JPH0242454B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention allows the shelled shellfish, which is soft and easily deformed, such as raw oysters, to be well preserved without deforming their original, unique shapes. This article relates to a method for freezing individual pieces of food.

Frozen foods are generally conveniently frozen so that they can be easily thawed, weighed at the time of sale, and dispensed into portions at the time of use. For this reason, small pieces of food, such as beans and cooked rice, are frozen using IQF in a so-called bulk state in which individual particles are separated.
(Individual Quick Frozen) Commercialized as a frozen product.

For this reason, it has been proposed to freeze the shells of shellfish such as raw oysters individually as described above. However, shellfish such as raw oysters that have been shucked are extremely flexible and are easily deformed, resulting in them being frozen into irregular shapes. For example, raw oysters are separated and lined up individually on a conveyor belt and frozen in a freezing device cooled to a low temperature, or they are placed in a molded container (tray) with recesses and frozen in a freezer. The bottom of raw oysters in contact with the belt conveyor or tray surface is deformed due to its own weight, causing the bottom to become flat and lose its unique appearance.Furthermore, when a net conveyor such as a wire mesh is used, the bottom surface of raw oysters becomes deformed. They dig into the mesh and leave traces of the mesh on the bottom surface of the raw oysters, reducing the product value. Furthermore, in each of the above-mentioned methods, the frozen raw oysters adhere to the belt conveyor and tray surface at the end of freezing, so it is necessary to peel them off one by one, which not only makes the work complicated, but also makes this peeling work difficult. In this process, the thin outer skin of raw oysters is often damaged, which is an inconvenience that further reduces the commercial value of raw oysters.

The present invention was made in view of the above-mentioned current situation, and its purpose is to remove the shelled shellfish, which is flexible, such as the shelled raw oyster, without deforming the unique shape that they originally possess. To obtain frozen products whose commercial value is significantly improved by reducing inconveniences such as damage and individually freezing them in extremely good condition. And its characteristic is that it is made by individually peeling shellfish shells, which are flexible like raw oysters.
It is dropped into a cryogen such as low-temperature liquefied gas, liquid cryogen, or snow-like dry ice and immersed in it, and after the surface is frozen to a specific shape, it is placed on a tray or belt conveyor and mechanically frozen. Each solid is individually separated and completely frozen to a temperature of -25℃ or lower using a machine or an atmosphere refrigeration device sprayed with low-temperature liquefied gas.Then, each solid is individually immersed in water at about 0℃ and glazed as appropriate. They are processed and frozen individually.

Hereinafter, the freezing method of the present invention will be described in detail with reference to the drawings, illustrating one embodiment of peeled raw oysters.

The drawings illustrate one embodiment of an apparatus for carrying out the process of individually freezing shucked raw oysters according to the present invention. First, drain the water from the raw raw oysters A and scoop them out from the water tank 1 where they are stored, place them on the supply belt conveyor 2 so that each individual raw oyster and shucked A is separated, and place it in liquid nitrogen. It is transported to a cryogen storage tank 4 in which a cryogen 3 such as a low-temperature liquefied gas with a low boiling point such as (boiling point about -196°C) is stored. In addition to liquid nitrogen, the cryogen used is liquid argon (boiling point approximately -186°C) or even -50°C.
Low-temperature liquid cryogens such as propylene glycol (boiling point about -50℃) cooled below ℃, and even snow-like dry ice (boiling point about -78℃),
Preferably, a cryogen that absorbs the impact caused by a fall is used. The shucked raw oysters A transported by the supply belt conveyor 2 are immersed in the cryogen 3 stored in the cryogen storage tank 4 from the end of the supply belt conveyor 2, with each individual piece being individually stored in the storage tank 4. cooled by direct contact. At the time of this dropping, the shelled raw oyster A is thrown into the air, so the load due to its own weight is released, it restores its original posture, is immersed in the cryogen 3, and comes into direct contact with the cryogen 3. When cooled, it retains its unique form and freezes rapidly. Since the cryogen 3, such as the low-temperature liquefied gas, is kept at an extremely low temperature as described above, the peeled raw oyster A, which is the product to be frozen, is rapidly cooled and retains its original shape as described above. It is frozen in
If it is left in the extremely low temperature of the cryogen 3 until freezing is completely completed, it will be overcooled, resulting in cracks in the shucked raw oysters A, making it a defective product and reducing its commercial value. Therefore, it is preferable that raw shucked oyster meat A is frozen to such an extent that cracks do not occur due to excessive freezing, and moreover, the original shape of raw oyster shucked meat is fixed. In order to obtain such a frozen state, various experiments have been carried out, and it is preferable that only the surface layer of the outer skin of the peeled raw oyster is frozen, and that it is removed from the cryogen 3 such as low-temperature liquefied gas without freezing the inside. Therefore, the immersion time varies depending on the temperature of the cryogen 3 such as low-temperature liquefied gas used and the size of the object to be frozen, but it is approximately 10 seconds to 40 seconds, preferably 15 seconds to 30 seconds. It was hot.

The peeled raw oyster A' whose surface has been frozen in this way is maintained in this state, and one end is placed in the cryogen 3 such as low-temperature liquefied gas,
Each individual is placed in a separated state on a belt conveyor 5 which is inclined so that the other end is located outside the liquid, and is transported to the outside by a cryogen 3 such as low-temperature liquefied gas. Then, the surface-frozen shucked raw oysters A' are transported to a conventionally known refrigeration device 6 equipped with a mechanical refrigerator or a refrigeration system in which low-temperature liquefied gas such as liquid nitrogen is injected for cooling. Cool to a temperature of 25°C or lower, preferably -30°C or lower, and freeze completely. Note that the surface-frozen shelled raw oysters A' are placed on the belt conveyor 5 as described above when conveyed to this freezing device 6, but the raw oysters A' is surface-frozen in the above process and becomes soft. At the same time, the frozen surface layer is maintained in its unique shape, and its shape is not deformed by the load due to its own weight. 6
The frozen pieces are transported to the refrigerator, are completely frozen while maintaining this good shape, and are taken out from the freezing device 6 as individually separated so-called bulk frozen products.

Furthermore, the shucked oysters are completely frozen into pieces.
A'' transports this to the water tank 7, and the water tank 7
It is passed through water 8 stored at about 0° C. to perform a glaze treatment. As a result, a film of ice is formed on the surface of each of the completely frozen raw shucked oysters A'' after passing through the water 8, and each of the raw shucked oysters A'' is maintained in an individual state. The product is then commercialized as frozen product A, which is coated with an ice film.

Although the above embodiments have been explained by illustrating raw oyster shells, the present invention is not limited thereto, and can be effectively used as a method for individually freezing flexible substances such as shellfish shells. Of course.

As described above, the present invention allows peeled shellfish meat, which is flexible and easily deforms due to its own weight, to fall into the air and instantly become weightless, releasing the load due to its own weight and placing it in a low-temperature cryogen such as low-temperature liquefied gas. After immersing it in water and rapidly cooling it by direct contact to freeze the outer skin surface layer, it was completely frozen at -25℃ or less, and was further passed through water maintained at about 0℃ for glaze treatment, so that the load due to the above-mentioned own weight was The product is released, restored to its original state and fixed, and a frozen product that retains its natural state and is coated with an ice film is obtained, which significantly increases the commercial value of the product. The effect is extremely large.

[Brief explanation of drawings]

The drawing is a schematic diagram showing an example of an apparatus for carrying out the freezing method of the present invention. 1 and 7 are water tanks, 2 and 5 are belt conveyors, 3 is a cryogen, 4 is a cryogen storage tank, 6 is a freezing device, and 8 is water.

Claims (1)

[Claims] 1. Separate and drop the flexible shelled shellfish into a cryogen such as low-temperature liquefied gas, liquid cryogen, or snow-like dry ice, bring it into direct contact with the cryogen, and rapidly cool it. Only the outer skin surface layer of each peeled meat is frozen to fix the flexible appearance of the peeled meat, and then each solid is separated individually to a temperature below -25℃ using a freezing device with a cooling atmosphere. After being completely frozen, the shelled shellfish meat is made to pass through water maintained at approximately 0°C to maintain each solid body individually, and the surface is treated with a glaze. How to freeze.