Method for producing frozen stuffed food

Abstract

To provide a simple and low-cost method for producing a frozen filled bean jam food suppressed in hardening of a skin and hardening of palate feeling when heated and thawed, compared with a heat-cooked filled bean jam food before frozen, and suppressed in influence on taste of the filled bean jam food.SOLUTION: The method for producing the frozen filled food product includes forming an ice film on the surfaces of the frozen and cooked filled food product (process S03).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a frozen filled food product. [Background technology]

[0002] In recent years, frozen foods that can be eaten simply by heating and thawing have become widespread. For example, cooked, frozen, filled foods have been put on the market, which are prepared by freezing a cooked, filled food. Consumers can eat the cooked, filled food simply by heating and thawing it at home using a microwave oven or the like.

[0003] However, foods prepared by heating and thawing frozen filled foods with bean paste by microwaves such as a microwave oven often have an inferior texture compared to the unfrozen filled foods. Specifically, the skin encasing the bean paste filling may become hard, resulting in a hard texture.

[0004] Various studies have been conducted to improve the quality of frozen foods, and in response to the above-mentioned problems, for example, Patent Document 1 (JP 2023-131007 A) proposes a method of adhering a composition containing (a) water, (b) fats and oils, and (c) sugars, and at least one selected from the group consisting of amino acids and their salts, to substantially the entire surface of an enclosed food product, baking the enclosed food product to which the composition has been attached, and freezing the baked and heated enclosed food product. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-131007 Summary of the Invention [Problem to be solved by the invention]

[0006] It is described in Patent Document 1 that frozen filled foods obtained by the method are prevented from whitening at the overlapping portions of the outer skins after thawing, even when heated and thawed using microwaves such as a microwave oven, and that the texture of the overlapping portions of the outer skins is prevented from becoming hard (Patent Document 1: Paragraph

[0010] ). On the other hand, the method of Patent Document 1 applies a composition containing sugar or amino acids to substantially the entire surface of the filled food, which can easily affect the taste of the filled food. Furthermore, the setting and management of the specific blending ratios of water, oil, and sugar or amino acid, as well as the equipment required, can be relatively complicated and expensive. [Means for solving the problem]

[0007] The present invention has been made in view of the above circumstances, and aims to provide a simple, low-cost method for producing a frozen filled food product in which, when heated and thawed, the skin is prevented from becoming hard and the texture is prevented from becoming hard, compared with a cooked filled food product before freezing, and which can minimize the effect on the taste of the filled food product.

[0008] The present invention solves the above problems by the solution means described below as one embodiment.

[0009] The method for producing a frozen filled food product according to the present invention is characterized by forming an ice film on the surface of a frozen, cooked filled food product. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a frozen bean paste filled food product that can suppress the influence on the taste of the bean paste filled food product and that, when thawed by heating, does not have a hardened skin and texture compared to a cooked bean paste filled food product before freezing, by a simple and low-cost method. [Brief explanation of the drawings]

[0011] [Figure 1]Figure 1A is a photograph of a frozen, cooked, stuffed food (gyoza) before an ice film forms on its surface. Figure 1B is a photograph of the frozen, cooked, stuffed food (gyoza) shown in Figure 1A after an ice film has formed on its surface. [Figure 2] FIG. 2 is a flowchart showing an example of a method for producing a frozen filled food product according to this embodiment. [Figure 3] Fig. 3A is a photograph of a conventional frozen encased food (shumai) without an ice layer after being heated and thawed using microwaves. Fig. 3B is a photograph of a frozen encased food (shumai) according to the present embodiment with an ice layer after being heated and thawed using microwaves. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the present invention, the "cooked frozen encased food" refers to a frozen food obtained by freezing a cooked encased food, and is a food to be eaten by heating and thawing. In this specification, the "cooked frozen encased food" may be simply referred to as the "frozen encased food."

[0013] In the present invention, the term "filled food" refers to a food that includes a filling and a skin that encases at least a portion of the filling. The number of skins and the covering form (enveloping method) are not limited. Examples of filled foods include shumai, gyoza, xiaolongbao, baozi, Chinese buns, wontons, and spring rolls.

[0014] In the present invention, the term "cooked filled food" refers to a filled food that has been subjected to at least a heat treatment as a cooking step, such as a filled food in which dough enveloping ingredients is heated in order to gelatinize the starch that is the raw material of the dough. The manner of heat treatment is not limited, and the filled food may be one or more types of heat treatment such as steaming, boiling, baking, frying, or oven heating, which may be performed at least once.

[0015] The "heat thawing" performed on the frozen encased food of the present invention when it is eaten is a heat treatment for at least thawing the frozen encased food. The manner of the heat treatment is not limited, and the frozen encased food can be thawed and eaten by heating with microwaves using a microwave oven or the like, or by heating with infrared rays using an oven or the like.

[0016] The manufacturing method of the present invention is particularly suitable when applied to frozen filled foods prepared by freezing steamed and cooked filled foods such as shumai, xiaolongbao, baozi, and Chinese buns, and further to the widely used frozen filled foods for thawing by microwave heating, because the hardening of the skin and texture is suppressed compared to steamed and cooked filled foods before freezing, and the finished product has a plump, freshly steamed appearance and texture that is likely to be improved compared to conventional products.

[0017] The present invention relates to a method for producing a frozen encased food, characterized by forming an ice film on the surface of a frozen, cooked, encased food. The inventors measured the weight of frozen encased foods before and after thawing using a microwave oven and confirmed that the weight decreased after thawing. This suggests that the main reason why the skin of a frozen encased food becomes hard and its texture becomes tough when thawed is due to the evaporation and loss of moisture from the skin. The inventors then produced a prototype frozen encased food by applying water to the surface of the cooked encased food and then freezing it. However, when thawed, the skin became excessively moist, becoming sticky and unpleasant to eat. After much trial and error, the inventors arrived at the invention of forming an ice film on the surface of a frozen, cooked, encased food.

[0018] In the present invention, by protecting the surface of a frozen encased food with an ice film, when the frozen encased food is heated and thawed, the water forming the ice film on the surface of the frozen encased food evaporates and disappears, while the moisture in the skin remains. Therefore, the skin is prevented from becoming hard and the texture is prevented from becoming hard. It has been confirmed that the weight loss after heating and thawing is almost the same between frozen encased foods with an ice film and frozen encased foods without an ice film. Therefore, by adjusting the amount of water forming the ice film according to the heating and thawing conditions set based on the amount of water lost from frozen encased foods without an ice film, the amount of water remaining in the skin can be easily adjusted, and the texture of a cooked encased food can be reproduced.

[0019] The ice film can be easily formed by adhering water to the surface of the frozen, cooked, enclosed food. The water adhering to the surface of the frozen, cooked, enclosed food converts into ice using the cold heat absorbed from the frozen, enclosed food as latent heat. As a result, an ice film is formed on the surface of the frozen, cooked, enclosed food.

[0020] Figure 1A is a photograph of a frozen, cooked, stuffed food (gyoza) before an ice film forms on its surface. Figure 1B is a photograph of the frozen, cooked, stuffed food (gyoza) shown in Figure 1A after a certain time has passed since water was sprayed onto the surface using a household spray bottle. An ice film has formed on the surface of the frozen stuffed food (gyoza) in Figure 1B.

[0021] In this manner, the method of adhering moisture to the surface of the frozen, cooked, encased food in a filling is, in this embodiment, a method of spraying water onto the surface of the frozen, cooked, encased food, but is not limited to this, and other methods may also be used, such as immersing the frozen, cooked, encased food in a tank containing water. The water spraying method according to this embodiment has the advantage of easily adjusting the amount of moisture to be adhered to the surface of the frozen, cooked, encased food.

[0022] The water used to form the ice film can be any drinkable water suitable for food production, without particular limitations. For example, purified water such as distilled water or ion-exchanged water, or tap water, can be used, sterilized as necessary. Thus, the present invention solves the problem with a simple, low-cost method by depositing only water on the surface of a frozen food, which essentially disappears upon thawing. This minimizes the impact on the taste of the filled food. However, other ingredients may be mixed, dispersed, or dissolved in the water, provided that the ice film formation is not impaired. Adding other ingredients to the water can also intentionally affect the taste of the filled food. Examples of ingredients that can be added to the water include salt, spices, seasonings, colorings, flavorings, and preservatives. Therefore, the method of the present invention, which minimizes the impact on the taste of the filled food, can be said to allow for a certain degree of adjustment of the taste and / or flavor of the filled food. In other words, in the present invention, the water used to form the ice film can also be an aqueous solution, an aqueous dispersion, or the like.

[0023] The temperature of the water used to form the ice film is preferably as close to the freezing point as possible, since this is thought to prevent the surface temperature of the frozen filled food from rising when the water is applied to the surface of the frozen filled food and allow the ice film to form more quickly. Therefore, the temperature of the water is preferably cold water, for example, 10°C or less, and ice water, for example, can be used.

[0024] Furthermore, it is preferable to set the temperature of the water applied to the surface of a frozen, cooked, filled food product below 6°C. The present inventors have confirmed that when ice water at about 5-6°C is sprayed in mist form over the entire surface of a cooked, filled food product (shumai) that has been frozen to the inside at room temperature, the surface water begins to freeze and an ice film forms after about one minute. Therefore, by setting the temperature of the water applied to the surface of a frozen, cooked, filled food product below 6°C, an ice film can be formed over the entire surface of the frozen, cooked, filled food product, even if the ice film formation process (from the time the water is applied until the formation of the ice film is completed) is set to a maximum of 10 minutes, which is a setting expected for practical implementation.

[0025] More preferably, the temperature of the water applied to the surface of the frozen, cooked, filled food is set to be lower than 5°C, and even more preferably lower than 3°C.

[0026] Furthermore, it is preferable to set the surface temperature of the frozen, cooked, encased food below -10°C. The inventors have confirmed that when ice water at approximately 5-6°C is sprayed in a mist form at room temperature onto the entire surface of a cooked, encased food (shumai) that is frozen to the inside and has a surface temperature of -10°C or higher, the surface temperature of the frozen, encased food (shumai) rises over time and reaches the positive temperature range (0°C or lower) after approximately 10 minutes. If the surface temperature of the frozen, encased food reaches the positive temperature range, the surface may begin to thaw, potentially resulting in quality problems. Therefore, by setting the surface temperature of the frozen, cooked, encased food below -10°C before the water is applied, an ice film can be formed with little adverse effect on the quality of the frozen, encased food, even if the ice film formation process (from the time the water is applied until the formation of the ice film) is set to a maximum of 10 minutes, as is assumed in practical implementation.

[0027] More preferably, the surface temperature of the frozen, cooked, filled food is set to -11°C or below (e.g., -11 to -12°C), even more preferably to -12°C or below (e.g., -12 to -13°C), and even more preferably to -13°C or below (e.g., -13 to -15°C).

[0028] The surface temperature of the frozen filled food can be measured using a radiation thermometer suitable for food. Since frozen filled foods are usually mass-produced at the same time, the surface temperature can be calculated, for example, as the average value of multiple individuals in a target area, and the surface temperature of each individual can also be calculated as the average value of multiple measurements. In this way, the surface temperature is not biased depending on the measurement method.

[0029] Specific steps of the method for producing a frozen filled food product according to this embodiment are shown in the flowchart of FIG. 2. First, step S01 of cooking the filled food product is carried out. In step S01, a series of cooking steps involving cooking heat is performed to convert the raw food into a hygienically edible, cooked filled food product. For cooking, ingredients and additives that can be used in filled foods can be used without particular restrictions, and ordinary cooking methods applicable to filled foods can be used. Next, step S02 of freezing the cooked filled food product is carried out. The freezing method and freezing conditions (e.g., freezing temperature, freezing time, etc.) are not limited, and the food can be frozen using known or equivalent methods and conditions. Next, step S03 of forming an ice film on the surface of the frozen, cooked filled food product is carried out. The details of step S03 of forming the ice film have already been described. After step S03, the frozen filled food product according to this embodiment is obtained. In each step or before and after each step, sterilization treatment may be carried out by a known method or under conditions conforming to food hygiene standards as necessary, except that no sterilization treatment that may melt the ice film is carried out after step S03.

[0030] The method for producing a frozen bean-filled food according to this embodiment differs from conventional methods for producing frozen bean-filled foods by freezing a cooked bean-filled food. This method involves freezing the cooked bean-filled food and then applying water to the surface of the frozen bean-filled food. This method is simple and inexpensive, and even when the frozen bean-filled food is thawed by heating, the skin and texture are prevented from becoming hard, compared to the cooked bean-filled food before freezing. In particular, when a frozen bean-filled food is produced by freezing a steamed bean-filled food such as shumai, xiaolongbao, baozi, or Chinese bun, the skin and texture are prevented from becoming hard when the frozen bean-filled food is thawed by heating using microwaves in a microwave oven or the like, and the finished product has a plump, freshly steamed texture, which favorably improves the appearance and texture compared to conventional products (see Examples).

[0031] Figure 3A is a photograph of a conventional frozen stuffed food (shumai) that was not subjected to step S03, i.e., that did not have an ice film formed, after being heated and thawed in a microwave. Figure 3B is a photograph of a frozen stuffed food (shumai) according to the present embodiment, in which an ice film was formed, after being heated and thawed in a microwave. Compared to the stuffed food of Figure 3A, the stuffed food of Figure 3B had a plump, freshly steamed finish, a relatively soft skin texture, and a relatively soft skin texture with a good mouthfeel. [Example]

[0032] [Test 1] The dough was kneaded with wheat flour, salt, and water in a predetermined ratio, rolled out to a predetermined thickness, and cut into squares to make the shumai wrappers. The filling was also made by kneading minced meat, finely chopped onion, seasonings, etc. in a predetermined ratio.

[0033] A single skin was used to completely cover the specified amount of filling, producing cylindrical raw shumai as shown in Figure 3. The raw shumai were steamed to produce cooked shumai, which were then cooled and then flash-frozen for one hour to freeze them to the inside. Hereinafter, cooked shumai (steamed cooked shumai) may be referred to as "steamed shumai," and frozen cooked shumai may be referred to as "frozen shumai."

[0034] The 60 frozen shumai (average weight: 31.24 g) produced were divided into two groups of 30: a treatment group and a control group. The average weight [a] of the frozen shumai in the treatment group (Example 1-30) was 31.21 g, and the average weight [a'] of the frozen shumai in the control group (Comparative Example 1-30) was 31.26 g.

[0035] For the frozen shumai in the treatment group (Example 1-30), the entire surface of each individual piece was sprayed with a mist of ice water at approximately 5-6°C using a household spray bottle at room temperature at least twice. After the water had adhered, it was confirmed that the water began to freeze and an ice film had formed. The weight [b] of the frozen shumai after the ice film had formed was measured, and the weight [a] of the frozen shumai before the ice film had formed (before the water had been applied) was subtracted from this value to calculate the amount of water adhering to the surface of the frozen shumai (adhered water amount [d] = [b] - [a]) for each individual piece and on average. Meanwhile, the frozen shumai in the control group (Comparative Example 1-30) were not subjected to any treatment, including the formation of an ice film.

[0036] The frozen shumai from the treatment group (Example 1-30) and the frozen shumai from the control group (Comparative Example 1-30) were heated and thawed using a household microwave oven. For each group, four shumai were wrapped in microwave-safe wrapping wrap, and the remaining two shumai were wrapped in pairs. They were then heated and thawed in a 600W microwave oven for 2 minutes 50 seconds to 3 minutes. The weights of the shumai from both groups after heating and thawing were then measured [c] and [c']. For the frozen shumai from the treatment group, the weight [c] of the shumai after heating and thawing was subtracted from the weight [b] of the frozen shumai after the ice layer had formed, and the amount of water lost by heating and thawing (water loss [e] = [b] - [c]) was calculated for each individual and averaged. For the control group, the weight of the shumai after heat thawing [c'] was subtracted from the weight of the frozen shumai [a'], and the amount of water lost by heat thawing (amount of water lost [e'] = [a'] - [c']) was calculated for each individual and average. Table 1 shows the results for Example 1-30 in the treatment group. Table 2 shows the results for Comparative Example 1-30 in the control group.

[0037] [Table 1]

[0038] [Table 2]

[0039] As shown in Tables 1 and 2, when comparing the amount of water lost [e] and [e'] by heat-thawing the frozen shumai in both groups, the average for Example 1-30, in which an ice film was formed, was 0.78 g ([e]), while the average for Comparative Example 1-30, in which an ice film was not formed, was 0.86 g ([e']), showing almost no difference. This shows that the amount of water lost by heat-thawing is almost the same whether or not an ice film is formed.

[0040] Furthermore, as shown in Table 1, in Example 1-30, the average weight of the shumai after heat thawing was 31.25 g ([c]), and as a result of heat thawing, the average weight of the frozen shumai before the ice film was formed, 31.21 g ([a]), was almost restored. From another perspective, in Example 1-30, the average amount of water lost from the frozen shumai after heat thawing was 0.78 g ([e]), and as a result of heat thawing, the average amount of water attached to the surface of the frozen shumai, 0.81 g ([d]), was almost completely lost. From this, it can be seen that in the frozen shumai of Example 1-30, on which the ice film was formed, the moisture contained in the frozen shumai (skin) covered with the ice film was able to remain almost intact even after heat thawing.

[0041] Comparing the appearance, texture, and mouthfeel of the shumai after heating and thawing between the two groups, the shumai from the treatment group (Example 1-30) had a plump, freshly steamed finish overall, with a relatively soft skin texture and a relatively soft mouthfeel. On the other hand, the shumai from the control group (Comparative Example 1-30) had a plump appearance overall, although inferior to the treatment group, but the skin texture was relatively hard and the mouthfeel was also relatively hard, resulting in a poor mouthfeel.

[0042] [Test 2] As in Test 1, cylindrical raw shumai were prepared, steamed to make steamed shumai, and then frozen to make frozen shumai. These were then divided into two groups of 15 individuals each: a treatment group and a control group.

[0043] For the frozen shumai in the treatment group, the entire surface of each individual was sprayed with a mist of ice water at about 5-6°C using a household spray bottle at room temperature at least twice, and after the water had adhered to the surface, it was confirmed that the water had begun to freeze and an ice film had formed.On the other hand, the frozen shumai in the control group had not been treated in any way to form an ice film or otherwise.

[0044] The frozen shumai from the treatment area and the control area were thawed using a household microwave oven. For both areas, four pieces were wrapped in microwave-safe wrapping wrap, and the remaining three pieces were wrapped in microwave-safe wrapping wrap, and thawed for 2 minutes 50 seconds to 3 minutes in a 600W microwave oven.

[0045] A sensory test was conducted on the texture of the shumai from the treatment and control groups by a panel of 15 employees of Daifuku Foods Co., Ltd. Each panel member first tasted the shumai from the control group, which had no ice layer formed, and then tasted the shumai from the treatment group, which had an ice layer formed. They then independently evaluated the texture of the shumai from the treatment group compared to the shumai from the control group using the following five-point scale. The results are shown in Table 3.

[0046] (Texture evaluation criteria) 5: Compared to the control, it feels softer and plumper, like it was freshly steamed. 4: Compared to the control, it does not feel hard and feels soft, although not as soft as freshly steamed. 3: Compared to the control, it feels slightly harder, but also softer. 2: Feels harder compared to the control. 1: Feels very hard compared to the control.

[0047] [Table 3]

[0048] As shown in Table 3, 13 out of 15 panelists rated the ice-coated shumai as having an improved texture compared to the non-coated shumai (ratings of 4 or higher). Of these, 7 panelists rated the texture as being similar to that of freshly steamed shumai before freezing (rating of 5). The other 2 panelists also rated the ice-coated shumai as having the same texture as the non-coated shumai (rating of 3). In Experiment 2, the process for preparing the steamed shumai was identical between the treated and control groups, and it can be assumed that the texture of the steamed shumai before freezing was the same. Therefore, this sensory test also demonstrated that, overall, the formation of an ice-coated shumai on the frozen surface significantly reduced the hardening of the skin and texture compared to the pre-cooked, filled shumai (shumai) before freezing. [Explanation of symbols]

[0049] S01 Cooking process of filled food S02 Freezing cooked and filled foods S03 Ice film formation process

Claims

1. Forming an ice film on the surface of frozen cooked filled foods A method for producing frozen filled food, characterized by:

2. The ice film is formed by applying water to the surface of the frozen, cooked, filled food.

2. The method for producing the frozen filled food according to claim 1,

3. The surface temperature of the frozen cooked food is set to be lower than -10°C.

3. The method for producing the frozen filled food according to claim 2,

4. The temperature of the water applied to the surface of the frozen cooked food is set to be lower than 6°C.

4. The method for producing a frozen filled food product according to claim 2 or 3, characterized by:

5. The above-mentioned cooked filled food is a steamed cooked filled food.

2. The method for producing the frozen filled food according to claim 1,

6. The aforementioned stuffed food is shumai 6. The method for producing the frozen filled food according to claim 5,

7. The above-mentioned frozen packed foods are for thawing by microwave heating. The method according to claim 1 or claim 5, characterized by:

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