JPH05137550A - Method for treating food ingredient under high pressure - Google Patents

Abstract

PURPOSE:To effectively utilize phenomena of partial melting of ice and temperature drop caused by pressurizing for pressure sterilization of water-containing food ingredient. CONSTITUTION:A material 7 to be treated is made into a frozen state, wrapped with a heat insulating member 8 and pressurized under isotropic pressure in a high-pressure chamber 6 of a high-pressure container 1 in a state free from permeation of a pressure medium 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for high-pressure treatment of food materials, and more specifically, a pressure treatment for sterilization and sterilization of an object to be treated such as food containing water. The present invention relates to a method for efficiently performing in a low temperature range.

[0002]

2. Description of the Related Art In conventional food processing, heat is almost always used as a physical variable for processing, and pressure is incidentally derived from thermal action. .. Recently, however, the utilization of pressure for food processing has attracted attention, and research and development are progressing. In this case, it is attempted to cause temperature to act synergistically with pressure.

For example, it is known from JP-A-62-69969 that, for the purpose of sterilization, it is more efficient than pressurizing at room temperature not only on the heating side but also on the cooling side. As a device for applying such pressure and temperature to food, there is a known warm isostatic pressurizing device, which generally controls the temperature by circulating a heating medium outside the high-pressure container. Is. This device is also capable of pressurizing at low temperature by circulating a refrigerant, and immersing the object to be processed in the cooled pressure medium of the device to pressurize it. It can be performed.

However, since such a temperature control method attempts to control the temperature from the outside of a thick high-pressure container having a large heat capacity, it takes an extremely long time to reach a thermal equilibrium state. Despite the experimental equipment, it was extremely inefficient as a production device. As a method of avoiding such a problem, for example, regarding cooling, the apparatus described in Japanese Patent Application Laid-Open No. 2-182157, that is, a large number of tube groups are provided inside a high-pressure container to circulate a refrigerant and pressurize the medium. A device for cooling the air conditioner has been proposed, and the above-mentioned problem is once improved (conventional example 1).

[0005]

However, in the conventional example 1, the arrangement of the tube groups inside the high-pressure container becomes more difficult as the pressure becomes higher, and an extra space is required in the high-pressure container, which causes a problem in the high-pressure container. There is a problem that the volume utilization efficiency of the inside decreases. Therefore, the present invention provides a method for performing a pressure treatment for the purpose of sterilizing an object to be treated such as food containing water efficiently in a low temperature range and without using a large apparatus as described above. The purpose is to provide.

[0006]

According to the present invention, an object to be treated 7 such as food containing water is pressurized in a high pressure chamber 6 of a high pressure vessel 1 with a pressure medium 10.
In order to achieve the above-mentioned object in the method of applying pressure treatment under isotropic pressure, the following technical measures are taken. That is, the present invention puts the article to be treated 7 in a frozen state,
In addition, the pressure medium 10 is wrapped in a flexible heat insulating member 8 and is immersed in the pressure medium 10 in a state in which the pressure medium 10 is prevented from entering.
It is characterized in that pressure treatment is carried out under 10 isotropic pressure.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, in which a piston 2 having a packing 4 is inserted into the upper opening of a cylindrical high-pressure vessel 1, while the lower opening of the high-pressure vessel 1 is inserted. A lower lid 3 having a packing 5 is attached, and a high pressure chamber 6 is formed in the high pressure container 1 by these.

Although not shown in the figure, the piston 2 is configured as a hydraulic cylinder, and is compressed downward by hydraulic pressure to compress the pressure medium 10 in the high pressure chamber 6,
It constitutes a so-called piston type pressurizing device that generates isotropic pressure. The axial force acting on the piston 2 and the lower lid 3 is supported by a rectangular frame, though not shown. Thus, from the point of view of hygiene, the object 7 to be treated such as fish meat, livestock meat, etc. containing water is first frozen in a sealed state such as a retort pouch, and then the periphery thereof is covered with a flexible heat insulating material. , For example, it is wrapped with a mat-shaped heat insulating material 8 and the outer periphery thereof is also wrapped with a flexible polyethylene bag 9 to prevent the pressure medium 10 from entering,
It is immersed in the pressure medium 10 in the high-pressure chamber 6 and subjected to pressure treatment.

With the above-mentioned constitution, the water content in the frozen food is, for example, at -5.degree.
If it is pressurized to 2000 kgf / cm ^{2, a part of} it melts under pressure along the solid-liquid transformation line between ice I and water in the state diagram of water shown in FIG. After cooling, the temperature drops to about -20 ℃. This is a fact that has been experimentally confirmed.

[0010] Therefore, the effect of pressurization and sterilization is further enhanced as the temperature drops, and also the heat insulation effect against the intrusion of heat from the external pressure medium in the room temperature state, for example, during the pressure retention. Together, since the remaining frozen water content is maintained at least -20 ° C to 0 ° C until it is completely thawed, efficient sterilization using low temperature can be performed in a very simple manner without using a large-scale device configuration. It can be done. Also, from the behavior of ice under pressure (partial melting along the solid-liquid transformation line and temperature drop due to latent heat), even if the temperature in the initial frozen state is near 0 ° C, the heat insulating effect of the heat insulating material 8 Also, due to the heat shielding effect, it is possible to easily create a low temperature state by pressurizing and maintain the low temperature state.

When the object to be treated 7 is in the form of a liquid, a container 13 having a ring-shaped flange 15 and a bellows-shaped tube portion 16 is provided with a seal 14 on a lid 13 having a stopper 13A. Removably assembled with, the inside of the lid 13 and the container 12 is provided with fluororesin coats 11 and 11A for heat insulation, and the liquid object 7 is injected into this container 12 and is closed in a frozen state. However, the same effect can be obtained even if the pressure treatment is performed thereafter.

The container 12 itself may be made of a material such as fluororesin and formed into a bellows shape. Please add the attached example. Example 1 Escherichia coli (E. coli) was added to a physiological saline solution (0.9% NaC).
After washing with l), a cell suspension of about 10 ⁸ / ml was prepared. Take 50 ml of this, put it in a polyethylene bag and pack it, and then test the sample (diameter 40 mm x length 40 m
m). This was frozen at −7 ° C., immersed in a hydraulic medium at −7 ° C. as it was, pressurized to 2 kb, kept for 20 min, and after decompression, the number of surviving bacteria was measured, and the survival rate was 2.1 × 10 5.
It became ^-6 . Example 2 The test piece of Example 1 was wrapped with a mat-shaped heat insulating material having a thickness of 10 mm, further sealed in a polyethylene bag, frozen under the same conditions as in Example 1, and subjected to pressure treatment. As a result, the survival rate was 8.1 × 10 ⁻⁸ , and a bactericidal effect higher than that of Example 1 was confirmed. The test piece of Example 1 was frozen at -20 ° C and immersed in a hydraulic medium at -20 ° C to obtain 2 kb and 20 m.
The survival rate when pressurized in was 2.1 × 10 ⁻⁸ , and the above results were judged to be sterilization at a temperature equivalent level.

[0013]

EFFECTS OF THE INVENTION The present invention is as described above, wherein an object to be treated such as food containing water is put in a frozen state and wrapped with a flexible heat insulating member, and a pressure medium is provided inside the heat insulating member. By performing pressure treatment so that it does not intrude, the temperature during pressure retention becomes lower than the initial temperature due to the partial melting of ice under pressure and the temperature drop due to latent heat and the heat insulation and heat insulation effect. It can be maintained and sterilized efficiently and economically with a simple structure, and it can greatly contribute to the spread of the technical field.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the behavior of ice under pressure.

FIG. 3 is a modified cross-sectional view of an object to be processed wrapped with a heat insulating material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-pressure container 2 Pressurizing piston 6 High-pressure chamber 7 Processed object 8 Thermal insulation member 10 Pressure medium

Claims (1)

[Claims] 1. A method for pressurizing an object to be treated (7) such as food containing water in a high-pressure chamber (6) of a high-pressure container (1) by a pressure medium (10) under isotropic pressure. The processed material (7) is placed in a frozen state, wrapped with a flexible heat insulating member (8), and immersed in the pressure medium (10) in a state in which the pressure medium (10) is prevented from entering. A method for high-pressure treatment of food materials, characterized in that the medium (10) is subjected to pressure treatment under isotropic pressure.