Rheological properties of cooked tarhana, a cereal-based soup

The rheological behaviour of tarhana, a popular Turkish fermented wheat flo ur-yoghurt soup, was studied at different temperatures (30 to 70 degrees C) . Results showed that an increase in shear rate resulted in a decrease in a pparent viscosity, suggesting pseudoplastic behaviour at all temperatures s tudied. A power law equation was used to calculate the flow behaviour indic es, n, ranging from 0.52 to 0.87. The n values were higher for the soups ma de from wholemeal flour than obtained for the soups made from white wheat f lour. Consistency indices decreased with temperature and were described by the Arrhenius equation with activation energies from 48.6 to 28.6 kJ/mol. ( C) 1999 Canadian Institute of Food Science and Technology. Published by Els evier Science Ltd. All rights reserved.