Frozen food manufacturing method

Abstract

To provide a method for producing frozen food suitable for freezing rice cooked with an antifreeze protein. [Solution] This is a method for producing frozen foods, which includes a rice cooking process (S104) in which rice is cooked using water to which antifreeze protein has been added, a molding process (S106) in which the rice obtained in the rice cooking process is shaped into sari balls, a freezing process (S107) in which the sari balls obtained in the molding process are frozen, and a glazing process (S108) in which a mist of liquid is sprayed onto the surface of the sari balls frozen in the freezing process to freeze them.

Description

[Technical field]

[0001] The present invention relates to a method for producing frozen foods, and more particularly to a method for producing frozen foods comprising rice. [Background technology]

[0002] Conventionally, as described in Patent Documents 1 and 2, methods have been proposed for producing frozen foods containing rice by mixing antifreeze protein into rice during cooking, cooking the rice, and freezing it.

[0003] In Patent Document 1 (see paragraph 0043, Table 4, etc.), rice is cooked with antifreeze protein derived from crustaceans, and after cooking, it is molded into a 20 gram sushi mold, frozen at -20°C for 3 days, transferred to -10°C and frozen for 5 days.

[0004] In the examples of Patent Document 2 (see paragraphs 0032, 0037, etc.), rice is cooked after mixing with an antifreeze protein made from radish sprouts, and the cooked rice is divided into 100g portions and stored in a refrigerator-freezer at -20°C. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2007 / 105734 [Patent Document 2] International Publication No. 2010 / 134489 Summary of the Invention [Problem to be solved by the invention]

[0006] Although both Patent Documents 1 and 2 describe a method of mixing antifreeze proteins, cooking rice, and freezing it, they do not describe a freezing method suitable for solidifying rice that has been mixed with antifreeze proteins and cooked into a sari ball shape and freezing it.

[0007] Therefore, an object of the present invention is to provide a method for producing a frozen food suitable for freezing rice that has been mixed with an antifreeze protein and then cooked. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention has the following features. The present invention provides a method for producing frozen foods, characterized by comprising a rice cooking step of cooking rice using water containing added antifreeze protein, a freezing step of freezing the rice obtained in the rice cooking step, and a glazing step of spraying a mist of liquid onto at least a portion of the surface of the rice frozen in the freezing step to freeze it.

[0009] Preferably, the method further comprises a molding step of molding the rice cooked in the rice cooking step into a predetermined shape, the rice molded in the molding step is frozen in the freezing step, and the molded and frozen rice is frozen by spraying a mist of liquid onto at least a portion of the surface thereof in the glazing step.

[0010] Preferably, in the freezing step, the rice is frozen by applying cold air to the rice and vibrating the rice.

[0011] Preferably, the frequency of the vibration applied to the cooked rice in the freezing step is in the range of 25.0 Hz to 35.0 Hz.

[0012] Preferably, the liquid sprayed in the glazing process is purified water.

[0013] Preferably, in the glazing step, the liquid to be sprayed is water to which an antifreeze protein has been added.

[0014] Preferably, in the molding process, the density is 0.5 g / cm 3 ~1.2g / cm 3 It is a good idea to mold the rice to the desired density. More preferably, in the molding process, 0.6 g / cm 3 ~1.0g / cm 3 It is a good idea to mold the rice to the desired density.

[0015] Preferably, the weight of the antifreeze protein added to the water in the rice cooking step is 0.1 to 0.3 (weight %).

[0016] Preferably, the method further includes a soaking step of soaking rice in water to which an antifreeze protein has been added.

[0017] Preferably, the weight of the antifreeze protein added to the water in the water immersion step is 0.1 to 0.3 (wt %). Effect of the Invention

[0018] According to the present invention, a method for producing a frozen food suitable for freezing rice that has been mixed with an antifreeze protein and then cooked using the glaze treatment step is provided.

[0019] The objectives, features, configurations, operations, and effects of the present invention and embodiments of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing a process for producing a rice-containing frozen food (here, frozen sushi) according to one embodiment of the present invention. [Diagram 2] Fig. 2 is a diagram showing the results of a sensory test of an embodiment of the present invention. The appropriate density of cooked rice in Shari-dama is examined using Fig. 2. [Diagram 3] Fig. 3 is a diagram showing the results of a sensory test of an example of the present invention. The effect of the glaze treatment will be considered with reference to Fig. 3. [Figure 4] FIG. 4 is a diagram showing the calculation results of the size and volume of the mold used in the sensory test of one embodiment of the present invention. [Diagram 5] FIG. 5 is a photograph of the frozen Shari-ball used in the sensory test of one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A method for producing a frozen food (frozen sushi) according to one embodiment of the present invention will be described with reference to FIG. First, a liquid in which an antifreeze protein is added to water (hereinafter referred to as an "antifreeze protein-added liquid") is produced (step S101). The antifreeze protein used is preferably one made from radish sprouts, but is not limited thereto. In addition, antifreeze proteins made from fish as raw materials may be used, or antifreeze proteins made from other raw materials may be used.

[0022] The ratio of the antifreeze protein to the water solvent is preferably 0.1 to 0.3% (weight %). For example, a solution is prepared by dissolving 15 g of the antifreeze protein in 8 kg of water. In this case, the ratio of the antifreeze protein to the water is 0.185%. In the examples shown in Figs. 2 and 3 described below, a liquid containing 0.2% antifreeze protein was used.

[0023] In step S102, raw rice is immersed in the antifreeze protein-added liquid. For example, 7 kg of raw rice is immersed in the antifreeze protein-added liquid. The raw rice is preferably, but not limited to, pre-washed rice. If pre-washed rice is not used, the raw rice is washed once and thoroughly drained, and then immersed in the antifreeze protein-added liquid. In addition, since the antifreeze protein-added liquid for immersion is discarded in step S103, the volume thereof is not limited in the present invention.

[0024] In step S103, the antifreeze protein-added liquid is discarded, and the water from the raw rice is thoroughly drained.

[0025] In step S104, the soaked raw rice is cooked in the antifreeze protein-added liquid. The volume of the antifreeze protein-added liquid required for cooking is the same as that for cooking normal sushi rice, but is determined appropriately taking into account the season, the type of raw rice, etc. At this time, it is advisable to add an appropriate amount of rice cooking oil to make the cooked rice easier to handle, but this is not limited thereto.

[0026] After the rice is cooked, in step S105, the rice is mixed with vinegar to produce sushi rice. If the recipe does not require mixing in vinegar, step S105 is omitted.

[0027] Then, the sushi rice is shaped into individual sushi balls, and toppings are placed on them as appropriate (step S106). Any known method can be used to shape the sushi balls. Any known conditions can be used to apply pressure to the sushi balls. The sushi balls and toppings can be appropriately held by a person or a robot. The sushi to be produced is not limited to nigiri sushi, and can be any type of sushi, such as rolled sushi, temari sushi, or pressed sushi.

[0028] The sushi made in step S106 is frozen (S107). Any known freezing method may be used, but for example, the sushi may be quickly frozen by applying cold air to it in a tunnel freezer (registered trademark) and vibrating it.

[0029] The conditions for the Tunnel Freezer (registered trademark) were a set temperature of -40°C, a transit time of 28 minutes, and a vibration frequency of 30.0 Hz. Of course, these setting conditions are merely an example, and the setting conditions for a tunnel freezer (registered trademark) may be a set temperature of -35°C to -45°C, a transit time of 25 to 31 minutes, and a vibration frequency in the range of 25.0 Hz to 35.0 Hz. More preferably, the conditions for setting the tunnel freezer (registered trademark) are a set temperature of -35°C to -40°C, a transit time of 25 to 28 minutes, and a vibration frequency in the range of 30.0 Hz to 35.0 Hz.

[0030] The sushi frozen in step S107 is subjected to a glaze treatment using a liquid containing antifreeze protein (S108). Glazing is the process of forming a thin layer of ice on the surface of a frozen food. Spray the frozen sushi with antifreeze protein-added liquid and freeze it. This will create a thin layer of ice on the surface of the sushi, and if necessary, repeat this process several times to achieve the right thickness of glaze.

[0031] Finally, the frozen sushi made in step S108 is packed into packages, an oxygen absorber is injected, and the package is vacuum-packed while replacing the gas, completing the individually packaged frozen sushi (step S109). In addition, multiple frozen sushi may be packed together in a plastic container or other package and vacuum-packed while replacing the gas. As a packing method, any known method can be used. For example, the components may be vacuum-packaged individually or in a container without using gas exchange.

[0032] After the sari ball is glazed, the sushi toppings may be placed on the sari ball and then frozen.

[0033] By defrosting the frozen sushi produced in the manner described above in the refrigerator compartment of a typical household refrigerator (at around 10 degrees) for 3 to 5 hours, the sushi rice will be defrosted without turning white wax, making it delicious to eat. EXAMPLES

[0034] Antifreeze protein is dissolved in boiled water to produce antifreeze protein-added liquid. Here, Kaneka Foods Corporation's product name "Kaneka Antifreeze Protein KR1" and "Radish sprouts extract (food additive)" are used as the antifreeze protein. The concentration of the antifreeze protein-added liquid is 0.2% of the antifreeze protein relative to the water.

[0035] To manufacture the Shari-dama, a mold with the dimensions shown in Figure 4 was used. As shown in Figure 4, the volume of the mold was approximately 22.44 cm. 3 It is. Sample 1 was made by putting 15 grams of cooked rice into the mold. To calculate the density of the cooked rice, the weight of the cooked rice divided by the volume of the mold was calculated as shown in Figure 4. Sample 1 had a density of 0.67 g / cm 3 It became. Sample 2 was made by putting 18 grams of cooked rice into the mold. Sample 2 had a thickness of 0.80 g / cm 3 It became. Sample 3 was made by putting 25 grams of cooked rice into the mold. Sample 3 had a density of 1.12 g / cm 3 It became.

[0036] In FIG. 2, samples labeled 15g, 18g, and 25g correspond to the above samples 1 to 3, respectively. In addition, in FIG. 2, for samples 1 to 3, the presence or absence of antifreeze protein and the cooking methods A, B, C, and D were used as variations in the cooking method.

[0037] A was cooked using an antifreeze protein-added liquid containing 0.2% antifreeze protein relative to the weight of the water, without soaking. B was soaked overnight in an antifreeze protein-added liquid containing 0.2% antifreeze protein relative to the weight of the water, and then cooked in the antifreeze protein-added liquid. C was cooked in tap water without using antifreeze protein or soaking. D was soaked in tap water overnight without using antifreeze protein and then cooked in tap water. The tap water used was from 4-16 Shikinaicho, Izumiotsu City, Osaka Prefecture.

[0038] The cooked rice was pressed into balls using the above-mentioned mold, frozen, and stored for at least 48 hours. Sensory tests were then conducted on the balls after thawing in a 10°C defroster for 1, 2, and 3 hours. The sensory tests were carried out to check the degree of thawing and white waxiness. The degree of thawing was evaluated as follows: (1) to (5). Note that (1) refers to the number 1 in a circle in Figure 1 (and so on).

[0039] (Evaluation of thawing condition) (1) It's not solved. It's all hard. (2) The outside is molten and the center is hard. (3) It has thawed but is still hard and inedible. (4) Thawed but still cold and edible. (5) It is soluble and edible.

[0040] The evaluation of white waxiness is as follows: (1) to (5). (1) Hard and completely devoid of moisture. (2) It is hard and has no moisture in the center. It has a core. (3) It is not hard. There is a little moisture remaining in the center. You can feel the core. (4) It is soft. There is moisture in the center. You cannot feel the core. (5) Soft - there is moisture in the center. There is no core and it is delicious.

[0041] As shown in Figure 2, two hours after the start of thawing, the 15g, 18g, and 25g samples were insufficiently thawed regardless of cooking method A to D. Three hours after the start of thawing, the 15g and 18g samples were completely thawed and rated edible (5) in the cases of cooking methods A and B (areas circled in the upper part of Figure 2). Furthermore, for the evaluation of white waxiness, 3 hours after the start of thawing, the 15 g and 18 g samples were rated as (4) when cooked using methods A and B (the area circled in the upper part of Figure 2). As shown in Figure 2, cooking methods A and B were rated the same for both the degree of thawing and white waxiness, but the taste of the rice cooked using method B, in which the rice was soaked overnight, was more delicious.

[0042] For the 25g samples cooked using methods A and B, the degree of thawing was evaluated as (4) three hours after the start of thawing. Therefore, it can be inferred that the thawing of the 25g samples would progress if the thawing time was extended a little more. For the 25g samples cooked using methods A and B, the evaluation of white waxiness was (3) three hours after the start of thawing.

[0043] From the experiment in Figure 2, it was found that samples 1 and 2 with densities of 15g and 18g were suitable for eating deliciously after thawing in about 3 hours. The density of sample 1 was 0.67g / cm 3 and the density of sample 2 is 0.80 g / cm 3 The density of 25 g of sample 3 was 1.12 g / cm 3 However, it is possible to eat it if the thawing time is extended.

[0044] Therefore, although the present invention is not limited to the density, it is preferably 0.80 g / cm 3 For example, the density of rice, expressed as the weight of rice relative to the volume of the mold, is 0.5 g / cm 3 ~1.2g / cm 3 Preferably, it is 0.6 g / cm 3 ~1.0g / cm 3 It would be good if that were the case.

[0045] The experiment in Fig. 2 was conducted to determine the standard density of the relic ball. The feature of the present invention is to apply a glaze treatment to the relic ball, so the density of the relic ball does not limit the present invention.

[0046] Next, the results of the sensory test with and without glaze treatment will be described with reference to Fig. 3. In Fig. 3, the 18g sample sari ball used in the experiment in Fig. 2 was used. The rice used for the sari ball was soaked overnight in an antifreeze protein-added liquid containing 0.2% antifreeze protein relative to the weight of the water, and then cooked in the antifreeze protein-added liquid. No mixed vinegar or topping was used in the sample.

[0047] The rice cooked in this way was formed into sari balls and frozen (S107 in Figure 1). In sample a, the sarira ball was glazed using a liquid containing 0.2% antifreeze protein (S108 in Figure 1). For sample b, the sarira was glazed using purified tap water from a filter-type water purifier (S108 in Figure 1). Sample c is the sarira ball that was frozen in S107 of FIG. 1 and was not glazed.

[0048] In samples a and b, a mist of liquid is sprayed from above the relic ball, so no liquid adheres to the bottom of the relic ball.

[0049] In Figure 3, the completed samples were stored for 48 hours or more, and then thawed for 1 to 8 hours in a thawing chamber at 10°C, and then subjected to a sensory test. The evaluation of the thawing condition and white waxiness in the sensory test in Figure 3 was the same as in Figure 2.

[0050] Three hours after the start of thawing, samples a, b, and c are ready to eat. Even after 4 and 5 hours had passed since the start of thawing, samples a and b, which are examples, were rated as (5) in terms of white wax formation. On the other hand, for sample c, which is a comparative example, the evaluation of white wax formation remains at (4) even after 3 hours, 4 hours, and 5 hours have passed since the start of thawing.

[0051] The sensory test in Figure 3 shows that by freezing the Shari balls and then glazing them with a liquid containing antifreeze protein or with water without it, it is possible to prevent the balls from turning white and maintain them in a delicious edible state for 3 to 5 hours after thawing begins. Sample c, which was not glazed, was soft with moisture remaining in the center and no core was felt, but it was inferior to the glazed sample in terms of palatability.

[0052] Furthermore, after 6 hours from the start of thawing, the samples gradually dried out and turned white and waxy, and the flavor of all three samples a, b, and c deteriorated.

[0053] The liquid used for the glaze treatment may be a liquid containing antifreeze protein, purified water, or tap water.

[0054] In this way, in the present invention, by cooking rice using the liquid containing antifreeze protein, it is possible to prevent the rice from turning white even after thawing. In addition, by applying a glaze treatment to the rice ball, it is possible to prevent the rice ball from drying out or turning white even after thawing. It is presumed that the liquid film around the rice ball caused by the glaze treatment is absorbed by the rice, allowing the rice ball to maintain a proper moisture state for a long time, making it possible to eat it deliciously.

[0055] In the above embodiment and example, the rice is molded into a sari ball, but the shape of the mold is not limited to a sari ball. If the rice is molded into a certain shape or placed in a certain container, and then the rice is frozen, and then a liquid mist is sprayed onto the surface of the frozen rice to perform a glaze treatment, the rice can be kept in a state of properly retaining moisture for a long time after thawing, and can be eaten deliciously.

[0056] Therefore, the present invention is characterized in that rice cooked in an antifreeze protein-added liquid is frozen, and then a glaze treatment is carried out by spraying a mist of liquid onto the surface of the frozen rice to freeze it. The liquid to be sprayed may be water (water containing no additives) or water to which an antifreeze protein has been added (antifreeze protein-added liquid). In addition, an additive suitable for the glaze treatment may be added to the liquid to be sprayed.

[0057] In addition, there may be some places where the mist liquid cannot be sprayed, such as the bottom of the frozen rice or the bottom of the rice. In other words, the glaze treatment may be applied to at least a part of the surface of the frozen rice. Also, the frozen rice or the mist may be lifted up and the bottom may be sprayed with the mist liquid to apply the glaze treatment to the entire surface.

[0058] Although the present invention has been described in detail above, the above description is merely illustrative of the present invention in every respect and is not intended to limit its scope. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. The constituent elements of the invention disclosed in this specification are each considered to be independent and stand alone as a single invention. Inventions in which the constituent elements are combined in any combination method are also included in the present invention. The specific expressions in this specification are merely illustrative, and the present invention also includes those that conceptualize the illustrative expressions. [Industrial Applicability]

[0059] The present invention relates to frozen foods and is industrially applicable.

Claims

1. A rice cooking process in which rice is cooked using water to which an antifreeze protein has been added; A freezing step of freezing the rice obtained in the rice cooking step; and a glaze treatment step of spraying a mist of liquid onto at least a portion of the surface of the rice frozen in the freezing step to freeze the rice.

2. The method further includes a forming step of forming the rice cooked in the rice cooking step into a predetermined shape, In the freezing step, the rice molded in the molding step is frozen, 2. The method for producing a frozen food according to claim 1, wherein in the glazing step, a mist of liquid is sprayed onto at least a portion of the surface of the molded and frozen rice to freeze it.

3. 2. The method for producing a frozen food according to claim 1, wherein in the freezing step, the rice is frozen by vibrating the rice while applying cold air to the rice.

4. 4. The method for producing a frozen food according to claim 3, wherein the frequency of the vibration applied to the rice in the freezing step is in the range of 25.0 Hz to 35.0 Hz.

5. In the glaze treatment process, the liquid to be sprayed is purified water. A method for producing the frozen food according to claim 1.

6. 2. The method for producing a frozen food according to claim 1, wherein the liquid sprayed in the glaze treatment step is water to which an antifreeze protein has been added.

7. In the molding process, 0.5 g / cm 3 ~1.2g / cm 3 3. The method for producing a frozen food according to claim 2, wherein the rice is molded to a density of 1000 g / g.

8. In the molding process, 0.6 g / cm 3 ~1.0g / cm 3 8. The method for producing a frozen food according to claim 7, wherein the rice is molded to a density of 1000 g / g.

9. 2. The method for producing a frozen food according to claim 1, wherein the weight of the antifreeze protein added to the water in the rice cooking step is 0.1 to 0.3 (wt%).

10. 2. The method for producing a frozen food according to claim 1, further comprising a soaking step of soaking rice in the water to which the antifreeze protein has been added.

11. The method for producing a frozen food according to claim 10, wherein the weight of the antifreeze protein added to the water in the immersion step is 0.1 to 0.3 (wt %).

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