FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Profile of convective drying process of osmotically dehydrated apples in sucrose solution


The objective and scope of the paper included the determination of the effect of three factors on the drying process and on some selected properties of the dried material. The 3 factors analyzed were: temperature; air flow rate in the drying chamber of convective dryer; osmotic dehydration time of apples in sucrose solution at a temperature of 30 °C. The selected parameters were: drying time necessary to achieve 10 % moisture in the dried material and drying rate being achieved at this moisture level; water diffusion coefficient, final content (i.e. equilibrium content under the specific drying conditions) and activity of water in the dried material produced. It has been proved that the temperature has a significant effect on the selected and analyzed parameters characterizing the drying process, as well as on the dried apples produced in the investigated range of variability of temperature, air flow rate and osmotic dehydration time. Based on the analysis of dependencies obtained, it was possible to prove that the increase in drying temperature ranging from 55 to 85 °C caused the final (equilibrium) water content and the activity of dried apples being osmotically pre-treated to decrease. At the same time, the increase in the drying temperature caused the drying process to accelerate and the time necessary to obtain 10 % moisture to be reduced.


dried apples, convective drying, osmotic dehydration, experiment schedule