JP3515827B2 - How to make aseptic cooked rice - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing aseptic cooked rice.

[0002]

2. Description of the Related Art Alpha-cooked rice is known as instant cooked rice, but it is necessary to dry the alpha-cooked rice with hot air until the moisture content becomes 8% or less in order to prevent decay and mold. Hot air drying takes time, and quality deterioration becomes a problem.

On the other hand, the retort cooked rice can be stored for a long period in a completely cooked state and can be used for cooking only by heating, but the degree of freedom of the cooking method is low because the moisture content cannot be adjusted. Moreover, there is a peculiar problem that a so-called retort odor due to the vapor mist tends to remain.

Although a method of cooking rice by pressure steaming has been conventionally known, since the rice cooking temperature is at most 110 ° C., there is almost no sterilizing effect and it cannot be used for the production of cooked rice for storage.

The object of the present invention is to cook rice in a short time, to minimize the deterioration of quality, to have no retort odor, to allow the consumer to control the moisture content, and to have a high F value, so-called aseptic cooked rice. Is to manufacture.

[0006]

Method for producing a sterile cooked rice of the present invention for solving the problems To achieve the above object, according to the steps of the washed raw rice was drained accommodated in a pressure vessel, once the vacuum the pressure vessel After that, a step of filling the pressure vessel with high temperature steam and steaming the drained raw rice under pressure / heating at about 130 ° C. to about 140 ° C., an atmospheric pressure level or a negative pressure level in the pressure vessel cooling the steamed rice was reduced to the steps of dispensing housing steaming rice inside opening the pressure vessel in a sealed container, and sterilizing water in the subdivision housing
The process comprises filling the inside of the sealed container . Drained raw rice can be subdivided into, for example, a plurality of cylindrical carrier containers having small holes on the bottom surface, and then the plurality of carrier containers can be housed in a pressure container. The cooking temperature is about 130 ° C to about 140 ° C to obtain a sterilizing effect . Before or after the step of aliquoting housed in tightly sealed container may be inserted a step of loosening the cooking rice. Further, the step of subdividing and storing in a sealed container may be performed in a clean room. Further, the step of returning the pressure vessel to atmospheric pressure and storing the steamed rice in small portions in a sealed vessel may be performed in an atmosphere of an inert gas.

[0007]

[Function] Since the pressure vessel is once evacuated and the high-temperature and high-pressure steam is introduced, the steam circulates to every corner of the raw rice in a short time, and effective and uniform steaming / sterilization is performed. This bactericidal effect is particularly good when the cooking temperature is about 130 ° C or higher. The higher the temperature, the shorter the cooking time. However, if the temperature is too high, the rice components will be destroyed, so it is preferable to set the upper limit to about 140 ° C. Oxidation of rice is prevented by once making the inside of the pressure vessel negative pressure, and since the heat treatment is for a short time, the heat history of rice is small and deterioration of quality can be minimized.

By depressurizing the pressure vessel to the atmospheric pressure level or the negative pressure level after steaming, the steamed rice is quickly cooled and excess water is also removed at this time. Since there is no deterioration and the steam remaining in the small gaps in the pressure vessel and steamed rice is removed smoothly, the so-called retort odor that has been a problem with heat sterilization in sealed vessels such as retort pouches. Does not remain in the product.

Further, a watering step can be added if necessary, and in this case, the water content can be additionally adjusted at the consumption stage by appropriately suppressing the water content to provide the degree of freedom of cooking.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

First, raw rice 1 is washed and immersed in water 3 in a container 2 as shown in FIG. The immersion condition is, for example, water temperature of 10 ° C. for 50 minutes. Immersion in water is not absolutely necessary, but immersion in water is desirable because it makes the cooked rice fluffy.

After immersing the unpolished rice 1 for a predetermined time, it is drained from the container 2 and drained, and the container 2 is housed in a pressure container 4 as shown in FIG. 1 (B). At the bottom of the container 2, it is preferable to form a drain hole 6 for drainage like the small container 2a in FIG. Alternatively, a dedicated large-sized steam cooker may be used as a pressure container without using the container 2 (2a), and the raw rice 1 may be put directly into this steam cooker to perform the same treatment.

A vacuum pipe and a high temperature steam pipe are connected to the pressure container 4, and the vacuum valve is first opened to make the inside of the pressure container 4 a vacuum of, for example, about 30 mmHgabs. It should be noted that, as shown in FIG. 3, a plurality of containers 2a may be housed in a cylindrical laterally elongated pressure container 4a.

Next, as shown in FIG. 1 (C), the vacuum valve is closed and the steam valve is opened to introduce high temperature and high pressure steam into the pressure vessel 4, and the absorbed raw water is steamed and sterilized by heating and pressurizing. , By this, the starch quality of raw rice is gelatinized. At this time, the temperature of rice is at least 130 ° C. or higher, and the cooking time is, for example, 130
C. is about 2 minutes, and 135.degree. C. is about 1 minute. If the temperature is too high, the rice components will be destroyed, so the upper limit is about 140.
It is desirable to set the temperature to ° C. In this steaming / sterilizing treatment, the pressure vessel 4 is once evacuated and high-temperature high-pressure steam is introduced. Therefore, steam is spread to every corner of the raw rice, and effective and uniform steaming / sterilizing is possible even in a short time. In addition, the vacuum prevents the rice from being oxidized, and the heat treatment for a shorter time reduces the heat history of the rice, which can minimize the deterioration of quality.

Next, as shown in FIG. 1 (D), the steam valve is closed and the vacuum valve is opened so that the pressure vessel 4 is reopened to 30 mmHga.
A vacuum of about bs is applied and the steamed rice 1a is cooled in vacuum. Vacuum cooling is capable of rapid cooling, and there is no need for a refrigerant, so there is no risk of contaminating the sterilized steamed rice 1a with a refrigerant such as air or water, and it is more cost effective than cooling with a sterilized refrigerant. . Further, since the steam remaining in the small gaps in the pressure vessel 4 and the steamed rice 1a is strongly removed by vacuum cooling, so-called retort odor does not remain in the product. Even if the pressure is reduced to the atmospheric pressure level instead of the vacuum cooling, the required cooling action and the retort odor removing action can be almost ensured. That is, since the initial pressure is quite high, a considerable reduced pressure cooling effect can be obtained even if the pressure is reduced to atmospheric pressure. Therefore, sufficient cooling is possible by reducing the pressure to any pressure within the range of 760 mmHg to 30 mmHg, for example.

Next, as shown in FIG. 1 (E), the pressure vessel 4 is returned to atmospheric pressure in a clean room and then opened to open the vessel 2 inside.
Is taken out to a clean room, and the steamed rice 1a therein is subdivided into a plurality of small containers 5 such as pouch bags which can be sealed, and then sealed. It is desirable that the clean room has a cleanliness of at least class 100. The sealed steamed rice 1a is shipped as a product, and the consumer adds the desired amount of water to the steamed rice 1a taken out from the small container 5 and heats it in a microwave oven or the like, or eats the steamed rice 1a in the small container 5. It can be transferred to tableware or the like and poured with an appropriate amount of boiling water. After a while, the boiling water is discarded, the tableware is covered with a lid or the like to steam the steamed rice 1a, and then it can be eaten.

It should be noted that , in a form of anticipating the watering work of the consumer, after the cooling step, the steamed rice 1a is made to absorb sterilizing water.
It The spray header 7 of FIG. 3 is disposed in the pressure vessel 4a for water addition during the steaming process, and the sterilizing water is sprayed from the spray nozzle 8 located above each vessel 2a toward the steamed rice 1a, Excess water is drained from the drain hole 6 at the bottom of the container 2a. Further, by adding water immediately after the steaming step, the steamed rice 1a can be pre-cooled with water, so that the production time can be shortened. In this case, if the steamed rice 1a is steamed by allowing it to stand in the pressure vessel 4 for a predetermined time after water addition, a more fluffy finish is obtained. The standard weight ratio of rice and water is 1: 0.9, so if this weight ratio is satisfied in advance by the above water addition process, the consumer can either heat the small container 5 with boiling water, or use the contents of the tableware. You can cook rice by taking it out to a microwave oven or the like and heating it in a microwave oven, etc., and you can eat without adding water. In addition, a predetermined amount of water that has been sterilized in advance to satisfy the weight ratio may be filled in the small container 5 at the stage where the steamed rice 1a is subdivided and sealed in the small container 5. It should be noted that even if the weight ratio of rice: water is in the range of 1: 0.5 to 1.0, there is no particular problem with food, so the amount of water added may be appropriately increased or decreased according to the taste of the consumer.

In order to prevent oxidation, it is desirable to eliminate air as much as possible or to inject an inert gas such as nitrogen or carbon dioxide into the small container 5. If the atmosphere in the clean room is filled with an inert gas and air is prevented from coming into contact with the steamed rice 1a when the pressure vessel 4 is returned to the atmospheric pressure, the antioxidation measure is more complete.

The above treatment can be carried out by various kinds of sterilizers, and a particularly suitable one is the sterilizer of Japanese Patent Application No. 6-208553. This device accommodates a plurality of cylindrical containers with a bottom in a sealed cylindrical processing tank that can swing like a seesaw, and tilts the processing tanks to the left and right so that the internal containers are self-weighted. Rolling in the longitudinal direction of the processing tank,
The food stored in the container is sterilized by heating and pressurizing with steam while stirring by rolling.

[0020]

As described above, according to the present invention, the inside of the pressure vessel is once evacuated, and the raw rice is cooked by heating and pressurizing by introducing high temperature steam to gelatinize the starch quality. Steam is turned around, and effective and uniform steamed rice can be cooked even in a short time.
In addition, the vacuum prevents the rice from being oxidized, and the heat treatment for a shorter time reduces the heat history of the rice, which can minimize the deterioration of quality.

Since the steaming temperature is set to about 130 ° C. or higher, it is possible to simultaneously sterilize steamed rice, which cannot be achieved by the conventional pressure steaming with an upper limit of about 110 ° C., and so-called aseptic cooked rice having a high F value. Can be manufactured.

Further, when the steamed rice is decompressed to a vacuum or atmospheric pressure and cooled, the steam remaining in the small gaps in the steamed rice is quickly removed, so that a so-called retort odor does not remain in the product.

Since steamed rice is cooked with the minimum amount of water necessary for gelatinization, the degree of freedom of cooking can be increased by adding a desired amount of water on the consumer side.

[Brief description of drawings]

FIG. 1 is a schematic view of steps showing the method of the present invention.

FIG. 2 is a cross-sectional view of a small container.

FIG. 3 is a sectional view of a modified example of the pressure vessel.

[Explanation of symbols]

1 raw rice 2 containers 3 water 4 Pressure vessel 5 sealed small containers 6 drainage holes 7 Spray header 8 spray nozzles

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-201954 (JP, A) JP-A-2-65751 (JP, A) JP-A-57-110154 (JP, A) JP-A-6- 46770 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) A23L 1/10

Claims (4)

(57) [Claims] 1. A process for accommodating the washed raw rice drained by a pressure vessel, after once vacuum the pressure vessel, filled with high-temperature steam into the pressure vessel to the raw rice draining state 130 ℃ ~
The step of cooking in pressure and heat at 140 ° C., aliquoted cooling the steamed rice in vacuo the pressure vessel to atmospheric pressure level or negative level, the steaming rice inside opening the pressure vessel to the sealed container Fill the inside of the sealed container with sterilized water during the storing step and during the subdivided storage
A method for producing aseptic cooked rice comprising the steps of : 2. The method for producing aseptic cooked rice according to claim 1, wherein the step of subdividing and storing in the sealed container is performed in a clean room. 3. The method for producing aseptic cooked rice according to claim 1, wherein the step of returning the pressure vessel to atmospheric pressure and storing the steamed rice in a sealed container in small amounts is performed in an inert gas atmosphere. 4. The method according to claim 1, wherein the drained raw rice is subdivided into a plurality of cylindrical carrier containers having small holes on the bottom surface, and then the plurality of carrier containers are housed in the pressure container. Method for producing aseptic cooked rice.