Infrared heating as a disinfestation method against Sitophilus oryzae and its effect on textural and cooking properties of milled rice

Infrared (IR) heating method against rice weevils (Sitophilus oryzae) in an egg stage was investigated. A kinetic model was developed to describe insect mortality in a temperature range of 40-60 A degrees C. Effects of IR heating temperature (50-60 A degrees C) and exposure time (1-3 min) on insect mortality and quality attributes of the treated rice were evaluated. The optimized condition obtained by means of the response surface method was used to analyze rice quality before and after IR treatment with storage. The results showed that the 0.5th-order thermal death kinetic equation was the most suitable model, and the S. oryzae eggs had less heat tolerance than the adults and some other species. Mortality achieved 100 % after 2 min for all temperatures. Both IR heating parameters significantly affected the treated milled rice qualities. The minimal changes in rice quality before and after storage could be obtained using optimized temperature and exposure time of 53.6 A degrees C and 1.2 min, respectively