1976 Volume 23 Issue 7 Pages 283-287
Experiments on the radiation disinfestation of rice and the organoleptic evaluation of rice irradiated by the silo type grain irradiator were conducted. This irradiator was designed as a pilot scale to obtain the data for the industrial grain irradiator. The irradiator has the Co-60 rod source of 2771 Ci in the center tube and three annular cylindrical irradiation fields around the source. The radiation dose is controlled by regulating the shutting time and slit width of the annulus gate valves.
In the disinfestation test, the adults, eggs, larvae and pupae of rice weevil, Sitophilus zeamais, which is one of the main cereal insects in Japan, were irradiated with the rice at the dose of 8-21 krad. The mortality of adults was about 85% at 7 days after irradiation and almost 100% at 21 days. The emergence of adult from eggs, larvae and pupae was also prevented by irradiation. The organoleptic properties in appearance, odor, taste, cohesiveness, hardness and over-all were evaluated by comparing non-irradiated rice with irradiated one. A slight organoleptic deterioration of cohesiveness was detected on the irradiated sample immediately after irradiation. But there are no significant differences on the sample stored for 3 months after irradiation.
