Extraction, characterization and antioxidant activities of polysaccharides from E. corneum gigeriae galli

•Polysaccharides from E. corneum gigeriae galli (PEGG) were extracted.•Optimal technological conditions of enzyme-assisted extraction for PEGG were investigated.•PEGG contained protein and uronic acid and had relatively high content of sulfate radical.•PEGG showed a significant antioxidant activities in vitro.

In the present study, optimization of enzyme-assisted extraction, characterization and antioxidant activities in vitro of polysaccharides from Endothelium corneum gigeriae galli (PEGG) were investigated. It was found that the optimum extraction conditions were determined as follows: extraction temperature 87.0 °C, extraction time 177.0 min, enzyme concentration 1.65%, enzymatic hydrolysis time 141.0 min, liquid-to-solid ratio 20, enzymatic hydrolysis temperature 55 °C and enzymatic hydrolysis pH 3.6. Under these conditions, the experimental yield of polysaccharides was 5.08%. In addition, PEGG had a relatively high sulfate radical content. PEGG was composed of rhamnose, fucose, mannose, glucose and galactose, with molar percentages of 13.1, 4.5, 72.8 and 9.6%, respectively. The average molecular weight was 83 kDa. And there were infrared characteristic absorption peaks of polysaccharides in the FT-IR spectroscopy of PEGG. For antioxidant activities in vitro, PEGG showed possessed strong hydroxyl radical scavenging, Fe2+ chelating and lipid peroxidation inhibitory activities.