EP2776514A1

EP2776514A1 - Method for producing milk protein nanoparticles

Info

Publication number: EP2776514A1
Application number: EP12801468.5A
Authority: EP
Inventors: Anke Domaske
Original assignee: QMILCH IP GmbH
Current assignee: QMILCH IP GmbH
Priority date: 2011-11-12
Filing date: 2012-11-12
Publication date: 2014-09-17
Also published as: WO2013068598A1; WO2013068598A4; US20150024430A1

Abstract

The invention relates to milk protein nanoparticles produced according to a polymerization method in which at least one protein, which is obtained from milk and which can be thermally plasticized, is plasticized using a plasticizing agent, such as for example, water or glycerol at temperatures between room temperature and 140 °C, subjected to mechanical stress and subsequently retreated, for example, in the top down or bottom up method to form nanoparticles.

Description

Process for the preparation of milk protein nanoparticles

Methods for producing polymer nanoparticles are described in the literature and known to the person skilled in the art.

Japanese Patent 20090280148 (akiko Aimi) describes casein-based nanoparticles that are stable in the acidic range and that can be prepared with another active ingredient without the use of surfactants and synthetic polymers having a controllable size. However, the casein is dissolved in a basic, aqueous medium between pH 8 and pH 11 in a buffer medium or ethanol. Although the preparation of a casein-based biopolymer and the detection by photometric evaluation of the nanoparticles has been described, there is no description with respect to industrial production. A post-treatment of the corresponding suspension to achieve an economically useful product is not described.

German patent PCT / EP2007 / 052320 (BASF SE) "Process for the preparation of polymeric nanoparticles" comprises semisynthetic protective colloids, including casein, in which case the polymer product is obtained starting from polymerizable monomers using light energy. Absorber, UV treatment and the necessary photoinitiator as a chemical compound that releases free radicals under the influence of light.Photo initiators are indispensable in UV treatment, because they ensure the chemical crosslinking process under the UV lamp EU directive already with a share of 2.5% in the recipe, the tree fish symbol is a labeling requirement and must be disposed of in hazardous waste.

Also in all other literatures sufficient protein-based nanoparticles are described, however, all these literatures use crosslinking agents such as glutaraldehyde or PEG, which are demonstrably assigned to the allergens.

The use of nanoparticles presented so far shows in numerous investigations possible harmful environmental and harmful aspects of nanotechnologies, such as the inclusion of the particles in the organism via the respiratory tract, the skin and the mouth, even in already on the market products such as cosmetics and food additives.

Considerations for the disposal of nanoparticles are still provided with a question mark. When creating disposal guidelines, it must be considered whether the particles are free or bound to a matrix, whether they are water soluble or not, whether they disintegrate or aggregate. Therefore, possible risks from synthetically based polymer nanoparticles, including the manufacturing auxiliaries and additives, are not excluded. The aim should be to produce nanoparticles as far as possible with biogenic products and to favor biodegradable polymers.

The invention is based on the invention to avoid the disadvantages mentioned above and to produce nanoparticles preferably from renewable raw materials and preferably without the addition of acrylates and fossil raw materials. In addition, it is likewise an issue of the invention that the nanoparticles have a water content. To impart moisture resistance.

The invention is intended in particular to reduce the processing time and the use of chemicals, wherein the nanoparticles are preferably and largely to be produced from renewable or biodegradable raw materials. At the same time, water and energy consumption are to be reduced and productivity increased.

The object is achieved by a method according to the main claim: The present invention is directed to nanoparticles prepared by a continuous or discontinuous process of a composition comprising destructured milk proteins, biodegradable thermoplastic polymers and plasticizers.

In this case, at least one milk-derived protein or alternatively also a bacterium-produced protein is plasticized together with a plasticizer at temperatures between room temperature and 140 ° C under mechanical stress.

The invention is based on the finding that the milk proteins and in particular casein and its derivatives can be plasticized and polymerized in this way. It is preferably provided that the plasticizing takes place at temperatures preferably up to 140 ° C.

For an even more gentle treatment, the protein is intensively mixed or kneaded together with a plasticizer and subjected to mechanical stress. The required plasticizing temperature is significantly reduced by the plasticizer.

The milk protein is preferably casein or lactalbumin or soy protein.

The milk-derived protein can be made by precipitating milk in situ. For this purpose, according to a first procedure, the milk in mixture with rennet, other suitable enzymes or acid introduced directly as a flocculated mixture in the process or the pressed flocculated protein can be used wet. According to another possible method procedure, a separately previously obtained, possibly purified, pure or mixed protein, i. a protein fraction from milk are used, e.g. dried as a powder.

The protein fraction can also be produced by ultrafiltration or by cell cultures. In addition, the milk proteins can be modified, for example, with additional salts such as sodium and potassium in further processing steps, so that a casein is produced. The milk protein used according to the invention can be mixed with other proteins in a proportion of preferably up to 70% by weight, based on the milk protein. For this purpose, for example, other albumins, such as ovalbumin and vegetable proteins, in particular lupine protein, soy protein or wheat proteins, in particular gluten in question.

The mixture of solvent and protein is heated, usually under pressure conditions and shear, to accelerate the crosslinking process. Chemical or enzymatic agents can also be used to destructivate and crosslink the milk proteins, oxidize or derivatize, etherify, saponify and esterify. Usually, milk proteins are destructured by dissolving the milk proteins in water. The milk proteins are completely destructed if there are no clumps that affect the polymerisation.

A plasticizer can be used in the present invention to destructurise the milk proteins and allow the milk proteins to flow, i. H. to produce thermoplastic milk proteins. The same plasticizer or other plasticizer can be used to increase melt processability, or two separate plasticizers can be used. The plasticizers can also improve the flexibility of the final products, believed to be due to the lowering of the glass transition temperature of the composition by the plasticizer. The plasticizers are substantially compatible with the polymeric components of the present invention so that the plasticizers can effectively modify the properties of the composition. As used herein, the term "substantially compatible" means that the plasticizer, when heated to a temperature above the softening and / or melting temperature of the composition, is capable of forming a substantially homogeneous mixture with milk proteins.

The plasticizer is preferably water, which is used in an amount between 20 and 80% based on the weight of the protein, preferably in an amount of about 40 to 50 wt .-% of the protein content.

Instead of water or in a mixture with this other plasticizers, in particular alcohols, polyols, carbohydrates in aqueous solution and in particular aqueous polysaccharide solutions can be used.

Specifically, the following plasticizers and associated proportions by weight are preferred: hydrogen bridge-forming organic compounds having no hydroxyl group, e.g. Urea and derivatives, animal proteins, e.g. Gelantine, - vegetable proteins such as e.g. Cotton, soybean, and sunflower proteins, esters of generating acids which are biodegradable, e.g. Citric acid, adipic acid, stearic acid, oleic acid, hydrocarbon-based acids, e.g. Ethylene acrylic acid, ethylene maleic acid, butadiene acrylic acid, butadienoic acid, propylene acrylic acid, propylene maleic acid, sugar, e.g. Maltose, lactose, sucrose, fructose, maltodextrin, glycerol, pentaerythritol and sugar alcohols, e.g. Malite, mannitol, sorbitol, xylitol, polyols, e.g. Hexanetriol, glycols and the like, also mixtures and polymers, - sugar anhydrides, e.g. Sorbitan, esters, e.g. Glycerol acetate, (mono, - di, triacetate) dimethyl and diethyl succinate and related esters, glycerol propionates, (mono, di, tripropionate) butanoates, stearates, phthalate esters. These are non-limiting examples of hydroxylic plasticizer. Important influencing factors are the affinity for the proteins, the amount of protein and the molecular weight. Glycerine and sugar alcohols are among the most important plasticizers. Parts by weight of plasticizers are e.g. 5% - 55%, but may also be in the range of 2% - 75%. Any of alcohols, polyols, esters and polyesters may be used in proportions by weight, preferably up to 30% in the polymer blend.

Of particular importance for the polymer blend are the Theological properties, so that a good processing is possible. Strain-strain solidification is necessary to form a stable polymer structure. The melting temperature is usually in a temperature range of 30 ° C to 190 ° C. Additional temperatures should be lowered with diluents and plasticizers.

The biodegradability of the polymers, i. their decomposition by living things and their enzymes is an important property of the polymeric milk protein nanoparticles.

Biodegradable thermoplastic polymers suitable for use in the present invention include, for example, lactic acid polymers, lactide polymers, glycolide polymers, including their homo- and copolymers, and mixtures thereof; aliphatic polyesters of dibasic diols / acids; aliphatic Polyesteramides, aromatic polyesters, also of modified polyethylene terephthalates and polybutylene terephthalates; polycaprolactones; aliphatic / aromatic copolyesters; Poly (3-hydroxyalkanoates), including those copolymers and / or other -valerates, - hexanoates and alkanoates, polyesters and dialkanoyl polymers, polyamides and copolymers of polyethylene / vinyl alcohol.

As the biodegradable thermoplastic polymer for this invention, polyvinyl alcohol and copolymers, aliphatic amide and ester copolymers composed of monomers, e.g. Dialcohols (1, 4-butanediol, 1, 3-propanediol, 1, 6-hexanediol, etc.) or ethylene and diethylene glycol, aliphatic polyester amides, (aliphatic esters are formed with aliphatic amides) or by other reactions, such as. Lactic acid with diamines and dicarboxylic acid, diols with carboxylic acids, caprolactone and caprolactam, or ester prepolymers with diisocyanates, dicarboxylic acids, especially succinic, oxalic and adipic acid and their esters, hydroxycarboxylic acids, lactones, amino alcohols (eg, ethanolamine, propanolamine), cyciischen Lactamen.-aminocarboxylic acids (eg Aminocaproic acid), dicarboxylic acids and diamines (eg salt mixtures of dicarboxylic acids) and mixtures thereof. Polyester such as e.g. Oligoesters can also be used.

Polybutylene succinate / adipate copolymer; polyalkylene; Polypentamethylsuccinate; Polyhexamethylsuccinate; Polyheptamethylsuccinate; Polyoctamethylsuccinate; Polyalkylene oxalates such as polyethylene oxalate and polybutylene oxalate polyalkylene succinate copolymers such as polyethylene succinate-adipate copolymer and; Polyalkylene oxalate copolymers such as polybutylene oxalate / succinate copolymer and polybutylene oxalate / adipate copolymer; Polybutylene oxalate / succinate / adipate terpolymers; and mixtures thereof are non-limiting examples of aliphatic polyesters of dibasic acids / diols, e.g. from polymerizations of acids and alcohols or ring-opening reactions and are suitable for the production of a polymer.

Another possibility for use in the production of biodegradable polymers are aliphatic / aromatic copolyesters. These are derived from dicarboxylic acids and derivatives such as malonic, succinic, glutaric, adipic, pimelic, azelaic, sebacic, fumaric, 2,2-dimethylglutaric, suberic, 1,3-cyclopentanedicarboxylic , 1,4-Cyclohexanedicarboxylic, 1,3-cyclohexanedicarboxylic, diglycol, itaconic, maleic, 2,5-norbornanedicarboxylic, 1,4-terephthalic, 1,3-terephthalic, 2,6-naphthoic -, 1, 5 Naphthoic acid, ester-forming derivatives and mixtures thereof, and diols, eg, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol , 1, 5-pentanediol, 1, 6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, thiodiethanol, 1, 3-cyclohexanedimethanol, 1, 4-cyclohexanedimethanol, 2,2,4,4-tetramethyl -1, 3-cyclobutanediol and combinations thereof, formed in a condensation reaction. Examples of such aliphatic / aromatic copolyesters include blends of poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate-co-terephthalate), poly (tetramethylene glutarate), co-terephthalate-co-diglycolate), poly (ethylene glutarate-co-terephthalate), poly (tetramethylene adipate-co-terephthalate), an 85/15 blend of poly (tetramethylene succinate-co-terephthalate), poly (tetramethylene-co-ethylene-glutarate-co terephthalate), poly (tetramethylene-co-ethylene-glutarate-co-terephthalate).

The processability of the protein mass can be modified by other materials to influence the physical and mechanical properties of the protein mass but also of the final product. Non-limiting examples include thermoplastic polymers, crystallization accelerators or inhibitors, odor masking agents, crosslinking agents, emulsifiers, salts, lubricants, surfactants, cyclodextrins, lubricants, other optical brighteners, antioxidants, processing aids, flame retardants, dyes, pigments, fillers, proteins and their alkali salts, waxes, Adhesive resins, extenders and mixtures thereof. These adjuvants are bound to the protein matrix and influence their properties.

Salts can be added to the melt. Non-limiting examples of salts include sodium chloride, potassium chloride, sodium sulfate, ammonium sulfate, and mixtures thereof. Salts can affect the solubility of the protein in water, but also the mechanical properties. Salts can serve as binders between the protein molecules.

On the other hand, lubricants can affect the stability of the polymer. These can reduce the stickiness of the polymer and reduce the coefficient of friction. Polyethylene would be a non-limiting example. The physical properties of the polymer composition may be affected by other proteins, including without limitation, plant proteins such as sunflower protein or animal such as gelatin. Water-soluble polysaccharides and water-soluble synthetic polymers, such as polyacrylic acids, can also influence the mechanical properties.

Monoglycerides and diglycerides and phosphatides, as well as other animal and vegetable fats can influence and promote the flow properties of the biopolymer.

Inorganic fillers are also among the possible additives and can be used as processing agents. Possible examples without limitation are oxides, silicates, carbonates, lime, clay, limestone and kieselguhr and inorganic salts. Stearate-based salts and rosin can be used to modify the protein mixture.

Amino acids, the components of the proteins and peptides may be added to the polymer composition to enhance particular sheet structures or mechanical properties. Without limitation, glutamic acid, histidine, trytophan, etc. are mentioned as examples.

Other additives include enzymes, surfactants, acids, serpins, as well as phenolic plant molecules, which can contribute as crosslinkers and to improve the mechanical properties, as well as resistance to water and protease resistance.

Other additives may be desirable, depending on the particular end use of the intended product. For example, wet strength is a necessary feature in most products. Therefore, it is necessary to add wet strength resins as a crosslinking agent.

Other natural polymers can also be added as additives. Possible examples of natural polymers, without limiting the choice, would be albumins, soy protein, zein protein, chitosan, and cellulose.-polylactide "and" PLA "which can be used in an amount of 0.1% -80%. In addition to natural polymers, it is also possible to use other synthetic polymers, such as, inter alia, polyvinyl alcohol, as well as polyesters, or ethers, such as polyethylene glycol, aldehydes, such as glutaraldehyde and acrylic acids.

These include non-degradable polymers, which are used depending on the end use of the plastic. These include thermoplastics that can be used for co-polymerization, such as - without limitation: polypropylene, polyethylene, polyamides, polyesters and copolymers thereof. Other high molecular weight polymers are also possible.

Carbohydrates and polysaccharides, as well as amyloses, oligosaccharides and chenodeoxycholic acids can be used as further auxiliaries and additives.

Salts, carboxylic acids, dicarboxylic acids and carbonates, as well as their anhydrides, salts and esters can also be used as additional crosslinkers. Hydroxyde, butyl ester, as well as aliphatic hydrocarbons are other ways to cross-link molecules and form macromolecules.

The addition of other substances is not excluded. In particular, additives and auxiliaries, such as lipophilic, hydrophobic, hydrophilic, hydroscopic additives, gloss modifiers and crosslinkers may be provided. The additives and auxiliaries should overall not exceed a proportion by weight of at most about 30% by weight, based on the protein. As lipophilic additives, vegetable oils, alcohols, fats and can be chosen, which readily hydrophobicize the polymer composition during plasticizing. Furthermore, waxes and greases can be used which add strength to the polymer composition. As waxes are preferred carnauba wax, beeswax, candelilla wax and other naturally derived waxes.

After formation of the nanoparticles, the nanoparticles can be further treated or the bound substance can be treated. A hydrophilic or hydrophobic surface treatment can be added to adjust the surface energy and chemical nature of the fabric. For example, hydrophobic nanoparticles or the polymer can be treated with wetting agents to facilitate the absorption of aqueous liquids. A bound substance may also be treated with a topical solution containing surfactants, pigments, lubricants, salt, Contains enzymes or other materials to further adjust the surface properties of the MP nanoparticles or the polymer composition.

In order for the milk protein nanoparticles or their polymer composition to meet the increased requirements for improved properties for a specific purpose, they are preferably prepared in a bottom up or top down process with the required viscosity, in addition to the previously known and described production processes. This serves to increase productivity. The polymer composition is prepared by the continuous or batch processes known from the literature and the person skilled in the art, preferably by mixing or extruding a masterbatch with the addition of additives or by mixing the polymer mass by metering in the raw materials and additives during mixing or extrusion.

The process, which uses water as a solvent and plasticizer, prevents any labor law, toxicological and licensing difficulties.

Due to the plasticization, the polymer composition corresponds to a polymer in which the materials are converted by heating in a plastic state and thus deformed. The temperature exceeds the glass transition temperature of the protein, so that it passes from the amorphous to the rubbery plastic state.

After the exit of the polymer mass, e.g. from the extruder, this can be further processed directly, preferably to nanoparticles in the top-down process.

Alternatively, the polymer composition may be further processed into nanoparticles immediately after exiting the die, or in at least one later processing step.

In a further development of the invention, the polymer composition can also pass through a bath prior to curing, this procedure is not particularly preferred and usually not required. Alternatively, the polymer composition may be subjected to a spray treatment after exiting the nozzle. Here, for example, smoothing agents, waxes, lipophilic or crosslinking agents on the surface of the polymer composition be applied. In the case of crosslinkers, the following are preferred, that is, generally different salt solutions, preferably calcium chloride solution, dialdehyde starch solution, or aqueous lactic acid. Alternatively or additionally, the nanoparticles or the polymer can be a gas treatment or an ice treatment or a drying and blowing treatment or an ion treatment or a UV treatment or an enzyme treatment, as well as a renaturation by salts or esterification, etherification, saponification or a further crosslinking, and a Needling and hydroentanglement and the Kaladrieren etc. be subjected.

The resulting nanoparticles and their products can be used for any purpose. They can therefore be used for all types of medical biomaterials, for the cosmetics industry, as skin care products, e.g. also be used with UV protection, masking materials, food industry, industrial substances, medical technology, etc., polymers MP nanoparticles can be useful in the fields of textiles and paper making used.

The multi-constituent nanoparticles of the present invention may be in many different configurations. Ingredient as used herein by definition means the chemical species or material. Nanoparticles may have a monocomponent or multicomponent configuration. Component as used herein is defined as a separate part of the nanoparticle that is in spatial relationship with another part of the nanoparticle. The resulting nanoparticles can in turn be applied to a matrix.

The advantages achieved by the invention include the fact that in the production of nanoparticles according to the invention the reduction of harmful substances and environmentally harmful substances during the process and on the nanoparticles itself is made possible. In addition, the nanoparticles are biodegradable.

In addition, significant resources of energy, water, time and manpower can be saved, which increases environmental protection and improves profitability. The particularly advantageous properties of the milk protein nanoparticles are attributed to firming structural changes (textural structure) during the plasticization. The nano-sized particles, preferably having a diameter of 80-500 nanometers, are preferably made with a top-down or bottom-up method to allow for the highest possible productivity. All manufacturing methods for nanoparticles described in the art and in the literature are possible without exception. Essential to the invention is the preparation of a homogeneously plasticized polymer, preferably a biogenic biopolymer, which is preferably biodegradable. Unfortunately, no nanoparticles have been developed on this basis to date which are water-resistant and sufficiently protease-acid and alkali-resistant. The use of petroleum-based raw materials and / or organic solvents, especially in the case of nanoparticles with food contact or even as medical-technical products, as hygiene or baby articles, to name only a few examples, should preferably be reduced or even ruled out.

The production of nanoparticles, which are preferably made from renewable raw materials, with a proportion of milk proteins and with properties such as water resistance, sufficient mechanical properties, such as tensile strength, tensile strength, elastic, antibacterial and biodegradable, and the possibility exists by changing the raw material additions meet the requirements of the intended use to influence the properties of the protein nanoparticles.

Examples

In the following the invention will be described in more detail with reference to an embodiment. The embodiment is for illustrative purposes only and is not intended to limit the invention. The person skilled in the art can find further possible embodiments by varying the parameters on the basis of this exemplary embodiment and with the aid of his specialist knowledge.

Example 1: Preparation of a milk protein-polymer mass. The extrusion takes place with a twin-screw extruder type 30 E of the company. Collin with a diameter of 30 mm. The preparation of the nanoparticles is carried out by the extruded polymer mass is then extruded by high-energy ball mills pulverized into nanoparticles. Heating takes place via 4 cylinder heating zones with the following temperature sequence 65 ° C, 74 ° C, 75 ° C, 60 ° C:

The casein powder is added via a vibrating trough. A hose pump is used to add water. By further metering devices, the additives are added. The polymer composition is applied via a top down method e.g. processed a laser ablation process into nanoparticles. For example, the nanoparticles may have a diameter of 80 nm.

The course of the alternative extrusion process, in which the polymer composition is processed into nanoparticles, is additionally illustrated by FIG.

About a metering device 1, the raw materials are added to the extruder and mixed the polymer composition. After passing through a nozzle 3 and a device 4 for infrared irradiation and blowing the polymer mass passes into a grinder 5, where it is optionally ground with different degrees of grinding.

LIST OF REFERENCE NUMBERS

1 metering device

2 extruders

3 nozzle

4 Infrared irradiation / blowing device

5 grinder

Claims

claims:

1. A process for the preparation of milk protein nanoparticles formed from at least one homogeneous polymer based on milk-derived proteins, which are plasticized with the addition of heat and a plasticizer.

2. The method according to claim 1, characterized in that the preparation by means of a top down or botton up process takes place.

3. The method according to claim 1 or 2, characterized in that the nanoparticles are produced from biogenic and renewable raw materials and are biodegradable.

4. The method according to any one of the preceding claims, characterized in that the preparation of the nanoparticles takes place continuously or discontinuously.

5. The method according to any one of the preceding claims, characterized in that the polymer mixture is plasticized before production of the nanoparticles by a continuous or discontinuous process under mechanical stress.

6. The method according to any one of the preceding claims, characterized in that the milk protein nanoparticles are water resistant, harmless to health and biodegradable.

7. The method according to any one of the preceding claims, characterized in that at least one milk-derived protein is plasticized together with a plasticizer under mechanical stress.

8. The method according to any one of the preceding claims, characterized in that the plasticizing takes place at temperatures up to 140 ° C.

9. The method according to any one of the preceding claims, characterized in that the milk-derived protein either by precipitation from milk in situ is prepared or used in the form of a previously separately recovered and optionally processed protein or a protein fraction.

10. The method according to any one of the preceding claims, characterized in that the proteins obtained from milk are obtained from bacteria.

11. The method according to any one of the preceding claims, characterized in that the proteins obtained from milk are obtained by gas treatment or filtration.

12. The method according to any one of the preceding claims, characterized in that the proteins obtained from milk, in particular casein, lactalbumin or soy protein, are obtained from goat's milk, sheep's milk, cow's milk or soy milk.

13. The method according to any one of the preceding claims, characterized in that the plasticizer is selected from the group: water, aqueous carbohydrate solution and in particular aqueous polysaccharides, oligosaccharides, proteins, alcohol, polyhydric alcohol, fats, acids, amino acid, peptides, salts, cations, Enzymes or mixtures of these agents, as well as their oxidation.

14. The method according to any one of the preceding claims, characterized in that the additive to be plasticized further additives and auxiliaries are added, optionally by admixing before or during the plasticizing.

15. Method according to one of the preceding claims, characterized in that the nanoparticles or the polymer are dried and after-treated by passing through a bath or a spray treatment or a gas treatment or an ice treatment or a drying and blowing treatment or an ion treatment or a UV treatment. Treatment, needling and hydroentanglement treatment, infrared treatment or an enzyme treatment, as well as a renaturation by salts or alcohols, esters and ether esterification, etherification or saponification or a further crosslinking.

16. The method according to any one of the preceding claims, characterized in that carboxylic acids, dicarboxylic acids and carbonates, and their salts, esters and fatty acids are used for the polymer mixture.

17. The method according to any one of the preceding claims, characterized in that the polymer mass or nanoparticles during or after the process by chemical or enzymatic means destructured, oxidized or derivatized, etherified, esterified or saponified.

18. The method according to any one of the preceding claims, characterized in that the polymer mixture amino acids are added.

19. The method according to any one of the preceding claims, characterized in that the polymer composition with protease inhibitors, preferably enzymes, surfactants, acids, serpins, phenolic molecules from plants and / or polysaccharides is added or post-treated.

20. The method according to any one of the preceding claims, characterized in that aliphatic esters and aliphatic amide copolymers, preferably biodegradable, are added to the polymer mixture.