RU2468072C1 - Fish liver oil production method - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention relates to food industry, in particular, to fish liver oil production method. The fish liver oil production method involves raw material defrosting to a temperature equal to -1 - -5°C and milling into particles sized 2-5 mm. Then the produced product is exposed to ultrasound treatment at 22-44 kHz, while continuously stirred. The treatment duration is equal to 5-30 minutes. The milled raw material layer height in the vessel is equal to 2.5-12 cm. Treatment is performed via a 10-30°C water medium. The distance between the radiator and the vessel bottom is equal to no less than 1 cm. Then the mass is delivered for centrifugation and separation to separate fat from grax.

EFFECT: method allows to intensify the fat extraction process, increase fat yield as well as to manufacture a product of high quality and biological value, stable during storage.

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Description

The invention relates to the fishing industry, and in particular to a method for producing fat from fish liver.

A known method of producing fish oil, including grinding the raw material in a spinning top, adding hydrochloric acid with stirring in the ratio of acid and fish 0.5-1.0: 100 and a temperature of 15 to 40 ° C until the pH of the medium reaches 4.5-5, 5 for 30-120 minutes. The resulting suspension is centrifuged on a three-phase super-decanter to isolate the lipid, dense and liquid fractions, after which the lipoprotein fraction is sent for separation, refined, cooled to a temperature of 0 to 15 ° C and kept at this temperature for 5-20 hours until the saturated fraction crystallizes completely lipids. Uncrystallized unsaturated lipids were separated by suction filtration for 1-6 hours to obtain edible fish oil. The resulting fish oil is stabilized with tocopherol in an amount of 0.5-1% (RF Patent No. 2039793 C1, CL 6 C11B 1/10, 1990).

The disadvantage of this method is that the accumulation of toxic substances in fish oil is possible.

A known method of producing fish oil, including grinding shark liver on a top, adding honey during stirring at a ratio of honey and crushed raw materials 1: 1 for 60 minutes at room temperature. The resulting suspension is centrifuged, the lipoprotein fraction is separated, propolis is added to it as a preservative in the amount of 5-30% by weight of the final product. The resulting fat is cooled to a temperature of at least 2 ° C and stored frozen (RF Patent No. 2202253, CL 7 A23L 1/325, C11B 1/00).

The disadvantage of this method is the formation of microorganisms, the development of which leads to spoilage of the product and the deterioration of the properties of the resulting fat. In addition, this method is provided for the production of fat from shark liver, where the content of organochlorine pesticides is increased, therefore, without special purification, it is impossible to obtain edible fat with improved quality and safety indicators.

A known method of producing fat in the production of fish meal using electroplasmolysis, including the same basic technological steps as the traditional one, but characterized in that to increase the fat yield and the quality of the target product - flour, crushed raw materials before heat treatment is mixed with water until homogeneous mass in the amount of 8-15% of the mass of raw materials (3) and subjected to processing in an electric field by exposure to an alternating electric field to a temperature of the onset of coagulation of protein substances 32-35 ° C, lovuyu treatment is carried out at a lower temperature (60-75 ° C). (see USSR author's certificate 1683642 A23K 1/10 1991).

However, in this method, the effect of an electric field on a homogeneous aquatic fish mass is combined with electrical processing. This method does not take into account the influence of the electric field during heat treatment on the fat yield, and most importantly the composition of fatty acids, in particular the content of physiologically active highly unsaturated ω3 (eicosapentaenoic - 20: 5 and docosahexaenoic - 22: 6).

Closest to the claimed method is a method of extracting fat from the liver of fish, including thawing raw materials, grinding and processing by exposure to electric current (see USSR author's certificate 1521753 С11В 13/00 1989).

The disadvantage of this method is the low yield of fat, partial oxidation due to the fact that the fat is moistened before processing.

The technical task of the claimed technical solution is to intensify the extraction of fat, increase the yield of fat and increase its quality and biological value.

The problem is solved in a method of obtaining fat from fish liver, including thawing raw materials, grinding and processing by physical action, while thawing is carried out to a temperature of minus 1 - minus 5 ° C, crushed to a particle size of 2-5 mm, and as a physical impact using ultrasound with a frequency of 22-44 kHz, the duration of the processing of crushed raw materials in the tank with a layer height of 2.5-12 cm with constant stirring is 5-30 minutes, and the effect is through an aqueous medium with a temperature of 10-30 ° C and Russ at least 1 cm between the emitter and the bottom of the tank, at the end of the treatment, the mass is sent to centrifugation and separation to separate the fat from the graks.

The most common way to get fat from the liver of fish is high-temperature warming, while the warming process can reach 180 minutes. Such heating of fat with the access of air leads to its oxidation, while the value of peroxide and acid numbers increases. Thus, the biological value of the resulting fat is reduced, since oxidation leads to the destruction of polyunsaturated fatty acids and fat-soluble vitamin A. Therefore, to accelerate the extraction process and obtain the target product with improved quality and biological value, the claimed method of producing fat from fish liver with the proposed modes and receptions.

The process of extracting fat from biological material (fish liver) under the action of ultrasound corresponds to existing ideas about the diffusion mechanism of the mass transfer process. Grinding the raw material to particles with a size of 2-5 mm contributes to an increase in the speed of technological processes. Since it is known that the course of mass transfer processes is greatly influenced by the specific surface of the processed product, and the finer the grinding of raw materials, the more fully the fat in fat cells is released. When conducting extraction, it is necessary to ensure access of ultrasonic waves to each particle. This is achieved by mixing during sonication. Ultrasonic vibrations at frequencies of 22-44 kHz lead to an increase in the specific interaction surface and a decrease in the diffusion boundary layer, thereby providing multiple acceleration of technological processes.

Figure 1 presents models of cell membranes of adipose tissue before (a) and after (b) exposure to ultrasound: 1 - hydrophilic part of the lipid (dipole), 2 - hydrophobic part of the lipid, 3 - integral (whole) protein, 4 - peripheral protein, 5 - water.

The height of the layer, the processed raw materials and the distance between the emitter and the bottom of the tank are selected in accordance with the ultrasound wavelength at frequencies from 22-44 kHz, calculated by the formula (1), where ν is the speed of sound in water, υ is the frequency.

Traditional high-temperature technologies for extracting fat from fish liver lead to significant changes in the chemical composition of thermolabile components. This primarily relates to polyunsaturated fatty acids and vitamins. The advantage of ultrasonic treatment is that it allows the process to be carried out at an ambient temperature of 10-30 ° C, which allows preserving the thermolabile substances of the raw material, namely polyunsaturated fatty acids and vitamins.

The proposed processing parameters provide the desired product. The use of ultrasonic radiation in the claimed method makes it possible to accelerate the extraction process and, no less important, to increase the yield of the extracted product due to the initiation of mechanical, physico-chemical and biophysical processes in the liver proteins that increase the permeability of cell membranes. Ultrasonic treatment inactivates the lipase enzyme contained in fat-containing raw materials (fish liver), thereby reducing the hydrolytic changes in fat. Fat obtained by ultrasonic extraction is characterized by high quality, high biological value and storage stability. The method is as follows.

As raw materials, fish liver frozen to a temperature of minus 18 ° C is used.

The raw materials thawed to a temperature of minus 1 - minus 5 ° C are crushed in a stainless steel homogenizer to a particle size of 2-5 mm, loaded into an ultrasonic bath, for example Grad 140, with a frequency of 22-44 kHz, generator power from 120-300 W, in stainless steel containers or in plastic containers, while the container with the raw materials in which the processing is carried out is placed at a distance between the emitter and the bottom of the tank at least 1 cm, the processing time of the crushed raw materials in the tank with a layer height of 2.5-12 cm with constant stirring is 5-30 minutes, and The action lead through an aqueous environment having a temperature of 10-30 ° C. After processing, the mass is centrifuged in a precipitation centrifuge with a separation factor of up to 3000 rpm, separating into fat and grax (water-protein residue). After centrifugation, the semi-finished fat is separated to separate impurities, water and protein substances from the fat separators. The yield after separation of 85-98%.

As a result of obtaining fat from the liver of fish in this way, fish oil is obtained that meets the safety and quality indicators in accordance with the requirements of SanPiN, in which:

mass fraction of unsaponifiable substances no more,% - 2.0

peroxide value, mol / kg, not more than - 10.0

acid number, mg KOH in 100 g, not more than 4.0.

The content of toxic elements, mg / kg, not more than:

lead - 1.0

arsenic - 1.0

cadmium - 0.2

mercury - 0.3.

The content of pesticides is not more than mg / kg:

hexachlorocyclohexane (α, β, γ - isomers), not more than, mg / kg - 0.1

DDT and its metabolites no more, mg / kg - 0.2.

The content of polychlorinated biphenyls is not more than mg / kg - 3.0.

The content of radionuclides is not more than Bq / kg:

cesium - 137-60

strontium - 90-80.

The content of vitamin A, mg / g, not less than - 0.06

the content of vitamin D, mcg / g, not less than 1.0

the content of polyunsaturated fatty acids, g /%, not less than 15.

Examples of the method

As raw materials, cod liver frozen to a temperature of minus 18 ° C is used. Studies of the general chemical composition showed that in the cod liver, the fat content is up to 70%, moisture - up to 25% and protein - up to 10%. The cod liver lipid quality indicators were determined: peroxide value - 0.96 mmol of active oxygen / kg, acid value - 2.08 mg KOH / g. The biological value of cod liver lipids: the content of vitamin A is 0.15 mg / g, the content of PUFA ω3 is 18.0%.

Example 1. Thawed to a temperature of minus 1 ° C, the raw materials are crushed in a stainless steel homogenizer to a particle size of 2 mm, loaded into an ultrasonic bath in a stainless steel container, while the raw material container in which the processing is carried out is placed at a distance of 1 cm from emitters. Ultrasonic treatment is carried out on an installation, for example Grad 140, with a frequency of 44 kHz, a generator power of 120 W for 7 minutes, the height of the layer being treated is 2.5 cm. After processing, the mass is centrifuged in a precipitation centrifuge with a separation factor of up to 3000 rpm , separating into fat and graks (water-protein residue). After centrifugation, the semi-finished fat is separated to separate impurities, water and protein substances from the fat separators. The yield after separation of 85%. The peroxide value is 0.96 mmol of active oxygen / kg, the acid value is 2.4 mg KOH / g. The content of vitamin A is 0.13 mg / g. The content of PUFA ω3 is 18.0%.

Example 2. The fat was produced analogously to example 1, except that the ultrasonic treatment was carried out with a frequency of 22 kHz, a generator power of 300 W, and for 20 minutes the height of the processed layer was 8 cm. The finished product after separation was 95%. The peroxide value is 0.96 mmol of active oxygen / kg, the acid value is 2.10 mg KOH / g. The vitamin A content is 0.15 mg / g. The content of PUFA ω3 is 18.0%.

Example 3. The fat was produced analogously to example 1, except that the ultrasonic treatment was carried out with a frequency of 35 kHz, a generator power of 210 W, and for 30 minutes the height of the processed layer was 10 cm. The finished product after separation was 90%. The peroxide value is 0.96 mmol of active oxygen / kg, the acid value is 2.20 mg KOH / g. The content of vitamin A is 0, 13 mg / g. The content of PUFA ω3 is 18.0%.

Claims (1)

A method of obtaining fat from the liver of fish, including thawing raw materials, grinding and processing by physical action, characterized in that the thawing of raw materials is carried out to a temperature of minus 1 - minus 5 ° C, crushed to a particle size of 2-5 mm, and use as a physical effect ultrasound with a frequency of 22-44 kHz, the duration of the processing of crushed raw materials in the tank with a layer height of 2.5-12 cm with constant stirring is 5-30 minutes, and the exposure is through an aqueous medium with a temperature of 10-30 ° C and the distance between STUDIO and bottom capacitance not less than 1 cm, the weight at the end of processing is directed to centrifugation and separation for separating fat from graksy.

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