Electricity-independent ice preservation and low-temperature preservation of seafood using coniferous tree-derived sawdust.

Abstract

The invention provides a means to delay the melting of ice used on board a ship and maintain the freshness of seafood without using electricity or refrigeration equipment. [Solution] The present invention involves placing sawdust 3 derived from coniferous trees as an insulating material on the bottom 2a, sides 2b, and top 2c of a polystyrene foam container, and containing only ice inside. This configuration delays the melting of ice used on board a ship and enables low-temperature maintenance without the use of electric or mechanical cooling devices. The stored ice is then placed in a livewell on board the ship to lower the water temperature inside the livewell.

Description

Technical Field

[0001] The present invention relates to aquatic product circulation and freshness preservation technology, and particularly to low-temperature preservation applications for delaying ice melting without using electricity.

Background Art

[0002] In the equatorial or tropical regions, the outside air temperature is high, and the ice loaded on fishing boats is likely to melt in a short period. Therefore, it is difficult to control the water temperature in the on-board fish baskets, and the deterioration of the quality of aquatic products has become a problem.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to provide a means for delaying the melting of ice used on board and maintaining the freshness of aquatic products without using electricity or refrigeration equipment.

Means for Solving the Problems

[0004] In the present invention, as a preferred example, sawdust derived from coniferous trees is arranged on the bottom, side, and top surfaces of a styrofoam container with a thickness of 30 to 50 cm. Only ice is contained inside. The stored ice is put into the on-board fish basket to lower the water temperature.

Effects of the Invention

[0005] According to the present invention, without using electricity or a mechanical cooling device, with an ice storage structure using sawdust derived from coniferous trees, under fishing conditions where usually 40 kg of ice is used in about 3 days, the same amount of ice can be used for fish basket cooling over about 4 days, and the export quality of aquatic products can be maintained.

Brief Description of the Drawings

[0006] [Figure 1]This is a cross-sectional view showing the structure of an insulated container for storing ice, which is constructed by laying sawdust (3) on the bottom surface (2a) of a polystyrene foam container body (1a), placing ice (4) on top of the sawdust (3), filling the sides (2b) and top surface (2c) of the container body (1a) with sawdust (3), and covering it with a container lid (1b). [Figure 2] Figure 1 is a schematic diagram illustrating the process and usage state in which ice (4) stored in an insulated container for ice preservation is put into a fish farm (6) installed inside a fishing vessel (5), and the seawater (7) inside the fish farm (6) is cooled, thereby maintaining a low temperature for the marine products, particularly marine products (8) including tuna, contained in the fish farm (6). [Modes for carrying out the invention]

[0007] The embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. The low-temperature preservation application of the present invention aims to delay the melting of ice (4) used on board ships in fisheries in equatorial or tropical regions without the use of electric or mechanical cooling equipment.

[0008] In this invention, as shown in Figure 1, sawdust (3) is placed as an insulating layer on the bottom surface (2a) and sides (2b) of the polystyrene foam container body (1a), and on the top surface (2c) of the polystyrene foam container lid (1b) that is placed over it. The sawdust (3) is derived from trees belonging to the coniferous tree family, and is preferably derived from Japanese cedar (Cryptomeria japonica) or Japanese cypress (Chamaecyparis obtusa).

[0009] The sawdust (3) is a material that contains many voids due to its fibrous structure and has humidity control properties that allow it to repeatedly absorb and release moisture. In addition, it has antibacterial properties derived from essential oil components, which helps maintain the hygiene of the storage environment for ice (4).

[0010] The sawdust (3) is thought to have the effect of suppressing heat transfer from the outside by forming an air layer due to its many voids. Furthermore, due to its humidity control properties, it is thought that moisture generated during the melting process of the ice (4) is retained, and the temperature change around the ice (4) is mitigated. As a result of these effects, the melting rate of the ice (4) is reduced, and it is maintained in a state that is usable for cooling purposes.

[0011] The thickness of the sawdust (3) is preferably 30 to 50 cm on the bottom (2a) and sides (2b) of the polystyrene foam container body (1a), and on the top surface (2c) of the polystyrene foam container lid (1b), thereby effectively reducing the melting rate of the ice (4) contained inside the container.

[0012] Only ice (4) is contained inside the polystyrene foam container body (1a). The sawdust (3) may be in direct contact with the ice (4), but it is not intended to be in direct contact with the marine products (8) or the fish bodies. In typical fish tank cooling applications, cooling is performed indirectly via the ice (4).

[0013] As shown in Figure 2, the ice (4) preserved by the present invention is placed in a fish farm (6) installed on a fishing vessel (5) and functions as a secondary cooling medium that lowers the temperature of the seawater (7) inside the fish farm (6). This suppresses the rise in body temperature of the marine products (8) contained in the fish farm (6), especially tuna, and maintains their freshness. [Examples] The following describes specific embodiments of the present invention, but the present invention is not limited to these.

[0014] Example 1 (Ice storage on board ships in Indonesia) A polystyrene foam container, consisting of a polystyrene foam container body (1a) and a polystyrene foam container lid (1b), was mounted on a small fishing vessel (5) operating in the waters off Indonesia. A layer of sawdust (3) derived from Japanese cedar (3) was placed approximately 40 cm thick as an insulating layer on the bottom (2a), sides (2b), and top (2c) of the container, and only ice (4) was placed inside.

[0015] When the state of the ice (4) in the container was observed in an environment where the outside temperature was 30°C or higher, it was confirmed that, while in conventional methods where sawdust was not used, the ice would become unusable for cooling the fish pens after about 3 days of fishing, in this embodiment, the ice (4) remained usable for cooling the fish pens for about 4 days of fishing.

[0016] Example 2 (Preserving tuna freshness by cooling the fish tank) In Example 1, the preserved ice (4) was placed in a fish farm (6) installed on a fishing boat (5) to lower the temperature of the seawater (7) inside the fish farm (6). Subsequently, marine products (8), including tuna, were placed inside the fish farm (6).

[0017] As a result, the water temperature in the holding tanks (6) was stably maintained at a low temperature, suppressing the rise in body temperature of the marine products (8), especially the tuna. This allowed the catch, which had previously been intended for local consumption, to be evaluated as meeting the quality standards for overseas export.

[0018] Example 3 (Application of cypress-derived sawdust) In the same configuration as in Example 1, when we conducted tests using sawdust (3) derived from Japanese cypress (Chamaecyparis obtusa), we confirmed that it had the same effect as the sawdust (3) derived from Japanese cedar, delaying the melting of ice (4) and cooling the fish pond (6). On the other hand, when we used sawdust derived from hardwoods from southern Japan, we could not obtain a sufficient effect of delaying the melting of ice (4).

[0019] From the above examples, it has been confirmed that, according to the present invention, the melting of ice (4) used on board a ship can be delayed without using electricity or mechanical cooling equipment, and the freshness of marine products (8), especially tuna, can be maintained through the cooling of the fish pen (6). [Industrial applicability]

[0020] The present invention can improve the fishing operation that has conventionally returned to the fishing port due to the melting of ice by extending the usable period of ice used on board in the fishery in the equatorial or tropical regions. This makes it possible to continue fishing activities while reducing the number of voyages of fishing vessels, and as a result, an increase in the catch and a reduction in fuel consumption can be achieved. The present invention is widely applicable industrially as a low-cost and highly practical freshness retention technology in the fishery industry including small-scale fishermen.

Explanation of Signs

[0021] 1a Foamed styrene container body 1b Foamed styrene container lid 2a Bottom surface 2b Side surface 2c Top surface 3 Sawdust 4 Ice 5 Fishing vessel 6 Fish basket 7 Seawater in the fish basket 8 Fishery product (tuna)

Claims

1. An electric-independent low-temperature retention application characterized by placing sawdust derived from coniferous trees around ice used in aquatic fisheries in equatorial or tropical regions to significantly delay the melting of the ice and maintain it in a state suitable for use as a fish pen cooling application.

2. The low-temperature storage application according to claim 1, wherein the coniferous tree is Japanese cedar (Cryptomeria japonica) or Japanese cedar (Chamaecyparis obtusa).

3. The low-temperature holding application according to claim 1 or 2, wherein the sawdust is a coniferous tree-derived material having at least one of the following properties.

1. High air content due to fiber structure 2. Humidity control characteristics involving repeated absorption and release of moisture.

3. Antibacterial properties derived from essential oil components 4. Lower thermal conductivity than hardwood-derived materials.

4. The low-temperature storage application according to any one of claims 1 to 3, wherein sawdust derived from hardwoods is excluded.

5. The low-temperature storage application according to any one of claims 1 to 4, wherein the sawdust is arranged on the bottom, sides, and top of a polystyrene foam container to a thickness sufficient to significantly delay the melting of the ice, preferably to a thickness of 30 to 50 cm, and only ice is contained in the container.

6. The low-temperature preservation application according to any one of claims 1 to 5, wherein the ice preserved by the above application is put into a fish farm installed on a ship to lower the water temperature inside the fish farm, and in a normal usage mode, the sawdust does not intentionally come into direct contact with the fishery products, thereby indirectly preserving the fishery products at a low temperature.

7. The low-temperature storage application according to claim 6, wherein the aquatic product is tuna.

8. The low-temperature preservation application according to any one of claims 1 to 7, which allows 40 kg of ice, which is normally used for about 3 days, to be used for cooling fish tanks for a longer period, thereby maintaining the export quality of marine products.

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