JPH05304910A - Washed and dried rice and packaging method - Google Patents

Abstract

PURPOSE:To prepare washed and dried rice having the main water-absorbing part on the surface layer of rice grain, free from crack on the surface of the grain, having an average water content lower than a prescribed level and having excellent palatability, freshness and preservability by washing polished rice in water and removing the water from the rice grain while carrying out the procedures from the immersion in water to the removal of water within a prescribed period. CONSTITUTION:The objective washed and dried rice is prepared by washing polished rice in water to effect the removal of sugar and removing the water from the rice. The water-absorbing part of the rice grain is mainly restricted in the surface layer of the grain during the above procedures and the process from the immersion in water to the removal of water is carried out within several minutes. The sugar in the recess on the rice grain can sufficiently be removed by this process and the product has an average water content not higher than 13-16%. Preferably, the washed rice is packaged with an airtight packaging material and sealed in a state almost free from unnecessary spaces between the rice and the packaging material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to dry-washed rice which can be cooked immediately by adding water and a packaging method thereof.

[0002]

2. Description of the Related Art Rice is washed many times by consumers every time they cook rice. This is cumbersome and it takes time to cook rice. In addition, from the viewpoint of preventing river pollution due to stink juice, it is desirable to wash rice before reaching consumers if possible. However, until now, dry-washed rice that has been washed and dried and that can be eaten deliciously even after boiling with water has not been produced. Problems in drying washed rice are rotting and crushed rice. That is, when the rice is washed, it absorbs water during that time and the water content becomes high, and if it is left as it is, it will rot or mold, and if it is dried to avoid it, the rice will crack first, Furthermore, since it is crushed into grains, even if it is cooked, it will become sloppy rice and will not be usable at all.
Therefore, once milled rice is soaked in water, if it is dried, cracks will always occur and it will be crushed into particles.
The previously known dry-washed rice is not delicious when cooked and eaten, and was not suitable for cooking rice. As the dry-washed rice obtained by washing with water and then drying, conventionally, for example, rice that has been milled is washed and drained and then naturally dried or heat-dried (JP-A-57-141257). , Dried by blowing cold or room temperature air
(Japanese Patent Laid-Open No. 61-11585), white rice washed with water and drained, and then adjusted to have a water content of 15% to 16% (Japanese Patent Publication No. 51-22063) are known. Further, as the rice that can be cooked without being ground (non-washed rice) as well as the dry-washed rice, one prepared by a method other than washing with water has been conventionally known. Typical examples are polished rice obtained by polishing and polishing rice with a slight amount of water added to polished rice, and unwashed rice obtained by washing and polishing the polished rice with alcohol to remove the alcohol ( JP-A-60-54650). The former is not washed by immersing rice in water, so it is invisible to the naked eye of rice skin, and there are traces of micron-sized bran powder and small cave-shaped germs that have entered the countless minute depressions. The bran powder that has entered is left without being removed. The turbidity value of the wash water of the polished rice (the turbidity value of the wash water at the time of washing the rice by the measuring method of the Japan Rice Milling Industry Association. The turbidity described in this specification is the same.) Is around 100 PPM Therefore, when cooking rice, 10 ordinary polished rice
Abrasive rice does not need to be washed because it only requires five times to wash and rinse rice once. Further, the latter had a problem that the alcohol had to be completely removed and the taste of cooked cooked rice was deteriorated. The conventional washed rice or unwashed rice that can be cooked immediately without washing at the time of rice cooking is as described above, but washing of polished rice, bran removal and water removal are performed within a short time of several minutes, and there is no crack on the rice skin Dry-washed rice and its packaging method are not known.

[0003]

[Problems to be Solved by the Invention] Raw rice, which does not need to be washed at all, not only complicates cooking, but also contributes to prevention of polluted water. Therefore, it can be cooked immediately by adding water. It has been a long time since consumers requested "dry washed rice." Although studies have been made to obtain such dry-washed rice, no cooked cooked rice with excellent taste has been produced. In view of such a point, the present invention is
The object of the present invention is to obtain dry-washed rice in which cracks do not occur in the rice grains even after washing and drying and the taste of cooked cooked rice is not deteriorated, and further to provide a packaging method thereof.

[0004]

[Means for Solving the Problems] The present invention was conducted as a result of intensive research to obtain washed rice in which cracks do not occur even after washing rice and the taste of cooked cooked rice is excellent, resulting in washing of polished rice in water, The inventors have completed the invention by discovering that if the rice bran removal step and the water removal step are performed in an order of magnitude shorter than the conventional one, dry-washed rice suitable for cooking rice can be obtained without cracks in the rice grains. In order to achieve the above object, the dry-washed rice of the present invention is washed with polished rice in water,
After removing rice bran and further removing water, the main part of water absorption of the rice grain during this time is the surface layer of the rice grain, which was obtained by dipping in water and removing water within a few minutes. No cracks were generated and the bran content in the depressions on the rice surface was sufficiently removed, and the average water content was about 13% to 16%.
In the method for packaging dry-washed rice of the present invention, the above-mentioned dry-washed rice is covered with an airtight packaging material and sealed so that there is almost no excess space between the packaging material and the dry-washed rice. If washing and water removal are performed while the water-absorbing part of the rice grains in the washing and dewatering steps is mainly the surface of the rice grains, cracks will not occur after the dewatering. The average water content (hereinafter, simply referred to as "water content") of the rice grains after water removal after maintaining such a water content is 16% or less. The time width in which the water absorbing part is the surface part of the rice grain varies depending on the washing method, washing conditions, etc., but it must be within a few minutes. Within a few minutes means a time shorter than about 3 minutes to 4 minutes, preferably 2 minutes to 3 minutes, more preferably 1 minute.
Within minutes. When water is washed into the rice grains during washing, the rice cracks when it dries and does not become delicious rice when cooked. The fact that the water content of the rice grains does not exceed 16% is also the upper limit of the water content that can prevent spoilage when the rice grains are stored at room temperature. The lower limit of water content is about 13%
The reason is that the water content of milled rice is usually about 13% or more. In the present invention, the "water content" of washed rice is the "average water content" when the attached water is removed. Since the water content is expressed as an average value, the rice grains do not always have a uniform water content. The water content is determined by using the usual method for measuring rice grains. The washing method for obtaining the dry washed rice of the present invention is not particularly limited as long as it is a method capable of efficiently removing bran in a short time. For washing the polished rice, a known continuous rice washing machine can be used, but some modification is required. That is, it is desirable to modify the rice washing tank so that it has a small diameter and a rotation speed of 600 rpm or more. Hereinafter, the method for producing dry washed rice of the present invention will be described in more detail.

When washing with a rice washing machine, the number of revolutions and the diameter of the kneading machine are determined in relation to the amount to be treated, but the point is that the milled rice supplied must have the agitation frequency necessary for sufficient rice washing in the tank. It is important that the rice washing machine is designed so that the water content after removing water, that is, when the attached water is removed, the so-called internal water content is 16% or less even after the time required for receiving is there. In the first place, after harvesting rice, except for a part of the area, it is compulsory to dry it with brown rice to a moisture content of 15% or less, and if it is more than that, inspection will not pass, so it is usually 13% to 14%. It is distributed as hydrous brown rice. In addition, even if tempering is performed, water escaping of about 0.5% to 1% is unavoidable in the polishing process, so that the final moisture content when polished rice is about 14%. So normal 14%
There is no risk of spoilage and mold formation in polished rice with a water content before and after, but when such polished rice is washed with the above-mentioned rice-washing device, if the time spent in the washing tank is long, In addition, water penetrates deeply into the rice grains, and even if the water adhering to the surface is removed, the internal water content becomes high, which causes decay and mold. Then, if the internal water content is removed by drying to prevent it, a strain will occur and cracks that are the cause of pulverization will occur, so that it is not necessary to remove the internal water content, so that the It is necessary to suppress the water content, that is, the internal water content to 16% or less. For that purpose, it is necessary to determine the number of rotations and the size of the tank in consideration of shortening the rice grain passing time in the rice washing machine in the tank. It is said that there is. In any case, it goes without saying that in order to produce the dry-washed rice of the present invention, the time required for the continuous rice-washing machine to pass through the tank must be shortened by an order of magnitude more than before. In addition, it is necessary to consider the water absorption of polished rice and the temperature of washing water when setting the in-tank time. That is, the higher the water temperature is, the faster the water absorption speed is, and therefore the tank passing time needs to be shortened. The point is that in any case of using a continuous rice washing machine, the time for which the rice is present is such that almost no water penetrates into the rice grains during washing. Next, regarding the number of rotations of the rice washing machine, if the number of times the rice grains are agitated in water is small, the necessary minimum rice washing effect cannot be obtained. In order to carry out the necessary number of stirring, it is necessary to increase the rotation speed of the stirring body of the rice washing machine. In short, when washing is performed by a continuous rice washing machine, it is necessary to set the rotation speed at which the number of agitation necessary for sufficient rice washing is performed within an order of magnitude shorter than the conventional passing time in the tank. The term "sufficiently washed rice" as used herein means that the rice does not smell like rice bran when cooked as it is, that is, to the extent that the rice is generally washed by consumers at present. Innumerable microscopic depressions that are invisible to the naked eye on the surface and micron-sized bran powder that has entered the traces of germs are almost removed, that is, when washing it again, the washing water is It refers to a state in which there is almost no cloudiness. In this way, sufficient rice washing is carried out, and it comes to be discharged from the rice washing machine, but in most rice washing machines, since rice grains are discharged together with a large amount of washing water, it is not necessary to put a hair between them. Immediately, not only the washing water but also the adhering water adhering to the surface of the rice grain is removed by the water removing device provided in the subsequent step of the rice washing device. The dewatering device may be a known device as long as it has a function of removing the washing water and the adhering water, but it does not take time to remove the washing water. This is because it is meaningless if the rice grains are prevented from absorbing water in the rice washing process, but it takes time to remove the washing water in the water removing process and the washing water is absorbed inside the rice grains. Of course, there is a known water removing device that can remove most of the washing water, which causes water absorption, in a short time close to the moment, so it should be selected. When the polished rice is passed through the washing process and the water removing process as described above, the polished rice is washed and removed in an extremely short time, so that the water does not almost penetrate into the rice grains and is removed. When discharged from the water system, the water content does not exceed about 13% to 16%,
Even if it is left in the room for a long period of time, almost no cracks occur on the surface, and of course, dry washed rice that has not been crushed is obtained. It can be easily imagined that the water content of the rice grains after removal of water is higher than that of the inside, but the average water content of one grain does not exceed 16%. That is, the high water content portion of the surface is extremely thin, and therefore even cracks do not occur. In other words, the conventional concept is that washing rice immediately absorbs water to the inside of the rice grain and makes the whole grain high in water content. To remove it, there was no choice but to dry it. .. However, in the present invention, it is only the very surface that is made water-rich even if it is washed with rice, and the water content is not made high to the inside. It is still in the state. That is, the water content does not exceed 16%. The water on the surface of the freshly removed rice grains will soon migrate to the inside and be balanced. As described above, the dry-washed rice of the present invention is produced by completely treating each process from washing to removing water in a very short time until it absorbs about 2% of water. The surface of the dry-washed rice of the present invention is more brittle than that before washing with water, and fine scratches are generated when rubbing against each other. Therefore, it is necessary to package the rice so that the rice grains do not rub against each other. Details are as follows

The operation will be described in the section.

[0006]

[Function] Generally, the first cause of cracks in rice that has been hydrated by washing water and then dried is that the rice grains, which have weak strain characteristics, partially expand and contract when absorbing water and removing water. Is caused and distortion is generated. If it is possible to suppress the amount of water absorption and the amount of water removal that does not cause expansion and contraction, which are factors of strain, during washing and water removal, then wash the polished rice even in water. ,
It will not crack even when dried. By the way, milled rice has extremely peculiar physical properties with respect to water absorption, and it is necessary to deal with it after first understanding it. That is, milled rice reaches a saturation point moisture content of about 30% in about 1 hour after being immersed in water. However, this also causes a considerable time difference depending on the water temperature and rice quality. However, in any case, the relationship between the immersion time and the increase in water content does not progress at a constant rate, but rather progresses extremely anti-acceleratingly. Therefore, immediately after the immersion, the water absorption amount in the first 1 second is so steep that the water absorption amount in the first 1 second is comparable to the water absorption amount in the last 10 minutes.
It goes without saying that the water absorption amount in the first 0.1 second is much larger than the water absorption amount in the last 0.1 second. As described above, the water absorption property of rice is such that the water absorption speed is gradually decreased with time as soon as it is immersed in water. Therefore, since it absorbs a considerable amount of water even in an extremely short time immediately after soaking, in order to prevent distortion when it is dried, wash rice is completed within a short time, Immediately remove water. On the other hand, it is necessary to consider the washing characteristics of polished rice. That is, the surface of milled rice has innumerable and minute depressions that are invisible to the naked eye, and in order to remove the starch granules and bran dust that have entered them, it is absolutely necessary to dip the rice grains into water. It is necessary to stir and wash rice at least 30 times or more. The reason for this is that the depressions in which the bran powder has entered have a greater depth than the opening surface, and most of them are narrow openings in the micron range, so it is necessary to remove the bran powder that has entered the back. Is immersed in water and stirred vigorously,
There is no choice but to wash off the bran powder by suspending it in water. However, it is necessary to carry out such washing of rice within a short time as described above. When producing the dry-washed rice of the present invention based on such a consideration, in the washing step, the polished rice is soaked in water for an extremely short time to remove the bran and immediately remove the rice. By the water process, the washing water and the water adhering to the surface will be removed. The time from immersion in water to removal of water is within a few minutes, and the water content of rice when removed is within the range of not more than about 13% to 16%. As a result, when the rice is washed, water does not penetrate into the inside of the rice grain, and crushed as well as sized dry washed rice with no cracks can be obtained. Also, it has a turbidity of not more than 76 PPM even if it is soaked in water again and washed with rice. still,
The turbidity value of 76 PPM is the lower limit of the numerical value in the measuring method of the Rice Milling Industry Association, and the turbidity value of less than this, that is, it cannot be measured when the washing water is clean. Become. However, there was no rice with a high degree of bran removal that could not be measured by this measuring method, so it could be measured sufficiently by this measuring method, but the dry washed rice of the present invention has a turbidity value. Is too low to measure with this measuring method. Therefore, in this specification, "76P.
The expression "P.M. or less" means that the turbidity is so low that it cannot be measured by the conventional measuring method, which means that it is considerably lower. Or less ”. In addition, in the present specification, it means “dry” which is expressed as dry-washed rice, but even if the rice grains are stored at room temperature, the limit is such that they do not rot or mold, that is, the water content is about 16%. It means that the water content does not exceed the limit.
Further, the meaning of "crack" of rice grain is a crack that can be clearly confirmed by the naked eye. Further, in the meaning of "polished rice", it refers to not only perfect polished rice but also excess polished rice and half-polished rice. Further, the meaning of "washed rice" or "washed with water" is to wash by stirring the rice grain group in a large amount of water that is soaked in water.

Next, the dry washed rice of the present invention is packaged in a substantially degassed state. The surface of dry-washed rice is more brittle than that before washing with water, and if the rice grains rub against each other during transportation, the surface of the rice grains becomes rough, that is, countless minute scratches occur, which causes deterioration in taste. Becomes Therefore, regarding packaging, it is necessary to prevent the rice grains from rubbing against each other. This object can be achieved by the packaging method of the present invention. That is,
Since there is almost no extra space between the encapsulated dry-washed rice and the packaging material, rice grains are suppressed from moving,
The positional relationship between the grains remains almost unchanged. Therefore, even if the packaging bag is erected or laid down when it is carried, the rice grains do not rub against each other in the bag, so that no roughness occurs. Further, even if external pressure is applied during storage or transportation, it can be prevented from being applied to the rice grains inside, so that skin roughness and crushing do not occur. Originally, rice is
Unless it can be packed in a vacuum bag or a bag filled with an inert gas, it is covered with a packing material having a ventilation hole. There are various reasons, but the first reason is to keep the quality of rice. In such a packaging form, when carrying during transportation, the packaging bag stands up or is laid down, but each time,
The apparent volume of rice grains in the bag changes. That is, when the bag is laid down sideways, the rice grain group becomes thin and the apparent volume is the smallest, and when standing up, the rice grain group moves downward and becomes thicker and the apparent volume becomes larger. The increased apparent volume is occupied by the air that has entered through the ventilation holes provided in the bag material. On the other hand, when the standing bag is laid down, the rice grains inside spread out thinly and the apparent volume becomes small, so the excess air is discharged from the ventilation holes of the packaging material. In this way, the rice grains in the packet move each time they are erected or laid down, and at that time, the rice grains slide against each other. Although it cannot be said that such rubbing is not harmful even with conventional rice, dry washed rice is bran powder that adheres to rice skin by washing rice, that is, so-called "clothes".
Since the one corresponding to the above is removed, the harmful effect of the rubbing between bare rice skins is great.However, in the packaging method of the present invention, the excess air in the packaging bag is roughly removed with the smallest apparent volume of the rice grain group. Since it is sealed air-tightly, even if the direction of the bag changes and the apparent volume increases, that amount of air does not enter from the outside, so it keeps the shape with the smallest apparent volume. The result is that rice grains do not rub each other as a result. next,
Even if external pressure is applied during storage or transportation, it is usually possible to prevent that pressure from being applied to the rice grains inside, when storing this type of rice in a packaging bag, it is laid sideways and piled up. In the packaging method of the present invention, as described above, the airtight packaging material is degassed and sealed so that there are almost no excess voids, but it is most apparent when the packaging bag is laid down sideways as described above. Since the volume is small, it can be said that the surplus space is the largest between the rice grain group and the packaging material. Therefore, even if the wrapping bags stacked on top of this wrapping bag are overloaded, the air occupying this surplus space is pressured and the rice grains are not so affected. In addition, the airtight packaging material in the present invention means not having air permeability at all, such as aluminum vapor-deposited plastic film and special plastic film, but not having air holes and the like. It also means that it is low, for example,
It also includes ordinary polyethylene film and plastic coated paper bags. In addition, the meaning of "sealed so that there are almost no excess voids" described in the present specification does not mean that the pressure is reduced to atmospheric pressure or less and put into a pressure-tightened state as in general vacuum packaging. Even though there are some gaps, it means the degree of deaeration and the degree of sealing that the rice grains do not move downward and become thicker when the sleeping bag is put up.

[0008]

Example 1 A stirrer of a rotary type continuous rice washing machine having a known structure is set at 600 rpm, and a water removing device is continuously provided at the outlet thereof to form a water washing process and a water removing process, Water of 14.2% was added to the rice washing machine by pouring water at 3 ° C.
Nagiho's milled rice from Wakayama is continuously fed at 1 kg / min. The milled rice enters Zabun into the infused water that is moving in the rice washing tank of the rice washing machine, is agitated in the water, is washed with rice, and is discharged together with the washing water from the outlet of the rice washing machine. At this point, washing water and adhering water are removed and discharged from the water removing device. In the meantime, that is, the time from when the polished rice per grain was soaked in the water of the rice washing tank to when it was discharged from the water removing device was 45 seconds (most of the time was taken in the water removing process). .. The fresh water from the water removal process has a water content of 15.9%, and even if it is left in the room for 30 days, there is no decay or mold, and 1 in 10 grains
Only the proportion of grains cracked (the original milled rice was cracked rice at a rate of 1 grain to about 50 grains), and there was no crushing (excluding the crushed grains from the beginning). It remained in the sized group. When the washed rice was rewashed, the washing water had a turbidity of 76 PPM or less, and I boiled it in water without washing it, but because it is washed well, it has more bran odor than normal rice. The rice was delicious without losing its freshness. In addition, the washed rice treated as described above is put in a polyethylene packaging bag and laid sideways, and light pressure is applied by flat plates from both upper and lower surfaces to shape it flat and to discharge most of the excess air in the bag. Then, it was sealed and lifted by hand and shaken by standing or tilting, but there was almost no movement of rice grains in the bag. Moreover, this was subjected to a weighting and delivery test, but no roughening of the rice grain occurred.

[0009]

[Example 2] The number of revolutions of the above-mentioned rice washing machine was set to 1800 revolutions per minute, and a dewatering process with a high performance dewatering device was constructed.
After injecting water at ℃, the polished rice of Nihonbare produced in Wakayama prefecture in 1960 with a water content of 13.8% is continuously introduced at a speed of 10 kg / min. In this case, the time from when the polished rice was soaked in the water in the washing tank to when it was discharged from the water removing device was about 5 seconds. The water content of the freshly discharged rice is 14.5%.
Even if it is left in the room for 30 days, there is no decay or mold, there is no single rice grain with cracks (excluding cracked rice from the beginning), and of course, crushed grain However, the original sized group remained (except for crushed particles from the beginning). When the washed rice was washed again, it had a turbidity of 76 ppm or less, and even if it was cooked in water without washing, the freshness was good and the rice was a little tastier than usual.

[0010]

[Example 3] In order to evaluate the taste of the dried washed rice of the present invention when cooked, samples 1 to 4 were subjected to a taste test on a panel of 24 people. As sample rice, Showa 63
Annually produced and polished rice from Akitakomachi was used as the same raw material. The rice cooking conditions are the same. Sample 1 (control product) is rice cooked after normal washing, and sample 2 (control product) is washed with hot alcohol, dried and cooked washed rice without alcohol. is there. Sample 3 (control product) was prepared by washing rice after being washed by a normal method, then drained and dried, and Sample 4 (invention product) was prepared by washing the rice by the method of Example 2 and removing dry washed rice. It is cooked. The evaluation method is based on Sample 1,
A method in which each paneler evaluated whether or not the taste was better than that was used. The evaluation points are as follows, but Sample 1 was evaluated as 0. ○ Same as sample 1. ………… 0 ○ Slightly tastier than 〃… +1 ○ Slightly worse than Sample 1 …… -1 ○ A little tastier than 〃 ……… +2 ○ A little worse than 〃 ………… -2 ○ Much better than 〃 Tasty …… +3 ○ Much worse than 〃 ……… -3 ○ 〃 Much tastier than ... -4 ○ 〃 Much worse than …… -4 ○ 〃 Most tastier +5 ○ 〃 Mess tasting …… -5 Taste test The results are shown in Table 1. As is clear from the above results, the dry-washed rice of the present invention (Sample 4) is a control product.
It was much more delicious than (Samples 2 and 3). In addition, the dry washed rice of the present invention has a better taste when cooked than the washed rice that has been washed and dewatered by a usual method.

[0011]

The dry washed rice of the present invention has the following effects (1) to (4). (1) The dry-washed rice of the present invention can be produced at a low cost, and when it is cooked, it can be cooked as it is without becoming cloudy even if it is put in a pot with water, which has been a long-standing desire. It is possible to save the labor of consumers to wash rice. In addition, since the rice surface has no cracks and the rice surface depressions are sufficiently removed, the cooked rice has no odor of rice bran, is shiny, and is delicious. Moreover, the product of the present invention in which almost all the bran dust is removed does not deteriorate in freshness as compared with conventional rice and has good storability. (2) The dry-washed rice of the present invention has a higher vitamin content than conventional rice. This is because the product of the present invention is washed with rice for a short time, so that water-soluble vitamins are less likely to flow out, and consumers can eat it without washing it. (3) The rice of the present invention has a good washing yield and is socially beneficial. This is because conventional rice washing is done by high pressure both manually and mechanically with high pressure, so the substance that originally wants to remain on the rice skin will be peeled off and washed away, but with the product of the present invention, the water in the rice washing tank can be stirred at high speed. Since the rice is washed, pressure is not applied to the rice grains, and as a result, there is little peeling of substances other than the residual bran that deteriorates the taste. (4) The dry-washed rice of the present invention can be cooked only by adding water, so that the river is not contaminated by the polishing liquid. Further, according to the method for packaging washed rice of the present invention, the movement of rice grains inside the package can be suppressed and the external pressure can be prevented at the same time. No rubbing and no rough rice or broken rice. For this reason, it becomes possible to safely deliver the dry-washed rice, which has difficulty in strength, by the current transportation method.

[Table 1]

Claims (2)

[Claims] 1. Polished rice is washed in water, debranched, and further dewatered. During this time, the main water-absorbing part of the rice grain is the surface layer of the rice grain, and it takes a few minutes from dipping in water to dewatering. Drying characterized by having no cracks in the rice skin, sufficient removal of bran in the depressions on the rice skin surface, and an average water content of not more than about 13% to 16%. Washed rice. 2. A package of washed rice, characterized by encapsulating the dry washed rice according to claim 1 in an airtight packaging material and sealing it so that there is almost no excess void between the packaging material and the dried washing rice. Method.