Use as an emulsifying base in a cosmetic or pharmaceutical formulation, in a composition containing stearoyl glutamate

Abstract

Use as an emulsifying base in a cosmetic or pharmaceutical formulation, of a composition comprising a mixture of alkali metal stearoyl glutamate and stearoyl glutamic acid, characterized in that the composition has a pH measured at 25°C at 5% in an aqueous solution between 7.8 and 9.2. Process for manufacturing the emulsifying base and cosmetic or pharmaceutical composition containing it.

Description

Title of the invention: Use as an emulsifying base in a cosmetic or pharmaceutical formulation, of a composition comprising stearoyl glutamate Technical field

[0001] The invention relates to the use as an emulsifying base in a cosmetic or pharmaceutical formulation, of a composition comprising, as surfactant, stearoyl glutamate, that is to say a mixture of alkali metal stearoyl glutamate and stearoyl glutamic acid, a fatty phase and an aqueous phase. The invention also relates to a cosmetic or pharmaceutical formulation incorporating such an emulsifying base as well as to a method for manufacturing said emulsifying base. Prior art

[0002] A number of emulsifying bases have been developed for the cosmetic or pharmaceutical market. Their objective is to enter cosmetic or pharmaceutical formulations in the form of an emulsion.

[0003] Applicant's document WO2007 / 042723 describes an emulsifying base comprising a wax derivative obtained by reaction of jojoba wax, rice wax, candelilla wax and polyglycerol. The base further comprises cetostearyl alcohol, glycerol stearate and, as a surfactant, sodium stearoyl lactylate.

[0004] Even if this base gives satisfactory emulsifying properties to the compositions which contain it, the stability of the surfactant during storage before preparation of the base, and in particular the risk of hydrolysis of the lactylate group, remains problematic. Furthermore, the presence of poor quality of the lactylate derivative can give the emulsifier an undesirable odor.

[0005] Document US2008 / 249192A1 describes an emulsifying base comprising an anhydrous wax containing (a) a compound selected from pentaerythritol, dipentaerythritol, and tripentaerythritol esters and (b) at least one ester of glycerol and C 12 24 fatty acids, the mass ratio between (a) and (b) being from 1:3 to 3:1. The base further contains, as a surfactant, monosodium or disodium stearoyl glutamate.

[0006] The commercial product sold under the name of commercially available sodium stearoyl glutamate (SSG) is an ionic surfactant composed of an acid form (stearoyl glutamic acid) and an ionic basic form (sodium stearoyl glutamate), the ratio of which varies depending on the origin or supplier of the raw material.

[0007] Substituting sodium stearoyl lactylate with stearoyl glutamate solves the problems of odor and hydrolysis but has certain disadvantages.

[0008] The first of these is that sodium stearoyl glutamate is insoluble in fatty phases, whereas stearoyl glutamic acid is, which requires constant stirring to prevent the particles from settling and is essential to obtain a homogeneous mixture.

[0009] This problem of homogeneity also makes it impossible to obtain divided solid forms, for example pellets or flakes, which are themselves of homogeneous composition. In practice, to manufacture pellets, it is necessary to use a pelletizer which must be fed with a homogeneous liquid free of suspended particles. In addition, the presence of these particles can contribute to blocking the orifices and make pelletizing impossible. In addition, the passage from the reactor to the pelletizer is done via unstirred transfer zones, in which the SSG tends to sediment.

[0010] The Applicant further noted that the emulsifying performance of stearoyl glutamate varied from one raw material to another, making it difficult to reproduce the emulsifying power of the bases incorporating them from one batch to another or from one supplier to another.

[0011] More specifically, the Applicant found that stearoyl glutamate, depending on its origin, did not have the same surfactant performances, giving the formulations different viscosities and stabilities.

[0012] Document FR3080766A1 describes a hair cosmetic composition comprising a wax derivative obtained by the simultaneous transesterification reaction of a mixture comprising jojoba wax and sunflower wax, in the presence of polyglycerol-3. Examples 12 and 13 respectively describe a moisturizing night cream for the hair and a strengthening hair mask comprising, in addition to the wax derivative, stearoyl glutamate. The combination of wax and stearoyl glutamate is not described as an emulsifying base.

[0013] Consequently, the problem which the invention proposes to solve is that of developing an emulsifying base based on stearoyl glutamate which does not have the above drawbacks.

[0014] In other words, the problem that the invention sets out to solve is that of developing an emulsifying base based on stearoyl glutamate, a fatty phase and an aqueous phase: - whose liquid form, like the solid form, is homogeneous, - which has equivalent emulsifying performance, regardless of the origin of the stearoyl glutamate. Statement of the invention

[0015] The Applicant has found that the combination of a succession of stirring and resting steps and a precise proportion of aqueous phase allowing the adjustment of the neutralization rate of the stearoyl glutamate, makes it possible to achieve, after mixing all the constituents, a perfect dissolution of the sodium stearoyl glutamate in the fatty phase.

[0016] The Applicant has also found that constant emulsifying performance is obtained, regardless of the origin of the stearoyl glutamate, from the moment when the pH of the stearoyl glutamate in solution at 5% by mass in water is between 7.8 and 9.2.

[0017] The Applicant thus hypothesizes that the ratio of acid form (stearoyl glutamic acid) / basic form (sodium stearoyl glutamate) contained in stearoyl glutamate had an impact on the surfactant performance of stearoyl glutamate when it was incorporated into an emulsion.

[0018] In other words, the subject of the invention is the use as an emulsifying base in a cosmetic or pharmaceutical formulation, of a composition comprising a fatty phase, an aqueous phase, and a surfactant consisting of a mixture of alkali metal stearoyl glutamate and stearoyl glutamic acid.

[0019] The invention is characterized in that the stearoyl glutamate has a pH measured at 25°C at 5% by mass in an aqueous solution between 7.8 and 9.2.

[0020] In other words, the Applicant found that it was necessary to measure and, if necessary, adjust the acid form / basic form ratio of stearoyl glutamate so as to obtain a pH of between 7.8 and 9.2 under the above conditions in order to have a stearoyl glutamate whose emulsifying performance is robust and reproducible.

[0021] According to a first characteristic, the alkali metal of stearoyl glutamate is sodium or potassium.

[0022] In a preferred embodiment, the surfactant contains sodium stearoyl glutamate.

[0023] According to another characteristic, the surfactant represents between 5 and 12%, advantageously between 7 and 9% by mass of the emulsifying base, concentrations of surfactant at which the emulsifying base achieves the best effects in terms of viscosity and stability in particular.

[0024] To ensure satisfactory solubilization of the stearoyl glutamate, the aqueous phase represents between 1 and 5%, advantageously between 2 and 3.5% by mass of the emulsifying base. Below these values, the Applicant has found that either there is not enough aqueous phase to allow complete solubilization of the stearoyl glutamate in the fatty substance, i.e. all of the stearoyl glutamate, is certainly solubilized but an excess of aqueous phase appears and settles at the bottom of the mixer.

[0025] In a preferred embodiment, the fatty phase comprises a wax derivative obtained by the simultaneous transesterification reaction of a mixture comprising jojoba wax and sunflower wax, in the presence of polyglycerol-3.

[0026] In practice, the wax derivative represents between 20 and 40%, preferably between 24 and 35% by mass of the fatty phase.

[0027] Advantageously, the fatty phase further comprises at least one C16-C18 fatty alcohol and glycerol palmitostearate.

[0028] In practice, the at least one C16-C18 fatty alcohol and the glycerol palmitostearate represent respectively between 35 and 50% by mass of the fatty phase and between 20 and 30% by mass of the fatty phase.

[0029] Given that the emulsifying base of the invention is homogeneous in liquid form when hot, it can be easily pelletized to appear in the form of individualized solid particles and in particular in the form of flakes or pellets of a size greater than or equal to 1 millimeter.

[0030] The invention also relates to a cosmetic or pharmaceutical formulation, in particular topical, comprising the emulsifying base as described above.

[0031] In practice, the emulsifying base represents between 1 and 8%, preferably between 2 and 5% by mass of the composition.

[0032] The emulsifying base of the invention can be implemented in all the galenic forms normally used for topical application to the skin, lips or hair, in particular within a cosmetic composition in the form of an oil-in-water or water-in-oil or multiple emulsion, a silicone emulsion, a microemulsion or nanoemulsion.

[0033] The composition may be more or less fluid and have the appearance, among other things, of a white or colored cream, an ointment, a milk, a lotion, a serum. The composition may also be packaged in an aerosol and may be in the form of a mousse, spray or stick.

[0034] The composition may contain the usual adjuvants in the cosmetic and dermatological fields, such as fatty substances, emulsifiers and co-emulsifiers, hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active agents, preservatives, antioxidants, solvents, perfumes, fillers, hydrophilic and lipophilic sunscreens, coloring matters, bases and acids, pro-penetrating agents, and polymers.

[0035] The quantities of these different adjuvants are those conventionally used in the fields considered, and for example from 0.01 to 40% of the total mass of the com position. These adjuvants, depending on their nature, can be introduced into the fatty phase or into the aqueous phase.

[0036] As fatty substances which can be used in the cosmetic composition of the invention, mineral oils, oils of animal origin (lanolin), vegetable oils, synthetic oils (isopropyl myristate, octyldodecanol, isostearyl isostearate, decyl oleate, isopropyl palmitate, caprylic / capric triglycerides), silicone oils (cyclomethicone, dimethicone) can be used. Fatty alcohols, fatty acids, waxes, butters, hydrogenated oils and gums and in particular silicone elastomers can be used as fatty substances.

[0037] As emulsifiers and co-emulsifiers which can be used in the cosmetic composition of the invention, mention may be made of non-ionic, ionic (anionic or cationic) or zwitterionic surfactants, such as, for example, polyglycerol and fatty acid esters, sucrose and fatty acid esters, sorbitan and fatty acid esters, polyoxyethylenated sorbitan and fatty acid esters, fatty alcohol and PEG ethers, glycerol and fatty acid esters, alkyl sulfates, alkyl ether sulfates, alkyl phosphates, alkyl polyglucosides, alkyl polypentosides, dimethicone copolyols, and citric acid derivatives.

[0038] As hydrophilic gelling agents, mention may in particular be made of carboxyvinyl polymers, acrylic copolymers (carbomer) such as acrylate / alkylacrylate copolymers, 2-acrylamido-2-methylpropane acid copolymers, polyacrylamides, polysaccharides such as xanthan gum, guar gum, carrageenans, natural gums such as cellulose gum and its derivatives, starches and their derivatives, clays.

[0039] As lipophilic gelling agents, mention may be made of modified clays such as bentones, metal salts of fatty acids, silica and its derivatives, ethylcellulose, polyamides, dextrose esters.

[0040] The cosmetic composition may also contain active ingredients. As active ingredients, use may in particular be made of depigmenting agents, moisturizing agents, antioxidants, anti-seborrheic agents, anti-inflammatories, anti-acne agents, keratolytic and / or desquamating agents, anti-wrinkle and tightening active ingredients, draining active ingredients, anti-irritant agents, soothing agents, slimming agents such as xanthic bases (caffeine), vitamins and their mixtures, mattifying agents, anti-aging active ingredients such as retinol, and essential oils.

[0041] As preservatives that can be used according to the invention, mention may be made of benzoic acid, its salts and its esters; sorbic acid and its salts; parabens, their salts and esters; triclosan; imidazolidinyl urea; phenoxyethanol; DMDM ​​hydantoin; dia-zolidinyl urea; chlorphenesin; benzyl alcohol; dehydroacetic acid; levulinic acid and derivatives; salicylic acid and its salts; ethylhexylglycerin; organic acids such as gluconolactone.

[0042] As antioxidants which can be used according to the invention, mention may be made of chelating agents such as EDTA and its salts.

[0043] As solvents which can be used according to the invention, mention may be made of water, ethanol, glycerin, propylene glycol, butylene glycol, propanediol, pentylene glycol, hexanediol.

[0044] As fillers that can be used according to the invention, mention may be made of talc, kaolin, mica, serecite, magnesium carbonate, aluminum silicate, magnesium silicate, organic powders such as nylon, PMMA, starches, natural powders such as rice powder. These fillers can also be chemically modified or coated to modify their characteristics.

[0045] As sunscreens that can be used according to the invention, mention may be made of conventionally used UVA and UVB filters such as benzophenones, butyl methoxydibenzoyl methane, octocrylene, octyl methoxycinnamate, 4-methylbenzylidene camphor, octyl salicylate, tacephthalydene dicamphor sulfanic acid, phenylbenzimidazole-sulfonic acid, homosalate, 2-(4-diethylamino-2-hydroxybenzoyl)benzoate, disodium phenyldibenzimidazoletetrasulfonate, Methylenebis-benzotriazolyl tetra-methylbutylphenol, triazine derivatives, Polysilicone-15 and drometrizole tri-siloxane. Mention may also be made of TiO2 and ZnO physical filters in their micrometric and nanometric forms, coated or uncoated.

[0046] As coloring materials which can be used according to the invention, mention may be made of lipophilic dyes, hydrophilic dyes, pigments and nacres usually used in cosmetic or dermatological compositions, and their mixtures.

[0047] As bases and acids which can be used according to the invention, mention may be made of sodium hydroxide, triethanolamine, aminomethyl propanol, potassium hydroxide, citric acid, lactic acid, phosphoric acid.

[0048] As propenetrating agents which can be used according to the invention, mention may be made of alcohols and glycols (ethanol, propylene glycol), ethoxydiglycol, alcohols and fatty acids (oleic acid), fatty acid esters, dimethyl isosorbide.

[0049] The composition according to the invention can be used as a care product, as a cleaning product, and / or as a skin makeup product, as a sun protection product, or as a hair product.

[0050] The invention also relates to a method for manufacturing the emulsifying base described above, according to which:

[0051] - the fatty phase is prepared in the liquid state, - the surfactant is introduced into the fatty phase, with stirring, - before or after adding the surfactant and before adding the water to the fatty phase, the pH of 5% stearoyl glutamate in water is measured separately, - if necessary, the stearoyl glutamic acid / sodium stearoyl glutamate ratio is adjusted by adjusting the pH of the surfactant to 5% in water by adding a base or acid to obtain a pH between 7.8 and 9.2. - when the addition of a base or an acid is necessary, the mass of base or acid to be added is determined based on the quantity of surfactant used during the manufacture of the emulsifying base, - the aqueous phase is prepared by adding the mass of base or acid determined in the previous step, - between 0.2 g and 0.5 g of aqueous phase / g of surfactant are added to the fatty phase, - stirring and resting phases are alternated until the surfactant is completely dissolved.

[0052] According to a preferred embodiment, the stirring phases last between 5 and 15 min, preferably 10 min, while the rest phases last between 2 and 10 min, preferably 5 min.

[0053] Advantageously, the stirring and resting phases are repeated at least twice, preferably 4 times.

[0054] In a particular embodiment, the emulsifying base is subjected to a pelletizing step.

[0055] The invention and the advantages which result from it will become clear from the following examples of embodiment supported by the appended figures. Brief description of the drawings

[0056] [Fig.l] (la to 1g) is a series of photographs of the products obtained at the end of the different stages of the manufacturing process of the emulsifying base.

[0057] [Fig.2] is a photograph of the emulsifying base of the invention in the form of pellets. Detailed description of the invention

[0058] Composition of the emulsifying base The composition of the emulsifying base is reproduced in Table 1 below. iihililililli lilllllllll (|||||||||i

[0059] Process for manufacturing the emulsifying base

[0060] The emulsifying base is prepared as follows.

[0061] The different compounds of the fatty phase are mixed and then the mixture is melted at 80°C. The liquid phase obtained is then stirred at a rate of 250 rpm for a one-liter reactor. Figure 1a is a photograph of the phase obtained at this stage of the process.

[0062] The stearoyl glutamate is then slowly introduced into the fatty phase, still with stirring. Stirring the mixture allows for good dispersion of the powder. The dispersion is shown in Figure 1b.

[0063] The pH of the 5% stearoyl glutamate in water is measured separately. If necessary, the stearoyl glutamic acid / sodium stearoyl glutamate ratio is adjusted by adjusting the pH of the 5% surfactant in water by adding a base or acid to obtain a pH between 7.8 and 9.2. In this case, the mass of base or acid to be added is extrapolated to the quantity of surfactant used during the manufacture of the emulsifying base. The aqueous phase is prepared by adding the mass of base or acid determined above. The aqueous phase is then added to the dispersion in Figure 1b. The amount of aqueous phase added is between 0.2 g and 0.5 g water / g stearoyl glutamate. Below 0.2 g water / g stearoyl glutamate, there is not enough water to allow complete solubilization of the stearoyl glutamate in the fat phase. Above 0.5 g water / g stearoyl glutamate, all of the stearoyl glutamate is solubilized, but excess water appears and settles to the bottom of the mixer.

[0064] The solubilization of stearoyl glutamate in the fatty phase is carried out in several stages of stirring and stopping the stirring (rest).

[0065] Once the water is added, the dispersion, in this example, is stirred for 10 minutes then left to rest for 5 minutes (Figure 1).

[0066] This 10-minute stirring and 5-minute resting step is repeated between 1 and 4 times (Figures 1 d, e, f) until a homogeneous clear product is obtained (Figure 1g).

[0067] This homogeneous and clear mixture can be kept at 90°C for 48 hours in a closed container without any change in macroscopic appearance or chemical composition.

[0068] Pastillage Once the emulsifying base is clear, it can be pelletized without difficulty to obtain pellets that are homogeneous between them throughout the pelletizing operation but also within the same pellet ([Fig.2]).

[0069] Comparative tests Three formulations are prepared, differing from each other only in the pH of the surfactant measured at 5% in water. The emulsifying base is that of Table 1, after adjustment or not of the pH of the surfactant at 5% in water.

[0070] The composition of the formulations is shown in Table 2. The proportions of the ingredients are given as a percentage by mass. Ingredients Fdrmufotfon 1 Fomafetson 2 Formulation 3 Fat phase Polydecene Hydrogenated Trigtycendes ers CB / C10 Isostearafo a'isosteBr^e of apricot kernels Efoy^hexyigiycehn 4.5% 4.5% 3% S-23% SA. 4.5% 4.5% 3% 3% C72% SW 4.5% 4.5% 3%. 3% G.72% s.as% Emulsifier selsrs tB&1“3U 1 conforming to the snsendon ipn to 5% in the esü of tersio-acîlf between 7.S and 9.2} tensto-actrf s 7.8} Emusbnnast according to table 1 not conforming to the twerfoon (phi at 5% of the active ingredient > 9.2) e% Aqueous phase Water 78.2A 7S.2A 78.2% 24 h .Aspect Crème PiancPe brillante Crème blanche: Bright cream: Bright cream bfslianfo Viscosity tcP} 52 aœ 4P SCO 25 5æJ pH 7.3 6.3 'S 1 week Aspect: conform conform conform Viscosity icPI 55 300 385SS 30 800 pH 7,4 53 385SS 30 800 pH 7.4 53 53 ?.4 Aspect 40' conform conform conform mois conform Aspect conform 1 conform conform. Viscosity fov 515® 39 5® 22 8SS p^ 7.6 6.3 7.1 Appearance è 40sC compliant non-compliant Start of creaming f 2sj compliant 3 months Appearance ■compliant compliant compliant Viscosity {cP} 47 3® 31 ASS 14 4SS non-compliant pS 7.5 fi, 3 6.5 non-compliant Appearance: at AlVC______________ compliant non-compliant compliant .

[0071] It is clear from the above that formula 1, whose pH at 5% in the surfactant water is between 7.8 and 9.2, has a viscosity close to 50,000 cP, which corresponds to what is expected. The results also show that the stability of formula 1 is good over time.

[0072] Examples of cosmetic formulations Anti-aging serum ingredient Demineralized water Hydroxypropyl guar % m / m Qsp 100.0 1.0 Glycerin 2.0 Xanthan gum Pulluian EMULSIFYING BASE ACCORDING TO THE INVENTION Preservative 0.2 2.0 3.0 0.7 Undecane, tridecane 10.0 Active an':-age 1.0 Pearls 0.5 Citric acid qs Sunscreen body milk SPF 30

[0074] [Tables4] fnQrétôîem Demineralized Water Qsp100 00 Sptîmgomonas Ferment Extract 8.15 Ethÿlhexyl Tdazone 3.00 Diethylassmo Hydroxybenzoyl Hexyi Benzaate 5.80 Bis-EihylhexytoxypbKWl Methoxyphenyl Tnazine 2.00 Ethylhexyl Savate 5.00 Oespprqsÿi Etfiyfcefete 1.50 Dibutyl Adipate 6.00 Discpropyt Sebacate 9.00 Butyl Octyl Safâate 2.50 PhehoKyeihanûi, Ethyihexylglycenn 8.70 B^énste de glycercl _________1.50 EMULSIFMNANT BASE SECONDARY TO LWENT|OH 5.00 DiÊsostea wl pWWcsryi-3 dimer dilinaleate 2 G0 Copemaaa centra (camauba) wax. ©ryza sativa frice) bran wi 3.00 Butylene gtycsl 4.00 Actrf moisturizer 2 00 Citric Acid qs Day cream :Alc®d cêtyhqæe 3.0: iJc0ba esters, hehsnthus annu^s (sonOow^} seed wass, J : acacia dectweos flwer J CW-tS fagkcendes 5.0i : DscapjyM etoer 18.0: Hwle rfégetate n^drogenèe 5.® CcnseivaSeat 1.0 : BASE E^ULSIOMNAKTE^ ACCORDING TO WENTOî 5'$ Eao '.fersH^efaîfsee Qsp 10C 0 Acacia senega! gum \anthan gmv G.4: :Ol¥cenne 5.0; AciiSe citfiqcê _______________________________________________ C 5 AcM tensor 1.0 Parto> C2 ;Nà£T^ 12^ Sending agent 2 0

Claims

Claims

1. Use as an emulsifying base in a cosmetic or pharmaceutical formulation, of a composition comprising a fatty phase, an aqueous phase, and a surfactant containing a mixture of alkali metal stearoyl glutamate and stearoyl glutamic acid, characterized in that the surfactant has a pH measured at 25°C in a 5% by mass solution in water of between 7.8 and 9.2 and in that the composition comprises between 0.2 g and 0.5 g of aqueous phase / g of surfactant.

2. Use according to claim 1, characterized in that the alkali metal is sodium.

3. Use according to claim 1, characterized in that the alkali metal stearoyl glutamate is sodium stearoyl glutamate.

4. Use according to one of the preceding claims, characterized in that the surfactant represents between 5 and 12%, advantageously between 7 and 9% by mass of the emulsifying base.

5. Use according to one of the preceding claims, characterized in that the fatty phase comprises a wax derivative obtained by the simultaneous transesterification reaction of a mixture comprising jojoba wax and sunflower wax, in the presence of polyglycerol-3.

6. Use according to claim 5, characterized in that the wax derivative represents between 20 and 40%, preferably between 24 and 35% by mass of the fatty phase.

7. Use according to one of claims 5 or 6, characterized in that the fatty phase further comprises at least one C16-C18 fatty alcohol and glycerol palmitostearate.

8. Use according to claim 7, characterized in that the at least one C16-C18 fatty alcohol and the glycerol palmitostearate represent respectively between 35 and 50% by mass of the fatty phase and 20 to 30% by mass of the fatty phase.

9. Use according to one of the preceding claims, characterized in that the composition is in the form of individualized solid particles.

10. Use according to claim 9, characterized in that the individualized solid particles are in the form of scales or pellets of a size greater than or equal to 1 millimeter.

11. Cosmetic composition comprising the emulsifying base such as described in one of claims 1 to 10.

12. Cosmetic composition according to claim 11, characterized in that the emulsifying base represents between 1 and 8% by mass of the composition, preferably between 2 and 5% by mass.

13. Process for manufacturing an emulsifying base for cosmetic or pharmaceutical formulation comprising a fatty phase, an aqueous phase, and as surfactant, a mixture of sodium stearoyl glutamate and stearoyl glutamic acid, according to which: - the fatty phase is prepared in the liquid state, - the surfactant is introduced into the fatty phase, with stirring, - before or after adding the surfactant and before adding the water to the fatty phase, the pH at 5% in water, of the stearoyl glutamate is measured separately, - if necessary, the stearoyl glutamic acid / sodium stearoyl glutamate ratio is adjusted by adjusting the pH of the surfactant at 5% in water by adding a base or acid to obtain a pH between 7.8 and 9.2.- when the addition of a base or an acid is necessary, the mass of base or acid to be added is determined according to the quantity of surfactant used during the manufacture of the emulsifying base, - the aqueous phase is prepared by adding the mass of base or acid determined in the previous step, - between 0.2 g and 0.5 g of aqueous phase / g of surfactant is added to the fatty phase, - stirring and resting phases are alternated until the surfactant is completely dissolved.

14. Method according to claim 13, characterized in that the emulsifying base is subjected to a pelletizing step.

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