JP2022066911A - Production method of rice - Google Patents

Abstract

To provide a production method of rice which is excellent in handleability, does not generate an irritating odor like an acidic smell and is odorless, is safe and efficient, and also has an excellent bacteriostatic effect for rice-derived Bacillus subtilis.SOLUTION: Rice cooking is performed where fumaric acid is added at 0.03 to 0.2 mass% relative to a total amount of a cooked product of rice. Preferably, the rice cooking is performed where at least one selected from glycerin fatty acid ester, polyglyceryl fatty acid ester, and xanthan gum is additionally added.SELECTED DRAWING: None

Description

The present invention relates to a method for producing cooked rice, and more particularly to a method for producing cooked rice having an excellent bacteriostatic effect against Bacillus subtilis derived from rice without generating a pungent odor such as an acidic odor or having an acid taste.

Conventionally, in cooked rice foods such as white rice, rice balls, and rice balls, acidulants such as acetic acid and gluconic acid and pH adjusters have been used to suppress the growth of bacteria during storage and sales from the viewpoint of thorough hygiene management. Many techniques for adding are known.

For example, 1) A method for protecting cooked rice (for example, a patent), which comprises immersing washed white rice in a 0.2 to 1.0% acetic acid solution and then heating the rice to allow the acetic acid to permeate into the center of the rice grain. (Refer to Reference 1), 2) When cooked rice is produced by adding water to rice, add an aliphatic organic acid (including this organic acid) excluding acetic acid, butyric acid and other fatty acids to set the pH to 6.5 or less. A method for producing cooked rice characterized by heating (see, for example, Patent Document 2), 3) Rice for cooking rice is dipped in an acetic acid solution to allow acetic acid to permeate the inside, and the rice after the acetic acid treatment is treated. Rice cooking is characterized by improving the quality of rice for cooking by neutralizing it with a solution containing an organic acid salt which is a food additive such as sodium citrate or sodium acetate to remove the aroma and taste of acetic acid. A quality control method for cooked rice (see, for example, Patent Document 3) is known.

The acetic acid used in the above Patent Documents 1 and 2 is excellent in terms of antiseptic power, but since it is a volatile acid, it imparts a tendency and acidity to give a peculiar pungent odor to cooked rice. In particular, when this type of cooked rice is reheated in a microwave oven or the like, there is a drawback that an acetic acid odor is generated more strongly and the flavor is deteriorated. The neutralization treatment of Patent Document 3 suppresses the generation of acetic acid odor, but there is a problem that the treatment method becomes complicated, and improvement is eagerly desired at present.

Bacillus subtilis, on the other hand, is a bacterium that exists in the soil and is ubiquitous. In particular, it is a type of putrefactive bacterium that is normally present in rice straw and is contained in the genus Bacillus. This Bacillus subtilis forms an outer skin called spores, which are resistant to heat, so they survive the heat of cooking rice (100-120 ° C), and after cooking, they start their activity and give off discoloration and smell. Or something. Moreover, troublesomely, at the stage of polished rice, it is not possible to visually confirm whether or not the rice is contaminated with these bacteria. Since the above-mentioned Bacillus subtilis is a putrefactive bacterium, it is not so harmful to the human body, but in the food service, if such discoloration or odor comes out, few people will eat it and it may cause great damage. Become.

JP-A-53-94044 (Claims, Examples, etc.) Japanese Patent Application Laid-Open No. 4-183365 (Claims, Examples, etc.) JP-A-7-250629 (Claims, Examples, etc.)

The present invention has been made in view of the above-mentioned problems of the prior art and the current state of affairs, and is intended to solve the problems. It is an object of the present invention to provide a method for producing cooked rice, which is safe and efficient and has an excellent bacteriostatic effect on Bacillus subtilis derived from rice.

As a result of diligent studies on the above-mentioned conventional problems, the present inventors examined whether fumaric acid can be used against rice-derived bacillus among the organic acids used as acidulants in foods. As a result of conducting verification tests and the like, it was found that the above-mentioned method for producing rice and rice could be obtained, and the present invention was completed.
That is, the present invention is a method for producing cooked rice, which comprises adding 0.03 to 0.2% by mass of fumaric acid to the total amount of cooked rice when cooking cooked rice.
It is preferable to add at least one selected from glycerin fatty acid ester, polyglycerin fatty acid ester, and xanthan gum together with the fumaric acid.

According to the present invention, it is easy to handle, does not feel acidity, is odorless without generating a pungent odor such as an acidic odor, is safe and efficient, and is excellent against Bacillus subtilis derived from rice. A method for producing cooked rice having a bacteriostatic effect is provided.
The object and effect of the present invention are recognized and obtained particularly by using the components and combinations pointed out in the claims. Both the general description described above and the detailed description below are illustrative and descriptive herein and are not intended to limit the invention described in the claims.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be noted that the technical scope of the present invention is not limited to the respective embodiments detailed below, but extends to the inventions described in the claims and their equivalents.
The method for producing cooked rice of the present invention is characterized in that when cooked rice is cooked, 0.03 to 0.2% by mass of fumaric acid is added to the total amount of cooked rice to cook the cooked rice.

The fumaric acid used is used as a bacteriostatic component against Bacillus subtilis derived from rice in the production of cooked rice, is represented by the structural formula [HOOC-CH = CH-COOH (trans form)], and is sparingly soluble in water. It is a crystalline powder.
The fumaric acid used is not particularly limited, but is preferably a volume average particle diameter of 30 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less, and the fumaric acid commercially available as a raw material is pulverized by a dry or wet method. Then, the one having the above-mentioned preferable particle size is used. Further, it may be used that has been crystallized and taken out so as to have a preferable particle size at the time of raw material production.

The content of fumaric acid used is 0.03 to 0.2% by mass (hereinafter, "mass%" is simply referred to as "%"), more preferably 0.03 to 0.2% by mass, based on the total amount of cooked rice. It is desirable to set it to 0.1%.
If the content of fumaric acid is less than 0.03%, the effect of the present invention may not be exhibited, while if it exceeds 0.2%, a sour taste is exhibited, which is not preferable.
In the present invention, the "total amount of cooked rice" is the total amount (100%) including rice, water, food ingredients other than rice, fumaric acid to be added, and other additive components when used for cooking rice. ) Means.

Further, in the method of the present invention, it is preferably selected from glycerin fatty acid ester, polyglycerin fatty acid ester, and xanthan gum together with the above-mentioned predetermined amount of fumaric acid from the viewpoint of improving the solubility of fumaric acid and improving the dispersibility of fumaric acid. It is preferable to add at least one kind.
These ingredients are used as food additives, and their safety has been confirmed.

The above-mentioned glycerin fatty acid ester, polyglycerin fatty acid ester, and xanthan gum are preferably the total content of fumaric acid in consideration of the poor solubility in water (solubility in water: 25 ° C., 0.63 g / 100 mL) with respect to the total amount of cooked rice. Is preferably 0.0001 to 0.05%, and more preferably 0.0005 to 0.01%.

More preferably, as fumaric acid, it is preferable to use an aqueous dispersion in which fumaric acid having a predetermined volume average particle size is dispersed in glycerin fatty acid ester, polyglycerin fatty acid ester, and xanthan gum in advance, and particularly preferably, the total amount of cooked rice is used. On the other hand, the above-mentioned predetermined amount of fumaric acid having a volume average particle diameter of 10 μm or less, xanthan gum 0.0002 to 0.002%, glycerin fatty acid ester 0.001 to 0.005%, and water used for cooking rice were used. It is desirable to use the totaled aqueous dispersion of fumaric acid.

In the method of the present invention, the rice used as a raw material for cooking rice is not particularly limited as long as it is used for ordinary rice foods, such as glutinous rice, glutinous rice, polished rice, brown rice, japonica rice, indica rice, and glutinous rice. It can be used regardless of the degree of whitening, the variety, etc., and a plurality of types of rice may be mixed and used.
Further, in the method of the present invention, when cooking cooked rice, if the cooked rice is cooked by adding 0.02 to 0.2% of fumaric acid to the total amount of cooked rice, the cooked rice method (rice cooking temperature, time, The rice cooking machine, rice cooking means, rice cooking process, etc.) are not particularly limited. can.
In addition, when producing cooked rice other than white rice, kamameshi, rice balls, red rice, etc., a raw material other than rice may be mixed with the cooked rice food raw material, or when packaging in a resin packaging film such as rice balls. In terms of releasability, edible oils and fats may be added when cooking rice. That is, in the present invention, in addition to rice, seasonings and sugars (trehalose, high fructose corn syrup, glucose, lactose, fructose) other than the above rice are used as raw materials for cooked rice. Etc.), edible oils and fats, spices, soup stock, etc. may be used.
Further, the method of the present invention may include a step of accommodating or packaging the produced cooked rice in a container or a packaging material. Such a container or packaging material may be made of a heat-resistant material capable of microwave heating. That is, the cooked rice food contained or packaged in the container or the packaging material is also within the range of the product of the rice cooking method (the method for producing the cooked rice) which is the production method of the present invention.

In the method of the present invention, when cooking cooked rice, 0.03 to 0.2% of fumaric acid is added to the total amount of cooked rice to cook the cooked rice, and more preferably, the cooked rice is cooked by the above-mentioned cooked rice method. It is desirable to cook rice so that the pH of the cooked rice is 5.0 or more, particularly preferably 5 to 6.5.
Here, when the pH of the cooked rice is 5.0 or more, the cooked rice does not feel acidity or acid odor, while when the pH of the cooked rice is 6.5 or less, the growth of germs such as Bacillus subtilis grows. It can be suppressed.
To adjust the pH range (5 to 6.5) of the cooked rice, the contents of fumaric acid and acetic acid to be used, and organic acid salts such as fumaric acid, citrate, malic acid, and lactate are added. By doing so, it can be adjusted.

As described above, the cooked rice obtained by the method of the present invention is excellent in handleability, does not feel acidity, is odorless without generating a pungent odor such as an acidic odor, is safe and efficient, and is derived from rice. It also has an excellent bacteriostatic effect on Bacillus subtilis.
The cooked rice cooked in this way is appropriately packed in a container, distributed at a low temperature, etc., and then reheated in a microwave oven or the like to be eaten. It will be.

Next, the present invention will be described in more detail with reference to Test Examples 1 to 3 below.
[Test Example 1]
Add 170 ml of water and 0.75 g of test solution sample 1 having the following composition to 150 g of rice (rice of the first year of Reiwa, variety: Yume Tsukushi rice), rice cooker (NL-B805 type (0.54 L size), Zojirushi Mahobin) Made) was used to cook rice.
10 g of cooked rice is taken, and Bacillus subtilis spores (spore-forming Bacillus subtilis: B.subtilis NBRC3134) adjusted to 300 CFU / 0.1 ml are added and stored at 25 ° C for 72 hours, and then Bacillus subtilis. The number of bacteria was measured by the pour method. The control is 100% water (purified water).
These results are shown in Table 1 below.

Test solution sample 1:
Fumaric acid (volume average particle size is 10 μm, the same applies below) 30.0%
Xanthan gum 0.2%
Glycerin fatty acid ester 0.5%
Water (purified water) 69.3%

As is clear from the results in Table 1 above, in the test solution sample 1 containing 0.07% fumaric acid, no increase in the number of Bacillus subtilis forming spores was observed over time, and the bacillus was excellent. It was confirmed that it had an effect. In the following Test Examples 2 to 3, the bacteriostatic effect of Bacillus subtilis by each concentration of fumaric acid and the sensory evaluation (sour taste, odor) were tested and evaluated. The Bacillus subtilis spores used in Test Example 1 and the Bacillus subtilis solution used in Test Example 2 and below, which will be described later, differ in whether or not they are added in a heat-resistant spore state.

[Test Example 2: Example 1 and Comparative Examples 1 to 4]
Rice cooker by adding 170 ml of water and organic acids (fumaric acid, acetic acid, citric acid, apple acid, lactic acid) of each concentration shown in Table 1 below to 150 g of rice (rice of the first year of Reiwa, variety: Yume Tsukushi rice). (NL-B805 type (0.54L size), manufactured by Zojirushi Mahobin Co., Ltd.) was used to cook rice.
Divide 10 g of cooked rice, add Bacillus subtilis solution of the following bacterial species adjusted to 10-90 CFU / 0.1 ml, store at 25 ° C for 72 hours, measure the number of bacteria, and improve shelf life. The effect was evaluated.
When the number of bacteria after storage at 25 ° C. for 72 hours was ¹⁰ to the ^5th power (105) or less, it was accepted (evaluation: ◯), and when it exceeded 105, it was evaluated as (evaluation: ×).
Regarding the taste (sour taste), five panelists were asked to eat and drink, and the sensory evaluation (when the sour taste or the pungent odor was felt: ×, when the sour taste and the pungent odor were not felt: ○) was performed.
Further, the obtained cooked rice was measured at a product temperature of 25 ° C. using a pH meter: LAQUAact (manufactured by HORIBA).
As the Bacillus subtilis derived from rice, B. subtilis NBRC3134 was used as the evaluation strain.
These results are shown in Table 2 below.

無添加：ｐＨ６．８６

Additive-free: pH 6.86

[Test Example 3: Examples 2 to 4 and Comparative Examples 1 to 4]
170 ml of water and fumaric acid having each concentration shown in Table 2 below were added to 150 g of the same rice as in Test Example 1 and cooked using the same rice cooker as in Test Example 1.
10 g of cooked rice was separated, the same Bacillus subtilis solution as in Test Example 1 above adjusted to 10 to 90 CFU / 0.1 ml was added, and the mixture was stored at 25 ° C. for 96 hours, and then the number of bacteria was measured. The shelf life improvement effect was evaluated in the same manner as in Test Example 1 above.
The taste (sour taste) and pH were evaluated in the same manner as in Test Example 1 above.
These results are shown in Table 3 below.

As is clear from the results of Tables 1 to 3 above, it can be confirmed that the optimum blending amount of fumaric acid is 0.03 to 0.20%, and the concentration is less than 0.03%. The shelf life effect could not be exhibited, and when it became 0.23% or more, the acidity was felt.
As a result, by using fumaric acid at a predetermined concentration within the scope of the present invention, it is easy to handle, has no acidity, is odorless without the generation of pungent odors such as acidic odors, is safe and efficient, and is derived from rice. It was found that cooked rice having an excellent bacteriostatic effect on Bacillus subtilis can be obtained.

Cooked rice that is easy to handle, does not feel acidity, is odorless without the generation of pungent odors such as acidic odors, is safe and efficient, and has an excellent bacteriostatic effect against Bacillus subtilis derived from rice. Manufacturing method is provided.

Claims (2)

A method for producing cooked rice, which comprises adding 0.03 to 0.2% by mass of fumaric acid to the total amount of cooked rice when cooking cooked rice. The method for producing rice rice according to claim 1, further comprising adding at least one selected from glycerin fatty acid ester, polyglycerin fatty acid ester, and xanthan gum.