Electrical properties of maize kernels contaminated with aflatoxin

Abstract

The purpose of this study was to investigate the effect of aflatoxin contamination on the dielectric constant of maize kernels. A factorial experiment comprising of three levels of moisture content (13.3%, 15.3%, and 16.4%), three frequencies (25, 50, and 100 kHz), and nine levels of aflatoxin contamination (0, 1.5, 2.6, 10, 50, 100, 150, 172, and 230 μg kg-1) was used. The maize kernels were poured into a custom-built sample holder comprising a shielded parallel plate capacitor. An ISO-TECH LCR-821 meter was used to measure the capacitance, from which the dielectric constant was computed. The results indicated that moisture content and frequency significantly (p≤0.05) affected the dielectric constant. The dielectric constant increased with increase in moisture content and decreased with increasing frequency. However, aflatoxin contamination level had no significant (p>0.05) effect on the dielectric constant of maize kernels. The coefficient of determination (R2) of dielectric constant and aflatoxin contamination levels was low (R2 = 0.2687), indicating a poor correlation between the aflatoxin levels and the dielectric constant of maize kernels. Based on the findings, the dielectric constant is unsuitable for predicting the level of aflatoxin contamination in maize kernels within the 20-200 kHz frequency range.