Natural Giesekus fluids: Shear and extensional behavior of food gum solutions in the semidilute regime |
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| Authors: | Maria D Torres Bart Hallmark D Ian Wilson Loic Hilliou |
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| Affiliation: | 1. Dept. of Chemical Engineering and Biotechnology, New Museums Site, University of Cambridge, Pembroke St, Cambridge, U.K.;2. Dept. of Chemical Engineering, University of Santiago de Compostela, Lope Gómez de Marzoa St, Santiago de Compostela, Spain;3. Dept. of Polymer Engineering, University of Minho, Campus de Azurém, Guimar?es, Portugal |
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| Abstract: | The shear and extensional behavior of two aqueous gum solutions, namely (1) 1–20 g/L guar gum (Torres et al., Food Hydrocolloids. 2014;40:85–95) and (2) κ/ι‐hybrid carrageenan solutions (5–20 g/L), are shown to exhibit Giesekus‐fluid behavior when in the semidilute regime. In this regime, a common set of Giesekus fluid parameters described both shear and extensional behavior. A new analytical result describing the extension of a Giesekus fluid in the filament stretching geometry is presented. This also gave reasonable predictions of the Trouton ratio. Higher concentration guar solutions, in the entangled regime, yielded different Giesekus fluid parameters for extension to those for simple shear. The extensional data for all concentrations of both gums collapsed to a common functional form, similar to that reported for cake batters (Chesterton et al., J Food Eng. 2011;105(2):332–342); the limits of the new filament thinning expression provide insight into this behavior. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3902–3915, 2014 |
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| Keywords: | concentration regimes extensional rheology guar gum Giesekus fluid κ /ι ‐hybrid carrageenan gum shear rheology Trouton ratio |
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