Investigation of kernels fluidizing in drying process on canola seed germination.

Drying can help to save quality of Canola seeds in the north provinces of Iran. Moisture content of Canola seeds reach to more than 20 % and causes to spoilage and harmful effects during storage. Canola seeds have to dried to 6-8 % moisture content for safe storage. Fluidized bed drying is one of the newest methods for food materials drying. It can be useful for Canola seeds drying process. In this research, desorption isotherms of Canola seeds investigated and modeled in the range of 30- 60 °C. Besides conditioned seeds with 20 % d.b moisture content were dried at 30, 40, 50 and 60°C and three bed conditions as fixed, semi fluidized and fluidized. All experiments were done by a batch type fluidized bed dryer that has made in Agricultural Engineering Research Institute (AERI) with three replication. Temperature and bed changes in the dryer were investigated on canola seeds drying kinetics. Also some dried seed properties such as final germination percent, emergence percent, seedling leaf area index and seedling dry mass percent compared with natural dried seeds as control. Experimental results showed that equilibrium moisture content of seed decreased with increasing temperature at constant relative humidity. Such as other food materials, relative humidity has direct relationship with equilibrium moisture content of canola seeds. In this research, Modified Oswin model had better fitness with experimental data than other models.In the drying process, increasing temperature from 30 to 60°C causes to increasing 70 percent in drying rate and 66.7 percent reduction in drying time for canola seeds. Besides, suitable aeration was observed in semi fluidized bed drying and after, it may causes to energy saving in drying process. Seeds bed changes had good effects on drying time and fluidizing of seeds decreased 23.5 percent of drying time in compare with fixed bed condition. Also bed changes form semi fluidized to fluidized causes about 8 percent increasing in the drying time. When using of high temperatures is limited in drying, fluidizing process can suitable for drying of heat sensitive materials. Finally, drying process at 30 and 40°C using semi fluidized beds is a good choice to drying canola seeds. It dose not have harmful effects on canola seeds cultivation properties and keep them above standard limit.