Relation between concentration and shear-extensional rheology properties of xanthan and guar gum solutions
2018 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, p. 63-70Article in journal (Refereed) Published
Abstract [en]
The influence of concentration on the shear and extensional rheology properties of aqueous solutions of xanthan and guar gums was studied in this work. Shear rheology involved small amplitude oscillatory shear (SAOS), flow curves and transient flow, while the extensional rheology was analyzed using hyperbolic contraction flow. In addition, the mechanical properties during solutions manufacture were monitored in situ through the evolution of torque with processing time by mixing rheometry. The results showed that the hydrocolloids exert a great influence on the process rheokinetics and on the resulting rheological response. SAOS tests showed that the xanthan gum solutions behaved as weak gels, whereas guar gum solutions suggest the presence of entanglement and the formation of a viscoelastic, gel-like structure. All the systems exhibited shear-thinning behaviour. Guar gum solutions obeyed the Cox-Merz rule, with some divergence at high rates for the more concentrated solutions, while the Cox-Merz rule was not followed for xanthan gum in the range of concentration studied. The extensional viscosity exhibited an extensional-thinning behaviour within the strain range used and all solutions were characterized by a high Trouton ratio.
Place, publisher, year, edition, pages
2018. Vol. 181, p. 63-70
Keywords [en]
Flow behaviour, Polysaccharides solutions, Shear thickening, Viscoelasticity, Elasticity, In situ processing, Non Newtonian flow, Processing, Shear flow, Shear thinning, Solutions, Concentrated solution, Extensional rheology, Extensional viscosity, Flow behaviours, Oscillatory shear, Polysaccharides solution, Rheological response, Xanthan gum
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-36580DOI: 10.1016/j.carbpol.2017.10.057Scopus ID: 2-s2.0-85031723617OAI: oai:DiVA.org:ri-36580DiVA, id: diva2:1268783
Note
Funding details: ceiA3;
2018-12-062018-12-062023-05-25Bibliographically approved