermentation process of natto. (Function) Therefore, by finally detecting the amount of oxygen consumed during the fermentation process and the amount of carbon dioxide gas increasing by the produced gas detection means, and comparing it based on the amount of produced gas known in advance. , it is possible to know the progress of fermentation during the production process, which was previously impossible to grasp numerically, by driving each device installed in the fermentation chamber.
By controlling the room temperature and humidity in the fermentation chamber, it is possible to suppress or accelerate natto fermentation while checking the progress of fermentation. (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 intake device 23 that introduces outside air into the room and an exhaust device 24 that exhausts indoor air to the outside are provided at the upper part of the outside.When necessary, outside air is taken into the room through the 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 (MCU) 45, and a room temperature during the fermentation process.
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, and ionizes atoms and molecules of oxygen and carbon dioxide to be measured from the introduced air in an electromagnetic field. The mass is measured based on the trajectory of the sampled oxygen and carbon dioxide components, and the concentration values of the sampled oxygen and carbon dioxide components are 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. 3 is performed. That is, based on the gas amount data of oxygen and carbon dioxide detected by the mass spectrometer 34 and the product temperature data from the product temperature sensor 32, heating is performed while indoor air is being circulated by driving the ventilation circulation device 22. 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. and humidity are controlled, for example, as shown in FIG. In addition, the indoor humidity, product temperature, and room temperature will be
The detection data is detected by each sensor 30, 31, and 32 and recorded in a recorder, and the indoor air during the fermentation process is introduced through an introduction pipe 33, and the concentration of oxygen and carbon dioxide is detected by a mass spectrometer 34. Based on this detection data, the amount of oxygen currently consumed and the amount of carbon dioxide gas that has increased can be detected based on the data inputted in advance to the MCU (microcomputer) 45. It is known that the consumed oxygen amount and increased carbon dioxide amount change over time, as shown in the attached table, for example. Therefore, the start and end points of each control period can be detected by changes in these amounts, and the fermentation process can be controlled. Note that the amount of these gases varies depending on the characteristics of the soybean, such as its size and quality (carbohydrate content), and the gas generation or consumption pattern varies.

[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-mentioned quality coefficient has a correlation with the amount of consumed oxygen and increased carbon dioxide, for example, the release rate of amino acids and other produced substances, factors having these relationships can be used as a standard for product quality. Therefore, 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 supplying 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, the amount of carbon dioxide in the container (preparation box) is 0.
At ~2 hours, it was as low as 0.2%, at 4 hours, it was 0.8%, and at 6 to 8 hours, it rapidly increased to 6.9% to 23.7%. In contrast, the amount of oxygen in the container rapidly increased at 6 to 8 hours. It is detected that the growth of Bacillus natto has progressed and entered the logarithmic phase. In the logarithmic phase, Bacillus natto proliferates vigorously, and the fourth
As shown in the figure, the fermentation heat begins to rise rapidly as the glucose oxidizes. It is known that in order to raise the temperature of 100 g of soybeans by 1°C per hour, approximately 20 ml of oxygen is required and approximately 100 ml of supplied air is required for this fermentation heat. Therefore, oxygen is supplied into the fermentation chamber 21 by driving the supply and exhaust devices 23 and 24 and introducing outside air. In this case, the amount of oxygen in the fermentation chamber is as shown in the attached table, despite the introduction of outside air.
The amount of carbon dioxide gradually decreased to about 3%, and the amount of carbon dioxide gradually decreased to 20%.
It reaches a certain level and enters the stationary 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. It will be done. From this stationary period, as the temperature rises due to the fermentation heat, the natto bacteria gradually undergoes self-digestion, and the surface of the natto is covered with internal enzymes, and full-scale fermentation begins, increasing the release rate of amino acids and creating the unique flavor of natto. begins to form. At the same time, the amount of oxygen decreases to about 1% and the amount of carbon dioxide gas decreases to about 12%, making it possible to confirm the proper timing of completion of fermentation. During the death period (ripening period), 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 room temperature and humidity based on the amount of oxygen consumed by Bacillus natto and the amount of increased carbon dioxide gas, it is possible to grow and multiply Bacillus natto, which has a correlation with the amount of oxygen consumed and increased amount of carbon dioxide gas. Facilitation or inhibition can be directly controlled. 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 is performed only based on the amount of oxygen consumed and the amount of increased carbon dioxide, 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 consumed oxygen amount and increased carbon dioxide amount, so that natto is produced during the fermentation process. It is possible to manufacture natto while knowing the degree of ripeness of the natto produced, and it is possible to directly control the quality even during the production of natto. In addition, the amount of oxygen consumed and the amount of increased carbon dioxide gas vary depending on the characteristics (size and quality) of the raw soybeans, but since these gas amounts are used as control parameters, it is possible to produce natto according to the characteristics of the soybeans. This makes it possible to produce natto according to one's taste, almost unaffected by the size of the fermentation chamber, the amount of fermentation, or the characteristics of raw materials.

[Brief explanation of drawings]

1 to 5 relate to the present invention, in which FIG. 1 is a schematic diagram of a natto manufacturing device, FIG. 2 is a schematic configuration diagram of its control device, FIG. 3 is a schematic diagram of a control flow, and FIG.
The figure shows an example of room temperature and humidity control characteristics.
FIG. 5 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 oxygen consumed or the amount of carbon dioxide gas increased due to the growth of the natto bacteria during the fermentation process is detected by a gas detection means, and the control device controls the amount of oxygen consumed by the growth of natto bacteria during the fermentation process, and the control device A method for producing natto, comprising controlling the room temperature and humidity in the fermentation chamber by driving each of the devices. 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 and dehumidifier for humidifying or dehumidifying a room, a gas detection means for detecting the amount of oxygen consumed by the growth of Bacillus natto or the amount of carbon dioxide gas increased during the fermentation process, and a A natto manufacturing apparatus comprising: a control device that controls room temperature and humidity in a fermentation chamber by driving each of the devices based on detection data.