JP2011000056A - Method for producing parboiled rice and parboiled rice produced by the production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing parboiled rice, which shortens a time required for wetting treatment without causing cracks in rice grain in a wetting treatment step.SOLUTION: In the method for producing parboiled rice, since a pregelatinized layer is formed on the surface of raw material unpolished rice by a prepressurization steaming treatment and then wetting treatment is carried out, even if a wetting rate is high in the wetting treatment, the unpolished rice absorbs water at a high speed up to a target water content without causing cracks because the surface of unpolished rice is provided with toughness by the pregelatinized layer. Consequently, in the water absorption treatment, since unpolished rice rapidly absorbs water (high-speed wetting) without aggravating unpolished rice qualities by cracks, etc., a wetting treatment time is shortened and a production time of parboiled rice is made short.

Description

  TECHNICAL FIELD The present invention relates to a production method mainly using long grain seeds and medium grain seed brown rice raw materials as perboiled rice, and perboiled rice produced by the production method.

  Conventionally, there are dry cooked rice foods that can be returned to the state of cooked rice in a short time by adding water or hot water. One type of dry rice food is parboiled rice. This parboiled rice is eaten not only in Asia, such as India and Pakistan, but also in the United States and Europe. The parboiled rice is made by steaming the raw rice (rice) as it is, then drying, kneading, and milling the rice in sequence. When eating, boil it for 10 minutes in hot water. To be eaten. The parboiled rice has a flavor of rice husk odor because the raw rice husk is steamed as it is in the production process, so that the smell of rice husk penetrates into the endosperm.

  In recent years, consumers' preference for the taste of the parboiled rice has diversified, and an increasing number of consumers dislike the flavor of rice husk odor attached to the parboiled rice. For this reason, the development of the parboiled rice which does not have a rice husk smell is performed, for example, the manufacturing method of the parboiled rice described in patent document 1 and patent document 2 came to be performed. In the production methods described in Patent Documents 1 and 2, the raw material is brown rice, the brown rice is subjected to a mashing treatment, then subjected to water treatment by spraying or humidification, etc., and then subjected to moisture conditioning. Parboiled rice (product) is produced by converting the inside of the rice grains into α by pressure steaming and then subjecting it to cooling, finishing, and drying. According to this production method, since raw brown rice is cooked, parboiled rice without the flavor of rice husk odor can be obtained.

JP 2008-220221 A JP 2009-27950

However, in the above production method, when the brown rice is hydrated, if the rate of hydration is increased, cracks occur on the surface of the rice grains. Therefore, the rate of hydration is moderate (slow) to prevent the occurrence of cracks associated with hydration. (Hydrolysis rate: 0.5% / h to 0.8% / h). For this reason, there was a problem that it took a long time for the hydration process in the hydration process.
Therefore, in view of the above problems, the present invention has a technical problem to provide a method for producing a parboiled rice that can reduce the time required for the water treatment without causing cracks in the rice grains in the step of the water treatment. Is.

The method for producing the parboiled rice according to the present invention is as follows.
A pre-pressurized steaming process in which raw brown rice is steamed with pressurized steam;
A hydration step of hydrating the rice grains discharged from the pre-pressure steaming step;
A moisture refining process for refining the moisture of the rice grains discharged from the hydration process;
Finished pressure steaming step of steaming the rice grains discharged from the moisture conditioning step with pressurized steam;
A drying step of drying the rice grains discharged from the finish pressure steaming step;
Finishing rice milling process for finishing rice grains discharged from the drying process;
The technical means of providing these in order is taken.
As mentioned above, since the pre-pressurized steaming process was performed to form the pregelatinized layer on the surface of the raw brown rice, the hydrotreatment was performed, so the surface of the brown rice was toughened by the pregelatinized layer, so the rate of water addition Even if it is rapid, water can be absorbed up to the target moisture content without causing cracks, and the hydration time can be shortened.

  In the hydration step, the rice grains may be hydrated at a hydration rate of 20% / h to 80% / h.

  The pre-pressure steaming step may be performed in a pressurized state of 0.1 MPa to 0.3 MPa for 120 seconds to 300 seconds.

  In the hydration step, the rice grains may be hydrated to a moisture content of 20% to 28%.

  The finish pressure steaming step may be performed for 120 seconds to 600 seconds in a pressurized state of 0.1 MPa to 0.3 MPa.

  It is good to provide 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.

  It is preferable to provide a tempering step after the hydration step.

  It is good to provide the cooling process which reduces the heat | fever of the surface of at least the surface of the rice grain discharged | emitted from the finishing pressure cooking process in the post process of the said finishing pressure cooking process.

  According to the method for producing parboiled rice of the present invention, the raw brown rice is subjected to a pre-pressurized steaming treatment so that the hydrotreating is performed in a state in which the pregelatinized layer is formed on the surface of the raw brown rice. However, since the brown rice surface is provided with toughness due to the α-ized layer, cracks do not occur and water can be absorbed at a high speed to the target moisture content. This allows rapid water absorption (high-speed water addition) without deteriorating the quality of brown rice due to cracks, etc., during the hydration process, so there is no need for slow hydration, thus shortening the hydration time. And the manufacturing time of parboiled rice can be shortened. In addition, since the formation of the α-ized layer on the surface of the raw brown rice is processed by pressure steaming rather than atmospheric steaming, the rice grain surface is uniform without cracking the brown rice surface by pressure steaming applied from the entire circumference It is possible to make a suitable α. Therefore, the parboiled rice completed through this post-process becomes a product with good appearance.

The manufacturing flow in the manufacturing method of the parboiled 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 circulation type grain dryer in this invention is shown. The longitudinal cross-sectional view of the vertical grinding-type rice mill in this invention is shown.

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

  The raw material is brown rice, and long grain seeds or medium grain seeds are used.

Step 1 (atmospheric pressure cooking process):
In this step, the raw brown rice is prepared in the next step and is cooked at normal pressure and heated (preliminary heating). 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 provided horizontally in the upper stage is disposed in a downwardly inclined manner from the one end supply side to the other end discharge side so that the raw material flows 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 material flows down, and the one end supply side includes the lower transfer pipe. The discharge side of 6 is inserted, and the discharge side of the other end is communicated with a 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 so that the raw material (brown rice) is not cracked. Is set as appropriate within a range of 300 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. The raw material (brown rice) is supplied to one end supply side of the rotary drum 3 through the feed valve 5 a and the raw material supply pipe 5 while rotating the rotary drums 3 and 4.

  The raw material supplied into the rotary drum 3 is covered with the steam (saturated water vapor) at normal pressure, whereby the air between the raw material grains is expelled by the steam and the steam fills the intergranular space. The raw material is heated. At this time, the raw material flows down toward the other end discharge side while being stirred by the rotation of the rotary drum 3. The intergranular air 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 rotating drum 4, the raw material is heated while being stirred and transferred in the same manner as the operation of the rotating drum 3, and discharged from the other end discharge side. The normal pressure cooking time until brown rice is charged and discharged is preferably within about 1 minute so as not to cause cracks in the rice grains. In this way, the raw material is preliminarily heat-treated at a temperature of about 100 ° C. without causing shell cracks, while air is filled with saturated steam between the rice grains in preparation for the subsequent pressure steaming step. The process of excluding is performed. The raw material discharged from the other end discharge side of the rotating drum 4 is sent to the pre-pressurized steaming step (step 2) through the lower transfer pipe 7. Since steam is used in the normal pressure steaming process, the amount of water used is small and the amount of drainage from the discharge part 2b is 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 production efficiency in time and has a good quality product (brown rice parboil). ) 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 material discharged from the previous step normal pressure steaming step (atmospheric pressure steaming device 1) is α. 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 of the inclined chute tube 15a communicates with the discharge side of the lower transfer tube 7, and the rice grains (brown rice) discharged from the previous step 1 (atmospheric pressure cooking step) are subjected to the step 2 (Pre-pressurized steaming process) has been accepted.

  A plurality of valves are incorporated 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 raw material supply from Step 1 is received. The plurality of valves are arranged in the lower transfer pipe 7 in order from the top, the shock absorbing damper 7a for absorbing the drop impact of the raw material, the upper butterfly valve 37b, the lower butterfly valve 37c, and the raw material 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 raw material 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 and the gap 7f are closed. Release the pressure (pressurized heating steam). Next, the upper butterfly valve 7b is opened, and the raw material is 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 raw material has accumulated in the gap 7f, the air vent valve 7e is closed and the upper butterfly valve 7b is closed, and then the lower butterfly valve 7c is opened. The raw material falls by its own weight and is supplied to the pressurized steaming device 14 (in the inclined chute tube 15a) via the loosening plate 7b. By repeating the above sequence, the raw materials for one lot are sequentially supplied into the pressure cooking apparatus 14.

  A lower transfer pipe 18 for discharging the brown rice whose surface of the rice grain is pregelatinized in the pressurized steaming device 14 to the outside of the machine wall 15 is disposed on the conveying 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 brown rice that has been subjected to the pregelatinization treatment is discharged from the pressurized steaming device 14 via 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. Then, the upper butterfly valve 18b is opened, and the flow rate of supplying the brown rice to be discharged into the gap 18e by adjusting the opening of the shock absorbing damper 18a is adjusted. When a predetermined amount of the brown rice is 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 brown rice is dropped and discharged by its 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 0.1 MPa to 0.3 MPa. Adjust so that it is an arbitrary set value. Thus, the temperature inside the machine wall 15 when the pressure inside the machine wall 15 becomes 0.1 MPa to 0.3 MPa is in a state of about 120 ° C. to about 145 ° C. Next, the brown rice 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 brown rice is preferably in the range of 120 seconds to 300 seconds, 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 brown rice is subjected to pressure steaming treatment for 120 seconds to 300 seconds in a pressurized state of 0.1 MPa to 0.3 MPa (temperature: about 120 ° C. to about 145 ° C.), whereby the surface layer is formed. It is made alpha (about 10% to 20%), and then discharged from the lower transfer pipe 18. The degree of alpha conversion of the brown rice 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 small.

  In this way, the merit of steaming brown rice under pressure is that even if the grains of brown rice are in contact with each other, each steamed rice is evenly distributed from the entire circumference by saturated steam that is smoothly filled between the grains by the pressure. Since it can be steamed under pressure, it is in the point that the surface layer of each brown rice becomes uniform and the variation is reduced. In this point, in the hydration step (step 3), which is a subsequent step, there is an effect that no hydration unevenness for each grain of brown rice or hydration (moisture content) unevenness in one grain of brown rice occurs, and a higher quality brown rice parboil is produced. Effective in terms.

Step 3 (hydration process) and step 4 (tempering process):
In this process, there are a hydration process and a tempering process in which brown rice obtained by pre-gelatinizing the surface layer discharged from the pre-pressurized steaming process (pressurized steaming apparatus 14) is hydrolyzed and tempered (tempered) to a predetermined moisture value. FIG. 3 shows a hydration apparatus 20 used in the hydration process and a tempering apparatus 25 used in the tempering process.

Configuration of the water adding device 20:
The 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 water adding device 20 includes a supply tank 21 that stores brown rice whose surface layer is pregelatinized 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). 22 is connected to the raw material supply line 23. 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 spraying water for hydrating brown rice in the form of a shower is provided inside the supply pipe 23, and an umbrella-shaped rice grain flow restriction is provided above the 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 unit 26, and the rotary valve 26b is a reflux unit for returning the unpolished brown rice discharged from the rotary valve 26b into the tank unit 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 brown rice after hydration, and the sample collection means 28 has a known grain moisture meter 29. Connect. Thereby, the moisture content of the brown rice passing through the reflux path is measured as needed.

  Further, a flow path switching valve 30 is provided on the discharge side of the recirculation part 27, and the flow path 30a on the recirculation side to the tank part 26 and the water adding device 20 or the next step (atmospheric pressure cooking step / step 5). It is possible to switch to the flow path 30b on the side toward the front. 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 (hydration step) will be described.
When the brown rice subjected to the surface layer α-treatment in the previous process (Step 2 <preliminary pressure steaming process>) is sequentially fed from the supply tank 21 by the rotation of the rotary valve 22 and flows 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 brown rice supplied to the stirring cylinder 24a is subjected to a rotating action of the stirring means 24d comprising the stirring transfer part shaft 24b and the stirring transfer blade 24c, is transferred while being stirred with shower water, and is discharged from the discharge part 24e. . In this way, the brown rice is agitated and transported in the stirring cylinder 24a, and since the surface layer is uniformly alpha-treated, the surface layer is provided with 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 brown rice is set to a level that does not generate surplus water (drainage) as much as possible, and the amount of water absorbed into brown rice becomes faster, and the target value for water addition (target) The hydration time from 20% to 28% of the water content can be shortened. At that time, since the surface layer of the brown rice is uniformly pregelatinized, uniform water can be added from the whole surface of the brown rice to the inside without causing cracks on the surface of the brown rice.

  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. It should be noted that the higher the surface layer α-ized degree of brown rice is, the closer the acceleration rate is to 80% / h, and vice versa. As described above, the adjustment of the surface α-degree of brown rice is performed in Step 2 (preliminary pressure steaming step). In addition, in the hydration process, the present invention simplifies the production equipment that does not require wastewater treatment equipment by adjusting the amount of hydration added to and mixed with brown rice so that excess water is not discharged as much as possible. It also has the effect of reducing capital investment costs.

The operation of step 4 (tempering step) will be described.
In this step 4, one lot of brown rice hydrated in the previous process (step 3 <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 brown rice is completed, the brown rice in the tank 26 is fed from the bottom one by one by driving the rotary valve 26b and the reflux unit 27 to be conditioned and conditioned in the tank 26. Is done. During this circulation, the sampled browning rice sample after hydration is collected by the sample collecting means 28 and sent to the grain moisture meter 29 to measure the moisture content of the brown rice sample. When the measured moisture content is lower than the target moisture content described later, the brown rice is recirculated to the hydration device 20 through the flow path switching valves 30 and 31 and rehydrated. After that, it is stored in the tempering device 25 and tempered again to bring it close to the target moisture content and to reduce the variation between rice grains.

  In the tempering step, when the water content of the hydrated brown rice is in the range of 20% to 28%, the variation between the rice grains is made uniform so as to obtain an arbitrarily determined target water content. The time required for the tempering step is appropriately set within a range of about 30 minutes to 120 minutes. At this time, the temperature in the tank 26 is preferably in the range of 50 ° C to 50 ° C. In addition, since the nutrient components such as minerals contained in the cocoon layer and germ of brown rice are transferred to the endosperm portion by the tempering step, the nutrients are retained in the rice grains even if the brown rice is finally refined into a product.

Step 5 (normal pressure cooking process):
This step is a normal pressure steaming step of steaming and heating (preheating) brown rice 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 product (brown rice parboil).

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 brown rice discharged from the tempering process of the previous process is 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 brown rice again to advance the brown rice. The specific action of step 6 is to supply the brown rice preheated in step 5 (atmospheric pressure cooking process) to the atmospheric pressure steaming device 14 and to perform the alpha conversion 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 and set so as to be an arbitrarily set value within the range of 120 seconds to 600 seconds. Brown rice is subjected to pressurized steaming action from the whole surface direction of the rice grain for a predetermined time, while shortening the time to warm brown rice by pressurizing brown rice preheated under such pressure cooking conditions As a result, pregelatinization proceeds. By the pressure steaming action of Step 6, the degree of alpha conversion of the brown rice becomes about 80% to 90%. 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) of the surface of the brown rice that has been subjected to the pregelatinization process in the previous process, and facilitating the drying process of the next 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. On one upper end of the machine wall 33, a supply unit 35 for supplying the brown rice discharged from the previous process (finished and pre-gelatinized) onto the belt conveyor 34 is disposed. In addition, a discharge portion 36 for discharging the cooled brown rice from the conveyance end portion on the belt conveyor 34 is disposed at the other lower end portion 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 brown rice that has been subjected to the finish steaming process (finished α-formation process) in the preceding process is sequentially supplied from the supply unit 35 to the transport start end side of the transport endless belt 34a. While the brown rice supplied on the transport endless belt 34a is 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 brown rice has a moisture content in the range of about 17% to 25%.

Step 8 (drying process):
In this drying step, the cooled brown rice discharged from the previous step is dried to a moisture content of 13% or less. In the main drying step, for example, the circulation type grain drying device 42 shown in FIG. 5 may be used. The circulating grain drying device 42 may be a known one described in, for example, Japanese Patent Publication No. 8-25134. The circulation type grain drying device 42 includes a dryer main body 42a in which a storage unit (tempering unit) 43, a drying unit 44, and a discharge unit 45 are sequentially stacked, and an elevator installed on the side of the dryer main unit 42a. 46.

  The drying unit 44 includes a burner 47 for generating hot air, a hot air drum 48 to which the hot air is supplied, and a perforated plate at an arbitrary interval, and the hot air is passed to the grains flowing through the gap on the left and right sides, respectively. The arranged grain downflow layers 49, 49, and left and right exhaust wind tunnels 50, 50 for exhausting the hot air passed through the grain downflow layers 49, 49 (between grains) from the hot wind tunnel 48 to the outside of the machine, And an exhaust fan (not shown) that communicates with the exhaust cylinders 50 and 50 to suck out the hot air and exhaust it outside the apparatus.

  The discharge part 45 includes a feeding valve 51 disposed below the grain flow lower layers 49, 49, a funnel-shaped grain collecting board 52 provided below the feeding valve 51, and the grain collecting board The lower conveying screw 53 is arranged at the lower part of the conveying unit 52 and conveys the grain to the conveying start end side of the elevator 46.

  The elevator 46 has pulleys 54 and 54 disposed in an upper portion and a lower portion in a machine frame 46a, and an endless bucket in which a plurality of buckets 55 are attached to the pulleys 54 and 54. Belt 55a. One of the pulleys 54 and 54 is connected to a motor (not shown) to become a driving side, and the bucket belt 55a is transferred in the vertical direction. The lower part of the machine frame 46a communicates with the conveyance end side of the lower conveyance screw 53, and the upper part of the machine frame 46a communicates with the conveyance start end side of the upper conveyance unit 56 described later. A grain moisture meter 46b is attached to the side of the machine frame 46a so that the moisture content of the grain being dried can be automatically measured. The upper transport unit 56 is disposed above the storage unit 43 and includes an upper transport screw 57 and a scattering plate 58 facing the storage unit 43 at a position on the transport end side of the upper transport screw 57. It is. In addition, an opening / closing door 44a is provided on the machine wall on one side of the exhaust wind tunnels 50, 50 for inserting and supplying brown rice discharged from the previous cooling process, which is an object to be dried.

The effect | action of this drying process (step 8) is demonstrated.
First, the open / close door 44a is opened, and one lot of brown rice (moisture content: around 18%) discharged from the previous process (cooling process) is sequentially put and supplied. The supplied brown rice is conveyed and accumulated in the storage part 43 via the lower conveying screw 53, the elevator 46 and the upper conveying part 56 (the above is the tension operation). When the stretching operation is completed, the door 44a is closed and the drying operation is started.

  When the drying operation is started, the feeding valve 51, the exhaust fan, the elevator 46, the burner 47, etc. are driven, and the hot air generated in the burner 47 by the suction action of the exhaust fan is passed through the grain substreams 49, 49. Ventilate brown rice flowing down. The feeding valve 51 is intermittently rotated so that brown rice is sequentially fed from the lower part of the grain lower layer 49, 49. The fed brown rice is stored via the lower conveying screw 53, the elevator 46 and the upper conveying unit 56. It returns to the part 43 and is tempered in the storage part 43. In this way, the brown rice is dried evenly while circulating hot air and tempering while circulating in the machine. Then, when the measured moisture content of the brown rice measured by the grain moisture meter 46b falls to, for example, 13%, the drying operation is terminated and the discharging operation is performed to discharge the brown rice to the outside. Thus, the brown rice dried to 13% can be stored at room temperature.

Step 9 (finishing and polishing process):
In this finishing rice polishing process, dried brown rice discharged from the previous process is finished and polished. In this finishing rice milling process, for example, a known vertical grinding-type rice mill 59 shown in FIG. 6 is used. The configuration of the vertical grinding rice mill 59 includes a milling roll 62 formed by axially attaching a grindstone roll 61 to a rotary spindle 60, and a gap (milling chamber) 63 at a predetermined interval in the outer peripheral direction of the milling roll 62. The disposed perforated screen 66 and the removal housing chamber 67 disposed in the outer peripheral direction of the perforated screen 66 are configured. The rotating main shaft 60 is pivotally supported by bearings 60a arranged at arbitrary positions above and below the rotating main shaft 60, and the lower end portion is connected to the output side of the motor 71 via the pulley 68 and the power transmission belt 69 that are attached to the shaft. It connects with the pulley 70 which becomes, and is comprised rotatably by this. Further, a product discharge section 75 is formed at the lower end of the scouring chamber 63, and the product discharge section 75 includes a resistance lid 72, a product discharge port 73 and a product discharge basket 74.

  On the other hand, the upper end portion of the semen chamber 63 communicates with a raw material supply port 76 disposed further above. The raw material supply port 76 is provided with a raw material supply adjusting unit 77. In addition, the lower end part of the said debris storage chamber 67 is connected with the exhaust fan 64 via the pipe line 65, and sucks and discharges a soot outside the apparatus.

The effect | action of this finishing rice polishing process is demonstrated.
In the final polishing process, first, the motor 71 of the vertical grinding-type rice mill 59 is started to rotate, the grindstone roll 61 is rotated, the resistance of the product discharger 75 is adjusted, and the like before the operation is started. Make settings. Thereafter, when brown rice (about 13% dried) discharged from the previous process is supplied from the raw material supply port 76, the brown rice is ground by contact with the grindstone roll 61 and the like while flowing down the scouring chamber 63 from above. The bran layer on the surface of the rice grains is gradually removed by the action or the like to become polished rice, which is discharged from the product discharge portion 75 as a product of parboiled rice.

Step 10 (wet grinding process):
This wet polishing process is a process that may be performed as necessary when it is desired to further improve the appearance quality (improvement of gloss) of the polished rice (parboiled rice) discharged from the previous process. The wet polishing process uses a well-known wet polishing apparatus, adds a small amount of sprayed water to the polished rice (product), and rubs the polished rice together to make the surface glossy. It is a process of taking out. Since the wet polishing apparatus is well known, the description of the specific configuration is omitted.

Variations of the embodiment:
In addition, the parboiled rice completed in the above embodiment is eaten in hot water for about 10 minutes when eating, as described above. On the other hand, as a modification, instant rice processing may be performed by using the brown rice after the above-mentioned cooling process, and instant processing may be performed. In the instant rice processing, the brown rice (high moisture) after the above-mentioned cooling process is subjected to the same rice polishing treatment as in Step 9 (finishing rice polishing process), and the resulting polished rice is further water-absorbed to a moisture content of about 40%. For example, it is a process of steaming this to further advance the gelatinization, and then rapidly drying. The finished instant rice does not need to be boiled, and can be restored to cooked rice simply by pouring hot water.

  When manufacturing parboiled rice that is eaten in Asia, such as India and Pakistan, as well as in the United States and Europe, production time can be shortened and production efficiency can be improved. It is useful as a production facility for parboiled rice that does not require 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 Circulating Grain Drying Device 42a Dryer Main Body 43 Storage Unit 44 Drying Unit 45 Discharge Unit 46 Elevator 46a Machine Frame 46b Grain moisture meter 47 Burner 48 Hot air drum 9 Grain downstream layer 50 Wind exhaust drum 51 Feeding valve 52 Grain collecting plate 53 Lower conveying screw 54 Pulley 55 Bucket 55a Bucket belt 56 Upper conveying portion 57 Upper conveying screw 58 Scatter plate 59 Vertical grinding rice mill 60 Rotating spindle 60a Bearing 61 Grinding wheel roll 62 Whitening roll 63 Graining chamber 64 Exhaust fan 65 Pulley 65 Pipe line 66 Porous screen 67 Removal chamber 68 Pulley 69 Power transmission belt 70 Pulley 71 Motor 72 Resistance lid 73 Product discharge port 75 Product discharge rod 75 Product discharge part 76 Raw material supply port 77 Raw material supply control section

Claims (9)

A pre-pressurized steaming process in which raw brown rice is steamed with pressurized steam;
A hydration step of hydrating the rice grains discharged from the pre-pressure steaming step;
A moisture refining process for refining the moisture of the rice grains discharged from the hydration process;
Finished pressure steaming step of steaming the rice grains discharged from the moisture conditioning step with pressurized steam;
A drying step of drying the rice grains discharged from the finish pressure steaming step;
Finishing rice milling process for finishing rice grains discharged from the drying process;
A method for producing parboiled rice, wherein   The method for producing parboiled rice according to claim 1, wherein the hydration step hydrates the rice grains at a hydration rate of 20% / h to 80% / h.   The said pre-pressure steaming process is a manufacturing method of the parboiled rice of Claim 1 or Claim 2 performed for 120 second-300 second in the pressurization state of 0.1 MPa-0.3 MPa.   The said hydration process is a manufacturing method of the parboiled rice in any one of the said Claim 1 thru | or 3 which hydrates rice grain to 20%-28% moisture content.   The method for producing parboiled rice according to any one of claims 1 to 4, wherein the finish pressure steaming step is performed in a pressurized state of 0.1 MPa to 0.3 MPa for 120 seconds to 600 seconds.   The pre-pressurizing steaming step and / or the finishing pressurizing steaming step are provided with a normal pressure steaming step of heating rice grains with normal pressure steam, according to any one of claims 1 to 5. A method for producing parboiled rice.   The manufacturing method of the parboiled rice in any one of the said Claims 1 thru | or 6 provided with the tempering process in the post process of the said water addition process.   The parboil according to any one of claims 1 to 7, wherein a cooling step for reducing the heat of at least the surface of the rice grains discharged from the finishing pressure cooking step is provided in a step subsequent to the finishing pressure cooking step. Rice manufacturing method.   A parboiled rice produced by the method for producing a parboiled rice according to any one of claims 1 to 8.

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