# Evaluation of Design Parameters on Drying of Kiwi Fruit
## 3 Results and Discussions  
### Results of Experiments  
The experiments examining the effect of air velocity on drying in the drying process of the kiwifruit were carried out for 0.5, 1.0 and 1.5 m/s of air at 45 \({}^{\circ}\)C and a relative humidity of 10%. Fresh kiwi samples with slice thickness of 4 mm and 8 mm were used in the experiments. The dryer was adjusted to be selected drying air temperature for about one an hour prior to the start of experiment to achieve the steady-state conditions. Fresh kiwi fruits were used in this study. Achieving 3 h stabilization under the ambient temperature conditions, homogenous samples were first hygiized then cored with a knife and then cut vertically to their axis into cylindrical slices of 4 and 8 mm thickness by a mechanical cutter. Then 142 g of kiwifruit was placed on the drying tray. The mass loss of the kiwifruit during drying was measured from the scale for every 15 min. The chamber was installed under the laboratory conditions that were a relative humidity of between 20% and 45% and a temperature of between 22 and 28 \({}^{\circ}\)C. The drying was carried out to final moisture content of 10% from initial moisture content of about 80%. View of kiwi fruits used in this study given in Figure 2a-c. The drying phases of the kiwifruit are photographed. Fresh kiwifruits used in this study are given in Figure 2a the kiwi samples placed in the drying cabinet are shown in Figure 2b (on the left); dried kiwi samples are shown in Figure 2b (on the right). The dried kiwi samples with thickness of 4 mm and 8 mm are shown in Figure 2c. The moisture content of the product, as a function of drying time, is shown in Figure 3 for the kiwifruit with a thickness of 4 mm, the drying air temperature of 45 \({}^{\circ}\)C and the drying air velocity of 0.5 m/s, 1 m/s and 1.5 m/s. As seen from the drying curves, the drying air velocity has affected the moisture content of the kiwifruit. The lowest drying time (225 min) was achieved with a thickness of 4 mm and a drying speed of 1.5 m/s. The highest drying time (360 min) was obtained for a thickness of 4 mm and a drying speed of 0.5 m/s. The moisture content of the product, as a function of drying time, is shown in Figure 4 for the kiwi fruit with a thickness of 8 mm, the drying air temperature of 45 \({}^{\circ}\)C and the drying air velocity of 0.5 m/s, 1 m/s and 1.5 m/s. The lowest drying time (420 min) was achieved with a thickness of 8 mm and a drying speed of 1.5 m/s. The highest drying time (750 min) was found for a thickness of 8 mm and a drying speed of 0.5 m/s. This value is followed by 540 min (8 mm and 1 m/s). Figure 2: View of kiwi fruits used in this study, (**a**) Fresh kiwi fruits, (**b**) The view of the kiwi fruits in the dryer chamber (in **left**) and the view of the dried kiwi fruits (in **right**), (**c**) The view of the dried kiwi fruits for slice thickness of 4 mm (in **left**) and dried kiwi fruits for slice thickness of 8 mm (in **right**). Figures 5 and 6, as a function of drying time, shows the change in drying rate. This change was given for the kiwifruit with a thickness of 4 mm and 8 mm and air temperature of 45 \({}^{\circ}\)C at air velocity of 0.5, 1 and 1.5 m/s. The drying rate decreases continuously with increasing drying time. It was tested that the main factor influencing drying rate is the drying air velocity, as reported in earlier studies [21; 22]. Figure 4: Moisture content wet basis as a function of drying time for drying air velocity of 0.5, 1 and 1.5 m/s and slice thicknesses of 8 mm for kiwi fruits. Figure 5: Drying rate as a function of drying time for drying air velocity of 0.5, 1 and 1.5 m/s and slice thicknesses of 4 mm for kiwi fruits. Figure 3: Moisture content wet basis as a function of drying time for drying air velocity of 0.5, 1 and 1.5 m/s and slice thicknesses of 4 mm for kiwi fruits. The internal temperature of the product is shown in Figure 7 for the kiwifruit with a thickness of 4 mm, air temperature of 45 \({}^{\circ}\)C at a drying air velocity of 0.5 m/s, 1 m/s and 1.5 m/s.