Electric properties of apple purée and pulpy apple juices

Abstract

Results are presented of research, the aim of which has been to determine the selected physicochemical qualities, including electric quantities, of apple purées and pulpy juices obtained from them. The characteristics of the electric properties have covered the measurements of impedance (Z) and effective resistance (R), admittance (Y) and conductance (G), as well as equivalent parallel capacitance (Cp) and equivalent series capacitance (Cs). Changes have been determined in the purée properties relating to the technology of production as well as the function of diluting and the storage period. Apple purées, depending on the production technology, are characterized by the diversified, characteristic ranges of the resistivity and conductivity values. As the degree of the purée dilution rises, conductivity of juices falls. These relationships remain true throughout the purée storage period. In the conditions of the experiment, the measured values of resistivity and conductivity of pulpy juices clearly determine the content of apple purées in juices.

Correlations between selected quality and electrical parameters of musts from stone and pome fruits

“…Impedance measurements may also prove well in the assessment of moisture content during the heating and drying of potato tubers and carrot roots, and in the detection of artificial chemical additives in liquid food products [18][19][20]. The results of our own studies showed that measurements of electrical parameters (impedance, resistance, admittance, and conductance) may be applied to assess apple puree concentrations in pulpy juices and beverages [2,21], to determine contents of Total Soluble Solids (TSS) in reconstituted apple juices [22], and to determine contents of mineral substances, ash, and dry matter in apple juice [8].…”

“…These products owe this special role to their biologically-active compounds. From the nutritional perspective, naturally cloudy juices-purees and musts, represent significantly richer sources of bioactive compounds compared to the clear juices due to particles of fruit pulp they contain [1,2]. Significant complexity and time-consumption of methods used to evaluate technological parameters of food products as well as the need for automation of production processes have contributed to a growing interest of scientists in novel methods whose food quality prediction precision would be close to the precision of methods used for direct quality measurement.…”

Studies on determination of mathematical relationships between rapeseed oil content and electrical properties of butter and fat mixes

“…2. Scheme of a measuring system of electrical properties of raw materials and food products: Z -impedance, R -resistance, C s -series equivalent capacitance, C pparallel equivalent capacitance, M -measuring device (Pierzynowska-Korniak et al, 2003;_ Zywica et al, 2005). measured parameters in the function of frequency were observed for butter and the greatest for oil, respectively.…”

“…2) elaborated by our research group based on our previous studies with: milk, fruit juices and fruit purée, and meat(Pierzynowska-Korniak et al, 2003;_ Zywica et al, 2005;Banach and _ Zywica, 2010;_ Zywica et al, 2012), but also based on results of investigations published in available research works(Mabrook and Petty, 2003a,b).…”

Influence of Variety, Moisture Content, Kernel Size and Applied Current Frequency on the Electric Properties of Wheat Grain

“…Measurements were repeated 6 times according to the electric model previously described. [16,17] Next, on the basis of the measurements obtained, specific: impedance (Z sp ), resistance (R sp ), admittance (Y sp ) and conductance (G sp ) were calculated using formulas 4-7: [17] where: l is distance between the electrodes (m), and s is active surface of electrodes (m 2 ). The results of investigations were statistically analyzed using the Statistica™ 6.1 programme.…”