JP2013100965A - Cooling and cryopreservation method and cooling and refrigerating device for food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problems: food is supercooled or frozen at -5°C or lower, and it is difficult to control the fool refrigerated for preservation, and it is difficult to restore the frozen food to its original state during thawing.SOLUTION: Food containing water, e.g., filled Tofu T, is supercooled or frozen with ultrasonic vibration while physically restraining it to prevent expansion. For example, a sealed container 9 filled with non-compressible fluid (alcohol A) or a granular aggregate P is used for restraining the food.

Description

  The present invention relates to a method for cold storage of food, particularly food containing water, and an apparatus for carrying out the method.

Vegetables, seafood, meat, and these processed foods are less prone to bacterial growth at -5 ° C or lower, and the chemical reaction of the tissue is purified. It is recommended to prevent corrosion and deterioration by refrigerated storage and freezing.
However, it is usually supercooled or frozen at -5 ° C. or lower, and its management is difficult when refrigerated. In addition, in the case of freezing, the structure is easily damaged due to expansion caused by a rapid decrease in density during crystallization of the contained water, and the drip flows out or ice marks are formed during thawing. Is difficult.
In particular, it was difficult to restore a relatively high amount of water, such as tofu, to its original state upon thawing.

  In the case of freezing, as a method of preventing tissue damage, supercooling is performed by oscillating water molecules in cells by applying weak energy in a magnetic field or high voltage energy environment while cooling food. A refrigeration system is introduced that is described as being able to suppress crystallization of moisture by keeping it in a state and then freezing it instantaneously. Thus, even with this method, the restoration of the original state is insufficient for foods such as tofu containing a relatively large amount of water.

  Therefore, in order to solve the above-mentioned problems, the present invention has an object to propose a new and useful method suitable for cooling and freezing storage of food containing water, and an apparatus for carrying out the method. .

As a method of using the ultrasonic wave, it is known that the foreign matter adhered to the object is resonated with the frequency of the ultrasonic wave to be separated and removed, or liquids that are difficult to mix are mixed together. By applying ultrasonic vibration to food cooling and placing the food in physical restraint,
(1) The freezing temperature can be lowered to stably maintain the supercooled state,
(2) The present inventors have found that even when frozen, ice crystals are refined to prevent tissue damage and to be easily recovered.
The present invention has been completed based on the above findings.

The invention of claim 1 of the present invention is a cooling / freezing storage method characterized in that a food containing moisture is supercooled or frozen while applying ultrasonic vibration under physical restraint that suppresses expansion. .
The invention of claim 2 is the cooling / freezing storage method according to claim 1, wherein the freezing is performed by releasing ultrasonic vibration and / or restraint.

According to a third aspect of the present invention, in the apparatus for carrying out the cooling / freezing preservation method according to the first or second aspect, a closed container filled with an incompressible fluid or a granular aggregate is provided for restraining food. It is a cooling and refrigeration equipment characterized.
According to a fourth aspect of the present invention, there is provided an apparatus for carrying out the cooling / freezing preservation method according to the first or second aspect, wherein a mold having a recess corresponding to the shape of the food is provided for restraining the food. -A refrigeration system.
According to a fifth aspect of the present invention, in the cooling / freezing apparatus according to the fourth aspect, the mold is made of a porous material having a high heat dissipation thermal conductivity.

According to the method of the present invention, even when food is stored in a refrigerator, the supercooled state can be maintained more stably than in the conventional method, and when the food is stored in a frozen state, the original state is easily recovered.
Considering the distribution situation of goods, it is often stored frozen, but according to the method of the present invention, even if it contains a relatively large amount of water such as tofu, etc., it was not suitable for conventional frozen storage. Can be a target.

It is an image figure of the 1st type cooling and freezing apparatus of this invention. It is an image figure of the 2nd type cooling and freezing apparatus of this invention. It is a result report figure of Example 1. FIG. It is a result report figure of Example 1. FIG. 3 is a comparative photograph of the product of Example 1. It is a result report figure of Example 2. FIG. 3 is a comparative photograph of products of Example 2. 10 is a comparative photograph of products of Example 3.

The food to be treated contains water, and examples thereof include vegetables, seafood, meat, and processed foods such as tofu and pudding.
If the food can maintain its shape as a molded product by itself, if it is difficult or impossible to maintain such as tofu or pudding, put it in a container. After being molded, it will be used for processing. Here, the formability means that it can be handled, and may be deformed.

  In the present invention, the food is supercooled while applying ultrasonic vibration under physical restraint that suppresses expansion. Then, when reaching freezing, the ultrasonic vibration or restraint or both are released.

The frequency of the ultrasonic vibration to be applied is not particularly limited and includes all of the general range of 15 to 200 kHz. However, in order to facilitate resonance with moisture contained in the food to be processed, The optimum range varies depending on the situation.
The ultrasonic vibration may be directly applied to the food to be processed, but it is efficient to surround the food with a propagation medium and apply it through this medium. This is because the action of the ultrasonic wave is easily spread over the food by passing the medium.
When food is cooled or frozen, it is usually brought into contact with a refrigerant to exchange heat, so it is convenient to use the above-described propagation medium together with this refrigerant. For example, if it can be normally used as a brine in a cooling system, it can also be used in the present invention.

In order to physically restrain food, the following means can be considered.
(1) Put food in an airtight container filled with incompressible fluid or granular aggregates.
It is assumed that this fluid or granular aggregate can also function as the above-described propagation medium and refrigerant. For example, the fluid includes alcohol, a 2.5% bittern solution, a brine such as 3.3% saline, and the granular aggregate includes glass particles or shot blast metal particles. It is inefficient to give the above-described functions as a propagation medium or a refrigerant only with the granular aggregate, but it may be possible within a limited range within the sealed container.

The apparatus that can be used for carrying out the method of the present invention enables the above-described ultrasonic vibration, heat exchange with a refrigerant, and physical restraint of food at the same time. FIG. It is a thing. The food to be processed is infused tofu T.
In the cooling / freezing apparatus 1, an ultrasonic oscillator 5 and a heater 7 are attached to the bottom of the apparatus body 3. A sealed container 9 is accommodated in the apparatus body 3. The sealed container 9 can be opened and removed by opening the upper lid, but once sealed, it is not easily opened even if it is pressurized from the inside. The sealed container 9 is made of an aluminum material having good heat dissipation and ultrasonic wave propagation. The apparatus main body 3 is filled with alcohol A, the closed container 9 is filled with alcohol A in FIG. 1 (1), and the granular aggregate P is filled with FIG. 1 (2).

In the cooling / freezing apparatus 1, the brine is controlled by turning the heater 7 on and off.
Ultrasonic vibration is transmitted from the ultrasonic oscillator 5 to the injected tofu T through the alcohol A and the sealed container 9, and heat exchange is performed through the alcohol A and the sealed container 9.

(2) A mold having a recess corresponding to the shape of the food is manufactured, and the food is attached to the mold during processing.
The mold is made of a porous material having high heat dissipation conductivity, for example, a porous aluminum flat plate material that is perforated, and allows ultrasonic penetration.

  FIG. 2 is an image of the cooling / freezing apparatus 11 provided with the above-described restraining means. As an example, the food to be processed is infused tofu T. In this cooling / freezing apparatus 11, an aluminum porous mold 13 is provided in place of the above-described sealed container 9 of the cooling / freezing apparatus 1, and this mold 13 is filled with injected tofu T. The mold 13 is porous and is considered so that it can easily exchange heat with the alcohol A and allows ultrasonic waves to penetrate.

(Example 1: Injection tofu)
As shown in FIG. 3, the cooling / refrigeration apparatus 1 having the above configuration inserts needle-like CH1 (core temperature sensor), CH2 (resistance value sensor), and CH3 (refrigerant temperature sensor) to cool or freeze. The experiment was conducted.
Changes in resistance value of the article to be frozen are measured and recorded by the resistance value sensor, indicating that freezing starts at −10 ° C. and complete freezing at −15 ° C.
In this example, the temperature of the alcohol A was controlled so that the core temperature was maintained at about −5 ° C. during supercooling. The ultrasonic vibration was set to 40 kHz. Further, as a control, an experiment was also performed using the injected tofu T as it was in the apparatus main body 3 as shown in FIG.

When stored under cooling, the resistance value of the apparatus in FIG. 3 (invention) is around −5 ° C. and the overcooling state is stable, but in the apparatus of FIG. 4 (control (prior art)), the resistance is It shows that the value is further decreased below the −15 ° C. scale, and the direction of the decrease is abrupt, that is, the freezing speed is high and the frozen state is entered relatively soon.
When frozen, the freezing rate was relatively slow in the apparatus of FIG. 3 (present invention).

  FIG. 5 is a photograph of the ultrasonic vibration and physical restraint being released, and thawing by immersing in ice water. What was processed with the apparatus of FIG. 3 (invention) was glossy, elastic and smooth. On the other hand, what was processed with the apparatus of FIG. 4 (control (prior art)) remained ice marks, lost elasticity, and had a rough feeling. This is probably because the network structure was destroyed by the development of ice crystals.

(Example 2: frozen tangerine)
Using the cooling / refrigeration apparatus 1 having the above-described configuration, as shown in FIG. 6, instead of a sealed container, mandarin oranges are put in a freezer bag 15 and vacuum packed, and needle-like CH1 (core temperature sensor), CH2 to CH4 (Resistance value sensor) was inserted, and an experiment of supercooling or freezing was performed. In this example, the ultrasonic vibration was set to 40 kHz. Further, as a control, the experiment was also performed under the condition that no ultrasonic vibration was applied, that is, no vibration was applied.
In the presence of vibration, the freezing rate slowed as shown in the change in resistance value, and the progress of freezing varied depending on the site. On the other hand, without vibration, the freezing rate was relatively fast, and the progress of freezing was uniform regardless of the site.
Further, as shown in FIG. 7, after thawing, there was little “wetting” of the skin with the vibration, but considerable “wetting” of the skin without the vibration. The amount of “wetting” corresponds to the amount of drip at the time of thawing, and it can be seen from this result that the amount of drip was considerably suppressed with vibration.

(Example 3: Tuna fillet)
In the same manner as in Example 2, an experiment for supercooling or freezing was performed. After that, when it was immersed in ice water and thawed, as shown in FIG. 8, after the thawing, there was almost no drip in the method of the present invention, but in the conventional control product (prior art), a considerable amount of drip appeared. confirmed.

The embodiment of the present invention has been described in detail above. However, the specific configuration is not limited to this embodiment, and the present invention can be changed even if there is a design change without departing from the gist of the present invention. included.
For example, the cooling / refrigeration apparatus disclosed above is of laboratory level, and the specific structure will be different from that actually marketed. However, commercially available cooling / freezing apparatuses are also included in the scope of the present invention as long as all the ideas of the present invention are embodied.

  Even if the product has a lot of water, it can be restored to its original state after thawing or returned to a state close to it, so that the number of products that can be stored frozen increases. For example, a place like school lunch can be expected to offer something like a cold guy.

DESCRIPTION OF SYMBOLS 1 ... Cooling / refrigeration apparatus (1st type) 3 ... Apparatus main body 5 ... Ultrasonic oscillator 7 ... Heater 9 ... Sealed container 11 ... Cooling / refrigeration apparatus (2nd type) 13 ... Porous type 15 ... Freezer pack A ... Alcohol P ... granular aggregate T ... injected tofu

Claims (5)

  A cooling / freezing storage method characterized in that a food containing moisture is supercooled or frozen while applying ultrasonic vibration under physical restraint that suppresses expansion.   2. The cooling / freezing storage method according to claim 1, wherein the freezing is performed by releasing ultrasonic vibration and / or restraint.   3. A cooling / freezing apparatus for carrying out the cooling / freezing storage method according to claim 1 or 2, further comprising a sealed container filled with an incompressible fluid or a granular aggregate for restraining food. .   The apparatus for carrying out the cooling / freezing preservation method according to claim 1 or 2, wherein a mold having a recess corresponding to the shape of the food is provided for restraining the food.   5. The cooling / freezing apparatus according to claim 4, wherein the mold is made of a porous material having high heat dissipation.