JPH0387153A - Packed processed rice preservable for long period and its production - Google Patents

Abstract

PURPOSE:To obtain the title processed rice to be boiled by adding a proper amount of water as it is without requiring water washing and water immersion by hermetically sealing rice adjusted to a specific pH and water content, heating under a specific condition, cooling, allowing to cool, grinding rice grain lump and granulating. CONSTITUTION:Rice having lowered pH3.5-6 and 20-35% water content is hermetically sealed, heated at 80-110 deg.C for 5-60 minutes, cooled and allowed to stand, rice grain lump is ground and granulated to give the objective processed rice.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a processing method that is insoluble when washed or immersed in water, can be cooked by adding i8 amount of water as it is, and can be kept for a long time at room temperature. It's about rice.

(Conventional technology) When cooking rice, for processed rice that does not dissolve when washed or soaked in water and can be cooked by adding an appropriate amount of water, there are methods of steaming and drying water-soaked rice and sealing water-soaked rice. A method of packaging and high-temperature sterilization is known (e.g., JP-A-55-102364), as well as JP-A-63-50977 and JP-A-63.
-105646 methods are known.

In Japanese Patent Publication No. 63-50977, water-soaked rice is sealed in a bag together with an oxygen absorber, subjected to high-frequency treatment, and heated with fluid from outside the bag to maintain the same temperature inside the bag. Japanese Unexamined Patent Publication No. 6.3-105646 discloses a packaging sterilization method for processed rice in which water-soaked rice is irradiated with microwaves in a sealed container and the surface is vacuum-dried.

(Problems to be Solved by the Invention) None of the conventional methods for producing packaged rice can satisfy both organoleptic properties and storage stability. In other words, dry pregelatinized rice or water-soaked rice that is sealed and packaged and sterilized at high temperatures has a good shelf life but poor taste and texture. It has the following drawbacks.

In addition, in JP-A No. 63-105646, it is reported that heat sterilization level is insufficient to sterilize heat-resistant bacteria, and that after surface drying of rice, the rice is filled and sealed and processed into packaged processed rice, which is contaminated with microorganisms. It has the disadvantages of being easily damaged and having poor storage stability.

(Means for Solving the Problems) As a result of repeated research on quick-cooking rice that can be stored for a long period of time and has good taste and texture, the inventor has found that the pH of rice is 3.

5-6, a packaged quick-cooked rice that can be stored for a long time and is characterized by having a moisture content of 35-47%, being heat-treated and made into single grains, and having a pH lowered to 3.5-6. , and rice with a moisture content of 35 to 47% is sealed and packaged, with a moisture content of 80 to 1
We have already invented a method for producing packaged quick-cooked rice that can be stored for a long time, which is characterized by heating it at 10"C for 5 to 60 minutes, leaving it to cool, and then crushing the rice grain agglomerates into single grains. A patent application was filed (Japanese Patent Application No. 1-188968).

As a result of further study, the present inventor found that rice with a moisture content of 35 to 47% as in the above invention can be cooked in about 10 minutes, but when the moisture content is less than this, it takes longer to cook rice, and with a moisture content of 20%. If it is less than 35%, it will take about 2 hours to cook rice.
It takes about 0 minutes, but if you take this amount of time, it will be cooked to a fluffy texture, so for applications that do not require very fast cooking, even foods with a moisture content of 20% or more and less than 35% can be stored for a long time. It was discovered that the rice can be packaged and processed, and the present invention was completed.

That is, in the present invention, rice has a pH of 3.5 to 6 and a moisture content of 20%.
It is a packaged processed rice that can be stored for a long time and is heat-treated and made into single grains, and has a pH lowered to 3.5 to 6, and Rice with a moisture content of 20% or more and less than 35% is sealed and packaged at 80%
Long-term storage is possible by heating at ~110°C for 5 to 60 minutes, leaving it to cool, and then crushing the rice grain agglomerates into single grains, or adding freezing and thawing treatment at this time. This is a method for producing packaged rice.

The present invention will be explained in detail below.

The raw material rice of the present invention is polished rice obtained by polishing brown rice, and is usually used after washing the rice to remove adhering bran and impurities.

The moisture content of the packaged rice of the present invention is 20% or more and less than 35%, preferably 26% or more and less than 35%. moisture is 2
If it is less than 0%, it will take a long time to cook, which is undesirable.
Usually, the moisture content obtained by soaking raw rice is less than 35%. The moisture content is determined by drying at 105°C for 14 hours and determining the loss on drying at this time.

The pH of the packaged rice of the present invention is 3.5 to 6, preferably 3.7 to 5.7. Lowering the pH of rice improves its shelf life, but if the pH is less than 3.5, the texture of the rice grains will be impaired, and if it exceeds pH 6, there will be little improvement in the shelf life. To measure pH, add the same weight of distilled water to rice,
Homogenized at 0000 rpm for 5 minutes.

The heat treatment of the packaged rice of the present invention is a process in which rice starch is heated to change it into a gelatinized state, but since gelatinized starch changes over time, it is not possible to use a 100% gelatinized state. I'm not saying that.

Furthermore, the term "single grain state" as used in the present invention refers to a state in which the surfaces of the rice grains are not bonded to each other, and the rice grains are separated and scattered.

Next, the manufacturing method of the present invention will be explained.

After removing the bran and impurities, the pH of the rice is first lowered to 3.5-6, and the moisture content is reduced to 20% or more and less than 35%, but the order of pH adjustment and moisture adjustment is as follows: ,
They may be set as appropriate, and they can be set at the same time.

The pH adjustment process can be carried out by immersing the rice in an organic acid solution made of one or a combination of edible organic acids or edible organic salts such as citric acid and malic acid, or by spraying the rice with an organic acid solution. The pH of rice may be adjusted to 3.5 to 6 depending on the method.

In the moisture adjustment treatment, rice is soaked in water below its gelatinization temperature, usually at room temperature, to increase the moisture content of the rice to 20% or more and less than 35%. It should be noted that immersion at room temperature is preferable if an organic acid solution is used instead of water, since pH adjustment treatment can be achieved at the same time and the manufacturing process can be simplified.

In sealingly packaging rice with adjusted pH and moisture as described above, a heat-resistant plastic pouch or a plastic pouch containing an aluminum layer may be used as the package, and the rice is filled into this pouch and air is removed. Keep it sealed.

Sealed and packaged rice is sterilized by heating at 80-110°C for 5-60 minutes, but at temperatures below 80°C it takes too long to reduce the number of bacteria, so heating above 110°C is not recommended. This is undesirable because the rice is exposed to high temperatures, which causes discoloration of the rice grains, development of off-flavors, and changes in texture. Heating may be performed using a retort pot or the like.

After the heat sterilized rice is left to cool, force is applied from above the package to break up the rice grain agglomerates and make them into single grains. After decreasing,
This can be done with a roller, etc.

This single flow process can be easily performed by adding and mixing oil or fat or an emulsion to rice. Edible oils such as soybean oil and rapeseed yuzu can be used as the oil, and the amount added is 1% by weight based on rice.
It is effective to use less than 1% by weight, but if the rice is used for purposes such as pilaf, it may be added in an amount of 1% by weight or more. The addition of oil and fat also has the effect of preventing rice from boiling over during cooking. Addition and mixing of fats and oils or emulsions may be performed after the pH adjustment treatment and the moisture adjustment treatment.

At this time, if you freeze and thaw the rice, you will get a softer texture when cooking, so you can do this if necessary. Alternatively, it may be carried out after the rice grain agglomerates are crushed and made into single grains, or during the process before being made into single grains.

The processed rice obtained according to the present invention can be used to cook white rice, red rice, cooked rice, fried rice, pilaf, etc. in a short time in a pot, pot, rice cooker, oven, microwave, etc. In addition, by processing liquids such as soup stock and ingredients into cooked foods such as retort foods, and combining this with processed rice, it is possible to prepare rice dishes in a short time and provide instant rice dishes that can be stored for long periods at room temperature. .

(Effect of the invention) The processed rice obtained by the present invention has the following effects.

(A) Since the rice grains are single grains, they are easily transferred from the pouch to cooking utensils, and water absorption and heating are performed uniformly during cooking.

(B) Because the rice grains have been pre-gelatinized, they can be easily cooked with various cooking utensils to a desired texture in a shorter time than when cooking raw rice.

(C) Since the rice is heated at 110° C. or lower after the package is sealed, there is no discoloration of the rice grains, no development of off-flavors, and no change in texture, and the taste and texture after cooking are almost the same as those obtained by cooking raw rice.

(D) After the package is sealed, it is heated at 80 to 110°C and the pH of the rice is low, so its quality is maintained for more than 6 months at room temperature.

(Example) Examples and test examples showing the effects of the present invention are shown below.

Example 1 2 kg of polished non-glutinous rice with a moisture content of 14.5% was washed and
．． It was immersed in 125% citric acid solution 4i for 2 hours. After draining, 20% soybean oil, 0.5% sig sugar fatty acid ester,
25 g of an emulsion containing 79.5% water was added and mixed. The moisture content had increased to 31.0%. Each 115 g of rice was sealed in a 130 mm x 170 mm pouch made of polyethylene and nylon, heated in a retort pot at 100'C under pressure for 20 minutes, and cooled with water. The next day, a cylindrical wooden rod was rolled over the pouch to break up the rice grain clumps and produce processed rice. The pH of the rice was 4.9.

Example 2 5 kg of polished non-glutinous rice with a moisture content of 14.5% was washed and
．． It was immersed in 10f of 1% citric acid solution for 3 hours. After draining, 20% soybean oil, 0% sucrose fatty acid ester. 5%,
50 g of an emulsion containing 79.5% water was added and mixed. The moisture content had increased to 31.5%. Place the rice in a 130mm x 170mm pouch made of polyethylene and nylon.
Each 15 g portion was sealed and heated in a retort pot at 100° C. under pressure for 15 minutes, and cooled with water. The next day, a cylindrical wooden rod was rolled over the pouch to break up the rice grain clumps and freeze them. After 5 days, it was thawed to produce quick-cooked rice with a pH of 5.0.

Test Example 1 (Evaluation of Cooked Rice) 180 g of the processed rice of Example 1 was placed in a pot, and 250 g of water was added. It was heated on a gas stove for 15 minutes and tasted unevenly for 5 minutes.

The rice was cooked evenly throughout, with no core remaining in the rice grains, and the taste and texture were almost the same as raw rice cooked in a rice cooker as usual.

Test Example 2 (Storage Evaluation) The quick-cooked rice of Example 1 was stored at 25°C, and after 2.4° and 6 months, the number of viable bacteria was examined. The taste and texture after cooking the rice were also good.

Claims (3)

[Claims] (1) A packaged rice that can be stored for a long time, characterized in that the rice has a pH of 3.5 to 6, a moisture content of 20% or more and less than 35%, has been heat-treated, and has been made into single grains. (2) Lower the pH to 3.5-6 and reduce the water content to 20
% or more and less than 35% rice is sealed and packaged, and the rice is 80-110%
A method for producing packaged rice that can be stored for a long period of time, which comprises heating the rice at a temperature of 5 to 60 minutes, leaving it to cool, and then crushing the rice grain agglomerates into single grains. (3) Lower the pH to 3.5-6 and reduce the moisture to 20
% or more and less than 35% rice is sealed and packaged, and the rice is 80-110%
A method for producing packaged rice that can be stored for a long period of time, which comprises heating at 5 to 60 minutes at a temperature of 0.degree.