JPH0153018B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing dried shiitake mushrooms, and an object of the present invention is to enable efficient and economical production of high-quality dried shiitake mushrooms. In the conventional method, dried shiitake mushrooms were produced by hot air drying, which resulted in condensation on the shiitake mushrooms on the leeward side, half-cooked mushrooms, discoloration, and loss of scent before drying. In addition, there were many cases where dried shiitake mushrooms were not suitable for long-term storage due to insufficient drying. Moreover, in the hot air drying method, there is a lot of heat loss that is released into the atmosphere, and the operating cost is high. In addition, if you want to increase the dehumidified air temperature step by step according to the degree of dryness of the shiitake mushrooms for efficient finishing drying,
It is difficult to adjust the temperature automatically and appropriately. In order to eliminate the above-mentioned drawbacks, the present invention first dehumidifies and dries the air in the shiitake drying room using a refrigerator and circulates it to the drying room, thereby preventing the shiitake mushrooms from condensation, half-cookedness, discoloration, odor loss, etc. Make it difficult to wake up. By using the cold energy of the cold air dehumidified by the evaporator of the refrigerator to pre-cool the air before it enters the evaporator through heat exchange, the cold energy generated by the evaporator is reduced to the dew point. To increase the amount of heat used for dehumidification by reducing the amount of heat consumed for cooling to a temperature of 100 degrees and increase the amount of heat used for dehumidification, thereby increasing the dehumidifying ability and thermal efficiency. Furthermore, while ensuring the permissible temperature of the air at the inlet of the evaporator, the temperature difference between the air being cooled in the cooling section of the heat exchanger before reaching the evaporator is drawn from the drying room into the dehumidifier. The permissible temperature of the air for drying can be made higher than the above-mentioned certain value, and the dehumidified air supplied to the drying room can be raised to a sufficiently high temperature without disturbing the refrigerator during finishing drying, so that shiitake mushrooms can be quickly finished to a high quality. This allows it to dry. DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of dryers and implementation procedures for carrying out the present invention will be described below with reference to the drawings. Fig. 1 shows an outline of a dryer D for producing dried shiitake mushrooms, in which fresh shiitake mushrooms 2 contained in breathable containers are housed in a stacked manner in a drying chamber 1 having a sealed and insulated structure, and a dehumidifier H consisting of a refrigerator R. Dehumidified and heated air is sent from the drying chamber 1 to the drying chamber 1 to dry the fresh shiitake mushrooms. The inlet 3 and outlet 4 of the dehumidifier H are opened in communication with the lower and upper parts of the drying chamber 1, respectively, and the dehumidified and heated air is pressurized by the blower 5 and circulated through the outlet 4 into the drying chamber 1. When flowing through the raw shiitake mushrooms 2, the moisture contained in the raw shiitake mushrooms 2 evaporates into the heated air, and the raw shiitake mushrooms 2 are dehumidified and dried. The dehumidifying air path P from the inlet 3 to the outlet 4 of the dehumidifying device H includes a cooling section 6 of a heat exchanger 6 in order from the upstream side.
A, the evaporator 7 of the vapor compression refrigerator R, the heating section 6B of the heat exchanger 6, the radiator 8 through which the compressed superheated liquid refrigerant of the refrigerator R flows at about 40 to 50°C, the blower 5, and the electric heater. Heating devices 9 consisting of the following are attached in series. Further, a damper 10 for adjusting the air volume is provided in the bypass air path P1. During the cycle of refrigerator R, numeral 11 is a compressor;
2 is a cooling tower, and 13 is an expansion valve. The heat exchanger 6 is, for example, a diaphragm type heat exchanger shown in FIG. 2, and has a structure in which corrugated metal plates are sandwiched between flat metal plates, oriented vertically and horizontally alternately. That is, the humid air that has absorbed moisture from fresh shiitake mushrooms 2 in the drying room 1 is sucked in through the suction port 3, the air volume is adjusted by the damper 10, and enters the cooling section 6A, where it is passed through the heat exchanger 6.
After being pre-cooled by the dehumidifying cold air flowing through the heating section 6B of
After being prewarmed by the uncooled warm humid air flowing therein, the air flows into the radiator 8 , where it is heated and then sent to the drying chamber 1 from the blower outlet 4 via the blower 5 . In the early stages of drying fresh shiitake mushrooms, the water content in the mushrooms is high, so to prevent them from becoming half-cooked, for example,
Drying is carried out by supplying dehumidified and heated air at a relatively low temperature of 30 to 35 degrees Celsius for about 18 hours. At the final stage of drying, the heating device 9 is operated to supply untempered high-temperature air heated to a higher temperature than before, for example, about 40 to 60° C., for about 6 hours for final drying. In other words, once the moisture content of shiitake mushrooms has decreased to a certain extent, even if the temperature of the drying air is increased, the mushrooms will not be partially boiled, discolored, or
High quality dried shiitake mushrooms can be produced without problems such as fragrance release. Note that the above-mentioned final drying may be performed in several stages. Table 1 shows an example of performance comparison calculation between the air dehumidifier of the above embodiment and a conventional air dehumidifier not equipped with the heat exchanger 6.

[Table] Since the present invention has the above configuration, it has the following effects. In other words, the air in the shiitake drying room is dehumidified and dried using a refrigerator and then circulated to the drying room, so of the shiitake mushroom layer to be dried, the moisture dehumidified from the shiitake mushrooms on the windward side is absorbed into the dehumidified air, and There is no condensation that adheres to the mushrooms on the side, and the shiitake mushrooms on the leeward side can be dried smoothly, with almost no half-cooking, discoloration, or loss of flavor.
Shiitake mushrooms can be dried to high quality. Moreover, the air inside the drying chamber circulates between the drying chamber and the refrigerator and is not discharged to the outside, so there is little heat loss.
Operating costs are lower, contributing to energy savings. In addition, the refrigerator can easily automatically control the temperature and humidity of the drying air, and automatically sets the optimal temperature and humidity conditions of the drying air according to the degree of dryness of the shiitake mushrooms, allowing them to be properly dried. Can be done. Further, by using the cold energy of the cold air dehumidified by the evaporator of the refrigerator, the air flowing into the dehumidifier from the drying room is cooled by heat exchange in the cooling section before reaching the evaporator. As a result, of the cold energy generated by the evaporator, the amount of heat consumed to cool the air to the dew point can be reduced, and the amount of heat used for dehumidification can be increased, increasing the amount of dehumidification and increasing the dehumidification capacity and thermal efficiency. In addition to increasing drying time and reducing drying time, it also reduces running costs and contributes to energy savings. At the same time, the cool air that passes through the heating section of the heat exchanger is heated by heat exchange with the uncooled air that passes through the cooling section, reducing the amount of heat required to heat the air with the radiator of the refrigerator. This also reduces running costs and contributes to energy savings. Furthermore, while ensuring that the allowable temperature of the air at the inlet of the evaporator is below a certain value to prevent overloading of the evaporator, the temperature at which the air is cooled in the cooling section of the heat exchanger before reaching the evaporator is also maintained. The permissible temperature of the air taken into the dehumidifier from the drying room can be made higher than the constant value by the difference in head. This allows the heating device to raise the dehumidified air supplied to the drying room to a sufficiently high temperature during final drying without causing problems due to overloading of the refrigerator, and allows the high-temperature dehumidified air to quickly produce high-quality shiitake mushrooms. Can be finished and dried.

[Brief explanation of drawings]

The drawings show an embodiment of a dryer for carrying out the present invention, and FIG. 1 is a schematic longitudinal sectional front view showing the overall configuration;
FIG. 2 is a perspective view of the heat exchanger. 1...Drying room, 2...Shiitake mushrooms, 3...Inhalation port, 4
...Air outlet, 5...Blower, 6...Heat exchanger, 6
A...6 cooling section, 6B...6 heating section, 7...
Evaporator, 8...Radiator, 9...Heating device, H...
Air dehumidifier, R...Refrigerating machine.

Claims (1)

[Claims] 1. The inlet 3 and outlet 4 of the dehumidifier H are connected to the shiitake mushroom drying chamber 1, and the dehumidifier H has a dehumidifying air path P and a bypass air path P1 from the inlet 3 to the outlet 4. From the windward side to the leeward side of the dehumidifying air path P, the cooling section 6A of the heat exchanger 6, the evaporator 7 of the refrigerator R, the heating section 6B of the heat exchanger 6, and the refrigerator R radiator 8,
A blower 5 and a heating device 9 are arranged in series, a damper 10 for adjusting air volume is arranged in the bypass air path P1 on the leeward side of the cooling section 6A, and this damper 10 is communicated with the blower 5 to dry. Fresh shiitake mushrooms 2 are stored in a chamber 1, and a blower 5 circulates air between the drying chamber 1 and a dehumidifying device H. In the dehumidifying device H, the air flowing from the drying chamber 1 to the inlet 3 is adjusted in volume with a damper 10. After that, the air is precooled in the cooling part 6A of the heat exchanger 6, further cooled and dehumidified in the evaporator 7 of the refrigerator R, the dehumidified air is prewarmed in the heating part 6B of the heat exchanger 6, and then After heating with the radiator 8 of the refrigerator R, the drying chamber 1 is discharged from the air outlet 4.
In the drying room 1, the fresh shiitake mushrooms 2 are dried with dehumidified air blown in from the outlet 4 of the dehumidifier H.
As a result, air containing moisture is sucked into the dehumidifying device H from the inlet 3, and at the end of drying of the fresh shiitake mushrooms 2, the dehumidified air produced by the dehumidifying device H is transferred to the heating device 9.
This method of producing dried shiitake mushrooms is characterized in that the shiitake mushrooms are heated to a higher temperature than before and then sent to a drying chamber 1, and the shiitake mushrooms are finished and dried with this dehumidified high-temperature air.