JP2011083196A - Method for producing quick-cooking rice and quick-cooking rice produced by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing quick-cooking rice having an excellent outer appearance without requiring a drainage facility. <P>SOLUTION: The method for producing the quick-cooking rice includes adding water to raw material rice not by a soaking method but by a quantitative moisture adding method so as to prevent superfluous water and drainage, and consequently, the method requires no drainage facility to reduce a cost of a production facility. In the producing method, a preliminary pressurized steam-boiling step is performed to form a uniform alpharized surface of rice grains, and then the quantitative moisture adding step is performed. Since the surface of the raw material rice is uniformly alpharized to become stiff without cracks with the preliminary pressurized steam-boiling process, the quantitative moisture addition does not cause a crack in the raw material rice. The shape of the rice grains is not deformed even in a subsequent alpharizing step, finish milling step, or the like. In a puffing and drying step, the puffing process is performed, deformation of the shape of the rice grains is prevented. A quick-cooking rice product having an excellent outer appearance is provided through finish drying process after the puffing process. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing instant rice from rice grain raw materials such as long grain seeds and medium grain seeds.

  Conventionally, quick-cooked rice is known as rice that can be cooked in a time much faster than the time required for normal rice cooking, and instant rice is known as one of them. Instant rice has a particularly fast cooking time among fast-cooked rice. For example, it can be cooked in about 5 to 10 minutes.

  This instant rice manufacturing method is disclosed in, for example, Patent Document 1. In this production method, after the primary split rice of the raw material is first soaked, primary alpha conversion (normal pressure steaming), preliminary drying, finished rice (high moisture rice), secondary soaking, secondary alpha conversion (normal pressure steaming), It was a method for producing instant rice through the steps of single graining and finish drying.

Japanese Patent No. 4099036

However, in the instant rice manufacturing method, since the raw rice grains are soaked in the warm water (about 80 ° C) in the soaking tank in the primary soaking and secondary soaking processes, a large amount of warm water is used, so this waste water treatment equipment is required. There was a problem that the cost of the manufacturing equipment was high. In addition, since the above-described manufacturing method is performed by immersing the raw rice grain raw material in the water of the immersion tank in the hydration process, there is a concern that cracks may occur on the surface of the rice grain. When the surface of the rice grains is cracked, the nutrients inside the rice grains are eluted, and the shape of the rice grains collapses and the appearance of the product may deteriorate.
In view of the above problems, it is a technical object of the present invention to provide an instant rice manufacturing method that does not require waste water treatment equipment and can improve the appearance of the product.

The instant rice production method of the present invention comprises:
A pre-pressurized steaming step of steaming raw rice grains of split rice or brown rice with pressurized steam;
A quantitative hydration step of quantitatively hydrating rice grains discharged from the pre-pressurized steaming step;
Finished pressurized steaming step of steaming the rice grains discharged from the quantitative water adding step with pressurized steam;
A finishing rice milling process for finishing and polishing the rice grains discharged from the finishing pressure steaming process;
A quantitative hydration step for quantitatively hydrating rice grains discharged from the finished rice polishing step;
A swollen drying step of drying the rice grains discharged from the quantitative water addition step by heating;
A finish drying step of heating and drying the rice grains discharged from the expansion drying step;
The technical means of providing these in order is taken.

In the instant rice production method of the present invention, the method of hydrating the raw rice grains is not a dipping method but a quantitative hydration method, so that the required amount of water is quantitatively supplied to the raw rice grains to generate surplus water. Since no drainage occurs, no wastewater treatment facility is required. For this reason, the cost of a manufacturing facility can be reduced and the running cost concerning wastewater treatment becomes unnecessary.
In addition, according to the present invention, when the raw rice grains are quantitatively hydrated, in the pre-pressurized steaming step, which is the previous step, in advance, the pre-pressurized steaming treatment is not performed at normal pressure steaming, but by surface steaming by pressure steaming. It is processed and the rice grain surface is uniformly α-formed without cracking by pressure steaming applied to the rice grain from the entire circumference. For this reason, since the rice grain surface layer has been toughened and has toughness, it is possible to hydrate up to the target moisture value without causing cracks in the surface of the rice grain during the quantitative hydration, and also in the rate of hydration Rapid hydration can be performed without requiring much consideration such as performing slowly, and the hydration time can be shortened.
Furthermore, in the present invention, the rice grain surface layer is α-ized and has toughness, which means that the rice grain shape is prevented from collapsing in the post-alpha process and the finishing rice process, etc. It can be held in a proper shape, and further, in the subsequent expansion and drying process, the expansion process can be performed without breaking the shape of the rice grains. For this reason, the product which finally passed through finish drying after this can be made into an instant rice product with good appearance in which the shape of the rice grains is not broken.

The manufacturing flow of the instant rice of this invention is shown. The longitudinal cross-sectional view of the atmospheric steaming apparatus and pressure steaming apparatus in this invention is shown. The watering apparatus and tempering apparatus in this invention are shown. The longitudinal cross-sectional view of the cooler in this invention is shown. The longitudinal cross-sectional view of the vertical grinding-type rice mill in this invention is shown. The longitudinal cross-sectional view of the swelling drying processing apparatus in this invention is shown. The longitudinal cross-sectional view of the net drying apparatus in this invention is shown.

  Hereinafter, an embodiment of the present invention will be described with reference to the manufacturing flow of instant rice in the present invention shown in FIG.

  As the raw rice grains applied to the present invention, brown rice such as long grain seeds or medium grain seeds, or split rice (attached) rice can be used.

  In the following description, the raw rice grains are divided rice (hereinafter referred to as “raw rice grains”) having a polished rice yield of 95% to 98%. A known rice milling machine may be used as appropriate for the rice milling method for obtaining separated rice.

Step 1 (atmospheric pressure cooking process):
This step is a normal pressure steaming step in which the raw rice grains are cooked and heated (preliminary heating) at normal pressure in preparation for the next step. FIG. 2 shows an atmospheric steaming device 1 used in the present atmospheric steaming process. The atmospheric steaming apparatus 1 has cylindrical polygonal rotary drums 3 and 4 each having a porous wall and are vertically installed inside a sealed machine wall 2. The rotary drum 3 installed horizontally in the upper stage is disposed in a downwardly inclined manner from the supply side at one end to the discharge side at the other end so that the raw rice grains flow down. The one end supply side of the rotary drum 3 is inserted with the discharge side of the raw material supply pipe 5, and the other end discharge side is one end supply in the rotary drum 4 in which the raw material discharged from the rotary drum 3 is placed horizontally. It is communicated by a lower transfer pipe 6 for transferring and feeding to the side.

  Similarly to the rotary drum 3, the rotary drum 4 is also arranged in a downwardly inclined manner from the one end supply side to the other end discharge side so that the raw rice grains flow down. The discharge side of the pipe 6 is inserted, and the other end discharge side communicates with the lower transfer pipe 7 for transferring and supplying the raw material to the next process (preliminary pressure steaming process / step 2). Each of the rotary drums 3, 4 is provided with connecting plates 3 c, 4 c for horizontally connecting the rotary shafts 3 a, 4 a to the inner center of the rotary drums 3, 4 c and connecting the rotary shafts 3 a, 4 a to the inner wall of the rotary drum. It can be freely rotated by the bearings of the rotary shafts 3a and 4a. One end of each of the rotating shafts 3a and 4a is connected to a motor 9 via pulleys 3b and 4b and a power transmission belt 8.

  Below each of the rotating drums 3, 4, steam jet pipes 10, 11 having a length extending over the entire length of the rotating drums 3, 4 are provided horizontally. The steam supply source side of the steam ejection pipes 10 and 11 is connected to a steam supply source (not shown) via a steam pipe 12 and an on-off valve 13. The bottom part 2a of the machine frame 2 is arranged in a downwardly inclined shape toward one side, and the inclined lower part is for draining water accumulated in the machine wall 2 as water droplets. A drainage part 2b is provided. A feed valve 5 a is provided on the upper supply side of the raw material supply pipe 5.

  The number of rotations of the rotary drums 3 and 4 is not particularly limited, but the time for the raw material to pass through the rotary drums 3 and 4 is 10 seconds to 300 so that the raw rice grains do not crack. Set appropriately to be within the range of seconds. Further, the supply amount of steam to be filled in the machine wall 2 from the steam ejection pipe 10 is also set as appropriate so as not to cause shell cracks.

The operation of Step 1 (normal pressure cooking process) will be described.
This normal pressure steaming process supplies the saturated water vapor | steam of about 100 degreeC from the steam jet pipe 10 in the normal pressure state in the machine wall 2 of this normal pressure steaming apparatus 1 using the normal pressure steaming apparatus 1 of the said structure. In addition, while rotating the rotary drums 3, 4, one lot of raw rice grains is supplied to the one end supply side of the rotary drum 3 via the feed valve 5 a and the raw material supply pipe 5.

  The raw rice grains supplied into the rotary drum 3 are covered with the steam (saturated water vapor) at normal pressure, whereby the air between the raw rice grains is expelled by the steam and the steam fills the gaps. And the raw material is heated. At this time, the raw rice grains flow down toward the other end discharge side while being stirred by the rotation of the rotary drum 3. The air between the rice grains is exhausted from an air exhaust part 2c comprising an exhaust pipe and an exhaust fan provided at the upper part of the machine wall 2. The raw material that has passed through the rotary drum 3 is discharged from the discharge side at the other end, and then supplied into the rotary drum 4 through the lower transfer pipe 6. Also in the rotary drum 4, the raw rice grains are heated while being stirred and transferred in the same manner as the operation of the rotary drum 3 and discharged from the other end discharge side. The normal pressure cooking time until the raw rice grains are charged and discharged is preferably within about 1 minute so as not to cause cracks in the rice grains. In this way, the raw rice grains are preliminarily heat-treated at a temperature of about 100 ° C. without causing cracking of the shells, while being filled with saturated steam between the rice grains in preparation for the next pressure steaming process. Processing to exclude air is performed. The raw rice grains discharged from the other end discharge side of the rotating drum 4 are sent to the pre-pressurized steaming step (step 2) through the lower transfer pipe 7. Since steam is used in this normal pressure steaming process, the amount of water used is small and the amount of drainage from the discharge part 2b is very small.

  In addition, the process of this step 1 (atmospheric pressure cooking process) is not an indispensable constituent element in the present invention, and providing it improves the time production efficiency and has a good quality product (instant rice) with no variation. ) Can be manufactured.

Step 2 (pre-pressure steaming process):
This step is a pre-pressurized steaming step in which the surface layer of the raw rice grains discharged from the previous step normal pressure steaming step (atmospheric pressure steaming device 1) is pregelatinized. In FIG. 2, the pressure cooking apparatus 14 used in this pre-pressure steaming process is shown. The pressure steaming device 14 has a belt conveyor 16 installed in a sealed machine wall 15. The belt conveyor 16 includes a net-like transport endless belt 16a, and a driving roller 16b and a driven roller 16c that span the transport endless belt 16a. At the bottom of the machine wall 15, a pressurized heating steam supply unit 17 that supplies pressurized heating steam is disposed in a sealed space formed by the machine wall 15. The pressurized heating steam supply unit 17 includes a pressurized heating steam supply source (not shown) and a supply port (at the bottom of the machine wall 15 provided with the pressurized heating steam generated by the pressurized heating steam supply source ( (Not shown) and a steam pipe 17a to be supplied, and an on-off valve 17b is disposed in the middle of the steam pipe 17a.

  An inclined chute tube 15 a for supplying rice grains (raw material) from the previous process onto the belt conveyor 16 is disposed on the conveying start end side of the belt conveyor 16. Further, the upstream end portion of the inclined chute tube 15a communicates with the discharge side of the lower transfer tube 7, and the rice grains discharged from the previous step 1 (atmospheric pressure cooking step) are removed in the step 2 (preliminary step). It is now accepted for pressure cooking process.

  A plurality of valves are built in the lower transfer pipe 7 so that the pressurized heated steam in the machine wall 15 does not escape to the outside when the rice grain supply from Step 1 is received. The plurality of valves are arranged in the lower transfer pipe 7 in order from the top, shock absorbing damper 7a for absorbing the drop impact of rice grains, upper butterfly valve 37b, lower butterfly valve 37c, rice grains supplied from the previous step. A loosening plate 37d for loosening the lump is disposed at an arbitrary interval. An air vent valve 7e is provided in a gap 7f between the upper butterfly valve 7b and the lower butterfly valve 7c in the lower transfer pipe 7.

  The operation of the plurality of valves in the lower transfer pipe 7 will be described. When supplying the rice grain to the pressure steaming device 14 via the lower transfer pipe 7, first, the upper butterfly valve 7b and the lower butterfly valve 7c are both closed and the air vent valve 7e to the gap 7f. Release the pressure (pressurized heating steam). Next, the upper butterfly valve 7b is opened, and rice grains are supplied from the upper supply side into the gap 7f while adjusting the flow rate according to the opening degree of the shock absorbing damper 7a. When a predetermined amount of rice grains accumulates in the gap 7f, the air vent valve 7e is closed, the upper butterfly valve 7b is closed, and then the lower butterfly valve 7c is opened. The rice grains fall by their own weight and are supplied to the pressurized steaming device 14 (in the inclined chute tube 15a) through the loosening plate 7b. By repeating the above sequence, one lot of rice grains is sequentially supplied into the pressure cooking apparatus 14.

  A lower transfer pipe 18 for discharging the rice grains whose surface of the rice grains are pregelatinized in the pressure steaming device 14 to the outside of the machine wall 15 is disposed on the conveyance terminal side of the belt conveyor 16. In the inside of the lower transfer pipe 18, similarly to the lower transfer pipe 7, when the rice grains that have been pregelatinized are discharged to the outside of the machine wall 15, the pressurized heated steam in the pressurized steaming device 14 is discharged. A plurality of valves are arranged so that the pressure inside the machine wall 15 does not decrease due to the outside being pulled out. The plurality of valves include an impact absorbing damper 18a for absorbing the falling impact when the brown rice that has been processed in the pressurized steaming device 14 is discharged and dropped into the lower transfer pipe 18, and an upper butterfly valve. 18b and a lower butterfly valve 18c are sequentially arranged from the upper part to the lower part at an arbitrary interval. An air vent valve 18d is provided in a gap 18e between the upper butterfly valve 18b and the lower butterfly valve 18c in the lower transfer pipe 18. A drainage part 19 is provided at the bottom of the machine wall 15 for draining water accumulated in the pressure steaming device 14 as steam droplets.

  The operation of the plurality of valves in the lower transfer pipe 18 will be described. When the rice grains that have been subjected to the pregelatinization treatment are discharged from the pressure steaming device 14 through the lower transfer pipe 18, first, the upper butterfly valve 18b and the lower butterfly valve 18c are both closed, and the gap 18e is closed. The pressure (pressurized heated steam) at is removed from the air vent valve 18d. Subsequently, the upper butterfly valve 18b is opened, and the flow rate of supplying the discharged rice grains into the gap 18e by adjusting the opening of the shock absorbing damper 18a is adjusted. When a predetermined amount of the rice grains have accumulated in the gap 18e, the air vent valve 18d is closed and the upper butterfly valve 18b is closed, and then the lower butterfly valve 18c is opened. As a result, the rice grains fall to the outside due to their own weight. By repeating the above sequence, one lot of brown rice that has been processed is sequentially discharged out of the pressure cooking apparatus 14.

The operation of Step 2 (preliminary pressure steaming step) will be described.
First, saturated steam pressurized from the pressurized heated steam supply unit 17 is supplied to the inside of the machine wall 15 of the pressurized steaming device 14, and the pressure inside the machine wall 15 is within a range of 0.001 MPa to 0.3 MPa. Adjust so that it is an arbitrary set value. Thus, when the pressure inside the machine wall 15 becomes 0.001 MPa to 0.3 MPa, the temperature inside the machine wall 15 is about 105 ° C. to about 145 ° C. Next, the rice grain preheated by the previous process (step 1: atmospheric pressure cooking process) is supplied to the conveyance start end side of the belt conveyor 16. The time for pressure steaming the supplied rice grains is preferably in the range of 2 to 5 minutes, and the conveying speed of the belt conveyor 16 is adjusted so as to be an arbitrarily set value within the time range. Since the supplied brown rice is preheated, the heating time is not required, and the processing can be performed for a short time such as the pressure steaming processing time. Under such conditions, the rice grains are subjected to pressure steaming treatment for 2 to 5 minutes in a pressurized state of 0.001 MPa to 0.3 MPa (temperature: about 105 ° C. to about 145 ° C.), whereby the surface layer becomes α (About 10% to 20%) and then discharged from the lower transfer pipe 18. The gelatinization degree of the rice grain surface layer varies depending on the set values within the range of the pressure state and the pressure steaming treatment time. Within the above range, the degree of alpha conversion is large (large) in the case of setting processing at a high pressure for a long time, and conversely, the degree of alphaization is small (small) in the case of a setting process for a short time at low pressure. In addition, since steam is also used in the pre-pressurized cooking step, the amount of water used is small, and the amount of drainage from the discharge unit 19 is extremely small.

  As described above, the merit of steaming the rice grains is that even if the grains of the rice grains are in contact with each other, each rice grain is uniformly distributed from the entire circumference direction by saturated steam that is smoothly filled between the grains by the pressure. Since the steaming can be performed under pressure, the surface layer of each rice grain becomes uniform and the variation is reduced. In this point, in the hydration process (step 3), which is a subsequent process, there is an effect that no hydration unevenness for each rice grain or hydration (moisture content) unevenness in one grain of rice occurs, and a higher quality instant rice is produced. It is valid.

Step 3 (quantitative water addition process) and step 4 (moisture conditioning process):
In this step, a quantitative water addition step of adding water up to a predetermined moisture value with respect to the rice grains in which the surface layer discharged from the pre-pressurization steaming step (pressure steaming device 14) in the previous step is pregelatinized, and moisture unevenness between the rice grains This is a moisture refining process for uniforming and refining (tempering). FIG. 3 shows a quantitative hydration apparatus 20 used in the quantitative hydration process and a tempering apparatus 25 used in the moisture conditioning process.

Configuration of the quantitative water adding device 20:
The quantitative hydration apparatus 20 does not need to use a special hydration apparatus, and may be, for example, a hydration apparatus as shown in FIG. The quantitative water adding device 20 includes a supply tank 21 for storing rice grains whose surface layer has been made α in the previous step <Step 2 (preliminary pressure steaming step)>, and the discharge side of the supply tank 21 is a feeding valve (rotary valve). ) To the raw material supply line 23 via 22. The discharge side of the raw material supply line 23 is connected to the supply side of the agitation transfer unit 24 described later. A shower water spray nozzle 23a for quantitatively sprinkling water for hydrating rice grains is provided inside the supply pipe 23, and an umbrella-shaped rice grain flow restriction is provided above the shower water spray nozzle 23a. A plate 23b is provided. The agitating / transferring portion 24 is provided with a stirring cylinder 24a as a machine wall, connected to the supply side of the stirring cylinder 24a, and provided with a discharge portion 24e on the discharge side. A stirring transfer shaft 24b that is rotatable by bearings provided at both left and right ends is built in the stirring tube 24a. The agitation transfer shaft 24b is provided with agitation transfer blades 24c that give the agitation and transfer action to the brown rice at equally spaced positions in the longitudinal direction. One end side of the agitation transfer shaft 24b is connected to a motor 24d through a pulley and a power transmission belt. The shower water spray nozzle 23a is connected to a pressurized water supply unit (not shown) so that the amount of water spray can be adjusted.

Configuration of the tempering device 25:
The tempering device 25 includes a cylindrical thermostatic tank portion 26. The upper supply port of the tank part 26 is connected to the discharge part 24e of the water adding device 20 via a flow path 26a. On the other hand, a rotary valve 26b is provided at the lower outlet of the tank part 26, and the rotary valve 26b is a reflux part for refluxing the hydrated rice grains discharged from the rotary valve 26b into the tank part 26. 27. As the reflux unit 27, a known bucket type elevator or a pressurized air type air conveyance device may be used. The reflux path of the reflux unit 27 is provided with an optional sample collection means (for example, a sample collection path) 28 for collecting the sample of the rice grains after hydration, and the sample collection means 28 has a known grain moisture meter 29. Connect. Accordingly, the moisture content of rice grains passing through the reflux path is measured at any time.

  Further, a flow path switching valve 30 is provided on the discharge side of the reflux section 27, and the flow path 30a on the side refluxed to the tank section 26, the quantitative water adding apparatus 20 or the next process (atmospheric pressure steaming process / step 5). It is possible to switch to the flow path 30b on the side facing the head. further. A flow path switching valve 31 is provided on the downstream side of the flow path 30b, and the flow path 31a flows back to the supply tank side of the water adding device 20 and the flow path 31b toward the next process (normal pressure steaming process / step 5). Can be switched.

The operation of Step 3 (quantitative water addition step) will be described.
When the rice grains that have been subjected to the α-layer treatment in the previous process (Step 2 <preliminary pressure steaming process>) are sequentially fed out from the supply tank 21 by the rotation of the rotary valve 22 and flow down in the raw material supply pipe 23. The water is supplied into the stirring cylinder 24a while receiving a quantitative watering of the shower water from the shower watering nozzle 23a. The rice grains supplied to the stirring cylinder 24a are subjected to a rotating action of the stirring means 24d comprising the stirring transfer part shaft 24b and the stirring transfer blade 24c, are transferred while being stirred with shower water, and are discharged from the discharge part 24e. . Thus, when the rice grains are stirred and transferred through the stirring cylinder 24a, the surface layer is uniformly alpha-treated so that the surface layer has elastic toughness. Water is added from the entire surface of the rice grain to the inside without causing cracks on the surface. In addition, the amount of water mixed with the rice grains is set to a sufficient amount so that excess water (drainage) is not generated as much as possible, and the speed of water absorption into the rice grains is increased, and the water target value (target) The hydration time from 20% to 28% of the water content can be shortened. At that time, since the surface layer of the rice grain is uniformly α-treated, uniform hydrolysis can be performed from the entire surface of the rice grain to the inside without causing cracks on the surface of the rice grain. In addition, since the crack is not produced in the rice grain surface, since the rice grain starch does not elute in the below-mentioned atmospheric pressure cooking process etc., a rice grain shape is also maintained, without a nutrient component reducing.

  The water addition rate in the present invention is in the range of 20% / h to 80% / h, and if it is between these, water can be absorbed to the target moisture content without cracking on the surface of the rice grain. In addition, the larger the surface layer α-degree of rice grain, the closer to 80% / h (the faster the rate of water addition), and the lower the degree of α-ization (the less), the closer to 20% / h. (Slow water addition rate). As described above, the adjustment of the degree of surface layer α-ization of the rice grains is performed in Step 2 (preliminary pressure steaming step). In addition, in the hydration process, the present invention simplifies the production equipment, which does not require wastewater treatment equipment, by adjusting the amount of hydration added to the rice grains and mixing so that excess water is not discharged as much as possible. There is an effect of reducing the capital investment cost.

The operation of Step 4 (moisture refining step) will be described.
In the present step 4, one lot of rice grains hydrated in the previous process (step 3 <quantitative hydration process>) is first supplied to the tank 26 in the tempering device 25 through the flow path 26a and deposited. After the accumulation of one lot of rice grains is completed, the rice grains in the tank 26 are fed out in order from the ones deposited in the lower part by driving the rotary valve 26b and the reflux unit 27 to be conditioned in the tank 26. Is done. During the circulation, the sampled rice grain sample 28 is collected by the sample collecting means 28 and sent to the grain moisture meter 29 to measure the moisture content of the rice grain sample. When the measured moisture content is lower than the target moisture content described below, the rice grains are again refluxed to the hydration device 20 through the flow path switching valves 30 and 31, and re-hydrated. After that, it is stored in the tempering device 25 and tempered again to bring it closer to the target moisture content, and the variation in the moisture value between the rice grains is reduced.

  In the tempering step, the water content of the hydrated rice grains is uniformized without variation between the rice grains so that the water content of the hydrated rice grains becomes an arbitrary target water content within the range of 20% to 28%. The time required for the tempering step is appropriately set within a range of about 10 minutes to 20 minutes. At this time, the temperature in the tank 26 is preferably in the range of 50 ° C to 70 ° C. In addition, because the tempering process moves nutrients such as minerals contained in the cocoon layer and germ of the rice grain (split rice) to the endosperm part, the rice grain will eventually be refined into an instant rice product. The above nutrients are retained.

Step 5 (normal pressure cooking process):
This step is a normal pressure steaming step of steaming and heating (preliminary heating) the rice grains discharged from the tempering step (tempering device 25) of the previous step, and the normal pressure steaming device used in this step is the step described above. 1 may be the same as shown in Fig. 1 (see the atmospheric steaming device 1 in step 1 and Fig. 2). For this reason, description of the apparatus is omitted. In addition, the process of this step 5 (atmospheric pressure cooking process) is not an essential constituent element in the present invention, as in the case of the above-mentioned step 1. However, the provision of the process improves the temporal production efficiency, and the quality without variation. Good instant rice products.

The operation of Step 5 (normal pressure steaming process) will be described.
This step 5 has the same effect as the above step 1 (atmospheric pressure cooking process), and the rice grains discharged from the tempering process of the previous process are saturated at about 100 ° C. for the final pressure cooking process of the next process. Heating (preheating) is performed with water vapor (normal pressure state). In addition, in order to prepare for the next pressurizing steaming step, a process of excluding air by filling saturated steam between the rice grains is performed, whereby the air does not become a heat insulating action between the rice grains in the finishing pressurizing steaming step, The pressure steaming process is efficient, and there is an effect that the variation in the pressure steaming is reduced and the quality is improved. Also in this step 5, it is preferable that the atmospheric steaming is within about 1 minute as in the case of step 1.

Step 6 (finishing pressure cooking process):
This step 6 is a finish pressure steaming process in which the same action as the above step 2 (preliminary pressure steaming process) is performed and the brown rice discharged from the normal pressure steaming process of the previous process is subjected to a pregelatinization finish. In step 6, the same pressure steaming apparatus as that used in step 2 is used (see atmospheric steaming apparatus 14 in step 2 and FIG. 2). For this reason, description of the apparatus is omitted.

The operation of Step 6 (finishing pressure cooking process) will be described.
In this step 6, the pressure steaming action performed in step 2 (preliminary pressure steaming step) is caused to act on the rice grains again to advance the gelatinization of the rice grains. The specific action of Step 6 is to supply the rice grains preheated in Step 5 (atmospheric pressure cooking process) to the atmospheric pressure steaming device 14 and perform α-ization under pressure cooking conditions almost the same as in Step 2. As pressure steaming conditions, the pressure in the pressure steaming device 14 is adjusted so as to be an arbitrarily set value within the range of 0.1 MPa to 0.3 MPa (temperature at this time: about 120 ° C. to about 145 ° C.). The pressure steaming time (conveying speed of the belt conveyor 16) is adjusted to be an arbitrarily set value within a range of 2 to 10 minutes. By finishing the preheated rice grains in such a manner, the time for heating the rice grains is shortened, and the rice grains are subjected to the pressure steaming action from the whole surface direction of the rice grains for a predetermined time to be pregelatinized. The By the finishing pressure steaming action of Step 6, the degree of alpha conversion of the rice grains becomes about 95% to 100%. In addition, in step 5 (normal pressure cooking process) and step 6 (finishing pressure cooking process), by adjusting the amount of water used for cooking so as not to generate surplus water, a wastewater treatment facility is required. do not do.

Step 7 (cooling process):
This step 7 is a cooling process for removing the heat (rough heat) from the surface of the rice grain that has been subjected to the pregelatinization process in the previous process, and facilitating the subsequent drying process. This cooling process uses the cooling apparatus 32 shown in FIG. The cooler 32 is provided with a belt conveyor 34 in the interior surrounded by the machine wall 33. A supply unit 35 for supplying rice grains (finished α-finished) discharged from the previous process onto the belt conveyor 34 is disposed at one upper end of the machine wall 33. In addition, a discharge unit 36 for discharging the rice grains that have been allowed to cool from the conveying terminal end on the belt conveyor 34 is disposed at the other lower end of the machine wall 33.

  The belt conveyor 34 includes a net-like transport endless belt 34a, and a driving roller 34b and a driven roller 34c that span the transport endless belt 34a. An outside air inlet 37 formed in a horizontally long shape along the longitudinal direction of the belt conveyor 34 is formed in the machine wall 33 on the side surface of the cooler 32. The machine wall 33 on the upper surface is provided with a suction exhaust port 38 having a size corresponding to substantially the entire area of the conveying surface of the belt conveyor 34. The suction exhaust port 38 is connected to an exhaust tube 41 through a suction tube 39 and an exhaust fan 40.

The operation of Step 7 (cooling process) will be described.
In this step 7, the rice grains that have been subjected to the finish steaming process (finished α-formation process) in the previous step are sequentially supplied from the supply unit 35 to the transfer start end side of the transfer endless belt 34a. While the rice grains supplied onto the transport endless belt 34a are transported by the belt conveyor 34, the outside air taken in from the outside air inlet 37 generated by the suction of the exhaust fan 40 from below the transport endless belt 34a. Due to the ventilation, the heat (coarse heat) of the surface of the rice grains is taken away, the surface temperature is lowered, and the rice is sequentially discharged from the discharge part 36. The discharged rice grains have a moisture content in the range of about 20% to 25%.

Step 8 (finishing and polishing process):
In the final rice milling process, high moisture rice grains having a water content of about 20% to 25% discharged from the previous process are finished and polished. In the final rice milling process, for example, a known vertical grinding-type rice mill 42 shown in FIG. 5 is used. The vertical grinding-type rice mill 42 has a configuration of a whitening roll 45 formed by axially attaching a grindstone roll 44 to a rotating main shaft 43 and a gap (rice milling chamber) 46 at a predetermined interval in the outer peripheral direction of the whitening roll 45. The disposed perforated screen 49 and the removal removal chamber 50 disposed in the outer peripheral direction of the perforated screen 49 are configured. The rotating main shaft 43 is pivotally supported by bearings 43a disposed at upper and lower arbitrary positions, and the lower end portion is connected to the output side of the motor 54 via the pulley 51 and the power transmission belt 52 that are attached to the shaft. It connects with the pulley 53 which becomes, and is comprised rotatably by this. Further, a product discharge portion 58 is formed at the lower end of the semen chamber 46, and the product discharge portion 58 includes a resistance lid 55, a product discharge port 56 and a product discharge rod 57.

  On the other hand, the upper end portion of the semen chamber 46 communicates with a raw material supply port 59 disposed further above. The raw material supply port 59 is provided with a raw material supply adjusting unit 60. Note that the lower end portion of the debris storage chamber 50 communicates with the exhaust fan 47 through the pipe 48 so as to suck out and discharge the soot out of the apparatus.

The effect | action of this finishing rice polishing process is demonstrated.
In this finishing rice milling process, first, the motor 54 of the vertical grinding-type rice milling machine 42 is started to rotate to rotate the grindstone roll 44, and the resistance of the product discharger 58 is adjusted to start the operation. Make settings. Thereafter, when the rice grains discharged from the previous step (water content of about 20% to 25%) are supplied from the raw material supply port 59, the rice grains are mixed with the grindstone roll 44 and the like while flowing down the scouring chamber 46 from above. The bran layer on the surface of the rice grains is gradually removed by grinding action or the like by contact to become polished rice, which is discharged from the product discharge portion 58.

Step 9 (quantitative water addition step):
This quantitative hydration process is a process performed for instant processing, and this quantitative hydration process further hydrates the rice grains (alphanized and polished rice) discharged from the finishing rice polishing process of all processes to increase the water content. Process. The mechanical equipment used in this quantitative hydration process may be the same as that described in step 3 (quantitative hydration process). Although detailed description is omitted, the water treatment is performed until the moisture content of the rice grains falls within the range of 40% to 55% by quantitative watering of the shower water from the shower water nozzle 23a. At this time, since the rice grains are already pregelatinized (95% to 100%), there is no concern about surface cracks and there is no concern about the shape loss of the rice grains.

Step 10 (moisture conditioning process):
In this moisture tempering process, as in step 4 (moisture tempering process), one lot of rice grains hydrated in the previous process (step 9 <quantitative hydration process>) is tempered. The time required for the tempering process is set as appropriate within the range of about 10 to 20 minutes as in Step 4, and the temperature in the tank 26 is within the range of 50 to 70 ° C. It is preferable that

Step 11 (swelling drying process):
The main swelling and drying step is a step of performing a swelling and drying process at a superheated temperature on the rice grains (alphatened and refined rice) having a water content of 40% to 55% discharged from the previous step. An example of the expansion drying processing apparatus 61 which performs the expansion drying processing is shown in FIG. The expanded drying processing apparatus 61 includes a transfer perforated plate 62. The transfer perforated plate 62 includes a large number of ventilation holes for transferring rice grains while drying, and is disposed horizontally between the upper machine casing 63a and the lower machine casing 63b. Above the perforated plate 62, a perforated plate 64 similar to the perforated plate 62 is provided, and a rice grain transfer path 65 having a height capable of transferring rice grains is formed. A rice grain supply port 66 is disposed on one end side of the rice grain transfer path 65, and a rice grain discharge port 67 is disposed on the other side. The perforated plate 62 (rice grain transfer path 65) can vibrate and transfer rice grains from the rice grain supply port 66 side to the rice grain discharge port 67 side by the vibration action of the vibration motor 68 disposed in the lower machine casing 63b. It is like that. The lower machine casing 63 b is held by a base stand 69 via a plurality of springs 68.

  On the other hand, a hot air generation and supply device 70 is provided. The hot air generating / supplying device 70 has a burner portion 70a composed of a kerosene burner or the like and a blower fan 70b. The blower fan 70b communicates with the lower machine casing 63b through a hot air transfer pipe 70c and a hot air supply port 70d, and is configured so that hot air is supplied below the transfer hole plate 62. The blower fan 70b and the burner portion 70a are also connected by a hot air transfer pipe 70c. The hot air transfer pipe 70c may be appropriately provided with an air volume adjusting valve. The upper machine casing 63a is provided with an air exhaust port 71 so that hot air ventilated from below the transfer perforated plate 62 can be exhausted. A suction device (not shown) may be connected to the air exhaust port 71. In this step 11, the expanded drying processing device 61 has been described as an example. However, in addition to the expanded drying processing device 61, a microwave irradiation drying device or the like may be used, and rice grains are heated at a high temperature (overheating temperature) of about 150 ° C. to 250 ° C. The purpose is to dry.

  The operation of the expansion drying process will be described. In the expanded drying processing apparatus 61, the rice grains having a water content of 40% to 55% discharged from the step 10 (moisture conditioning process) supplied from the rice grain supply port 66 to the perforated transfer plate 62 (rice grain transfer path 65). (Alphatized and polished rice) is subjected to an aeration effect of superheated hot air from below while being transferred in a downstream direction while receiving an oscillating action, and is dried and expanded. The temperature of the superheated hot air is preferably about 150 ° C to 250 ° C, and the time for passing the superheated hot air is preferably 10 minutes to 20 minutes. The moisture content of the rice grains is preferably about 20% to 25%.

Characteristic actions of the present invention:
In this expansion and drying step, expansion processing is performed by the ventilation action of superheated hot air, but the surface of the rice grains does not tear and the shape of the rice grains does not collapse. This is because the surface of rice grains can be made α-tough and can be hydrated without causing cracks, especially by performing the quantitative hydration process of step 3 after the pre-pressurized steaming process of step 2 in the conventional treatment process. caused by. Further, since the rice grains having toughness on the surface after the hydration treatment are supplied to the finishing pressure steaming step of Step 6, the rice grains are not cracked even when the rice grains are gelatinized to about 100%. The alpha process can be completed while maintaining the shape. In addition, in the finishing rice polishing step of Step 8, the rice grains are subjected to the finishing rice treatment. However, since the rice grains to be polished have already been almost completely α and the whole rice grains have toughness, the shape of the rice grains does not collapse. Thereafter, in the expansion and drying process of step 11, the expansion process is performed by the ventilation action of the superheated hot air. However, the rice grains have overall toughness due to the substantially complete α formation, so the shape of the rice grains is destroyed. The expansion process is performed without any problem.

Step 12 (finish drying process):
In the final drying step, the expanded rice grains discharged from the previous step are finish-dried to a moisture content of 12% or less. In the final drying process, a known drying apparatus may be used. For example, the net drying apparatus 72 shown in FIG. 7 can be used. The net drying device 72 is a modification of the cooling device 32 shown in FIG. 4 and can supply hot air from below the net-like transport endless belt 34a. That is, the hot air generation and supply device 73 is connected to the lower part of the main body of the net drying device 72. The hot air generation and supply device 73 includes a burner unit 73a, a blower fan 73b, and a hot air transfer pipe 70c, and is configured to be able to supply and vent hot air from below the transport endless belt 34a via the hot air transfer pipe 70c. In addition, about the part of the same structure as the said cool cooling apparatus 32, description is abbreviate | omitted for the above-mentioned.

  The operation of the finish drying process will be described. The finishing drying process uses the net drying device 72 to transfer the rice grains (moisture content: about 20% to 25%) that have undergone the expansion process in the previous step 12 from the supply unit 35 to the conveyance start end side of the conveyance endless belt 34a. Supply. The rice grains supplied to the conveying start end side are subjected to a hot air flow of 80 ° C. to 100 ° C. from the hot air generating and supplying device 73 while being conveyed by the conveying endless belt 34a, and finish-dried to a moisture content of 12% or less, and discharged. It is discharged from the part 36. In addition, it is preferable that the ventilation time of the hot air is within 20 minutes to 30 minutes.

  In the above embodiment, the split rice was described as an example, but as described above, the rice grain applicable in the present invention may be brown rice.

  Moreover, as shown in the said Example, this invention can produce a product instant rice efficiently from a raw rice grain by continuous processing instead of batch processing by using each apparatus of the said step 1-step 12 continuously. It is a manufacturing method that can.

  Since the present invention is a manufacturing method that does not require wastewater treatment in an instant rice manufacturing method, it can reduce equipment costs that require wastewater treatment equipment in the manufacturing equipment, and is useful as an instant rice manufacturing equipment. .

DESCRIPTION OF SYMBOLS 1 Normal pressure steaming apparatus 2 Machine wall 2a Bottom part 2b Discharge part 2c Air exhaust part 3 Rotating drum 3a Rotating shaft 3b Pulley 3c Connecting plate 4 Rotating drum 4a Rotating shaft 4b Pulley 4c Connecting plate 5 Raw material supply pipe 5a Feeding valve 6 Downward transfer pipe 7 Lower transfer pipe 7a Shock absorbing damper 7b Upper butterfly valve 7c Lower butterfly valve 7d Unwinding plate 7e Air vent valve 7f Gap 8 Power transmission belt 9 Motor 10 Steam ejection pipe 11 Steam ejection pipe 12 Steam pipe 13 On-off valve 14 Pressurizing steaming device 15 Machine Wall 15a Inclined Chute Pipe 16 Belt Conveyor 16a Endless Belt 16b Drive Roller 16c Driven Roller 17 Pressurized Heat Steam Supply Unit 17a Steam Pipe 17b Opening Valve 18 Lower Transfer Pipe 18a Shock Absorbing Damper 18b Upper Butterfly Valve 18c Lower Butterfly Valve 18d Air vent valve 18e Clearance DESCRIPTION OF SYMBOLS 9 Drain part 20 Water supply apparatus 21 Supply tank 22 Feed valve 23 Supply line 23a Spray nozzle 23b Rice grain flow control board 24 Stirring transfer part 24a Stirring cylinder 24b Stirring transfer shaft 24c Stirring transfer blade 24d Motor 24e Discharge part 25 Tempering apparatus 26 Tank part 26a Flow path 26b Feed valve 27 Recirculation part 28 Sample collecting means 29 Grain moisture meter 30 Flow path switching valve 31 Flow path switching valve 31a Flow path 32 Cooling device 33 Machine frame 34 Belt conveyor 34a Conveying endless belt 34b Drive roller 34c Driven roller 35 Supply Unit 36 Discharge Unit 37 Outside Air Intake 38 Suction Exhaust Port 39 Suction Pipe 40 Exhaust Fan 41 Exhaust Pipe 42 Vertical Grinding Rice Mill 43 Rotating Spindle 43a Bearing 44 Grinding Wheel Roll 45 Polishing Roll 46 Milling Room 47 Exhaust Fan 48 Line 49 Perforated screen 50 Removal Chamber 51 Pulley 52 Power transmission belt 53 Pulley 54 Motor 55 Resistive lid 56 Product discharge port 57 Product discharge rod 58 Product discharge unit 59 Raw material supply port 60 Raw material supply control unit 61 Expansive drying processing device 62 Transfer perforated plate 63a Upper machine frame 63b Lower machine casing 64 Perforated plate 65 Rice grain transfer path 66 Rice grain supply port 67 Rice grain discharge port 68 Spring 69 Base stand 70 Hot air generation supply device 70a Burner section 70b Blower fan 70c Hot air transfer pipe 70d Hot air supply port 71 Exhaust port 72 Net drying Device 73 Hot air generating and supplying device 73a Burner unit 73b Blower fan 73c Hot air transfer pipe

Claims (11)

A pre-pressurized steaming step of steaming raw rice grains of split rice or brown rice with pressurized steam;
A quantitative hydration step of quantitatively hydrating rice grains discharged from the pre-pressurized steaming step;
Finished pressurized steaming step of steaming the rice grains discharged from the quantitative water adding step with pressurized steam;
A finishing rice milling process for finishing and polishing the rice grains discharged from the finishing pressure steaming process;
A quantitative hydration step of quantitatively hydrating rice grains discharged from the finished rice polishing step;
A swollen drying step of drying the rice grains discharged from the quantitative water addition step by heating;
A finish drying step of heating and drying rice grains discharged from the expansion drying step;
A method for producing an instant rice, comprising:   2. The method for producing instant rice according to claim 1, wherein the expansion drying step is performed such that the moisture content of the rice grains is within a range of 20% to 25% at a temperature of 150 ° C. to 250 ° C. 3.   2. The method for producing instant rice according to claim 1, wherein the finish drying step is performed such that the moisture content of the rice grains is within a range of 12% or less at a temperature of 100 ° C. or less.   The method for producing instant rice according to claim 1, wherein the quantitative hydration step hydrates the rice grains at a rate of 20% / h to 80% / h.   The said pre-pressurization cooking process is a manufacturing method of the instant rice of Claim 1 performed for 2 to 5 minutes by the pressurization state of 0.001 MPa-0.3 MPa.   The method for producing instant rice according to claim 1, wherein the quantitative hydration step hydrates the rice grains to a moisture content of 20% to 28%.   The method for producing instant rice according to claim 1, wherein the finish pressure steaming step is performed in a pressurized state of 0.1 MPa to 0.3 MPa for 2 minutes to 10 minutes.   The manufacturing method of the instant rice of Claim 1 which provides the normal pressure steaming process which heats a rice grain with a normal pressure steam in the pre-process of the said prepressurization steaming process and / or a finishing pressurization steaming process.   The manufacturing method of the instant rice of Claim 1 provided with the moisture refining process of refining the moisture content between each rice grain in the post process of the said quantitative water addition process.   The manufacturing method of the instant rice of Claim 1 which provides the cooling process which reduces the heat | fever of the at least surface of the rice grain discharged | emitted from the finishing pressure cooking process in the post process of the said finishing pressure cooking process.   The instant rice manufactured by the manufacturing method of the instant rice in any one of the said Claims 1-11.

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