Optimization of Ultrasonic/Microwave Assisted Extraction (UMAE) and Rheological Properties of Polysaccharides from Auricularia polytricha

Polysaccharides from Auricularia polytricha (APPS) were extracted using Ultrasonic/Microwave Assisted Extraction (UMAE) technology. UMAE conditions of APPS were optimized with Response Surface Methodology (RSM). Rheological properties of APPS were investigated. The results suggested that the optimal UMAE conditions for APPS were ratio of water to raw material 22 (mL/g), extraction time 15.3 min and microwave power 59W. APPS solution exhibited Newtonian flow behavior at low concentration, formed entanglement network at lower concentration and established weak gel structures with solid-like properties at higher concentration. The viscosity of APPS solutions decreased when temperature increased. The viscosity, storage (G') and loss (G") modulus of APPS solution increased when sucrose concentration increased. Heating time and freeze-thaw changes had no significant effect on rheological properties of APPS. The results suggested that UMAE was a suitable and efficient method for APPS extraction and APPS had potential as a novel food additive hydrocolloid in food industry.