RU2162648C2 - Method of extracting fat from crab liver - Google Patents

Abstract

FIELD: food industry. SUBSTANCE: fat from crab liver is prepared by autolysis of crushed liver at temperature of 20-70 C for 40-240 min at mixing. EFFECT: extended raw base for production of fat possessing biologically active properties; increased quality and yield of fat. 4 ex

Description

 The invention relates to the fishing industry and can be used to obtain fat from crab liver, which has a high biological effect.

A known method of separating fat from fish liver used in Norway (MEStansby "Fish Oils" Westport, Connecticut, The AVI Publishing Company, Inc., 1967, pp. 194-5, 201-2). The method consists in the fact that the fish liver is placed in a heated apparatus and sparged from the bottom with hot steam for 1 hour at 90 ^o C. After this heating, the yield of crude fat is 70% of that contained in the liver. Further heating and pressing of the residue results in a dark fat with a high content of free fatty acids. Installation is simple and inexpensive, but does not provide the required yield and product quality.

Known Swedish (Laval) process for the allocation of fat from fish liver ((MEStansby "Fish Oils" Westport, Connecticut, The AVI Publishing Company, Inc., 1967, pp. 194-5, 201-2). The method includes the following operations: fish the liver is fed into an intermediate heating tank, then pressed through a grate to grind and remove the liver veins and served in a heater with a temperature of t = + 85 ^o C, where it is kept for some time; then the liver enters a separator in which the fat is separated from the water-protein mass The yield of crude fat is more than 90% based on the total fat content in the liver.

A known method of melting fat from the liver of fish (A.S. USSR N 1482935, IPC4 C 11 B 1/12), which includes sorting, washing, grinding the liver and melting at a temperature of 50-70 ^o C. The fat yield is from 85% to 94% of its original content. The disadvantage of this method is the low yield of 85%.

 A known method of producing fish oil (AS USSR N 1414863, IPC4 C 11 B 1/14) from the liver and viscera of fish, including grinding raw materials and heat treatment with a solution of urea (2-2.5% urea to the mass of raw materials. Disadvantages : low yield of 50-79% and the use of an additional chemical reagent.

A known method of extracting fat from the liver of fish and whales using alkaline hydrolysis of minced liver (G.V. Krutchensky "Vitamin A production technology" Far Eastern Book Publishing House, Vladivostok, 1968, p.40-45). Such hydrolysis destroys protein-lipid complexes in the liver cells, resulting in an increase in the yield of separated fat. However, this method has a number of significant drawbacks, as the author himself mentions: firstly, the use of alkali up to 4.5% by weight of the liver negatively affects the structure of the fat itself - it degrades with the formation of significant amounts of free fatty acids, and secondly, alkali in this concentration and in combination with the temperature regime (90-95 ^o ) provides the formation of stable emulsions, leading to the loss of the recovered product. Other disadvantages include the non-environmental friendliness of this production method, because the use of alkali in the future will require the same amount of sulfuric acid to neutralize, waste will be significant.

 It is generally known that the crab liver contains fat in an amount of up to 24% and can potentially be a source for the extraction of fat, as indicated in the book of B.V. Zikeev, "Processing of non-fish raw water", M .: Pishchepromizdat, 1950, S. 277, but no data on the method of production of fat or technological parameters that characterize any method is not given.

 The problem solved by the invention is the expansion of the raw material base for obtaining fat with biologically active properties, improving the quality and yield of fat, as well as improving the environmental friendliness of the process.

The problem is solved in that the crab liver is used as a raw material, and fat is released by autolysis of the crushed liver with stirring at a temperature of 20-70 ^o C for 40-240 minutes

 Harvested liver (in its pure form without shell) of king crab Paralithodes camtschatica, blue Paralithodes platypus, opilio shear Chionoecetes opilio and prickly Paralithodes brevipes is a brown mass of long stretching strings, which smells quite good and has an unpleasant smell in relation to the skin in view of the presence of large quantities of enzymes. The liver hardens well at sub-zero temperatures and is usually stored in plastic bags in the refrigerator. Hepatopancreas or crab liver accounts for more than 90% of the intestines of carapace and 10% of the total weight of the crab. The fat content in the liver varies from season to 10-15% by weight. The volume of crabs is more than 10 thousand tons.

 The crab liver tissues initially contain significant amounts of the proteolytic collagenase enzyme. Collagenase is an enzyme that destroys the protein structures of cells, in particular lipid-protein formations. If you create certain conditions: temperature, temporary, mechanical, then you can achieve enzymatic catalysis in optimal conditions. Thus, collagenase, destroying the structure of cells, thereby releases the fat contained in them and allows a gentle, gentle way to overcome the most important stage of fat extraction.

The essence of the method is as follows: the frozen liver of the crab is crushed on top, loaded into a reactor, in which autolysis is carried out with stirring at a temperature of 20-70 ^o C for 40-240 min, then the mass is fed to a mud separator to separate fat from water-protein fractions and for final cleaning on a fat separator. Next, the fat is pumped into the converter, where free fatty acids are neutralized with an alkali solution (its amount is determined on the basis of laboratory tests), they are held for up to 12 hours, an average of 6 hours, after which the heavy fraction is drained from the lower valve - soapstock (sodium soaps of fatty acids) , which is waste and goes to a neutralization column for further disposal. Next, the fat is washed 3 times with water and fed to a vacuum dryer, to which bleaching clay or active earth is added up to 2% by weight of fat and kept under stirring under vacuum for 2 hours. Then the mixture is filtered through a cloth (belting) on a suction filter and the finished product is poured into an airtight container.

It was experimentally established that lowering the temperature below 20 ^o C leads to a decrease in the yield of fat from raw materials; so, this figure is reduced to 60-75%. Raising the temperature above 70 ^o C leads to a decrease in the yield of the target product to 70%. Crab collagenase is a very stable enzyme: it does not lose part of its activity even at 80 ^o C, but the process at this temperature is ineffective.

Usually, at optimal temperatures and stirring, keeping the liver in the reactor or screw for more than 4 hours does not make sense, since the cells are already destroyed and the fat is in a free state. Reducing the shutter speed less than 40 minutes reduces the yield of fat. In all cases, mixing is also a necessary part of the process. In its absence, local stagnant zones can form, as a result of which the autolysis process will not be effective. The experiments showed that at low temperatures (20 ^o C and above), intensive mixing of the mass with a stirrer (up to 100 rpm) is necessary, since this ensures its homogeneity, which is an important factor in autolysis. At higher temperature values of the process (up to 70 ^° C.), a natural turbulent mixing occurs in the mass of the homogenized liver and the use of a mixer does not increase the efficiency of the process.

 The Institute of Nutrition RAMS (Moscow) investigated crab fat samples for its harmlessness and the possibility of use in food. The report provided to us not only shows the harmlessness of crab fat, but also notes its useful biological properties that make it possible to talk about this product as a therapeutic and prophylactic one. So, for example, in the Conclusion it was concluded: “fat from crab liver is an effective source of omega-3 acids in the diet, has some immunostimulating effect, does not adversely affect hematological parameters, contains a complex of active bioantioxidants that reduce the level of lipid peroxidation, and is recommended in as a dietary supplement. "

 Sea fats, in particular fish ones, have always been popularized in terms of their content of polyene OMEGA-3 fatty acids, primarily eicosapentaenoic. So, in people who have consumed significant amounts of these acids inside, there are rare cases of diseases such as myocardial infarction, atherosclerosis, asthma, diabetes mellitus, multiple sclerosis, psoriasis, thyroid toxicosis (BAMueller, RLTalbert "Biological mechanisms and cardiovascular effects of omega- 3 fatty acids ", Clinical Pharmacy, 1988, N 3, p. 139-145). OMEGA-3 series polyene fatty acids are most widely used among world pharmaceuticals as a means of preventing and treating cardiovascular diseases (BAMueller, RLTalbert "Biological mechanisms and cardiovascular effects of omega-3 fatty acids", Clinical Pharmacy, 1988, No. 3, p. 139-145; RGAckman "Perspectives on Eicosapentaenoic Acid", n-3 News, v.1, N 4. p. 1-4; RGAckman "The year of fish oils", Chemistry and Industry, 1988, N 3, p. 139-145). If earlier, medical fish oil was only a source of vitamins A and D, then in the 1997 edition M.D. Mashkovsky (M.D. Mashkovsky "Medicines", edition 13, Kharkov, "Torsing", 1997, t .II, pp. 67-69, 72) notes the effect of polyenoic acids and their metabolites on human health. Therefore, I want to emphasize the fact that the report of the Institute of Nutrition RAMS shows the effective role of OMEGA-3 acids from crab fat. That is, fat from crab liver is a worthy substitute for fish oil, while having certain advantages - it does not contain vitamin A, but contains beta-carotene, thereby reducing the risk of toxicosis with a higher dose of its consumption. Vitamin A in excess causes hypervitaminosis, which is a limitation of the amount of consumed medical or other fat from the liver of fish. In the case of the use of fish oil for the prevention of the cardiovascular system, when its consumption should be more significant, this fact is a significant obstacle. Crab fat from this point of view is really a unique food product.

 On the basis of the whole range of work that we carried out in 1998, in the TINRO Center a draft documentation was prepared (Technical Specifications and Technological Instructions) for "Food from therapeutic and prophylactic crab liver fat" for subsequent approval, and a working tasting council was approved that approved crab fat as high-grade food product (Tasting certificate attached).

 The essence of the method is illustrated by examples.

 EXAMPLE 1

 To receive fat, the liver of king crab Paralithodes camtschatica was taken in the amount of 100 kg of 4-month storage.

 The fat content in the liver is 11% by weight. The total fat content in the liver is 11 kg.

The liver in the frozen state is fed to the top, where it is crushed and then fed through a conveyor to the reactor with a stirrer. Hot water is fed into the reactor jacket and, with stirring (60 revolutions of the stirrer per minute), the liver is heated to 40 ^° C, controlling the temperature with a thermometer. The process continues for 2 hours. Then, a homogeneous solution is fed to a mud separator, where fat is separated from the aqueous protein residue. Further, to clean the fat, it is again passed through a fat separator, from where the fat enters the next stage. The yield of crude fat is 10.6 kg or 96.3%.

 The neutralization of free fatty acids in crude fat is carried out in an apparatus with a jacket and a stirrer. In the laboratory, the acid number (CN) is determined. In this case, it is equal to 10 mg KOH / g fat.

Required amount of NaOH with 5% excess:
10,600 g · 10 (CN) · 0.714 · 1.05 (5%) = 79468 mg = 0.0795 kg
Excess alkali during refining of fats can reach 50%, but usually no more than 10-12%. This is due to the fact that part of the alkali does not bind to fatty acids, but to a protein residue and other substances. The required alkali excess is determined on the basis of preliminary experimental data.

The alkali is dissolved in 2 l of water and heated to 95 ^o C. At this time, the fat pumped into the apparatus is heated with stirring. When the temperature reaches 90-95 ^o C, stirring is stopped and an alkali solution is introduced into the fat through nebulizers. At the end, a 12% sodium chloride solution, also heated to 90-95 ^o C in an amount of 1 liter, is added to the neutralizer through the nebulizers. Then the fat is defended for 6 hours. After that, a thick soap stock is drained from the bottom valve, which goes for further processing into a neutralization column.

A 3-fold washing of fat from alkali residues is carried out in the same apparatus at a temperature of 90 ^o C, adding each time with stirring 2 l of water heated to 90-100 ^o C. Then the fat is allowed to settle for 30 minutes and the water is drained into the sewer. Next, the fat is fed into a vacuum dryer.

In a sealed vacuum drying apparatus, the fat is heated with stirring to 90 ^o C and serves a vacuum with a vacuum of at least 700 mm Hg, incubated for 1 hour. Then, without dropping the vacuum, bleaching clay in the amount of 0.2 kg (2% of the weight of fat) is fed into the apparatus and stirring is continued for another 1 hour. Then the fat goes to the filtration.

 Filtration is carried out on a suction filter, using belting as a filter material. Then the finished product is weighed and its quality indicators are determined.

Received refined crab fat, kg - 8.2
The output based on the fat content in the liver,% - 74.5
Refined Crab Fat Characteristics:
Cf, mg KOH / g fat: 1.0;
The total content of the main OMEGA-3 acids - eicosapentaenoic and docosahexaena (of the total amount of fatty acids): 14.4%;
Brown colour;
transparency: transparent;
smell: sea grass;
Flavor: Fish oil without rancidity.

 EXAMPLE 2

 To obtain fat, the liver of the blue crab Paralithodes platypus was taken in an amount of 100 kg and a shelf life of 6 months.

 The fat content in the liver is 9.5%, the total fat content is 9.5 kg.

 All operations are carried out as in Example 1, with some changes.

Autolysis is carried out at 20 ^o C for 4 hours (stirrer - 100 rpm).

 The yield of crude fat after the second separator was 8.74 kg or 92%.

 To. H = 12. The amount of sodium alkali with a 5% excess is 0.0786 kg.

 Bleaching clay is taken in an amount of 0.070 kg, which is about 1% by weight of fat.

Received refined crab fat, kg: 7.08
The output based on the fat content in the liver,%: 74.5
Refined Crab Fat Characteristics:
Cf, mg KOH / g fat: 1.3;
The total content of the main OMEGA-3 acids - eicosapentaenoic and docosahexaine (of the total amount of fatty acids),%: 15.7;
Brown colour;
transparency: transparent;
smell: sea grass;
taste: fish without rancidity.

 EXAMPLE 3

 To obtain fat, the liver of commercial crab-stringer opilio Chionoecetes opilio in the amount of 100 kg and a shelf life of 4 months was taken.

 The fat content in the liver was 8.9% or 8.9 kg for the entire weight of the liver.

 The technological process was carried out, as in Example 1, with some exceptions.

Autolysis is carried out at a temperature of 50 ^o C for 1.5 hours (mixer - 40 rpm).

 Received crude fat 8.26 kg, yield 93%.

 CN = 9. Sodium alkali with a 10% excess take 0.0584 kg.

 Bleaching clay is loaded in an amount of 0.036 kg (0.5% by weight of fat).

Received refined crab fat, kg: 6.7
The output based on the fat content in the liver,%: 75.3
Refined Crab Fat Characteristics:
Cf, mg KOH / g fat: 1.5;
The total content of the main OMEGA-3 fatty acids - eicosapentaenoic and docosahexaenoic (total of total fatty acids),%: 15.2;
Brown colour
transparency: transparent
smell: sea grass;
Flavor: Fish oil without rancidity.

 EXAMPLE 4

 To obtain fat, the liver of prickly crab Paralithodes brevipes was taken in an amount of 100 kg and a shelf life of 7 months.

 The fat content in the liver is 9.2% or 9.2 kg in the entire liver.

 The technological process is carried out, as in Example 1, with some exceptions.

Autolysis of the liver is carried out at a temperature of 70 ^o C for 40 minutes (without stirring).

 The yield of crude fat is 8.4 kg or 91.3% of the total fat.

 CN = 14. The amount of sodium alkali with a 5% excess is 0.088 kg.

 0.1 kg of bleaching clay was taken, which is approximately 1.5% by weight of fat.

Received refined crab fat, kg: 6.0
The output calculated on the fat content in the liver,%: 65.2
Refined Crab Fat Characteristics:
Cf, mg KOH / g fat: 1.1;
The total content of the main OMEGA-3 fatty acids - eicosapentaenoic and docosahexaenoic (of the total amount of fatty acids),%: 12.2;
Brown colour;
transparency: transparent;
smell: sea grass;
Flavor: Fish oil without rancidity.

 In Russia, there is an acute shortage of their own inexpensive medicines, which is why this invention is an important link in the national program to saturate the market with healthy products, and also allows solving problems of increasing the efficiency of use of the extracted marine resources with significant savings in reagents, electricity and labor.

Claims (1)

A method of obtaining fat from crab liver, including grinding the liver, the release of fat by autolysis at a temperature of 20 - 70 ^o C with stirring for 40 - 240 minutes, the separation of fat and its purification to obtain the target product.