RU2207033C2 - Method for wasteless complex reprocessing of chitin-containing raw material - Google Patents

Abstract

FIELD: food-processing industry. SUBSTANCE: method involves providing enzymic hydrolysis of proteins of chitin- containing raw material with the use of protein-degrading enzyme released from raw crab hepatopancreas or enzyme preparation released therefrom; purifying resultant hydrolyzate solution through combined deposition of lipids and insoluble substances by chitosan; drying purified protein hydrolyzate; producing chitin by providing first deproteinization process at temperature below 20 C; providing deacetylation of chitin with the use of 20-60% sodium hydroxide solution with sodium hydroxide solution and wetted chitin ratio of (20-60):1 at temperature of 95-120 C while periodically mixing, with initial stage of deacetylation process being carried out for 5 min in vacuum under pressure of 0.5-1.0 kg/sq. cm. Method may be used for producing chitin/chitosan and enzymic protein hydrolyzates used as base for microbiological nutrient media. EFFECT: increased efficiency in utilizing crustaceous reprocessing wastes and reduced contamination of sewage water with protein product upon obtaining of chitin. 5 tbl, 4 ex

Description

 The invention relates to methods for complex processing of waste from fishing for crustaceans, including substandard shrimp caught in by-catch of non-commercial species of crustaceans, waste from the processing of crabs, shrimps and other crustaceans, with the aim of producing chitin, chitosan and enzymatic protein hydrolysates intended for use as the basis for microbiological nutrient media.

There is a method of producing enzymatic protein hydrolysates for microbiological media from non-food organs and pinnipeds obtained by the action of this raw material on enzyme-containing organs of animals of the same species, for example, pancreas of seals (Pat. 1402616 Russia, MKI ⁴ C 12 N 1/20. Method for producing the basis of nutrient media for the cultivation of microorganisms / E. S. Girshovich, N. V. Kozlova, G. A. Gerasimova and others - 4196453/28; Declaration 19.12.86; Publ. 15.06.88, Bull. 22). According to this invention, non-food organs and muscle tissue of pinnipeds, mainly seals, having uterine and secondary hair, are used as protein-containing raw materials. This raw material is crushed together with bones, filled with water (1: 2), heated and adjusted to pH 8.0. Bones are a source of inorganic ions necessary for the growth of microorganisms, as well as collagen hydrolysis products. The use of raw materials together with bones, in addition to improving quality, eliminates the time-consuming stage of separation of meat from bones and increases the yield of the target product due to the non-waste use of meat. An enzyme source is then added using the enzyme-containing organs of animals of the same species, for example, pancreatic mincemeat. Used in the method, such enzyme-containing organs of pinnipeds, such as the intestines, stomach, pancreas, are non-utilized wastes of hunting. Hydrolysis is carried out at 50 ^o C for 24 hours. The resulting hydrolyzate is filtered off, acidified with acetic acid to pH 5.4, boiled, filtered and dried on a spray dryer.

One of the technical solutions close to the invention is a method for producing enzymatic protein hydrolysates from various protein raw materials under the action of a proteolytic complex from crab hepatopancreas (Pat. 2039460 Russia, MKI ⁶ A 23 J 3/00. Method for producing protein hydrolyzate / Artyukov A. A., Kozlovskaya E.P., Kozlovsky A.S. et al. - 93031307/13; Declared June 9, 93; Published July 20, 95, Bull. 20). Enzymatic hydrolysis of raw materials of various origins (vegetable, milk proteins, animal proteins, soy isolate, pea, wheat or corn flour, casein and whey proteins, minced meat, minced fish, minced seafood, collagen, gelatin, albumin and blood hemoglobins) is carried out with neutral or slightly alkaline conditions (pH 8) in the presence of a proteolytic complex from the hepatopancreas of commercial crabs. Hydrolysis is carried out for 5-8 hours at a temperature of 37 ^o C, then the enzyme preparation is inactivated at 95-100 ^o C, followed by cooling.

Closest to the invention, the technical solution is a method of waste-free complex processing of chitin-containing raw materials (Pat. 2123269 Russia, MKI6 A 23 L 1/33, A 23 J 1/04, 08 V 37/08. Method of waste-free complex processing of chitin-containing raw materials / Levonkov S .V., Kupina N.M., Blinov Yu.G. - Declaration. 24.09.97 - 97 115965/13; Publ. 20.12.98, Bull. 35). The method includes pressing raw materials with the separation of the protein fraction, a complex of chitin and proteolytic enzymes and fat to produce a protein product and pulp, washing the pulp with water at a ratio of pulp and water 1: 2 and a temperature not exceeding 25 ^o C, its deproteination, demineralization by treatment with hydrochloric acid, followed by separation into chitin and an acid hydrolyzate, washing chitin to a neutral reaction with water, purifying chitin from proteins by treatment with an alkali solution, followed by separation of the alkaline hydrolyzate and washing chitin ode to a neutral reaction, followed by drying and obtaining the finished product, mixing, combining acid hydrolysates obtained in the demineralization step and alkaline hydrolysates obtained in the post-purification stages of chitin, until a neutral pH is achieved, followed by separation of the mineral-protein precipitate, characterized in in that the non-heat treated raw materials used PCP crab production, the liquid fraction after compressing raw material is subjected to autolysis for 2-6 hours at a temperature not higher than 12 ^o C, Center they are quenched to obtain protein paste, fat and a solution of proteolytic enzymes, post-treatment of fat and a solution of proteolytic enzymes is carried out by separation and filtration through a suction filter to obtain a complex of proteolytic enzymes and a semi-finished fat, de-proteination of pulp after washing with water is carried out for 1-24 hours with the resulting solution complex proteolytic enzymes having a pH of 7.5-8.0 and containing 1-10% by weight of an enzyme preparation having proteolytic activity feedstock preparation 60-200 CFU / g, at a temperature of 4-60 ^o C, and with in relation to raw materials: a solution of 1: 1-1: 1.5 with separation of the protein hydrolyzate, the remaining pulp is treated with vegetable oil to obtain an oil extract of carotenoid pigments, and the resulting pulp is demineralized with 1-5% hydrochloric acid at room temperature at a ratio of 1: 12-1 : 16 for 0.5-20 hours, followed by washing it with water, carry out post-treatment of proteins to obtain the final product of chitin. The purification of chitin from proteins is carried out with 2.5-4% alkali at a temperature of 55-65 ^o C for 2.0-2.5 hours at a ratio of chitin: solution equal to 1: 10-1: 5.

 There is also a known method for the isolation of chitin, including the enzymatic deproteinization of crustacean shells (Rogozhin S.V., Lozinsky V.I., Fokina S.S., Oreshenko L.I., Gamzazade A.I., Tsyryapkin V.A .; INEOS AN USSR Method of isolating chitin of aquatic organisms: A. S. 1022463 USSR, MKI C 08 V 37/08. Method for isolating chitin of aquatic organisms / Lozinsky V. I., Fokina S. S., Oreshenko L. I., Gamzazade A. I. , Tsyryapkin V.A. 3351422/23/05; Decl. 19.10.81).

A method of isolating chitin of aquatic organisms, including enzymatic deproteinization (DP) and acid decalcification (DK) of the shell, characterized in that in order to simplify and reduce the cost of the process, as well as reduce the amount of environmental polluting waste, the DP and DK are simultaneously treated with an aqueous solution of acidic proteolytic acid enzymes of microbiological origin at a pH of 1.5-4.5 and 15-60 ^o With 1-48 hours at a ratio of enzyme: substrate shell 1: 1-1: 1000. As acidic proteolytic enzymes of microbiological origin, acidic proteases are used - proteolytic enzyme complexes selected from the group: Aspergillus niger, Aspergillus foetidus, Aspergillus awamore, Aspergillus oryzae.

 A known method of producing chitosan, in which the reuse of alkali for deactivation of chitin is patented (Patent 2087483 Russia, MKI6 08 08 37/08, 01 J 20 / 3O. Method for producing chitosan / Owl VV, Freiman D. B., Bannikov V.V., Lvovich F.I.- 93055356 / 25.-Declaration 21.12.93; Publ. 20.08.97, Bull. 23).

A method of producing chitosan, including grinding natural chitin-containing raw materials, decalcification with a 1-5% solution of hydrochloric acid, deproteinization with a 1-5% solution of sodium hydroxide, washing and deacetylation with a 46-47% solution of sodium hydroxide at 80-85 ^o C chitosan and separation from the mother liquor, characterized in that the chitin-containing raw material is ground, and then prior to washing is performed three cycles of alternating stages of deproteinization and decalcification, wherein deproteinization is carried out at 60-85 ^o C for 1-3 hours, decalcifying vanie at 35-55 ^o C for 0.5-2 hours, with each successive cycle of the alternating stages is carried out at a higher temperature than the previous one. The mother liquor from the deacetylation step is concentrated and fed to the deacetylation step.

 The present invention expands the raw material base for the production of chitin, chitosan and enzymatic protein hydrolysates for microbiological environments through the use of substandard products and industrial waste and processing of crustaceans, as well as the use of crude hepatopancreas of king crab or enzyme preparation obtained from it, as a highly active enzyme preparation of a wide spectrum of proteolytic and collagenolytic activity.

 Before obtaining chitin / chitosan from chitin-containing raw materials, the proposed method involves the preliminary enzymatic hydrolysis of shrimp and crab fishing waste proteins by the action of hepatopancreas-raw king crab or proteolytic enzyme preparation isolated from it, with the ratio of enzyme preparation / hepatopancreas-raw raw-food: protein-containing raw materials crustaceans, as 1-10 / 10-200 g: 1 kg.

 The resulting hydrolyzate is purified by centrifugation and degreased using a coagulant - chitosan, the precipitate is again separated by centrifugation. The resulting clear hydrolyzate solution was evaporated in vacuo and dried.

Chitin-containing precipitate (shell) is washed with water, dried or used moist to obtain chitin and chitosan. Chitin is obtained by sequential treatment of the shell with solutions of alkali (deproteinization), acid (demineralization). The first deproteinization is carried out at a temperature below 20 ^o C. Chitosan is obtained by treating chitin with a 20-60% sodium hydroxide solution at an elevated temperature in the range of 95-120 ^o C and a ratio of sodium hydroxide solution: wet chitin / chitosan (20-60): 1 with periodic stirring. In this case, the start of the deacetylation process for 5 minutes is carried out at a vacuum pressure of 0.5-1.0 kg / cm ² . Processing can be repeated 2-3 times to obtain a high degree of deacetylation.

 The raw materials for the hydrolyzate are shrimp fishing waste (substandard shrimp, scrap), Kamchatka crab processing waste and other crustacean and chitin-containing waste from their processing. Obtaining a hydrolyzate is part of a comprehensive waste-free processing of commercial waste and crustacean processing. The use of substandard shrimp for producing chitin is disadvantageous, since the yield of the finished product is about 1.5%, which is 3-4 times less than the yield of chitin from the carapace obtained after mechanical processing of the shrimp by aero- or hydroheating. The use of commercial waste for feed purposes is also inefficient, since obtaining chitin is more economically feasible.

 In this regard, we propose to preliminarily carry out enzymatic hydrolysis of all the proteins of the separated carapace to obtain a protein hydrolyzate with a higher consumer value. After receiving and separating the liquid hydrolyzate, a dense residue is formed - a chitin-containing carapace, which is the raw material for producing chitin. The present invention expands the raw material base for the production of chitin, chitosan and enzymatic protein hydrolysates for microbiological environments through the use of substandard products and industrial waste and processing of crustaceans, as well as the use of crude hepatopancreas of king crab or enzyme preparation obtained from it, as a highly active enzyme preparation of a wide spectrum of proteolytic and collagenolytic activity.

 The use of a proteolytic complex obtained from hepatopancreas of commercial king crab allows us to obtain products other than products obtained using other enzyme preparations. This is due to the fact that the proteases contained in the crab complex have a unique substrate specificity that distinguishes them from other proteolytic enzymes used.

Thus, the use of the invention allows to solve the following tasks:
- Dispose of non-food, previously non-utilized protein-containing raw materials - waste of crustaceans: shrimp and crab proteins, crab hepatopancreas;
- to obtain an enzymatic protein hydrolyzate for microbiological culture media;
- to simplify the process of producing chitin and reduce the degree of pollution of wastewater with protein products due to the preliminary enzymatic hydrolysis of raw materials to obtain protein hydrolyzate (preliminary cleaning of the shell of crustaceans from a significant portion of the proteins);
- obtaining high-quality chitin and chitosan.

 The method according to this invention is as follows.

Raw materials are thawed, crushed on a homogenizer, spinning top or other device until a homogeneous mass with a particle size of the shell from 1 to 10 mm. The crushed raw material is loaded into the apparatus with a mixing device and a heating jacket, water is added at a ratio of the mass of raw materials and water equal to 1: 1. The enzyme preparation is loaded in an amount of 1 to 10 g per 1 kg of raw material or raw hepatopancreas, depending on the activity - from 10 to 200 g per 1 kg of raw materials. The resulting mixture is stirred, heated to (50 ± 5) ^o C. Hydrolysis is carried out at the indicated temperature for 3-10 hours with stirring. After hydrolysis is complete, the mixture is heated to 95-100 ^o C for 10-60 minutes, then cooled to room temperature and the precipitate is separated by centrifugation.

 The resulting hydrolyzate solution with a pH of about 8.5 is acidified with stirring to a pH of not more than 6.5 with a solution of hydrochloric acid with a concentration of hydrogen chloride from 5 to 25%.

 Chitin-containing precipitate is washed with water 2-3 times, dried or immediately used to obtain chitin. Dry sediment contains residual proteins 25-40%, ash 35-50%, chitin up to 40%, lipids less than 0.5%. This composition favorably distinguishes chitin-containing wastes after enzymatic hydrolysis from chitin-containing wastes generated after shrimp mechanical peeling, primarily, a higher mass fraction of chitin. In addition, after enzymatic hydrolysis in the shell, the fat content is significantly reduced (table. 1).

 A coagulant is added to the hydrolyzate solution - a solution of chitosan in 0.05-0.2 N. solution, kept with stirring for 10 to 60 minutes, then the mixture was neutralized to a pH of 7.5 to 9.0 and kept with stirring until a precipitate formed for 10-60 minutes. The resulting suspension is centrifuged or filtered. After separation of the precipitate, the pH of the hydrolyzate solution is adjusted by adding hydrochloric acid to a value of 7.2 ± 0.3.

 The clear hydrolyzate solution is evaporated under vacuum to a mass fraction of solids from 30 to 65%. One stripped off solution is dried in a dryer of any design to a residual mass fraction of water of not more than 4%. When using a spray dryer or an inert carrier dryer in a fluidized bed, the hydrolyzate solution can be dried without prior evaporation.

 The resulting dry hydrolyzate is soluble in water to a concentration of 3-5%. Mass fraction of fat from 0.3 to 0.8%. Yield 10 to 15%.

To obtain chitin / chitosan, the wet shell is loaded into the reactor and a solution of sodium hydroxide with a concentration of from 1 to 4% is poured. The first deproteinization is carried out at a temperature below 20 ^o C for 0.5-2 hours with constant or periodic stirring. After the first deproteinization, the suspension is sent to the separation of the precipitate by centrifugation (preferably by precipitation) or by filtration. The liquid part is directed to the precipitation of proteins, the deproteinized shell is washed with water to a neutral pH of the wash water and sent for demineralization.

Demineralization is carried out with a 3.6% solution of hydrochloric acid at a temperature of 15-25 ^o C for 0.5-2 hours with constant or periodic stirring. After demineralization, the suspension is sent to the separation of the precipitate by centrifugation or filtration. The liquid part is directed to the deposition of mineral salts, the demineralized shell is washed with water to a neutral pH of the wash water and sent to the second deproteinization.

The second deproteinization is carried out with a 4% sodium hydroxide solution at a temperature of 90-98 ^o C for 0.5-2 hours with constant or periodic stirring. After the second deproteinization, the suspension is sent to the separation of the precipitate by centrifugation or filtration. The liquid part is sent for neutralization and discharge, the chitin is washed with water to a neutral pH of the wash water and sent for drying or obtaining chitosan.

 After the first deproteinization, the dissolved protein substances are precipitated from the alkaline solution by neutralization with hydrochloric acid to a solution pH of not more than 5.5. The precipitate is separated by centrifugation or filtration, dried and used as an additive in animal feed. The solution is drained.

 From the acid solution after demineralization, mineral calcium salts are precipitated by neutralization with a saturated solution of calcium carbonate to a pH of at least 9. The precipitate is separated by centrifugation or filtration, dried and used for feed or technical purposes. The solution is drained.

 Qualitative indicators of chitin are shown in table 2 of the examples of the method.

 Chitin is used to produce chitosan or glucosamine hydrochloride.

 Chitosan is obtained from dried and wet chitin.

Deacetylation of dried chitin is carried out with a 20-60% solution of sodium hydroxide at a temperature of 95-120 ^o C for 30-90 minutes with constant or periodic stirring. In order to improve the hydrodynamic conditions of the deacetylation reaction and the conditions for the regeneration of caustic soda solution, the mass ratio of the caustic soda solution and chitin (chitosan during repeated treatments) was increased from 20: 1 to 60: 1. After the end of the process, the solution is separated by filtration or centrifugation, and after adding the necessary amount of alkali and water, they are reused for deacetylation of chitin or chitosan. Chitosan is washed with water at a temperature of 85-98 ^o C to a neutral pH of the wash water, dried or used wet for deeper deacetylation. The second and third deacetylation is carried out similarly to the first. Get chitosan with a degree of deacetylation from 65 to 99%, depending on the frequency of treatment with a solution of sodium hydroxide and the duration of each of the treatments.

In order to exclude drying operations of intermediate products (chitin and chitosan), de-acetylation of wet chitin / chitosan is carried out. In this case, an alkali solution with a concentration of 20-60% is preliminarily prepared by heating to 80-90 ^° C, taking into account the mass fraction of water in wet chitin / chitosan. Table 2 shows the parameters of alkali solutions necessary for deacetylation of 100 kg of wet chitin with a mass fraction of water of 75%.

As can be seen from Table 2, at ratios of 10: 1 and 15: 1, which are usually used for deacetylation, using moist chitin will require the preparation of a NaOH solution with a concentration of more than 60%, which can cause difficulties even during short-term storage of such a solution due to rapid crystallization of alkali. At a concentration above 70%, a temperature above 100 ^° C will be required. Adding moist chitin to an alkali solution with this temperature will cause the reaction mixture to boil due to the added water.

 Thus, we came to the conclusion that when deactivating wet chitin, the ratio of alkali to chitin solution should be increased by more than 20: 1. This has a number of positive aspects. At large ratios, a more uniform mixing of the reaction mixture occurs, which leads to a more uniform product. During the regeneration of the alkali solution, the dissolution of the additional amount of NaOH is simpler, since the change in the concentration of the solution is from 2.5 to 5.5%, and the solution does not require intensive heating for short storage.

 In order to intensify the processes of deproteinization and demineralization of the carapace, deacetylation of chitin / chitosan, it is proposed to carry out short-term evacuation of the reaction mixture after loading all reagents and raw materials. During evacuation, water boils in the pores of moist products (shell, intermediate products, wet chitin / chitosan), as a result of which, after restoration of atmospheric pressure, the pores are easily filled with a reagent solution. The most effective short-term evacuation during deacetylation of wet chitin / chitosan. Uniform rapid absorption of a 20-60% NaOH solution provides a more homogeneous product, which affects, first of all, the mass fraction of acid insoluble substances (see table 5 for example 4).

The proposed method of integrated processing of industrial waste and processing of crustaceans has the following advantages:
- the implementation of the integrated use of raw materials, which does not require preliminary separation of its components, in particular the separation of the shell, and uses almost all the waste;
- the use of hepatopancreas raw crab or, if necessary, an enzyme preparation obtained from it, allows for highly efficient enzymatic hydrolysis of proteins. At the same time, high mass fractions of the target product, namely free amino acids and lower peptides in protein hydrolysates, were obtained. The high content of free amino acids in the hydrolyzate, which largely characterizes the depth of enzymatic hydrolysis, is achieved due to the fact that the complex preparation of proteinases from hepatopancreas of king crab was used, which has a high affinity for the tissues of crustaceans included in the diet of the crab;
- simplification of the process of cleaning the hydrolyzate solution from ballast insoluble proteins and lipids through the use of an effective coagulant of organic substances - chitosan;
- preliminary enzymatic treatment allows you to get a shell of crustaceans (raw materials for further processing and obtaining chitosan) with a lower content of proteins and lipids compared with the shell after mechanical peeling;
- the precipitation of protein and minerals is carried out with high yields separately from alkaline and acid solutions after receiving chitin;
- there is an optimization of the process of chitin / chitosan deacetylation due to an increase in the mass ratio of a 20-60% solution of caustic soda and wet chitin / chitosan, which improves the hydrodynamic conditions of the deacetylation reaction and the regeneration conditions of the sodium hydroxide solution during deacetylation;
- obtaining a product of a uniform quality due to short-term evacuation of the reaction mixture at the beginning of deacetylation, which ensures the fastest possible wetting of wet chitin / chitosan with an alkali solution.

 Example 1

 Obtaining chitin and an enzymatic protein hydrolyzate from shrimp fishing waste using an enzyme preparation from hepatopancreas.

2.5 kg of boiled-frozen shrimp fishing waste was thawed in air at room temperature, crushed on a homogenizer to a homogeneous mass with a shell particle size of not more than 3 mm. The crushed raw materials were charged into a 10 L flask with a mixing device. Poured 2.5 kg of water. 18 g of dry enzyme preparation obtained from hepatopancreas of king crab were loaded. The mixture was stirred, heated in a water bath to (50 ± 5) ^° C. Hydrolysis was carried out at a temperature of (50 ± 5) ^° C for 6 hours. After hydrolysis was completed, the temperature in the water bath was brought to 97-98 ^° C and the reaction mixture was warmed up in the flask for 45 minutes Then the mixture was cooled to room temperature. The precipitate was separated by centrifugation at 8000 rpm for 30 minutes.

 Received 3.69 kg of a hydrolyzate solution with a pH of 8.5. The resulting solution was neutralized with 18% hydrochloric acid to a pH of 6.5. 350 g of a 1% solution of chitosan in 0.1 N were added to the solution with stirring. hydrochloric acid solution, the mixture was kept under periodic stirring for 20 minutes, then neutralized to pH 8.25 by adding a 20% solution of sodium hydroxide and kept under periodic stirring for 30 minutes. The suspension was centrifuged at 8000 rpm for 30 minutes.

The obtained clear hydrolyzate solution was evaporated under vacuum on an IR-10M rotary evaporator to a mass fraction of solids of 47%. One stripped off solution was dried in a vacuum oven at a temperature not exceeding 80 ^o C. Dry hydrolyzate was crushed.

 Received 251 g of dry hydrolyzate, completely soluble in water to a concentration of 5%. Yield 10%. The chemical composition and amino acid composition of the hydrolyzate are shown in tables 3 and 4.

 Received 625 g of the shell of the shrimp with a mass fraction of water of 80% (yield 125 g or 5% in terms of a.s.w.). The chemical composition of the dried shrimp shell sample is given in Table 3.

In a flask with a capacity of 3 l was loaded 1.5 l of a 4% solution of sodium hydroxide with a temperature of 20 ^o C and 600 g of wet shell of shrimp. The mixture was stirred for 1 h and the precipitate was centrifuged at 8000 rpm for 30 minutes. Then the precipitate of deproteinized shell was washed on the filter with water at a temperature of 80-90 ^o C to a pH of the filtrate of not more than 8.0.

In a flask with a capacity of 3 l was loaded 1.5 l of a 3.6% solution of hydrochloric acid with a temperature of 20 ^o C and deproteinized shell of the shrimp. The mixture was stirred for 30 minutes and the demineralized carapace was separated by filtration and washed on the filter with water at a temperature of 15 ^{° C.} until the filtrate had a pH of at least 5.0.

To completely remove proteins and discolor chitin, a second deproteinization of the precipitate was performed with a 4% sodium hydroxide solution at a temperature of 85-95 ^o C for 1 h. The chitin was washed with hot water until neutral and dried in an oven at a temperature of 60 ^o C.

 Received 34 g of dry chitin. Yield 1.36%.

 The chemical composition of dried chitin is given in table.3.

 Example 2

 Obtaining chitin and enzymatic protein hydrolyzate from shrimp fishing waste using hepatopancreas-raw king crab.

 2.5 kg of raw frozen shrimp fishing waste was thawed in air at room temperature, crushed on a homogenizer to a homogeneous mass with a shell particle size of not more than 3 mm. The crushed raw materials were charged into a 10 L flask with a mixing device. Poured 2.3 kg of water. Loaded 200 g of ground hepatopancreas raw king crab. Next, the hydrolysis, separation and purification of the hydrolyzate was carried out according to example 1.

 Received 420 g of dry hydrolyzate, completely soluble in water to a concentration of 5%. The yield of 16.8%. The chemical composition and amino acid composition of the hydrolyzate are shown in tables 3 and 4.

 Received 667 g of the shell of the shrimp with a mass fraction of water 82% (Yield 120 g or 4.8% in terms of a.s.w.). The chemical composition of the dried shrimp shell sample is given in Table 3.

 Getting chitin was carried out analogously to example 1.

 Received 33 g of dry chitin. Yield 1.32%.

 The chemical composition of dried chitin is given in table.3.

 Example 3

 Obtaining chitin and an enzymatic protein hydrolyzate from waste from the king crab using raw hepatopancreas.

 The enzymatic treatment was carried out analogously to example 2 using 2.5 kg of raw-frozen waste from the processing of king crab (carapace) and 200 g of hepatopancreas crab.

 Received 180 g of dry hydrolyzate, completely soluble in water to a concentration of 5%. The yield of 7.2%. The chemical composition and amino acid composition of the hydrolyzate are shown in tables 3 and 4.

 Received 1745 g of crab shell with a mass fraction of water of 65% (Yield 610 g or 24.4% in terms of a.s.w.). The chemical composition of the dried shrimp shell sample is given in Table 3.

 Getting chitin analogously to example 1.

 Received 135 g of dry chitin. Yield 5.4%.

 The chemical composition of dried chitin is given in table.3.

 Example 4

 Obtaining chitosan from wet chitin with short-term evacuation of the reaction mixture.

640 g of water were charged into two flasks with a capacity of 3 L and, with stirring, 800 g of sodium hydroxide each. 1440 g of a 55.6% solution were obtained. 200 g of crab chitin were loaded into the hot solution with a mass fraction of water of 80% (from Example 3). The flasks were closed and the second created a vacuum pressure of 0.9 kg / cm ² . After boiling the mixture after 5 minutes, atmospheric pressure was restored in the flask and deacetylation was continued with stirring at a temperature of 105 ^{° C.} for 30 minutes. In the first flask, deacetylation was carried out under the same conditions, but at atmospheric pressure.

After deacetylation was completed, the alkali solution was separated by filtration. Chitosan precipitates were washed with water at a temperature of 80-90 ^o C to a filtrate pH of not more than 8.0. The washed precipitates were dried in an oven at a temperature not exceeding 60 ^o C.

 Received 27 g of chitosan. The yield of chitosan from dry chitin was 67.5%.

 The chemical composition and properties of chitosan are given in table 5.

 As can be seen, the greatest vacuum effect is observed when comparing the index of insoluble substances, which is explained by the acceleration of the diffusion of the alkali solution to the inner zones of the particles of chitin particles.

 The present invention allows using a single cost-effective technology to utilize previously unused chitin and protein-containing raw materials used for processing and processing crustaceans: shrimp and crabs, crab hepatopancreas, while producing chitin / chitosan and enzymatic protein hydrolysates for microbiological nutrient media. It is also important that the proposed method allows to reduce the degree of pollution of wastewater with protein products after receiving chitin.

Claims (1)

A method of waste-free complex processing of chitin-containing raw materials, including obtaining a protein hydrolyzate from the feedstock by enzymatic hydrolysis and chitin from a chitin-containing precipitate with the first deproteinization, demineralization, second deproteinization and drying of the finished product, characterized in that the enzymatic hydrolysis of proteins the action of hepatopancreas, a raw Kamchatka crab or a complex enzyme preparation obtained from it , at a ratio of 1-10 / 10-200 g: 1 kg of raw material, the precipitate is separated, the protein hydrolyzate is purified by coprecipitation of lipids and insoluble substances by chitosan, the purified protein hydrolyzate is dried, upon receipt of chitin, the first deproteinization is carried out at a temperature of not more than 20 ^o С for 0 , 5-2.0 hours with stirring, the second at 90-98 ^o C for 0.5-2.0 hours with stirring, the precipitate is separated, the chitin is washed and dried or sent to obtain chitosan, performing deacetylation of wet chitin 20- 60% sodium hydroxide solution at a ratio of rast Op sodium hydroxide: wet chitin (20-60): 1 and 95-120 ^o C with occasional stirring for 30-90 min, and 5 min from the beginning is carried out in vacuo at a pressure of 0.5-1.0 kg / cm ² , at the end of the deacetylation process, the alkali solution is separated, the chitosan precipitate is washed and dried.

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