Branched α-glucan, α-glucosyltransferase which forms the glucan, their preparation and uses

Patent metadata

Field	Value
Publication number	US-9528134-B2
Application number	US-201514734607-A
Country	US
Kind code	B2
Filing date	Jun 9, 2015
Priority date	Apr 26, 2007
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

The present invention has objects to provide a glucan useful as water-soluble dietary fiber, its preparation and uses. The present invention solves the above objects by providing a branched α-glucan, which is constructed by glucose molecules and characterized by methylation analysis as follows:
(1) Ratio of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol to 2,3,4-trimethyl-1,5,6-triacetyl-glucitol is in the range of 1:0.6 to 1:4; (2) Total content of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol and 2,3,4-trimethyl-1,5,6-triacetyl-glucitol is 60% or higher in the partially methylated glucitol acetates; (3) Content of 2,4,6-trimethyl-1,3,5-triacetyl-glucitol is 0.5% or higher but less than 10% in the partially methylated glucitol acetates; and (4) Content of 2,4-dimethyl-1,3,5,6-tetraacetyl-glucitol is 0.5% or higher in the partially methylated glucitol acetates; a novel α-glucosyltransferase which forms the branched α-glucan, processes for producing them, and their uses.

First claim

The invention claimed is:

1. A process for producing a saccharide composition comprising branched α-glucan, comprising the steps of:
allowing an α-glucosyltransferase and cyclomaltodextrin glucanotransferase to act on maltose and/or α-1,4 glucan having a glucose polymerization degree of 3 or higher; and
collecting the formed saccharide composition comprising branched α-glucan;
said saccharide composition is characterized in that it forms isomaltose in an amount of 25% (w/w) or higher but 50% (w/w) or lower, on a dry solid basis, when the saccharide composition is digested by isomaltodextranase (EC 3.2.1.94).

2. The process of claim 1 , wherein said saccharide composition has the following characteristics upon methylation analysis:
(1) Ratio of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol to 2,3,4-trimethyl-1,5,6-triacetyl-glucitol, which indicates the ratio of glucose residues with α-1,4 linkages to glucose residues with α-1,6 linkages, is in the range of 1:0.6 to 1:4; and
(2) Total content of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol and 2,3,4-trimethyl-1,5,6-triacetyl-glucitol, which indicates that the total content of glucose residues with α-1,4 linkages and glucose residues with α-1,6 linkages, is 60% or higher in the partially methylated glucitol acetates.

3. The process of claim 2 , wherein said saccharide composition has the following characteristics upon methylation analysis:
(3) Content of 2,4,6-trimethyl-1,3,5-triacetyl-glucitol, which indicates that the content of glucose residues with α-1,3 linkage, is 0.5% or higher but less than 10% in the partially methylated glucitol acetates; and
(4) Content of 2,4-dimethyl-1,3,5,6-tetraacetyl-glucitol, which indicates that the content of glucose residues with both α-1,3 and α-1,6 linkages, is 0.5% or higher in the partially methylated glucitol acetates.

4. The process of claim 1 , wherein said saccharide composition is characterized in that the content of water-soluble dietary fiber of the saccharide composition, obtained by applying a high performance liquid chromatography method is 40% (w/w) or higher.

5. The process of claim 1 , wherein said α-glucosyltransferase is an enzyme having the activity of forming a saccharide composition comprising branched α-glucan from a substrate of maltose or α-1,4 glucan having a glucose polymerization degree of 3 or higher;
wherein said saccharide composition having the following characteristics upon methylation analysis:
(1) Ratio of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol to 2,3,4-trimethyl-1,5,6-triacetyl-glucitol, which indicates the ratio of glucose residues with α-1,4 linkages to glucose residues with α-1,6 linkages, is in the range of 1:0.6 to 1:4;
(2) Total content of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol and 2,3,4-trimethyl-1,5,6-triacetyl-glucitol, which indicates that the total content of glucose residues with α-1,4 linkages and glucose residues with α-1,6 linkages, is 60% or higher in the partially methylated glucitol acetates;
(3) Content of 2,4,6-trimethyl-1,3,5-triacetyl-glucitol, which indicates that the content of glucose residues with α-1,3 linkage, is 0.5% or higher but less than 10% in the partially methylated glucitol acetates; and
(4) Content of 2,4-dimethyl-1,3,5,6-tetraacetyl-glucitol, which indicates that the content of glucose residues with both α-1,3 and α-1,6 linkages, is 0.5% or higher in the partially methylated glucitol acetates.

6. The process of claim 1 , wherein said α-glucosyltransferase has the following physicochemical properties:
(1) Molecular weight
90,000±10,000 daltons on SDS-polyacrylamide gel electrophoresis;
(2) Optimum temperature
50 to 55° C. when reacted at pH 6.0 for 30 min;
(3) Optimum pH
pH 5.0 to 6.3 when reacted at 40° C. for 30 min;
(4) Thermal stability
Stable up to the temperature of 40° C. when incubated at pH 6.0 for 60 min; and
(5) pH Stability

Stable at least in the range of pH 4.0 to 8.0 when incubated at 4° C. for 24 hours.

7. The process of claim 4 , wherein the high performance liquid chromatography method is Enzyme-HPLC.

Assignees

• Hayashibara Co
• Hayashibara Co

Inventors

• Watanabe Hikaru
• Yamamoto Takuo
• Nishimoto Tomoyuki
• Tsusaki Keiji
• Oku Kazuyuki
• Chaen Hiroto
• Fukuda Shigeharu

Classifications

• A61P3/10

  for hyperglycaemia, e.g. antidiabetics · CPC title

• A61P3/06

  Antihyperlipidemics · CPC title

• A61P9/10

  for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis · CPC title

• A61P3/04

  Anorexiants; Antiobesity agents · CPC title

• A61P1/14

  Prodigestives, e.g. acids, enzymes, appetite stimulants, antidyspeptics, tonics, antiflatulents · CPC title