JPH0249785B2 - KOKURUINOSEN JOHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for washing grains when processing grains such as steaming, cooking, or milling.
By using liquefied carbon dioxide gas to wash grains, the inconveniences caused by washing with water, which is commonly practiced, are overcome.

When grains such as rice are cooked, it is necessary to remove bran and starch mixed in the grains or attached to their surfaces, and it is well known that this is usually done by washing with water. However, the method of washing with water requires a large amount of water when it is processed industrially, and the waste water has the disadvantage of causing pollution. That is, the waste water after washing has a very high BOD and contains oil, so it costs a lot of money to purify it. Another drawback is that bran, finely powdered starch, and taste substances such as sugars and amino acids flow out during washing, making it difficult to recover them.

Additionally, instead of washing with water, there is a method of increasing the degree of polishing by polishing, but the grains processed with this method have poor flavor and a strong bran odor, making it impractical to process them with waterless washing. Moreover, the yield of edible portions is poor and the grains may be destroyed, which is undesirable. Next, there is a method in which the oil is extracted and refined at the same time using an organic solvent such as n-hexane, but this method results in excessive degreasing, difficulty in separating the solvent from the raw material, and difficulty in completely removing the solvent. It is not preferable from a food hygiene perspective.

The above is mainly about the inconveniences and shortcomings of industrial processing of grains, but the same is true in the case of civil use as well, which causes pollution due to wastewater. Washing rice using water requires a considerable amount of water and is time-consuming, so if it were possible to supply grains, especially rice, that do not require washing with water for civilian use, it would be very effective. However, the conventional method of washing with water has been difficult to preserve, and has not been realized.

The present invention was devised as a result of various studies based on the above, and its feature is that by washing grains with liquefied carbon dioxide gas, the bran and starch mixed in the grains or attached to the surface of the grains are removed by liquefied carbon dioxide gas. This method separates and removes the rice bran and starch mixed in the liquefied carbon dioxide gas. This eliminates the above-mentioned inconvenience caused by washing with water, and also facilitates storage, resulting in advantages such as being able to cook rice without any effort.

An example of the implementation of the grain washing method of the present invention will be explained below using the drawings. 1 is a storage tank for grains, 2 is a washing tank having a pressure-resistant structure and is equipped with an agitator inside, and 3 is a washing tank after washing. This is a storage tank for storing grains and supplying them to processing steps (not shown) such as processing or packaging. Next, 4 is a solid-liquid separator that separates the bran and starch that are removed from the grains and mixed in the liquefied carbon dioxide gas, and 5 is a storage tank for the liquefied carbon dioxide gas. These tanks 1, 2, 3, 5 and the solid-liquid separator 4 are connected by pipes, and the flow path for grains is shown by a solid line, and the flow path for liquefied carbon dioxide gas is shown by a dotted line. .

Grain in the grain storage tank 1 is supplied to the washing tank 2 via a valve 6. When the amount of grain in the washing tank 2 reaches a predetermined amount, the valve 6 is closed, the valve 7 is opened, and liquefied carbon dioxide gas is introduced.
Cereals and liquefied carbon dioxide are brought into contact. When the agitator in the cleaning tank 2 is driven to stir the grains, the contact effect is further improved and the cleaning effect is enhanced. By this operation, bran and finely powdered starches are transferred to the liquefied carbon dioxide gas, and components with a bran odor such as n-hexanal, n-pentanal, and thiazole are chemically extracted by the liquefied carbon dioxide gas. When the cleaning operation by contacting with liquefied carbon dioxide gas under pressure is performed for a predetermined period of time, valves 8 and 11 are opened to guide the liquefied carbon dioxide gas to solid-liquid separator 4 . Then, the valve 11 is closed, the valve 9 is opened to transfer the grains in the washing tank 2 to the storage tank 3, and the valve 10 is opened to supply the grains for subsequent steps, such as processing or packaging. On the other hand, the liquefied carbon dioxide gas introduced into the solid-liquid separator 4 is circulated and used after separating bran, starch, etc. therein.

According to the method of the present invention, 1000 g of commercially available polished rice was washed in a pressure vessel equipped with a stirrer. At this time, 2000g of liquefied carbon dioxide gas was used and after a few minutes of operation, washed rice with a transparent white color and an excellent appearance was produced.
992g was obtained, and 8g of bran was obtained from liquefied carbon dioxide.
and fine powder were collected in dry form. This yield was better than equivalent washed rice obtained by conventional water washing. Next, the obtained rice was cooked in a conventional manner and subjected to a sensory test. There was no bran odor at all, and the flavor, appearance, texture, etc. were all good, compared to the same rice that had been washed and cooked. There was no difference at all.

In addition, when implementing the method of the present invention for relatively large-scale industrial use, by providing multiple cleaning tanks and controlling the supply of liquefied carbon dioxide gas, which is the cleaning liquid, to each tank, it is possible to reduce the amount of liquefied carbon dioxide per unit raw material. Gas consumption can be reduced. Further, since it is easy to keep the grain storage tank 1, washed grain storage tank 3, and solid-liquid separator 4 under a carbon dioxide atmosphere at all times, the quality of grains and recovered materials can be maintained. Moreover, if the grains in the washed grain storage tank 3 are sealed and filled in, for example, an impermeable bag while shielding from the atmosphere, they can be stored for a long period of time without causing deterioration in quality.

As described above, the method of the present invention organically combines the physical operation of cleaning grains by stirring and contacting them with liquefied carbon dioxide as needed, and the chemical operation of extracting the bran odor. The second feature is that the rice bran and starch transferred to the liquefied carbon dioxide gas are separated and recovered, and the liquefied carbon dioxide gas from which the rice bran and starch have been separated is recycled and used. , compared to conventional means, many effects such as the following can be expected. First, since there is no need for washing with water, there is no need for wastewater treatment, and labor savings associated with washing can be achieved. In addition, since the grains after washing can be stored for a long period of time, there is no need to wash them before processing even if they are used for civilian purposes, and the grains can be collected in a dry state after washing, making the next process or storage treatment easier. Next, the bran that conventionally flows out during washing and is not recovered.
Starches can be easily recovered in a dry state and can be used effectively. Furthermore, the outflow of water-soluble substances such as sugars, amino acids, and vitamin B1 is significantly reduced compared to washing with water, and items cleaned by the method of the present invention are characterized by a high water absorption rate when immersed in water. be.

As is well known, liquefied carbon dioxide gas is safe from a food hygiene perspective, and has a cleaning effect as well as being able to kill pests and their eggs in grains.
In addition, liquefied carbon dioxide gas can be obtained at a low cost, and by recycling it, the amount of consumption can be reduced, so that, together with the above-mentioned effects, it has great practical benefits.

[Brief explanation of drawings]

The figure is a flow diagram showing an example of an apparatus for carrying out the cleaning method of the present invention. 1... Grain storage tank, 2... Washing tank, 3... Storage tank, 4... Solid-liquid separator, 5... Liquefied carbon dioxide storage tank, 6, 7, 8, 9, 10, 11... Valve .

Claims (1)

[Scope of Claims] 1. Grains are brought into contact with liquefied carbon dioxide gas, and the bran, starch, etc. of the grains are washed out by the liquefied carbon dioxide gas and transferred into the liquefied carbon dioxide gas, and then the grains and the liquefied carbon dioxide gas are separated. A method for washing grains, characterized by: 2. Bringing the grains into contact with liquefied carbon dioxide gas, washing out the bran, starch, etc. from the grains with the liquefied carbon dioxide gas and transferring them to liquefied carbon dioxide gas, then separating the grains from the liquefied carbon dioxide gas, and then adding the grains to the liquefied carbon dioxide gas. A method for washing grains, which comprises separating and recovering transferred bran, starch, etc., and circulating and using liquefied carbon dioxide from which the bran, starch, etc. have been separated.