Chain conformation and rheological properties of an acid-extracted polysaccharide from peanut sediment of aqueous extraction process

• Published in: Carbohydrate polymers 2020-01, Vol.228, p.115410-115410, Article 115410
• Main Authors: Ye, Jianfen, Hua, Xiao, Zhao, Qiyan, Zhao, Wei, Chu, Guanhe, Zhang, Wenbin, Yang, Ruijin
• Format: Article
• Language: English
• Subjects: Chain conformation; Molecular morphology; Newtonian behavior; Peanut polysaccharide; Rheological properties
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2019.115410

[Display omitted] •PPS mainly consisted of Ara, GalA, Xyl and Rha.•Compact coil chain with branched conformation was obtained by HPSEC-MALLS.•Molecular self-association played an important role on conformation behavior.•Newtonian behavior of PPS solution was observed at different concentration.•10.0 wt.% of PPS solution was structured liquid. A polysaccharide (PPS) in peanut sediment of aqueous extraction process was obtained at pH4.0, purified via anion-exchange chromatography. The composition, chain conformation and rheological properties were investigated. PPS mainly consisted of arabinose, galacturonic acid, xylose, and rhamnose. The intrinsic viscosity [η] was 0.71 dL/g in 0.1 M NaNO3 solution. The weight-average molar mass Mw and polydispersity index were 3.77 × 105 g/mol and 1.25, suggesting high homogeneity. The average radius of gyration (Rg), hydrodynamic radius (Rh), Rg/Rh ratio and conformation parameter v were 25.5, 18.2, 1.40 and 0.21, respectively, indicating compact coil chain conformation with branched structure. Molecular morphology revealed that PPS displayed chain shape comprised of spheres with a diameter range of 15–50 nm and apparent length of chains mainly ranged from 100 to 300 nm. The aggregation caused by molecular self-association enhanced with concentration increasing. Additionally, Newtonian behavior was observed at various concentrations. Increase in temperature effectively broke this behavior. 10.0 wt.% PPS possessed activation energy of 21.7 KJ/mol, was structured liquid and almost fitted Cox-Merz rule. These closely related with its conformation and molecular self-association behavior.