JP2808060B2 - Method for producing retort cooked rice with improved flavor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing retorted cooked rice having an improved flavor, and more particularly, to reliably prevent oxidation of components in rice grains, particularly oil and fat components, during retort treatment. Accordingly, the present invention relates to a method for producing retort cooked rice having an improved flavor, in which generation of an off-odor peculiar to retort cooked rice and deterioration of flavor are surely suppressed.

[0002]

2. Description of the Related Art Conventionally, as various retort foods have been developed, attempts have been made to produce retort products of cooked rice, and various retort cooked rice have been developed, and various products have been proposed so far. .

[0003] In general, retort cooked rice has been produced by filling a container with normal cooked rice which has been completely cooked in advance, sealing the container, and then subjecting the container to retort sterilization. Due to this, various components contained in the rice grains are deteriorated, and especially the fats and oils components in the rice grains are oxidized, which causes the generation of unusual smell peculiar to retort cooked rice and the deterioration of flavor, and reduces the commercial value of retort cooked rice There is a problem that it is difficult to produce retort cooked rice having a remarkably reduced flavor and good flavor.

[0004] In order to solve the above problems, the present inventors have studied various methods so far.
For example, as disclosed in JP-A-3-236753,
A method has been developed in which a container such as cooked rice is filled and sealed with an oxygen scavenger made of a chemical agent, oxygen is removed from the headspace, and then retort sterilization is performed. However, in the above method, although the intended purpose can be achieved, it is necessary to maintain a specific temperature range controlled above room temperature for a certain period of time after the encapsulation of a chemical oxygen absorber to remove oxygen from the headspace. There is
The manufacturing process has been relatively complicated, such as the need to set specific conditions for that purpose.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned situation concerning retort foods, the present inventors have made the above-mentioned conventional method of producing retort cooked rice using an oxygen scavenger composed of a chemical agent. Develops new retort food flavor improvement technology that simplifies complicated manufacturing processes and effectively prevents the deterioration of ingredients in rice grains, especially the generation of off-flavors and flavor deterioration due to oxidation of fats and oils. The research started with the goal of doing.

[0006] Regarding the mechanism of generation of off-flavor and flavor deterioration of retort cooked rice, these phenomena are as follows.
By retort sterilizing cooked rice under high temperature of 00 ° C or higher, components in rice grains that do not occur during normal cooking, especially,
It is considered that the oxidation of the oil and fat component occurs to generate a volatile carbonyl compound (such as hexanal), which is an off-flavor-causing substance.

[0007] The fats and oils in the rice grains are distributed in the cell membrane and the aleurone layer in the polished rice, and are not in direct contact with the air. 1.2
Since the rice grain structure is sufficiently swelled containing water up to 1.5 times the amount of water, it is considered that the fats and oils in the rice grain are in a state of being easily surrounded by water or in contact with water. Therefore,
It is considered that the oxidation of the components in the rice grain, particularly the fat component, is caused by the supply of oxygen from water around the fat component.

[0008] The present invention is based on the premise of the above, by removing oxygen dissolved in water used for rice cooking before cooking and maintaining the state free of dissolved oxygen until the retort treatment, by the retort treatment. This is based on the knowledge that oxidation of components in rice grains, particularly oil and fat components, can be effectively prevented.

[0009] That is, the oxygen absorber conventionally used usually requires complicated temperature control such as requiring constant temperature conditions and a long reaction time for the reaction, and the oxygen absorber itself is not directly used. When it comes into contact with cooked rice, there is a risk that the flavor of cooked rice may be degraded, and the like.Therefore, there is no such problem, and the method is simple and reliable. As a result of intensive research aimed at developing a new technology that can reliably prevent the oxidation of the fat component, using glucose oxidase and glucose, by simultaneously performing sterilization and cooking by retort treatment, The inventors have found that the initial object is achieved, and have completed the present invention.

An object of the present invention is to provide a method for producing retort cooked rice having an improved flavor, wherein sterilization and cooking are simultaneously performed by retort treatment. In addition, the present invention, the generation of off-odor peculiar to retort cooked rice
It is an object of the present invention to provide a method for producing retort cooked rice in which flavor deterioration is surely suppressed and flavor is improved.

Further, the present invention provides a method for producing retort cooked rice having an improved flavor which can be easily produced simply by adopting a series of ordinary retort cooked rice production steps without requiring any special complicated steps. The purpose is to provide.

Further, the present invention provides a high-quality retort cooked rice product obtained by such a production method, in which the generation of an unusual odor peculiar to conventional retort cooked rice and deterioration of flavor are surely suppressed. It is intended to do so. Still another object of the present invention is to provide a retort cooked rice flavor improver for producing a retorted cooked rice having an improved flavor, in which generation of off-flavor and deterioration of flavor are surely suppressed. .

[0013]

The structure of the present invention for achieving the above object comprises the following technical means (1) and (2).

(1) Glucose oxidase and glucose are added to a mixed system consisting of rice and water required for cooking rice.
A method for producing retort cooked rice with improved flavor, comprising dissolving , filling in a container, sealing and holding for a time required for the enzymatic reaction, and simultaneously performing sterilization and cooking by retort treatment.

(2) The added amounts of glucose oxidase and glucose are 0.01
The method for producing retorted cooked rice with improved flavor according to the above (1), wherein the content is from 0.1 to 0.2% by weight and from 0.01 to 0.4% by weight.

Next, the configuration of the present invention will be described in detail. The rice in the present invention refers to polished rice and rice that has been washed, immersed, and drained in a conventional manner, or rice that has been steamed in advance as a pretreatment after draining. The steaming process in this case is steaming with normal pressure steam for about 3 minutes. By steaming in this manner, the water absorbency of the rice is increased, and the rice is cooked more plumply during retort sterilization. Therefore, steamed rice is preferably used as a pretreatment. In addition, the amount of water required for cooking rice is the same amount as used when cooking rice in a general household, and usually, the amount of 1.2 to 1.5 times the weight of milled rice is used. used.

In the present invention, a mixed system comprising the above rice and an amount of water necessary for cooking rice (hereinafter simply referred to as a mixed system)
The reason why glucose oxidase and glucose coexist is that glucose oxidase, which is a deoxygenase, and glucose, which is a substrate thereof, are dissolved in water to react with the enzyme to remove dissolved oxygen in the water. Furthermore, through water absorbed by rice grains,
This is because oxygen contained in water in the rice grains is also removed.

When glucose oxidase and glucose are allowed to coexist in the above mixed system, it is preferable to dissolve glucose oxidase and glucose in an amount of water necessary for cooking rice and then add them to rice. Any method may be used as long as it can coexist, and is not particularly limited.

Furthermore, the glucose oxidase and glucose may be coexistent in the mixed system before filling and sealing in a container, and the stage of adding them is not particularly limited. As the glucose oxidase and glucose used in the present invention, it is possible to use an appropriate one such as a commercial product, and it is not particularly limited.

In the present invention, the amount of glucose oxidase and glucose added is such that 1 g of glucose oxidase is
Assuming that a substance having an activity of absorbing 14.29 mg of oxygen per minute at 0 ° C. and oxidizing glucose to gluconic acid is used, based on the total weight of the mixed system,
0.01-0.2% by weight and 0.01-0.
The range of 4% by weight is preferable in that the flavor of the finished retort cooked rice is good, and 0.05 to 0.075 respectively.
% By weight and in the range of 0.1 to 0.15% by weight are more preferred.

When the amounts of glucose oxidase and glucose are below the above-mentioned ranges, it is difficult to achieve the intended purpose.
In the case of glucose oxidase, an acid odor peculiar to the enzyme is strongly sensed, which is not preferable. In the case of glucose, a caramel-like odor is strongly sensed, which is not preferable.

As described above, glucose oxidase and glucose both have these disadvantages that occur during high-temperature heat treatment, and thus, generally, it has been generally considered difficult to use them in the case of heated foods. In view of the above, it is quite unexpected to use these in the case of products that require a high-temperature heat treatment such as retort cooked rice and in which an extremely delicate flavor is important.

The material of the container in the present invention must be a material that does not allow oxygen to permeate in order to maintain a deoxygenated state, and at the same time, must be able to withstand the high temperature during the retort treatment. Any suitable one can be used as long as it satisfies the conditions, and there is no particular limitation.

Specific materials for the container include, for example, aluminum, PVDC (polyvinylidene chloride), Eval, P
VA (polyvinyl alcohol), PAN (polyacrylonitrile), PET (polyethylene terephthalate),
PP (polypropylene), NY (nylon) and the like can be mentioned, and these laminated materials are suitably used. Examples of the form of the container include a tray and a pouch.

[0025] Glucose oxidase and glucose are allowed to coexist in the mixed system, filled in the above-mentioned appropriate container, sealed, and then kept for a time necessary for the enzymatic reaction.
Usually, the holding time of about 15 minutes is sufficient, and the holding temperature is room temperature, that is, about 25 ° C. As described above, after sufficiently reducing the dissolved oxygen concentration by maintaining the time necessary for the enzyme reaction, the retort treatment is performed by a conventional method, and sterilization and cooking are performed simultaneously, whereby the retort cooked rice of the present invention having improved flavor is provided. Is manufactured. The retort treatment in the present invention is performed according to a usual method, for example, at 100 to 130 ° C. for about 30 to 1 minute. When most of the oxygen in the head space is removed by an oxygen scavenger or replacement with nitrogen, the cooked rice is discolored by the retort treatment unless the pH is adjusted. However, in the present invention, the oxygen concentration in the head space is
Since it does not become so low, there is no particular need for pH adjustment.

As described above, according to the present invention, compared to the conventional retort cooked rice cooked in a retort container and cooked rice cooked in a retort container, the enzymatic reaction is performed in the container at the stage of milled rice. The intended purpose can be achieved by treating, retorting, sterilizing and cooking rice at the same time, and in this respect, the present invention is essentially similar to conventional retort cooked rice. Is different.

Next, the specific effects of the present invention will be verified based on experimental examples. Experimental Example 1 Measurement of Dissolved Oxygen Concentration In the present invention, after the mixed system, glucose oxidase and glucose are filled in a container and sealed, oxygen is required to react with glucose and be consumed by enzymatic reaction. For a long period of time, we experimented with a model system to determine how long it would be sufficient.

In this experiment, the dissolved oxygen concentration was 8.2 PPM.
, The enzyme reaction was carried out at room temperature (25 ° C.) by appropriately changing the ratio of glucose oxidase to glucose. Then, the remaining dissolved oxygen concentration (PPM) 15 minutes after the addition of these was measured using a HORIBA D
The measurement was performed using O METER DO-8F type (manufactured by Horiba, Ltd.). The results are shown in Table 1.

[0029]

[Table 1]

The optimum temperature of the glucose oxidase used in this experiment is 30 to 40 ° C., but as is clear from Table 1, it is sufficient if the temperature is maintained for at least 15 minutes even at room temperature (25 ° C.). It was found that oxygen could be removed.
Therefore, the present invention is extremely advantageous in that no special temperature control is required, and the enzyme reaction can be carried out at a temperature at which various germs do not easily propagate, so that no special time control is required.

Experimental Example 2 Evaluation of the Flavor of Cooked Rice 90 g of polished rice was washed with water, immersed and drained, and steamed in a steamer for 3 minutes as a pretreatment to obtain 120 g of steamed rice. Next, 0.12 g of glucose oxidase and 0.24 g of glucose are dissolved in 80 g of water, and immediately mixed with the steamed rice in a tray container (material PP, size 100 × 100 × 30 mm), and a lid material (material PET / NY / PP)
Then, the mixture was kept at room temperature (25 ° C.) for 15 minutes to perform an enzymatic reaction treatment, and then subjected to a retort treatment at 122 ° C. for 25 minutes to simultaneously perform sterilization and rice cooking.

As Comparative Example 1, the treatment was performed under the same conditions as in Experimental Example 2, except that neither glucose oxidase nor glucose was added. As Comparative Example 2, the treatment was performed under the same conditions as in Experimental Example 2 except that the amount of glucose oxidase added was 0.45 g. Comparative Example 3
The treatment was performed under the same conditions as in Experimental Example 2 except that the amount of glucose added was 0.85 g.

Table 2 shows the results of evaluation of the flavor of the cooked rice obtained in Experimental Example 2 and Comparative Examples 1 to 3.

[0034]

[Table 2]

As is clear from Table 2, in Experimental Example 2, no off-flavor was generated and the flavor was good, whereas in Comparative Examples 1 to 3, various off-flavors were generated, and the flavor was good. Had a problem. From these results, by coexisting glucose oxidase and glucose, it is possible to suppress the generation of off-flavor peculiar to retorted cooked rice, and furthermore, by using these in a specific amount, the generation of off-flavor and the improvement of flavor It was found that high quality retort cooked rice could be obtained.

[0036]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Example 1 900 g of polished rice was washed with water, immersed and drained, and steamed for 3 minutes with a steamer as a pretreatment to obtain 1,200 g of steamed rice.
Next, 120 g of the steamed rice was placed in a tray container (material P
P, size 100 × 100 × 30 mm). On the other hand, after dissolving 1 g of glucose oxidase and 3 g of glucose in 800 g of water, immediately dispens 80 g each into the tray container filled with the steamed rice, mix with the steamed rice, and seal with a lid material (Material PET / NY / PP). After doing
After holding at room temperature (25 ° C.) for 15 minutes for the enzyme reaction,
A retort treatment was performed at 122 ° C. for 30 minutes to cook rice at the same time as sterilization to obtain high-quality retort cooked rice having an improved flavor without generation of a peculiar odor peculiar to retort cooked rice.

Example 2 1,800 g of polished rice was washed with water, immersed and drained, and as a pretreatment, steamed rice was previously steamed for 4 minutes using a steamer to obtain 2,400 g of steamed rice. Next, after dissolving 2.8 g of glucose oxidase and 4 g of glucose in 1600 g of water, this was added to the steamed rice and mixed, and immediately and continuously, continuously in a tray container (aluminum, size 150 ×). 150 × 3
0mm) and cover material (Material PET / NY / PP)
Then, the mixture was kept at room temperature (25 ° C.) for 15 minutes to carry out an enzymatic reaction, and then subjected to a retort treatment at 122 ° C. for 25 minutes, followed by sterilization and rice cooking.

When the retort cooked rice thus produced was opened and its flavor was evaluated, the retort cooked rice did not generate any offensive odor and deterioration of flavor. It was of high quality, comparable to cooked rice.

[0039]

According to the present invention, it is possible to effectively prevent the deterioration of the flavor due to the oxidation of the components contained in the rice grains during the retort sterilization, particularly the oxidation of the fats and oils, in the usual series of simple retort cooked rice production processes. it can. Further, according to the present invention, not only oxygen dissolved in the water around the rice grains, but also oxygen contained in the water in the rice grains can be removed through the water, so that the oxygen is present around the oils and fats contained in the rice grains. Oxygen can be almost completely removed, and therefore, according to the present invention, the generation of a peculiar odor peculiar to retort cooked rice due to the oxidation of oil and fat components present in rice grains, which could not be avoided by retort sterilization, and the deterioration of flavor are reduced. It has a feature that can be almost suppressed.

Claims (2)

(57) [Claims] 1. Glucose oxidase and glucose are dissolved in a mixed system consisting of rice and an amount of water necessary for cooking rice, filled in a container, sealed and kept for a time required for the enzyme reaction. Thereafter, a method for producing retort cooked rice with improved flavor, wherein sterilization and cooking are simultaneously performed by retort treatment. 2. The amount of each of glucose oxidase and glucose added to the mixed system is 0.01 to 0.01.
The method for producing retorted cooked rice with improved flavor according to claim 1, wherein the content is 0.2% by weight and 0.01 to 0.4% by weight.