Frozen food product containing cooked rice

Abstract

This frozen food product containing cooked rice contains cooked rice and a collagen peptide. The frozen food product has a high content of protein or a decomposition product thereof. The collagen peptide content of the frozen food product is at least 3 parts by mass per 100 parts by mass of uncooked rice used for the cooked rice. Preferably the frozen food product is obtained by a step for frying cooked rice. Also preferably the weight-average molecular weight of the collagen peptide is 3,000 or less. Also preferably the content of protein or a decomposition product thereof is at least 3 g per 100 g of the frozen food product containing cooked rice.

Description

Foods containing frozen cooked rice

[0001] The present invention relates to a food product containing frozen cooked rice.

[0002] Conventionally, frozen cooked rice-containing foods such as frozen fried rice have been widely popular because they can be easily eaten in a microwave oven, etc. Collagen peptides have been added to cooked rice-containing foods for the purpose of preventing aging or providing a loose texture (e.g., Patent Documents 1 and 2).

[0003] JP 2008-193907 A JP 2018-130041 A

[0004] In the case of frozen fried rice, frozen cooked rice-containing foods are required to have "umami," a flavor that plays an important role in determining the deliciousness of food. However, conventional frozen cooked rice-containing foods have not been sufficient in terms of umami. Furthermore, from the perspective of health, such as preventing or improving locomotive syndrome, it has been recommended in recent years to consume a lot of protein and its hydrolyzed products, and some consumers are seeking high-protein foods. Therefore, it is desirable that frozen cooked rice-containing foods that are consumed on a daily basis also meet these requirements.

[0005] An object of the present invention is to provide a frozen cooked rice-containing food product which has an excellent umami taste and a higher content of protein or a decomposition product thereof than conventional products.

[0006] The present invention provides a frozen cooked rice-containing food product containing cooked rice and collagen peptide, wherein the collagen peptide content is 3 parts by mass or more per 100 parts by mass of raw material rice for the cooked rice, and the frozen cooked rice-containing food product has a high content of protein or a degradation product thereof.

[0007] A preferred embodiment of the present invention is described below. The present invention relates to a frozen cooked rice-containing food product containing cooked rice and collagen peptide, which is a frozen cooked rice-containing food product with a high content of protein or its hydrolyzates, with the collagen peptide content being 3 parts by mass or more per 100 parts by mass of raw rice for the cooked rice. As described below, the cooked rice-containing food product preferably contains, in addition to cooked rice, other cooked grains other than cooked rice or ingredients other than cooked grains (hereinafter simply referred to as "ingredients"). The collagen peptide content here refers to the amount of collagen peptide contained in the entire frozen cooked rice-containing food product. Hereinafter, proteins or their hydrolyzates will also be collectively referred to as "proteins."

[0008] As described above, the collagen peptide is contained in the frozen cooked rice-containing food of the present invention in an amount of 3 parts by mass or more per 100 parts by mass of raw rice. Using such a large amount of collagen peptide allows the frozen cooked rice-containing food of the present invention to have a high protein content and improves the umami flavor resulting from the high protein content. To further enhance these effects, the content of collagen peptide in the frozen cooked rice-containing food is preferably 4 parts by mass or more, more preferably 6 parts by mass or more, and particularly preferably 7 parts by mass or more per 100 parts by mass of raw rice. Furthermore, to prevent deterioration in texture due to the flaky texture of the rice caused by using a large amount of proteins, the content of collagen peptide in the frozen cooked rice-containing food is preferably less than 23 parts by mass per 100 parts by mass of raw rice. To improve the flaky texture of the rice, the content is particularly preferably 20 parts by mass or less, particularly preferably 18 parts by mass or less, even more preferably 16 parts by mass or less, and most preferably 15 parts by mass or less.

[0009] One of the features of the present invention is that a food product containing frozen cooked rice contains collagen peptide as a means for increasing the protein content. Collagen peptide is obtained by heat-extracting collagen to obtain gelatin, and then hydrolyzing the gelatin with an enzyme or acid. The source of collagen is not limited, and collagen derived from bones and skin of pigs, cows, chickens, etc., or fish bones, skin, and scales can be used. Furthermore, the extraction method is not limited, and for example, hot water extraction, pressurized extraction, etc. can be used.

[0010] By using collagen peptides instead of high-molecular-weight substances such as proteins or gelatin, the present invention makes it possible to obtain frozen cooked rice-containing foods with high protein content while preventing deterioration in quality compared to conventional frozen cooked rice-containing foods with low protein content. Because collagen peptides can be soluble in water, they can be added and dissolved in water used for cooking rice, allowing a relatively large amount of protein to be contained in the frozen cooked rice-containing food.

[0011] Collagen, which is a raw material for collagen peptides, can be used without any particular limitations regarding the organism from which it is derived (pig, cow, fish, etc.) or the production method (acid treatment, alkali treatment, etc.). For example, the bones and skin of animals such as cows, pigs, and chickens, and the skin and scales of fish such as salmon, tuna, tilapia, and cod can be used.

[0012] The collagen peptide preferably has an average molecular weight of 3000 or less. By setting the average molecular weight to 3000 or less, it is easy to prevent the texture of cooked rice from becoming heavy even if it contains a lot of protein, and it is easy to obtain a flaky texture. It is also thought that collagen peptides with low molecular weights are more likely to obtain umami. From this perspective, the average molecular weight of collagen peptides is more preferably 2500 or less, even more preferably 2000 or less, even more preferably 1800 or less, and particularly preferably 1500 or less. Furthermore, if the average molecular weight of collagen peptides is too small, an undesirable taste (bitterness) specific to peptides may occur, so it is preferably 100 or more, more preferably 500 or more, and particularly preferably 1000 or more from the viewpoint of easy obtaining a flaky texture. In this specification, when simply referring to "average molecular weight," it refers to the weight average molecular weight. The weight-average molecular weight is measured using the method described in the "Edible Collagen Peptide Standards" established by the Japan Gelatin and Collagen Industry Association (https: / / www.gmj.or.jp / topics / 201215 / 201215.html, accessed December 25, 2023).

[0013] As described above, in this specification, the frozen cooked rice-containing food product may contain ingredients other than cooked rice. In particular, the collagen peptide content in the cooked rice of the frozen cooked rice-containing food product of the present invention is preferably 2.5 parts by mass or more per 100 parts by mass of raw rice, in order to more effectively improve the umami flavor due to the amount of proteins, more preferably 3 parts by mass or more, even more preferably 4 parts by mass or more, and most preferably 5 parts by mass or more. Furthermore, in order to prevent a decrease in texture due to the flaky texture of the rice caused by using a large amount of proteins, the content of collagen peptide in the cooked rice of the frozen cooked rice-containing food product is more preferably less than 20 parts by mass per 100 parts by mass of raw rice, particularly preferably 15 parts by mass or less, even more preferably 12 parts by mass or less, and most preferably 12 parts by mass or less. To achieve the aforementioned amount of collagen peptide in the cooked rice, the collagen peptide may be added to the aqueous liquid added to the rice during cooking. The collagen peptide in the cooked rice may penetrate the interior of the rice grains, or may coat or adhere to the surface.

[0014] In order to improve the umami flavor of the frozen cooked rice-containing food of the present invention, the protein content (protein or its hydrolyzates) is preferably 3 g or more, more preferably 4 g, even more preferably 5 g or more, and particularly preferably 7 g or more per 100 g of the frozen cooked rice-containing food. Furthermore, in order to achieve a higher protein content and improve the umami flavor due to the amount of protein, the protein content of the frozen cooked rice-containing food of the present invention is preferably 25 g or less, more preferably 20 g or less, particularly preferably 18 g or less, and most preferably 15 g or less. The protein content in a frozen cooked rice-containing food refers to the so-called "protein content" measured by the combustion method. For example, a sample can be prepared by crushing 250 g of the frozen cooked rice-containing food for 1 minute using a food processor (Retsch GM200 type), thawing it at room temperature, and then subjecting it to analysis.

[0015] In the present invention, frozen cooked rice-containing foods refer to foods whose main ingredient is cooked rice or other grains. The grains may include grains other than rice, such as barley, millet, barnyard millet, common millet, soybeans, adzuki beans, and sesame. The rice content of the grains in frozen cooked rice-containing foods is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. While there are no particular restrictions on the rice used as the main ingredient in frozen cooked rice-containing foods, it is preferable not to use low-protein rice in frozen cooked rice-containing foods in order to obtain the above-mentioned protein content. In this specification, low-protein rice refers to rice with a protein content of 1.0 g or less per 180 g of cooked rice.

[0016] As described above, frozen cooked rice-containing foods preferably contain ingredients in addition to cooked grains including cooked rice. Examples of ingredients include meat and vegetables. Specific examples are described below. By including ingredients, collagen peptides can be contained in the ingredients, increasing the amount of collagen peptide while suppressing adverse effects on the texture of the cooked rice and the manufacturing process, thereby improving the quality of the frozen cooked rice-containing food. From the viewpoint of increasing the nutritional value of protein and other nutrients, frozen cooked rice-containing foods preferably contain 10 parts by mass or more of ingredients per 100 parts by mass of cooked grains, and more preferably 15 parts by mass or more. Furthermore, from the viewpoint of suitability for, for example, fried rice, the frozen cooked rice-containing food preferably contains 40 parts by mass or less of ingredients per 100 parts by mass of cooked grains, and more preferably 30 parts by mass or less.

[0017] In the present invention, in addition to the preferred inclusion of collagen peptide in cooked rice, it is also preferred to include collagen peptide in ingredients, as this makes it easier to achieve both a flaky texture and delicious flavor. The reason for this is that when a certain amount or more of collagen peptide is included in cooked rice, the flaky texture tends to decrease. Therefore, it is thought that by including a certain amount of collagen peptide in the ingredients, the flaky texture can be more easily maintained. When the ingredients contain collagen peptide, the collagen peptide may penetrate the ingredients, or may coat or adhere to the surface of the ingredients. Examples of methods for incorporating collagen peptide into ingredients include heating ingredient materials in contact with a collagen peptide-containing liquid. Here, contact includes, for example, heating the ingredient materials in a mixed state with a collagen peptide-containing liquid. Examples of ingredient materials include unheated ingredients.

[0018] The collagen peptide contained in the ingredient in the step of heating the ingredient raw material in contact with a collagen peptide-containing liquid may have a molecular weight or origin different from that of the collagen peptide contained in the seasoning liquid during the rice cooking process, or may be a collagen peptide different from that. The collagen peptide contained in the ingredient is preferably contained in an amount of 3 parts by mass or more per 100 parts by mass of the ingredient raw material in the frozen cooked rice-containing food of the present invention, in order to more effectively improve the umami flavor due to the amount of proteins, more preferably 4 parts by mass or more, most preferably 6 parts by mass or more, and particularly preferably 8 parts by mass or more. Furthermore, in order to prevent deterioration in texture and the texture and flavor of the ingredient due to the use of a large amount of proteins, the content of collagen peptide in the ingredient in the frozen cooked rice-containing food is more preferably less than 20 parts by mass, particularly preferably 18 parts by mass or less, most preferably 15 parts by mass or less, and most preferably 13 parts by mass or less per 100 parts by mass of the ingredient raw material. Here, ingredient ingredients refer to solid ingredients other than rice, seasonings, and oils and fats, such as meat, fish, vegetables, and plant proteins.

[0019] In order to more effectively achieve a flaky texture and delicious flavor, the mass ratio of the amount of collagen peptide contained in the cooked rice to the amount contained in the ingredients in the frozen cooked rice food product is preferably 100:20 to 150, more preferably 100:30 to 100, still more preferably 100:30 to 90, and particularly preferably 100:30 to 70.

[0020] The frozen cooked rice-containing food of the present invention contains cooked grain rice as a main ingredient. "Containing cooked grain rice as a main ingredient" means that the food contains 40% by mass or more of cooked grain rice, preferably 50% by mass or more, and more preferably 60% by mass or more. In particular, the frozen cooked rice-containing food of the present invention preferably contains 40% by mass or more of cooked rice, more preferably 50% by mass or more, and even more preferably 60% by mass or more.

[0021] Examples of frozen cooked rice-containing foods include fried rice, chicken rice, pilaf, dry curry, bibimbap, jambalaya, nasi goreng, garlic rice, and butter rice, which are produced by stir-frying rice or cooked rice, and takikomi gohan (seasoned rice), maze gohan (mixed rice), and the like, which are produced without stir-frying rice or cooked rice.

[0022] In the present invention, frozen cooked rice-containing foods produced by frying rice or cooked rice are particularly preferred because they are widely preferred and are therefore highly economical, and the flavor of collagen peptides can be easily masked. In particular, frozen cooked rice-containing foods produced by frying cooked rice are preferred because they are more likely to have a flaky texture. In particular, frozen cooked rice-containing foods are preferably produced by heating rice or cooked rice with collagen peptides. The inventors believe that collagen peptides themselves before the heating process have umami, but further believe that amino acids are produced by the decomposition of peptides primarily due to thermal history during processes such as cooking rice, heating ingredients, and frying, which ultimately leads to improved umami. From this perspective, frozen cooked rice-containing foods are particularly preferably produced by frying rice or cooked rice with collagen peptides. Because the frying process is usually carried out at high temperatures, frozen cooked rice-containing foods produced by frying rice or cooked rice with collagen peptides are thought to be more likely to have umami. In particular, in the present invention, in order to successfully obtain a large amount of collagen peptide with a flaky texture, it is preferable that the rice is obtained by frying cooked rice with collagen peptide. Here, the process of frying cooked rice with collagen peptide includes both the process of adding collagen peptide when cooking the rice and then frying the resulting cooked rice, and the process of frying the collagen peptide added to the ingredients and the cooked rice. In the present invention, it is preferable that the rice is produced by adding collagen peptide when cooking the rice and then mixing the resulting cooked rice with ingredients and frying it, and in particular, it is preferable that the rice is produced by mixing cooked rice to which collagen peptide has been added with ingredients to which collagen peptide has been added and frying it when cooking the rice, as this makes it easier to achieve a balance between umami and flaky texture.

[0023] The moisture content of the frozen cooked rice-containing food is preferably 40% by mass or more, more preferably 45% by mass or more, and particularly preferably 50% by mass or more. A frozen cooked rice-containing food with a moisture content of a certain level or more is preferred because it can stably contain collagen peptides. The moisture content of the frozen cooked rice-containing food is preferably, for example, 60% by mass or less, as this facilitates a flaky texture, more preferably 57% by mass or less, and particularly preferably 55% by mass or less. The moisture content of the frozen cooked rice-containing food can be measured by a normal pressure heating and drying method, in which the food is dried overnight at 105°C under normal pressure. For the normal pressure heating and drying method, a sample for this measurement can be prepared, for example, by crushing 250 g of the frozen cooked rice-containing food using a food processor (Retsch GM200 type) for 1 minute, then thawing at room temperature and subjecting it to analysis.

[0024] The lipid content of the frozen cooked rice-containing food is preferably 15% by mass or less, more preferably 11% by mass or less, even more preferably 10% by mass or less, and particularly preferably 9% by mass or less. A frozen cooked rice-containing food with a lipid content of a certain level or less is preferred because it can stably contain collagen peptides. The lipid content of the frozen cooked rice-containing food is preferably 4% by mass or more, more preferably 5% by mass or more, and particularly preferably 6% by mass or more. The lipid content of the frozen cooked rice-containing food can be measured by acid hydrolysis. A sample preparation method for this measurement includes grinding 250 g of the frozen cooked rice-containing food for 1 minute using a food processor (Retsch GM200 type), thawing it at room temperature, and then subjecting it to analysis.

[0025] The carbohydrate content of the frozen cooked rice-containing food is preferably 20 to 40% by mass, and particularly preferably 25 to 35% by mass. The carbohydrate content is a value obtained by subtracting from 100 the amount of lipids measured by the acid hydrolysis method, the amount of protein measured by the combustion method, the amount of moisture measured by the atmospheric heating and drying method, and the ash content.

[0026] The frozen cooked rice-containing food of the present invention can contain protein components other than collagen peptide. As the protein component, the frozen cooked rice-containing food preferably contains granular soy protein. Combining collagen peptide, a water-soluble protein component, with water-insoluble granular soy protein makes it easier to achieve a flaky texture, umami, and high protein content. Because granular soy protein is water-insoluble, it cannot be contained in large amounts in frozen cooked rice-containing foods, but it is less likely to adversely affect the texture of the cooked rice. Furthermore, granular soy protein has the ability to retain seasoning liquid, which, when stir-fried, plays a role in adjusting the flavor and flaky texture of the cooked rice. Thus, collagen peptide and granular soy protein complement each other's weaknesses, and combining the two can produce a frozen cooked rice-containing food of excellent quality. In particular, frozen cooked rice-containing foods preferably contain granular soy protein that has been immersed in a collagen peptide-containing liquid. Such granular soy protein is believed to be able to retain collagen peptide within the porous body, allowing it to contain a larger amount of collagen peptide without reducing the flaky texture of the cooked rice.

[0027] Granular soy protein typically refers to granular vegetable proteins defined in the "Japanese Agricultural Standards for Vegetable Proteins" (Ministry of Agriculture, Forestry and Fisheries Notification No. 489, February 24, 2016), in which the main vegetable protein ingredient is soybeans or defatted soybeans. Examples include those obtained by using one or more ingredients selected from defatted soybeans, soy flour, soy milk powder, defatted soy milk powder, concentrated soy protein, isolated soy protein, etc., and then structuring and molding these using a twin-screw extruder or the like. The shape refers to those formed into granules or flakes and having a meat-like texture.

[0028] The granular soy protein used in the present invention may be either dried or frozen, but it is preferable to use a dried product. Furthermore, the size of the granular soy protein is preferably an average length of 10 grains of 0.5 to 20 mm, more preferably 1 to 10 mm, in order to allow the soy protein to absorb seasoning liquid well. The term "length" as used herein refers to the length of the longest line segment that crosses the shape (contour shape) as viewed from any direction. Specific commercially available products include "New Soyme" and "New Comitex" manufactured by Nisshin Oillio Group, Inc., and "New Fujinic" and "Fujinic Ace" manufactured by Fuji Oil Co., Ltd.

[0029] When the frozen cooked rice-containing food contains granular soy protein, the amount used is preferably 15 to 100 parts by mass, more preferably 25 to 95 parts by mass, even more preferably 25 to 85 parts by mass, even more preferably 30 to 60 parts by mass, and most preferably 40 to 60 parts by mass, based on 100 parts by mass of collagen peptide. Furthermore, when the frozen cooked rice-containing food contains granular soy protein, the amount used is preferably 0.2 to 4.0% by mass, more preferably 0.5 to 3.0% by mass, and most preferably 1.0 to 2.0% by mass, based on the dry mass of all ingredients of the frozen cooked rice-containing food.

[0030] A preferred method for producing the frozen cooked rice-containing food of the present invention will be described below. The following description of the production method can be appropriately adopted as a description of the above-mentioned frozen cooked rice-containing food.

[0031] This production method includes a first step of cooking rice in a liquid (aqueous liquid) containing collagen peptide. More preferably, this production method includes a first step of cooking rice in a liquid (aqueous liquid) containing collagen peptide, a step of frying the cooked rice obtained in the first step, and a step of freezing the fried cooked rice. Particularly preferably, this production method includes a first step of cooking rice in a liquid (aqueous liquid) containing collagen peptide, a second step of heating ingredients in a seasoning liquid, and a third step of frying the ingredients heated in the seasoning liquid together with the cooked rice obtained in the first step at a temperature of 100 to 300°C, and further includes a step of freezing the fried ingredients and cooked rice. It is preferable that the seasoning liquid contains collagen peptide, as this makes it easier to achieve both a flaky texture and a delicious flavor. Furthermore, either the first step or the second step may be performed first, or they may be performed simultaneously.

[0032] In the first step, rice is cooked in a liquid containing collagen peptide. The collagen peptide content in the liquid containing collagen peptide may be the entire amount of collagen peptide contained in the frozen rice-containing food of the present invention, or may be a portion of the collagen peptide contained in the frozen rice-containing food of the present invention. However, a portion of the collagen peptide contained in the frozen rice-containing food of the present invention is preferred in terms of achieving both a flaky texture and a delicious taste. Preferably, the collagen peptide in the liquid containing collagen peptide accounts for 50% by mass or more of the collagen peptide contained in the frozen rice-containing food of the present invention, which is preferable in terms of improving the flavor of the resulting frozen rice-containing food and making it easy to contain a high protein content, more preferably 60% by mass or more, and particularly preferably 65% ​​by mass or more. In the first step, using granular collagen peptide is particularly preferable in terms of increasing water solubility. Here, granulation methods for producing granules include fluidized bed granulation, stirring granulation, tumbling granulation, spray drying, extrusion granulation, tumbling granulation, and coating granulation, with granulation by spray drying being preferred in terms of high solubility. The amount of water used during rice cooking is preferably adjusted to within a range of, for example, 50 to 150 parts by mass, particularly 70 to 120 parts by mass, per 100 parts by mass of raw material rice.

[0033] The ingredients used in the second step include meat and / or vegetables. Examples of meat include beef, pork, chicken, and other livestock meats, fish, shellfish, squid, octopus, crab, and other meats. The vegetables in the meat and / or vegetables used in the second step are not particularly limited, and examples include carrots, bell peppers, onions, paprika, cabbage, lettuce, Chinese cabbage, parsley, mitsuba, watercress, radish, spinach, mizuna, komatsuna, chrysanthemum, shiso, Japanese leek, Kujo leek, celery, chives, bean sprouts, radish sprouts, asparagus, butterbur, bell peppers, tomatoes, okra, avocado, papaya, daikon radish, burdock, turnip, sweet potato, potato, eggplant, Chinese yam, myoga, shallot, taro, broccoli, cauliflower, mushrooms, garlic, ginger, bok choy, green peas, cilantro, water spinach, and arrowhead.

[0034] In the second step, it is preferable to heat the ingredients in a seasoning liquid. By doing so, the flavor of the seasoning liquid is sufficiently retained in the ingredients. It is also preferable that the seasoning liquid used to heat the ingredients contains collagen peptide. By including collagen peptide in both the ingredients and cooked rice, the effect of high protein content is fully obtained, and if the collagen peptide has a flavor due to its origin, this flavor is preferably masked by the seasoning liquid. The heating temperature is preferably 50 to 100°C. After heating, the ingredients are preferably lightly drained and then subjected to the third step. The amount of liquid (including the seasoning liquid) used in the second step is preferably adjusted to, for example, 50 to 150 parts by weight, particularly 70 to 120 parts by weight, per 100 parts by weight of the ingredients.

[0035] As mentioned above, it is preferable that the frozen cooked rice-containing food contains granular soy protein, and it is also preferable that the ingredients heated in the seasoning liquid in the second step contain granular soy protein, as this makes it easier to achieve both the flaky texture of cooked rice, the high protein content, and umami. The granular soy protein retains an appropriate amount of seasoning liquid, and therefore also plays a role in flavoring the stir-frying step.

[0036] Next, in the third step, the cooked rice obtained in the first step is fried with the ingredients and cooked rice obtained in the second step. This step is carried out at 100°C or higher, and is preferably carried out so that the maximum temperature reaches 150 to 300°C, in order to obtain a flaky texture and to easily obtain umami. In addition, in the frying step, it is preferable to fry liquid egg or a diluted liquid egg in advance and then fry the ingredients and cooked rice together with the liquid egg, in order to coat the ingredients and rice with the liquid egg, imparting a moderate flaky texture and egg flavor, and to bring together the flavor of the entire frozen cooked rice-containing food. The frying time is usually preferably 30 seconds to 15 minutes, and more preferably 1 to 10 minutes.

[0037] Furthermore, the present invention provides a frozen cooked rice-containing food produced by the method described herein. The inventors have discovered that, according to the description herein, a frozen cooked rice-containing food having umami can be obtained, and in particular, a flaky texture and a good umami can be achieved at the same time. However, defining the physical properties related to flavor and texture requires the establishment of a new analytical method, and such analysis requires a huge amount of time. Thus, in this application, there were circumstances that made it impossible or impractical to define a frozen cooked rice-containing food as a product configuration beyond the description herein.

[0038] The present invention has been described above based on its preferred embodiments, but the present invention is not limited to the above description.

[0039] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

[0040] (Test Example 1) (Example 1) (First Step) 1.96 parts of water was mixed with 0.015 parts of salt, 0.07 parts of sodium glutamate, and 0.6 parts of collagen peptide (weight average molecular weight: 1,000-1,500, granular collagen peptide derived from bovine hide, Jolita "Peptiplus XB Lv", collagen peptide purity 100% by mass, produced by spray drying) to prepare 2.6 parts of rice cooking seasoning. 7.4 parts of rice was soaked in water and then drained to increase the weight of the rice to 9.2 parts. 2.6 parts of rice cooking seasoning, 0.3 parts of rice cooking oil, and 3.9 parts of water were added to the resulting soaked rice, and the rice was cooked. (Second Step) A steam kneader capable of heating by injecting heated steam into a stirring vessel was used as the mixing and heating device. In the kneader, 4 parts oil, 11 parts garlic paste, and 100 parts pork belly were heated and fried. A total of 120 parts Chinese cabbage, carrots, kimchi, and chives, 74 parts seasoning liquid, 59 parts water and collagen peptide mixture, and 45 parts vegetable protein (granular soy protein, Fuji Oil Co., Ltd.'s "New Fujinic 52S," 10 grains with an average length of 6 mm) were added and heated to 70-80°C while stirring. After heating and stirring, the steam was turned off, the mixture was cooled with water, lightly drained in a colander, and transferred to a tray to obtain a cooked ingredient. The blend ratio of the 74 parts seasoning liquid was 3 parts garlic seasoning, 40 parts fermented liquid seasoning, 18 parts sake, mirin, and other ingredients, 5 parts soy sauce ingredients, 2.5 parts salt, and 5.5 parts sugar (the protein content of the seasoning liquid was 2.9 parts as analyzed by the above method). 59 parts of the mixture of water and collagen peptide contained 23 parts of collagen peptide (weight average molecular weight: 1,000 to 1,500, granular collagen peptide derived from bovine (hide), Jolita "Peptiplus XB Lv", collagen peptide purity 100% by mass).

[0041] (Step 3) In a frying device, 0.7 parts of frying oil was added and 2.4 parts of diluted egg were fried. Then, 15 parts of the seasoned cooked rice obtained in Step 2, 3.15 parts of the cooked ingredients, and a total of 0.95 parts of flavor oil and seasonings (including powdered seasonings) were added and fried at 100-300°C, with a maximum temperature of 150-300°C, for approximately 5 minutes. Next, 0.4 parts of green onion was added and mixed, followed by cooling and flash freezing. The mixture was then bagged and further frozen to obtain frozen fried rice (frozen cooked rice-containing food). Per 100 g of the resulting frozen cooked rice-containing food, the protein content (protein or its hydrolyzate content) measured by the combustion method was 9.6 g, the lipid content measured by the acid hydrolysis method was 6.4 g, the moisture content measured by the atmospheric heat drying method was 53.4 g, and the carbohydrate content was 29.7 g. The collagen peptide content of the frozen cooked rice-containing food is shown in Table 1. If the collagen peptide added to the rice-cooking seasoning is contained in the cooked rice, the amount of collagen peptide contained in the cooked rice is calculated to be 8 parts by mass per 100 parts by mass of raw material rice. If the collagen peptide used in the second step is contained in the ingredients, the mass ratio of the amount of collagen peptide contained in the cooked rice to the amount of collagen peptide contained in the ingredients is calculated to be 100:33.

[0042] (Example 2) The amount of collagen peptide used in the first step of Example 1 was reduced from 0.6 parts by mass to 0.24 parts by mass, and the amount of water used to prepare the rice cooking seasoning liquid was increased accordingly. Frozen fried rice was obtained in the same manner as in Example 1, except for this point. The collagen peptide content in the frozen cooked rice-containing food is shown in Table 1. The amount of collagen peptide contained in cooked rice was calculated to be 3 parts by mass per 100 parts by mass of raw material rice. Furthermore, assuming that the collagen peptide used in the second step is contained in the ingredients, the mass ratio of the amount of collagen peptide contained in cooked rice to the amount of collagen peptide contained in the ingredients was calculated to be 100:83.

[0043] (Example 3) The amount of collagen peptide used in the first step of Example 1 was increased from 0.6 parts by mass to 0.9 parts by mass, and the amount of water used to prepare the rice cooking seasoning liquid was reduced accordingly. Frozen fried rice was obtained in the same manner as in Example 1, except for this point. The collagen peptide content in the frozen cooked rice-containing food is shown in Table 1. The amount of collagen peptide contained in cooked rice was calculated to be 12 parts by mass per 100 parts by mass of raw material rice. Furthermore, assuming that the collagen peptide used in the second step is contained in the ingredients, the mass ratio of the amount of collagen peptide contained in cooked rice to the amount of collagen peptide contained in the ingredients was calculated to be 100:22.

[0044] (Example 4) The amount of collagen peptide used in the first step of Example 1 was increased from 0.6 parts by mass to 1.5 parts by mass, and the amount of water used to prepare the rice cooking seasoning liquid was reduced accordingly. Frozen fried rice was obtained in the same manner as in Example 1, except for this point. The collagen peptide content in the frozen cooked rice-containing food is shown in Table 1. The amount of collagen peptide contained in cooked rice was calculated to be 20 parts by mass per 100 parts by mass of raw material rice. Furthermore, assuming that the collagen peptide used in the second step is contained in the ingredients, the mass ratio of the amount of collagen peptide contained in cooked rice to the amount of collagen peptide contained in the ingredients was calculated to be 100:13.

[0045] 250 g of the frozen fried rice obtained in each example was thawed in a 600 W microwave oven, and five adult panelists (3 men and 2 women) ate and evaluated the food according to the following criteria. The average scores are shown in Table 1.

[0046] (Texture) 5: The rice grains are separated and have a loose texture. 4: There are small clumps of rice grains, but the texture is loose. 3: There are large clumps of rice grains, but the texture is loose. 2: The texture is not as moist as cooked rice, but is not loose. 1: The texture has more moisture than cooked rice.

[0047] (Umami) 5: Very strong umami taste. 4: Strong umami taste. 3: Umami taste. 2: Not much umami taste. 1: No umami taste.

[0048]

[0049] As shown in Table 1, the frozen cooked rice-containing food of the present invention had a high content of protein or its hydrolyzates and a good umami taste. It was also found that there is a preferred range of collagen peptide content to obtain a flaky texture of rice.

[0050] (Test Example 2) (Example 5) The same procedure as in the first step of Example 1 was carried out. Specifically, 1.96 parts of water was mixed with 0.015 parts of salt, 0.07 parts of sodium glutamate, and 0.6 parts of collagen peptide (weight average molecular weight: 1,000-1,500, granular collagen peptide derived from bovine hide, Jolita "Peptiplus XB Lv", collagen peptide purity: 100% by mass) to prepare 2.6 parts of rice cooking seasoning. 7.4 parts of rice was soaked in water and then drained to increase the weight of the rice to 9.2 parts. 2.6 parts of rice cooking seasoning, 0.3 parts of rice cooking oil, and 3.9 parts of water were added to the resulting soaked rice, and the rice was cooked. The resulting cooked rice was frozen to obtain a frozen sample.

[0051] (Example 6) Collagen peptide (weight average molecular weight 2000, granular collagen peptide derived from pigskin, "Verisol P" manufactured by Jolita Co., Ltd., purity of collagen peptide 100% by mass) was used instead of the collagen peptide used in Example 5. Except for this, a frozen sample was obtained in the same manner as in Example 5.

[0052] (Example 7) Collagen peptide (weight average molecular weight: 5,000 to 8,000, granular collagen peptide derived from pigskin, Nitta Gelatin Co., Ltd. "SCP-5200", collagen peptide purity: 100% by mass) was used instead of the collagen peptide used in Example 5. Except for this, a frozen sample was obtained in the same manner as in Example 5.

[0053] 250 g of the frozen samples obtained in Examples 5 to 7 were thawed in a microwave oven at 600 W, and three adult panelists (two men and one woman) ate and evaluated the samples according to the following criteria. The average scores are shown in Table 2.

[0054] (Texture) 5: The rice grains are separated and loose. 4: There are small clumps of rice grains, but the texture is loose. 3: There are large clumps of rice grains, but the texture is somewhat loose. 2: The texture is sticky and moist, but not as moist as cooked rice. 1: The texture is sticky and has more moisture than cooked rice.

[0055] (Umami) 5: Strong umami taste. 4: Slight umami taste. 3: Umami taste. 2: Almost no umami taste. 1: No umami taste.

[0056]

[0057] As shown in Table 2, when collagen peptides with a weight-average molecular weight of 1,000 to 3,000 were used, the umami taste was good, and when collagen peptides with a weight-average molecular weight of 1,000 to 1,500 were used, the umami taste was even better. It was also found that the loosening feeling of rice during cooking was good when the molecular weight was in the range of 1,000 to 8,000. Therefore, from the viewpoint of improving the texture while enhancing the umami taste, it was found that the molecular weight is preferably 1,000 to 3,000, and particularly 1,000 to 1,500.

[0058] The present invention can provide a frozen cooked rice-containing food product that is excellent in umami taste and has a higher content of protein or its degradation products than conventional foods.

Claims

1. A frozen rice-containing food containing cooked rice and collagen peptide, wherein the content of collagen peptide is 3 parts by mass or more based on 100 parts by mass of the raw rice of the cooked rice, and the frozen rice-containing food is highly enriched with protein or its degradation product.

2. The frozen rice-containing food according to claim 1, wherein the content of collagen peptide is 20 parts by mass or less based on 100 parts by mass of the raw rice of the cooked rice.

3. The frozen rice-containing food according to claim 1, further containing meat and / or vegetables.

4. The frozen rice-containing food according to claim 1 or 2, which is obtained through a step of stir-frying the cooked rice.

5. The frozen rice-containing food according to claim 3, which is obtained through a step of adding collagen peptide to the meat and / or vegetables.

6. The frozen rice-containing food according to claim 1 or 2, wherein the average molecular weight of the collagen peptide is 3000 or less.

7. The frozen rice-containing food according to claim 1 or 2, wherein the content of protein or its degradation product is 3 g or more per 100 g of the frozen rice-containing food.

8. The frozen rice-containing food according to claim 1 or 2, further containing granular soy protein.

9. The frozen rice-containing food according to claim 1 or 2, wherein the water content is 40% by mass or more and 60% by mass or less.

10. The frozen rice-containing food according to claim 1 or 2, wherein the lipid content is 4% by mass or more and 15% by mass or less.

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