Three-phase partitioning for efficient extraction and separation of polysaccharides from Corbicula fluminea

Three-phase partitioning (TPP), which is a simple, efficient, and green bioseparation technique, was used to extract and separate polysaccharides from Corbicula fluminea (CFPS). The optimal parameters with a high yield of 9.32% were as follows: mass fraction of (NH4)2SO4, 20.0% (w/v); amount of t-butanol, 9.8 mL; temperature, 35.3 °C; extraction time, 30 min; and pH 6.0. The purified CFPS after TPP consisted of d-glucose, d-glucosamine, and d-mannose in a molar ratio of 57.1: 5.6:1.0 with high purity (86.5%) and different molecular weights (1311.1 and 41.5-92.8 kDa). Amino acid analysis, UV-vis absorption and Fourier transform-infrared spectra indicated that the purified CFPS was a proteoglycan with O-glycosidic bonds. Moreover, the purified CFPS possessed strong free-radical scavenging abilities and antioxidant activities in vitro. The obtained Trolox equivalent antioxidant capacity and ferric-reducing ability of plasma values were 95.01 μmol Trolox/g sample and 38.30 μmol Fe2+/g sample, respectively.