Microwave Application for Controlling Oryzaephilus surinamensis Insects Infesting Dried Figs and Evaluation of Product Color Changes Using an Image Processing Technique

Abstract

In this study, microwave heating was employed for controlling Oryzaephilus surinamensis adult beetles infesting stored Iranian dried figs. The dried fig samples were artificially infested with O. surinamensis and then heated in a microwave oven (2,450 MHz) at power outputs of 450, 720, and 900 W for 20, 30, 40, and 50 s. Changes in the color of the samples after these microwave applications were evaluated for lightness (ΔL*), redness (Δa*), and yellowness (Δb*) using an image processing technique. Both parameters of microwave power and exposure time had significant effects on beetle mortality (P < 0.01). A direct positive relationship was found between the mortality rate and microwave power. Complete mortality was achieved at 900 W and for 50 s. The color parameters of the dried fig samples did not change significantly. These results indicate that microwave irradiation can be introduced as an appropriate alternative to chemical fumigants without affecting product quality.

High-Pressure Carbon Dioxide Use to Control Dried Apricot Pests, Tribolium castaneum and Rhyzopertha dominica, and Assessing the Qualitative Traits of Dried Pieces of Treated Apricot

“…It was done by using a white fluorescent lamp mounted under the ceiling of our special chamber, the walls of which were covered with a black cover. Photographing was performed at a distance of 30 cm from the specimens put against a white background [22]. The images were captured at 959 pixels × 1280 pixels and a resolution of 96 dpi in Jpeg format and RGB color space.…”

“…In the image processing technique, the parameters of L*, a*, and b* indicate brightness, redness, and yellowness of products, respectively, which can be changed in the treatments by pest control and preserving agents [21]. For example, Sadeghi et al [22] reported increasing L*, a*, and b* variations for figs and raisins with enhancing microwave powers and timings in the sawtoothed grain beetle (Oryzaephilus surinamensis L.) management. Additionally, Inserra et al [23] observed an increase in L* and b* and a reduction in a* parameters of apricots treated with sulfur before drying.…”