RU2704442C1 - Method for production of leather semi-product of all types of freshwater fish - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: invention relates to fish-processing industry, namely to non-waste technology of processing secondary products of cutting freshwater fish to produce tanned leather semi-finished product. Method of producing a leather semi-product of all types of fres-hwater fish skins involves soaking fish skins in solution containing 4.5–5.0 wt% sodium chloride and 0.1 wt% antiseptic at temperature of 18–20 °C for 4.0–6.0 h, degreasing by treatment with 0.8–1.0 % soap solution for 1.5–2.0 hours at temperature of 37–40 °C and with periodic mixing. Then, removal of scales is performed by treatment with 0.2–0.5 % solution of protease enzyme preparation for 6.0–8.0 h at temperature of 37–40 °C and with periodic mixing, after that skins are thoroughly washed with cold water. Then one performs scouring, pickling by treating skins with solution containing 6 % glacial acetic acid and 3–3.5 % of food culinary salt to the solution weight for 8–12 hours at temperature of 18–20 °C, followed by tanning, fragrance , drying and storing the obtained semi-product.

EFFECT: proposed method for production of tanned semi-product of all types of freshwater fish skins allows to produce tanned semi-product of high quality, to realize non-waste technology of processing of secondary products of freshwater fish cutting, to rationally use leather raw material of fish industry, which is not in demand for technical purposes, reduced duration of technological process of production of tanned semi-product from skins of all types of freshwater fishes as compared to prototype from 66–54 hours to 41½–54 hours, enhance environmental friendliness of the process.

1 cl, 1 dwg, 3 ex

Description

The invention relates to the fish processing industry, and in particular to a non-waste technology for processing secondary products of cutting freshwater fish to obtain a tanned leather semi-finished product, which can be used as an additional source of natural raw materials in the manufacture of technical products.

A known method of producing fish skin comprising soaking raw materials, degreasing, waxing, washing, treatment with a solution of an enzyme preparation with a proteolytic effect, removing scales, tanning with a solution of chromium salts, neutralization, painting, oiling, drying and finishing [Patent No. 2026884. The method of obtaining fish skin / L.K. Petrichenko, - No. 2026884; Stated August 28, 1992; Publ. 01/20/1995].

The closest is a method of obtaining a tanned semi-finished product from the skins of all types of freshwater fish, in which the fish skins are soaked in a solution containing sodium chloride and antiseptic at a temperature of 18-20 ° C for 4.0-6.0 hours. Then they degrease by treating with 0.8-1.0% solution of the enzyme preparation Liporizin GZ for 1.5-2.0 hours at a temperature of 37-40 ° C and with periodic stirring. Fat-free skins of fish are treated with 0.3-0.6% solution of the enzyme preparation Protosubtilin GZh for 1.5-2.0 hours at a temperature of 37-40 ° C and with periodic stirring. Treated with Protosubtilin GCx fish skins are poured with a 0.3-0.6% solution of the enzyme preparation Collagenase and the treatment is carried out for 1.5-2.0 hours at a temperature of 37-40 ° C and with periodic stirring. After each enzymatic treatment, the fish skins are thoroughly washed with cold running water to remove residual enzymes. Scales are removed from the skins and coiled, and then pickling is carried out for 8-12 hours at a temperature of 18-20 ° C. Then the fish skins are tanned with a decoction of willow bark for 12-20 hours at a temperature of 18-20 ° C, fragrance, grease and drying.

The disadvantages of the known methods are: the complexity of the technology associated with the degreasing of raw materials with a detergent solution and subsequent washing in water to remove residual detergent; the use of a large concentration of the enzyme preparation with a proteolytic effect, which affects the cost of the finished product; the use of chromium oxide for tanning, which leads to wastewater contamination and worsening working conditions of production workers; insufficient specific action of enzyme preparations, as a result of which the duration and multi-stage process increases, additional operations on processing of raw materials, insufficiently high quality of leathers are required.

An object of the invention is the simplification and reduction of the technological cycle of production of leather semi-finished product, reducing the cost of the semi-finished product.

To solve the technical problem of the invention, a method for producing a leather semi-finished fish is proposed, characterized in that the fish skins are soaked in a solution containing 4.5-5.0 wt. % sodium chloride and 0.1 wt. % antiseptic at a temperature of 18-20 ° C for 4.0-6.0 hours, then the fish skins are degreased by treating with 0.8-1.0% soapy water for 1.5-2.0 hours at a temperature of 37- 40 ° C and periodic stirring, after degreasing, the skins are washed with running water and treated with a 0.2-0.5% solution of the enzyme preparation of the protease for 6.0-8.0 hours at a temperature of 37-40 ° C with periodic stirring in order to remove the scales, then the skins are rinsed with cold running water, after which they carry out meshes, pickling with a solution containing 6% ice acetic acid and 3-3.5% edible salt to the mass of the solution for 8-12 hours at a temperature of 18-20 ° C, tanning, perfume drying and storage. The technical result consists in improving the quality of the finished product, in expanding the functionality of the secondary raw materials obtained by cutting freshwater fish, implementing waste-free technology for the deep processing of secondary products, reducing the duration of the technological process for obtaining tanned semi-finished products from the skins of all types of freshwater fish, and increasing the environmental friendliness of the process through the use of vegetable tanning agent, an additional possibility of using wash water at each process operations, since they are enriched with hydrolysis products of biopolymers.

The figure 1 presents the technological scheme for obtaining a tanned semi-finished product from the skins of freshwater fish.

A method of obtaining a tanned semi-finished product from the skins of all types of freshwater fish is as follows.

The skins of all types of freshwater fish are soaked in a solution containing 4.5-5.0 wt. % sodium chloride and 0.1 wt. % antiseptic at a temperature of 18-20 ° C for 3.0-5.0 hours to remove mucus from the skin, contaminants, extract ballast globulin and albumin proteins, as well as to destroy microorganisms that accumulate on the surface of the raw material.

After soaking, the skins of fish for degreasing are immersed in a 0.8-1.0% soap solution pre-heated to a temperature of 37-40 ° C, the skins of fish are kept in this solution with periodic stirring for 1.5-2.0 hours, after The enzymatic treatment of fish skins is thoroughly washed with cold running water to remove residual soap solution.

Fat-free skins of all types of freshwater fish are dipped in a 0.2-0.5% solution of the enzyme preparation with protease activity, the fish skins are kept in this solution with periodic stirring for 6.0-8.0 hours, after enzymatic treatment, the fish skins are thoroughly washed with cold running water to remove residual enzyme. Due to its hydrolytic properties, when exposed to fish skin, protease weakens bonds that hold the scales in the cavities of the dermal layer of the skin, leads to weakening and partial breaking of bonds between protein substances, protein-lipid complexes, mucopolysaccharides are destroyed and removed from the skins, and protein formations of structureless substances are washed out. dermis.

When processing with a protease, a further weakening of the retention force of the scales occurs, and the skin acquires a smooth glossy surface.

After enzymatic processing, the technological process is carried out as follows: the skins are rinsed in water, the scales are removed and the coat is carried out. Coating can be done manually or automated.

The next step is pickling, which provides ductility, ductility and softness of the skin tissue. To do this, prepare a solution containing 6% glacial acetic acid and 3-3.5% edible salt to the mass of the solution. Pickling is carried out for 8-12 hours at a temperature of 18-20 ° C. The pickling process contributes to loosening the fibrous structure of the dermis, dehydrates the skin tissue and puts it in an “acidic state”, necessary for the next process of dressing - tanning.

Tanning is carried out in a decoction of willow bark, since it is an organic tanning agent that does not contain toxic substances, therefore, the process does not require pH adjustment with inorganic salts. As a result of the process of tanning, the skin becomes thicker, denser and as a result of the interaction of tannins of the tanning agent with the skin fibers, the latter acquires a rich brown color. 100 g of bark and willow twigs are pre-boiled for 30-40 minutes, cooled, filtered and sodium chloride is added to the broth in the amount of 30-40 g per 2 l of broth, the skins of fish are poured with this solution, tanning is carried out for 12-20 h at a temperature of 18-20 ° C.

Further processing is a fragrance, which is carried out in order to remove the specific smell of skins. The skins are immersed in a 1% solution of acetic acid with a temperature of 4-6 ° C for 5-6 hours.

The skins of all types of freshwater fish are dried at room temperature for 5-6 days. Drying is considered complete if the surface of the skins becomes dry, soft and gives a pull in all directions. The dried tanned semi-finished product from the skins of all types of freshwater fish is stored in warehouses at a temperature of not lower than 5 ° C and not higher than 25 ° C and relative humidity of 50-80%. Use a tanned semi-finished product for the production of elite haberdashery products.

A method of obtaining a tanned semi-finished product from the skins of all types of freshwater fish is illustrated by the following examples;

Example 1 (prototype).

A method of obtaining a tanned semi-finished product from the skins of all types of freshwater fish, characterized in that the fish skins are soaked in a solution containing 4.5-5.0 wt. % sodium chloride and 0.1 wt. % antiseptic, at a temperature of 18-20 ° C for 4.0-6.0 hours, then they are degreased by treatment with 0.8-1.0% solution of the enzyme preparation Liporizin GZh, the treatment is carried out for 1.5- 2.0 hours at a temperature of 37-40 ° C and with periodic stirring, fat-free skins of fish are treated with 0.3-0.6% solution of the enzyme preparation Protosubtilin GZx, processing is carried out for 1.5-2.0 hours at at a temperature of 37-40 ° C and with periodic stirring, the skins of fish treated with Protosubtilin GZx are poured with a 0.3-0.6% solution of the enzyme preparation Collagen s, the treatment is carried out for 1.5-2.0 hours at a temperature of 37-40 ° C and with periodic stirring, after each enzyme treatment the fish skins are thoroughly washed with cold running water to remove residual enzymes, after processing with Collagenase, the skin is removed from the skins and they carry out the smearing - removal of the muscle-fat layer and subcutaneous tissue, after which the skins are pickled by treating them with a solution containing 6% glacial acetic acid and 3.0-3.5% edible salt to the mass of the solution, the pickling process is carried out for 8-12 hours at a temperature of 18-20 ° C, then the fish skins are tanned, which is a decoction of willow bark, and the bark and willow twigs in an amount of 100 g are pre-boiled for 30-40 minutes, cooled, filtered and introduced into it sodium chloride in an amount of 30-40 g per 2 l of broth, fish skins are poured with this solution, tanning is carried out for 12-20 hours at a temperature of 18-20 ° C, after tanning, perfume is carried out to remove the specific smell of skins, the perfume process is carried out 1% solution of acetic acid at a temperature of 4-6 ° C for 5-6 hours, after perfumes carry out the fatliquoring of fish skins with castor oil and ammonia, taken at a volume ratio of castor oil and ammonia equal to 4: 1, the process is conducted at a temperature of 37-40 ° C for 8-12 hours, then the fish skins are dried at room temperature in within 5-6 days until the skin surface reaches dryness, softness and stretch in all directions.

Example 2

Take 1 kg of carps of silver carp is subjected to soaking in a solution containing 4.5 wt. % sodium chloride and 0.1 wt. % antiseptic at a temperature of 18 ° C for 3.0 hours to remove mucus from the surface of the skins, contaminants, extract ballast globulin and albumin proteins, as well as to destroy microorganisms that accumulate on the surface of the raw material.

After soaking, the fish skins for degreasing are immersed in a 0.8% soap solution to a temperature of 37 ° C, the fish skins are kept in this solution with periodic stirring for 1.5 hours, after enzymatic treatment, the fish skins are thoroughly washed with cold running water to remove residues enzyme.

Fat-free skins of all types of freshwater fish are dipped in a 0.2% solution of enzyme preparation with protease activity, the fish skins are kept in this solution with periodic stirring for 6.0 hours, after enzymatic treatment, the fish skins are thoroughly washed with cold running water. Due to its hydrolytic properties, when exposed to fish skin, protease weakens bonds that hold the scales in the cavities of the dermal layer of the skin, leads to weakening and partial breaking of bonds between protein substances, protein-lipid complexes, mucopolysaccharides are destroyed and removed from the skins, and protein formations of structureless substances are washed out. dermis.

After enzymatic treatment, the fish skins are thoroughly washed with cold running water to remove residual enzyme. Protease treatment softens connective tissue proteins present in the skin. When processing with this enzyme preparation, ballast accompanying proteins are additionally removed due to hydrolysis, since it has not only lipolytic, but also proteolytic activity. When processing an enzyme preparation, a further weakening of the retention force of the scales occurs, and the skin acquires a smooth glossy surface. After enzymatic processing, the technological process is carried out as follows: the skins are rinsed in water, the scales are removed and the coat is carried out. Healing can be done manually.

The next step is pickling, which provides ductility, ductility and softness of the skin tissue. To do this, prepare a solution containing 6% glacial acetic acid and 3% edible table salt by weight of the solution. Pickling is carried out for 9 hours at a temperature of 18 ° C. The pickling process contributes to loosening the fibrous structure of the dermis, dehydrates the skin tissue and puts it in an “acidic state”, necessary for the next process of dressing - tanning.

Tanning is carried out in a decoction of willow bark, as this is an organic tanning agent that does not contain toxic substances. As a result of the process of tanning, the skin becomes thicker, denser and as a result of the interaction of tannins of the tanning agent with the skin fibers, the latter acquires a rich brown color. 100 g of bark and willow twigs are pre-boiled for 30 minutes, cooled, filtered, and sodium chloride is added to the broth in the amount of 30 g per 2 l of broth, the skins of fish are poured with this solution, tanning is carried out for 12 hours at a temperature of 18 ° С .

Further processing is a fragrance, which is carried out in order to remove the specific smell of skins. The skins are immersed in a 1% solution of acetic acid at 4 ° C for 5 hours.

The skins of all types of freshwater fish are dried at room temperature for 5 days. Drying is considered complete if the surface of the skins becomes dry, soft and gives a pull in all directions. The dried tanned semi-finished product from the skins of all types of freshwater fish is stored in warehouses at a temperature not lower than 5 ° C and not higher than 25 ° C and a relative humidity of 50%. Use a tanned semi-finished product for the production of elite haberdashery products.

Example 3

The skins of all types of freshwater fish are soaked in a solution containing 5.0 wt. % sodium chloride and 0.1 wt. % antiseptic at a temperature of 20 ° C for 5.0 hours to remove mucus from the skin, contaminants, extract ballast globulin and albumin proteins, as well as to destroy microorganisms that accumulate on the surface of raw materials.

After soaking, the fish skins for degreasing are immersed in a 1.0% soap solution pre-heated to a temperature of 40 ° C, the fish skins are kept in this solution with periodic stirring for 2.0 hours, after enzymatic treatment, the fish skins are thoroughly washed with cold running water to Removing residues of soapy water.

Fat-free skins of all types of freshwater fish are dipped in a 0.5% solution of the enzyme preparation with protease activity, the fish skins are kept in this solution with periodic stirring for 8.0 hours, after enzymatic treatment, the fish skins are thoroughly washed with cold running water to remove residual enzyme. Due to its hydrolytic properties, when exposed to fish skin, protease weakens bonds that hold the scales in the cavities of the dermal layer of the skin, leads to weakening and partial breaking of bonds between protein substances, protein-lipid complexes, mucopolysaccharides are destroyed and removed from the skins, and protein formations of structureless substances are washed out. dermis.

After enzymatic treatment, the technological process is carried out as follows: the skins are rinsed in water, the scales are removed and the coiling is performed. Coating can be performed manually or automated.

The next step is pickling, which provides ductility, ductility and softness of the skin tissue. To do this, prepare a solution containing 6% glacial acetic acid and 3.5% edible table salt by weight of the solution. Pickling is carried out for 11 hours at a temperature of 20 ° C. The pickling process contributes to loosening the fibrous structure of the dermis, dehydrates the skin tissue and puts it in an “acidic state”, necessary for the next process of dressing - tanning.

Tanning is carried out in a decoction of willow bark, since it is an organic tanning agent that does not contain toxic substances, therefore, the process does not require pH adjustment with inorganic salts. As a result of the process of tanning, the skin becomes thicker, denser and as a result of the interaction of tannins of the tanning agent with the skin fibers, the latter acquires a rich brown color. 100 g of bark and willow twigs are pre-boiled for 40 minutes, cooled, filtered and sodium chloride is added to the broth in the amount of 40 g per 2 l of broth, fish skins are poured with this solution, tanning is carried out for 20 hours at a temperature of 20 ° С .

Further processing is a fragrance, which is carried out in order to remove the specific smell of skins. The skins are immersed in a 1% solution of acetic acid at 6 ° C for 6 hours.

The skins of all types of freshwater fish are dried at room temperature for 6 days. Drying is considered complete if the surface of the skins becomes dry, soft and gives a pull in all directions. The dried tanned semi-finished product from the skins of all types of freshwater fish is stored in warehouses at a temperature not lower than 5 ° C and not higher than 25 ° C and a relative humidity of 80%. Use a tanned semi-finished product for the production of elite haberdashery products.

The proposed method for obtaining tanned semi-finished products from the skins of all types of freshwater fish allows:

- get a tanned semi-finished product from the skins of all types of freshwater fish of higher quality in comparison with the prototype;

- implement a non-waste technology for processing secondary products of cutting freshwater fish;

- rational use of low-demand for technical purposes leather raw materials of the fishing industry;

- reduce the duration of the technological process of obtaining tanned semi-finished products from the skins of all types of freshwater fish compared with the prototype from 66-54 hours to 41.5-54 hours;

- increase the environmental friendliness of the process through the use of vegetable tanning agent;

- use wash water for each technological operation enriched with hydrolysis products of biopolymers.

Claims (1)

A method of obtaining a leather semi-finished fish product, characterized in that the fish skins are soaked in a solution containing 4.5-5.0 wt.% Sodium chloride and 0.1 wt.% Antiseptic, at a temperature of 18-20 ° C for 4, 0-6.0 h, then the fish skins are degreased by treating with 0.8-1.0% soapy water for 1.5-2.0 h at a temperature of 37-40 ° C and periodic stirring, after degreasing the skins are washed with running water and carry out the processing of 0.2-0.5% solution of the enzyme preparation of the protease for 6.0-8.0 hours at a temperature of 37-40 ° C with periodic stirring In order to remove the scales, then the skins are rinsed with cold running water, after which they mend, pickle with a solution containing 6% glacial acetic acid and 3-3.5% edible salt to the mass of the solution for 8-12 hours at a temperature 18-20 ° C, tanning, fragrance, drying and storage.

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