KR102499223B1 - Manufacturing method of instant rice - Google Patents

Abstract

A method for producing instant rice that can be restored more quickly than before by promoting absorption and water penetration into the fine grains is a method of heating and pressurizing raw material rice to form an gelatinized layer on the surface layer of the fine grains, followed by cooking, followed by drying treatment, The pressurized heating treatment is a pressurized steaming treatment using saturated steam, which includes a step of rapidly reducing the pressure after maintaining a pressurized state for a certain period of time to generate minute cracks on the entire surface of the rice grains, and further immersing the rice rice after cooking to cause swelling It includes a swelling immersion process to

Description

Manufacturing method of instant rice {MANUFACTURING METHOD OF INSTANT RICE}

The present invention relates to instant rice reconstituted and eaten in hot water, and more particularly, to a method for producing instant rice that can be eaten in a shorter time than before without heating and cooking in a microwave oven or the like.

Conventionally, in a method for producing instant rice in which raw material rice is pressure-cooked to form a gelatinized layer (alpha layer) on the surface of fine grains, then cooked and dried, the α Formation of the sintering layer relatively prevents clumping during cooking and improves product yield, while the gelatinization layer inhibits absorption into the inside of the particulate during cooking, so swelling of the particulate does not proceed. In the subsequent drying process, expansion drying by high temperature is performed (refer to Japanese Unexamined Patent Publication No. 2013-51889). As a result, water absorption at the time of cooking is increased, and the outer appearance is improved by swelling convexly.

However, since the thing of Unexamined-Japanese-Patent No. 2013-51889 performs expansion drying by high temperature, it has a so-called "fried rice"-like texture, lacks particle feeling, and shows a slightly brownish color. In addition, due to the lack of water absorption by the gelatinization layer on the surface of the fine grains during cooking and the slow water permeation rate during restoration, the restoration time in the hot water was about 8 minutes.

In view of the above problems, an object of the present invention is to provide a method for producing instant rice that can be restored faster than before by promoting water absorption and water permeation during cooking.

In order to achieve the above object, a method for producing instant rice according to an embodiment of the present invention is a method of heating raw material rice under pressure to form an gelatinization layer on the surface layer of the rice grains, followed by cooking, and then drying. The treatment is a pressure cooking treatment with saturated steam, which includes a step of rapidly reducing the pressure after maintaining a pressurized state for a certain period of time to generate minute cracks on the entire surface of the rice grains, and further soaking the rice rice after cooking to cause swelling It is characterized in that a swelling dipping process is formed.

According to the instant rice manufacturing method of the embodiment of the present invention, in the pressurized heat treatment in the pre-cooking process, an gelatinization layer is formed on the surface layer portion of the particulates, and a rapid pressure reduction is applied to the entire surface of the particulates. Micro cracks are generated, and the gelatinization layer is formed in a dense vitreous quality. As a result, when the rice meal is immersed in the next step, water is evenly and quickly absorbed into the fine grains from the minute cracks in the entire fine grain, and sufficient swelling is achieved without destroying the fine grains due to the minute cracks. Therefore, a sufficient porous structure is formed inside the particulate by the drying treatment immediately after swelling, and water permeation during restoration proceeds more rapidly, enabling restoration in hot water faster than before. In addition, since the surface layer portion of the fine grains is formed of a dense vitreous quality, the grains are not crushed or eluted during cooking or swelling and soaking, and the yield is improved compared to the prior art.

In the pressure heating treatment, it is preferable to pressurize at a pressure of 0.10 to 0.30 MPa, hold for 30 to 120 seconds, and then reduce the pressure to atmospheric pressure within 5 to 30 seconds.

By carrying out the pressurized heat treatment, after maintaining the high-pressure state for 30 to 120 seconds, by reducing the pressure to atmospheric pressure at once within 5 to 30 seconds, the gelatinization layer formed on the surface layer of the fine grain is densely vitrified, and the entire surface of the fine grain is of an appropriate size Even formation of micro cracks can be reproduced effectively.

Further, the water content of the fine grains immediately after the cooking may be 60 to 70%, and the water content of the fine grains after the swelling and immersion may be 75 to 80%. By adjusting the water for rice cooking and adjusting the water content of the rice immediately after cooking to 60 to 70%, swelling of the rice grains proceeds smoothly in the next immersion step, and the water content targeted for swelling and immersion is 75 to 80% in a short time can reach

According to the present invention, it is possible to provide a method for producing instant rice that can be restored faster than before by promoting water absorption and permeation of water during cooking or the like.

The above and other objects and features of the present invention will become clear from the following description of the embodiments with reference to the accompanying drawings. Among them drawing:
1 is a production flowchart in a method for producing instant rice according to an embodiment of the present invention.
2 is an explanatory diagram of pressurization and rapid decompression in the pressurized heat treatment according to the present embodiment.
Fig. 3 is an enlarged cross-sectional photograph of fine grains in the case of reducing the pressure for 10 seconds after increasing the pressure at 0.3 MPa.
Fig. 4 is an enlarged cross-sectional photograph of fine particles when the pressure is reduced for 30 seconds in the same way.
Fig. 5 is an enlarged cross-sectional photograph of fine particles when the pressure is reduced for 60 seconds in the same way.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on the manufacturing flow diagram of FIG.

The raw material rice (raw material polished rice) in the present invention is generally commercially available polished rice, and the water content should just be 16% or less, and there are no restrictions on the variety in particular. The raw material rice may be uncooked rice before washing or soaking, or so-called non-washed rice.

Step S1: Pressurization process

In this pressure cooking step, prior to the subsequent cooking step, pressurized heat treatment with saturated steam is performed in order to form a thin gelatinized layer on the surface layer of the rice grains without gelatinizing the raw material rice to the center. The apparatus for performing this treatment may be a conventionally known steam cooker. For example, a net conveyor for carrying in fine grains into a sealed pressurized heating tank is formed horizontally, and a conveyance start end of the net conveyor A raw material supply pipe on the upper side of the side and a discharge pipe for the processed raw material on the lower side of the conveying end side face each other, and the raw material supply pipe and the raw material discharge pipe keep the inside of the pressurized heating tank airtight. To form a rotary valve or the like. In addition, a supply pipe and a discharge pipe of pressurized heating steam (saturated steam) are connected to the pressurized heating tank.

In the pressure cooking step of step S1, the pressure in the pressure heating tank is gradually increased by supplying saturated steam in a pressure heating state into the pressure heating tank, and the pressure is raised to 0.1 to 0.3 MPa, preferably 0.3 MPa, for about 120 seconds. After maintaining this state for 30 to 120 seconds, preferably 60 seconds, the discharge pipe is opened and rapidly reduced to atmospheric pressure for 5 to 30 seconds, preferably 10 seconds (see Fig. 2).

An alpha layer is formed in the surface layer portion of the fine grains by the pressurization process. Comparing the case of 0.1 MPa and the case of 0.3 MPa, the processing temperature is higher in the case of 0.3 MPa (140 ℃ or more), and the gelatinization layer tends to be formed relatively thick. On the other hand, in the case of 0.1 MPa, the gelatinization layer is relatively thin, so the texture of both is slightly different. Therefore, by changing the pressure, instant rice with different textures can be made separately.

Further, the supply of the saturated steam is not only the supply of the saturated steam, but pressurized and heated by using the saturated steam and compressed air together, thereby improving the pressurization efficiency and preventing the generation of dew condensation water.

In the pressure increase step S1, an gelatinization layer of about 0.1 to 0.5 mm in the surface layer portion of the fine grain is formed, and microcracks are generated substantially equally over the entire surface of the fine grain by the rapid pressure reduction. These microcracks are formed with a length of about 100 μm when the pressure is rapidly reduced from 0.3 MPa to atmospheric pressure for 10 seconds (see Fig. 3), and they are dotted holes when the pressure is reduced for 30 seconds at the same pressure (see Fig. 4) , almost no change was observed in the decompression for 60 seconds (see Fig. 5). On the other hand, in the case of rapid pressure reduction in a short period of less than 5 seconds, problems such as vigorous boiling of the fine particles and non-uniformity of cracks occur.

Further, by the rapid decompression treatment, the gelatinization layer of the surface layer portion of the fine particles is formed of a dense glassy quality.

Step S2: Cooking Process

The cooking step S2 is a step of completely gelatinizing the fine grains, which are subjected to the pressure cooking treatment to form a dense gelatinization layer on the surface layer and generate substantially uniform microcracks over the entire surface. As the rice cooker, it can be suitably selected from well-known rice cookers such as steam rice cooker and pot rice cooker. At this time, the water for cooking is adjusted so that the moisture content of rice immediately after cooking is 60 to 70%, which is higher than the normal 60 to 62%. For example, in the case of cooking in a pot, about twice the weight of the rice grains is added to the cooking pot as water for cooking, and the soaking time in the pot is 15 minutes, the cooking time is 20 minutes, and the steaming time is 50/15. do it in minutes.

In the cooking step S2, the fine grains are not easily crushed by the dense and vitreous gelatinization layer formed on the surface layer, so that the particle feeling of the fine grains at the time of restoration is obtained, but on the other hand, a factor that hinders smooth absorption into the inside of the fine grains As a result, microcracks are generated evenly over the entire surface of the microparticles, and absorption from the microcracks into the interior of the microparticles is uniformly promoted, and alphanization is completely performed to the center of the microparticles.

Step S3: Swelling immersion process

In the swelling immersion step S3, the rice cooked in the cooking step S2 is immersed in hot water at a temperature of 50 to 90°C, preferably 70°C, for 40 to 60 minutes. In this swelling immersion step S3, it swells by making it absorbate so that the water content of a fine particle may become 75 to 80%. At this time, the fine particles do not blow and lose shape due to the dense gelatinization layer of the surface layer portion of the fine particles, while the permeation of moisture through the micro cracks becomes active. In addition, even if the fine particles are swollen and the volume is increased to, for example, about 1.5 times, the presence of the microcracks prevents large cracks in the longitudinal direction of the fine particles, and the surface of the fine particles can be stretched to sufficiently swell.

In the swelling and immersion step S3, along with the swelling of the fine grains, the viscosity of the surface of the rice meal is removed to promote single grain formation. In addition, when the temperature of the immersion water is set to 70 ° C. or higher, there is an effect of suppressing the growth of bacteria. However, when the temperature exceeds 90°C, elution of the surface of the fine particles starts and the yield decreases, which is not preferable.

Step S4: Drying process

In drying step S4, the swollen fine particles placed on a net conveyor or the like are ventilated for 25 to 60 minutes with hot air at 100 to 130°C, and the moisture content of the fine particles is dried to 5 to 10%. At this time, a porous structure is formed in the place where the moisture in the swollen fine particles is removed (porous formation), whereby absorption into the fine particles at the time of restoration proceeds more rapidly.

[Example]

In 2015, Koshihikari polished rice from Hiroshima Prefecture, Japan (90% polished yield, 14% water content) was prepared, pressurized at 0.3 MPa for 120 seconds with saturated steam at 144 ° C. and held for 60 seconds without washing or soaking. The pressure was rapidly reduced to normal pressure in 10 seconds. As a result, an α-modified layer was formed in the surface layer portion of the fine particle, and minute cracks were generated substantially uniformly over the entire surface of the fine particle. The moisture content of the fine particles at this time was 18%. Next, using a normal rice cooker for home use, the rice was cooked for 45 minutes by adjusting the number of times of cooking, and rice rice having a water content of 66% was obtained.

Next, the rice meal was taken out of the rice cooker and immersed in hot water at 60°C, followed by a swelling and immersion treatment for 40 minutes. The moisture content of the microparticles after swelling was 75 to 80%. Then, hot air at 130°C was blown into the fine particles for 30 minutes at a wind speed of 7.5 m/sec to dry the particles to a moisture content of 8%.

Table 1 shows the results of the recovery test for comparing the instant rice obtained in the above example with the instant rice not subjected to rapid pressure reduction in the pressure cooking step. All of the samples were 50 g, each was restored by adding 90 ml of water and hot water to the stand pack container, and then eaten.

As a result, in this example, it was possible to restore in 5 minutes in the case of adding hot water and in 25 minutes in the case of water, respectively, and the taste was excellent with a moderate graininess. Moreover, the yield with respect to the raw material rice was 81.35%, exceeding the 70% range by the conventional manufacturing method.

According to the present invention, it is very useful because it is possible to mass-produce instant rice with excellent recovery properties and high yield compared to the prior art.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the example of embodiment mentioned above, It can implement in other aspects by adding an appropriate change.

Claims (3)

A method for producing instant rice, wherein raw rice is subjected to pressure and heat treatment to form an gelatinization layer on the surface layer of the rice grains, followed by cooking, and drying the cooked rice grains,
The pressurized heating treatment is a pressurized steaming treatment using saturated steam, which includes a step of rapidly reducing the pressure after maintaining a pressurized state for a certain period of time to generate minute cracks on the entire surface of the rice grains. Forming a swelling dipping process for swelling;
The pressurized heat treatment is performed by pressurizing at a pressure of 0.10 to 0.30 MPa, holding for 30 to 120 seconds, and then reducing the pressure to atmospheric pressure within 5 to 30 seconds,
In the swelling and immersion step, the rice cooked rice is immersed in hot water at 50 to 90°C to swell. According to claim 1,
The method for producing instant rice comprising setting the moisture content of the cooked rice immediately after the cooking to 60 to 70% and setting the moisture content of the fine grains after the swelling and immersion to 75 to 80%. delete

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