阅读说明：本技术 富含麦芽糖醇的产物 (Maltitol enriched product ) 是由 T.富尔兰 L.纳塔罗尼 P.托罗梅利 于 2013-01-24 设计创作，主要内容包括：本发明涉及富含麦芽糖醇的产物和用于制备富含麦芽糖醇的糖浆的方法。所述方法包括如下连续步骤：在存在α-淀粉酶、β-淀粉酶以及选自支链淀粉酶、异淀粉酶和它们的混合物的脱支酶(优选支链淀粉酶)的情况下进行淀粉乳的液化以及所述液化淀粉乳的糖化,并且再添加麦芽糖α-淀粉酶和/或异淀粉酶以获得含麦芽糖的糖浆,所述含麦芽糖的糖浆包含基于干物质计至少85％的麦芽糖和基于干物质计小于1.5％的葡萄糖,优选地基于干物质计小于1％的葡萄糖,然后对所述含麦芽糖的糖浆进行分子筛分以获得级分(A),所述级分(A)包含基于级分(A)的干物质计至少95％的麦芽糖,并且还催化氢化级分(A)以获得富含麦芽糖醇的液体产物(B)。(The present invention relates to maltitol enriched products and a process for the preparation of maltitol enriched syrups. The method comprises the following successive steps: liquefaction of a starch milk and saccharification of the liquefied starch milk is carried out in the presence of an alpha-amylase, a beta-amylase and a debranching enzyme selected from pullulanase, isoamylase and mixtures thereof, preferably pullulanase, and further adding a maltose alpha-amylase and/or isoamylase to obtain a maltose containing syrup, the maltose containing syrup comprises at least 85% maltose based on dry matter and less than 1.5% glucose based on dry matter, preferably less than 1% glucose based on dry matter, then subjecting the maltose containing syrup to molecular sieving to obtain fraction (A) comprising at least 95% maltose based on dry matter of fraction (A), and also catalytically hydrogenating fraction (a) to obtain a liquid product (B) enriched in maltitol.)

1. A process for the preparation of maltitol-containing syrups, comprising the successive steps of:

a) carrying out liquefaction of the starch milk, carrying out controlled partial inhibition of alpha-amylase once the liquefaction step is finished,

b) saccharifying the liquefied starch milk in the presence of an alpha-amylase, a beta-amylase, and a debranching enzyme selected from the group consisting of pullulanase, isoamylase, and mixtures thereof,

c) further adding maltose alpha-amylase and/or isoamylase to obtain a maltose containing syrup comprising at least 85% maltose on dry matter basis, less than 1.5% glucose on dry matter basis and less than 10% DP3+ on dry matter basis, said DP3+ being an oligosaccharide with a degree of polymerization of 3 or more, optionally followed by demineralization of the maltose containing syrup,

d) subjecting the maltose containing syrup to molecular sieving to obtain fraction (A) comprising at least 95% maltose based on dry matter of fraction (A),

e) catalytically hydrogenating fraction (A) to obtain a liquid product (B) enriched in maltitol, wherein in step B) the saccharification takes place in the presence of a residual amount of alpha-amylase applied in the liquefaction of step a), preferably in the presence of a residual activity of 1 to 4% of the total amount of alpha-amylase applied in the liquefaction,

wherein additional alpha-amylase is added after step c), and wherein the alpha-amylase is added when about 70 to 85% of the total saccharification time has elapsed.

2. The method of claim 1, wherein the molecular sieving of step d) is a chromatographic separation.

3. The method according to any one of claims 1 to 2, wherein in step b) the ratio of β -amylase to debranching enzyme is from 1:1 to 1: 4.

4. the process according to any one of claims 1 to 3, wherein in step b) the debranching enzyme is a pullulanase.

5. The process according to any one of claims 1 to 4, wherein in step a), the liquefaction is carried out until the D.E. is not higher than 6.

6. The process according to any one of claims 1 to 5, wherein in step c) the addition of the maltogenic alpha-amylase and/or isoamylase is carried out at a time elapsed of about 20 to 50% of the total saccharification time.

Technical Field

The present invention relates to a process for preparing a high purity liquid maltitol product.

Background

Methods for making it possible to prepare syrups rich in maltitol are well known.

US 5,873,943 provides an economically convenient process for the manufacture of crystalline maltitol. The process uses a product with a maltose purity of 81 to 90% as a starting material. The syrup was hydrogenated and then subjected to chromatographic separation to obtain an aqueous solution of maltitol having a maltitol purity of 94 to 99.9%. The aqueous solution is further crystallized in the presence of a seed crystal.

EP1656388 relates to a process for preparing a maltitol enriched product and which separates a maltose syrup chromatographically and then hydrogenates it to a maltitol enriched liquid product and optionally coagulates or crystallizes the maltitol. Liquid, solid and crystalline maltitol of different purity can be obtained by a single process.

WO 2008/029033 relates to a process for obtaining a syrup with a high maltitol content, and the invention is particularly suitable for use in the field of the agro-food industry.

There remains a need for a method of providing syrups rich in maltitol as well as low sorbitol and low maltotriol.

Disclosure of Invention

The present invention relates to a process for the preparation of maltitol-containing syrups, said process comprising the following successive steps

a) The liquefaction of the starch milk is carried out,

b) saccharifying a liquefied starch milk in the presence of an alpha-amylase, a beta-amylase, and a debranching enzyme selected from the group consisting of pullulanase, isoamylase, and mixtures thereof,

c) further adding maltose alpha-amylase and/or isoamylase to obtain maltose containing syrup comprising at least 85% maltose on dry matter basis and less than 1.5% glucose on dry matter basis, optionally, then demineralizing the maltose containing syrup,

d) subjecting the maltose containing syrup to molecular sieving to obtain fraction (A) comprising at least 95% maltose based on dry matter of fraction (A),

e) catalytically hydrogenating fraction (a) to obtain a liquid product (B) enriched in maltitol, wherein in step B) the saccharification is performed in the presence of residual amount of alpha-amylase applied in the liquefaction of step a), preferably in the presence of residual activity of 1 to 4% of the total amount of alpha-amylase applied in the liquefaction.

The invention also relates to the use of a maltose containing syrup comprising at least 85% maltose on a dry matter basis and less than 1.5% glucose on a dry matter basis and less than 10% DP3 on a dry matter basis to reduce the amount of catalyst by at least 5% in the hydrogenation step of the maltose containing syrup.

Detailed Description

The present invention relates to a process for the preparation of maltitol-containing syrups, said process comprising the following successive steps

a) The liquefaction of the starch milk is carried out,

b) saccharifying a liquefied starch milk in the presence of an alpha-amylase, a beta-amylase, and a debranching enzyme selected from the group consisting of pullulanase, isoamylase, and mixtures thereof, preferably pullulanase,

c) and further adding maltose alpha-amylase and/or isoamylase to obtain maltose-containing syrup,

comprising at least 85% maltose on a dry matter basis and less than 1.5% glucose on a dry matter basis, optionally followed by demineralization of the maltose containing syrup

d) Subjecting the maltose containing syrup to molecular sieving to obtain fraction (A) comprising at least 95% maltose based on dry matter of fraction (A),

e) catalytically hydrogenating fraction (A) to obtain a liquid product (B) enriched in maltitol,

wherein in step b) the saccharification is performed in the presence of a residual amount of alpha-amylase applied in the liquefaction of step a), preferably in the presence of a residual activity of 1% to 4% of the total amount of alpha-amylase applied in the liquefaction.

The liquefaction is carried out in the presence of an alpha-amylase.

Liquefaction and saccharification of starch can be carried out in a number of ways, but the present invention demonstrates that combining liquefaction with a specific saccharification step enables the following maltose syrups to be obtained: it comprises at least 85% maltose (═ DP2), or at least 87%, at least 90% maltose on a dry matter basis, and less than 1.5% glucose (═ DP1), preferably less than 1% glucose on a dry matter basis, and preferably comprises less than 10% DP3, more preferably comprises less than 10% oligosaccharides with a degree of polymerization of 3 or greater (═ DP3 +).

Starch of any plant origin is liquefied. For example, it may be derived from wheat, corn or potato.

The liquefaction is considered to be a controlled hydrolysis of the starch milk, preferably in the presence of an enzyme (e.g. alpha-amylase) to obtain a liquefied starch milk with a low degree of conversion. Thus, the conditions of temperature, pH, enzyme (type and concentration) are chosen in the following way: said manner makes it possible to obtain a DE (═ dextrose equivalent) of not more than 6, preferably from 4 to 5.

Preferably, the liquefaction is carried out in three steps: the first step involves heating the starch milk at a temperature in the range of 105 to 108 ℃ and in the presence of a thermostable alpha-amylase for several minutes, typically from 8 to 15 minutes, no longer than 20 minutes. The second step comprises heating the starch milk to treat for several minutes, such as 5 to 8 minutes, but not more than 20 minutes, at a temperature in the range of 140 to 160 ℃, preferably in the range of 145 to 155 ℃. After cooling to about 95 to 100 ℃, a second small amount of alpha-amylase is added and liquefaction is continued for an additional 30 to 50 minutes, adjusted to obtain a starch slurry with a d.e. of 4 to 6, preferably 4 to 5.

The liquefaction according to the invention makes it possible to obtain d.e. of 4 to 6, preferably 4 to 5, wherein the composition of the oligosaccharides (DPn) is previously fine-tuned for subsequent saccharification.

Once the liquefaction step is finished, a controlled inhibition is performed such that only a partial inhibition of the alpha-amylase is performed and residual alpha-amylase remains for the subsequent saccharification step. Preferably, the partial inhibition is carried out at a pH of 3.5 to 4 and at a temperature of not higher than 100 ℃. Preferably, the partial inhibition occurs over a period of 1 to 10 minutes. The residual (residual activity) alpha-amylase is also used in the subsequent saccharification step. Preferably, the residual alpha-amylase corresponds to 5 to 15% of the total amount added in the second feed of liquefaction. Finally, the residual alpha-amylase corresponds to 7% to 12% of the total amount added in the second feed of liquefaction.

This corresponds to a residual activity of 1 to 4%, preferably 1.4 to 3%, of the total amount of alpha-amylase compared to the actual total amount of alpha-amylase added during liquefaction (1 + second dosed amount).

Preferably, the saccharification of the liquefied starch milk is performed in the presence of alpha-amylase and beta-amylase and pullulanase as debranching enzyme, wherein the saccharification is performed in the presence of a residual amount of alpha-amylase applied in the liquefaction of step a), in the presence of a residual activity of 1% to 4% of the total amount of alpha-amylase applied in the liquefaction, or in the presence of a residual activity of 1.4% to 3%.

Saccharification is then continued by the addition of a beta-amylase and a debranching enzyme selected from the group consisting of pullulanase, isoamylase, and mixtures thereof. Preferably pullulanase is added. The addition of a debranching enzyme makes it possible to hydrolyze the 1, 6-linkage and thereby reduce the amount of highly branched oligosaccharides. Preferably, the ratio of beta-amylase to debranching enzyme is from 1:1 to 1: 4. Preferably, the ratio of β -amylase to pullulanase is from 1:1 to 1: 4. Ratios from 1:1 to 1:5 or even as high as 1:10 are encompassed by the present invention. Preferably, in applying pullulanase as debranching enzyme, the ratio of β -amylase to pullulanase is from 1:2 to 1:4, and preferably a higher end ratio of from 1:3 to 1:4 is applied.

The maltogenic alpha-amylase and/or isoamylase is added to the thus treated starch milk at about 20 to 50% of the time of the total saccharification, preferably at about 20 to 35% of the time, preferably at about 25 to 30% of the time of the total saccharification. Maltose alpha-amylase is an exo alpha-amylase, which is responsible for the exo-hydrolysis of 1, 4-alpha-glycosidic bonds. Isoamylases are debranching enzymes that hydrolyze 1, 6-linkages and reduce the amount of reverse products.

In a typical process, the total saccharification time is about 16 to 30 hours, preferably from 20 to 24 hours, and the maltogenic alpha-amylase and/or isoamylase are added after 7 to 8 hours saccharification time.

Thereby continuing the saccharification until a maltose enriched syrup is obtained comprising at least 85% maltose based on dry matter and less than 1.5% glucose based on dry matter, preferably less than 1% glucose based on dry matter.

More preferably, the saccharification is carried out to obtain a maltose enriched syrup such that it comprises at least 85% maltose on a dry matter basis, or at least 87% maltose on a dry matter basis, at least 90% maltose and less than 1.5% glucose on a dry matter basis, preferably less than 1% glucose and less than 10% DP3 on a dry matter basis, or less than 10% polymer on a dry matter basis, with a degree of polymerization of 3 or more (═ DP3+), preferably less than 5% DP3 +. Still more preferably, polymers with a degree of polymerisation above 3 are negligible and the amount of polymers with a degree of polymerisation of 3 is below 5%, more preferably below 3%, most preferably below 1% based on dry matter of the syrup.

Finally, more towards the end of the saccharification step, additional alpha-amylase is added. This particular low level may further improve subsequent downstream processes. The alpha-amylase is added at about 70 to 85% of the total saccharification time, preferably at about 80 to 83% of the total saccharification time. This may correspond to about 4 hours before the end of the saccharification process.

The process of the invention allows to obtain products with a very high content (═ at least 85%, 87%, 90%) of maltose, whereas the content of glucose is lower than 1.5%, with a low amount of DP3, and with a reduced amount of long chain oligosaccharides present therein. The composition of DPn differs from the composition normally obtained after liquefaction and saccharification. In particular, the use of residual alpha-amylase in the subsequent saccharification step and the further addition of alpha-amylase towards the end of saccharification contribute to the change in the composition of the DPn (oligosaccharide) fraction. The amount of higher oligosaccharides (longer chains) decreases.

The saccharified syrup thus obtained can be purified according to well-known demineralization methods, for example by applying ion-exchange resins. Alternatively, the saccharified syrup may be filtered on a precoated filter or by microfiltration on a membrane, followed by demineralization.

So far, high maltose syrups with low glucose amounts (up to 80%) and very high maltose (up to 90%) with significant residual glucose amounts (5 to 7%) have been obtained. The present invention has demonstrated that by applying liquefaction according to the present method in combination with a saccharification step, which is claimed herein, it is surprisingly possible to obtain maltose syrups with very high maltose content (at least 85%, at least 87%, at least 90%) and low glucose content (less than 1.5%, less than 1%). And the final DP3 content is also low, less than 10%, preferably less than 5%. Furthermore, the DPn fractions starting with DP4 have a significantly different composition, resulting in a reduced amount of long chain oligosaccharides. This altered composition makes the final product of the invention more stable and it is a better precursor for the production of maltitol by hydrogenation. Or the time of the hydrogenation step can be significantly shortened or the catalyst is less dependent under the same hydrogenation conditions.

The maltose containing syrup obtained after saccharification is subjected to a molecular sieving step. The molecular sieving may be an on-membrane separation stage or a chromatographic separation stage. In the process according to the invention, an on-membrane nanofiltration stage may be employed in the on-membrane separation stage. Membranes with different pore sizes are commercially available and are described in many patent applications.

The chromatographic separation is carried out discontinuously or continuously (simulated moving bed) on an adsorbent, for example an ionic resin or a zeolite, preferably with cationic resin applied. Preferably, the cationic resin is impregnated with alkali or alkaline earth metal ions, more preferably with the aid of sodium ions.

By applying the same or similar conditions in the chromatographic separation, which relate to column design, resin type, feed temperature, flow rate, dry matter of the feed, etc., the yield of the maltose rich fraction is increased by at least 5%, preferably by at least 10%, as used for the chromatographic separation of the product in EP 1656388. The yield was calculated as the amount of maltose rich fraction multiplied by the dry matter of the fraction and divided by the amount of feed multiplied by the dry matter of the feed, then each term was multiplied by 100 to express as a percentage.

This means that by obtaining maltose containing syrups with a very high maltose content (at least 85%, 87%, 90%) and a low glucose content (less than 1.5%, less than 1%) and finally also a DP3 content of less than 10%, preferably less than 5%, the yield of the subsequent chromatographic separation is increased by at least 5%, preferably at least 10%.

The invention also relates to the use of a maltose containing syrup comprising at least 85% maltose, or at least 87%, at least 90% maltose on a dry matter basis, and less than 1.5% glucose on a dry matter basis and less than 10% DP3 on a dry matter basis, preferably less than 1% glucose on a dry matter basis, to increase the yield of chromatographic separations by at least 5%, preferably at least 10%.

The present invention relates to a method for increasing the chromatographic separation yield of a maltose containing syrup comprising at least 85% maltose, or at least 87%, at least 90% maltose on a dry matter basis and less than 1.5% glucose on a dry matter basis and less than 10% DP3 on a dry matter basis, preferably less than 1% glucose on a dry matter basis by applying the maltose containing syrup.

The fraction (a) (═ maltose-rich fraction) thus obtained, which comprises at least 95%, preferably at least 96%, preferably at least 97%, more preferably at least 98% maltose based on dry matter of fraction (a), is subjected to hydrogenation in the presence of a hydrogenation catalyst. A raney nickel based catalyst is preferably used as the hydrogenation catalyst.

Any hydrogenation conditions may be suitable as long as decomposition of maltose does not occur. The hydrogenation step is generally carried out under a hydrogen pressure of at least 10 bar, preferably between at least 30 and 200 bar, and at a temperature of 90 to 150 ℃, so that the hydrogenation is continued until the adsorption of hydrogen is stopped.

The syrup supplied (═ fraction (a)) can be used at least 50% dry matter, with the addition of an active nickel catalyst and hydrogenation at temperatures up to 135 ℃ and hydrogen pressures of at least 40 bar. By applying fraction (a) comprising at least 95% maltose and obtained by the process of the invention, the amount of active nickel catalyst in the hydrogenation step can be reduced by at least 5%, preferably by at least 10%. Usually (see EP 1656388) the active nickel catalyst is added in an amount of 4% compared to the dry matter of the feed syrup. In the present invention, the active nickel catalyst is added in an amount of 3.6% compared to the dry matter of the feed syrup (a). Preferably, the change in the composition of the DPn (oligosaccharide) fraction has a favourable effect on the hydrogenation.

The present invention relates to the use of a maltose containing syrup comprising at least 85% maltose, or at least 87%, at least 90% maltose on a dry matter basis, and less than 1.5% glucose on a dry matter basis and less than 10% DP3 on a dry matter basis, preferably less than 1% glucose on a dry matter basis, to reduce the amount of catalyst (preferably active nickel) in the hydrogenation step by at least 5%, preferably at least 10%.

The present invention relates to a method for reducing the amount of catalyst, preferably an active nickel catalyst, in the hydrogenation of maltose containing syrups comprising at least 85% maltose or at least 87%, at least 90% maltose on a dry matter basis and less than 1.5% glucose on a dry matter basis and less than 10% DP3 on a dry matter basis, preferably less than 1% glucose on a dry matter basis by applying a maltose containing syrup.

After the adsorption of hydrogen is completed, such as after about 3 hours of hydrogenation, the hydrogenation catalyst (═ active nickel catalyst) is removed from the resulting liquid maltitol product (B). The syrup may also be decolorized and/or deionized by activated carbon or ion exchange resins and/or purification resins (polisherein).

The invention also relates to a maltitol-containing syrup comprising at least 95% maltitol, preferably at least 96%, more preferably at least 97%, on a dry matter basis, and less than 1.2% sorbitol on a dry matter basis, and having a dry matter content of 50-75%, preferably 55-70%, and which is obtained by the process of the invention. Preferably, the maltitol-containing syrup comprises less than 1.1%, less than 1.0% sorbitol. It also relates to a syrup comprising maltitol, which also comprises less than 10% hydrogenated DP3 on a dry matter basis.

The syrup can be used in food applications or industrial applications, or as a precursor for solidification or crystallization of maltitol or as a feed in chromatographic purification.

The invention is illustrated below by way of the following examples.

Examples of the invention

Example 1

Liquefaction

Starch slurry with a dry matter content between 27-35% ds (as dry matter) was liquefied after pH adjustment to 5.8(± 1) and by feeding 0.08-0.1% alpha-amylase (Spezyme, Genencor) at 108 ℃ using a jet cooker. After 8-15 minutes, the gelatinization temperature was reduced to 100 ℃ by atmospheric flash, and the slurry was sent to a second jet at 152 ℃. After 5-8 minutes of gelatinization, the slurry was cooled to 100 ℃ and a second dose (0.025%) of the same alpha-amylase was added, adjusted to reach 4-6DE (target 4.5).

After 30-50 minutes of reaction at 100 ℃ on a stirred column, the pH of the liquefact is adjusted to 3-4 (target 3.5-4) and kept at 100 ℃ for up to 10 minutes to inhibit a portion of the alpha-amylase. After this treatment, 7 to 10% of the alpha-amylase added as a second dosing amount was maintained.

Example 2

Saccharification formulation 1

The product of example 1 was used. Saccharification was started at pH 4.8-5.0 in the presence of residual alpha-amylase and 0.1% beta-amylase (optimut BBA, Genencor) and 0.4% pullulanase (Promozyme D2, Novozyme). After 7 to 8 hours of reaction, 0.02% of maltose alpha-amylase (Maltogenase, Novozyme) was added.

At least 4 hours before emptying the saccharification tank (saccharoifier), 0.1-0.2% of alpha-amylase (liqozyme X, Novozyme) was added. After a total saccharification time of 24-30 hours, the following composition is reached: glucose < 1%, maltose (═ DP2) 85-87%, DP3(═ oligosaccharide with a degree of polymerization of 3) 7-10%, DP4+ (oligosaccharide with a degree of polymerization of 4 and greater) < 5%.

Purification was performed as for purification to obtain a conventional glucose syrup.

Example 3

Saccharification formulation 2

The product of example 1 was used. Saccharification was started at pH 4.8-5.0 in the presence of residual alpha-amylase, 0.1% beta-amylase (optimut BBA, Genencor), 0.4% pullulanase (Promozyme D2, Novozyme), and 0.1% isoamylase. After 7 to 8 hours of reaction, 0.1% of maltose alpha-amylase (Maltogenase, Novozyme) was added.

At least 4 hours before emptying the saccharification tank, 0.1-0.2% alpha-amylase (Liquozyme X, Novozyme) is added. After a total saccharification time of 24-30 hours, the following composition is reached: glucose < 1%, maltose (═ DP2) 87-90%, and DP3 from 4 to 6%.

Example 4

Chromatographic separation

The product (from formulation 1) with the composition (DP 1: < 1.0% (-0.9%); DP 2: 87% (-86.9%); DP 3: 7.5% and DP4+ <5(— 4.7%)) was concentrated to 60% dry matter.

The concentrated product was applied at 75 ℃ on a chromatographic apparatus (ISMB) with a ion exchange resin Dianion UBK550 in the sodium salt form to obtain a fraction rich in maltose. The product had the following composition (DP 1: < 1.0%; DP 2: 96-98%; DP 3: < 2%; DP4< 1).

HPLC analysis (Bio-Rad Aminex HPX-87, cation exchange column calcium salt type, column temperature: 80 deg.C, eluent flow rate: 0.6 ml/min, column pressure limit: 1200psi, sample volume: 20 μ L, pressure control limit about 200psi above normal working column pressure, eluent pressure degassed Milli-Q purified water, detector differential refractometer)

TABLE 1

The yield of maltose-rich product was 81.2% (total weight of product% d.s. multidot.100/total weight of feed% d.s.).

Comparative example 4 chromatographic separation-see EP 1656388

The product having the composition (DP 1: 1.5%; DP 2: 80.0%; DP 3: 12.5% and DP4 +: 6%) was concentrated to 60% dry matter as obtained in EP 1656388.

The concentrated product was applied at 75 ℃ on a chromatographic apparatus (ISMB) with a ion exchange resin Dianion UBK550 in the sodium salt form to obtain a fraction rich in maltose. The product had the following composition (DP 1: 1.1%; DP 2: 96%; DP 3: 1.7%; DP4 +: 1.2%).

More details are shown in Table 2

TABLE 2

³Results expressed in hourly and m resin

The yield of maltose-rich product was 70.8% (total weight of product% d.s. multidot.100/total weight of feed% d.s.).

Example 5

Hydrogenation

21.6Kg (52% dry matter) of a maltose rich fraction with the composition (DP 1: < 1.0%; DP 2: 96-98%; DP 3: < 2%; DP4<1) was added to a stainless steel hydrogenation reactor. The active nickel catalyst was added in an amount of 3.6% compared to the dry matter of the maltose rich fraction, the suspension was stirred vigorously and heated up to 135 ℃ under a hydrogen pressure of 43 bar. After 180 minutes hydrogenation, the suspension was cooled to 90 ℃ and the catalyst was removed by settling and filtration. Aqueous solutions at a temperature of 40 ℃ were ion exchanged and purified on cationic and anionic resins and carbon particles.

The product obtained had the following composition (HPLC analysis: Bio-Rad Aminex HPX-87, cation exchange column calcium salt type, column temperature: 80 ℃, eluent flow: 0.6 ml/min, column pressure limit: 1200psi, injection volume: 20. mu.L, pressure control limit about 200psi above normal working column pressure, eluent: pressure degassed Milli-Q purified water, detector: differential refractometer)

Comparative example 5 hydrogenation-see EP1656388

21.6Kg (52% dry matter) of a maltose rich fraction having the composition (DP 1: 1.1%; DP: 96%; DP 3: 1.7%; DP4 +: 1.2%) was fed to a stainless steel hydrogenation reactor. The active nickel catalyst was added in an amount of 4% compared to the dry matter of the maltose rich fraction, the suspension was stirred vigorously and heated up to 135 ℃ under a hydrogen pressure of 43 bar. After 180 minutes hydrogenation, the suspension was cooled to 90 ℃ and the catalyst was removed by settling and filtration. Aqueous solutions at a temperature of 40 ℃ were ion exchanged and purified on cationic and anionic resins and carbon particles. The product obtained had the following composition (HPLC analysis: Bio-Rad Aminex HPX-87, cation exchange column calcium salt type, column temperature: 80 ℃, eluent flow: 0.6 ml/min, column pressure limit: 1200psi, injection volume: 20. mu.L, pressure control limit about 200psi above normal working column pressure, eluent: pressure degassed Milli-Q purified water, detector: differential refractometer)