title: Optimized extraction and molecular characterization of polysaccharides from Sophora alopecuroides L. seeds.
abstract: Optimized extraction of crude polysaccharides from Sophora alopecuroides L. seeds (CSAP) was firstly investigated, and the results were extraction time 4.15 h, extraction temperature 70.68°C and water/seed ratio 50.99:1 ml/g. At this proximal point, highest yield (10.88%) and relative viscosity (1.2952) were obtained for CSAP, which contained 78.40% sugar, 6.08% protein, 9.71% ash, 7.16% moisture and 1.88% uronic acid. Neutral fractions of F15, F25, F35 and F60 were further obtained via stepwise alcohol precipitation. Results of monosaccharide composition indicated that CSAP and its neutral fractions mainly consisted of mannose and galactose (79.45-97.52%) with M/G ratios of 0.94-1.48, typical for galactomannans, which were demonstrated by FT-IR. Weight-average molecular weight, radius of gyration and hydrodynamic radius were in the same order (F15>F25>F35>F60), whereas the highest intrinsic viscosity was observed for F25. Multiple analyses, including Mark-Houwink-Sakurada exponent (0.48-0.80), persistence length (1.45-3.93 nm), conformation zoning (random coil) and power-law exponent (b>1), showed flexible coils for all neutral fractions. Concerning viscometry, there were no aggregates (K″ 0.60) or coil overlaps ("master curve") of F25 in dilute solutions. Relatively weak surface activity of F25 was probably related to its particular chemical structure and proteinaceous moieties closely conjoined.
authors.affiliation: Key Laboratory of Urban Agriculture (South), School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.affiliation: Key Laboratory of Urban Agriculture (South), School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Nannan
authors.initials: N
authors.lastname: Cao
authors.affiliation: Key Laboratory of Urban Agriculture (South), School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: wuy@sjtu.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Urban Agriculture (South), School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Jinhong
authors.initials: J
authors.lastname: Wu
mesh_terms: D005591:Chemical Fractionation / Q000379:methods; D008970:Molecular Weight; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification*; D012639:Seeds / Q000737:chemistry*; D029909:Sophora / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013500:Surface Tension; D014783:Viscosity
chemical_list: D010936:Plant Extracts; D011134:Polysaccharides
keywords: Extraction; Molecular characterization; Polysaccharides; Sophora alopecuroides L. seeds; Viscometry