ARS | Publication request: CHARACTERIZATION OF A NOVEL MODIFIED ALTERNAN

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 14, 2003
Publication Date: July 1, 2003
Citation: Leathers, T.D., Nunnally, M.S., Ahlgren, J.A., Cote, G.L. 2003. Characterization of a novel modified alternan. Carbohydrate Polymers. 54:107-113.

Interpretive Summary: Domestic replacements are needed for certain imported commodities, particularly to improve the U.S. balance of trade. At the same time, new value-added markets are needed for American farmers. Gum arabic is important in food processing and has other industrial applications. The U.S. imports millions of pounds of gum arabic each year. This represents a market of tens of millions of dollars annually, a significant fraction of the U.S. gum market. Imported gum arabic is available only at unreliable supply, quality, and price. Microbial gums are potential substitutes for gum arabic, but require expensive processing to simulate some of the important functional properties of gum arabic. We characterized a novel modified microbial gum that better mimics gum arabic. This gum is produced from cane or beet sugar, providing a potential new value-added market for U.S. sugar producers. This work will be of interest to researchers, sugar producers, and food industry processors.

Technical Abstract: A novel modified alternan produced by a bioconversion process was physically characterized. High molecular weight native alternan was progressively modified to lower molecular weight heterodisperse forms, associated with a reduction in absorbance at 225 nm, light scattering, and opalescence. Modified alternan shows a linkage pattern generally similar to that of native alternan. The solution viscosity properties of modified alternan resemble those of ultrasonicated alternan and commercial gum arabic. However, alternan lacks the emulsification capacity of gum arabic. Alternan solutions are extremely stable at 4-37 deg C and at pH 3-9. Dry preparations of alternan are bright white powders that are not highly hygroscopic. Thus, modified alternan is promising for further development as a gum arabic substitute, especially for applications not requiring emulsification capacity.