Abstract
In Spain, citrus industry is one of the main economic sectors representing a total production of 5.567.672 tons in 2012 according to the Ministry of Agriculture, Food and Environment. The main citrus fruits produced in the country are sweet orange, mandarin and lemon. It is important to highlight that the Valencian Community represents 90% of the total production of mandarins (Ministry of Agriculture, Food and Environment). Currently, citrus industry is subject of constant technological improvement in order to face an increasingly, globalized and demanding market regarding to the quality of the products. Therefore, this investigation consists on the study of viability of the dielectric properties as a non-destructive technique to determine the quality of mandarins. In this context, the study and analysis of the dielectric spectrum of the different mandarin tissue and together with physical, chemical and microstructural measurements such as aw, xw, pH, maturity index (ºBrix and titrable acidity) and Cryo-SEM will let to understand the dielectric behaviour of each tissue. The dielectric measurements in the range of the electromagnetic spectrum of the radio frequency (RF) were made with an Agilent 16451B parallel plate fixture connected to an Agilent 4294A impedance analyser from 40 Hz to 1 MHz and in the microwave range (MW) with an Agilent 85070E open-ended coaxial probe connected to an Agilent E8362B Vector Network Analyser from 500 MHz to 20 GHz. It has been possible to describe the different dispersions from chemical and physical measurements developing a tissue discrimination system which introduce the opportunity to develop the description and conformational tissues systems in a microstructural level as a nondestructive method.
