JPH0494654A - Production of frozen boiled rice - Google Patents

Abstract

PURPOSE:To obtain the title boiled rice with transparency and viscosity, excellent in chewability and taste, suitable for the boiled rice for SUSHI by adding a salt to stock rice followed by boiling. CONSTITUTION:The objective boiled rice can be obtained by boiling stock rice incorporated with a salt (pref. common salt, sodium metaphosphate).

Description

[Detailed description of the invention] (1) Industrial application fields The present invention relates to a method for producing frozen cooked rice.

Specifically, this is a method for producing frozen cooked rice that allows rice for sushi to be obtained by natural thawing or hot water thawing.

(2) Conventional technology The taste of cooked rice changes over time, it is prone to spoilage, and starch aging (gelatinized starch crystallizes, resulting in gelatinized starch being converted to beta instead of gelatinized). It has characteristics such as not being able to be stored due to It can be pointed out that these characteristics of rice are one of the reasons why rice, which once occupied the overwhelming position of staple food, has been decreasing year by year due to changes in dietary habits.

In recent years, with the development of freezing technology, frozen transportation technology, and thawing technology, many frozen foods have appeared. Frozen cooked rice is an example of this, and various inventions have been made for its simplicity and productivity. for example,
The method for processing cooked rice in Special Publication No. 58-36355 is [
When rice is processed by an appropriate means to make cooked rice and then frozen, glycerin fatty acid ester is added in one of the steps before freezing, and the rice is filled into a heat-resistant tray and then frozen,
Alternatively, after freezing, the frozen cooked rice in containers is filled into the tray, and then the frozen cooked rice in containers is heat-treated in an oven or microwave as it is during thawing cooking.'' ( scope of claims)
It is. The method for processing frozen cooked rice disclosed in Japanese Patent Publication No. 58-187153 is [a series of manufacturing steps for frozen cooked rice made by washing, cooking, and processing the raw material rice; in the cooking process, starch is mixed and added to an edible dispersion medium. "A method for processing frozen cooked rice" (claims).

The method for producing cooked rice food in Special Publication No. 172262/1986 is as follows:
In a method for producing cooked rice food in which raw rice is cooked and then molded and packaged or packed in containers, an organic acid or its derivative is added before cooking to raise the pH value of the cooked rice to 3.5 to 4.
．． 7, and a method for producing a cooked rice food, which comprises forming and packaging the cooked rice and then freezing it.
(Claims). Special Public License Showa 61-158755
The method for producing cooked rice referred to in this issue is ``a method for producing cooked rice particularly suitable for retort or freezing, which is characterized by carrying out an emulsification process when producing cooked rice by steaming raw rice'' (claims).

However, the frozen cooked rice according to these inventions needs to be thawed using an oven, a microwave oven, etc., and the temperature of the cooked rice must be heated to around or above the gelatinization temperature of starch (70° C.). This is not a problem for general household use, but in places where large quantities are consumed for commercial purposes such as restaurants and mass retailers, ovens, microwave ovens, etc. must be enlarged to match the consumption, which is practically impossible. There are some things. In addition, if it is used for sushi rice, the flavor may change slightly if the vinegar is removed by heating. Additionally, a heat-resistant container is required due to heating. Furthermore, some methods are expensive to manufacture, such as freezing with liquid nitrogen.

(3) Problems to be Solved by the Invention As mentioned above, thawing frozen cooked rice using the conventional technology requires heating the starch to a temperature higher than the gelatinization temperature using an oven, microwave, etc. Even if the equipment was available, there were limitations due to cost and the amount of thawing. Furthermore, a heat-resistant container is also required due to heating. Furthermore, some methods are expensive to manufacture, such as freezing with liquid nitrogen. In addition, if it is used for sushi rice, the flavor may change slightly if the vinegar is removed due to heating.

Therefore, the present invention aims to obtain frozen cooked rice suitable for sushi rice that has the same flavor and texture as regular sushi rice by thawing naturally or in hot water. This eliminates the need for thawing in ovens, microwaves, etc. (4 tc), making it possible to consume large amounts not only for general households but also in restaurants, mass retailers, etc., and also eliminates the need for heat-resistant containers. By lowering the temperature, it is intended to prevent subtle changes in flavor due to vinegar volatilization, etc.

``In addition, the freezing method is to freeze at -25°C to -30°C, making it possible to manufacture it in a regular freezer or deep freezer.

(4) Means for solving the problem Therefore, the present invention involves adding inorganic salt, organic salt, or inorganic salt and organic salt to washed raw rice, cooking the rice, and adding vinegar, sugar, salt, and seasoning to the resulting cooked rice. Mixed vinegar consisting of is added to make it for sushi rice, and after cooling, it is made into a sushi ball of about 23 g by a molding machine, packed in a container, packaged, and frozen by putting it in a -25°C freezer. This led to the solution of the above problem. The details of the method of the present invention will be described below, in which rice is cooked by adding inorganic salts and organic salts. Here, the inorganic salt is common salt, sodium bicarbonate, etc., and the organic salt is sodium #acid, sodium metaphosphate, etc. These salts may be used alone, but from the viewpoint of discoloration of starch, taste of cooked rice, suitability for molding machines, anti-aging effect, etc., the salt and sodium metaphosphate should be added to the raw rice rice at 0.3% by weight based on the rice. Add and cook. Next, add a combination of vinegar, sugar, salt, and seasonings to make sushi rice, and after cooling, put it in a molding machine for 23 minutes.
Make shari balls for nigiri sushi of about 1.5 oz. This is packed in a container, packaged, and placed in a freezer or deep freezer at -25°C to -30°C to freeze.

After 10 days, Sharidama stored at -18℃ or lower after freezing, 1
When the rice was naturally thawed at a room temperature of 15° C. after a month, it was found to be transparent, viscous, chewy, and taste good enough to be used as sushi rice.

In addition, the rice thawed in 50°C warm water had the same texture, taste, and flavor as regular sushi rice, even though it was frozen cooked rice.

As a result, nigiri sushi can be easily obtained by adding wasabi to the defrosted rice balls and placing sushi toppings on them. Also,
It can also be used as is for inari sushi.

(5) Actions and Effects The starch in waxy rice is composed of 100% amylopectin, while the starch in glutinous rice is about 80% amylopectin and about 20%.
It is composed of amylose.

The difference between amylopectin and amylose is in their molecular structure, and this difference becomes noticeable when starch retrogrades. That is, in the case of amylopectin, it is difficult to age, and even if it is aged, it is easily regelatinized by heating, whereas in the case of amylose, it is easy to age, and even more aged, the H weave is strong and it is easily regelatinized. There is a characteristic that it does not.

This characteristic affects the suitability for frozen storage of cooked rice, and in the case of sticky rice, it is frozen at -25°C to -30°C in a freezer at 15°C.
Even if the rice is thawed naturally at room temperature, it returns to its original state, whereas cooked rice becomes cloudy, loses its viscosity, and becomes crumbly and unfit to eat.

As described above, the taste of Uruchi rice changes over time even when stored normally due to aging, and furthermore, when stored frozen, it becomes cloudy, loses viscosity, becomes crumbly, and becomes unedible.

2) Therefore, the present inventor has found that adding an inorganic salt or an organic salt shell is effective in freezing boiled rice to prevent aging.

To arrive at this invention, water was added to urchi rice flour to make it 15% by weight, then 2% by weight of inorganic salts and organic salts were added and heated to 80'C above the gelatinization temperature. After natural cooling, it was frozen in a freezer at -25°C and 48 hours later, thawed at 5°C. The control (no additives) became cloudy and had no viscosity, whereas the samples containing salt, baking soda, we sodium, sodium metaphosphate, etc. Although some of the products to which salt shells were added were slightly cloudy, they had sufficient viscosity. In particular, common salt and sodium metaphosphate were transparent and showed remarkable anti-aging effects. From this, it was found that the addition of inorganic salts and organic salts such as common salt, sodium bicarbonate, sodium #chloride, and sodium metaphosphate was effective in preventing aging of cooked rice.

Therefore, table salt and sodium metaphosphate, which are particularly effective among these salts, are added to raw rice and cooked, and after the rice is cooked, a combination of vinegar, sugar, salt, and seasonings is added to make it for sushi rice. After cooling, the mixture was molded into a 23 g sushi rice ball using a molding machine and frozen in a freezer at -25°C. After freezing, they were stored at -18°C or below and thawed naturally at room temperature of 15°C after 10 days and 1 month, and both were transparent, viscous, chewy, and flavorful enough to be used as sushi rice. . In addition, the rice thawed in 50°C warm water had good texture, taste, and flavor similar to regular sushi rice, even though it was frozen rice.

On the other hand, raw rice that does not contain inorganic salts or organic salts during cooking becomes hard, cloudy, and loses viscosity.Furthermore, even when thawed in hot water at 50°C, it remains hard and loses its transparency, making it unsuitable for use as sushi rice. Ta.

In this way, frozen rice suitable for sushi rice can be thawed naturally or in warm water at a temperature below the gelatinization temperature of starch, and even though it is frozen rice, it has the same flavor and texture as regular rice. The fact that it has good taste means that it can be easily used not only for general household use but also for commercial purposes such as restaurants and mass retailers where large quantities are consumed. Further, it does not require a U heat container, and furthermore, it prevents subtle changes in taste due to volatilization of vinegar. In addition, the freezing method can be produced in a normal freezer at -25°C and is simpler than freezing with liquid nitrogen.

(6) Examples Examples of this invention will be described.

Example 1 Rice 6.0Kg Water 9.0Kg Salt Log Sodium metaphosphate Log Structure #
850 ml sugar 6
80g Salt 230g Seasoning Add vinegar of the composition above and make sushi rice, and after cooling, 2
It is formed into 3 g of shari balls for nigiri sushi, packed in a container, and frozen in a -25°C freezer with human milk.

After 10 days of freezing, Sharidama stored at -18℃ or lower,
After 1 month, the rice was thawed naturally at a room temperature of 15°C, and was transparent, viscous, chewy, and tasteful enough to be used as sushi rice.

In addition, the rice thawed in 50°C warm water had good texture, taste, and flavor similar to regular sushi rice, even though it was frozen rice.

Therefore, by adding wasabi to the defrosted rice balls and placing sushi toppings on them, nigiri sushi can be easily obtained. It can also be used as is for inari sushi.

Example 2 (control) Rice 6.0Kg Water 9.0Kg Shuzo vinegar was added to the rice cooked without adding salt using the above composition.
850ml sugar
680g Salt 230g Seasoning Add vinegar with a composition that is more than occlusive, make sushi rice, and after cooling, 2
Shape into 3 g of Sharidama for nigiri sushi, package it in a container, and place the dough in a -25°C freezer to freeze.

After 10 days, Sharidama stored at -18℃ or lower after freezing, 1
All of the rice that was naturally thawed at room temperature of 15°C after a month of heating became hard and cloudy and lost its viscosity, and even when thawed in hot water of 50°C, it became hard and lost its transparency, making it unsuitable for use as sushi rice.

Claims (1)

[Claims] 1. A method for producing frozen cooked rice suitable for sushi rice, characterized by adding salt to raw rice and cooking the rice. 2. Claim 1, wherein the salt is an inorganic salt. 3. A method for producing frozen cooked rice according to claim 1, wherein the salt is an organic salt.