MECHANICAL AND MORPHOLOGICAL FEATURES OF AGAROSE GUAR GUM GELS

Young's modulus, maximum rupture stress and compression energy to brea k values were determined for pure agarose (5g/1 and 10g/1) and 1:1 aga rose-guar gum mixed gels of 10g/1 total polymer concentration. The enh ancing effect of guar gum was noticed particularly on the tenacity par ameter, Transmission electron microscopy, TEM, was used to image the s upramolecular structure of 1:1 agarose-guar gum gels. Before sample pr eparation for TEM, the hot aqueous solutions have been submitted to sl ow cooling until a determined temperature was reached, and then quench ed to -78 degrees C. When this temperature was higher than the critica l temperature of gelation, agarose-guar gum mixed samples formed aggre gated structures, promoted by freezing. Below gelation, although guar gum continued producing aggregates, agarose appeared as continuous net work structures. This result was related to the stabilizing role of gu ar gum.