Abstract
Structurally modified guar galactomannans find application in food and petroleum industries as rheology modifiers. Enzymes provide a powerful and convenient method to modify guar structure. In this study, the kinetics of enzymatic degradation of guar solutions were investigated using SEC and rheology. Molecular information from SEC reveals the degradation reaction to be zeroth order in guar concentration. Further, the rate constant was proportional to enzyme concentration, demonstrating that the enzyme acts as a true catalyst. The zero shear viscosity was very sensitive to degradation, with several orders of magnitude change being observed over the course of polymer chain scission. A unique correlation was developed between degradation time, guar molecular weight and viscosity. This enables superposition of the viscosity-time profiles for different enzyme concentrations to a master curve; providing for a priori prediction of guar solution viscosity as a function of degradation time and enzyme concentration.
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© 2002 Kluwer Academic Publishers
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Tayal, A., Pai, V., Kelly, R.M., Khan, S.A. (2002). Enzymatic Modification of Guar Solutions. In: Amjad, Z. (eds) Water Soluble Polymers. Springer, Boston, MA. https://doi.org/10.1007/0-306-46915-4_4
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DOI: https://doi.org/10.1007/0-306-46915-4_4
Publisher Name: Springer, Boston, MA
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