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United States Department of Agriculture

Agricultural Research Service

Title: Breaking Chains: a Comparison of Methods for the Production of Low Viscosity Dextrans and Alternan

item Cote, Gregory
item Willett, Julious
item Payne Wahl, Kathleen

Submitted to: Saccharides Symposium
Publication Type: Abstract Only
Publication Acceptance Date: June 4, 1997
Publication Date: N/A

Technical Abstract: Low-molecular-weight dextrans are used for such clinical applications as blood plasma extenders and starting materials for dextran sulfates. Related low-molecular weight glucans have been proposed as food ingredients. Normally, dextrans are synthesized from sucrose as high- molecular weight polymers, which are unsuitable for many applications. Strategies for producing materials of lower molecular size include acid hydrolysis, enzymolysis, peroxide-catalyzed depolymerization, ultrasonication, gamma-irradiation, and shear degradation. Synthesis in the presence of acceptors (polymerization terminators) is also an option. Each of these methods has its advantages and drawbacks. We will compare some of these methods and their suitability for various end-uses. Since our main interest is the cost-efficient production of low-viscosity alternan and branched dextrans as bulk chemicals, we have focused mainly on physical depolymerization methods. Our results suggest that the most effective method on a laboratory scale is ultrasonication, whereas twin-screw extrusion shows promise for larger- scale production. Properties of materials processed by both methods will be described.

Last Modified: 4/22/2015
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