Relationship between moisture content and electrical impedance of carrot slices during drying

Abstract

A b s t r a c t. Electrical properties of food materials can give information about the inner structure and physiological state of biological tissues. Generally, the process of drying of fruits and vegetables is followed by weight loss. The aim of this study was to measure the impedance spectra of carrot slices during drying and to correlate impedance parameters to moisture content in different drying periods. Cylindrical slices were cut out from the carrot root along the axis. The slices were dried in a Venticell 111 air oven at 50°C. The weight of the slices was measured with a Denver SI-603 electronic analytical and precision balance. The weighing of the samples was performed every 30 min at the beginning of drying and every 60 min after the process. The moisture content of the samples was calculated on wet basis. The magnitude and phase angle of electrical impedance of the slices were measured with HP 4284A and 4285A precision LCR meters in the frequency range from 30 Hz to 1 MHz and from 75 kHz to 30 MHz, respectively, at voltage 1 V. The impedance measurement was performed after weighting. The change in the magnitude of impedance during drying showed a good correlation with the change in the moisture content.

Electrical Impedance Spectroscopy for Quality Assessment of Meat and Fish: A Review on Basic Principles, Measurement Methods, and Recent Advances

“…According to the biological objects, application of EIS can be divided into three aspects, that is, electrical impedance tomography in medical imaging [2][3][4], quality and safety assessment in food industry, and phytophysiology in agronomy [5][6][7]. Research objects and targets of EIS applied in food are abundant and extensive, including for fruits, such as study on dry matter content of durian [8] and ripening of banana [9], for vegetables, such as changes in potato and spinach tissues during or after heating [10,11] and moisture content of carrot slices during drying [12], for meat, such as quality evaluation of pork meat during storage [13] and investigation of beef meat behavior during ageing [14], for chicken, such as discrimination of fresh and frozen-thawed chicken breast muscles [15], for fish, such as salt and moisture content determination of salted rainbow trout [16] and freshness estimation of carp [17], for dairy products, such as real-time detection of bovine milk adulteration [18], and moreover for determination of the additives content in natural juices [19], fermentation process of bread dough [20], and quality assessment of cooking oil [21]. Nowadays customers pay more attentions on quality attributes of meat products, such as appearance, flavor, and nutrients.…”

Mechanical properties of sugar beet root during storage

“…The mechanical properties of the beet, together with sucrose, soluble solids and moisture content, are important parameters in evaluating the sucrose yield and the cost of sugar beet production, and also for assessing new sugar beet germplasms and/or cultivars (Cheng et al, 2011;Kabas and Ozmerzi, 2008;Kertész et al, 2015;Kumbár et al, 2015). Most of these properties are evaluated through compression, rheological and puncture testing (Sirisomboon et al, 2012;Szymanek, 2009;Trávníček et al, 2016;Trnka et al, 2016).…”

Model of dehydration and assessment of moisture content on onion using EIS

“…The experimental results of the moisture content of material undergoing microwave drying were in congruence with the predictions of the proposed model (Hemis et al 2012 ). Kertesz et al ( 2015 ) utilized EIS to measure electrical response of carrot slice during drying by HP 4284A and 4285A precision LCR meters in the frequency range from 30 Hz to 1 MHz and from 75 kHz to 30 MHz, respectively, at a voltage of 1 V. By measuring the weight of the samples with a with a DenverSI-603 electronic analytical and precision balance, the moisture content was calculated on wet basis. Moisture content was found to decrease according to a polynomial function and alteration of impedance during drying showed good correlation with change in moisture content.…”