JPH11299463A - Frozen food for microwave oven and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a frozen food for a microwave oven rapidly, uniformly and thermally cookable when heated in the microwave oven and to provide a method for producing the frozen food. SOLUTION: One or more kinds of solutes selected from common salt, sugar, glucose, fructose, a thick malt syrup, an isomerized sugar, a trehalose, glycerol, sorbitol, maltitol, erythritol, ethyl alcohol, etc. are dissolved in an aqueous medium to depress the freezing point. The resultant antifreezing fluid is regulated to <=-5 deg.C freezing point is emulsified into a water-in-oil type with an edible oil and fat or encapsulated with a film material. The resultant emulsion or capsule is then formulated to produce a frozen food for a microwave oven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frozen food for a microwave oven containing an antifreeze solution in which a solute is dissolved in an aqueous medium to lower the freezing point, and a method for producing the frozen food. The frozen food for a microwave oven according to the present invention is heated quickly and uniformly in a microwave oven in a short time.

[0002]

2. Description of the Related Art Conventionally, various types of frozen foods placed in individual food containers and heated in a microwave oven at the time of ingestion are commercially available. However, when these frozen foods in individual food containers are heated in a microwave oven, uneven heating may occur. As a result, the whole frozen food is not uniformly heated, and if the whole is heated to a required temperature, there is a disadvantage that an overheated portion is partially generated and the heating time is lengthened. The cause of the heating unevenness is greatly affected by the irradiation unevenness based on the characteristics of microwaves emitted from the magnetron of the microwave oven.

[0003] Frozen foods are generally stored frozen at a temperature of -18 ° C or less after cooking, and the water in the frozen foods before being heated by a microwave oven exists in the form of ice. The dielectric constant for waves is much lower than water,
It takes a considerable amount of energy to melt to water. However, once this ice melts and becomes water, the dielectric constant of microwaves rises sharply, about 400
It is said that it is easily heated twice. For this reason, when the frozen food is heated in a microwave oven, if a part of the water (ice) in the frozen food is first melted due to the uneven irradiation of the microwave, only that part is selectively heated, As a result, hot portions and cold portions are generated, and uneven heating occurs. For the purpose of preventing the uneven heating, in the case of frozen foods placed in individual food containers, attempts have been made to improve the shape and structure of the containers. For example, the container is raised to the bottom or a microwave impermeable material such as an aluminum foil film is adhered to the side wall of the container to prevent uneven heating (Japanese Patent Application Laid-Open No. 56-32261). Further, there is also known a method in which a separating wall is provided for each food in a container to perform differential heating suitable for each food (Japanese Patent Application Laid-Open No. 52-112150).

[0004]

In the case of frozen foods to be put into individual food containers, containers with raised bottoms as described above or containers with microwave impervious materials wound on the side walls are used. By this, the heating unevenness can be eliminated to some extent, but since the container structure becomes complicated, there is a problem of high manufacturing cost.On the other hand, since the food stored in the container is not heated from the inside, it is uniform, fast,
From the viewpoint of economical heating, there are still many problems to be improved. In particular, even if the improved individual food container as described above is used, even when it is not possible to heat the container all at once with a microwave oven or when a required amount is collected, it is necessary to heat the container uniformly. Because there is
For that purpose, the frozen food itself must be provided with a function of uniform heating. From such a fact, the present inventors examined whether or not the frozen food itself could be uniformly heated from the inside. As a result, they found that the frozen food contained an aqueous medium that did not freeze or contained an aqueous medium with a low freezing point, and when heated in a microwave oven, was heated in a short time and uniformly, and found that The invention has been completed. That is, an object of the present invention is to provide a frozen food which can be rapidly, uniformly and economically heated by a microwave oven, and a method for producing the same.

[0005]

SUMMARY OF THE INVENTION The present invention provides the following frozen food for microwave ovens in order to solve the above-mentioned problems. That is, the present invention is a frozen food for a microwave oven containing an antifreeze emulsified in a water-in-oil type and / or an antifreeze coated with a film material, wherein the antifreeze emulsified in the water-in-oil type is The edible oil is used as the oil phase and the antifreeze is used as the aqueous phase. The antifreeze covered with the film substance is encapsulated using the film substance as the outer skin and the antifreeze liquid as the core substance. The antifreeze contains a solute that lowers the freezing point of the aqueous medium when dissolved in the aqueous medium. The above solute is, for example, one or more selected from salt, sugar, glucose, fructose, starch syrup, isomerized sugar, trehalose, glycerin, sorbitol, maltitol, erythritol, ethyl alcohol, etc., and is suitable as an aqueous medium. Water, milks such as skim milk, or liquids such as fruit juice at room temperature are used. Further, the freezing point of the antifreeze is adjusted to -5 ° C or lower, preferably -10 ° C or lower depending on the concentration of the solute. Furthermore, the present invention produces the above-mentioned frozen food for a microwave oven by the following method. That is, the production method of the present invention dissolves a solute in an aqueous medium to lower the freezing point,
The freezing point of the aqueous medium is adjusted to −5 ° C. or less depending on the concentration of the solute to prepare an antifreeze, and the antifreeze is emulsified as an aqueous phase with edible oil or fat in a water-in-oil type, or coated with a coating substance as a core substance. This is a method for producing a frozen food for a microwave oven, which is encapsulated in a frozen food and then contained in the frozen food.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The present invention aims to obtain a frozen food that can be heated quickly, uniformly, and in a short time when heated by a microwave oven. Any material can be used as long as it can be heated. For example, gratins, soups, pizzas, croquettes, hamburgers, sauces, frozen foods that are heated in a microwave oven while still in individual food containers such as cooked rice such as pilaf, Frozen food that is distributed in a synthetic resin bag, transferred to a microwave oven container, and heated in a microwave oven may be used.

In the present invention, these frozen foods contain an antifreeze. The antifreeze is prepared by dissolving a solute in an aqueous medium and adjusting its concentration to reduce the freezing point.
The temperature is set to 5 ° C or lower, preferably -10 ° C or lower. Further, as the aqueous medium, water, milk such as skim milk, or a liquid such as fruit juice which is liquid at normal temperature is used. As a solute dissolved in the aqueous medium and constituting the antifreeze, any substance capable of lowering the freezing point of the aqueous medium by being dissolved in the aqueous medium can be used for food. Good. For example, salt, sugar, glucose, fructose, starch syrup, isomerized sugar, trehalose,
Glycerin, sorbitol, maltitol, erythritol, ethyl alcohol and the like can be mentioned, and it is preferable to use one or more of these. Further, the freezing point of the antifreeze is adjusted by adjusting the concentration of the solute as described above. However, since the concentration with respect to the freezing point differs depending on the type of the solute, it is preferable to experimentally determine the freezing point. According to the experimental results of the present inventors, for example, if the concentration of salt is 10
In the case of maltitol, the required concentration is 30% or more in terms of solid content.

[0008] Next, in the present invention, the antifreeze prepared as described above is used to emulsify the edible oil / fat as an oil phase and the antifreeze as an aqueous phase in a water-in-oil type, or use the antifreeze as an outer shell. Then, the antifreeze is encapsulated as a core substance. The reason for emulsifying or encapsulating in a water-in-oil type in this way is that when an antifreeze is blended with raw materials as it is, or when mixed with semi-finished products to prepare cooked frozen foods, it is diluted with water or blended water derived from raw materials. This is to prevent the function as an antifreeze from being reduced.

[0009] The method of emulsifying in a water-in-oil type is the same as the method of preparing margarine or spread by mixing edible oil and fat on the oil phase side and the antifreeze on the aqueous phase side and blending it with a lipophilic or hydrophilic emulsifier. It is prepared by a similar method. The edible oils and fats to be used as the oil phase include animal and vegetable oils such as soybean oil, rapeseed oil, cottonseed oil, olive oil, safflower oil, corn oil, lard, head, butter, and butter oil. Fats and oils to be added, fractionated fats and oils, and mixed fats and oils may be used, and one or more are selected from these. In addition, by adding spices and flavors together with the solute to the antifreeze as the aqueous phase and flavoring it, palatability can be enhanced. As the emulsifier, monoglyceride, diglyceride, organic acid monoglyceride, polyglycerin fatty acid ester, sugar ester, lecithin, polyglycerin condensed ricinoleate, etc., usually,
An emulsifier used when preparing a water-in-oil type emulsified fat or oil can be exemplified. Next, the above oil phase and aqueous phase are emulsified into a water-in-oil type using a homomixer, an emulsification pot, a high-pressure homogenizer, etc., and then cooled and kneaded as necessary.

[0010] The encapsulation method is prepared by coating an antifreeze with a film material, and examples of the film material serving as the outer skin include alginates and hardened fats and oils. In the case of encapsulation using an alginate as a film material, for example, it can be prepared by dissolving sodium alginate in an antifreeze and dropping the solution into a calcium chloride aqueous solution using a nozzle or the like. When the film material is a hardened oil, for example, using a triple concentric cylindrical tube nozzle, an antifreeze liquid as a core material from the inner cylindrical tube, and a molten hardened oil as a film material from the middle cylindrical tube,
And pressurized air from the outer cylindrical tube as a jet stream is sprayed into a cooling gas to encapsulate. Although other encapsulation methods can be adopted,
In the present invention, when leaching from the outer skin due to the osmotic pressure of the antifreeze, productivity and handleability at the time of coating the antifreeze, or considering the favorable taste of the obtained frozen food, Antifreeze liquid emulsified in water-in-oil with edible oils and fats,
Alternatively, an encapsulated antifreeze using hardened fat or oil as a film material is particularly preferably used.

In the present invention, as described above, the antifreeze emulsified and prepared in a water-in-oil type or the encapsulated antifreeze (hereinafter, both are collectively referred to as a coated antifreeze, but the emulsified antifreeze is an emulsified antifreeze, and the encapsulated antifreeze is referred to as an antifreeze. Encapsulated antifreeze) is mixed with the raw material, or in the semi-finished product stage, or in the frozen food after cooking and before freezing. The method is selected according to the characteristics of the frozen food. You. For example, in the case of gratin, it is only necessary to add a coating antifreeze to this white sauce after preparing the white sauce, and in a hamburger, mix the coating antifreeze with the raw dough,
What is necessary is just to cook and shape | mold after dispersing. Since the amount of the coated antifreeze contained in the frozen food varies depending on the type and amount of the solute mixed in the antifreeze, the taste, and the like, the optimum mixing amount is determined in consideration of these requirements.
The results of our experiments show that the above solutes are contained in antifreeze.
It was found that if the content was about 10%, the flavor was not affected even when about 2 to 10% was added.

[0012] In the frozen food containing the coated antifreeze obtained in this manner, the solute is diluted by the moisture or the preparation water derived from the raw material because the antifreeze is covered with the fat or oil or the coating substance and dispersed. Nothing. As a result, even if the frozen food is stored frozen at -18 ° C or lower, the antifreeze liquid is not frozen, or even if it is frozen, the freezing point is -5 ° C or lower. Thereby, when heated in a microwave oven, compared with the case where the moisture in the frozen food is crystallized, the effect that the dielectric constant of the microwave is much larger, and the microwave is heated quickly and uniformly can be obtained. .

[0013]

The present invention will now be described in detail with reference to examples, and test examples will be shown to clarify the effects of the present invention.

[0014]

Example 1 Preparation of Gratin ; (1) Preparation of White Sauce 20 kg of margarine was heated and dissolved, and then 15 kg of flour was added and heated to prepare a roux. This roux has 100 kg of raw milk,
Chemically modified starch 5kg, seasoning 4kg, emulsifier 3kg, spice 300g
And 422.7 kg of water were mixed and heated to 95 ° C. to obtain 570 kg of white sauce. (2) Preparation of emulsified antifreeze 3.3 kg of common salt is dispersed and dissolved in 11.7 kg of water to prepare 15 kg of antifreeze to form an aqueous phase, while 1 kg of emulsifier (monoglyceride) is dissolved in 14 kg of soybean salad oil and the oil phase is dissolved. The water phase and the oil phase were prepared and emulsified with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain 30 kg of a water-in-oil emulsion (W / O emulsion). The freezing point of this antifreeze was -20 ° C. (3) Preparation of Gratin The white sauce prepared above and the emulsified antifreeze are mixed and emulsified with a micro cutter (Model: MCH-20, manufactured by Stefan), and the emulsion is double emulsified (W / O / W type).
600 kg was obtained. From this white sauce, 150 g was taken, mixed with 50 g of boiled macaroni, filled into a plastic tray having a diameter of 150 mm, and topped with 10 g of shredded mozzarella cheese to prepare gratin.
This gratin was rapidly frozen and stored at −10 ° C. to obtain frozen gratin.

[0015]

Comparative Example 1 A frozen gratin of Comparative Example 1 was obtained in the same manner as in Example 1, except that the same weight of salad oil was used instead of the emulsified antifreeze used for preparing the gratin.

[0016]

Test Example 1 Using the gratin obtained in Example 1 and Comparative Example 1, a microwave oven (Model: NE-A740 manufactured by Matsushita Electric Industrial Co., Ltd.) was used.
A heating test was performed for 5 minutes, and the temperature rise at the midpoint between the outer peripheral side and the center of the container was measured every minute. Table 1 shows the results.

[0017]

[Table 1]

As is clear from Table 1, the frozen gratin of Example 1 containing the emulsified antifreeze has a larger increase in the initial temperature (after one minute) than the frozen gratin of Comparative Example 1; The heating time is reduced by about 1 minute or more to maintain the temperature rise rate by heating the microwave oven and raise it to a required temperature (90 ° C. or more). Therefore, the frozen food for microwave oven containing the emulsified antifreeze of the present invention,
Rapid heating was confirmed.

[0019]

Example 2 Preparation of cream croquette ; (1) Preparation of white sauce After heating and dissolving 4 kg of margarine, 4 kg of flour was added and heated to prepare a roux. 2K of modified starch
g, dextrin 8Kg, concentrated milk 10Kg, seasoning 1Kg, water 41K
g and heated to 95 ° C. to obtain 70 kg of white sauce. (2) Preparation of emulsified antifreeze 1 kg of maltitol (solid content 70%) is dispersed and dissolved in 1 kg of water to prepare 2 kg of antifreeze to form an aqueous phase, while 2.9 kg of rapeseed oil is emulsified (polyglycerin fatty acid ester). 0)
An oil phase was prepared by dissolving 1 kg, and the aqueous phase and the oil phase were emulsified with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain 5 kg of a water-in-oil emulsion (W / O emulsion). Obtained. The freezing point of this antifreeze was -18 ° C. (3) Preparation of cream croquette 5 kg of onion and 18 kg of corn are fried with 2 kg of butter, and this oil fried vegetable is mixed with the white sauce prepared in (1) and (2) above and an emulsified antifreeze to prepare a dough for cream croquette. 100 kg was obtained. The dough was packed in a casing, frozen at -26 ° C, and then cut to a length of 6 cm to prepare a bale-shaped seed. After immersing this sponge in a batter solution prepared by a conventional method and attaching it, bread crumbs were attached to the surface, and 190
Fried with salad oil for 2 minutes. Thereafter, the mixture was rapidly frozen and stored at −10 ° C. to prepare frozen cream croquettes.

[0020]

Example 3 A frozen cream croquette was prepared in the same manner as in Example 2. However, in place of the emulsified antifreeze used in Example 2, an encapsulated antifreeze prepared by the following method was blended. (1) Preparation of encapsulated antifreeze solution 3000g of maltitol (70% solids) and 60g of sodium alginate were mixed and dissolved in 2940g of water to prepare an antifreeze solution.
The solution was dropped into a 5% calcium chloride solution. The obtained microcapsules were separated by filtration, and 5 kg of the microcapsules was used for preparing a cream croquette.

[0021]

Example 4 A frozen cream croquette was prepared in the same manner as in Example 2. However, in place of the emulsified antifreeze used in Example 2, an encapsulated antifreeze prepared by the following method was blended. (1) Preparation of encapsulated antifreeze solution 3000 g of maltitol (solid content 70%) is mixed and dissolved in 3000 g of water to prepare an antifreeze solution, and this antifreeze solution is used as a core substance, while hardened palm oil having a melting point of 38 ° C is coated. Using a triple concentric cylinder nozzle, a jet stream of antifreeze as the core substance from the inner cylinder pipe, molten hardened oil and fat as the coating substance from the middle cylinder pipe, and pressurized air from the outer cylinder pipe, respectively. Was encapsulated by spraying into a gas cooled to 10 ° C. 5 kg of this was used for the preparation of cream croquettes.

[0022]

Comparative Example 2 The frozen cream croquette of Comparative Example 2 was obtained in the same manner as in Example 2, except that the same weight of soybean salad oil was used instead of the emulsified antifreeze used in the preparation of the frozen cream croquette. Was.

[0023]

Test Example 2 Each of the frozen cream croquettes obtained in Examples 2, 3, and 4 and Comparative Example 2 was placed on a plate and heated in a microwave for 1 minute and 30 seconds. As a result, Examples 2, 3, and 4
The frozen cream croquette prepared in Example 1 was uniformly heated to 85-90 ° C., while the frozen cream croquette prepared in Comparative Example 2 had a center at 98 ° C. but a peripheral portion of the garment at 50 ° C.
The temperature rose only to about ° C., causing temperature unevenness.
Furthermore, if heating is continued until the temperature around the clothing reaches 85-90 ° C,
Heating of the central part was promoted, resulting in an overheated state, and the garment cracked and some of the seeds protruded.

As described above, in the case of frozen foods such as cream croquettes, if the whole is heated to a temperature required for ingestion, overheating may occur due to uneven heating, thereby deteriorating the commercial value such as protruding middle-class. Occur. However, in the cream croquettes of Examples 2, 3, and 4, the heating time is uniform, so that the heating time to the temperature required for ingestion can be shortened and can be set to a constant value. Can be obtained.

[0025]

According to the present invention, there is provided a frozen food which can rapidly and uniformly heat the inside of the food. In addition, since a container having a special shape or structure is not required for uniform heating, uniform heating of the frozen food for a microwave oven can be economically achieved. That is, in the frozen food for a microwave oven of the present invention, the antifreeze liquid obtained by dissolving a solute in an aqueous medium and having a freezing point is emulsified in a water-in-oil type, or encapsulated by coating with a film substance and blending. ing. For this reason, -18
If the antifreeze solution is not frozen even when stored frozen at
Even if frozen, the freezing point is -5 ° C or less, and when heated in a microwave oven, the dielectric constant of microwaves is much larger than that of frozen foods in which water is only crystallized, and rapid, In addition, there is an effect that heating is performed uniformly. In other words, the cooking time can be shortened, and the cooked food is always in a good condition not only in appearance but also in flavor, which is of great practical benefit.

Claims (7)

[Claims] 1. Frozen food for a microwave oven, comprising an antifreeze emulsified in a water-in-oil type and / or an antifreeze coated with a film material. 2. The frozen food for a microwave oven according to claim 1, wherein the antifreeze emulsified in a water-in-oil type is prepared by using an edible fat as an oil phase and an antifreeze as an aqueous phase. 3. The frozen food for a microwave oven according to claim 1, wherein the antifreeze liquid coated with the coating substance is encapsulated with the coating substance as an outer skin and the antifreeze liquid as a core substance. 4. The frozen food for a microwave oven according to claim 1, wherein the antifreeze contains a solute that lowers the freezing point of the aqueous medium when dissolved in the aqueous medium. 5. The solute comprises salt, sugar, glucose, fructose,
The frozen food for a microwave oven according to any one of claims 1 to 4, comprising at least one selected from syrup, isomerized sugar, trehalose, glycerin, sorbitol, maltitol, erythritol, ethyl alcohol and the like. . 6. The frozen food for a microwave oven according to claim 1, wherein the freezing point of the antifreeze is adjusted to -5 ° C. or lower. 7. An antifreeze solution is prepared by dissolving a solute in an aqueous medium to lower the freezing point, adjusting the freezing point of the aqueous medium to -5 ° C. or lower depending on the concentration of the solute, and using the antifreeze solution as an aqueous phase to produce edible oils and fats. A method for producing a frozen food for a microwave oven, comprising emulsifying the mixture in a water-in-oil type, or coating with a film substance as a core substance, encapsulating the substance, and then incorporating the resulting substance into a frozen food.