Study on the sol–gel transition of xyloglucan hydrogels

Abstract

Partially degalactosylated xyloglucan is a temperature-responsive polymer very promising for biotechnological purposes. We have studied the sol–gel transition of xyloglucan hydrogels with different galactose removal ratios. Rheological analysis was carried out, and the sol–gel transition temperature was determined at the cross-over point of G′ and G″. As a general trend, the sol–gel transition temperature was reduced as the galactose removal ratio increased, and at higher polymer concentrations. The reversible gelation was studied, and a thermal hysteresis was for the first time observed and discussed. The intrinsic viscosity [ η] values of the samples and the molar mass decreased with increasing galactose removal. Light scattering analysis demonstrated that the increase in the hydrophobic content by galactose removal induced an increase in polymer–polymer interactions and a change in the molecule conformation to a more compact structure.