Rheological behaviors of an exopolysaccharide from fermentation medium of a Cordyceps sinensis fungus (Cs-HK1)

Fengyuan Sun, Qilin Huang, Jianyong Wu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

29 Citations (Scopus)

Abstract

The rheological behaviors of an exopolysaccharide (EPS) from a Cordyceps sinensis fungus fermentation were investigated. The intrinsic viscosity of 1986 ± 55 mL/g indicated an extended and rigid chain for EPS. Shear-thinning behavior was observed and became apparent with increasing concentration. According to cross model, two critical transition concentrations (c∗and c∗∗) from dilute solution to semidilute and then to concentrated domain were 0.45 and 6.14 mg/mL. Flow activation energy was calculated by Arrhenius equation and decreased with increasing concentration, indicating a lower sensitivity to temperature. From dynamic frequency sweep, EPS system was classified to three regions including dilution solution (1.25 mg/mL), entanglement network (3.75 and 5.00 mg/mL) and weak gel (≥7.50 mg/mL). Notably, the increase in η∗at high frequencies was attributed to a large flow resistance depended on the rigid chain of EPS. Based on Winter-Chambon criterion, EPS formed gel at 2.6 mg/mL (cgel) and showed typical weak gel from temperature ramp and repetitive strain sweep.
Original languageEnglish
Pages (from-to)506-513
Number of pages8
JournalCarbohydrate Polymers
Volume114
DOIs
Publication statusPublished - 19 Dec 2014

Keywords

  • Cordyceps sinensis
  • Exopolysaccharide
  • Rheological behaviors

ASJC Scopus subject areas

  • Organic Chemistry
  • Materials Chemistry
  • Polymers and Plastics
  • Medicine(all)

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