Degradation of citrinin by different types of light and hydrogen peroxide

Citrinin (CIT), a mycotoxin produced by Monascus, Penicillium, and other fungies, can contaminate red yeast rice and other foods, thus constraining their application and development. Exploring efficient degradation methods of citrinin is becoming as one of the hot research topics. In this study, the degradation of citrinin, irradiated by visible (Vis) light, ultraviolet (UV) light, and simulated sunlight alone, as well as in combination with hydrogen peroxide (light/H₂O₂), was investigated. The research demonstrates UV, Vis, and simulated sunlight all have a degree of degradation on citrinin, and the degradation efficiency correlates with light source and light intensity. Interestingly, when combined with 100 W Vis and 0.01 M H₂O₂, the citrinin degradation rate increases to 32%, compared to 1% and 5% achieved by Vis and H₂O₂ alone. Hydroxyl radicals, arising from the uniform cracking of H₂O₂ under Vis, were experimentally validated by electron spin resonance measurement and could accelerate the dissociation of citrinin by nucleophilic attacking. Employing the density functional theory, we deduced nucleophilic •OH mainly attack onto C₈ and C₅ site by comparing the electrophilic Parr functions (Pk⁺) value of main C atom of citrinin. This research presents a rapid and efficient degradation of citrinin by combining visible light with H₂O₂. PRACTICAL APPLICATION: This research presents a rapid and efficient method for the degradation of citrnin in red yeast rice and other citrnin containing products by combining visible light with H₂O₂.