Thin-layer drying characteristics of kurut, a Turkish dried dairy by-product

Kurut, which is made in villages of Eastern part of Turkey, is a sun-dried dairy product. Thin-layer drying behaviour of kurut at a temperature range of 35-60 degrees C, with 5 degrees C increments, and constant thickness of 0.5 cm and drying air velocity of 1.5 in s(-1) was determined in a convective type dryer. The data of sample weight, dry and wet-bulb temperatures were recorded continuously during each experiment and drying curves obtained. The drying process took place in the falling rate period. Drying curves were then fitted to eleven mathematical models available in the literature to estimate a suitable model for drying of kurut. Two-term model gave better predictions than other models and satisfactorily described the thin-layer characteristics of kurut.. The effective diffusivity varied from 2.444 x 10(-9) to 3.597 X 10(-9) M2 s(-1) over the temperature range. The temperature dependence of diffusivity coefficient was described by the Arrhenius-type relationship. The activation energy for moisture diffusivity was found to be 19.88 kJ mot(-1).