Microwave Use in the Control of Ephestia kuehniella (Lepidoptera: Pyralidae) in Dried Fig and Raisin and Effects on Fruit Sensory Characteristics

Abstract

Microwave heating is an environmentally friendly method for killing pest insects and here its efficacy in the control of a pest species of dried fig and raisin was assessed. Dried fig and raisin samples were infested with Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) larvae and heated in a microwave oven at power outputs of 450, 720, and 900 W for 20, 30, 40, and 50 s. Following exposure to the microwave treatments, larval mortality and changes to organoleptic properties, which indicate consumer preference and include aroma, color, sweetness, acerbity, fragility, stiffness, and overall acceptability, were assessed. Our results showed mortality rates were greatest with the highest degree and duration of microwave exposure, where 100% mortality was recorded at 900 W with an exposure time of 50 s. The sensory evaluations of the fruit showed that microwave heating had some effect on aroma, color, fragility, sweetness, and overall acceptability, but no effect on acerbity and stiffness in dried fig, whereas in raisin, there were no impacts on acerbity, stiffness, or sweetness, but aroma, color, fragility, and overall acceptability were affected. We conclude that application of lower intensities of microwave treatment may provide acceptable levels of pest control in stored dried fruit without an associated trade-off in the reduction in quality of sensory attributes.

Physical assessments of termites (Termitidae) under 2.45 GHz microwave irradiation

“…Owing to the low heat conductivity of wood, the heating of its interior is relatively time intensive. However, in the treatment of agricultural products, pest insects generally die in much shorter time frame 2,29 . It may be possible that factors other than temperature increase insect death.…”

Individual and combined effects of contact insecticides and high temperatures on Mediterranean flour moth,Ephestia kuehniellaZeller (Lepidoptera: Pyralidae)

“…In recent years several studies have been conducted to assess the susceptibility of stored‐product pests to heat treatments. Results of these studies demonstrated that the ability of insects to survive at high temperatures varies among pest species and life stages, and is influenced by temperature, exposure time and relative humidity 12‐15 . The effect of dry heat treatment on the characteristics of wheat flour and bread has also been studied in several studies.…”

“…Mediterranean flour moth or mill moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) is a common pest of cereals and flour throughout the world 22 . This pest also causes significant losses in the quality and market value of dried fruits such as raisins and dried figs and dates in Iran 14 . It is frequently found in warm places such as flour mills and bakeries.…”

“…The effects of high temperatures on larval stage of Mediterranean flour moth have been assessed in a few studies. Sadeghi et al 14 . assessed the effects of microwave heating on E. kuehniella larval mortality and organoleptic features of dried figs and raisins.…”

The effects of power ‐ ultrasound, peroxyacetic acid and sodium chloride washing treatments on the physical and chemical quality characteristics of dried figs

“…The dried fig is distinctly nutritious with high mineral, carbohydrate, dietary fiber, essential amino acid, vitamin and polyphenol contents, while being fat and cholesterol free (Aksu Demirezen et al., 2019; Benalia et al., 2016; Khadhraoui et al., 2019). Numerous studies have been demonstrated the health‐promoting effects of dried figs (Arvaniti et al., 2019; Chang et al., 2016; Pourghayoumi et al., 2016; Sadeghi et al., 2018; Vallejo et al., 2012). Dried fig is a rich source of bioactive compounds possessing a positive impact on the prevention of cardiovascular, respiratory and inflammatory diseases (Ansari et al., 2015; Turan & Celik, 2016).…”