JP2004173587A - Method for disinfecting cooked rice or rice product processed by steps involving heat-treating step - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effectively disinfecting a cooked rice or a rice product processed by steps involving a heat-treating step, elementally without using a chemical treatment using chemicals and hardly developing fear of causing deterioration of the quality of the rice. <P>SOLUTION: The method for disinfecting the cooked rice or the rice product processed by the steps involving the heat-treating step involves carrying out a treatment for bringing a raw material rice into contact with an alkaline aqueous solution, and a treatment for soaking the treated rice in a strong acidic water before cooking the rice or heat-treating the rice. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for sterilizing cooked rice or processed rice including a heat treatment step, and more particularly to a method for effectively sterilizing cooked rice or processed rice including a heat treatment step without causing quality deterioration. .
[0002]
[Prior art]
When cooking or processing rice to produce cooked rice or processed rice, the rice is immersed. Usually, in rice immersion treatment, it is difficult to perform chemical treatment using chemicals as non-heat sterilization treatment because rice itself absorbs water used, and storage at room temperature is possible In processing, it has been general to perform a sufficient heat treatment.
[0003]
However, if the heat treatment is sufficiently performed by heating at a high temperature exceeding 130 ° C., the heat-resistant spores which may be mixed before the heat processing can be sterilized, but the quality deterioration of the rice due to the high temperature heating is reduced. May occur.
[0004]
Therefore, there is a need for a method of effectively sterilizing cooked rice or a processed rice product including a heat treatment step, which is not a chemical treatment using a chemical, and has no risk of deterioration of rice quality.
[0005]
By the way, it is known that an acidic aqueous solution on the anode side generated by electrolytically treating a diluted saline solution through a diaphragm has a sterilizing ability (for example, see Patent Document 1).
However, in this case, depending on the object, there may be a case where the bactericidal effect is not sufficiently obtained, and the odor of available chlorine, which is a main component exhibiting the bactericidal effect in acidic water, and the low pH of the solution (pH 1.5-3. From 1), the quality of the processed product may be reduced. In particular, in the case of rice which is an object of the treatment of the present invention, such a tendency was remarkable.
[0006]
[Patent Document 1]
Patent No. 2662678 [0007]
[Problems to be solved by the invention]
The present invention is intended to solve such conventional disadvantages, and is not basically a chemical treatment using chemicals, and furthermore, there is no fear of causing deterioration of rice quality, and rice cooked rice or heat treatment can be effectively performed. It is an object of the present invention to provide a method for sterilizing a processed rice product including a process.
[0008]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned conventional problems. As a result, it was surprisingly found that prior to rice cooking or heat treatment, the raw rice was subjected to contact treatment with an alkaline aqueous solution and immersion treatment in strongly acidic water, thereby achieving the object, and based on this finding. Thus, the present invention has been completed.
[0009]
That is, the present invention according to claim 1 is a method for sterilizing a processed rice product including a cooked rice or heat treatment step, wherein the raw rice is contacted with an alkaline aqueous solution and immersed in strongly acidic water prior to the rice cooking or heat treatment. It is intended to provide a method for sterilizing cooked rice or processed rice, which is characterized by performing a treatment.
According to a second aspect of the present invention, the alkaline aqueous solution is an alkaline ionized water obtained by an electrolyzed water generator without salt, a strongly alkaline water or a sodium hydroxide solution obtained by an electrolyzed water generator with salt added. , A method according to claim 1.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described.
The present invention according to claim 1 relates to a method for sterilizing cooked rice or processed rice, and in a method for sterilizing cooked rice or processed rice including a heat treatment step, prior to cooking or heating, the raw rice is treated with an alkaline aqueous solution. The contact treatment and the immersion treatment in strongly acidic water are performed.
[0011]
The present invention according to claim 1 relates to a method for sterilizing cooked rice or processed rice including heat treatment.
Cooked rice which is one object of the present invention according to claim 1 is usually produced by heating raw rice immersed in water. Another object of the present invention according to claim 1 is a processed rice product including a heat treatment process, for example, a processed rice cake and rice flour confectionery which are Korean traditional foods. As described above, the present invention according to claim 1 includes the heat treatment step. The present invention according to claim 1 effectively sterilizes heat-resistant bacteria (such as heat-resistant spores) that cannot be sterilized even through such a normal heat treatment step.
[0012]
In the present invention, prior to the rice cooking or heating treatment, the raw rice is subjected to a contact treatment with an alkaline aqueous solution and a dipping treatment with strongly acidic water. Here, as the raw rice, since the sterilization effect is not sufficient if the rice is in a state where rice husks are attached, a rice from which rice husks have been removed (brown rice) or a rice milled state (milled rice) is used. .
As the alkaline aqueous solution, various ones can be mentioned, and there is no particular limitation. However, as described in claim 2, the alkaline ionized water obtained by the electrolyzed water generation device without salt, the electrolyzed water generation device with salt added, The resulting strongly alkaline water or sodium hydroxide solution is preferred.
Here, as the alkaline ionized water obtained by the electrolyzed water generating apparatus without salt and the strongly alkaline water obtained by the electrolyzed water generating apparatus with added salt, those obtained by a known electrolyzed water generating apparatus can be used. .
The pH of the strongly alkaline water is not particularly limited, but usually, a pH of about 10 to 12 is used.
[0013]
The contact treatment with an alkaline aqueous solution is performed in combination with a sterilization treatment by immersion treatment in strongly acidic water, and the treatment itself hardly provides a sterilization effect. In this sense, the process can be said to be a preliminary process. However, a remarkable sterilizing effect and a quality deterioration suppressing effect can be obtained by combining with a sterilizing treatment by immersion treatment in strongly acidic water.
[0014]
As a method of the contact treatment with the alkaline aqueous solution, there are methods such as washing and immersion. Usually, a lighter treatment is sufficient, and a washing time of about 5 minutes is sufficient. . In the case of immersion, even if it is immersed for an excessively long time, the bactericidal effect and the like are not improved. Therefore, the immersion is preferably performed for at most about 30 minutes. The time of the contact treatment with the alkaline aqueous solution may be appropriately adjusted according to the material and the like. Similarly, the amount of the alkaline aqueous solution used in the contact treatment may be appropriately adjusted according to the material and the like.
[0015]
According to the first aspect of the present invention, it is necessary for the raw rice to be subjected to the contact treatment with the alkaline aqueous solution as described above and to the immersion treatment with the strongly acidic water.
The contact treatment with the alkaline aqueous solution and the immersion treatment with the strongly acidic water need to be performed in this order in order to exhibit a sterilizing effect. However, if necessary, pre-sterilization can be performed by treating with a strong acidic water prior to the contact treatment with the alkaline aqueous solution, or contact treatment with the alkaline aqueous solution again after the immersion treatment with the strong acidic water. By doing so, dirt can be removed.
[0016]
Examples of the strongly acidic water used for the immersion treatment in the strongly acidic water include strongly acidic water (strongly acidic electrolyzed water) obtained by using an electrolyzed water generator with or without the addition of a water-soluble ionizable inorganic substance (eg, salt). Can be That is, in general, an acidic aqueous solution containing hypochlorous acid (strongly acidic electrolyzed water) generated on the anode side by electrolyzing a dilute saline solution is exemplified.
The pH of the strongly acidic water is not particularly limited, but a pH of about 2.2 to 2.7 is generally used so that the acidity is not too strong.
[0017]
The time of the immersion treatment in the strongly acidic water may be about one hour, but generally about 30 minutes suffices. The time of the immersion treatment in the strongly acidic water may be appropriately adjusted according to the material and the like. Similarly, the amount of strongly acidic water used in the immersion treatment may be appropriately adjusted according to the material and the like.
[0018]
It is preferable to perform a washing treatment with distilled water before or after the pre-contact treatment with the alkaline aqueous solution and the immersion treatment with the strongly acidic water.
Washing with distilled water is generally sufficient for about 5 minutes, but may be performed for about 30 minutes.
[0019]
After performing the preliminary contact treatment with the alkaline aqueous solution and the immersion treatment with the strongly acidic water in this way, the cooked rice or cooked rice product can be manufactured by cooking or heating.
The cooking or heating treatment may be performed by a conventional method, and the processing conditions may be the same as the processing conditions in the conventional method.
[0020]
The cooked rice or processed rice product thus produced is not only effectively sterilized by heat-resistant spores that may be mixed before the heat treatment, but also does not need to be subjected to a remarkably high-temperature heat treatment. In addition, there is no possibility that the quality of rice is deteriorated by the treatment.
[0021]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.
[0022]
Example 1
As the test rice, commercially available polished rice (Koshihikari from Ibaraki, 2001) was used.
The test water was distilled water (indicated as D / W or Distilled Water in the figure) and strong acid electrolysis obtained by subjecting tap water to electrolytic treatment with an electrolyzed water generator (Hoshizaki Electric, ROX-20TA). Water (denoted as AcEW in the drawing) and strongly alkaline electrolyzed water (denoted as AlEW in the drawing) obtained by subjecting tap water to electrolytic treatment with an electrolyzed water generator (Hoshizaki Electric, ROX-20TA). Were used.
20 g of the polished rice was collected in a beaker of 100 ml each, 50 ml of test water was added thereto, and the mixture was stirred for 5 minutes to wash the rice.
Next, test water was newly added to the beaker, immersed for 1 hour, and then drained using a stainless steel wire mesh basket.
After draining, the pH was measured using a pH meter (manufactured by HORIBA, pH-22 D-22), and the color difference was measured using a color difference meter (CHROMA-meter CR300).
In order to improve the bactericidal effect of the electrolyzed water on microorganisms, the rice was washed and immersed in running water, and then the changes in the number of general bacteria and the number of heat-resistant bacteria were measured. The thermostable bacteria were treated at 80 ° C. for 10 minutes, then cultured and detected.
[0023]
In order to evaluate the quality of the raw rice with the test water, the pH and color difference of the raw rice were measured after washing and dipping. The results are shown in FIGS. 1 and 2, respectively. In FIG. 2, L value (L value) indicates brightness, a value (a value) indicates red, and b value (b value) indicates yellow.
As shown in FIG. 1, the pH of the raw rice is in a neutral region of about 7.1, and when treated with distilled water (D / W or Distilled Water), the change in pH is not so much observed. The pH dropped to 3.4 when immersed in strongly acidic electrolyzed water for 1 hour (AcEW), and changed to 9.4 when immersed in strongly alkaline electrolyzed water (AlEW).
On the other hand, as a combination treatment of electrolyzed water, rice is first washed for 5 minutes with strongly alkaline electrolyzed water, immersed in strongly acidic electrolyzed water for 30 minutes, and then immersed in distilled water for 30 minutes (AlEW → AcEW → D / W), the pH changed to 6.0 as shown in FIG.
This was thought to be because the electrolyzed water was absorbed by the rice during the immersion and the pH changed.
[0024]
As is clear from FIG. 2, when immersed in a single electrolyzed water, the browning of the rice was recognized by the treatment with the strongly acidic electrolyzed water (AcEW), and the rice was immersed in the strongly alkaline electrolyzed water (AlEW). Greening of rice was observed by the treatment. This was thought to be due to the discoloration of proteins and carbohydrates in the rice bran layer under the influence of pH.
However, as is clear from FIG. 2, the discoloration was not recognized by the combined treatment of the electrolyzed water as in the distilled water treatment.
From the results shown in FIGS. 1 and 2 above, it was clarified that by performing the combined treatment of the electrolyzed water (AlEW → AcEW → D / W), the pretreatment of rice was possible without deteriorating the quality. .
[0025]
Next, the results of the sterilization test are shown in FIG. In the figure, "Common-micro" indicates the number of general bacteria, and "Heat-resist" indicates the number of heat-resistant bacteria.
In FIG. 3, when A is a raw rice, and B is a cleaning treatment with strongly alkaline electrolyzed water (AlEW) having a pH of 11.7, C is a cleaning treatment performed with strongly alkaline electrolyzed water having a pH of 11.7 (AlEW). After immersion in strongly acidic electrolyzed water for 1 hour (AcEW), washing with distilled water having a pH of 6.8 (D / W), and then immersing in strongly acidic electrolyzed water for 1 hour (AcEW), E The numbers of bacteria are shown in the case where the bacteria were washed (AcEW) with strongly acidic electrolyzed water having a pH of 2.7 and then immersed in strongly acidic electrolyzed water (AcEW).
As a result of the treatment with the electrolyzed water, it was confirmed that when washed with strongly alkaline electrolyzed water and immersed in strongly acidic electrolyzed water (C in FIG. 3), the microorganism was excellent in the bactericidal effect.
This is considered to be due to changes in the appropriate growth conditions of the microorganisms due to changes in the external environment such as the electrolytic reduction effect of the electrolyzed water, the bactericidal effect of available chlorine, and a sudden pH change.
[0026]
Example 2
Distilled water was applied to the process of producing Korean-style rice cakes in order to check how much the number of bacteria mixed in rice decreased during washing and immersion. It was measured. The result is shown in FIG.
In FIG. 4, A is a raw rice, B is a cleaning treatment with distilled water (D / W) having a pH of 6.8, and C is a primary immersion in distilled water for 30 minutes (D / W). , D are then immersed in distilled water having a pH of 6.8 (D / W), E is the number of bacteria when additional materials are added and pulverized, and F is 100 ° C. , 30 minutes of heat treatment, G indicates the number of bacteria when 110 ° C. and 30 minutes of heat treatment are performed, and H indicates the number of bacteria when heat treatment is performed at 130 ° C. and 30 minutes.
[0027]
According to FIG. 4, general bacteria and heat-resistant bacteria in the raw rice do not decrease so much by performing normal washing treatment and immersion treatment using distilled water, and in the final heat processing. It can be seen that in order to sterilize spores of heat-resistant bacteria, it is necessary to perform high-temperature heat treatment at 110 ° C. for more than 30 minutes.
[0028]
Example 3
In order to compare the sterilization effect of electrolyzed water on heat-resistant spores which may be a concern during storage of rice products and to examine the sterilization more clearly, a suspension of heat-resistant spores (Bacillus subtilis) spores is spread on raw rice and then distilled water. The change in the number of viable bacteria when rice was washed and immersed using electrolyzed water was measured. In order to spread spores on rice, 100 ml of a spore solution of 10 ⁸ cfu / ml is sprayed on 200 g of raw rice, left for 10 minutes, treated with test water, washed with rice, and subjected to microbial behavior when immersed. As shown in FIG.
[0029]
In FIG. 5, A is a raw rice; B is washed with distilled water having a pH of 6.8 (D / W); C is washed with distilled water having a pH of 6.8 (D / W); When immersed in distilled water for 30 minutes (D / W); D is washed with distilled water having a pH of 6.8 (D / W), and then immersed in distilled water having a pH of 6.8 (D / W). When secondary immersed in distilled water of pH 6.8 for 30 minutes (D / W); E is a washing treatment with strongly alkaline electrolyzed water (AlEW) having a pH of 11.7; F is a strong alkali having a pH of 11.7. When immersed in strongly acidic electrolyzed water for 30 minutes after performing a cleaning process with electrolyzed water (AlEW) (AcEW); After performing a cleaning process with strongly alkaline electrolyzed water (AlEW) having G of pH 11.7, strongly acidic Immersed in electrolyzed water for 30 minutes (AcEW) and then in distilled water of pH 6.8 for 30 minutes If immersed respectively show the number of bacteria (D / W).
[0030]
According to FIG. 5, in the distilled water treatment assuming the normal treatment, the number of general bacteria and the number of heat-resistant bacteria ultimately decrease only by about one tenth to one hundredth, respectively. I understand.
On the other hand, in the method of the present invention in which the preliminary contact treatment with the alkaline aqueous solution and the immersion treatment with the strongly acidic water are performed, the number of general bacteria is about 1/1000, and the number of heat-resistant bacteria is about 1/1000, which is almost detected. This indicates that sterilization below the limit is possible.
Therefore, the method of the present invention is particularly effective for sterilizing heat-resistant bacteria, and it can be expected that the microbial safety of cooked rice and heat-processed rice can be ensured without impairing the quality by performing the method.
[0031]
【The invention's effect】
According to the method of the present invention according to claims 1 and 2, prior to cooking or heating, rice is subjected to a preliminary contact treatment with an alkaline aqueous solution and a dipping treatment with strongly acidic water to reduce the quality of rice. It is possible to effectively sterilize cooked rice or cooked rice including heat treatment without fear of causing it.
That is, the method of the present invention according to claims 1 and 2 is a non-heat sterilization treatment method, but by performing normal rice cooking or heat treatment, sterilization is performed only by performing normal rice cooking or heat treatment. It is possible to effectively sterilize heat-resistant bacteria such as heat-resistant spores that may not be able to be mixed before heating. As described above, the method of the present invention according to claims 1 and 2 does not need to perform a remarkable high-temperature heat treatment, so that there is no possibility that the quality of rice is deteriorated by the treatment.
[0032]
In addition, when acid water treatment is performed, chlorine odor lowers the palatability of rice processed by the subsequent heat treatment, and further, due to the low pH of the liquid, the quality of the processed material such as discoloration is reduced. However, according to the method of the present invention according to claims 1 and 2, the cooked rice or processed rice product obtained after cooking or heat treatment is such that the smell, color, and the like are not inferior to normal ones. There is no risk of lowering the palatability, and there is no risk of lowering the quality of the processed product such as discoloration.
Moreover, in the method of the present invention according to claims 1 and 2, the chemical components contained in the alkaline aqueous solution and the strongly acidic water used in the sterilization treatment are trace amounts, and are not basically chemical treatments using drugs. There is no worry about safety.
The present invention relates to a method for sterilizing cooked rice or a processed rice product including a heat treatment step. However, the possibility of applying electrolyzed water to agricultural products such as vegetables is considered.
[Brief description of the drawings]
FIG. 1 is a graph showing measurement results of pH in Example 1.
FIG. 2 is a graph showing measurement results of color differences in Example 1.
FIG. 3 is a graph showing the results of a sterilization test in Example 1.
FIG. 4 is a graph showing measurement results of changes in microorganisms for each step in Example 2.
FIG. 5 is a graph showing the measurement results of the number of general bacteria and the number of thermostable bacteria in Example 3.

Claims (2)

In a method for sterilizing a cooked rice or a processed rice product including a heat treatment step, prior to the rice cooking or heat treatment, the raw rice is subjected to a contact treatment with an alkaline aqueous solution and a dipping treatment with strongly acidic water. Or a method of sterilizing processed rice. The method according to claim 1, wherein the alkaline aqueous solution is alkaline ionized water obtained by an electrolyzed water generator without salt, strong alkaline water or a sodium hydroxide solution obtained by an electrolyzed water generator with salt added.

Images