Shear-induced aggregate formation in starch solutions
نویسندگان
چکیده
Shear-thickening behavior and shear-induced pattern formation have been observed in semidilute starch solutions. While the shear-thickening behavior is due to breaking up of highly concentrated gel-like structures dispersed in dilute starch solutions, the pattern-forming behavior is not well understood. The pattern formation, observed when the starch solution is exposed to a high shear field, is a consequence of shear-induced aggregation and is not related to shear-thickening behavior. The patterns have been observed above a certain critical threshold shear rate regardless of the starch type. In this report, it is shown that the product of shear time and fourth power of shear rate is a controlling factor for the formation of shear-induced aggregates in starch solutions. Since starch solutions prepared under harsh conditions did not show shear-induced aggregate formation, it is suggested that the aggregates are formed from incompletely solubilized starch residues in its apparent solution. Published by Elsevier Ltd.
منابع مشابه
Shear - induced aggregation and break up of fibril clusters close to the percolation concentration
Structural changes of complex fluids under steady shear flow were investigated for different type of materials, such as suspensions, associating polymers and polymer solutions [1, 2, 3, 4, 5, 6]. Under specific conditions, depending on the material, a shear-thickening regime is observed followed by shear-thinning behaviour [3, 4, 6]. Shear-thickening is often the result of shear-induced formati...
متن کاملShear thickening in dilute solutions of wormlike micelles
– A new mechanism is suggested for shear thickening in dilute solutions of wormlike micelles. According to this mechanism, there is an instability above a critical shear rate, γ̇c, by which micelles aggregate to form networks of bundles. We examine the first step of this instability by studying the aggregation of two micelles into a paired bundle. The model predicts that γ̇c is given by the inver...
متن کاملMolecular basis for Staphylococcus aureus-mediated platelet aggregate formation under arterial shear in vitro.
OBJECTIVE Staphylococcus aureus is the most frequent causative organism of infective endocarditis (IE) and is characterized by thrombus formation on a cardiac valve that can embolize to a distant site. Previously, we showed that S. aureus clumping factor A (ClfA) and fibronectin-binding protein A (FnBPA) can stimulate rapid platelet aggregation. METHODS AND RESULTS In this study we investigat...
متن کاملPhysicochemical Parameters Study of Chitosan-starch- Glutaric Acid in Acetic Acid-water Mixtures
Knowledge of the physicochemical parameters values produced by the utilization of the polymer blends is important because of the effect that it has on the operational cost of several stages of the industrial process Chitosan/starch solutions of different variable concentrations from (90/10 to10/90) are prepared in dilute acetic acid solution (1%). Glutaric acid solution concentration is 1% fixe...
متن کاملStructure, Rheology and Organoleptic Properties of Starch Pastes - New Developments
Understanding consumer perception of the organoleptic qualities of a food product in terms of rheological properties is a major challenge for food scientists, and has been studied for a long time. As early as 1962 Szczesniak and Farkas (1962) reported a relationship between the mouthfeel of thickened solutions and their rheological behaviour. In this work, thickeners were categorised based on p...
متن کامل