Relationship of Pears’ Dielectric Properties and Rates of Pears’ Bruise

Abstract

Nowadays, dielectric materials, as one of the nondestructive methods, have drawn the researchers’ attention to their diverse array of advantages to the other methods. Before loading and storage, 120 pears were examined under CT-Scan and 81 pears with zero bruise were selected followed by subjecting them to quasi-static and dynamic loading and a 10 day storage period was chosen to investigate the bruise levels and their relationships with dielectric constant. At the end of the storage period, the fruits were measured in their dielectric constant after their bruise levels were determined in CT-Scans. The measurements were undertaken in capacitor plate distances of 8, 11 and 14 cm for input voltages of 6, 10 and 14 V and input voltage frequencies of 20, 60 and 100 KHz for two fruit placement directions. The results showed that the highest dielectric constant, 5.4868, belonged to broad-edge compressive plate for a plate capacitor distance of 8cm and subject to a 130N loading and a bruise level equal to 39.563; moreover, the lowest dielectric constant, 5.01651, was found belonging to longitudinal placement direction and subject to a 350 g loading weight exerted in the form of impact for a decay level equal to 5.147. The final result was that the bruise level increases and moisture content decrease with the elevation of the compression force following which the dielectric constant demonstrates higher values.