Structures of Reaction Products and Degradation Pathways of Aflatoxin B1 by Ultrasound Treatment

Abstract

Ultrasound is an emerging decontamination technology with potential use in the global food processing industry. In the present study, we explored power ultrasound for processing aqueous aflatoxin B1 (AFB1). AFB1 was degraded by 85.1% after 80 min of ultrasound exposure. The reaction products of AFB1 were identified and their molecular formulae elucidated by ultra-high-performance liquid chromatography Q-Orbitrap mass spectrometry. Eight main reaction products were found, and their structures were clarified by parental ion fragmentation. Two degradation pathways were proposed according to the degradation product structures: One involved the addition of H• and OH• radicals, whereas the other involved H2O2 epoxidation and H•, OH•, and H2O2 oxidation of AFB1. Ultrasound treatment significantly reduced AFB1 bioactivity and toxicity by disrupting the C8=C9 double bond in the furan ring and modifying the lactone ring and methoxy group.

Effect of ultrasonic pretreatment on eliminating cyanogenic glycosides and hydrogen cyanide in cassava

“…Recently, studies found that in organic or inorganic contaminants such as mycotoxins or pesticides, whose molecules were possibly involved with mechanochemical bond breakdown and rearrangement during sonication although the mechanism was not so clear yet [14] , [25] , [31] , [32] . Results showed that the increased degradation of the cyanogenic glycosides might be caused by changes in enzymatic hydrolysis promoted by ultrasound.…”

Physicochemical treatments for the reduction of aflatoxins and Aspergillus niger in corn grains (Zea mays)

“…Regarding mycotoxins, the effect of ultrasound at 20 kHz was assessed, achieving a reduction of aflatoxin contents of approximately 41% with an exposure time of 10 min 45 . In a recent study, the effect of ultrasound on the degradation of 85.1% of AFB 1 after 80 min of treatment was demonstrated; the impact of the treatment was attributed to the formation of free radicals, which led to the subsequent degradation of aflatoxin 46 …”

A review on novel non‐thermal food processing techniques for mycotoxin reduction

“…The reactive species (hydroxyl radicals and aqueous ozone) also initiates degradation by attacking the AFB 1 molecule. This is a well-known phenomenon that has been associated with the degradation of various contaminants, that is US treatment of water, in particular sonolysis, causes the covalent bonds of the water molecules to be broken yielding free radicals such as hydroxyl and hydrogen atoms, as well as hydrogen peroxide, that can oxidise contaminants in water (de Lima Leite et al, 2002;Liu et al, 2019b). As far as the effects of US treatment on the quality of food are concerned, a study by Mustapha et al (2020) demonstrated that quality profile of cherry tomato could be maintained.…”

“…In another study by Liu et al . (2019b), the authors reported an 85% degradation of AFB 1 following US treatment for 80 min and proposed a pathway for AFB 1 degradation. Mycotoxin degradation was reportedly due to free radicals generated during US treatment and not thermal degradation.…”

“…Using UHPLC Q‐Orbitrap mass spectrometry, eight degradation products were identified with two possible pathways for AFB 1 degradation. They observed that highly reactive hydroxyl radicals are generated via sonolysis, which recombine outside of the cavitation bubbles to yield hydrogen peroxide that is released into the medium (Liu et al ., 2019b). The reactive species (hydroxyl radicals and aqueous ozone) also initiates degradation by attacking the AFB 1 molecule.…”