Ultrasonic-assisted enzymatic extraction of polysaccharide from Corbicula fluminea: Characterization and antioxidant activity

Ultrasonic-assisted enzymatic extraction (UAEE) technology was used to prepare Corbicula fluminea polysaccharide. Response surface methodology (RSM) and Doehlert matrix (DM) design were used to determine the optimum extraction conditions. The optimum extraction conditions consisted of the extraction time 32 min, ultrasound power 300 W, extraction temperature 62 degrees C and ratio of water to raw material 35 mL/g. The UAEE and enzyme-assisted extraction (EAE) methods were compared. The yield of UAEE for 32 min was higher than that of EAE for 4 h, which suggested that UAEE method has higher extraction efficiencies. The structures of crude polysaccharides obtained from UAEE and EAE were analyzed with FT-IR and HPLC methods. Their antioxidant activities were also evaluated on the basis of free radical scavenging. Compared with the polysaccharide (EP) extracted by EAE, the polysaccharide (EP-us) extracted by UAEE had lower molecular weight, higher sulfate content, and higher superoxide radical scavenging activity. (C) 2014 Elsevier Ltd. All rights reserved.