ES2362522A1 - Procedure for the obtaining of aromatic concentrates from subscribers of shellfish by extraction with supercritical or sub-critical fluids. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Procedure for obtaining aromatic concentrates from crustacean by-products by extraction with supercritical or subcritical fluids: Procedure for obtaining aromatic concentrates from by-products of the seafood processing industry, mainly crustaceans, by extraction with sub- or supercritical fluids, mainly carbon dioxide, with extraction pressures between 60 and 500 bar, extraction temperatures between 20 and 500 bar. And 80º c, separation pressures between 30 and 60 bar and separation temperatures between -20 to 30º c, wherein the extract containing the organic compounds responsible for the aroma is collected in an adsorbent food material, which is subsequently subjected to a lyophilization process or spray drying, after which a powdery, stable and odorless material is obtained at room temperature which contains the substances characteristic of the seafood aroma. (Machine-translation by Google Translate, not legally binding)

Description

Procedure for obtaining concentrates aromatic from seafood by-products by extraction with supercritical or subcritical fluids.

Field of the Invention

The present invention is included in the sector of food and / or food products obtained from the sea, in particular crustaceans, specifically, in the separation of organic compounds responsible for aroma, by extraction by solvents

State of the art

In recent decades, several have been proposed processes to obtain concentrates with aroma and flavor Seafood In 1970, Gray [Gray, R.D., Food Flavoring Composition. 1970] patented a process based on shells and fibrous material from which seafood is previously removed. The process requires the cleaning of the shells, removing the viscera residuals present, and wet milling of by-products for obtaining a paste that is subsequently acidified and subjected to spray drying to obtain particles with the aroma and desired flavor Gray's main objective was to obtain economically viable of a concentrate that will present the minimum Possible amount of moisture, stable for long periods of storage, and with good organoleptic characteristics. Do not However, in 1979, Henneberry and Idziak [Henneberry, G.O. and Idziak, E.S., Extraction of flavor and color shell shell waste. 1979] They found that this product had poor acceptability due to to the presence of residual shells and their high content in calcium. Therefore, they proposed another method based on the addition of proteolytic enzymes on a previously filtered paste to obtain water soluble extracts that are subsequently dried to get a powder extract with the aroma, flavor and color desired

In 1984, Noda et al . [Noda, M., Sakasai N., Someya S., Honda Y., Nobuhara A., Preparation of seasoning. 1984] prepared a fish-free dressing by enzymatic decomposition of different types of seafood and the addition of substances (eg: 2,6-dimethoxyphenol, guaiac or 3-methylguayacol) that provide smoked notes to the final product.

On the other hand, Oonishi and Satou [Oonishi, J. and Satou, K., Pulverization of aqueous extract of fish, shellfish and / or cattle meat. 1984] focused on obtaining a powdery material with the aroma and flavor of seafood, mixing a aqueous seafood extract with water soluble dextrins and subsequent lyophilization or spray drying. This treatment prevents moisture absorption, agglomeration, discoloration and development of odors while maintaining the delicate aroma of seafood.

In 1984, Nishikawa [Nishikawa, F., Preparation of natural seasoning. 1984] obtained a natural dressing, with a strong aromatic power, through a process consisting of grinding seafood cool until fine particles are added, add water and salt, adjust the pH of the mixture (optionally you can add protests), break down lipids and proteins through a process of enzymatic self-digestion, let the mixture react for a 7-30 days period, extract with hot water and desalt and concentrate by reverse osmosis.

This same author, in 1985 [Nishikawa, F., Preparation of seasoning extract. 1985], obtained a concentrate of low cost, with low salt content and with improved flavor and aroma. This process is based on the enzymatic breakdown of a soup of shellfish from which non-soluble solids and oils, to obtain low molecular weight substances, such as amino acids, etc. On the other hand, the substances responsible for the brown coloring formation in the extract, the components Bitters such as Mg, Ca, etc., and low ionic components Molecular weight are removed by electrodialysis, so that the proportion of components responsible for the aroma is increased and flavor. Subsequently, the soup is concentrated by a process of reverse osmosis and evaporation under vacuum of the solvent.

For their part, Okomura and Suzuki [Jiyouji, O. and Yasuko, S., Preparation of extract of shellfish meat. 1986] they obtained a seafood concentrate with excellent organoleptic characteristics by cooking shellfish, peeling and subsequently treating the broth obtained with a material adsorbent, such as activated carbon powder, heating with stirring, with subsequent cooling and separating the adsorbent solid by filtration. The filtrate was concentrated by evaporation under vacuum. obtaining a concentrated liquid with a solids content of the 65% This final product has excellent palatability and highlights the absence of bad smells like the smell of sea and flavors unpleasant as bitterness or astringency that presents the broth of original cooking.

In 1987 Yoshikawa [Yoshikawa, M., Production of fermented flavor. 1987] designed a fermentation process for Obtaining an aromatic concentrate. The process consists in doing react a shellfish extract with bacteria belonging to genus Lactobacillus, Streptococcus or Pediococcus, or by adding also yeasts belonging to the genus Saccharomyces and / or mold of Koji belonging to the genus Aspergillus.

In 1988, Ishii [Ishii, K., Clarification of fish and shellfish extract. 1988] obtained a stable concentrate and with excellent organoleptic characteristics, subjecting a soup of shellfish at a concentration stage followed by ultrafiltration or vice versa, with a final stage of ion exchange in both cases.

In 1989, Usui et al . [Usui K .; Ogawa M .; Takai K .; Sato T .; Tanaka M .; Serizawa I., Process for preparation of shellfish extract concentrate, and shellfish extract concentrate. 1989] observed that a conventional shellfish extract, particularly oyster, obtained by concentrating the residual broth in the canning (canning) processing industry, usually contains the components responsible for shellfish aroma and flavor (eg, glutamic acid ) or aroma-enhancing components (eg: glycogen), but also various black and brown colored substances that provide the extract, in addition to an unacceptable color in many products, bitter, irritating and spicy odors and a heavy and fatty flavor. These brown and black colored compounds are products of the Maillard reaction, produced by compounds containing the amino group, usually amino acids, and carbonyl groups, generally sugars. Maillard reactions involving reducing sugars cause a reduction in the nutritive value of the broth in the broth and deterioration of the flavor components. Therefore, these authors proposed to use adsorbents, formed mainly by an inorganic compound of magnesium of large surface area, to eliminate from the broths the precursor substances of these compounds of black and brown coloration, without substantially reducing the compounds responsible for the aroma and the flavor and nutrients present in the broth. Subsequently, the refined liquid is concentrated in a non-oxidizing atmosphere.

In 1994, Sakamoto [Sakamoto, K., Preparation of seasoning oil of crustacean. 1994] prepared a dressing consisting of a red-orange oil obtained from of seafood by-products, subjecting the materials to a frying, cooking, separation of oils and fats, addition, of an antioxidant agent and purification thereof. He result was an oil with a less intense smell than dressings commercial, but closer to the natural crustaceans and with the possibility of varying its organoleptic characteristics depending on of the frying conditions.

In 2003, Kuroda and Nishimura [Kuroda, M. and Nishimura, Y., Fish and shellfish extract improved in flavor and method for producing the same. 2003] obtained an extract of Seafood without fishy smell and improved flavor. The method developed consists of adjusting the pH of the extract between 3.5 and 4.8, remove insoluble products by filtration or centrifugation, adjust the pH of the filtrate between 5 and 7, add and mix 5-20% Kieselguhr and filter the mixture and / or add a sugar and dissolve it while stirring and then heat the mix between 100 and 150 ° C for 1 to 60 minutes.

In 2004, Sato and Yoshikawa [Sato, T. and Yoshikawa, H., Crustacean or shellfish flavor and food. containing the same 2004] proposed a simple method consisting of heat a mixture of shellfish or shellfish extract, amino acids and sugars, followed by a distillation of the product obtained. He obtained aroma and flavor had organoleptic characteristics that They reminded roast seafood.

In 2005, Kawasaki [Kawasaki, K., Method for producing flavor of crustacean. 2005] carried out the formulation of the aroma associated with crustaceans using materials Synthetic perfumery of different chemical nature to create a product with the natural aroma and flavor of crustaceans.

Hayakawa et al [Hayakawa, T. and Yamakazi, T., Smoked fish and shellfish flavor. 1993] and Hayashi et al . [Hayashi, M. and Sugimoto, K., Roasted fish and shellfish flavor. 1993] obtained an aroma of smoked and grilled fish and seafood, by extraction with carbon dioxide under subcritical and supercritical conditions mixed with cosolvent (mixture of water and alcohol), from different fish and shellfish than in most of the cases had been previously dried, broiled or baked, or smoked. The authors state that this technique avoids the problems presented by concentrates obtained through traditional methods such as steam distillation or extraction with organic solvents, such as the lack of certain organoleptic characteristics present in grilled fish or shellfish, low intensity, short durability and low palatability. The concentrate obtained was mixed with an adsorbent substance, homogenized and subsequently subjected to spray drying or lyophilization to obtain a powder with the desired aroma.

Description of the invention

The present invention proposes the obtaining of natural concentrates from by-products of the seafood processing industry, mainly exoskeletons. The process protected in this patent consists in the extraction of the compounds responsible for the most characteristic aroma and flavor of shellfish, especially crustaceans, using fluids under subcritical or supercritical conditions, especially pure carbon dioxide, on matrices constituted by by-products of the seafood processing industry, mainly shellfish shells. Unlike the proposal by Hayakawa et al [Hayakawa, T. and Yamakazi, T., Smoked fish and shellfish flavor. 1993] and Hayashi et al . [Hayashi, M. and Sugimoto, K., Roasted fish and shellfish flavor. 1993], in the present proposal no co-solvents are used, which makes the present process simpler since it avoids the use of organic solvents, and therefore their final separation of the obtained extracts.

The experimentation performed to optimize this process was carried out in a semi-pilot plant of extraction with supercritical or subcritical fluids, designed and Built in the Chemical Engineering Area of the University of Burgos, consisting of a diaphragm pump (Lewa) membrane metal and refrigerated head, a stainless steel extractor AISI-316 2 liter capacity, a separator easy opening of half a liter, a cold equipment that allows the recirculation of carbon dioxide and different baths thermostatic, resistors, and valves that allow fixing the desired pressure and temperature in each of the process phases (see Figure 1).

The process of the invention, for obtaining aromatic concentrates from seafood by-products by extraction with sub- or supercritical fluids without Co-solvents, includes the steps of:

- Recovery of industry by-products seafood processor, especially from different cookers Crustacean species, consisting primarily of the Exoskeleton of the animal.

- Mechanical pre-treatment of by-products to facilitate the extraction of the compounds responsible for aroma And the taste of seafood.

- Extraction of the compounds responsible for aroma and taste of seafood through continuous contact with the compressed fluid (sub- or supercritical).

- Continuous recirculation of the fluid to the process extraction once separated the compounds responsible for aroma and the taste of seafood in a separator by reducing the pressure and solvent temperature.

- Perform the previous stages of extraction and recirculation for long enough to remove the components of interest

- Final recovery of compounds interest collected in the separator by depressurization at low temperature, to release the fluid (e.g., carbon dioxide carbon) minimizing as far as possible the loss of volatile during said depressurization.

Solvent separation (for example, CO_ {2}) for recirculation occurs in the separator. This separation can be achieved by reducing pressure and temperature causing precipitation of dissolved compounds in the extractor. The performance of this separation process is can favor including in the separator different substances foodstuffs that act as adsorbent materials retaining the volatile compounds of interest.

The process parameters studied, for the obtaining aromatic concentrates from by-products of shellfish by extraction with sub- or supercritical fluids without Co-solvents are: extraction pressure between 60 and 500 bar, extraction temperature between 20 and 80ºC, pressure of separation between 30 and 60 bar, separation temperature from -20 to 30 ° C and final recovery temperature of the compounds of interest of -10 to 5ºC. The influence of all of them has been studied in the quantity and quality of aromatic concentrates obtained.

In case the extracts are not collected on an adsorbent, it is added to the extract later. A final lyophilization stage of the adsorbent mixture + extract provides a stable aromatic concentrate that shows its organoleptic characteristics when it is dissolved in its end use

The final stage of drying can also be carried carried out by spray drying, resulting in a aromatic concentrate with appearance and final characteristics different.

The aromatic concentrates obtained are analyzed by gas chromatography coupled to spectrometry of masses for the detection of the compounds, after concentration thereof by dynamic solid phase extraction (SPDE, Solid Phase Dynamic Extraction). A gas chromatograph was used (Agilent 6890N) coupled to a mass spectrometer (Agilent 5973i) and an automatic sampler (CTC-Combi-Pal). The SPDE technique has It has been used as a concentration technique for analytes interest for further analysis, as other techniques that come being used, such as evaporation at atmospheric pressure or vacuum evaporation, lead to the partial loss of these Compounds due to their high volatilities.

In the aromatic concentrates obtained have identified more than a hundred compounds responsible for cooked crustacean aroma, among which are aldehydes, alcohols, ketones, nitrogen compounds (pyrazines, pyridines, amines, idols), furans, esters, hydrocarbon terpenes saturated and unsaturated aliphatics, aromatic hydrocarbons and organo-sulfur compounds (sulfides, thiazoles).

Brief description of the figures

This descriptive report is complemented, with a set of figures, illustrative of the preferred example, and never limiting the invention.

Figure one

Figure 1 describes the scheme of operation of the extraction plant with supercritical fluids Which consists of:

one.

Source of the extraction fluid, being able to be a CO2 deposit.

2.

Heat exchanger that works like subcooler

3.

Pressurization system of the fluid, being able to be a pump or compressor, to raise fluid pressure up to the process values, which may be higher than the critical fluid pressure.

Four.

Heater of the current, to raise the fluid temperature up to the process value, this may be higher than the critical fluid temperature.

5.

Solid extractor, which is used to contain the solid to be extracted and through which the fluid circulates compressed.

6.

Pressure control element, usually valve upstream pressure control.

7.

Heat exchanger, is used to adjust the fluid temperature and therefore the process temperature in the separator.

8.

Separator, can be gravitational, cyclonic or evaporative and may or may not contain any agent adsorbent.

9.

Separator pressure control element, usually Be an upstream pressure control valve.

10.

Fluid condenser, it is usually a heat exchanger whose job is to cool the fluid below of its dew temperature, although it may be preceded by a compressor to increase the dew temperature of the fluid.

eleven.

Lung for fluid recirculation.

The system can be composed of several extractors (item 5) that can be worked in series or in parallel and They can be loaded and unloaded alternately. Parts 7, 8 and 9 can be repeated several times in order to fractionate the extract obtained.

Figure 2

Figure 2 presents the effect of temperature of extraction in the number of aldehydes, alcohols or ketones extracted.

The influence of temperature on these processes is complex. An increase in temperature, although it causes decrease in solvent density, may be responsible for increased solvation power due to the increase that occurs in  the vapor pressure of the solute.

Figure 2 shows that the number of aldehydes and ketones extracted increases with the temperature of extraction; however the effect of temperature on Alcohols seems to be the opposite. This behavior can be explain based on the higher volatility they normally present aldehydes and ketones against alcohols since the hydrogen bonding is more difficult in a carbonyl group than in a hydroxyl group.

Embodiment of the invention Preamble

The main by-products of the industry Seafood processing are broths, exoskeletons and viscera. These By-products have generated great interest in recent years due to the presence of a large group of substances of interest in the food industry among which are polysaccharides (such as chitin), dyes (such as astaxanthin), antioxidants, substances responsible for the taste and aroma of seafood and fatty acids polyunsaturated

The food industry demands concentrates of Seafood aroma and flavor for use in soups, sauces, broths, etc. At present, the natural concentrates obtained directly from seafood through physical processes that do not alter olfactory perception and Original taste.

An economically attractive way of obtaining said concentrates is by extracting the compounds responsible for aroma and flavor, from the by-products generated in the seafood processing industry. In this regard, a large number of volatile compounds have been identified in seafood processing by-products, such as crab [Chung, HY and Cadwallader, KR, Volatile components in Blue Crab (Callinectes sapidus) meat and processing by-product . Journal of Food Science, 1993. 58 (6): p. 1203-1207], the crayfish [Baek, HH and Cadwallader, KR, Volatile Compounds in Flavor Concentrates Produced from Crayfish-Processing Byproducts with and without Protease Treatment . Journal of Agricultural and Food Chemistry, 1996. 44: p. 3262-3267] or the prawn [Mandeville, S., Yaylayan, V. and Simpson, B., GC / MS Analysis of Flavor-Active Compounds in Cooked Commercial Shrimp Waste . Journal of Agricultural and Food Chemistry, 1992. 40 (7): p. 1275-1279]. So these by-products can be an important source in the recovery of the compounds responsible for the aroma of these species.

The aroma of fresh seafood has been defined as sweet, with unmistakable vegetable notes, often accompanied by a metallic note and a fishy smell of varying intensity [Spurvey, S., Pan, BS and Shahidi, F., Flavor of shellfish, in Flavor of Meat, Meat Products and Seafoods , Shahidi, F., Editor. 1998, Springer. p. 159-196], The main compounds responsible for the aroma of fresh crustacean are aldehydes and unsaturated alcohols. On the other hand, the aroma of cooked seafood is characterized by the presence of numerous compounds of very different chemical characteristics, such as alcohols, aldehydes, ketones, furans, pyrazines, saturated and unsaturated aliphatic hydrocarbons, aromatic hydrocarbons, organosulfur compounds, nitrogen compounds, esters and terpenes, in certain proportions. This fact makes obtaining a characteristic aromatic concentrate from a complex matrix, such as a food, a complex problem.

Extraction with carbon dioxide supercritical or subcritical, compared to conventional techniques such as extraction with organic solvents, adsorption or simultaneous distillation-extraction, offers important advantages since it allows to operate with an agent of separation that does not cause any residue in the final product, allows to operate in a wide range of pressure conditions and extraction temperature, making it possible to adjust the solvent power of carbon dioxide, and find out what the conditions are suitable for the extraction of the compounds responsible for seafood aroma and allows operating at low temperatures, which prevents degradation of those compounds that are thermolabile. On the other hand, the conditions of separation of the extract and the Solvents are variables to consider, because the higher part of the aromatic concentrate components present high vapor pressures, which greatly hinders the complete separation of carbon dioxide from compounds interest. If the separation pressure is not low enough, many of the compounds could remain in the gas phase giving rise at low process performance or profile modification aromatic of the final concentrate.

For these reasons, the use of carbon in supercritical or subcritical conditions as an agent of separation has become a common practice for the recovery of aromas from many different food matrices.

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Description of an embodiment

Exoskeletons were extracted from sea ox in the pilot plant of the Engineering laboratory Chemistry of the University of Burgos. 600 grams of raw material and extraction in pressure ranges and extraction temperature of 150-200 bar and 25-75 ° C respectively. The pressure in the separator It remained in the range of 30-50 bar. The Extraction was performed with solvent recirculation during a 60-120 minute period.

The extract obtained in the separator presented Two phases; an aqueous phase and a colored oil phase red-orange, due to the co-extraction of lipids, mostly acids unsaturated fatty acids (70%), and carotenoid pigments present in Certain species of seafood. The amount of organic phase increased With the extraction pressure. The influence of temperature on these processes is more complex since an increase in temperature decreases the density of the solvent, and therefore its power solvent, but the vapor pressure of the solute increases, and therefore its solubility Figure 2 shows that the number of aldehydes and ketones extracted increases with the temperature of extraction; however the effect of temperature on Alcohols seems to be the opposite. This behavior can be explain based on the higher volatility they normally present aldehydes and ketones against alcohols since the hydrogen bonding is more difficult in a carbonyl group than in a hydroxyl group.

The presence of fatty acids in the extracts causes the formation of compounds that provide the extract unwanted organoleptic characteristics during storage. These compounds formed from oxidation of the lipid fraction are essentially saturated hydrocarbons (mostly branched alkanes and compounds derived from cyclohexane), unsaturated hydrocarbons, saturated aldehydes and short chain fatty acids.

The aromatic profile of the extracts is determined by gas chromatography with detection by mass spectrophotometry, after concentrating the compounds contents in the headspace of the samples to be analyzed using SPDE. The analysis of the two phases included in the EFSC plant separator led to the identification of more than 150 compounds responsible for the aroma of crustaceans. The biggest part of the identified compounds was in the phase watery The compounds that appear in greater proportion in the head space of the extracts obtained are aldehydes, in concrete unsaturated aldehydes like (E) -2-pentenal, (E) -2-hexenal, (E, E) -2,4-heptadienal, (E) -2-octenal or (E, Z) -2,6-nonadienal, which They provide good organoleptic characteristics to the extracts. Also saturated aldehydes (hexanal, heptanal, octanal, nonanal and decanal) and aromatic aldehydes (benzaldehyde, phenylacetaldehyde) They are in high proportions.

Saturated alcohols present in the highest part of the high threshold cases of olfactory perception in phase aqueous, therefore they hardly contribute to the final quality of abstract. For their part, unsaturated alcohols have values much less so his contribution is very remarkable. Likewise these substances are associated with fruity and sweet aromas In the extracts, mainly alcohols were found unsaturated and phenols, highlighting as major compounds in the most of the extracts 1-penten-3-ol, 1-octen-3-ol, and (5Z) -1,5-octadien-3-ol. Phenols are compounds that usually occur in Seafood by-products formed from thermal degradation of lignin and provide a scent of wood, smoked and spicy.

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Ketones, meanwhile, provide an aroma Sweet, floral and fruity in crustaceans. Extracts contain large number of these compounds, presenting aliphatic ketones (saturated and unsaturated) aromatic ketones and diketones. Be found as major compounds ketones that have five and eight carbon atoms in its molecule, as is the case with 1-penten-3-one, 2,5-pentanedione, 1-octen-3-one and 3,5-octadien-2-one.

They have also been found in smaller quantities heterocyclic compounds such as pyrazines, pyridines, furans and organosulfur compounds. Most of these compounds are not It is part of the aroma of ox by-products of Sea employees in this work as starting material. These Compounds are formed when by-products are subjected to a heat treatment as Maillard reactions take place. The Maillard reactions, are important in the formation of the aroma of Cooked food They are reactions between peptides and sugars reducers that lead to the formation of volatile compounds, which include heterocyclic compounds previously cited. Pyrazines are important compounds to the time to evaluate the overall aroma of the extract obtained, as they provide to the global aroma of the extract notes of cooked potato and nuts. In the extracts, mainly alkylpyrazines have been found, except for the case of 2-acetylpyrazine. He 2,5-dimethylpyrazine compound is the only one heterocycle present in the starting material and is found as Major component of this type of compounds in the extracts. Pyridine when found in low concentrations in extracts brings good organoleptic characteristics to them. As soon as to the furans, 2-pentilfuran and 2- (1-pentenyl) furan are the compounds majority in this group. Both compounds are formed from the autoxidation of linoleate, linoleic acid ester that represents 1% of the fatty acids present in the oil co-extracted together with the aqueous extract. First of them gives the extract organoleptic characteristics unwanted (rancidity). However, the second provides notes of licorice extract. Organo-sulfur compounds are generally found in small quantities. However, they have thresholds very low olfactory perception, which makes them substances very potent flavorings and contribute significantly to global aroma of the extract obtained. Within this type of compounds have been identified aliphatic sulphides, such as the dimethyl trisulfide (previously found in many crustaceans heat treated as crayfish byproducts) that contributes with a green aroma, or heterocycles, more specifically thiazoles as 2-acetylthiazole and 1,2-benzothiazole, thermally formed during process through the reaction of sulfur amino acids, especially cysteine, with reducing sugars (reactions of Maillard) Also noteworthy is the compound 2-acetylthiazole, which has a detection limit very small olfactory (1.3 ppb) and contributes with almond notes, cereal, cookie and corn to the final extract.

Saturated hydrocarbons hardly contribute to the global aroma since they have thresholds of olfactory perception very high. Only the presence of 2,6,10,14-tetramethylpentadecane that contributes with floral and green tones to the final aroma.

Terpenes are present as compounds derived from the animal's own diet. These compounds They are found in small proportions in the extract, highlighting d-Limonene as the majority compound.

The esters are present in the seafood by-products, contributing with a sweet smell and fruity However, the presence of these compounds is minority

In this extract, maltodextrins were dissolved that adsorb the compounds responsible for aroma and flavor contained in the extracts. The mixture was later lyophilized obtaining a powdery, stable and odorless material at room temperature. The dissolution of this material provided the Same olfactory footprint as the initial extract.

Claims (13)

1. Procedure for obtaining aromatic concentrates from shellfish by-products, by extraction with sub- or supercritical fluids and without co-solvents, characterized in that the extraction pressure is between 60 and 500 bar, the extraction temperature; between 20 and 80 ° C, the separation pressure; between 30 and 60 bar, and the separation temperature; between -20 and 30ºC. 2. Method for obtaining aromatic concentrates according to claim 1, characterized in that it comprises the steps of:

2.1.

Recovery of by-products from the seafood processing industry, of different cookers crustacean species, consisting of the exoskeleton of the animal.

2.2.

Mechanical pretreatment of by-products to facilitate the extraction of compounds responsible for aroma and flavor of seafood.

2.3.

Compound Extraction responsible for aroma and taste of seafood through contact continuous with the sub- or supercritical compressed fluid.

2.4.

Continuous fluid recirculation at extraction process once the responsible compounds are separated of aroma and flavor of seafood in a separator by reduction of solvent pressure and temperature.

2.5

Perform stages 2.3 and 2.4 during long enough to extract the components of interest.

2.6.

Final recovery of compounds of interest collected in the separator by depressurization to low temperature, from -10ºC to 5ºC, to release the fluid minimizing as much as possible the loss of volatiles during said depressurization

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3. Procedure for obtaining aromatic concentrates according to claims 1 and 2, characterized in that step 2.4. It is carried out with continuous recirculation of carbon dioxide to the extraction process, once the compounds responsible for aroma and taste of shellfish are separated in a separator, by adsorption in food adsorbents, such as dextrins, maltodextrins, cyclodextrins, starch, gum arabic , gelatin or casein, at low temperature. 4. Method for obtaining aromatic concentrates according to claims 1 and 2, characterized in that a food adsorbent, such as dextrin, maltodextrin, cyclodextrin, starch, gum arabic, gelatin or casein, is added to the material obtained in the separator and is It performs a subsequent lyophilization of the mixture to obtain a powdery, stable, odorless material at room temperature and containing the substances characteristic of the aroma of shellfish. 5. Method for obtaining aromatic concentrates according to claims 1 to 3, characterized in that the material, mixture of extract and food adsorbents, obtained in the separator, is lyophilized in order to obtain a stable, odorless, pulverulent material at room temperature and containing the substances characteristic of the aroma of shellfish. Method for obtaining aromatic concentrates according to claims 1 and 2, characterized in that a food adsorbent, such as dextrin, maltodextrin, cyclodextrin, starch, gum arabic, gelatin or casein, is added to the material obtained in the separator and is Performs a subsequent spray drying of the mixture to obtain a powdery, stable, odorless material at room temperature and containing the substances characteristic of the aroma of shellfish. 7. Method for obtaining aromatic concentrates according to claims 1 to 3, characterized in that the material, mixture of extract and food adsorbents, obtained in the separator, is subjected to spray drying or in order to obtain a stable, powdery material , odorless at room temperature and containing the substances characteristic of the aroma of shellfish.