JPH1175732A - Boiled rice food capable of being distributed and sold at low but non-freezing temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a boiled rice food capable of preventing texture change at a low temperature zone in the boiled rice food using a common nonglutinous rice, and capable of being distributed and sold at a low but non-freezing temperature, especially the boiled rice food capable of being distributed at the low temperature and capable of being eater without heating. SOLUTION: This boiled rice food is the one obtained by using a boiled rice of a polished rice of a nonglutinous rice and capable of being distributed and sold at a non-frozen low temperature, especially the low temperature of <=15 deg.C. A preferable style of the boiled rice food capable of being distributed and sold at the low temperature of <=15 deg.C is the style of the boiled rice food distributed and sold in chilled state. The boiled rice food can be digested without heating. Increase of water content in the boiled rice food is most effective, and the boiled rice has >=58%, preferably >=60% or >=62%, most preferably >=65% water content. The boiled rice food with seasoning, especially sushi, is preferable as the kind of the boiled rice food because the change of texture is small while preserving the boiled rice food at the low temperature. Aging resistance can be improved by the use of an additive, and the boiled rice food includes the food additive especially salts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cooked rice foods which can be distributed and sold at a low temperature without being frozen. More specifically, the present invention relates to cooked rice food using cooked rice which is hard to be hardened even when stored at low temperature without being frozen and maintains stickiness. In the present invention, “low temperature” means 15 ° C. or less, or “chilled” means 10 ° C.
Below, it means the temperature zone which does not freeze.

[0002]

2. Description of the Related Art Cooked rice cooked with rice hardens over time. This phenomenon is called aging of cooked rice, and the degree of the change is greater at low temperatures. Aging is the change over time of starch, starch that has been gelatinized by water and heat,
It is said to occur due to recrystallization. Methods for suppressing the aging of cooked rice include enzymes (α-amylase, β-amylase, glucoamylase, protease, etc.), starches (α-modified starch, modified starch, etc.), polysaccharides (julan gum, hyaluronic acid, etc.), saccharides ( Anhydrosugar,
Dextrin, glucose, fructose, cyclodextrin), sugar alcohols (trehalose, maltitol,
Sorbitol, lactitol and the like) and emulsifiers (sucrose fatty acid ester, polyglycerin fatty acid ester, organic acid monoglyceride) and the like.
Although each of these has some effect, aging of cooked rice cannot be suppressed only by these techniques. For example, in any place or combination using any of the above techniques, cooked rice stored at normal 5 ° C. for 24 hours is hard and difficult to eat as it is.

[0003] For the above reasons, rice once stored at a low temperature requires heating in a microwave oven or the like. Therefore, generally, in a bento prepared food shop, rice is distributed and sold in a frozen state at 15 ° C. or higher, where rice is less aging, assuming that it is eaten as it is. That is, aging of cooked rice is suppressed if it is distributed and sold at a temperature of 15 ° C. or higher. However, in this temperature range, propagation of bacteria becomes a problem, and it is necessary to use a bacteriostatic agent or the like. Therefore, bacteriostatic agents must be used for side dishes that can be stored at lower temperatures (there is little change at low temperatures).
On the other hand, frozen prepared foods have little aging of cooked rice, but the texture change due to frozen denaturation of side dishes such as vegetables is remarkable, and microwave ovens are always required when trying to eat this prepared food immediately. . On the other hand, in particular, frozen sushi, in which the texture of cooked rice is regarded as important, and which is difficult to heat and thaw, often contains a large amount of sugars and food surfactants in order to suppress the aging of cooked rice. You may even feel a bad smell.

[0004] It is known that glutinous rice, which has a different genetic property from glutinous rice, has high aging resistance. However,
Glutinous rice has a peculiar smell, and its texture is too sticky, so it is not suitable for the above prepared foods.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to suppress a change in texture of cooked rice food using general glutinous rice in a low temperature range. That is, an object of the present invention is to provide cooked rice food that can be distributed at a low temperature, particularly low-temperature cooked rice that can be eaten without heating.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies on suppressing the change in texture in the low temperature range, particularly on the use of general glutinous rice, and have increased the water content of cooked rice foods. Was the most effective, and it was clarified that as a type of cooked rice food at that time, a change in texture during storage at low temperature was small when a seasoning was added. Furthermore, it has been clarified that the use of additives can improve aging resistance, and among the additives, the effect of adding salts is the highest, and among them, the effect of adding Ca salt is high. The present invention has been completed based on these findings.

[0007] The present invention relates to a cooked rice food product which can be distributed and sold at low temperature without freezing using rice cooked from polished rice, particularly at 15 ° C.
The gist is the following cooked rice foods that can be distributed and sold at low temperatures. A preferred embodiment of the cooked rice food product that can be distributed and sold at a low temperature of 15 ° C. or less is a chilled distribution rice food product. Cooked rice food can be eaten without heating. It is most effective to increase the water content of cooked rice food, and the cooked rice has a water content of 58% or more, preferably 60% or more or 62%.
The above is most preferably cooked rice of 65% or more. As the type of cooked rice food at that time, the one to which a seasoning is added has a small change in texture during storage at a low temperature, and the cooked rice food is a food to which a seasoning is added, particularly "sushi". Further, by using an additive, aging resistance can be improved, and the cooked rice food contains a food additive, particularly a salt.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of a test for the amount of water, when rice is cooked with a water content of 1.35 to 1.80 times that of raw rice, an appropriate addition is made depending on the rice variety and the type of cooked rice product. Although the amount of water was slightly different, the quality could be maintained for up to 48 hours under storage at 5 ° C. By controlling the water content of the rice in the range of 58% to 68% without adding any additives, the texture can be maintained even when stored at a low temperature (the water content of the rice is usually 135 ° C.). This is the moisture content measured by the drying method at the time of pressing, and means the moisture content of white rice, that is, rice food to which a large amount of seasonings is added, such as sushi, is about 2 to 4% more than the moisture content shown here. Lower value).

[0009] That is, when white rice cooked by an ordinary commercially available electric rice cooker is obtained, with a general amount of water of 1.20-fold water-cooked rice (water content: 58%), it hardens immediately with the lapse of time during low-temperature storage. Becomes unsuitable for edible use. But,
Increasing the moisture content of rice from 58% to 60% and 62% extends the quality maintenance period. For example, onigiri adjusted with Koshihikari can maintain the quality for about 24 hours at 5 ° C. storage at a water content of about 60%, and can maintain the quality for 48 hours by increasing it to 62% or more.

Further, it has been confirmed that, in a low temperature range, increasing the amount of water can suppress fluctuations in quality changes during storage, such as the hardness and stickiness of cooked rice. In other words, when the amount of water is small, the amount of increase in the hardness of the rice is considerably large, and the speed at which the rice is hardened is large, and eating is not possible in a short time, but the hardness is increased by increasing the amount of water. The amount and the speed of its change can be slowed and the shelf life can be extended. That is, the amount of water can be determined according to the target quality maintenance period. If the time is short, the amount of water is usually slightly larger than the amount of water for cooking, and if the time is relatively long, the amount of water is more than that. However, depending on the cooked rice product, the amount of water must be adjusted.

It is considered that the above-mentioned effect of suppressing the hardening of the texture by the addition of water reduces the density of the starch molecules due to the increase in the amount of water, and the interaction between the molecules hardly occurs. Therefore, the rearrangement of the molecules hardly occurs. Can be

[0012] Difficulty in maintaining quality during low-temperature storage differs depending on the type of cooked rice food. Quality is easily maintained in a form to which a seasoning is added, and is represented by, for example, sushi and onigiri. Compared with these forms, it is difficult to maintain the quality of white rice.

In the present invention, aging resistance can be further improved by adding a food additive in addition to controlling the amount of water or forming a food with a seasoning added thereto. . Examples of the food additive include enzymes, starches, polysaccharides, sugars, sugar alcohols, emulsifiers, and salts. Specifically, the enzyme
α-amylase, β-amylase, glucoamylase,
It is effective to add the protease in an amount of 0.01 to 100 U / g of rice, and these are also effective before or after cooking.

Suitable starches include waxy corn starch, shiratamako, tapioca starch or modified starch having a high content of amylopectin, and degraded starches thereof, and 0.5 to 20% (W / W) based on raw rice.
Addition is suitable. Other sugars include duran gum (versus rice; (W / W) 0.1-5.0%), hyaluronic acid (0.05-0.8%), and anhydroic acid (0.3-0.3%).
3.0%), dextrin (0.5-20%), cyclodextrin (0.5-20%), and oligosaccharide (0.5-20%). Trehalose, lactitol, maltitol, and sorbitol are effective as sugar alcohols. As the emulsifier, it is effective to add a sucrose fatty acid ester, a polyglycerin fatty acid ester, an organic acid monoglyceride, lysolecithin, and a diglycerin fatty acid ester. Preferably, an emulsifier having an HLB of 12 or more is added to raw rice in an amount of 0.05 to 1.0% (W / The addition of W) is effective.

Among these additives, the effect of adding salts is particularly large, and one of the reasons why the cooked rice food to which the above-mentioned seasoning is added has high aging resistance is considered to be the effect of adding these salts. In other words, sushi and onigiri are usually added with Na salt and the like, and it is considered that due to the effect of these salts, aging resistance is higher than that of white rice. Sufficient effects can be obtained by adding these salts at a concentration that does not affect the taste.
This is clear from the example of sushi and onigiri that the effect is sufficiently obtained when used at a general concentration for the purpose of seasoning.

Among the types of salts, Ca salt is particularly effective, and its concentration is 0.05% with respect to the total weight.
As described above, preferably, the effect can be obtained by any addition after processing. For example, when added to a rice immersion liquid after washing rice, or when added as a solid to cooked rice, a texture retention effect can be obtained in any case.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments. The present invention is not limited by these examples.

Changes in texture during low-temperature storage were measured by the following method. Rice was cooked with a predetermined amount of water using a commercially available electric rice cooker. After steaming these, they are molded into a predetermined form,
After being transferred to a tray and packaged with filter paper and film, it was stored in a freezer at 5 ° C. 1.2 after 24 or 48 hours
Based on Koshihikari cooked with 0 times the amount of water, sensory evaluation was performed by a specialized rice panel.

Example 1 Example of amount of water To 300 g of raw Koshihikari rice, the amount of water was 1.35,
The rice was cooked by changing it to 1.50, 1.65, and 1.80 times. After cooking rice, adjust the white rice, rice balls, and sushi.
The sensory evaluation was carried out when stored at 48 ° C. for 48 hours. The evaluation criteria were ◎ for soft and strong stickiness, 〇 for soft and sticky, △ for slightly hard and less sticky, and × for very hard and less sticky.

[0020]

[Table 1]

As the amount of water added (moisture content of rice) increased, the shelf life at 5 ° C. could be extended. That is, the white rice was highly evaluated by the panel even after 24 hours with a water content of 65% or more. The quality of onigiri and sushi could be maintained by increasing the amount of water even after 48 hours. In addition, rice balls were less aging than white rice, and sushi rice more than rice balls, and the quality retention period was longer without increasing the amount of water significantly.

Example 2 Example of the amount of water The amount of water was 1.35 with respect to 300 g of raw Koshihikari rice.
The rice was cooked by changing it to 1.50, 1.65, and 1.80 times. Immediately after the cooked rice was cooked, the sensory evaluation when stored in a refrigerator at 5 ° C. for 24 hours was as shown in the table. Here, the change in stickiness will be described. When the amount of water was small, the amount of decrease in viscosity (the amount of change in the table) was considerably large, but by increasing the amount of water, the amount of decrease in viscosity after storage could be suppressed to some extent. That is, the aging rate of cooked rice could be reduced by increasing the amount of water.

[0023]

[Table 2]

[0024]

According to the present invention, it is possible to provide a cooked rice product using general glutinous rice with less deterioration of the texture during storage at a low temperature by suppressing the change of the texture in a low temperature range.

Claims (13)

[Claims] 1. A cooked rice food product using rice cooked rice, which is made of polished rice, which can be distributed and sold at low temperature without being frozen. 2. The cooked rice food product which can be distributed and sold at a low temperature of 15 ° C. or lower and which can be distributed and sold at an unfrozen low temperature. 3. The cooked rice food product according to claim 2, which is a chilled rice cooked food product that can be distributed and sold at low temperature. 4. The cooked rice food product according to claim 2 or 3, wherein the cooked rice food product can be eaten without heating. 5. The cooked rice food product according to claim 1, which is cooked rice having a water content of 58% or more. 6. The cooked rice food product of claim 5, which is cooked rice having a water content of 60% or more. 7. The cooked rice food product as claimed in claim 6, which is cooked rice having a water content of 62% or more. 8. The cooked rice food product according to claim 7, which is cooked rice having a water content of 65% or more. 9. The cooked rice food product according to any one of claims 1 to 8, wherein the cooked rice food product has a seasoning added thereto. 10. The cooked rice food product according to claim 9, wherein the cooked rice food product is sushi. 11. The cooked rice food product according to claim 1, which is cooked rice containing an additive. 12. The uncooked cooked rice food product according to claim 11, which contains salts as a food additive. 13. The cooked rice food product according to claim 12, wherein the salt is a Ca salt.