JP2006180744A - Method for cleaning fishskin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning fishskin by which foreign matters such as fat, sludge, scales and the like are efficiently removed while maintaining the shape of the fishskin to obtain such fishskin as to be excellent in its appearance, color tone, flavor and storage stability, and be usable as food material and also as leather raw material or the like. <P>SOLUTION: The method for cleaning fishskin comprises the following process: a salt-water cleaning process of cleaning the fishskin with hot water in which neutral salt is dissolved; and a dehydration process of dehydrating the fishskin. The neutral salt preferably comprises natrium chloride. The salt-water cleaning process is preferably performed at 15-30°C, and preferably comprises a process of repeating salt-water cleaning and dehydration more than once. The water-cleaning process of cleaning the fishskin with water is performed after the salt-water cleaning process, and it is preferable that the dehydration process is performed after the water-cleaning process. The water-cleaning process preferably comprises a process of repeating water-cleaning and dehydration more than once. The hydration process preferably comprises centrifugal dehydration. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for cleaning fish skin that can be used as a raw material for food and leather.

  Until now, most of the fish skin (fish skin) discharged as a by-product when processing fish has been discarded as waste or used as cheap meal materials and fertilizer materials. Has become an important issue.

  Fish skin contains abundant proteins, mainly collagen, and is being used as a raw material for proteins. Lipids contained in fish skin, scales and sludge adhering to the surface of fish skin, etc. Such visual stains adversely affect the quality of the final product, such as appearance, color, odor, storage stability, etc., and reduce the value of the product.

  When using fish skin as a food raw material, it is common to wash the fish skin with seawater or tap water to wash away tangible solids. For example, in Patent Document 1 below, fish skin is used as a raw material. , A salt mixing process in which salts are mixed to degrease and deodorize the raw material and kept at a low temperature, a salt removing process in which the salt is removed from the raw material mixed with the salt, and a collagen is extracted from the raw material from which the salt has been removed A collagen extraction step, a fish collagen extracted from this collagen extraction step, a filtration step for decolorizing and deodorizing, and a drying step for drying the fish collagen treated in this filtration step A method for producing a fish collagen is disclosed.

  In Patent Document 2 below, fish skin is washed with 0.1 to 5% saline and fresh water, extracted with neutral water at a temperature of 50 to 100 ° C., the aqueous layer is subjected to enzyme treatment, and concentrated. Then, a method for producing a gelatin peptide which is treated with activated carbon and dried is disclosed.

In Patent Document 3 below, a step of insolubilizing a skin layer of fish skin and a portion of the dermis layer containing pigment cells on the epidermis layer side, and at least a part of the dermis layer that has not been insolubilized are swollen. A method for producing collagen is disclosed which includes a step and a step of recovering a swollen dermis layer.
Japanese Patent No. 2931814 JP 2004-141007 A JP 2004-269478 A

  However, for example, in the method described in Patent Document 1, it is necessary to keep cold at a low temperature for a long period of time using salts. As a result, there were problems in terms of odor and storage stability.

  In addition, lipids could not be sufficiently removed even by washing with saline and fresh water described in Patent Document 2 or with purified water described in Patent Document 3. Furthermore, there has been a problem that the cost is very high when cleaning is performed using an organic solvent.

  Therefore, in order to use fish skin that has been washed as described above as a raw material for extraction of extract components or other food raw materials, reprocessing such as a lipid removal step or a turbidity removal step is required. However, it could only be used for products with relatively short products and products that did not place the highest priority on the flavor of the material. Moreover, in the conventional method, only a low value as a leather raw material could be obtained.

  Therefore, the object of the present invention is to effectively remove contaminants such as lipids, sludge, scales, etc. from the fish skin while maintaining the shape of the fish skin, and the appearance of the obtained fish skin, An object of the present invention is to provide a method for cleaning fish skin that is excellent in color, flavor and storage stability and can be used not only as a raw material for foods but also as a raw material for leather materials.

  In order to achieve the above object, the method for washing fish skin of the present invention includes a salt water washing step for washing fish skin using warm water in which a neutral salt is dissolved, and a dehydration step for dehydrating the washed fish skin. It is characterized by that.

  According to the washing method of the present invention, the fish skin is washed with warm water in which a neutral salt is dissolved, whereby the fish skin can be sufficiently swollen and lipids and sludge can be efficiently separated. In the dehydration step, lipids and sludge remaining in the fish skin can be easily removed together with excess moisture.

  In the present invention, sodium chloride is preferably used as the neutral salt. According to this, the processing cost is low, the safety is high, and a fish skin suitable for food use can be obtained.

  Moreover, it is preferable to perform the said salt-water washing process at 15-30 degreeC. According to this, lipid, scale, sludge, etc. can be efficiently removed while maintaining the fish skin shape.

  Moreover, it is preferable that the said salt water washing | cleaning process consists of a process which repeats salt water washing | cleaning and dehydration several times. According to this, the washing effect by salt water can be heightened.

  Moreover, it is preferable to perform the water washing process which wash | cleans a fish skin after the said salt water washing process, and then performs the said dehydration process. According to this, the salt remaining in the fish skin can be removed and the cleaning effect can be enhanced.

  Furthermore, it is preferable that the said water washing process consists of a process which repeats water washing and dehydration several times. According to this, the cleaning effect by water washing can be heightened.

  Furthermore, it is preferable to perform centrifugal dehydration in the dehydration step. According to this, lipid, sludge, etc. remaining in the fish skin can be easily and efficiently removed together with excess moisture.

  Furthermore, as the fish skin used in the present invention, it is preferable to use a flounder or cod fish skin.

  According to the present invention, it is possible to efficiently remove the contaminants such as lipids, sludge and scales in the fish skin while maintaining the shape of the fish skin, so that the appearance, color tone, flavor and storage stability are excellent. The fish skin can be obtained efficiently.

  The fish skin used in the present invention is not particularly limited in terms of its origin, and examples include fish skin such as cod, flounder, salmon, trout, cormorant, shark, ray, tilapia, etc. The fish skins of cod such as cod, komai, and walleye pollock, or flounder such as flounder, grasshopper, halibut, flounder are preferably used.

Hereinafter, the fish skin cleaning method of the present invention will be described.
(1) Salt water washing | cleaning process First, the fish skin which removed the bone and the body is immersed in the warm water which melt | dissolved the neutral salt. In addition, you may stir to such an extent that a fish skin shape can be maintained during immersion.

  The neutral salt referred to in the present invention means a salt exhibiting pH 6 to 8 in an aqueous solution, specifically, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, potassium sulfate, calcium sulfate, Although magnesium sulfate etc. can be illustrated, in this invention, it is preferable to use sodium chloride from the surface of the safety | security at the time of applying to a foodstuff, or availability.

  Moreover, it is preferable that the density | concentration of a neutral salt is 0.1-10 mass% from the point of the washing | cleaning effect, More preferably, it is 2.5-7.5 mass%, Most preferably, it is 4-6. % By mass. When the concentration of the neutral salt is outside the above range, a sufficient cleaning effect cannot be obtained, and particularly when the concentration of the neutral salt is too high, the neutral salt is wasted, which is not preferable.

  The temperature of warm water in which the neutral salt is dissolved (hereinafter also referred to as salt water) is preferably 15 to 30 ° C., more preferably 20 to 28 ° C., from the viewpoint of the cleaning effect. When the temperature of the salt water is lower than the above range, a sufficient cleaning effect cannot be obtained, and when it is higher than the above range, the protein mainly composed of collagen contained in the fish skin is dissolved, and the shape of the fish skin is This is not preferable because it cannot be maintained and causes workability and yield.

  In addition, the immersion time may be set so that the fish skin can be sufficiently swollen to separate the lipid, but it may be about 0.5 to 6 hours in consideration of work efficiency.

  The ratio of fish skin to salt water varies depending on the fish skin origin, water content, etc., but it is sufficient that the fish skin is completely immersed. What is necessary is just to immerse 5-50 mass%.

  In the salt water washing step, salt water washing and dehydration may be repeated a plurality of times (preferably 1 to 5 times). According to this, lipid, dirt, etc. can be removed efficiently. Dehydration can be performed by a method such as centrifugal dehydration, pressing, screw pressing, or the like. For example, when centrifugal dehydration is performed, it is preferably performed at 500 to 3000 rpm for 1 to 15 minutes.

(2) Water washing step In the present invention, it is preferable to provide a water washing step after the salt water washing step (after being subjected to dehydration, but may be in a state where it has not been dehydrated). Thereby, the cleaning effect can be further enhanced.

  Specifically, the fish skin recovered from the salt water or the dehydrated fish skin may be dispersed in 2 to 20 times the amount of fish skin mass and washed with water. The temperature of the water used for washing should just be 30 degrees C or less, and 15-30 degrees C is preferable.

  In the water washing step, water washing and dehydration may be repeated a plurality of times (preferably 1 to 5 times). Dehydration can be performed by the same method as described above.

(3) Dehydration step In any case, in the present invention, a dehydration step is finally performed to remove excess water as much as possible.

  The fish skin obtained by the above method is subjected to a water washing step as necessary after the salt water washing step, and at least finally through a dehydration step, lipids, sludge, scales are efficiently removed, and the appearance, color tone , Flavor and storage stability. Therefore, the obtained fish skin can be used not only for processing foods and leather products in a wet state but also dried and distributed as it is.

(1) Confirmation of optimum conditions of neutral salt concentration A predetermined amount of sodium chloride was completely dissolved in 600 ml of water to prepare a salt water having a sodium chloride concentration of 0 to 10% by mass. Then, 300 g of flounder fish skin (wet state) produced from the fillet processing plant was dispersed and immersed in these salt waters, and the amount of water absorbed into the fish skin and the degree of salt water contamination (OD660) were examined. The result is shown in FIG.

  From FIG. 1, it can be seen that the fish skin swells and the contaminants are removed with a peak when the sodium chloride concentration of the salt water is 5 mass%.

(2) Confirmation of optimum conditions of washing temperature 11 g of sodium chloride was dissolved in 200 ml of water to prepare brine, and 100 g of unwashed flounder skin that had been dehydrated in advance was immersed therein. At this time, the temperature of salt water was examined under various conditions.

  After immersing the fish skin in salt water at each temperature for 2 hours, the fish skin is taken out, washed 6 times with 700 ml of water, then dehydrated by centrifugation, and the lipid content in the fish skin (in terms of dry matter) is determined. It was measured. The result is shown in FIG. In FIG. 2, “weight” means the dry matter weight of the fish skin, and “lipid” means the lipid content in the fish skin dry matter.

  FIG. 2 shows that the lipid content per dried product tends to decrease as the immersion temperature of the salt water increases. This is thought to be because the fish skin softens as the temperature of the salt water rises and lipids are easily separated. However, when the temperature of the salt water was 30 ° C. or higher, the shape of the fish skin collapsed, making recovery difficult. Therefore, it was found that the temperature during the immersion treatment in salt water is preferably 15 to 30 ° C., and 25 ° C. is optimal in the case of flounder skin.

  Dissolve 32 g of sodium chloride completely in 600 ml of water to prepare salt water (25 ° C.), disperse and immerse 300 g of flatfish fish skin (wet state) produced from the fillet processing plant, and after 2 hours, sieve the fish skin Parts were collected.

  The recovered fish skin was dispersed in 600 ml of water and washed with water, followed by centrifugal dehydration (1000 rpm, 5 minutes). Furthermore, the same water washing and dehydration were performed three times to obtain fish skin. When the lipid content in the fish skin was measured, the lipid content per dry solid was 0.6% by mass. In addition, the lipid content per dry solid in the unwashed fish skin used was 2.5% by mass.

  On the other hand, as a control, only the water washing and dehydration were performed 6 times without using the salt water to obtain a fish skin. The lipid content in the fish skin was measured and found to be 1.4% by mass per dry solid. Further, when the dehydration step was not performed at this time, the lipid content per dry solid was 2.4%.

  From the above results, it was confirmed that the lipid content in the fish skin can be efficiently removed by combining the salt water washing step, the water washing step, and the dehydration step. It was also confirmed that visual dirt such as sludge and scale can be efficiently removed.

  In the method for cleaning fish skin of the present invention, it is possible to effectively remove the contaminants such as lipids, sludge, and scales of the fish skin while maintaining the shape of the fish skin, so that the appearance, color, flavor, and preservation are preserved. It is possible to efficiently obtain a fish skin having excellent stability. Therefore, the obtained fish skin can be used for food materials such as gelatin and collagen, extraction raw materials for extract seasonings, processed food materials such as delicacy, raw materials such as pet food, and other leather raw materials.

It is a figure which shows the relationship between the sodium chloride density | concentration in a salt water washing | cleaning process, the amount of water absorption to a fish skin, and salt water pollution degree (OD660). It is a figure which shows the relationship between the warm water temperature in a salt-water washing process, and the lipid content in the fish skin after washing | cleaning.

Claims (8)

  2. A method for washing fish skin, comprising: a salt water washing step for washing fish skin using warm water in which a neutral salt is dissolved; and a dehydration step for dehydrating the washed fish skin.   The method for washing fish skin according to claim 1, wherein sodium chloride is used as the neutral salt.   The method for washing fish skin according to claim 1 or 2, wherein the salt water washing step is performed at 15 to 30 ° C.   The said salt water washing | cleaning process is a washing method of the fish skin as described in any one of Claims 1-3 which consists of the process of repeating salt water washing | cleaning and dehydration in multiple times.   The method for washing fish skin according to any one of claims 1 to 4, wherein after the salt water washing step, a water washing step for washing the fish skin is performed, and then the dehydration step is performed.   6. The method for washing fish skin according to claim 5, wherein the water washing step comprises a step of repeating water washing and dehydration a plurality of times.   The method for washing fish skin according to any one of claims 1 to 6, wherein centrifugal dehydration is performed in the dehydration step.   The fish skin washing method according to any one of claims 1 to 7, wherein a fish skin of flounder or cod is used as the fish skin.

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