Synergistic rheological behavior and morphology of yam starch and Auricularia auricula-judae polysaccharide-composite gels under processing conditions.

Polysaccharides from Auricularia auricula-judae (AP) have unique functionalities. The influence of AP-blending ratios (0.1-0.8%), temperature, pH, and ionic strength on the rheological interactions of yam starch (YS)-AP blends (YA, 6%) was investigated. YA gels showed shear-thinning behavior with flow-behavior indices of 0.28-0.37 and greater pseudoplasticity in the presence of 0.8% AP. With incremental AP addition, the viscosity and consistency indices significantly increased, whereas the activation energy decreased from 7.55 to 5.12 kJ/mol (p < 0.05). YA gels exhibited excellent thickening and heat tolerance and behaved as weak gels over an AP concentration range of 0.1-0.4% but as true gels at higher concentrations (e.g. 0.8%). The viscosity/elasticity of the combinations weakened with NaCl addition or extreme pH values. A complex 3-dimensional network structure of the YA system was confirmed by scanning electron microscopy. These results indicated that AP has great potential for functional applications in the starchy food industry.