WO2022239366A1

WO2022239366A1 - Method and device for producing pregelatinized rice

Info

Publication number: WO2022239366A1
Application number: PCT/JP2022/007792
Authority: WO
Inventors: 光輝瀧本
Original assignee: 株式会社サタケ
Priority date: 2021-05-14
Filing date: 2022-02-25
Publication date: 2022-11-17
Also published as: JP2022175550A

Abstract

This method for producing pregelatinized rice includes a pressurizing and steaming step for pressurizing and steaming a starting rice material 1. This method for producing pregelatinized rice also includes a cooking step for steam-cooking the rice material having been pressurized and steamed in the pressurizing and steaming step. This method for producing pregelatinized rice also includes a swelling step for swelling the rice material, which has been cooked in the cooking step, by sprinkling water. This method for producing pregelatinized rice also includes a drying step for drying the rice material having been swollen in the swelling step.

Description

Pregelatinized rice production method and pregelatinized rice production apparatus

This disclosure relates to technology for producing pregelatinized rice.

Pregelatinized rice, for example, takes less time to cook than regular rice, and can be easily cooked without the need for washing and soaking.

Japanese Patent No. 6784165 discloses a technique for producing quick-return instant rice using raw rice through the steps of pressure steaming, rice cooking, swelling soaking, and drying.

In addition, Japanese Patent Application Laid-Open No. 6614436 discloses a technique of cooking rice with enzyme-added water and having multiple drying steps.

Furthermore, Japanese Patent Application Laid-Open No. 2019-33719 discloses a technique for swelling and soaking rice while water is transported in a pipe during the swelling and soaking step.

In the methods described in Japanese Patent No. 6784165 and Japanese Patent Application Laid-Open No. 2019-33719, soaking the cooked rice causes the rice to absorb excessive water, resulting in a considerable degree of broken rice, leading to a decrease in the rate of non-defective products. can connect.

In addition, the method described in Japanese Patent Application Laid-Open No. 6614436 requires the addition of enzymes in the rice cooking step, which leads to an increase in man-hours.

Furthermore, in the method described in JP-A-2019-33719, piping is required in the swelling and immersion step, so at least a step for pipe processing is also required.

The present disclosure has been made in view of the above circumstances, and aims to provide a method for producing pregelatinized rice that can suppress the occurrence of broken rice and make it edible more efficiently. .

In order to achieve the above object, the method for producing pregelatinized rice according to the present disclosure includes a pressure steaming step of pressurizing and steaming rice. Also, the method for producing pregelatinized rice includes a rice cooking step of steam-cooking the rice pressurized and steamed in the pressure steaming step. Moreover, the method for producing pregelatinized rice includes a swelling step of swelling the rice cooked in the rice cooking step by sprinkling water. Moreover, the method for producing pregelatinized rice includes a drying step of drying the rice swollen by the swelling step.

According to the method for producing pregelatinized rice according to the present disclosure, it is possible to suppress the occurrence of broken rice and more efficiently make it edible.

Simplified flow diagram of the method for producing pregelatinized rice according to the present embodiment Schematic diagram showing an apparatus for realizing the method for producing pregelatinized rice according to the present embodiment. A partial schematic diagram showing a part of the surface of pregelatinized rice produced using the method for producing pregelatinized rice according to the present embodiment. FIG. 3A is a partial schematic diagram showing a portion of pregelatinized rice produced using a conventional method for producing pregelatinized rice, on the same scale as FIG. 3A. FIG. 10 is a diagram showing a partial modification of the apparatus that realizes the method for producing pregelatinized rice according to the present embodiment, and is a partial outline showing a form in which a plurality of triangular structures are arranged above the second conveyor. Plan view FIG. 10 is a diagram showing a partial modification of the apparatus that realizes the method for producing pregelatinized rice according to the present embodiment, and is a partial outline showing a form in which a plurality of triangular structures are arranged above the second conveyor. right side view FIG. 10 is a diagram showing a partial modification of the apparatus for realizing the method for producing pregelatinized rice according to the present embodiment, and is a partial schematic plan view showing a mode in which a regulating plate is arranged above the second conveyor. FIG. 10 is a diagram showing a partial modification of the apparatus for realizing the method for producing pregelatinized rice according to the present embodiment, and is a partial schematic right side view showing a mode in which a regulating plate is arranged above the second conveyor. FIG. 10 is a view showing a partial modification of the apparatus for realizing the method for producing pregelatinized rice according to the present embodiment, in which a plurality of triangular structures and a regulation plate are arranged above the second conveyor. Partial schematic plan view to represent FIG. 10 is a view showing a partial modification of the apparatus for realizing the method for producing pregelatinized rice according to the present embodiment, in which a plurality of triangular structures and a regulation plate are arranged above the second conveyor. Partial schematic right side view

The method for producing pregelatinized rice according to the present disclosure will be described below with reference to the drawings.

First, with reference to FIGS. 1 and 2, a method for producing the above pregelatinized rice will be described. The method for producing pregelatinized rice according to the present embodiment includes a pressure-steaming step (step S10) of pressurizing and steaming the rice, and a rice-cooking step of cooking the rice pressurized and steamed by the pressure-steaming step with steam. (S20), a swelling step (S30) of swelling the rice cooked in the rice cooking step by sprinkling water, and a drying step (S40) of drying the swollen rice in the swelling step. Pregelatinized rice is rice in which a plurality of cracks are formed on the surface of rice grains, and is produced by rapidly drying cooked rice.

First, prepare raw rice 1 to be processed. A desired amount of raw rice 1 is prepared and processed into pregelatinized rice using a pregelatinized rice manufacturing apparatus 10 .

(1) Raw material rice In the present invention, polished rice of Japonica rice (short-grain variety) is used as the raw material rice 1 . The whiteness of the milled rice is 38% or less, and the moisture content is 10-20% in one embodiment, 10-16% in another embodiment, and 10-14% in yet another embodiment. In this specification, the rice obtained by adding 15% or less by weight of water or a sticky substance for removing the bran to the polished rice, polishing the surface of the polished rice, and removing the bran remaining on the surface of the polished rice is treated as rinse-free rice. The whiteness is a value measured by receiving reflected light from rice grains, where 0 is the dark state and 100 is the whiteness of barium sulfate.

(2) Pressure Steaming Step In the pressure steaming step (S10), the surfaces of the rice grains are gelatinized. First, the raw material rice 1 is put into the pregelatinized rice manufacturing apparatus 10 from the inlet 11 of the pregelatinized rice manufacturing apparatus 10 , and the raw material rice 1 is conveyed onto the first conveyor 12 . The first conveyor 12 that conveys the raw material rice 1 is provided with a large number of holes so that the raw material rice 1 can be conveyed and steam can pass through.

Next, the raw material rice 1 conveyed on the first conveyor 12 is steamed with pressurized heated steam at 100 to 130° C. under a pressure of 0.01 to 0.1 MPa (gauge pressure) to obtain a 0.5 Treat for ~2 minutes.

The raw rice 1 is conveyed by the first conveyor 12 for subsequent processing while being pressurized and steamed.

In this way, by rapidly pressurizing the raw rice 1 at a high temperature, a gelatinized film is formed on the surface of the raw rice 1 with a thickness of 0.1 to 0.2 mm. can be prevented.

(3) Rice Cooking Process The raw rice 1 that has been pre-cooked in the pressure steaming process is transported to a rice cooking unit in the same unit as the pressure steaming unit in which the pressure steaming process is performed, where the rice is cooked. applied. The raw material rice 1 conveyed to the rice cooking unit is cooked together with a predetermined amount of rice cooking water and one type of enzyme selected from amylase and protease added to the rice cooking water. Enzymes are added in an amount of 0.07 to 0.6% based on the weight of raw rice 1. The rice water is, in one embodiment, at an initial temperature of 35-40°C.

The rice cooking unit in which the rice cooking process is performed is provided above the first conveyor 12, and includes a nozzle 13 for injecting rice-cooking water, and a uniform or substantially uniform height (thickness) of the layer of raw rice 1 on the first conveyor 12. A stirring rod 14 for leveling and a heating steam ejection part 15 provided at the bottom of the first conveyor 12 are provided.

In the rice-cooking process, first, rice-cooking water added with one of amylase and protease is sprayed from the nozzle 13 toward the raw rice 1 which is leveled and conveyed by the stirring rod 14 on the first conveyor 12 . . In addition, the raw rice 1 moving on the first conveyor 12 is leveled by the stirring rod 14 . Heating steam of about 100 to 130° C. is jetted from the heating steam jetting section 15 toward the raw rice 1 moving on the first conveyor 12 through holes provided in the first conveyor 12 .

At this time, the heating steam (rice-cooking water) ejected from the heating steam ejection part 15 is ejected as steam having a temperature lower than the temperature applied in the pressure steaming process.

The time of this rice cooking process is 15 to 60 minutes from the time the raw rice 1 is conveyed to the rice cooking unit to the time it is carried out from the rice cooking unit in one embodiment, and is 20 to 40 minutes in another embodiment. .

By advancing the rice cooking process with heated steam in this way, it is no longer necessary to soak the raw material rice 1 before cooking, and it is possible to save labor and improve efficiency in the rice cooking process.

The water content per grain of raw rice 1 (cooked rice) cooked in the rice cooking process is 60% or more and 80% or less in one embodiment, and 70% or more and 75% or less in another embodiment. , and in still other embodiments, between 70% and 72%.

(4) Swelling Process The raw rice 1 cooked in the rice cooking process is conveyed to the swelling unit and subjected to swelling treatment. The swelling unit includes a second conveyor 16 that conveys the raw rice 1 conveyed from the rice cooking unit in the swelling unit, a water addition nozzle 17 that adds water to the raw rice 1 in the swelling unit, and the raw rice 1 on the second conveyor 16. A widening stirring screw 18 is provided.

The raw material rice 1 conveyed to the swelling unit is directed to the raw material rice 1 moving on the second conveyor 16, and water of 60 to 70° C. is added from the water addition nozzle 17 so that the flow rate is 0.5 to 4 L/min. Inject.

At this time, the raw rice 1 moving on the second conveyor 16 is spread to a desired layer thickness (thin layer) on the second conveyor 16 while leveling the raw rice 1 moving on the second conveyor 16 by the stirring screw 18 arranged on the upper part of the second conveyor 16. .

As a result, the water sprayed from the water addition nozzle 18 can be efficiently applied to the entire surface of the rice.

From this point of view, in one embodiment, a clearance of about 5 to 7 mm is provided between the stirring screw 18 and the second conveyor 16.

Thus, the water content per grain of raw rice 1 (swollen rice) swollen in the swelling step is 60% or more and 80% or less in one embodiment, and 70% or more and 75% or less in another embodiment, In still other embodiments, it is 73% or more and 75% or less.

In this way, the raw rice 1 (cooked rice) cooked in the rice cooking process is swollen by sprinkling water, forming cavities inside the rice grains, and the gelatinization of the raw rice 1 (cooked rice) is completed.

When the pregelatinized rice produced in this way is hydrated, it becomes possible to reach an edible state within 5 minutes.

In addition, it is possible to prevent excessive outflow of starch from the surface of rice, prevent the occurrence of cracks that lead to broken rice in the subsequent drying process, maintain or improve the yield rate, and maintain or improve the texture. It can also lead to improvements and be more likely to have a positive aesthetic impact.

Note that, in one embodiment, the swelling process time is 5 to 10 minutes from when raw rice 1 (cooked rice) is transported to the swelling unit until it is transported out of the swelling unit.

(5) Primary drying process The raw rice 1 (cooked rice) that has undergone the swelling process is repelled by the scattering pin 19, and a hot air drying mechanism, a superheated steam drying mechanism, and a microwave are used to evaporate moisture from the raw rice 1 (cooked rice). Equipped with a drying mechanism such as a drying mechanism, it is sequentially conveyed inside a drying unit formed by a primary drying unit and a secondary drying unit.

In the primary drying unit, the water content of raw rice 1 that has undergone the swelling process is rapidly evaporated at a relatively high temperature of 115-130°C for 20-30 minutes. As described above, the gelatinization of the raw material rice 1 is completed in the swelling process, but the gelatinization occurs again in the primary drying process, causing the raw material rice 1 to swell and the moisture content of the raw material rice 1 to be 20 to 25%. Become.

(6) Secondary drying process In the secondary drying process that follows the primary drying process, drying is performed at a relatively low temperature of 60 to 90°C for 50 to 60 minutes to reduce the moisture content of the raw rice 1 to 5%. Adjust to 10% or less.

As shown in FIG. 3A, the pregelatinized rice prepared according to the present embodiment has smaller pores appearing on a certain surface and a smaller pore area than the conventional pregelatinized rice shown in FIG. 3B. becomes.

Thus, by gently drying the rice, the water activity AW can be reduced to 0.45 or less, so the preservability of pregelatinized rice can be maintained or improved.

After completing the secondary drying process, the pregelatinized rice is de-bonded between rice grains in a single granulator (not shown) as necessary. Removed and commercialized.

<Example>
As raw material rice (polished rice), 300 g of "Haenuki" produced in Yamagata Prefecture in 2014 with a moisture content of 14% and a whiteness of 40% was prepared. At this time, the temperature in the test room was set to 25°C.

After washing the polished rice, we measured the water content of the polished rice and confirmed that the water content of the polished rice was 16% or less.

This polished rice was put into the inlet 11 of the pregelatinized rice manufacturing apparatus 10, and the polished rice was transported onto the first conveyor 12 inside. The milled rice moving on the first conveyor 12 was steamed with pressurized heated steam at 105° C. for 1 minute under a pressure of 0.02 MPa.

2 g (0.7%) of a liquid enzyme containing amylase and protease (Otsuka Pharmaceutical Co., Ltd. OS-60L) and 1 g (0.3%) of an emulsifier (Otsuka Pharmaceutical Co., Ltd. OS-77L) made of soybean-derived lecithin were added to water in advance. Each was added to prepare rice-cooking water. Next, after steaming, the raw rice 1 which is conveyed to the rice cooking unit by the first conveyor 12 and is moving on the first conveyor 12 while being leveled by the stirring rod 14 is sprayed with rice cooking water adjusted to 35° C. by the nozzle 13 . sprayed from In addition, heating steam at 100° C. was jetted from the heating steam ejection part 15 toward the raw material rice 1 moving on the first conveyor 12, and the rice was cooked for about 35 minutes, followed by steaming for 20 minutes. The water content of the raw rice 1 after steaming was about 70%, and the volume after cooking was about 1.5 times the volume of the raw rice before cooking.

The cooked raw material rice 1 was transported from the first conveyor 12 onto the second conveyor 16 and transported to the swelling unit. Next, while the raw rice 1 transported to the swelling unit was leveled by the stirring screw 18, water at 60° C. was sprayed from the water addition nozzle 17 toward the raw rice 1 for 6 minutes to swell it. When the water content of the swollen cooked rice was measured, the water content was 74%.

By flipping the swollen raw material rice 1 with the scattering pin 19, it was transported into the primary drying unit. In the primary drying unit, primary drying was first performed at a hot air temperature of 115° C. for 20 minutes.

After drying the raw rice 1 in the primary drying unit, the raw rice 1 was transported to the secondary drying unit and subjected to secondary drying with hot air at 80°C for 60 minutes to obtain pregelatinized rice.

The moisture content of the pregelatinized rice thus obtained was 7%. The pregelatinized rice obtained in this way had a weak binding state between rice grains and could be easily handled by hand.

When 85 cc of hot water at 95°C was added to 50 g of the prepared pregelatinized rice, it was restored to edible rice in 4 to 5 minutes and was eaten.

As a result, as shown in Table 1, the rice grains after reconstitution had little deterioration in appearance, moderate grain texture, and good taste and texture. In addition, the yield rate for polished rice was 90% or more, which was better than the yield rate (approximately 67%) of the conventional method.

The method for producing pregelatinized rice has been described above using the present embodiment as an example, but the method for producing pregelatinized rice is not limited to the above embodiment.

In the present embodiment, a configuration in which the pressure steaming unit and the rice cooking unit are included in the same unit has been described as an example. It is not limited to this. For example, the pressurized steaming unit and the rice cooking unit may be formed as separate units and connected together.

In addition, in the present embodiment, the raw material rice 1 moving on the second conveyor 16 is leveled and spread on the second conveyor 16 by the stirring screw 18 in the swelling step. If the rice 1 can be leveled and spread on the second conveyor 16, it is not limited to this.

For example, as shown in FIGS. 4A and 4B, a plurality of triangular prism-shaped partition structures 20 may be arranged above the second conveyor 16 . In this case, the movement direction of the raw material rice 1 moving on the second conveyor 16 and the arrangement direction of one vertex of each triangular prism-shaped partition structure 20 in plan view are opposed to each other, and the plan view (FIG. 4A) A plurality of triangular partition structures 20 are arranged so as to form Pascal's triangle at . The number of triangular partition structures 20 in this case can be represented by the following formula.

In order to level the raw rice 1 moving on the second conveyor 16 and spread it on the second conveyor 16, as shown in FIGS. 5A and 5B, the layer thickness of the raw rice 1 is set to a predetermined thickness. A stipulating plate 21 may be arranged on the upper part of the second conveyor 16 in order to allow the second conveyor 16 to move. In this case, the regulation plate 21 is arranged along the width direction of the second conveyor 16 .

Also, as shown in FIGS. 6A and 6B, a triangular partition structure 20 and a regulation plate 21 may be arranged on the second conveyor 16. In this case, in order to efficiently equalize the layer thickness of the raw material rice 1, the arrangement relationship between the triangular partition structure 20 and the regulation plate 21 is such that the triangular partition structure 20 is placed upstream of the second conveyor 16. , and a regulating plate 21 is arranged on the downstream side of the second conveyor 16 .

Thin layer forming structures such as the stirring screw 18, the triangular prism-shaped partition structure 20, and the regulating plate 21 allow water to be sprinkled while forming a thin layer of the raw rice 1, so that the water content of the raw rice 1 is made more uniform. becomes possible.

Also, the number of water addition nozzles 17 can be changed as appropriate.

1 Raw material rice, 10 Pregelatinized rice manufacturing device, 11 Input port, 12 First conveyor, 13 Nozzle, 14 Stirring rod, 15 Heating steam jet part, 16 Second conveyor, 17 Water addition nozzle, 18 Stirring screw, 19 Scattering application pin, 20 triangular prism-shaped partition structure, 21 regulation plate.

Claims

A pressure steaming step of pressurizing and steaming the raw rice,
a rice cooking step of cooking the raw rice, which has been pressurized and steamed in the pressure steaming step, with steam;
a swelling step of swelling the raw rice cooked in the rice cooking step by sprinkling water;
a drying step of drying the raw material rice swollen by the swelling step;
A method for producing pregelatinized rice.
The temperature in the pressure steaming step is equal to or higher than the temperature in the rice cooking step,
The method for producing pregelatinized rice according to claim 1.
The rice cooking in the rice cooking step is accompanied by conveying the raw rice, which has been pressurized and steamed in the pressure steaming step, by a belt conveyor.
The method for producing pregelatinized rice according to claim 1 or 2.
The watering in the swelling step is accompanied by conveying the raw rice cooked in the rice cooking step by a belt conveyor,
The method for producing pregelatinized rice according to any one of claims 1 to 3.
The moisture content contained in the raw rice cooked in the rice cooking step is 60% or more and 80% or less by the watering in the swelling step.
The method for producing pregelatinized rice according to any one of claims 1 to 4.
The swelling step includes a thin layer forming step of forming the raw rice cooked in the rice cooking step into a thin layer,
The method for producing pregelatinized rice according to any one of claims 1 to 5.
In the thin layer forming step, the raw rice is formed into a thin layer using a thin layer forming structure.
The method for producing pregelatinized rice according to claim 6.
a pressure steaming unit configured to pressurize and steam raw rice;
a rice cooking unit that uses steam to cook the raw rice that has been pressurized and steamed by the pressure steaming unit;
a swelling unit that swells the raw rice cooked by the rice cooking unit by sprinkling water;
a drying unit for drying the raw rice swollen by the swelling unit;
Pregelatinized rice manufacturing equipment.