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    • 专利摘要:
    Procedure for obtaining an isolated tannic extract of grape, obtained tannic extract and its uses. A method for obtaining an isolated tannic extract of grape from grape seeds is provided. The procedure comprises: preparation of grape seeds as source of tannins; preparing an aqueous solution of a polyphenol solubilizing agent selected from urea, a compound containing the group so3 and sodium hydroxide at a concentration of 1% to 15% by weight; in an autoclave reactor, carry out a single extraction; separation and direct concentration to give the isolated extract. The invention also relates to the obtained tannic extract. The new tannic extract isolated from grape seeds comprises a mixture of tannins and non-tannins, whose composition provides the extract with improved antioxidant and light fastness properties. The tannic extract isolated from grape seeds also comprises a dye. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2644166A1
    申请号:ES201630673
    申请日:2016-05-24
    公开日:2017-11-27
    发明作者:Anna BACARDIT DALMASES；Luis OLLÉ OTERO；Sílvia SOROLLA CASELLAS；Concepció CASAS SOLÉ
    申请人:Universitat Politecnica de Catalunya UPC；
    IPC主号:
    专利说明:

    DESCRIPTION
    PROCEDURE FOR OBTAINING A TANIC EXTRACT ISOLATED FROM GRAPE, TANIC EXTRACT OBTAINED AND ITS USES
    The present invention relates to a process for obtaining a tannic extract isolated from grapes. In particular, the invention relates to an aqueous extraction process for obtaining a tannic extract that focuses on the source of selected tannins and the type of polyphenol solvent used in the extraction stage.
    The invention also relates to the tannic extract obtained by the steps defined in the process. In particular, a new tannic extract isolated from grape seeds 10 is obtained comprising a mixture of tannins and non-tannins, whose composition provides the extract with improved antioxidant and light fastness properties. The tannic extract isolated from grape seeds also comprises a dye.
    The invention also relates to the use of the tannic extract isolated from grape seeds as a tanning agent, antioxidant agent and / or coloring agent in the tanning, food, cosmetic and / or pharmaceutical industries.
    Background of the invention
    The current situation in the technology of extraction of vegetable tannins for the tanning industry is based on aqueous phase extraction processes. The tannic extracts obtained are used in the tanning industry by reacting them with the tissue 20 of the animal skin, preserving its flexibility and making it resistant to rot.
    The plant tannic extracts currently used in the tanning industry are mainly the Quebracho extract, the Mimosa extract, the Chestnut extract, or the Tara extract, all of them of plant origin originating from forest trees in South America, or from South Africa that have been cultivated and felled for this purpose. 25
    As a source of tannins, wood, bark, leaves or other parts of a crushed tree have been used as raw material to date. After crushing, the resulting crushing is mixed in an alcoholic or aqueous solution and extraction is carried out at a certain pressure and temperature to extract the tannins from the raw material. The liquid fraction resulting from the extraction contains the tannins of interest. The separation of the solid fraction from the liquid fraction is carried out by sedimentation, optionally followed by a chemical treatment and, finally, the tannins are concentrated to obtain the plant tannic extract in a liquid state. When it is desired to obtain the solid state extract, an atomization is also carried out.
    Different variants of this methodology have been proposed, for example, using cold water or hot water, with atmospheric pressure or higher.
    Tannins are polyphenols, in general, soluble in water, of molecular weight between 500 and 3,000, with a different composition according to their origin, although with an approximation to the formula: C14H14O11. Tannins have a characteristic odor, a color that varies from yellowish to dark brown, all have a bitter taste, are astringent, exposure to light obscures them and react with ferric salts forming bluish black compounds that are used as raw material for get dyes The main chemical characteristic is its ability to precipitate proteins and make them resistant to decomposition, which is why they are useful as tanning agents.
    Spanish patent application ES2197821 describes a process for obtaining a vegetable tannic extract in the aqueous phase. The source of tannins used is the grape pomace, the grape pomace comprising a crushed mixture of rasp, skin and seed. fifteen
    The procedure includes the following stages:
    i) use, as a source of tannins, of the grape marc;
    ii) preparation of a solution of a sulfonating agent in an amount of water;
    iii) simultaneously, mixing the solution prepared in stage ii) with the grape pomace from stage i) in a reactor at a certain pressure and temperature to extract the 20 tannins;
    iv) solid-liquid separation; Y
    v) purification and concentration of the extract obtained.
    According to the description of the ES2197821A1 patent, the nature of the tannins obtained from the grape pomace is of the condensed (catechemic) type and the concentration of these is linked to the number of extractions made. A filtration and pressing is described after the solid-liquid separation stage by discharge of the extracted liquid and then a sedimentation and decantation stage after filtration and before carrying out the purification and concentration. Thus, in order to obtain acceptable extraction yields it is necessary to carry out additional steps and use different equipment which makes it difficult to scale on an industrial scale.
    Therefore, the method described in ES2197821 is not feasible on an industrial scale, partly because it requires filtering followed by purification to isolate the product of interest, and partly because the yield of tannin extraction depends on the number of extractions made , the greater the number, the more tannins are extracted, in addition to requiring different equipment. 5
    It would therefore be desirable to provide a process for obtaining a plant extract, which was environmentally friendly, scalable on an industrial scale, simple and easy, with good yields to give a tannic extract soluble or dispersible in cold water of Enhanced antioxidant and light fastness properties. In addition, an extract of plant origin with coloring properties is desirable. 10 Description of the invention
    In order to solve the problems posed by the state of the art, the present invention focuses on the source of selected tannins and the type of polyphenol solubilizing agent used in the extraction stage. The proper processing of both, with certain stages and conditions provides a new extract isolated from the grape.
    Thus, in a first aspect, the object of the invention is to provide a process for obtaining a tannic extract isolated from the grape comprising the use of a source of tannins, the preparation of an aqueous solution of a polyphenol solubilizing agent and a step of extracting tannins in a reactor comprising the source 20 of tannins and the aqueous solution prepared at a pressure and temperature, which is characterized by the fact that:
    - the source of tannins are grape seeds,
    - the polyphenol solubilizing agent is selected from urea, sodium hydroxide and a compound containing the SO3 group and its concentration in the aqueous solution is between 1 and 15% by weight with respect to the weight of grape seeds, and
    - the extraction stage is carried out in an autoclave at a pressure between 1 and 6 atmospheres and at a temperature between 80 and 160 ° C, and 30
    - optionally, concentration of the extract by evaporation to obtain the concentrated isolated tannic extract and / or spray dried to obtain the isolated solid state tannic extract.
    In the present invention, the term "grape seed" means the seed or pipe separated from the grape berry and dried. Therefore, the calculated grape seed weights are dry weights. The shapes of the pips or pipes can be ovoid, spherical, crushed or circular and with different sizes. Its hardness ranges from soft to crispy. 5 The nugget or pipe is inside the berry of the grape, and is responsible for being the way of reproduction of the vine.
    Preferably, the grape seeds are used whole, that is to say, seeds or grape pipes without crushing or grinding are preferred. The authors of the present invention have found better properties in the extract obtained and better process yields using whole grape seeds.
    In the present invention, the term "polyphenol solubilizing agent" means an agent capable of reacting with the carboxylic groups present in the polyphenols. In the present invention, said polyphenol solubilizing agent is selected from urea, a compound containing the group SO3 or sodium hydroxide. The compound containing group 15 SO3 is an inorganic acid or salt containing group SO3 such as sulfuric acid, oleum, sulfamic acid, sodium sulphite, sodium bisulfite or sodium metabisulfite.
    In a preferred embodiment, the polyphenol solubilizing agent is urea.
    Preferably, the concentration of polyphenol solubilizing agent in the aqueous solution is between 2% and 8% by weight with respect to the weight of grape seeds. twenty
    Preferably, the weight ratio between grape seeds and water to prepare the solution is 1: 1. However, this ratio can vary from 0.5: 1 to 1: 4.
    Also preferably, the extraction step is carried out in an autoclave reactor at a temperature between 100 ° C and 130 ° C and at a pressure between 2.5 and 3.5 atmospheres. Even more preferably, the extraction step is carried out at a temperature of 120 ± 2 ° C, and a pressure of 3 atmospheres. These extraction conditions are maintained for a period of time between 1 and 2 hours. The liquid extract obtained can be used directly for tanning the skin.
    In the present invention, the term "autoclave" means a reaction chamber. This reaction chamber is normally constructed of stainless steel, and is designed to work at high pressures in order to carry out a reaction, cooking or steam sterilization. A high pressure, of up to approximately 6 atmospheres, allows the water to reach temperatures above 100 ° C.
    Thus, in a first aspect of the present invention a simple and easy process is provided, which only requires an autoclave reactor and a single extraction stage to obtain good yields compared to the state of the art that requires filtering and purification, In addition to several extractions to obtain acceptable performance. 5
    Advantageously, the process for obtaining the isolated tannic grape seed extract of the first aspect provides high yields, 63% and 80.3% compared to 42.1% of the prior art.
    An environmentally friendly procedure is provided, which reuses grape seeds, by-products or grape residues, which are available in an available manner and are easy to obtain due to their geographical concentration without cutting down trees or importing parts of the mimes.
    It provides a scalable procedure on an industrial scale, uses shorter process times and does not require filtration, sedimentation, decantation, or purification, undesirable stages in an industrial scale process. fifteen
    The process according to the first aspect of the invention is also designed to, if desired, reuse the cleaning water of the autoclave reactor so that water consumption can be reduced to 80% of total water consumption. Advantageously, the equipment cleaning water is capable of being reused as a component in the preparation of the aqueous solution of the polyphenol solubilizing agent in a new extraction.
    Advantageously, the process for obtaining an isolated grape extract according to the first aspect of the invention reduces the energy consumption necessary for obtaining the extract because the costs of stages for the extraction and concentration of tannins from the grape seed are lower than not requiring additional separation stages or purification stages of the extract obtained.
    Surprisingly, a new tannic extract isolated from the grape is provided with the process according to the first aspect of the present invention.
    Thus, in a second aspect, the present invention relates to a tannic extract isolated from the grape obtained in accordance with the first aspect of the invention comprising a mixture of pure hydrolysable tannins, pure condensed tannins and non-tannins that include acid Gallic.
    Vegetable extracts are mainly composed of four fractions, which are:
    a) Non-Tannins: It is the fraction of low molecular weight, less than 500, that do not have tanning power, but that contributes to improve the solubility of tannin, increase the penetration rate and separate the fibers from the skins.

    - Taninos hidrolizables o pirogálicos: Son los que en presencia de ácidos 15 fuertes en caliente, se hidrolizan en glucosa y en ácido gálico o ácido elágico, teniendo gálotaninos o elágitaninos. Los primeros se extraen de las agallas, Quercus infectoria y Rhus semisalata, de sus hojas del sumac, Rhus coriaria y de la tara Caesalpinia spinosa, mientras que los elagitánnicos están presentes en la madera del roble, Quercus robur, Quercus petraea y Quercus 20 alba, del castaño, Castanea vesca y Castanea Dentae y del mirabolá, Terminalia chebula.
    - Taninos condensados o catequínicos: Los taninos condensados no se descomponen con los ácidos y se caracterizan por la capacidad gradual de formar polimerizados insolubles denominados flovácenos. Se diferencian 25 entre proantociánicos que por hidrólisis ácida liberan antocianinas y otros compuestos, y profistenídicos que están presentes en las extracciones de las maderas del quebracho, Schinopsis balasae y Schinopsis lorentzii, de la mimosa, Acacia mearnsi y Acacia Mollissima, y en las extracciones de las hojas de gámbir, Uncaria gambi. 30
    - Se dan taninos cuya estructura es una mezcla de taninos hidrolizables y condensados. b) Tannins: they are water-soluble polyphenols of a molecular weight between 5,500 and 3,000, with a different composition according to their origin, but an approximation to their formula is: C14H14O11. Tannins have a characteristic odor, a color that varies from yellowish to dark brown, all have a bitter taste, are astringent, exposure to light obscures them in color and react with ferric salts giving bluish black compounds that are used to make dyes The main chemical characteristic is its ability to precipitate proteins and make them resistant to decay, which is what determines their use as a tanning agent. Tannins are classified according to their structural characteristics in:
    - Hydrolysable or pyrogallic tannins: They are those that in the presence of hot strong acids, are hydrolyzed into glucose and gallic acid or ellagic acid, having gallotannins or elagitannins. The former are extracted from the gills, Quercus infectoria and Rhus semisalata, from their sumac leaves, Rhus coriaria and the Caesalpinia spinosa tara, while elagitannics are present in oak, Quercus robur, Quercus petraea and Quercus 20 alba , of the chestnut, Castanea vesca and Castanea Dentae and of the mirabolá, Terminalia chebula.
    - Condensed or catechin tannins: Condensed tannins do not decompose with acids and are characterized by the gradual ability to form insoluble polymerized so-called flovacenes. There are 25 differences between proanthocyanins that, by acid hydrolysis, release anthocyanins and other compounds, and profistenides that are present in the extractions of the woods of the quebracho, Schinopsis balasae and Schinopsis lorentzii, of the mimosa, Acacia mearnsi and Acacia Mollissima, and in the extractions of the gambir leaves, Uncaria gambi. 30
    - Tannins are given whose structure is a mixture of hydrolysable and condensed tannins.

    c) Insoluble: It is the fraction of molecular weight greater than 3,000, corresponds to polyphenols complexed with very astringent carbohydrates that due to their high molecular weight they find it difficult to penetrate the skin and are fixed superficially. Its presence is not desirable and in fact they are found in extracts manufactured under very aggressive conditions.
    d) Humidity: Water percentage of each extract. 5
    Surprisingly, the combination of different types of polyphenols present in the extract obtained in accordance with the first aspect of the invention give it the same light fastness properties and improved antioxidant properties with respect to the plant extracts of the prior art.
    Unexpectedly, when urea is used as a polyphenol solubilizing agent in the method of obtaining the extract, the tannic extract obtained comprises a dye.
    Therefore, the isolated tannic extract of grape seeds obtained using urea as a polyphenol solubilizing agent comprises a mixture of pure hydrolysable tannins, pure condensed tannins, non-tannins that include gallic acid and a dye. fifteen
    The authors of the present invention have performed UV-Vis spectrophotometry tests (350-800nm) of a sample of the extract obtained using urea as a polyphenol solubilizing agent to prepare the aqueous solution that has been compared with the scanning of a conventional brown dye, in particular Dark Brown CA appearing at 472.85 nm, and the scan results show a maximum in a sample of the extract at 352.8 nm, 20 Absorbance 2.70A, within the UV region (see Fig. 4).
    The authors of the present invention have corroborated the presence of the dye with an HPLC analysis of a sample of the extract (see Fig. 5).
    Thus, the invention also provides an extract comprising an azo dye, wherein said azo dye is exempt or with a detection limit of less than 30mg / kg of 25 prohibited aromatic amines, which makes it suitable for use as a tanning agent, agent antioxidant and coloring agent in the tanning, food, cosmetic and / or pharmaceutical industries, as desired.
    In the present invention "dye free or free of prohibited aromatic amines" is understood that said aromatic amines are not detected with a detection limit of 30 mg / kg.
    In a third aspect, the invention relates to the use of the tannic extract according to the first or second aspect of the invention as a tanning agent, antioxidant agent, or coloring agent in the tanning, food, cosmetic or pharmaceutical industry.
    An added advantage of the new extract is its multifunctionality since it is applicable as an antioxidant, coloring agent and tanning agent.
    In addition, the extract of the invention can also be used in the combined tanning chrome-5 vegetable or as a retanning agent in skins and leathers already tanned to chromium that need a post-tanning treatment in order to modify characteristics such as strength, thickness or flexibility .
    FOOD USE
    In the wine industry, tannins are responsible for sensory characteristics as important as color, body, astringency and bitterness. These compounds have their origin in the raw material with which the wine is made, but also in the oak wood used in the aging in barrels or directly applied to the wine. In the case of oak barrels, there are tannins known as hydrolysable tannins (their two classes, elagitannins and gallotannins), to differentiate them from those of grapes where there is a greater concentration of condensed tannins, these are importantly responsible for aspects positive for wine, such as body and coloring stability in red wines. The precipitation properties of tannins are used to clean or clear wines or beer.
    Advantageously, with the tannic extract obtained from grape seed according to the invention, an extract is obtained with a composition that makes it useful for food use, for example, in the wine industry.
    INDUSTRIAL USE
    In industry, tannins are used especially for tanning skins, thanks to their ability to transform proteins into products resistant to decomposition. In this tanning process certain tannins are used, the most commonly used are those from acacia, chestnut, oak, pine or bastard. They are also used in the textile industry for their ability to react with ferric salts, which give rise to black-bluish products suitable for dyes. They are also used as mordants for the application of dyes in tissues, coagulants of 30 gums, or preparations for papers or silks.
    Advantageously, with the tannic extract obtained from grape seed according to the invention an extract is obtained with a composition that makes it useful for industrial use, for example, in the tanning industry.
    MEDICINAL USE
    In medicine they are prescribed for their astringent, hemostatic, antiseptic and toning action. The aforementioned property of coagulating the albumin of the mucous membranes and tissues, 5 creates a dry, insulating and protective layer that reduces irritation and pain on the skin. Externally, preparations based on tannin-rich drugs, such as decoctions, are used to stop small local hemorrhages; in inflammations of the oral cavity, colds, bronchitis, burns, hemorrhoids, etc. Internally, they are useful against diarrhea, intestinal cooling and vesicular conditions. Tannins are also useful as a poison in case of poisoning by vegetable alkaloids. Brief description of the figures
    For a better understanding of how much has been exposed, some drawings are attached in which, schematically and only by way of non-limiting example, a practical case of realization is represented. fifteen
    Figure 1 shows the chromatogram obtained by reverse phase high performance liquid chromatography (HPLC) of the extract obtained according to the first and second aspect of the invention, in which the source of tannins are whole grape seeds and the solubilizing agent. of polyphenols used in the extraction step is sodium metabisulfite according to Example 1 of the invention. twenty
    Figure 2 shows the chromatogram obtained by reverse phase high performance liquid chromatography (HPLC) of an extract obtained according to the first and second aspect of the invention, in which the source of tannins are whole grape seeds and the agent Polyphenol solubilizer used in the extraction step is urea according to Example 2 of the invention. 25
    Figure 3 shows the chromatogram obtained by reverse phase high performance liquid chromatography (HPLC) of the extract obtained according to reference Example 3, in which the source of tannins is pomace of the crushed grape and the polyphenol solubilizing agent used in the extraction stage is sodium metabisulfite.
    Figure 4 shows the scan graph of the extract obtained from a sample of the extract 30 according to Example 2 of the invention (■ ■ ■) compared to the scan of a conventional brown dye (▬▬) obtained between 350-800 nm by UV-Vis spectrophotometry.
    Figure 5 shows the chromatogram obtained by HPLC-DAD at 500 nm of a sample of the extract obtained according to Example 2 of the invention in the range between 200-800 nm.
    Figure 6 shows a comparative test of the strength of artificial light according to the IUF 402 standard where the stability of the extract obtained in accordance with Example 1 and Example 2 of the invention is appreciated. For a better understanding of what has been stated, some examples are attached in which, schematically and only by way of non-limiting example, specific embodiments of the invention are represented. 10 Examples EXAMPLE 1: Tannic extract isolated from grape seeds Chemical extraction
    For 100 kg of dried grape whole seed, 5 kg of sodium metabisulfite and 100 liters of distilled water were used. The aqueous solution contained 5% sodium metabisulfite. fifteen
    All components were introduced into an autoclave reactor and aqueous extraction was carried out in the autoclave reactor maintaining the temperature at 120 ° C and pressure 3 atmospheres for 1 hour.
    After the indicated time, an isolated tannic extract of grape seeds in a liquid state suitable for skin tanning was obtained. twenty EXAMPLE 2: Tannic extract isolated from grape seeds Chemical extraction
    For 100 kg of dried grape whole seed, 5 kg of urea and 100 liters of distilled water were used. The aqueous solution contained 5% urea.
    All components were introduced into an autoclave reactor and aqueous extraction was carried out in the autoclave reactor maintaining the temperature at 120 ° C and pressure 3 atmospheres for 1 hour.
    After the indicated time, an isolated tannic extract of grape seeds in a liquid state suitable for skin tanning was obtained.

    Reference EXAMPLE 3: Tannic extract isolated from grape marc Chemical extraction
    For 200 kg of pomace, 2 kg of sodium metabisulfite and 400 liters of distilled water were used.
    All components were introduced into an autoclave reactor and aqueous extraction was carried out in the autoclave reactor maintaining the temperature at 136 ° C and 5 atmospheres of pressure for 3 hours.
    After the indicated time, the tannic extract isolated from the pomace was obtained.
    ESSAYS
    Chromatography of the extracts obtained according to Examples 1 to 3
    The extracts obtained in examples 1 to 3 were analyzed by high performance column chromatography with reverse phase separation. An Xbridge Phenyl type column was used. For chromatographic analysis, a 1:25 aqueous solution of the 5 extracts obtained in the examples was carried out. Subsequently, the extracts were filtered to 0.45 µm for analysis. 25 µl of the extract was injected. The chromatogram capture wavelength was 271.1 nm. See Figures 1 to 3 corresponding respectively to Examples 1 to 3.
    For the analysis, a new spectrum library was generated in which the 10 spectra of the different compounds present in samples of commercial tannins from Mimosa, Quebracho, Tara and Castaño were incorporated. The spectra of 10 commercial patterns of polyphenols of different chemical natures that include condensed or catechic types and those of hydrolysable or galotannin types were also incorporated. A comparison of the compounds identified in the extracts obtained according to Example 1, Example 2 and Reference Example 3 was carried out.
    Table 1 below lists the compounds identified in the isolated tannic grape seed extract according to Example 1:
     Peak  Tr (min.) Identification Area% Area / Total Area
     one  2.97 Gallic Acid Pattern 590.723 16.1
     2  3.46 Catechin Tannin of Quebracho 1 43.598 1.2
     3  3.87 Mimosa catechin tannin 1 51,787 1.4
     4  4.17 Catechin tannin. (Same chromophore as Procyanidin B2) 753,881 20.5
     5  5.93 Catechin Tannin. (Same chromophore as (+) - Catechin) 62,630 1.7
     6  6.54 Catechin tannin from Mimosa 2 55,427 1.5
     7  8.07 Catechin tannin from Mimosa 3 193.423 5.3
     8  8.91 Catechin Tannin. (Same chromophore as Procyanidin B2) 124,261 3.4
     9  11.71 Catechin Tannin. (Same chromophore as (-) -Epicatechin) 92,394 2.5
     10  11.96 Catechin tannin - hydrolysable. (Same chromophore as (-) -Epigalocatequin gallate) 32,164 0.9
     eleven  12.88 Catechin-hydrolysable tannin. (Same chromophore as (-) -Epicatequin gallate) 138,372 3.8
     12  13.63 Catechin tannin from Mimosa 4 26,330 0.7
     13  13.83 Gallic Tannin of the Tara 1 38,722 1.1
     14  14.67 Catechin-hydrolysable tannin. (Same chromophore as (-) -Epigalocatequin gallate) 60,524 1.6
     fifteen  15.99 Pattern (-) - Epicatechin 38,685 1.1
     16  16.25 Catechin tannin. (Same chromophore as (-) - Epicatechin) 6,683 0.2
     17  17,01 Tannin derived from gallic acid 46,040 1.3
     18  18.57 Catechin-hydrolysable tannin. (Same chromophore as (-) - Epicatequin gallate) 22,905 0.6
     19  19.07 Catechin-hydrolysable tannin. (Same chromophore as (-) - Epigalocatequin gallate) 63,283 1.7
     twenty  21.78 Pattern (-) - Epicatequin Gallate 23,363 0.6
     twenty-one  33.17 Catechin Tannin of Quebracho 2 502.689 13.7

    Table 2 below shows the compounds identified in the isolated tannic grape seed extract according to Example 2:
     Peak  Tr (min.) Identification Area% Area / Total Area
     one  2.97 Gallic Acid Pattern 842.937 12.2
     2  4.39 Catechin tannin. (Same chromophore as (-) - Epicatechin) 11,218 0.2
     3  13.79 Gallic Tannin of the Tara 1 42,495 0.6
     4  16.25 Pattern (-) -Epicatechin 14,799 0.2
     5  17.00 Gallic Tannin of Tara 2 35,618 0.5
     6  20.87 Ellagic Acid 26,598 0.4
     7  33.20 Catechin Tannin of Quebracho 2 5,452,782 79.0

    It is noteworthy that the compounds identified in the isolated 5 grape seed tannic extract of both Example 1 and Example 2 include a mixture of different types of tannins comprising pure hydrolysable tannins, pure condensed tannins and non-tannins that include gallic acid .
    In addition, in one embodiment, the tannic extract isolated from grape seeds comprises a mixture of pure hydrolysable tannins, pure condensed tannins, type 10 catechin-hydrolysable tannins and non-tannins that include gallic acid.
    The combination of the different types of tannins and the presence of gallic acid give the extract its improved properties compared to the properties of the state of the art extracts. In addition, the extract may also contain a dye that gives it a multifunctionality that has not been previously described in the state of the art.
    Table 3 below lists the compounds identified in the isolated tannic extract of grape marc according to reference Example 3:
     Peak  Tr (min.) Identification Area% Area / Total Area
     one  2.39 Catechin Tannin of Quebracho A 619.151 13.1
     2  2.56 Catechin Tannin of Quebracho B 921.371 19.5
     3  3.05 Catechin Tannin of Quebracho C 58,790 1.2
     4  4.42 Catechin tannin. (Same chromophore as Procyanidine B2) 97,276 2.1
     5  5.3 Mimosa catechin tannin 1. 91.454 1.9
     6  6.44 Catechin tannin-hydrolysable. (Same chromophore as (-) - Epicatechin gallate) 186,980 4.0
     7  13.09 Mimosa catechin tannin 2 14,589 0.3
     8  15.1 Gallic Tannin of the Tara 1 81,810 1.7
     9  16.77 Mimosa 3 Catechin Tannin 3 29,581 0.6
     10  19.94 Ellagic acid 45.466 1.0
     eleven  33.03 Catechin Tannin of Quebracho 2 244.369 5.2

    The following Table 4 is a summary table of the content and types of tannins and non-tannins of the extracts obtained according to Examples 1 to 3:
     Example 1 Example 2 Reference Example 3
     Tannins  % Total Area / Area% Total Area / Area% Total Area / Area
     Catechins  52.1 79.2 36.4
     Hydrolysable  2.3 1.1 1.7
     Catechins - Hydrolysable  8.6 0 4.0
     Total  63.0 80.3 42.1

     No tannins  % Area / Total area% Area / Total area% Area over global
     Gallic acid  16.1 12.2 0
     Ellagic acid  0 0.4 1.0
     Catechins  1.7 0.2 7.7
     Total  17.8 12.8 8.7

     Not identified  % Area / Total area% Area / Total area% Area over global
     Total  19.2 6.9 49.2
     5
    The percentage of catechin tannins obtained from grape seed is in one embodiment almost double (Example 1) than in the prior art (Reference Example 3) and more than double (Example 2) than in the state of the technique (Reference Example 3). The percentage of non-tannins that includes gallic acid is similar in both examples 1 and 2 according to the invention while this does not appear in reference example 3. The 10 non-tannins in spite of not having tanning power, their presence contributes to improving the solubility of the tannin, increasing the penetration rate and separating the fibers from the skins. Therefore, an adequate balance between tannins and non-tannins in the isolated grape seed extract is responsible for the improved properties of the extract obtained in accordance with the invention. Said equilibrium is maintained in the extract obtained in Example 5 2 which further comprises the azo dye. UV-Vis scanning of the extract obtained in Example 2 The dye used as reference was Dark Brown CA. The extract obtained according to Example 2 was compared with the reference dye by the UV-Vis scanning dye comparison method obtained between 350-10800 nm by UV-Vis spectroscopy. The graph obtained is represented in Figure 4.
    In said Figure 4 a single maximum corresponding to the reference dye Dark Brown CA can be seen at 472.85 nm (▬▬) and a maximum in the extract obtained according to Example 2 at 352.8 nm (■ ■ ■) which is in the UV region. Global chromatogram of the extract obtained in Example 2 15
    A new HPLC analysis of the extract obtained in Example 2 was carried out by acquiring said chromatogram in the range between 200-800 nm.
    In the global chromatogram of the extract, only one peak of great magnitude was identified (1), with a spectrum similar to that obtained by UV-Vis (which represents the overall absorption of all the polyphenols present in the sample). See Figure 5. 20
    It was verified by the spectrum of the compound of Tr = 33.2 (1) that one of the polyphenolic compounds present in the isolated tannic grape seed extract has an absorption in the visible visible range. This fact favors the degree of fixation that said compound experiences with respect to the tanned skin with the isolated tannic extract of grape seed obtained according to Example 2. 25
    Light fastness
    To determine the light fastness of the extracts obtained in accordance with the present invention, a comparative test of the solidity of the artificial light according to the IUF 402 standard was carried out. See Figure 6, where 1 is tanned leather with Mimosa extract, 2 is tanned leather with Chestnut extract, 3 is tanned leather with Quebracho extract, 4 is tanned leather 30 with Tara extract, 5 is tanned leather with grape seed extract with sodium metabisulfite (Example 1), 6 is tanned leather with grape seed extract with urea (Example 2).
    The test results confirm that the characteristics of the tanned skin with the isolated grape seed extract according to the invention, Examples 1 and 2, with and without dye, respectively, exhibit improved light stability. It is surprising that the presence of dye in the extract, see column 6, does not interfere with the light stability of the tanned skin even after 36 hours (last row). Therefore, the light fastness of the isolated tannic extract of grape seeds according to the invention has improved light fastness with the state of the art extracts.
    Determination of certain aromatic amines derived from azo dyes (ISO 10 17234: 2015) in tanned skin using the isolated tannic extract of grape seed according to Example 2
    It is general knowledge for a person skilled in the art to comply with ISO 17234-1: 2015 (Second edition 2015-04-01) to determine the presence of certain prohibited aromatic amines in azo dyes that makes them suitable or not for their use in 15 general.
    This test analyzes the presence of certain analytes, that is, certain aromatic amines, with a detection limit of 30 mg / kg of a tanned sample in accordance with said ISO 17234-1: 2015 standard. As a result of said analysis, the authors of the present invention confirm that the dye is exempt from the prohibited aromatic amines, 20 aromatic amines listed in Table 5. Next, the prohibited aromatic amines are listed in accordance with said ISO 17234 standard -1: 2015 in Table 5 that follows:
     Forbidden aromatic amines:  RESULTS
     4-aminobiphenyl (CAS-No .: 92-67-1)  Not detected (1)
     Benzidine (CAS-No .: 92-87-5)  Not detected (1)
     4-chloro-o-toluidine (CAS-No .: 95-69-2)  Not detected (1)
      2-naphthylamine (CAS-No .: 91-59-8)  Not detected (1)
     o-amino azotoluè (CAS-No .: 97-56-3)  Not detected (1)
     5-nitro-o-toluidine (CAS-No .: 99-55-8)  Not detected (1)
     4-chloraniline (CAS-No .: 106-47-8)  Not detected (1)
     4-methoxy-m-phenylenediamine (CAS-No .: 615-05-4)  Not detected (1)
     4,4'-diaminodiphenylmetà (CAS-No .: 101-77-9)  Not detected (1)
     3,3'-dichlorobenzidine (CAS-No .: 91-94-1)  Not detected (1)
     3,3'-dimethoxybenzidine (CAS-No .: 119-90-4)  Not detected (1)
     3,3'-dimetibenzidine (CAS-No .: 119-93-7)  Not detected (1)
     4,4’-methylene di-o-toluidine (CAS-No .: 838-88-0)  Not detected (1)
     p-cresidine (CAS-No .: 120-71-8)  Not detected (1)
     4,4'-methylene-bis- (2-chloraniline) (CAS-No .: 101-14-4)  Not detected (1)
     4,4'-oxidianiline (CAS-No .: 101-80-4)  Not detected (1)
     4,4'-thiodianiline (CAS-No .: 139-65-1)  Not detected (1)
     o-toluidine (CAS-No .: 95-53-4)  Not detected (1)
      4-methyl-m-phenylenediamine (CAS-No .: 95-80-7)  Not detected (1)
     2,4,5-Trimethylaniline (CAS-No .: 137-17-7)  Not detected (1)
     o-anisidine (CAS-No .: 90-04-0)  Not detected (1)
     4-aminoazobenzè (CAS-No .: 60-09-3)  Not detected (1)
     2,4-xylidin (CAS-No .: 95-68-1)  Not detected (1)
     2,6-xylidin (CAS-No .: 87-62-7)  Not detected (1)


















    (1) No prohibited aromatic amines have been detected in the azo dye.
    Detection limit <30mg / kg. Characteristics of the grape seed extract obtained
    The nature of the tannins is a mixture of pure condensate type (catechin) and pure hydrolyzable type (pyrogenic);
    The extract comprises non-tannins that include gallic acid; It is believed that its presence is responsible for a better antioxidant action and a better light fastness.
    The extract is soluble in cold aqueous medium;
    It has application as a tanning agent for skins;
    It has application as an antioxidant agent in food, cosmetics and pharmacy;
    It has application as a coloring agent in tanning, food, cosmetics and pharmacy; 10
    It has improved light fastness, between the Chestnut 2 extract and the Tara 4 extract;
    The color of the tanned product is similar to that obtained with the Chestnut extract.
    Although reference has been made to a specific embodiment of the invention, it is apparent to one skilled in the art that the described process is susceptible of numerous variations and modifications, and that all the mentioned details can be substituted by other technically equivalent ones. , without departing from the scope of protection defined by the appended claims.
    权利要求:
    Claims (11)
    [1]
    1. Procedure for obtaining a tannic extract isolated from the grape comprising the use of a source of tannins, the preparation of an aqueous solution of a polyphenol solubilizing agent and a step of extracting tannins in a reactor comprising the source of tannins and the aqueous solution at a pressure and temperature, characterized by the fact that:
    - the source of tannins are grape seeds,
    - the polyphenol solubilizing agent is selected from urea, sodium hydroxide and a compound containing the SO3 group and its concentration in the aqueous solution is between 1 and 15% by weight with respect to 10 weight of grape seeds, and
    - the extraction stage is carried out in an autoclave at a pressure between 1 and 6 atmospheres and at a temperature between 80 and 160 ° C, and
    - optionally, concentration of the extract by evaporation to obtain the concentrated isolated tannic extract and / or spray dried to obtain the isolated solid state tannic extract.
    [2]
    2. Method according to claim 1, wherein the grape seeds are used whole, without crushing or grinding.
    [3]
    3. The method according to claim 1, wherein the polyphenol solubilizing agent 20 is urea.
    [4]
    4. Process according to any of the preceding claims, wherein the concentration of polyphenol solubilizing agent in the aqueous solution is between 2% and 8% by weight with respect to the weight of grape seeds.
    [5]
    5. Method according to any of the preceding claims, wherein the weight ratio between grape seeds and water to prepare the solution is between 0.5: 1 and 1: 4.
    [6]
    Method according to any of the preceding claims, wherein the extraction stage is carried out at a temperature between 100 ° C and 130 ° C, and at a pressure between 2.5 and 3.5 atmospheres. 30
    [7]
    7. Method according to any of the preceding claims, where once the process is completed, a step of cleaning the equipment with water is carried out which is capable of being reused for the preparation of a new aqueous solution of the polyphenol solubilizing agent.
    [8]
    8. Tannic extract isolated from the grape obtained by the method defined according to any one of claims 1 to 7, wherein the tannic extract isolated from grape seeds 5 comprises a mixture of pure hydrolysable tannins, pure condensed tannins and non-tannins that include acid Gallic.
    [9]
    9. Tannic extract according to claim 8, wherein using urea as a polyphenol solubilizing agent in the process of obtaining the extract, the obtained tannic extract further comprises a dye. 10
    [10]
    10. Tannic extract according to claim 9, wherein the dye is an azo dye free of prohibited aromatic amines.
    [11]
    11. Use of the tannic extract according to any of claims 7 to 10 as a tanning agent, antioxidant or coloring agent in the tanning, food, cosmetic or pharmaceutical industry. fifteen

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    同族专利:
    公开号 | 公开日
    CN109952110A|2019-06-28|
    EP3463410A1|2019-04-10|
    WO2017203429A1|2017-11-30|
    ES2644166B1|2018-09-24|
    US20200121752A1|2020-04-23|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP1044260A1|1997-12-30|2000-10-18|Ferco|Method for obtaining grape tannin, resulting tannin and uses|
    DE19827179A1|1998-06-18|1999-12-23|Edmone Roffael|Extraction of tannin-containing plant-based raw material|
    ES2197821A1|2002-06-18|2004-01-01|Invest De Las Ind Del Curtido|Vegetable tannic extract for tanning of hides consists of pressed grape peel in an aqueous sulfonation agent solution, autoclaved and purified|
    ES2443547A1|2012-07-19|2014-02-19|Universidade De Santiago De Compostela|Polyphenol extract from white-grape residue|
    US5912363A|1997-08-29|1999-06-15|Interhealth Nutraceuticals|Method for extraction of proanthocyanidins from plant material|
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    ES201630673A|ES2644166B1|2016-05-24|2016-05-24|PROCEDURE FOR OBTAINING A TANIC EXTRACT ISOLATED FROM GRAPE, TANIC EXTRACT OBTAINED AND ITS USES|ES201630673A| ES2644166B1|2016-05-24|2016-05-24|PROCEDURE FOR OBTAINING A TANIC EXTRACT ISOLATED FROM GRAPE, TANIC EXTRACT OBTAINED AND ITS USES|
    PCT/IB2017/053035| WO2017203429A1|2016-05-24|2017-05-23|Process for obtaining a tannin extract isolated from grapes, tannin extract obtained and uses thereof|
    CN201780043044.4A| CN109952110B|2016-05-24|2017-05-23|Method for obtaining tannin extract isolated from grapes, tannin extract obtained and use thereof|
    US16/303,915| US20200121752A1|2016-05-24|2017-05-23|Process for obtaining a tannin extract isolated from grapes, tannin extract obtained and uses thereof|
    EP17728269.6A| EP3463410A1|2016-05-24|2017-05-23|Process for obtaining a tannin extract isolated from grapes, tannin extract obtained and uses thereof|
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