Computer simulation analyses to improve radio frequency (RF) heating uniformity in dried fruits for insect control

In this study, an experimentally validated computer simulation model was developed to predict the effects of different package geometries, electrode configurations, and use of forced air (60°C) on improving the heating uniformity of raisins treated with RF for insect control. Higher temperatures (60–76°C) were observed in the areas between the edges and corners on the top and bottom layers of the RF treated raisins held in rectangular and cylinder shaped containers, with lower temperatures (40–52°C) observed in the central areas of each layer. The heating uniformity was improved by rounding the corners of the containers and reducing sharp edges on the packages, modifying electrode configurations, and applying forced air after RF heating. These modifications reduced the maximum temperature difference throughout a container of heated raisins to about 5°C. Approximately 356min were needed to raise the raisin temperature in a rectangular container from 23°C to 55–60°C using only forced air at 60°C. In contrast, only 6min of RF heating followed by 10min of forced air treatment at 60°C was needed for a similar filled container to reach a temperature of 55–60°C. Shortening the electrodes length to 4cm shorter than the horizontal dimensions of the rectangular containers also improved heating uniformity. This technique can be easily implemented to improve the uniformity of RF heating in the food industry for the control of insects in packaged dried fruits. Industrial...
Source: Innovative Food Science and Emerging Technologies - Category: Food Science Source Type: research