A dielectric technique based on a one-chip network analyser to predict the quality indices of shell eggs

The present study investigates the possibility of predicting the main quality indices of shell eggs by means of a dielectric technique based on a capacitor probe and a fully integrated RF circuit for measuring the amplitude and phase differences between two independent input signals. Samples of eggs were submitted to dielectric measurements in the range 50–500MHz after 1, 2, 4, 8, and 15 days of storage at room temperature (20 °C). Immediately after testing, the air cell and the thick albumen heights, the Haugh unit and the yolk index of eggs were destructively measured. Statistical models obtained by processing dielectric spectra and quality indices determined by means of partial least square (PLS) analysis showed coefficients of determination (R^2) values up to 0.996 for the time of storage, 0.876 for the air cell height, and 0.678 for the thick albumen height. Accurate predictions were also obtained for models based on selected narrow spectral regions.