FR2764294A1 - ACARIOGENIC POLYSACCHARIDES AND PROCESS FOR THE MANUFACTURE THEREOF - Google Patents

Abstract

The invention concerns polysaccharides obtained by extrusion, characterised in that they are directly acariogenic without requiring to be subjected, after extrusion, to a complementary treatment to eliminate the fermentable compounds causing dental decay. The invention also concerns a method for making said polysaccharides.

Description

ACARIOGENIC POLYSACCHARIDES AND
PROCESS FOR THE MANUFACTURE OF THESE POLYSACCHARIDES
The subject of the invention is acariogenic polysaccharides which can be used in particular as a texture agent in products intended to be ingested by humans or animals, that is to say in particular in food products, and in certain pharmaceutical or veterinary products. .

 The invention also relates to a process for the production of said polysaccharides as well as the application of these polysaccharides in the preparation of acariogenic compositions intended to be ingested by humans or animals.

 By the expression "compositions intended to be ingested by humans or animals", is meant compositions or products intended for ingestion and for oral administration such as various foodstuffs such as confectionery, pastries, ice creams , chews, chewing gum, prepared animal food, as well as pharmaceutical, veterinary, dietetic or hygienic products such as for example elixirs, cough syrups, tablets or tablets, lozenges, oral hygiene solutions, pastes and toothpaste gels.

 Over the past decade, there has been increasing interest in the manufacture of acariogenic products capable of replacing conventional sugars, such as sucrose, glucose or fructose, in food products and in certain products. pharmaceutical or veterinary.

 By "acariogenic products" is meant products which exhibit less acidification by bacteria in the mouth than conventional sugars such as sucrose, glucose or fructose. The acariogenic effect is in fact due to the presence, in the oral cavity, of bacteria which metabolize sugars and lead to the production of acid. The latter dissolves hydroxyapatite from dental enamel and creates cavities there.

 Such acariogenic products are for example hydrogenated monosaccharides, hydrogenated disaccharides, hydrogenated or non-hydrogenated oligosaccharides and hydrogenated polysaccharides.

 As an example of hydrogenated monosaccharides, mention may be made of sorbitol, xylitol, erythritol, mannitol, arabitol and threitol.

 The acariogenic disaccharides are represented in particular by maltitol, lactitol, hydrogenated isomaltulose (known under the brand PALATINITR or more generally under the name ISOMALT) and isomaltitol.

Hypocariogenic oligosaccharides are also already known. Mention may thus be made, for example, of maltitol syrups containing approximately 50-55% maltitol on dry matter, such as for example LYCASIN 80/55 sold by the
Applicant. These hydrogenated oligosaccharides have been especially developed for application in boiled sweets. It is indeed quite obvious that one requires hypocariogenic properties much more marked in an application such as the manufacture of candies sweets sugars which, by their very essence, are likely to be in long contact with the teeth, than in a application such as for example the manufacture of very diluted liquid products.

 As other examples of hypocariogenic oligosaccharides, mention may also be made of maltitol syrups containing approximately 72-78% maltitol on dry matter, such as, for example, MALTISORBR 100, MALTIDEXR 200, MALBIT and FINMALTR.

However, these syrups cannot be used satisfactorily in certain applications such as those for boiled sweets, jellies, cough syrups, where there is another drawback, which resides in the risks of crystallization incurred during l use of these syrups.

Polydextroses purified by chromatography (WO
A-92 121 79), hydrogenated (WO-A-92 14761) and hydrogenated and chromatographed (US-A-5,424,418) are yet another example of acariogenic products.

Finally, a last category of acariogenic products is constituted by hydrogenated polysaccharides obtained by enzymatic hydrolysis of dextrins or polyglucoses (EP-A-561.088, EP-A-561.090, EP-A-561.089,
EP-A-368.451 and JP-A-62019501).

 According to documents US-A-5,458,892 and US-A5,236,719, additional treatments such as chromatography, glucose oxidase treatment, gel permeation, ultrafiltration, fermentation with yeasts are however necessary to make commercial dextrins non-cariogenic .

 From all of the above, it appears that there is therefore an unmet need for highly viscous, non-cariogenic polysaccharides obtained using a simpler process than those already known in the prior art.

 Against all expectations, and surprisingly and unexpectedly, the Applicant has discovered that it is possible, by extrusion, to obtain directly acariogenic polysaccharides, and this without necessarily hydrogenating them (hydrogenation sometimes creating a regulatory constraint for certain applications ) and without necessarily needing to hydrolyze them enzymatically and to separate or hydrogenate the products resulting from the hydrolysis in accordance with the processes of the prior art.

The invention therefore relates, first of all, to a process for manufacturing acariogenic polysaccharides, characterized in that it comprises the successive stages consisting in
- prepare an acidified starch, dehydrated to a humidity less than or equal to 6%, preferably less than or equal to 4%, and more preferably less than or equal to 2%,
extruding the acidified starch thus dehydrated at a temperature between 140 and 230 "C, preferably between 150 and 2100C,
- collect the acariogenic polysaccharides thus obtained.

 One of the objects of the invention is therefore to provide polysaccharides which have the property of being able to be qualified as non-cariogenic according to a B test.

 Another object of the invention is to provide an acariogenic composition comprising 45 to 50% by weight of these polysaccharides and 50 to 55% of maltitol.

Test B is a test developed by the Company
Applicant in order to control the non-cariogenic character of the hydrogenated hydrolysates marketed from 1979 under the name LYCASINh 80/55. This simple test is based on the in vitro determination of the acidification of a given quantity of hydrogenated starch hydrolyzate after inoculation of the medium with saliva. It is based on the appreciation of the drop in pH over time of a culture broth containing the product to be tested, after therefore seeding with saliva from several donors, compared to a control culture broth containing no carbohydrate . It should be emphasized that this test is not sufficient to characterize in an absolute way the non-cariogenicity of a product, because its results may vary, for example, depending on the quality of the saliva used, but it nevertheless allows for comparisons to be made. valid between different products.

 The detailed procedure for this test is as follows.

 A series of tubes containing 10 ml of a nutritive culture medium (trypticase medium at 2% dry matter) without sugar at pH 7 is prepared, and these tubes are sterilized by autoclaving at 120 "C for 20 minutes .

 In a first series of five tubes, 1 ml of sterile water is introduced to make a control series.

 In a second series of five tubes, 1 ml of an 18 t (W / V) solution of the product to be tested is introduced.

 Then the five tubes of each series are seeded with the same volume of 0.2 ml per tube of a dilution of one fifth of the human saliva obtained by sampling from five donors.

 The formation of acids is then monitored by measuring the pH, a first measurement being carried out before incubation and the other measurements being carried out after incubations at 30 ° C. of 3, 6, 13, 18 and 21 hours respectively.

 For a product to be considered non-cariogenic within the meaning of this test B, the difference in pH observed between the control after 21 hours and the product to be tested after 21 hours must not be too pronounced and, in practice, at most equal to 1 pH unit.

 One of the great merits of the invention is to provide polysaccharides which have the property of being non-cariogenic within the meaning of this test B, whereas they have not undergone any known treatment to make them acquire this property.

 The Applicant has discovered and demonstrated that the acariogenic nature of the polysaccharides obtained by extrusion was a direct function of the moisture content of the acidified starch to be extruded.

 During the preparation of starch and during its transformation by extrusion in the molten phase, it is therefore necessary to work in a weakly hydrated acid medium, less than or equal to 6% in water, preferably less than 4% in water and more preferably less or equal to 2% in water, probably in order to disadvantage the hydrolysis reactions and to create branches or ramifications between the molecules.

 Methods consisting in extruding a starch have already been proposed in the literature.

 Thus, documents EP-A-538,146 and EP-A-530,111 describe the preparation of an indigestible dextrin, by extrusion of potato starch and corn starch respectively. These documents thus aim at obtaining products which are not very digestible for the body, called "low calorie", and which act in the body as dietary fiber.

Their object is therefore very far from that of the present invention, which is to prepare a hypocariogenic product, with technological aptitudes usable both in candies, chewing gum and toothpaste, as in pharmaceutical and veterinary drinks and elixirs .

 On the other hand, it can be emphasized that said documents do not describe or suggest the importance of the moisture content of the starch to be extruded. Thanks to a water content of the acidified starch less than or equal to 6%, and preferably less than or equal to 4% and more preferably less than or equal to 2%, directly non-cariogenic polysaccharides are obtained without it being necessary to subject them to additional treatment in the sense defined above.

 The first step of the process according to the invention therefore consists in preparing a dehydrated acidified starch in order to carry out its transformation by extrusion.

 The botanical origin of starch is indifferent.

Starch can therefore come from wheat, corn or potato. However, it is advantageously preferred to use wheat starch.

 The acid used to acidify the starch can be chosen from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and citric acid. However, given the fact that citric acid is capable of generating undesirable ester bonds, since they are responsible for bitterness, and that the handling of sulfuric acid poses obvious safety problems, it is preferred to use in the context of the invention hydrochloric acid, phosphoric acid or nitric acid.

 The amount of acid used in the process according to the invention is between 5 and 50 meq W / kg dry, and preferably between 10 and 30 meq H / kg dry.

 It is important that the distribution of the acid in the starch is as homogeneous as possible.

 Different techniques can be used for the acidification of starch, such as discontinuous or continuous acidification, in the dry or liquid phase.

However, the acidified starch being intended to be used in a continuous modification process
(extrusion), it is preferred in the present invention to use a means of continuous acidification to carry out a process as continuous as possible, and thus limit non-productive operations (loading, unloading, emptying).

 The acidification carried out, the starch is dehydrated in order to favor, during the transformation by extrusion, the repolymerization reactions. During this drying step, care should be taken not to favor the hydrolysis reactions because the different parameters favorable to dextrinification (high humidity, temperature, acidity) are combined. These conditions favor undesirable hydrolysis reactions which are characterized by an increase in the levels of reducing sugars.

 The Applicant has been able to demonstrate that priority should be given, during this step, to continuous type drying techniques enabling the desired humidity to be reached in a residence time of the order of a minute, or even a second. and thus minimize the starch hydrolysis reactions.

 Thus dehydrated at a humidity less than or equal to 6%, preferably less than or equal to 4% and more preferably less than or equal to 2%, the acidified starch can be extruded at a temperature between 140 and 230 "C, preferably between 150 and 2100C, to give directly acariogenic polysaccharides.

 The invention therefore relates to acariogenic polysaccharides obtained by extrusion of a dehydrated acidified starch having a moisture content less than or equal to 6%, preferably less than or equal to 4%, and more preferably less than or equal to 2%.

 The polysaccharides obtained by extrusion in accordance with the invention are characterized in that they are directly acariogenic without it being necessarily necessary to subject them, after extrusion, to an additional treatment intended to remove the compounds capable of being transformed into acids. by fermentation, that is to say the compounds responsible for the appearance of dental caries.

 In the context of the present invention, by “complementary treatment intended to eliminate the compounds capable of being transformed into acids by fermentation” is meant, without this list being limiting, enzymatic hydrolysis, chromatography, treatment with glucose oxidase , gel permeation, ultrafiltration, yeast fermentation, etc.

 According to another characteristic of the invention, the polysaccharides obtained by extrusion are directly acariogenic without it being necessary to subject them, after extrusion, to hydrogenation.

 The acariogenic polysaccharides according to the invention have a molecular weight by weight Mw of between 2,000 and 10,000 g / mole and preferably between 3,000 and 7,000 g / mole. They have a molecular weight Mn of between 900 and 5,000 g / mole, preferably between 1,000 and 2,500 g / mole.

 The technique used for the determination of molecular weights is size exclusion chromatography. It is based on the selective retention of molecules of the solute according to their size, due to their penetration into the pores of the stationary phase.

 The polysaccharides in question also have a content of free reducing sugars of between 0 and 20% and a free glucose level of between 0 and 5%, preferably between 0.01 and 2.5%.

 The content of reducing sugars is expressed in glucose, by weight relative to the dry weight of product analyzed, and it is measured by the BERTRAND method.

 By their physicochemical and physiological properties, the polysaccharides in accordance with the invention have a certain and immediate interest in particular in the preparation of acariogenic compositions intended to be ingested by humans or animals.

 Thus, an acariogenic composition comprising 45 to 50 by weight of polysaccharides in accordance with the invention and 50 to 55% by weight of maltitol finds an advantageous application in the manufacture of boiled sugar candies.

 The polysaccharides obtained in accordance with the invention can then undergo a series of purification steps aimed at discoloring them. Two means of bleaching by adsorption can be used, that employing pulverulent or granular activated carbon and that employing adsorbent resins.

ICUMSA (International Commission for
Uniform Methods of Sugar Analysis) makes it possible to determine the coloration of the products synthesized from starch or their hydrogenated equivalents.

The principle consists in filtering a solution on a membrane to eliminate turbidity. The absorbance of the filtered solution is measured at a wavelength of 420 nm and the coloring of the solution is calculated by the following formula
ICUMSA staining = As x 1000/1 x C IU in which
- As is the absorbance of the solution,
- 1000 is a multiplying factor,
- l is the length of the optical path,
- C is the concentration in g / ml of the solution.

 In the case of a bleaching step using pulverulent activated carbon, the Applicant has determined that high bleaching percentages can be obtained by using large porous volumes of mesopores (pore radii between 1.5 and 25 nm and in particular between 4 and 20 nm).

Successive discolourations can be implemented to optimize the discoloration. However, to avoid the loss of activated carbon, it is preferred in the context of the invention, to use recyclable supports such as columns of granular blacks or specific resins (adsorbents)
The adsorbent resins are non-ionic or very weakly ionic polymers, highly rigid, and macro-crosslinked. They consist of polystyrene crosslinked to divinylbenzene in the presence of a blowing agent.

They are in the form of spherical grains of 0.5 to 1.5 mm in diameter or in the form of granules with specific surfaces up to 1300 m / g, comparable to active carbon.

The use of MACRONET MN 600 type resins
(marketed by the company PUROLITE) is particularly preferred for discoloring the extruded products in accordance with the invention.

 The extruded product, then purified and previously filtered and then demineralized, is then optionally subjected to molecular sieving and then to catalytic hydrogenation or to catalytic hydrogenation and then to molecular sieving. This molecular sieving step can consist, for example, of a chromatographic separation step or a separation step on membranes.

In the context of the present invention, the molecular sieving step is intended to remove the small molecules from the extruded product. It thus contributes to improving the thermal stability of the product and to increasing its viscosity. This molecular sieving step makes it possible to collect a fraction consisting of polysaccharides having molecular weight characteristics determined as a function of the viscosity sought in a given application. So investigations by the
Applicants have made it possible to show that, for the manufacture of boiled sweets, the fraction of polysaccharides having an Mw of approximately 5,000 g / mole and an Mn of approximately 2,500 g / mole gave very good results.

 In the context of the present invention, the hydrogenation step is intended to improve the thermal stability in the case where, for a given application, the presence of reducing sugars is harmful (which is the case for example in the application cooked sugar candy).

 In general, molecular sieving is carried out on a syrup previously filtered and then demineralized and concentrated to a dry matter practically between 20 and 60%, preferably between 25 and 55%.

 The chromatographic fractionation step is carried out in a manner known per se, discontinuously or continuously (simulated moving bed), on strong cationic resins of macroporous type, preferably loaded with alkali or alkaline earth ions such as calcium and magnesium but more preferably using sodium or potassium ions.

 Examples of such methods are described in particular in US Patents 3,044,904, 3,416,961, 3,692,582, FR 2,391,754, 2,099,336, US 2,985,589, 4,024,331, 4,226,977, 4,293,346, 4,157,267, 4,182,623, 4,332,623, 4,405,455, 4,412,866, 4,422,881 and WO 92/12179.

 According to a preferred embodiment, the chromatographic fractionation is carried out using the method and apparatus described in US Patent No. 4,422,881, of which the Applicant Company is the holder.

Regardless of the chromatographic method used, preference is given, with regard to the adsorbent, to a strong cationic resin used in sodium or potassium form of macroporous type. The resins are advantageously of homogeneous particle size and between 100 and 800 micrometers.

 The choice of the parameters of the chromatographic fractionation is within the reach of the skilled person.

 The choice of these parameters is made in such a way that the fraction containing the polysaccharides according to the invention has a molecular weight by weight of between 3,000 and 7,000 g / mole and preferably between 4,500 and 5,500 g / mole, and a mass molecular number between 1,000 and 4,000 g / mole and preferably between 2,000 and 3,000 g / mole.

 For the hydrogenation stage, both ruthenium-based catalysts and Raney nickel catalysts can be used. However, it is preferred to use Raney nickel catalysts which are less expensive.

 In practice, from 1 to 10% by weight of catalyst is used relative to the dry matter of sugar subjected to hydrogenation. The hydrogenation is preferably carried out on syrups whose dry matter is between 15 and 50%, in practice close to 30 to 45%, under a hydrogen pressure of between 20 and 200 bars. It can be carried out continuously or discontinuously.

 When operating discontinuously, the hydrogen pressure used is generally between 30 and 60 bars and the temperature at which the hydrogenation takes place is between 100 and 1500C. Care is also taken to maintain the pH of the hydrogenation medium by the addition of sodium hydroxide or sodium carbonate for example, but without exceeding a pH of 9.0. This procedure avoids the appearance of cracking or isomerization products.

 The reaction is stopped when the content of reducing sugars in the reaction medium has become less than 1%, more preferably less than 0.5% and more particularly less than 0.1%.

 After the reaction medium has cooled, the catalyst is removed by filtration and the hydrogenated polysaccharides are demineralized respectively on cationic and anionic resins.

 Other characteristics and advantages of the invention will appear clearly on reading the examples which follow, given by way of indication but in no way limitative.

EXAMPLE 1
Wheat starch is acidified with hydrochloric acid at a rate of 21.7 meq H / kg dry, then dried at different residual humidities: 6%; 3%; 1.5%.

This raw material is then introduced into a CLEXTRAL BC92 extruder having the following technical characteristics
- Smooth cylindrical scabbard of fixed length
(L 1000 cm; L / D 10),
- Bivis; self-cleaning; multi-threads; corotatives (diameter of the screws: 10 cm),
- Two sleeves heated by induction and cooled by a circulation of water,
- Maximum intensity of use: 400 A,
- Maximum speed of rotation: 400 rpm,
- Maximum operating pressure: 180 bar, and using the following operating conditions
- Rotation speed: 400 rpm,
- Temperature: 160 OC.

 The product is recovered and characterized in terms of molecular weights by weight and number, and of result in test B (acariogenicity).

 The results are collated in Table III below.

TABLE III
TEST No. 1 2 3 H2O (%) 6 3 1.5
Mw g / mole 3420 3830 4150
Mn g / mole 1060 1130 1290
Test B Good Good Good
Test B Good Good Good (+ 50% maltitol)
The extruded product is then purified before being subjected to chromatographic separation. The results, after chromatography, are collated in the following Table IV.

TABLE IV
TEST N "Mw g / mole Mn g / mole
1 4560 2580
2 4780 2640
3 5000 2500
The product is then concentrated to a dry matter of approximately 40% then catalytically hydrogenated at a rate of reducing sugars of less than 0.5%.

EXAMPLE 2
Sugar-free sweets are made from three compositions comprising approximately 50% maltitol
(A) a maltitol syrup sold by the
Applicant under the name of LYCASINR 80/55
(B) polysaccharides obtained by a conventional process (polysaccharides obtained by subjecting a dextrin to an enzymatic treatment) added with an equivalent quantity of mastitol
(C) polysaccharides according to the invention added with an equivalent amount of maltitol.

 The results are collated in Table V below.

TABLE V
ABC product
Temperature of 150 150 150 cooking ("C)
Residual water (%) 3.9 2.6 2.3
Glass transition 26.5 49.6 55
Tg ("C)
Stability (*) + ++ ++
Quality of the packaging - fully semi-semilage waterproof waterproof waterproof
Stability is evaluated after 10 days at 20 "C and 66% RH
+: collage
++: slightly deformed and sticky - Trace of microcrystals.

 It can be seen that the sugars cooked without sugar produced from composition (C) according to the invention exhibit behaviors similar to those of conventional sweets of the prior art.

 Their behavior differs greatly on the other hand from that of cooked sugars made from maltitol syrups type LYCASINR 80/55 which are particularly hygroscopic and tend to flow out when taken up in water.

In addition, Table V reveals the following other advantages, with regard to the use of the composition (C) according to the invention in the manufacture of cooked sugars
- surface microcrystallization which reduces the cost of packaging;
- a decrease in the cooking temperature to obtain a cooked mass of less than 97% dry matter
(reduction in energy cost) whereas for LYCASINR 80/55 (product A), it would be necessary to heat above 1500C to bring the residual water content to a value below 3%;
- an increase in the glass transition temperature (reduction in production time).

Claims (10)

RESELL I CAT IONS  1. A method of manufacturing acariogenic polysaccharides characterized in that it comprises the steps consisting in  - Prepare an acidified starch dehydrated to a humidity less than or equal to 6%, preferably less than or equal to 4% and more preferably less than or equal to 2%;  - Extruding the acidified starch thus dehydrated at a temperature between 140 and 230 "C, preferably between 150 and 210" C;  - collect the acariogenic polysaccharides thus obtained.  2. Acariogenic polysaccharides obtained by extrusion of a dehydrated acidified starch having a moisture content less than or equal to 6%, preferably less than or equal to 4% and more preferably less than or equal to 2%.  3. Polysaccharides obtained by extrusion, characterized in that they are directly acariogenic without it being necessary to subject them, after extrusion, to a complementary treatment intended to eliminate the fermentable compounds in acids.  4. Polysaccharides obtained by extrusion, characterized in that they are directly acariogenic without it being necessary to subject them, after extrusion, to hydrogenation.  5. Polysaccharides according to any one of claims 2 to 4, characterized in that they have a molecular weight by weight, of between 2,000 and 10,000 g / mole and preferably between 3,000 and 7,000 g / mole .  6. Polysaccharides according to any one of claims 2 to 5, characterized in that they have a number-average molecular mass of between 900 and 5,000 g / mole and preferably between 1,000 and 2,500 g / mole.  7. Polysaccharides according to any one of claims 2 to 6, characterized in that they have a reducing sugar level of between 0 and 20%.  8. Polysaccharides according to any one of claims 2 to 7, characterized in that they have a free glucose level of between 0 and 5%, preferably between 0.01 and 2.5%.  9. Use of polysaccharides obtained by extrusion of a dehydrated acidified starch having a moisture content less than or equal to 6%, preferably less than or equal to 4% and more preferably less than or equal to 2%, as acariogenic compound in the preparation acariogenic compositions intended to be ingested by humans or animals.  10. acariogenic composition, characterized in that it comprises 45 to 50% by weight of polysaccharides according to any one of claims 2 to 8 and 50 to 55% by weight of maltitol.