食品加工与技术杂志

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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.