Effect of dietary acids on the formation of aflatoxin B_2a as a means to detoxify aflatoxin B₁

ABSTRACT

Aflatoxin B₁ (AFB₁) is a class 1 carcinogen and a common food contaminant worldwide with widely uncontrolled human exposure. The ability of organic acids to transform AFB₁ into a known detoxified form, aflatoxin B_2a (AFB_2a), was investigated using high performance liquid chromatography-electrospray ionisation-time of flight mass spectrometry (HPLC/ESI/TOF/MS). The identity of the transformation product was confirmed by accurate mass measurement, chromatographic separation from other aflatoxins, H¹-nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Of the weak acids tested, citric acid was found to be the most effective for AFB_2a formation. At room temperature, 1 M citric acid was able to convert > 97% of AFB₁ to AFB_2a over 96 h of treatment. Up to 98% transformation was achieved by boiling AFB₁ in the presence of citric acid for 20 min. AFB₁ hydration after ingestion was explored by spiking AFB₁ into simulated gastric fluid containing citric acid. Under these conditions, > 71% of AFB₁ was hydrated to AFB_2a and did not show any reversion to the parent compound after being transferred to a neutral solution. These results provide a basis for a practical and effective method for detoxification of AFB₁ in contaminated foods.

KEYWORDS:

• High-performance liquid chromatography
• time of flight mass spectrometry
• aflatoxin
• detoxification

Acknowledgements

The authors thank Ashley Wooten of the Pharmacology & Toxicology Department, Brody School of Medicine, for assistance with instrument maintenance and general laboratory management; Dr William Allen and Jordan Stanley for assistance in NMR operation and analysis; and Thomas Huff for assistance with IR operation.

Disclosure statement

No potential conflict of interest was reported by the authors.