Temperature-Dependent Dielectric Properties of Selected Subtropical and Tropical Fruits and Associated Insect Pests

Wang, S.; Monzón, Maria E.; Gazit, Yoav; Tang, Juming; Mitcham, Elizabeth; Armstrong, J. W.

doi:10.13031/2013.19985

Cited by 76 publications

(53 citation statements)

References 24 publications

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“…7), suggesting the increasingly important role of dipole water molecules. This is in general agreement with observations made by Guan et al (2004) for mashed potato containing 1.3% or more salt and by Wang et al (2005) for subtropical and tropical fruits.…”

Section: Effect Of Ionic Conductivity On Loss Factorsupporting

confidence: 92%

“…A custom built temperature test cell (Wang et al, 2003b;Wang et al, 2005) connected to an oil bath (PolyScience Products, Niles, Ill., USA) was used to control sample temperature during dielectric property measurement. The system was calibrated before each independent measurement to avoid possible variations in the connections, ambient temperature and other factors that might affect the system performance.…”

Section: Experimental Set Up and Dielectric Properties Measurementmentioning

confidence: 99%

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Dielectric properties of salmon fillets as a function of temperature and composition

Wang

Tang

Rasco

et al. 2008

Journal of Food Engineering

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Section: Effect Of Ionic Conductivity On Loss Factorsupporting

confidence: 92%

Section: Experimental Set Up and Dielectric Properties Measurementmentioning

confidence: 99%

Dielectric properties of salmon fillets as a function of temperature and composition

Wang

Tang

Rasco

et al. 2008

Journal of Food Engineering

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“…The technique is not suitable for determining permittivities of granular and pulverized samples when bulk densities of such samples were established by auxiliary permittivity measurements. This method is convenient, relatively easy to use because of its ability to scan through a wide range of frequencies with desired accuracy and little or no sample preparation (Feng et al 2002;Ikediala et al 2000;Nelson 2003;Venkatesh and Raghavan 2004;Wang et al 2003Wang et al , 2005.…”

Section: Open Ended Coaxial Probe Techniquementioning

confidence: 99%

Measurement techniques and application of electrical properties for nondestructive quality evaluation of foods—a review

et al. 2011

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Non-destructive systems are recent trends for quality evaluation of fruits and vegetables. Information on post-harvest variations in electrical properties is needed to develop new instruments for this purpose. Electrical properties are finding increasing application in agriculture and food processing industries. Knowledge of dielectric properties of foods as a function of moisture content and temperature is essential in the design and control of drying systems. As simple, rapid and non-destructive measuring techniques, dielectric spectroscopy provides information about the dielectric response of materials to electromagnetic field. Electrical properties of agricultural materials have been of interest for many years. The interest in dielectric properties of materials has historically been associated with the design of electrical equipment. This review paper covers theoretical aspects of different electrical properties, their measurement techniques, applications of dielectric properties in agriculture/food processing sector and potential applications of thermal imaging (TI) for quality and safety assessment in food processing. The values of dielectric properties of a number of products including food grains, fruits and vegetables, and meat and meat products are presented in table form. This comprehensive coverage will be useful for academic, scientific and industrial community in treating and applying the facts in developing/testing new processes and products based on electromagnetic energy application.Keywords Electrical properties . Non-destructive . Measuring techniques . Dielectric constant . Loss factor . Thermal imaging technique . Food quality evaluationThe material investigation and moisture measurement using electromagnetic waves in wide spectrum serve for quality control and improvement in many branches like industry, forest and wood-working industry, civil engineering, agriculture, commerce and also foods e.g. for quality evaluation of meat, fruits, coffee etc (Hlavacova 2003; Venkatesh and Raghavan 2004). Non-destructive evaluation of quality based on constituents of fruits and vegetables has been successfully used (Chen et al. 1999;Jha et al. 2001;Kawano 1998). Electrical characteristics of agricultural materials have been of interest for many years (Nelson 2006) and are utilized in many areas of human activities. Techniques for non-destructive determination of quality and related characteristics of agricultural products are helpful to producers, handlers and processors . Permittivity and moisture can be closely correlated when water content is high. Knowledge of dielectric properties in partially frozen material is critical in determining the rates and uniformity of heating in microwave thawing. Electrical properties are important in processing foods with pulsed electric fields, ohmic heating, induction heating, radio frequency, and microwave heating. These properties are also useful in the detection of processing conditions or the quality of foods (Barbosa-Canovas et al. 2006). Considering ...

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“…Some interesting findings have been reported towards the RF and microwave treatments of fruits, and nuts [14]. Dielectric behaviour of the fruit flies, medfly (egg and larvae), melon fly, Mexican and oriental flies was investigated at frequencies between 1 MHz and 1.8 GHz, and the temperatures between 20 and 60 • C. They concluded that the ionic conduction dominated the dielectric behavior in the RF range, and due to the same magnitude of the ε of the subtropical and tropical fruits and the insects, the differential heating of insects in these fruits is not possible when they are treated together in an RF system.…”

Section: Introductionmentioning

confidence: 96%

Elimination of Cruptolestes Ferrungineus S. In Wheat by Radio Frequency Dielectric Heating at Different Moisture Contents

Shrestha

Yu²,

Baik³

2013

PIER

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Abstract-Radio frequency (RF) dielectric heating was tested to control Cryptolestes ferrungineus S. in the bulk wheat samples (ca.152 g, dia. = 50 mm, ht. = 100 mm) at the MCs (%, w. b.) of 12, 15, and 18 using a pilot-scale RF heater (1.5 kW, 27.12 MHz) in the batch mode. When the temperature of the hottest spot (geometric center) of the sample, T H was at 80 • C, all the adult insects were found dead at the cold spots, near bottom-wall, at 50.7 to 56.0 • C depending up on the wheat MCs. The temperatures of the insectslurries higher than that of the bulk wheat by 0.8 to 15.1 • C indicated the selective heating of the insects. The mortalities of adult insects were almost constant within the quarantine period, QP1 (5 wk). The elapsed time during QP1 had a significant effect only on the insects' mortalities with the wheat at 12% MC. The wheat MC had only marginal significance on the absolute mortalities of insects. The larvae were completely destroyed at temperatures between 55 and 60 • C. The complete mortality of all life stages (eggs, larvae, pupae, and adults) of the insect was achieved at T H = 80 • C without any emergence of the insects during QP2 (8 wk). The RF treatment enhanced the germination of the wheat kernels at 12% MC while it was decreased by 2 to 33% depending up on the wheat MC, and the treatment temperature. Temperature had no significant effect on the falling numbers, and the yields of flour, bran, and shorts, and the peak bandwidth and the MC of the wheat, and the flour protein values. The means of the mixing-development-time deferred from the controls mostly for the wheat at 15% MC and T H = 70 • C, and 18% MC and T H = 70 and 80 • C. The mean-peakheight and the color values varied between 4 and 16%, and 3 and 6% off the controls depending up on the temperatures. The uniform temperature of 60 • C should be enough 518Shrestha, Yu, and Baik to control all life stages of the insect completely with a little or no changes in the important product qualities and germination of the wheat at MCs safe for the storage. Future research mainly focused on better estimation of the insect-to-grain electric field intensities is essential.

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Temperature-Dependent Dielectric Properties of Selected Subtropical and Tropical Fruits and Associated Insect Pests

Abstract: ABSTRACT. Knowledge of the dielectric properties of commodities and insect pests is important in developing thermal

Cited by 76 publications

References 24 publications

Dielectric properties of salmon fillets as a function of temperature and composition

Dielectric properties of salmon fillets as a function of temperature and composition

Measurement techniques and application of electrical properties for nondestructive quality evaluation of foods—a review

Elimination of Cruptolestes Ferrungineus S. In Wheat by Radio Frequency Dielectric Heating at Different Moisture Contents

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