Disinfestation of Weevil's Eggs in Organic Rice with Microwave Heating

Abstract

Production of organic rice is restricted to the use of insecticides and other chemical compounds;therefore this product is at higher risk of infestation of rice weevil (Sitophilus oryzae L.). The damagecaused by this insect is not acceptable for consumers. The objective of this project was, therefore, to studythe effects of microwave power and process time to the mortality of rice weevil,s eggs in organic rice andof the rice qualities. The samples were infested and treated with microwave under different power levelsand heating times. The microwave power levels used in this study were 0.41, 0.51 and 0.64 kW; and theheating times were 20, 30 and 40 s. It was found that the weevil,s eggs were completely disinfested whenthe temperature of rice increased beyond the critical temperature of 55 degree Celsius. Using microwavepower at 0.64 kW required only 30 s to complete the disinfestation process; whereas, heating rice withmicrowave power at 0.41 kW and 0.51 kW required longer process time of 40s. Heating rice for 20s withall microwave levels could not completely disinfest weevil,s eggs because the rice temperature was lowerthan the critical temperature. Employing of microwave heating in weevill,s eggs disinfestation had nosignificant effect on rice qualities: i.e., moisture, color, fat and protein contents; but on fracturing ratio dueto the rapid temperature elevation. It is possible to use microwave treatment for weevil,s eggs disinfestationin organic rice production.

Keywords: Organic Rice / Weevil,s Eggs / Microwave