Aflatoxin destruction by microwave heating

Abstract

Microwaves were used in the present work in order to destroy pure aflatoxins (model system), and yellow corn and peanuts containing aflatoxins (food system). Pure aflatoxins (B₁, B₂, G₁ and G₂) were individually coated on a silica gel and exposed to microwaves at various power settings and periods. The same technique was adopted for peanuts and yellow corn deliberately infected by Aspergillus flavus. The aflatoxins were extracted, fractionated by thin-layer chromatographic technique and quantitatively determined by spectrodensitometry. In all cases, the content of different aflatoxins in the deliberately infected yellow corn was in the decreasing order B₁ = G₁ > B₂ > G₂. Infected peanuts were characterized by the highest B₁ level, being approximately 3, 2, and 4.4 times as great as that in B₂, G₁ and G₂, respectively. The rate of aflatoxin destruction of model and food systems increased with the increase of microwave oven power setting (low, moderate and high) and exposure time to microwaves.