In vitro binding capacities, physicochemical properties and structural characteristics of polysaccharides fractionated from Passiflora edulis peel

This study aimed to determine structural characteristics, physical properties and binding effects of polysaccharide and its fractions from Passiflora edulis peel on lipid , cholesterol and bile acids . The crude polysaccharide (WPEP) was extracted using hot water extraction method, fractionated using DEAE-52 cellulose column, and purified by Sepharose CL-6B column to obtain four polysaccharide fractions (WPEP-F1, WPEP-F2, WPEP-F3, and WPEP-F4). The physicochemical properties and structural characteristics were analyzed using several methods. The chemical-binding effects were also determined. Among all polysaccharide samples, WPEP-F2 had the highest total sugar content (77.63%). The viscosity of all polysaccharide samples was increased. Among the four polysaccharide fractions, WPEP-F2 showed the best emulsifying activity. WPEP-F1 was mainly composed of glucose, galactose , mannose , and arabinose , whereas WPEP-F2, WPEP-F3, and WPEP-F4 were principally composed of galacturonic acid. SEM analysis showed that the four fractions had different microstructures. Among the polysaccharide components, WPEP-F2 had the highest lipid-binding effect (9.3 g/g). It also had the best binding effect on taurocholic acid , deoxycholic acid , glycocholic acid , and cholesterol (50.87%, 69.12%, 30.22%, and 78.68%, respectively), but WPEP-F3 had the best binding effect on cholic acid (53.99%). The lipid, cholesterol, and bile acid-binding activities of WPEP-F2 could be attributed to its high viscosity, porous appearance structure, and sugar content in addition to its triple helix structure. The findings lay a theoretical foundation for developing Passiflora edulis peel polysaccharide-related foods and promoting application of the peel polysaccharide in functional food industries.