USING DEHYDRATED AIR IN DRYING GARLIC SLICES

The aim of this study is to investigate a new drying method that depend on absorbing the moisture from the air using some desiccants which have a great affinity for moisture; so when the wet air passes through the desiccants it becomes less wet and its temperature becomes a little higher ranging from 2 to 4°C. The used desiccants were sulfuric acid conc., calcium chloride anhydrous and silica gel. The experiments were done in two stages the first stage was without drying load on purpose of choosing the best treatment that provides high dehydrated air. The best treatment for dehydrating the air was when air passes with the lowest velocity 2.0 m/s in succession through four desiccants; 500ml H_2SO_4, 500g CaCl_2, 500ml H_2SO_4 and 500g SiO_2, with moisture uptake percentage from 56.77% to 18.2%. In the second stage we used oven dryer at 70 °C and Desiccant Drying System (DDS) with the best treatment in drying garlic with slices thickness 3 mm. Three levels of loading were used 1.15, 2.3 and 4 .6 Kg/m². The quality of the dried garlic slices were evaluated for color and oil content. The results revealed that using the DDS method provides a good quality dehydrated garlic slices with higher oil content and lower color change. It also involved low energy consumption and high drying efficiency compared to the slices dried by using oven dryer.