An attempt of applying the electrical properties for the evaluation of milk fat content of raw milk Original Research Article

This manuscript presents outcomes of a study aimed at determining a correlation between milk fat content as the key indicator of raw milk quality and the conductance and capacitance properties of milk. The analysis of correlation and linear regression of fat content (F) in the function of changes in impedance (Z), admittance (Y), parallel equivalent capacitance (Cp) and series equivalent capacitance (Cs) of milk demonstrated that within a frequency range of 100 Hz to 100 kHz, correlations were observed that could be described with the following equation: y = ax ± b. The highest correlations (0.934 ⩽ r ⩽ 0.990; α = 0.006 – 0.000) were achieved between fat content of raw milk and values of the parallel equivalent capacitance (Cp). This means that the most accurate determination of fat content (F) of raw milk is feasible through the measurements of Cp and calculations based on mathematical equations, e.g. F = a × Cp + b. The correlations achieved in the measuring voltage frequency range of 100 Hz to 100 kHz encourage to continue investigations aimed at developing a rapid method for the assessment of fat content of raw milk based on measurements of electric parameters of conductance and capacitance.