JPH04278073A - Preparation of raw material rice for brewing and brewing thereof - Google Patents

Abstract

PURPOSE:To effectively remove lipid without eliminating a large amount of raw material rice for brewing by mechanical rice cleaning by subjecting raw material rice for brewing as it is or after any process of rice polishing, cleaning, immersing or steaming to specific extracting operation. CONSTITUTION:Raw material rice for brewing as it is or after any process of rice polishing, cleaning, immersing or steaming is brought into contact with carbon dioxide in a liquid or supercritical state and extracted so that saccharide attached to the surface of the raw material rice in rice polishing are removed and extraction efficiency of lipid is improved with carbon dioxide. The cleaning and immersing operations are preferably carried out by using water processed with an alkali or an acid and the extracting operation is done by bringing carbon dioxide in an upward countercurrent into contact with the raw material rice for brewing packed into a container.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing rice for brewing, which is a raw material for sake, and a method for brewing sake.

0002

BACKGROUND OF THE INVENTION In addition to starch, rice used as a raw material for brewing contains water, protein, lipids, and inorganic substances such as phosphorus and potassium. Among these, lipids are said to affect the production of aroma esters by sake yeast, and unsaturated fatty acids in particular are said to inhibit this production. Usually brown rice has 3 fats.
%, and most of it is present near the surface layer, so rice polishing is performed to mechanically remove the surface of brown rice. Polished raw material rice for brewing has bran attached to its surface, so it is washed, soaked, and steamed (adding heat and humidity to steam) as shown in Figure 5 (a). . The rice polishing ratio is generally 70 to 75 percent for regular sake and 35 to 60 percent for ginjo sake, and rice polishing is the cause of a significant decrease in the utilization rate of raw rice for brewing. In order to solve this problem, a method of selectively extracting and separating lipids by lowering the rice polishing ratio may be considered. The lipids near the surface layer of raw rice for brewing are free fatty acids.
It can be extracted with an organic solvent such as n-hexane. However, this method cannot be easily applied because it not only deteriorates alcohol quality due to residual solvent but also has toxicity problems. For this reason, attempts have been made to perform extraction with carbon dioxide. This method is disclosed in Japanese Patent Application Laid-Open No. 60-188053,
This system converts carbon dioxide into a liquid or supercritical state under a predetermined pressure and temperature to add the ability to extract lipids from rice, a raw material for brewing. Carbon dioxide is harmless and can be extracted and separated simply by controlling pressure and temperature, making it a suitable method for defatting rice used as a raw material for brewing. in particular,
As shown in Figure 5 (b), raw rice for brewing that has been polished to 80 to 85% is brought into contact with liquid or supercritical carbon dioxide, and the lipids in the rice for brewing are extracted from the 70% lipids used in regular sake.
Defatted to the same level as 0% polished rice. The degreased raw rice for brewing is washed to remove the bran on the surface, as in the traditional method, and then soaked and steamed to complete the preparation.

0003

[Problems to be Solved by the Invention] However, when the present inventors experimented with the extraction using carbon dioxide, it was found that the degreasing effect was small despite the large amount of carbon dioxide used. Furthermore, due to the increased rice polishing ratio,
It has been found that proteins and inorganic substances that are difficult to remove with carbon dioxide extraction tend to remain, and that these substances have a negative effect on the quality of sake after brewing. An object of the present invention is to solve the drawbacks of the prior art and to provide a preparation method that effectively removes lipids using carbon dioxide without removing a large amount of raw rice for brewing by mechanical milling. Another object of the present invention is to provide a method for preparing raw material rice for brewing that can reduce the protein and minerals remaining in the raw material rice for brewing, if necessary, and to brew sake using the prepared rice. Regarding.

0004

[Means for Solving the Problems] The present invention provides a method for preparing raw material rice for brewing in which the rice raw material for brewing after milling is processed in the order of washing, soaking, and steaming. The present invention is characterized in that after any of the operations, an extraction operation is added in which the rice raw material for brewing is brought into contact with liquid or supercritical carbon dioxide. For washing and soaking operations, either brewing water or brewing water treated with alkali or acid is used. In the extraction operation, it is preferable that carbon dioxide is brought into contact with the raw material rice for brewing filled in a container in an upward flow. It is even more preferable to crush the raw rice for brewing before the extraction operation.

[0005]

[Operation] By washing the raw material rice for brewing after milling, the bran adhering to the surface of the raw material rice for brewing during milling is removed. Since bran contains a large amount of lipids, removing the bran and then performing extraction with carbon dioxide improves the efficiency of lipid extraction. Using water treated with alkali or acid in the washing and soaking operations not only removes the bran, but also reduces proteins and inorganic substances that are difficult to remove in the subsequent extraction operations, which has a positive impact on the quality of sake after brewing. bring. In the extraction operation, the extraction effect is improved by bringing carbon dioxide into contact with the raw material rice for brewing filled in a container in an upward flow. When the raw rice for brewing is crushed before the extraction operation, the surface area per unit of the raw rice for brewing increases due to the crushing, and the extraction effect is further increased.

[0006]

EXAMPLE FIG. 1 shows an embodiment of the present invention. In contrast to the conventional method for preparing raw rice for brewing shown in Figure 5 (a), in which the raw rice for brewing after milling is processed in the order of washing, soaking, and steaming, Figure 1 (a) shows a process of washing and soaking. Figure 1 (b) shows an extraction operation added between soaking and steaming, and Figure 1 (c) shows an extraction operation added after steaming.

[0007] Compared to the conventional rice milling ratio of about 70%, in the case of the present invention, a rice polishing ratio of 80 to 90% is sufficient, and the utilization rate of raw rice for brewing can be increased accordingly. The washing and soaking operations use either brewing water or brewing water treated with alkali and acid. For example, a dilute solution of potassium carbonate is used as the alkaline water. Further, as the organic acid water, for example, lactic acid water is used, but other alkalis and acids are also effective. The steaming operation will be the same as the conventional method. The extraction operation is performed by bringing the rice raw material for brewing into contact with liquid or supercritical carbon dioxide after any of the above operations. If the extraction operation is performed before the washing operation as shown in FIG. 5(B), the bran adhering to the surface of the raw material rice for brewing will have an adverse effect and the effect will be reduced. After any one of the washing, soaking, and steaming operations, the water content of washed rice, soaked rice, and steamed rice increases, and this water content also causes a reduction in the effectiveness of extraction. However, according to the experiments of the present inventors,
It was found that the negative effects of bran were greater than those of water. It is preferable to crush the raw material rice for brewing prior to extraction. Grinding is carried out immediately before washing or extraction in the case of Fig. 1 (a), immediately before or after washing and immediately after extraction in the case of Fig. 1 (b), and immediately before or after washing in the case of Fig. 1 (c). Alternatively, it may be carried out at any time immediately after immersion. In the case of FIG. 1(c), if the pulverization is performed immediately after steaming, the raw material rice for brewing becomes pasty, which is not preferable. In addition, if pulverization is performed before soaking, the starch in the raw rice for brewing will easily flow out during soaking, so it is most preferable to mill, wash, soak, and
Adjustment is carried out in the order of crushing, extraction, and steaming, and then it is used for brewing. Preliminary Experiment Example 1 After thoroughly washing raw rice for brewing with a polishing ratio of 92%,
Samples with different moisture contents in the range of 12 to 42% were prepared, and supercritical carbon dioxide was brought into contact with the samples in an upward or downward flow.
Extraction was performed. The extraction conditions at this time are pressure 280Kg/c.
m2, and the temperature was 20°C. Note that the moisture content of raw rice for brewing is 12% when no moisture is attached to its surface.

The results of the experiment are shown in FIG. It can be seen that as the water content increases, the crude fat content in the sample after extraction increases and the extraction effect decreases. In the figure, line A shows the case where carbon dioxide flows upward, and line B shows the case where carbon dioxide flows downward. As is clear from the figure, the extraction effect is improved when carbon dioxide is contacted in an upward flow. Preliminary experiment example 2 Two cases where raw material rice for brewing with a rice polishing ratio of 85% is directly extracted without washing (conventional method), and another case where the water content is extracted by approximately 2% after thorough washing (conventional method).
A comparison was made with the case where the concentration was adjusted to 5% and then extracted (the present invention). The extraction conditions were the same as in Preliminary Experiment Example 1.

The results of the experiment are shown in FIG. In the figure, line C is for direct extraction without washing (conventional method), line D is for direct extraction without washing and then washing (conventional method), and line E is for direct extraction without washing (conventional method).
shows the case of extraction after washing (the present invention). According to the present invention, the amount of carbon dioxide used for extraction is 0.8 kg.
/kg of rice, the crude fat content of the raw material rice for brewing can be about 0.1%. This crude fat content of 0.1% is equivalent to the crude fat content when raw material rice for brewing with a milling ratio of 70 to 75% is washed. On the other hand, according to the conventional method, the amount of carbon dioxide used for extraction is 0.8 kg.
/kg of rice, the crude fat content is 0.17% even after washing, and in order to achieve the same level of 0.1% as in the method of the present invention, approximately 3kg/kg of carbon dioxide in rice is required. It becomes necessary. Preliminary Experimental Example 3 The same experiment as Preliminary Experimental Example 2 was conducted, except that the rice polishing ratio of the sample raw rice for brewing was 90%. The results are shown in FIG. In the figure, line F indicates the case of direct extraction without washing (
Line G shows the case where extraction is performed directly without washing and then washing (conventional method), and line H shows the case where extraction is performed after washing (method of the present invention). As is clear from the figure, the same tendency as Preliminary Experimental Example 2 is shown. However, even with the method according to the present invention, the crude fat content of raw rice for brewing after extraction is 0.3%.
It was found that the effect of fat was insufficient. Therefore, we conducted an additional experiment in which raw rice for brewing was washed, crushed, and then extracted. The results are shown in Figure 4, line I,
Indicated by J and K. Line I is the case when the particle size of the pulverization is 24 mesh or less, line J is the case when the particle size of the pulverization is 48 mesh or less, and line K is the case when the particle size of the pulverization is 100 mesh or less. It can be seen that by pulverizing the raw rice for brewing before extraction, the crude fat content of the raw rice for brewing after extraction can be significantly reduced, and the degree of pulverization can be set to 48 mesh or less. Comparative Experimental Example 1 Various experimental methods were used to prepare raw rice for brewing. The results are shown in Table 1. In the same table, experiments a, b, and c are shown in Figure 5 (
Experiments d and e are the conventional method shown in Figure 5 (B), and experiments f to p are the conventional method shown in Figure 1 (A), (B), and (C). The method according to the present invention is shown in FIG. The experiment was conducted using the same type of raw rice for brewing and varying the rice polishing ratio, presence or absence of pulverization, moisture content of the raw rice for brewing at the time of extraction, and amount of carbon dioxide used as shown in the table. All grinding, if any, was carried out immediately before the extraction operation. Washing was carried out using brewing water, and soaking and steaming were carried out under the same conditions in each experiment. The conditions of carbon dioxide pressure and temperature in the extraction operation were the same as in Preliminary Experimental Example 1. Further, based on the results of Preliminary Experiment Example 1, carbon dioxide was brought into contact with the raw material rice for brewing in an upward flow. In the same table, the value of the crude fat content shows the value of the raw material rice for brewing after all adjustments were completed for each experiment (steaming in experiments a to m, extraction in experiments n and p). Table 1 shows that when the present invention is implemented, the crude fat content of raw rice for brewing can be effectively reduced, and the amount of carbon dioxide required for extraction may also be small. In particular, if pulverization is performed immediately before the extraction operation, even rice with a polishing ratio of 90% can have the same crude fat content as the conventional rice with a polishing ratio of 70%, and the utilization rate of raw rice for brewing can be improved. Improve dramatically.

0010

[Table 1] Comparative Experiment Example 2 In the washing and soaking operations of the present invention, protein and iron in rice were removed using water treated with alkali and acid other than brewing water as washing water and soaking water. show. white rice 1
00g (1989, Fukui rice, milled rice 90%) was heated at 15°C, 30°C, 40°C, 50°C using lactic acid at a concentration of 5000 ppm and potassium carbonate at 2000 ppm.
After soaking for 12 hours, draining and washing with water,
Crude protein and iron in rice were measured. As a control, white rice with the same polishing ratio of 90% was washed and soaked in brewing water under the same processing conditions as above, and white rice with a polishing ratio of 73% was washed and soaked in brewing water in the same manner. The amount and iron content were compared. Table 2 shows the results. Table 2 shows that by soaking 90% polished rice in lactic acid at 50°C, the crude protein content becomes almost the same as that of 73% polished rice, and the iron content is slightly higher than that of 73% polished rice, but it decreases. I understand. Furthermore, Table 3 shows the effects of removing crude protein and iron due to differences in lactic acid concentration. From Table 3, it can be seen that the target crude protein and iron contents are achieved at lactic acid of 5000 ppm or more.

[0011]

[Table 2]

0012

[Table 3] Example 2 A sake brewing test was conducted based on the preliminary and comparative experimental examples described above. That is, rice milled to a polishing ratio of 90% was washed and soaked in a 0.5% lactic acid solution overnight. After soaking, wash and drain, crush with a crusher (Fitzmill), and reduce the pressure to 280.
Kg/cm2, temperature 20°C, carbon dioxide amount 0.8Kg/
Raw material rice for brewing was prepared by supercritical extraction using Kg rice. Using 1 kg of this rice, a brewing test was conducted after liquefying it with heat-resistant liquefying amylase. In addition, as a control, three-stage preparation was performed using steamed 73% polished rice, and liquefaction preparation was performed using soaked rice. As shown in FIG. 6, the fermentation proceeded in almost the same manner as the control, and the analysis results after the upper tank and the storage test results (Table 4) showed almost no difference from the control. In addition, the sake yield results (Table 5) by 12 panelists showed that sake with no significant difference from the control was obtained, and by using rice that had been soaked in lactic acid and treated with supercritical carbon dioxide gas, it was possible to reduce raw material costs without sacrificing quality. We have established a sake brewing method that can reduce this amount.

[0013]

[Table 4] Control 1: Brewed by liquefying soaked rice in the same way as in this method. Control 2: Brewed using rice in three stages.

[0014]

[Table 5] *Scored as 1 for the best, 2 for good, 3 for slightly poor, and 4 for the worst.

[0015]

Effects of the Invention The present invention provides a method for preparing raw material rice for brewing in which the rice raw material for brewing is processed in the order of washing, soaking, and steaming, either as it is or after milling. After any of these operations, an extraction operation was added in which the raw rice for brewing was brought into contact with liquid or supercritical carbon dioxide, so the raw rice for brewing could be removed without removing a large amount of raw rice by mechanical polishing. , lipids can be effectively removed by carbon dioxide. In addition, in the above preparation method, if water treated with alkali or acid is used for washing and soaking operations, it is possible not only to remove bran but also to reduce proteins and inorganic substances that are difficult to remove in the subsequent extraction. It has a positive effect on the quality of sake afterwards. In the extraction operation, the extraction effect is improved by bringing carbon dioxide into contact with the raw material rice for brewing filled in a container in an upward flow. When raw rice for brewing is crushed before the extraction operation, the surface area per unit amount of raw rice for brewing is increased by crushing, and the extraction effect is further increased.

[Brief explanation of the drawing]

[Fig. 1] Fig. 1 is a block system diagram showing an embodiment of the present invention.

[
Figure 2: Figure 2 is a graph showing the results of preliminary experiment example 1.

[Figure 3]
Figure 3 is a graph showing the results of preliminary experiment example 2.

[Figure 4] Figure 4 is a graph showing the results of preliminary experiment example 3.

[Figure 5] Figure 5 is a block diagram showing a conventional method for preparing raw rice for brewing.

Claims (5)

[Claims] Claim 1: The raw material rice for brewing is made into a liquid or supercritical state either as it is or after any one of the following steps of washing, soaking, and steaming after milling. A method for preparing rice as a raw material for brewing, which comprises adding an extraction operation of bringing it into contact with carbon dioxide. 2. The method for preparing raw rice for brewing according to claim 1, wherein the washing and soaking operations use either water treated with alkali or acid. 3. The method for preparing raw rice for brewing according to claim 1, wherein the extraction operation includes bringing carbon dioxide into contact with the raw rice for manufacturing filled in a container in an upward flow. 4. The method for preparing raw rice for brewing according to claim 1, characterized in that the raw rice for brewing is crushed before the extraction operation. 5. A method for brewing alcoholic beverages, characterized in that the rice obtained by the preparation method according to any one of claims 1 to 4 is used.