Amylase-assisted extraction and antioxidant activity of polysaccharides from Gracilaria lemaneiformis.

Gracilaria lemaneiformis (G. lemaneiformis) is rich in polysaccharides that have many functional activities. In this study, the thermostable α-amylase-assisted extraction and antioxidant activity of water-soluble polysaccharides from G. lemaneiformis were investigated. The extraction conditions were optimized as follows: time, 40 min; temperature, 95 °C; pH, 5 and enzyme amount, 6000 U/g, under which the yield of G. lemaneiformis polysaccharides (GPs) reached 49.15% dry base. The GPs were characterized by monosaccharide composition, FTIR spectrum, UV spectrum and antioxidant activities. The results indicate that the GPs had strong hydroxyl radical activity at a concentration of 100 μg/mL and could be used as potential antioxidants.