Processed rice and method for producing processed rice

Abstract

To provide a technique relating to processed rice capable of cooking a plurality of kinds of rice gruel different in the ratio of the amount of rice and the amount of water under the same heating condition.SOLUTION: The processed rice comprises a starch layer comprising beta starch and a porous sub-aleurone layer on the surface of the processed rice. The sub-aleurone layer encapsulates the starch layer. The method for producing processed rice includes a first step, a second step, a third step and a fourth step. In the first step, raw material rice is immersed in water for a first time at a first temperature lower than normal temperature and higher than 0 °C. The raw rice serves as a raw material of processed rice. In the second step, the raw rice after the first step is slowly frozen for a second time at a second temperature within a range of -1 to -5 °C. In the third step, the raw material rice after the second step is thawed at a third temperature higher than 0 °C. In the fourth step, the raw rice after the third step is dried at a fourth temperature higher than the third temperature. In the fourth step, the raw rice after the third step is dried at a fourth temperature at which gelatinization of starch does not occur in the raw rice after the third step.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to processed rice that can be used as an ingredient for making porridge. [Background technology]

[0002] Patent Document 1 discloses a method for serving food. The method involves placing food on one or more dishes placed on a tray to create a serving tray containing one serving of food. A predetermined number of serving trays are then housed in a serving unit and served to each person. The serving unit is equipped with a heating means and a control means. The heating means heats each of one or more dishes placed in a predetermined position on the tray. The control means reads cooking information for each person from a storage medium. The storage medium stores the cooking information. The cooking information is attached to each tray and includes ingredients, seasonings, and portions tailored to each person. The control means controls the heating means of each of the multiple trays at a preset heating start time, heating time, and heating temperature. The method involves placing ingredients tailored to each person, ingredients seasoned to each person, ingredients in a customized amount, or ingredients with seasonings tailored to each person, on one or more dishes for each dish to be cooked, and placing the dishes in a predetermined position on the tray to create a serving tray for each person. The serving method stores a predetermined number of these serving trays in a serving body, cools and stores the ingredients on the serving trays stored in the serving body, operates a heating means at a preset time, completes cooking of the ingredients for each dish on each person's serving tray by the time serving starts, and when the time serving starts arrives, removes the serving trays from the serving body and serves each person's serving tray to the corresponding person.

[0003] Patent Document 2 discloses a method for producing rice for instant porridge. In this production method, rice is placed in hot water at or above the gelatinization temperature to bring the moisture content to approximately 50-70%. Rice with a moisture content of approximately 50-70% is not completely gelatinized to the core of the rice, but is instead partially gelatinized rice, in which the surface layer is mainly gelatinized. The production method then involves rolling the rice and then drying it. This method produces rice for instant porridge with a degree of gelatinization of 70-95%.

[0004] Patent Document 3 discloses a method for processing rice, in which soaked rice is steamed for 5 to 20 minutes. In this method, only the surface of the rice grain is gelatinized, while the center remains in a β-starch state. The grain is then either allowed to absorb a seasoning liquid or dried at 50 to 70°C until the moisture content reaches approximately 13 to 15%.

[0005] Patent Document 4 discloses a method for producing quick-cooking rice. In this method, brown rice and polished rice (hereinafter referred to as polished rice, etc.) are soaked in water or warm water to adjust the moisture content to 20-30%. The rice is then rapidly frozen and then dried under reduced pressure. Quick-cooking rice has good water permeability because the structure of polished rice, etc., becomes porous due to freeze-drying under reduced pressure, and heat is also easily conducted to the inside of the endosperm. Quick-cooking rice can shorten the cooking time.

[0006] Patent Document 5 discloses a method for producing processed rice. The production method includes the steps of obtaining heat-treated rice, rapidly cooling the heat-treated rice, obtaining swollen rice, and freeze-drying the swollen rice. In the step of obtaining the heat-treated rice, raw material rice selected from no-wash rice and polished rice is soaked directly in hot water for 1 to 5 minutes. In the step of obtaining the swollen rice, the cooled heat-treated rice is allowed to absorb water at a temperature below 65°C. The processed rice has pores. The processed rice has a gelatinized layer on the surface and an ungelatinized portion at least in the center. The processed rice has a bulk density 1.8 to 2.4 times that of the raw material rice.

[0007] Patent Document 6 discloses a method for producing freeze-dried rice. The production method comprises a soaking process, a dehydration process, a quick-freezing process, a heating process, a cooling process, and a freeze-drying process. In the soaking process, washed raw rice is soaked in water at 15 to 25°C for approximately two hours or less. In the dehydration process, the soaked raw rice is dehydrated. In the quick-freezing process, the dehydrated raw rice is quick-frozen at a subzero temperature. In the heating process, the frozen raw rice is heated at a high temperature of 95°C or higher for approximately six minutes or less. In the cooling process, the heat-treated raw rice is cooled using a cooling means. In the freeze-drying process, the raw rice cooled in the cooling process is freeze-dried. According to this production method, the following two points are achieved: low-viscosity rice grains that do not become sticky or clumpy when rehydrated in hot water or in a microwave oven are produced, resulting in firm cooked rice; and the rehydration time can also be shortened. In the first point, the soaked rice is quick-frozen at a subzero temperature to form many pores in the rice grains that allow water to penetrate. The second point is to improve heat conduction efficiency, shorten the heating time for gelatinizing the rice, and reduce damage caused by heat. By subjecting the raw rice to a quick freezing process at temperatures below -18°C for 3 to 5 hours, the pores formed in the rice can be made into precise pores.

[0008] Patent Document 7 discloses a method for producing processed rice. The production method involves a first step, a second step, a third step, and a fourth step. In the first step, raw material rice is washed in running water at room temperature for 1 to 5 minutes. In the second step, the raw material rice is soaked in water at room temperature for 20 to 50 minutes. In the third step, the raw material rice after soaking in water in the second step is heated in hot water or steam at 70 to 85°C or higher for 1 to 3 minutes. In the third step, the raw material rice is allowed to sufficiently absorb water. This heating increases the moisture content, progresses gelatinization to a certain extent, and makes sterilization possible. In the fourth step, the raw material rice heated in the third step is immediately cooled with cold air for 3 to 10 minutes after heating. In the fourth step, the processed rice is returned to room temperature and the moisture content and gelatinization rate are adjusted. After cooling, the processed rice has a moisture content of 35% by weight or more, preferably 35 to 40% by weight, and a gelatinization rate of 90% or less, preferably 84 to 87%.

[0009] Patent Document 8 discloses a method for producing rice and malt porridge. In addition, Non-Patent Document 1 discloses the current state and issues of rice cooking in school lunch facilities, Non-Patent Document 2 discloses processed cooked rice and its production technology, Non-Patent Document 3 discloses improving the taste and taste preservation of processed cooked rice by adjusting the rice soaking temperature and soaking time, Non-Patent Document 4 discloses the chemical structure and quality of rice cell walls, and Non-Patent Document 5 discloses the moisture content and absorption rate of polished rice. Non-Patent Document 6 discloses research on soaking in rice cooking. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 5992669 [Patent Document 2] Japanese Patent Application Publication No. 63-258545 [Patent Document 3] Special Publication No. 42-27281 [Patent Document 4] Special Publication No. 60-10695 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-66418 [Patent Document 6] Japanese Patent Application Publication No. 2019-129794 [Patent Document 7] Japanese Patent Publication No. 2022-117531 [Patent Document 8] Patent No. 6005822 [Non-patent literature]

[0011] [Non-Patent Document 1] Saeko Morii, Kaoru Sakamoto, “The current situation and issues of rice cooking in school cafeterias”, [online], [Retrieved May 17, 2024], Internet<URL:https: / / www.jstage.jst.go.jp / article / jhej / 71 / 2 / 71_93 / _pdf / -char / ja> [Non-patent document 2] Mitsuyuki Tabuchi, "Processed rice products and their manufacturing technology", [online], [Retrieved May 17, 2024], Internet<URL:https: / / www.jstage.jst.go.jp / article / jag1972 / 40 / 2 / 40_2_169 / _pdf> [Non-patent document 3] NARO, "Improvement of the Taste and Taste Preservation of Processed Cooked Rice by Adjusting the Rice Soaking Temperature and Time," [online], [Retrieved May 2, 2024], Internet<URL:https: / / www.naro.go.jp / project / results / laboratory / nfri / 1994 / nfri94-07.html> [Non-patent document 4] Naoto Shibuya, “Chemical Structure and Quality of Rice Cell Walls”, [online], [Retrieved May 17, 2024], Internet<URL:https: / / www.jstage.jst.go.jp / article / nskkk1962 / 37 / 9 / 37_9_740 / _pdf / -char / ja> [Non-Patent Document 5] Kikuo Noshiro, "Moisture content and absorption rate of white rice", [online], [Retrieved May 17, 2024], Internet <URL:https: / / www.jstage.jst.go.jp / article / jbrewsocjapan1915 / 71 / 10 / 71_10_744 / _pdf / -char / ja> [Non-patent document 6] Saeko Morii, "Research on soaking in rice cooking", [online], [Retrieved June 26, 2024], Internet<URL:https: / / www.jstage.jst.go.jp / article / cookeryscience / 54 / 2 / 54_85 / _pdf> Summary of the Invention [Problem to be solved by the invention]

[0012] In Japan, rice is a staple food and is used to make cooked rice and porridge. Rice is rich in nutrients. Rice is polished, removing the tissues that correspond to the rice bran from brown rice. Today, polished rice is polished to a yield of approximately 90%, and this polished rice is consumed as cooked rice and porridge. Because the starch layer of polished rice is enclosed within the hard subaleurone layer, it takes a long time for it to absorb water during cooking, which is a challenge. However, the chewy texture of cooked rice is achieved by the starch layer being enclosed within the subaleurone layer, so the presence of the subaleurone layer is essential. In contrast, the starch in the starch layer needs to be dissolved out of the subaleurone layer to make porridge, so the presence of the subaleurone layer interferes with cooking. Therefore, in the current cooking method of rice porridge, rice is cooked until it breaks down in order to dissolve the starch in the starch layer. To facilitate this breaking down, physical manipulations such as the use of tools are also performed. An example of such a tool is a rice scoop.

[0013] Porridge is classified into the following types depending on the amount of water. Examples of these types are full porridge, 70% porridge, 50% porridge, and 30% porridge. For full porridge, 70% porridge, 50% porridge, and 30% porridge, the amount of rice and water is adjusted to the following ratios: That is, the ratio of rice and water is adjusted to approximately "rice:water = 1:5" for full porridge, approximately "rice:water = 1:7" for 70% porridge, approximately "rice:water = 1:10" for 50% porridge, and approximately "rice:water = 1:20" for 30% porridge.

[0014] In porridge, the higher the ratio of water to rice, the more the presence of the subaleurone layer prevents the rice from breaking down during cooking, hindering the progression of gelatinization. The inventors considered that such an event could potentially lead to aspiration accidents. The inventors devised the following method as a countermeasure against aspiration accidents. In this method, cooked porridge is placed in a second cooking device to grind the rice grains. An example of such a cooking device is a blender. For example, a blender called "robot coupe BLIXER" manufactured by F.M.I. Co., Ltd. may be used as this cooking device. However, the inventors considered that if the porridge is ground using a cooking device such as a blender after cooking, it may be necessary to consider countermeasures from a different perspective. Examples of such perspectives include an increase in the amount of work required to cook the porridge, a decrease in the porridge temperature, and the risk of food poisoning and / or infectious diseases due to secondary contamination.

[0015] The present invention aims to provide a technology related to processed rice that can cook multiple types of porridge with different ratios of rice and water under the same heating conditions until the rice has gelatinized to the point where it loses its granular shape. [Means for solving the problem]

[0016] One aspect of the present invention is processed rice comprising a starch layer containing β-starch and a porous subaleurone layer on the surface of the processed rice, the subaleurone layer containing the starch layer.

[0017] This processed rice may have a moisture content of 15% by mass or less.

[0018] The above-mentioned processed rice allows the starch in the starch layer to be easily dissolved to the outside when porridge made from the processed rice is cooked. Because the surface of processed rice is formed by a sub-aleurone layer, even if the sub-aleurone layer is porous, the processed rice has a granular shape before cooking, similar to known polished rice. The processed rice slowly loses its granular shape when heated during cooking. In porridge made from processed rice, the loss of the granular shape when heated during cooking prevents the separation of starch and water even after the porridge cools down after cooking. The processed rice can be made from any variety of raw rice. The raw rice can be either new rice or old rice. Using old rice as the raw rice helps to make effective use of old rice.

[0019] Another aspect of the present invention is a method for producing processed rice, which is specified as one aspect of the present invention, comprising: a first step of soaking raw material rice, which is the raw material for the processed rice, in water for a first hour at a first temperature that is lower than room temperature and higher than 0°C; a second step of slowly freezing the raw material rice after the first step for a second hour at a second temperature that is within the range of -1 to -5°C; a third step of thawing the raw material rice after the second step at a third temperature that is higher than 0°C; and a fourth step of drying the raw material rice after the third step at a fourth temperature that is higher than the third temperature, wherein the fourth step dries the raw material rice after the third step at the fourth temperature at which starch gelatinization does not occur in the raw material rice after the third step.

[0020] The fourth step may involve drying the raw material rice after the third step at the fourth temperature to produce the processed rice having a moisture content of 15% by mass or less.

[0021] The second step may involve slowly freezing the raw material rice after the first step for the second period in the state after the first step is completed.

[0022] According to the above-mentioned method for producing processed rice, it is possible to produce processed rice that contains β-starch in the starch layer and has a porous subaleurone layer that forms the surface. The raw material rice needs to be heated in order to convert β-starch to α-starch. In the method for producing processed rice, starch in the raw material rice is not gelatinized, and there is no need to convert β-starch to α-starch. The energy required to carry out the method for producing processed rice can be reduced, thereby realizing energy savings. By not converting β-starch to α-starch, a taste similar to that of known polished rice can be obtained. [Effects of the Invention]

[0023] According to the present invention, by using processed rice as the ingredient, it is possible to cook multiple types of porridge with different ratios of rice and water under the same heating conditions until the porridge has gelatinized to the point where it loses its granular shape. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a cross-sectional view showing the general structure of the cellular tissue of brown rice and raw material rice. The upper part shows brown rice, and the lower part shows raw material rice. [Figure 2] These are electron microscope photographs of the surface of processed rice, showing the subaleurone layer of processed rice. The top row is magnified 30x. The bottom row is magnified 500x. [Figure 3] These are electron microscope photographs of a cross section of processed rice, showing the starch layer of the processed rice. The top photo is at 300x magnification, and the bottom photo is at 500x magnification. [Figure 4] These are electron microscope photographs of raw rice, showing the subaleurone layer of raw rice. The top row is at 30x magnification. The bottom row is at 500x magnification. [Figure 5] 1 is a flowchart showing the steps of a method for producing processed rice. [Figure 6] This is a table showing the analytical test results of the nutritional components of raw rice and processed rice. [Figure 7] These are photographs showing cooked rice, full porridge, 70% porridge, 50% porridge, and 30% porridge cooked using the first cooking method of an embodiment that employs the technology disclosed in Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0025] Embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the configurations described below, and various configurations can be adopted within the same technical concept. For example, some of the configurations described below may be omitted or replaced with other configurations. The present invention may also include other configurations.

[0026] <Processed rice 10> Processed rice 10 will be described with reference to Figures 1 to 4. Processed rice 10 is an ingredient for making porridge. In other words, porridge is obtained by cooking processed rice 10. Processed rice 10 may be made from non-glutinous rice or glutinous rice. In the embodiment, the rice that is the raw material for processed rice 10 is referred to as "raw material rice 20," and the method for producing processed rice 10 from raw material rice 20 is referred to as "method for producing processed rice 10." The method for producing processed rice 10 will be described later.

[0027] The raw material rice 20 is obtained by polishing non-glutinous or glutinous brown rice 30 (see Figure 1). The brown rice 30 includes multiple coating layers (see the upper part of Figure 1). Examples of multiple coating layers include the epidermis 40, pericarp 41, seed coat 42, aleurone layer 43, sub-aleurone layer 50, and starch layer 51. The epidermis 40, pericarp 41, seed coat 42, aleurone layer 43, sub-aleurone layer 50, and starch layer 51 are stacked in this order from the surface side to the inside of the brown rice 30. The starch layer 51 contains β-starch. The processed rice 10 uses polished rice obtained by polishing brown rice 30 as the raw material rice 20. Polishing involves peeling the epidermis 40, pericarp 41, seed coat 42, and aleurone layer 43 from the brown rice 30 (see Figure 1). The epidermis 40, pericarp 41, seed coat 42 and aleurone layer 43 peeled from brown rice 30 are called "rice bran" or simply "bran."

[0028] The processed rice 10 uses polished rice, which is obtained by polishing brown rice 30 to a yield of approximately 90%, as the raw material rice 20. However, a polishing yield of 90% is merely an example. The polishing yield is determined appropriately taking into account various conditions. The inventors have recognized that the following phenomenon occurs when polished rice polished to a yield of approximately 70% is used as the raw material rice 20. In this phenomenon, the polished rice does not lose its granular shape when immersed in water, but loses its granular shape during subsequent processing. This is because polishing to a yield of approximately 70% causes all of the subaleurone layer 50 to peel off. In this regard, the inventors believe that polished rice polished to a yield of approximately 70% is not suitable as a material for the processed rice 10.

[0029] The processed rice 10 includes a starch layer 51 and a sub-aleurone layer 50 (see Figures 2 and 3). The β-starch in the starch layer 51 changes to α-starch when heated. The change from β-starch to α-starch that occurs with heating is called "gelatinization" or "gelatinization." In the embodiment, this change is called "gelatinization." The α-starch changes to β-starch as the temperature decreases over time. The change from α-starch to β-starch that occurs with a decrease in temperature is called "retrogradation." The sub-aleurone layer 50 forms the surface of the processed rice 10 (see Figure 2). The sub-aleurone layer 50 contains the starch layer 51 (see Figure 3).

[0030] The sub-aleurone layer 50 remains on the raw material rice 20 after polishing (see the lower part of Figure 1). In other words, the sub-aleurone layer 50 forms the surface of the unprocessed raw material rice 20. "Unprocessed" refers to the state before the first step of the method for producing processed rice 10, which will be described later. In processed rice 10, the sub-aleurone layer 50 is porous (see Figure 2). In raw material rice 20, the sub-aleurone layer 50 on the surface is not porous (see Figure 4). The method for producing processed rice 10 makes the sub-aleurone layer 50 on the surface of raw material rice 20 porous. In processed rice 10, the moisture content is set to 15% by mass or less. However, the moisture content of processed rice 10 is preferably 13 to 14% by mass or 12% by mass or less.

[0031] <10 ways to make processed rice> A method for producing processed rice 10 will be described with reference to Figure 5. The method for producing processed rice 10 includes a first step, a second step, a third step, and a fourth step. In this embodiment, the method for producing processed rice 10 further includes a fifth step. The first step, the second step, the third step, the fourth step, and the fifth step are carried out in this order. Processed rice 10 produced by this method does not require washing or soaking in water before cooking.

[0032] In the first step, the raw material rice 20 is soaked in water at a first temperature for a first hour. The first temperature is set lower than room temperature and higher than 0°C. An example of "under the first temperature" is an atmosphere set at 5°C. A known device with a refrigeration function can be used in the first step. In this case, "under the first temperature" can be achieved by setting the storage chamber of this device to the first temperature. An example of the first hour is 12 hours. However, the first hour may be set longer than 12 hours. The first hour is determined appropriately taking various conditions into consideration. In the first step, the raw material rice 20 is placed in a water-resistant first container for soaking, and water is placed in this first container. The raw material rice 20 is soaked in water in the first container. An example of the first container is a water-resistant container. The raw material rice 20 absorbs water. The amount of water is at least equal to the mass of the raw material rice 20 placed in the container.

[0033] In the second step, the raw material rice 20 after the first step is slowly frozen for a second period at a second temperature. The second temperature is within the range of -1 to -5°C. An example of the "second temperature" is an atmosphere set to a predetermined value in the range of -1 to -5°C. A known device with a slow freezing function can be used in the second step. This device may be the same as the device used to achieve the "first environment" in the first step, or it may be different from the device used to achieve the "first environment" in the first step. When the first and second steps are performed using the same device, the "first environment" and the "second environment" may be achieved in a single storage chamber, or may be achieved in different storage chambers. An example of the second period is 12 hours. However, the second period may be set to be longer than 12 hours. The second period may be set to be the same as the first period in the first step. The second period is determined appropriately taking into account various conditions.

[0034] In the second step, the raw material rice 20 after the first step is slowly frozen for a second period in the state it was in after the first step. After the first step, the raw material rice 20 is contained in the first container as is. In the first step, the raw material rice 20 and water are placed in the first container, and the raw material rice 20 is immersed in water in the first container. In the second step, the raw material rice 20 is slowly frozen in the first container at a second temperature for a second period. In the method for producing processed rice 10, at the start of the second step, no new water is supplied to the first container, and the water remaining in the first container is not removed. However, in the method for producing processed rice 10, new water may be supplied to the first container at the start of the second step. In the method for producing processed rice 10, it is not preferable to remove some or all of the water remaining in the first container at the start of the second step. Such an operation can cause the raw material rice 20 to suffer from freezer burn and discoloration in the second step.

[0035] In the second step, the raw material rice 20 is slowly frozen at a second temperature, causing the volume of water absorbed into the raw material rice 20 to expand by 1.09 times. In the second step, this volume expansion of the water absorbed into the raw material rice 20 uniformly creates micropores in the hard sub-aleurone layer 50 on the surface of the raw material rice 20. In other words, the second step makes the sub-aleurone layer 50 on the surface of the raw material rice 20 porous.

[0036] In the third step, the raw material rice 20 after the second step is thawed at a third temperature. The third temperature is set higher than 0°C. An example of "below the third temperature" is an atmosphere higher than 0°C. However, from knowledge gained in the development process of processed rice 10 and a manufacturing method for processed rice 10, the inventors know that the preferable temperature range for "below the third temperature" is 5 to 10°C. In the third step, natural thawing at the third temperature is used as the thawing method. However, in the third step, immersion thawing may also be used if clean water with a temperature range of 5 to 10°C is available. After the second step is completed, the raw material rice 20 after the second step is transferred from the first container to a second container. An example of the second container is a drying container with a mesh design. In the third step, the raw material rice 20 is thawed while transferred to the second container.

[0037] In the third step, a known device with a refrigeration function can be used. This device may be the same as the device used to achieve the "first environment" in the first step, or it may be different from the device used to achieve the "first environment" in the first step. If the device used in the first and third steps is the same, the "first environment" and the "third environment" may be achieved in a single storage chamber, or may be achieved in different storage chambers. For example, when the third step is carried out, the raw material rice 20 after the second step is naturally thawed in the second container in a storage chamber set to 10°C in a device with a refrigeration function.

[0038] In the fourth step, the raw material rice 20 after the third step is dried at a fourth temperature. The fourth temperature is set higher than the third temperature. Furthermore, the fourth temperature is set at a temperature at which starch gelatinization does not occur in the raw material rice 20 after the third step. Examples of the "fourth temperature" include the following atmospheres. This atmosphere is preferably set to a predetermined value in the range of 30 to 40°C, and more preferably set to 30°C. This atmosphere may be an atmosphere into which hot air set to a predetermined value in the range of 30 to 40°C or hot air set to 30°C is blown. In this case, this hot air may be blown onto the raw material rice 20 after the third step placed in the second container.

[0039] In the fourth step, the raw material rice 20 after the third step is dried in the state it was in after the third step. After the third step, the raw material rice 20 after the third step is contained in the second container as is. In the fourth step, the raw material rice 20 is dried in the second container at a fourth temperature. In the fourth step, a known device with a drying function can be used. This device includes a drying chamber. The drying chamber houses the second container containing the raw material rice 20 after the third step. In this case, the raw material rice 20 after the third step is housed in the drying chamber in the state it was in the second container after the third step. The drying function may be achieved by blowing hot air. In this case, the hot air may be directed toward the raw material rice 20 after the third step.

[0040] In the fourth step, the raw material rice 20 after the third step is preferably dried to a moisture content of 15% by mass or less, and more preferably dried to a moisture content of 13 to 14% by mass or 12% or less. The raw material rice 20 after the third step goes through the fourth step to become processed rice 10.

[0041] The nutritional composition of raw rice 20 and processed rice 10 is shown in Figure 6. Raw rice 20 was polished Koshihikari, a non-glutinous rice variety. The analysis was performed by the Japan Food Research Laboratories. There was almost no loss of nutritional content in processed rice 10 compared to raw rice 20. The inventors believe that natural thawing in the third step minimizes the loss of nutritional content. However, the amount of protein per 100g of processed rice 10 is lower than that of raw rice 20. In this analysis, the protein content of raw rice 20 was 5.4g / 100g, and the protein content of processed rice 10 was 5.2g / 100g, resulting in a 3.7% loss in protein content. The inventors believe that this phenomenon is due to the porous nature of the subaleurone layer 50, which is primarily composed of protein, in processed rice 10. The inventors believe that the amount of protein per 100 g of processed rice 10 is preferably a predetermined value in the range of 4.0 to 6.0 g / 100 g, more preferably a predetermined value in the range of 4.5 to 5.5 g / 100 g, and even more preferably a predetermined value in the range of 5.0 to 5.3 g / 100 g.

[0042] The fifth step is carried out after the fourth step. In the fifth step, the processed rice 10 produced through the fourth step is packaged in bags. In the fifth step, the processed rice 10 may be packaged in single servings. Examples of the mass of a single serving of processed rice 10 include 40 g (for full porridge), 30 g (for 70% porridge), 20 g (for 50% porridge), and 10 g (for 30% porridge).

[0043] <Example> The inventor conducted an experiment to confirm the effectiveness of the processed rice 10 of the embodiment. Through this experiment, the inventor confirmed that cooked rice and several types of porridge with different ratios of rice and water can be cooked under the same heating conditions. Furthermore, the inventor confirmed that several types of porridge with different ratios of rice and water can be cooked under the same heating conditions until the rice becomes gelatinized and loses its granular shape. The results obtained from this experiment are described below.

[0044] <Experimental Method> In the experiment, the first, second, third, and fourth cooking methods were used. In the first cooking method, cooked rice and several types of porridge were cooked simultaneously under the same heating conditions. In the second cooking method, cooked rice and several types of porridge were cooked under the same heating conditions. In the third cooking method, several types of porridge were cooked simultaneously under the same heating conditions. In the fourth cooking method, several types of porridge were cooked under the same heating conditions. Cooked rice was cooked using polished rice, and porridge was cooked using processed rice 10. The several types of porridge were full porridge, 70% porridge, 50% porridge, and 30% porridge. The difference between the first, second, third, and fourth cooking methods is the heat source.

[0045] In the first cooking method, an induction food cart was used to cook rice from polished rice and porridge from processed rice 10. The IH food cart used in the first cooking method employs the technology disclosed in the aforementioned Patent Document 1, which was invented by the inventor himself. Five sets of dishes and trays were prepared for the first cooking method. The five dishes were identical, and the five trays were identical. In the first cooking method, a serving of polished rice and water, with the combination of rice and water amounts shown in Table 1, was placed in the first dish, and the first dish was placed in a designated position on the first tray. The polished rice was washed in advance, and after washing, it was soaked in a specified amount of water for 360 minutes. In the first cooking method, a serving of processed rice 10 and water, with the combination of rice and water amounts shown in Table 1, were placed in the second to fifth dishes, respectively, and the second to fifth dishes were placed in their designated positions on the second to fifth trays, respectively. Then, in the first cooking method, the first to fifth trays were placed in a food serving cart, and one set of polished rice and water and four sets of processed rice 10 and water were simultaneously heated under predetermined heating conditions. In this way, in the first cooking method, cooked rice, whole rice porridge, 70% rice porridge, 50% rice porridge, and 30% rice porridge were obtained.

[0046] In the second cooking method, cooked rice was made from polished rice and porridge was made from processed rice 10 using a single-serving kamado (cooked rice) and solid fuel. The solid fuel used was a 20g type of commercially available alcohol, such as ethanol, solidified with calcium acetate. In the second cooking method, cooked rice, full-grain porridge, 70%-grain porridge, 50%-grain porridge, and 30%-grain porridge were cooked separately. For the second cooking method, a single-serving kamado (cooked rice) and water were placed in a single-serving kamado (cooked rice and water) using the rice and water amounts shown in Table 2, and the polished rice and water were heated by burning solid fuel. The polished rice was pre-washed and then soaked in the specified amount of water for 360 minutes. For the second cooking method, a single-serving kamado (cooked rice and water) using the rice and water amounts shown in Table 2 was placed in a single-serving kamado (cooked rice and water) using the solid fuel. Four sets of processed rice 10 and water were heated by burning solid fuel. In the second cooking method, cooked rice, full porridge, 70% porridge, 50% porridge and 30% porridge were obtained in this manner.

[0047] In the third cooking method, porridge was made from processed rice 10 using a microwave oven. Four dishes were prepared for the third cooking method. All four dishes were identical. In the third cooking method, one serving of processed rice 10 and water were placed in each of the first to fourth dishes, using the combinations of rice and water amounts shown in Table 3. The first to fourth dishes were covered with wet kitchen paper as a lid in the following manner. In this state, gaps were left on both sides of the kitchen paper. These gaps allowed steam generated during heating to escape. Then, in the third cooking method, the first to fourth dishes were placed in the microwave oven, and four sets of processed rice 10 and water were heated. The microwave oven was set to an output of 500W. In this way, full porridge, seven-tenths porridge, five-tenths porridge, and three-tenths porridge were obtained using the third cooking method.

[0048] In the fourth cooking method, porridge was made from processed rice 10 using a home rice cooker. The home rice cooker has a rice cooking mode and a porridge mode. In the fourth cooking method, the home rice cooker was set to the rice cooking mode. The rice cooking mode is set when cooking rice using polished rice as the ingredient. The porridge mode is set when cooking porridge using polished rice as the ingredient. In the fourth cooking method, multiple servings of processed rice 10 and water were placed in the inner pot of the rice cooker using the combinations of rice and water amounts shown in Table 4, and four sets of processed rice 10 and water were heated. Considering the volume of the inner pot of the rice cooker, the inventors determined that the preferred amount of processed rice 10 and water per cooking run would be enough for three to four people. In the fourth cooking method, multiple types of porridge were cooked using the same rice cooking mode. In this way, full porridge, seven-tenths porridge, five-tenths porridge, and three-tenths porridge were obtained using the fourth cooking method. [Table 1] [Table 2] [Table 3] [Table 4]

[0049] <Experimental Results> (1) First cooking method Using the first cooking method, full porridge, seven-minute porridge, five-minute porridge, and three-minute porridge, which do not require chewing, could be obtained under the same heating conditions as for cooked rice made from polished rice (see Figure 7). The cooked rice, full porridge, seven-minute porridge, five-minute porridge, and three-minute porridge obtained using the first cooking method had different cooked volumes due to the amount of water evaporated. However, the cooked rice, full porridge, seven-minute porridge, five-minute porridge, and three-minute porridge all had comparable textures and flavors. The full porridge, seven-minute porridge, five-minute porridge, and three-minute porridge all gelatinized to the point of losing their granular shape.

[0050] (2)Second cooking method The second cooking method produced rice porridge (whole, seven-minute, five-minute, and three-minute), which does not require chewing, under the same heating conditions as rice made from polished rice. The cooked rice, whole, seven-minute, five-minute, and three-minute porridges produced by the second cooking method differed in cooked volume due to the amount of water evaporated. However, the cooked rice, whole, seven-minute, five-minute, and three-minute porridges all had comparable textures and flavors. The whole, seven-minute, five-minute, and three-minute porridges all gelatinized to the point of losing their granular shape.

[0051] (3) Third cooking method The third cooking method produced full, seven-minute, five-minute, and three-minute porridges that did not require chewing. The full, seven-minute, five-minute, and three-minute porridges produced by the third cooking method varied in cooked volume due to the amount of water evaporated. However, all of the full, seven-minute, five-minute, and three-minute porridges had comparable textures and flavors. All of the full, seven-minute, five-minute, and three-minute porridges had gelatinized to the point where they lost their granular shape.

[0052] (4) Fourth cooking method The fourth cooking method produced full, seven-minute, five-minute, and three-minute porridges that did not require chewing. The full, seven-minute, five-minute, and three-minute porridges produced by the fourth cooking method varied in cooked volume due to the amount of water evaporated. However, all of the full, seven-minute, five-minute, and three-minute porridges had comparable textures and flavors. The full, seven-minute, five-minute, and three-minute porridges all gelatinized to the point of losing their granular shape.

[0053] <Effects of the embodiment> According to the embodiment, the following effects can be obtained.

[0054] (1) The processed rice 10 includes a starch layer 51 and a sub-aleurone layer 50. The starch layer 51 includes β-starch. The sub-aleurone layer 50 forms the surface of the processed rice 10 and is porous (see FIG. 2). The sub-aleurone layer 50 contains the starch layer 51. The moisture content of the processed rice 10 is 15% by mass or less.

[0055] Processed rice 10 allows the starch in the starch layer 51 to easily dissolve to the outside when porridge made with processed rice 10 is cooked. Because the surface of processed rice 10 is formed with the sub-aleurone layer 50, even if the sub-aleurone layer 50 is porous, processed rice 10 has a granular shape similar to known polished rice before cooking. Processed rice 10 slowly loses its granular shape when heated during cooking. In porridge made with processed rice 10, the granular shape is lost when heated during cooking, which prevents separation of starch and water even when the porridge cools after cooking. Processed rice 10 allows multiple types of porridge with different ratios of rice and water to be cooked under the same heating conditions. Porridge made with processed rice 10 gelatinizes before losing its granular shape and has the same taste as known porridge made with polished rice.

[0056] The processed rice 10 does not depend on the variety of raw material rice 20. The raw material rice 20 may be either new rice or old rice. The inventors have confirmed that there is no difference in the taste of the processed rice 10 whether one-year-old rice or old rice several years ago is used as the raw material rice 20. By using the aforementioned old rice as the raw material rice 20, the processed rice 10 is useful for making effective use of surplus rice.

[0057] (2) The method for producing processed rice 10 includes a first step, a second step, a third step, and a fourth step (see FIG. 5). In the first step, raw material rice 20 is soaked in water at a first temperature for a first hour. The first temperature is set lower than room temperature and higher than 0°C. An example of the first hour is 12 hours. In the second step, the raw material rice 20 after the first step is slowly frozen at a second temperature for a second hour. The second temperature is within the range of -1 to -5°C. An example of the second hour is 12 hours. In the third step, the raw material rice 20 after the second step is thawed at a third temperature. The third temperature is set higher than 0°C. In the fourth step, the raw material rice 20 after the third step is dried at a fourth temperature. The fourth temperature is set higher than the third temperature. At the fourth temperature, starch gelatinization does not occur in the raw material rice 20 after the third step. In the fourth step, the raw material rice 20 after the third step is dried at the fourth temperature to produce processed rice 10 with a moisture content of 15% by mass or less. In the second step, the raw material rice 20 after the first step is slowly frozen for a second period in the state after the first step is completed.

[0058] According to the manufacturing method for processed rice 10, it is possible to manufacture processed rice 10 that contains β-starch in the starch layer 51 and has a porous sub-aleurone layer 50 that forms the surface. In order to convert β-starch to α-starch, it is necessary to heat the raw material rice 20. In the manufacturing method for processed rice 10, starch gelatinization does not occur in the raw material rice 20, and there is no need to convert β-starch to α-starch. The energy required to carry out the manufacturing method for processed rice 10 can be reduced. Energy savings can be achieved by manufacturing processed rice 10 that can obtain the same taste as known porridge made from polished rice.

[0059] The inventors consider the principle behind the method for making the sub-aleurone layer 50 porous by the manufacturing method for processed rice 10 as follows: Specifically, the inventors believe that damage occurs when the moisture inside the cells of the sub-aleurone layer 50 adheres to the ice frozen outside the cells by slowly freezing the raw material rice 20 after the first step in the second step. Furthermore, the inventors believe that this damage can be ensured by the moisture inside the cells of the starch layer 51 subsequently moving into the cells of the sub-aleurone layer 50, freezing and expanding in volume. [Industrial Applicability]

[0060] The processed rice produced by the method for producing processed rice of the present invention can be used as an ingredient in cooking porridge using the technology disclosed by the inventor of the present invention in Patent Document 1. The processed rice and method for producing processed rice of the present invention are useful in popularizing the technology disclosed in Patent Document 1. [Explanation of symbols]

[0061] 10 processed rice, 20 raw rice, 30 brown rice, 40 skin, 41 pericarp 42 seed coat, 43 aleurone layer, 50 aleurone layer, 51 starch layer

Claims

1. Processed rice, a starch layer containing β-starch; A porous subaleurone layer on the surface of the processed rice; The processed rice, wherein the subaleurone layer contains the starch layer.

2. 2. The processed rice according to claim 1, having a moisture content of 15% by mass or less.

3. The method for producing processed rice according to claim 1, a first step of soaking raw material rice, which is a raw material for the processed rice, in water for a first hour at a first temperature that is lower than room temperature and higher than 0°C; a second step of slowly freezing the raw material rice after the first step at a second temperature within the range of −1 to −5° C. for a second period of time; a third step of thawing the raw material rice after the second step at a third temperature higher than 0°C; a fourth step of drying the raw material rice after the third step at a fourth temperature higher than the third temperature, A method for producing processed rice, wherein the fourth step is drying the raw material rice after the third step at the fourth temperature at which starch gelatinization does not occur in the raw material rice after the third step.

4. 4. The method for producing processed rice according to claim 3, wherein the fourth step comprises drying the raw material rice after the third step at the fourth temperature to produce the processed rice having a moisture content of 15% by mass or less.

5. 5. The method for producing processed rice according to claim 3, wherein the second step involves slowly freezing the raw material rice after the first step in the state after the first step is completed for the second period.

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