Distribution of ammonia‐related aflatoxin reaction products in cottonseed meal

Abstract

AbstractThe fate of aflatoxin during ammoniation of contaminated cottonseed meal was studied under conditions approximating those approved for commercial ammoniation of nonaflatoxin‐contaminated meal. Uniformly ring‐labeled14C‐aflatoxin B1 was added to 27.7 kg meal (14% moisture) that contained ca. 4000 µg naturally incurred aflatoxin B1/kg. Distribution of the radiolabeled compound was used to trace the modification of aflatoxin B1 after treatment with 4% ammonia at 40 psi, 100 C for 30 min. This treatment reduced the chemically detected aflatoxin B1 to less than 4 µg/kg. In control nonammoniated meals, 90% of the radiolabeled material was accounted for in the methylene chloride extract. Duplicate 2‐kg samples of the ammoniated meal were fractionated and the distribution of radioactivity was determined. Ca. 86% of the radioactivity was detected in the meal after initial air‐drying. Ca. 25% of the added radioactivity was extracted from the air‐dried meal with methylene chloride and another ca. 5% was extracted from this residue with methanol. Weak acid released 3% of the added radioactivity from the residue after methanol extraction, bicarbonate released 1% and Pronase digestion, including methylene chloride extraction of the residue, accounted for nearly 19% of the total added radioactivity. Only 37% of the added radioactivity remained in the meal matrix following solvent extractions and chemical and enzymic treatments.