Effect of cooking on the drying behaviour of tarhana dough, a wheat flour–yoghurt mixture Original Research Article

Drying behaviour of tarhana dough before and after simmering at atmospheric pressure for 10 min was studied by changing the drying temperature (60–80 °C) and sample thickness (1–6 mm). The cooking process accelerated the drying process possibly due to increased porosity of dough by starch gelatinization. Fickʹs equation was used to calculate the diffusion coefficient for water (Deff) at different sample thicknesses. An increase in Deff values was observed at increased sample thickness for both normal and cooked dough. The Deff values for cooked dough were higher when compared to normal dough. Activation energies were calculated using an Arrhenius type equation to determine the effect of drying temperature on Deff values. It was found that Deff values are more sensitive to changes in drying temperature during drying of normal tarhana dough than during that of a cooked dough cooked, suggested by higher activation energies for normal tarhana dough.