DISTRIBUTION OF AMMONIA AFLATOXIN REACTION-PRODUCTS IN CORN FOLLOWINGEXPOSURE TO AMMONIA DECONTAMINATION PROCEDURE

The distribution of aflatoxin decontamination reaction products in cor n following ammonia decontamination treatment was determined. The para meters of the ammoniation procedure used to decontaminate aflatoxin co ntaminated corn were 2% NH3, 16% moisture, 55 psi, 40-45-degrees-C, an d 60 min duration. Uniformly ring-labelled C-14-aflatoxin B1 was added to corn (1.0 muCi/kg) containing 7500 mug naturally-incurred aflatoxi n B1 (AFB1)/kg. Aflatoxin levels were reduced by ca 93% after ammonia treatment. Distribution of radiolabelled AFB1 was used to follow the m odification of AFB1 and the ammonia/aflatoxin reaction products were s eparated and isolated through a series of chemical extraction/partitio n procedures. Samples of the ammoniated product were fractionated thro ugh sequential extraction with methylene chloride and methanol, then e ither treated with acetic acid and sodium hydroxide or exposed to prot eolytic enzyme digestion followed by methylene chloride extraction. Ap proximately 88% of the added radioactivity was detected in the corn af ter treatment (i.e. 12% of aflatoxin reaction products were volatile), ca 20% was extracted with methylene chloride and ca 13% was extracted with methanol. Treatment with acid and base released 18.8% of the add ed radioactivity. Similar amounts (19.1%) of aflatoxin-related compoun ds were liberated after enzymatic digestion with Pronase E. The remain ing corn matrix after acid-base treatment or Pronase digestion contain ed ca 37.0% of the original radioactivity. A fluorescent spot on the T LC plate represented 6.1% of the CH2Cl2-extractable compounds and cont ained a compound which reacts chromatographically similarly to AFB2a.