WO2014135795A1

WO2014135795A1 - Method for the reactive extrusion of compositions containing at least one amylaceous material in a mixture with another component, resulting products and uses thereof

Info

Publication number: WO2014135795A1
Application number: PCT/FR2014/050494
Authority: WO
Inventors: Julien Parcq; René SAINT-LOUP; Vincent Wiatz
Original assignee: Roquette Freres
Priority date: 2013-03-08
Filing date: 2014-03-05
Publication date: 2014-09-12
Also published as: FR3002938A1; FR3002938B1

Abstract

The present invention relates to a method for the reactive extrusion of compositions containing at least one amylaceous material and another component selected from a comprehensive list, said extrusion taking place in the presence of at least one cross-linking agent and at least one solvent and/or plasticizer. Advantageously, the method according to the invention makes it possible to control the competition between the destructuring and the cross-linking of the starch. Said method therefore makes it possible to obtain compositions made of cross-linked starches with residual crystalline phase levels that can be adjusted in order to ideally meet the specific needs of the different end applications.

Description

The present invention relates to a process for the reactive extrusion of a composition containing at least one starchy material and another method for the reactive extrusion of a composition containing at least one amylaceous material and another method for the reactive extrusion of a composition containing at least one starchy material and another component selected from an exhaustive list, said extrusion taking place in the presence of a crosslinking agent and a solvent and / or plasticizer. Advantageously, the method according to the invention makes it possible to control the competition between the destructuring and the crosslinking of the starch mixed with one or more other components. This method therefore makes it possible to obtain compositions based on crosslinked starches with adaptable residual crystalline phase levels in order to ideally meet the specific needs of the different end applications. Reactive extrusion is a well-known technique for forming starchy materials in the form of nano-sized particles, which can then be dispersed in water or in a hydroalcoholic solvent. This technology is based on a first step of extruding the starchy material in the presence of a crosslinking agent, followed by possible granulation and grinding steps. By adding water or a hydroalcoholic solvent, it is finally possible to achieve dispersions with a dry matter content of at least 20% by dry weight of starchy material, stable over time, and having a size of particles between 100 and 500 nm as determined by laser particle size.

This technology has been reported in documents EP 1 159 301 and then incorporated and refined in documents EP 1 303 667, EP 1 303 670 and EP 2 251 484, these 3 documents aimed at products obtained from applications in the manufacture of paper. . More specifically, the latter documents are directed towards the manufacture of compositions intended to cover the paper sheet to confer in particular improved optical properties, said compositions being known by those skilled in the art under the term "coating colors".

As shown by the last 3 cited documents, the implementation of particles made by reactive extrusion in paper coating coatings, allows to substitute in part the synthetic binders commonly used in such applications and this, while maintaining an equivalent level of properties: both in the actual coating color, in terms of high and low shear rate viscosity (Brookfield viscosity and Haake), but also at the paper sheet in terms of water retention and printability.

In addition, all the aforementioned documents focuses on starch as the sole material undergoing the reactive extrusion operation. However, from the point of view of the final application where the starch is mostly intended to be mixed with other components, it is interesting to consider the reactive extrusion of a composition containing at least one starchy material. and at least one other component. By this is meant that the starchy material is introduced into the extruder in admixture with at least one other component and / or that there is distinctly introduced in the extruder at least one starchy material and at least one another component.

The other component is here chosen from cellulose, lignin, carboxymethylcellulose (CMC), hemicellulose, gluten, proteins and especially pea proteins, guar, xanthan, carrageenan, alginates, chitosan , cassia, tamarind, gelatin, lipids, triglycerides, unsaturated fatty acids or not, algae and micro-algae.

One of the merits of the Applicant is to have demonstrated that the reactive extrusion of at least one starchy material with at least one other component selected from the aforementioned list was feasible from an industrial point of view.

Also, a first object of the present invention consists in a process for producing particles consisting of at least one starchy material, said process comprising: a) at least one step of extruding at least one starchy material and from at least one other component, in the presence of at least one crosslinking agent and at least one solvent and / or plasticizer,

b) optionally a granulation step,

c) optionally a grinding stage, d) optionally a dispersing step in a solvent, the other component being chosen from cellulose, lignin, carboxymethylcellulose (CMC), hemicellulose, gluten, proteins and in particular pea proteins, guar , xanthan, carrageenan, alginates, chitosan, cassia, tamarind, gelatin, lipids, triglycerides, unsaturated fatty acids or not, algae and microalgae.

In addition, the Applicant has managed, by identifying and regulating certain parameters of his process, to obtain particularly advantageous products in their application. This is in particular achieved through the fine control of the phenomenon of destructuring of the starchy material and its content in the crystalline phase. According to a first variant, such control is obtained when the solvent and / or plasticizer is present in a proportion of at least 35%, preferably at least 40%, very preferably at least 45%, and so the more preferably at least 50% by weight in the extrudate at the time the crosslinking agent is introduced into the extruder. It is specified that the extrudate designates all of the material present in the extruder.

In another version of the invention, the competition between the aforementioned mechanisms is managed by the introduction of an alkaline catalyst, which participates in the destructuration. In this case, the extrusion step is performed by introducing into the extruder an alkaline catalyst. It will then be preferred to introduce the crosslinking agent before said alkaline catalyst into the reaction medium: this effectively disperses the crosslinking agent in the material. The alkaline catalyst is then chosen from alkali and alkaline earth oxides and hydroxides. In general, the extrusion step a) is carried out in an extruder: this device is the site of important shearing forces that apply to the starch. In addition, this step is carried out at a temperature of at least 60 ° C, preferably at least 70 ° C, very preferably at least 80 ° C, but in all cases at a temperature below the degradation temperature of the material starchy; choosing this temperature is a skill normal to those skilled in the art, with regard to the physico-chemical characteristics of the materials used. The process generates a pressure of between 5 bar and 150 bar. The extrusion step a) is carried out by introducing into the extruder the starchy material, the other component, the crosslinking agent and a solvent and / or plasticizer.

The starchy material is generally introduced at the bottom of the extruder (i.e. in zone 1 as indicated in the experimental section), but may also be introduced into any zone other than the latter. This introduction can be achieved by gravimetric insertion from above the extruder or by the use of specific introduction systems known to those skilled in the art such as "side-feeder" for example. The starchy material may be introduced in admixture with another starchy material and / or in admixture with the other component. This mixture is therefore generally introduced in zone 1, but can be introduced in any zone other than the latter. As such, the mixture can be obtained by homogenization in a device of the "dry-blend" type.

The starchy material may finally be introduced in combination with another starchy material and with the other component, but not in the form of a mixture. This means that the ingredients are either introduced in the same zone (but not in a mixture) except for the last zone, or in separate zones.

In all cases, when the ingredients are introduced separately, they are introduced from conventional dosing systems well known to those skilled in the art.

The extrusion step a) is carried out by introducing into the extruder a solvent and / or plasticizer chosen from water and hydroalcoholic solvents. Preferentially it is water. This solvent is used to destructure the starch fraction and can be introduced into any zone of the extruder. The more it is added towards the end of the extruder, the more the duration and thus the rate of destructuring will be limited. It is also possible to envisage systems where the solvent is injected before the introduction of the starchy material in the extruder. In another variant of the process, the solvent, the starchy material and the other component are introduced simultaneously in the form of an aqueous dispersion of starchy material of the "slurry" type. The extrusion step a) is also carried out by introduction into the extruder of a crosslinking agent chosen from sodium trimetaphosphate, glyoxal, diepoxides and water-soluble diisocyanates, and is preferably sodium trimetaphosphate. The crosslinking agent represents from 0.1% to 10% by dry weight relative to the dry weight of starch material used. The zone of introduction of said agent and in particular its relative position with respect to the zone of introduction of the solvent (in particular the water) is a critical parameter in the optics of the control of the competition between the destructuration of the amylaceous material and the crosslinking reaction between the nucleophilic functions carried by the starchy material and at least one of the other components.

The starchy material may be chosen from "granular starches". The term "granular starch" is used herein to mean a starch which is native or physically modified, chemically or enzymatically, and which has retained, within the starch granules, a semicrystalline structure similar to that evidenced in starch grains. naturally occurring in reserve organs and tissues of higher plants, particularly in cereal grains, legume seeds, potato or cassava tubers, roots, bulbs, stems and fruits. This semi-crystalline state is essentially due to macromolecules of amylopectin, one of the two main constituents of starch. In the native state, the starch grains have a degree of crystallinity which varies from 15% to 45%, and which essentially depends on the botanical origin of the starch and the possible treatment that it has undergone. Granular starch, placed under polarized light, has a characteristic black cross, so-called Maltese cross, typical of the granular state.

According to the invention, the granular starch can come from all botanical origins, including a granular starch rich in amylose or conversely, rich in amylopectin (waxy). It may be native cereal starch such as wheat, maize, barley, amaranth, triticale, sorghum or rice, tubers such as potatoes or cassava, or legumes such as peas, mango beans and soybeans, and mixtures of such starches. According to one variant, the granular starch is an acid hydrolyzed, oxidizing or enzymatic starch, or an oxidized starch. It can be a starch commonly called fluidized starch, or a white dextrin.

According to another variant, it may also be a starch modified physico-chemically but having essentially retained the structure of the native starch starting, such as in particular esterified and / or etherified starches, in particular modified by acetylation , hydroxypropylation, cationization, crosslinking, phosphatation, or succinylation, or starches treated in aqueous medium at low temperature (in English "annealing"). Preferably, the granular starch is a native, hydrolysed, oxidized or modified starch, in particular corn, wheat, peas or potato.

Granular starch generally has a solubility level of 20% in demineralized water, less than 5% by weight. It is preferably almost insoluble in cold water.

According to a second variant, the starchy material may be a water-soluble starch, which may also come from all botanical origins, including a water-soluble starch rich in amylose or, conversely, rich in amylopectin (waxy). This water-soluble starch can be introduced as a partial or total replacement of the granular starch.

For the purposes of the invention, the term "water-soluble starch" means any starchy component having at 20 ° and under mechanical stirring for 24 hours, a fraction soluble in demineralised water at least equal to 5% by weight. This soluble fraction is preferably greater than 20% by weight, and in particular greater than 50% by weight. Of course, the water-soluble starch can be totally soluble in demineralized water (soluble fraction = 100%). Such water-soluble starches can be obtained by pregelatinization on a drum, by pregelatinization on an extruder, by spraying a suspension or a starch solution, by precipitation with a non-solvent, by hydrothermal cooking, by chemical functionalization or the like. It is in particular a pregelatinized, extruded or atomized starch, a highly converted dextrin (also called yellow dextrin), a maltodextrin, a functionalized starch or any mixture of these products.

The pregelatinized starches may be obtained by hydrothermal treatment of gelatinization of native starches or modified starches, in particular by steam cooking, jet-cooker cooking, drum cooking, cooking in kneader / extruder systems, then drying for example. in an oven, by hot air on a fluidized bed, on a rotating drum, by atomization, by extrusion or by lyophilization. Such starches generally have a solubility in demineralized water at 20 ° C. of greater than 5% by weight and more generally of between 10% and 100%, and a starch crystallinity level of less than 15% (in X-ray diffraction intensity). ), generally less than 5%, and most often less than 1%, or even zero. By way of example, mention may be made of the products manufactured and marketed by the Applicant under the brand name PREGEFLO®.

The highly converted dextrins are also part of the starchy materials that can be used in the context of the invention. They can be prepared from native or modified starches, by dextrinification in acid medium with little hydration. It may be in particular soluble white dextrins or yellow dextrins. By way of example, mention may be made of STABILYS® A 053 or TACKIDEX® C 072 products, manufactured and marketed by the Applicant. Such dextrins have, in demineralized water at 20 ^q C, a solubility comprised generally between 10% and 95% by weight and a starch crystallinity 15%, generally less than 5%.

Maltodextrins and dehydrated glucose syrups are also suitable for the present invention. They can be obtained by acid, oxidative or enzymatic hydrolysis of starches in an aqueous medium. They may have in particular an equivalent dextrose (DE) of between 0.5 and 40, preferably between 0.5 and 20 and better still between 0.5 and 12. Such maltodextrins or glucose syrups dehydrated are for example manufactured and marketed by the Applicant under the trade name GLUCIDEX® and have a solubility in demineralized water at 20 ° C generally greater than 90% or even close to 100%, and a crystallinity in starch generally less than 5% and usually almost zero.

The functionalized starches can be obtained from a native or modified starch. The functionalization can for example be carried out by esterification or etherification at a sufficiently high level to confer a solubility in water. Such functionalized starches have a soluble fraction, as defined above, greater than 5%, preferably greater than 10%, more preferably greater than 50%.

The functionalization can be obtained in particular by acetylation in aqueous phase with acetic anhydride, by reaction with mixed anhydrides, by hydroxypropylation in the glue phase, by cationization in dry phase or glue phase, by anionization in dry phase or glue phase. by phosphatation or succinylation. The water-soluble high functionalized starches obtained may have a degree of substitution of between 0.01 and 3, and more preferably between 0.05 and 1. Preferably, the reagents for modifying or functionalizing the starch are of renewable origin.

According to another advantageous variant, the water-soluble starch is a water-soluble starch of corn, wheat or peas, or a water-soluble derivative thereof. In addition, it advantageously has a low water content, generally less than 10%, preferably less than 5%, in particular less than 2.5% by weight, and ideally less than 0.5%, or even less than 0%, 2% by weight.

According to a third variant, the amylaceous component selected for the preparation of the composition is an organomodified starch, preferably organosoluble, which may also come from all botanical origins, including an organomodified starch, preferably organosoluble, rich in amylose or, conversely, rich in amylopectin (waxy). This organosoluble starch may be introduced as partial or total replacement of the granular starch or of the water-soluble starch. For the purposes of the invention, the term "organomodified starch" means any starchy component other than a granular starch or a water-soluble starch according to the definitions given above. Preferably, this organomodified starch is almost amorphous, that is to say having a starch crystallinity level of less than 5%, generally less than 1% and especially zero. It is also preferably "organosoluble", that is to say having at 20 ° C, a fraction soluble in a solvent selected from ethanol, ethyl acetate, propyl acetate, butyl acetate , diethyl carbonate, propylene carbonate, dimethyl glutarate, triethyl citrate, dibasic esters, dimethyl sulfoxide (DMSO), dimethyl isosorbide, glycerol triacetate, isosorbide diacetate, isosorbide dioleate and methyl esters of vegetable oils, at least equal to 5% by weight. This soluble fraction is preferably greater than 20% by weight and in particular greater than 50% by weight. Of course, the organosoluble starch may be totally soluble in one or more of the solvents indicated above (soluble fraction = 100%).

The organomodified starch may be used according to the invention in solid form, including having a low water content, ie less than 10% by weight. It may especially be less than 5%, in particular less than 2.5% by weight and ideally less than 0.5%, or even less than 0.2% by weight.

The organomodified starch that can be used in the composition according to the invention can be prepared by functionalization of the native or modified starches such as those presented above. This functionalization can for example be carried out by esterification or etherification at a sufficiently high level to make it essentially amorphous and to confer on it an insolubility in water and preferably a solubility in one of the organic solvents above. Such functionalized starches have a soluble fraction, as defined above, greater than 5%, preferably greater than 10%, more preferably greater than 50%.

The functionalization can be obtained in particular by acetylation in the solvent phase with acetic anhydride, grafting, for example in the solvent phase or by reactive extrusion of acid anhydrides, mixed anhydrides, fatty acid chlorides, oligomers of caprolactones or lactides, hydroxypropylation and crosslinking in glue phase, cationization and crosslinking in the dry phase or in the glue phase, anionization by phosphatation or succinylation, and crosslinking in the dry phase or in the glue phase, silylation, butadiene telomerization. These organomodified, preferably organosoluble, highly functionalized starches can be, in particular, starch acetates, dextrins, maltodextrins of dehydrated glucose syrups or fatty esters of these starchy materials (starches, dextrins, maltodextrins of dehydrated glucose syrups). with fatty chains of 4 to 22 carbons, all of these products preferably having a degree of substitution (DS) of between 0.5 and 3.0, preferably of between 0.8 and 2.8, and in particular of between 1, 0 and 2.7.

It may be, for example, hexanoates, octanoates, decanoates, laurates, palmitates, oleates and stearates of starch, dextrins, maltodextrins, dehydrated glucose syrups, in particular having a DS between 0.8 and 2.8. According to another advantageous variant, the organomodified starch is an organomodified starch of corn, wheat or peas or an organomodified derivative thereof. In all cases, the dry matter content of starchy material in the extruder is at least 40%, preferably at least 50%, very preferably at least 60% by dry weight of the extruder contents.

Optional step b) of the process according to the invention comprises granulating the extrudate at the extruder outlet. This operation is performed by all available means for granulating.

The granulation is then followed by an optional step c) grinding, in particular a step of mechanical grinding on a solid, mechanical grinding after dispersion in a water or aqueous-alcoholic solvent, followed by a step of extraction of the solid (by example by lyophilization), or cryogenic grinding, the objective of this treatment being to make a decrease in the particle sizes of the granules from the previous step. Finally, and optionally, the granules from step b) or the ground particles from step c) can be dispersed in water or a hydroalcoholic solvent, preferably in water. Other objects of the present invention are constituted by:

the extrudate obtained by the process according to the invention in which only step a) has been used,

the granules obtained by the process according to the invention in which only steps a) and b) have been implemented,

the crushed particles obtained by the process according to the invention in which only steps a) and c) have been implemented, and optionally step b) intermediate,

the dispersions obtained by the process according to the invention in which only steps a) and d) have been implemented, and possibly intermediate steps b) and c).

Another subject of the present invention relates to tablets, pellets, or products obtained by shaping the ground particles described above, said particles optionally being additive of an active ingredient before forming.

A final subject of the present invention relates to the use of the ground particles and dispersions mentioned above, as well as tablets, tablets and products indicated above, in the manufacture of wet films, in the manufacture of paper and in the manufacture of coating sauces, in the field of drugs as a carrier of active principle, in cosmetology, in agriculture and horticulture, in human and animal nutrition, in the manufacture of mixtures with synthetic polymers.

The following examples make it possible to better understand the present invention without limiting its scope. EXAMPLES

Concretely, different screw profiles can be used to control the specific thermomechanical energy transmitted to the material and thus control the competition between destructure of the starch and crosslinking reactions.

A screw profile is defined through the different zones that constitute said screw. Each zone (Z) consists of a particular element (P) ensuring in particular the transport or the shearing at a certain angle of the material passing through it. Each zone is also associated with a particular temperature (T).

For elements, we use the following notations:

T: conveying elements with different screw threads

M: highly dispersive mixing elements with a very low shear component

C: includes all elements with a high shear component, ie all shear elements at 30 45 60 and 90 ⁰ in direct steps, and also 45 45 60 ⁰ in reverse order and transport elements or reverse mixing. Example of a mixture of pea starch and waxy corn starch crosslinked with sodium trimetaphosphate for a relarqaqe type application, controlled diffusion of active ingredients or controlled diquisibility

A mixture of native pea starch with a water content of 13% (starch) and waxy corn starch with a moisture content of 12% (compound B) is introduced into an extruder using a volumetric power supply. The mixture can be introduced into zone 1 of the extruder which has 15 zones. The screw speed is set at 500 rpm.

The water and the crosslinking agent (in this case sodium trimetaphosphate) are then added at zone 2 by means of a piston pump. At zone 9, a solution of sodium hydroxide is introduced.

Such a process is called "method 1", making it possible to obtain homogeneous mixtures (see FIG. 1/3). This mixture can also be carried out by dissociated introduction without crosslinking of compound B, allowing incorporation of compound B into the mixture: "process 2" (see FIG. 2/3).

This mixture can finally be produced with cascade crosslinks: "process 3" (see FIG. 3/3).

The Applicant recommends more particularly to implement the following mixtures:

Manufacture of a product for application "release, controlled diffusion of active ingredients and controlled digestibility": pea starch and waxy corn starch, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1, 2 and 3

Manufacture of a product for application "release, controlled diffusion of active ingredients and controlled digestibility": pea starch and potato starch, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1, 2 and 3

Manufacture of a product for application "release, controlled diffusion of active principles": pea starch and β-cyclodextrin, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to the method 3

Manufacture of a product for application "release, controlled diffusion of active principles": pea starch and microcrystalline cellulose, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to the method 3

Manufacture of a product for application "release, controlled diffusion of active principles": pea starch and cellulose, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to the method 3

Manufacture of a product for application "release, controlled diffusion of active ingredients": pea starch and gluten, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to the method 3

Manufacture of a product for application "release, controlled diffusion of active ingredients": pea starch and pea protein, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to the method 3

Manufacture of a product for application "release, controlled diffusion of active principles": pea starch and pectin, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to the method 3

Manufacture of a product for application "release, controlled diffusion of active ingredients": potato starch and waxy corn starch, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for application "release, controlled diffusion of active ingredients": potato starch and pea starch, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1, 2 and 3

Manufacture of a product for application "coatings": waxy corn starch and potato starch, with glyoxal as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for application "release, controlled diffusion of active ingredients": waxy corn starch and pea starch, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1, 2 and 3

Manufacture of a product for "Coatings, resins and paints" application: waxy corn starch and fluidized pea and hydroxypropyl starch with water-soluble diisocyanate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for "paper coating" application: waxy corn starch and cellulose nano whiskers, with diepoxides as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for "binder or compound application with properties of plastic injectable, biobased and biodegradable" type: waxy corn starch and cellulose microfibrillate, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2 Manufacture of a product for application "release, controlled diffusion of active ingredients": waxy corn starch and gluten, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for application "release, controlled diffusion of active ingredients": waxy corn starch and pea protein, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for application "release, controlled diffusion of active ingredients": waxy corn starch and guar gum, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for application "release, controlled diffusion of active ingredients": waxy maize starch and xanthate, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Manufacture of a product for application "release, controlled diffusion of active ingredients": waxy corn starch and carrageenan, with sodium trimetaphosphate as crosslinking agent; the compounds that can be used according to processes 1 and 2

Claims

1 - Process for producing particles consisting of at least one starchy material, said process comprising: a) at least one step of extruding at least one starchy material and at least one other component, in the presence of at least one at least one crosslinking agent and at least one solvent and / or plasticizer,

b) optionally a granulation step,

c) optionally a grinding stage,

d) optionally a dispersing step in a solvent, the other component being chosen from cellulose, lignin, carboxymethylcellulose (CMC), hemicellulose, gluten, proteins and in particular pea proteins, guar , xanthan, carrageenan, alginates, chitosan, cassia, tamarind, gelatin, lipids, triglycerides, unsaturated fatty acids or not, algae and microalgae. 2 - Process according to claim 1, characterized in that the solvent and / or plasticizer is present in a proportion of at least 35%, preferably at least 40%, very preferably at least 45%, and so the more preferably at least 50% by weight in the extrudate at the time the crosslinking agent is introduced into the extruder.

3 - Process according to any one of claims 1 to 2, characterized in that step a) is carried out at a temperature of at least 60 ° C, preferably at least 70 ° C, very preferably at least 80 ° C. 4 - Process according to any one of claims 1 to 3, characterized in that step a) is carried out by introduction into the extruder of a solvent and / or plasticizer selected from water and hydroalcoholic solvents, preferentially the water. 5 - Process according to any one of claims 1 to 4, characterized in that step a) is carried out by introduction into the extruder of a crosslinking agent selected from sodium trimetaphosphate, glyoxal, diepoxides, water-soluble diisocyanates, and preferentially sodium trimetaphosphate.

6 - Process according to any one of claims 1 to 5, characterized in that step a) is carried out by introduction into the extruder of an alkaline catalyst, said alkaline catalyst then being selected from alkaline oxides and hydroxides and alkaline earth, and being preferentially introduced into the extruder after the crosslinking agent.

7 - extrudate obtained by the method according to any one of claims 1 to 6 wherein it has implemented that step a). 8 - Granules obtained by the method according to any one of claims 1 to 6 wherein it has implemented that steps a) and b).

9 - Crushed particles obtained by the method according to any one of claims 1 to 6 wherein it has implemented that steps a) and c), and optionally step b) intermediate.

10 - Dispersions obtained by the method according to any one of claims 1 to 6 wherein it has implemented that steps a) and d), and optionally intermediate steps b) and c).

1 1 - Tablets, pellets, or products obtained by shaping the ground particles according to claim 9, said particles possibly being additive of an active ingredient before shaping. 12 - Use of the crushed particles according to claim 9, dispersions according to claim 10, tablets, pellets and products according to claim 1 1, in the manufacture of wet films, in the manufacture of paper and in the manufacture of coating coatings , in the field of medicines as a vector of active principle, in cosmetology, in agriculture and horticulture, in human and animal nutrition, in the manufacture of mixtures with synthetic polymers.