Degradation and detoxification of aflatoxin B1 using nitrogen gas plasma generated by a static induction thyristor as a pulsed power supply

Abstract

Toxic fungal metabolite aflatoxin B1 (AFB1) is a stable carcinogen that is sometimes found in foods, such as peanuts and peppers. In this study, AFB1 was applied to a coverglass and subjected to treatment with nitrogen gas plasma generated by a plasma apparatus using a short high voltage pulse from a static induction thyristor power supply at 1.5 kpps (kilo pulse per second). Enzyme-linked immunosorbent assay showed that a 20 μL aliquot of a 200 ppb solution of AFB1 was efficiently degraded to less than one tenth of the original level within 15 min. High-performance liquid chromatography confirmed the loss of AFB1 after plasma treatment and the generation of small fragments, possibly originating from the degradation process. Moreover, a cell-based assay using HepG2 as an index to measure the cell-growth promoting properties of AFB1 showed that the gas plasma treatment reduced the biological activity of the mycotoxin. Although the amount of heat and ultraviolet light is insufficient to inactivate the toxin, the reactive chemical products appear to contribute to the degradation of AFB1. Controlling and optimizing the conditions for producing these reactive chemical species during plasma generation would lead to efficient inactivation of AFB1.