Galactomannans obtained from Cassia javanica, Caesalpinia pulcherrima and Prosopis juliflora seeds, as well as commercial samples of locust bean gum (LBG) and guar gum (GG), were submitted to extraction and purification procedures. Viscometric measurements of their dilute aqueous solutions were performed in a Low Shear 40 rheometer in the shear rate range of 10(-3) to 10(2) s(-1). To obtain the intrinsic viscosity of these galactomannans, additional purification procedures, filtration through 0.45 mum membranes or centrifugation at 12 000 rpm for 1 h, were carried out. Intrinsic viscosities and Huggins' coefficient values were substantially different, depending on the purification method used. The results were attributed to differences in fine structure. (C) 2002 Elsevier Science Ltd. All rights reserved.
