Manufacturing method of frozen cooked rice food

Abstract

Disclosed is a method for manufacturing a frozen cooked rice food product. This method includes: a step (A) for obtaining cooked rice by boiling raw rice; a step (B) for cooling the surface of the cooked rice boiled in step (A) to within the range of -1 to 45°C; a step (C) for loosening the cooked rice cooled in step (B) while causing the cooked rice to contact steam, and for adding water to the cooked rice at an amount of 2 to 11 mass% of the mass of the cooked rice; and a step (D) for freezing the cooked rice obtained in step (C). This method is useful in the manufacture of frozen cooked rice as a good method for individual quick freezing of frozen cooked rice.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to an earlier filed Japanese patent application, Patent Application No. 2021-062125 (filing date: March 31, 2021), the entire disclosure of which is incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a method for producing a frozen cooked rice food product. [Background technology]

[0003] Cooked rice for freezing has traditionally been produced by various methods. In freezing cooked rice, additives, oils, etc. are used to make the rice more easily breakable, and then the rice is spread out on a conveyor and dropped onto it, where physical force is applied to break the rice into pieces. Specifically, one method involves smoothing the rice on a conveyor before freezing, and then using agitators or other devices to break the rice into individual grains after freezing. While this method produces a loose, flaky rice, the rice grains tend to break apart and become crumbly, failing to achieve a fluffy appearance or plump texture. Furthermore, the use of additives and oils affects the flavor and taste of the rice, resulting in a deterioration in quality, which is particularly noticeable when the rice is eaten raw.

[0004] For this reason, efforts are underway to develop a method for freezing frozen cooked rice foods that does not use additives or fats and that breaks the food into pieces (breaking it apart), and that differs from the method of physically breaking it apart (breaking it apart).

[0005] For example, Patent Document 1 discloses a method for producing loose frozen cooked rice food using a coating liquid.

[0006] However, there is still a demand for a frozen cooked rice food product that can be frozen in a better state without using additives or fats and oils, and a method for producing the same. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-192475 Summary of the Invention

[0008] The present disclosure provides a frozen cooked rice food product that has an improved state of crumbling when the cooked rice food product is frozen after production, and a method for producing the same.

[0009] The present inventors have discovered a method for producing a frozen cooked rice food product, comprising: (A) a step of cooking raw material rice to obtain cooked rice; (B) a step of cooling the surface of the cooked rice cooked in step (A) to a temperature range of -1 to 45°C; (C) a step of loosening the cooked rice cooled in step (B) while bringing the cooked rice into contact with steam, and attaching water to the cooked rice in an amount of 2 to 11% by mass relative to the mass of the cooked rice; and (D) a step of freezing the cooked rice obtained in step (C). DETAILED DESCRIPTION OF THE INVENTION

[0010] According to one embodiment of the present disclosure, a method for producing a frozen cooked rice food product comprises the steps of: (A) cooking raw material rice to obtain cooked rice; (B) cooling the surface of the cooked rice cooked in step (A) to a temperature range of -1 to 45°C; (C) loosening the cooked rice cooled in step (B) while exposing the cooked rice to steam and attaching 2 to 11% by mass of water to the cooked rice; and (D) freezing the cooked rice obtained in step (C). The method of the present disclosure enables satisfactory break-up freezing of frozen cooked rice without using additives or oils and fats, or even with reduced amounts of these additives and oils and fats. This means that frozen cooked rice can be prepared without any deterioration in the quality of the rice, such as its flavor, which is an advantage of the method of the present disclosure.

[0011] In the present disclosure, raw rice (raw rice) refers to rice that has been threshed and dehusked, but has not yet been soaked in water. The raw rice is not particularly limited as long as it is suitable for use as a raw material for cooked rice foods. The type of rice, whether it is polished, and the degree of polishing can be appropriately selected depending on the type of cooked rice food. Examples of rice that can be used include Japonica and Indica varieties, with Japonica varieties being preferred for the raw rice in the present disclosure. Non-glutinous rice can also be used for the raw rice in the present disclosure. Furthermore, the amylose content (the proportion of amylose in the total amount of starch contained in rice) of the raw rice in the present disclosure is preferably 9% by mass or more. Unpolished rice (unpolished rice), germ rice (with the germ still intact), and polished white rice can all be used. The raw rice may also contain grains other than rice, as long as the effects of the present invention are not impaired. Examples of grains other than rice include wheat, barley (rolled barley, rice grain barley, glutinous barley, etc.), Job's tears, millet, barley, sorghum, black sesame, and white sesame.

[0012] Before cooking, the raw material rice is subjected to pretreatment such as washing and soaking as necessary. For example, the raw material rice is washed in water, soaked in water for at least one hour, drained, and then cooked by cooking, for example. In this disclosure, "cooking rice" may include not only cooking by cooking rice (cooking in a rice cooker), but also cooking using a steamer (for home use) or a rice steamer (for industrial use).

[0013] The raw rice is cooked in the usual way by heating the raw rice while it is immersed in water.

[0014] The device for cooking the raw rice is not particularly limited as long as the effects of the present disclosure are achieved, but any known rice cooking device can be used, whether for industrial or home use.

[0015] In this disclosure, cooked rice refers to rice obtained by cooking raw material rice, and includes not only cooked rice obtained by cooking polished rice or brown rice, but also barley rice obtained by cooking polished rice together with barley. Raw rice and polished rice are preferred as raw material rice in this disclosure, and polished rice of non-glutinous varieties is more preferred. Furthermore, in this disclosure, cooked rice refers to rice that has not been seasoned or processed, and therefore, frozen cooked rice foods in this disclosure refer to frozen cooked rice foods that have not been seasoned or processed. White rice obtained by cooking polished rice is preferred as cooked rice in this disclosure.

[0016] In the manufacturing method of the present disclosure, the surface of cooked rice is cooled to a temperature in the range of −1 to 45° C. The cooling temperature is not particularly limited as long as it is within the range of −1 to 45° C., but a range of −1 to 20° C. is preferred, and a range of −1 to 10° C. is more preferred.

[0017] In the manufacturing method of the present disclosure, steam is brought into contact with cooled cooked rice, thereby adhering 2 to 11% by mass of water relative to the mass of the cooked rice. The mass ratio of the adhering water to the mass of the cooked rice is not particularly limited as long as it is within the range of 2 to 11% by mass, but is preferably in the range of 2 to 7% by mass, and more preferably in the range of 3 to 6% by mass.

[0018] In the manufacturing method of the present disclosure, the "steam" is not particularly limited as long as the effects of the present disclosure are achieved, but is preferably water vapor.

[0019] The mass ratio of steam mentioned above refers to the mass ratio of water that has actually adhered to the cooled cooked rice. For example, and not by way of limitation, if 5 g of water adheres to 100 g of cooled cooked rice, making the total mass 105 g, the mass ratio of water to the mass of cooked rice is 5% by mass.

[0020] In the manufacturing method of the present disclosure, the "step of loosening cooked rice while contacting with steam" is not particularly limited as long as the effects of the present disclosure are achieved, but it is a step of causing condensation to form on the surfaces of the grains of cooled cooked rice by contacting with steam, and loosening the cooked rice while maintaining this condensed state; for example, it is preferable that the step be a step of loosening cooked rice while spraying steam.

[0021] The pressure at which the steam is sprayed may be adjusted within a range that allows the above-mentioned predetermined amount of water to adhere to the surface of the cooled cooked rice, and is not limited to a range of, for example, 0.1 to 0.5 MPa.

[0022] The difference between the surface temperature of the cooled cooked rice and the temperature of the sprayed steam is not limited, but is preferably in the range of 60 to 101°C, for example.

[0023] In the manufacturing method of the present disclosure, the "process of loosening cooked rice" is not particularly limited as long as the effects of the present disclosure are achieved, but examples include a process of loosening cooked rice by physically contacting a stirring rod, comb teeth, or rotating teeth with the cooked rice, a process of loosening cooked rice by vibration with a vibrating conveyor, a process of loosening cooked rice while stirring by rotating it in a rotating container, a process of loosening cooked rice by dropping the cooked rice over a drop such as between conveyors, and a process of loosening cooked rice by applying air pressure. The above processes may be performed alone or in combination. In the manufacturing method of the present disclosure, the "process of loosening cooked rice" does not include a process of kneading cooked rice or a process of crushing cooked rice. Furthermore, in the manufacturing method of the present disclosure, physical parameters such as the vibration frequency, rotation speed, and air pressure may be adjusted within a range that allows for break-up freezing. In the manufacturing method of the present disclosure, the "step of loosening cooked rice" preferably refers to one or more steps selected from a step of loosening cooked rice with a spatula, stick, and / or comb teeth equipped with a stirring mechanism and / or a rotating mechanism, a step of loosening cooked rice with a conveying device equipped with a vibration mechanism, a step of loosening cooked rice by dropping the cooked rice when transferring to a subsequent conveying device during transport by the conveying device, and a step of loosening cooked rice by air pressure.

[0024] In the manufacturing method of the present disclosure, the "step of loosening cooked rice" is not particularly limited as long as the effects of the present disclosure are achieved. 2 and loosening the cooked rice by spreading it out or while spreading it out so that 100 g of the cooked rice is packed into a space of 0.1 to 3.0 cm in height.

[0025] In the manufacturing method of the present disclosure, cooled cooked rice is exposed to a predetermined amount of steam to cause condensation to form on the surfaces of the cooled cooked rice grains, and the cooked rice is loosened while maintaining the condensation, and the resulting cooked rice is frozen. This makes it possible to break down the cooked rice into single rice grains and multiple grain lumps in which multiple rice grains are connected to each other, and to freeze the rice in this multiple grain lumps.

[0026] In order to serve cooked rice neatly in a rice bowl, in the manufacturing method of the present disclosure, the major axis of the multi-grain agglomerate is preferably 46 mm or less, and the weight of the multi-grain agglomerate is preferably 10 g or less, and more preferably 8.7 g or less.

[0027] In the present disclosure, the number of particles per agglomerate in the multi-particle agglomerate is preferably 229 or less, and more preferably 199 or less.

[0028] In the multi-grain mass obtained in this manner, it is preferable that 60% or more of the total rice grains are multi-grain masses of 26 or more grains, and 90% or more of the total rice grains are multi-grain masses of 100 or less grains.

[0029] In the manufacturing method of the present disclosure, the cooked rice food can be frozen using a known method, and can be appropriately selected depending on the type of cooked rice food, etc. Preferably, the cooked rice food can be made into a frozen food form by rapid freezing at -30°C or below. Furthermore, the obtained frozen food is stored at -15°C or below, preferably -18°C or below.

[0030] The frozen cooked rice food of the present disclosure can be eaten by subjecting it to various heating treatments, such as in a microwave oven, a frying pan, or in a hot water bath.

[0031] Furthermore, according to one embodiment of the present disclosure, the following (1) to (8) can be provided. (1) A method for producing a frozen cooked rice food product, (A) A process of cooking raw rice to obtain cooked rice; (B) a step of cooling the surface of the cooked rice in step (A) to a range of -1 to 45°C; (C) loosening the cooked rice cooled in step (B) while bringing the cooked rice into contact with steam, and adhering 2 to 11% by mass of water to the cooked rice; and (D) a step of freezing the cooked rice obtained in step (C); The method comprising: (2) The method according to (1), wherein the cooked rice obtained in step (A) is white rice. (3) The method according to (1) or (2), wherein the surface of the cooked rice is cooled to a temperature within the range of −1 to 20° C. in step (B). (4) The method according to any one of (1) to (3), wherein the steam contacted in step (C) is water steam. (5) The method according to any one of (1) to (4), wherein the step of loosening the cooked rice in step (C) is one or more steps selected from the group consisting of a step of loosening the cooked rice with a spatula, a stick, and / or a comb equipped with a stirring mechanism and / or a rotating mechanism, a step of loosening the cooked rice with a conveying device equipped with a vibration mechanism, a step of loosening the cooked rice by dropping the cooked rice when transferring to a subsequent conveying device during transport by the conveying device, and a step of loosening the cooked rice by air pressure. (6) The method according to any one of (1) to (5), wherein the step of loosening the cooked rice while contacting with steam in step (C) is a step of loosening the cooked rice while spraying steam. (7) The step of loosening the cooked rice in step (C) is carried out in a manner that the cooked rice has an area of ​​100 to 300 cm 2 and loosening the cooked rice by spreading it or while spreading it so that 100 g of the cooked rice is packed into a space having a height of 0.1 to 3.0 cm. (8) The method according to any one of (1) to (7), wherein the mass of the water to be attached to the cooked rice in step (C) is 2 to 7% by mass relative to the mass of the cooked rice. [Example]

[0032] The present disclosure will be specifically described below, but is not limited to these examples. Unless otherwise specified, units and measurement methods follow the provisions of the Japanese Industrial Standards (JIS).

[0033] 600g of polished rice was prepared, washed in the usual way, soaked for over an hour, and then water was added to make a total of 1350g of polished rice and water, and cooked in an induction rice cooker. After cooking, 300g of the rice was placed on a 600cm mesh (2mm inner diameter grid). 2 The rice was spread out to a thickness of about 1.5 cm and cooled in a refrigerator to below 10°C. Using a steam cleaner SC4 EasyFix (maximum discharge pressure: 0.35 MPa, sprayed steam weight approximately 1.1 g / sec) (Kärcher), 5% by mass of steam was sprayed onto the rice while it was loosened lengthwise with a rubber spatula. During this process, the moisture from the steam was allowed to circulate between the grains of rice, and the rice was loosened with the rubber spatula without being crushed. The rice was then transferred to a tray and flash-frozen.

[0034] 250g of frozen rice was measured to determine the distribution of multi-grain agglomerates. The results are shown below.

[0035] The distribution of the multi-grain mass was such that 90% or more of all rice grains had 3 or more grains, 80% or more of all rice grains had 6 or more grains, 70% or more of all rice grains had 12 or more grains, and 60% or more of all rice grains had 26 or more grains. Also, the distribution was such that 90% or more of all rice grains had 100 grains or less, 80% or more of all rice grains had 77 grains or less, 70% or more of all rice grains had 60 grains or less, and 60% or more of all rice grains had 53 grains or less.

[0036] 600g of polished rice was prepared, washed in the usual way, soaked for over an hour, and then water was added to make a total of 1350g of polished rice and water, and cooked in an induction rice cooker. After cooking, 300g of the rice was placed on a 600cm mesh (2mm inner diameter grid). 2 The rice was spread to a thickness of approximately 1.5 cm and cooled in a refrigerator to a temperature of -3 to 45°C. Using a steam cleaner SC4 EasyFix (maximum discharge pressure: 0.35 MPa, sprayed steam weight: approximately 1.1 g / sec) (Kärcher), the rice was sprayed with 1 to 11% by mass of steam and loosened vertically with a rubber spatula. The steam was distributed evenly between the grains, and the rice was loosened with the spatula without crushing. The rice was then transferred to a tray and flash-frozen. 150 g of this frozen rice was placed in a bowl, lightly covered with plastic wrap, and microwaved at 600 W for 2 minutes, after which it was evaluated for its ability to be broken up. Agglomerates with a major diameter of 46 mm or less were deemed breakable, while agglomerates with a major diameter of 47 mm or more were deemed unbreakable.

[0037] As a control, rice was prepared by spraying it with water and hot water instead of steam. After cooking, the rice was spread on a wire rack (2 mm inner diameter, grid pattern) and cooled in a refrigerator to below 10°C. The rice was then loosened with a spatula while spraying it with 20°C water and 90°C hot water using a spray bottle. The rice was then transferred to a tray and flash-frozen. 150g of this frozen rice was placed in a bowl, lightly covered with plastic wrap, and heated in a microwave at 600W for 2 minutes before use in the test.

[0038] As a control, rice was prepared using dry ice instead of steam. When 300g of rice spread on a wire rack was sprayed with snow dry ice for 10 seconds, clumps with a long diameter of 47mm or more were formed. Also, when 300g of loosened rice was dropped into the rack over 10 seconds while being sprayed with snow dry ice, large clumps with a long diameter of 47mm or more were formed.

[0039] The results are shown in Tables 1 to 4. When the multi-particle agglomerates were not broken down properly, with a major axis of 47 mm or more and a weight of 10.3 g or more, they could not be neatly placed in a rice bowl. On the other hand, when the major axis of the multi-particle agglomerates was 46 mm or less and a weight of 8.7 g or less, they could be neatly placed in a rice bowl.

[0040] [Table 1]

[0041] [Table 2]

[0042] [Table 3]

[0043] [Table 4]

[0044] The above results demonstrate that the method of the present disclosure enables good fragmentation freezing of frozen cooked rice. Compared to the frozen cooked rice obtained by the method of the present disclosure, the frozen cooked rice with a steam volume of 12% or more did not fragment well, and after heating in a microwave, the rice became soft and sticky due to the high moisture content, and did not have a good texture.

Claims

1. A method for producing a frozen cooked rice food product, comprising: (A) a step of cooking raw rice to obtain cooked rice; (B) a step of cooling the surface of the cooked rice in step (A) to a range of −1 to 45° C.; (C) loosening the cooked rice cooled in step (B) while bringing the cooked rice into contact with steam, and adhering 2 to 11% by mass of water to the cooked rice; and (D) A step of freezing the cooked rice obtained in step (C); The method comprising:

2. The method according to claim 1, wherein the cooked rice obtained in step (A) is white rice.

3. The method according to claim 1 or 2, wherein the temperature at which the surface of the cooked rice is cooled in step (B) is within the range of -1 to 20°C.

4. The method according to any one of claims 1 to 3, wherein the steam contacted in step (C) is water steam.

5. The method according to any one of claims 1 to 4, wherein the step of loosening the cooked rice in step (C) is one or more steps selected from a step of loosening the cooked rice with a spatula, a stick, and / or a comb equipped with a stirring mechanism and / or a rotation mechanism, a step of loosening the cooked rice with a conveying device equipped with a vibration mechanism, a step of loosening the cooked rice by dropping the cooked rice when transferring to a subsequent conveying device during transport by the conveying device, and a step of loosening the cooked rice by air pressure.

6. The method according to any one of claims 1 to 5, wherein the step of loosening the cooked rice while contacting with steam in step (C) is a step of loosening the cooked rice while spraying steam.

7. In step (C), the cooked rice is loosened by loosening the cooked rice in an area of ​​100 to 300 cm. ２ The method according to any one of claims 1 to 6, wherein the cooked rice is loosened by spreading or while spreading so that 100 g is packed into a space having a height of 0.1 to 3.0 cm.

8. The method according to any one of claims 1 to 7, wherein the mass of water attached to the cooked rice in step (C) is 2 to 7% by mass relative to the mass of the cooked rice.

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