Rheological properties of cooked tarhana, a cereal-based soup

The rheological behaviour of tarhana, a popular Turkish fermented wheat flour–yoghurt soup, was studied at different temperatures (30 to 70 °C). Results showed that an increase in shear rate resulted in a decrease in apparent viscosity, suggesting pseudoplastic behaviour at all temperatures studied. A power law equation was used to calculate the flow behaviour indices, n , ranging from 0.52 to 0.87. The n values were higher for the soups made from wholemeal flour than obtained for the soups made from white wheat flour. Consistency indices decreased with temperature and were described by the Arrhenius equation with activation energies from 48.6 to 28.6 kJ/mol.