Predicting quality parameters of shell eggs using a simple technique based on the dielectric properties

A sinewave radio frequency oscillator with parallel plates capacitor sample probe was used to measure the differences in capacitance DC and voltage DV caused by the introduction of a shell egg into the probe. Eggs were submitted to measurement after laying and after 3, 6, 9, and 12 days of storage at 20°C. The results show a significant difference of the DC/DV ratio during storage; this parameter was correlated with all the quality indices of the eggs such as the storage duration, air cell height, yolk index, albumen height, and Haugh unit. Using multiple linear regression models with the DC/DV and egg mass parameters as predictive variables, adjusted coefficients of determination from 0.310 to 0.595 were obtained. The DC/DV electrical parameter in these equations was always characterised by a probability level <0.0001. The use of non-linear instead of linear regressions did not involve substantial differences in the prediction power of the equations. Performing broken linear regression with the same predictive parameters, values of the coefficients of determination from 0.640 to 0.850 were obtained.