Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing compound containing saccharide radical
Reexamination Certificate
1998-09-25
2001-09-04
Prats, Francisco (Department: 1651)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing compound containing saccharide radical
C435S096000, C435S098000, C435S099000, C435S100000
Reexamination Certificate
active
06284498
ABSTRACT:
The invention relates to a method of manufacturing a syrup which is rich in maltose. It relates equally to a method of manufacturing a syrup which is rich in maltitol from a maltose-rich syrup obtained by the method according to the present invention.
Methods allowing the production of maltose-rich syrups are already known. Amongst these methods it is possible to quote in particular the one described by HODGE and Coll. in “Cereal Chemistry” No 25, pages 19-30, January 1948, and which contains a stage of precipitation of limit-dextrins by alcohol solutions, and the one described by WOLFROM and THOMPSON in “Methods in carbohydrate chemistry”, 1962, pages 334-335, and which includes a stage of repeated crystallisation of the octaacetate of maltose followed by the crystallisation of the maltose.
Other methods of manufacturing maltose-rich syrups have also been proposed comprising a stage of adsorption on charcoal of the dextrins (U.S. Pat. No. 4.194.623), a stage of chromatography on zeolites or cationic or anionic resins (FR-A-2.510.581), a stage of ultrafiltration of maltose syrups (U.S. Pat. No. 4.429.122), the combined use of several different enzymes, that is to say an &agr;-amylase, a &bgr;-amylase and an isoamylase or a pullulanase (FR-A2.012.831).
This last technique presents, in relation to the preceding ones, numerous advantages. It suffers nevertheless from certain disadvantages, including in particular the one residing in the fact that the saccharifications have to be carried out with very low levels of dry matter, of the order of 20 g/1, in order to obtain a maximum hydrolysis efficiency of the enzymes.
The document FR-A-2.000.580 describes a method of preparing a syrup with a high content of maltitol by hydrogenation of a syrup with a high content of maltose which is obtained by liquefaction of a starch milk with a low content of dry matter to a dextrose equivalent lower than 2, the product thus obtained being saccharified under the action of specific enzymes.
This process is expensive, gives a mediocre yield and gives rise to problems of bacterial contamination and to occurrences of retrogradation of the amylose. In addition, the syrup obtained contains proportions of polymers with a degree of polymerization (DP in the rest of the specification) greater than or equal to 4, which are a nuisance.
More recently, the document U.S. Pat. No. 5.141.859 proposed a method of manufacturing a syrup with a high maltose content, using two successive stages of saccharification. This document advocates in fact a method comprising a first stage of saccharification in the presence of a &bgr;-amylase and a subsequent stage of saccharification in the presence of a maltogenic &agr;-amylase. According to this document, the maltogenic &agr;-amylase is used, after the first stage of saccharification with the &bgr;-amylase, to hydrolyse the oligosaccharides (from DP3 to DP7), and essentially the maltotriose (trisaccharide) into maltose and glucose.
In a surprising and unexpected manner, the applicant company has noted that syrups with a maltose content as high as those described in the document U.S. Pat. No. 5.141.859 could be obtained by saccharifying a starch milk which had first been liquefied by means of a maltogenic &agr;-amylase, then in continuing this saccharification by means of a &bgr;-amylase.
Thus, contrary to the teaching of the document U.S. Pat. No. A5.141.859, the applicant company has revealed that the maltogenic &agr;-amylase was capable of hydrolysing the polysaccharides of a liquefied starch milk, and that this enzyme could thus be used directly on the latter without first of all going through a stage of saccharification with the &bgr;-amylase.
This discovery is all the more surprising since it would have been possible to think that, after the saccharification with the aid of a maltogenic &agr;-amylase, continuing the saccharification with the &bgr;-amylase would not have any effect on the high maltose content of the syrup obtained. In fact, maltogenic &agr;-amylase is known, on the one hand, for releasing the &agr;-maltose and, on the other hand, for being capable of hydrolysing, unlike the &bgr;-amylase, the maltotriose into maltose and glucose. It could therefore be expected that the use of the maltogenic &agr;-amylase would, on its own, have made it possible to obtain a hydrolysate with a very high maltose content and that the subsequent addition of &bgr;-amylase was superfluous. The applicant company established, against all expectation, that such was not the case.
The invention thus proposes a method of manufacturing a maltose-rich syrup, comprising the successive stages, consisting of:
(a) carrying out a liquefaction of a starch milk;
(b) carrying out a saccharification of the liquefied starch milk in the presence of a maltogenic &agr;-amylase;
(c) continuing the saccharification of the liquefied starch milk in the presence of a &bgr;-amylase and at least one debranching enzyme chosen from the group consisting of pullulanases and isoamylases with a view to obtaining a syrup which is rich in maltose.
The invention proposes in addition a method of manufacturing a maltose-rich syrup, comprising the successive stages, consisting of:
(a) carrying out a liquefaction of the starch milk;
(b) carrying out a saccharification of the liquefied starch milk in the presence of a maltogenic &agr;-amylase and at least one debranching enzyme chosen from the group consisting of pullulanases and isoamylases with a view to obtaining a syrup which is rich in maltose.
If necessary, stage (b) of saccharification of the liquefied starch milk can be continued in the presence of a &bgr;-amylase.
In pursuing its research efforts into the characteristics of maltogenic &agr;-amylase, the applicant company has, in addition, established that if the use of maltogenic &agr;-amylase made it possible, effectively and advantageously, to lower the proportion of maltotriose by hydrolysis of the latter into maltose and glucose, it presented the major disadvantage of generating significant quantities of glucose, and possibly of sorbitol in the case of hydrogenation of the hydrolysates. Indeed, to the residual glucose obtained after saccharification of the liquefied starch milk is added a significant proportion of glucose stemming from the hydrolysis of the maltotriose by the maltogenic &agr;-amylase.
These significant quantities of glucose, and thus of sorbitol after hydrogenation, make the crystallisation of the maltitol more difficult and lead to a drop in the richness of the crystals, making them poorly suited to certain applications such as the manufacture of chocolate, for example.
In addition, the persistence of free glucose or sorbitol in the maltose or maltitol syrups causes other disadvantages such as a drop in the viscosity and the relative humidity balance of the products into which they are incorporated as sugar substitutes.
Conscious that there exists a growing interest in products with a very high maltose content, the applicant company has conducted extensive research with the aim of perfecting an economic and extremely reliable method making it possible to obtain such products.
In a manner which was extremely simple and particularly effective in view of everything previously proposed, the applicant company established that syrups with a very high maltose content could easily be manufactured by submitting a maltose syrup, obtained in accordance with the method according to the invention, to a supplementary stage of transformation of the glucose with the aid in particular of a glucose oxidase, of a raising agent or of an oxidising bacterium.
Despite its simplicity, this supplementary stage of the method according to the invention makes it surprisingly possible to manufacture, with an excellent yield, a syrup with a very high maltose content without having recourse to an expensive separation stage, using chromatography for example, such as is the case with documents EP-A-185.595 and U.S. Pat. No. 5,141,859.
The first stage of the method according to the invention is itself known. It consist
Delobeau Didier
Fouache Catherine
Quenon Bruno
Henderson & Sturm LLP
Prats Francisco
Roquette Freres
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