Enhanced removal of aflatoxins from soybean kernels by the coupled ultrasound-chlorination process: efficiency and...

Aflatoxin contamination in soybeans is challenging because toxins can partition into dense kernel matrices. This study developed a coupled ultrasound-chlorination (US/Cl) process to remove four aflatoxins from soybean kernels. Within 10 min, US/Cl achieved 80.4-91.3% removal, outperforming chlorination alone (45.3-57.2%) and ultrasound alone (38.4-40.2%). The synergy factor increased from 0.1 to 1.9% (2 min) to 15.0-19.8% (10 min), indicating a shift from early desorption to late-stage radical oxidation. Mass-balance tracking of AFB1 confirmed chemical destruction under US/Cl, with 83.4% degraded after 10 min and only 8.7% remaining in kernels and 7.9% in water. Box-Behnken response surface methodology identified practical operating windows and showed excellent fit (R² = 0.9968). Identified intermediates supported initial hydroxylation and chlorination followed by further oxidation. Soybean quality was preserved, with overlapping FTIR spectra and minimal color change (ΔE = 1.86). Overall, US/Cl provides a rapid, quality-preserving decontamination strategy for soybean kernels.