Terahertz Sensing for Fruit Spoilage Monitoring

A novel method was presented in this paper to obtain the absorption coefficient of pear and apple slices based on the scattering parameters, which were measured by employing Vector Network Analyzer (VNA) extended into the Terahertz (THz) frequency range of 0.75 THz to 1.1 THz with Swissto 12 waveguide systems. The results show the significant difference of absorption coefficient and transmission response between pear and apple slices when the Moisture Content (MC) value is less than 50% with the passing days. The comparison results display that the decreasing ratio of the absorption with the MC in apple slice is nearly three times faster than that in pear slice due to the different characteristics of the internal constituents and texture structures in the THz region. The application presented in this paper can be applied to detect the chemical characteristics and the signatures of inner compositions for quality control in fruits.