Nondestructive imaging of the sugar distribution inside a fruit by use of CP-MCT

Originally, chirp pulse microwave computed tomography (CP-MCT) was developed for noninvasive imaging of a human body. The tomographic image provides not only the permittivity distribution of the cross section but also various physical- or chemical-quantities relating to the permittivity value such as temperature and salt concentration. Generally speaking, fruits are dielectric materials containing much water, sugar, acids and so on. Accordingly, the quantities which vary the permittivity value such as sugar content, acid content and etceteras are visualized by microwave imaging. By use of the high-resolution model of CP-MCT using the chirp pulse microwave signal from 2 GHz to 3 GHz, nondestructive imaging of sugar content inside fruits is worthy to be investigated. In this study, we have confirmed that the sugar distribution inside the Japanese pairs vary according to the harvest time.