Linear and nonlinear rheological behavior of native and debranched wazy rice starch gels

Suthsiri Precha Atsawanan, Dudsadee Uttapap, L.M.C. Sagis*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

18 Citations (Scopus)

Abstract

The rheological behaviours of native (WX) and debranched (DB) waxy rice starch gels in the linear viscoelastic (LVE) regime and non-linear (NL) regime were investigated using small amplitude oscillatory shear (SAOS), and large amplitude oscillatory shear (LAOS), respectively. Our results show that WX starch gels exhibited a wider LVE region than DB starch gels, and a scaling of G′ with frequency given by G’∼ω0.26. The G' and G” scaled nearly linear with concentration and were nearly independent of temperature in the tested range. The Lissajous plots showed a gradual yielding of the gels, followed by softening behavior. These results indicated that the WX gel has the characteristics of a weak particle gel (of non-entangled polymers). In contrast, the DB starch produced gels with a more stiff and brittle behavior. The shear moduli had a very strong concentration dependence (∼C10.30) and temperature dependence. The DB starch gel showed more abrupt yielding and strong softening behavior in the Lissajous curves. Creep measurements showed a lower compliance for these gels, and significant creep ringing. These observations suggest the DB starch gels consist of clusters of stiff polymers.
Original languageEnglish
Pages (from-to)1-9
JournalFood Hydrocolloids
Volume85
DOIs
Publication statusPublished - Dec 2018

Keywords

  • debranched starch
  • non-linear rheology
  • lissajous plot
  • creep testing
  • large amplitude oscillatory shear (LAOS)

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