Possibilities of Using Electrical Parameters of Milk for Assessing its Adulteration with Water

Abstract

This manuscript presents results of a research aimed at conducting a statistical analysis of correlation between the percentage addition of water to milk and its electrical parameters, which are used to determine the degree of milk dilution and the level of milk adulteration with water. The results of milk conductivity parameters analysed in the study showed admittance and conductance to decrease systematically with water addition from ca. 10.8 to 7.8 mS. In contrast, impedance and resistance values were observed to increase from ca. 91 to 128 Ω. Results of the measurements of capacitance parameters showed that with an increasing content of distilled water in milk the value of equivalent parallel capacitance was decreasing from 1.4 to 0.65 μF. In turn, along with water content increasing to 15%, the value of equivalent series capacitance was increased from 212 to 237 μF. Still, at water content of milk exceeding 15%, the value of that parameter remained unchanged. The statistical analysis demonstrated a close linear correlation (0.989 ≤ r ≤ 0.998) between the percentage of water added to the milk and electrical parameters of impedance, resistance, admittance, conductance, as well as equivalent parallel capacitance of milk.