Dielectric properties of papaya seeds from 75 kHz to 5 MHz
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State University of Northern Rio de Janeiro – UENF, Agricultural Engineering Department, Av. Alberto Lamego 2000, 28013-602 Campos dos Goytacazes, Brazil
Brazilian Federal Institute of Education, Science and Technology, 29300-970 Cachoeiro de Itapemirim, Brazil
Department of Bioscience and Biotechnology – UENF, 28013-602, Brazil
Federal University of Rio de Janeiro – UFF, Department of Agribusiness, 27255-125, Volta Redonda, Brazil
Pedro A. Berbert
Publish date: 2019-05-16
Acceptance date: 2018-12-18
Int. Agrophys. 2019, 33(2): 185–192
The object of this work was to study the dielectric properties of papaya seeds of the Golden cultivar and seeds of two papaya hybrids, Tainung and Calimosa, in the frequency range from 75 kHz to 5 MHz at four levels of bulk density, and with moisture contents ranging from 6 to 23% wet basis. The relative permittivity and the loss factor of the seeds were measured using a precision LCR meter, and their relationship with the variable frequency of the oscillating electric field, the seed moisture content and bulk density, and the cultivar/hybrid type were established. Relative permittivity for each value of the moisture content was reduced regularly as the frequency increased. Abrupt changes in the slopes of the curves demonstrating the relationship between the relative permittivity and the loss factor, and the moisture content were considered an indication of changes in the water sorption mechanisms occurring within the seed. The relationship between the relative permittivity and the loss factor, and bulk density was represented by linear functions with positive slopes. The effect of the cultivar or hybrid types on the relative permittivity and the loss factor revealed that seeds of the Golden cultivar and the Tainung hybrid exhibited similar relative permittivity values in the whole frequency range studied, in contrast to seeds of the Calimosa hybrid.
Thanks are due to Caliman Agrícola S.A. which provided all the fruit lots used in this experiment. We would like to acknowledge the contribution of Mr Pedro Henrique Dias for the collection of fruits.
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