JPS5918030B2 - Cooling method for steamed grains - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cooling steamed grains,
The purpose of this is to prevent the solidification of particle surfaces that occurs during vacuum cooling and to efficiently cool the particles.

BACKGROUND ART Conventionally, in the food industry, particularly in the grain processing industry such as the brewing industry and the confectionery industry, it has been common to steam or cook grains instead of using them as they are.

Normally, steamed grains are cooled to an appropriate temperature and sent to the next processing step, but in these industries,
In particular, when inoculating grains after steaming with koji mold or other microorganisms and culturing them on a solid state, such as in the brewing industry or enzyme industry, it is necessary to strictly observe the appropriate cooling temperature, as the growth of the bacteria is affected by the cooling conditions. .

Conventionally, many methods are known for cooling grains after steaming.On a small scale, there is a method in which the grains taken out from the steamer are spread thinly on the floor and air cooled, but on a large scale, there is a method using a conveyor. It is common to provide ventilation cooling using various types of cooling devices or shaped horizontal cooling devices.

Furthermore, since the grain after steaming is at a high temperature and contains a large amount of water, it is also known to place the grain in a closed container 1 and reduce the pressure to cause self-evaporation, thereby cooling the grain adiabatically.

This vacuum cooling is extremely efficient and can cool large amounts of steamed grains in a short period of time, reducing the cooling temperature.

This is an extremely convenient method because the degree of pressure reduction can be controlled by the degree of vacuum, but on the other hand, it also has drawbacks.

That is, the dehydration rate is rapid, and the dehydration occurs through self-evaporation, resulting in a dry state with a cracked surface.

This is due to the moderate surface moisture of the steamed grains cooled on the floor,
The quality is significantly inferior to that of refrigerated materials that have a ridge.

When such a cooled material is used to inoculate Aspergillus or the like, there are disadvantages such as poor adhesion of spores and poor development of hyphae.

For this reason, although vacuum cooling is ideally desirable, such drawbacks in the cooled material hinder its practical application.

The inventor of the present invention conducted research to eliminate the problem of the grain surface becoming loose and solidified, which is a disadvantage of vacuum cooling, and discovered that the inventor placed steamed grains in an airtight container and circulated the air inside the container to create a reduced pressure state. Cooled air is produced using a cyclone that exchanges heat while spraying water, or air containing a large amount of moisture or an inert gas such as carbon dioxide, nitrogen gas, or argon gas is blown in and circulated to reduce the pressure. The problem could be solved by cooling the product substantially only by the internal gas using the closed steaming system at normal pressure or pressurization.

That is, the more the pressure is reduced in the airtight container, the more water evaporates and the temperature of the grain particles themselves is lowered, but if the pressure is reduced to a certain extent and the particles are cooled, a hard film will form on the surface and the particles will become loose.

At this time, during cooling, air containing a large amount of moisture or an inert gas such as carbon dioxide gas or nitrogen gas is injected and circulated while cooling while passing between the grain particles, thereby completely preventing the surface solidification phenomenon. .

The present invention will be explained with reference to the accompanying drawings. Reference numeral 1 denotes a closed steamer, which is usually a normal pressure cooker or a high pressure cooker.

The pot is also designed to withstand vacuum, and is provided with an outlet (not shown) on the side.

A wire mesh 2 is provided inside a closed steaming pot 1, and grains A to be steamed are stored and placed above the wire mesh 2.

In addition, a steam extraction conduit 4 is opened above the steamer 1, and a conduit 3 is opened below, so that steam is blown in from below and steams the grain A through the wire mesh 2, so that air or steam flows out into the conduit 4 above. It is.

A first cyclone 5 is fixed to the other end of the conduit 4, and a fountain pipe 6 is provided inside the cyclone 5. The fountain pipe 6 is connected to a water supply pipe 7 to supply hot or cold water into the cyclone 5 from a fountain hole 8. It's like a fountain.

Further, the cyclone 5 has a drain pipe 9 below, and about 107
A water tank 10 is placed on the lower blade 71 so that the end of the drain pipe 9 is always sealed with water.

A conduit 11 is raised from approximately the center of the first cyclone 5,
The other end is opened to the second cyclone 12.

The second cyclone 12 opens the steam pipe 13 by following the lateral force in the tangential direction, and causes the conduit 3 to rise from the center thereof.

Further, a drain discharge pipe 14 is provided below the second cyclone 12.
and a valve 15 are provided to enable drain discharge and isolation from outside air.

16 is a fan installed in the middle of the conduit 3, 17 is a branch pipe installed in the conduit 4, and 18, 19°20.2L22 are valves installed in the conduit 3, conduit 4, branch pipe 17, conduit 11, and drain pipe 9, respectively. It is.

During operation, the grains A to be steamed are first placed on the wire mesh 2, the steamer 1 is hermetically sealed, the valves 18, 19 and 20 are opened, and the valves 21 and 22 are closed.

Next, when steam is blown into the second cyclone 12 from the steam pipe 13, the water droplets in the steam fall downward, and the steam passes through the conduit 3 and the valve 18, enters the steamer 1, and rises to feed the grains A. Steam.

At this time, the air in the steamer 1 is discharged through the branch pipe 17, and the entire system is filled with steam.

Next, the valve 20 is closed, the valve 21 is opened, and the fan 1
When 6 is operated, steam is circulated and steamed in a short time.

When the steaming is completed, the fan 16 is operated to circulate the internal gas without supplying steam while keeping the entire system in a closed state.

Then, the internal steam is condensed in a cyclone or the like within the system, and the pressure in the system is rapidly reduced, water vapor starts to evaporate from the steamed grains, and the temperature of the steamed grains quickly decreases.

When the temperature of the steamed grains has decreased to a certain extent, the water supply pipe 7
The temperature of the cooked grain can be further reduced by opening the oven and sprinkling cold water on it.

The degree of dehydration and cooling in the present invention is adjusted depending on the type and particle size of grains such as rice, wheat, and soybeans, but if vacuum cooling is continued beyond a certain point, the particle surface will become stiff and loose, so it will not be possible to achieve the desired result. When the degree of cooling is reached, while injecting water from the fountain pipe 6, the desired amount of air or inert gas is introduced by opening the valve 20, and the first cyclone is heated by the fan 16 under normal pressure, increased pressure, or reduced pressure. 5→The gas is circulated from the second cyclone 12 to the steam conduit 3 to the steamer pot 1.

During this circulation, the water in the gas is condensed by the jet water of the first cyclone 5, cooled and dusted, and the gas becomes saturated at that temperature.The second cyclone 12 removes floating water droplets, and the gas reaches the steaming pot 1 where it is steamed. Cool A.

For this reason, since the steamed grains are cooled with the moist gas, the cooling is not carried out rapidly, but is cooled while maintaining a balance with the moisture diffusion rate within the grain particles.

Therefore, according to the cooling method of the present invention, unlike conventional vacuum cooling, the particles are not cooled all at once, so the particle surfaces do not become bulky.

As described above, the present invention involves the process of vacuum cooling, and when a predetermined cooling temperature is reached, the cooling gas containing moisture is circulated under reduced pressure to perform cooling. It has advantages.

In the above explanation, an example of direct vacuum cooling from the steaming pot 1 was shown, but the steaming equipment may be provided separately and a closed container for cooling may be used in place of the steaming pot 1. Further, the drain pipe 9 may be shortened and connected to a wet pump.

The steamed and cooled product obtained by the method of the present invention is no different from the cooled product that is slowly cooled by normal pressure ventilation, and has the advantage of low moisture content, and is suitable for steaming and cooling in the brewing industry, confectionery industry, and other grain processing industries. It has been used with very favorable results.

[Brief explanation of the drawing]

The drawings show an example of implementation of the invention. 1... closed steamer, 2... wire mesh, 3...
...Steam blowing pipe, 4...Steam extraction pipe, 5...First cyclone, 9...
Drain pipe, 12...Second cyclone, 13...
...Steam pipe, 16...Fan.

Claims (1)

[Claims] 1. The inside of a closed steaming pot or closed container containing steamed grains is depressurized and cooled, and then the gas discharged from the pot or container is introduced into a cyclone that exchanges heat while spraying water. introducing a cooled gas saturated with moisture into the kettle or container, causing it to pass through the grain layer, and circulating it through the closed system to humidify and then cool the steamed grain. Characteristic cooling power method for steamed grains.