Efficient removal of aflatoxin B1 from soybean kernels by a coupled ultrasound–ozone process: A mechanistic study

Aflatoxin B1 (AFB1) contamination in soybean kernels poses a persistent food safety challenge. This study evaluated the coupled ultrasound–ozone (US/O 3 ) process for AFB1 removal from soybean kernels. After 10 min of treatment, the US/O 3 process removed 96.2 % of AFB1, far exceeding ozone alone (54.5 %), ultrasound alone (36.9 %), and water washing (18.1 %). Mass balance analysis showed that only 10.4 % of the initial AFB1 remained in the kernels and soaking water after US/O 3 treatment, indicating that the process mainly destroyed AFB1 rather than merely transferring it into the liquid phase. A positive, time-dependent synergy factor quantified the cooperative effect between ultrasound and ozone. Electron spin resonance (ESR) spin-trapping combined with radical scavenging experiments identified hydroxyl radicals (HO • ) as the dominant oxidants. Identified transformation products suggested an initial attack on the terminal furan ring, followed by extensive hydroxylation, ring opening, dealkylation, and fragmentation to low-molecular-weight phenolic products. ECOSAR predictions showed higher LC 50 values for most products than for AFB1, indicating reduced acute toxicity. Fourier transform infrared (FTIR) spectra, color parameters, and lipid oxidation indices indicated negligible changes in soybean composition and quality. Therefore, the US/O 3 process offers an efficient, quality-preserving strategy for mitigating AFB1 contamination in soybean kernels.