Journal de la transformation et de la technologie des aliments

Abstrait

The Rheological Modeling and Effect of Temperature on Steady Shear Flow Behavior of Cordia abyssinica Gum

Ali Rafe and Masood HS

Steady shear rheological properties of Cordia abyssinica gum, as a novel hydrocolloid, were investigated at different temperatures (30-50°C). The apparent viscosity was drastically affected by temperature, and decreased from 234.9 to 7.46 Pa.s. Cordia gum was exhibited pseudoplastic behavior, which being almost Newtonian at 50°C. Different models including Powerlaw, Herschel-Bulkley and Casson were applied to model rheological trait. The Results were shown that the Herschel-Bulkley model has the best fitness with experimental data. Ascending and descending viscometry data were shown a weak thixotropic behavior particularly at low shear rates. By increasing the temperature in both curves, n decreased and k increased. The apparent viscosities of Cordia gum followed an Arrhenius model and the ηo increased and activation energy diminished as shear rate decreased from 330 to 15/s. Low values of the activation energy implied that Cordia gum can maintain its viscosity at higher temperatures more than BSG and Xanthan. It has a high potential for application in food and neutaceutical products as possess yield stress and pseudoplastic behavior, which enables it to use as an emulsifier, stabilizer or excipient in tablet formulations.