MXPA97005399A - New manufacturing procedure of palatini - Google Patents

Abstract

The object of the invention is a novel process for the manufacture of palatinitol, in which: in a first step, the epimerization of isomaltose is carried out under conditions which make it possible to obtain a mixture of alpha-D-glucopyranosyl- (16) -D-mannose and of isomaltose, in a second stage, the catalytic hydrogenation of this mixture, and in a third stage, the isomaltitol chromatographic depletion of this hydrogenated mixture in order to obtain an approximately equimolecular mixture of alpha-D-glucopyranosyl- (16) -D -sorbitol and of alpha-D-glucopyranosyl- (16) -D-manit

Description

NEW MANUFACTURING PROCEDURE OF PALATINITOL The present invention relates to a new process for the manufacture of palatinitol. It relates more particularly to a process for the manufacture of palatinitol from isomaltose or α-D-glucopyranosyl- (1α6) -D-glucose. Palatinitol is a low-calorie, low-cariogenic sweetener that is obtained up to now by the catalytic hydrogenation with neutral pH of isomaltulose or α-D-glucopyranosyl- (1α6) -D-fructose. Isomaltulose is obtained by enzymatic isomerization, with the aid of a saccharose glycosyltransferase of sucrose or a-D-glucopyranosyl- (1? 2) - -D-fructofuranoside. It is thus sucrose that constitutes the raw material for obtaining palatinitol, mixed in approximately equimolar proportions, of aD-glucopyranosyl- (1-6) -D-sorbitol (GPS or isomaltitol) and of a-D-glucopyranosyl- (1-6). ) -D-mannitol (GPM). Palatinitol, also called isomalt, is marketed especially by the company Süddeutsche Zuc er AG under the name Palatinit®. We can refer, among other documents that concern the obtaining and properties of palatinitol, to the work "Alternative Sweeteners" published in 1986 by LYN O'BRIEN NABORS, chapter 11, pages 217 to 244. Concerned about developing a procedure that allows obtaining the palatinitol from another raw material other than sucrose, the Applicant Company has found that this goal can be achieved by a process employing isomaltose or cv-D-glucopyranosyl- (1? 6) -D-glucose. According to the present invention, palatinitol is obtained by a process characterized by the fact that. - in a first stage, the epimerisation of isomaltose is carried out under conditions that make it possible to obtain a mixture of aD-glucopyranosyl- (1? 6) -D-mannose and isomaltose, in a second stage, catalytic hydrogenation is carried out of this mixture, in a third stage, isomaltitol chromatographic impoverishment of this hydrogenated mixture is proceeded in order to obtain an approximately equimolecular mixture of aD-glucopyranosyl- (1? 6) -D-sorbitol and of a-D-glucopyranosyl- (1) 6) -D-mannitol. If it is reasonable to imagine that palatinitol could be obtained from sucrose, the technician can not wait for this same palatinitol to be obtained from isomaltose, which is obtained from glucose and thus from various and varied starches.

In fact in the first case, the sucrose whose formula developed comprises a fructose motif will give, in a manner known per se by enzymatic isomerization, the corresponding ketose, that is isomaltulose. And it is known to the artisan that the hydrogenation of such a ketose leads to the formation of two corresponding itols in substantially equimolar proportions. Thus, the fact that the formula of sucrose resembles that of palatinitol allows us to presume the result. On the other hand, the process of the invention does not employ a starting product whose formula resembles that of the palatinitol sought. In fact, both isomaltose, glucose or starch have a structure that has no fructose motif and is therefore far removed from that of palatinitol. The process of the invention then makes it possible to exempt the obligation to use sucrose as a raw material in the manufacture of palatinitol since isomaltose can be obtained easily from glucose and then from various and varied starches, which have been extracted from cereals or from tubers. A process for obtaining isomaltose from glucose or a corn syrup is described, for example, in French patent application 2,515,186.

In the process of the invention, it is preferred to employ crystallized isomaltose, although syrups very rich in isomaltose are equally suitable if it is recognized that maltitol or iso altotriitol may be present in the palatinitol. These last two compounds come from the hydrogenation of maltose or isomaltotriose, which represent the dominant impurities of the syrups very rich in isomaltose. In the process of the invention the epimerization of isomaltose can be carried out as described in the Japanese patent application 63-162698 with the aid of a metal salt and an amine but it is preferably conducted in the manner described in Japanese patent application 63-96195 and which consists of reacting with a pH comprised between 2.5 and 4, in the presence of molybdic anhydride or hexavalent molybdenum salts, at a temperature between 90 ° C and 140 ° C, an aqueous solution of isomaltose. Preferably, ammonium molybdate is used in a proportion of about 0.1 to 1.5 weight percent with respect to isomaltose. Preferably, the epimerization of the isomaltose is also carried out in the form of an aqueous sugar solution containing 10 to 70 percent isomaltose. The epimerization conditions (essentially catalyst rate, duration of the epimerization and reaction temperature) are adjusted, so as to obtain a mixture of isomaltose and oD-glucopyranosyl- (1? 6) -D-mannose, containing to 40 percent of this last compound. Mixtures containing less than 10 percent are not economical to treat and mixtures containing more than 40 percent contain too many impurities that form under extreme epimerization conditions. It is preferred to work under conditions that allow to obtain from 20 to 35 percent of α-D-glucopyranosyl- (1 6 6) -D-mannose and more preferably from 25 to 35 percent of this compound. The mixture thus obtained is demineralized on the ion exchange resins to remove the salts that have served as a catalyst. In the process of the invention, the hydrogenation of the epimerized mixture is carried out in a manner known per se, continuous or discontinuous, under a hydrogen pressure of 30 to 200 bar, at a temperature of 80 to 150 ° C in the presence of a catalyst based on of nickel or ruthenium and at a pH close to neutrality. A hydrogenation conducted at a pH lower than 4.0 would result in partially hydrolyzing isomaltose in glucose and α-D-glucopyranosyl- (1α6) -D-mannose in glucose and mannose with the onset of sorbitol and mannitol. A hydrogenation at a pH greater than 9 would result in undesirable, the formation of aD-glucopyranosyl- (1? 6) -D-sorbitol and not of aD-glucopyranosyl- (1? 6) -D-mannitol from aD -glucopyranosyl- (1? 6) -D-mannose. In general, hydrogenation is pursued until the content of reducing sugars, measured by the Bertrand method, becomes less than 1 percent and preferably less than 0.5 percent. After the hydrogenation step, the syrups obtained are purified to remove the catalyst, by filtration then demineralization on ion exchange resins, and the syrups are concentrated in a dry material comprised between 10 and 70 percent for their chromatography. These hydrogenated syrups then show an average composition having 10 to 40 percent aD-glucopyranosyl- (1? 6) -D-mannitol and 60 to 90 percent aD-glucopyranosyl- (1-6) -D- sorbitol. Syrups containing from 25 to 35 percent of a-D-glucopyranosyl- (1? 6) -D-mannitol and from 65 to 75 of a-D-glucopyranosyl- (1? 6) -D-sorbitol are preferred. In the process of the invention, the impoverishment of α-D-glucopyranosyl- (1α6) -D-sorbitol of the hydrogenated syrups is followed by chromatography. Generally, when a chromatographic step is used that must carry out the separation of two components of a binary mixture, the chromatography is conducted in such a way that the two components are separated as completely as possible, that is, in order to obtain a fraction A which contains only very little component B and a fraction B which contains only very little component A. In the process of the invention, the depletion of the epimerized mixture of o'-O-glucopyranosyl ~ (1? 6) -D-sorbitol is conducted, on the contrary, so as to obtain an excluded fraction containing an approximately equimolar proportion of aD-glucopyranosyl- (1? 6.) -D-sorbitol and of aD-glucopyranosyl- (1? 6) -D-mannitol, the other adsorbed fraction being composed of very pure aD-glucopyranosyl- (1? 6) -D-sorbitol. By approximately equimolecular, it is understood from 40 to 60 percent and more preferentially, from 45 to 55 percent of one of the two compounds with respect to the total mass of the two compounds. This way of doing so has the advantage of directly obtaining palatinitol, without having to resort to remixes of pure fractions of ar-D-glucopyranosyl- (1? 6) -D-mannitol and of a-D-glucopyranosyl- (1? 6) - D-sorbitol in the ideal proportions. The chromatographic fraction containing the o; -D-glucopyranosyl- (1? 6) -D-sorbitol surplus can be marketed in the state after the concentration, but it is preferred to crystallize pure ar-D-glucopyranosyl- (1-6) -D-sorbitol that is dried .

The α-D-glucopyranosyl- (1 6 6) -D-sorbitol is in fact an excellent mass sweetener, low in carcinogen and low in calories, occurring in the form of a crystalline, anhydrous and white powder that spills freely. This chromatographic step is carried out very easily on an industrial scale by applying the hydrogenated mixture on a column charged with cation exchange resins of the polystyrene-sutened type cross-linked to divinylbenzene. These resins, in order to adapt to the chromatography, must have a very fine and very homogeneous granulometry, advantageously comprised between 150 and 400 microns, and for their use, they are exchanged under the alkaline or alkaline-earth form. The mixture applied on the column is then fractionated by washing the resin with water. It is then surprisingly found that although aD-glucopyranosyl- (1? 6) -D-mannitol and aD-glucopyranosyl- (1? 6) -D-sorbitol have analogous structures and strictly identical molecular weights, a large migration The fastest reaction of α-D-glucopyranosyl- (1? 6) -D-mannitol into the resin results in a correlated impoverishment of α-D-glucopyranosyl- (1? 6) -D-sorbitol in the mixture subjected to chromatography. It is sufficient after decanting the resin at the beginning of the washing cycle, the amount of material strictly necessary to obtain in an approximately stoichiometric ratio that is that of palatinitol, the components of the mixture subjected to chromatography. The fraction representing the end of the washing cycle then contains a high proportion of α-D-glucopyranosyl- (1α6) -D-sorbitol, generally comprised between 80 and 95% of the dried material, the rest being essentially of α-D-glucopyranosyl - (1? 6) -D-mannitol. This step of chromatography can be carried out discontinuously on a single column of resin or on many columns operating in parallel, but it is more conveniently conducted on the systems of multiple columns branched in curl, operating according to the principle of movable bed simulated . These systems have the advantage of producing better resin yields and continuous operation. In general, to obtain the best yields of the chromatography resins, it is preferred to perform this chromatography at a temperature comprised between 60 and 90 ° C. As already stated above, the fraction excluded at the beginning of the washing cycle, depleted of o-O-glucopyranosyl- (1? 6) -D-sorbitol, is advantageously collected in such amount that it contains an approximately equimolar proportion of aD- glucopyranosyl- (1? 6) -D-mannitol and of aD-glucopyranosyl- (1? 6) -D-sorbitol. The adsorbed fraction, which represents the end of the wash cycle and contains essentially D-glucopyranosyl- (1? 6) -D-sorbitol and a little of aD-glucopyranosyl- (1? 6) -D-mannitol, is then concentrated it is crystallized under conditions known to the person skilled in the art to extract the aD-glucopyranosyl- (1? 6) -D-sorbitol anhydrate for commercialization. The fraction collected at the beginning of the wash cycle and containing in approximately equimolar proportions the a; -D-glucopyranosyl- (1? 6) -D-mannitol and the ot-D-glucopyranosyl- (1-6) -D- sorbitol is then, but preferably only, demineralized on a mixed bed of strong cationic and anionic resins then concentrated, crystallized and dried to provide a commercial powder of palatinitol which is in fact a mixture of approximately equimolar proportions of anhydrous isomaltitol and o / -D-glucopyranosyl- (1? 6) -D-mannitol dihydrate. The present invention is illustrated by the example that follows and that is not limiting, the Applicant has no other purpose than to expose what appears to be one of the best means of employing the method of his invention.

EXAMPLE First stage: It is placed in solution in 36 grams of water, 4 grams of crystallized isomalt as well as 16 milligrams of ammonium molybdate (NH) 6Mo7024, or 0.4 percent by weight with respect to isomaltose, then the pH of this solution is adjusted to 3.5 with the help of hydrochloric acid. This solution is immediately taken at 130 ° C for 15 minutes. After cooling, this solution is demineralized on a mixed bed of strong cationic and anionic resins which provide an epimerized mixture whose resistivity is higher than 2.106 ohms.cm. HPLC chromatography of this epimerized mixture reveals the presence of 35 percent ce-D-glucopyranosyl- (1? 6) -D-mannose and 65 percent isomaltose. The presence of glucose and mannose is also observed, although in a trace state. Second stage: This epimerized mixture was introduced into a hydrogenation reactor in the presence of 5 weight percent sugars, Raney nickel. After having placed the apparatus under a hydrogen pressure of 50 bars which will be maintained throughout the duration of the hydrogenation, its content is heated to a temperature of 125 ° C. The pH of the reaction medium at 8.0 is maintained throughout the course of this hydrogenation with the aid of a sodium bicarbonate solution. The hydrogenation is stopped after 8 hours, after the content of reducing sugars in the reaction medium, measured by the Bertrand method, becomes lower than 0.1 percent. The content of the hydrogenation reactor is then filtered to remove the catalyst then the syrup is demineralized on a mixed bed of resins, as after the first stage. A perfectly clear and colorless syrup is then obtained whose composition by gas chromatographic analysis is tested as follows: isomaltitol: 64.2 percent aD-glucopyranosyl- (1? 6) -D-mannitol: 34.7 percent Third stage In a column of glass with thermostat of double wrapping at 65 ° C, of a height of 2 meters and with an internal diameter of 15 millimeters, 340 cubic centimeters of the resin marketed under the brand name PCR 732 by the PUROLITE Company are introduced. This resin has the following characteristics: skeleton: sulfonated polystyrene crosslinked with divinylbenzene crosslinking rate: 7 percent - granulometry: 180 to 280 microns ionic form for use: Ca ++ It is introduced at the top of this column, 2.5 cubic centimeters of the hydrogenated mixture that was concentrated at 10 percent was then percolated through the resin and pushed with water, at a cost of 200 cubic centimeters per hour. After washing 169 cubic centimeters of water, an impoverished fraction of aD-glucopyranosyl- (1? 6) -D-sorbitol, containing the aD-glucopyranosyl- (1? 6) -D-sorbitol and the aD-glucopyranosyl- (1? 6) -D-mannitol in approximately equimolar proportions and representing 78 cubic centimeters. This fraction containing the palatinitol components, in the dissolved state, shows in the chromatographic analysis in gas phase, a richness of oz-D-glucopyranosyl- (1? 6) -D-mannitol of 49 percent and a richness of o-D-glucopyranosyl- (1? 6) -D-sorbitol 49.5 percent. Immediately following this palatinitol fraction, a fraction of 81 cubic centimeters constituted by a very rich mixture of aD-glucopyranosyl- (1? 6) -D-sorbitol is recovered, whose chromatographic analysis in gas phase reveals a richness of aD-glucopyranosyl - (1? 6) -D-sorbitol 92 percent and 7 percent ce-D-glucopyranosyl- (l? 6) -D-mannitol. This analysis also reveals traces of sorbitol and mannitol. This step is performed 10 times to obtain an adsorbed aD-glucopyranosyl- (1? 6) -D-sorbitol fraction, with an average richness of 91.7 percent and a fraction excluded from a mixture of almost equal parts of ar-D-glucopyranosyl - (1? 6) -D-mannitol and of aD-glucopyranosyl- (1? 6) -D-sorbitol containing 49.5 percent of aD-glucopyranosyl- (1? 6) -D-sorbitol and 49.1 percent of oD -glucopyranosyl- (1? 6) -D-mannitol. The adsorbed chromatographic fraction, rich in GI-D-glucopyranosyl- (1? 6) -D-sorbitol, was concentrated in vacuo to a dry matter of 75 percent. Upon cooling, it allowed crystals of a-D-glucopyranosyl- (1? 6) -D-sorbitol anhydrous to appear. The chromatographic fraction excluded, containing 49.1 percent of aD-glucopyranosyl- (1? 6) -D-sorbitol and 49.5 percent of aD-glucopyranosyl- (1? 6) -D-mannitol was concentrated so as to bring its two components to the state of crystals that are then dried to provide a white, non-hygroscopic palatinitol powder that titrates 5.1 percent moisture.

Claims (4)

1. Process for the manufacture of palatinitol, characterized in that - in a first step, the epimerization of isomaltose is carried out under conditions which make it possible to obtain a mixture of aD-glucopyranosyl- (1? 6) -D-mannose and isomaltose, in a second stage, the catalytic hydrogenation of this mixture is carried out, in a third step, the isomaltitol chromatographic depletion of this hydrogenated mixture is proceeded in order to obtain an approximately equimolecular mixture of α-D-glucopyranosyl- (1-6) - D-sorbitol and of c * -D-glucopyranosyl- (1? 6) -D-mannitol.

2. Process according to claim 1, characterized in that the epimerization is carried out in the presence of a hexavalent molybdenum salt. Method according to one or the other of claims 1 and 2, characterized in that the chromatographic depletion of isomaltitol from the hydrogenated mixture is carried out on cationic resins in the alkaline or alkaline-earth form. 4. Process according to claim 3, characterized in that the cationic resins are used in the form of calcium.