Abstract:

In the present work, surface tensions of LBG (locust bean) and guar gum have been studied. It has been demonstrated that galactomannans, although highly hydrophilic in nature, can adsorb at interfaces, reducing surface tension to levels whereby they can be categorized as surfactants. Surface tensions of LBG solns. with ethoxylated sorbitan trioleate indicate the formation of a new species (complexes) with improved surface properties. The viscosities of aq. solns. of guar gum, LBG and their mixts. with ethoxylated mono- and trioleates (Tween 80 and 85) were measured at different shear rates. At high emulsifier concns. (5.0 gr/dL) a significant increase in viscosity is shown with Tween 85 in comparison to a sharp decrease with Tween 80. Both LBG and guar gum exhibited similar performance. The results are discussed in relation to the mol. structure of the galactomannan-emulsifier complex and the hydrophobicity of the constituents. [on SciFinder(R)]