JPH06113761A - Production of nonwashing rice - Google Patents

Abstract

PURPOSE:To provide nonwashing rice needless to wash, also capable of improving its polishing yield. CONSTITUTION:In an extraction tank 12, rice 10 is brought into contact with liquid carbon dioxide or carbon dioxide in a supercritical state to extract the lipid component in the rice 10 into the carbon dioxide to effect dissolution of such component in the carbon dioxide. The pressure of the resultant carbon dioxide is reduced using a backpressure valve 16 and the carbon dioxide is brought to the inlet of a separatory tank 14 where the lipid component is separated from the carbon dioxide because the depressurized carbon dioxide less dissolves the lipid component. The carbon dioxide freed from the lipid component is passed through a filter 20, an activated carbon adsorption column 22, into a condenser 24 where it is liquefied again and returned to a high-pressure pump 26. With such carbon dioxide circulation, the lipid content of the rice can be reduced to about 0.8wt.%, a level attained by further washing normal polished rice (89-90% in polishing yield).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing non-washed rice, and more particularly to a method for producing non-washed rice by defatting the lipid content of rice.

[0002]

2. Description of the Related Art Generally, mowed rice is threshed and then unhulled to become brown rice. Brown rice contains about 3% of lipid content, and most of it exists in the surface layer of brown rice, and this lipid content is a factor that reduces the taste of rice. For this reason, brown rice is usually put on a rice polishing machine and the surface layer of brown rice is 10%.
About 90% of rice yield is scraped off, and the rice with the lipid content of brown rice reduced from 3% to 1% is sold.

By the way, the bran is the one that has been scraped off by milling and turned into a powder. When cooking rice that has been polished in this way, the rice is washed with water, the bran that has adhered during rice polishing is washed off, and then a certain amount of water is added to the rice for cooking. In a place like a cafeteria of a factory, washing rice is not only time-consuming, but waste water generated by washing rice has a high BOD due to the bran, which causes environmental pollution of rivers and the like. The same applies to the rice rinsing wastewater generated at home.

From such a background, Japanese Patent Publication No. 02-265
As disclosed in Japanese Patent No. 448, there is a method in which brown rice is polished, washed with water and dried, and then sold so that it can be used as it is without being washed when cooking rice.

[0005]

However, the conventional techniques have the following drawbacks. (B) The method of selling brown rice that has been polished, washed with water and dried so as to prevent waste water from washing during rice cooking is liable to cause cracks in the rice during the drying process, and is inferior in commercial value. There is no change in the waste water of rice washing from the washing step. (B) In order to reduce the lipid content of brown rice from about 3% to about 1%, it is necessary to scrape about 10% of the surface layer of brown rice in the rice polishing process of brown rice. Although the bran generated by scraping off the surface layer of brown rice contains 4-5% of sugar, it is discarded as bran, leading to a decrease in rice utilization.

In addition, 80% of vitamin B ₁ which is a nutrient is removed by polishing rice, and further, it is mostly lost by washing rice, which is a cause of lowering nutritional value not only by polishing rice but also by washing rice. Thus, the polished rice has improved taste and digestion and absorption rate, but the yield of polished rice is deteriorated and the nutritional value is considerably reduced as compared with brown rice. Therefore,
Although germinated rice and rice with vitamin B ₁ enrichment are sold,
In terms of taste and price, it is hard to say.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing non-washed rice which does not require washing and can improve the yield of polished rice.

[0008]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention comprises contacting a rice obtained by milling brown rice with a predetermined yield with liquid carbon dioxide in a liquid or supercritical state to obtain a lipid content of the rice. Is extracted with the carbon dioxide, and the lipid component is dissolved in the carbon dioxide.

[0009]

According to the present invention, carbon dioxide has a pressure of 50 to 30.
The conditions of 0 kg / cm ² and temperature 0 to 100 ° C. are applied,
The carbon dioxide is brought into a liquid state or a supercritical state. next,
Rice obtained by milling brown rice to a predetermined yield is contacted with carbon dioxide having the above conditions to extract the lipid content of the rice into the carbon dioxide and dissolve the lipid content in the carbon dioxide.

As a result, the lipid content of the rice is defatted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the method for producing non-washed rice according to the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIG. 1, the extraction tank 12 as a pressure-resistant container for extracting and dissolving the lipid content of the rice 10 in carbon dioxide, and the lipid content of the rice 10 is separated from the carbon dioxide in which the lipid content of the rice 10 is dissolved. A separation tank 14 is provided as a pressure resistant container.

The outlet of the extraction tank 12 is connected to the inlet of the separation tank 14 by a pipe 18 through the back pressure valve 16, and the outlet of the separation tank 14 is connected to the filter 20 and the activated carbon adsorption tank 2
2, a condenser 24, a high-pressure pump 26, and a heat exchanger 28, and is connected to the inlet of the extraction tank 12 by a pipe 30 to form a carbon dioxide circulation system passage. A liquefied carbon dioxide cylinder 32 is connected to the inlet of the high-pressure pump 26 by a pipe 34 to supply carbon dioxide to the circulation system passage.

Next, the operation of the apparatus thus constructed will be described. First, the rice 10 obtained by milling brown rice to a predetermined yield is put in the extraction tank 12 in advance. Then, a high-pressure pump 2 for supplying carbon dioxide from the liquefied carbon dioxide cylinder 32
6, the carbon dioxide is pressurized to a predetermined pressure, and then sent to the heat exchanger 28. In the heat exchanger 28, the carbon dioxide is heated to a predetermined temperature and supplied to the extraction tank 12.

In the extraction tank 12, the extraction tank 12 is previously
The rice 10 stored in the above is contacted with the carbon dioxide, and the lipid content of the rice 10 is extracted into the carbon dioxide and the lipid content is dissolved in the carbon dioxide. The carbon dioxide in which the lipid content of the rice 10 is dissolved is the back pressure valve 1
6, the pressure of the carbon dioxide is reduced by the back pressure valve 16, gasified, and then sent to the separation tank 14.

Since the gasified carbon dioxide has a low solubility of lipids, the gasified carbon dioxide sent to the separation tank 14 separates the dissolved lipid component from the separation tank 1.
4 (the lipid content separated in the separation tank is shown in FIG.
Designated by reference numeral 36). The gasified carbon dioxide from which the lipid content has been separated in the separation tank 14 is sent to the filter 20 and the activated carbon adsorption tower 22, and the impurities that are entrained during the extraction are removed and then liquefied again in the condenser 24 to obtain a high pressure. Pump 2
Return to 6.

As described above, the lipid content of the rice 10 can be defatted by circulating carbon dioxide in the above device under predetermined conditions. [Example] An example of defatting lipid components from rice using the above-mentioned device is shown below. Koshihikari brown rice from Chiba, rice yield 8
Rice that had been milled to 7% to 100% (brown rice) was prepared as a sample.

In addition, in the extraction tank, the lipid content of the rice is extracted and dissolved in carbon dioxide to give a pressure of 250 kg / cm ² and a temperature of 35.
The condition of ° C was applied to make the supercritical state. Further, the amount of carbon dioxide contacting the rice was 5 kg of carbon dioxide for 1 kg of rice. The results of treating the rice with the above apparatus under the above conditions are shown in FIG.

The curve A shown by white circles in FIG. 2 shows the relationship between the lipid content of the rice treated by the above-mentioned apparatus and the rice polishing yield, and the curve B shown by black circles shows the relationship between the rice treated by the conventional rice polishing method. It shows the relationship between the amount of lipids and rice yield. Normal white rice (polished rice yield 89-90%) has a lipid content of about 0.8% after further washing, and so-called non-washed rice has a lipid content of about 0.8%. Then, in the case of the method according to the present invention, if the rice adjusted to a rice polishing yield of 93 to 95% is treated under the above apparatus and under the above conditions, the lipid content of the treated rice will be about 0.8%. You can

That is, even if the rice is from 5 minutes to 7 minutes, the amount of lipid is the same as that when the normal white rice (rice polishing yield 89 to 90%) is washed. As is clear from this result, according to the method of the present invention, the rice polishing yield can be increased by 4 to 5% as compared with the conventional method, so that the utilization rate of rice is improved. In addition, the content of vitamin B ₁ in rice with a rice polishing yield of 93 to 95% is 0.31 to 0.40%, whereas vitamin B ₁ is largely lost after washing with the conventional rice polishing method. According to the method of the present invention, more than half of the brown rice remained, which was excellent in nutritional value.

[0020]

As described above, according to the method for producing non-washed rice according to the present invention, by contacting the brown rice polished with a predetermined yield with carbon dioxide in a liquid or supercritical state. , The lipid content of the rice is converted to normal white rice (polished rice yield 8
9 to 90%) can be defatted to a lipid content of about 0.8% when the rice is further washed, so that the rice can be cooked without being washed.

Further, in order to reduce the lipid content of rice at the time of rice polishing,
The rate of scraping off the surface of brown rice is small, the yield of polished rice can be increased, the utilization rate of rice can be improved, and the residual rate of vitamin B ₁ is high, so that rice with high nutritional value can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for producing non-washed rice according to the present invention.

FIG. 2 is a diagram showing the relationship between lipid and rice yield showing the effect of the present invention.

[Explanation of symbols]

 10 ... Rice 12 ... Extraction tank 14 ... Separation tank

Claims (3)

[Claims] 1. A method in which rice obtained by polishing brown rice to a predetermined yield is contacted with carbon dioxide in a liquid or supercritical state, and the lipid content of the rice is extracted and dissolved with the carbon dioxide. Method for manufacturing washed rice. 2. The carbon dioxide in the extraction step has a temperature of 0.
Under the conditions of ~ 100 ° C and pressure of 50-300 kg / cm ² ,
The method for producing non-washed rice according to claim 1, which is in a liquid state or a supercritical state. 3. The method for producing non-washed rice according to claim 1, wherein after extracting and dissolving the lipid content of the rice, the pressure of the carbon dioxide is reduced to separate the lipid content from the carbon dioxide.