JP2005168490A - Method for producing new dried water-absorption rice - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing new dried water-absorption rice, making it possible that the rice to which water is added and which is heated and cooked strongly smells pleasantly as if freshly cooked rice does. <P>SOLUTION: This method for producing the new dried water-absorption rice comprises heating raw material rice, such as soaked rice, washed rice, wash-free rice, unpolished rice, and glutinous rice, at a high temperature in a short time, forming a pasty layer which is gelatinized on the surfaces of grains of the rice, heating the raw material rice having the formed pasty layer in water, hot water, boiling water, or an aqueous solution, such as stock, at a temperature (of the raw material rice) of 75°C to 98°C for 30 sec to 20 min, and subjecting the heated rice to air drying and/or reduced-pressure drying treatment, so that the produced dried water-absorption rice has a water content of less than 43% and not less than 10%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a novel dry water-absorbed rice having a starch grain group in which starch grains are rearranged due to thermal fluctuation at the center of water-absorbed rice and having a moisture content of less than 43% to 10%. is there. If the newly dried water-absorbed rice obtained is hydrated and cooked, the scent of freshly cooked rice can be strongly produced.

Conventionally, the production of water-absorbing rice has been performed by stopping the heating halfway without completely cooking the raw rice, and then allowing the rice grains to absorb water.
A typical example of water-absorbing rice is shown in Patent Document 1 as follows.
That is, in the first stage, water-absorbed rice having a water content of 38 to 115 parts by weight with respect to 100 parts by weight of rice is prepared using hot water, steam and / or pressurized steam in the first stage. Refrigeration, freezing, freezing after refrigeration, refrigeration after freezing, and then immersing in water, hot water, dashi juice, soup, sauce, etc. for a certain period of time in the second stage, further absorbing water, and total water absorption Superabsorbent rice with 72 to 130 parts by weight of water per 100 parts by weight. "
Japanese Patent No. 2821562

These water-absorbing rices are not completely gelatinized, and the degree of gelatinization is “50% to 75% in terms of the method for measuring the degree of gelatinization (degree of gelatinization) by the glucoamylase method disclosed in Non-Patent Document 1.” It was about 1%, and it was intended to generate a scent of freshly cooked rice when cooked before meals.
July 15, 1991, 11th edition, published by Asakura Shoten, “Starch Science Handbook”, pages 242-243

  However, when the conventional water-absorbing rice with a degree of gelatinization of 50% to 75% is cooked, for example, when heated in a 500 W microwave oven for 2 to 5 minutes, a certain degree of freshly cooked rice can be produced, It was not as good as the scent of freshly cooked rice when cooked well in a kettle.

  In the present invention, even when water-absorbed rice having a degree of gelatinization of about 85% to 35% is obtained, dry cooked rice that produces a freshly cooked scent comparable to the scent of rice when cooked and cooked well in a kettle is obtained. Was an issue.

In the present invention, raw rice such as soaked rice, washed rice, non-washed rice, brown rice, and glutinous rice is heated at a high temperature for a short time to form a paste-like layer on the surface of the rice grain, resulting in a paste obtained The raw material rice with a layered layer is heated in an aqueous solution such as water, hot water, hot water or dashi juice at 75 ° C. to 98 ° C. (article temperature) for 30 seconds to 20 minutes, and then air-dried and / or vacuum-dried. About the obtained dried water-absorbed rice, when it is heated and cooked, the scent of freshly cooked rice is strongly felt, and the freshly cooked rice is superior to the scent of rice when the water-absorbed rice of Patent Document 1 is cooked by heating. Admitted that there is a scent.
When the dried water-absorbed rice obtained in the present invention was divided into a portion of the water-absorbed rice before drying (water content 65%) and the inside was taken in a scanning electron micrograph, it was found in the center of the rice grain. We found a rearranged starch granule group of starch granules due to no thermal fluctuation. The dry water-absorbed rice obtained in the present invention is obtained by reducing the water content of the water-absorbed rice, and there is no particular change in the internal structure.

The novel dry water-absorbing rice obtained in the present invention has the following rational properties.
1. Does not contain starch grains peculiar to raw rice.
2. It has a glued and glued layer on the surface.
3. Inside the glued layer, there are starch granules swollen including the starch in a molten state, except for the central part.
4). In the center, it has a rearranged starch grain group of starch grains due to thermal fluctuation.
5). The three-layer structure of the gelatinized and paste-like layer, the starch granules swollen by including the starch in a molten state, and the rearranged starch granules of the starch granules due to thermal fluctuation is the scanning electron microscope of FIG. As shown in the photo.
6). When cooked, it produces a strong scent of freshly cooked rice.

Next, water-absorbed rice, fresh rice, and commercially available rice before drying according to the present invention will be described with reference to FIGS. 1 to 9 are all scanning electron micrographs.
FIG. 1 shows the cut surface of the water-absorbed rice (water content 65%) before air drying in the present invention. On the right side of the rice grain is a slightly thick white paste layer, and on the left is a thin white paste layer.
In addition, there is an inverted triangle in the center, and there is a part that looks a little black. This is a group of rearranged starch granules of starch granules due to thermal fluctuations, which has not been confirmed in the past, and is recognized to be hardly gelatinized (α-formation). This can be seen well in FIG.
Also, except for the inverted triangular rearranged starch grain group at the center, the middle of the paste-like layer is filled with the swollen starch grains containing the melted starch.
As shown in the substitute photograph of FIG. 6, the raw rice starch granules appear to be hard with a slight gap, but these are non-gelatinized starch granules.
On the other hand, in the swollen starch granules of FIG. 1, the starch grains of raw rice of FIG. 6 are swollen as they are, and the starch granules remain as they are. The swelling of the starch granules and the starch granules are clearly observed on the right side of FIG. On the other hand, as shown in FIG. 9, the cut surface of the commercially available rice is symmetrical because the inside is completely gelatinized and the starch film is disturbed.

FIG. 2 is a partially enlarged photograph of FIG. In FIG. 2, the lower part of the inverted triangle in FIG. 1 is seen, and here, the rearranged starch grain group of starch grains due to thermal fluctuation can be clearly observed. In addition, the swollen starch granules containing the starch in a molten state can be clearly observed except for the rearranged starch granules having a slightly blackish color.
FIG. 3 is a photograph of the surface of the rice grains of the water-absorbing rice of the present invention. It can be seen that the surface is covered with a layer of glue.
FIG. 4 is a photograph of the surface of fresh rice after bubble washing. You can see that there are cracks in some places.
FIG. 5 is a photograph of the cut surface of raw rice. It can be seen that the whole rice grain is almost uniformly filled with starch grains.
FIG. 6 is a partially enlarged photograph of FIG. Now, it is observed that the starch grains inside the raw rice are filled with gaps little by little.

FIG. 7 is a photograph of the surface of rice grains of commercially available rice at normal temperature (water content 65%). The entire surface is glued and glued, and the left side is partially missing.
FIG. 8 is a photograph of the rice grains in FIG. It can be observed that there is a glued layer around, the inside is gelatinized, the starch grains are broken, and the starch film is disturbed.
FIG. 9 is a partially enlarged photograph of FIG. It can be seen that the entire inside of the rice grain is gelatinized uniformly, and the starch film is disturbed.

The novel dry water-absorbing rice production method of the present invention includes the following three steps.
1. Raw rice such as soaked rice, washed rice, non-washed rice, brown rice, and glutinous rice is heated at a high temperature for a short time to form a paste-like layer on the surface of the rice grain.
2. The obtained raw rice having a glue layer is heated in an aqueous solution such as water, hot water, hot water or dashi juice at 75 ° C. to 98 ° C. (product temperature) for 30 seconds to 20 minutes. By this heating, the degree of gelatinization of the rice grains is 85% or less, preferably 80% to 35%, more preferably 75% to 50%.
The degree of gelatinization of the heated rice grain is 85% or less, preferably 80% to 35%, more preferably 75% to 50%.
3. The raw material rice having a glue layer is heated to a degree of alpha conversion of rice grains of 85% or less, preferably 80% to 35%, more preferably 75% to 50%, and then air-dried and / or vacuum-dried to the following The novel dry water-absorbing rice of the present invention having the following physicochemical properties is produced.
(Physical and chemical properties)
1. Does not contain starch grains peculiar to raw rice.
2. It has a glued and glued layer on the surface.
3. Inside the glued layer, there are starch granules swollen including the starch in a molten state, except for the central part.
4). In the center, it has a rearranged starch grain group of starch grains due to thermal fluctuation.
5). The three-layer structure of the gelatinized and paste-like layer, the starch granules swollen by including the starch in a molten state, and the rearranged starch granules of the starch granules due to thermal fluctuation is the scanning electron microscope of FIG. As shown in the photo.
6). When heat-treated, it produces a strong scent of freshly cooked rice.

The first step of the present invention is to paste only the surface in the state of raw rice to make a paste-like layer, but when it is cooked before eating water-absorbed rice, the rice is bound. It is also useful for preventing dangling. In addition, this glue layer prevents rapid water absorption by the heat treatment in the next aqueous solution, and helps to form rearranged starch grains of starch grains due to thermal fluctuations in the center of rice grains. .
In this first step, raw rice such as soaked rice, washed rice, unwashed rice, brown rice, and glutinous rice is placed in a colander and placed in a container, pressure vessel or conveyor, steam, heated steam, pressurized steam, pressurized Using a heating means such as high-temperature water, the layer can be formed on the surface of the rice grain by heating at 100 ° C. to 200 ° C. for 2 seconds to 600 seconds, preferably with immersed rice for 120 seconds to 240 seconds.

The raw rice from which the glue layer is made is 75 ° C to 98 ° C in an aqueous solution such as water, hot water, hot water or dashi juice in an apparatus or container such as a rice cooker, rice cooker, flat circular or square tray. Heated at (product temperature) for 30 seconds to 20 minutes.
This heating should be a degree of gelatinization of the starch of rice grains up to 85%, preferably 80% to 35%, more preferably 75% to 50%.

In addition, when using a container such as a flat circular or square tray, put raw rice with a paste-like layer in a container such as a tray, put an aqueous solution slightly more than the desired water content, and use a heating device. When heated to achieve a degree of gelatinization of 85% to 35%, more preferably 75% to 50%, take it out of the heating device and leave it air-dried and / or vacuum-dried to a moisture content of less than 43% to 10%. % Water-absorbing rice.
In addition, when using rice cookers, rice cookers, etc., put raw rice with a glue layer into a container made of wire mesh, submerge it in a rice cooker or rice cooker containing an aqueous solution, heat, and a degree of alpha of 85% -When 35%, preferably 80% to 35%, more preferably 75% to 50% pregelatinization is achieved, take out the wire mesh container containing rice grains from the rice cooker or rice cooker and place it on a plastic plate or wire mesh Spread the rice grain on the conveyor and blow it with a fan provided above the plastic plate while occasionally stirring it with a stirring blade to air dry, or blow it with a fan provided above and below the wire mesh conveyor and move it. It is preferable to place a horizontal bar under the net and perform air drying so that when the rice grain exceeds the horizontal bar, the rice grain is shifted and stirred. If this air drying treatment is performed under reduced pressure or under vacuum, it is efficient and can achieve a desired water content in a short time.

In the present invention, in the air drying and / or vacuum drying treatment, the water content is adjusted to less than 43% to 10%, preferably 38% to 15%, more preferably 33% to 20% to produce dry water-absorbed rice. .
The state of dried water-absorbing rice changes depending on the amount of water remaining.
Those with a moisture content of less than 43% to 20% are slightly soft and feel sticky. Also, dry water-absorbed rice with a moisture content of 20% to 10% feels hard, but is suitable for long-term storage. The water-absorbing rice with these moisture contents is preferably refrigerated or stored at room temperature, and is cooked with a proper amount of water (hot water) and aroma that is freshly cooked by heating in a microwave oven (500 W for 3 to 20 minutes). Become.

In the present invention, raw rice such as soaked rice, washed rice, non-washed rice, brown rice, and glutinous rice is heated at a high temperature for a short time to form a paste-like layer on the surface of the rice grain, resulting in a paste obtained The raw material rice having a layer is heated in an aqueous solution such as water, hot water, hot water or dashi juice at 75 ° C. to 98 ° C. (article temperature) for 30 seconds to 20 minutes, and then air-dried and / or vacuum-dried. Thus, the novel dry water-absorbing rice of the present invention can be produced.
The novel dry water-absorbed rice of the present invention has a rearranged starch granule group of starch grains due to thermal fluctuation at the center, and when cooked, it can strongly produce the scent of freshly cooked rice.

  Washed 1.4kg of polished rice, soaked in 40 ° C hot water for 30 minutes, put 1.8kg of the soaked rice in a rice monkey, put it in a pressure cooker, rice pressure at 120 ° C and 2 atm. After reaching 20 ° C., it was heated for about 20 seconds and taken out from the pressure cooker to obtain raw rice having a paste layer on the surface of the rice grain.

2.1 kg of the obtained raw rice having a paste layer is placed in a flat circular tray having a height of 8 cm and a diameter of 45 cm, and 1.3 kg of hot water at 90 ° C. is placed in the heating apparatus.
In the heating device, the product temperature reached 85 ° C. and heated at 85 ° C. for 10 minutes. After the heating was completed, the product was taken out from the heating device and submerged in a water tank (water temperature 5 ° C.) containing ice to 3 cm from the bottom and cooled. While blowing from the left and right with a fan, air-dry.
During air drying, stir occasionally with a rake-like stirrer to promote air drying.
When the water content of the water-absorbed rice reached 39%, the air drying was stopped and 1.95 kg of newly dried water-absorbed rice was obtained.

The dried water-absorbed rice obtained was slightly soft when pressed, but the surface was in a fairly dry state and was suitable for storage at room temperature with the addition of an oxygen scavenger (ageless).
When 112 g of dried water-absorbed rice stored at room temperature for 2 weeks was put into a container, 150 g of hot water was added thereto and heated in a 500 W microwave oven for 7 minutes, a delicious rice scented with strong freshly cooked rice was obtained.

Scanning electron micrograph of the cross section of water-absorbed rice (water content 65%) 1 part enlarged photograph of the photograph of FIG. Scanning electron micrograph of the surface of the water-absorbing rice of the present invention Scanning electron micrograph of the surface of raw rice (milled rice) Scanning electron micrograph of the cross section of raw rice (milled rice) Part of the photo in Fig. 5 enlarged Scanning electron micrograph of the surface of commercially available rice (water content 65%) Scanning electron micrograph of the cross-section of a commercial room temperature rice Part of the photo in Fig. 8 enlarged

Claims (8)

Raw materials such as soaked rice, washed rice, non-washed rice, brown rice, and glutinous rice are heated at high temperature for a short time to form a paste-like layer on the surface of the rice grain, and the resulting raw material with paste-like layer Rice is heated in an aqueous solution such as water, hot water, hot water or dashi juice at 75 ° C. to 98 ° C. (product temperature) for 30 seconds to 20 minutes, and then air-dried and / or vacuum-dried, and the following physicochemical A method for producing a novel dry water-absorbing rice having properties and obtaining water-absorbing rice having a water content of less than 43% to 10%.
(Physical and chemical properties)
1. Does not contain starch grains peculiar to raw rice.
2. It has a glued and glued layer on the surface.
3. Inside the glued layer, there are starch granules swollen including the starch in a molten state, except for the central part.
4). In the center, it has a rearranged starch grain group of starch grains due to thermal fluctuation.
5). The three-layer structure of the gelatinized and paste-like layer, the starch granules swollen by including the starch in a molten state, and the rearranged starch granules of the starch granules due to thermal fluctuation is the scanning electron microscope of FIG. As shown in the photo.
6). When heat-treated, it produces a strong scent of freshly cooked rice.   Raw rice such as soaked rice, washed rice, non-washed rice, brown rice, and glutinous rice is heated at 100 ° C. to 200 ° C. for 2 seconds to 600 seconds using heating means such as steam, heated steam, pressurized steam, and pressurized hot water. The method according to claim 1, wherein the layer is heated to form a paste-like layer on the surface of the rice grain.   A rice cooker, a rice cooker, a plate-shaped circle is heated for 30 seconds to 20 minutes at 75 ° C to 98 ° C (article temperature) in an aqueous solution of raw rice water, hot water, hot water or dashi juice with a glue layer. The method according to claim 1, wherein the method is performed with a rice cooker such as a mold or a square tray.   In rice cookers such as rice cookers, rice cookers, flat circular or square trays, the heating of raw rice having a paste-like layer is not sufficient rice cooking, up to a degree of gelatinization of 85%, preferably 80% to 35 %, More preferably 75% to 50% of the heating.   After drying, the raw rice with the glue layer is taken out from the aqueous solution, placed on a flat plate or on a conveyor, and the moisture content of the water-absorbed rice is less than 43% with warm air, room temperature air or cold air The method according to any one of claims 1 to 4, wherein the method is air-dried to 10%, preferably 38% to 15%, more preferably 33% to 20%.   In the case where a flat circular or square tray is used, air drying and / or reduced pressure drying treatment is performed by heating the raw rice having a paste-like layer and taking it out with the aqueous solution as the tray, and then air drying and / or reduced pressure. Drying treatment is performed, and the water content of the water-absorbing rice is adjusted to less than 43% to 10%, preferably 38% to 15%, more preferably 33% to 20%. The method described.   During the air drying and / or vacuum drying treatment, the water content of the water-absorbed rice is agitated from above the water-absorbed rice with a stirrer etc. The method according to claim 6, wherein the method is adjusted to ˜20%.   In the air drying and / or vacuum drying treatment, air drying and / or vacuum drying treatment is performed while cooling the bottom of a flat circular or square tray containing heated water-absorbing rice with chilled water at 3 ° C to 7 ° C. 8. A method according to any of claims 1 to 7, characterized in that