JPH05115266A - Thawing of frozen food - Google Patents

Abstract

PURPOSE:To carry out the thawing of a frozen food with a simple, compact and easily maintainable apparatus in shortened thawing time by immersing a frozen food in water and blowing fine bubbles from a porous membrane member into the water from the bottom. CONSTITUTION:A porous membrane member composed of a hollow fiber bundle 11 made of a polymer (e.g. polysulfone) and having a number of pores of 100-1,000Angstrom diameter on the whole surface of the fiber is placed in a water tank 1 for immersing a frozen food 16. Fine bubbles of about 100mum diameter are generated from the porous member placed under the frozen food 16 and the food is thawed in the water containing the fine bubbles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for thawing frozen food.

[0002]

2. Description of the Related Art There is a water immersion thawing method as a thawing method for frozen foods, and a foaming type water immersing thawing method is known in which bubbles are generated in a water tank to shorten the thawing time. This method has an advantage that it is possible to remove sand, foreign matter, etc. adhering to the product to be thawed. As a conventional method of generating bubbles in the water tank, a method of ejecting air into the water from a nozzle of a pipe by an air compressor is known.

[0003]

In the above conventional bubble generating method, since the bubble diameter is large and the heat boundary cannot be broken, the overall heat transfer coefficient cannot be improved so much. Thawing efficiency cannot be obtained.

The present invention has been made in view of the above, and the method for thawing frozen foods can further shorten the thawing time by generating extremely fine bubbles and mixing them in water. It is intended to provide.

[0005]

In order to achieve the above object, a method for thawing frozen food according to the present invention is a method for thawing frozen food by a water immersion thawing method, wherein frozen food 16 is frozen in water. Fine bubbles of about 100 μm are generated from the lower part of the food from the porous membrane member made of a polymer material, and the fine bubbles are mixed in water. A hollow fiber was used for the porous membrane member.

[0006]

[Operation] Micro bubbles mixed in water disturb the boundary between frozen food and water, and improve the overall heat transfer coefficient, which shortens the thawing time of frozen food.

[0007]

[Example] An example of the present invention will be described with reference to FIG. In the figure, 1 is a water tank partitioned by a partition 2 into a thawing chamber 3 and a filtration chamber 4, and 5 is a circulation line for circulating water 6 in the water tank 1. The circulation line 5 is a pump 7 and a bubble generator 8 And an air compressor 9. A filter 10 is installed above the filtration chamber 4. The height of the partition 2 is lower than the side wall of the aquarium 1,
The water 6 flowing into the thawing chamber 3 overflows from the partition 2 and flows into the filtering chamber 4 side. The bubble generator 8 is installed at the bottom of the thawing chamber 3, and the bubble generator 8
Is a plurality of hollow fiber bundles 11, and both ends thereof are molded materials 12
It is supported by and is housed in the tubular body 13. At one end of the tubular body 13, a gas chamber 14 facing one end of each hollow fiber bundle 11 and a running water chamber 15 between the molding materials 12, 12 are configured. Has been done. The air compressor 9 is connected to the gas chamber 14, the outlet side of the pump 7 is connected to one end of the running water chamber 15, and the other end of the running water chamber 15 is opened to the bottom of the thawing chamber 3. There is. The inflow pipe of the pump 7 is connected to the bottom of the filtration chamber 4.

The hollow fibers constituting the hollow fiber bundle 11 are
The inner and outer surfaces are made up of a dense film, and the thick inside is made up of a sponge, and the film on both surfaces is 100-1000.
There are many holes of about Angstrom on one side.
This hollow fiber is usually produced by a dry and wet spinning method using a solution prepared by dissolving a polymer material in the solvent and adding a pore-forming agent thereto. For example, polysulfone P-1700 (manufactured by Union Carbide Co., Ltd.) was dissolved in N-methyl-2-pyrrolidone, and a solvent prepared by adding ethylene glycol as a pore-forming agent was used. In addition to the hollow fibers, a film-shaped porous membrane member can also be manufactured by the manufacturing method as described above. The porous membrane member including the hollow fibers is, as shown in FIG.
In the membrane members a, b, c having different membrane members materials, manufacturing conditions, etc., the diameter of bubbles generated from the membrane members a, b, c depending on the air pressure and the amount of the membrane members, the amount of flowing water, and the installation angle for the flowing water Can be adjusted.

In the above structure, the air compressor 9
When air is sent from the pump 6 and the water 6 in the water tank 1 is circulated in the circulation line 5 by the pump 7, pressurized air is supplied to the inside of each hollow fiber of the hollow fiber bundle 11 of the bubble generator 8, and the running water chamber 15 is supplied from the outside.
Fine bubbles are generated in the running water inside and the water 6 in the thawing chamber 3
Is supplied to. At this time, excess water in the thawing chamber 3 overflows the partition 2 and flows into the filtering chamber 4. At this time, dust in the water is removed by the filter 10. In addition, drainage pipes and water supply pipes for discharging and supplying water from the water tank 1 are
It is installed at an arbitrary position in the water tank 1 according to its intended effect. Furthermore, the structure, shape, etc. of the bubble generator 8 shown in the above example are only examples, and the present invention is not limited to this.

By the above action, the fine air bubbles mixed in the water disturb the boundary between the frozen food 16 and the water 6 to improve the overall heat transfer coefficient, and the frozen food 16 immersed in the water is quickly thawed. It FIG. 3 is a diagram showing a comparison of the thawing time between the conventional foaming type water immersion thawing method and the thawing method according to the present invention, in which the vertical axis represents the core temperature of frozen products and the horizontal axis represents time. In the figure, B shows the core temperature of the frozen product in the conventional foaming type water immersion thawing method, and A shows the core temperature of the frozen product in the thawing method according to the present invention. At this time, as the frozen product, jelly of 150 × 150 × 24 cm was used. As shown in FIG. 3, the thawing time (time until reaching 0 ° C.) in the thawing method according to the present invention was about 1.5 times faster than the thawing time in the conventional foaming type water immersion thawing method.

[0011]

According to the present invention, the thawing time can be shortened as compared with the conventional foaming water immersion thawing method. Structurally, since the porous membrane member itself is extremely small, the bubble generator 8 itself becomes extremely compact, and the air pressure sent to this bubble generator 8 is as small as about 2 kg / cm ² , so the air compressor 9 is also small. I need only one. Furthermore, since the water flow may be small, a small pump 7 is sufficient. Therefore, the entire defrosting device used in the method of the present invention is extremely compact, and it does not need to be installed at any place, and the configuration can be further simplified. Further, in terms of energy, only low pressurized air is required, and the air compressor 9 and the pump 7 can be made small, so that the energy required is smaller than in the past. Furthermore, since the entire amount of supply air becomes fine bubbles and is generated in water, excess air is eliminated and efficiency is improved. Furthermore, according to the mechanism of the bubble generator 8 of the present invention, it is possible to adjust the bubble density to an arbitrary value. Further, since water itself cannot pass through this membrane member, maintenance is not required for dust in the water, and since the entire structure is simple, maintenance such as replacement of parts is easy.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an example of an apparatus for carrying out the method of the present invention.

FIG. 2 is a diagram showing bubble diameters with respect to air pressure and flowing water amount in different membrane members.

FIG. 3 is a diagram showing a thawing time in a conventional example and the method of the present invention.

[Explanation of symbols]

1 ... Water tank, 2 ... Partition, 3 ... Thawing room, 4 ... Filtration room, 5 ...
Circulation line, 6 ... Water, 7 ... Pump, 8 ... Bubble generator, 9
... Air compressor, 10 ... Filter, 11 ... Hollow fiber bundle, 12 ... Mold material, 13 ... Cylindrical body, 14 ... Gas chamber, 1
5 ... running water chamber, 16 ... frozen food.

Claims (2)

[Claims] 1. A method of thawing frozen foods by a water immersion thawing method, wherein fine bubbles of about 100 μm are generated from the bottom of the frozen foods in a water into which the frozen foods 16 are immersed, from a porous membrane member made of a polymer material. A method for thawing frozen food, characterized in that fine air bubbles are mixed in water. 2. The method for thawing frozen foods according to claim 1, wherein hollow fibers are used for the porous membrane member.