RU2429726C2 - Method for preservation of shell-containing wastes of complex processing of krill - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: method envisages dispersion of shell-containing wastes of complex processing of krill, their blending with a preserving agent, packing the produced mixture with subsequent closing. Blending with the preserving agent is performed in the interelectrode space of a diaphragmless electrolyser simultaneously with production of the preserving agent by way of treatment of water solution of an electrolyte with initial concentration 0.6-1.2% till the mixture pH is 12.6-12.8.

EFFECT: invention allows to preserve shell-containing wastes without aggressive reagents utilisation.

4 cl

Description

The invention relates to food and fish processing industries, in particular to methods of preservation using chemical preservatives, and can be used to save shell-containing wastes from complex processing of krill for the subsequent production of chitin and chitosan from them, which are widely used in various industries and medicine.

There is a method of preserving shell-containing wastes (PSO) of crab processing with salt (Semenova N.K., Kim G.N., Safronova T.M., Ignatyuk L.N. Preservation of raw crab shells with sodium chloride // New perspectives in the study of chitin and chitosan / Fifth All-Russian Conf. - M.: VNIRO Publishing House, 1999. - P.66-68; Semenova N.K., Gavrilchenko M.M., Safronova T.M., Ignatyuk L.N. Conservation of carapace waste from the processing of crab with table salt // Scientific works of Dalrybvtuz. - 1998. - Issue 11. - S.129-134), in which whole shells of carapace and overflow belly whether salt directly in the container, and crushed mixed with a preservative, and then packaged. The concentration of table salt was 24%. To fill the voids and isolate from contact with atmospheric oxygen, the material was poured with an isotonic preservative solution in the ratio for whole PSO - 1: 2.0-1: 2.5, for crushed ones - 1.20-1: 1.25.

The disadvantage of this method is the significant consumption of fresh water to remove the preservative by rinsing the PSO before producing chitin from them to avoid increasing the mass fraction of minerals in the latter, as well as limiting the shelf life of PSO due to an increase in the content of sodium ions in chitosan as the storage period of PSO increases . In addition, salt has a stabilizing effect on the carotenoids of the shell and their relationship with chitin and chitosan, which also reduces the quality indicators of these polymers, due to its incomplete purification from mineral salts and carotenoid components.

There is also a method of preserving shell-shaped wastes of crustacean processing, in which the PSO is first mixed with 10% hydrochloric acid (HCl), Packed in a container and added with 2.5% HCl to the ratio of PSO: preservative ≤0.20-0.25 (Gavrilchenko M.M., Safronova T.M., Semenova N.K. Chemical preservation as a way to save shell-containing wastes // University Students - the Free Economic Zone "Nakhodka": Abstracts / First Inter-University Scientific Conf. - Find: IT and B, 1997. - P.128-129; Semenova N.K. Development of canning technology chitin-containing waste processing crustaceans: Abstract of a thesis ... Candidate of Technical Sciences - Vladivostok, 1999. - 31 c)......

The disadvantage of this method is the unsatisfactory quality indicators of chitin obtained from PSO, due to the hydrolytic destruction of chitin and a decrease in its molecular weight during storage of PSO.

The closest technical solution to the claimed one, taken as the closest analogue to the prototype, is a method for preserving shell-shaped shellfish processing waste, in which PSO is first mixed with 10% sodium hydroxide (NaOH), Packed in a container and added with 2.5% NaOH to the ratio of PSO: preservative ≤0.20-0.25 (Gavrilchenko M.M., Safronova T.M., Semenova N.K. Chemical preservation as a way to save shell-containing waste // University Students - Free Economic Zone Nakhodka: Abstract / First Interval scientific conference - Nakhodka: IT and B, 1997. - P.128-129; Semenova NK Development of technology for preserving chitin-containing wastes of crustacean processing: Abstract of thesis ... candidate of technical sciences. - Vladivostok, 1999. - 31 s.).

The disadvantage of the prototype is the complexity of the canning process, due to the use of an aggressive chemical reagent - a highly concentrated alkali solution, which necessitates the accumulation of crystalline alkali in large quantities on ships and coastal enterprises and significantly increases the risk of production and worsens its ecology. In addition, alkali does not provide effective conservation (long-term storage) of PSO that was in the air before the beginning of the conservation process at 0 ± 2 ° C for more than 4 days, and under normal conditions - more than 1 day.

The aim of the invention is to increase safety and simplify the process of conservation of shell-containing wastes of complex processing of krill with a simultaneous increase in its effectiveness for the subsequent production of better chitin and / or chitosan.

At the same time, the task of creating a more effective and environmentally friendly technology for preserving the PSO has been solved, which can significantly increase the safety of production with a simultaneous increase in the quality indicators of the finished target product produced from PSO (chitin or chitosan), including in ship conditions.

This is achieved by the fact that in the proposed method for preserving shell-shaped wastes of complex processing of krill, including dispersing them, mixing with a preservative, packing the resulting mixture in a container with its subsequent corking, unlike the prototype, mixing with a preservative is carried out in the interelectrode space of a diaphragmless electrolyzer simultaneously with its (preservative) obtaining by processing an aqueous electrolyte solution with an initial concentration of 0.6-1.2%, while the process is carried out until the pH of the mixture 12.6-12.8.

In the proposed method, in contrast to the known ones, preservation of PSO is carried out not with alkali or acid, but with an electrochemically activated solution obtained by electric processing of a low-mineralized (0.6-1.2%) aqueous electrolyte solution in a diaphragmless electrolyzer, and mixing PSO with a preservative is carried out simultaneously with the process of it (preservative) obtaining by the above processing in a diaphragmless electrolyzer of a mixture of PSO with an aqueous solution of an electrolyte.

The electrolyte used is mainly sodium chloride (NaCl), sodium sulfate (Na ₂ SO ₄ ) or a mixture thereof and sodium hydroxide (NaOH) with a total concentration of 0.6-1.2% in fresh water.

Processing PSO in the form of a mixture with an aqueous solution of the electrolyte in the cell is carried out at a ratio of solid and liquid phases in the range of 1: 2-1: 10.

Carapace-containing wastes are crushed, mixed with an aqueous solution, for example, Na ₂ SO ₄ with NaOH, with a total initial concentration of 0.6-1.2% and treated with an electric current in the interelectrode space of the diaphragmless electrolyzer until the pH of the medium reaches 12.6-12.8 .

Then the contents of the electrolyzer are centrifuged and / or filtered to remove excess preservative to achieve a ratio of solid and liquid phases in the range of 1: 1-1: 2.

After filtering, a mixture of PSO with a preservative is placed in a container and sealed.

Thus, preservation (mixing with a preservative) of PSO is carried out directly in the interelectrode space of a diaphragmless electrolyzer with an electrochemically activated solution formed during the action of an electric current on the electrolyte solution during the mixing process.

New in the invention is that the use of electrochemically activated low-mineralized aqueous solutions of electrolytes instead of a highly concentrated solution of alkali or acid increases safety and simplifies the process of preserving PSO.

More effective preservation of PSO is carried out due to the fact that electrochemically activated electrolyte solutions, in contrast to chemical preservatives, are stronger antiseptics, the bactericidal effect of which is due not only to the alkalinity of the medium, but also to the presence of valence-unsaturated particles (radicals) in their composition, which have increased reactivity, and a complex of strong oxidizing agents synthesized at the anode. Depending on the type of electrolyte, the material of the electrodes, and the potential, the electrochemically activated solution contains atomic oxygen, hydrogen peroxide, ozone, chlorine, etc., which, in contact with the cell, damage the cell membranes and destroy microorganisms, spores, etc.

Another important feature of the proposed method is the implementation of the main technological process (processing PSO preservative) in the interelectrode space of the electrolyzer directly under the influence of electric current.

Electric current is a strong oxidizing agent, therefore, when the PSO is processed in the electrolyzer, due to the additional action of the current and a polarizing uniform electric field, the antimicrobial effect of the electrochemically activated solution on the PSO is enhanced.

A more complete isolation of protein, lipids, and carotenoids from PSO during storage and improvement of the quality indicators of the finished target product (chitin or chitosan) produced from PSO are carried out due to the fact that in activated solutions water molecules have additional degrees of freedom due to broken ones due to electric fields of hydrogen bonds, which leads to an increased ability of activated solutions to penetrate into the intermolecular spaces of various substances, including biological membranes To increase hydration shells around individual ions or molecules, as well as increase the solubility of sparingly soluble compounds, enhance the extraction activity of solutions.

The proposed method allows preserving as fresh shell-containing krill waste (not more than 4 days of storage at 0 ± 2 ° C and not more than 1 day under normal conditions), obtained as a result of its complex processing - mechanized cutting through aeration, centrifugation, pressing krill in ship conditions, with satisfactory initial microbiological and organoleptic characteristics, and krill PSO, which were in the air before the canning process at 0 ± 2 ° C for more than 4 days, and at normal Under ideal conditions - more than 1 day, with initial microbiological indicators close to the upper permissible limit for PSO, but satisfactory organoleptic indicators.

The use of diaphragmless electrolyzers eliminates the danger of air pollution by chlorine-containing gaseous emissions and does not require the organization of a special ventilation circuit.

The technology is intended for use both in ship conditions and in conditions of coastal enterprises.

The process is easy to control and manage.

The proposed method was implemented in laboratory conditions using a diaphragmless electrolyzer. The cathode material is stainless steel, the anode material is platinum.

The method is as follows.

The raw materials used were shell-containing krill wastes remaining after pressing the muscle tissue from it.

PSO krill is crushed to a particle size of 3-5 mm, and then mixed with an aqueous solution of NaCl and NaOH with a total concentration of 0.6-1.2% in a ratio of 1: 2-1: 10. The minced salt mixture is fed into the interelectrode space of a diaphragmless electrolyzer (or mixed directly in the electrolyzer) and treated with an electric current density of 300-600 A / m ² until the pH of the medium reaches 12.6-12.8. After electric processing, the mixture of PSO with a preservative is filtered through a large-pore nylon filter to achieve a ratio of solid and liquid phases in the range of 1: 1-1: 2, then it is packed in a container and the container is closed.

The limits of the parameters and modes of the technological process are established experimentally; rational and recommended values are given in the description.

Thus, the proposed method differs from all known technical solutions in this field, realizing a fundamentally new approach to the conservation of shell-containing wastes of complex processing of krill, using their treatment with electric current in non-diaphragm electrolyzers in the form of a mixture with a low-saline aqueous electrolyte solution.

The proposed electrochemical method of preserving PSO in comparison with the known one allows them to be preserved more efficiently and without the use of concentrated aggressive chemicals, as well as to store PSO, the storage time of which before preservation at 0 ± 2 ° C is more than 4 days, and under normal conditions - more than 1 day.

The milder sparing conditions of conservation (the absence of aggressive media), the simultaneous effect on the PSO of an alkaline environment, the oxidation-reduction potential, the flow of charged particles and the electric current itself allow one to obtain target products (chitin and / or chitosan) with high functional and consumer properties.

A significant decrease in the concentration of aggressive chemicals significantly improves the environmental safety of the canned food production process for integrated processing of krill.

Claims (4)

1. A method of preserving the shell-containing wastes of complex processing of krill, including dispersing them, mixing with a preservative, packing the resulting mixture in a container with its subsequent corking, characterized in that mixing with a preservative is carried out in the interelectrode space of a diaphragmless electrolyzer simultaneously with its (preservative) preparation by processing an aqueous electrolyte solution with an initial concentration of 0.6-1.2%, while the process is carried out until the pH of the mixture reaches 12.6-12.8. 2. The method according to claim 1, characterized in that as the electrolyte, alkali metal salts are used: sodium chloride, or sodium sulfate, or sodium hydroxide. 3. The method according to claim 1 or 2, characterized in that the treatment of the shell-containing waste in the form of a mixture with an aqueous solution of the electrolyte is carried out at a ratio of solid and liquid phases in the range of 1: 2-1: 6. 4. The method according to claim 3, characterized in that before packing the resulting mixture of shell-containing waste with a preservative, the excess preservative is removed until the ratio of solid and liquid phases in the range of 1: 1-1: 2 is reached.