Erwinia (E) gum, a stabilizer and thickening agent of food, is composed of glucose, fucose, galactose, and glucuronic acid (1 : 0.1 : 0.05 : 0.3 by molar ratio). The apparent weight-average molecular weight M-w and intrinsic viscosity [eta] in 0.2 M NaCl aqueous solution were measured to be 7.83 x 10(5) and 268 mL g(-1), respectively, by light scattering and viscometry. The aggregation behavior off gum in aqueous solution was investigated by gel permeation chromatography (GPC) and dynamic light scattering. The results showed that 7.5% E gum exists as an aggregate, whose diameter is 12 times greater than single-stranded chain, in aqueous solution at 25 degrees C, and the aggregates＇ content decreased with increasing temperature or decreasing polymer concentration. The aggregates at higher temperature were more readily broken than in exceeding dilute solution. GPC analysis proved that a significant shoulder, corresponding to a fraction of higher molecular weight due to chain aggregation, appeared in the chromatogram of E gum in 0.05 M KH2PO4/5.7 x 10(-3) M NaOH aqueous solution (pH 6.0) at 35 degrees C, and decreased with increasing temperature, finally disappeared at 90 degrees C. The disaggregation process of E gum in aqueous solution can be described as follows: with increasing temperature, large aggregates first were changed into the middle, then disrupted step by step into single-stranded chains. (C) 2000 John Wiley & Sons, Inc.