JPS5840036A - Drying of shiitake mushroom in dehumidified atmosphere at low temperature - Google Patents

Abstract

PURPOSE:To improve the quality, shape, and yield of dried SHIITAKE mushroom, by drying SHIITAKE in circulating low-humidity air produced by the mild heating of dehumidified air. CONSTITUTION:Air is cooled and dehumidified with the cooler 5, heated at about 40 deg.C with the reheater 3, sucked with the blower 6 through the path 3a, sent through the duct 10 and the path 12, heated mildly with the burner 7 to about 50 deg.C, introduced into the drying chamber 8 from the bottom to effect the drying of SHIITAKE contained in the chamber, exhausted from the chamber 8 through the duct 11 and the path 5a, and returned to the cooler 5 to form an air circulation circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of drying shiitake mushrooms, and in particular, a novel method of dehumidifying shiitake mushrooms that further improves quality, shape, and yield by circulating dehumidified air with slightly heated low-humidity air. It relates to a low temperature drying method.

Conventionally, shiitake mushroom dryers typically dry shiitake mushrooms by blowing air indirectly heated by combustion in a kerosene-fired combustion burner through shiitake mushrooms placed on shelves. However, when using this hot air drying method, air needs to be at a high temperature of about 60 to 65°C, which also consumes a large amount of kerosene.
Moreover, the drying results were not necessarily satisfactory in terms of quality, shape, and yield.

The present invention was made to improve the above-mentioned defects, and aims to obtain shiitake mushrooms with good quality, shape, and yield by drying with dehumidified low-temperature air.
A cooling dehumidifying device consisting of a cooler, a reheater, and an auxiliary heater, a cooler, a reheater, a blower, an auxiliary heater, a drying room,
A method for dehumidifying and low-temperature drying of shiitake mushrooms by forming an air circulation circuit that circulates ventilation in the order of the cooler, and controlling the blowing temperature at the outlet of the reheater to about 40°C and the blowing temperature at the outlet of the auxiliary heater to about 50'C. We aim to provide the following.

Examples of the present invention will be described below.

FIG. 1 shows a combination of a cooling and dehumidifying device, an auxiliary heater, and a drying chamber used in the method of the present invention.

Although the refrigerant circuit itself of the cooling and dehumidifying device is well-known, there are specificities in the arrangement of each device, the auxiliary heater, and the duct connection between the air circulation tank and the drying room.

First, the cooling and dehumidifying device includes a compression unit (A) housing a compressor (+) and a liquid receiver (4), an outdoor condenser (2),
A return path (5a) to the cooler (5) that houses the cooler (5), reheater (3), expansion valve (15), etc. and forms an air circulation path, a circulation circuit (9), and a reheat The refrigerant circuit consists of three units: a dehumidifying unit (B) that forms passages such as an outgoing passage (3a) from the compressor (3), and a dehumidifying unit (B) that connects the compressor (1
), the refrigerant branches into two, one is a solenoid valve (SV, )
to the condenser (2), the other to the reheater (3) via the solenoid valve (SV2), and the other to the condenser (2).

They each condense in the reheater (3) and enter the receiver (4),
The liquid enters the cooler (5) from the liquid receiver (4) via the expansion valve (!5), evaporates, returns to the compressor (1), and repeats this circulation.

At this time, in the dehumidifying unit (B), the air is cooled from the return passage (5a) by the cooler (5), and the air is cooled by the reheater (5).
3) is heated to a predetermined blowout temperature, and the outgoing passage (3a) is heated.
), and in order to control the temperature to the predetermined temperature, the solenoid valve (sv, ), (
thermostat Q3), which controls the opening and closing of sv2), (
14) are provided respectively.

On the other hand, (C) is a drying unit, and the unit (C) is a drying unit.
) is partitioned into a drying room (8) and a passageway (12) housing a blower (6) and a burner (7) equipped with a thermostat (7a) that detects the blowout temperature as an auxiliary heater. Inside the drying room (8), there are multi-tiered full-screen shelves (8a) on which shiitake mushrooms are placed. Moreover, the relationship with the dehumidifying unit (B) is that the outgoing path (3a) and the path (
12) is connected by a duct (10), and the outlet of the drying chamber (8) and the return passage (5a) are connected by a duct (II), forming an air circulation circuit.

That is, the air, which has been cooled and dehumidified by the cooler (5) and reheater (3) as described above and has reached a predetermined temperature, is sucked from the outgoing passage (3a) by the blower (6) and then passed through the duct (10). From the passageway (12), the burner (7) warms the mushrooms slightly to a predetermined drying temperature, and the mushrooms enter the drying chamber (8) from below, drying the mushrooms, and return from the exit of the drying chamber (8) through the duct (11). (5a) and enters the cooler (5) to form an air circulation circuit.

The following experiments were conducted using the above dehumidifying and low-temperature equipment.

Compressor (1) 2.2KW, cooler (5) heat transfer area 39-
6771'', reheater (3) transfer area 31.'7nr',
Refrigerant Freon 12, blower m,”,
Kcap (6) air volume 5/, burner (7) 30,00
0 //H, thermostat 1-(13L (14)) that detects the outlet temperature of the reheater (3) is heated to 40'C.
Thermostats ('7a) that detect the outlet temperature of the burner (7) were set at 50°C, and raw shiitake mushrooms (variety: Kashin, harvesting condition: Uchiko) with a total weight of 16.5 kg were placed in a drying room ( 8) It was placed inside and dried. When I took out the shiitake mushrooms after 7 hours of operation, which was about the same as before, the total weight was 2.5
Kg, the yield has been greatly improved to 15% (normally 10%), the shape is good, the wrinkles on the cap, the gloss, and the folds are better than before, and the kerosene consumption is also lower than that of the burner (7).
At startup and during normal operation, the temperature increases by approximately 10'C to approximately 50°C.
Since it is only necessary to maintain the amount at 1.01, the amount is only about 1.01.

In addition, when we examined the state of the mushrooms, we found that according to the method of the present invention, the mushrooms recovered almost as fresh as fresh shiitake mushrooms when immersed in boiling water at 70'C for about 30 minutes, but this was not the case with the conventional hot air drying method. When the broth was analyzed, the chemical components were as follows.

Conventional (771 g) Present invention (msQ magnification uridylic acid 109.1 165.4 1.5 cytidylic acid 62.6], O'i', 3.1.'7
Abenyl acid 55.4 114.8 2.1 Inosinic acid 31.5 186.1 5.9 Guanylic acid 90.2 159. '7 18 (Note) The above content indicates the amount in 100g of broth.

Among the above results, it was found that the residual content of inosinic acid and guanylic acid, which give the taste of bonito flakes and shiitake mushrooms, was significantly higher than that of the conventional method.

The above is an experimental example in which the outlet temperature of the reheater (3) was 40°C and the outlet temperature of the burner (7) 1 was 50'C. The reason for setting the blowing temperature to about 50'C is that if it is set to about 60'C as in the conventional example, good quality and shape results cannot be obtained, and if the blowing temperature is set to about 40'C, it will be too low and dry. This is based on the experimental results that it takes too much time and is not economical.Furthermore, setting the outlet temperature of the reheater (3) to 40'C may seem too high, but the above-mentioned Since the air is circulated, the temperature of the return air decreases little during the circulation process, and high-temperature dehumidified air can be easily obtained without increasing the heat exchange area of the reheater.

As detailed above, in the dehumidifying and low-temperature drying according to the method of the present invention, drying is performed using an air circulation circuit that combines a cooling and dehumidifying device using a freezing device and an auxiliary heater, so that the circulating air is dehumidified beforehand. Since it is dried at a low temperature, fresh shiitake mushrooms are less likely to be damaged, and the capacity of the auxiliary heater is small, and the outlet temperature of the reheater can be set to 40°C.
Since the blowing temperature at the outlet of the auxiliary heater is controlled to about 50'C, the auxiliary heater only needs to be operated at the initial start-up and during operation to maintain the low temperature, resulting in significant energy savings. In addition, as mentioned above, the quality, shape, and yield of shiitake mushrooms after drying are significantly improved compared to conventional hot air drying due to dehumidification and low-temperature drying.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing a dehumidifying low-temperature drying apparatus used in the method of the present invention. (1)...Compressor, (2)...Condenser, (3)...Reheater, (4)...Cooler, (6)...Blower, (7)...
Auxiliary heater, (8)...Drying room. Patent applicant Toshin Kogyo Co., Ltd. Patent applicant Shizuoka Daikin Air Conditioning Co., Ltd. Patent applicant
Daikin Industries, Ltd.

Claims (1)

[Claims] (1) A cooling and dehumidifying device consisting of a compressor (1), a condenser (2), a cooler (4), a reheater (3), etc., and an auxiliary heater (7).
), cooler (4), reheater (3), blower (6),
An air circulation circuit is formed in which the auxiliary heater (7), the drying chamber (8), and the cooler (4) are circulated in this order, and the outlet temperature of the reheater (3) is set to about 40°C, and the auxiliary heater ( 7) A method for dehumidifying and low-temperature drying of shiitake mushrooms, characterized in that the blowing temperature at the outlet is controlled to about 50°C.