Agglomeration mechanisms of cassava starch during pneumatic conveying drying

This study aimed to investigate the agglomeration mechanisms of cassava starch during pneumatic conveying drying based on phase transition concept. Glass transition and gelatinization temperatures of cassava starch were determined at various starch moisture contents. To investigate phase transition of cassava starch, cassava starch was dried using pilot-scale pneumatic conveying dryer. Temperature, moisture content and particle size distribution of cassava starch were measured along the drying tube. Experimental results showed that at the early stage of drying process, the temperature of cassava starch was higher than its glass transition temperature indicating that the starch was in rubbery phase. After the starch passed the middle stage of drying tube, the phase changed from rubbery to glassy state. This phase transition of the cassava starch correlated with the changes of particle size. The agglomeration of the cassava starch occurred when the cassava starch was in rubbery phase.