Extraction and characterization of anti-oxidative polysaccharide-protein complexes from Corbicula fluminea through three-phase partitioning

In this study, a simple, efficient, and green bioseparation technology called three-phase partitioning (TPP) was employed to extract and separate polysaccharide-protein complexes (PSP) from Corbicula fluminea. The highest extraction yield of PSP was 9.0% under the following optimal conditions: 20% (w/v) ammonium sulfate concentration, 1.5 : 1.0 (v/v) t-butanol to crude extract ratio, 30 min, and 35 degrees C. This value was higher than the yield (7.6%) of E-PSP prepared through conventional enzyme extraction. The carbohydrate content (81.7%) of PSP was higher and its molecular weight (61.5 kDa; 72.4%) was lower than those of E-PSP. Although PSP and E-PSP are proteoglycans with different monosaccharide and amino acid compositions, their primary chemical structures did not remarkably differ after TPP was performed. The antioxidant activities of PSP were more evident than those of E-PSP in vitro. Thus, TPP could be potentially used for separation of active PS or PSP from natural sources.