| 摘要 |
PURPOSE:To obtain galactomannan capable of forming an aqueous solution of excellent clarity, by contacting a galactomannan with an alkali metal hydroxide in a medium comprising water or a mixture of water with a hydophilic organic solvent, and neutralizing the product. CONSTITUTION:Galactomannan is contacted with an alkali metal hydroxide (e.g., sodium hydroxide) in a medium comprising water or a mixture of water with a hydrophilic organic solvent (e.g., methanol). The amount of the alkali metal hydroxide added is preferably at least 0.1mol per anhydrosugar unit of galactomannan. Further, it is desirable to effect the contacting at a low temperature for a long time from the viewpoint of its thickening property, and it is further desirable to effect it in an atmosphere of an inert gas such as nitrogen or carbon dioxide gas. This exerts an effect of retaining the thickening property of the product. The product is then neutralized with neutralizing agent (e.g., hydochloric or sulfuric acid) to obtain the desired galactomannan.
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