Manufacturing methods for frozen foods

Abstract

This invention provides a method for producing frozen food suitable for freezing rice that has been cooked with an antifreeze protein mixed in. [Solution] A method for manufacturing frozen food comprising a rice cooking step (S104) in which rice is cooked using water to which antifreeze protein has been added; a molding step (S106) in which the rice obtained in the rice cooking step is formed into rice balls; a freezing step (S107) in which the rice balls obtained in the molding step are frozen; and a glazing step (S108) in which a mist of liquid is sprayed onto the surface of the rice balls frozen in the freezing step and frozen.

Description

[Technical Field]

[0001] This invention relates to a method for producing frozen foods, and more specifically, to a method for producing frozen foods containing rice. [Background technology]

[0002] Conventionally, as described in Patent Documents 1 and 2, a method has been proposed for producing frozen food containing rice by mixing antifreeze protein with rice during cooking, then cooking and freezing the rice.

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

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

[0005] [Patent Document 1] International release 2007 / 105734 [Patent Document 2] International release 2010 / 134489 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Although both Patent Documents 1 and 2 describe a method of cooking rice with an antifreeze protein mixed in and then freezing it, , cooking The cooked rice, A certain shape The instructions do not specify a suitable freezing method for solidifying and freezing the product.

[0007] Therefore, the present invention , cooking The cooked rice Solidify into a certain shape An object of the present invention is to provide a method for producing a frozen food suitable for freezing the cooked rice.

Means for Solving the Problem

[0008] In order to solve the above problems, the present invention has the following features. The present invention comprises a forming step of shaping rice into a predetermined form, A method for producing food, comprising a freezing step of freezing the rice obtained in the forming step, In the formation process, Rice is placed into a mold of a predetermined shape. Rice has a density of 0.5 g / cm³ , ,

[0010] , , , 3 , , ,

[0012] , , , , A mist of liquid is sprayed onto the surface of the food. ,

[0011] , , , In the processing steps, ,

[0009] , Preferably, the process further includes a processing step of applying liquid to the surface of the food obtained in the forming step and the freezing step, , Furthermore, the following inventions are described in this specification. , The process is characterized by applying pressure to form the shape within a specified range. , , It is recommended to cool the sprayed liquid to form a thin layer of ice on the surface of the food. , ~1.2g / cm 3 The process is characterized by applying pressure to form the shape within a specified range. Preferably, the process further includes a processing step of applying liquid to the surface of the food obtained in the forming step and the freezing step, In the processing steps, A mist of liquid is sprayed onto the surface of the food. It is recommended to cool the sprayed liquid to form a thin layer of ice on the surface of the food. Furthermore, the following inventions are described in this specification. The manufacturing method of the frozen food according to the present invention includes a rice-cooking step of cooking rice using water added with an antifreeze protein, a freezing step of freezing the cooked rice obtained in the rice-cooking step, and a glaze treatment step of spraying a mist-like liquid onto at least a part of the surface of the frozen rice to freeze it.

[0009] Preferably, it further includes a molding step of molding the cooked rice into a predetermined shape in the rice-cooking step. In the freezing step, the molded rice is frozen, and in the glaze treatment step, a mist-like liquid is sprayed onto at least a part of the surface of the molded and frozen rice to freeze it.

[0010] Preferably, in the freezing step, the rice is vibrated while being cooled with cold air to be frozen.

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

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

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

[0014] Preferably, in the molding process, 0.5 g / cm³ 3 ~1.2g / cm 3 It is best to shape the rice to this density. More preferably, in the molding process, 0.6 g / cm³ 3 ~1.0g / cm 3 It is best to shape the rice to this density.

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

[0016] Preferably, the process further includes a soaking step in which water to which antifreeze protein is added is soaked in rice.

[0017] Preferably, in the immersion process, the weight of antifreeze protein added to the water is 0.1 to 0.3 (by weight). [Effects of the Invention]

[0018] According to the present invention , cooking This will provide a method for manufacturing frozen foods that is suitable for freezing cooked rice.

[0019] The purpose, features, structure, operation, and effects of the present invention and its embodiments will become even clearer from the following detailed description in reference to the accompanying drawings. [Brief explanation of the drawing]

[0020] [Figure 1] Figure 1 shows the manufacturing process of a frozen food product containing rice (in this case, frozen sushi) according to one embodiment of the present invention. [Figure 2]Figure 2 shows the results of a sensory test of one embodiment of the present invention. Figure 2 is used to examine the appropriate density of cooked rice in the rice ball. [Figure 3] Figure 3 shows the results of a sensory evaluation of one embodiment of the present invention. The effect of the glazing treatment will be examined using Figure 3. [Figure 4] Figure 4 shows the calculated size and volume of the mold used in the sensory test of one embodiment of the present invention. [Figure 5] Figure 5 is a photograph used as a substitute for a drawing, showing the frozen relish ball used in a sensory test of one embodiment of the present invention. [Modes for carrying out the invention]

[0021] Referring to Figure 1, a method for manufacturing a frozen food product (frozen sushi) according to one embodiment of the present invention will be described. First, a liquid obtained by adding antifreeze protein to water (hereinafter referred to as "antifreeze protein-added liquid") is produced (step S101). While antifreeze protein derived from radish sprouts is preferred, it is not limited to that. Furthermore, antifreeze proteins derived from fish may be used, or antifreeze proteins derived from other materials may be used.

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

[0023] In step S102, raw rice is soaked in a liquid containing antifreeze protein. For example, 7 kg of raw rice is soaked in the liquid containing antifreeze protein. While pre-washed rice is preferred, it is not limited to that type of rice. If pre-washed rice is not used, the raw rice is washed once, the water is thoroughly drained, and then it is soaked in the liquid containing antifreeze protein. Furthermore, since the antifreeze protein-added liquid used for immersion is discarded in step S103, its volume is not limited in this invention.

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

[0025] In step S104, the soaked raw rice is cooked in a liquid containing antifreeze protein. The volume of the liquid containing antifreeze protein required for cooking is the same as when cooking regular sushi rice, but is determined as appropriate, taking into consideration the season, the type of raw rice, etc. At this time, adding cooking oil as needed can make the cooked rice easier to handle, but it is not limited to this method.

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

[0027] Then, the sushi rice is shaped into individual balls, and the toppings are placed on top as appropriate (step S106). Any known method can be used to shape the balls of sushi. Any known pressure can be applied to the balls of sushi. The balls of sushi and the toppings may be shaped by hand or by a robot as appropriate. The sushi produced is not limited to nigiri sushi; it can be any type of sushi, such as maki sushi, temari sushi, or oshi sushi.

[0028] The sushi prepared in step S106 is frozen (S107). Any known freezing method can be used, but for example, it is good to rapidly freeze the sushi by exposing it to cold air and vibrating it in a tunnel freezer (registered trademark).

[0029] The settings for the tunnel freezer (registered trademark) were as follows: set temperature -40 degrees Celsius, pass-through time 28 minutes, and vibration frequency 30.0 Hz. Of course, these settings are just one example. For a tunnel freezer (registered trademark), it is recommended to set the temperature to -35°C to -45°C, the passage time to 25 to 31 minutes, and the vibration frequency to within the range of 25.0Hz to 35.0Hz. More preferably, the setting conditions for the tunnel freezer (registered trademark) should be a set temperature of -35°C to -40°C, a passage time of 25 minutes to 28 minutes, and an oscillation frequency in the range of 30.0 Hz to 35.0 Hz.

[0030] The sushi frozen in step S107 is then glazed using a liquid containing antifreeze protein (S108). Glazing is a process that forms a thin layer of ice on the surface of frozen food. Spray the frozen sushi with an antifreeze protein-added liquid using a spray bottle, then freeze it. This creates a thin layer of ice on the surface of the sushi. Repeat this process several times as needed to create a glaze of the desired thickness.

[0031] Finally, the frozen sushi prepared in step S108 is packed into containers, an oxygen absorber is injected, and the containers are vacuum-sealed while gas is being replaced to complete the individually packaged frozen sushi (step S109). Alternatively, multiple frozen sushi items can be packed together in a plastic container or similar pack at once and then vacuum-sealed while purging the gas. In addition, any known method can be used for packaging. For example, the products may be vacuum-packed individually or in containers without using gas displacement.

[0032] Incidentally, after subjecting the舍利玉 to a glazing process, sushi toppings may be placed on the舍利玉 and then frozen.

[0033] By thawing the frozen sushi produced as described above in the refrigerator compartment (around 10 degrees Celsius) of a general household refrigerator for 3 to 5 hours, the sushi rice can be thawed without becoming white and waxy, and it becomes possible to eat it deliciously.

Example

[0034] Dissolve a freeze - resistant protein in the boiling water to produce a freeze - resistant protein - added liquid. Here, as the freeze - resistant protein, the product name "Kaneka Freeze - Resistant Protein KR1" and the name "Kaiware Daikon Radish Extract (food additive)" of Kaneka Food Co., Ltd. were used. The concentration of the freeze - resistant protein - added liquid was set such that the freeze - resistant protein was 0.2% with respect to water.

[0035] For the production of舍利玉, a pressing mold with the dimensions shown in Figure 4 was used. As shown in Figure 4, the volume of the pressing mold is approximately 22.44 cm 3 It is. As Sample 1,舍利玉 made by putting 15 grams of cooked rice into the above - mentioned pressing mold was used. To obtain the density of the cooked rice at this time, (weight of the cooked rice)÷(volume of the pressing mold) was calculated as shown in Figure 4. Sample 1 was 0.67 g / cm 3 It became. As Sample 2,舍利玉 made by putting 18 grams of cooked rice into the above - mentioned pressing mold was used. Sample 2 was 0.80 g / cm 3 It became. As Sample 3,舍利玉 made by putting 25 grams of cooked rice into the above - mentioned pressing mold was used. Sample 3 was 1.12 g / cm 3 It became.

[0036] In Figure 2, the samples marked 15g, 18g, and 25g correspond to Samples 1 to 3 described above, respectively. Also, in Figure 2, for Samples 1 to 3, cooking methods A, B, C, and D were used as variations in the presence or absence of a freeze - resistant protein and the cooking method.

[0037] A was cooked without soaking, using a liquid containing 0.2% antifreeze protein relative to the weight of the water. B was prepared by soaking it overnight in an antifreeze protein-added liquid containing 0.2% antifreeze protein relative to the weight of water, and then cooking it in the said antifreeze protein-added liquid. C was cooked in tap water without using antifreeze proteins or soaking. D was prepared by soaking the ingredients in tap water overnight without using antifreeze proteins, and then cooking them in tap water. The tap water used was from the tap at 4-16 Shikinai-cho, Izumiotsu City, Osaka Prefecture.

[0038] Cooked rice prepared under the above conditions was shaped into rice balls using the above mold, frozen, stored for 48 hours or more, and then thawed in a 10°C thawing chamber for 1, 2, or 3 hours. A sensory evaluation was then conducted on these samples. The sensory evaluation will focus on the degree of thawing and the appearance of white wax. The evaluation of the thawing process is as follows (1) to (5). Note that (1) refers to the number 1 in the circle in Figure 1 (and so on).

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

[0040] Furthermore, the evaluation of the whitening process is as follows (1) to (5). (1) Hard and generally lacking in moisture. (2) Hard; dry in the center. Has a core. (3) Not hard; some moisture remains in the center. The core can be felt. (4) Soft; moisture remains in the center. No hard core is felt. (5) Soft and moist in the center. No hard core at all, 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 through D. Three hours after the start of thawing, the 15g and 18g samples were completely thawed and rated as edible (5) when using cooking methods A and B (indicated by the circles in Figure 2). Furthermore, regarding the evaluation of the whitening process, three hours after the start of thawing, the 15g and 18g samples received a rating of (4) for cooking methods A and B (indicated by the circle in Figure 2). In Figure 2, both cooking methods A and B received the same evaluation for thawing and whitening, but in terms of taste, cooking method B, which involved soaking overnight, tasted better.

[0042] For the 25g samples cooked using methods A and B, the degree of thawing was rated (4) after 3 hours from the start of thawing. Therefore, it can be inferred that if the thawing time is extended further, the 25g samples will also thaw more. For the 25g samples cooked using methods A and B, the evaluation of whitening was (3) three hours after the start of thawing.

[0043] From the experiment shown in Figure 2, it was found that the densities of samples 15g and 18g, respectively, were suitable for delicious consumption after thawing in approximately 3 hours. The density of sample 1 was 0.67 g / cm³. 3 Therefore, the density of sample 2 is 0.80 g / cm³. 3 The density of sample 3 (25g) was 1.12g / cm³. 3 However, it can be eaten if the thawing time is extended.

[0044] Therefore, regarding density, although this does not limit the present invention, it is preferably 0.80 g / cm³. 3It should be around the same value. For example, the density of rice, expressed as the weight of rice relative to the volume of the mold, is 0.5 g / cm³. 3 ~1.2g / cm 3 It is often, preferably 0.6 g / cm³ 3 ~1.0g / cm 3 It would be good if that were the case.

[0045] The experiment in Figure 2 is an experiment to determine a guideline for the density of the reliquary ball. Since the characteristic of this invention is that the reliquary ball is glazed, the density of the reliquary ball is not limiting to this invention.

[0046] Next, the results of the sensory evaluation with and without glazing will be explained with reference to Figure 3. In Figure 3, the 18g sample rice ball used in the experiment in Figure 2 was used. The rice used for the rice ball was soaked overnight in an antifreeze protein-added liquid containing 0.2% antifreeze protein relative to the weight of water, and then cooked in the same antifreeze protein-added liquid. No seasoned vinegar or toppings were used in the sample.

[0047] The rice cooked in this way was formed into rice balls and frozen (S107 in Figure 1). Then, in sample a, the shallots were glazed using a 0.2% antifreeze protein-containing liquid (S108 in Figure 1). In sample b, tap water purified using a filter-type water purifier was used to glaze the relic beads (S108 in Figure 1). Sample c is the rice ball that was frozen in S107 in Figure 1, without being glazed.

[0048] In samples a and b, a mist of liquid was sprayed from above the reliquary ball, so no liquid adhered to the bottom surface of the reliquary ball.

[0049] In Figure 3, sensory evaluations were conducted on samples that had been stored for more than 48 hours and then thawed in a 10°C thawing chamber for 1 to 8 hours. The evaluation of the degree of thawing and the whitening of wax in the sensory evaluation in Figure 3 was the same as in Figure 2.

[0050] Three hours after the start of thawing, samples a, b, and c were in an edible state. Even after 4 and 5 hours from the start of thawing, samples a and b, which are examples, still received a rating of (5) regarding the whitening of wax. On the other hand, for the comparative example sample c, the evaluation regarding white wax formation remained at (4) even after 3, 4, and 5 hours from the start of thawing.

[0051] The sensory evaluation in Figure 3 shows that by glazing the rice balls with either a liquid containing antifreeze protein or water without the protein after freezing, it was possible to maintain a delicious state for 3 to 5 hours after thawing, while preventing the whitening of the waxy substance. In sample c, which was not glazed, although it was soft with moisture remaining in the center and no hard core was felt, it was found to be inferior to the glazed sample in terms of taste.

[0052] Furthermore, after 6 hours from the start of thawing, drying and whitening gradually progress, and the taste of all samples a, b, and c deteriorates.

[0053] The liquid used for glazing can be an antifreeze protein-added liquid, purified water, or tap water.

[0054] Thus, in this invention, by cooking rice using a liquid containing antifreeze protein, it is possible to prevent the rice from turning white and waxy after thawing. In addition, by applying a glaze to the rice balls, drying and turning white and waxy can be prevented even after thawing. It is presumed that the liquid film around the rice balls due to the glaze treatment is absorbed by the rice, allowing the rice balls to maintain their moisture content appropriately for a longer period, making them delicious to eat.

[0055] In the above embodiments and examples, the rice is molded into rice balls, but the shape is not limited to rice balls. By molding the rice into a predetermined shape or placing it in a predetermined container, freezing the rice, and then spraying a liquid in a mist onto the surface of the frozen rice to apply a glaze, it is possible to similarly maintain an appropriate moisture content for a long time after thawing, making it delicious to eat.

[0056] Therefore, the present invention is characterized by freezing rice cooked with an antifreeze protein-added liquid, and then applying a glazing treatment to the surface of the frozen rice by spraying a mist of liquid onto it. The liquid to be sprayed may be water (water without additives) or water with added antifreeze protein (antifreeze protein-added liquid). In addition, additives suitable for glazing treatment may be added to the liquid to be sprayed.

[0057] It is acceptable that there may be areas where the mist-like liquid cannot be sprayed, such as the bottom of the frozen rice balls or the bottom of the rice. In other words, the glazing only needs to be applied to at least a portion of the surface of the frozen rice. Alternatively, the frozen rice balls or rice may be lifted and the mist-like liquid sprayed onto the bottom as well, ensuring that the entire surface is glazed.

[0058] Although the present invention has been described in detail above, the above description is merely illustrative in all respects and is not intended to limit its scope. Needless to say, various improvements and modifications can be made without departing from the scope of the present invention. Each constituent element of the invention disclosed herein shall stand as an independent and standalone invention. Inventions that combine each constituent element in any way shall also be included in the present invention. The specific expressions in this specification are merely illustrative, and the present invention shall also include conceptualizations of such illustrative expressions. [Industrial applicability]

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

Claims

1. A forming step of shaping rice into a predetermined shape, A method for producing food, comprising a freezing step of freezing rice obtained in the above forming step, In the formation process, Rice is placed into a mold of a predetermined shape. A method for manufacturing frozen food, characterized by molding rice under pressure so that its density is in the range of 0.5 g / cm³ to 1.2 g / cm³.

2. The process further comprises a step of applying liquid to the surface of the food obtained in the forming step and the freezing step, In the aforementioned processing step, A mist of liquid is sprayed onto the surface of the food. A method for producing frozen food according to claim 1, characterized by cooling a sprayed liquid to form a thin layer of ice on the surface of the food.

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