JP2009011198A - Method for treatment of rice - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology that fundamentally reconsiders an ethanol production system by a conventional process (liquid fermentation process), in which the difficulties in treatment and disposal of distillery effluent in efficiently using surplus rice are big problems, and which suppresses discharging of distillery effluent, as much as possible. <P>SOLUTION: The method for treatment of rice includes processes of saccharification for saccharifying raw material rice to prepare a saccharified solution, fermentation of solids for adjusting the water content of fermentation broth, consisting of the saccharified solution, yeast and water, at the start of fermentation to 50-60 wt.% and carrying out solid fermentation and distillation process for distilling the ethanol obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a useful substance by fermentation using rice as a raw material, and more particularly, to a method for treating rice without producing a waste liquid in the production process of the useful substance.

  Currently, the minimum import obligation (minimum access = MA) rice stock, which the Japanese government is obliged to import based on the agricultural agreement of the 1993 Multilateral Trade Negotiation (Uruguay Round), is increasing. In addition, the annual total demand for domestic rice turned to a decrease after peaking at 13.41 million tons in 1963 and reached 862.9 million tons, which is 64% of the peak in FY2003. Furthermore, the annual supply per capita has been on a declining trend, peaking at 118.3 kg in 1957, and in FY2003, it was 61.9 kg, 52% of the peak, and rice continues to be surplus.

  It takes 12,000 yen per ton of rice to store these, and the storage fee alone will reach several 10 billion yen per year. In this way, in addition to the expansion of storage costs for both MA rice and domestic rice, there are many old rices that are no longer suitable for food, and the financial burden associated with their processing has become a major problem, so there is a need for effective use of surplus rice. It has been.

There is a method of converting surplus rice into energy. In particular, bioethanol produced by the ethanol fermentation method uses bioethanol from the viewpoint of reducing greenhouse gases and escaping from dependence on fossil fuels. And applications are expected to increase (Non-Patent Documents 1 and 2).
Takashi Saiki: New trends and issues related to biomass liquid fuel 1 World Biomass Conference 2004 and trends in bio liquid fuel, Bioscience and Industry, Vol. 63, No. 3, pp 182-185 (2005) Nobuo Takeda: New development of waste treatment Resource and environmental problems and development of waste treatment, Journal of the Japan Institute of Energy, Vol. 78, No. 9, pp 706-711 (1999)

  Since the conventional ethanol fermentation method using biomass as the raw material is liquid fermentation, the distillation residue remaining after ethanol is recovered from the liquid fermentation mash and the distillation waste liquid with high COD concentration are discharged, and these are treated and disposed of. I have a hard time. Currently, ethanol distillation wastewater is treated by the oxidation pond method, activated sludge method, etc., but it has been pointed out that equipment costs and operation management costs for wastewater treatment are required.

  Therefore, the present invention has fundamentally reviewed the ethanol production system based on the conventional method (liquid fermentation method), which is difficult to treat and dispose of the distillation waste liquid in order to effectively use surplus rice. It aims at providing the technique which makes it possible to suppress discharge | emission of waste liquid as much as possible.

  In order to solve the above-described problems, the present invention provides (1) a saccharification step in which raw rice is saccharified to prepare a saccharified solution, and a moisture content at the start of fermentation of the fermentation mash composed of the saccharified solution, yeast and water. The processing method of the rice which has the solid fermentation process which adjusts to 50 to 60 weight% and performs solid fermentation, and the distillation process which distills the obtained ethanol is provided.

Preferred embodiments of the invention are as follows. (2) The method for treating rice according to (1) above, wherein at least one selected from the group consisting of glutinous rice, brown rice, germinated rice, and white rice is used as the raw rice.
(3) The method for treating rice according to (1) or (2), wherein the saccharification is performed after pulverizing the raw rice.
(4) The method for treating rice according to (3) above, wherein the raw material rice uses 70% by weight or more of the pulverized particles having a particle diameter of less than 5 mm;
(5) The method for treating rice according to (3) or (4) above, wherein the raw material rice uses 50% by weight or more of the pulverized particles having a particle diameter of less than 1 mm;
(6) The method for treating rice according to any one of (1) to (5), wherein the saccharified solution is prepared by adding water and an enzyme agent to the raw rice.
(7) The method for treating rice according to (6), wherein the enzyme agent comprises α-amylase and glucoamylase;
(8) The method for treating rice according to any one of (1) to (7), further comprising a step of further distilling the obtained ethanol after the distillation step;
(9) The method for treating rice according to any one of (1) to (8), wherein the distillation step is performed at a cooling water temperature of 30 ° C. or lower.
(10) The method for treating rice according to (8) or (9) above, wherein the residue produced in the distillation step is used as fermentation mash for the next solid fermentation.

  According to the rice processing method of the present invention, ethanol can be produced using a solid fermentation method using rice as a fermentation raw material, and therefore, effective use of surplus rice such as MA rice and old rice can be achieved. The rice does not require steaming to gelatinize starch, and saccharification and fermentation are possible even with non-cooked rice, so that the steaming step can be omitted. Further, since alcohol fermentation is performed by a solid fermentation method having a relatively low water content, there is no generation of waste liquid that has been a problem in alcohol recovery, and work and costs for waste liquid treatment are unnecessary. Moreover, since the residue after distillation contains abundant nutrients derived from rice or yeast, it can be used as compost or livestock feed.

  Next, an embodiment of the present invention will be described. FIG. 1 is a diagram for explaining an outline of a rice processing method according to an embodiment of the present invention.

  As the raw material rice 1, one or more kinds selected from the group consisting of glutinous rice, brown rice, embryo rice (germ polished rice), white rice (milled rice, polished rice), waste rice, and rice bran are used.

  Here, “sticky rice” refers to seeds that have been threshed from harvested rice ears. “Brown rice” refers to the one after the rice husk has been removed from the rice. The “germ rice (germ-milled rice)” means the one that has been polished so that only the cocoon layer of the brown rice is removed and the germ remains. “White rice (milled rice, polished rice)” means a product obtained by removing the straw layer and the germ from the brown rice. “Scrap rice” refers to low-grade rice (blue rice) that has been distributed in the rice bran-rice selection process, or a powdery portion that is generated after white rice is scraped off in the milling process. The “rice cake” refers to the powder of the rice cake layer and the germ that is produced when the brown rice is polished into white rice, and there are “red rice cake” with a high proportion of rice cake layer and “white rice cake” with a high proportion of white rice.

  Among these, sticky rice is preferable because it contains a lot of proteins, vitamins and minerals on the surface, and promotes the growth of yeast and the rate of alcohol fermentation. In addition, rice husk may be added to the raw rice 1 for the purpose of adding the nutritional components contained in the sticky rice to the other raw rice 1. In addition, the raw material rice 1 used for this embodiment does not need the steaming process for gelatinizing starch, and can be used as it is without steaming.

  The raw material rice 1 is pulverized (S2). Although the pulverization process is not essential, it is preferable to pulverize the raw rice because the saccharification in the saccharification step can be efficiently performed as compared with the case where the pulverization process is not performed.

  From the viewpoint of increasing the efficiency of saccharification, it is preferable that 70% by weight or more of the pulverized rice powder 2 (particles) has a particle diameter of less than 5 mm. In particular, it is particularly preferable that 50% by weight or more of the pulverized rice powder 2 (particles) has a particle diameter of less than 1.0 mm because saccharification is performed more efficiently.

  The particle diameter of the rice powder 2 here is determined by whether or not it passes through a sieve made of a mesh having a predetermined opening. For example, “particle diameter of less than 5 mm” passes through a four-sided mesh having an opening of 5 mm. The term “particle diameter less than 1 mm” means that which passes through a four-sided mesh with an opening of 1 mm. In the present invention, it is particularly desirable to pulverize the raw rice 1 so that the amount of particles passing through a four-sided mesh having a particle diameter of 1 mm of the rice powder 2 (ie, particles having a particle diameter of less than 1 mm) is 50% by weight or more. .

  The rice powder 2 is saccharified by adding the enzyme agent 3 and water 10 (S2). The enzyme agent 3 can be used without particular limitation as long as it is an amylase-based enzyme, but an enzyme agent containing α-amylase and glucoamylase is preferable because of its excellent saccharification efficiency. As the enzyme agent 3, a commercially available enzyme agent can be used, and examples thereof include Kokugen G20 (α-amylase 1%, glucoamylase 80% and dextrin 19%) manufactured by Daiwa Kasei Co., Ltd.

  Although the addition amount of the enzyme agent 3 can be determined arbitrarily, from the viewpoint of saccharification efficiency, it is about 0.1 to 0.3% by weight with respect to the weight of the raw rice 1 or rice powder 2.

  As the water 10, it is preferable to use pure water or ultrapure water such as ion exchange water, ultrafiltration water, reverse osmosis water, or distilled water. In particular, water obtained by sterilizing these waters by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria is prevented.

  The amount of water 10 added is preferably 40 to 60% by weight based on the weight of the raw rice 1 or rice powder 2. By adjusting the amount of water added to 40 to 60% by weight, fermentation with low moisture is possible, so that the treatment of the distillation waste liquid becomes unnecessary.

  In the saccharification treatment (S2), koji molds may be added instead of adding the enzyme agent 3. As the koji mold, for example, Aspergillus sojae KBN606 (for soy sauce), Aspergillus sojae KBN615 (for soy sauce), Aspergillus oryzae KBN650 (for soy sauce), Aspergillus oryzae KBN930 (for miso), Aspergillus oryzae KBN943 (for barley miso), Aspergillus 15 oryzae KB (For sake), Aspergillus kawachii KBN2001 (for shochu), Aspergillus kawachii P10-1 (for shochu), Aspergillus awamori KBN2012 (for shochu), Aspergillus saitoi KBN2024 (for Awamori), etc., especially Aspergillus kawachii KBN2001 ( It is preferable to use Aspergillus kawachii P10-1, A. oryzae KBN1015, A. oryzae KBN943. In addition, when saccharification is performed using koji mold, it is not necessary to add water 10 in the saccharification treatment (S2) step.

  Next, yeast 5 and, if necessary, water 10 are added to the obtained saccharified solution 4 to prepare fermentation mash 6. At this time, the fermentation moromi 6 is adjusted to a water content of 50 to 60% by weight at the start of fermentation, and solid fermentation is performed (S3).

  Here, solid fermentation refers to a fermentation method that is performed in a solid state from the start to the end of fermentation using fermentation mash that maintains the minimum amount of water that allows yeast growth and ethanol fermentation.

  In the conventional liquid fermentation method, yeast is added to an aqueous solution containing about 5 to 10% by weight of reducing sugar and cultured, and when alcohol is recovered by distillation after the alcohol fermentation is finished, a waste liquid and a fermentation residue are generated. On the other hand, in the solid fermentation method, only the fermentation residue is produced after ethanol is recovered by distillation, so there is no generation of waste liquid, and work and costs for waste liquid treatment become unnecessary. Moreover, since the water content is lower than that of the liquid fermentation method, the generation of malodor is small and the ethanol can be easily recovered.

  When rice is used as a raw material as in the present invention, almost no alcohol is produced when the water content at the start of fermentation is less than 50% by weight, whereas when the water content exceeds 60% by weight, alcohol is recovered. Since waste liquid is generated, it is not preferable.

  The saccharification step (S2) and the solid fermentation step (S3) can be performed separately, but can be performed simultaneously by the so-called parallel multi-fermentation format. In such a case, the raw material rice 1 or rice powder 2, the enzyme agent 3, the yeast 5 and the water 10 may be added simultaneously.

  The temperature of the solid fermentation can be appropriately set depending on the optimum temperature of the yeast 5, but it is preferable to set the temperature at a temperature of 20 to 25 ° C. because it is economical in terms of cost.

  As the yeast 5, yeast of the genus Saccharomyces serevisiae generally used for alcohol fermentation can be used. A part of the moromi after the fermentation can be used as an inoculum (starter) for the next fermentation. The alcohol concentration at the end of fermentation is about 12% by weight.

  After completion of the solid fermentation, a distillation step of distilling the obtained ethanol is performed as necessary (S4). In the distillation step, the fermentation mash 6 is distilled by a distillation apparatus or the like, and the ethanol concentration is concentrated to about 60% by weight or more. Thereby, crude distillation ethanol 7 is obtained.

  The distillation step is preferably carried out under conditions where the cooling water temperature is 30 ° C. or lower. The lower the temperature of the cooling water, the higher the efficiency of liquefying the vaporized ethanol.

  Furthermore, it is preferable that after the distillation step (S4), a step of further distilling the obtained crude distillation ethanol 7, that is, a rectification step (S5) is performed as necessary. A general rectification apparatus etc. can be used for a rectification process (S5). In the rectification step (S5), the ethanol concentration is finally concentrated to about 90% by weight or more. Thereby, rectified ethanol 8 is obtained.

  The obtained ethanol (crude ethanol 7 or rectified ethanol 8) can be used in various fields such as industrial alcohol and brewing alcohol.

  The distillation residue 9 produced as a by-product in the distillation step (S4) contains abundant nutrients derived from the raw rice 1 and yeast 5, and is nutritionally superior. Therefore, feed and fertilizer (S6) are implemented. Therefore, it can be effectively used as feed for livestock and fertilizer for agricultural crops.

  When distilling residue 9 is used as feed for livestock, for example, distilling residue 9 can be supplied to livestock as it is or after drying treatment. Moreover, when making the distillation residue 9 into fertilizer, a fertilizer useful for a crop is obtained by adding a carbon source or a nitrogen source as needed, and adjusting C / N ratio suitably, for example.

  In addition, the distillation residue 9 can also be reused as fermentation mash of the next solid fermentation (S3). That is, by carrying out distillation, saccharification of fermentation moromi proceeds by heating, and the amount of reducing sugar after distillation increases by 1 to 3% from the amount of reducing sugar before distillation. Therefore, part or all of the distillation residue 9 is transferred to the next solid fermentation step, and the yeast 5 and the water 10 are added, so that the solid fermentation can be performed again as the fermentation mash 6. Since the raw material is starch, re-fermentation of the distillation residue 9 can be performed a plurality of times.

  In the rectification step (S5), some waste water 20 is also produced, but BOD and COD are extremely low and can be reused for various purposes.

  Next, a rice processing system for carrying out the rice processing method of the above embodiment will be described with reference to FIGS. 1 and 6.

  FIG. 6 is a diagram for explaining the outline of the rice processing system of the present embodiment. As shown in FIG. 6, the rice processing system of the present embodiment includes a pulverizer 30 that crushes raw rice 1, a fermenter 40 that performs saccharification and solid fermentation, and a distiller 50 that performs ethanol distillation. Has been.

  First, a predetermined amount of raw rice 1 is introduced into the crusher 30 from the inlet and crushed. Crushed raw rice (hereinafter referred to as rice powder 2) is discharged from the discharge port of the crusher 30, and the container 32 receives this. In addition, the crusher 30 is preferably pulverized such that particles passing through a 1 mm square mesh of raw uncooked rice are 50% by weight or more, and a crusher such as a crushing type secondary crusher is preferable. .

  Next, the rice powder 2 is put into the fermenter 40 from the container 32. In the fermenter 40, a vertical stirring means 42 for stirring the rice powder 2 is provided. The stirring means 42 is provided in the fermenter 40 so as to extend in the longitudinal direction of the fermenter 40 so as to extend in the longitudinal direction, and on the outer periphery of the rotational shaft 44 so as to extend outward in the radial direction. The plurality of stirring blades 46 and a drive motor 48 that rotationally drives the rotary shaft 44 are roughly configured.

  After the rice powder 2 is put into the fermenter 40, the enzyme agent 3 and the yeast 5 are subsequently added, and further water 10 is added so that the water content of the fermented mash is 60% by weight, followed by saccharification and solids. Fermentation (parallel double fermentation) is performed. During saccharification and fermentation, during the saccharification and fermentation time set in advance, the drive motor 48 and the suction pump are started at predetermined intervals, and the fermentation mash 6 in the fermenter 40 is periodically agitated and aspirated to saccharify. Perform the process and fermentation process. In addition, since internal temperature rises with the heat | fever which generate | occur | produces in a fermentation process, it is necessary to adjust to the optimal temperature for fermentation through an appropriate temperature heating medium to a jacket. In addition to water vapor, the gas generated during the fermentation process includes carbon dioxide gas or alcohol vapor, which is a fermentation product.

  After completion of the solid fermentation, the fermentation mash 6 is taken out from the bottom or side of the fermenter 40 and transferred to the distiller 50. The distiller 50 is preferably a distiller such as a vacuum distiller. Distilled ethanol 7 having a desired concentration is obtained by distillation.

1 Ethanol production method (1) Raw rice As raw rice, five types of surplus rice, glutinous rice, brown rice and polished rice, glutinous rice and brown rice cultivated in Iwate Pref. It was. These raw rices were each pulverized using a KYB crushing type secondary pulverizer Town Beaver Mill. FIG. 2 is a diagram showing the particle size distribution of the powder after pulverizing the broken rice. As shown in FIG. 2, the particle diameter was the largest when the particle diameter was less than 1 mm. In addition, it grind | pulverized so that it might become the same particle size distribution about other raw material rice.

  Moreover, the above-mentioned crushed rice was not subjected to the pulverization process, and the raw rice having a particle diameter of about 5 mm (referred to as “granular rice” in FIG. 5) was used as it was. Further, as a comparative example, a case where potato was used instead of the raw rice and pulverized as described above was used as the raw material.

(2) Test enzyme agent As an enzyme agent, Kokugen G20 (α-amylase 1%, glucoamylase 80%, dextrin 19%) manufactured by Daiwa Kasei Co., Ltd. was used, and 0.25 relative to the total weight of the raw rice. % Weight was added.

(3) Test yeast The yeast is a shochu yeast A30 Saccharomyces, a gift from the Department of Brewing Microbiology, Tokyo University of Agriculture.
cerevisiae was used. 10 ml of YM medium consisting of 0.5% by weight of polypeptone, 0.3% by weight of yeast extract, 2.0% by weight of glucose, and 0.3% by weight of maltose was dispensed into an L-shaped tube, and autoclaved (1.2 atm, 121 After 20 minutes of incubation at 20 ° C., 1 platinum ear of the shochu yeast was inoculated under aseptic conditions and subjected to shaking culture (25 ° C., 48 hours).

(4) Saccharification and solid fermentation About 10 kg of each of the rice powders crushed as described above was placed in a fermenter, and water was added so that the water content of the fermented mash was 60 wt%. Next, 4 L of precultured yeast and Kokugen G20 were added to the fermentor, and saccharification and solid fermentation were performed at room temperature for 3 days. In addition, it carried out also about the case where the moisture content of fermentation mash was adjusted to 40 weight%, 50 weight%, and 70 weight%, respectively.

(5) Distillation and distillation apparatus Distillation was performed after completion of solid fermentation. Distillation of the solid fermented product is carried out by putting the solid fermented product after fermentation into a vacuum distillation apparatus (inner diameter 600 mm x height 210 mm, dome shape with an effective volume of about 40 L) and setting the internal pressure to -0.09 Mpa with a vacuum pump. Then, the temperature of the cooling water in the tank was reduced to 30 ° C. or lower, and vacuum distillation was performed for about 2 hours. By distillation, ethanol having an ethanol concentration of 92% by weight was obtained. In addition, a part of the residue generated by distillation was added to the fermentation mash, and the rest was fertilized.

2 Test Example (1) Measurement of Total Sugar Total sugar was measured using raw rice as a test sample as a sample. The total sugar was measured by the phenol sulfuric acid method. A sample was taken in a 5 g sample bottle, charged with 20 ml of ultrapure water and 5 ml of 25% hydrochloric acid, sealed and boiled for 2.5 hours. After 2.5 hours, it was cooled, neutralized, filtered and quantified using a 100 ml volumetric flask. A solution obtained by further diluting the filtrate 5000 times was used as a sample for analysis.

  In a test tube, 1 ml of a sample diluted 5000 times with total sugar was mixed with 1 ml of 5% phenol solution and 5 ml of concentrated sulfuric acid, allowed to stand for 15 minutes, and the absorbance at 490 nm was measured.

  The standard curve is prepared by diluting 0.1 g of glucose in a 1 L volumetric flask and adjusting the diluted solution to 100% with 0%, 20%, 40%, 60%, 80%, 100% and ultrapure water. Then, the absorbance at 490 nm was measured by the phenol sulfuric acid method. The results are shown in FIG.

  As shown in FIG. 3, the sugar content of raw rice with rice husk (with Hitomebori rice) and brown rice (Hitomebo rice) is 32.6% by weight for raw rice with rice husk and 33.1% by weight for brown rice. It was almost the same amount. The raw rice used for solid fermentation is about 10 kg each, but the raw rice with rice husk contains rice cake in 10 kg, so it can be said that the raw rice with rice husk actually has less sugar than brown rice. Nevertheless, the same amount of sugar as brown rice was confirmed by subtracting the amount of rice bran, so it was considered that raw rice with rice husk had higher saccharification efficiency than brown rice.

(2) Measurement of the number of yeasts The number of yeasts was measured with a Thomas hemacytometer. 1 g of mash after solid fermentation was collected in a test tube with a lid, and diluted 10-fold with ultrapure water was dropped between a hemocytometer and a cover glass with a pipette. Then, after 1-2 minutes, the sample was examined, and the number of yeast in 1 ml was calculated according to the following formula. The results are shown in FIG.

Number of yeast in 1 ml = 4a × 10 ⁶ × dilution ratio (a: total average number of yeasts in 1 section (0.00025 mm ³ ))

  As shown in FIG. 4, it was found that raw rice with rice husk (with Hitomebori rice) has more yeast than brown rice (Hitomebori brown rice). As the number of yeasts increases, the fermentation rate increases in proportion. From this, it was inferred that ethanol can be produced more efficiently by using raw rice with rice husks, that is, rice bran.

(3) Measurement of ethanol production amount 3 g of moromi after solid fermentation was collected in a test tube with a lid, and diluted with 2 ml of ultrapure water. The supernatant liquid after centrifugation by tabletop centrifugation (SPEED3, 10 min, x1000 rpm) was filtered through a 0.45 μm coma filter. The filtrate was measured with an alcohol concentration meter manufactured by YAZAKI. The results are shown in FIG.

  As shown in FIG. 5, when the amount of ethanol produced by the raw rice was compared, the amount of ethanol produced by rice husk with rice husk was about 2% higher than that of brown rice. Focusing only on the amount of ethanol produced, the difference between using raw rice with rice husks and using brown rice is small. However, in consideration of the measurement result of the total sugar amount (FIG. 3), it is considered that the ratio of the sugar amount is higher when the raw rice with rice husk is used than the brown rice, and the measurement result of the number of yeasts (FIG. 4). Therefore, the number of yeasts is larger when using raw rice with rice husk than brown rice. Therefore, it was suggested that ethanol can be produced more efficiently by using raw rice with rice husks.

(4) Examination of water content Table 1 shows the result of comparing the ethanol production efficiency by the difference in water content at the start of solid state fermentation. The ethanol production efficiency ([B / (A * 0.51)]) is determined by measuring the total sugar consumption and the ethanol production, and converting the ethanol production (B) into the total sugar consumption (A) and the ethanol conversion coefficient (0). This was done by comparing the value divided by the product of .51). As a result, when the fermentation is carried out using the fermentation mash whose water content at the start of solid fermentation is adjusted to 50% by weight, and the fermentation mash that is adjusted to 60% by weight, the fermentation mash at the start of solid fermentation is in progress. It was found that ethanol production was performed more efficiently than when the water content was adjusted to 40% by weight or 70% by weight.

(5) Measurement of C / N ratio In order to confirm whether the distillation residue generated after the distillation step has suitability as a fertilizer, the C / N ratio of rice powder with a glaze husk was examined. The C / N ratio was determined by measuring the carbon content (C) and nitrogen content (N) by the Dumas method and calculating from the obtained values. As a comparison, Table 2 shows the C / N ratio of rice powder before saccharification / solid fermentation (indicated as “before saccharification / solid fermentation” in Table 2).

  Generally, it is said that the C / N ratio as a fertilizer is preferably about 10. The raw rice has a high C / N ratio before saccharification and solid fermentation (that is, untreated raw rice) and cannot be said to be suitable as a fertilizer. On the other hand, it was found that the C / N of the distillation residue after saccharification / solid fermentation and distillation for obtaining ethanol showed an appropriate value as a fertilizer.

It is a figure for demonstrating the outline | summary of the processing method of the rice of this embodiment. It is a figure which shows the particle diameter distribution of the rice powder after grind | pulverizing raw material rice. It is a figure which shows the measurement result of the total sugar of raw material rice. It is a figure which shows the result of having measured the number of yeast in the mash after solid fermentation. It is a figure which shows the result of having measured the ethanol production amount in the mash after solid fermentation. It is a figure for demonstrating the outline | summary of the processing system of the rice of this embodiment.

Explanation of symbols

1: raw rice, 2: rice powder, 3: enzyme preparation, 4: saccharified solution, 5: yeast, 6: fermentation mash, 7: crude ethanol, 8: rectified ethanol, 9: distillation residue, 10: water, 20: Wastewater, 30: Crusher, 32: Container, 40: Fermenter, 42: Stirring means, 44: Rotating shaft, 46: Stirring bar, 48: Drive motor, 50: Distiller

Claims (10)

A saccharification process in which raw rice is saccharified to prepare a saccharified solution;
A solid fermentation process for solid fermentation by adjusting the water content at the start of fermentation of the fermentation moromi composed of the saccharified solution, yeast and water to 50 to 60% by weight;
A distillation step of distilling the obtained ethanol;
A method for treating rice having   The method for processing rice according to claim 1, wherein at least one selected from the group consisting of glutinous rice, brown rice, germ rice, and white rice is used as the raw rice.   The said saccharification is a processing method of the rice of Claim 1 or 2 performed after grind | pulverizing the said raw material rice.   The method for treating rice according to claim 3, wherein 70% by weight or more of the pulverized particles have a particle diameter of less than 5 mm.   The processing method of the rice of Claim 3 or Claim 4 which uses what the particle | grain diameter after grinding | pulverization 50 weight% or more of is less than 1 mm as said raw material rice.   The said saccharified liquid is a processing method of the rice of any one of Claims 1-5 prepared by adding water and an enzyme agent to the said raw material rice.   The method for treating rice according to claim 6, wherein the enzyme agent comprises α-amylase and glucoamylase.   The processing method of the rice of any one of Claims 1-7 which has the process of further distilling the obtained ethanol after the said distillation process.   The said distillation process is a processing method of the rice of any one of Claims 1-8 performed by the water temperature of 30 degreeC or less of cooling water.   The processing method of the rice of Claim 8 or 9 which uses the residue produced in the said distillation process as fermentation mash of the next solid fermentation.