Time‐dependent phenomena as evidence for structure‐forming properties of starches. Issue 3 (19th September 2013)

• Record Type: Journal Article
• Authors: Ptaszek, Anna
• Is Part Of: Stärke. Volume 66:Issue 3/4(2014)
• Page Start: 326
• Page End: 336
• Publication Date: 2013-09-19
• Subjects: Starch -- Periodicals; 572.566
• DOI: 10.1002/star.201300113
• Languages: English
• ISSNs: 0038-9056

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="star201300113-sec-0001" sec-type="section"> <p>The study discusses the rheological properties of four different starches (amylose (AM), potato starch (P), waxy potato starch (WXP), and maize amylopectin (AP)) in the form of aqueous pastes and solutions in DMSO. Additionally, osmotic characteristics of diluted solutions of these starches are presented. The results of the qualitative hysteresis loop tests revealed that AM paste and AM solution in DMSO are rheologically stable fluids. Using the scaling of the concentration, it has been shown that the behavior of AM paste is complex. AP and WXP in form of pastes and their solutions in DMSO are rheologically unstable fluids. The course of the flow curves, carried out at the decreasing shear rate, indicates that AP paste accumulates energy. Equilibrium tests performed using AP paste, AP, WXP 1 and 5% solutions in DMSO showed a few interesting effects (chaotic behavior, oscillations, no change, small increase or decrease in apparent viscosity as a function of time). The nature of time‐dependent type phenomena, however, hinders the application of the Cheng and Evans viscosity theories to describe and model the rheological behavior. As the study results demonstrate, the rheological instability of the starch solutions is also based on the phenomena of energy accumulation, i.e. in viscoelastic effects.</p> </sec> </abstract>