Abstract: This study analyzed the effects of radio frequency-hot air treatment under different conditions of initial corn moisture content (19.05%, 22.25%, and 25.55%), radio frequency heating temperature (55, 65, 75, and 85 ℃) and heating time (10, 15, 20, and 25 min) on the degradation of aflatoxin B1 (AFB1) and corn quality. The results showed that radio frequency-hot air treatment could effectively degrade AFB1. For corn with high initial water content, at the same heating temperature and time, higher initial moisture content resulted in higher residual amount of AFB1. At the same initial water content, the residual amount of AFB1 decreased with the increase in heating temperature and time. Heating time had a greater effect on AFB1 degradation than temperature. Radio frequency-hot air treatment affected corn quality. With increasing heating temperature and time, neither protein nor fat contents significantly changed compared with the control group (P > 0.05), while viscosity significantly decreased (P < 0.05). Low-field nuclear magnetic resonance (NMR) analysis showed marked changes in water mobility during radio frequency heating, and water mobility characteristics were significantly correlated with the gelatinization characteristics, protein, and fat contents of corn (P < 0.05).

Key words: aflatoxin B1; radio frequency-hot air drying; corn quality; low-field nuclear magnetic resonance; corn kernels