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

Jianfen Ye; Xiao Hua; Qiyan Zhao; Wei Zhao; Guanhe Chu; Wenbin Zhang; Ruijin Yang

doi:10.1016/j.carbpol.2019.115410

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

Carbohydr Polym. 2020 Jan 15:228:115410. doi: 10.1016/j.carbpol.2019.115410. Epub 2019 Sep 30.

Authors

Jianfen Ye¹, Xiao Hua¹, Qiyan Zhao¹, Wei Zhao¹, Guanhe Chu¹, Wenbin Zhang¹, Ruijin Yang²

Affiliations

¹ State Key Laboratory of Food Science & Technology, School of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.
² State Key Laboratory of Food Science & Technology, School of Food Science and Technology, Jiangnan University, 214122, Wuxi, China. Electronic address: yrjjiangnan@126.com.

PMID: 31635751
DOI: 10.1016/j.carbpol.2019.115410

Abstract

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 (R_g), hydrodynamic radius (R_h), R_g/R_h 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.

Keywords: Chain conformation; Molecular morphology; Newtonian behavior; Peanut polysaccharide; Rheological properties.