Characterization of a novel modified alternan

A novel modified alteman, produced by using newly isolated strains of Penicillium sp., was physically characterized. High molecular weight native alteman was progressively modified to lower molecular weight heterodisperse forms, associated with a reduction in absorbance at 225 nm, light scattering, and opalescence. Methylation analysis indicated that modified alteman has a linkage pattern similar to that of native alteman. The solution viscosity properties of modified alternan resemble those of ultrasonicated alteman and commercial gum arabic. However, alteman lacks the emulsification capacity of gum arabic. Alternan solutions are stable for at least 7 days under all conditions tested, from 4 to 70 degreesC and from pH 3-9. Dry preparations of alteman are bright white powders that are not highly hygroscopic. Thus, modified alteman is promising for further development as a gum arabic substitute, particularly in food applications requiring a low-viscosity bulking agent. (C) 2003 Elsevier Ltd. All rights reserved.