Gelation mechanism of polysaccharides from Auricularia auricula-judae

Abstract

In the current study, dynamic frequency sweep and stress relaxation tests were performed to elucidate the possible gelation mechanisms of a unique thermal stable polysaccharides from Auricularia auricula-judae (AP). Addition of NaCl, CaCl2 and Ca-chelating agent (EDTA) to AP confirmed that electrostatic interaction was not the deciding force in forming the network of AP dispersion and the intrinsic calcium of AP played a role of inhibition in AP network formation. Addition of the hydrogen bond breaking agent, urea, highlighted the important role of hydrogen bonding in the formation of gel networks. The results suggested that carboxyl group of the uronic acid on AP chain are involved in the formation of inter/intra hydrogen bonding which maintain AP gel network. Quantitative effect of concentration, pH, urea and glucuronic acid on the network structure of AP dispersion were also be evaluated by entanglement network numbers (ENN) based on stress relaxation.