Rheological behavior of Senga Sengana strawberry mash

Abstract

The objectives of the research presented in this paper are rheological properties of a mash made of Senga Sengana strawberries. Organically grown strawberries were washed in cold water, blended and in order to be conserved, treated with sodium benzoate. Rheological properties of the mash with solids concentration of 10.53% were examined at a rotational rheometer at the temperatures of 20˚C, 30˚C and 40˚C. The aim of the research was to investigate the rheological properties (rheological behavior) of a strawberry mash with emphasis on the effects of temperature. It was found that the strawberry mash behaves as non-Newtonian, pseudo­plastic fluid, where the apparent viscosity decreases with increasing of shear rate (velocity gradient). The strawberry mash has thixotropic properties, where the apparent viscosity changes with time slowly and where the strawberry mash has no gel properties. Dependence of shear stress and the velocity gradient is modeled by Ostwald de-Waele equation. It was stated that the increase of a mash temperature leads to consistency index reduction and flow behavior index increase. The dependence of the apparent viscosity and temperature is modeled by Arrhenius equation, where the activation flow energy increases with shear rate reduction.

Keywords

• rheology
• mash
• strawberry
• senga sengana