JPH04144655A - Method for modifying rice husk - Google Patents

Abstract

PURPOSE:To defat and deodorize rice husk without impairing sweet smell and flavor which rice husk has originally and modify the rice husk by treating rice husk with carbon dioxide kept in supercritical state or liquid state containing a specific amount of water content. CONSTITUTION:When rice husk is treated with carbon dioxide kept in supercritical state or liquid state or treated with a mixed solvent of carbon dioxide and at least one kind of hydrocarbon selected from 2-4C straight-chain carbon to modify the rice husk, water content not higher than the amount corresponding to saturated solubility according to the state of carbon dioxide or mixed solvent is added to carbon dioxide or mixed solvent.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for modifying rice grains, and more specifically, a method for modifying rice grains by defatting, deodorizing, etc. without impairing the aroma and flavor inherent in rice grains. Regarding how to ask questions.

[Prior art, invention or problem to be solved] Generally,
One of the factors that affects the taste (taste and odor) of rice grains
One example is the oils and fats contained in rice grains. Further, during the storage of rice grains, the oils and fats deteriorate and produce various substances, and in particular, free fatty acids and carbonyl compounds have a significant effect on the deterioration of the taste of rice grains. Furthermore, in brown rice,
Approximately 173 fats and oils are concentrated in the ridge, which not only prevents water absorption and makes processing difficult when cooking and processing brown rice, but also causes inconveniences such as deterioration of texture and taste. There was.

In order to eliminate these inconveniences, a method of treating rice grains with carbon dioxide in a supercritical or liquid state (Japanese Patent Laid-Open No.
9-78656), a method of treating rice grains with a mixed solvent of carbon dioxide and ethanol in a supercritical or liquid state (Japanese Patent Application Laid-open No. 133849/1984), and a method of treating rice grains in advance with a wetting agent such as water. , a method of contacting with pressurized carbon dioxide (Japanese Unexamined Patent Publication No. 156259/1983), etc. have been proposed. Furthermore, there is also known a method (Japanese Patent Laid-Open No. 64-56793) in which vegetable oils are extracted and separated from nuts and seeds containing vegetable oils by treatment with a mixed solvent of carbon dioxide and propane or n-butane.

However, although these methods make it possible to remove bad odors from rice grains, they also unavoidably result in the loss of the aroma and flavor inherent in rice grains, and they also require conditions that allow the aroma and flavor to remain. When using this method, there was a problem that the odor was not removed sufficiently.

[Means to solve the problem]

Therefore, the present inventors conducted repeated studies to develop a method for improving rice grains by defatting, deodorizing, etc. without impairing the unique aroma and flavor of rice, and arrived at the present invention.

That is, the present invention firstly provides that when rice grains are treated with carbon dioxide in a supercritical state or in a liquid state to be modified, water in an amount equal to or less than the saturated solubility corresponding to the state of the carbon dioxide is added to the carbon dioxide. The second method provides a method for reforming rice grains, which is characterized by treating rice grains in the presence of carbon dioxide in a supercritical or liquid state and carbon dioxide having a carbon number of 2.
When treating and reforming with a mixed solvent with at least one kind of hydrocarbon among the linear hydrocarbons of 4 to 4, water in an amount equal to or less than the saturated solubility depending on the state of the mixed solvent is added to the mixed solvent. The present invention provides a method for modifying rice grains, which comprises treating rice grains in the presence of The present invention will be explained in detail below.

First, there are no restrictions on the raw rice grain that is the object of the present invention, and any of 9-minute pounded brown rice, germ-polished rice, polished rice, etc. can be used.

Next, carbon dioxide is used as a solvent in the first invention,
In the second invention, a mixed solvent of carbon dioxide and at least one hydrocarbon among linear hydrocarbons having 2 to 4 carbon atoms is used. Here, the linear hydrocarbons having 2 to 4 carbon atoms are ethane, propane, and n-butane, and the mixing ratio (weight ratio) with carbon dioxide is, for example, CO2:itan=80
: 20-50 : 50, CO□propane = 90:
10-50:50, CO2: n-phytane”90:1
A value of 0 to 5050 may be used as a guide. That is, the lower limit of the amount of hydrocarbon added is the minimum amount that is recognized to be effective as a mixed solvent, and the upper limit is determined in consideration of safety.

Furthermore, there are no particular restrictions on the amount of carbon dioxide used, and in order to shorten the processing time, it is appropriate to use the amount of solvent used per hour at least five times the amount of rice filling. However, if too much solvent is used, it will lead to energy consumption and an oversized device, so it is usually preferable to set the upper limit to 15 times the amount. In addition, in the case of the second invention that uses a mixed solvent, the above values may be applied, and in either case, it should be in the range of 3 to 45 times the total amount of solvent used or the amount of rice filling. It is.

Furthermore, the amount of water used varies depending on conditions such as pressure and temperature during treatment. In other words, the conditions (pressure,
Depending on the temperature), the amount of water used is equal to or less than the saturated solubility of water in the solvent at that time.

Next, it is appropriate to set the processing conditions in the method of the present invention, particularly the pressure during extraction with a solvent to be in the range of 20 to 500 kg/d'-G, and the temperature to be in the range of -20°C to 70°C.

Next, after extracting oils and fats from rice grains, the conditions for separating the extract and the solvent are as follows: pressure 0 to 100 kg/
al-G, the temperature may be in the range of lo to 7o''c.

1 to 3 show flow diagrams of the apparatus used in carrying out the present invention. FIG. 1 shows a flow diagram of an apparatus employed when adding water to a solvent quantitatively from outside the system using a pump. Water is quantitatively introduced into the system from the storage tank 5 by a booster pump 6.

The solvent is supplied from a solvent cylinder 1 or a solvent storage tank 13, introduced into the system by a pump 2, pressurized, temperature-controlled by a heat exchanger 3, mixed with the water, and introduced into an extraction tank 4. . Further, if necessary, an excess moisture removal column 7 and/or an excess moisture removal tank 8 filled with a backing may be installed downstream of the heat exchanger 3.

The extraction tank 4 is filled with raw rice grains in advance, and comes into contact with a solvent in the presence of water to dissolve and extract soluble components (oils and fats, etc.). Next, the pressure is regulated with a pressure regulating valve, the temperature is regulated with a heat exchanger 10, and then the water is introduced into a separation tank 11. After the extract and the solvent are separated here, the pressure of the solvent is regulated using a pressure regulating valve as necessary, and then sent to the vent if not used for circulation.
After being liquefied, it is introduced into the solvent storage tank 13.

FIG. 2 shows a flow diagram of an apparatus employed when adding water to the solvent without using a pump, but using a water reservoir previously provided in the system. The solvent is supplied from a solvent cylinder 1 or a solvent storage tank 13, introduced into the system by a pump 2, pressurized, and then temperature-controlled by a heat exchanger 3 to bring it into a supercritical state or a liquid state. Next, it is introduced into a water storage tank 9 whose temperature is controlled so as not to change the temperature conditions, and after being mixed with water, it is introduced into an extraction tank 4. In addition, if necessary, the surplus water removal column 7 filled with a backing is installed in the water storage tank 9.
It may be installed on the downstream side. Thereafter, extraction and separation operations are performed in the same manner as described above.

FIG. 3, similar to FIG. 2, shows a flow diagram of an apparatus employed when adding water to the solvent without using a pump, but using a water storage tank previously provided in the system. A mixed solvent of carbon dioxide and at least one hydrocarbon among linear hydrocarbons having 2 to 4 carbon atoms is introduced into the system by pumps 2 and 14, respectively, or the mixing ratio of both is adjusted by the pump. The flow rate is measured and controlled by a flow meter installed downstream.

Carbon dioxide and hydrocarbons supplied and pressurized by a pump are mixed in the system, heated by a heat exchanger 3, and introduced into a temperature-controlled water storage tank 9, where they come into contact with water, take in moisture, and extract it. It is led to tank 4. Note that, if necessary, an excess water removal column 7 filled with a backing may be installed downstream of the water storage tank 9.

After that, extraction and separation operations are performed in the same manner as above, but after separating the extract and the solvent, the solvent is passed through a pressure regulating valve as necessary, and the total flow rate is checked with a flow meter, and then the pent line guided by.

〔Example〕

The present invention will be explained in detail below using Examples.

Example 1 Using the apparatus shown in FIG.
Year 0 production, Ibaraki Koshihikari polished rice, fat content 1.2%,
After filling 2 kg (moisture 13.5%), carbon dioxide was introduced into the system and pressurized to 200 kg/al-G using pump 2.
Furthermore, the temperature was raised to 40°C in heat exchanger 3. Moisture was fed from the storage tank 5, and was pressurized and introduced into the system by the pump 6. The amount of water added is 0.3% of the amount of carbon dioxide (
W/W). Of the added water, water with a saturation solubility or higher was removed by an excess water removal tank 8.

Carbon dioxide in a supercritical state that has taken in water from the saturated dissolution fraction is led to the extraction tank 4, brought into contact with the raw materials, and after extracting soluble components (oils and fats, etc.), 55 kg / a
After the pressure was reduced to 1-G, the mixture exited the heat exchanger 10, the temperature was adjusted to 30°C, and the mixture was introduced into the separation tank 11. The extract was separated from the solvent in the separation tank, and was extracted from the system over time through a valve at the bottom of the tank. On the other hand, the gas extracted from the upper part of the tank was depressurized by a pressure regulating valve, cooled and liquefied by a cooler 12, and then stored in a storage tank 13 for circulation. In addition, the amount of carbon dioxide circulation is 12
kg/hr, and the total amount of carbon dioxide used was 12 kg. The evaluation results of the obtained treated rice grains are shown in Tables 1 and 2.

Example 2 Using the apparatus shown in Fig. 2, 2 kg of Chiba Koshihikari brown rice produced in 1985 (lipid content 2.8%, moisture 14.8%) in Example 1 was used as the raw material, and pressurized and The heated solvent was introduced into the water storage tank 9 and bubbled to take in moisture, and the extraction pressure was 500 kg/ad-G, the extraction temperature was 50°C, the separation pressure was 60 kg/al-G, and the separation temperature was 40°C, and carbon dioxide circulation was carried out. The same procedure was carried out except that the amount of carbon dioxide used was 20 kg/hr and the total amount of carbon dioxide used was 60 kg. The evaluation results of the processed rice obtained are shown in Tables 1 and 2.
Shown in the table.

Comparative Example 1 Using the apparatus shown in FIG.
The same procedure was followed except that t% was added and the treated rice grains taken out from extraction tank 4 were left overnight in a fume hood to remove ethanol. The evaluation results of the obtained treated rice grains are shown in Tables 1 and 2.

Comparative Example 2 Using the apparatus shown in FIG. 2, the same procedure as in Example 2 was carried out except that no water was added. The evaluation results of the obtained treated rice grains are shown in Tables 1 and 2.

Comparative Example 3 Using the apparatus shown in Figure 2, the raw material used in Example 2 was wetted by uniformly spraying water in advance (the amount of water used was 5% of the weight of the raw material), and then placed in an extraction tank. After filling and processing, the rice grains are dried in a hot air dryer to maintain the same moisture content as the raw material.
The same procedure was performed except that the concentration was 8%. The evaluation results of the obtained treated rice grains are shown in Tables 1 and 2.

Table 1 Lipid content and water content NeO3 Good, △ Slightly poor Poor Example 3 Using the apparatus shown in Figure 3, the raw material was Chiba Koshihikari brown rice produced in 1985 (lipid content 2%, water content 14.
8%) 2 kg was used and treated under the following conditions.

Mixed solvent dicarbon dioxide decaethane (Mixing ratio 80:20) Extraction pressure crab 300kg/ci・G Extraction temperature: 50°C Separation pressure crab 30kg/ad・G Separation temperature = 40°C Mixed solvent circulation amount: 20 kg/hr Total amount of mixed solvent used: 60kg The evaluation results of the treated rice grains are shown in Table 3.

Example 4 Using the apparatus shown in Figure 3, the raw material was Chiba Koshihikari brown rice produced in 1985 (lipid content 2%, water content 14%).
．． 8%) 2 kg was used and treated under the following conditions.

Mixed solvent dicarbon dioxide + ethane (mixing ratio 50:50) Extraction pressure crab 200kg/cnf ・G extraction temperature: 50
°C Separation pressure = 30 kg/crl・G Separation temperature: 40°C Mixed solvent circulation amount: 20 kg/hr Total mixed solvent usage amount: 30 kg Table 3 shows the evaluation results of the treated rice grains.

Example 5 Using the apparatus shown in Figure 3, the raw material was Chiba Koshihikari brown rice produced in 1985 (lipid content 2.8%, water content 1).
4.8%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide + propane (mixing ratio 90:10) Extraction pressure crab 250kg/cIIr-G extraction temperature: 50
°C Separation pressure: 30 kg/cnf・G Separation temperature: 4・0°C Mixed solvent circulation rate: 20 kg/hr Total mixed solvent usage: 60 kg Table 3 shows the evaluation results for the treated rice grains.

Example 6 Using the apparatus shown in Figure 3, the raw material was Chiba Koshihikari brown rice produced in 1985 (lipid content 2.8%, water content 1).
4.8%) was used and treated under the following conditions.

Mixed solvent 2 carbon dioxide 10 propane (Mixing ratio 50:50) Extraction pressure crab 150kg/af G Extraction temperature: 50°C Separation pressure crab 30kg/al-G Separation temperature = 40℃ Mixed solvent circulation amount: 20 kg/hr Total amount of mixed solvent used: 30kg The evaluation results of the treated rice grains are shown in Table 3.

Example 7 Using the equipment shown in Figure 3, the raw material was Chiba Koshihikari brown rice produced in 1985 (lipid content 2.8%, water content 1).
4.8%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide decabutane (Mixing ratio 90:10) Extraction pressure crab 250kg/cof-G Extraction temperature: 50°C Separation pressure crab 30 kg/car・G Separation temperature: 40°C Mixed solvent circulation amount: 20 kg/hr Total amount of mixed solvent used: 60kg The evaluation results of the treated rice grains are shown in Table 3.

Example 8 Using the apparatus shown in Figure 3, the raw material was Chiba Koshihikari brown rice produced in 1985 (lipid content 2.8%, water content 1).
4.8%) was used and treated under the following conditions.

Mixed solvent: carbon dioxide butane (Mixing ratio 50:50) Extraction pressure crab 150 kg/ci・G Extraction temperature = 50°C Separation pressure crab 30kg/al-G Separation temperature = 40°C Mixed solvent circulation amount: 20 kg/hr Total amount of mixed solvent used: 30kg The evaluation results of the treated rice grains are shown in Table 3.

Example 9 Using the apparatus shown in Figure 3, the raw material was Ibaraki Koshihikari polished rice produced in 1985 (lipid content 1%, water content 1%).
3.5%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide + ethane (Mixing ratio 80:20) Extraction pressure = 100kg/d-G Extraction temperature: 40°C Separation pressure crab 30kg/crl-G Separation temperature = 30°C Mixed solvent circulation amount: 12kg/hr Total amount of mixed solvent used: 12kg The evaluation results of the treated rice grains are shown in Table 3.

Example 10 Using the equipment shown in Figure 3, the raw material was Ibaraki Koshihikari polished rice produced in 1985 (lipid content 1%, water content 13%).
．． 5%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide ethane (Mixing ratio 50:50) Extraction pressure = 80kg/d-G Extraction temperature: 40°C Separation pressure crab 30kg/c&・G Separation temperature: 30°C Mixed solvent circulation amount: 12kg/hr Total amount of mixed solvent used: 6kg The evaluation results of the treated rice grains are shown in Table 3.

Example 11 Using the apparatus shown in Fig. 3, the raw material was Ibaraki Koshihikari polished rice (produced in 1985) (lipid content 1%, water content 1%).
3.5%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide + propane (Mixing ratio 90:10) Extraction pressure crab l OOkg/cd-G Extraction temperature 40°C Separation pressure crab 30kg/cJl-G Separation temperature: 30°C Mixed solvent circulation amount: 12kg/hr Total amount of mixed solvent used: 12kg The evaluation results of the treated rice grains are shown in Table 3.

Example 12 Using the apparatus shown in Figure 3, the raw material was Ibaraki Koshihikari polished rice produced in 1985 (lipid content 1%, water content 1%).
3.5%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide propane (Mixing ratio 50:50) Extraction pressure crab 80kg/alf-G Extraction temperature = 40°C Separation pressure crab 30 kg/cnf-G Separation temperature: 30°C Mixed solvent circulation amount: 12 kg/hr Total amount of mixed solvent used: 6kg The evaluation results of the treated rice grains are shown in Table 3.

Example I3 Using the apparatus shown in Fig. 3, the raw material was Ibaraki Koshihikari polished rice produced in 1985 (lipid content 1).

%, moisture 13.5%) was used and treated under the following conditions.

Mixed solvent dicarbon dioxide decabutane (Mixing ratio 90:10) Extraction pressure crab 100kg/al-G Extraction temperature = 40°C Separation pressure crab 30kg/ci・G Separation temperature: 30℃ Mixed solvent circulation amount: 12kg/hr Total amount of mixed solvent used: 12kg The evaluation results of the treated rice grains are shown in Table 3.

Example 14 Using the apparatus shown in Fig. 3, the raw material was Ibaraki Koshihikari polished rice produced in 1985 (lipid content 1).

%, moisture 13.5%) was used and treated under the following conditions.

Mixed solvent: carbon dioxide + butane (Mixing ratio 50:50) Extraction pressure crab 80 kg/cd・G Extraction temperature, 40°C Separation pressure crab 30kg/cor・G Separation temperature: 30°C Mixed solvent circulation amount: 12kg/hr Total amount of mixed solvent used: 6kg The evaluation results of the treated rice grains are shown in Table 3.

Table 3 Moisture Content and Lipid Content Before and After Treatment A rice cooking test was conducted on the treated rice grains obtained in Examples 3 to 14 above, and the results showed that both appearance and aroma were good.

Good results were obtained in all items of taste (9) texture and overall evaluation.

〔Effect of the invention〕

According to the present invention, rice grains can be efficiently defatted, deodorized, etc. and modified without impairing the aroma and flavor originally present in rice grains.

[Brief explanation of drawings]

1-3 show flow diagrams of the apparatus used in carrying out the present invention. 1.1: Solvent cylinder, 2: Pump, 3: Heat exchanger, 4:
Extraction tank, 5: Storage tank, 6: Boost pump. 7: Excess water removal column, 8: Excess water removal tank. 9: water storage tank, lO: heat exchanger, 11: separation tank. 12: Cooler, 13: Solvent storage tank Patent applicant: Idemitsu Petrochemical Co., Ltd. - 109. Agent: Patent attorney Kubo 1) Fujibe +M',;□I,'
flat.

Claims (2)

[Claims] (1) When rice grains are treated with carbon dioxide in a supercritical state or liquid state to be modified, water is present in the carbon dioxide in an amount equal to or less than the saturated solubility corresponding to the state of the carbon dioxide. A method for improving rice grains characterized by: (2) When rice grains are treated with a mixed solvent of supercritical or liquid carbon dioxide and at least one hydrocarbon among linear hydrocarbons having 2 to 4 carbon atoms, the mixture 1. A method for modifying rice, which comprises treating the mixed solvent with water in an amount equal to or less than the saturation solubility depending on the state of the solvent.