Abstract
Irradiation effect on digestion of raw starch by glucoamylase has been investigated as a basic research for application of radiosterilization on uncooked starch fermentation. The digestibility of raw tapioca starch decreased with an increase in dose while that of other starches such as wheat, corn, sweet potato and potato were little changed by irradiation. Tapioca starch granules coagulated by irradiation and were sedimented rapidly in suspension. The coagulation of irradiated tapioca starch granules can be dispersed completely by ultrasonic treatment. These results show that the decrease in digestion of raw tapioca starch depends on the coagulation of starch granules but other factors also contribute because the recovery of digestibility by ultrasonic treatment was not complete.